CA2024541C - Reverse light blocking hologram for a center high mounted stoplight - Google Patents
Reverse light blocking hologram for a center high mounted stoplightInfo
- Publication number
- CA2024541C CA2024541C CA002024541A CA2024541A CA2024541C CA 2024541 C CA2024541 C CA 2024541C CA 002024541 A CA002024541 A CA 002024541A CA 2024541 A CA2024541 A CA 2024541A CA 2024541 C CA2024541 C CA 2024541C
- Authority
- CA
- Canada
- Prior art keywords
- stoplight
- vehicle
- illumination
- holographic
- assembly
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
- 230000000903 blocking effect Effects 0.000 title claims abstract description 47
- 238000005286 illumination Methods 0.000 claims abstract description 64
- 230000003405 preventing effect Effects 0.000 claims abstract description 10
- 238000003384 imaging method Methods 0.000 claims description 13
- 230000004044 response Effects 0.000 claims description 5
- 238000010276 construction Methods 0.000 description 22
- 230000004224 protection Effects 0.000 description 17
- 230000008901 benefit Effects 0.000 description 4
- 230000005540 biological transmission Effects 0.000 description 4
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- 238000000034 method Methods 0.000 description 4
- 230000000712 assembly Effects 0.000 description 2
- 238000000429 assembly Methods 0.000 description 2
- 230000003247 decreasing effect Effects 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 240000001973 Ficus microcarpa Species 0.000 description 1
- 108010010803 Gelatin Proteins 0.000 description 1
- 229920006385 Geon Polymers 0.000 description 1
- 241000034673 Holographis Species 0.000 description 1
- XDXHAEQXIBQUEZ-UHFFFAOYSA-N Ropinirole hydrochloride Chemical compound Cl.CCCN(CCC)CCC1=CC=CC2=C1CC(=O)N2 XDXHAEQXIBQUEZ-UHFFFAOYSA-N 0.000 description 1
- 238000009825 accumulation Methods 0.000 description 1
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- 230000000593 degrading effect Effects 0.000 description 1
- 230000009977 dual effect Effects 0.000 description 1
- 229920000159 gelatin Polymers 0.000 description 1
- 239000008273 gelatin Substances 0.000 description 1
- 108010025899 gelatin film Proteins 0.000 description 1
- 235000019322 gelatine Nutrition 0.000 description 1
- 235000011852 gelatine desserts Nutrition 0.000 description 1
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Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60Q—ARRANGEMENT OF SIGNALLING OR LIGHTING DEVICES, THE MOUNTING OR SUPPORTING THEREOF OR CIRCUITS THEREFOR, FOR VEHICLES IN GENERAL
- B60Q1/00—Arrangement of optical signalling or lighting devices, the mounting or supporting thereof or circuits therefor
- B60Q1/26—Arrangement of optical signalling or lighting devices, the mounting or supporting thereof or circuits therefor the devices being primarily intended to indicate the vehicle, or parts thereof, or to give signals, to other traffic
- B60Q1/44—Arrangement of optical signalling or lighting devices, the mounting or supporting thereof or circuits therefor the devices being primarily intended to indicate the vehicle, or parts thereof, or to give signals, to other traffic for indicating braking action or preparation for braking, e.g. by detection of the foot approaching the brake pedal
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B5/00—Optical elements other than lenses
- G02B5/32—Holograms used as optical elements
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60Q—ARRANGEMENT OF SIGNALLING OR LIGHTING DEVICES, THE MOUNTING OR SUPPORTING THEREOF OR CIRCUITS THEREFOR, FOR VEHICLES IN GENERAL
- B60Q1/00—Arrangement of optical signalling or lighting devices, the mounting or supporting thereof or circuits therefor
- B60Q1/26—Arrangement of optical signalling or lighting devices, the mounting or supporting thereof or circuits therefor the devices being primarily intended to indicate the vehicle, or parts thereof, or to give signals, to other traffic
- B60Q1/30—Arrangement of optical signalling or lighting devices, the mounting or supporting thereof or circuits therefor the devices being primarily intended to indicate the vehicle, or parts thereof, or to give signals, to other traffic for indicating rear of vehicle, e.g. by means of reflecting surfaces
- B60Q1/302—Arrangement of optical signalling or lighting devices, the mounting or supporting thereof or circuits therefor the devices being primarily intended to indicate the vehicle, or parts thereof, or to give signals, to other traffic for indicating rear of vehicle, e.g. by means of reflecting surfaces mounted in the vicinity, e.g. in the middle, of a rear window
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
- G03H1/00—Holographic processes or apparatus using light, infrared or ultraviolet waves for obtaining holograms or for obtaining an image from them; Details peculiar thereto
- G03H1/22—Processes or apparatus for obtaining an optical image from holograms
- G03H1/2202—Reconstruction geometries or arrangements
Abstract
A REVERSE LIGHT BLOCKING HOLOGRAM FOR A
CENTER HIGH MOUNTED STOPLIGHT
ABSTRACT OF THE DISCLOSURE
A rear window mounted stoplight assembly for a vehicle including stoplight illuminating apparatus for producing stoplight illumination, and a scatter blocking hologram adjacent the stoplight illuminating apparatus for preventing scattered stoplight illumination from being viewable by the vehicle operator. In a particular embodi-ment, the stoplight illumination apparatus includes an image volume hologram and a source of playback illumina-tion.
CENTER HIGH MOUNTED STOPLIGHT
ABSTRACT OF THE DISCLOSURE
A rear window mounted stoplight assembly for a vehicle including stoplight illuminating apparatus for producing stoplight illumination, and a scatter blocking hologram adjacent the stoplight illuminating apparatus for preventing scattered stoplight illumination from being viewable by the vehicle operator. In a particular embodi-ment, the stoplight illumination apparatus includes an image volume hologram and a source of playback illumina-tion.
Description
2~2~
A ~EVERSE ~IGHT BLOCKING ~IOLOGRAM FOR A
CENTER HIGH MOUNTED STOPLIGHT
1 ~ACRGROUND OF Tl-lE INV~.NTION
The disclosed invention generally relates to center-hl~h mounted brake lights or stoplights fo.r vehicles, and S more particularly is directed to a center high mounted stoplight assembly which includes a scatter blocking holographic structure for preventing scattere~ stoplight illumination from being viewable i.n the rearward field of view of the vehicle operator.
Present Federal regulations require center high mounted stoplights in automobiles i.n addition to the traditional stoplights. Tlle high mounted stopliyhts are intended to maximi~e the visibility of the stoplights to following drivers.
: 15 Center high mounted stopli~hts have been implemented : as a standard lenticuIar lens and an illuminating i.ncan-: descent bulb enclosed in a housing that is commonly secured adjacent the top or bottom of an automobi].e rear window (al.so referred ko as an automobi.le back].ight). The bul]cy housing, which is i.ntended to prevent scattered stoplight illumination from being within the driver's ; rearward field of view, partially obscures rearward visibility, imposes limitations or. design, and is gener-ally unattractive. Further, the bulky housing can create the startling impression that a vehicle is follow.ing cl.ose hehind. An~ although the hulky housing is intended to prevent scattered stoplight illumination from entering the automobile, it is not completely effective, particularly if the backlight is dirty and/or covered with moisture or snow.
