Planar light source unit and display device
First Claim
1. A planar light source unit comprising:
- a light source;
a light guide plate having a light incident surface through which light from the light source enters, a light exit surface through which light exits, and an anisotropic diffraction grating formed on the light exit surface or a surface opposite to the light exit surface for diffusing light in a principal diffusing direction along the light incident surface; and
a prism sheet for collecting light traveling from the light incident surface to an opposite side surface, having a plurality of prism structures on a surface opposite to the light exit surface, each of the plurality of prism structures having an apex angle of larger than 65 degrees and smaller than 68 degrees,wherein the anisotropic diffraction grating does not substantially diffuse light in a direction perpendicular to the principal diffusing direction.
2 Assignments
0 Petitions
Accused Products
Abstract
A light guide plate has a hologram pattern on a light exit surface. The hologram pattern anisotropically diffuses light in the direction parallel with a light incident surface of the light guide plate. On a back surface of the light guide plate are formed mirror-polished prism structures extending parallel with the light incident surface. A downward-pointing prism sheet with a given prism apex angle is placed on the light exit surface of the light guide plate. The use of the downward-pointing prism sheet together with the light guide plate having the anisotropic diffusion hologram pattern integrally formed thereon produces a liquid crystal display device with enhanced luminance properties.
75 Citations
16 Claims
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1. A planar light source unit comprising:
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a light source; a light guide plate having a light incident surface through which light from the light source enters, a light exit surface through which light exits, and an anisotropic diffraction grating formed on the light exit surface or a surface opposite to the light exit surface for diffusing light in a principal diffusing direction along the light incident surface; and a prism sheet for collecting light traveling from the light incident surface to an opposite side surface, having a plurality of prism structures on a surface opposite to the light exit surface, each of the plurality of prism structures having an apex angle of larger than 65 degrees and smaller than 68 degrees, wherein the anisotropic diffraction grating does not substantially diffuse light in a direction perpendicular to the principal diffusing direction. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A display device, comprising:
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a planar light source unit; and a display panel displaying images by controlling transmission of light from the planar light source unit; the planar light source unit comprising; a light source; a light guide plate having a light incident surface through which light from the light source enters, a light exit surface through which light exits, and an anisotropic diffraction grating formed on the light exit surface or a surface opposite to the light exit surface for diffusing light in a principal diffusing direction along the light incident surface; and a prism sheet for collecting light traveling from the light incident surface to an opposite side surface, having a plurality of prism structures on a surface opposite to the light exit surface, each of the plurality of prism structures having an apex angle of larger than 65 degrees and smaller than 68 degrees wherein the anisotropic diffraction grating does not substantially diffuse light in a direction perpendicular to the principal diffusing direction. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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Specification