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Publication numberUS3813265 A
Publication typeGrant
Publication dateMay 28, 1974
Filing dateMar 23, 1972
Priority dateFeb 16, 1970
Publication numberUS 3813265 A, US 3813265A, US-A-3813265, US3813265 A, US3813265A
InventorsMarks A
Original AssigneeMarks A
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Electro-optical dipolar material
US 3813265 A
Images(5)
Previous page
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Description  (OCR text may contain errors)

May 28, 1974 A. M. MARKS ELECT0-0PTICAL DIPOLAR MATERIAL Original Filed Feb. 16, l970 5 Sheets-Sheet l X DIRECTION OF ELECTRIC VC7DR OF LIGHT:

POL A 2/24 TIOIV AMPLITUDE (JNTFIVSITTMZ) A L WAVELENGTH (coma) rue rum-'5 FUNDAMENTAL Arm/sures OF LIGHT ARE AMPLITUDE, WA VELENGTII, awn Mar/4 4w Paul/W24 r/o/v.

FIG. I

POLAR GRAPH 0F RELATIVE RESPONSE VE5US ANGLE OFA DIPOLE T04 CONSTANT S/GNAL INTENS/TK FIG. 2

cosa t ANGLE POLARIZATION DIRECT/0N DIPOLE ANTENNA RElAT/ VE RESPONSE OFA D/FUL E ANTENNA VERSl/b' FDIAR/Z/l T/O/V 0125c TION gll.

' FIG. 3

y 1974 A. M. MARKS 3,813,265

ELECTRO-OPTICAL DIPOLAR MATERIAL Original Filed Feb. 16. 1970 5 Sheets-Sheet 2 A A [2 DIPOLE HALF wAve DIPOLE w/rn' I. CENTRAL LOAD RESISTOR aa/sm/sursn RESISTANCE SHOWING HAF WA VE DIPOLE WITH-CHARACI'Ek/STIC 0.40 RES/5 TOR TUNED 7'0 ABSORE MAX MUM Pan 0.

F'IG.4

. .swawwc: mar rue EFFECT/V5 c2055 SECTION 0FAN 5 ANTENNA MAY BE MANY 77ME5 fl/e PHYS/CAL cms seer/01v,- nv 71/15 6456 x251. Pan 6P ls FUNNEL 45a FR M AN EFH'cr/ue' 600:! SECTION nvm m: SMALLER ACTLML ceoss seer/01v OF THE ANTENNAE.

POM 2 RAD/4 7'60 0R ABSORBED A WAVE LENGTH May 28, 1974 A. M. MARKS ELECTRO-OPTICAL DIPOLAR MATERIAL Original Filed Feb. 16, 1970 5 Sheets-Sheet 4 A APPLIED ELECTRIC FILO PULSE Y FLU/O OR PLASTIC LAYER Wll/CH 'I-IAAUENS' SUPPORT INCIDENT uaur (RM/DOM) om os "a PEmw A POtAR/ZED rum-M17750 k4) ALUMINUM FLA my POLAR/Z512 FIGBA 8, 1974 A. MARKS 3,813,265

ELECTRO-OPTICAL DIPOLAR MATERIAL Original Filed Feb. 16, 1970 5 Sheets-Sheet-5 United States Patent O 3,813,265 ELECTRO-OPTICAL BIPOLAR MATERIAL Alvin M. Marks, 166-25 9th Ave., Whitestouc, NY. 11357 Application Feb. 16, 1970, Ser. No. 11,696, now Patent No. 3,709,828, which is a continuation-in-part of application Ser. No. 378,836, June 29, 1964, now Patent No. 3,512,876. Divided and this application Mar. 23, 1972, Ser. No. 237,350

Int. Cl. F21v 9/00; G02f 1/18 US. Cl. 117-211 31 Claims ABSTRACT OF THE DISCLOSURE This application is a divisional of Ser. No. 11,-696, filed Feb. 16, 1970, now Pat. No. 3,709,828 which in turn is a continuation-in-part of Ser. No. 378,836, filed June 29, 1964, now -Pat. No. 3,512,876.

This invention relates to conducting dipole polarizers and articles, products, devices, and the like, produced therefrom having preferred optical properties, the conducting dipoles being advantageously formed of metals, nonmetals, or semi-conductive materials capable of forming whiskers by vapor deposition or capable of forming submi-cron rod-like shapes by using metallurgical melting and controlled freezing techniques, growth from a vapor, or other known techniques. The dipoles are suspended in a transparent layer of material capable of being congealed or hardened after the dipoles have been oriented in the desired direction.

RELATED APPLICATION In related application Ser. No. 378,836, methods and apparatus are disclosed for controlling light and related forms of electromagnetic radiation using dipole particles suspension in transparent media. By employing an external electrical or magnetic field, the optical properties of the media can be varied by orienting and disorienting the dipolar particles in suspension in accordance with the field applied, the media being a fluid in which Brownian movement aids in randomizing the dipole particles upon removal of the external field. In its broad aspects, the related application provides a light-controlling device comprising in combination a fluid suspending medium and a plurality of minute dipole particles rotatably carried in the medium the particles advantageously having a long dimension of the order of about \/2n and at least one other dimension preferably not exceeding about x1011 (where A is the wavelength of light and n is the index of refraction of the suspending medium). The'disposition of the particles in the medium is controlled by applying an electric, magnetic or mechanical shear force field to the suspension. One example of a light-controlling device is an electro-optical ,ldfififi Patented May 28, 197% shutter. The related application goes into great detail in the technical aspects of dipole particles, which disclosure is wholly incorporated into this application by reference.

BACKGROUND OF THE INVENTION In the prior art, it is known to produce metal polarizers by the reduction of metal salts in stretched polymers, such as cellulose hydrate, gelatin, polyvinyl alcohol, and the like. The metals so reduced form aggregates within the interstices of the polymer. Such aggregates are usually relatively uncontrolled as to length and diameter. Since most polymers have disordered regions, irregularly shaped metal deposits were often formed which detracted from the transmittance and polarization characteristics. The polymers employed, were capable of-swelling or dissolving in water, and were generally sensitive to ambient atmospheric conditions.

Elongated silver particles having a maximum ratio of 3 to 1 in the form of ellipsoid of silver, have been produced in glass by strong stretching. For a given mass per unit area of absorbent material, the absorption obtained by such particles is greater than that of an ordinary colorant, such as cobalt dissolved in the glass, by a factor of about 3000 to 1.

The prior art methods of stretching to deform particles do not enable control of particle ratio of length/width, nor do they result in optimum length/width ratios required for strong polarization.

Another polarizer described in the prior art consists of minute wires or conductors on a glass surface or within a glass structure. However, no practical means for the production of such structures have been disclosed. Very long thin conductors are not as efiicient for producing a high degree of polarization and transmittance in a specifiic wavelength range. The dipoles herein disclosed may be fabricated by incorporation into a suitable stable polymer or a glass melt and aligned by mechanical shear forces, or an electric or magnetic field. It would be desirable to have a dipole particle which is inert and which will resist degradation during use in the ambient environment.

OBJECTS OF THE INVENTION It is an object of the invention to provide conductive and semi-conductive dipole particles which are substan tially inert to the ambient environment and which resist degradation.

Another object is to provide as an article of manufac= ture a transparent material, such as a solid material made of glass or transparent plastic, characterized by a disper= sion of microscopic, inert, dipole particles oriented to confer light polarizing properties on the material.

A further object is to provide a solid transparent substrate having a transparent coating thereon containing a. dispersion of submicron, inert, conductive, dipole particles having a preferred orientation, whereby to provide pre determined optical properties to the coated substrate.

A still further object is to provide a composition of matter for optical use, said composition comprising a suspending medium containing a plurality of dipole parti cles, the medium being one capable of being converted to the fluid or soft state to enable orientation of the particles and capable of being solidified to permanently fix the position of oriented dipole particles.

The invention also provides as an object a method of producing dipole particles of relatively controlled sizes.

These and other objects will more clearly appear when taken in conjunction with the disclosure and with the accompanying figures of the drawing which are summarized as follows.

In the drawing:

FIG. 1 illustrates the three fundamental attributes of light;

FIG. 2 is a polar graph showing relative response versus the angle of a dipole to a constant signal intensity;

FIG. 3 shows the relative response of a dipole antenna versus polarization direction;

FIG. 4 depicts a half-wave dipole with a characteristic load resistor tuned to absorb maximum power;

FIG. 5 illustrates diagrammatically the effective cross section of a dipole antenna as compared to the actual physical cross section;

FIG. 6 is a graph showing the relative power absorbed or re-radiatedas a function of the wavelength of light for thick and thin half-wave dipoles;

FIG. 7 depicts a transparent substrate, e.g. glass or plastic, having a transparent coating, e.g. of plastic, in which dipoles are dispersed and oriented normal to the surface of the coating;

FIG. 8 is similar to FIG. 7 except that the dipole particles are oriented parallel to the surface to provide polarization effects, whether the coated article is a lens, a coated windshield for automobiles, coated sheet material, and so forth; and FIG. 8A shows flake orientation;

FIG. 9 is similar to FIGS. 7 and 8 except that the dipoles in the coating are randomly oriented;

FIG. 10 is a diagrammatic cross sectional view of a machine for the continuous production of polarizing film or sheet utilizing dipoles which are electrically aligned;

FIG. 11 is a detailed fragment of the electrical aligning section of the device of FIG. 10; and

FIG. 12 is a vertical cross section of a high pressure spin coating device for producing high field orientation dipole suspension coatings.

GENERAL STATEMENT OF THE INVENTION The present invention overcomes the deficiencies of the prior art by providing metal whisker dipoles or submicron rod-like dipoles of relatively inert material such as chromium, aluminum nickelide, platinum or other conducting metal; or alternatively, by utilizing semi-conductors which are advantageous for certain other characteristics, such as silicon, germanium, or zinc sulfide whiskers, and having a selected length, and length to width ranges.

These are preferentially incorporated in a readily meltable glass, thermoplastic or plastic solution, and oriented by means well known to the art, such as by the application of an electrical or magnetic field or by the application of stretching where differential shear is produced during stretch causing the parallel orientation of the particles, and subsequently solidified by cooling or evaporation of solvent.

Thus, as one broad aspect of the invention, a composition of matter is provided for optical use comprising a plurality of conductive or semi-conductive asymmetric particles (e.g. dipoles) suspended in a transparent medium which is substantially a solid at ambient temperatures but which can be melted or softened to a fluid state at an elevated temperature to form any desired shape, the particles being then oriented to a preferred direction by an electrical or magnetic field before allowing the shaped body to solidify.

Another aspect of the invention resides in an article of manufacture in the form of a polarizer comprising a layer of transparent material having a dispersion of inert conductive or semi-conductive dipole particles therein having a length of \/2ni50%, and preferably having an average diameter of at least about lOn, where n equals the index of refraction of the transparent medium, the

long axis of particles being oriented in the plane of the transparent medium.

The dipole particles can be produced by various methods. Thus, metal dipoles can be produced by vapor deposition in a partial vacuum to produce metal whiskers which can be sized in a blender and the sizes separated by centrifuging or by differential settling.