In order to avoid the visibility obscuration of the bulb and lens center high mount~ed stoplight, holographic stoplight systems have been developed wherein holograms secured to the automobile backlight provide stoplight illumination when illuminated with playback illumination.
The holograms are substantially transparent to the driver's rearward field of view, and the playback illumination source is outside such field of view, which avoids the obscuration presented by the bulb and lens type stoplight assemblies. Examples of center high mounted holographic stoplights are disclosed in U.S. Patent No. 4,892,369, issued January 9, 1990, for ~Holographic Rear Window Stoplight," which is assigned to assignee of the subject application.
However, holographic stoplight systems, like the bulb and lens type stoplight assemblies, produce unwanted scattering into the automobile of stoplight illumination when the backlight is dirty and/or covered with moisture or snow. Further, recording imperfections and recording material properties cause the hologram itself to scatter playback illumination into the automobile.
The forward scattering of stoplight playback and imaging illumination may be sufficiently intense a~ to be unacceptable unless the stoplight illumination intensity is reduced, which may result in an unacceptably low intensity.
SUMMARY OF THE INVENTION
It would therefore be an advantage to provide a center high mounted stoplight for a vehicle which prevents scattered stoplight illumination from being viewable by the operator of the vehicle.
.
r Another advantage would be to provide a center high mounted stoplight for a vehicle which is substantially transparent to the rearward vision of the vehicle operator and which prevents scattered stoplight illumination from being viewable by the operator of the vehicle.
The foregoing and other advantages are provided by the invention in a rear stoplight assembly for a vehicle which includes a stoplight holographic structure for producing a stoplight image in response to playback illumination and a source o~ playback illumination. A scatter blocking holographic structure adjacent the stoplight holographic structure prevents scattered stoplight playback and imaging illumination from being viewable by the vehicle operator.
Other aspects of this invention are as follows:
A rear stoplight assembly ~or a vehicle having a rear window, comprising:
stoplight means adjacent the rear window for producing stoplight illumination; and holographic scatter blocking means for preventing scattered stoplight illumination from being viewable by the vehicle operator, said hologram scatter means being substantially transparent to the rearward vision of the operator of the vehicle.
A rear stoplight assembly for a vehicle having a rear window, comprising:
holographic stoplight imaging means secured to the rear window for producing stoplight illumination in response to playback illumination;
means for providing playback illumination for said holographic imaging means; and holographic scatter blocking means for transmitting said playback illumination to said holographic imaging means for preventing scattered stoplight illumination from being viewable by tne vehicle operator, said holographic scatter blocking means being substantially transparent to the rearward vision of the operator of the vehicle.
":: .. ; ::, , : ~. . : i. :, , . . .. : .
3a A rear stoplight assembly for a vehicle having a rear window, comprising:
stoplight means adjacent the rear window for producing stoplight illumination; and a volume reflection hologram in the proximity of said stoplight means for preventing scattered stoplight illumination from being viewable by the vehicle operator, said volume reflection hologram being substantially transparent to the rearward vision of the operator of the vehicle.
A light emitting display comprising:
means for providing display image illumination directed generally in a first direction; and holographic scatter blocking means for preventing scattered display illumination from being directed generally in a second direction.
BRIEF DESCRIPTION OF THE DRAWINGS
The advantages and features of the disclosed invention will readily be appreciated by persons skilled in the art from the following detailed description when read in conjunction with the drawings wherein:
FIG. 1 is a schematic elevational view of a stoplight assembly in accordance with the invention.
FIG. 2 is a schematic perspective view depicting the ~ ;
geometrical considerations involved in the construction of a scatter blocking hologram for the stoplight assembly of FIG. l.
FIG. 3 is a schematic illustration of an illustrative example of the construction of a scatter blocking `
.
1 holo~ram for the stoplight ac~semb.ly of FIG. l w.i.~h a collimated construction reference beam.
FIG. ~ is a schematic illustration of another illustrative example of the construction of a scatter blocking hologram for the stoplight assembly of FIG.
with a diverging constr~lction reference beam.
FIG. 5 is a schematic elevational view o~ a further stoplight assembly in accordance with the invent.ion.
DETAILED DESCRIPTION OF T~E ~ISCTJOSUR~
In the following detailefl description and in the several ~igures of the drawing, li.l;e elements are i.den-tified with like reference numerals.
Referring now to FIG. 1, shown therei.n is a stop-light assembly for a vehicle which includes a stopligh-t holographic structure 11 supported by the rear window 13 of the vehicle or by a suitable substantially transparent su~strate. By way of specific example, the stoplight holographic structure 11 can comprise a single volume hologram having one or more holograms recorded therein, or a plurality of volume holograms arranged i.n laminar fashion, wherein each volume hologram has one or more holograms recorded therein.
A scatter blocking holographic structure 15 is secured to the non-supported side o:E the holographi.c structure 11, and transmits playback illumi.nation to the holographic structure 11 ~rom an illumination source 17 located above and forward o~ the composite holographic structures. The scatter blocking holbgraphic structure 15 can comprise a single volume hologram having one or more holograms recorded therein, or a plurality of volume holograms arranged in laminar fashion, wherein each volume ~ hologram has one or more holograms recorded therein.
:.
.. .. . .. . .. . ~ ... ., , ~ . .. .. .. . . .... ... . .
1 In response to ~ e pl.ayba(~lc :i.J.J.umi.na~.i.on, llle stoplight holographic i~tructure 11 produces stopligh~
illumination that is dir~cted ~eneralJ.y rearwardly ~rom the vehicle (to tha right in ~.he elevati.onal view of FIG.
1).
While the holographic structure 11 i.s shown as beinq conflgured for receiving playback illumination from a light source ].ocated above ancl forward of the holographic structure, other holographic playback struc-tures couJ.d be utilized, includlng an edge .illuminated hol.ogram or a re-flection hologram illumi.nated by a source locatecl a~ove and behind the hologram, The scatter bloc]cincJ hologri~phi.c structure l5 is coextensive with or can overlap the stop]ight holographic structure 11, and is adapted to prevent scattered stop-light imagin~ and playbac]c illumina~,i.on from being view-able within rearwar~ field of view of the vehicle opera-tor. Such scattered 8toplight imagin~ illuminal:ion can be caused by an accumulation of dirt 19 on the rear window 13, or by moisture or snow on the rear window 13, Eor example; and scattered playback illumina-tion can caused by noise and recording imperfections in the holographic structure, for example.
The considerations involved in the construction of the scatter blocking holographic structure 15 can be better understood by reference to FIG. 2, which schemat-ically illustrates ~he complex scatter protectlon volumes in which light scattered from the stoplight holographic structure 11 can pose a problem for the vehicle operator.
Such scatter protection volumes are defined by the collec-tion of rays from all points on the stoplight holographic structure 11 to all points in the areas A and B, where the area A includes the po~ential locations of the operator's eyes looking directly to the rear of the vehicle (i~e., the rearward view eyehox), and the area B is ~he ~area of , .. . .. . . .. . . . . . ........... . .
, . .. , , , . ~- . ~.... . , :.-, . , ........ ,~
1 t~e rearview mirror~ l)epenc~.l.n~ on veh.i~].e confi.~ rLI~ioll~
the respective scatter protection volumes definefl by the areas A and B could overlapping or non-overlapping.
