The synthesis of holograms by computer requires the calculation of the complex amplitude emitted by an object in the hologram plane. Several approaches exist that decompose the object into primitives like points and lines. We assume that the object to be imaged can be approximately decomposed into congruent triangles. In a preprocessing step, we calculate wavefields for the triangle whose transformed copies build the object surface. The computed wavefields represent triangles rotated by different angles and positioned in different depths. The resulting wavefields are stored as conventional color images with alpha channel in a lookup table indexed by rotation angle and distance from the hologram plane. Each pixel in the texture codes a complex number. Every triangle of the input object has a corresponding entry in the lookup table. The rotation angles and the distance of the triangle determine the selection of the appropriate texture. The textures are rendered using special graphics hardware, and interference is simulated. The lookup table helps to react immediately to transformations of the input object. Texture swapping and repositioning according to the object movings lead to full- parallax hologram generation for small objects in real-time.

This paper presents a compression algorithm applicable for transmitting a HPO hologram data. The proposed algorithm exploits a modulating function to compress the bandwidth of an object wave, resulting in data reduction due to relaxed Nyquist sampling constraints. At the receiver, the compressed data will be interpolated and compensated via being divided by the modulating function. We derive the algorithm and present compression rate. Finally, we show the validity of the proposed algorithm by simulation where a reconstructed image from undersampled data is compared with a reconstructed image obtained from proposed algorithm.

Continuing advances in both computing and modulator techniques and technologies increase the likelihood of electro-holography displays becoming practical in the next five years or so. These displays aim to allow high quality, interactive, 3D images to be generated from compte held dat. Until now, large pixel counts have precluded any systems of practical utility. This paper will describe recent progress towards meeting the challenges of implementing such displays. Despite more than exponential increases in computer performance, interactive hologram calculation remains an issue. A significant part of the cost of any electro-holography product will be associated with the computational requirements. These are strongly influenced by the choice of computer generated hologram (CGH) type, the algorithm used to calculate the CGH and the computer architecture chosen for implementation. The leading optics will be discussed and some experimental results presented indicating performance, cost and image quality tradeoffs. Eventual choice will depend on the specifications of the required system. Another traditional bottleneck has been the optical modulator employed. As one of the leading candidates for practical implementation, the current and projected performance of the DERA Active Tiling system will be explored, and the latest experimental results presented. These will include the first published, full parallax, true CGH, 3D image replays from an Active Tiling channel.

In order to enhance the reconstructed image fro kinoform, several kinoform synthesis methods based on optimization approaches have been proposed and used for 2D objects. In this paper, we propose a kinoform synthesis method based on simulated annealing for 3D object. The simulation results how that the reconstructed images can be significantly improved by use of the SA-based optimized kinoform.

Three fundamental problems have prevented holograms from popular public display: lighting, space requirement, and alignment. For a sufficiently large hologram, the light source for reconstructing the image can become both a fire hazard as well as a cause of eye injuries. In the case of reflection hologram, the viewer cannot observe the image closely because the light source would be blocked. Furthermore, the relative positions of each hologram and its light source are unique. 'Edge-lit' holograms are limited in size because the aspect ratio of each system is constant. The display method present here resolves all the above problems.

A 3D head mounted display (HMD) system is useful for constructing a virtual space. The authors have developed a 3D HMD system using the monocular stereoscopic display. This paper shows that the 3D vision system using the monocular stereoscopic display and capturing camera builds a 3D virtual space for a tele-manipulation using a captured real 3D image. In this paper, we describe the characteristics of 3D space reconstruction when camera parameters, which are the interval of parallax and the viewing angle, have been changed. In addition, we propose the 3D image transmission using a wavelength division multiplexing for constructing a tele-manipulation system.

The full color transmission type holographic screen for 3D image projection has a vertical direction viewing zone size of 6.5 cm. This size is too small for viewers to watch images with comfort. To increase the vertical size of the viewing zone, a vertical diffuser with an optimized scattering angle and a diffraction grating with vertical dispersion are recorded and used together with the screen. With attaching the diffuser or the grating to the screen, the vertical size of the viewing zone is increased up to 5 times with little degrading in image quality. Recording the grating and the screen on a single photo plate by exposing once is also possible. The screen performance is examined with a holographic screen with size of 60 by 80 cm².

