CA1188780A - Passive display device - Google Patents
Passive display deviceInfo
- Publication number
- CA1188780A CA1188780A CA000420370A CA420370A CA1188780A CA 1188780 A CA1188780 A CA 1188780A CA 000420370 A CA000420370 A CA 000420370A CA 420370 A CA420370 A CA 420370A CA 1188780 A CA1188780 A CA 1188780A
- Authority
- CA
- Canada
- Prior art keywords
- electrodes
- layer
- display device
- electrode
- etchant
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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Classifications
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09F—DISPLAYING; ADVERTISING; SIGNS; LABELS OR NAME-PLATES; SEALS
- G09F9/00—Indicating arrangements for variable information in which the information is built-up on a support by selection or combination of individual elements
- G09F9/30—Indicating arrangements for variable information in which the information is built-up on a support by selection or combination of individual elements in which the desired character or characters are formed by combining individual elements
- G09F9/37—Indicating arrangements for variable information in which the information is built-up on a support by selection or combination of individual elements in which the desired character or characters are formed by combining individual elements being movable elements
- G09F9/372—Indicating arrangements for variable information in which the information is built-up on a support by selection or combination of individual elements in which the desired character or characters are formed by combining individual elements being movable elements the positions of the elements being controlled by the application of an electric field
Abstract
ABSTRACT:
"Passive display device."
On the facing surfaces of a first and second supporting plate, of which at least the first supporting plate is transparent, first and second electrodes, res-pectively, are provided of which at least the first electrodes are transparent. An opaque liquid is present between the supporting plates. Third electrodes (16) which can be moved between the first and second electrodes by electrostatic forces are connected to the second supporting plate. The third electrodes (16) are formed by a display part (20) having a large number of apertures (21) of which the colour of the side facing the first supporting plate is contrasting with the colour of the liquid. A number of resilient elements (22) is provided below the display part (20) one end (23) of which is con-nected to the display part (20) and the other ends (25) of which are connected to pillars (26) which are provided on the second supporting plate.
"Passive display device."
On the facing surfaces of a first and second supporting plate, of which at least the first supporting plate is transparent, first and second electrodes, res-pectively, are provided of which at least the first electrodes are transparent. An opaque liquid is present between the supporting plates. Third electrodes (16) which can be moved between the first and second electrodes by electrostatic forces are connected to the second supporting plate. The third electrodes (16) are formed by a display part (20) having a large number of apertures (21) of which the colour of the side facing the first supporting plate is contrasting with the colour of the liquid. A number of resilient elements (22) is provided below the display part (20) one end (23) of which is con-nected to the display part (20) and the other ends (25) of which are connected to pillars (26) which are provided on the second supporting plate.
Description
PHN. 10.250 The in~ention relates -to a passive dlsplay device comprising a first and a second supporting plate of which at least the first supporting plate is transparent, first:and second electrodes on the facing surface of t'he first:and second supporting plates respecti~ely, at least the first electrodes being. transparent, th.ird electrodes which comprise an apertured display part which is secured to one of the supportin.g plates by means of a number of resilient elements,:and which.third electrodes can be moved between the first:and second electrodes by electrostatic foroes,:and further comprising:an opaque liquid between the.suppor.ting plates. the colour of which liquid contrasts w.ith the colour of.the side of the third electrodes facing the fir'st supporbing pla.te. The invention:also relates to a methad of manufac.turlng such:a device. An opaque liquid is:to be understood.to mean herein:a liquid the depth of penetration o~ light in:~hich is~smaller than the distance between the supporting plates.
~ Such a passi~e display de~ice is known from our Canadian Patent 1,065,975 which issued on November 6, 1979 and is'used,.for example,.for displaying:alphanumeric information~ If.the third electrodes are present on the side of.the second electrodes, the colour of the opaque liquid'is'observed through the.transparent first supporting plate. If the.third elec.trodes:are present on the side of the.irst electrodes, howe~er, the colour of the third electrodes contrasting wi.th the liquid is observedO The .third electrodes ~hich ~re connec~ed to one of the support-in.g plates b~ means of:a n.umber of resilient elements can mo~e.between the supporting plates.by applying.a voltage on the first, second:and third electrodes. The occurring .resilient forces:are negligible with respect to the electrostatic foro.es. The.third electrodes:are electri-cally insulated from the . . . ~ ~ ..
:PIIN 10 250 2 15-7-1982 :~irst and second electrodes by an insulating layer which is provided on -the first and second electrodes~ In -the case in ~hich the ~irst and second electrodes are kept at a direct vol-tage of ~V and -V respec-tively~ or at an alter-nating voltage having an e~ective value ~, and a variablevol-tage Vg is applied to -the third electrodes, the electro-static ~orces ac-ting on the third electrodes are such that the third electrodes can a.5sume only two stable posi-tions a-t the :~irst supporting plate or the second supporting plate. l~hen a third electrode is at one o~ the supporting pla-tes~ -the voltage Vg at the -third electrode 7 dependent on the -thickness o~ -the insulating layer 9 may decrease to substan-tially ~V or -V be~ore it ~lips over to the other suppor-ting plate. As a resul-t o~ this bistable character the display device has a very large threshold vol-tage and a memory. These properties make it possible to realize large matri~ display devices. In such a matrix display de-vice the ~irst electrodes,~or example~ ~orm the row elec-trodes and the second electrodes ~orm the column electrodes 20 of the display device and all third electrodes are elec-trically interconnected. The manu~acture o~ the movable third electrodes is carried out with a so-called under cutting technique. In this techni~ue a layer is provided on an intermediate layer in ~hich layer the pattern o~ third 25 electrodes with resillent elemen-ts and apertures in the display part is etched. The ma-terial o~ -the intermediate layer is then etched away via the edges and the apertures in -the display part. This is con-tinued until only the resi-lient elements are still connected to -the substra-te by 30 means o~ a pillar. In this manner it is possible to make small resilien-tly connected electrodes which are very ~lat and are substantially ~ree from mechanical s-tres,ses. In this rnanner third electrodes having an area o~ 0.5 x 0.5 mm2 have been made with apertures of 4/um diameter and a pitch 350f 20/um. A d:isplay device having such third electrodes showed a swi-tching time o~ 25 msec at a distance be-tween the supporting pla-tes o~ 25/um and at control voltages o~
30 V.
7~
I-Iowever, the known display device suffers from the disadvantage that with smaller third electrocdes a con-siderable loss of can-trast occurs and the control charac-teristic becomes asymmetrical.
In the known display device the resilient elements with which -the third electrodes are connected to one of the supporting plates are situated beside and in the same plane as the apertured display part. As a result of -this, area is lost ~or the actual display operation. The minimum 10 possible area of the resilien-t elements is determined by the resolving power of the photo-etching methods used in manufac-turing -the third electrodes. This has ~or its resul-t that when -third electrodes become smaller the resilient elements occupy an ever increasing par-t of the area of a 15 third electrode and the display part forms an ever smaller part of the area o~ a third electrodeO When electrodes be-come smaller, the so-called whiteness, that is to say the ef*ec-tive reflecting area of a -third electrode and hence also the con-trast of the cbserved picture decreases.
In third electrodes having an area of approximate-ly 0.5 x 0.5 mm2 the resilient forces occurring as a result of -the resilient elements are small with respect to the electrostatic forces. When third elec-trodes become smaller the overall electrostatic forces decrease~ whereas as a 25 result of the decreasing size of the resilient elements the resilient forces increase considerably. In the case of smaller electrodes the resilient forces are hence no longer negligible. The result of the comparatively large resilient forces is -that an asymme-tric control characteristic is ob-30 tained which is much less ideal for matrix con-trolO
It is hence the obJect of the inven-tion to pro-vide a display device having small third electrodes with which pictures having a high contrast can be observed. For that purpose~ a display device of a kind mentioned in the 35 opening paragraph is characterized according to the inven--tion in that the resilient elements of the third elec-trodes are present below the clisplay parts of the third elec-trodes at the side remote from -the firs-t supporting pla-te. As a d~3~
PMN 10.250 L~ 16.7.1982 resul-t of -this -the whole area of a -third electrode can be used ~s a display part. As a result of -this construc -tion the whiteness has become independen-t of the size of the -third electrodes. As a result of this, smaller -third electrodes -than before can be~mall-ufactured while substan-tially maintaining contrast. Since -the resilient elements are provided below the display part, the fill area below the display elements may be used in designing the resi--lient elernentsO As a result of this larger freedom of de-sign, very small spring constants can easily be realized so -that -the occurring resilient forces are negligible with respect to the electrostatic forces even in small third electrodes. Furthermore, more resilien-t elements can be provided below the display part than is strictly lS necessary, which increases the reliability (redundance) of -the display device. Moreover~ -the accurate photo-lithographic processes, as used in the case in which the resilient elements are situa-ted in the same plane as the display par-t, are not necessary for the manuf~cture of -the resilient elements.
According to the inven-tion, display elements having small dimensions can now also be manufactured which have a-substantially ideal hysteresis cur~e with an associated large threshold voltage and a memory, These properti~s are required to realize large matrix display devices. An embodiment of such a display device is char-acterized according to the in~ention in that the first elec-trodes form a first set of strip-shaped elec-trodes, the second electrodes form a second set of strip-shaped electrodes, and the third electrodes are arranged accord-ing to columns crossing the strip~shaped electrodes of the second set substantially at right angles. The third electrodes arranged according -to columns rnay be electri-cally interconnected in a column.
The electrodes of the second set, for example, form the row electrodes and the electrodes of the third set form the column electrodes of the matrix. Such voltage . ., . , _ .
PHN 10.250 5 16.7.1982 pulses are applied to a row electrode and a col.urnn of third electrodes -that only the dlsplay element formed by a third e].ectrode at the crossing of the row elec-trode and column electrode in question flips over~l The large threshold -voltage prevents halr-selected third elec-trodes from flipping over. I-t is also possible not to interconnect the third electrodes arranged according to a column, so that each of -the -third electrodes can be driven individuallyO
A further embodiment is characterized in that the first elec-trodes form a common electrode~ As a resul-t of -this the accurate ali~nment of electrodes on -the first suppor-ting pla-te with respect to electrodes o~ the second supporting plate is avoided.
Such matrix display devices may be used, for example, for displaying television pictures, as a tele phone display, computer terminal, teletext display and generally as an alphanumeric display. The number of lines of text to be displayed depends on the number of row electrodes and the number of column electrodes per char acter.
A further embodiment is characterized in that the second suppor-ting plate is forrned by a semiconductor layer in which a set of memory elements arranged in rows and columns are provided, which memory elements can be driven and provided with inf`ormation by means of` a matrix of row electrodes and column electrodes provided on the semiconductor layer, in that the third electrodes are formed by a set of picture elec-trodes arranged in rows and columns~ and in tha-t each picture electrode is con-nected to a memory element in -the semiconductor layer.
The inforrnation is no longer written simultaneously with but separated fY-om the flipping over of the movable tl~ird electrodes The informa-tion is wrltten in the se-miconductor layer and the information f`or each pictureelement is stored in the associated memory element. The memory elements are driven and provided with information PH~ 10.250 6 1607.1982 by means o~ a matrix o~ row and column electrodes. After a row of memory elements has been provided with in~orma-tion, the next row o~ memory elements may be provided witll in~ormation since -the memory elements o~ the pre-viously driven row retain the in~ormation necessary ~orf]ipping over o~ the movable -third electrodes, It is there~ore no longer necessary ~or driving -the next row to wair until the movable third electrodes o~ the pre-vious row have rlipped over. The in~ormation is written electronically and no longer mecha-nically~ ~s a result o~ this -the in~orma-tion can be written more rapidly while -the picture corresponding to the written in:,~or-mation can also be observed more rapidly.
As explained~ small movable third electrodes can be manufactured by providing -the resilien-t elernents below -the display part. For displaying pictures having a high in~ormation density, not only small picture ele-men-ts are required but, in particular in cases in which the display device comprises a semiconductor layer ~or the rapid writing o~ information~ rapid pic-ture elements are also required. In the display elements in which the resilient elements are situated in the same plane as the display part, -the apertures in the display part should be kep-t comparatively small so as to obtain a reasonable whiteness. In the display elements according to the in~en-tion in which the resilient elements are present b010wthe display part5 the re~,,~lting higher whiteness gives a larger ~reedom with respect to the size o~ the apertures in the display part. By maintaining a reasonably large whiteness, larger apertures than before can be provided in the display part. As a result o~ the larger apertures, more rapid display elemen-ts are obtained as a resul-t o~
the reduced resistance in the liquid. The display ele-rnents formed by the movable electrodes may be o~ any suitable shape. This shape generally is a polygon and in par-ticular a square or a hexagon. In the case o~ a hexagon~ the display elements are arranged and according P~ 10.250 7 16.7.1982 to a honey-comb struc-ture. Wi.th a given intermediate space between ad~jacent display elements -the hexagonal shape has for its advan-tage, as compared with the square shape 9 that~ with the area of the display e:Lements re-maining ~he same, the area of filling is better and con-sequently the whi.teness is greater. The resilient ele-ments generally are strip-shaped. As a result of` a ra-di.ally-symmetrical arrangement of -the resilient strips 7 the displa~ element, during its displacement, cc~n rotate slightly in its plane. Such a rotation does not occur when the resilient strips are mirror-symmetrical with respect to a diagonal or a major a~is of -the display element. A further embodiment of a display device in ac~
cordance with the inven-tion is characterized in that the apertures in the display part of a third electrode have such a size that the switching time of -the third elec-trodes is smal~er -than 1/25 second. For displaying mov-ing television pictures approximately 25 f`rames per second are necessary. The size of the apertures in the display part can now be chosen to be such that the switching times of -the -third electrodes are small as compared with the picture time (1/25 sec) of a tele~ision picture. By a suitable choice of the size of the apertures~ switch-ing times smaller than, for e~ample~ 1 msec can be obtain-ed. Thus grey scales can be made by driving the third electrodes during fractions of a frame time so that the display device is sui-table for displaying blacl~-and-white television pictures.