Generally~ the scattered light will be of suffic-iently low intensity that secondary scat-ter into the vehicle from beams outside the scatter protection volumes can be ignored. However, it would be prudent to establish for each vehlcle coniguration that such beams outside the scatter protection volumes do not reflect into the opera-- 10 tor's eyes ~rom specular surfaces such as the windshield.
Ideally, for each polnt on the stopli.ght holocJraphic structure 11, the scatter blocking holographia structure 15 would be optimized for the scattering rays from that point which could be within the scatter protection vol-umes. Such optimization would include maximizing the reflectance of each point on the scatter bloc~ing holo-graphic structure that would potentially receive scattered light rays that would be within the scatter protecti.on volumes. This would be achieved by controlling, as to each point on the scatter blocking holographic structure, : the construction reference beam ray to be cen-tered in the volume defined by the scatter rays within -the scatter protection volumes that could pass through such poin-t.
~owever, practical considerations in the construction of : 25 the scatter blocking holographic structure 15 on].y permit : ~ that such ideal be approached to varying de~rees. For example, the construction wavefronts can be chosen planar for simplicity of generation, or complex aspheric for better performance.
The following discussion is directed to i.llustrative examples of constructing volume holograms for the scatter blocking holographic structure 15, and for ease of dis-cusslon scatter points on the stoplight holographic structure will be considered as being adjacent the ho].o-gram being recorded.
, i.
1 neferring now to Fl:G. 3, schelnat:Lcally depicted therein is an illustrative example of the construction of a volume hologram for the scatter bloc]cing holographic structure lS with a collimated reference construction beam having parallel rays, part.icularly for the scatter pro-tec-tion volume defined by the rearward viewing area ~. A
hologram recording med;.um 115, dichromated gelatin ~or exam~le, .is exposed to a collimated reference beam RB that is incident on the right side of the record;.ng medillln 115 at an angle e2 and an object beam OB that is incident on the left side of the recording medi.um 115 at an any].e el.
The object beam, which determines the direction in :;
which the intercepted scattered light will be direc-ted, can be a collimated beam or a converging beam, as desired.
With a converging beam, the hologram can be designed so as to direct the intercepted scattered light to a region that has been determined to be non-reflective, for example.
The extreme ray angles relative to the viewing area A are illustrated for the scatter points Pl, P2, PN. The points Pl and PN are located at the edgPs of the recorcling medium 115 while P2 i5 located generally in the center of the recording medium. ~s an illustrative example, the reference beam direction is selected to bisect the extreme ray angle for the scatter point P2, as illustrated by the construction reference beam ray C2, which provides the best match for the average scattering ray direction through the scatter point P2. However, as illustrated by the construction beam rays Cl and CN through the scatter points Pl and PN at the edges oP the recording medium, the construction beam direction i9 far from most of the scattering rays through such points. Thls lack of match-ing with the scattering rays requires an increase in the angular banclwidth of the scatter blocking hologram being constructed, with the attendant loss of see-through clarity. : --1 The relationsh~p hetween tlle angles ~ 2 ~eter-mlnes whether the scatter blocking hologram fringes are slanted or unslantedr with the ~ringes being unslanted .i.f the angles are equal. A scatter blocking hologram having unslanted fringes advanta~eously cloes not act as a trans-mission grating, which avoicls the rainhow effect around bright li~hts as viewed through the scatte~ blockin~
hologram.
For various considerations, it may be more appropr.i-ate to have unequal angles e1, e2, in which case theresulting holo~ram will act as a transmission grat~ng that produces the rainbow effect around bright lights viewed through the guard hologram. Such considerations would include the desired direction of reflection of the scat-tered light that is intercepted, or to compensate forthose geometrical cases wherein spurious li~h-t, such as sunlight, could reflect off an unslanted scatter h].ocking hologram .in a direction such that ~lass surface reflec-tions co~lld turn on the stoplight holograph.ic structure.
Also, the slanted fringe can be used as a means to narrow the angular and wavelength bandwidth of the scatter blocking hologram, thereby improving see-through or transparency to the stoplight playback illumination.
It is noted that the rainbow e~fect resulting from slanted fringes can be reduced by techniques such as those disclosed in U.S. Patent 4,815,800.
Referring now to FIG. 4, schematically depicted therein is an illustrative example of the construction of a scatter blocking volume hologram with a converging construction reference beam. In particular, the reference beam is controlled to provide construction beam rays that generally/bisect the scattering ray fans for each of the scatter, as illustrated by the rays C1, C2, CN throllgh the points Pl, P2, PN, which points are generally the same as the points so identified in FIG. 3. This control of the 1 constructi.on rays minim:i~e~ the clevia~i.on Oe -tlle ex~rellle rays at e~ch scatter point from the direction of the construction reference beam ray, ensuring maximum protec-tion for a given see~through.
In general~ the xesulting requi.red con~truction reference beam wavefront for a converging beam will be a complex function requiring spe~ial aspheric optics for its precise generation. ~owever, the construction reference beam wavefront need not be very precise, and considerable improvement relative to a collimated reerence heam can be achieved with simple spherical opt:Lcs or cylindrical elements. As an example, a simple converging wavefront easi]y made with a spherical lens could approximate the required construction ray directions.
As with the recording process depicted in FIG. 3, a collimated or converging object heam can he u-tilized in the recording process of FIG. 4. Also, a converging beam might be utilized to produce fringes that are close to being unslanted.
The foregoing construction considerations also apply to the scatter protection volume defined by the rear view mirror area B. Depending on the overlap or non-overlap of the scatter protection volumes and the amount of separa-tion, if any, a separate hologram could be constructed for25 each of the scatter protection volumes. Alternatively, a single hologram could be constructed with the reference beam appropriately directed to produce the required scatter ray interception. Also, the single volume holo-gram could be recorded with multiple exposures for the ~ifferent scatter protection volumes. Recording a single hologram to cover both scatter protection volumes can be more complex than recording separate holograms for differ-ent scatter protection volumes.
A scatter blocking hologram recorded pursuant to the foregoing would be oriented in the scatter blocking 1 holographic structure so as to be oriented ln an auto-mobile in the same orientation as exposed, with the re~erence beam incident si.de toward the stoplight holo-graphic structure 11.
It should be appreciated that the particulars o~ the scatter blocking holographic structure wi.ll depe~d greatly on the geon~etry of the vahicle with which it i9 to he utilized, as well as other factors including the size of the driver's eyebox, the distance between the operator and the rear window, the slant of the rear window, the loca-tion of the playback source, and the size, shape and location of the stoplight of the stoplight holographic structure. Other considerations include the required see-through transmission and the bandwidth of the playback illumination. The effects of these factors include the following.
The angular range over which the scatter blocking holographic structure must provide protection is deter-mined by the size of the rearward view eyebox and the distance from the eyebox to the rear window. In particu-lar, the angular range of protection increases with increasing eyebox size and with decreasing distance to the rear window.
