Abstract: A method for patterning a layer on a substrate can include projecting coherent radiation toward a reflector surface so that the coherent radiation is reflected off the reflector surface to provide a holographic projection of a desired image wherein the reflector surface includes information that corresponds to an inverse of the holographic projection of the desired image. The substrate including the layer can be maintained in the path of the reflected radiation so that the holographic projection is projected onto the layer. Related systems are also discussed.

Abstract: The invention provides a hologram-recording subject plate comprising a block and a variety of subjects fixedly contained therein, which ensures easy, stable yet continuous recording of a multiplicity of identical holograms or different holograms reconstructible by illuminating light as is the case with a hologram-replicating method, a hologram-making method using the same, and a hologram-recorded article. The subject plate comprises a transparent solid block 5 and a hologram-recording subject S contained therein. A photosensitive material film 1 is applied directly onto one surface of the subject plate, and the subject plate is then irradiated with laser light 7 through the photosensitive material film 1. Such simple operation enables a multiplicity of identical holograms to be recorded in an easy, stable yet continuous manner.

Abstract: Transmission and reflection type holograms may be formed utilizing a novel polymer-dispersed liquid crystal (PDLC) material and its unique switching characteristics to form optical elements. Applications for these switchable holograms include communications switches and switchable transmission, and reflection red, green, and blue lenses. The PDLC material of the present invention offers all of the features of holographic photopolymers with the added advantage that the hologram can be switched on and off with the application of an electric field. The material is a mixture of a polymerizable monomer and liquid crystal, along with other ingredients, including a photoinitiator dye. Upon irradiation, the liquid crystal separates as a distinct phase of nanometer-size droplets aligned in periodic channels forming the hologram. The material is called a holographic polymer-dispersed liquid crystal (H-PDLC).

Abstract: An optical data storage system and method comprising a photopolymer medium having generally a polymerizable monomer, an active binder, a first, hologram recording polymerization initiator, and a second, data writing polymerization initiator. The monomer is preferably a cationic ring-opening monomer. The hologram recording polymerization initiator preferably comprises a sensitizer and photoacid generator which initiate a first polymerization in the medium which defines a format hologram. The format hologram recording is carried out via interference of a signal and reference beam, with the sensitizer being specific for the wavelength(s) of the signal and reference beams. The hologram recording polymerization is only partial and does not consume all of the monomer present in the photopolymer medium.

Abstract: The stamp (10) for a lithographic process, such as patterning a surface layer, of the invention has a stamp body (5) with at least a first recess (11) formed therein, which recess defines a first aperture (15) in the printing face (3) of the stamp (10). The first recess (11) narrows with increasing distance to the printing face, while any cross-section of the first recess, when perpendicularly projected on the printing face (3), will lie within the aperture (15). The printing face may comprise small (11, 12) and large apertures (13) as well as small surfaces (14) in between apertures, while it is nevertheless able to produce prints which are accurate replicas of the printing face. Even details on a submicron scale can be adequately printed. The stamp (10) can be manufactured by a method which comprises anisotropic etching of a first body to make a mold and replicating the mold in the printing face (3) of the stamp (10).

Abstract: A transfer foil for use in a safety document includes a multilayer structure having a carrier layer and a plastic layer in which diffraction structures, for example holographic structures, are embossed in the form of a relief structure and which is combined with a reflective layer. The plastic layer includes a reaction lacquer layer selected from the group consisting of cationical curing lacquers, blue light-curing lacquers and chemical curing multicomponent lacquers.

Abstract: A duplicating photosensitive material film is brought into close contact with an ND glass reduced in thickness so as to become flexible or a flexible sheet or an ND glass coated with a cushioning layer through an optical contacting liquid containing a surface active agent. In addition, a spacer is interposed between a hologram original plate and a duplicating photosensitive material, and a space defined by the spacer is filled with an optical contacting liquid, thereby regulating the thickness of the optical contacting liquid layer with the spacer. Therefore, when pressure is applied, the optical contacting liquid is uniformly pressed, so that it can be made uniform and thin in thickness. Accordingly, it is possible to prevent a failure of duplication of a hologram image due to undesirable flow of the optical contacting liquid.

