| 摘要 |
PROBLEM TO BE SOLVED: To make in-surface luminance uniform and widen effective light emission area, and obtain a uniform light emission surface with a small number of LEDs by providing two kinds of diffusion surface. SOLUTION: The 1st light diffusion surface 11 is given gradations so that the rate of coating with a white material per unit area is low at the part where the luminance of LEDs 1 is high and high at the part of the luminance of the LEDs 1 is low. Namely, when plural LEDs are arranged on a straight line, parts between the LEDs become dark, so the light emission surfaces nearby the LEDs are made uniform in luminance by the light diffusion surface having the high rate of coating. Then the 2nd light diffusion surface 12 have gradations printed so that the rate of coating with the white material increases with the distance from the LEDs 1, and this 2nd light diffusion surface 12 diverges the LED light uniformly over the entire light guide plate. Therefore, a line source need not be formed by arraying many LEDs, and the uniform light emission surface can be obtained with a small number of LEDs. |
