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WO1996021884A1 - Ecran de visualisation a reseau de guides d'ondes coniques - Google Patents

Ecran de visualisation a reseau de guides d'ondes coniques Download PDF

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Publication number
WO1996021884A1
WO1996021884A1 PCT/US1996/000341 US9600341W WO9621884A1 WO 1996021884 A1 WO1996021884 A1 WO 1996021884A1 US 9600341 W US9600341 W US 9600341W WO 9621884 A1 WO9621884 A1 WO 9621884A1
Authority
WO
WIPO (PCT)
Prior art keywords
waveguides
light
array
display screen
tapered
Prior art date
Application number
PCT/US1996/000341
Other languages
English (en)
Inventor
Michael J. Mcfarland
Scott M. Zimmerman
Karl W. Beeson
James T. Yardley
Paul M. Ferm
Jerry W. Kuper
Original Assignee
Alliedsignal Inc.
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Alliedsignal Inc. filed Critical Alliedsignal Inc.
Priority to AU46969/96A priority Critical patent/AU4696996A/en
Publication of WO1996021884A1 publication Critical patent/WO1996021884A1/fr

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Classifications

    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B21/00—Projectors or projection-type viewers; Accessories therefor
    • G03B21/54—Accessories
    • G03B21/56—Projection screens
    • G03B21/60—Projection screens characterised by the nature of the surface
    • G03B21/62—Translucent screens
    • G03B21/625—Lenticular translucent screens
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/10—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type
    • G02B6/12—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
    • G02B6/122—Basic optical elements, e.g. light-guiding paths
    • G02B6/1221—Basic optical elements, e.g. light-guiding paths made from organic materials
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/10—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type
    • G02B6/12—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
    • G02B6/122—Basic optical elements, e.g. light-guiding paths
    • G02B6/1228—Tapered waveguides, e.g. integrated spot-size transformers
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems

Definitions

  • This invention is directed to an improved display screen for rear projection apparatus as for example, video projectors.
  • this invention relates to such display screens which incorporate arrays of tapered optical waveguides to achieve relatively high light transmission, high contrast, and large viewing angles
  • the diffusing screen is located between the image projector and the audience.
  • the function of such a display screen is to transmit as much of the light from the projector to the audience and at the same time to diffuse the light throughout a large viewing angle.
  • Conventional display screens suffer from a number of inherent disadvantages. For example, at high viewing angles (large angles from the direction normal to the surface of the display), such displays surfer from low contrast and low brightness.
  • Another disadvantage of the prior art is that the display screens do not provide sufficient control over the angular spread of light on the viewing side of the display screen. Such control is highly desireable as it permits efficient utilization of the light which is passing through such a display device. By efficiency, it is understood that the intent is to project the light which comprises the display information into only those angular regions where a viewer is likely to be positioned.
  • image display means for displaying said image, said display means comprising an array of tapered optical waveguides on a planar substrate the tapered end of each of said waveguides extending outward from said substrate and having a light input surface adjacent said substrate and a light output surface distal from said light input surface, wherein:
  • the area of the light input surface of each waveguide is greater than the area of its light output surface, and the center-to-center distance between the light input surfaces of adjacent waveguides in said array is equal to the center-to-center distance between the light output surfaces thereof, so that the angular distribution of light emerging from the output surfaces of the waveguides is larger than the angular distribution of light entering the waveguides;
  • the center to center distance between the adjacent input and output surfaces are not equal in such a way that a portion of the waveguides are tilted to direct the output light towards a particular viewing angle
  • the display device of this invention exhibits several advantages over known devices.
  • the device of this invention has relatively high contrast and reduced changes in brightness as a function of viewing angle.
  • FIG. 1 is a simple schematic illustrating a rear projector and display screen
  • FIG. 2 is an exploded sectional view of an array of tapered waveguides with straight sidewalls.
  • FIG. 3 is an array of tapered waveguides with round cross-sections viewed in perspective.
  • FIG. 4 is an array of tapered waveguides with rectangular cross-sections viewed in perspective.
  • FIG. 5 is an exploded sectional veiw of an array of tapered waveguides where a portion of the waveguides are tilted with respect to the normal of the substrate.
  • FIG. 6 is a sectional view of a single tapered waveguide with straight sidewalls.
  • FIG. 7 shows the theoretical non-imaging optical properties of a single tapered waveguide having straight sidewalls and a taper angle of 4.6°.
  • FIG. 8 shows the theoretical non-imaging optical properties of a single tapered waveguide having straight sidewalls and a taper angle of 8°.
  • FIG. 9 is an exploded sectional view of an array of tapered waveguides with curved sidewalls.
  • FIG. 10 shows one embodiment of the present invention wherein the interstitial regions between waveguides contain an optically absorptive material
  • FIG. 11 shows one embodiment of the present invention wherein the output faces of the waveguide array are covered by a transparent protective layer.
  • FIG. 12 shows a preferred embodiment of the present invention wherein the output faces of the waveguide array are covered by a transparent protective layer incorporating an array of negative lenses.
  • FIG. 13 illustrates a preferred process for the formation of a tapered waveguide array of the present invention. Description of the Preferred Embodiments
  • the invention is directed to a display screen suitable for rear projection systems used in various types of display systems such as radar screens, flight and ship simulators, microfilm readers and rear projection systems for video and cinematographic pictures
  • a display screen suitable for rear projection systems used in various types of display systems such as radar screens, flight and ship simulators, microfilm readers and rear projection systems for video and cinematographic pictures
  • an image is generated in a primary image source and is imaged on the rear projection screen 14 by a system o projection lenses 13, such as a Fresnel lens
  • the display screen spreads the light rays 10 incident from the rear projection means 12 into the viewing space in front of the screen 14 as shown in FIG 1
  • the device of this invention has improved display means which obviates all or portion of the deficiencies of rear projection screens, which among others include, low contrast and low b ⁇ ghtness at high viewing angles, i e large angles from the direction normal to the surface of the display
  • FIG 2 shows an exploded sectional view of image display means 22 for use as a display screen 14 in a rear projection application FIG 2 and the subsequent figures are only illustrative in nature and are not meant to convey dimensional characteristics
  • the image display means is composed of a substrate 24, adhesion promoting layer 26 and an array of tapered waveguides 28
  • the tapered waveguides 28 have a light input surface 30, light output surface 31, sidewalls 32 and are separated by interstitial regions 33 with a lower refractive index than the refractive index of said waveguides
  • Input surface area 30 of each tapered waveguide 28 is positioned adjacent to the adhesion promoting layer 26 and is larger than output surface area 31 of each waveguide 28
  • the optical properties, for example, contrast, viewing angle and change in brightness as a function of viewing angle, of an array of tapered waveguides 28 are determined by the shape, size and physical arrangement of the individual waveguides 28.
  • the area of light input surface 30 of each waveguide 28 is greater than the area of its light output surface 31, and the center- to-center distance between light input surfaces 30 of adjacent waveguides 28 in said array is equal or substantially equal to the center-to-center distance between light output surfaces 31 thereof, so that the angular distribution of light emerging from output surfaces 31 of waveguides 28 is larger than the angular distribution of light entering input surfaces 30 of waveguides 28.
  • the geometric center of output surface 31 aligns with the geometric center of input surface 30 along an optical axis 20 which coincides with the normal to substrate 24.
  • the cross-section of a tapered waveguide 28 in a plane parallel to the surface of image display means 22 may have any shape including a square, a rectangle, any equilateral polygon, a circle or an oval.
  • FIG. 3 shows an array composed of tapered waveguides 28 which have circular cross-sections. In this embodiment, the angular distribution of the light output is increased in symmetrical viewing angles about the horizontal and vertical axes.
  • FIG. 4 shows an array composed of tapered waveguides 28 with rectangular cross-sections viewed in perspective. In this embodiment, the waveguide structures will yield an asymmetric viewing output. Accordingly, the geometry of the tapered waveguide itself is altered so as to result in a greater angular dispersion in one axis than the other.
