Abstract: The present invention relates to an optical switch comprising a paraelectric photorefractive material, storing a hologram, possibly a latent hologram, whose reconstruction, or activation and reconstruction, is controllable by means of an applied electric field. The hologram may be formed by spatial modulation of the refractive index of the paraelectric photorefractive material, which arises from the quadratic electro-optic effect induced by the combined action of a spatially modulated space charge within the paraelectric photorefractive material and an external applied electric field. The present invention further relates to a switching network, such as a multistage network, for use in an optical communications system, incorporating at least one optical switch according to the invention.

Abstract: A color hologram recording medium 2 includes volume hologram recording mediums 14R, 14G and 14B for diffracting light of wavelengths different from each other. Reconstruction patterns 1R, 1G and 1B of the volume hologram recording mediums 14R, 14G and 14B are recorded so that the reconstruction patterns 1R, 1G and 1B are reconstructed at reconstruction positions different from each other. Thus, the color hologram recording medium 2 can have a wide variety of designs and artistic characters that the recorded color reconstruction patterns vary depending on watched directions.

Abstract: A mechanical device for tilting an optical element consisting of one or more actuators attached to a support element supporting an optical filter or other optical device is provided. In one preferred embodiment of the present invention, a rigid support element is free to move at one end, or is attached by a hinge at one end to an actuator while movement of its second end is restrained, resulting in tilting of the support element when the actuator is activated. In another embodiment of the present invention, a deformable support element is rigidly attached to the actuator at one end while movement of the second end of the support element is restrained, resulting in bending of the support element and tilting of the optical element upon movement of the actuator. In yet another embodiment, a deformable support element is rigidly attached to two actuators, resulting in bending of the support element when the actuators are activated.

Abstract: A system for use with a releasable screen is described. The system may be used in a method of influencing purchasing decisions.

Abstract: This invention pertains to the design of optimized far field viewing devices that simultaneously produce bright far field holographic light patterns and achieve good see-through performance to present a well focused scene. A far field transmission hologram recorded on a transparent substrate has regions having high diffraction efficiency juxtaposed with regions having low diffraction efficiency. The high diffraction efficiency regions contribute to production of bright far field holographic light patterns, whereas the low diffraction efficiency regions contribute to see-through performance.

Abstract: There is described an image-recording medium and an image-reading method, which make it possible to improve reading accuracy of information by avoiding duplication of an optical variable image with the information. The image-recording medium includes a substrate, an image-receiving layer provided on the substrate and an optical variable layer provided on the substrate, wherein at least a part of the optical variable layer includes an optical variable image, and the optical variable image is formed in a manner such that the optical variable image, overlapping with an image recorded on the image-receiving layer, emerges in a first direction, while the optical variable image, overlapping with an image recorded on the image-receiving layer, does not emerge in a second direction.

Abstract: A method of fabricating a hologram screen having a large visual range and a hologram imaging apparatus used for the particular method of fabricating the hologram screen are disclosed. A plurality of mirrors (3) extended toward a plurality of photosensitive members (5) are arranged at a plurality of end portions (21), respectively, of a light diffuser (2). At least a reference beam (41) and object beams (42) passed through the light diffuser (2) are radiated on a plurality of the photosensitive members (5) individually thereby to form a plurality of holograms. These holograms are integrated with each other by being arranged two-dimensionally thereby to fabricate a hologram screen. Among the mirrors (3), a reference beam-side mirror (31) arranged nearer to the light source of the reference beams (41) is extended from the light diffuser (2) by a length varied with the position of the photosensitive member (5) to be exposed.