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 positive unit magnification reflective head is used to back-reflect a primary light beam, for storing reflection microholograms at the coincident foci of the primary and reflected beams. Imaging the primary beam focus onto itself at positive unit magnification allows increasing system tolerance to tilts and transverse misalignments between the primary and reflective heads. Holograms are stored at multiple depths in a holographic storage medium. Tunable-focus primary and reflective heads are positioned on opposite sides of the storage medium. The reflective head images each storage location onto itself at positive unit magnification. Suitable reflective heads include: two lenses in an f-2f-f configuration and a planar mirror; a lens and a corner cube; a thin lens and a thick lens with a coated reflective back surface; and a thin lens and a back-coated gradient-index (GRIN) lens.

Abstract: Provided is an optical element comprising a biopolymer having an oriented structure and a photoresponsive compound, such as a photochromic compound, wherein at least a portion of the photoresponsive compound is incorporated within the oriented structure of the biopolymer and wherein the oriented structure is laminar with the planes of the laminar orientation being aligned perpendicular to a surface of the optical element. Preferably, the biopolymer is a liquid crystal polypeptide, such as ferroelectric liquid crystal poly(&ggr;-methyl-L-glutamate), and the photochromic compound is bacteriorhodopsin. Such optical elements may be utilized in a holographic grating, in an optical correlator system such as for pattern recognition, in a dynamic holographic recording system, and in an optical switch.

Abstract: Method for the preparation of holographic diffusers where the holographic diffuser is designed through iterative calculations according to the Fraunhofer theory of diffraction and some constrain conditions. In the iterative calculation some constrain conditions that can change the magnitude of the light passing through the diffuser are used to design the diffuser. A novel iterative calculation is disclosed such that uniformed mixing of colors and high light utilization efficiency of the diffuser may be provided.

Abstract: Methods and adhesive labels useful in marking products or documents by applying these to substrates. A mark such as a barcode, photograph or characters are formed directly on the substrate and the adhesive label is applied over it. The adhesive label includes a concealing film layer which is transparent to a first wavelength outside the visible region, a diffractive optical mark with a transparent reflective layer and an adhesive layer. The first wavelength may be infrared allowing the underlying mark to be read by an IR laser. The adhesive labels are formed as to allow them to be continuously separated from a temporary detachment layer, thereby exposing the adhesive layer, and affixed to the document.

Abstract: The present invention relates to an improved process for photorefractive index grating formation utilizing polymeric photorefractive materials. The process involves the steps of: (i) exposing a polymeric optical article to electromagnetic radiation having an intensity of at least 0.05 W/cm2 for a short period of time to achieve an absorbed energy/unit volume of at least 1×103 J/cm3 to activate the article, and (ii) exposing the polymeric optical article to an electric field and electromagnetic radiation to form an index grating.

Abstract: Compositions of bacteriorhodopsin variants with increased memory time and their use for reversible optical information recording are disclosed. The compositions are characterized in that the configuration of the retinal of the photoproduct is different from the configuration of the retinal of the initial state and other than 13-cis; the pH value of the composition lies between 3 and 11; the water content of the composition lies between 1 and 30% by weight with respect to the total weight of the composition; and additives for modulating the proton mobility are present in a concentration between 1 and 80% by weight of the mass of purple membrane composition used, and if required matrix materials in a concentration of up to 10% by weight with respect to the total weight of the composition are present. These compositions may be used in reversible information recording systems.

Abstract: An improved photorecording medium suitable for use in holographic storage systems contains a glassy hybrid inorganic-organic, three dimensional matrix, in which is distributed a photoimageable system comprising one or more photoactive, organic monomers. The medium is fabricated by providing a precursor of the hybrid inorganic-organic matrix, mixing the matrix precursor with the photoimageable system, and curing the matrix precursor to form the matrix in situ. The matrix and photoimageable system exhibit independent chemistries, such that the step of matrix formation does not substantially affect the photoimageable system. The hybrid matrix precursor is typically an oligomer derived from a compound represented by RnM(OR′)4−n, where M is a metallic element having a valence of three or higher, such as silicon, titanium, germanium, zirconium, vanadium, or aluminum, R is an alkyl or aryl, R′ is a lower alkyl, and n ranges from 1 to 2.