Holographic reflectors have proved to be a viable solution to help to increase the luminance of current reflection mode LCD displays at a low cost. Here we present some alternative holographic reflectors being considered at Toppan Printing Co. Inc. for liquid crystal display applications. The reflectors show a peak brightness near the perpendicular viewing direction and are able to provide a white appearance in a wide viewing are a or a sharp color dazzling appearance.

Holographic Interferometry has been successfully employed to characterize the materials and behavior of diverse types of structures under stress. Specialized variations of this technology have also been applied to define dynamic structural behavior. Such applications of holographic techniques offer some of the most effective methods of structural analysis and flaw identification available. This technology is nondestructive, real-time, and definitive in allowing the identification of structural and mechanical geometry as well as describing dynamic behavior under stress. Structures and materials can be analyzed with very low amplitude stress or excitation and the resultant data can be used to adjust the accuracy of mathematically derived structural models or as criteria for complete inspection and analysis programs, as well as in developmental analysis.

Wood for musical instruments is a very valuable material. Subjective testing methods are widely established to evaluate quality of such a material. For this purpose, the evaluation of visual characteristics such as texture and color, and also physical and acoustical characteristics may be applied. To perform the measuring, data evaluation and material quality classification, the method VibroColorTest method is being developed. The equipment consists of two parts: VibroVizer and Colimet.

The vibrational and interferometric performance of optical tables employing automobile inner tubes as vibration isolating elements is investigated. A relation allowing the resonant frequency of a table to be determined during design is presented and verified. Michaelson interferometer fringe drift data is displayed which compares the interferometric performance of two arbitrarily selected inner tube tables to a typical commercial optical table. The use of a bare concrete floor as a suitable optical platform is explored resulting in fringe drift times of 2.6 hours. Table top construction and air current suppression are recognized as more important factors than vibration isolation in establishing interferometric stability at ground floor levels.

Real-time 3D display system using holographic optical elements (HOEs) is a diffractive display based on the reconstruction of parallax rays. This 3D display system consists of a holographic screen consists of HOEs and a spatial light modulator (SLM). Each voxel in 3D space is constructed by the convergence of rays from many pixels on the SLM through the holographic screen. This system can display animated volumetric images such as holography. In this paper, the real-time color 3D display system is described for practical use. This color 3D display system can display animated color volumetric images with viewing angle within 22 degrees.

Nowadays micro-displacement systems are quite common. In this work we propose a new technique to measure micro displacements using high frequency holographic gratings. In this technique the grating is place on the object carrying out the micro displacement. The small displacements are measured by counting the number of displace fringes of an amplified grating image as the micro-displacement takes place. The main advantage of the system we have designed is the accuracy of its measurements, which can easily be adjusted by changes in the grating frequency.

Liquid crystal spatial light modulators (LCSLMs) are promising devices for real-time holography. We are trying to use a twisted nematic LCSLM as a phase hologram. In previous years, only linearly polarized light has been applied to use the device as a phase-only modulator. Recently, eigenstates of the device were studied using Jones matrix calculus. The eigenvectors of the device represents elliptically polarized light, and the negative eigenvector indicates the preferable performance for phase-only modulation. In this paper, we generalize the calculus by introducing a polar coordinate system and angular parameters. This simplifies the analysis of device characteristics and makes it easier. It also enables us to discuss more precisely the intensity transmission and phase delay caused by the device. Finally, we present the optimum eigenvector for phase modulation in terms of the birefringence range of the LCSLM.

We present a theoretical analysis of color reflection holography using four recording wavelengths. The color reproduction of the hologram is discussed using the 1976 CIE chromaticity diagram. The optimum combination of the four wavelengths which minimizes the distance between the reconstructed image and the object points is calculated using nonlinear least square method. It is found that the extremely good color reproduction can be achieved by four- wavelength recording. We also analyze the color reproduction for the four practical laser wavelengths. The optimum choice of the wavelengths and the attainable color reproduction are discussed.

New layout for the access control system based on joint transform correlator (JTC) is presented. The carrier-key should consist of several tested holograms. Each of the hologram stores a part of entire image, stored in the reference hologram. Image domain JTC is used to match the images retrieved from the holograms. Being recorded and retrieved, and images provides correlation peaks with special positions, with a strict dependence on the tested and reference holograms mutual shifts. The optical signal transforming is considered by means of mathematical analysis. The experimental results corresponded with computer simulations are presented.

