| 摘要 |
PROBLEM TO BE SOLVED: To provide an inexpensive surface light source device capable of obtaining high luminance with less reflection loss by forming a silicone oxide layer as an antireflection film on the incident plane and/or the outgoing plane of at least either of a light transmission plate and a diffusion plate. SOLUTION: The light generated by the linear light source 4 is made incident on the light transmission plate 2 from the side face of the plate 2. The incident light passes through the light transmission plate 2, the light passes through the plate 2 while partly outgoing from the outgoing plane side, then, the light advances toward a side face opposite to the linear light source 4, then, the light is emitted on the whole outgoing plane. After the light outgoing from the plate 2 is diffused by the diffusing plate body 1, the light is condensed by a prism sheet 5, then, the liquid crystal display screen is irradiated with the light. In this case, the silicone oxide layer is installed on the rear side of the diffusing plate body 1. When the light outgoing from the plate 2 passes through the diffusing plate body 1, the reflection loss of the light with a specified wavelength corresponding to the film thickness is suppressed by the presence of the silicone oxide layer, then, the light transmission efficiency is enhanced as much as the suppression of the loss. Thus, the high luminance is obtained, and in the case of requiring the same luminance, the device is used at a low power. |