Abstract: A print with a hologram, such as an ID card, including a transferred image including a transferred sublimable dye image of a full color using sublimable dye inks, and a hologram and the like laminated on the transferred image for security purposes. Even when stored or used for a long period of time, the hologram causes no unfavorable phenomena, such as bleeding, in the sublimation dye thermal transferred image and has excellent durability. A process for producing such a print with a hologram is also disclosed. In the production of the print with a hologram, a transferred image 2 of a sublimable dye ink or a combination of a transferred image 2 of a sublimable dye ink with a transferred image 3 of a hot-melt ink is provided on an image-receiving sheet 1.

Abstract: A method for fabricating a capacitor electrode on a semiconductor substrate includes the steps of: forming a conducting layer over the semiconductor substrate; forming a photoresist layer over the conducting layer; pattering the photoresist layer through an interfering exposure step; and pattering the conducting layer using the patterned photoresist layer as a mask, thereby forming a capacitor electrode.

Abstract: A method for marking articles or documents by placing on a substrate (1) a multi-layer optical complex consisting of an identifying portion (2, 7) such as bar codes, a photograph or characters, and an authenticating portion consisting of a diffracting optical mark, said portions being arranged one on top of the other in such a way that they cannot be separated without destroying the authenticating portion. A protected document is also disclosed which comprises an indivisible stack consisting of a printed portion (2, 7) forming an identifier read by reflection in a first wavelength band, and coated with a lacquer (5) that is opaque in the visible spectrum and has a transmission window including said first wavelength band, as well as a transparent reflective layer (4) forming a diffracting optical mark. A marking system for carrying out the method, and a device for checking said article or document, are also disclosed.

Abstract: An apparatus for making a high quality reflection type holographic optical element (HOE) using a single input laser beam, including a reflective mirror, a holographic photoplate having a photo emulsion layer on a surface nearest the reflective mirror, a cassette for retaining the reflective mirror and the holographic photoplate, and a refractive index matching fluid containing a light absorbent dye for absorbing an input laser beam. The cassette is immersed in the fluid so that fluid is retained between the photo emulsion layer of the holographic photoplate and a reflective surface of the reflective mirror. Parasitic interference patterns are suppressed by heating the refractive index matching fluid with the input laser beam, which causes a shift of the phase of the parasitic beams with respect to the phase of the beams responsible for recording the HOE. If the photo emulsion layer of the holographic photoplate consists of a dichromated gelatin (DCG), then a photo sensitizer agent (e.g.

Abstract: The invention relates to use of a material containing a polymerizable monomer or oligomer, the material exhibiting desirable shrinkage compensation upon polymerization. The material contains an expansion agent having a cleaving moiety with the capacity to be cleaved or fragmented by a catalytic reaction, e.g., acid catalysis. The cleavage, by increasing the number of molecules in the material, causes expansion that compensates, at least in part, for shrinkage induced by polymerization of the monomer or oligomer. The expansion agent is capable of providing compensation such that no more than 0.4%, advantageously no more than 0.2%, volume shrinkage per molar concentration of polymerized monomer functional groups occurs, where such compensation is performed at relatively low temperatures of less than 40° C.

Abstract: A photorefractive composite comprises a charge transport matrix and an electrooptic dye having an aliphatic group of four or more carbon atoms.

Abstract: A method for producing a tamper evident security holographic label and overlaminate using UV casting techniques, and a security device so produced, comprising a clear protective layer; a thin layer of clear UV cured resin cast partly onto the protective layer following a designed pattern; another layer of UV cured resin bearing a cast holographic image, wherein the bond of the holographic image layer is stronger toward the surface of the protective layer than it is toward the surface of the pattern layer; a reflective layer strongly attached to the adjacent holographic layer; and an adhesive layer bonded to the reflective layer. Such a composite product when adhered to a base substrate via the adhesive layer will show no visible security feature to the unaided eye due to the thin nature of the clear security pattern.

Abstract: A substrate, such as the surface of goods or of packaging material for goods, is provided with a security device by applying, to the substrate, a pressure sensitive adhesive tape carrying a security device in the form of a hologram.

Abstract: High molecular liquid crystal obtained by photopolymerizing a liquid crystal composition which comprises CH2═CHCOO—X—OC6H4—C6H4CN (X is an alkylene group) and CH2═CHCOOC6H4—C6H4CN. An optical element which is a polarized hologram element made by using the high molecular liquid crystal and an optical head having the polarized hologram element as a beam splitter.