The viewing angle of the computer-generated hologram (CGH) can be expanded with lens-less Fourier configuration. It, however, requires a laser to illuminate the CGH for reconstruction. In the previous paper, we have proposed that making the second hologram for white-light reconstruction. The reconstructed image from the first hologram is used as the object beam of the second hologram. The second hologram can be either transmission or reflection hologram, which depends on the direction of the reference beam. In this paper, we propose a method to calculate CGH for the full- color rainbow hologram with enlarged viewing angle. First, we calculate the master hologram with three virtual slits whose positions are corresponding to red, green and blue wavelength. The transfer hologram can be made from the master CGH with single exposure. In the experimental result, we obtain full-color computer-generated rainbow hologram with 17 degrees of viewing angle and 3.0 mm by 2.5 mm image size.

The method of measuring modulated transfer function of rainbow holographic image is described. The 12 rainbow holograms of special object by using one-step technique was recorded. The rainbow holographic image was obtained from a white-light source. The comparison of obtained results with viewer sensory characteristics is presented.

A 3D head mounted display (HMD) system is useful for constructing a virtual space. The authors have developed a 3D HMD system using the monocular stereoscopic display. This paper shows that the 3D vision system using the monocular stereoscopic display and capturing camera builds a 3D virtual space for a telemanipulation using a captured real 3D image. In this paper, we propose the monocular stereoscopic 3D display and capturing camera for a tele- manipulation system. In addition, we describe the result of depth estimation using the multi-focus retinal images.

We proposed a new spatio-angularly multiplexed holographic memory system using moving windows and double-focusing lens, which can eliminate crosstalk due to two neighboring moving windows in the vertical direction of the conventional moving window holographic memory system, and demonstrated its feasibility through optical experiments.

A binary computer generated hologram (CGH) and a Fourier Transform hologram (FTH) with gray level/quasi-colors are similar to all appearance in the structure of hologram cell. However, they are wholly different in display techniques by the use of gray level or quasi-colors. It is possible to directly take a picture of reduced FTH, i.e., a kind of positive and negative transparency, displayed on a standard color LCD/CRT using a negative film with high contrast.

The paper considers the computation and fabrication of computer-generated phase holograms (CGH) that can produce specific light patterns in the near field of diffraction. It is shown that: 1) near-field elements do not have periodic phase structures and have to be recalculated each time the geometrical parameters and wavelength change; 2) short-focus elements require a lot of calculations because the step of the sampling grid used in computation should be less than the smallest feature of the phase structure. Performance simulation of multifocus CGHs is done both symmetric and asymmetric 1D/2D output intensity distributions. The fabrication technology is described. Comparison between experiment and simulation is made.

We have been developing holograms and holography technology for more than two decades for various applications. Embossed-type holograms manufactured by NDP are commercially available and are used widely in Japan. Currently, we are developing volume-type holograms. Some holographic optical elements (HOEs) and color graphic-arts are ready for commercialization. We are studying color holograms are ready for commercialization. We are studying color holograms as the next generation of volume-type holograms. At the previous SPIE meeting, we reported on the process for mass producing full-color Loppmann holograms and the adhesive film employed. This paper concerns the mastering process. It should be simple so as to be suitable for mass production, and a hologram copied from a master should have limited viewing range so as to provide greater brightness. To obtain a brighter hologram with the desired viewing angle, we employ a new modified Denishuku method for mastering. In this study, the relationship between the incident angles used for mastering and for copying was examined, and a new way of limiting the viewing area was devised. Through a combination of our mastering, replication and adhesive technologies, we have succeeded in mass production full- color holograms for the first time in the world. This has enabled DNP to develop commercial-level color graphic-arts holograms, some of which are widely available in the marketplace.

A general review of the current holographic materials available from the Geola distribution network is presented. Recommended chemistries for both pulsed and CW-laser recorded Silver Halide holograms are reviewed. Color control techniques for Silver Halide reflection holograms are discussed. Finally new recipes for developers and bleaches are presented.

