| 摘要 |
PURPOSE:To emit high-luminance light uniformly only within a desired angle range and to obtain surface light emission having no dispersion in luminance by forming a light diffusion sheet of a transparent base material which does not contain light diffusing agent particles and specifying the display roughness of the random infinitesimal uneven surface of its top surface. CONSTITUTION:The device consists of a light guide plate 1, a light reflecting layer 2, a light source (unit) 3, a lens sheet 4, a reflecting mirror 5, a transmission type display device 6 such as a liquid crystal display device, a light diffusion sheet 8, and a gap 9. Further, projections 41 are provided on the top surfaces of the light diffusion sheet 8 and those projections 41 are obtained by forming a random uneven cross-sectional shape (e.g. sand pattern and aventurine pattern) over the entire top surface of the light diffusion sheet 8. Then the light diffusion sheet 8 in use is formed of the light transmissive base material, which contains no light diffusing agent particle. Further, the height of the projection group 41 formed on the top surface of the light diffusion sheet 8 is set to larger than the wavelength of light source light and <=100mum. |