A further embodiment is characterized in that the surfaces of the third electrodes facing -the firs-t supporting plate form at least two sets of electrodes reflecting light in different colours. By causing the surfaces of the third elec-trodes facing the first support-ing plate to reflect alternately red, green and blue light, i.-t is possible -to display colour television pic-tures.
~nother embodiment with which colour pictures .. . .
Pl~ 10.250 8 16.7.1982 can be displayed is characterized in that at least two sets o~` filters passing li.ght of different colours are provided on the first electrodes.
~ method manu-facturing a display de~ice accord-ing to the invention is characterized in -that it compris-es -the following steps-a) providing on a substrate a -first layer of a ma.terial which can be etched by means of a first etchant, b) proYiding a second layer of a ma-terlal which can be etched by means of a second etchant, c) providing the pattern of resilient elements in the se-cond layer by means of a photoetching method using the second etchant, d) providing a third layer of the same material as the first layer, e) making apertures in the third layer by means of a pho-toetching method using -the :~irst etchant at the area where the resilient elements should remain connected to a display element to be formed, f) providing a ~ourth layer of a material which can be e-tched by means of a third etchant, g) providing in the fourth layer the pattern of the dis-play part having aperture by means of a photoetching me-th~d using the third etchant, h) making, by means of the second etchant, apertures in those parts of the resilient elements which are connect-ed to the display part, the corresponding parts o-f the display part serving as a mask, and i) removing the third layer and parts o~ the first layer by undercutting ~ia the apertures and edges in the fourth and second layers by means oP -the first etchant~
~ ~urther embodiment o-f such a method is char-acterized in that a) the first layer is of aluminium, b) after providing the first layer of aluminium the regions o-f said layer which should remain connected to the supporting plate are anodized, and in that P~IN 10.250 9 16.7.1982 C) upon removing -the first la~er ~y undercutting only the non anodized parts of -the aluminium layer are etch0d away~
Still a further embodimen-t is char~cterized in tha-t the second layer is an elec-tro-deposited nlckel layer. ~s a resul-t of the electrodeposi-tion, resilien-t elements are obtained which are substantially free from mechanical stresses. Still a further embodiment is char-ac-terized in that the fourth layer is a silver layer.
The inven-tion will now be described in greater detail, by way of example, with reference to -the accom-panying drawings, in which Figures 1a and 1b are diagramma-tic drawings to explain the operation principle of the display device, lS Figure 2 is a diagrammatic sectional view of a first embodiment of a display device accordi~g to the in-vention 9 Figures 3a to 3f explain a first method of ma-nu~acturing a movable electrode, Figure 3~ explains a second method of manufac-turing a movable electrode, Figures 4a to 4d show diagrammatically a num-ber of embodiments of movable electrodes and the resi-lient elements connected thereto.
Figure 5a is a diagrammatic sectional view o~
a second embodiment of a displcay device in accordance with the invention, Figure 5b is a structure diagr~n of the device shown in Figure 5a, Figures 6a and 6b explain the principle o~ a third embodiment o~ a display device in accordance wi~h the invention, and Figure 7 shows diagrammatically a part of a fourth embodiment of a display device in accordance with the invent:ion.
Irith reference to Figures 1a and 1b the operat-ing principle will be explained of a third electrode which P~ 10 250 10 16.7.1982 is mo~~able between two electrodes by electros-ta-tic forces, as in a display device according to -the inven-tion~ Figure -la shows diagrammatically two fixed electrodes l and 2 at -a mutual distance d. A movable electrode 3 is present be-tween the elec-trodes 1 and 2 àt a distance x from elec-trode 1, Insulating layers 4 and 5 having a -thickness b d are provided on the electrodes 1 and 2. The third electrode 3 can hence move between -the extreme positions x = ~ d and x - d ~ d, where the inner face of electrode 1 represents x = 0 as shown in Fig 1b. Voltage pulses -~V and -V are applied -to the electrodes 1 and 2, while a ~ariable voltage pulse Vg is simultaneously ap-plied to the third electrode 3. ~i-th -the dielec-tric con-stan-ts of the liquid and the insula-ting layers substan-tially -the same, an electrostatic force P1 = 2 ~ ) directed towards elec-trode 2 and an electrostatic force p2 = 2 ~ ) directed towards electrode 1 is exerted on -the electrode 3 per unit area, ~ being the dielectric constant of the medium between the electrodes 1 and 2. The broken line indicating the equilibrium between said ~orces is indicated by re~er-ence numeral 8 in Figure Ib. This line 8 intersects the line x = ~dat a voltage Vg = -V -~ S V and the line x = d - ~ d at a voltage Vg _ ~V - ~ V~ The equilibrium of electrode 3 is naturally labile for when the electrode 3 is moved from the equilibrium condition over a small distance the electrostatic force between the approaching electrodes becomes larger and the elec-trostatic force between the receding electrodes becomes sm~ler. As a re-sult of this the third el~ode has only two s-table states in the range o~ voltages Vg between -V -~ ~ V and ~V - ~ V~ namely against the insulating layer 4 at x = g d and against the insulating layer 5 at x = d -~ d, For example, when the electrode 3 engages -the insulating layer 4, the voltage Vg may increase to sub-stantially V - S V before the third electrode 3 flips over to electrode 2. The voltage Vg can now decrease PI-~ 10.250 1l 16.7.1982 again -to substan-tially V + ~ ~ before the electrode 3 can f1ip back to elec-trode l. In this manner the elec--trodes 3 traverses a subs-tantially ideal hys-teresis loop which is indicated by the line 90 As a result of this the device has a large threshold ~oltage and a memory.
A first embodimen-t of a rrla-trix displ.ay de~.ice according to the invention based on the above described principle will be explained with reference to Figure 2 which is a sectional view of the device. The device com-prises -t~o parallel supporting plates 10 and 11 of which a-t least the suppor-ting plate 10 is transparent. The sup-porting plates 10 and 11 are, for example, of glass or another material, A transparent elec-trode 12 is provided on the supporting plate 10. Strip-shaped electrodes 13 are provided on the supporting plate 11. The electrodes 12 and 13 have a thickness of approximately 0.1 /um and are manufactured, for example, from indium oxide and/or tin oxide. Electrically insula-ting layers 14 and 15 of quartz, 1 to 2/um thick, are provided on the elec-trodes 12 and 13. The device further cornprises a number of nmov-able electrodes 16 shown diagrammatically which are con-nected to the insulating layer 15 by means of a number of resilient elemen-ts. The electrodes 16 are connected together in one direction by means of their resilient elements and form strip~shaped elec-trodes which cross the electrodes 13 substantially at right angles. The construction and the manufac-ture of the electrodes 16 will be described in greater de-tail wlth reference to Figure 3. The surface of the electrodes 16 facing the transparent supporting plate 10 is reflec-tive. The sup-porting plates 10 and 11 are kept spaced apar-t and -the device is sealed by an edge of sealing agent 17. The space be-tween the supporting plates 10 and 11 is filled with an opaque non-conduc-tive liquid 18 the colour of which is contrasting wi-th the diffuse-reflecting colour of the el.ectrodes 16. The l.iquid 18 is formed, for exam-ple, by a solu~tion o:f Sudan-black in toluene. By applying Pl-~ 10.250 12 16.7.1982 vol-tages to the electrodes 12, 13 and 16, the electrodes 16 can be driven from one s-tabLe s-tate to -the other. Whcn the elec-trodes 16 are presen-t against the insulating layer 1~, the ambient light is reflected by the electrod-es 16. I~hen the electrodes 16 are present against -the insulating :Layer 15, -the electrodes 16 on the si.de o~
observation are not visible through the transparen-t sup-porting pla-ta 10 and the ambient ligh-t is absorbed by the liquid 1~ or is at least re:~lected only in the colour of the liquid 18. The device forms a so-called matrix dis-play device in whic~l the st:rip-shaped electrodes 13 form, for example, the row elec-trodes and the strip shaped elec-trodes 16 f`orm the column electrodes of the device.
I~he:n a picture is written, the device is initial-ly in a state in which all third elec-trodes 16 are present on the side of the second supporting pla-te 11. The row electrodes 13 and the common e:Lectrode 12 are kept at volta.ges V and 0 volts, respectively. The row~electrodes 13 are drlven alternately with voltage p~lses whi.c~ set the voltage at the electrodes at 2~ . The information for a driven row electrode 13 is sirllultaneously presen-ted to all column electrodes~ Vol-tage pulses of 2~ are ap~
plied to the column electrodes -the electrode 16 o~ which at the crossing with the driven row electrode 13 mus-t flip over to -the first supporting plate 10, while voltage pulses o~ 2/3 V are applied to the remaining column elec-trodes, After writing, all elec-trodes 16 can be brought back to the second supporting pla-te 11 by simul-taneously bringing all column electrodes to 0 ~ ~or a short period of timeO
Figure 3a is a plan view o~ a movable electrode 16. The display part 20 thereo~ is ~ormed by a diffuse-reflecting silver layer provided with a large number of apertures 21. Four resilient elernents 22 which are shad-ed in the Figure are provided below the display part 20.
The ends o~ the resilien-t elements 22 which are co~lect-ed to the display part 20 are shown in dotted lines 230 PI-~ 10.250 13 16.7.-1982 These ends 23 have apertures which correspon~ to aper-tures 21 in the display part 20. The other ends 25 o~ the resilient elements 22 are connected -to the supporting pla-te by means o~ pillars 26. Since the resilient ele-men-ts 22 are present below the display part 20, -the com-plete sur~ace o~ the movable electrode 16 is used ~or displaying. Since ~urthermore the whole area of the dis-play par-t 20 can 'be used for designing the resilient elements 22, small spring constan-ts can be realizecl in a simple manner so that also in the case O:e electrodes having small dimensions the resilient forces are ne-gligible as compared with -the electrostatic forces. In principle two resilient elemen-ts 22 are required ~or -the movabl~ electrode 16. Because the resilient elements 22 are present below the display part, more resilient ele-ments 22 can be provided, which increases the redundancy o~ the device, because the movable elec-trode 16 keeps functioning in case one or more o~ -the resilient ele-ments 22 get out o~ working. The manufac~ure of the mov-able electrodes 16 will be e.Yplained wi-th reference to Figures 3b to 3~ which are sectional views taken on the line III - III o~ Figure 3a during the various stages o~ the manu~ac-ture~ Figure 3b shows a supporting plate 30 on which a 0.2/um thick strip-shaped electrode 31 and a 1.5/um thick insulating layer 32 is provided.
First a 0.4 /um thick aluminium layer 33 is provided on said layer and then a 0.5 /um thick nickel layer 34 is provided. The nickel layer 34 is provided by elec-tro-deposi-tion o~ said layer from a nickel sulphate 'bath.
As a ~esult o~ this a nickel layer 34 is obtained which engages the aluminium layer 33 ~ree from mechanical s*resses. The shape o~ the resilient elements 22 ls etched in the layer 34 by means o~ a pho-to-e-tching method, re~`erence numeral 23 denoting -the ends of -the resilient elements 22 which are to be connected to the display part 20 still to 'be ~ormed (Figure 3c). The mov-a'ble electrodes 16 are electrically through-connected Pl-~ '10.250 1l~ 16.7.1982 in one direction by means of t'he resilien-t elements 22 (see Figure 3a). The e-tchant is ni-tric acid which does a-t-tack -the nic'kel layer 34 'but does not attack the alu-minium laycr 33. Since the resilient elements 22 need no longer be constr~lc-ted to 'be as small as possible, ~ewer accurate photolithographic processes will suffice in manu~acturing said elements 22. A 0.3 /um thick alu-minium la~er 35 is -then provided over the nickellayer 34 and the exposed parts of`-the aluminium layer 33.