Another method is to produce a eutectic of a binary alloy which, by directional freezing, produces a rod-like structure, the size of the rod-like structure being determined by the velocity of the plane of solidification and temperature gradient. After selectively dissolving away the matrix metal, the residue of rod-like material is washed and then suspended in an inert liquid for sizing in a blender, the sized material being thereafter selectively separated using differential settling or centrifuging techniques. The foregoing and other methods will be described in more detail hereinafter.

The dipole particles useful in the present invention are characterized in that they have at least one dimension large relative to at least one other dimension, that is to say, they are in the form of flakes, needles or the like. The dipole particles should have at least one dimension equal to one-half of the wavelength of the radiation to be controlled (normally, visible light, but in some cases, infrared, ultraviolet, microwave, or other portions of the electromagnetic spectrum) and at least one other dimension substantially smaller than one-half of said wavelength. The magnitude of the third dimension, that is, whether the particle is a needle or a flake, depends on the requirements of the specific embodiment of the invention, as more fully discussed below.

For purposes of brevity, the term light is used throughout the present specification and claims in a generic sense and is intended to encompass not only visible light but also infrared and ultraviolet light," as well as microwave radiation in the neighboring portions of the electromagnetic spectrum.

In addition to the dimensional requirements herein disclosed, the electrical or magnetic properties of the dipolar particles, i.e. the conductivity, should be such as to facilitate orientation in an electric or magnetic field, and strong interaction with electromagnetic radiation.

The suspending medium is a fluid, non-reactive with the dipole particles, or is a substance capable of being converted to a fluid, at a temperature sufficiently low to avoid any adverse effect on the dipole particles.

It is not in all cases necessary that the suspending medium be in the liquid state during the first stage of orienting the particles. Providing the applied torque is sufficiently strong to orient the dipole particles against a certain amount of plastic resistance of the suspending medium, it is sufficient if the suspending medium is in a highly deformable plastic state. The term fluid as used herein should therefore be understood to encompass such a plastic or soft condition. For most applications of the present invention, the suspending medium is present as a liquid during alignment or disorientation of the dipole particles. The dipole particles must also be of such a nature that they are capable of being oriented by an applied electric, magnetic or, in certain cases, a mechanical shear force field.

Some particles have an inherent dipole moment by reason of their internal structure in which the effective center of positive charge in the molecule or crystal is spaced from the center of positive charge. Such an inherent dipolar character, if present, is effective to some degree in augmenting the tendency of the particles to orient themselves in an applied force field. Inherent dipolarity is, however, neither essential nor a major factor in determining the effectiveness of the dipole particles.

As stated hereinbefore, the preferred dimensions of the particles above referred to may be characterized by A/Zn where k is the wavelength of the light to be polarized and n is the index of refraction of the medium in which the particles are suspended and oriented.

For example, if a suspension of dipole particles is to polarize light at 5600 A., and the index of refraction of the transparent suspending medium is 1.5, the optimum length for the dipole whisker is 5600/2X l.5=(5600/3)=1860 A.

The length to diameter ratio should be not less than 3, and preferably greater; that is, from to 100. The percentage of polarization increases with the length/width ratio, and the width of absorption or reflectance band decreases. Where dipole particles are highly conducting, such as with silver, gold or copper whiskers, the polarizer acts as a beam splitter, and the radiation is partly transmitted and partly reflected. The transmitted radiation is polarized with good image resolution. The re flected radiation, however, is scattered, and polarized in a plane at 90 to that of the plane of polarization of the transmitted light.

A beam splitting polarizer of this type is particularly useful where polarization of intense light beam sources is required. In the case of the absorption polarizer, the temperature of the polarizing element rises perhaps to cause destruction. However, with the beam splitting polarizer, the radiation is mostly reflected and transmitted, and the temperature rise is minimized.

The most efiicient sheet polarizer is that which requires the smallest number of particles per unit area to accomplish a given percent polarization. The most efiicient sheet polarizer is obtained by selecting particles within a narrow size range, about the optimum )./2n dimension. For example, for most efi'icient polarization in the range from 4500 A. to 6600 A., dipole particles having length ranges between 1500 A. to 2200 A., are selected. For a still narrower range of polarizing characteristics, then a still narrower range of dipole particle lengths is employed. For example, for a narrow frequency band which might characterize a laser, then a single length with close tolerances is employed.

Stable chemical structures are relatively rare. Most chemical structures are relatively easily deteriorated by ultraviolet, visible and infrared light, heat and chemical action.

Light is an electromagnetic wave having three fundamental attributes, which are: amplitude or intensity, wavelength or color; and polarization or the vibration direction at right angles to the ray.

These three fundamental attributes of light are shown in FIG. 1.

A half-wave dipole antenna, which is normally used for television reception, has interesting properties.

The half-wave dipole is capable of controlling all three attributes of light, by varying its length, thickness, resistivity and angular position.

The electric power absorbed from the radiation by the half-wave dipole depends upon two orientation angles of the dipole. The first angle, 0, is that between the length of the dipole and the signal path. The second angle, 11 is that between the length of the dipole and the direction of polarization of the signal.

FIG. 2 shows a polar graph of radiant power absorbed versus angle 0.

In FIG. 3, the radiation ray path is normal to the plane of the diagram, and there is shown the angle versus the power absorbed by the dipole.

A maximum response is obtained when the antenna is aligned parallel to the polarized electric vector of the radiation and at right angles to the signal path (4 =0, and 0:90"). The antenna absorbs no power when it is placed at right angles to the polarized electric vector of the radiation; or arranged parallel to the ray path.

When adjusted for a maximum response, a half-wave or M2 antenna is then said to become resonant to the particular wavelength )t.

The power absorbed by the dipole from the radiant energy may be re-radiated, or absorbed and dissipated as heat, depending on the electrical resistance of the halfwave dipole antenna.

If power is to be absorbed from the dipole antenna and utilized in an outside electric circuit, as for example in a television set, a matched or characteristic resistance of 73 ohms must be inserted at its center of the halfwave dipole antenna, as shown in FIG. 4.

An antenna may be made of such material, thickness and length as to achieve full power absorption, or nearly total reflection.

In FIG. 4, there is also shown a half-wave (M2) antenna 2; in which the central resistor is replaced with a single rod having a distributed resistance of approximately ohms, which results in the absorption of radiation in the wavelength range 7\.

Now, if instead of a half-wave antenna with a central resistor or an equivalent distributed resistance, a halfwave antenna of low resistance is employed, then the half-wave dipole antenna becomes reflective for the full wavelength. The radiant power may be said to be absorbed by the half-wave dipole and then re-radiated in all directions, with the intensity direction pattern shown in FIG. 2. Thus, the resistivity characteristics of the materials, together with the length and width, controls the distributed resistance of the half-wave antenna. These factors may be adjusted so that the half-wave dipole antenna has high absorptivity or high reflectivity for incident radiation of a given wavelength band.

FIG. 5 shows another very important property of the half-wave dipole antenna, the effective cross section.

FIG. 5 shows a half-wave dipole antenna having a thickness of its length. Its length is M2 and its thickness M50. The physical cross section of this half-wave dipole at right angles to the light ray is:

(M2) (ll/50) /l00.

However, it is known that the elfective cross section of a half-wave dipole antenna is much larger. The cross section from which the half-wave dipole appears to absorb power is approximately )3/ 8. A rectangle of this size is shown in dotted lines surrounding the antenna rod, the radiant power actually tunnelling into the dipole. In this example, the effective area of the antenna has been increased by a factor of A /8 divided by V/ or 12.5 times.

Dipole antennas have been employed for the electromagnetic spectrum all the way from long wave radio down through the television range into the microwave and millimeter wave spectrum.

Dipoles have been observed which are resonant in the range of the wavelength of visible light. Yellow light at the peak sensitivity of the human eye has a wavelength of 0.565 microns (yellow). Elongated metal rods of submicron dimensions in colloidal suspension in a transparent medium, results in myriads of light-responsive dipoles. The transparent medium keeps the dipoles in spaced relation.

The index of refraction n of a given medium may be defined as the ratio of the speed of light in free space, to the speed of light in the medium. Since the speed of light in all substances is less than in free space, n is always greater than I. The wavelength of light in a given medium is inversely proportional to the index of refraction n of the medium.

Because the index of refraction of transparent media is approximately 1.5, the dimensions of a halfwave dipole must be decreased in inverse proportion; that is, for n==l.5, the actual resonant length of a half-wave dipole in such a medium becomes /z))\/l.5= \/3.

For example, in a medium having an index of retrac 7 (0.565/3)=0.l88 microns (or 1880 A.) of yellow light for 0.565 microns wavelength (or 5650 A.).

The 7\/ 3 dimension, of course, is correct only for n=1.5 and will vary with the index of refraction of the medium.

Another interesting property of the dipole is that the sharpness of its tuning, or the wavelength range over which it will absorb or reflect, depends on the ratio of the length to the thickness of the dipole, as well as on the resistivity of the dipole material.

FIG. 6 refers to the reflection or absorption of radiant energy by a half-wave antenna showing the relative power absorbed or re-radiated, versus the ratio of length to thickness of the antennae.

(A) For thin dipole antenna (25/1) (B) For a thick dipole antenna 1) We now come to the application of these basic concepts to light control; that is, control of all three basic attributes of light, intensity, color and polarization, by dipoles in suspensions in a transparent medium.

Pigments formed from dipolar materials are visually indestructable. The polarization, reflectivity or absorptivity characteristics of the dipole suspensions are predetermined by the appropriate selection of length, width and resistivity of the dipoles, together with their concentration and orientation.

Such a dipole suspension has the property of absorbing or reflecting specified wavelength ranges. Since a specific resonance characteristic is obtainable from the same material merely by changing its length to width ratio, very pure colors can be obtained by transmission or reflection from coatings formed from such suspensions. When oriented, the dipole suspension has strong polarizing properties.

The substances chosen to form the dipoles are preferably chemically stable materials, which remain permanently within the suspension, and which are not subject to chemical destruction by ordinary atmospheric agents or by exposure to light. However, dichroic crystalline needles, such as herapathite dipoles, may be employed as dipoles.

The dipoles may be formed of metals, such as gold, platinum, palladium, chromium, tin, or metal compounds such as Al Ni, and the like, which are known to grow submicron crystal-whiskers, under appropriate conditions, such as from the vapor phase. Semi-metals, such as carbon, silicon and germanium, are also known to form crystal-whiskers. These crystal-whiskers may then be incorporated in a fluid to form a dipole suspension.

A crystal-whisker made of a single substance of the utmost permanence, may be predetermined in its properties; a perfect black, a perfect white diffuse reflector, or having sharp absorptivity or reflectivity bands in the yellow, green, blue or other regions of the spectrum. When oriented, these result in polarizing these characteristics.