Abstract: A method of advertising on a motor vehicle having a substantially transparent window including steps of providing a holographic film with a holographic image, and adhering the holographic film to the window, where the holographic image is substantially transparent to an operator of the motor vehicle from within the motor vehicle so that operation of the motor vehicle is not impeded, but the holographic image is visible to an observer outside the motor vehicle. The present method may also include the steps of applying a transparent adhesive to the holographic film and/or the window. The holographic image may be a product name, a corporate name and/or a corporate logo. The motor vehicle may be a motorsport vehicle adapted to be raced in a race track with at least one other vehicle. The holographic image may be a numeral that distinguishes the motorsport vehicle but is preferably a sponsor advertisement that includes a product name, a corporate name and/or a corporate logo.

Abstract: A beam homogenizer that minimizes undesired intensity variations at the output plane caused by sharp breaks between facets in previous embodiments. The homogenizer includes a hologram made up of irregularly patterned diffractive fringes. An input beam illuminates at least part of the hologram. The hologram transmits a portion of the input beam onto an output plane. In doing so, the energy of the input beam is spatially redistributed at the output plane into a homogenized output beam having a preselected spatial energy distribution at the output plane. Thus, the illuminated portion of the output plane has a shape predetermined by the designer of the homogenizer.

Abstract: A dot matrix hologram with a hidden image is disclosed, wherein the hidden image technology is applied to a dot matrix hologram. Although the hidden image technology has been used in a conventional hologram, it has not been used in a dot matrix hologram. Although the above two kinds of hologram both can show hidden images with illuminating laser light, the disclosed dot matrix hologram with a hidden image and the conventional hologram with a hidden image use different working principles and have different detailed characteristics to create hidden image regions.

Abstract: Apparatus for producing dot matrix holograms through laser ablation utilizing only two two-axis, low-inertia beam deflectors to control the maximum holographic direction, and the holographic coloration of the individual pixels of the holograms, and the method of utilizing that apparatus.

Abstract: A holographic security device comprising first and second holographic generating structures (2,3) recorded in respective sets of substantially non-overlapping regions of a record medium is disclosed. The regions of one set are interleaved with regions of the other set, whereby both interleaved line structures are substantially non-visible to the unaided eye, whereby the holographic security device generates two or more holographic images (A,B) viewed from separate viewing directions around the device and normally seen by tilting the device. Each particular holographic image in a viewing direction is generated in whole or part by the holographic structure associated with one set of interleaved lines.

Abstract: The invention makes it possible to form a hologram for reproducing a three-dimensional image easily free of limitations placed by the size of the three-dimensional image to be reproduced, the size of the hologram and reference light for reproduction. A controller calculates a three-dimensional interference pattern for generating reproduction light associated with a desired three-dimensional image when a recording medium (1) is illuminated with reference light for reproduction, divides the three-dimensional interference pattern into partial interference patterns and calculates reference light and information light for recording for each of the partial interference patterns. A final hologram is formed by illuminating the recording medium (1) with reference light and information light for recording using a head (10) while changing the relative positional relationship between the recording medium (1) and the head (10) by moving the head (10) with a VCM (13) while transporting the recording medium (1).

Abstract: A method of advertising on a motor vehicle having a substantially transparent window including steps of providing a holographic film with a holographic image, and adhering the holographic film to the window, where the holographic image is substantially transparent to an operator of the motor vehicle from within the motor vehicle so that operation of the motor vehicle is not impeded, but the holographic image is visible to an observer outside the motor vehicle. The present method may also include the steps of applying a transparent adhesive to the holographic film and/or the window. The holographic image may be a product name, a corporate name and/or a corporate logo. The motor vehicle may be a motorsport vehicle adapted to be raced in a race track with at least one other vehicle. The holographic image may be a numeral that distinguishes the motorsport vehicle but is preferably a sponsor advertisement that includes a product name, a corporate name and/or a corporate logo.

Abstract: There is disclosed an optical device in which a first light source for outputting a first wavelength light is apart from a second light source for outputting a second wavelength light by a predetermined distance. An information recording medium is irradiated with the first and second wavelength lights transmitted through a holographic optical element having first and second diffraction areas. The first and second diffraction areas are provided with grating arrangements in which grating axis directions are parallel to each other and grating pitches are different from each other. The first and second wavelength lights reflected by the information recording medium are transmitted through the holographic optical element and diffracted by the first and second diffraction areas.