Four windo~s 36 are etched in the aluminium layer 35 at the area of -the ends 23 of`-the resilient elemen-ts 22 (see Figure 3d). A silver layer having a thickness of 0.3 /um is provided over the assembly. The pa-t-tern of` the display part 20 having apertures 2'1 is then etched in said layer by means o~ a photo-etching method (Figure 3e)0 The etchant is an iron nitrcate solution which does no-t attack the underlying aluminium lcayer 35 and the nickel layer 34. Apertures 24 are then etched in the ends 23 o~
the resilient elements 22 by means of' nitric acid, cor-responding parts of` the display part 20 serving as a mask. The aluminium layer 35 and the aluminium layer 33 are then etched away by so-called undercutting via the apertures 21 in the display part 20, the apertures 24 in the ends 23 of` the resilient elements 22, and via the edges of` the resilient elements 22. Sodium hydroxide solution is used as an etchant which does attack the alu-minium layers 35 and 33 but does not a-ttack the nickel layer 34 and the silver layer 37. Etching is discontinued at the instant at which only the ends 25 of the resilient elements 22 are s-till connected to the swppor-ting pla-te 30 by means of an aluminium pillar 26 (Figure 3f`)~
A second embodiment o~ a method of manuf'actur-ing movable electrodes will be explained with ref`erence to Figure 3~. First again an aluminium layer 33 is pro-vided on the insulating layer 32a A layer 38 of' a photo-lacquer is then provided on said layer 33 and apertures 39 are made therein in known manner, The apertures 39 PHN 10.250 15 16.7~1982 correspond to the regions 26 in the aluminium layer 33 with which the ends 25 o:~ the resilient elements 22 are connected -to the supporting pla-te 30 (see Figure 3a).
The aluminium is then anodized at the area o~ -the aper-tures 39. In the Figure these regions are re:Eerenced Llo.
The photolacquer layer 38 is then removedO For the rest the method continues as described wit'h re:~erence to Fi-gures 3b to 3:~ with the exception of the last etching step. In this case etching is carried out with concen-10 -trated phosphoric acid which does a-ttack the aluminium layers but does not at-tack the anodized regions 40.
~Tery small movable ~lectrodes 16 can be manu-:Eactured in the above~described manners. The area o:~
the display part 20 is 7 :Eor example, 200 x 200 /um and 15 the display part comprises, for example, apertures 21 having a diame-ter oE' 6 /um at a mutual di stance o-~ 20 /um.
Figures ~a to 4d show a num'ber o~ embodiments of movable electrodes 16 and the resilient element s con nected thereto/ The way in which all this is shown is 20 analogous to tha-t o~ Figure 3a, with the dif~erence that the apertures 21 in the display part 20 o~ the elec-trode 16 are not shown to avoid ambiguity o:~ -the drawing. For clarity, ~urthermore, corresponding elements are re:E'erred to by the same reference numerals as in Figure 3a. The 25 Figure 4a embodiment comprises below the display part 20 ~our strip-shaped springs 22 which are arranged radially symmetrically with respect to the centre o~ -the display part 20. The ends 23 o~ the springs 22 are connected to the display part 20. The other ends of the springs 22 30 are connec-ted to the supporting plate (not shown in the drawing) via a common part 25 by means o:E' a central pillar 26. As a result oE the radi ally symmetrica~ ar-rangement of` the springs 22, the display part 20 will rotate slightly in its own plane w'hen moved at right 35 angles to the plane o~ the drawings. Such a rotati on docs not occur in -the embodiments shown in Figures 4b to ~do II1 Figure 4b the springs 22 are mirror-symme trical P~ 10.250 16 16~7.-3982 with respect to the major axis b and in Figures 4c and 4d the springs 22 are mlrror-symmetrical with respect to a diagonal of the display part 20. The hexagonal shape of the display part 20 shown in Figure 4d, with a given in-termedia-te space d betwee~ thè adjacent display parts 20, provides a better area filling and hence a greater whiteness. The method of manufac-turing the embodiments shown in Figures 4a to 4d is analogous ~o that explained with reference to Figures 3a to 3~. The central position 0 of the pillars 26 with respect -to the display part 20 makes the embodimen-ts shown in Figure 4a to 4d particu-larly suitable for the individual driving of -the elec-trodes 16. This possibility will be described iIl greater detail with reference to the embodiments of a display ~le-vice shown in Figures 5a and 5b.
Figure 5a is a diagrammatic sectional view of the display device. The lower supporting plate is formed by a semiconductor layer 50 of, for exarnple, silicon. A
se-t of memory elements 52 arranged in rows and columns is provided in said semiconductor layer 50. The memory elements 52 may be provided with information by means of a matrix of row electrodes 53 and colwnn electrodes 54 provided on the semiconductor layer 50 and insulated from each other at the crossings. A silicon oxide layer 55 is provided over the said st-ructure and strip-shaped electrodes 56 are provided on it. An insulating quartz layer 58 on which ind~vidual resiliently connected elec-trodes 59 are provided in the same manner as described with reference to Figures 2 and 3 is provided over the electrodes 56. Each electrode 59 is connected via an aperture 57 in the layers 55 and 58 to a memory element 52. A common elec-trode 61 which is covered with an in-sulating quartz layer 62 is provided on the other sup-porting plate 60. Again an opaque liquid is present be-tween the supporting plates 50 and 60~
The op0ration of the display device will be ex-plained with reference to Figure 5b which shows a s-truc-PJ~ 10~250 17 16.7.1982 -ture diagram of the device. Each memory element is formed by a field effect transistor 65~ the ga-te and source of which are connec-tecl to a row electrode 53 and a column electrode 54 respectively. The drain of the transistor is connected -to a movable third electrocLe 59. A row elec-trode 53 is driven wi-th a positi-ve voltage pulse. The transistors 65 connected to a driven row electrode 53 hereby become conductive, The informa-tion f`or a driven row electrode 53 is simultaneously presented -to all column electrodes 54. The presented voltage pulses charge the associated electrodes 50. In this manner all row electrodes 53 are successively driven and the associated electrodes 59 are provided with charge. A charge on -the electrode 59 of a row electrode 53 cc~nnot leak away be-cause after driving a row electrode 53 the -transistors 65 again come in the non conductive state. Dependen-t on the presence or absence of a charge an electrode 59 flips over to the supporting plate 60 under the influence of -the voltage on the electrodes 56 and 61. Since writing of information occurs electronically and the write time is no longer determined by -the time necessary ~or flip-ping over of the electrodes 59, wri-ting can be done more rapidly and the picture corresponding to the written in-formation can also be observed more rapidly. Instead of a single transistor the memory elements may also be pro-vided with several transis-tors and/or capacitorsO
A third embodiment of a display device in ac-cordance wi-th the invention suitable for displaying black-and-white television pictures will be explained with re-ference to Figure 6. Figure 6a shows diagramma-tically an elementary cell ofa third electrode 82 wi-th apert-ure 83 which moves over a distance h in a cylinder 80 filled with liquid 81 between a first elec-t*ode 8L~ and a second electrode 85. A-t a voltage difference V between the firs-t electrode 84 and the second electrode 85, in which the third electrode 82 is connected -to one of said electrodes, the transit time T is given -to an approximation by the . , , . ~ " . .. .. ..
P~ 10.250 18 16.7.1982 following fo-rmula:
T = ~ D h3 wherein ~ and ~ are -the viscosi-ty and the dielectric constant of the liquid 81 7 respectively, and D and A are the diameters of the third electrode 82 and the aperture 83~ respectively and h is the distance between electrodes 84 and 85.
For a -toluene-fi:Lled device ~ = o~6 10 3 Nsec m and ~ = 2.13,10 11 F m 1. At a distance h _ 25.10 6 between the firs-t and second electrodes 84 and 85 and a diameter D - 20.10 m of the third electrode 8Z the tran-sit tirne is given by:
T = 2.22 10 (2) V A
In Figure 6~ said transit time T is plotted as a function of the diame-ter A of -the aperture 83 for the case V = 50 Volts. Also plotted in Figure 6a on the righ-t-hand side is the whiteness W, i.e. the effective reflect~ing surface of the electrode 82 as a func-tion of the dia-meter A of the aperture 83. It appears from the Figure that the realization of short transit time T, i.e~ a ra-pid display, is at the expense of the whiteness W and hence also at the expense of the contrast. It is possible, ho~ever, to manufacture rapi~ third electrodes 82 having a comparatively large contrast. In the si-tuation shol~n in Figure 6a third electrodes 8~ having a -transi-t time T =
0.88 msec have a whiteness W = 0.75.
The transit time T can still be reduced by re-ducing the dis-tance h and/or increasing the ~oltage V.
When there is a reduction of the distance h and the elec-trostatic forces on the third electrodes 82 remain the same, then the voltage V should also be reduced in which in that case, then the voltage V should also be reduced in which in that case the transit time T reduces to the P~ 10.250 19 16.7.1982 same extent as h~ Since the transit -time T is inversely proportional to ~ , the transit time T becomes still mwch smaller when the voltage V is increased.
As a resul-t of -the short transit time T, black-and-white television pictures can be displayed by means of a display device in accordance with the inven-tion. For displaying moving -television pictures subs-tantially 25 frames per second are necessary. Since switching times T
can now be realized which are small as compared with the frame -time, grey scales can be made by driving third elec-trodes 82 for fractions of a frame time.
A display device for displaying black-and-white television has the same construction as the device shown in Figure 5a~ with the difference that each memory ele-ment 52 has a counter which co-unts the mlmber of clock pulses with which the fraction is de-termined in which a third electrode is driven.
According to a fur-ther embodiment not shown the movable electrodes comprise alternately red, green and blue-reflecting surfaces with which colour television pictures can be displayed.
A further embodiment of a display device in accordance with the invention will be explained with re-ference to Figure 7 which shows diagrammatically a part o~ the display device. Again a transparen-t common elec-trode 9l is present on the transparent supporting plate90. On said electrode 91, regions 92, 93 and 94 passing light in the colours red7 green and blue are provided.
An insulating layer 9~ is provided again over said colour filters. When, for example7 a movable electrode engages a region 92, red light is reflected by said electrode.
In this rnanner it is also possible to display colour te-levision pictures, , '
~ Such a passi~e display de~ice is known from our Canadian Patent 1,065,975 which issued on November 6, 1979 and is'used,.for example,.for displaying:alphanumeric information~ If.the third electrodes are present on the side of.the second electrodes, the colour of the opaque liquid'is'observed through the.transparent first supporting plate. If the.third elec.trodes:are present on the side of the.irst electrodes, howe~er, the colour of the third electrodes contrasting wi.th the liquid is observedO The .third electrodes ~hich ~re connec~ed to one of the support-in.g plates b~ means of:a n.umber of resilient elements can mo~e.between the supporting plates.by applying.a voltage on the first, second:and third electrodes. The occurring .resilient forces:are negligible with respect to the electrostatic foro.es. The.third electrodes:are electri-cally insulated from the . . . ~ ~ ..
:PIIN 10 250 2 15-7-1982 :~irst and second electrodes by an insulating layer which is provided on -the first and second electrodes~ In -the case in ~hich the ~irst and second electrodes are kept at a direct vol-tage of ~V and -V respec-tively~ or at an alter-nating voltage having an e~ective value ~, and a variablevol-tage Vg is applied to -the third electrodes, the electro-static ~orces ac-ting on the third electrodes are such that the third electrodes can a.5sume only two stable posi-tions a-t the :~irst supporting plate or the second supporting plate. l~hen a third electrode is at one o~ the supporting pla-tes~ -the voltage Vg at the -third electrode 7 dependent on the -thickness o~ -the insulating layer 9 may decrease to substan-tially ~V or -V be~ore it ~lips over to the other suppor-ting plate. As a resul-t o~ this bistable character the display device has a very large threshold vol-tage and a memory. These properties make it possible to realize large matri~ display devices. In such a matrix display de-vice the ~irst electrodes,~or example~ ~orm the row elec-trodes and the second electrodes ~orm the column electrodes 20 of the display device and all third electrodes are elec-trically interconnected. The manu~acture o~ the movable third electrodes is carried out with a so-called under cutting technique. In this techni~ue a layer is provided on an intermediate layer in ~hich layer the pattern o~ third 25 electrodes with resillent elemen-ts and apertures in the display part is etched. The ma-terial o~ -the intermediate layer is then etched away via the edges and the apertures in -the display part. This is con-tinued until only the resi-lient elements are still connected to -the substra-te by 30 means o~ a pillar. In this manner it is possible to make small resilien-tly connected electrodes which are very ~lat and are substantially ~ree from mechanical s-tres,ses. In this rnanner third electrodes having an area o~ 0.5 x 0.5 mm2 have been made with apertures of 4/um diameter and a pitch 350f 20/um. A d:isplay device having such third electrodes showed a swi-tching time o~ 25 msec at a distance be-tween the supporting pla-tes o~ 25/um and at control voltages o~
30 V.
7~
I-Iowever, the known display device suffers from the disadvantage that with smaller third electrocdes a con-siderable loss of can-trast occurs and the control charac-teristic becomes asymmetrical.
In the known display device the resilient elements with which -the third electrodes are connected to one of the supporting plates are situated beside and in the same plane as the apertured display part. As a result of -this, area is lost ~or the actual display operation. The minimum 10 possible area of the resilien-t elements is determined by the resolving power of the photo-etching methods used in manufac-turing -the third electrodes. This has ~or its resul-t that when -third electrodes become smaller the resilient elements occupy an ever increasing par-t of the area of a 15 third electrode and the display part forms an ever smaller part of the area o~ a third electrodeO When electrodes be-come smaller, the so-called whiteness, that is to say the ef*ec-tive reflecting area of a -third electrode and hence also the con-trast of the cbserved picture decreases.