Abstract: The present invention comprises an optically diffracting sensing device whose diffraction pattern changes upon exposure to some stimuli. The diffraction pattern may be two or three dimensional, and in one embodiment the change in diffraction patterns is recognizable to the untrained eye. The device comprises one or more gels coated onto patterned, self-assembling monolayers of alkanethiolates, carboxylic acids, hydroxamic acids, and phosphonic acids printed onto a variety of substrates, including glass, silicon, aluminum oxide, and thermoplastic films metallized with gold, or with an alloy such as nickel/gold. The present invention also comprises the method of making this device, and the use of this device.

Abstract: A paper substrate is laminated with a metalized layer forming a mirrored surface. A partially transparent black diffraction grating is applied by stochastic screening to the mirrored surface. The diffraction grating forms a random pattern from selected geometric shapes. Information, such as alphanumeric indicia or graphics, is printed on the stochastic screen to thus form a reflective diffraction device which is printable in a conventional manner while inhibiting reproduction of the printed information by conventional techniques, including black and white and color photo-reproduction and facsimile machines. The partially transparent black stochastic screen forms a diffraction grating on the metalized layer so that when illuminated from the light source of either a specular or diffuse illumination-type photocopier, random interference patterns of light occur at the interface of the metalized surface and the stochastic screen.

Abstract: A thick holographic recording medium suitable for use in multiplex holography is prepared from a solution of a bi-functional oligomer and a mono-functional monomer. Precuring, possibly at the same radiation wavelength used for recording, cross-links the oligomer, thereby creating a host for the recording monomer.

Abstract: A storage medium has at least one diffraction grating. The diffraction grating is formed as a holographic interference fringe pattern. The pattern is formed as it two-dimensionally diffracts an incident light beam in a plurality of directions or one-dimensionally diffracts an incident light beam in a direction. A combination of such patterns and also a plurality of rows of such patterns on the storage medium are available. A light beam is radiated to the storage medium. The light beam diffracted in the direction(s) is detected by a photodetector, such as a CCD device, that generates a signal carrying data stored as the holographic interference fringe pattern. The signal is then decoded by a processor to reproduce the data.

Abstract: A holographic medium uses a photosensitive polymer medium. The shelf life of the photosensitive polymer medium is improved by hermetically sealing the polymer between glass plates. The hermetic seal is designed so that high T.sub.g materials, or solder, can be used as the sealant without damage to the polymer already contained between the plates. The hermetic seal comprises metal foils attached to the plates with the edges thereof extending away from the plates in tab-like fashion. The foils are attached prior to filling the assembly with polymer. After filling, the outer edges of the foil tabs are the sealed with local heating away from the site of the polymer, or crimped using mechanical crimping.

Abstract: A non-volatile holographic recording method and system based on a doubly-doped photorefractive material. One embodiment of the holographic material is doped to have first and second types of dopants that are operable to produce charge carriers to a common band in response to radiation of a specified wavelengths. Charge carriers in the common band can migrate to a different spatial location. The dopants are also capable of recombining with charge carriers in the common band. The first type of dopants have a first dopant energy level below the band by a first energy gap greater than a second energy gap of a second dopant energy level of the second type of dopants below the common band. The first and second dopant energy levels are separated from each other so that their absorption bands to the common band are substantially separated. In addition, the first and second energy gaps should be much greater than the thermal energy k.sub.

Abstract: A volume hologram is created by exposing a volume holographic optical storage medium comprising a doped optically transparent glass matrix having a scattering coefficient of less than 10.sup.-5 cm.sup.-1 to an interference pattern created by intersecting a spatially modulated object beam with a reference beam, the object beam and the reference beam each having a wavelength of less than about 300 nm. The glass matrix may be doped with any of the following: (1) nanocrystalline semiconductor particles and an activator, (2) an alkaline earth sulfide, Sm ions, and an additional dopant selected from the group consisting of Eu ions and Ce ions, (3) ZnS and an additional dopant selected from the group consisting of Pb ions, Cu ions, and Mn ions and (4) Cu or Ce ions.

Abstract: Bacteriorhodopsin materials and matrices are crosslinked with each other to enhance optical data storage lifetimes.