Silver halide sensitized gelatin (SHSG) holograms are similar to holograms recorded in dichromated gelatin (DCG), the main recording material for holographic optical elements (HOEs). The drawback of DCG is its low energetic sensitivity and limited spectral response. Silver halide materials can be processed in such a way that the final hologram will have properties like a DCG hologram. Recently this technique has become more interesting since the introduction of new ultra- fine grain silver halide (AgHal) emulsions. In particular, high spatial frequency fringes associated with HOEs of the reflection type are difficult to convert employing SHSG processing methods. Therefore, an optimized processing techniques for reflection HOEs recorded in the new AgHal- materials is introduced. Diffraction efficiencies over 90 percent can be obtained for both transmission and reflection diffraction gratings. Understanding the importance of the selective hardening process has made it possible to obtain results similar to conventional DCG processing. The main advantage of the SHSG process is that high-sensitivity recording can be performed with laser wavelengths anywhere within the visible spectrum. This simplifies the manufacturing of high-quality, large-format HOEs, including also high-quality display holograms of the reflection type, both monochrome and full color.

Photochemical characterization and holographic recording of fulgide Aberchrome 670 and 540-doped polymethyl methacrylate (PMMA) were investigated. Upon UV and visible exposure, closed-form absorbency followed first-order kinetic. The real time holographic recording in fulgides doped PMMA films were studied. The effect of dye concentration, thickness of the film and the recording intensity on diffraction efficiency was reported. We used the Langmuir-Blodgett (LB) technique in order to transferring a compact multilayer of fulgide spread on water surface between two thin films of cellulose acetate (CA). The preliminary results of the surface pressure-area isotherms obtained by LB show the transfer of the fulgide between two CA thin films. Finally, the photochromic reaction of fulgide in LB films was investigated.

We observed that newly developed near-stoichiometric LiNbO₃ crystals doubly doped with Tb and Fe have three different types of energy levels: UV absorption centers just above the valence band, metastable shallow electron traps slightly below the conduction band, the deep traps located about 1.9 eV below the conduction band. Irradiation with UV light induced a stable absorption band extending from (lambda) equals 650 nm to the absorption edge, which is caused by the photoinduced charge transfer from UV-sensitive absorption centers to deep traps via the conduction band. The electron lifetimes at shallow and deep traps could be controlled by doping concentrations. Based on these favorable energy states, nonvolatile two-color holographic recording has been demonstrated by use of 852-nm recording beams and UV gating light. Quasi-nonvolatile one-color recording at 532 nm has also been demonstrated in these codoped crystals. Hologram recording from the UV-exposed, colored state revealed a much improved sensitivity in comparison to that from the uncolored state.

We report the synthesis of polycrystalline barium titanate BaTiO₃ thin films on silicon substrate prepared by sol- gel technique. The structure and composition of ferroelectric film ms have been analyzed by using x-ray photoelectron spectroscopy and Rutherford backscattering spectroscopy. These methods provide information on the core level electronic states and the film composition. The results indicate the films have no distinctive deviation from the stoichiometry within the accuracy of both spectroscopic methods. Thus, this study of surface structure and composition of ferroelectric films could lead to a better understanding of the observed change of electrical and optical properties and to the design of improved devices such as dynamic random access memories.

Varieties of applications require the technology that allows storing, and processing a large volume of information. Holographic technique offers high-density data storage with parallel access and high throughput. Several methods exist for data multiplexing based on the fundamental principle of volume hologram Bragg selectivity. We recently demonstrated that spatial shift selectivity associated with a random encoding of the reference beam is an alterative method for high-density, high capacity data multiplexing. In this report we show some characteristics of the random encoded reference beam hologram selectivity and discus the parameters of the recording material that should work optimal for this method.

Archival data-storage based on holographic methods requires high performance recording materials. Here, we describe an epoxy-photopolymer composite material which is sensitive to visible light and can be fabricated as thick films. These materials are prepared by combining photopolymerizable vinyl monomers with a liquid epoxy resin and an amine hardener. As the epoxy cures at room temperature, a solid matrix is formed which surrounds the unreacted photopolymer. These vinyl monomers are subsequently photopolymerized during hologram recording. Typically the material consists of a low index matrix, composed of diethylenetriamine and 1,4- butanediol diglycidyl ether, and a high index photopolymer mixture of N-vinylcarbazole and N-vinyl-2-pyrrolidinone. Because the polymers can be prepared in thick formats, narrow angular bandwidth holograms with high diffraction efficiency can be recorded. A dynamic range up to 13 has been measured in these materials.