In third electrodes having an area of approximate-ly 0.5 x 0.5 mm2 the resilient forces occurring as a result of -the resilient elements are small with respect to the electrostatic forces. When third elec-trodes become smaller the overall electrostatic forces decrease~ whereas as a 25 result of the decreasing size of the resilient elements the resilient forces increase considerably. In the case of smaller electrodes the resilient forces are hence no longer negligible. The result of the comparatively large resilient forces is -that an asymme-tric control characteristic is ob-30 tained which is much less ideal for matrix con-trolO
It is hence the obJect of the inven-tion to pro-vide a display device having small third electrodes with which pictures having a high contrast can be observed. For that purpose~ a display device of a kind mentioned in the 35 opening paragraph is characterized according to the inven--tion in that the resilient elements of the third elec-trodes are present below the clisplay parts of the third elec-trodes at the side remote from -the firs-t supporting pla-te. As a d~3~
PMN 10.250 L~ 16.7.1982 resul-t of -this -the whole area of a -third electrode can be used ~s a display part. As a result of -this construc -tion the whiteness has become independen-t of the size of the -third electrodes. As a result of this, smaller -third electrodes -than before can be~mall-ufactured while substan-tially maintaining contrast. Since -the resilient elements are provided below the display part, the fill area below the display elements may be used in designing the resi--lient elernentsO As a result of this larger freedom of de-sign, very small spring constants can easily be realized so -that -the occurring resilient forces are negligible with respect to the electrostatic forces even in small third electrodes. Furthermore, more resilien-t elements can be provided below the display part than is strictly lS necessary, which increases the reliability (redundance) of -the display device. Moreover~ -the accurate photo-lithographic processes, as used in the case in which the resilient elements are situa-ted in the same plane as the display par-t, are not necessary for the manuf~cture of -the resilient elements.
According to the inven-tion, display elements having small dimensions can now also be manufactured which have a-substantially ideal hysteresis cur~e with an associated large threshold voltage and a memory, These properti~s are required to realize large matrix display devices. An embodiment of such a display device is char-acterized according to the in~ention in that the first elec-trodes form a first set of strip-shaped elec-trodes, the second electrodes form a second set of strip-shaped electrodes, and the third electrodes are arranged accord-ing to columns crossing the strip~shaped electrodes of the second set substantially at right angles. The third electrodes arranged according -to columns rnay be electri-cally interconnected in a column.
The electrodes of the second set, for example, form the row electrodes and the electrodes of the third set form the column electrodes of the matrix. Such voltage . ., . , _ .
PHN 10.250 5 16.7.1982 pulses are applied to a row electrode and a col.urnn of third electrodes -that only the dlsplay element formed by a third e].ectrode at the crossing of the row elec-trode and column electrode in question flips over~l The large threshold -voltage prevents halr-selected third elec-trodes from flipping over. I-t is also possible not to interconnect the third electrodes arranged according to a column, so that each of -the -third electrodes can be driven individuallyO
A further embodiment is characterized in that the first elec-trodes form a common electrode~ As a resul-t of -this the accurate ali~nment of electrodes on -the first suppor-ting pla-te with respect to electrodes o~ the second supporting plate is avoided.
Such matrix display devices may be used, for example, for displaying television pictures, as a tele phone display, computer terminal, teletext display and generally as an alphanumeric display. The number of lines of text to be displayed depends on the number of row electrodes and the number of column electrodes per char acter.
A further embodiment is characterized in that the second suppor-ting plate is forrned by a semiconductor layer in which a set of memory elements arranged in rows and columns are provided, which memory elements can be driven and provided with inf`ormation by means of` a matrix of row electrodes and column electrodes provided on the semiconductor layer, in that the third electrodes are formed by a set of picture elec-trodes arranged in rows and columns~ and in tha-t each picture electrode is con-nected to a memory element in -the semiconductor layer.
The inforrnation is no longer written simultaneously with but separated fY-om the flipping over of the movable tl~ird electrodes The informa-tion is wrltten in the se-miconductor layer and the information f`or each pictureelement is stored in the associated memory element. The memory elements are driven and provided with information PH~ 10.250 6 1607.1982 by means o~ a matrix o~ row and column electrodes. After a row of memory elements has been provided with in~orma-tion, the next row o~ memory elements may be provided witll in~ormation since -the memory elements o~ the pre-viously driven row retain the in~ormation necessary ~orf]ipping over o~ the movable -third electrodes, It is there~ore no longer necessary ~or driving -the next row to wair until the movable third electrodes o~ the pre-vious row have rlipped over. The in~ormation is written electronically and no longer mecha-nically~ ~s a result o~ this -the in~orma-tion can be written more rapidly while -the picture corresponding to the written in:,~or-mation can also be observed more rapidly.
As explained~ small movable third electrodes can be manufactured by providing -the resilien-t elernents below -the display part. For displaying pictures having a high in~ormation density, not only small picture ele-men-ts are required but, in particular in cases in which the display device comprises a semiconductor layer ~or the rapid writing o~ information~ rapid pic-ture elements are also required. In the display elements in which the resilient elements are situated in the same plane as the display part, -the apertures in the display part should be kep-t comparatively small so as to obtain a reasonable whiteness. In the display elements according to the in~en-tion in which the resilient elements are present b010wthe display part5 the re~,,~lting higher whiteness gives a larger ~reedom with respect to the size o~ the apertures in the display part. By maintaining a reasonably large whiteness, larger apertures than before can be provided in the display part. As a result o~ the larger apertures, more rapid display elemen-ts are obtained as a resul-t o~
the reduced resistance in the liquid. The display ele-rnents formed by the movable electrodes may be o~ any suitable shape. This shape generally is a polygon and in par-ticular a square or a hexagon. In the case o~ a hexagon~ the display elements are arranged and according P~ 10.250 7 16.7.1982 to a honey-comb struc-ture. Wi.th a given intermediate space between ad~jacent display elements -the hexagonal shape has for its advan-tage, as compared with the square shape 9 that~ with the area of the display e:Lements re-maining ~he same, the area of filling is better and con-sequently the whi.teness is greater. The resilient ele-ments generally are strip-shaped. As a result of` a ra-di.ally-symmetrical arrangement of -the resilient strips 7 the displa~ element, during its displacement, cc~n rotate slightly in its plane. Such a rotation does not occur when the resilient strips are mirror-symmetrical with respect to a diagonal or a major a~is of -the display element. A further embodiment of a display device in ac~
cordance with the inven-tion is characterized in that the apertures in the display part of a third electrode have such a size that the switching time of -the third elec-trodes is smal~er -than 1/25 second. For displaying mov-ing television pictures approximately 25 f`rames per second are necessary. The size of the apertures in the display part can now be chosen to be such that the switching times of -the -third electrodes are small as compared with the picture time (1/25 sec) of a tele~ision picture. By a suitable choice of the size of the apertures~ switch-ing times smaller than, for e~ample~ 1 msec can be obtain-ed. Thus grey scales can be made by driving the third electrodes during fractions of a frame time so that the display device is sui-table for displaying blacl~-and-white television pictures.
A further embodiment is characterized in that the surfaces of the third electrodes facing -the firs-t supporting plate form at least two sets of electrodes reflecting light in different colours. By causing the surfaces of the third elec-trodes facing the first support-ing plate to reflect alternately red, green and blue light, i.-t is possible -to display colour television pic-tures.
~nother embodiment with which colour pictures .. . .
Pl~ 10.250 8 16.7.1982 can be displayed is characterized in that at least two sets o~` filters passing li.ght of different colours are provided on the first electrodes.
~ method manu-facturing a display de~ice accord-ing to the invention is characterized in -that it compris-es -the following steps-a) providing on a substrate a -first layer of a ma.terial which can be etched by means of a first etchant, b) proYiding a second layer of a ma-terlal which can be etched by means of a second etchant, c) providing the pattern of resilient elements in the se-cond layer by means of a photoetching method using the second etchant, d) providing a third layer of the same material as the first layer, e) making apertures in the third layer by means of a pho-toetching method using -the :~irst etchant at the area where the resilient elements should remain connected to a display element to be formed, f) providing a ~ourth layer of a material which can be e-tched by means of a third etchant, g) providing in the fourth layer the pattern of the dis-play part having aperture by means of a photoetching me-th~d using the third etchant, h) making, by means of the second etchant, apertures in those parts of the resilient elements which are connect-ed to the display part, the corresponding parts o-f the display part serving as a mask, and i) removing the third layer and parts o~ the first layer by undercutting ~ia the apertures and edges in the fourth and second layers by means oP -the first etchant~
~ ~urther embodiment o-f such a method is char-acterized in that a) the first layer is of aluminium, b) after providing the first layer of aluminium the regions o-f said layer which should remain connected to the supporting plate are anodized, and in that P~IN 10.250 9 16.7.1982 C) upon removing -the first la~er ~y undercutting only the non anodized parts of -the aluminium layer are etch0d away~
Still a further embodimen-t is char~cterized in tha-t the second layer is an elec-tro-deposited nlckel layer. ~s a resul-t of the electrodeposi-tion, resilien-t elements are obtained which are substantially free from mechanical stresses. Still a further embodiment is char-ac-terized in that the fourth layer is a silver layer.
The inven-tion will now be described in greater detail, by way of example, with reference to -the accom-panying drawings, in which Figures 1a and 1b are diagramma-tic drawings to explain the operation principle of the display device, lS Figure 2 is a diagrammatic sectional view of a first embodiment of a display device accordi~g to the in-vention 9 Figures 3a to 3f explain a first method of ma-nu~acturing a movable electrode, Figure 3~ explains a second method of manufac-turing a movable electrode, Figures 4a to 4d show diagrammatically a num-ber of embodiments of movable electrodes and the resi-lient elements connected thereto.
Figure 5a is a diagrammatic sectional view o~
a second embodiment of a displcay device in accordance with the invention, Figure 5b is a structure diagr~n of the device shown in Figure 5a, Figures 6a and 6b explain the principle o~ a third embodiment o~ a display device in accordance wi~h the invention, and Figure 7 shows diagrammatically a part of a fourth embodiment of a display device in accordance with the invent:ion.
Irith reference to Figures 1a and 1b the operat-ing principle will be explained of a third electrode which P~ 10 250 10 16.7.1982 is mo~~able between two electrodes by electros-ta-tic forces, as in a display device according to -the inven-tion~ Figure -la shows diagrammatically two fixed electrodes l and 2 at -a mutual distance d. A movable electrode 3 is present be-tween the elec-trodes 1 and 2 àt a distance x from elec-trode 1, Insulating layers 4 and 5 having a -thickness b d are provided on the electrodes 1 and 2. The third electrode 3 can hence move between -the extreme positions x = ~ d and x - d ~ d, where the inner face of electrode 1 represents x = 0 as shown in Fig 1b. Voltage pulses -~V and -V are applied -to the electrodes 1 and 2, while a ~ariable voltage pulse Vg is simultaneously ap-plied to the third electrode 3. ~i-th -the dielec-tric con-stan-ts of the liquid and the insula-ting layers substan-tially -the same, an electrostatic force P1 = 2 ~ ) directed towards elec-trode 2 and an electrostatic force p2 = 2 ~ ) directed towards electrode 1 is exerted on -the electrode 3 per unit area, ~ being the dielectric constant of the medium between the electrodes 1 and 2. The broken line indicating the equilibrium between said ~orces is indicated by re~er-ence numeral 8 in Figure Ib. This line 8 intersects the line x = ~dat a voltage Vg = -V -~ S V and the line x = d - ~ d at a voltage Vg _ ~V - ~ V~ The equilibrium of electrode 3 is naturally labile for when the electrode 3 is moved from the equilibrium condition over a small distance the electrostatic force between the approaching electrodes becomes larger and the elec-trostatic force between the receding electrodes becomes sm~ler. As a re-sult of this the third el~ode has only two s-table states in the range o~ voltages Vg between -V -~ ~ V and ~V - ~ V~ namely against the insulating layer 4 at x = g d and against the insulating layer 5 at x = d -~ d, For example, when the electrode 3 engages -the insulating layer 4, the voltage Vg may increase to sub-stantially V - S V before the third electrode 3 flips over to electrode 2. The voltage Vg can now decrease PI-~ 10.250 1l 16.7.1982 again -to substan-tially V + ~ ~ before the electrode 3 can f1ip back to elec-trode l. In this manner the elec--trodes 3 traverses a subs-tantially ideal hys-teresis loop which is indicated by the line 90 As a result of this the device has a large threshold ~oltage and a memory.