Abstract: An apparatus and process for generating precision ink jet nozzle arrays in substrates is disclosed. The apparatus includes laser output through an alignment path, power monitor, expansion telescope and scanner. Preferably, beam division optics are used in conjunction with the scanner to divide out a plurality of beams and scan simultaneously a corresponding plurality of computer generated holograms (CGHs). These computer generated holograms are configured and scanned so that the generated image--preferably in the first order of diffraction--produces at least a row of ink jet holes having precision dimension and alignment preferably without optical interference from other diffraction orders. Utilizing the disclosed process and apparatus, a one step system is disclosed for going from a substrate to a finished nozzle array suitable for use with ink jet printers.

Abstract: The invention provides a hologram-recording subject plate comprising a block and a variety of subjects fixedly contained therein, which ensures easy, stable yet continuous recording of a multiplicity of identical holograms or different holograms reconstructible by illuminating light as is the case with a hologram-replicating method, a hologram-making method using the same, and a hologram-recorded article. The subject plate comprises a transparent solid block 5 and a hologram-recording subject S contained therein. A photosensitive material film 1 is applied directly onto one surface of the subject plate, and the subject plate is then irradiated with laser light 7 through the photosensitive material film 1. Such simple operation enables a multiplicity of identical holograms to be recorded in an easy, stable yet continuous manner.

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 method of making a holographic device comprising sensitizing a plurality of layers and stacking the layers to form a composite structure. Each layer is sensitized to at least one color wavelength. The method further includes directing at least two laser beams at the composite structure. Each of the laser beams is oriented at an angle with respect to an incident surface of the composite structure such that the laser beams intersect one another within one of the layers of the composite structure. The laser beams are moved along the layer to create interference patterns in the sensitized layer.

Abstract: The photorecording medium of the invention is formed by mixing a matrix precursor and a photoactive monomer, and curing the mixture to form the matrix in situ. The reaction by which the matrix precursor is polymerized during the cure is independent from the reaction by which the photoactive monomer is polymerized during writing of data. In addition, the matrix polymer and the polymer resulting from polymerization of the photoactive monomer are compatible with each other. Use of a matrix precursor and photoactive monomer that polymerize by independent reactions substantially prevents cross-reaction between the photoactive monomer and the matrix precursor during the cure and inhibition of subsequent monomer polymerization. Use of a matrix precursor and photoactive monomer that result in compatible polymers substantially avoids phase separation. And in situ formation allows fabrication of media with desirable thicknesses.

Abstract: The invention relates to a method for replicating a volume hologram having an image of a scattering object recorded therein according to a hologram replicating technique, wherein the diffraction 13 of unnecessary light due to zero-order light, etc. arising from regular reflection and a visual range capable of viewing a recorded image is limited to a desired range .alpha., so that the image can be displayed more brightly than would be possible with the original hologram plate, and a volume hologram as well. When replicating a volume hologram 4' having an image O' of a scattering body recorded therein, replicating illumination light is incident on the volume hologram 4' at an angle of incidence I.sub.1 at which a group of fringes can be replicated and recorded, said group of fringes being such that, in the vicinity of an apex defined by a supposed slant angle S.sub.g at which a replicated hologram 4' can be viewed at a supposed viewing center angle .phi. within a range .alpha.

Abstract: A tamper-evident label includes two parts that are separated from each other when an article to which they are attached is opened. The two parts have matching surface relief patterns secured to each other at an interface, and the indexes of refraction of the parts are substantially equal such that the patterns have no optical effect when attached to each other. When the two parts are separated, however, the patterns generate an image drawing attention to their separation. The patterns are preferably holographic.

Abstract: The present invention is directed to a holographic media that is composed of a mixture of a photosensitive substance such as a photopolymer and a porous rigid material such as an aerogel that provides a substructure to the composite material. This unique composition of matter can be utilized in a multitude of applications where a thick optically patterned wavefront modulating media is required, including as a holographic storage device. The composite material avoids the difficulties regarding shrinkage found in plain photopolymers. The rigid highly porous component is specially treated to receive the photosensitive material. This unshrinkable substructure has a plurality of very small, rigid pores that is essentially transparent at optical wavelengths and provides the matrix for the photopolymers. It provides holographic recording in both thin and thick formats without shrinkage and pattern distortion. The method of producing the composite holographic media is also disclosed.

