Abstract: A volume phase type hologram film has a diffraction grating recorded in a film composed mainly of poly(N-vinylcarbazole). The poly(N-vinylcarbazole) as the main component has a weight-average molecular weight of not less than 1,000,000 and a molecular weight distribution of not more than 3. In the poly(N-vinylcarbazole), the content of a fraction of poly(N-vinylcarbazole) having a weight-average molecular weight of not more than 200,000 does not exceed 1% by weight.

Abstract: A volume phase type hologram has a diffraction lattice recorded in a poly(N-vinyl carbazole) polymer layer where the diffraction lattice is recorded throughout the thickness direction of the polymer layer. A method for preparing the volume phase type hologram has the steps of exposing a photosensitive polymer layer provided on a substrate to an interference pattern; subjecting the polymer layer having been exposed to a first development treatment with a first organic solvent; and peeling the polymer layer off the substrate and subjecting the polymer to a second development treatment with a second organic solvent preferentially from the face that had been in contact with the substrate.

Abstract: A decorative promotional display signage and its method of manufacture includes the steps for combining the constituent elements of the signage, and the resultant combination of these elements. The signage includes a clear transparent substrate with an informational image created on the posterior surface of the substrate by selectively depositing transparent colored inks on this surface. Clear ink may also be deposited on selected portions of the posterior surface of the substrate to emphasize the informational image. A sheet of holographic film, to present a variable color cast to the image, is adhered to the substrate with the layers of ink positioned between the substrate and the holographic film.

Abstract: A novel photocrosslinkable polymeric system has been developed for processing into films having stable second-order nonlinear optical properties. In the present system, polymers bearing photo-crosslinkable chromophores, such as polyvinylcinnamate and are reacted with appropriately designed nonlinear optical molecules with the cinnamate or other photocrosslinkable functionalities for photocrosslinking at one, two or more points. The system can be poled and photocrosslinked in the poled state to yield a material with stable optical nonlinearity and large electro-optic coefficients.

Abstract: In processes of holography using bacteriorhodopsin-based recording media, it is essential to design the signal-to-noise ratio to be as favorable as possible. This is achieved by recording the hologram using circularly polarized light and reconstructing the hologram by using linearly polarized light, specific beam components being selected as a function of polarization in the beam path of the reconstructed hologram. The process is suitable both for purely holographic applications and also for other processes which include one or more intermediate or partial steps involving holography.

Abstract: A holographic recording material consisting of diethylene glycol-bis(allyl carbonate), 2,2-bis[3,5-dibromo-4-(2-methacryloyloxyethoxy)phenyl]propane, and a photopolymerization initiator. A method for holographic recording, which comprises interposing the holographic recording material between two opposed surface materials, heating the interposed holographic recording material thereby solidifying the recording material and giving rise to a dry plate, and then exposing the dry plate to a coherent light.

Abstract: A hologram efficiency adjusting process that includes scanning the brightness effect of a hologram, which is either the hologram to be adjusted or a hologram representative of the hologram to be adjusted, to provide brightness vs. position information. The brightness information is utilized to produce a variable duty cycle half-tone mask that contains a pattern defining the areas of the hologram which are to be removed, with the pattern being unresolvable by the viewer of the hologram from which holograms have been removed pursuant to the mask pattern. The hologram to be adjusted is then photoresist coated and etched in accordance with the mask. Alternatively, the brightness information can be utilized to directly expose, for example by a laser scanner, photoresist disposed on the hologram to be adjusted.

Abstract: The method involves directing first and second separate illuminating beams towards a photosensitive film from separate fixed apparent beam source positions respectively in such a manner that the beams are caused to overlap at the point of incidence at the photosensitive film. Stationary interference fringes are generated and the beams are caused to scan in a raster type pattern over the photosensitive film in such a manner whereby overlapping of the beams is maintained throughout the exposure of the film. The apparatus in one embodiment involves the generation of a third illuminating beam which is used to control means to control an associated scanner to effect synchronised movement of the second beam with the first beam. A further embodiment involves memorising the scanning movement of beam in a memory and using the memorised scanning pattern to control the scanner to maintain beam overlap.