A first embodimen-t of a rrla-trix displ.ay de~.ice according to the invention based on the above described principle will be explained with reference to Figure 2 which is a sectional view of the device. The device com-prises -t~o parallel supporting plates 10 and 11 of which a-t least the suppor-ting plate 10 is transparent. The sup-porting plates 10 and 11 are, for example, of glass or another material, A transparent elec-trode 12 is provided on the supporting plate 10. Strip-shaped electrodes 13 are provided on the supporting plate 11. The electrodes 12 and 13 have a thickness of approximately 0.1 /um and are manufactured, for example, from indium oxide and/or tin oxide. Electrically insula-ting layers 14 and 15 of quartz, 1 to 2/um thick, are provided on the elec-trodes 12 and 13. The device further cornprises a number of nmov-able electrodes 16 shown diagrammatically which are con-nected to the insulating layer 15 by means of a number of resilient elemen-ts. The electrodes 16 are connected together in one direction by means of their resilient elements and form strip~shaped elec-trodes which cross the electrodes 13 substantially at right angles. The construction and the manufac-ture of the electrodes 16 will be described in greater de-tail wlth reference to Figure 3. The surface of the electrodes 16 facing the transparent supporting plate 10 is reflec-tive. The sup-porting plates 10 and 11 are kept spaced apar-t and -the device is sealed by an edge of sealing agent 17. The space be-tween the supporting plates 10 and 11 is filled with an opaque non-conduc-tive liquid 18 the colour of which is contrasting wi-th the diffuse-reflecting colour of the el.ectrodes 16. The l.iquid 18 is formed, for exam-ple, by a solu~tion o:f Sudan-black in toluene. By applying Pl-~ 10.250 12 16.7.1982 vol-tages to the electrodes 12, 13 and 16, the electrodes 16 can be driven from one s-tabLe s-tate to -the other. Whcn the elec-trodes 16 are presen-t against the insulating layer 1~, the ambient light is reflected by the electrod-es 16. I~hen the electrodes 16 are present against -the insulating :Layer 15, -the electrodes 16 on the si.de o~
observation are not visible through the transparen-t sup-porting pla-ta 10 and the ambient ligh-t is absorbed by the liquid 1~ or is at least re:~lected only in the colour of the liquid 18. The device forms a so-called matrix dis-play device in whic~l the st:rip-shaped electrodes 13 form, for example, the row elec-trodes and the strip shaped elec-trodes 16 f`orm the column electrodes of the device.
I~he:n a picture is written, the device is initial-ly in a state in which all third elec-trodes 16 are present on the side of the second supporting pla-te 11. The row electrodes 13 and the common e:Lectrode 12 are kept at volta.ges V and 0 volts, respectively. The row~electrodes 13 are drlven alternately with voltage p~lses whi.c~ set the voltage at the electrodes at 2~ . The information for a driven row electrode 13 is sirllultaneously presen-ted to all column electrodes~ Vol-tage pulses of 2~ are ap~
plied to the column electrodes -the electrode 16 o~ which at the crossing with the driven row electrode 13 mus-t flip over to -the first supporting plate 10, while voltage pulses o~ 2/3 V are applied to the remaining column elec-trodes, After writing, all elec-trodes 16 can be brought back to the second supporting pla-te 11 by simul-taneously bringing all column electrodes to 0 ~ ~or a short period of timeO
Figure 3a is a plan view o~ a movable electrode 16. The display part 20 thereo~ is ~ormed by a diffuse-reflecting silver layer provided with a large number of apertures 21. Four resilient elernents 22 which are shad-ed in the Figure are provided below the display part 20.
The ends o~ the resilien-t elements 22 which are co~lect-ed to the display part 20 are shown in dotted lines 230 PI-~ 10.250 13 16.7.-1982 These ends 23 have apertures which correspon~ to aper-tures 21 in the display part 20. The other ends 25 o~ the resilient elements 22 are connected -to the supporting pla-te by means o~ pillars 26. Since the resilient ele-men-ts 22 are present below the display part 20, -the com-plete sur~ace o~ the movable electrode 16 is used ~or displaying. Since ~urthermore the whole area of the dis-play par-t 20 can 'be used for designing the resilient elements 22, small spring constan-ts can be realizecl in a simple manner so that also in the case O:e electrodes having small dimensions the resilient forces are ne-gligible as compared with -the electrostatic forces. In principle two resilient elemen-ts 22 are required ~or -the movabl~ electrode 16. Because the resilient elements 22 are present below the display part, more resilient ele-ments 22 can be provided, which increases the redundancy o~ the device, because the movable elec-trode 16 keeps functioning in case one or more o~ -the resilient ele-ments 22 get out o~ working. The manufac~ure of the mov-able electrodes 16 will be e.Yplained wi-th reference to Figures 3b to 3~ which are sectional views taken on the line III - III o~ Figure 3a during the various stages o~ the manu~ac-ture~ Figure 3b shows a supporting plate 30 on which a 0.2/um thick strip-shaped electrode 31 and a 1.5/um thick insulating layer 32 is provided.
First a 0.4 /um thick aluminium layer 33 is provided on said layer and then a 0.5 /um thick nickel layer 34 is provided. The nickel layer 34 is provided by elec-tro-deposi-tion o~ said layer from a nickel sulphate 'bath.
As a ~esult o~ this a nickel layer 34 is obtained which engages the aluminium layer 33 ~ree from mechanical s*resses. The shape o~ the resilient elements 22 ls etched in the layer 34 by means o~ a pho-to-e-tching method, re~`erence numeral 23 denoting -the ends of -the resilient elements 22 which are to be connected to the display part 20 still to 'be ~ormed (Figure 3c). The mov-a'ble electrodes 16 are electrically through-connected Pl-~ '10.250 1l~ 16.7.1982 in one direction by means of t'he resilien-t elements 22 (see Figure 3a). The e-tchant is ni-tric acid which does a-t-tack -the nic'kel layer 34 'but does not attack the alu-minium laycr 33. Since the resilient elements 22 need no longer be constr~lc-ted to 'be as small as possible, ~ewer accurate photolithographic processes will suffice in manu~acturing said elements 22. A 0.3 /um thick alu-minium la~er 35 is -then provided over the nickellayer 34 and the exposed parts of`-the aluminium layer 33.
Four windo~s 36 are etched in the aluminium layer 35 at the area of -the ends 23 of`-the resilient elemen-ts 22 (see Figure 3d). A silver layer having a thickness of 0.3 /um is provided over the assembly. The pa-t-tern of` the display part 20 having apertures 2'1 is then etched in said layer by means o~ a photo-etching method (Figure 3e)0 The etchant is an iron nitrcate solution which does no-t attack the underlying aluminium lcayer 35 and the nickel layer 34. Apertures 24 are then etched in the ends 23 o~
the resilient elements 22 by means of' nitric acid, cor-responding parts of` the display part 20 serving as a mask. The aluminium layer 35 and the aluminium layer 33 are then etched away by so-called undercutting via the apertures 21 in the display part 20, the apertures 24 in the ends 23 of` the resilient elements 22, and via the edges of` the resilient elements 22. Sodium hydroxide solution is used as an etchant which does attack the alu-minium layers 35 and 33 but does not a-ttack the nickel layer 34 and the silver layer 37. Etching is discontinued at the instant at which only the ends 25 of the resilient elements 22 are s-till connected to the swppor-ting pla-te 30 by means of an aluminium pillar 26 (Figure 3f`)~
A second embodiment o~ a method of manuf'actur-ing movable electrodes will be explained with ref`erence to Figure 3~. First again an aluminium layer 33 is pro-vided on the insulating layer 32a A layer 38 of' a photo-lacquer is then provided on said layer 33 and apertures 39 are made therein in known manner, The apertures 39 PHN 10.250 15 16.7~1982 correspond to the regions 26 in the aluminium layer 33 with which the ends 25 o:~ the resilient elements 22 are connected -to the supporting pla-te 30 (see Figure 3a).
The aluminium is then anodized at the area o~ -the aper-tures 39. In the Figure these regions are re:Eerenced Llo.
The photolacquer layer 38 is then removedO For the rest the method continues as described wit'h re:~erence to Fi-gures 3b to 3:~ with the exception of the last etching step. In this case etching is carried out with concen-10 -trated phosphoric acid which does a-ttack the aluminium layers but does not at-tack the anodized regions 40.
~Tery small movable ~lectrodes 16 can be manu-:Eactured in the above~described manners. The area o:~
the display part 20 is 7 :Eor example, 200 x 200 /um and 15 the display part comprises, for example, apertures 21 having a diame-ter oE' 6 /um at a mutual di stance o-~ 20 /um.
Figures ~a to 4d show a num'ber o~ embodiments of movable electrodes 16 and the resilient element s con nected thereto/ The way in which all this is shown is 20 analogous to tha-t o~ Figure 3a, with the dif~erence that the apertures 21 in the display part 20 o~ the elec-trode 16 are not shown to avoid ambiguity o:~ -the drawing. For clarity, ~urthermore, corresponding elements are re:E'erred to by the same reference numerals as in Figure 3a. The 25 Figure 4a embodiment comprises below the display part 20 ~our strip-shaped springs 22 which are arranged radially symmetrically with respect to the centre o~ -the display part 20. The ends 23 o~ the springs 22 are connected to the display part 20. The other ends of the springs 22 30 are connec-ted to the supporting plate (not shown in the drawing) via a common part 25 by means o:E' a central pillar 26. As a result oE the radi ally symmetrica~ ar-rangement of` the springs 22, the display part 20 will rotate slightly in its own plane w'hen moved at right 35 angles to the plane o~ the drawings. Such a rotati on docs not occur in -the embodiments shown in Figures 4b to ~do II1 Figure 4b the springs 22 are mirror-symme trical P~ 10.250 16 16~7.-3982 with respect to the major axis b and in Figures 4c and 4d the springs 22 are mlrror-symmetrical with respect to a diagonal of the display part 20. The hexagonal shape of the display part 20 shown in Figure 4d, with a given in-termedia-te space d betwee~ thè adjacent display parts 20, provides a better area filling and hence a greater whiteness. The method of manufac-turing the embodiments shown in Figures 4a to 4d is analogous ~o that explained with reference to Figures 3a to 3~. The central position 0 of the pillars 26 with respect -to the display part 20 makes the embodimen-ts shown in Figure 4a to 4d particu-larly suitable for the individual driving of -the elec-trodes 16. This possibility will be described iIl greater detail with reference to the embodiments of a display ~le-vice shown in Figures 5a and 5b.
Figure 5a is a diagrammatic sectional view of the display device. The lower supporting plate is formed by a semiconductor layer 50 of, for exarnple, silicon. A
se-t of memory elements 52 arranged in rows and columns is provided in said semiconductor layer 50. The memory elements 52 may be provided with information by means of a matrix of row electrodes 53 and colwnn electrodes 54 provided on the semiconductor layer 50 and insulated from each other at the crossings. A silicon oxide layer 55 is provided over the said st-ructure and strip-shaped electrodes 56 are provided on it. An insulating quartz layer 58 on which ind~vidual resiliently connected elec-trodes 59 are provided in the same manner as described with reference to Figures 2 and 3 is provided over the electrodes 56. Each electrode 59 is connected via an aperture 57 in the layers 55 and 58 to a memory element 52. A common elec-trode 61 which is covered with an in-sulating quartz layer 62 is provided on the other sup-porting plate 60. Again an opaque liquid is present be-tween the supporting plates 50 and 60~
The op0ration of the display device will be ex-plained with reference to Figure 5b which shows a s-truc-PJ~ 10~250 17 16.7.1982 -ture diagram of the device. Each memory element is formed by a field effect transistor 65~ the ga-te and source of which are connec-tecl to a row electrode 53 and a column electrode 54 respectively. The drain of the transistor is connected -to a movable third electrocLe 59. A row elec-trode 53 is driven wi-th a positi-ve voltage pulse. The transistors 65 connected to a driven row electrode 53 hereby become conductive, The informa-tion f`or a driven row electrode 53 is simultaneously presented -to all column electrodes 54. The presented voltage pulses charge the associated electrodes 50. In this manner all row electrodes 53 are successively driven and the associated electrodes 59 are provided with charge. A charge on -the electrode 59 of a row electrode 53 cc~nnot leak away be-cause after driving a row electrode 53 the -transistors 65 again come in the non conductive state. Dependen-t on the presence or absence of a charge an electrode 59 flips over to the supporting plate 60 under the influence of -the voltage on the electrodes 56 and 61. Since writing of information occurs electronically and the write time is no longer determined by -the time necessary ~or flip-ping over of the electrodes 59, wri-ting can be done more rapidly and the picture corresponding to the written in-formation can also be observed more rapidly. Instead of a single transistor the memory elements may also be pro-vided with several transis-tors and/or capacitorsO
A third embodiment of a display device in ac-cordance wi-th the invention suitable for displaying black-and-white television pictures will be explained with re-ference to Figure 6. Figure 6a shows diagramma-tically an elementary cell ofa third electrode 82 wi-th apert-ure 83 which moves over a distance h in a cylinder 80 filled with liquid 81 between a first elec-t*ode 8L~ and a second electrode 85. A-t a voltage difference V between the firs-t electrode 84 and the second electrode 85, in which the third electrode 82 is connected -to one of said electrodes, the transit time T is given -to an approximation by the . , , . ~ " . .. .. ..
P~ 10.250 18 16.7.1982 following fo-rmula:
T = ~ D h3 wherein ~ and ~ are -the viscosi-ty and the dielectric constant of the liquid 81 7 respectively, and D and A are the diameters of the third electrode 82 and the aperture 83~ respectively and h is the distance between electrodes 84 and 85.
For a -toluene-fi:Lled device ~ = o~6 10 3 Nsec m and ~ = 2.13,10 11 F m 1. At a distance h _ 25.10 6 between the firs-t and second electrodes 84 and 85 and a diameter D - 20.10 m of the third electrode 8Z the tran-sit tirne is given by:
T = 2.22 10 (2) V A
In Figure 6~ said transit time T is plotted as a function of the diame-ter A of -the aperture 83 for the case V = 50 Volts. Also plotted in Figure 6a on the righ-t-hand side is the whiteness W, i.e. the effective reflect~ing surface of the electrode 82 as a func-tion of the dia-meter A of the aperture 83. It appears from the Figure that the realization of short transit time T, i.e~ a ra-pid display, is at the expense of the whiteness W and hence also at the expense of the contrast. It is possible, ho~ever, to manufacture rapi~ third electrodes 82 having a comparatively large contrast. In the si-tuation shol~n in Figure 6a third electrodes 8~ having a -transi-t time T =
0.88 msec have a whiteness W = 0.75.