  • FIGS. 5 A and 5B A further embodiment is shown in FIGS. 5 A and 5B where a portion of the waveguide structures are tilted so that optical axis 20 forms a tilt angle ⁇ with respect to the normal of substrate 24.
  • FIG 5 A illustrates an arrangement applicable for large projection screens where the screen is larger than the viewing angle, and the audience will typically experience a loss in brightness along the edges of the screen. This is due to the fact that the image is being projected away from the viewing audience due to the diffusive characteristics of the screen.
  • the optical axis 20 of a portion of waveguides inwards, or biased towards the center of the screen, the image is directed more towards the viewing angle thereby eliminating a loss of brightness at the edges of the screen.
  • FIG. 5B illustrates an arrangement applicable for small projection screens where the screen is smaller than the viewing angle of the audience.
  • the optical axis 20 of a portion of waveguides outwards, or biased away from the center of the screen the image is directed at a larger viewing angle.
  • waveguides in the center of the display screen would have a zero tilt angle, or , optical axis 20 aligned with the normal to substrate 24, and tilt angle ⁇ of each optical axis increases moving away from the center to the edges of the display screen.
  • the tilt angle ⁇ of individual waveguides would be dependent upon the viewing angle of the audience and the angle of light entering the light input surface.
  • a display screen could have any combination of optical axes 20 aligned with the normal of substrate 24 or directed inwards or away from the center of the display screen.
  • Substrate 24 of waveguide array 22 in FIG. 2 is transparent to light within the wavelength range from about 400 to about 700 nm.
  • the index of refraction of the substrate may range from about 1.45 to about 1.75.
  • the most preferred index of refraction is from about 1.50 to about 1.70.
  • the substrate may be made from any transparent solid material. Preferred materials include transparent polymers, glass and fused silica. Desired characteristics of these materials include mechanical and optical stability at typical operating temperatures of the device. Compared with glass, transparent polymers have the added advantage of structural flexibility which allows display means 22 to be formed in large sheets and then cut as required by the application.
  • 5 are formed from a transparent solid material having a higher index of refraction than the interstitial regions 33 between the waveguides.
  • the operational function of waveguide 28 differs from a lens in that a lens does not utilize total internal reflection
  • the sum of the areas for all waveguide input surfaces 30 be greater than 40% of the total area of substrate 24 of the array. It is more preferred that the sum of the areas for all waveguide input surfaces 30 in image display means 22 be greater than 60% of the total area of substrate 24 of the array. It is most preferred that the sum of the areas for all waveguide input surfaces 30 in image display means 22 be greater than 70% of the total area of substrate 24 of the array.
  • the area of output surface 31 of each waveguide 28 be from about 1 to about 50% of the area of the input surface 30. It is more preferred that the area of the output surface 31 be from about 3 to about 25% of the area of the input surface 30. It is most preferred that the area of output surface 31 be from about 4 to about 15% of the area of input surface 30.
  • Tapered waveguides 28 can be constructed from any transparent solid polymer material.
  • Preferred materials have an index of refraction between about 1.45 and about 1.65 and include polymethylmethacrylate, polycarbonate, polyester, polystyrene and polymers formed by photopolymerization of acrylate monomers More preferred materials have an index of refraction between about 1.50 and about 1.60 and include polymers formed by photopolymerization of acrylate monomer mixtures composed of urethane acrylates and methacrylates, ester acrylates and methacrylates, epoxy acrylates and methacrylates, (poly) ethylene glycol acrylates and methacrylates and vinyl containing organic monomers.
  • Useful monomers include methyl methacrylate, n-butyl acrylate, 2-ethylhexyl acrylate, isodecyl acylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, cyclohexyl acrylate, 1,4-buta ⁇ ediol diacrylate, ethoxylated bisphenol A diacrylate, neopentylglycol diacrylate, diethyleneglycol diacrylate, diethylene glycol dimethacrylate, 1,6- hexanediol diacrylate, trimethylol propane triacrylate, pentaerythritol triacrylate and pentaerythritol tetra-acrylate.
  • the most preferred materials for use in the method of the invention are crosslinked polymers formed by photopolymerizing mixtures of ethoxylated bisphenol A diacrylate and trimethylol propane triacrylate.
  • the index of refraction of the most preferred materials ranges from about 1.53 to about 1.56. It is not essential that the refractive index of the transparent solid material be homogeneous throughout the waveguide element.
  • inhomogeneities in refractive index such as striations or scattering particles or domains
  • these inhomogeneities may further increase the divergence of light from the output of the waveguide array.
  • the index of refraction of interstitial region 33 between the waveguides 28 must be less than the index of refraction of the waveguides.
  • Preferred materials for interstitial regions include air, with an index of refraction of 1.00, and fluoropolymer materials with an index of refraction ranging from about 1.30 to about 1.40.
  • adhesion promotion layer 26 is not critical and can vary widely. Usually, the thickness of the layer is as used in conventional direct view flat panel display devices. In the preferred embodiments of the invention, adhesion promoting layer 26 is less than about 1 micrometer thick.
  • a single tapered waveguide 28 with input surface 30, output surface 31 and straight sidewalls 32 is shown in FIG. 6. If tapered straight sidewalls 32 in the drawing are extended until they intersect, they form taper angle 36. Desired values for taper angle 36 range from about 2 degrees to about 14 degrees. More preferred values for taper angle 36 range from about 4 degrees to about 12 degrees. Most preferred values for taper angle 33 are from about 6 degrees to about 10 degrees.
  • the length of tapered waveguide 28 has dimension 34.
  • Dimension 35 is the mininum transverse distance across waveguide input surface 30. For example, if input surface 30 has the shape of a square, dimension 35 is the length of one side of the square. If input surface 30 has a rectangular shape, dimension 35 is the smaller of the two side dimensions of the rectangle. The specific values for dimension 35 may vary widely depending on the particular application of the display screen. Once dimension 35 is chosen, dimension 34 can be specified by the ratio of dimension 34 to dimension 35. The ratio of dimension 34 to dimension 35 may vary widely depending on how much one wishes to increase the angular distribution of light emerging from the output surface 31 compared to the angular distribution of light entering input surface 30. The ratio of dimension 34 to dimension 35 is usually from about 0.25 to about 20. It is more preferred that the ratio of dimension 34 to dimension 35 be from about 1 to about 15. It is most preferred that the ratio of dimension 34 to dimension 35 be from about 2 to about
  • FIG. 7 shows the output distribution of a particular tapered waveguide assuming an input of 10,000 light rays randomly distributed over the input surface 30 of the cone and randomly distributed over input angles of -10 to +10 degrees.
  • the cone that was modelled in FIG. 7 has a square input surface 30 that is 45 microns on a side, a square output surface 31 that is 25 microns on a side, a length 34 of 125 microns, straight sidewalls 32 and a taper angle 36 of 4.6 degrees.
  • the output area of surface 31 is 31% of the area of input surface 30.