The effective cross section per particle oriented normal to center distance between the longitudinal axis of the light in a medium of index of refraction n is:

This property is useful in calculating the number of particles required for substantially complete light adsorption or reflection as follows:

Assuming no aggregation of particles, the concentration of a suspension of submicron dipolar particles per square centimeter in a medium having an index of refraction of 1.5 is determined as follows:

=6.25 10 particles/cm It is possible to obtain the interparticle spacing between dipoles oriented in the same direction, the inter-particle spacing for substantially parallel dipoles being the center to center distance between the longitudinal axis of the particles taken at right angles to each other. The interparticle spacing for substantially complete light absorption or reflection does not substantially exceed the width of the eflective cross section.

The derivation of the interparticle spacing, d for the polarizing case is determined when: the dipoles are all parallel and disposed in the plane of the sheet. The details are disclosed in copending application Ser. No. 378,836, filed June 29, 1964, and need not be repeated here. Simply stated, the interparticle spacing may be determined as follows:

N =the number of dipoles per unit volume of suspension V =volume of cube occupied by one dipole=1/N d =interparticle spacing=3 V =3 1/ N (3) The concentration of dipole particles required to provide effective surface coverage is generally very low as will be apparent from the following:

Assuming a square cross section for the particle having a width a, the mass per particle is where b=width (a) to length ratio and 6=density in gms./cm. of the dipole.

Thus, the mass m,, per dipole particle of gold for length to width ratio of 25 where 6 of gold equals 19 and b=l/ 25 is:

m =l9(0.565 10- /3) /25 m of gold=2 10- gms./particle.

The mass m of dipoles per unit area is then determined as follows:

Thus, (A/n)b (particles/cm?) (mass/particle) or 6.25X l0 2X 10*: 1.25 X 10' gms./cm.

As will be noted, very small concentrations of dipole particles of the order of about 2 micrograms/cm. are suflicient to provide effective surface coverage.

For a film of 10* cm. (0.4 mil) thickness, and density=1 gm./cm. this corresponds to a dipole concentration of only 0.125% of the solid film.

Because their effective cross section is much greater than the physical cross section, the dipolar particles may be very sparely distributed in space. The dipolar particles are sufliciently far apart from each other so as to have no physical interaction. Each dipolar particle acts independently of the other.

FIG. 7 shows a film containing dipole particles with their length oriented normal to the surface. The film is transparent because the cross section particles present to the radiation is so small that substantially no light scatter and no light absorption occurs.

FIG. 8 shows a film in the XY plane in which the dipole particles are aligned in the OX direction. Light transmitted along the Z axis into the surface emerges from the other side plane polarized with the electric vector B in the ZY plane. Reflected light in plane polarized with the electric rector E in the ZX plane. Reflected light is polarized and scattered.

FIG. 9 shows a film having dipolar particles in random orientation. Reflected light is symmetrically scattered in all directions. The transmitted light and the reflected light show no polarization. However, since the dipoles are tuned to a particular wave band, the transmitted and reflected rays are complementary in color. Consequently,

in the random orientation, the dipoles act as pigments. However, these dipolar pigments are subject to control by variation of physical quantities of dimension resistivity and orientation.

As stated hereinabove, dipoles may be oriented by an electric field, a magnetic field (if the particle is magnetic, diamagnetic or paramagnetic) or by viscous shear forces in the suspending fluid. Dipole particles tend to disorient rapidly in suspending fluids of low viscosity. For low viscosity fluids obtained by heating to a fluid temperature, the disorientation of dipolar particles may occur in milliseconds. The disorientation is due to Brownian movement or the random impact of the fluid molecules on the dipole particle.

However, if the suspending fluid viscosity is high, dipole orientation will persist for a longer time, from seconds to hours. A permanent orientation of dipolar particles may be achieved in a fluid by allowing the solvent, in the case of a plastic composition, to evaporate while maintaining the orientation.

Metallurgical techniques may be employed to produce dipoles. A known eutectic method for the manufacture of metal dipoles has produced chromium rods and aluminum nickelide rods having a length/Width ratio of about 100, in a range of diameters from 50 A. to 300 A., and lengths to about 40,000 A. The method involves the precipitation of one metal dissolved in another; for example, chromium precipitated from a chromium-copper melt, using a travelling temperature diiferential, or directional cooling from one end of a melt. The solidification rate may vary from about 0.1 to cm./sec. at a temperature gradient of about 1 to 100 C./cm. Subsequently, the copper is dissolved in acid, leaving long thin chromium metal rods having a submicron diameter, and of various lengths. After the extraction of the metal rods, they can be further decreased in size using acid of controlled concentration. Thus, where the diameter is 500 to 1000 A., acid treatment can further decrease the diameter.

It has been found that long rods may be chopped into shorter lengths in a suitable range by the following procedure. The metal rods are suspended in an inert fluid. The fluid may comprise water, alcohol, or an ester with or without dissolved polymer. The polymer helps to suspend these particles. The suspension is placed in a high speed blender, the revolving metal blades of which causes strong shear and impact forces to occur. Most of the cut rods do not appear to be bent but appear to be cleanly sheared into shorter straight rods.

It is theorized that the particles are cut by high speed impact or possibly torn asunder by opposing turbulent shear forces. Whatever the physical explanation may be, the rod lengths varying from about 700 A. up to the maximum particle length are placed in suspension. The particles are then separated into size ranges by fractional centrifugation or by electrophoresis. The larger particles, in the case of centrifugation, are thrown down as the first centrifugate and then successively smaller ranges of particles are thrown down into the centrifugate. Finally, there remains only smaller particles of irregular shape of a very small length/ width ratio. A suitable intermediate ratio range is selected and the process may be repeated, using a smaller viscosity fluid if required, to get a narrower range of ratios. These particles are then filtered and washed with solvent and vacuum dried.

Where glass is used as the final matrix, the selected dipole rods are then mixed with finely powdered glass frits, of a suitable composition well known in the art. This mix is melted, stirred, debubbled, and cast to form sheets. These sheets, when heated to a high viscosity, may be drawn by stretching to orient the dipolar particles. Alternatively, the sheets may be melted or softened at high temperatures to a low viscosity, and the dipole rods oriented by electrical means. To produce a light polarizing sheet, the orientation is carried out to position the dipoles parallel to the surface.

To produce a uniaxial polarizer of the type described in my U.S. Pats. Nos. 3,205,775 and 3,350,982, the dipole rods are oriented normal to the surface of the sheet. To obtain a wedge-shaped transmission pattern requires a combination of two sheets in which the dipole rods are oriented respectively parallel to, and normal to the surface; that is, a combination of uniaxial and linear polarizing sheets.

Various techniques known in the art of glass making may be employed. For example, continuous drawing methods may be employed using a glass melt containing dipoles, and the drawing and rolling of the glass will cause the orientation of the dipolar particles to produce polarized glass. Various selected size ranges may be employed to produce sharp absorption and reflection. bands.

To polarize the entire visible spectrum, selected length ranges of dipole rods varying in length from about 1000 A. to 2500 A. may be employed. To produce glasses which will polarize the infrared, larger particles are employed from about 2100 A. up to about 10,000 A. in length to polarize infrared in the range of 1 to 30 microns. Thus, broadly speaking, the length of the dipoles may range from 1000 A. to 10,000 A., the ultimate size being determined by the particular end use.

Polarizers may also be made by incorporating these dipolar rods in the same selected size ranges in polymers normally employed for polarizing materials; i.e. polyvinyl alcohol, polyvinyl butyral, and these subjected to mechanical elongation to orient the particles in a manner well known in the art.

Another method which may be employed advantageously is the incorporation of the particles in a polymer solution, such as a silicone polymer solution, which has a high degree of stability at an elevated temperature. This solution may be employed by flowing or spinning a coat-= ing onto a glass surface, for example, a lens, which is subjected to an electrical field just before it dries, while the dipoles are free to turn. The dipole rods may be oriented with their long axes parallel to the surface by applying an electrical field parallel to the surface or the dipoles may be oriented normal to the surface by the application of an electrical field normal to the surface.

The polymeric coating containing the dipoles is set by allowing the fluid to evaporate. The dipoles may be placed in a monomer and oriented by electrical fields while the monomer is setting. Alternatively, the monomer may be stretched when partially polymerized to orient the particles by mechanical shear forces and then final ly set by completing the curing process.

As illustrative of the various methods which may be employed in producing conductive dipoles, the following examples are given:

EXAMPLE 1 Flake dipole suspensions EXAMPLE 2 Ultrathin aluminum flake suspensions A novel method of preparing ultrathin aluminum flake suspensions uses aluminum flakes 1-17 microns in diameter, and 0.1 to 1 micron in thickness as the starting point. A suspension is prepared by adding 48 grams of the aluminum flake material to 300 cubic centimeters of di-iso-octyl adipate. This mixture is then shaken and poured into a 500 cubic centimeter graduated cylinder and allowed to settle. Most of the aluminum flakes then settle to the bottom of the graduate. However, a small portion of the flakes remains suspended in a thin layer at the top of the graduate. This top layer then comprises ultrathin aluminum flakes, approximately 0.1 micron 1n thickness, which are then recovered.

Thus, by means of this flotation method, the 0.1 micron thickness flakes are separated from the thicker flakes. These ultrathin flakes may be further separated and concentrated by centrifuging.

Another way to make thin flakes of aluminum or the like is to coat a thin rubber sheet with a film of aluminum by exposing it to aluminum vapor, until a film of approximately 0.01 micron thickness has been built up. This sheet is then stretched to break up the surface into flakes of aluminum. The underlying rubber sheet is next dissolved in order to place the flakes in suspension. Finally, the large flakes are eliminated, and the small flakes in the desired size range are concentrated, by centrifugation. This technique can also be employed using polyvinyl alcohol or polyvinyl chloride sheets by heating the sheets after the coating step, to facilitate their being stretched.

The resulting suspension is suited for use in those embodiments of the invention which require a suspension of dipoles in the form of flakes, for example, the reflectiveabsorptive devices, discussed in the referenced copending application.

EXAMPLE 3 Needle-like metal dipole suspensions For the production of a metal rod dipole particle, a convenient method is to dissolve a metal salt in a matrix of polyvinyl alcohol, cast the solution as a polyvinyl alcohol film, soften and stretch the film in known manner, reduce the metal salt to the metal by exposure of the film to a reducing liquid or gas, and finally dissolve the polyvinyl alcohol in a suitable solvent, thereby providing a suspension of metal rods.

Another convenient method of manufacturing minute metallic dipole particles is to employ a soluble thread having a diameter in the submicron range, and deposit a film of aluminum on the thread by passing the thread through a zone or chamber in which it is exposed to aluminum vapor. The thread is then wound on a spool, and sliced with a microtome. Finally, the supporting thread is dissolved in a suitable solvent, leaving the metal coating in the form of thin aluminum strips in colloidal suspension.

EXAMPLE 4 Needle-like metal dipoles from whiskers Needle-shaped metallic dipoles may be formed from a metal, such as gold, platinum, palladium, chromium, tin or the like, which are known to grow submicrondiameter crystal whiskers under appropriate conditions, usually from the vapor phase. These crystal Whiskers may then be incorporated into fluid to form a dipole suspension. Such needles, if classified to a uniform length, may be made sharply selective as to the wavelengths of light affected by them. This property results from their large length-to-thickness ratio and resistivity, for reasons which are explained below. Such materials constitute a new class of pigments different in effectiveness and mode of operation from conventional pigments.