Abstract: The hologram recording sheet according to the invention is made up of a base film and hologram sensitive materials sensitive to different wavelength regions formed therein in a desired pattern, or a film and at least two hologram recording sensitive materials sensitive to different wavelength regions laminated on the film with a transparent plastic spacer layer located therebetween, thereby enabling the required diffraction light wavelengths to be recorded on the required sites without producing unnecessary interference fringes. At least two hologram recording sensitive materials sensitive to different wavelength regions are formed on different sites on a film in dotted or striped configuration, the size of which is up to 200 mm or at least twice as large as the thickness of the sensitive material layers, thereby enabling regions diffracting light of different wavelengths to be formed in the form of independent sets of interference fringes.

Abstract: The invention provides a computer-generated hologram which can be viewed in white at the desired viewing region and a reflective liquid crystal display using the same as a reflector. The computer-generated hologram H is designed to diffuse light having a given reference wavelength &lgr;STD and incident thereon at a given angle of incidence &thgr; in a specific angle range. In a range of wavelengths &lgr;MIN to &lgr;MAX including the reference wavelength &lgr;STD wherein zero-order transmission light or zero-order reflection light of incident light on the computer-generated hologram at a given angle of incidence is seen in white by additive color mixing, the maximum diffraction angle &bgr;2MIN of incident light of the minimum wavelength &lgr;MIN in the wavelength range and incident at the angle of incidence &thgr; is larger than the minimum diffraction angle &bgr;1MAX of incident light of the maximum wavelength &lgr;MAX in the wavelength range and incident at said angle of incidence &thgr;.

Abstract: A hologram of an increased size using a single color laser, capable of executing a full color regeneration in a desired view angle and a method for producing the hologram. A plurality of photo-sensitive members are independently exposed to obtain respective holograms, which are connected by using an adhesive layer 80 constructing a connecting means, in order to obtain an integrated hologram expanded in two-dimensional direction. The holograms are obtained by an interference of a reference light 22 and an object light passed through a light diffusing body 24 in order to cause the light diffusing body 24 to be recorded on the photo-sensitive member. The size of the light diffusing body 24 is such that the spectral characteristic of the diffused light from the hologram can attain a desired efficiency at least over the entire wavelength range of the visible light.

Abstract: A thickness of each hologram lens for forming a hologram color filter is set so as to be smaller as the wavelength of light to be diffracted by each hologram lens is shorter. A thin plate glass layer is bonded to a surface of the hologram color filter such that it is in a firm contact therewith by adhesive agent and a sum of the thickness of the thin plate glass layer and thickness of the adhesive agent is smaller than the shortest focal length of the focal lengths in glass of a plurality of the hologram lenses. As a result, light diffracted and divided by the hologram color filter is focused on a picture element electrode of a corresponding color properly thereby eliminating deterioration of color reproduction due to mixing of colors. Further, upon production of the hologram color filter from hologram recording material, an influence of a fringe rotation is compensated.

Abstract: The invention provides a hologram plate which is used with the double-focus replication process, and which is integrated with a spacer to impart marring resistance thereto, and is integrated with a light absorbing layer to allow zero-order light and first-order light to have substantially the same intensity. This hologram plate 42 comprises an array of collective element holograms for diffracting parallel light incident thereon at a specific wavelength and a specific incident angle in such a way that the light is converged onto a specific focal length position. The hologram plate 42 is a multilayer structure made up of a first transparent substrate 31, a hologram layer 32, an adhesive layer 33 and a second transparent substrate 41. The second transparent substrate 42 defines a surface in contact with a hologram photosensitive material 53 during hologram replication.