Abstract: A new method for making holographic notch filters in the near infrared spectral region is disclosed. This method utilizes lthe nonlinearity in the response function of holographic materials. When a holographic medium is exposed to two laser beams at different wavelengths, the nonlinearity in the response function causes the formation of notch reflections at wavelengths corresponding to the sum and difference frequencies of the exposing beams. The notch at the difference frequency can be in the NIR region by properly choosing the exposure wavelengths. This method is applicable to holographic filters on both flat and curved substrates.

Abstract: Composite holograms are disclosed wherein microvoids between the holographic interference fringes are filled with a liquid crystal. The diffraction efficiency and other holographic properties of such composite holograms may be varied by external stimuli, e.g., application of an electric field of thermal energy.

Abstract: A passivated dichromated gelatin film in which the film includes a glassy oxide network to provide passivation and structural strengthening. The glassy oxide network is formed simultaneously with the gelatin formation via a sol-gel process.

Abstract: The process is disclosed for altering the wavelength response of a volume phase reflection hologram by contacting the hologram with a diffusion element containing a monomer. Monomer in the diffusion element is partially polymerized to effect a desired diffusion pattern.

Abstract: A method is disclosed for forming a multi-layer holographic device 22. A first hologram is formed on a major surface of a substrate 14. The first hologram is desensitized to prevent interaction with a second subsequently formed hologram. The second hologram is formed conterminous with said first hologram.

Abstract: A decorative multi-colored material and method of making same using rainbow gratings simultaneously evidence different color patterns which change through the color spectrum. The patterns are formed from separate impressions from different portions of a common rainbow grating to provide color differentiation. The multi-colored material may be used for a variety of applications, for example, decorative package wrappings, stickers, product enhancement and the like.

Abstract: A method of and apparatus for forming a volume type phase hologram comprising the steps of, after exposure of a holographic material comprising a polymeric matrix having a radiation active substance associated therewith to an interference pattern of radiation, dipping the pattern-wise exposed holographic material in a swelling solution consisting of a first solvent which can act as a good solvent for the polymer of the matrix and a second solvent which can act as a poor solvent for the polymer and has a higher boiling point than that of the first solvent, and then pulling the swollen holographic material up from the swelling solution, whereby uniformly developed holograms having a large size and high qualities can be easily produced by a simple production process.

Abstract: A holographic mirror is made by a process of continuous exposure. For this purpose, a photosensitive layer (10) is exposed strip by strip in a direction crosswise to that in which the layer is exposed by two interfering beams (6, 6'). Film (11) bearing photosensitive layer (10) is continuously moved in the longitudinal direction (F) at a speed that ensures sufficient exposure of the layer. The procedure makes it possible to produce holograms of any length in one direction.

Abstract: A method for processing exposed holograms to enhance their thermal stability and enable them to withstand a windshield lamination process is disclosed. The secondary processing procedure entails an optional step of applying a moisture barrier to the hologram, followed by heat stabilizing the hologram and storing it in a relatively low humidity environment. Specifically, the exposed holographic material is heated to a peak temperature of about 135.degree. C. and thereafter cooled to provide a thermally stabilized holographic material that maintains its holographic qualities over a relatively broad range of temperatures.

Abstract: This invention relates to a method and apparatus for exposing a photosensitive film on a holographic plate to fabricate a reflective holographic optical element. The apparatus incorporates compensating means which are adapted to compensate for the effects of refractive index shift of the film due to refractive index variations during the exposure process. In one form of the apparatus, a hologram-mirror arrangement is placed on a table on an accurately controlled stepper motor rotating stage so that the table is progressively tilted. In an alternative arrangement the angle of the exposing radiation beam is changed and directed on to the stationary hologram-mirror arrangement. Where a tuneable holographic filter is required where the exposure angle varies over the hologram aperture angular shift is achieved by simple lateral and linear shift of the hologram. The compensating means can also comprise an arrangement for progressively changing the wavelength of the exposing radiation beam.

