| 摘要 |
PURPOSE:To provide a light-guiding board of a thinner form and of a much higher luminous efficiency, by employing a molded product which has prisms composed of fine unevenness formed on its light-emitting surfaces in a planar light-emitting apparatus. CONSTITUTION:Fine unevenness is formed on the light-emitting surface 20A of a light-guiding board 20, and the fine unevenness acts as prisms which give a directional pattern to rays of light emitted from the light-emitting surface 20A. Heights h of projecting parts composing prisms range from 10 to 100mum and intervals between projecting parts range from 5 to 100mum. Fine unevenness is also formed on the reflecting surface 20B of the light-guiding board 20, and the fine unevenness acts as prisms which give a directional pattern to rays of light reflected by the reflecting surface 20B. The unevenness-made prisms on the light-emitting surface 20A and the reflecting surface 20B are formed in one body with the light-guiding board 20, and are easily manufactured by molding. Rays of light in the useful direction thereby increase, utilization rate of light becomes higher, and a high luminance is gained with a relatively small amount of input power. |