Abstract: A description is provided of an optical information recording and reproducing apparatus employing a holographic memory. The apparatus includes a mask disposed in an optical path of the signal light beam so as to cover a light intensity distribution of the signal light beam incident into the holographic memory at nearly a half portion thereof with respect to the center of the distribution of the zeroth-order diffracted light of the signal light beam. The center of a region of the holographic memory where the signal light beam and the reference light beam intersect with each other, is shifted by a distance substantially equal to twice the distance between peaks of the zeroth-order diffracted light or the first-order diffracted light of the signal light beam.

Abstract: Holographic memory including a plurality of HOEs stacked in a vertical direction for two dimensional addressing of a recording medium for increasing a recording capacity and improving productivity and cost.

Abstract: A simplified method is provided for recording identification information, such as a serial number or the like, in a hologram-recorded film simultaneously with hologram duplication. The method includes the steps of coupling a hologram recording film with a master hologram plate having a master hologram, the master hologram plate having a reflective area adjacent the master hologram; and directing laser beams towards the master hologram plate to induce interference between incident laser light and diffraction laser light from the master hologram in the recording film, at least some of the laser beams radiating the reflective area through a transmission type controllable display device to record a pattern in the hologram recording film corresponding to a pattern displayed at the transmission type controllable display device.

Abstract: A color display apparatus includes a light source for emitting white light, a spectral unit for dispersing the white light into a red (R) light ray, a green (G) light ray, and a blue (B) light ray, and a spatial light modulation device. The spatial light modulation device includes a single hologram lens layer for diffracting and emitting incident light rays in predetermined directions depending on incident angles and wavelength bands and a liquid-crystal panel having a liquid-crystal layer for performing light modulation according to video signals of corresponding colors to light rays admitted through the hologram lens layer to emit the light rays, and color light components of an R light ray, a G light ray, and a B light ray admitted on the spatial light modulation device through the spectral unit are admitted on the hologram lens layer at different incident angles of the respective color light rays.

Abstract: A projection liquid crystal display apparatus has a light source for emitting white light and a liquid crystal display unit, between which a holographic optical element serving as the color separating/focusing means is disposed. Upon receipt of the white light, the holographic optical element performs separation into light components of the primary colors of red, green and blue, at angles corresponding to the arrangement of the pixels on the liquid crystal display unit so as to direct these primary color light components to pixels of the corresponding colors, an whereby image to be reproduced (real image) is formed on the liquid crystal display unit. The holographic optical element is produced by using the liquid crystal display unit as an exposure mask.

Abstract: A phase watermark hologram “W” is composed of a blaze having binary phase difference of 2&pgr;×n, where “n” is a natural number of more than 1. An watermark appears in response to phase difference, which changes by a faked blaze. A phase watermark hologram “W” and a phase hologram “D” indicating data are formed on a same surface of a substrate mixed in arbitrary locations and arbitrary ratio of both holograms.

Abstract: An image recording method and apparatus for recording an image on a holographic stereogram in such a manner as to generate an optimum reproduced image, and an image reproducing method and apparatus capable of generating an optimum reproduced image from the holographic stereogram. A parallax image string is recorded as a series of strip- or dot-shaped hologram elements by having an object light beam and a reference light beam fall on one and the other surfaces of a recording medium for hologram 130. On the reference light incident side, a light inlet block 52 is arranged for having contact with the recording medium for hologram 130 so that no significant change in the refractive index will be produced on an interface with the recording medium for hologram 130. The reference light beam is illuminated via this light inlet block 52 on the recording medium for hologram.

Abstract: A technique for mapping working images to adjacently and continuously tiled subapertures having CGHs on a plate is disclosed with the result that the entirety of a working area of a plate is completely covered with working subapertures, these subapertures usually being rectangular. The design technique thereafter determines a phase function which approximately maps desired regions on each subaperture from portions of the working image in the workpiece plane. Steps in the process include first a determination of the size and shape of subapertures representing each feature. Second, a determination of the geometric transformation for each feature is made. Thereafter, backpropagation or other refinement to create the desired intensity profile at the workpiece is made.