The transit time T can still be reduced by re-ducing the dis-tance h and/or increasing the ~oltage V.
When there is a reduction of the distance h and the elec-trostatic forces on the third electrodes 82 remain the same, then the voltage V should also be reduced in which in that case, then the voltage V should also be reduced in which in that case the transit time T reduces to the P~ 10.250 19 16.7.1982 same extent as h~ Since the transit -time T is inversely proportional to ~ , the transit time T becomes still mwch smaller when the voltage V is increased.
As a resul-t of -the short transit time T, black-and-white television pictures can be displayed by means of a display device in accordance with the inven-tion. For displaying moving -television pictures subs-tantially 25 frames per second are necessary. Since switching times T
can now be realized which are small as compared with the frame -time, grey scales can be made by driving third elec-trodes 82 for fractions of a frame time.
A display device for displaying black-and-white television has the same construction as the device shown in Figure 5a~ with the difference that each memory ele-ment 52 has a counter which co-unts the mlmber of clock pulses with which the fraction is de-termined in which a third electrode is driven.
According to a fur-ther embodiment not shown the movable electrodes comprise alternately red, green and blue-reflecting surfaces with which colour television pictures can be displayed.
A further embodiment of a display device in accordance with the invention will be explained with re-ference to Figure 7 which shows diagrammatically a part o~ the display device. Again a transparen-t common elec-trode 9l is present on the transparent supporting plate90. On said electrode 91, regions 92, 93 and 94 passing light in the colours red7 green and blue are provided.
An insulating layer 9~ is provided again over said colour filters. When, for example7 a movable electrode engages a region 92, red light is reflected by said electrode.
In this rnanner it is also possible to display colour te-levision pictures, , '
Claims (14)
1. A passive display device comprising A first and a second supporting plate of which at least the third support-ing plate is transparent, first and second electrodes on the facing surfaces of the first and the second supporting plates respectively, at least the first electrodes being transparent, third electrodes which comprise an apertured display part which is secured to one of the supporting plates by means of a number of resilient elements, and which -third electrodes are movable between the first and second electrodes by electrostatic forces, and further com-prising an opaque liquid between the supporting plates the colour of which liquid contrasts with the colour of the side of the third electrodes facing the first supporting plate, characterized in that the resilient elements of the third electrodes are present below the display part of the third electrodes at the side remote from the first supporting plate.
2. A passive display device as claimed in Claim 1, characterized in that the first electrodes form a first set of strip-shaped electrodes, the second electrodes form a second set of strip-shaped electrodes and the third electrodes are arranged according to columns cross-ing.the electrodes of the second set substantially at right angles.
3.. A passive display device as claimed in Claim 1, characterized in that the third electrodes in a column are electrically interconnected.
4. A passive display device as claimed in Claim 1, characterized in that the first electrodes form a common electrode.
5. A passiye display device as claimed in Claim 1, characterized in that the display parts of the third electrodes have a polygonal shape.
6. A positive display device as claimed in Claim 5, characterized in that the polygon is a hexagon.
7. A passive display device as claimed in Claim 1, characterized in that the second supporting plate is formed by a semiconductor layer in which a set of memory elements arranged in rows and columns are provided which memory elements can be driven and provided with information by means of a matrix of row and column electrodes provided on the semiconductor layer, that the third electrodes are formed by a set of picture electrodes arranged in rows and columns, and that each picture electrode is connected to a memory element in the semiconductor layer.
8. A passive display device as claimed in Claim 1, characterized in that the apertures in the display part of a third electrode have such a size that the switching time of the third electrode is smaller than 1/25 second.
9. A passive display device as claimed in Claim 1, characterized in that the surfaces of the third electrodes facing.the first supporting plate form at least two sets of electrodes reflecting light in different colours.
10. A passive display device as claimed in Claim 1, characterized in that at least two sets of filters passing light in different colours are provided on the first electrodes.
11. A method of manufacturing a display device as claimed in Claim 1, characterized in that the method com-prises the following steps:
a) providing on a substrate a first layer of a material which can be etched by means of a first etchant, b) providing a second layer of a material which can be etched by means of a second etchant, c) providing the pattern of resilient elements in the second layer by means of a photo etching method using the second etchant, d) providing a third layer of the same material as the first layer, e) making apertures in the third layer by means of a photo-etching method using the first etchant at the area where the resilient element should remain connected to a display element to be formed, f) providing a fourth layer of a material which can be etched by means of a third etchant, g) providing in the fourth layer the pattern of the display part having apertures by means of a photo-etching method using the third etchant, h) making, by means of a second etchant apertures in those parts of the resilient elements which are con-nected to the display part, the corresponding parts of the display part serving as a mask, and i) removing the third layer and parts of the first layer by undercutting via the apertures and edges in the fourth and second layers by means of the first etchant.
a) providing on a substrate a first layer of a material which can be etched by means of a first etchant, b) providing a second layer of a material which can be etched by means of a second etchant, c) providing the pattern of resilient elements in the second layer by means of a photo etching method using the second etchant, d) providing a third layer of the same material as the first layer, e) making apertures in the third layer by means of a photo-etching method using the first etchant at the area where the resilient element should remain connected to a display element to be formed, f) providing a fourth layer of a material which can be etched by means of a third etchant, g) providing in the fourth layer the pattern of the display part having apertures by means of a photo-etching method using the third etchant, h) making, by means of a second etchant apertures in those parts of the resilient elements which are con-nected to the display part, the corresponding parts of the display part serving as a mask, and i) removing the third layer and parts of the first layer by undercutting via the apertures and edges in the fourth and second layers by means of the first etchant.
12. A method as claimed in Claim 11, characterized in that a) the first layer is of aluminium, b) after providing the first layer of aluminium the regions of said layer which should remain connected to the supporting plate are an odized, and in that c) upon removing the first layer by undercutting only the non-anodized parts of the aluminium layer are etched away.
13. A method as claimed in Claim 11, characterized in that the second layer is an electro-deposited nickel layer.
14. A method as claimed in, Claim 11, characterized in, that the fourth layer is a silver layer.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NL8200354 | 1982-02-01 | ||
| NL8200354A NL8200354A (en) | 1982-02-01 | 1982-02-01 | PASSIVE DISPLAY. |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1188780A true CA1188780A (en) | 1985-06-11 |
Family
ID=19839165
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000420370A Expired CA1188780A (en) | 1982-02-01 | 1983-01-27 | Passive display device |
Country Status (8)
| Country | Link |
|---|---|
| US (1) | US4519676A (en) |
| EP (1) | EP0085459B1 (en) |
| JP (1) | JPS58132782A (en) |
| CA (1) | CA1188780A (en) |
| DE (1) | DE3363454D1 (en) |
| ES (2) | ES519356A0 (en) |
| HK (1) | HK4987A (en) |
| NL (1) | NL8200354A (en) |
Families Citing this family (196)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| NL8402038A (en) * | 1984-06-28 | 1986-01-16 | Philips Nv | ELECTROSCOPIC IMAGE DISPLAY DEVICE. |
| NL8402201A (en) * | 1984-07-12 | 1986-02-03 | Philips Nv | PASSIVE DISPLAY. |
| NL8402937A (en) * | 1984-09-27 | 1986-04-16 | Philips Nv | ELECTROSCOPIC IMAGE DISPLAY DEVICE. |
| NL8403077A (en) * | 1984-10-10 | 1986-05-01 | Philips Nv | ELECTROSCOPIC FLUID IMAGE DISPLAY FITTED FOR TELEVISION. |
| NL8403536A (en) * | 1984-11-21 | 1986-06-16 | Philips Nv | PASSIVE DISPLAY. |
| CA1270639A (en) * | 1985-10-03 | 1990-06-26 | Roger S. Kent | Display member |
| NL8600697A (en) * | 1986-01-09 | 1987-08-03 | Philips Nv | IMAGE DISPLAY DEVICE AND A METHOD FOR MANUFACTURING IT. |
| US5835255A (en) * | 1986-04-23 | 1998-11-10 | Etalon, Inc. | Visible spectrum modulator arrays |
| CH682523A5 (en) * | 1990-04-20 | 1993-09-30 | Suisse Electronique Microtech | A modulation matrix addressed light. |
| US5142405A (en) * | 1990-06-29 | 1992-08-25 | Texas Instruments Incorporated | Bistable dmd addressing circuit and method |
| US5899709A (en) * | 1992-04-07 | 1999-05-04 | Semiconductor Energy Laboratory Co., Ltd. | Method for forming a semiconductor device using anodic oxidation |
| US6674562B1 (en) | 1994-05-05 | 2004-01-06 | Iridigm Display Corporation | Interferometric modulation of radiation |
| US7297471B1 (en) | 2003-04-15 | 2007-11-20 | Idc, Llc | Method for manufacturing an array of interferometric modulators |
| US7138984B1 (en) | 2001-06-05 | 2006-11-21 | Idc, Llc | Directly laminated touch sensitive screen |
| US20010003487A1 (en) * | 1996-11-05 | 2001-06-14 | Mark W. Miles | Visible spectrum modulator arrays |
| US7460291B2 (en) * | 1994-05-05 | 2008-12-02 | Idc, Llc | Separable modulator |
| US7550794B2 (en) | 2002-09-20 | 2009-06-23 | Idc, Llc | Micromechanical systems device comprising a displaceable electrode and a charge-trapping layer |
| US8014059B2 (en) | 1994-05-05 | 2011-09-06 | Qualcomm Mems Technologies, Inc. | System and method for charge control in a MEMS device |
| US7123216B1 (en) | 1994-05-05 | 2006-10-17 | Idc, Llc | Photonic MEMS and structures |
| US6710908B2 (en) | 1994-05-05 | 2004-03-23 | Iridigm Display Corporation | Controlling micro-electro-mechanical cavities |
| US6040937A (en) * | 1994-05-05 | 2000-03-21 | Etalon, Inc. | Interferometric modulation |
| US6680792B2 (en) | 1994-05-05 | 2004-01-20 | Iridigm Display Corporation | Interferometric modulation of radiation |
| US7907319B2 (en) | 1995-11-06 | 2011-03-15 | Qualcomm Mems Technologies, Inc. | Method and device for modulating light with optical compensation |
| US7471444B2 (en) | 1996-12-19 | 2008-12-30 | Idc, Llc | Interferometric modulation of radiation |
| US8928967B2 (en) | 1998-04-08 | 2015-01-06 | Qualcomm Mems Technologies, Inc. | Method and device for modulating light |
| KR100703140B1 (en) | 1998-04-08 | 2007-04-05 | 이리다임 디스플레이 코포레이션 | Interferometric modulation and its manufacturing method |
| US7532377B2 (en) | 1998-04-08 | 2009-05-12 | Idc, Llc | Movable micro-electromechanical device |
| US6323834B1 (en) | 1998-10-08 | 2001-11-27 | International Business Machines Corporation | Micromechanical displays and fabrication method |
| US8023724B2 (en) * | 1999-07-22 | 2011-09-20 | Photon-X, Inc. | Apparatus and method of information extraction from electromagnetic energy based upon multi-characteristic spatial geometry processing |