  • the tapered waveguide has improved the light distribution from the input range of -10 to +10 degrees to approximately -30 to +30 degrees.
  • tapeered waveguide 28 has a square input surface 30 that is 45 microns on a side, a square output surface 31 that is 10 microns on a side, a length 34 of 125 microns , straight sidewalls 32 and a taper angle 36 of 8 degrees.
  • the output area of surface 31 is 5% of the area of input surface 30.
  • Using an input light ray distribution of -10 to +10 degrees results in a calculated output distribution of approximately -80 to +80 degrees.
  • the output distribution shown in FIG. 8 is a significant improvement compared to the distribution illustrated in FIG. 7.
  • Image display means 22 is composed of a substrate 24, an adhesion promoting layer 26 and individual tapered waveguides 28 Waveguides 28 have curved sidewalls 38 instead of straight sidewalls as was previously shown in FIG 2
  • the preferred relationships between the area of the output surface 40 and the area of the input surface 39 are the same as the preferred relationships previously stated for tapered waveguides 28 with straight sidewalls
  • the area of output surface 40 of each waveguide 28 be from about 1 to about 50% of the area of input surface 39 It is more preferred that the area of the output surface 40 be from about 3 to about 25% of the area of input surface 39 It is mos preferred that the area of output surface 40 be from about 4 to about 15% of the area of input surface 39.
  • the absorptive material may be a continuous light absorptive material.
  • light absorptive material 41 is contained in a second low refractive index material, such as a fluoropolymer or any other optically clear plastic of low index such as clear silicone.
  • a second low refractive index material such as a fluoropolymer or any other optically clear plastic of low index such as clear silicone.
  • FIG 1 1 A further embodiment of the present invention as shown in FIG 1 1 which incorporates protective layer 42 over output ends of the tapered waveguides 28
  • Protective layer 42 prevents mechanical damage to the output surfaces of waveguides 28 and also serves to confine light absorptive material 41 to interstitial regions 33 between waveguides 28.
  • Protective layer 42 is composed of a transparent backing material 43 as for example the material used to form substrate 24 and optionally and preferably an anti-glare or anti-reflective film 44 formed from a material such as magnesium fluoride, which reduces specular reflections of ambient light from the surface of waveguide array 22.
  • FIG. 12 an embodiment of the present invention is illustrated which utilizes a protective layer 45 which includes an array of negative lenses 46 Each lens 46 is formed on substrate 48 and is optically aligned with the output end 3 lof waveguide 28. Lens 46 is composed of a material with a lower refractive index than the overcoat layer 50. The advantage of incorporating an array of negative lenses with the image display means 22 is that the resulting display will have increased viewing angle.
  • Arrays of tapered optical waveguides can be manufactured by a variety of techniques including injection molding, compression molding, hot roller pressing, embossing, casting, and photopolymerization processes.
  • a preferred technique is a photopolymerization process of co-pending U.S. patent application, serial no 08/148,794, assigned to the same assignee as the present application and incorporated herein by reference.
  • FIG. 13 The photopolymerization method is illustrated in FIG. 13 whereby the tapered waveguides are formed by ultraviolet (UV) light irradiation of a layer of photoreactive monomers through a patterned mask.
  • substrate 24 which is coated with adhesion promoting layer 26 is laminated onto the surface of a partially transparent mask 51.
  • This assembly is placed on top of a layer of photoreactive monomers 52 which, in turn- is placed over a bottom support plate 53 having a release layer 54.
  • Mask 51 bears a pattern of opaque areas 55 which allow UV light 56 (FIG. 13B) to pass through only in the areas which comprise the desired pattern of the array of tapered optical waveguides.
  • Ultraviolet light 56 as from a mercury or xenon lamp, is directed to fall on the surface of the image mask 51.
  • Ultraviolet light which passes through the clear areas of the mask causes a photopolymerization reaction in the regions 57 of monomer layer 52 which are directly under the clear image areas of the mask 51. No photoreaction occurs in those areas of monomer layer 52 which are shielded from the UV light by the opaque areas 55 of image mask 51.
  • both image mask 51 and bottom support plate 53 with release layer 54 are removed (FIG. 13C).
  • Photopolymerized regions 58 correspond to the tapered optical waveguides 28 of the present invention.
  • the optical absorption of the unreacted monomer layer 52 at the wavelengths of the UV light must be high enough such that a gradient of UV light intensity is established through the film during UV light exposure That is, the amount of UV light available in the monomer layer to cause the initiation of the photoreaction will decrease from the top, or the image mask side, towards the bottom, or the bottom support plate side, due to the finite absorption of the monomer layer
  • This gradient of UV light causes a gradient in the amount of photopolymerization reaction that occurs from top to bottom, and this results in the unique tapered geometry of the developed waveguide structures, a geometry which is easily accessible with the method of the present invention
  • the gradient in the amount of photopolymerization which occurs from the top to the bottom of the film may be further influenced by the presence of dissolved oxygen gas in the monomer layer
  • the requisite geometry of the photopolymer structures may be further influenced by the process of self-focussing That is, the light falling on the surface of the monomer layer initiates photopolymerization at that surface, and since the refractive index of the solidified polymer material is higher than that of the liquid monomer, it acts to refract the light passing through it In this manner the aerial image of light falling on the monomer nearer to the bottom of the monomer layer is altered through refraction caused by the already-polyme ⁇ zed material which lies above it This effect may cause a narrowing of the resultant polymerized structure from the top surface, upon which the imaging light was directed, towards the bottom, or support plate side of the layer.
  • a photolithographically created mask (5"x5"x0 09") with a two-dimensional g ⁇ d of 45 micron wide clear squares on 50 micron centers was used The 5 micron wide spaces between squares were opaque to ultraviolet and visible radiation Onto this mask a few drops of methanol were applied and then a 100 micron thick poly(ethylene terephthalate) (PET) film was pressed on.
  • PET film was prepared with an ultra-thin film surface treatment which renders it reactive and adherable to polymerizing monomer solution.
  • Such surface-activated films were known to those skilled in the art. The surface tension of the methanol caused the film to mildly, but firmly adhere to the mask.
  • PET film constituted the array substrate subassembly. Onto a separate 5"x5"x0.25" blank glass plate was bonded a PET film using a pressure sensitive adhesive. This constituted the release film subassembly. The release film subassembly was placed film-side up on a black, metal platform containing threaded holes. Metal spacers, 1 cm x 3 cm x 200 microns thick, were placed around the edges on top of the release film. Approximately 1 milliliter of a photopolymerizable monomer solution was delivered to the center of the release film.