Experimental results demonstrating the coherent scattering properties of a cationic ring-opening photopolymer are presented. The film is exposed continuously with a single beam at a single angle, and the transmission characteristics are measured as a function of exposure. A critical cumulative coherent exposure level is observed. At exposures above this level the presence of noise gratings is observed through a decrease in the transmittance of the photopolymer. The magnitude of the efficiency of these gratings differs depending upon the method used for preconditioning the photopolymer. Noise gratings are also measure in the case of angularly multiplexed exposures, and it is found that if the exposure fluence of each multiplexed recording is reduce to levels consistent with those used for recording data pages in this sensitive recording medium then no measurable noise gratings are formed.

In this communication we present the experimental results obtained when diffraction gratings are stored using pulsed exposure in polyvinyl alcohol/acrylamide photopolymer deposited in a dry film. The influence of the energy of the irradiation pulse was studied and the number of pulses needed to reach maximum diffraction efficiency was obtained. The recording was performed using a n holographic copying process. The original patten employed was a gratin of 1000 lines/mm processed according to sliver halide sensitized gelatin, with a beam ratio of 1:2 and transmittance of 75 percent. We exposed the samples by recording holograms with as collimated beam from a frequency-doubled Nd:YAG Q- switched laser. The pulse duration was approximately 8 ns and the frequency of repetition varied between 2 and 10 Hz. The pulse fluence was increased from 0.07 mJ/cm² to 6.7 mJ/cm². Our initial results show that it is possible to obtain diffraction gratings with a diffraction efficiency of 60 percent. The energetic sensitivities achieved are close to those obtained when working with the same material and continuous irradiation, without processing of the gratings.

Berreman's 4 by 4 matrix method, which calculates light propagation through a stack of anisotropic thin films, is used to calculate the reflection of electromagnetic waves from a volume hologram. This matrix method is compared with the coupled wave analysis of unslanted and slanted reflection volume holograms and good general agreement is obtained. The Berreman method allows for an arbitrary dielectric profile along the thickness of the grating. This allows gratings to be evaluated with square, sinusoidal, or irregular morphologies. The model is applied to the specific case of chirped photopolymer gratings. The Berreman method also allows for uniaxial layers, which permits the investigation of birefringence. Measurements show essentially no birefringence in DuPont photopolymer holograms.

Our experience of work with the photopolymer with diffusive amplification (PDA) as an extremely thick holographic recording medium evidences many attractive properties of this material, especially for such particular applications, as very selective holographic optical elements. However, sometimes the experimentally obtained characteristics of recorded holograms differ from the expected ones. This may be caused by the insufficient knowledge on the material behavior at different regimes and its specific peculiarities. In the present paper we analyze some parameters of PDA, in particular the noise source, and kinetics of the refractive index modulation and diffraction efficiency, as compared with the dynamic photopolymer medium Reoxan. As well as discus the possibilities of application of the PDA material.

The old Lippmann color photography technique has been investigated. Today, high-resolution panchromatic recording materials are on the market suitable for Lippmann photography. The holographic panchromatic silver-halide materials from Slavich in Russia, as well as the panchromatic photopolymers from DuPont in the USA can be used for recording Lippmann photographs. In particular, the Slavich emulsion has been investigated for recoding Lippmann photographs. In order to understand the Lippmann technique better, computer simulations of the recording and reconstruction process have been undertaken. A Lippmann color photograph is unique and almost impossible to copy, which makes it suitable for the document security application. A new optical variable device (OVD) technique is under development. This type of photograph can be applied to personal documents as a new optical security device, e.g., passports, ID cards, etc., can carry a Lippmann OVD. The recording of a Lippmann photograph requires a special panchromatic recording material, e.g., silver halide materials or photopolymer materials.

In the last several years, holographic elements have been introduced into a wide array of display applications. Holographic Reflectors are incorporated with liquid crystal displays to shift optimum viewing angle away form specular glare and raise brightness by concentrating light at a convenient viewing angle. Reflectors can be produced in blue, green, gold, red, or white colors. Denso GlassVision projection screens incorporate transmission holograms to efficiently direct projected light to the viewer in a screen that reverts to clear glass When the projection image is turned off. JVC has introduce da large-screen HDTV that uses a holographic color filter to separate blue, green, and red light from the illumination beam, and direct the sorted colors to the appropriate color pixel, raising brightness with a passive component. Most recently, HOE prototypes have been produced to improve the efficiency of portable liquid crystal color display. Front diffuser are affixed to the face of reflective color LCDs and direct output light from the LCD to the viewer at a convenient viewing angle in a concentrated view cone. Reflective Colors Filters are pixelated diffuse reflectors internal to the LCD structure and aligned to the LCD matrix. These reflective filters provide higher brightness, larger color gamut, and better color saturation including a holographic grating are under development to provide wider view angle in direct-view LCDs.