As the slant of the rear window rakes more from vertical, the scattered light that is directed to the driver ~which is close to horizontal) is at an angle that departs considerably from normal relative to the scatter i blocking holographic structure. For unslanted fringes, this decxeases the angular bandwidth of the scatter blocking holographic structure, which requires that the thickness of the hologram elements thereof be decreased to regain the necessary angu].ar bandwidth. Reducing thick-ness in turn requires an increase .in the recorded refrac-tive index change to maintain diffraction ef~iciency.
Alternatively, for highly raked rear windows, slant fringe 1 holograms could be utili~.ed to keep the fringe an~les close to normal relative to the scattered light within the scatter protection volumes, and additional means could be utilized to suppxess the rainbow effect due to the slant fringes.
As to the location of the playbac]c source for the stoplight holographic structure, the direction of the reference beam utilized in constructin~ the scatter hlocking holographic structure must be selected to insure that the scatter bloc]cing hologram i8 substantially transparenk to the playback illumination. In particular, the reference beams utili~ed in constructing the scatter blocking holographic structure and the stoplight holo~
graphic structure should be at different effective ang]es, taking into account angular shifts due to processing the recording medium and differences in construction and playback wavelengths.
As to the size o~ the scatter blocking holographic structure, it was previously stated that it preferably overlaps the stoplight holographic structure. This is to match any overlapping of the illumination ~eam or scatter from around the edges of the stoplight holographic struc-ture.
As to the playback souxce brightness, if the souxce is sufficiently bright, it can be filtered to a narrow band that meets the spectral requirements Eor the stop-light illumination, which in turn narrows the required wave ength bandwidth for the scatter blocking holographic structure. This allows more selective angular cutof~, reducing the angular difference needed ~or high playback illumination transmission and high scattexed light xeflec-tion. The choice of construction heam angles bPcomes less constrained and and design optimi~ation is easier.
As to see-through requirements, the light scattered 3S by a stoplight holographic stxucture can xeduce see 1 through at night if ~here is no scatt:er l~l.ocki.n~ holo-graphic structure. The need to prevent see-tllroucJll reduction sets the limit on the resi.dual scattered li.ght that can be tolerated and therefore the attenuation specifications for the scatter b].ock.ing holographic structure. It should be noted that the allowable see-through degradation varies with location on the rear window. For example, see-through must be ~etter in the center of the rear window than for the extreme hottom through which only the sur~ace of the rear deck migllt be visih].e. Si.milar considerations appJ.y in dayli.gllt cona.l-tions for haziness or other see-through degrading optical.
phenomena.
As to the bandwidth of the playback illumination, the bandwidth of the scatter blocking holographic should be as wide as the playhack illumination since the scat-tered light, which must ba rejected hy the scatter block-ing holographic structure, has the same bandwidth as the playback illumination.
A typical scatter blockin~ holographic structure might require an angular bandwidth of 10 degrees for an eyebox of 12 inches across and iocated 70 inches ahead of the rear window. A rejection ratio or 100 to 1 can be readily achieved over thi.s angular bandwidth with known hologram recording techniques for dichromated gelatin film with a satisfactory wavelength bandwidth for a red fil-tered incandescent ~toplight holographic structure.
Lar~er angular bandwidths for smaller vehicles will involve some compromise in rejection ratio relative to angular bandwidth and/or wavelength bandwidth. The compromise might be a stoplight holographic structure having a narrower wavelength bandwidth, which would require a more powerful playback illumination source to maintain stoplight brightness.
While the scatl:er blocklng holocJraphic s~ucture llas been described primarily in the conte~t o~ a h~lographic stoplight structure, it should be appreciated that the scatter blocking holographic structure can be utilized with a traditional rear window stoplight assembly as shown in FIG. 5 for intercepting scattered stoplight illumina-tion caused by dirt, moisture, or snow on the rear window.
Such stoplight assem~ly includes, for example, a red filter lenticular len3 and an incandescent bulb ~n a housing con~igured to be against the rear window, po~sibly with a ~asket. By way of ill~lskrative example, the scatter blocking holographic structure would be secured to rear window to extend over an area that is larger than the rear window area adjacent the stoplight housing. Alter-natively, the scatter blocking holographic structure could configured to be secure~ to the rear window area that surrounds the stoplight housing.
The foregoing has been a disclosure of a center high mounted stoplight assembly for a vehicle which prevents scattered stoplight illumination from being within the rearward field of view of the vehicle operator. When embodied with a holographic stoplight structure, the stoplight emitting structure is advantageously substan-tially transparent.
Although the foregoing has been a description and illustration of specific embodiments of the invention, various modifications and changes thereto can be made by persons skilled in the art without departing from the scope and spirit of the invention as defined by the following claims.
A ~EVERSE ~IGHT BLOCKING ~IOLOGRAM FOR A
CENTER HIGH MOUNTED STOPLIGHT
1 ~ACRGROUND OF Tl-lE INV~.NTION
The disclosed invention generally relates to center-hl~h mounted brake lights or stoplights fo.r vehicles, and S more particularly is directed to a center high mounted stoplight assembly which includes a scatter blocking holographic structure for preventing scattere~ stoplight illumination from being viewable i.n the rearward field of view of the vehicle operator.
Present Federal regulations require center high mounted stoplights in automobiles i.n addition to the traditional stoplights. Tlle high mounted stopliyhts are intended to maximi~e the visibility of the stoplights to following drivers.
: 15 Center high mounted stopli~hts have been implemented : as a standard lenticuIar lens and an illuminating i.ncan-: descent bulb enclosed in a housing that is commonly secured adjacent the top or bottom of an automobi].e rear window (al.so referred ko as an automobi.le back].ight). The bul]cy housing, which is i.ntended to prevent scattered stoplight illumination from being within the driver's ; rearward field of view, partially obscures rearward visibility, imposes limitations or. design, and is gener-ally unattractive. Further, the bulky housing can create the startling impression that a vehicle is follow.ing cl.ose hehind. An~ although the hulky housing is intended to prevent scattered stoplight illumination from entering the automobile, it is not completely effective, particularly if the backlight is dirty and/or covered with moisture or snow.
In order to avoid the visibility obscuration of the bulb and lens center high mount~ed stoplight, holographic stoplight systems have been developed wherein holograms secured to the automobile backlight provide stoplight illumination when illuminated with playback illumination.
The holograms are substantially transparent to the driver's rearward field of view, and the playback illumination source is outside such field of view, which avoids the obscuration presented by the bulb and lens type stoplight assemblies. Examples of center high mounted holographic stoplights are disclosed in U.S. Patent No. 4,892,369, issued January 9, 1990, for ~Holographic Rear Window Stoplight," which is assigned to assignee of the subject application.
However, holographic stoplight systems, like the bulb and lens type stoplight assemblies, produce unwanted scattering into the automobile of stoplight illumination when the backlight is dirty and/or covered with moisture or snow. Further, recording imperfections and recording material properties cause the hologram itself to scatter playback illumination into the automobile.
The forward scattering of stoplight playback and imaging illumination may be sufficiently intense a~ to be unacceptable unless the stoplight illumination intensity is reduced, which may result in an unacceptably low intensity.
SUMMARY OF THE INVENTION
It would therefore be an advantage to provide a center high mounted stoplight for a vehicle which prevents scattered stoplight illumination from being viewable by the operator of the vehicle.
