| 摘要 |
PROBLEM TO BE SOLVED: To obtain a surface light source device which is substantially free from reflection loss, has high sensitivity and is inexpensive by affixing a low-reflection film to at least one light transparent boundary of a light transmission plate and a diffusion plate. SOLUTION: The low-reflection film 1 is affixed to at least one light transparent boundary of the light transmission plate 2 and the diffusion plate 10. Namely, the back light of a liquid crystal display device has the light transmission plate 2, the light source 4 of a cold cathode ray tube, etc., for making light incident from the light incident end face of this plate and the reflection plate 3 which is disposed on the rear surface side of the light transmission plate 2 and reflects the light emitted from the rear surface of the light transmission plate 2. The diffusion plate 10 is composed of a diffusion plate body 11 disposed on the exit light surface side of the light transmission plate 2 and two prism sheets (condenser sheets) 5 which are disposed on the exit light surface side thereof and impart a light condensing effect, etc., thereto. Further, the device has a reflection cover 9 which reflects the rays from a linear light source 4 and makes the rays incident on the light transmission plate 3 from its light incident end face. The low-reflection film 1 is stuck to the incident light surface of the diffusion plate body 11. |
