LIGHT GUIDE PLATE, LIGHT GUIDE PLATE UNIT, AND PLANAR LIGHTING DEVICE
First Claim
1. A light guide plate comprising:
- a light exit plane being flat and rectangular;
two light entrance planes respectively containing two opposite longer sides of said light exit plane and disposed opposite each other;
two inclined rear planes being symmetrical and increasingly distanced from said light exit plane from said two light entrance planes toward a center of said light exit plane;
a curved portion joining said two inclined rear planes; and
scattering particles for scattering light travelling inside said light guide plate contained in said light guide plate,wherein a light guiding length between said two light entrance planes ranges from 480 mm to 500 mm both inclusive,wherein a particle diameter of said scattering particles ranges from 4.0 μ
m to 12.0 μ
m both inclusive and a particle density of said scattering particles ranges from 0.02 wt % to 0.22 wt % both inclusive;
wherein said particle diameter and said particle density of said scattering particles are within an area determined by six points (4.0,0.015), (4.0,0.065), (7.0,0.02), (7.0,0.09), (12.0,0.035), and (12.0,0.16) in a graph where a horizontal axis indicates said particle diameter [μ
m] of said scattering particles and a vertical axis indicates said particle density [wt %] of said scattering particles;
wherein a light use efficiency indicating a ratio of light emitted through said light exit plane to light admitted through said two light entrance planes is 55% or greater; and
wherein a middle-high ratio represented by a brightness distribution at said light exit plane indicating a ratio of brightness of light emitted from an area about a center of said light exit plane to the brightness of light emitted at areas of said light exit plane close to said light entrance planes is above 0% and not greater than 25%.
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Accused Products
Abstract
The light guide plate includes a light exit plane, two light entrance planes, two symmetrical inclined rear planes increasingly distanced from the light exit plane from the two light entrance planes toward a center of the light exit plane, a curved portion joining the two inclined rear planes and scattering particles for scattering light travelling inside the light guide plate. The light guide plate satisfies given ranges set for a length between the two light entrance planes, a thickness of each of the two light entrance planes, a thickness at the center of the curved portion, a radius of curvature thereof, tapers of the inclined rear planes, and a particle diameter and a density of the scattering particles, and conditions that a light use efficiency be 55% or greater and that a middle-high ratio represented by the brightness distribution at the light exit plane be greater than 0% and not greater than 25%.
43 Citations
20 Claims
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1. A light guide plate comprising:
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a light exit plane being flat and rectangular; two light entrance planes respectively containing two opposite longer sides of said light exit plane and disposed opposite each other; two inclined rear planes being symmetrical and increasingly distanced from said light exit plane from said two light entrance planes toward a center of said light exit plane; a curved portion joining said two inclined rear planes; and scattering particles for scattering light travelling inside said light guide plate contained in said light guide plate, wherein a light guiding length between said two light entrance planes ranges from 480 mm to 500 mm both inclusive, wherein a particle diameter of said scattering particles ranges from 4.0 μ
m to 12.0 μ
m both inclusive and a particle density of said scattering particles ranges from 0.02 wt % to 0.22 wt % both inclusive;wherein said particle diameter and said particle density of said scattering particles are within an area determined by six points (4.0,0.015), (4.0,0.065), (7.0,0.02), (7.0,0.09), (12.0,0.035), and (12.0,0.16) in a graph where a horizontal axis indicates said particle diameter [μ
m] of said scattering particles and a vertical axis indicates said particle density [wt %] of said scattering particles;wherein a light use efficiency indicating a ratio of light emitted through said light exit plane to light admitted through said two light entrance planes is 55% or greater; and wherein a middle-high ratio represented by a brightness distribution at said light exit plane indicating a ratio of brightness of light emitted from an area about a center of said light exit plane to the brightness of light emitted at areas of said light exit plane close to said light entrance planes is above 0% and not greater than 25%. - View Dependent Claims (5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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2. A light guide plate comprising:
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a light exit plane being flat and rectangular; two light entrance planes respectively containing two opposite longer sides of said light exit plane and disposed opposite each other; two inclined rear planes being symmetrical and increasingly distanced from said light exit plane from said two light entrance planes toward a center of said light exit plane; a curved portion joining said two inclined rear planes; and scattering particles for scattering light travelling inside said light guide plate contained in said light guide plate, wherein a light guiding length between said two light entrance planes ranges from 515 mm to 620 mm both inclusive, wherein a particle diameter of said scattering particles ranges from 4.0 μ
m to 12.0 μ
m both inclusive and a particle density of said scattering particles ranges from 0.015 wt % to 0.16 wt % both inclusive;wherein said particle diameter and said particle density of said scattering particles are within an area determined by six points (4.0,0.015), (4.0,0.065), (7.0,0.02), (7.0,0.09), (12.0,0.035), and (12.0,0.16) in a graph where a horizontal axis indicates said particle diameter [μ
m] of said scattering particles and a vertical axis indicates said particle density [wt %] of said scattering particles;wherein a light use efficiency indicating a ratio of light emitted through said light exit plane to light admitted through said two light entrance planes is 55% or greater; and wherein a middle-high ratio represented by a brightness distribution at said light exit plane indicating a ratio of brightness of light emitted from an area about a center of said light exit plane to the brightness of light emitted at areas of said light exit plane close to said light entrance planes is above 0% and not greater than 25%.