The factors controlling the growth of needle-like whisker dipoles are partial pressure and temperature of the metal vapor, temperature and nature of the deposition surface, and time of growth. Usually, the growth occurs best under vacuum, or inert gas such as helium or nitrogen, but, in some cases, as with gold, whiskers can be grown in air. Two gold sheets separated by a few millimeters and by a few degrees temperature difference, held in air at a temperature such as to generate an appreciable gold partial vapor pressure, will cause gold whisker crystals to grow normal to the surface of the cooler gold sheet. The dimensions of the whiskers are such as to fall within the size ranges herein specified. On cooling, the whiskers may be incorporated in a plastic film formed by coating the surface of the gold sheet, encompassing the whiskers. Upon drying, the film may be stripped away and dissolved, leaving the gold dipoles in suspension in the fluid. This process may be performed continuously using an endless belt of a material, such as stainless steel, which is initially provided with active sites for initiation of whisker growth.

EXAMPLE 5 Flat crystals Flakes made from crystalline material, such as lead carbonate (pearlescence), may be grown to any desired size by methods well known to the art. These flakes have an index of refraction of about 2.4, and, when placed in a fluid having an index of refraction of about 1.5, are readily aligned by an electric field, and in the equivalent of about 15-20 layers almost totally reflect visible ultraviolet and near infrared radiation, when disoriented or oriented in the plane of the cell wall or sheet; while being almost completely transparent when aligned normal to the sheet surface.

Zinc vapor will deposit submicron flat crystals on a substrate, which can be dissolved away as above described, to yield a metal flake suspension having dipolar characteristics.

Graphite forms flat hexagon flakes which, when suspended in a fluid of low viscosity, show dipolar characteristics.

EXAMPLE 6 Metal coated preformed dipoles Preformed rods of Boehmite (colloidal alumina) are metal-coated by vapor deposition. The Boehmite is in the form of minute crystalline rods or fibrils having a length of approximately 1000 A. and a width of about 5 A. In metal coating the fibrils, the Boehmite crystal rods are heated to various elevated temperatures while exposed to the metal vapor.

Another method is to coat Boehmite particles by chemical deposition. For example, Boehmite particles may be soaked in a solution of a metal halide or nitrate, such as gold chloride, gold nitrate or silver nitrate. The particles are washed to remove all but the adsorbed salt. The Boehmite powder is then heated to a temperature of about 300 C. to decompose the adsorbed salt and thus produce a coating of silver or gold metal on the Boehmite.

EXAMPLE 7 Production of dipoles from binary eutectics Metal fibers can be prepared by the unidirectional so-= lidification of binary eutectic alloy. A well-known example is the system Al-Al Ni. The alloy containing about 5.7% to 6.4% by weight of nickel and the balance aluminum is produced by melting together high purity aluminum (99.99%) and high purity nickel (99.99% The melts are unidirectionally solidified using induction and resistance heating sources by maintaining a thermal gradient during cooling. Whiskers or rods of Al Ni are formed lying parallel to each other in the direction of solidification and dispersed through an aluminum matrix. By increasing the rate of cooling, the diameter of the needles or rods can be increased. The Al Ni whiskers may be extracted from the aluminum matrix by using a 3% solution of aqueous HCl solution. As soon as the whiskers are dislodged, they are removed rapidly from solution and are washed. The whiskers can be graded according to size by differential settling or differential centrifuga- 13 tion as described hereinbefore. Splat cooling may be employed by striking metal droplets against a cold surface of high heat conductivity.

Examples of other eutectic alloys are the following:

TABLE 1 System Eutectic comp. Matrix Fibers A -B1 Bi-2.57 Ag B1 A -0.sa Bi ag-oa A -nai Ca CBABI AS A -Pb Pb-4.77 A Pb A -0.8 Pb

Agar- Agl2% Sr stag. x5

G8-6.5% Al Ga A1 Al-Sn Sn-2.2% Al Sn Al Au-Be Au-20% Be BeAm Au Au-a All-13.2% Ca CaAur Au Au-Na Au-17% Na NaAu, Au

Au-Sb Au-34% Sb AuSb; Au-0.64=% Sb Au-Te Te-47% Au Au'Ie; Au

Au-Tl Tl-27.7% Au Tl Au Au-U. All-12.5% U UAu; Au

Atomic percent.

As will be noted, the fibers contain substantially one metal, that is, some of the compositions yield fibers which at worst contain less than 1% of the second metal. Of the thirteen systems listed, five may yield fibers of pure or nearly pure metal in a matrix of a second pure metal, such as Ag-Bi, Ag-Pb, Al-Ga, Al-Sn and Au-Tl. There are other systems, among which is included the system Cu-Cr.

The resistivities of some of the metals are given as follows:

TABLE 2 Resistivities of metals Resistivity Element: ohm-cm. X 10" at 20 C. Aluminum 2.62 Antimony 39.0 Cadmium 7.5 Chromium 2.6 Copper 1.69 Gold 2.4 Indium 9.0 Iron 10.0 Lead 21.9 Palladium 10.8 Silver 1.62 Tantalum 13.1 Thallium 18.1 Titanium 3.0 Zinc 6.0

Utilizing the known resistivities of the foregoing metals, the length to width ratios of absorbing and reflecting dipoles can be calculated using equation (57) of parent application Ser. No. 378,836 referred to hereinabove. These calculations are summarized in Table 3 which sets forth the length to width ratios for absorbing and reflecting dipoles utilizing specified metals.

TABLE 3.LENGTH '10 WIDTH RATIOS 0F METALLIC DIPOLEB Absorbing Reflecting Metal dipole dipole Aluminum 23.9 7.6 Antimony 6. 2 2. 0 Cadmium. 14. 2 4. 5 Chromium 24.1 7.6 Copper. 29. 2 9. 5 old. 25.1 7.0 Indium- 12. 9 4. l Ir0n 12.3 3.9 Lead. 8.3 2.6 Palladiu 11. 8 8. 7 Silver. 30. 5 9. 6 Tantalum 10. 7 3. 4 Thallium 9.1 2.9 Titanium 22. 4 7. 1 nc 15.9 5.0

In constructing Table 3, the ideal absorbing dipole is assumed tohave a distributed R of about ohms and the ideal reflecting dipole is assumed to have a distributed resistance R of 8 ohms. Values of 1.5 for n and 0.5 microns for). were used.

Thus, the properties of the metal dipoles can be determined beforehand, depending upon the length to Width ratio and those sizes selected in accordance with the particular property desired.

Having graded the sizes of the metal dipoles, these can then be used to make a wide range of products. In this connection,'; reference is made to FIGS. 10 and 11 as illustrative of forming polarizer material in sheet form.

In FIG. 10, there is shown a supply roll 1 and a wind up roll 2 for a thin film substrate or web 3 of plastic material, such as cellulose acetate, cellulose acetate butyrate, acrylic, vinyl film or the like, having a thiclo ness, for example of 0.1 to 1 mm. Film 3 passes over roller 4 where it is coated by a polymer solution 5 containing dipoles. The level 6 of thepolymer solution is maintained by the feed 7, from a level sensing device such as an inverted bottle (not shown). Evaporation of solvents from the coating is initially prevented by means of the shield 8. The dipole coating layer 9 shown in FIG. 11 remains liquid for a time suflicient to enable orientation of the dipble particles 10 by an electrical field 11. An electric field parallel to the surface of the coating is maintained between a plurality of electrodes 12, 13, 14, 15, 16, etc. in the vicinity of the coating 9. To minimize the eifect of the vertical component of the electric field near the electrodes, cool air may be provided in the areas 20 and 21 by ducts 22 and 23 (FIG. 11). This decreases the temperature, and increases the viscosity, of the coating layer 9 thereby preventing the dipoles from being disoriented by the vertical field component. In a similar manner, heated air may be provided in the areas 25 and 26 by the ducts 27 and 28 to decrease the viscosity of the coating 9 where the component of the electric field is most nearly parallel to the surface of the film. This enables the dipoles 10 to be aligned parallel to the surface of the coating 9. The dipoles are fixed by passing the film 3 through the evaporation chamber 30 (FIG. 10) which is provided with the input air duct 31 and the output air duct 32 containing the evaporated solvent. The duct 31 may contain a number of sections. Section 33 may be at a low temperature to freeze the particles into alignment initially while evaporation is occurring. Section 34 may be at ambient temperature to continue the evaporation of solvent and section 35 may be at a higher temperature to evaporate the residual solvent. The film emerging from section 35 over roll 36 is dry. 1

If an herapathite dipolar suspension is employed, the electric field 11 is preferably AC field having a frequency of 10 to IOOkHz. at an electric field intensity of 1 to 20 lcv/cm. The best alignment is obtained at the greatest electric field intensity which is just under the electric breakdown strength of air. Greater electric field strengths may be employed if the entire device is pressurized to several atmospheres.

With metal dipoles in a nonionic fluid, DC or low frequency AC may be employed, in the same electric field strength range. I

The herapathite composition which may be employed contains submicron selected particles prepared for example as in Example 1 in the copending application Ser. No. 378,836 previously noted.

Metal dipole suspension may, for example, be prepared as described herein. In this connection, reference is made to a technical paper entitled Behavior of Unidirectionally Solidified Al-Al Ni Eutectic by Lemkey, Hertzberg and Ford, Transactions of the Metallurgical Society of AIME, February 1965, vol. 233, pp. 334441.

In this article, it is shown that at a growth velocity exceeding 3 cm. per hour, a spaced rod-like structure occurs initially. The spacing between the rods, and the rod diameter becomes smaller as the velocity increases. The rod spacing is proportional to the inverse square root of the growth velocity. For example, extrapolation to 300 cm. per hour shows particle separation of 0.2 microns with a rod diameter of about 300 A.

The thermal gradient was between 25 and 37 C. per cm. A greater temperature gradient, which results in smaller dipole rods, may be obtained by placing the eutectic in a small diameter tube, such as a quartz tube, having an inside diameter of 1 mm.

To achieve a dipole diameter of 50-300 A., a thermal gradient of about 300 C. per cm. may be used at a growth velocity of about 0.13 cm./sec. After the rods are grown, the matrix is then dissolved away utilizing an acid, such as dilute hydrochloric acid. The particles may be further decreased in size by washing them with a suitable acid, such as hydrochloric acid, until the optimum diameter and length has been obtained. The dipole rods remaining undissolved are washed with water, and then with alcohol and acetone and dispersed in a solvent containing a polymer as described above.

The invention may be employed in the coating of lenses using a spin coating technique as follows with particular reference being made to FIG. 12.

The object is to apply fields of the order of 200 to 300 kv./cm. across an air gap in which the coating is placed. The purpose of the device is to obtain maximum orientations and extremely large electrodichroic ratios for coatings oriented in the plane of the surface of the lens. The effect is essentially electrostatic and the currents employed would generally be in the microampere range. The electric field is preferably applied across a distance not exceeding about 7 cms. on most lens applications, an electric field of upwards of 1 million volts being contemplated for such a distance, the voltage being AC or DC. Since the gap normally required for a field of 1 million volts is about 33 cms., the electric breakdown strength must be increased by about times. This may be accomplished by placing the element to be coated and aligned in a pressure tank operating at about 5 times atmospheric pressure or approximately 75 p.s.i.