.
r Another advantage would be to provide a center high mounted stoplight for a vehicle which is substantially transparent to the rearward vision of the vehicle operator and which prevents scattered stoplight illumination from being viewable by the operator of the vehicle.
The foregoing and other advantages are provided by the invention in a rear stoplight assembly for a vehicle which includes a stoplight holographic structure for producing a stoplight image in response to playback illumination and a source o~ playback illumination. A scatter blocking holographic structure adjacent the stoplight holographic structure prevents scattered stoplight playback and imaging illumination from being viewable by the vehicle operator.
Other aspects of this invention are as follows:
A rear stoplight assembly ~or a vehicle having a rear window, comprising:
stoplight means adjacent the rear window for producing stoplight illumination; and holographic scatter blocking means for preventing scattered stoplight illumination from being viewable by the vehicle operator, said hologram scatter means being substantially transparent to the rearward vision of the operator of the vehicle.
A rear stoplight assembly for a vehicle having a rear window, comprising:
holographic stoplight imaging means secured to the rear window for producing stoplight illumination in response to playback illumination;
means for providing playback illumination for said holographic imaging means; and holographic scatter blocking means for transmitting said playback illumination to said holographic imaging means for preventing scattered stoplight illumination from being viewable by tne vehicle operator, said holographic scatter blocking means being substantially transparent to the rearward vision of the operator of the vehicle.
":: .. ; ::, , : ~. . : i. :, , . . .. : .
3a A rear stoplight assembly for a vehicle having a rear window, comprising:
stoplight means adjacent the rear window for producing stoplight illumination; and a volume reflection hologram in the proximity of said stoplight means for preventing scattered stoplight illumination from being viewable by the vehicle operator, said volume reflection hologram being substantially transparent to the rearward vision of the operator of the vehicle.
A light emitting display comprising:
means for providing display image illumination directed generally in a first direction; and holographic scatter blocking means for preventing scattered display illumination from being directed generally in a second direction.
BRIEF DESCRIPTION OF THE DRAWINGS
The advantages and features of the disclosed invention will readily be appreciated by persons skilled in the art from the following detailed description when read in conjunction with the drawings wherein:
FIG. 1 is a schematic elevational view of a stoplight assembly in accordance with the invention.
FIG. 2 is a schematic perspective view depicting the ~ ;
geometrical considerations involved in the construction of a scatter blocking hologram for the stoplight assembly of FIG. l.
FIG. 3 is a schematic illustration of an illustrative example of the construction of a scatter blocking `
.
1 holo~ram for the stoplight ac~semb.ly of FIG. l w.i.~h a collimated construction reference beam.
FIG. ~ is a schematic illustration of another illustrative example of the construction of a scatter blocking hologram for the stoplight assembly of FIG.
with a diverging constr~lction reference beam.
FIG. 5 is a schematic elevational view o~ a further stoplight assembly in accordance with the invent.ion.
DETAILED DESCRIPTION OF T~E ~ISCTJOSUR~
In the following detailefl description and in the several ~igures of the drawing, li.l;e elements are i.den-tified with like reference numerals.
Referring now to FIG. 1, shown therei.n is a stop-light assembly for a vehicle which includes a stopligh-t holographic structure 11 supported by the rear window 13 of the vehicle or by a suitable substantially transparent su~strate. By way of specific example, the stoplight holographic structure 11 can comprise a single volume hologram having one or more holograms recorded therein, or a plurality of volume holograms arranged i.n laminar fashion, wherein each volume hologram has one or more holograms recorded therein.
A scatter blocking holographic structure 15 is secured to the non-supported side o:E the holographi.c structure 11, and transmits playback illumi.nation to the holographic structure 11 ~rom an illumination source 17 located above and forward o~ the composite holographic structures. The scatter blocking holbgraphic structure 15 can comprise a single volume hologram having one or more holograms recorded therein, or a plurality of volume holograms arranged in laminar fashion, wherein each volume ~ hologram has one or more holograms recorded therein.
:.
.. .. . .. . .. . ~ ... ., , ~ . .. .. .. . . .... ... . .
1 In response to ~ e pl.ayba(~lc :i.J.J.umi.na~.i.on, llle stoplight holographic i~tructure 11 produces stopligh~
illumination that is dir~cted ~eneralJ.y rearwardly ~rom the vehicle (to tha right in ~.he elevati.onal view of FIG.
1).
While the holographic structure 11 i.s shown as beinq conflgured for receiving playback illumination from a light source ].ocated above ancl forward of the holographic structure, other holographic playback struc-tures couJ.d be utilized, includlng an edge .illuminated hol.ogram or a re-flection hologram illumi.nated by a source locatecl a~ove and behind the hologram, The scatter bloc]cincJ hologri~phi.c structure l5 is coextensive with or can overlap the stop]ight holographic structure 11, and is adapted to prevent scattered stop-light imagin~ and playbac]c illumina~,i.on from being view-able within rearwar~ field of view of the vehicle opera-tor. Such scattered 8toplight imagin~ illuminal:ion can be caused by an accumulation of dirt 19 on the rear window 13, or by moisture or snow on the rear window 13, Eor example; and scattered playback illumina-tion can caused by noise and recording imperfections in the holographic structure, for example.
The considerations involved in the construction of the scatter blocking holographic structure 15 can be better understood by reference to FIG. 2, which schemat-ically illustrates ~he complex scatter protectlon volumes in which light scattered from the stoplight holographic structure 11 can pose a problem for the vehicle operator.
Such scatter protection volumes are defined by the collec-tion of rays from all points on the stoplight holographic structure 11 to all points in the areas A and B, where the area A includes the po~ential locations of the operator's eyes looking directly to the rear of the vehicle (i~e., the rearward view eyehox), and the area B is ~he ~area of , .. . .. . . .. . . . . . ........... . .
, . .. , , , . ~- . ~.... . , :.-, . , ........ ,~
1 t~e rearview mirror~ l)epenc~.l.n~ on veh.i~].e confi.~ rLI~ioll~
the respective scatter protection volumes definefl by the areas A and B could overlapping or non-overlapping.
Generally~ the scattered light will be of suffic-iently low intensity that secondary scat-ter into the vehicle from beams outside the scatter protection volumes can be ignored. However, it would be prudent to establish for each vehlcle coniguration that such beams outside the scatter protection volumes do not reflect into the opera-- 10 tor's eyes ~rom specular surfaces such as the windshield.
Ideally, for each polnt on the stopli.ght holocJraphic structure 11, the scatter blocking holographia structure 15 would be optimized for the scattering rays from that point which could be within the scatter protection vol-umes. Such optimization would include maximizing the reflectance of each point on the scatter bloc~ing holo-graphic structure that would potentially receive scattered light rays that would be within the scatter protecti.on volumes. This would be achieved by controlling, as to each point on the scatter blocking holographic structure, : the construction reference beam ray to be cen-tered in the volume defined by the scatter rays within -the scatter protection volumes that could pass through such poin-t.
~owever, practical considerations in the construction of : 25 the scatter blocking holographic structure 15 on].y permit : ~ that such ideal be approached to varying de~rees. For example, the construction wavefronts can be chosen planar for simplicity of generation, or complex aspheric for better performance.
The following discussion is directed to i.llustrative examples of constructing volume holograms for the scatter blocking holographic structure 15, and for ease of dis-cusslon scatter points on the stoplight holographic structure will be considered as being adjacent the ho].o-gram being recorded.