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3. A light guide plate comprising:
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a light exit plane being flat and rectangular; two light entrance planes respectively containing two opposite longer sides of said light exit plane and disposed opposite each other; two inclined rear planes being symmetrical and increasingly distanced from said light exit plane from said two light entrance planes toward a center of said light exit plane; a curved portion joining said two inclined rear planes; and scattering particles for scattering light travelling inside said light guide plate contained in said light guide plate, wherein a light guiding length between said two light entrance planes ranges from 625 mm to 770 mm both inclusive, wherein a particle diameter of said scattering particles ranges from 4.0 μ
m to 12.0 μ
m both inclusive and a particle density of said scattering particles ranges from 0.01 wt % to 0.12 wt % both inclusive;wherein said particle diameter and said particle density of said scattering particles are within an area determined by six points (4.0,0.01), (4.0,0.05), (7.0,0.01), (7.0,0.06), (12.0,0.02), and (12.0,0.12) in a graph where a horizontal axis indicates said particle diameter [μ
m] of said scattering particles and a vertical axis indicates said particle density [wt %] of said scattering particles;wherein a light use efficiency indicating a ratio of light emitted through said light exit plane to light admitted through said two light entrance planes is 55% or greater; and wherein a middle-high ratio represented by a brightness distribution at said light exit plane indicating a ratio of brightness of light emitted from an area about a center of said light exit plane to the brightness of light emitted at areas of said light exit plane close to said light entrance planes is above 0% and not greater than 25%.
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4. A light guide plate comprising:
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a light exit plane being flat and rectangular; two light entrance planes respectively containing two opposite longer sides of said light exit plane and disposed opposite each other; two inclined rear planes being symmetrical and increasingly distanced from said light exit plane from said two light entrance planes toward a center of said light exit plane; a curved portion joining said two inclined rear planes; and scattering particles for scattering light travelling inside said light guide plate contained in said light guide plate, wherein a light guiding length between said two light entrance planes ranges from 785 mm to 830 mm both inclusive, wherein a particle diameter of said scattering particles ranges from 4.0 μ
m to 12.0 μ
m both inclusive and a particle density of said scattering particles ranges from 0.008 wt % to 0.08 wt % both inclusive;wherein said particle diameter and said particle density of said scattering particles are within an area determined by six points (4.0,0.008), (4.0,0.03), (7.0,0.009), (7.0,0.04), (12.0,0.02), and (12.0,0.08) in a graph where a horizontal axis indicates said particle diameter [μ
m] of said scattering particles and a vertical axis indicates said particle density [wt %] of said scattering particles;wherein a light use efficiency indicating a ratio of light emitted through said light exit plane to light admitted through said two light entrance planes is 55% or greater; and wherein a middle-high ratio represented by a brightness distribution at said light exit plane indicating a ratio of brightness of light emitted from an area about a center of said light exit plane to the brightness of light emitted at areas of said light exit plane close to said light entrance planes is above 0% and not greater than 25%.
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Specification