In FIG. 12, a cylindric chamber 40 is provided with a cover 41 sealed by O-rings 42. A shaft 43 passes through cylindrical chamber 40 via a sealed bearing 44, the shaft being inserted into the extending end on insulated body 45. Slip rings 46 and 47 are connected through insulated bushings 48 and 49, respectively, to terminals 50 and 5-1.

The bushings 48 and 49 should be large enough in diameter so that the path length between the exposed conductors and the walls on the interior is greater than that which would afford a spark breakdown path under the established interior pressure conditions. Exterior atmospheric pressure conditions can be tolerated provided bushings 48 and 49 are extended sufficiently outward to provide at least a 33 cm. total gap or they may be alternatively immersed in an insulating oil bath 52. The dipole fluid 53 is poured on lens 54 held within spin holder 54A and rotated along with electrodes 55 and 56 between which the intense electric field is established. Excess fluid is thrown oiT and the dipoles are oriented to very nearly parallelism. Provision should be made for the evaporation of the solvent and for the provision of additional air to carry away the evaporated solvent. This may be done with an air source pipe 57 and an exit pipe 58 connected to a valve which controls the flow of air through the chamber.

The interior 59 of the chamber is desirably maintained at a pressure of at least 75 p.s.i. before the application of the voltage. When the operation is complete, the dipolar particles are aligned and evaporation has occurred to solidify coating 53. The voltage is then turned off and the rotation of shaft 43 stopped. The pressure within the chamber is released and the top 41 removed so that the coated lens can be taken out of the spin holder and another inserted.

A polarizing medium results after fluid layer shown in FIG. 12 has solidified (as by cooling if the fluid is a thermoplastic or a glass). For example, the dipoles may be metal needles, such as platinum, and the medium a low melting point low viscosity glass, such as solder glass.

The dipole particles utilized in polariz'ers according to this invention differ from those of prior art polarizers, such as Polaroid J polarization which was an oriented herapathite suspension in cellulose acetate butyrate. The dipoles of the present invention are controlled in size and shape to close tolerances, whereas those of the prior art were of random size and shape. Consequently, polarizers produced in accordance with this invention have no perceptible light scatter. Light scatter was a particularly serious disadvantage of prior art polarizers which were a result of the process of manufacturing, which caused larger particles to be produced in situ.

As stated hereinbefore, semiconductors, as set forth, may be employed in the preparation of such dipoles as described.

PREPARATION OF SUBMICRON HERAPATHITE CRYSTALS To produce submicron herapathite crystals in high concentration in a low viscosity suspending fluid, which form an optically clear, non-scattering dipole particle suspension of suitable electrodichroic ratio and sensitivity, the reacting solutions should be:

(1) miscible (2) near maximum concentration (3) at low viscosity (4) at low temperature (5) rapidly mixed in reacting proportions (6) violently agitated.

An example follows:

EXAMPLE A No. 1: Parts by wt. Iodine 20 Normal propanol The iodine is dissolved in the normal propanol by heating and shaking.

No. 2: Parts by wt. Quinine bisulphate 32.5 Methanol 67.5

For complete solution warm with agitation in a hot water bath to about 70 C.

Solutions Nos. 2 and 3 are then heated to 70 C. and used to prepare No. 4.

Percent Material Percent Solution solids Butyl acetate Total This solution is then warmed to 70 C. and pressure filtered at the same temperature to remove any small undissolved crystal which would act as nuclei for crystallization.

Solutions Nos. 1 and 4 are then mixed in proportion and rapidly mixed in a container cooled by an acetone Dry-Ice bath. The result is:

A herapathite suspension prepared in this manner is characterized by elongated submicrpn crystals of herapathite, which remain in suspension without settling and which is suitable for use as a dipole particle suspension in the practice of this invention.

(Bhemically, herapathite is quininetrisulphate dihydro iodide tetraiodide hexahydrate, the chemical name for Before reaction Alter reaction Parts Percent Solids Solids s l l d Io n 20.0 1.8 {E191ll;o?l%fff?::::::: :;22-. 3.-1 ..f.' 32::

Total 100 5.5 12.37 100.0 IQs While Solution No. is being prepared, alkyl epoxy stearate (Cellufiex-23), a high boiling solvent also known as a plasticizer is cooled in an ice bath to 0 C., and added in the following-proportions to make a paste containing the submicron herapathite particles in suspension: 25

No. 6 is then mixed with a mechanical stirrer for about 10 minutes to insure complete reaction and homogenity. After this, to remove the volatile solvents, the suspension No. 6 is placed in a rotating evacuator for about 2 hours and a paste is then obtained which is substantially free from solvents except the plasticizer and which has a resistivity of at least 30 megohm-cm.

The analysis of the paste resulting from No. 6 after the volatiles have been removed is:

No. 7: Parts by wt. Iodoquinine sulphate 13.0 Nitrocellulose 16.3 Cellufiex-23 70.7

As a diluent for the paste, there is then prepared:

No. 8: Parts by wt.

Xylol 80 55 Butyl acetate 20 No. 9: Parts by wt.

No. 7 0 No. 8 50 100 A solids analysis of No. 9 is as follows:

Percent 65 Solids solids Iodoquinine sulphate 6. 5 44. 3

Nitrnr-Pllnlnsn 8. 15 7 Total 14.65 100. o 70 Norm-See the following table:

Percent solids total 14. Percent IQS in suspensiom- 6. 5

No. 9 may be used directly or be centrifuged to obtain a supernatent liquid for use in an electrodichroic system.

The molecular weight is 2,464.

Stpichiometrically herapathite contains approximately 25.8% of iodine which is approximately a ratio of iodine to quinine bisulphate of /3. 1

However, I have found that the proportions can be varied from V: through M4. This is; apparently due to herapathite being a molecular compound or a mixed crystal in which the proportion of the components may vary.

Moreover, the HI in the compound is present in the proportion of two moles of quinine to one of HI. The heating of the iodine solution No. 1" usually sufiices to provide sufiieient HI as set forth in the above example. The presence of HI in stoichiometr ic quantities is re quired to form a stable crystalline compound. An additional quantity of HI may be added to achieve the molar ratio set forth.

Generally, I have found the composition of Example A to be satisfactory, and this composition has been used in most of the tests.

As will be appreciated from the foregoing disclosure,

' the embodiments provided bythe invention are many and varied. For example, as one embodiment, an article of manufacture is provided comprising a matrix having dis persed substantially uniformly at least at the surface thereof a plurality of dipoles selected from the group consisting of electrically conductive and semi-conductive material, such as metal or herapathitedipoles, the matrix being a medium capable of being in the fluid state during the initial dispersion of the dipoles whereby said dipoles are capable of rotation to a desired preferred orientation upon the application of a force field. Thus, the liquid state of the matrix may be in the form of a solution that dries during the application of the .;force field, or the medium forming the matrix may be one which is con verted to the fluid state by the application of heat, but which is capable of hardening during the application of a force field. The matrix might be a coating applied to a surfage, such as a curable plastic coating; or it might be a coating applied to a transparent substrate, such as glass or a'hard plastic.

The dipoles dispersed in the matrix may have an aver-= age length of about ll/2ni50% and an average diameter ranging up to about )\/l0ni50%, A being the wavelengthof light and n the index of refraction of the matrix medium. Depending on the wavelength of the particular light striking the surface, the dipoles may range in length from about 1000 A. to 10,000 A.

The number of particles in a unit area of matrix me dium may be determined simply by using the formula N=8n /x The interparticle spacing of the dipoles oriented in the plane of the matrix medium is generally at least about the effective cross section of the dipole divided by its average length, the effective cross section being determined by the formula:

Effective cross section=) /8n Another embodiment provided by the invention is a composition of matter for a light controlling device comprising a transparent suspending medium and a plurality of dipole particles selected from the group consisting of conductive and semi conductive material suspended in the medium, the medium being one which is capable of being in a fluid state to enable the dipoles to be rotated to a preferred orientation upon the application of a non-constant force field, the medium being then capable of being solidified at ambient temperatures during the application of the force field in order to fix the particular orientation of the dipoles desired. The type of dipole particles employed may be the same as those discussed hereinbefore.

A further embodiment is an article of manufacture in the form of a solid transparent layer of a medium having substantially uniformly dispersed therethrough said dipole particles having a preferred orientation relative to the plane of the transparent layer. The transparent layer may be a material selected from the group consisting of glass and plastic. glass, is meant any transparent inorganic material capable of being worked into any desired shape, either bymelting and shaping the glass, or by forming a coating of the glass-like material onto a transparent substrate, such as with a solution which, upon drying, leaves a glass-like coating. Similarly, by plastic, is meant any transparent organic material which is capable of being softened and shaped into any desired form or which can be employed as a solution which leaves a coating after the solution has been evaporated from a layer deposited by the solution. In any event, it is any material of the foregoing type which is capable of having a fluid state during which dipole particles dispersed through the fluid can be oriented by using a nonconstant force field, which force field is maintained until it is caused to harden or cure or form a permanent layer by drying.

As another embodiment, the invention provides a polarizer comprising a solid layer of transparent medium, such as glass or plastic, having a substantially uniform dispersion therethrough of dipole particles oriented in the plane of the layer, selected from the group consisting of electrically conductive and semi-conductive particles, the particles preferably and advantageously having an average length of about x/2n:50% and a diameter ranging up to about A/lOni-50%. As stated above, the dipole particles may advantageously be metallic and be spaced from each other in accordance with the preferred limitations stated hereinbefore.

The invention also provides a composite article of manufacture comprising a substrate of a transparent material having a transparent optical coating thereon, such as glass or plastic, and containing a dispersion of dipole particles similarly as described herein.

The method embodiment of the invention for producing an article of manufacture of a transparent medium having preferred optical properties resides in providing the medium, e.g. glass or plastic, in the fluid state containing a uniform dispersion of dipole particles selected from the group consisting of electrically conductive and semi-conductive material (e.g. metal dipoles), in forming a layer of the material in the fluid state, in subjecting the layer to the action of a force field whereby to orient said dipoles in a predetermined direction, and in maintaining the force field while allowing the layer to solidify. The solidification referred to may be the result of drying the fluid, allowing the fluid to harden or cure which, in the case of glass, would harden by cooling and the same is true for some plastics. However, the plastic might have a curing catalyst which causes hardening to take place while the force field is maintained.

The methods disclosed hereinabove may similarly be employed in producing a coated substrate or transparent material in which the coating may be of glass or plastic containing dipoles which is applied to the substrate in a fluid state and the dipoles similarly oriented in the plane of the coating using the non-constant force field.