Abstract: A diffraction grating is created in the branching region of a photopolymer waveguide, preferably by directing onto the branching region coherent light through a hologram of a grating or by intersecting two or more coherent light beams on the branching region in a regular grating pattern.

Abstract: Solid photopolymerizable compositions and photosensitive elements are provided that are useful in preparing optical elements, and especially holograms. The compositions contains a polymeric binder, a liquid ethylenically unsaturated monomer, and a photoinitiator system. Typical compositions have a refractive index modulation of at least 0.005 when measured per the specified test.

Abstract: A new class of sensitizers for photopolymerizable compositions is disclosed derived from cyclic ketones and tricyclic aminoaldehydes. A preferred compound is cyclopentanone, 2.

Abstract: The present invention comprises hologram combiners that incorporate one of several compositions of material to seal their perimeters and prevent the hologram from being attacked by water. The design of the combiner edge seals are fabricated using a perimeter edge buildup technique. The invention is implemented by the use of a band of polymer film, or a metal film such as aluminum foil, for example, that is adhered to the edge of periphery of the combiner. Adhesion is achieved by the use of a adhesive material that has been filled with a water absorbing material comprising molecular sieves such as crystalline aluminosilicate, zeolites, or calcium oxide. Calculations and accelerated static testing have indicated that the present invention provides for a hologram combiner that meets the most stringent environmental requirements, and is suitable for substantially all applications in which it may be employed.

Abstract: The invention relates to a laminated glass panel incorporating therein a hologram sheet. For example, the laminated glass panel is a vehicle windshield in which the hologram sheet is used as a combiner of a head-up display. As adhesive means, the laminated glass panel uses either one sheet or two sheets of polyvinyl butyral resin (PVB) film. In the former case the hologram sheet is interposed between the PVB film and one of the glass plate and shielded from the PVB film by a transparent resin or glass film which prevents the plasticizer contained in the PVB film from transferring to the hologram sheet. In the latter case the hologram sheet is interposed between the two sheets of PBB film and shielded from each PVB film by a transparent resin or glass film having the aforementioned property. By virtue of the shielding of the hologram sheet from the PVB film, the diffraction wavelength of the hologram sheet does not significantly shift from the aimed wavelength.

Abstract: A hologram is directly recorded in a sensitized metal substrate. The hologram may be an amplitude hologram, or may be treated to produce a phase relief hologram which may be stamped into a plastic material for reproduction, be archivally stored, or used as a master for electroforming a second durable surface relief hologram for use as an embossing master. A suitable material is prepared from a polished silver plate exposed to halogen vapors. After exposure, the plate is developed and fixed, and the surface is differentially etched to form a surface relief suitable for hologram embossing. Daguerreotype processes are modified to make surface amplitude holograms and phase holograms. By etching through a metal film a semiconductor mask is obtained. By depositing a silver film directly on a wafer, masks are made with very high feature definition.

Abstract: A photosensitive material is provided which comprises (i) a substrate comprising a crosslinked polymer having a transmittance of 90% or more in a wavelength region of from 400 to 700 nm and a refractive index of 1.55 or more, and (ii) a sensitive material layer provided on the substrate and mainly composed of a vinylcarbazole polymer. A hologram member employing the photosensitive material is also provided.

Abstract: Wavelength response of volume holograms is altered by contact with a dry film diffusion element.

