Abstract: A hologram is formed using a grating and a second hologram serving as an image hologram. The grating is constituted by a plurality of areas whose spatial frequencies and diffraction directions are different from each other. This grating is formed using a grating array and a mask. The second hologram has a plurality of areas each of which records information or image (e.g., ID data) serving as a recording target as an element hologram. The second hologram is formed using a Fresnel hologram serving as a first hologram. The first hologram can also be formed using a mask and a diffuser on which ID data is projected. On the hologram, information (pattern or image) is recorded with each of reference light components having different directions corresponding to the different small areas. Even if illumination light having a uniform wavefront is irradiated on this hologram, it is difficult to detect all the information (pattern and image).

Abstract: A hologram with a dynamically controlled diffraction efficiency and enhanced signal-to-noise ratio is recorded in ferroelectric photorefractive materials, such as strontium barium niobate (Sr.sub.x Ba.sub.1-x Nb.sub.2 O.sub.6) (SBN), BSTN, SCNN, PBN, BSKNN, BaTiO.sub.3, LiNbO.sub.3, KNbO.sub.3, KTN, PLZT and the tungsten bronze family. The diffraction efficiency of the hologram is dynamically controlled by applying an electric field along the polar axis of the ferroelectric photorefractive recording medium. Electrically controlled diffraction is used in conjunction with hologram fixing and operation of the material at a temperature in the vicinity of or above its Curie temperature to additionally provide prolonged, low-noise readout. The general methods for recording and reconstructing a hologram (or a set of multiplexed holograms) using these techniques is disclosed.

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: A method and system for fabricating a multiple holographic element. The method comprises the steps of forming a master multiple holographic element having an absorption grating pattern that produces a given index of refraction pattern across the master multiple holographic element, coating the master holographic element with a layer of a photopolymer, and directing a recording beam to and through the master holographic element and into the photopolymer layer. The absorption grating pattern of the master holographic element modulates the amplitude of the recording beam, and the modulated recording beam causes the monomers of the photopolymer to form a monomer pattern that produces the given index of refraction pattern across the photopolymer layer. The method further comprises the steps of fixing the monomers of the photopolymer layer in that monomer pattern to form thereby a copy of the multiple holographic element, and removing the photopolymer layer from the master holographic element.

Abstract: A beam homogenizer for converting an incident beam of non-uniform spatial power or energy distribution into an output beam of uniform spatial power or energy distribution. The homogenizer is a holographic optical element constructed from an array of facets or subholograms and positioned at a first plane in the path of an incident signal. The transmittance from each subhologram is uniformly spread across a target at a second plane that is spaced away from the first plane Another optical element, such as a holographic collimation element, may be placed at the second plane to collimate the transmittances thereupon.

Abstract: 055745798Heads-up and heads-down displays employing holographic stereograms are provided. The stereograms can be oriented perpendicular to the user's line of sight (the "90.degree. case") or at angle to the line of sight (the "non-90.degree. case"). The stereograms are produced using a three-step process in which a series of two-dimensional perspective views are prepared, a H.sub.1 hologram is prepared from the two-dimensional perspective views, and a H.sub.2 hologram is prepared from the H.sub.1 hologram. For the non-90.degree. case, the two-dimensional perspective views are oriented at an angle relative to the plane of the H.sub.1 hologram during the preparation of that hologram. Similarly, during the preparation of the H.sub.2 hologram for this case, the H.sub.2 hologram is oriented at an angle relative to the H.sub.1 hologram. In this way, the viewing slits generated by the holographic stereogram are located in the vicinity of the user's eyes for the non-90.degree. case as is desired.

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: A method and system for fabricating a multiple holographic element. The method comprises the steps of forming a master multiple holographic element having an absorption grating pattern that produces a given index of refraction pattern across the master multiple holographic element, coating the master holographic element with a layer of a photopolymer, and directing a recording beam to and through the master holographic element and into the photopolymer layer. The absorption grating pattern of the master holographic element modulates the amplitude of the recording beam, and the modulated recording beam causes the monomers of the photopolymer to form a monomer pattern that produces the given index of refraction pattern across the photopolymer layer. The method further comprises the steps of fixing the monomers of the photopolymer layer in that monomer pattern to form thereby a copy of the multiple holographic element, and removing the photopolymer layer from the master holographic element.