Abstract: Holographic memory including a beam source for emitting a beam, a beam splitter for splitting the beam into a reference beam and an object beam, a hologram memory unit for recording information designated to a cell when the reference beam and the object beam are incident thereto at a time, and reproducing the information recorded before when only the reference beam is incident thereto, a first optical path changing unit for directing the reference beam to be incident to the hologram memory unit at an arbitrary angle for recording and reproduction of the information, including a first deflector for deflecting the reference beam to an arbitrary angle, a second deflector for re-deflecting the reference beam deflected at the first deflector in a vertical direction, and a telescope having at least one composite HOE(Holographic Optical Element) for directing the reference beam re-deflected at the second deflector to be incident to the hologram memory unit, and a second optical path changing unit for adjusting an op

Abstract: The hologram recording sheet according to the invention is made up of a base film and hologram sensitive materials sensitive to different wavelength regions formed therein in a desired pattern, or a film and at least two hologram recording sensitive materials sensitive to different wavelength regions laminated on the film with a transparent plastic spacer layer located therebetween, thereby enabling the required diffraction light wavelengths to be recorded on the required sites without producing unnecessary interference fringes. At least two hologram recording sensitive materials sensitive to different wavelength regions are formed on different sites on a film in dotted or striped configuration, the size of which is up to 200 mm or at least twice as large as the thickness of the sensitive material layers, thereby enabling regions diffracting light of different wavelengths to be formed in the form of independent sets of interference fringes.

Abstract: A decorative construction 10 for attachment to a vertical surface wherein the decorative construction 10 includes a main image unit 11 comprising a generally elongated rectangular sheet of decorative paper 20 and a plurality of holographic image units 12 adapted to be operatively associated with the front face 23 of the sheet of decorative paper 20.

Abstract: A reflective liquid crystal display contains, a holographic reflector that provides either a white or more neutral background color to the display when viewed with ambient white light. The holographic reflector comprises a holographic recording film layer that includes at least first and second pixel volumes containing holographic mirrors and, preferably, third pixel volumes containing holographic mirrors.

Abstract: A method for dynamically refreshing a holographic data storage medium wherein data is stored in a plurality of data pages, each of which comprises a two dimensional pattern of pixel data. Each data page is stored by interfacing an image or a Fourier transform of the data page with a reference beam to form a holographic recording of the data page in the holographic medium. Pursuant to the method, all of the data pages are classified as either good pages, each of which was written into storage less than a threshold time ago related to the decay of the holographic recording, or empty pages available for writing, or self-erasing pages which are self-erasing with time. At sequential time intervals, the oldest good page is read which then becomes a self-erasing page, and its data is rewritten into an empty page which then becomes the youngest good page, and the oldest self-erasing page becomes an empty page.

Abstract: An apparatus for producing a dot matrix hologram is provided, which can fabricate a hologram of high quality, simplify the construction, and reduce the cost.

Abstract: To produce a rainbow-type holographic stereogram, an object beam is focused in the vertical direction with a cylindrical Fresnel lens. On the other hand, according to the edge-lit scheme, a reference beam is applied to a hologram recording medium via a light introduction block. A color holographic stereogram can be produced by utilizing a phenomenon that the color of a reproduction image is varied by moving the cylindrical Fresnel lens by a proper distance in the vertical direction.

Abstract: A method and a system to re-align onto a detector array a holographic image of a Fourier region hologram stored in a medium, with the medium spinning around a first axis, and the hologram being generated by a reference beam and a signal beam. In generating the hologram, the reference beam is incident on the medium with respect to a second axis at a second-axis-incident angle, and a third axis at a third-axis-incident angle, such that the holographic image of the hologram when reproduced by the reference beam is aligned onto the detector array. Also, the three axes are substantially orthogonal to each other. As the medium spins, the medium's orientation can change through tilting with respect to the second and the third axes so that the holographic image when reproduced by the reference beam is not aligned onto the detector array.