Abstract: A compact and portable diffraction grating maker comprised of a laser beam, optical and fiber optics devices coupling the beam to one or more evanescent beam splitters, and collimating lenses or mirrors directing the split beam at an appropriate photosensitive material. The collimating optics, the output ends of the fiber optic coupler and the photosensitive plate holder are all mounted on an articulated framework so that the angle of intersection of the beams can be altered at will without disturbing the spatial filter, collimation or beam quality, and assuring that the beams will always intersect at the position of the plate.

Abstract: Noise is reduced in computer generated holograms (CGH's) by a method of overexposure. The CGH is used to make a master hologram. The master hologram is then used to make a copy from which a succession of other copy holograms is made. Each successive copy hologram is exposed less than the prior ones while increasing brightness uniformity. Consequently, a decreasing amount of change in exposure is required to reach 100% efficiency. The number and orientation of the copy holograms is incorporated into the design of the final optical element. The final hologram is not overexposed, since the amount of exposure has been reduced from the earlier holograms, and can be used in complex optical power systems.

Abstract: Film speed of holographic photopolymer film containing polyvinyl acetate binder and an ethylenically unsaturated monomer is improved by including acrylic anhydride in the film.

Abstract: A hologram is fabricated by opening a volume phase reflection hologram formed in a recording medium such as a positive photoresist. The opening occurs by forming a second hologram, such as an off-axis hologram, in the same recording medium. The opened hologram can be replicated in metal and the metal can be used to emboss the fringe pattern of the opened hologram into plastic. A full range of colors in the visible spectrum may be obtained by metallizing the embossed plastic structure and then by overcoating it with appropriate clear dielectric layers.

Abstract: A method for the formation of a diffraction grating on a substrate using a holographic technique and an etching technique, wherein the periodicity of the pattern of the diffraction grating can be changed at will by a change of the light-path length of one of the two light fluxes from a holographic exposing system.

Abstract: Presence of a ring opening monomer polymerizable by free radical sigma-bond cleavage in a photopolymerizable composition improves volume reflection holograms prepared from the composition.

Abstract: Solid storage stable photopolymerizable compositions are provided that are useful in preparing optical elements, and especially holograms. The composition contains a polymeric binder, N-vinyl carbazole and a photoinitiator system that has a hydrogen donor component.

Abstract: There is described a method of processing exposed holographic material to obtain holograms having a broader band replay a hologram which is of the silver halide in gelatin binder type which method comprises holographically exposing the holographic material by use of coherent light, developing the holographic image by a chemical process and then treating the material sequentially either firstly with a solution of an anionic surfactant which comprises at least one alkyl group having at least four carbon atoms and then with a solution of a quaternary ammonium compound which comprises at least one alkyl group having from 10 to 18 carbon atoms or a polymeric compound which comprises at least one quaternary ammonium group in the repeating unit or firstly with a solution of said quaternary ammonium compound or polymeric compound and then with a solution of an anionic surfactant, the material being subjected to a silver bleaching step at one stage after development.

Abstract: Holographic color control systems are disclosed for the production of pseudocolor holograms by in-situ sequential swelling of an emulsion and exposure to three color separation images with a single wavelength reference light source. The resulting holograms yield images in three color primaries with excellent color registration and mixing, producing a full gamut of mixed colors, pastels and neutrals with three-dimensional perspective.

Abstract: A photographic contact printing process is disclosed having application in the mass production of replicate video discs from a master disc, and other applications wherein it is desired to replicate micro-detail over a relatively large area. A problem with conventional contact printing from a mask to a photographic medium is one of maintaining intimate contact over a relatively large area since dust, dirt, etc., are almost impossible to completely eliminate in any practical manner. In accordance with the present invention, a contact printing process is provided wherein intimate contact is not necessary for making high quality contact prints. The present invention recognizes that in contact printing information from a master disc to a replicate disc, the contact printing process is significantly less sensitive to imperfect contact between the master disc and the replicate disc if one employs a replicate disc comprising a photosensitive material having a certain optical properties.