Abstract: Holographic images are constructed in a recording material in accordance with a temporal interleaving technique in which a first set of images is constructed for a predetermined first imaging time with a predetermined first time gap being defined between each of the images. Thereafter, in accordance with a subsequent predetermined sequence a subsequent set of images is constructed into the same predetermined location. The image sets have at least one member in common. In one aspect all of the images are constructed into the same predetermined defined region of the holographic recording material (an angle hologram). In another aspect the predetermined defined region into which each of the images is constructed is separate from all other regions of the holographic recording material (a spatial hologram).

Abstract: A multiple-color filter array (94) useful as part of a flat panel display system of either a projection (50) or direct view (70) type is constructed using reflection holography techniques. The filter array includes multiple-color filter elements (110, 114, 116) that reflect wavelengths of light corresponding to colors outside of a color band of interest. Redundant sets of first, second, and third wavelengths selective reflective color filter elements are arranged in stripes to transmit light of the three primary colors red, green, and blue. The three-color filter array is constructed in a single layer (122) of holographic recording material during one sequence of three separate exposures, one for each color filter element. A preferred flat panel display system (200) includes a liquid crystal variable optical retarder of the supertwisted nematic (STN) type.

Abstract: A method of photoelectrically reading information recorded in the form of a Fresnel hologram, which makes it possible to eliminate the effect on the reading accuracy of a scratch, a stain, etc., on the hologram surface when the recorded information is reconstructed by applying a light beam having a small diameter to the hologram. The surface of the hologram is illuminated by scanning it with a light beam having a cross-section smaller than the hologram recording region, thereby reconstructing and reading the same recorded information separately from different hologram regions, and thus compensating for momentary disability to reconstruct the recorded information due to a scratch or stain. At the same time, since a light beam having a small beam diameter is used for reconstruction, the depth of focus of the reconstructed image increases, so that the number of restrictions on the installation position of the read sensor decreases.

Abstract: A novelty filter utilizes self-nulling and self-aligning of reflection and transmission phase conjugate beams. A photorefractive crystal is arranged so that the contributions to the phase conjugate are equal and opposite in the steady state to produce destructive interference when the input image is stationary, and thus no output image is displayed. If the image moves, then the gratings will rewrite and erase themselves, each with their own response times, total destructive interference will not occur, and transient enhancement and surpression of the phase conjugate output signal will indicate the direction of motion of the input image.

Abstract: An inexpensive electronic display that presents 3D images by binocular parallax is disclosed. The effect produced is that of a real-time holographic stereogram. The pixels of a 2D display are spatially multiplexed by two HOEs to produce a plurality of lateral viewing zones of 2D rasters, similar to the method used in lenticular screen systems. A directional screen HOE scatters incident light over a lateral viewing zone so small that typically only one eye of a viewer can occupy it at a time. A multiplexer HOE comprised of thousands of tiny holograms, each when reconstructed projects a spot onto the directional screen HOE. The sum of all these spots forms a two-dimensional raster of spots on the directional screen HOE. Each spot can be projected onto the directional screen HOE from at least two laterally different angles and thus reconstruct the directional screen HOE from at least two laterally offset angles, consequently creating at least two laterally offset viewing zones of each spot.

Abstract: A hologram structure including a hologram layer including a half-tone pattern of transparent areas and reflection hologram areas, and a non-hologram half-tone pattern of areas that are substantially opaque to the range of wavelengths that comprises the spectral bandwidth of the holograms areas located adjacent the hologram layer, wherein the hologram areas are superimposed with selected areas of the non-hologram half-tone pattern.

Abstract: A hologram manufacturing apparatus and a hologram manufacturing method for manufacturing a hologram optical device by a split exposure method are disclosed. The manufacturing apparatus comprises light shield means having a spatial light modulator having a light transparent area and a light non-transparent area thereof controlled corresponding to an input signal, and drive means for driving the spatial light modulator by supplying the signal to the spatial light modulator. The light shield means is arranged closely to a photosensitive material.

Abstract: A hologram structure for use in a holographic center high mounted stoplight system for a vehicle. The hologram structure includes an illumination source for providing a reconstruction beam, a first array of non-overlapping hologram cells and non-hologram cells, and a second array of non-overlapping hologram and non-hologram cells. Each hologram cell of the first array produces a specular image that is viewable in a first predetermined angular field pursuant to diffraction of a portion of the reconstruction beam, and each hologram cell of the second array produces a diffuse image that is viewable in a second predetermined angular field pursuant to diffraction of a portion of the reconstruction beam. The specular images and diffuse images produced by the first and second holograms form stoplight illumination.

Abstract: A high efficiency, broad bandwidth, volume holographic element for diffraction windows. This holographic element is fabricated so that it can passively track and diffract solar radiation throughout the course of a day. Such a hologram can effectively illuminate the interior of a building or room with sunlight. This invention can reduce both lighting costs and the cooling costs associated with generating artificial light.