| WO2003007049A1 (en) * | 1999-10-05 | 2003-01-23 | Iridigm Display Corporation | Photonic mems and structures |
| US6962771B1 (en) * | 2000-10-13 | 2005-11-08 | Taiwan Semiconductor Manufacturing Company, Ltd. | Dual damascene process |
| US6589625B1 (en) | 2001-08-01 | 2003-07-08 | Iridigm Display Corporation | Hermetic seal and method to create the same |
| US6794119B2 (en) | 2002-02-12 | 2004-09-21 | Iridigm Display Corporation | Method for fabricating a structure for a microelectromechanical systems (MEMS) device |
| US6574033B1 (en) | 2002-02-27 | 2003-06-03 | Iridigm Display Corporation | Microelectromechanical systems device and method for fabricating same |
| JP2003307756A (en) * | 2002-04-15 | 2003-10-31 | Canon Inc | Electro-deposition display device |
| US7781850B2 (en) | 2002-09-20 | 2010-08-24 | Qualcomm Mems Technologies, Inc. | Controlling electromechanical behavior of structures within a microelectromechanical systems device |
| US6844960B2 (en) * | 2002-09-24 | 2005-01-18 | Eastman Kodak Company | Microelectromechanical device with continuously variable displacement |
| TWI289708B (en) | 2002-12-25 | 2007-11-11 | Qualcomm Mems Technologies Inc | Optical interference type color display |
| TW200413810A (en) | 2003-01-29 | 2004-08-01 | Prime View Int Co Ltd | Light interference display panel and its manufacturing method |
| TW594360B (en) | 2003-04-21 | 2004-06-21 | Prime View Int Corp Ltd | A method for fabricating an interference display cell |
| TW570896B (en) | 2003-05-26 | 2004-01-11 | Prime View Int Co Ltd | A method for fabricating an interference display cell |
| US7221495B2 (en) * | 2003-06-24 | 2007-05-22 | Idc Llc | Thin film precursor stack for MEMS manufacturing |
| TWI231865B (en) | 2003-08-26 | 2005-05-01 | Prime View Int Co Ltd | An interference display cell and fabrication method thereof |
| TW593126B (en) | 2003-09-30 | 2004-06-21 | Prime View Int Co Ltd | A structure of a micro electro mechanical system and manufacturing the same |
| US7012726B1 (en) | 2003-11-03 | 2006-03-14 | Idc, Llc | MEMS devices with unreleased thin film components |
| US7161728B2 (en) | 2003-12-09 | 2007-01-09 | Idc, Llc | Area array modulation and lead reduction in interferometric modulators |
| US7142346B2 (en) * | 2003-12-09 | 2006-11-28 | Idc, Llc | System and method for addressing a MEMS display |
| US7532194B2 (en) * | 2004-02-03 | 2009-05-12 | Idc, Llc | Driver voltage adjuster |
| US7342705B2 (en) | 2004-02-03 | 2008-03-11 | Idc, Llc | Spatial light modulator with integrated optical compensation structure |
| US7119945B2 (en) * | 2004-03-03 | 2006-10-10 | Idc, Llc | Altering temporal response of microelectromechanical elements |
| US7706050B2 (en) | 2004-03-05 | 2010-04-27 | Qualcomm Mems Technologies, Inc. | Integrated modulator illumination |
| US7476327B2 (en) | 2004-05-04 | 2009-01-13 | Idc, Llc | Method of manufacture for microelectromechanical devices |
| US7060895B2 (en) | 2004-05-04 | 2006-06-13 | Idc, Llc | Modifying the electro-mechanical behavior of devices |
| US7164520B2 (en) * | 2004-05-12 | 2007-01-16 | Idc, Llc | Packaging for an interferometric modulator |
| US7256922B2 (en) | 2004-07-02 | 2007-08-14 | Idc, Llc | Interferometric modulators with thin film transistors |
| KR101354520B1 (en) * | 2004-07-29 | 2014-01-21 | 퀄컴 엠이엠에스 테크놀로지스, 인크. | System and method for micro-electromechanical operating of an interferometric modulator |
| US7560299B2 (en) | 2004-08-27 | 2009-07-14 | Idc, Llc | Systems and methods of actuating MEMS display elements |
| US7551159B2 (en) * | 2004-08-27 | 2009-06-23 | Idc, Llc | System and method of sensing actuation and release voltages of an interferometric modulator |
| US7499208B2 (en) | 2004-08-27 | 2009-03-03 | Udc, Llc | Current mode display driver circuit realization feature |
| US7515147B2 (en) | 2004-08-27 | 2009-04-07 | Idc, Llc | Staggered column drive circuit systems and methods |
| US7889163B2 (en) | 2004-08-27 | 2011-02-15 | Qualcomm Mems Technologies, Inc. | Drive method for MEMS devices |
| US7602375B2 (en) * | 2004-09-27 | 2009-10-13 | Idc, Llc | Method and system for writing data to MEMS display elements |
| US7675669B2 (en) * | 2004-09-27 | 2010-03-09 | Qualcomm Mems Technologies, Inc. | Method and system for driving interferometric modulators |
| US7415186B2 (en) | 2004-09-27 | 2008-08-19 | Idc, Llc | Methods for visually inspecting interferometric modulators for defects |
| US8878825B2 (en) | 2004-09-27 | 2014-11-04 | Qualcomm Mems Technologies, Inc. | System and method for providing a variable refresh rate of an interferometric modulator display |
| US7460246B2 (en) | 2004-09-27 | 2008-12-02 | Idc, Llc | Method and system for sensing light using interferometric elements |
| US7586484B2 (en) | 2004-09-27 | 2009-09-08 | Idc, Llc | Controller and driver features for bi-stable display |
| US7369294B2 (en) | 2004-09-27 | 2008-05-06 | Idc, Llc | Ornamental display device |
| US7653371B2 (en) | 2004-09-27 | 2010-01-26 | Qualcomm Mems Technologies, Inc. | Selectable capacitance circuit |
| US8008736B2 (en) | 2004-09-27 | 2011-08-30 | Qualcomm Mems Technologies, Inc. | Analog interferometric modulator device |
| US7692839B2 (en) | 2004-09-27 | 2010-04-06 | Qualcomm Mems Technologies, Inc. | System and method of providing MEMS device with anti-stiction coating |
| US7701631B2 (en) | 2004-09-27 | 2010-04-20 | Qualcomm Mems Technologies, Inc. | Device having patterned spacers for backplates and method of making the same |
| US7944599B2 (en) | 2004-09-27 | 2011-05-17 | Qualcomm Mems Technologies, Inc. | Electromechanical device with optical function separated from mechanical and electrical function |
| US7405924B2 (en) | 2004-09-27 | 2008-07-29 | Idc, Llc | System and method for protecting microelectromechanical systems array using structurally reinforced back-plate |
| US7843410B2 (en) | 2004-09-27 | 2010-11-30 | Qualcomm Mems Technologies, Inc. | Method and device for electrically programmable display |
| US7359066B2 (en) | 2004-09-27 | 2008-04-15 | Idc, Llc | Electro-optical measurement of hysteresis in interferometric modulators |
| US7583429B2 (en) | 2004-09-27 | 2009-09-01 | Idc, Llc | Ornamental display device |
| US7420725B2 (en) | 2004-09-27 | 2008-09-02 | Idc, Llc | Device having a conductive light absorbing mask and method for fabricating same |
| US7136213B2 (en) | 2004-09-27 | 2006-11-14 | Idc, Llc | Interferometric modulators having charge persistence |
| US7310179B2 (en) * | 2004-09-27 | 2007-12-18 | Idc, Llc | Method and device for selective adjustment of hysteresis window |
| US7161730B2 (en) | 2004-09-27 | 2007-01-09 | Idc, Llc | System and method for providing thermal compensation for an interferometric modulator display |
| US7679627B2 (en) | 2004-09-27 | 2010-03-16 | Qualcomm Mems Technologies, Inc. | Controller and driver features for bi-stable display |
| US7130104B2 (en) | 2004-09-27 | 2006-10-31 | Idc, Llc | Methods and devices for inhibiting tilting of a mirror in an interferometric modulator |
| US7554714B2 (en) | 2004-09-27 | 2009-06-30 | Idc, Llc | Device and method for manipulation of thermal response in a modulator |
| US7936497B2 (en) | 2004-09-27 | 2011-05-03 | Qualcomm Mems Technologies, Inc. | MEMS device having deformable membrane characterized by mechanical persistence |
| US7345805B2 (en) | 2004-09-27 | 2008-03-18 | Idc, Llc | Interferometric modulator array with integrated MEMS electrical switches |
| US7349136B2 (en) | 2004-09-27 | 2008-03-25 | Idc, Llc | Method and device for a display having transparent components integrated therein |
| US20060176487A1 (en) | 2004-09-27 | 2006-08-10 | William Cummings | Process control monitors for interferometric modulators |
| US7492502B2 (en) | 2004-09-27 | 2009-02-17 | Idc, Llc | Method of fabricating a free-standing microstructure |
| US7369296B2 (en) * | 2004-09-27 | 2008-05-06 | Idc, Llc | Device and method for modifying actuation voltage thresholds of a deformable membrane in an interferometric modulator |
| US7446927B2 (en) | 2004-09-27 | 2008-11-04 | Idc, Llc | MEMS switch with set and latch electrodes |
| US20060077126A1 (en) * | 2004-09-27 | 2006-04-13 | Manish Kothari | Apparatus and method for arranging devices into an interconnected array |
| US7373026B2 (en) | 2004-09-27 | 2008-05-13 | Idc, Llc | MEMS device fabricated on a pre-patterned substrate |
| US7916103B2 (en) * | 2004-09-27 | 2011-03-29 | Qualcomm Mems Technologies, Inc. | System and method for display device with end-of-life phenomena |
| US7535466B2 (en) | 2004-09-27 | 2009-05-19 | Idc, Llc | System with server based control of client device display features |
| US7626581B2 (en) | 2004-09-27 | 2009-12-01 | Idc, Llc | Device and method for display memory using manipulation of mechanical response |
| US7417735B2 (en) | 2004-09-27 | 2008-08-26 | Idc, Llc | Systems and methods for measuring color and contrast in specular reflective devices |
| US7564612B2 (en) | 2004-09-27 | 2009-07-21 | Idc, Llc | Photonic MEMS and structures |
| US7289259B2 (en) | 2004-09-27 | 2007-10-30 | Idc, Llc | Conductive bus structure for interferometric modulator array |
| US7532195B2 (en) | 2004-09-27 | 2009-05-12 | Idc, Llc | Method and system for reducing power consumption in a display |
| US7259449B2 (en) * | 2004-09-27 | 2007-08-21 | Idc, Llc | Method and system for sealing a substrate |
| US7304784B2 (en) | 2004-09-27 | 2007-12-04 | Idc, Llc | Reflective display device having viewable display on both sides |
| US7893919B2 (en) | 2004-09-27 | 2011-02-22 | Qualcomm Mems Technologies, Inc. | Display region architectures |
| US7405861B2 (en) | 2004-09-27 | 2008-07-29 | Idc, Llc | Method and device for protecting interferometric modulators from electrostatic discharge |
| US7368803B2 (en) | 2004-09-27 | 2008-05-06 | Idc, Llc | System and method for protecting microelectromechanical systems array using back-plate with non-flat portion |
| US7343080B2 (en) | 2004-09-27 | 2008-03-11 | Idc, Llc | System and method of testing humidity in a sealed MEMS device |
| US7424198B2 (en) | 2004-09-27 | 2008-09-09 | Idc, Llc | Method and device for packaging a substrate |
| US7527995B2 (en) | 2004-09-27 | 2009-05-05 | Qualcomm Mems Technologies, Inc. | Method of making prestructure for MEMS systems |
| US7355780B2 (en) | 2004-09-27 | 2008-04-08 | Idc, Llc | System and method of illuminating interferometric modulators using backlighting |
| WO2006037044A1 (en) * | 2004-09-27 | 2006-04-06 | Idc, Llc | Method and device for multistate interferometric light modulation |
| US7545550B2 (en) | 2004-09-27 | 2009-06-09 | Idc, Llc | Systems and methods of actuating MEMS display elements |
| US7317568B2 (en) | 2004-09-27 | 2008-01-08 | Idc, Llc | System and method of implementation of interferometric modulators for display mirrors |
| US7710629B2 (en) * | 2004-09-27 | 2010-05-04 | Qualcomm Mems Technologies, Inc. | System and method for display device with reinforcing substance |
| US7808703B2 (en) | 2004-09-27 | 2010-10-05 | Qualcomm Mems Technologies, Inc. | System and method for implementation of interferometric modulator displays |
| US7630119B2 (en) | 2004-09-27 | 2009-12-08 | Qualcomm Mems Technologies, Inc. | Apparatus and method for reducing slippage between structures in an interferometric modulator |
| US7553684B2 (en) | 2004-09-27 | 2009-06-30 | Idc, Llc | Method of fabricating interferometric devices using lift-off processing techniques |
| US7813026B2 (en) | 2004-09-27 | 2010-10-12 | Qualcomm Mems Technologies, Inc. | System and method of reducing color shift in a display |
| US7920135B2 (en) | 2004-09-27 | 2011-04-05 | Qualcomm Mems Technologies, Inc. | Method and system for driving a bi-stable display |
| US7684104B2 (en) | 2004-09-27 | 2010-03-23 | Idc, Llc | MEMS using filler material and method |
| US7372613B2 (en) | 2004-09-27 | 2008-05-13 | Idc, Llc | Method and device for multistate interferometric light modulation |
| US7668415B2 (en) | 2004-09-27 | 2010-02-23 | Qualcomm Mems Technologies, Inc. | Method and device for providing electronic circuitry on a backplate |
| US20060076634A1 (en) | 2004-09-27 | 2006-04-13 | Lauren Palmateer | Method and system for packaging MEMS devices with incorporated getter |
| US7429334B2 (en) | 2004-09-27 | 2008-09-30 | Idc, Llc | Methods of fabricating interferometric modulators by selectively removing a material |