, i.
1 neferring now to Fl:G. 3, schelnat:Lcally depicted therein is an illustrative example of the construction of a volume hologram for the scatter bloc]cing holographic structure lS with a collimated reference construction beam having parallel rays, part.icularly for the scatter pro-tec-tion volume defined by the rearward viewing area ~. A
hologram recording med;.um 115, dichromated gelatin ~or exam~le, .is exposed to a collimated reference beam RB that is incident on the right side of the record;.ng medillln 115 at an angle e2 and an object beam OB that is incident on the left side of the recording medi.um 115 at an any].e el.
The object beam, which determines the direction in :;
which the intercepted scattered light will be direc-ted, can be a collimated beam or a converging beam, as desired.
With a converging beam, the hologram can be designed so as to direct the intercepted scattered light to a region that has been determined to be non-reflective, for example.
The extreme ray angles relative to the viewing area A are illustrated for the scatter points Pl, P2, PN. The points Pl and PN are located at the edgPs of the recorcling medium 115 while P2 i5 located generally in the center of the recording medium. ~s an illustrative example, the reference beam direction is selected to bisect the extreme ray angle for the scatter point P2, as illustrated by the construction reference beam ray C2, which provides the best match for the average scattering ray direction through the scatter point P2. However, as illustrated by the construction beam rays Cl and CN through the scatter points Pl and PN at the edges oP the recording medium, the construction beam direction i9 far from most of the scattering rays through such points. Thls lack of match-ing with the scattering rays requires an increase in the angular banclwidth of the scatter blocking hologram being constructed, with the attendant loss of see-through clarity. : --1 The relationsh~p hetween tlle angles ~ 2 ~eter-mlnes whether the scatter blocking hologram fringes are slanted or unslantedr with the ~ringes being unslanted .i.f the angles are equal. A scatter blocking hologram having unslanted fringes advanta~eously cloes not act as a trans-mission grating, which avoicls the rainhow effect around bright li~hts as viewed through the scatte~ blockin~
hologram.
For various considerations, it may be more appropr.i-ate to have unequal angles e1, e2, in which case theresulting holo~ram will act as a transmission grat~ng that produces the rainbow effect around bright lights viewed through the guard hologram. Such considerations would include the desired direction of reflection of the scat-tered light that is intercepted, or to compensate forthose geometrical cases wherein spurious li~h-t, such as sunlight, could reflect off an unslanted scatter h].ocking hologram .in a direction such that ~lass surface reflec-tions co~lld turn on the stoplight holograph.ic structure.
Also, the slanted fringe can be used as a means to narrow the angular and wavelength bandwidth of the scatter blocking hologram, thereby improving see-through or transparency to the stoplight playback illumination.
It is noted that the rainbow e~fect resulting from slanted fringes can be reduced by techniques such as those disclosed in U.S. Patent 4,815,800.
Referring now to FIG. 4, schematically depicted therein is an illustrative example of the construction of a scatter blocking volume hologram with a converging construction reference beam. In particular, the reference beam is controlled to provide construction beam rays that generally/bisect the scattering ray fans for each of the scatter, as illustrated by the rays C1, C2, CN throllgh the points Pl, P2, PN, which points are generally the same as the points so identified in FIG. 3. This control of the 1 constructi.on rays minim:i~e~ the clevia~i.on Oe -tlle ex~rellle rays at e~ch scatter point from the direction of the construction reference beam ray, ensuring maximum protec-tion for a given see~through.
In general~ the xesulting requi.red con~truction reference beam wavefront for a converging beam will be a complex function requiring spe~ial aspheric optics for its precise generation. ~owever, the construction reference beam wavefront need not be very precise, and considerable improvement relative to a collimated reerence heam can be achieved with simple spherical opt:Lcs or cylindrical elements. As an example, a simple converging wavefront easi]y made with a spherical lens could approximate the required construction ray directions.
As with the recording process depicted in FIG. 3, a collimated or converging object heam can he u-tilized in the recording process of FIG. 4. Also, a converging beam might be utilized to produce fringes that are close to being unslanted.
The foregoing construction considerations also apply to the scatter protection volume defined by the rear view mirror area B. Depending on the overlap or non-overlap of the scatter protection volumes and the amount of separa-tion, if any, a separate hologram could be constructed for25 each of the scatter protection volumes. Alternatively, a single hologram could be constructed with the reference beam appropriately directed to produce the required scatter ray interception. Also, the single volume holo-gram could be recorded with multiple exposures for the ~ifferent scatter protection volumes. Recording a single hologram to cover both scatter protection volumes can be more complex than recording separate holograms for differ-ent scatter protection volumes.
A scatter blocking hologram recorded pursuant to the foregoing would be oriented in the scatter blocking 1 holographic structure so as to be oriented ln an auto-mobile in the same orientation as exposed, with the re~erence beam incident si.de toward the stoplight holo-graphic structure 11.
It should be appreciated that the particulars o~ the scatter blocking holographic structure wi.ll depe~d greatly on the geon~etry of the vahicle with which it i9 to he utilized, as well as other factors including the size of the driver's eyebox, the distance between the operator and the rear window, the slant of the rear window, the loca-tion of the playback source, and the size, shape and location of the stoplight of the stoplight holographic structure. Other considerations include the required see-through transmission and the bandwidth of the playback illumination. The effects of these factors include the following.
The angular range over which the scatter blocking holographic structure must provide protection is deter-mined by the size of the rearward view eyebox and the distance from the eyebox to the rear window. In particu-lar, the angular range of protection increases with increasing eyebox size and with decreasing distance to the rear window.
As the slant of the rear window rakes more from vertical, the scattered light that is directed to the driver ~which is close to horizontal) is at an angle that departs considerably from normal relative to the scatter i blocking holographic structure. For unslanted fringes, this decxeases the angular bandwidth of the scatter blocking holographic structure, which requires that the thickness of the hologram elements thereof be decreased to regain the necessary angu].ar bandwidth. Reducing thick-ness in turn requires an increase .in the recorded refrac-tive index change to maintain diffraction ef~iciency.
Alternatively, for highly raked rear windows, slant fringe 1 holograms could be utili~.ed to keep the fringe an~les close to normal relative to the scattered light within the scatter protection volumes, and additional means could be utilized to suppxess the rainbow effect due to the slant fringes.
As to the location of the playbac]c source for the stoplight holographic structure, the direction of the reference beam utilized in constructin~ the scatter hlocking holographic structure must be selected to insure that the scatter bloc]cing hologram i8 substantially transparenk to the playback illumination. In particular, the reference beams utili~ed in constructing the scatter blocking holographic structure and the stoplight holo~
graphic structure should be at different effective ang]es, taking into account angular shifts due to processing the recording medium and differences in construction and playback wavelengths.
As to the size o~ the scatter blocking holographic structure, it was previously stated that it preferably overlaps the stoplight holographic structure. This is to match any overlapping of the illumination ~eam or scatter from around the edges of the stoplight holographic struc-ture.