Abstract: A security device includes first and second diffractive structures contained within a surface relief structure. The structures are such that the device responds to illumination at a first, visible wavelength to generate a first, visible pattern while any pattern generated by the second structure is not substantially visible at that wavelength, and the device responds to illumination at a second wavelength substantially different from the first wavelength to generate a second pattern suitable for machine reading while any pattern generated by the first structure is substantially suppressed relative to the machine readable pattern at that wavelength.

Abstract: A holographic storage media for storing digital data in the form of an interference grating is provided which includes a substrate (48) over which a perforated opaque structure (50) is disposed. The opaque structure (50) has wells (52) disposed therein. In the wells, a photopolymer material (54) is disposed to form data storage regions (54). This is covered by a capping layer (56). The wells (52) are chemically and/or optically isolated from each other.

Abstract: A hologram structure for use in a holographic center high mounted stoplight system for a vehicle. The hologram structure includes first and second hologram layers laminarly secured to each other, each having a plurality of bright hologram cells and dim hologram cells formed therein, and each hologram cell being configured to diffract light into a predetermined solid angular region. The bright hologram cells and the dim hologram cells of each hologram are arranged in a pattern to produce a recognizable pattern of bright and dim areas.

Abstract: Multiple volume holograms are recorded by changing the incidence angle of the reference beam at one wavelength. The stored holograms are reconstructed at another wavelength by using the reference beam oriented at the proper incidence angle. The proper holographic data are retrieved by pre-formatting or post-formatting the holographic data to be recorded or reconstructed. This usage of using different wavelengths for recording and reconstruction are independent of the scanning mechanisms for the reference beam. Utilization of holographic memories for storage and retrieval of data, and correlations can make use of this invention.

Abstract: A hologram surface to express a phase distribution, a visual field in which a solid image can be seen; and a stereoscopic display limit are set in a virtual space. A target to be stereoscopically displayed is subsequently expressed in the virtual space by a set of micro polygons. A plurality of slice planes which are parallel with the horizontal plane are set into the virtual space including the target. The line segments which intersect the polygons are obtained for every slice plane. The detected line segment is divided or clipped as necessary and is finally divided into the portion which can be always seen from the whole region of the visual field and a portion which is obstructed by another line segment and can be seen from only a part of the visual field, thereby extracting the line segment.

Abstract: A hologram structure for use in a holographic center high mounted stoplight system for a vehicle. The hologram structure includes a hologram layer having a plurality of holographic lenses formed therein, each holographic lens being configured to diffract light into a predetermined solid angular region.

Abstract: A waveguide holographic telltale display for displaying images to a vehicle driver via the vehicle windshield. A light source injects light into the base of a clear inner windshield singlet. A mirror hologram between the inner and outer singlets confines a majority of the injected light to the inner singlet. An image hologram between the windshield singlets diffracts light out to the vehicle driver. A halfwave plate between the image hologram and the inner singlet reduces ghosting and allows the driver to view the images even through polarized sunglasses. IR light is blocked by a tinted outer singlet or a holographic solar coating. The display does not suffer from ambient turn from the sun, and the light source is hidden away from the vehicle dash.

Abstract: A holographic display and method for displaying hologram are disclosed. The method and apparatus provides a compact display arrangement in which the light source for illuminating the display is integral with the display, or in other words, an external light source is not necessary. The hologram utilized in the display is formed as a rainbow hologram, with a converging reference beam utilized in forming the diffraction grating upon the holographic plate. The display includes a pair of spaced transparent glass sheets, with the light source disposed between the glass sheets. The holographic plate formed with the converging reference beam is then mounted upon one of the glass sheets, with the light source illuminating the holographic plate with diverging illumination light. A mirror is associated with each of the transparent glass sheets at a location adjacent to the light source, with the reflective surfaces of the mirrors facing each other.

Abstract: An information display system has a display screen which is substantially transparent to a selected band of wavelengths of light and can be mounted on a window. A projector projects an image of light of the wavelengths to which the display screen responds onto the screen to reflect or transmit the selected wavelengths of light from the screen. The screen is formed as a holographic optical element which reflects the light such that an observer is able to see the projected image from the display screen only if his eyes are within a predetermined area, while observers outside of the area see only a substantially transparent display screen on the window.

Abstract: A hologram structure for use in a holographic center high mounted stoplight system for a vehicle. The hologram structure includes a hologram layer having a plurality of single grating holograms formed in therein, each single grating hologram configured to diffract light at a respective predetermined angle.