A method which may be employed in effecting the orientation of dipole particles in a transparent medium resides in providing the medium as a layer in the plastically deformable state (e.g. glass or plastic) containing a uniform dispersion of dipole particles, in physically stretching the layer unidirectionally so as to orient the dipoles in the plane of the layer in the direction of, stretch, and then allowing the stretched layer to congeal or harden to permanently fix the oriented positions of the dipoles dispersed in the layer. 1 t

It will be understood that in polarizersr'nade irraccordance with this invention, the flakes (e.g. aluminum flakes) are oriented normal to the surface and in pafallel planes as shown in FIG. 8A. The orientation-shown in FIG. 8A may be obtained by momentarily. applying a pulsed electriefield along the Z axis, followed immediately by a pulsed electric field along the X axis, whereby the particles are oriented along the respective axes. The pulses are applied sufliciently rapidly, for example at a repetition rate of about 10001. per second so that the flakes do not have a chance to disorient between successive pulses. Thus, the plane of substantially eachlof the flakes, when oriented, may be parallel to two'of the axes. For example, the plane of substantially each of the oriented particles may be parallel to the plane ofthe layer, or normal thereto.

Although the present invention has been described in conjunction with preferred embodiments, it is to be understood that modifications and variations may be resorted to without departing from the spirit and scope of the invention as those skilled in the art will readily understand. Such modifications and variations are considered to be within the purview and scope of the invention and the appended claims.

What is claimed is: I

1. A method of producing an article of manufacture of a transparent medium having preferred optical properties which comprises, providing said medium in the fluid state containing a uniform dispersion of dipole particles selected from the group consisting of electrically conductive and semi-conductive material, and dichroic crystals, forming a layer of said material in the fluid state, subjecting said layer to the action of a force fiel'd whereby to orient said dipoles in a predetermined direction, and maintaining said force field while allowing said, layer to solidify.

2. The method of claim 1, wherein the dipoles are metallic and have an average length of about A/2ni50% and an average diameter ranging up to about where A is the wavelength of light and n the index of refraction of the transparent material.

3. The method of claim 2, wherein the transparent medium is selected from the group consisting of glass and plastic.

4. The method of claim 3, wherein the transparent medium is rendered fluid by the application of heat.

5. The method of claim 3, wherein the transparent medium is a plastic dissolved in a solvent and wherein the dissolved plastic is converted to a solid layer by allowing the solvent to evaporate during the application of the force field.

6. The method of claim 2, wherein the dipole particles employed have an average length ranging from about 1000 A. to 10,000 A.

7. The method of claim 6, wherein the force field is applied to orient the dipole particles in the plane of the layer, and wherein the number of partirles per unis area 21 is at least the reciprocal of the effective cross section per particle.

8. A method of producing a coated substrate of transparent medium having preferred optical properties which comprises, coating said substrate with a transparent coating medium in the fluid state containing a uniform dispersion of dipole particles selected from the group consisting of electrically conductive and selmi-q'onductive material, and dichroic crystals, forming a coating of said transparent coating medium in the fluid state, subjecting said coating to the action of a force field whereby to orient said dipoles in a predetermined direction, and maintaining said force field while allowing said coating to solidify.

9. The method of claim 8, wherein the dipoles are metallic and have an average length of about A/2n:50% and an average diameter ranging up to about A/lni50%,

where x is the wavelength of light and n the index of refraction of the transparent material.

10. The method of claim 9, wherein the transparent coating medium is selected from the group consisting of glass and plastic.

' 11. The method of claim 10, wherein the transparent coating medium is rendered fluid by the application of heat.

12. The method of claim 10, wherein the transparent coating medium is a plastic dissolved in a solvent and wherein the plastic is converted to a solid layer by allowing the solvent to evaporate during the application of the force field.

13. The method of claim 9, wherein the dipole particles employed have an average length ranging from about 1000 A. to 10,000 A.

14. The method of claim 13, wherein the force field is applied to orient the dipole particles in the plane of the coating, and wherein the number of particles per unit area is at least the reciprocal of the effective cross section per particle.

15. A method of producing an article of manufacture of a transparent medium having preferred optical properties which comprises, selecting submicron particles having a predetermined size range, providing said medium as a layer in the plastically deformable state containing a uni-form dispersion of said submicron dipole particles selected from the group consisting of electrically conductive and semi-conductive material, and dichroic crystals, physically stretching said layer unidirectionally whereby to orient said dipoles in the plane of said layer in the direction of stretch, and then allowing said stretched layer to congeal or harden to permanently fix the oriented positions of said dipoles.

16. The method of claim 15, wherein the dipoles are metallic and have an average length of about A/2n:50% and an average diameter ranging up to about where A is the wavelength of light and n the index of refraction of the transparent material.

17. The method of claim 16, wherein the transparent medium is selected from the group consisting of glass and lastic. p 18. The method of claim 17, wherein the transparent medium is rendered plastically deformable by the application of heat.

19. The method of claim 16, wherein the dipole particles employed have an average length ranging from about 1000 A. to 10,000 A.

20. The method of claim 19, wherein the number of particles per unit area is at least the reciprocal of the efiective cross section per particle.

21. A method for producing a transparent plastic sheet having polarizing properties which comprises, continously coating the surface of a transparent plastic sheet with a fluid layer of polymer solution containing a dispersion of dipole particles selected from the group consisting of electrically conductive and semi-conductive material, and dichroic crystals, moving the sheet with the fluid layer through an electrical force field, the lines of force of said field being disposed longitudinally of said" sheet whereby said dipole particles are oriented parallel to the sheet in the longitudinal direction of said sheet, and then solidifying said fiuid layer while the dipoles are still in their oriented position.

22. The method of claim 21, wherein the dipoles are metallic and have an average length of about h/21ii50% and an average diameter ranging up to about where x is the wavelength of light and n is the index of refraction of the transparent material.

23. The method of claim 22, wherein the dipole particles employed'have an average length ranging from about 1000 A. tc 10,000 A.

24. The method of claim 23, wherein the number of particles per unit area is at least the reciprocal of the etfective cross section per particle.

25. A methodjfor providing a lens with a plasticcoating containing dipole particles oriented in a preferred direction, said dipole particles conferring polarizing prop erties to said lens, which comprises, supporting said lens on a rotatably inounted lens support, coating said. lens with a polymer solution containing said dipole particles, applying a force field diametrically across said lens, said force field beingfixed relative to said lens supportj such that as the lens support is rotated, said fixed forcgfield is rotated with said lens support, maintaining said coated lens within a housing to which is fed gas under pressure, rotating said lensf support to uniformly spread the coating over the lense while applying said force field, and allowing said coating to solidify on said lens during the application of said forcefield.

26. A methodifor providing a lens with a plastic coating containing dipole particles oriented in a preferred direction, said dipole particles conferring polarizing prop erties to said lens, which comprises, supporting said lens on a rotatably mounted lens support, coating said lens with a polymer solution containing said dipole particles, applying a force field diametrically across said lens, saidl force field being fixed relative to said lens support such that as the lens support is rotated, said fixed force field is rotated with said lens support, rotating said lens support to uniformly spread the coating over the lens While apply-= ing said force field, and allowing said coating to solidify on said lens during the application of said force field.

27. The method of claim 26, wherein the dipoles are metallic and have an average length of about h2n/ and an average diameter ranging up to about A/l0ni50%, where A is the wavelength of light and n is the index of refraction of the transparent material.

28. The method of claim 26, wherein the dipole particles employed have an average length ranging from about 1000 A. to 10,000 A.

29. The method of claim 27, wherein the number of particles per unit area is at least the reciprocal of the effective cross section per particle.

30. A method of producing a polarizer comprising a transparent medium which comprises, providing a hardenable medium in the fluid state containing a uniform dis-= persion of flake particles selected from the group consisting of electrically conductive and semi-conductive material, and dichroic crystals, forming a layer of said ma terial in the fluid state with the plane of the layer referenced to the X, Y and Z axes, subjecting said layer to a momentary pulsed electric field along one axis followed immediately by a pulsed electric field along one of the other axes, whereby the particles are oriented along the said two respective axes, the pulses being applied with References Cited UNITED STATES PATENTS Bird 350-147 Weiss 350-147 X Marks 350-152 X Marks 350-147 X Rosenthal 350-150 U X 24 Land 350-157 Makas 264--2 Cranson 264-2 Pollack 264-2 Land 264-2 Land 264-2 LEON D. DO,SDOL, Primary Examiner M. F. ESPOSITO, Assistant Examiner US. Cl. X.R.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3'8l5'265 Dated y 97 Inventor s Alvinv M. Marks It -is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Columh 1', line 60 A 10h" s *ould "be Column 7, line 59 "center di tance between the longitudin 1 axis" should be --the ligh ray and parallel to the ele tric vector", v i

line 65 "adsorpti'o' should he .s --.absorpti n-. i Q I I Column 8, line 66 "in" should be is.

Column 22 line 54 Q (Claim 27) 2nl" should be I A/ n c Q Q Column 23, line 3 (Claim 30) "which" should be while- 0 Signed and Sealed this Twenty-third D3) 0f November 1976 [SEAL]' Arrest:

g RUTH MASON c. MARSHALL DANN mum"! fi Commissioner nfParems and Trademarks

Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US4125319 *May 3, 1976Nov 14, 1978Eastman Kodak CompanyActive light control device
US4630097 *Aug 16, 1983Dec 16, 1986Marks Alvin M2D/3D compatible polarized color TV system
US5006285 *Jul 28, 1988Apr 9, 1991Lockheed Missiles & Space Company, Inc.Electro-optic channel waveguide
US5308552 *Jul 10, 1992May 3, 1994Hughes Aircraft CompanyMethod of fabricating anisometric metal needles and birefringent suspension thereof in dielectric fluid
US5364689 *Oct 21, 1992Nov 15, 1994Hashimoto Forming Industry Co., Ltd.Painting with magnetically formed pattern and painted product with magnetically formed pattern
US5376463 *Sep 20, 1993Dec 27, 1994Hughes Aircraft CompanyAnisometric metal needles with L-shaped cross-section
US5630877 *May 25, 1995May 20, 1997Hashimoto Forming Industry Co., Ltd.Electromagnetism, high speed, simplification
US5835255 *May 5, 1994Nov 10, 1998Etalon, Inc.Visible spectrum modulator arrays
US5986796 *Nov 5, 1996Nov 16, 1999Etalon Inc.Visible spectrum modulator arrays
US6040937 *Jul 31, 1996Mar 21, 2000Etalon, Inc.Interferometric modulation
US6055090 *Jan 27, 1999Apr 25, 2000Etalon, Inc.Interferometric modulation
US6650455Nov 13, 2001Nov 18, 2003Iridigm Display CorporationPhotonic mems and structures
US6674562Apr 8, 1998Jan 6, 2004Iridigm Display CorporationInterferometric modulation of radiation
US6680792Oct 10, 2001Jan 20, 2004Iridigm Display CorporationInterferometric modulation of radiation
US6710908Feb 13, 2002Mar 23, 2004Iridigm Display CorporationControlling micro-electro-mechanical cavities
US6867896Sep 28, 2001Mar 15, 2005Idc, LlcInterferometric modulation of radiation
US7012726Nov 3, 2003Mar 14, 2006Idc, LlcMEMS devices with unreleased thin film components
US7012732Mar 1, 2005Mar 14, 2006Idc, LlcMethod and device for modulating light with a time-varying signal
US7042643Feb 19, 2002May 9, 2006Idc, LlcInterferometric modulation of radiation
US7060895May 4, 2004Jun 13, 2006Idc, LlcModifying the electro-mechanical behavior of devices
US7110158Aug 19, 2002Sep 19, 2006Idc, LlcPhotonic MEMS and structures
US7119945Mar 3, 2004Oct 10, 2006Idc, LlcAltering temporal response of microelectromechanical elements
US7123216Oct 5, 1999Oct 17, 2006Idc, LlcPhotonic MEMS and structures
US7126738Feb 25, 2002Oct 24, 2006Idc, LlcVisible spectrum modulator arrays
US7130104Jun 16, 2005Oct 31, 2006Idc, LlcMethods and devices for inhibiting tilting of a mirror in an interferometric modulator
US7138984Jun 5, 2001Nov 21, 2006Idc, LlcDirectly laminated touch sensitive screen
US7161094May 18, 2006Jan 9, 2007Idc, LlcModifying the electro-mechanical behavior of devices
US7161728Dec 9, 2003Jan 9, 2007Idc, LlcArea array modulation and lead reduction in interferometric modulators
US7161730Jul 22, 2005Jan 9, 2007Idc, LlcSystem and method for providing thermal compensation for an interferometric modulator display
US7164520May 12, 2004Jan 16, 2007Idc, LlcPackaging for an interferometric modulator
US7187489Jun 1, 2006Mar 6, 2007Idc, LlcPhotonic MEMS and structures
US7193768Mar 24, 2004Mar 20, 2007Qualcomm Mems Technologies, Inc.Interference display cell
US7198973Nov 13, 2003Apr 3, 2007Qualcomm Mems Technologies, Inc.Method for fabricating an interference display unit
US7221495Jun 24, 2003May 22, 2007Idc LlcThin film precursor stack for MEMS manufacturing
US7236284Oct 21, 2005Jun 26, 2007Idc, LlcPhotonic MEMS and structures
US7250315Sep 14, 2004Jul 31, 2007Idc, LlcMethod for fabricating a structure for a microelectromechanical system (MEMS) device
US7256922Jul 2, 2004Aug 14, 2007Idc, LlcInterferometric modulators with thin film transistors
US7259449Mar 16, 2005Aug 21, 2007Idc, LlcMethod and system for sealing a substrate
US7259865Nov 17, 2005Aug 21, 2007Idc, LlcProcess control monitors for interferometric modulators
US7280265May 12, 2004Oct 9, 2007Idc, LlcInterferometric modulation of radiation
US7289256Apr 1, 2005Oct 30, 2007Idc, LlcElectrical characterization of interferometric modulators
US7289259Feb 11, 2005Oct 30, 2007Idc, LlcConductive bus structure for interferometric modulator array
US7291921Mar 29, 2004Nov 6, 2007Qualcomm Mems Technologies, Inc.Structure of a micro electro mechanical system and the manufacturing method thereof
US7297471Apr 15, 2003Nov 20, 2007Idc, LlcMethod for manufacturing an array of interferometric modulators
US7299681Mar 25, 2005Nov 27, 2007Idc, LlcMethod and system for detecting leak in electronic devices
US7302157Apr 1, 2005Nov 27, 2007Idc, LlcSystem and method for multi-level brightness in interferometric modulation
US7304784Jul 21, 2005Dec 4, 2007Idc, LlcReflective display device having viewable display on both sides
US7317568Jul 29, 2005Jan 8, 2008Idc, LlcSystem and method of implementation of interferometric modulators for display mirrors
US7321456Apr 11, 2005Jan 22, 2008Idc, LlcMethod and device for corner interferometric modulation
US7321457Jun 1, 2006Jan 22, 2008Qualcomm IncorporatedProcess and structure for fabrication of MEMS device having isolated edge posts
US7327510Aug 19, 2005Feb 5, 2008Idc, LlcProcess for modifying offset voltage characteristics of an interferometric modulator
US7342709Mar 26, 2003Mar 11, 2008Qualcomm Mems Technologies, Inc.Optical interference type of color display having optical diffusion layer between substrate and electrode
US7343080Jul 1, 2005Mar 11, 2008Idc, LlcSystem and method of testing humidity in a sealed MEMS device
US7349136May 27, 2005Mar 25, 2008Idc, LlcMethod and device for a display having transparent components integrated therein
US7349139May 3, 2006Mar 25, 2008Idc, LlcSystem and method of illuminating interferometric modulators using backlighting
US7355780Feb 11, 2005Apr 8, 2008Idc, LlcSystem and method of illuminating interferometric modulators using backlighting
US7359066Mar 4, 2005Apr 15, 2008Idc, LlcElectro-optical measurement of hysteresis in interferometric modulators
US7368803Mar 25, 2005May 6, 2008Idc, LlcSystem and method for protecting microelectromechanical systems array using back-plate with non-flat portion
US7369252Nov 17, 2005May 6, 2008Idc, LlcProcess control monitors for interferometric modulators
US7369292May 3, 2006May 6, 2008Qualcomm Mems Technologies, Inc.Electrode and interconnect materials for MEMS devices
US7369294Aug 20, 2005May 6, 2008Idc, LlcOrnamental display device
US7369296Aug 5, 2005May 6, 2008Idc, LlcDevice and method for modifying actuation voltage thresholds of a deformable membrane in an interferometric modulator
US7372613Apr 22, 2005May 13, 2008Idc, LlcMethod and device for multistate interferometric light modulation
US7372619May 23, 2006May 13, 2008Idc, LlcDisplay device having a movable structure for modulating light and method thereof
US7373026Jul 1, 2005May 13, 2008Idc, LlcMEMS device fabricated on a pre-patterned substrate
US7379227Feb 11, 2005May 27, 2008Idc, LlcMethod and device for modulating light
US7382515Jan 18, 2006Jun 3, 2008Qualcomm Mems Technologies, Inc.Silicon-rich silicon nitrides as etch stops in MEMS manufacture
US7385744Jun 28, 2006Jun 10, 2008Qualcomm Mems Technologies, Inc.Support structure for free-standing MEMS device and methods for forming the same
US7388704Jun 30, 2006Jun 17, 2008Qualcomm Mems Technologies, Inc.Determination of interferometric modulator mirror curvature and airgap variation using digital photographs
US7403323Nov 17, 2005Jul 22, 2008Idc, LlcProcess control monitors for interferometric modulators
US7405861May 2, 2005Jul 29, 2008Idc, LlcMethod and device for protecting interferometric modulators from electrostatic discharge
US7405863Jun 1, 2006Jul 29, 2008Qualcomm Mems Technologies, Inc.Patterning of mechanical layer in MEMS to reduce stresses at supports
US7405924Mar 25, 2005Jul 29, 2008Idc, LlcSystem and method for protecting microelectromechanical systems array using structurally reinforced back-plate
US7415186Sep 1, 2005Aug 19, 2008Idc, LlcMethods for visually inspecting interferometric modulators for defects
US7417735Aug 5, 2005Aug 26, 2008Idc, LlcSystems and methods for measuring color and contrast in specular reflective devices
US7417783Jul 1, 2005Aug 26, 2008Idc, LlcMirror and mirror layer for optical modulator and method
US7417784Apr 19, 2006Aug 26, 2008Qualcomm Mems Technologies, Inc.Microelectromechanical device and method utilizing a porous surface
US7420725Apr 29, 2005Sep 2, 2008Idc, LlcDevice having a conductive light absorbing mask and method for fabricating same
US7420728Mar 25, 2005Sep 2, 2008Idc, LlcMethods of fabricating interferometric modulators by selectively removing a material
US7424198Jan 28, 2005Sep 9, 2008Idc, LlcMethod and device for packaging a substrate
US7429334Mar 25, 2005Sep 30, 2008Idc, LlcMethods of fabricating interferometric modulators by selectively removing a material
US7450295Mar 2, 2006Nov 11, 2008Qualcomm Mems Technologies, Inc.Methods for producing MEMS with protective coatings using multi-component sacrificial layers
US7453579Sep 9, 2005Nov 18, 2008Idc, LlcMeasurement of the dynamic characteristics of interferometric modulators
US7460246Feb 24, 2005Dec 2, 2008Idc, LlcMethod and system for sensing light using interferometric elements
US7460291Aug 19, 2003Dec 2, 2008Idc, LlcSeparable modulator
US7463398 *Jan 24, 2003Dec 9, 2008Liquivista B.V.Display device
US7471442Jun 15, 2006Dec 30, 2008Qualcomm Mems Technologies, Inc.Method and apparatus for low range bit depth enhancements for MEMS display architectures
US7476327May 4, 2004Jan 13, 2009Idc, LlcMethod of manufacture for microelectromechanical devices
US7483197Mar 28, 2006Jan 27, 2009Idc, LlcPhotonic MEMS and structures
US7492502Aug 5, 2005Feb 17, 2009Idc, LlcMethod of fabricating a free-standing microstructure
US7505117Jun 29, 2005Mar 17, 2009Kabushiki Kaisha ToshibaPolarizing element, method of manufacturing polarizing element, method of evaluating exposure apparatus, method of manufacturing semiconductor device, and exposure apparatus
US7527995May 20, 2005May 5, 2009Qualcomm Mems Technologies, Inc.Method of making prestructure for MEMS systems
US7527996Apr 19, 2006May 5, 2009Qualcomm Mems Technologies, Inc.Non-planar surface structures and process for microelectromechanical systems
US7527998Jun 30, 2006May 5, 2009Qualcomm Mems Technologies, Inc.Method of manufacturing MEMS devices providing air gap control
US7532194Feb 3, 2004May 12, 2009Idc, LlcDriver voltage adjuster
US7532377Apr 6, 2006May 12, 2009Idc, LlcMovable micro-electromechanical device
US7534640Jul 21, 2006May 19, 2009Qualcomm Mems Technologies, Inc.Support structure for MEMS device and methods therefor
US7535466Apr 1, 2005May 19, 2009Idc, LlcSystem with server based control of client device display features