As to the playback souxce brightness, if the souxce is sufficiently bright, it can be filtered to a narrow band that meets the spectral requirements Eor the stop-light illumination, which in turn narrows the required wave ength bandwidth for the scatter blocking holographic structure. This allows more selective angular cutof~, reducing the angular difference needed ~or high playback illumination transmission and high scattexed light xeflec-tion. The choice of construction heam angles bPcomes less constrained and and design optimi~ation is easier.
As to see-through requirements, the light scattered 3S by a stoplight holographic stxucture can xeduce see 1 through at night if ~here is no scatt:er l~l.ocki.n~ holo-graphic structure. The need to prevent see-tllroucJll reduction sets the limit on the resi.dual scattered li.ght that can be tolerated and therefore the attenuation specifications for the scatter b].ock.ing holographic structure. It should be noted that the allowable see-through degradation varies with location on the rear window. For example, see-through must be ~etter in the center of the rear window than for the extreme hottom through which only the sur~ace of the rear deck migllt be visih].e. Si.milar considerations appJ.y in dayli.gllt cona.l-tions for haziness or other see-through degrading optical.
phenomena.
As to the bandwidth of the playback illumination, the bandwidth of the scatter blocking holographic should be as wide as the playhack illumination since the scat-tered light, which must ba rejected hy the scatter block-ing holographic structure, has the same bandwidth as the playback illumination.
A typical scatter blockin~ holographic structure might require an angular bandwidth of 10 degrees for an eyebox of 12 inches across and iocated 70 inches ahead of the rear window. A rejection ratio or 100 to 1 can be readily achieved over thi.s angular bandwidth with known hologram recording techniques for dichromated gelatin film with a satisfactory wavelength bandwidth for a red fil-tered incandescent ~toplight holographic structure.
Lar~er angular bandwidths for smaller vehicles will involve some compromise in rejection ratio relative to angular bandwidth and/or wavelength bandwidth. The compromise might be a stoplight holographic structure having a narrower wavelength bandwidth, which would require a more powerful playback illumination source to maintain stoplight brightness.
While the scatl:er blocklng holocJraphic s~ucture llas been described primarily in the conte~t o~ a h~lographic stoplight structure, it should be appreciated that the scatter blocking holographic structure can be utilized with a traditional rear window stoplight assembly as shown in FIG. 5 for intercepting scattered stoplight illumina-tion caused by dirt, moisture, or snow on the rear window.
Such stoplight assem~ly includes, for example, a red filter lenticular len3 and an incandescent bulb ~n a housing con~igured to be against the rear window, po~sibly with a ~asket. By way of ill~lskrative example, the scatter blocking holographic structure would be secured to rear window to extend over an area that is larger than the rear window area adjacent the stoplight housing. Alter-natively, the scatter blocking holographic structure could configured to be secure~ to the rear window area that surrounds the stoplight housing.
The foregoing has been a disclosure of a center high mounted stoplight assembly for a vehicle which prevents scattered stoplight illumination from being within the rearward field of view of the vehicle operator. When embodied with a holographic stoplight structure, the stoplight emitting structure is advantageously substan-tially transparent.
Although the foregoing has been a description and illustration of specific embodiments of the invention, various modifications and changes thereto can be made by persons skilled in the art without departing from the scope and spirit of the invention as defined by the following claims.
Claims (16)
1. A rear stoplight assembly for a vehicle having a rear window, comprising:
stoplight means adjacent the rear window for producing stoplight illumination; and holographic scatter blocking means for prevent-ing scattered stoplight illumination from being viewable by the vehicle operator, said hologram scatter means being substantially transparent to the rearward vision of the operator of the vehicle.
stoplight means adjacent the rear window for producing stoplight illumination; and holographic scatter blocking means for prevent-ing scattered stoplight illumination from being viewable by the vehicle operator, said hologram scatter means being substantially transparent to the rearward vision of the operator of the vehicle.
2. The stoplight assembly of Claim 1 wherein said stop light means comprises:
holographic imaging means adjacent the rear window for producing a stoplight image in response to playback illumination; and means for providing playback illumination to said holographic imaging means.
holographic imaging means adjacent the rear window for producing a stoplight image in response to playback illumination; and means for providing playback illumination to said holographic imaging means.
3. The vehicle stoplight assembly of Claim 2 wherein said holographic scatter blocking means comprises a reflection volume hologram for reflecting the scattered stoplight illumination away from the interior of the vehicle.
4. The stoplight assembly of Claim 3 wherein said reflection volume hologram is recorded with a converging reference beam.
5. The vehicle stoplight assembly of Claim 3 wherein said reflection volume hologram is laminarly secured to said holographic imaging means.
6. The vehicle stoplight assembly of Claim 5 wherein said reflection volume hologram is configured to transmit said playback illumination to said holographic imaging means.
7. The vehicle stoplight assembly of Claim wherein said stoplight means comprises:
a housing;
a light source located within said housing; and a stoplight lens responsive to said light source for producing stoplight illumination.
a housing;
a light source located within said housing; and a stoplight lens responsive to said light source for producing stoplight illumination.
8. The vehicle stoplight assembly of Claim 7 wherein said holographic scatter blocking means comprises a reflection volume hologram for reflecting scattered stoplight illumination away from the interior of the vehicle.
9. The vehicle stoplight assembly of Claim wherein said stoplight lens is adjacent the rear window of the vehicle, and wherein said reflection volume hologram is interposed between said stoplight lens and the rear window.
10. The vehicle stoplight assembly of Claim 8 wherein said stoplight lens is adjacent the rear window of the vehicle, and said reflection hologram is secured to the rear window over an area beyond the rear window area occupied by said stoplight lens.
11. A rear stoplight assembly for a vehicle having a rear window, comprising:
holographic stoplight imaging means secured to the rear window for producing stoplight illumination in response to playback illumination;
means for providing playback illumination for said holographic imaging means; and holographic scatter blocking means for trans-mitting said playback illumination to said holo-graphic imaging means for preventing scattered stop-light illumination from being viewable by the vehicle operator, said holographic scatter blocking means being substantially transparent to the rear-ward vision of the operator of the vehicle.
holographic stoplight imaging means secured to the rear window for producing stoplight illumination in response to playback illumination;
means for providing playback illumination for said holographic imaging means; and holographic scatter blocking means for trans-mitting said playback illumination to said holo-graphic imaging means for preventing scattered stop-light illumination from being viewable by the vehicle operator, said holographic scatter blocking means being substantially transparent to the rear-ward vision of the operator of the vehicle.
12. The rear stoplight assembly of Claim 11 wherein said holographic stoplight imaging means comprises a volume hologram, and wherein said holographic scatter blocking means comprises a reflection volume hologram laminarly secured to said volume hologram for reflection the scattered stoplight illumination away from the inter-ior of the vehicle.
13. The stoplight assembly of Claim 12 wherein said scatter blocking reflection volume hologram is recorded with a converging reference beam.
14. A rear stoplight assembly for a vehicle having a rear window, comprising:
stoplight means adjacent the rear window for producing stoplight illumination; and a volume reflection hologram in the proximity of said stoplight means for preventing scattered stoplight illumination from being viewable by the vehicle operator, said volume reflection hologram being substantially transparent to the rearward vision of the operator of the vehicle.
stoplight means adjacent the rear window for producing stoplight illumination; and a volume reflection hologram in the proximity of said stoplight means for preventing scattered stoplight illumination from being viewable by the vehicle operator, said volume reflection hologram being substantially transparent to the rearward vision of the operator of the vehicle.