Abstract: A hologram has a hologram element 3 containing a photopolymer and a cover film 22 and cover plate 21 which cover its surfaces. An adhesive 1 is used for bonding the cover film to the hologram element and the cover plate to the hologram element. The hologram has excellent humidity resistance, chemical resistance, solvent resistance and heat resistance, prevents coloration, can maintain its holographic properties and allows easy repositioning of the hologram element.

Abstract: This invention relates to film which is lettered with a laser beam comprising at least one protective film which is transparent to the laser beam, at least one opaque layer which is ablated by the laser beam, and at least one contrast-forming layer on its bottom. The abatable layer is preferably a metallic layer and can have a color like the contrast-forming layer. The color of the metallic layer is different from the color of the contrast-forming layer. The contrast-forming layer is either applied, imprinted or varnished onto the metallic layer. The contrast-forming layer can be at least one plastic film. On a side of the contrast-forming layer facing away from the metallic layer there is an adhesive layer which is covered with a carrier material, for example, an adhesive-repellant carrier film.

Abstract: A method of producing an optical element including a photopolymer layer between two holograms is disclosed. The holograms have the same diffraction spacing and refractive index, but the first hologram has an efficiency of about one-half that of the second hologram, preferably about fifty per cent and ninety-five per cent respectively. The photopolymer is polymerized to adjust the refractive index of the photopolymer until output beams will overlap and cancel each other.

Abstract: A photosensitive recording material comprising an alicyclic, solvent-soluble, thermosetting epoxy oligomer capable of cationic polymerization, the oligomer being of a specified structure, an aliphatic monomer having at least one ethylenically unsaturated bond, the monomer being liquid at normal temperature and pressure, having a boiling point of 100.degree. C. or above at normal pressure and being capable of radical polymerization, a photoinitiator selected from the group consisting of i) a first photoinitiator capable of simultaneously generating a radical species that activates radical polymerization and a Br.o slashed.nsted acid or Lewis acid that activates cationic polymerization, upon exposure to actinic radiation, and ii) a second photoinitiator comprised of a radical polymerization photoinitiator capable of generating a radical species that activates radical polymerization upon exposure to actinic radiation and a cationic polymerization photoinitiator capable of generating a Br.o slashed.

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: A holographic optical element or other similar molded article using glass as a substrate is improved in the adhesion between the glass substrate and a resin layer formed thereon so that neither peeling nor change of properties will occur. A holographic optical element (4) is adapted to generate interference fringes of the same pitch as that of tracks formed on a magnetic recording disk or repeated patterns formed on an encoder by interference between two light beams emerging from two different holographic lens regions. The holographic optical element (4) includes a glass substrate (3), a radiation-cured resin layer (2) having a hologram relief pattern on the surface thereof, and a silane coupling agent layer (5) provided between the glass substrate (3) and the radiation-cured resin layer (2).

Abstract: The invention features methods and systems for thermally fixing or erasing a laser-induced hologram in a photorefractive material, for example, by directing laser radiation having a wavelength through a thickness of the photorefractive material containing the hologram, wherein the wavelength is selected such that the photorefractive material absorbs a portion of the laser radiation and transmits another portion of the laser radiation. The transmitted laser radiation can be redirected back through the hologram, wherein both the laser radiation directed and redirected to the hologram are sufficiently absorbed by the photorefractive material to thermally fix or erase the hologram.

Abstract: Method for producing a of a transparent type hologram screen of an wide visible range. A photosensitive member and a light source of a reference light are arranged on the same side of the light diffusing body. A light source of an object light is arranged on the opposite side of the light diffusing body, so that the light is transmitted through the light diffusing body to generate a object light. A light from a light source of a reference light is reflected at the light diffusing body or a member such as a half mirror or a transparent, reflective hologram element arranged at a front side of the light diffusing body.

Abstract: Surface relief holograms are prepared by directly impressing them into aluminum and other hard metal substrates, without the need to preheat or otherwise soften the substrate. A holographic embossing shim is prepared from a master and possesses a unique combination of surface configuration, hardness, and strength. The embossing shim can be mounted on a cylindrical support. In one embodiment, the shim is used to emboss a hardenable material, which is later hardened to form a tool.

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