  • This monomer solution consisted of 62 parts ethoxylated bisphenol A diacrylate, 31 parts trimethylolpropane triacrylate, 1 part Irganox 1010 antioxidant, 2 parts Darocure 1173 photoinitiator, 2 parts Irgacure 651 photoinitiator, and 2 parts Irgacure 500 photoinitiator.
  • the array substrate subassembly was then placed, film-side down on top of the monomer solution.
  • a clear glass 5"x5"x0.25" plate was placed on top of this entire fabrication assembly and metal clamps and screws were used to fully and evenly compress the plates together resulting in a 200 micron thick monomer solution layer between the release film and the array substrate.
  • UV-vis ultraviolet/visible
  • the UV-vis system contained a 1000 Watt Mercury-Xenon lamp and delivered even, collimated, and homogeneous full-spectrum radiation with an intensity of 85 mW/c ⁇ r to the entire 5" x 5" area of the fabrication assembly.
  • the sample was irradiated for 0.76 seconds.
  • the fabrication assembly was then dissassembled and the array film with the tapered optical waveguides now formed, but still covered with monomer solution in the interstitial regions between elements, was placed upside-down in a bath of isopropanol and left for ten minutes.
  • Isopropanol was a relatively poor solvent for the monomer but was advantageous since it allowed for the even and mild development of the optical waveguide elements' reflective walls After removal of the the residual monomer, the tapered optical waveguides were dried in a stream of nitrogen gas, placed in a a nitrogen gas-purged enclosure, and hard cured under the UV-vis radiation for an additional 20 seconds.
  • Electron microscopy and optical microscopy were used to evaluate the tapered optical waveguides.
  • the individual optical waveguides were observed to have the shape of truncated right square pyramids.
  • the elements were 200 microns tall.
  • the width of the smaller, output surface of the optical waveguides was 20 microns.
  • the reflective sidewalls were very smooth and joined together at a depth of 160 microns below the output surface face.
  • the input surface of the waveguides was located at the interface between the 100 micron thick PET array substrate and the width of this input surface was 50 microns although, as described, the input surfaces were totally fused together in this example.
  • the taper angle of the optical waveguides was thus 12 degrees.
  • Example 1 above was taken as a starting point.
  • the tapered optical waveguides were abundantly covered with carbon lampblack powder, an optically absorbing material.
  • the lampblack powder had a average particle size much smaller than the 50 micron dimensions of the optical waveguides.
  • the powder was then carefully smoothed into the interstitial regions of the array of tapered optical waveguides using a soft instrument, in this case a gloved finger. The excess was removed with the same instrument.
  • the optical waveguides were so robust that the lampblack could be spread without causing visible damage. Looking at the output side of the tapered waveguide array, the lampblack caused the array to appear a dark, matte black. The percent of the visible surface area which was blackened was determined to be 85 percent.
  • a transmission measurement was carried out by passing a helium-neon laser beam with a gaussian mode shape and a 6 degree full divergence angle through the array of tapered optical waveguides.
  • the transmission was 60%.
  • the optically absorbing material was lampblack powder
  • the powder came in direct contact with only a small fraction of the surface area of the waveguide sidewalls and allowed the phenomenon of total internal reflection to proceed unimpeded.
  • Light was transmitted through the waveguides by entering the input ends of the waveguides, reflecting off the side walls of the waveguides and exiting through the output surfaces.
  • the optically absorbing material was a black epoxy, it index matched to the reflective sidewalls and caused the light to couple through the sidewalls and be absorbed by the optically absorbing material.
  • Example 2 above was taken as a starting point.
  • the array of tapered optical waveguides with interstitial regions filled with lampblack powder was laminated together with a piece of PET film prepared with a pressure sensitive adhesive.
  • the pressure-sensitive adhesive formed an index matched interface with the output surface of the optical waveguides.
  • the array of waveguides continued to show a transmission of 60 percent as in example 2 above.
  • the array of tapered optical waveguides was now fitted with a protective layer and was washed, flexed, and handled without damage to the waveguides and without loss of the powdery, optically absorptive material.
  • Example 2 above was taken as a starting point.
  • the array of tapered optical waveguides with interstitial regions filled with lampblack powder was laminated together with a piece of plastic heat-activated lamination film, typically used to laminate identification cards.
  • the laminating film formed an index matched interface with the output surface of the optical waveguides.
  • the array of waveguides continued to show a transmission of 60 percent as in example 2 above
  • the array of tapered optical waveguides was now fitted with a protective layer and was washed, flexed, and handled without damage to the waveguides and without loss of the powdery, optically absorptive material.
  • Example 4 above was taken as a starting point.
  • the laminated, protective film offered a continuous air-plastic interface which caused light from behind the viewer to be reflected back into the viewer's eye.
  • the example was covered with a layer of the same photopolymerizable monomer solution as used in example 1 above.
  • On top of the array and monomer solution was then placed a glass plate with an anti-reflection coating. After curing the monomer solution with UV-vis radiation, the array of tapered optical waveguides with a protective, laminated plastic film, and a further anti-reflection coated glass plate was observed to appear much darker. This was due to the reduction in reflected spurious light reaching the viewer's eyes.
  • Example 4 above was taken as a starting point.
  • the protected array of tapered optical waveguides with absorptive black material was placed in front of a helium-neon laser beam with a gaussian mode shape and a 6 degree full divergence angle.
  • the laser beam propagated from the light input side to the light output side
  • the light output was then observed on a diffusive viewing screen to be transformed into a broad pattern.
  • This pattern was analyzed using video frame grabbing instrumentation and computer software. Analysis showed that this array of tapered optical waveguides caused light to be transformed into a broad output pattern centered about the central laser beam spot. Due to the use of a single laser beam and the geometry of the waveguides, the output pattern contained four-fold symmetry and 8 spots of roughly equal intensity. The full angular distribution of the regions of maximum spot intensity was 40 degrees. The entire output pattern of the array of tapered waveguides showed a relatively smoothly decreasing variation in light output intensity over a full angle of about 60 degrees even though the laser beam input had only a 6 degree divergence.
  • a lambertian diffuser offered an object to test the absolute display characteristics of the array of tapered optical waveguides.
  • the intensity of the light propagating coUinearly with the laser beam was normalized to 1.
  • the array of tapered optical waveguides provided 50 percent of the intensity of the ideal lambertian diffuser.
  • the array of tapered optical waveguides provided 17 percent of the intensity of the ideal lambertian diffuser. It should be pointed out that the lambertian diffuser operates by a mechanism of intense scattering and transmitted only 47 percent of the light incident on one surface in the forward direction.