15. The stoplight assembly of Claim 14 wherein said volume reflection hologram is recorded with a converging reference beam.
16. A light emitting display comprising:
means for providing display image illumination directed generally in a first direction; and holographic scatter blocking means for prevent-ing scattered display illumination from being directed generally in a second direction.
means for providing display image illumination directed generally in a first direction; and holographic scatter blocking means for prevent-ing scattered display illumination from being directed generally in a second direction.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US414,969 | 1989-09-29 | ||
| US07/414,969 US4966426A (en) | 1989-09-29 | 1989-09-29 | Reverse light blocking hologram for a center high mounted stoplight |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2024541A1 CA2024541A1 (en) | 1991-03-30 |
| CA2024541C true CA2024541C (en) | 1994-12-13 |
Family
ID=23643790
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002024541A Expired - Fee Related CA2024541C (en) | 1989-09-29 | 1990-09-04 | Reverse light blocking hologram for a center high mounted stoplight |
Country Status (7)
| Country | Link |
|---|---|
| US (1) | US4966426A (en) |
| EP (1) | EP0420229B1 (en) |
| JP (1) | JPH0733132B2 (en) |
| KR (2) | KR910006085A (en) |
| CA (1) | CA2024541C (en) |
| DE (1) | DE69004912T2 (en) |
| MX (1) | MX169669B (en) |
Families Citing this family (19)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5186533A (en) * | 1990-01-30 | 1993-02-16 | Nissan Motor Co., Ltd. | Lamp arrangement for motor vehicle |
| US5106174A (en) * | 1990-04-16 | 1992-04-21 | Hughes Aircraft Company | Ideal distribution CHMSL hologram with double exposure technique |
| US5243449A (en) * | 1990-12-13 | 1993-09-07 | Hughes Aircraft Company | Ambient turn-on suppression hologram |
| US5138470A (en) * | 1990-12-14 | 1992-08-11 | Hughes Aircraft Company | Guard holograms |
| JP2768560B2 (en) * | 1990-12-28 | 1998-06-25 | セントラル硝子株式会社 | Holographic display device |
| JPH0516726A (en) * | 1991-07-11 | 1993-01-26 | Nissan Motor Co Ltd | Lighting fixture for vehicle |
| US5341230A (en) * | 1992-12-22 | 1994-08-23 | Hughes Aircraft Company | Waveguide holographic telltale display |
| US5383039A (en) * | 1992-12-22 | 1995-01-17 | Hughes Aircraft Company | Focused illumination, reduced light leakage floodlit center high mounted stoplight |
| US5347435A (en) * | 1992-12-22 | 1994-09-13 | Hughes Aircraft Company | Linear lamp holographic trapped beam center high mounted stoplight |
| DE4411440A1 (en) * | 1993-03-31 | 1994-10-06 | Koito Mfg Co Ltd | Holographic stop light (brake light), mounted high, for vehicles |
| JPH0714407A (en) * | 1993-06-24 | 1995-01-17 | Koito Mfg Co Ltd | Lighting apparatus for vehicle |
| US5488493A (en) * | 1993-11-01 | 1996-01-30 | Hughes Aircraft Company | Holographic CHMSL including a hologram assembly and a refractive element laminarly attached thereto for diverging zero order beam |
| EP0653649A1 (en) * | 1993-11-15 | 1995-05-17 | Hughes Aircraft Company | Multiple format holographic CHMSLs |
| FR2728519A1 (en) * | 1994-12-26 | 1996-06-28 | Peugeot | ARRANGEMENT OF AN ADDITIONAL SIGNALING LIGHT IN THE REAR BECQUET OF A MOTOR VEHICLE |
| US5571277A (en) * | 1995-06-12 | 1996-11-05 | General Motors Corporation | Automotive holographic signal lamp |
| US5774241A (en) * | 1996-01-29 | 1998-06-30 | Hughes Aircraft Company | Converging beam holographic decklit CHMSL |
| US5917622A (en) * | 1996-02-08 | 1999-06-29 | Demco Technologies, Inc. | Light device with holographic optics |
| DE102011012520A1 (en) * | 2011-02-26 | 2012-08-30 | GM Global Technology Operations LLC (n. d. Ges. d. Staates Delaware) | Third brake light for motor vehicle, has holographic optical element for refraction and/or reflection incident light beams of light source |
| DE102014119326A1 (en) * | 2014-12-22 | 2016-06-23 | Covestro Deutschland Ag | Lighting device for vehicles |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3665392A (en) * | 1970-08-24 | 1972-05-23 | John T Annas | Vehicle driver-actuated safety signal light assembly |
| US4245882A (en) * | 1977-11-04 | 1981-01-20 | Environmental Research Institute Of Michigan | Doubly modulated on-axis thick hologram optical element |
| US4613200A (en) * | 1984-07-09 | 1986-09-23 | Ford Motor Company | Heads-up display system with holographic dispersion correcting |
| US4610499A (en) * | 1984-11-01 | 1986-09-09 | The United States Of America As Represented By The Secretary Of The Air Force | Diffraction diffusion screen with holographically suppressed zero-order beam |
| US4815800A (en) * | 1984-12-21 | 1989-03-28 | Hughes Aircraft Company | Flare reduction in holograms |
| US4854674A (en) * | 1985-02-27 | 1989-08-08 | Hughes Aircraft Company | Process for improving holographic efficiency |
| US4892369A (en) * | 1987-01-06 | 1990-01-09 | Hughes Aircraft Company | Holographic rear window stoplight |
| US4916593A (en) * | 1989-01-04 | 1990-04-10 | Hughes Aircraft Company | Remotely illuminated transparent holographic stoplight for automobiles |
-
1989
- 1989-09-29 US US07/414,969 patent/US4966426A/en not_active Expired - Lifetime
-
1990
- 1990-09-04 CA CA002024541A patent/CA2024541C/en not_active Expired - Fee Related
- 1990-09-27 DE DE69004912T patent/DE69004912T2/en not_active Expired - Fee Related
- 1990-09-27 EP EP90118548A patent/EP0420229B1/en not_active Expired - Lifetime
- 1990-09-28 KR KR1019900015599A patent/KR910006085A/en not_active Application Discontinuation
- 1990-09-28 JP JP26035190A patent/JPH0733132B2/en not_active Expired - Lifetime
- 1990-09-28 MX MX022624A patent/MX169669B/en unknown
-
1993
- 1993-11-04 KR KR2019930022971U patent/KR940001144Y1/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| DE69004912T2 (en) | 1994-06-23 |
| DE69004912D1 (en) | 1994-01-13 |
| KR910006085A (en) | 1991-04-27 |
| KR940001144Y1 (en) | 1994-03-07 |
| JPH0733132B2 (en) | 1995-04-12 |
| US4966426A (en) | 1990-10-30 |
| JPH03125641A (en) | 1991-05-29 |
| EP0420229B1 (en) | 1993-12-01 |
| MX169669B (en) | 1993-07-16 |
| EP0420229A1 (en) | 1991-04-03 |
| CA2024541A1 (en) | 1991-03-30 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKLA | Lapsed |