Surface light source device
First Claim
1. A surface light source device comprising:
- a transparent light guiding plate having a first end edge, a second end edge opposite said first end edge, a first side edge, a second side edge opposite said first side edge, a front face and a back face;
a line light source mounted along said first end edge of said light guiding plate;
an end edge reflection layer mounted along said second end edge of said light guiding plate;
a back face reflection layer which is white and is provided on said back face of said light guiding plate;
a light diffusion/transmission section provided on said back face of said light guiding plate;
wherein, in a first region from said first end edge to a first predetermined position between said first and second end edges, a density of said light diffusion/transmission section increases gradually along a first direction perpendicular to said first end edge with an increase in distance from said first end edge; and
wherein, in a second region from said first predetermined position to said second end edge, a density of said light diffusion/transmission section is constant along said first direction.
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Accused Products
Abstract
A surface light source device includes a light guiding plate which is transparent, a line light source provided on one end edge of the light guiding plate, an end edge reflection layer provided on the other end edge of the light guiding plate, and a light diffusion/transmission section provided on a back face of the light guiding plate. A ratio of an area of the light diffusion/transmission section to a whole area of the back face of the light guiding plate gradually increases with an increase in distance from the light source end edge in a region from the end edge on the light source end of the light guiding plate to a position at which a surface emission luminance of the light guiding plate is lowest, and is constant in a region from the position to the other end edge on the end edge reflection layer end of the light guiding plate. A back face reflection layer which is white is provided on the back face of the light guiding plate.
229 Citations
17 Claims
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1. A surface light source device comprising:
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a transparent light guiding plate having a first end edge, a second end edge opposite said first end edge, a first side edge, a second side edge opposite said first side edge, a front face and a back face; a line light source mounted along said first end edge of said light guiding plate; an end edge reflection layer mounted along said second end edge of said light guiding plate; a back face reflection layer which is white and is provided on said back face of said light guiding plate; a light diffusion/transmission section provided on said back face of said light guiding plate; wherein, in a first region from said first end edge to a first predetermined position between said first and second end edges, a density of said light diffusion/transmission section increases gradually along a first direction perpendicular to said first end edge with an increase in distance from said first end edge; and wherein, in a second region from said first predetermined position to said second end edge, a density of said light diffusion/transmission section is constant along said first direction. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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Specification