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  • Optical Integrated Circuits (AREA)

Abstract

Ecran de visualisation comportant: (a) un réseau de guides d'ondes coniques placés sur un substrat planant, l'extrémité conique desdits guides d'ondes s'éloignant du substrat, leur surface d'entrée de lumière étant adjacente audit substrat, la surface de sortie de lumière étant en position distale par rapport à ladite surface d'entrée de lumière; étant entendu: (i) pour chacun des guides d'onde la surface d'entrée de la lumière est supérieure à celle de sortie, que la distance centre à centre des surfaces d'entrée de guides contigus est égale à celle de leurs surfaces de sortie de lumière si bien que la distribution angulaire de la lumière sortant des surfaces de sortie des guides d'ondes est plus grande que celle de la lumière pénétrant dans les guides d'ondes; (ii) que les guides d'ondes dudit réseau sont séparés par des zones interstitielles d'indice de réfraction inférieur à celui des guides d'ondes.
PCT/US1996/000341 1995-01-12 1996-01-11 Ecran de visualisation a reseau de guides d'ondes coniques WO1996021884A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU46969/96A AU4696996A (en) 1995-01-12 1996-01-11 Display screen device with array of tapered waveguides

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US37164895A 1995-01-12 1995-01-12
US08/371,648 1995-01-12

Publications (1)