Two wave-mixing (TWM) is reported for an acrylamide based photopolymer at a wavelength of 633 nm where the material absorbs light. Measurements of diffraction efficiency where also made at 441. In TWM experiment, transfer of energy from the reference beam to the object beam is showed and the mechanism of the image formation is studied using real time measurements.

We present the results of the study as holographic recording material of aphotopolymerizable mixture of polyvinyl alcohol and acrylamide, with a photo initiator system formed by a 1:1 molar mixture of the anionic dye Rose Bengal (RB) and the cationic one Methylene Blue (MB), with triethanolamine as coinitiator. Under irradiation with 514 or 633 nm light and comparative conditions, photopolymers with this photo initiator system give rise to a clear sensitivity enhancement, with regard to the use of any of the dyes alone. Still higher enhancements were achieved using as absorbing component an isolated ion-pair from the 1:1 mixture of both dues, with some different properties than those of the physical 1:1 mixture of dyes. Maximum diffraction efficiencies of 35-64 percent with 30-100 mJ.cm^-2, and spatial resolution of ca. 1000 lines.mm^-1, could be reached. The photo initiator mechanism using either the mixture RB/MB or the isolated ion-pair RB-MB is likely based on charge-transfer processes from the excited chromophores, that seems to be favored in the case of the ion-pair.

We report a new photochromic composite polymer consisting of poly-N-epoxypropylcarbazole (PEPC) polymeric matrix with a nitro-brome-substituted spiropyran (BNSP) photochromic dye. The PEPC + BNSP films can be considered as negative photochromic recording media. They are colored in the initial state and bleached upon irradiation within the visible spectra. When we placed the bleached samples to the darkness, they slowly revert to the colored form. This process has strong temperature dependence, so one can either 'freeze'' or accelerate changing of the current coloration state in the PEPC + BNSP. The experimental measurements are evaluated in conjunction with its potential applications for optical holographic recording in the visible spectral range. The real-time holographic recording procedure in PEPC + BNSP films was studied. The diffraction efficiency values reached the maximum of 23 percent at spatial frequency of 1600 line pairs per mm, during direct hologram recording with the 532 nm Coherent VERDI laser irradiation. Light exposures were ranged from 70 to 280 mJ/cm². The investigated compounds have good perspectives for use in holography, two-photon optical data storage, electro-optics, and optical-limiting applications due to coupling of some unique properties such as high optical non-linearity, well charge transport, short response times, no-limiting resolution ability, etc.

Silver halide photographic plates and photo-polymers have been utilized for the holographic recording. These materials are available only for recording of still pictures, and require complex developing process and relatively long time for recording and reproduction of the image. As an alterative, image recording using bismuth sillenite compound has been researched. The BGO and BSO single crystal bulk samples have been sued for these studies. On such background, we aimed to fabricate BGO and BSO films for image recording. Thin films have merits in device integration and mass production. We have already found out the process condition to obtain good crystalline BGO films on glass substrates. The film with crystalline phase only was obtained at the substrate temperatures above 200 degrees C. In this paper, BGO and BSO films were deposited on glass substrates and the ITO conducting films on the glass substrates using RF magnetron sputtering method. Preliminary image recording experiments were carried out for a BSO single crystal and its film. Image recording properties were characterized for the polycrystalline films with different film thickness by recording interference fringes using the Ar ion laser.

We present a description of the characteristics of a solution, which is photosensitive, composed of a resin and phenol red with isopropyl alcohol as the solvent. We have used this solution to record a diffraction grating with the aid of an Argon Ion laser thus obtaining phase gratings with a diffraction efficiency of the order of 1 percent with a resolution of 381 lines/mm. The main advantages of this solution are shown to be its low cost and ease of use.

Toppan Printing Co., Ltd. originated the name of 'grating image'. It means an image that consists of diffraction grating dots that look similar to the halftone dots of conventional printing. We proposed this new display method using simple gratings in order to enhance the visual effects when illumination is made by a fluorescent lamp. We considered the use of simple gratings as elemental dots, and used a number of elemental dots to display a 2D image. This method produces an effect something like the halftone dots of printing. The grating image technology grows from its starting to become able to produce 3D images and a 3D-video system using an electron beam grating-writing system.