| 摘要 |
PURPOSE:To save electric power and obtain an easy-to-see liquid crystal surface by making the peak of light distribution characteristics of a light source provided to the rear surface of a transmission type liquid-crystal element coincident with the center of the field of view of the liquid-crystal display surface. CONSTITUTION:The illumination light source consisting of a diffusing plate 4, light guide 3, and fluorescent tube 2 is formed on the rear surface of the transmission type liquid-crystal element 1. The light guide 3 is formed on acrylic resin and one surface of forming a plane light source is formed as shown by a saw-tooth section 5. The tilt angle of the saw-tooth section 5, direction of the light guide 3, arrangement of the fluorescent tube 2, and diffusibility of the diffusion plate 4 and whether it is present or not are adjusted so that the center of the light distribution is set in the direction wherein the light distribution characteristics are nearly coincident with visual angle characteristics. A view angle area 7 having >=5 contrast on the liquid-crystal display element is constituted nearly as shown by a broken line. Thus, electric power for illumination is save and visibility in a view angle direction is improved. |