Abstract: A color matrix display including a color matrix reflective filter (10) having groups of reflective red, green and blue (R, G, B) color elements (12) arranged in subgroups (20). The elements (12) of each color group (R, B, G) in each subgroup (20) are aligned with pixel subgroups of a matrix control element or LCD (18). The color elements (12) of the reflective filter transmit light (26) of their associated color to an aligned pixel associated with that color and reflect back (30) light of other colors to a reflective light assembly (16) for reuse. The color matrix reflective filter (10) is made by selectively exposing selected areas of a holographic optical element, or HOE, with a light of colors other than the color desired to be transmitted by that element (12) of that selected area.

Abstract: By modifying the exposure sequence of the facets in a hologon during manufacture, it is intended to maximize the spatial frequency of the error especially in hologons having large numbers of facets so that the error frequency is multiplied by a large factor, thereby greatly reducing the eye's ability to detect banding problems. This method also minimizes the adjacent facet error as far as is practical.

Abstract: By modifying the exposure sequence of the facets during manufacture of a hologon image writer the visibility of cross scan errors are minimized, thereby reducing exposure error and visible banding. With hologons having a number of facets "n" the general form of the exposure sequence is 1, n, 2, n-1, 3, n-2 . . . .

Abstract: A moving holographic image is projected into three space by producing a series of slides or fixed holographic images in quick succession in a process similar to a conventional motion picture All of the slides are produced on a single photochromic surface in succession by writing on the surface with UV light. Each slide consists of a set of identical strip holograms positioned on the photochromic surface as an array. Each strip hologram is produced by creating a series of traces arranged side by side. As the maxima traverse the surface, the UV source is turned on and off according to a program to produce a series of dots of either unchanged or darkened color on the photochromic surface. During the next scan a new set of unchanged or darkened dots are produced on each strip hologram, and so on until the slide is completed. After being illuminated the surface is quickly washed clean in preparation for the next slide by illuminating it with a burst of high intensity UV light.

Abstract: A reflection hologram structure including a transparent substrate, and a pattern of shielded hologram containing regions and transparent regions disposed on the transparent substrate, the pattern being unresolvable to the viewer. The shielded hologram containing areas comprise hologram subregions and shielding subregions overlying the hologram subregions. The shielding subregions comprise for example, opaque regions or partially illumination transmissive regions.

Abstract: A lamp arrangement for a motor vehicle comprises a light source including a plurality of bulbs and arranged in a rear shelf panel, and a transmission hologram mounted on a rear window on the cabin side thereof. The transmission hologram includes a plurality of divisions which have different diffraction characteristics from each other. Almost all incident lights from the light source are diffracted by any of the divisions rearward of the vehicle.

Abstract: A method is disclosed for making holographic images by recording an array of pixels which together form a two or three dimensional composite image. Each pixel corresponds to a sampling of just those rays which would pass through a given point on the surface of an ordinary hologram. Every common type of hologram can be made by this method, including 2D/3D holograms, stereograms, and full color holograms. Each pixel is a white light viewable hologram generated by recording a small hologram near the narrowest part of a converging bundle of rays of coherent light, usually with each ray corresponding to one point on the object, and the rays in a pixel being confined to a horizontal plane intersecting the surface of the object.

Abstract: An optical system for reading a plurality of radially contiguous individual holograms previously recorded on a rotatable disk along at least one of the disk tracks, each hologram being representative of a predetermined data pattern, and each being recorded as a Fourier transform hologram with respect tot the direction (y direction) tangential to the tracks and as a Fresnel hologram with respect to the radial direction (x direction), and wherein the optical system illuminates the disk with a read-out beam which is at least partially reflected by the disk to an array of photosensitive detectors which generates electrical data signals. A latch circuit is included for recovering the value of each data signal when the read-out beam completely illuminates one of the holograms.

Abstract: An inexpensive wallpaper, which may be plastic and self adhesive. Using the positive features and advantages of thin-layer holograms and other existing technology, the claimed invention produces a changing, moving or stable 3-D effect in the presence of a low-powered laser illuminating system. In usual (incoherent) light, the claimed wallpaper reflects light as does a standard wallpaper. On the claimed wallpaper, images of any kind can be additionally printed without damaging the coherent 3-D reconstruction. The claimed wallpaper produces 3-D images, whose qualities are not affected by mechanical damage of any kind, including scratching or scraping, and it can also be produced in a washable embodiment. The suggested object incorporates recognized computer techniques, by which an image of any level of complexity can be included. The wallpaper can be printed on plastic or other media by sequentially applying a pre-prepared small-area matrix.