Abstract: A composite hologram comprises a plurality of hologram tiles arranged for display, each of said hologram tiles formed by exposing each of a plurality of different unexposed photographic plates simultaneously to light scattered by an intermediate hologram using a conjugate complex of a first reference wave from a coherent light source and to a second reference wave from said coherent light source.

Abstract: Fast speed hologram memory device, including a first holographic optical element array for directing a reference beam to a desired hologram memory cell directly and a second holographic optical element array for directing an objective beam to a desired hologram memory cell directly, both having a plurality of holographic optical elements one to one matched to a plurality of the hologram memory cells.

Abstract: A polarisation independent optical switch is constituted by a light input (6), a diffractive and re-configurable liquid crystal device (8), a collimating lens (7) for distributing the input light over the liquid crystal device (8), a transform lens (9) receiving light from the liquid crystal device (8) and light output (6), wherein no polarisers are present between the light input and output. The diffractive and re-configurable liquid crystal device (8) may be formed as a liquid crystal spatial light modulator configured as a binary phase computer generated hologram with the holograms required to form broadcast, individual or multicast switching being re-generated using an iterative algorithm and then being recalled on demand. In one embodiment the switch has a folded configuration and includes a reflector (10) so that the light input and output are both on the same side of the liquid crystal device (8).

Abstract: Disclosed are a hologram unit of an optical pickup which has a main hologram and auxiliary alignment holograms around the main hologram thereof and a method of attaching a hologram plate of the optical pickup comprising the steps of: illuminating an object with an LD; forming an LD radiant point on a monitor through a microscopic lens, and a plurality of radiant points around the LD radiant point by auxiliary alignment holograms; and aligning the LD with the hologram plate by moving the hologram plate so as to form the LD radiant point in the center of the plurality of radiant points.

Abstract: A chirped pulse amplification system employs chirped quasi-phase-matched (QPM) gratings as dispersive delay lines for stretching and/or compressing ultrashort pulses. QPM gratings with periods varying along the beam propagation direction produce simultaneous second-harmonic generation and, in general, both amplitude and phase modulation of this second harmonic output. The aperiodic QPM gratings are designed to provide stretching or compression of the output second harmonic pulse with respect to the fundamental-wavelength input pulse. The chirped QPM gratings are also used for simultaneous harmonic generation and compressing of the chirped output from a femtosecond laser oscillator. In general, the aperiodic QPM gratings can be used to efficiently produce arbitrarily shaped second-harmonic pulses.

Abstract: The invention is directed to an information-recorded medium with easily selectable and identifiable items of information, which is virtually protected against forgery and has enhanced security against some improper use, and a method for reading such a medium. This information-recorded medium 1 includes a substrate 2 and a layer 3 with information recorded thereon by the printing of infrared absorbing ink, said layer 3 being provided on the surface of the layer 2. The printed layer 3 is provided thereon with a relief hologram-recorded layer 7 through an adhesive layer 4, said hologram-recorded layer 7 being built up of a reflecting layer 5 transparent to the infrared region and a relief hologram-formed layer 6 provided on the surface of the reflecting layer 5. For reading, the hologram-recorded layer 7 is reconstructed by visible light, while the printed layer is reconstructed by infrared light, and the medium 1 is identified on the basis of the thus reconstructed information.

Abstract: A hologram of a virtual object or an object which actually exists is formed and a solid image is displayed. 3-dimensional information of the object to be displayed is divided into regions in the depth direction. Depth images are formed as 2-dimensional images where are seen from a plurality of points which are obtained by finely dividing the hologram forming surface for every region. A phase distribution at the hologram forming surface is calculated from the depth images and displayed on a liquid crystal display or the like as an electronic hologram. A reference light is irradiated onto the display and is converted into an optical wave front, thereby displaying a solid image. When forming a hologram recording medium, a zone image corresponding to each of the finely divided exposure regions of a dry plate is exposed multiple times.