Publication Number Publication Date
WO1996021884A1 true WO1996021884A1 (fr) 1996-07-18

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Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US1996/000341 WO1996021884A1 (fr) 1995-01-12 1996-01-11 Ecran de visualisation a reseau de guides d'ondes coniques

Country Status (3)

Country Link
AU (1) AU4696996A (fr)
TW (1) TW284859B (fr)
WO (1) WO1996021884A1 (fr)

Cited By (21)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2002052341A1 (fr) * 2000-12-27 2002-07-04 3M Innovative Properties Company Ecran de projection par transparence microstructure
GB2364791B (en) * 2000-07-14 2004-12-29 Evan Arkas Optical channel plates
KR100470321B1 (ko) * 2004-05-31 2005-02-05 주식회사 세코닉스 흡광물질이 표면에만 코팅된 디스플레이용 광학소자 및 그제조방법
WO2005116740A1 (fr) * 2004-05-31 2005-12-08 Sekonix Co., Ltd. Dispositif optique pour afficheur a guide d'onde a impedance croissante et procede de fabrication associe
WO2005116732A1 (fr) * 2004-05-31 2005-12-08 Sekonix Co., Ltd. Dispositif optique pour un ecran comprenant un guide d'onde a impedance croissante et procede de fabrication
KR100793478B1 (ko) 2002-09-24 2008-01-14 세이코 엡슨 가부시키가이샤 투과형 스크린 및 리어형 프로젝터
EP1751605A4 (fr) * 2004-05-31 2010-04-28 Sekonix Co Ltd Dispositif d'affichage uniformisant la distribution spatiale de la lumiere et procede de fabrication
WO2014120672A3 (fr) * 2013-01-30 2014-09-25 Cree, Inc. Guides d'ondes optiques
US9291320B2 (en) 2013-01-30 2016-03-22 Cree, Inc. Consolidated troffer
US9366799B2 (en) 2013-03-15 2016-06-14 Cree, Inc. Optical waveguide bodies and luminaires utilizing same
US9366396B2 (en) 2013-01-30 2016-06-14 Cree, Inc. Optical waveguide and lamp including same
US9442243B2 (en) 2013-01-30 2016-09-13 Cree, Inc. Waveguide bodies including redirection features and methods of producing same
US9625638B2 (en) 2013-03-15 2017-04-18 Cree, Inc. Optical waveguide body
US9690029B2 (en) 2013-01-30 2017-06-27 Cree, Inc. Optical waveguides and luminaires incorporating same
US9869432B2 (en) 2013-01-30 2018-01-16 Cree, Inc. Luminaires using waveguide bodies and optical elements
US9920901B2 (en) 2013-03-15 2018-03-20 Cree, Inc. LED lensing arrangement
US10209429B2 (en) 2013-03-15 2019-02-19 Cree, Inc. Luminaire with selectable luminous intensity pattern
US10416377B2 (en) 2016-05-06 2019-09-17 Cree, Inc. Luminaire with controllable light emission
US10436970B2 (en) 2013-03-15 2019-10-08 Ideal Industries Lighting Llc Shaped optical waveguide bodies
US11112083B2 (en) 2013-03-15 2021-09-07 Ideal Industries Lighting Llc Optic member for an LED light fixture
US11719882B2 (en) 2016-05-06 2023-08-08 Ideal Industries Lighting Llc Waveguide-based light sources with dynamic beam shaping

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GB1017471A (en) * 1962-06-25 1966-01-19 Wendell Smith Miller Rear projection screen
US3303374A (en) * 1961-01-17 1967-02-07 Litton Prec Products Inc Cathode ray tube including face plate comprising tapered fiber optical elements mounted in an opaque mosaic
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EP0433486A1 (fr) * 1988-06-22 1991-06-26 Bke Bildtechnisches Konstruktions- Und Entwicklungsbüro Inh. Ernst Stechemesser Ecran de projection transparent
EP0491963A1 (fr) * 1990-06-29 1992-07-01 ARSENICH, Svyatoslav Ivanovich Projecteur
EP0518362A1 (fr) * 1991-06-14 1992-12-16 Omron Corporation Dispositif d'affichage d'image utilisant un télé-projecteur à crystaux liquides et réseau d'éléments optiques coniques utilisés dans un tel dispositif

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3303374A (en) * 1961-01-17 1967-02-07 Litton Prec Products Inc Cathode ray tube including face plate comprising tapered fiber optical elements mounted in an opaque mosaic
GB1017471A (en) * 1962-06-25 1966-01-19 Wendell Smith Miller Rear projection screen
US4264130A (en) * 1978-06-20 1981-04-28 Ricoh Co., Ltd. Self-focusing fiber array
EP0433486A1 (fr) * 1988-06-22 1991-06-26 Bke Bildtechnisches Konstruktions- Und Entwicklungsbüro Inh. Ernst Stechemesser Ecran de projection transparent
EP0491963A1 (fr) * 1990-06-29 1992-07-01 ARSENICH, Svyatoslav Ivanovich Projecteur
EP0518362A1 (fr) * 1991-06-14 1992-12-16 Omron Corporation Dispositif d'affichage d'image utilisant un télé-projecteur à crystaux liquides et réseau d'éléments optiques coniques utilisés dans un tel dispositif