| US7719500B2 (en) | 2004-09-27 | 2010-05-18 | Qualcomm Mems Technologies, Inc. | Reflective display pixels arranged in non-rectangular arrays |
| US8310441B2 (en) | 2004-09-27 | 2012-11-13 | Qualcomm Mems Technologies, Inc. | Method and system for writing data to MEMS display elements |
| US7299681B2 (en) | 2004-09-27 | 2007-11-27 | Idc, Llc | Method and system for detecting leak in electronic devices |
| US7453579B2 (en) | 2004-09-27 | 2008-11-18 | Idc, Llc | Measurement of the dynamic characteristics of interferometric modulators |
| US8124434B2 (en) | 2004-09-27 | 2012-02-28 | Qualcomm Mems Technologies, Inc. | Method and system for packaging a display |
| US7321456B2 (en) | 2004-09-27 | 2008-01-22 | Idc, Llc | Method and device for corner interferometric modulation |
| US7417783B2 (en) * | 2004-09-27 | 2008-08-26 | Idc, Llc | Mirror and mirror layer for optical modulator and method |
| US7289256B2 (en) | 2004-09-27 | 2007-10-30 | Idc, Llc | Electrical characterization of interferometric modulators |
| US7327510B2 (en) | 2004-09-27 | 2008-02-05 | Idc, Llc | Process for modifying offset voltage characteristics of an interferometric modulator |
| US7724993B2 (en) | 2004-09-27 | 2010-05-25 | Qualcomm Mems Technologies, Inc. | MEMS switches with deforming membranes |
| US7302157B2 (en) | 2004-09-27 | 2007-11-27 | Idc, Llc | System and method for multi-level brightness in interferometric modulation |
| TW200628877A (en) | 2005-02-04 | 2006-08-16 | Prime View Int Co Ltd | Method of manufacturing optical interference type color display |
| WO2006121784A1 (en) * | 2005-05-05 | 2006-11-16 | Qualcomm Incorporated, Inc. | Dynamic driver ic and display panel configuration |
| US7948457B2 (en) | 2005-05-05 | 2011-05-24 | Qualcomm Mems Technologies, Inc. | Systems and methods of actuating MEMS display elements |
| US7920136B2 (en) * | 2005-05-05 | 2011-04-05 | Qualcomm Mems Technologies, Inc. | System and method of driving a MEMS display device |
| CN101228093B (en) | 2005-07-22 | 2012-11-28 | 高通Mems科技公司 | MEMS devices having support structures and methods of fabricating the same |
| WO2007013939A1 (en) | 2005-07-22 | 2007-02-01 | Qualcomm Incorporated | Support structure for mems device and methods therefor |
| CN101228091A (en) * | 2005-07-22 | 2008-07-23 | 高通股份有限公司 | Support structure for MEMS device and methods thereof |
| EP2495212A3 (en) | 2005-07-22 | 2012-10-31 | QUALCOMM MEMS Technologies, Inc. | Mems devices having support structures and methods of fabricating the same |
| US7355779B2 (en) | 2005-09-02 | 2008-04-08 | Idc, Llc | Method and system for driving MEMS display elements |
| US7630114B2 (en) | 2005-10-28 | 2009-12-08 | Idc, Llc | Diffusion barrier layer for MEMS devices |
| US8391630B2 (en) | 2005-12-22 | 2013-03-05 | Qualcomm Mems Technologies, Inc. | System and method for power reduction when decompressing video streams for interferometric modulator displays |
| US7795061B2 (en) | 2005-12-29 | 2010-09-14 | Qualcomm Mems Technologies, Inc. | Method of creating MEMS device cavities by a non-etching process |
| US7636151B2 (en) | 2006-01-06 | 2009-12-22 | Qualcomm Mems Technologies, Inc. | System and method for providing residual stress test structures |
| US7916980B2 (en) | 2006-01-13 | 2011-03-29 | Qualcomm Mems Technologies, Inc. | Interconnect structure for MEMS device |
| US7382515B2 (en) | 2006-01-18 | 2008-06-03 | Qualcomm Mems Technologies, Inc. | Silicon-rich silicon nitrides as etch stops in MEMS manufacture |
| US8194056B2 (en) | 2006-02-09 | 2012-06-05 | Qualcomm Mems Technologies Inc. | Method and system for writing data to MEMS display elements |
| US7582952B2 (en) | 2006-02-21 | 2009-09-01 | Qualcomm Mems Technologies, Inc. | Method for providing and removing discharging interconnect for chip-on-glass output leads and structures thereof |
| US7547568B2 (en) | 2006-02-22 | 2009-06-16 | Qualcomm Mems Technologies, Inc. | Electrical conditioning of MEMS device and insulating layer thereof |
| US7550810B2 (en) | 2006-02-23 | 2009-06-23 | Qualcomm Mems Technologies, Inc. | MEMS device having a layer movable at asymmetric rates |
| US7450295B2 (en) | 2006-03-02 | 2008-11-11 | Qualcomm Mems Technologies, Inc. | Methods for producing MEMS with protective coatings using multi-component sacrificial layers |
| US7643203B2 (en) | 2006-04-10 | 2010-01-05 | Qualcomm Mems Technologies, Inc. | Interferometric optical display system with broadband characteristics |
| US7903047B2 (en) | 2006-04-17 | 2011-03-08 | Qualcomm Mems Technologies, Inc. | Mode indicator for interferometric modulator displays |
| US7623287B2 (en) | 2006-04-19 | 2009-11-24 | Qualcomm Mems Technologies, Inc. | Non-planar surface structures and process for microelectromechanical systems |
| US7711239B2 (en) | 2006-04-19 | 2010-05-04 | Qualcomm Mems Technologies, Inc. | Microelectromechanical device and method utilizing nanoparticles |
| US7527996B2 (en) | 2006-04-19 | 2009-05-05 | Qualcomm Mems Technologies, Inc. | Non-planar surface structures and process for microelectromechanical systems |
| US7417784B2 (en) | 2006-04-19 | 2008-08-26 | Qualcomm Mems Technologies, Inc. | Microelectromechanical device and method utilizing a porous surface |
| US8049713B2 (en) | 2006-04-24 | 2011-11-01 | Qualcomm Mems Technologies, Inc. | Power consumption optimized display update |
| US7369292B2 (en) | 2006-05-03 | 2008-05-06 | Qualcomm Mems Technologies, Inc. | Electrode and interconnect materials for MEMS devices |
| US7405863B2 (en) | 2006-06-01 | 2008-07-29 | Qualcomm Mems Technologies, Inc. | Patterning of mechanical layer in MEMS to reduce stresses at supports |
| US7649671B2 (en) | 2006-06-01 | 2010-01-19 | Qualcomm Mems Technologies, Inc. | Analog interferometric modulator device with electrostatic actuation and release |
| US7321457B2 (en) | 2006-06-01 | 2008-01-22 | Qualcomm Incorporated | Process and structure for fabrication of MEMS device having isolated edge posts |
| US7471442B2 (en) * | 2006-06-15 | 2008-12-30 | Qualcomm Mems Technologies, Inc. | Method and apparatus for low range bit depth enhancements for MEMS display architectures |
| US7702192B2 (en) | 2006-06-21 | 2010-04-20 | Qualcomm Mems Technologies, Inc. | Systems and methods for driving MEMS display |
| US7835061B2 (en) | 2006-06-28 | 2010-11-16 | Qualcomm Mems Technologies, Inc. | Support structures for free-standing electromechanical devices |
| US7385744B2 (en) | 2006-06-28 | 2008-06-10 | Qualcomm Mems Technologies, Inc. | Support structure for free-standing MEMS device and methods for forming the same |
| US7777715B2 (en) | 2006-06-29 | 2010-08-17 | Qualcomm Mems Technologies, Inc. | Passive circuits for de-multiplexing display inputs |
| US7527998B2 (en) | 2006-06-30 | 2009-05-05 | Qualcomm Mems Technologies, Inc. | Method of manufacturing MEMS devices providing air gap control |
| US7388704B2 (en) | 2006-06-30 | 2008-06-17 | Qualcomm Mems Technologies, Inc. | Determination of interferometric modulator mirror curvature and airgap variation using digital photographs |
| JP4327183B2 (en) * | 2006-07-31 | 2009-09-09 | 株式会社日立製作所 | High pressure fuel pump control device for internal combustion engine |
| US7763546B2 (en) | 2006-08-02 | 2010-07-27 | Qualcomm Mems Technologies, Inc. | Methods for reducing surface charges during the manufacture of microelectromechanical systems devices |
| US7566664B2 (en) | 2006-08-02 | 2009-07-28 | Qualcomm Mems Technologies, Inc. | Selective etching of MEMS using gaseous halides and reactive co-etchants |
| KR101628340B1 (en) | 2006-10-06 | 2016-06-08 | 퀄컴 엠이엠에스 테크놀로지스, 인크. | Display device, and method of forming display |
| US8872085B2 (en) | 2006-10-06 | 2014-10-28 | Qualcomm Mems Technologies, Inc. | Display device having front illuminator with turning features |
| US7545552B2 (en) | 2006-10-19 | 2009-06-09 | Qualcomm Mems Technologies, Inc. | Sacrificial spacer process and resultant structure for MEMS support structure |
| US7706042B2 (en) | 2006-12-20 | 2010-04-27 | Qualcomm Mems Technologies, Inc. | MEMS device and interconnects for same |
| US7535621B2 (en) | 2006-12-27 | 2009-05-19 | Qualcomm Mems Technologies, Inc. | Aluminum fluoride films for microelectromechanical system applications |
| US7733552B2 (en) | 2007-03-21 | 2010-06-08 | Qualcomm Mems Technologies, Inc | MEMS cavity-coating layers and methods |
| US7719752B2 (en) | 2007-05-11 | 2010-05-18 | Qualcomm Mems Technologies, Inc. | MEMS structures, methods of fabricating MEMS components on separate substrates and assembly of same |
| US7625825B2 (en) * | 2007-06-14 | 2009-12-01 | Qualcomm Mems Technologies, Inc. | Method of patterning mechanical layer for MEMS structures |
| US7569488B2 (en) * | 2007-06-22 | 2009-08-04 | Qualcomm Mems Technologies, Inc. | Methods of making a MEMS device by monitoring a process parameter |
| US8068268B2 (en) | 2007-07-03 | 2011-11-29 | Qualcomm Mems Technologies, Inc. | MEMS devices having improved uniformity and methods for making them |
| US8058549B2 (en) | 2007-10-19 | 2011-11-15 | Qualcomm Mems Technologies, Inc. | Photovoltaic devices with integrated color interferometric film stacks |
| KR20100090257A (en) | 2007-10-19 | 2010-08-13 | 퀄컴 엠이엠스 테크놀로지스, 인크. | Display with integrated photovoltaic device |
| US8068710B2 (en) | 2007-12-07 | 2011-11-29 | Qualcomm Mems Technologies, Inc. | Decoupled holographic film and diffuser |
| US7863079B2 (en) | 2008-02-05 | 2011-01-04 | Qualcomm Mems Technologies, Inc. | Methods of reducing CD loss in a microelectromechanical device |
| US7851239B2 (en) * | 2008-06-05 | 2010-12-14 | Qualcomm Mems Technologies, Inc. | Low temperature amorphous silicon sacrificial layer for controlled adhesion in MEMS devices |
| US7864403B2 (en) * | 2009-03-27 | 2011-01-04 | Qualcomm Mems Technologies, Inc. | Post-release adjustment of interferometric modulator reflectivity |
| US8736590B2 (en) | 2009-03-27 | 2014-05-27 | Qualcomm Mems Technologies, Inc. | Low voltage driver scheme for interferometric modulators |
| CN102834761A (en) | 2010-04-09 | 2012-12-19 | 高通Mems科技公司 | Mechanical layer and methods of forming the same |
| US9134527B2 (en) | 2011-04-04 | 2015-09-15 | Qualcomm Mems Technologies, Inc. | Pixel via and methods of forming the same |
| US8963159B2 (en) | 2011-04-04 | 2015-02-24 | Qualcomm Mems Technologies, Inc. | Pixel via and methods of forming the same |
| US8659816B2 (en) | 2011-04-25 | 2014-02-25 | Qualcomm Mems Technologies, Inc. | Mechanical layer and methods of making the same |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US31498A (en) * | 1861-02-19 | Method of hanging and securing kecipkocating mill-saws | ||
| NL7510103A (en) * | 1975-08-27 | 1977-03-01 | Philips Nv | ELECTROSTATICALLY CONTROLLED IMAGE DISPLAY DEVICE. |
| US4229732A (en) * | 1978-12-11 | 1980-10-21 | International Business Machines Corporation | Micromechanical display logic and array |
| NL8001281A (en) * | 1980-03-04 | 1981-10-01 | Philips Nv | DISPLAY DEVICE. |
-
1982
- 1982-02-01 NL NL8200354A patent/NL8200354A/en not_active Application Discontinuation
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1983
- 1983-01-24 US US06/460,420 patent/US4519676A/en not_active Expired - Fee Related
- 1983-01-26 EP EP83200116A patent/EP0085459B1/en not_active Expired
- 1983-01-26 DE DE8383200116T patent/DE3363454D1/en not_active Expired
- 1983-01-27 CA CA000420370A patent/CA1188780A/en not_active Expired
- 1983-01-28 ES ES519356A patent/ES519356A0/en active Granted
- 1983-02-01 JP JP58013857A patent/JPS58132782A/en active Granted
- 1983-07-14 ES ES524105A patent/ES8404537A1/en not_active Expired
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1987
- 1987-01-08 HK HK49/87A patent/HK4987A/en not_active IP Right Cessation
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| ES8400832A1 (en) | 1983-11-01 |
| EP0085459A3 (en) | 1983-08-17 |
| ES519356A0 (en) | 1983-11-01 |
| HK4987A (en) | 1987-01-16 |
| US4519676A (en) | 1985-05-28 |
| EP0085459A2 (en) | 1983-08-10 |
| JPS58132782A (en) | 1983-08-08 |
| ES524105A0 (en) | 1984-04-16 |
| NL8200354A (en) | 1983-09-01 |
| EP0085459B1 (en) | 1986-05-14 |
| DE3363454D1 (en) | 1986-06-19 |
| JPH0349117B2 (en) | 1991-07-26 |
| ES8404537A1 (en) | 1984-04-16 |
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