Abstract: A method is disclosed for making holograms on transparent surfaces. A protective thin substrate 18 is laminated to a temporary support 24 for processing. This procedure protects the delicate thin substrate 18 through the processing steps. Upon completion of the processing steps, the thin substrate 18 is then removed from the temporary support 24. The applied photosensitive material gives the delicate thin substrate 18 added strength. The thin substrate 18 is then laminated to the final surface 26. In one embodiment, the final surface 26 corresponds to a car windshield 34. Playback lamps 36 located in the dashboard 32 illuminate the thin substrate 18 to read the holographic image.

Abstract: A method of preparing a hologram which is of the silver halide in gelatin binder type which method comprises holographically exposing the holographic material by use of coherent light, developing the holographic image by a chemical process and wherein after development the material is treated with an aqueous solution of an anionic surfactant which comprises at least one alkyl group having at least four carbon atoms, to achieve bathochromic shift in the replay wavelength.

Abstract: Volume phase holograms and other holographic elements are disclosed which include microscopic areas of a material having an index of refraction different from that of the holographic fringes.

Abstract: A hologram which comprises a light transparent base having coated thereon a hydrophilic water-swellable layer which contains the holographic image and a dye whose peak absorption is below the peak replay wavelength of the hologram. The hologram is produced by adding the dye after exposure of the hologram.

Abstract: Holographic notch filters are provided that comprise photopolymer films, having an optical density of at least 2, mounted on a transparent substrate.

Abstract: Holographic photopolymer compositions having fluorinated binders are provided that produce excellent reflection holograms when holographically imaged.

Abstract: Wavelength response of volume holograms is altered by contact with a dry film diffusion element.

Abstract: Presence of a ring opening monomer in a photopolymerizable composition improves reflection holograms prepared from the composition.

Abstract: A hologram recording assembly includes a transparent, absorbent member supported on a substrate. The transparent member is positioned to be directly incident to an exposure beam. The transparent member is out of moisture equilibrium during an exposure time. Consequently, the transparent member increases or decreases in thickness depending on a moisture difference between it and the environment. As the thickness changes, a phase shift in the light reflections within the recording assembly blurs spurious holograms while leaving the desired hologram intact.

Abstract: Optical Combiners are provided for use in Head-Up Displays. The Combiners have a refractive index modulation greater than approximately 0.001.

Abstract: Solid photopolymerizable compositions and photosensitive elements are provided that are useful in preparing optical elements, and especially holograms. The composition contains a polymeric binder, a liquid ethylenically unsaturated monomer, and a photoinitiator system. Typical compositions have a refractive index modulation of at least 0.005 when measured per the specified test.

Abstract: Improved holographic optical elements are disclosed that contain a reflection hologram. Also, an improved process for forming reflection hologram.

Abstract: A method and apparatus for forming a multiple exposure hologram includes an object beam cut out mask 24 and reference beam cut out mask 60. Different segments of the masks are left uncovered during each exposure step and operate to shape the reference 18 and object 16 beams so that they illuminate selected areas of the photosensitive plate 12. The angle of incidence of the object beam 16 remains constant during each exposure step while the reference beam 18 illuminates the plate 12 at different angles during each exposure step. During playback, a plurality of lamps 94-106 project reconstruction beams at the hologram 12 to individually or collectively render the holographic segments viewable with a minimum of crosstalk between each segment. In the preferred embodiment, the reference beam mask includes diamond-shaped cut outs 62-74 which are selectively used with associated object beam mask cut outs 28-40 to generate a hologram in the form of a seven-segment display.

Abstract: A photosensitive composition comprising:(a) a compound of the formula ##STR1## (b) an ethylenically unsaturated compound capable of free radical initiated addition polymerization;(c) a polymeric binder; and(d) a free radical generating system activatable by actinic radiation which comprises a hexaarylbiimidazole and a chain transfer agent.A single step process for forming a light-stable hologram using this photosensitive composition is also disclosed.