US7547565May 20, 2005Jun 16, 2009Qualcomm Mems Technologies, Inc.Method of manufacturing optical interference color display
US7547568Feb 22, 2006Jun 16, 2009Qualcomm Mems Technologies, Inc.Electrical conditioning of MEMS device and insulating layer thereof
US7550794Sep 20, 2002Jun 23, 2009Idc, LlcMicromechanical systems device comprising a displaceable electrode and a charge-trapping layer
US7550810Feb 23, 2006Jun 23, 2009Qualcomm Mems Technologies, Inc.MEMS device having a layer movable at asymmetric rates
US7553684Jun 17, 2005Jun 30, 2009Idc, LlcMethod of fabricating interferometric devices using lift-off processing techniques
US7554711Jul 24, 2006Jun 30, 2009Idc, Llc.MEMS devices with stiction bumps
US7554714Jun 10, 2005Jun 30, 2009Idc, LlcDevice and method for manipulation of thermal response in a modulator
US7564612Aug 19, 2005Jul 21, 2009Idc, LlcPhotonic MEMS and structures
US7564613Oct 9, 2007Jul 21, 2009Qualcomm Mems Technologies, Inc.Microelectromechanical device and method utilizing a porous surface
US7566664Aug 2, 2006Jul 28, 2009Qualcomm Mems Technologies, Inc.Selective etching of MEMS using gaseous halides and reactive co-etchants
US7567373Jul 26, 2005Jul 28, 2009Idc, LlcSystem and method for micro-electromechanical operation of an interferometric modulator
US7570865Jan 28, 2008Aug 4, 2009Idc, LlcSystem and method of testing humidity in a sealed MEMS device
US7582952Feb 21, 2006Sep 1, 2009Qualcomm Mems Technologies, Inc.Method for providing and removing discharging interconnect for chip-on-glass output leads and structures thereof
US7586484Apr 1, 2005Sep 8, 2009Idc, LlcController and driver features for bi-stable display
US7603001Feb 17, 2006Oct 13, 2009Qualcomm Mems Technologies, Inc.Method and apparatus for providing back-lighting in an interferometric modulator display device
US7616369Mar 31, 2006Nov 10, 2009Idc, LlcFilm stack for manufacturing micro-electromechanical systems (MEMS) devices
US7618831Nov 17, 2005Nov 17, 2009Idc, LlcMethod of monitoring the manufacture of interferometric modulators
US7622167 *Oct 20, 2003Nov 24, 2009Nitto Denko CorporationPolarizer, method for manufacturing the same, optical film and image display
US7623287Apr 19, 2006Nov 24, 2009Qualcomm Mems Technologies, Inc.Non-planar surface structures and process for microelectromechanical systems
US7623752Jan 28, 2008Nov 24, 2009Idc, LlcSystem and method of testing humidity in a sealed MEMS device
US7630114Oct 28, 2005Dec 8, 2009Idc, LlcDiffusion barrier layer for MEMS devices
US7630119Aug 12, 2005Dec 8, 2009Qualcomm Mems Technologies, Inc.Apparatus and method for reducing slippage between structures in an interferometric modulator
US7630123Jan 21, 2005Dec 8, 2009Qualcomm Mems Technologies, Inc.Method and device for compensating for color shift as a function of angle of view
US7636151Jun 15, 2006Dec 22, 2009Qualcomm Mems Technologies, Inc.System and method for providing residual stress test structures
US7642110Jul 30, 2007Jan 5, 2010Qualcomm Mems Technologies, Inc.Method for fabricating a structure for a microelectromechanical systems (MEMS) device
US7643203Apr 10, 2006Jan 5, 2010Qualcomm Mems Technologies, Inc.Interferometric optical display system with broadband characteristics
US7649671Jun 1, 2006Jan 19, 2010Qualcomm Mems Technologies, Inc.Analog interferometric modulator device with electrostatic actuation and release
US7653371Aug 30, 2005Jan 26, 2010Qualcomm Mems Technologies, Inc.Selectable capacitance circuit
US7668415Mar 25, 2005Feb 23, 2010Qualcomm Mems Technologies, Inc.Method and device for providing electronic circuitry on a backplate
US7684104Aug 22, 2005Mar 23, 2010Idc, LlcMEMS using filler material and method
US7692839Apr 29, 2005Apr 6, 2010Qualcomm Mems Technologies, Inc.System and method of providing MEMS device with anti-stiction coating
US7692844Jan 5, 2004Apr 6, 2010Qualcomm Mems Technologies, Inc.Interferometric modulation of radiation
US7701631Mar 7, 2005Apr 20, 2010Qualcomm Mems Technologies, Inc.Device having patterned spacers for backplates and method of making the same
US7706044Apr 28, 2006Apr 27, 2010Qualcomm Mems Technologies, Inc.Optical interference display cell and method of making the same
US7706050Mar 5, 2004Apr 27, 2010Qualcomm Mems Technologies, Inc.Integrated modulator illumination
US7710629Jun 3, 2005May 4, 2010Qualcomm Mems Technologies, Inc.System and method for display device with reinforcing substance
US7710636Aug 22, 2005May 4, 2010Qualcomm Mems Technologies, Inc.Systems and methods using interferometric optical modulators and diffusers
US7711239Apr 19, 2006May 4, 2010Qualcomm Mems Technologies, Inc.Microelectromechanical device and method utilizing nanoparticles
US7719500May 20, 2005May 18, 2010Qualcomm Mems Technologies, Inc.Reflective display pixels arranged in non-rectangular arrays
US7763546Aug 2, 2006Jul 27, 2010Qualcomm Mems Technologies, Inc.Methods for reducing surface charges during the manufacture of microelectromechanical systems devices
US7777954Jan 30, 2007Aug 17, 2010Qualcomm Mems Technologies, Inc.Systems and methods of providing a light guiding layer
US7781850Mar 25, 2005Aug 24, 2010Qualcomm Mems Technologies, Inc.Controlling electromechanical behavior of structures within a microelectromechanical systems device
US7795061Dec 29, 2005Sep 14, 2010Qualcomm Mems Technologies, Inc.Method of creating MEMS device cavities by a non-etching process
US7808703May 27, 2005Oct 5, 2010Qualcomm Mems Technologies, Inc.System and method for implementation of interferometric modulator displays
US7813026Jan 21, 2005Oct 12, 2010Qualcomm Mems Technologies, Inc.System and method of reducing color shift in a display
US7830586Jul 24, 2006Nov 9, 2010Qualcomm Mems Technologies, Inc.Transparent thin films
US7835061Jun 28, 2006Nov 16, 2010Qualcomm Mems Technologies, Inc.Support structures for free-standing electromechanical devices
US7864395Oct 27, 2006Jan 4, 2011Qualcomm Mems Technologies, Inc.Light guide including optical scattering elements and a method of manufacture
US7880954May 3, 2006Feb 1, 2011Qualcomm Mems Technologies, Inc.Integrated modulator illumination
US7893919Jan 21, 2005Feb 22, 2011Qualcomm Mems Technologies, Inc.Display region architectures
US7898718Nov 10, 2008Mar 1, 2011Liquavista B.V.Display device
US7903047Apr 17, 2006Mar 8, 2011Qualcomm Mems Technologies, Inc.Mode indicator for interferometric modulator displays
US7916103Apr 8, 2005Mar 29, 2011Qualcomm Mems Technologies, Inc.System and method for display device with end-of-life phenomena
US7916980Jan 13, 2006Mar 29, 2011Qualcomm Mems Technologies, Inc.Interconnect structure for MEMS device
US7920135Apr 1, 2005Apr 5, 2011Qualcomm Mems Technologies, Inc.Method and system for driving a bi-stable display
US7936497Jul 28, 2005May 3, 2011Qualcomm Mems Technologies, Inc.MEMS device having deformable membrane characterized by mechanical persistence
US8008736Jun 3, 2005Aug 30, 2011Qualcomm Mems Technologies, Inc.Analog interferometric modulator device
US8014059Nov 4, 2005Sep 6, 2011Qualcomm Mems Technologies, Inc.System and method for charge control in a MEMS device
US8040588Feb 25, 2008Oct 18, 2011Qualcomm Mems Technologies, Inc.System and method of illuminating interferometric modulators using backlighting
US8045252Feb 20, 2008Oct 25, 2011Qualcomm Mems Technologies, Inc.Spatial light modulator with integrated optical compensation structure
US8059326Apr 30, 2007Nov 15, 2011Qualcomm Mems Technologies Inc.Display devices comprising of interferometric modulator and sensor
US8068710Dec 7, 2007Nov 29, 2011Qualcomm Mems Technologies, Inc.Decoupled holographic film and diffuser
US8111445Jan 15, 2008Feb 7, 2012Qualcomm Mems Technologies, Inc.Spatial light modulator with integrated optical compensation structure
US8111446Dec 19, 2008Feb 7, 2012Qualcomm Mems Technologies, Inc.Optical films for controlling angular characteristics of displays
US8124434Jun 10, 2005Feb 28, 2012Qualcomm Mems Technologies, Inc.Method and system for packaging a display
US8213071Jan 26, 2011Jul 3, 2012Samsung Lcd Netherlands R & D Center B.V.Display device
US8300304Feb 11, 2009Oct 30, 2012Qualcomm Mems Technologies, Inc.Integrated front light diffuser for reflective displays
US8368981Apr 6, 2009Feb 5, 2013Qualcomm Mems Technologies, Inc.Display device with diffractive optics
US8394656Jul 7, 2010Mar 12, 2013Qualcomm Mems Technologies, Inc.Method of creating MEMS device cavities by a non-etching process
US8416487Jan 26, 2009Apr 9, 2013Qualcomm Mems Technologies, Inc.Photonic MEMS and structures
US8638491Aug 9, 2012Jan 28, 2014Qualcomm Mems Technologies, Inc.Device having a conductive light absorbing mask and method for fabricating same
US8670171Oct 18, 2010Mar 11, 2014Qualcomm Mems Technologies, Inc.Display having an embedded microlens array
US8682130Sep 13, 2011Mar 25, 2014Qualcomm Mems Technologies, Inc.Method and device for packaging a substrate
US8735225Mar 31, 2009May 27, 2014Qualcomm Mems Technologies, Inc.Method and system for packaging MEMS devices with glass seal
US20080223855 *Oct 15, 2006Sep 18, 2008Clearwave Ltd.Microwave Oven Window
US20090008387 *Sep 15, 2008Jan 8, 2009Clearwave Ltd.Microwave Oven Window
USRE40436Jul 7, 2005Jul 15, 2008Idc, LlcHermetic seal and method to create the same
USRE42119Jun 2, 2005Feb 8, 2011Qualcomm Mems Technologies, Inc.Microelectrochemical systems device and method for fabricating same
EP0047162A1 *Aug 28, 1981Mar 10, 1982Kureha Kagaku Kogyo Kabushiki KaishaKerr effect electro-optical element
EP0176781A2 *Sep 2, 1985Apr 9, 1986Alvin M. Dr. MarksOrdered dipolar light-electric power converter
EP0506376A1 *Mar 25, 1992Sep 30, 1992Hughes Aircraft CompanyMethod of fabricating anisometric needles and birefringent suspension thereof in dielectric fluid
EP1555550A1 *Oct 20, 2003Jul 20, 2005Nitto Denko CorporationPolarizer, method for manufacturing the same, optical film and image display
EP1612586A2 *Jun 29, 2005Jan 4, 2006Kabushiki Kaisha ToshibaPolarizing element, method of manufacturing polarizing element, method of evaluating exposure apparatus, method of manufacturing semiconductor device, and exposure apparatus
EP2310895A1 *May 22, 2009Apr 20, 2011Reflexite CorporationLight control films and method thereof
EP2498107A2 *Aug 27, 2008Sep 12, 2012Corning IncorporatedLight-polarizing article and process for making same
WO2008072494A1 *Nov 26, 2007Jun 19, 2008Fujifilm CorpOptical film, and glass
Classifications
U.S. Classification427/473, 427/160, 428/328, 427/123, 427/108, 427/74, 359/296, 427/474, 428/433, 264/1.32, 427/165, 427/164
International ClassificationG02F1/17, G02B5/30, G02F1/01
Cooperative ClassificationG02F1/172, G02B5/3033, G02B5/3058
European ClassificationG02F1/17A, G02B5/30P2, G02B5/30P1