Patent ID: 7556391
Filing Date: 2009-07-07
Classification: G02B,G02F

Abstract:
1. A transmittance adjuster unit that is provided on a side closer to a light emission plane of a light guide plate of a planar illumination device, wherein the planar illumination device has at least a light source and the light guide plate that causes light incident from the light source to emit from the light emission plane thereof, said transmittance adjuster unit comprising: multiple transmittance adjusters arranged in a predetermined pattern to receive light from the light emission plane, wherein a pattern density of the transmittance adjusters at a predetermined position (x,y) is p(x,y), wherein a relative luminance F(x,y) is a ratio of a luminance of light emitted from the predetermined position (x,y) of a light emission plane of the planar illumination device when the transmittance adjuster unit is not provided to a maximum luminance of light emitted from the light emission plane of the planar illumination device when the transmittance adjuster unit is not provided, wherein the relationship between the relative luminance F(x,y) and the pattern density of the transmittance adjusters p(x,y) satisfies the following expression: wherein c satisfies 0.5≦c≦1 and F