Abstract:
Systems and methods for creating an autostereoscopic display include a holographic optical element (HOE) recorded using coherent light divided into diverging reference and object beams that illuminate the HOE from opposite sides. The object beam passes through first and second diffusers with one diffuser being a directional diffuser to more uniformly illuminate the HOE. Optic elements may be used to more closely match beam diameters and/or profiles of the recording wavelengths. Baffles may be positioned on opposite sides of the HOE with openings aligned proximate the reference beam and object beam paths, respectively, to reduce stray reflections and provide ambient air flow attenuation or damping. One or more edges of the HOE are masked to reduce or prevent stray light from entering and reflecting within the HOE during recording.
Abstract:
A discrimination medium, which can have much information, can be produced on a small scale at low cost, and enables change of a sticker design at low cost, is provided. The discrimination medium includes an optically transparent first substrate on which a cholesteric liquid crystal layer is formed, the cholesteric liquid crystal layer being formed with a fine asperity used for displaying a hologram, an optically transparent second substrate on which a print layer is formed, the print layer having a predetermined pattern made of ink and having a transparent portion without the ink of the pattern around the pattern, the pattern reflecting or absorbing a light of a predetermined wavelength, and a transparent adhesive layer, wherein the optically transparent first substrate, the optically transparent second substrate, and the transparent adhesive layer, are disposed in turn from a side checked visually.
Abstract:
Technologies are generally described for reproducing holographic images by causing a photo-induced change in the diffractive index of a holographic recording medium. An example device may include a light irradiation unit and a transparent substrate. The light irradiation unit can be configured to transmit a photo-inducing light. Further, the transparent substrate may have a predetermined refractive index and can be configured to include a first surface and a second surface opposite the first surface. The first surface can be configured to receive an incident light, and the second surface can be configured to receive the photo-inducing light. The transparent substrate can be configured to form interference fringe patterns from a photo-induced change in the refractive index of the transparent substrate responsive to the photo-induced light.
Abstract:
A discrimination medium, which can have much information, can be produced on a small scale at low cost, and enables change of a sticker design at low cost, is provided. A cholesteric liquid crystal layer, having a fine asperity for forming a hologram, is formed on a transparent first substrate. A print layer composed of a black ink is formed on a transparent second substrate. The substrates are affixed to each other via a bond layer, so that a discrimination medium is obtained. In the discrimination medium, the display content obtained by the print layer is changed, so that the display content for discrimination can be changed at low cost.
Abstract:
A security device has a support substrate of a first material having a softening temperature t1 and an embossed layer of a second different material supported by the support substrate having a softening temperature t2, wherein t2
Abstract:
An object of the present invention is to provide a discrimination medium which has high discrimination ability, and which is more difficult to counterfeit than conventional discrimination mediums. A discrimination medium comprises: a cholesteric liquid crystal layer; and a liquid crystal layer acting as a half-wave plate and provided on the cholesteric liquid crystal layer in a predetermined pattern.
Abstract:
Provided is a transmission-type volume hologram recording medium for use in a two-beam hologram recording system, which has a high diffraction efficiency and is capable of significantly reducing the intensity of higher-order diffracted light, which causes a noise, than first-order diffracted light.The transmission-type volume hologram recording medium includes two facing substrates of dissimilar materials and, held between them, a volume hologram recording layer of a volume hologram recording photosensitive composition. The substrates holding the volume hologram recording layer therebetween preferably have transparency in the visible light region and have thicknesses each from 2 to 2000 μm. The difference in refractive index between the two substrates holding the volume hologram recording layer therebetween is preferably from 0.001 to 0.5. The difference in thickness between the two substrates holding the volume hologram recording layer therebetween is preferably from 1 to 1500 μm.
Abstract:
The present invention provides a computer generated hologram which forms a light intensity distribution on a predetermined plane by giving a phase distribution to a wavefront of incident light, comprising an anisotropic layer whose refractive index with respect to linearly polarized light in a first direction is different from a refractive index of the anisotropic layer with respect to linearly polarized light in a second direction perpendicular to the linearly polarized light in the first direction, and an isotropic layer whose refractive index with respect to the linearly polarized light in the first direction is equal to a refractive index of the isotropic layer with respect to the linearly polarized light in the second direction.
Abstract:
A means for optically coupling a semiconductor laser to an optical fiber is disclosed. In one embodiment, a volume phase holographic element is disposed on a light-emitting surface of a semiconductor laser. The volume phase holographic element acts as an aberration-corrector for a lens that is disposed between the semiconductor laser and the optical fiber. In this way, an inexpensive lens that is not aberration free can be used. In some embodiments, the volume phase holographic element converts a Gaussian light beam emitted by the semiconductor laser into an annular beam that is more suitable for long distance transmission in multimode fibers.
Abstract:
A method of digitally processing light waves passing through a planar structure having given functions ƒin(x, y, ω) and ƒout(x, y, ω) and consisting of a light-propagating and distributing layer is provided. This layer contains a plurality of interconnecting pattern elements of a holographic pattern and a plurality of planar optical elements arranged in a predetermined pattern on the aforementioned light-propagating and distributing layer. The method consists of calculating positions and shapes of the interconnecting pattern elements of the holographic pattern based on the aforementioned given functions by solving an inverse problem. The interconnecting pattern elements have refractive indices different from the refractive indices of the light-propagating and distributing layer and are manufactured on the basis of the results of the calculations. The aforementioned continuous function is digitized, and the obtained digitized planar holographic pattern is used for converting the function ƒin(x, y, ω) into the function ƒout(x, y, ω).