Abstract: Systems and methods for steering a complex, spatially-modulated incident beam of light from a spatial light modulator to gain access to data locations in a holographic memory cell (HMC). One of the systems includes (1) a primary beam steering system that receives the incident beam of light from the spatial light modulator and produces a resulting beam of light, wherein the primary beam steering system traverses the resulting beam of light across a plane of the HMC in increments having a first magnitude and 2) a fine-control translation mechanism, coupled to the spatial light modulator, that translates the spatial light modulator relative to the primary beam steering system to cause the resulting beam of light to traverse the plane of the HMC in increments having a second magnitude smaller than the first magnitude.

Abstract: A holographic display including a planar transparent light pipe (11) configured for rotation about a light pipe rotation axis that is orthogonal to the planar extent of the transparent light pipe and passes through a rotational center of the light, a multiple image hologram structure (13) having a plurality of holographic images attached to one side of the planar transparent light pipe, wherein the images are at different azimuthal angular positions on the light pipe about the light pipe rotation center, and a light source (17) for illuminating an input surface of the transparent light pipe such that an injected beam propagates within the light pipe to provide reconstruction illumination for a portion of the multiple image hologram structure.

Abstract: A heads-up display unit provided with a display device serving as display image forming means which displays a display image. A hologram serves as a reflecting means, and reflects the display light emitted from the display device, causing reflection of the display image on the interior surface of a vehicle's windshield. A display image is formed outside the windshield towards the front of the vehicle. A concave mirror having a different focal length in different directions is recorded in the hologram serving as a reflecting means so as to offset distortion of the display image caused by curvatures of the windshield. This construction makes it possible to cause the windshield to display a display image free from distortion.

Abstract: In a method and apparatus for displaying a stereoscopic image, a plurality of 2-dimensional images having parallaxes in only horizontal directions are obtained and inputted when an object to be displayed is seen from different positions in the horizontal direction. The 2-dimensional image is divided in the vertical direction into 1-dimensional line images which are elongated in the horizontal direction. A phase distribution of a corresponding hologram segment is calculated from the pixels of the line image. The calculated phase distribution is displayed on a hologram forming surface of a phase displaying section using a display. A reproduction light is irradiated and converted into an optical wave front and is further enlarged in the vertical direction, thereby displaying a solid image. The 2-dimensional images are inputted by photographing the object by a plurality of cameras arranged in the horizontal direction.

Abstract: A product, method, and apparatus are provided for making a stereoscopic hologram from a series of two-dimensional views of an object. The two-dimensional views are obtained from, for example, computer analysis of scans taken by standard medical diagnostic equipment. The views are reproduced on an LCD screen, and the screen then serves as the modulator of the holographic object beam. An exposure of each view is sequentially made on a different section of a holographic recording medium, which may be, for example, a photopolymer placed on a substrate. As the observer views the finished product, each eye looks at a different section of the hologram, thus providing a stereoscopic effect.

Abstract: A composite hologram incorporates a plurality of hologram tiles arranged for display, each of the hologram tiles formed by exposing each of a plurality of different unexposed photographic plates simultaneously to light scattered by an intermediate hologram using a conjugate complex of a first reference wave from a coherent light source and to a second reference wave from the coherent light source.

Abstract: A microlithographic tag comprising an array of individual computer generated holographic patches having feature sizes between 250 and 75 nanometers. The tag is a composite hologram made up of the individual holographic patches and contains identifying information when read out with a laser of the proper wavelength and at the proper angles of probing and reading. The patches are fabricated in a steep angle Littrow readout geometry to maximize returns in the -1 diffracted order. The tags are useful as anti-counterfeiting markers because of the extreme difficulty in reproducing them.