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US 12,650,609 B2Granted
Optical deflection device, image display device, signal device, image recording medium, and image reproduction method
AssigneeArtience Lab Inc.
InventorAkira Shirakura
Life of this patent
Estimating the term…
Abstract
This optical deflection device has a light source light-emitting units, a transparent medium, and a holographic diffraction grating disposed on the transparent medium without air interposed therebetween, the optical deflection device being configured so that divergent rays incident on the transparent medium from the light source light-emitting units are made parallel by the holographic diffraction grating and propagated at a critical angle in the transparent medium. By combining this optical deflection device with an edge-lit-reproduction-type hologram, it is possible to realize a low-cost, compact image display device, signal device, or the like.
Claims5
An optical deflection device, comprising:
- a plurality of light sources of SMD type LEDs arrayed and wired on a substrate in a form of a tape,
- a transparent medium consisting of a parallel flat plate with optical refractive index of at least 1.3 or greater,
- a plurality of holographic diffraction gratings placed on a part of the same surface of the transparent medium without an air gap between the holographic diffraction gratings and the transparent medium and arranged without interposition of any gap between adjacent holographic diffraction gratings in a direction perpendicular to a light-guiding direction of the parallel light in the transparent medium,
- a spacer interposed between the transparent medium and the substrate, configured to position each light source of LEDs to face center of each holographic diffraction grating in proximity maintaining a specified distance, and
- barrier walls of light absorbing material placed between neighboring holographic diffraction gratings in a manner which prevents incidence of light from the light sources into the neighboring diffraction gratings, wherein
- each light source is positioned to face each of the holographic diffraction gratings and has a same angle of divergence and same emission wavelength components,
- each holographic diffraction grating deflects a diverging light incident from each light source into parallel light at a specified angle in excess of a critical angle of the transparent medium, causing it to propagate within the transparent medium, and
- a surface of the substrate on which the LEDs are arrayed is parallel to and faces a surface perpendicular to a thickness direction of the parallel flat plate for light emitting locus of the LEDs to be away from a surface in the thickness direction of the parallel flat plate.
5 more elements
An image reproduction method for viewing a hologram image, comprising:
- attaching, without interposition of an air gap, an edge-lit hologram produced by a separate process on to the face of a transparent medium of optical refractive index 1.3 or greater that is a thin cylinder or a partial thin cylinder with curvature,
- illuminating with at least two light sources and holographic diffraction gratings or refractive optical functional elements facing each light source and barrier walls of light absorbing material placed in a manner which prevents incidence of light from the light sources into neighboring holographic diffraction gratings or refractive optical functional elements,
- using the holographic diffraction gratings or refractive optical functional elements to make light from the light sources to be incident to the transparent medium at an angle in excess of a critical angle of the transparent medium, and
- making the edge-lit hologram to be illuminated by light propagating inside the transparent medium to reproduce a hologram image,
- wherein the light sources are SMD type LEDs arrayed and wired on a substrate in the form of a tape,
- a surface of the substrate on which the LEDs are arrayed is parallel to and faces a surface perpendicular to a thickness direction of the cylinder for the light emitting locus of the LED is to be away from a face of the cylinder in the thickness direction of the cylinder,
- a spacer allows each of all light sources of LEDs to face the center of each of the holographic diffraction gratings or the refractive optical functional elements in proximity maintaining a specified distance, and the spacer being placed between the transparent medium and the substrate arrayed the light sources, and
- a length y of the parallel light deflected by the holographic diffraction grating in the propagation direction is defined by an equation y=2t×tan θ, where θ is a propagation angle of the parallel light relative to a normal surface of the transparent medium, and t is the thickness of the transparent medium.
5 more elements
Dependencies are inferred from the claim text.