Cited By (32)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2364791B (en) * 2000-07-14 2004-12-29 Evan Arkas Optical channel plates
US6928219B2 (en) 2000-07-14 2005-08-09 Ralph Alexander Wimmer Optical channel plates with optical fibers or hollow waveguides
WO2002052341A1 (fr) * 2000-12-27 2002-07-04 3M Innovative Properties Company Ecran de projection par transparence microstructure
US6636355B2 (en) 2000-12-27 2003-10-21 3M Innovative Properties Company Microstructured rear projection screen
KR100793478B1 (ko) 2002-09-24 2008-01-14 세이코 엡슨 가부시키가이샤 투과형 스크린 및 리어형 프로젝터
KR100470321B1 (ko) * 2004-05-31 2005-02-05 주식회사 세코닉스 흡광물질이 표면에만 코팅된 디스플레이용 광학소자 및 그제조방법
WO2005116740A1 (fr) * 2004-05-31 2005-12-08 Sekonix Co., Ltd. Dispositif optique pour afficheur a guide d'onde a impedance croissante et procede de fabrication associe
WO2005116732A1 (fr) * 2004-05-31 2005-12-08 Sekonix Co., Ltd. Dispositif optique pour un ecran comprenant un guide d'onde a impedance croissante et procede de fabrication
US7450814B2 (en) 2004-05-31 2008-11-11 Sekonix Co., Ltd Optical device for a display having tapered waveguide and process for making the same
EP1751605A4 (fr) * 2004-05-31 2010-04-28 Sekonix Co Ltd Dispositif d'affichage uniformisant la distribution spatiale de la lumiere et procede de fabrication
US9519095B2 (en) 2013-01-30 2016-12-13 Cree, Inc. Optical waveguides
US9291320B2 (en) 2013-01-30 2016-03-22 Cree, Inc. Consolidated troffer
US11644157B2 (en) 2013-01-30 2023-05-09 Ideal Industries Lighting Llc Luminaires using waveguide bodies and optical elements
US9366396B2 (en) 2013-01-30 2016-06-14 Cree, Inc. Optical waveguide and lamp including same
US9389367B2 (en) 2013-01-30 2016-07-12 Cree, Inc. Optical waveguide and luminaire incorporating same
US9442243B2 (en) 2013-01-30 2016-09-13 Cree, Inc. Waveguide bodies including redirection features and methods of producing same
WO2014120672A3 (fr) * 2013-01-30 2014-09-25 Cree, Inc. Guides d'ondes optiques
US9581751B2 (en) 2013-01-30 2017-02-28 Cree, Inc. Optical waveguide and lamp including same
US10436969B2 (en) 2013-01-30 2019-10-08 Ideal Industries Lighting Llc Optical waveguide and luminaire incorporating same
US9690029B2 (en) 2013-01-30 2017-06-27 Cree, Inc. Optical waveguides and luminaires incorporating same
US9869432B2 (en) 2013-01-30 2018-01-16 Cree, Inc. Luminaires using waveguide bodies and optical elements
US9920901B2 (en) 2013-03-15 2018-03-20 Cree, Inc. LED lensing arrangement
US10209429B2 (en) 2013-03-15 2019-02-19 Cree, Inc. Luminaire with selectable luminous intensity pattern
US9625638B2 (en) 2013-03-15 2017-04-18 Cree, Inc. Optical waveguide body
US10436970B2 (en) 2013-03-15 2019-10-08 Ideal Industries Lighting Llc Shaped optical waveguide bodies
US11112083B2 (en) 2013-03-15 2021-09-07 Ideal Industries Lighting Llc Optic member for an LED light fixture
US9366799B2 (en) 2013-03-15 2016-06-14 Cree, Inc. Optical waveguide bodies and luminaires utilizing same
US10416377B2 (en) 2016-05-06 2019-09-17 Cree, Inc. Luminaire with controllable light emission
US10527785B2 (en) 2016-05-06 2020-01-07 Ideal Industries Lighting Llc Waveguide-based light sources with dynamic beam shaping
US10890714B2 (en) 2016-05-06 2021-01-12 Ideal Industries Lighting Llc Waveguide-based light sources with dynamic beam shaping
US11372156B2 (en) 2016-05-06 2022-06-28 Ideal Industries Lighting Llc Waveguide-based light sources with dynamic beam shaping
US11719882B2 (en) 2016-05-06 2023-08-08 Ideal Industries Lighting Llc Waveguide-based light sources with dynamic beam shaping

Also Published As

Publication number Publication date
TW284859B (fr) 1996-09-01
AU4696996A (en) 1996-07-31

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