| 摘要 |
PROBLEM TO BE SOLVED: To effectively increase the quantity of an incident light while suppressing a production cost without an adhesion by arranging a prismatic transparent body on one planar surface of a light transmission plate in the incident end part of the plate being thinner than the diameter of a light source and forming a fine structure part on the opposing surface of light transmission plate of the transparent body. SOLUTION: The prismatic transparent body 3 is arranged on one planar surface of the light transmission plate 2 in the incident end part of the thin light transmission plate 2 and the fine structure part 4 is formed on the opposing surface of the plate 2 of the body 3. The plate 2 where the incident end surface is opposed to the light source 1 is thinner than the diameter D of the source 1 and optically formed of an optical transparent material. The fine structure part 4 is formed by coarse conversion by a sand blast, for example, on the opposing surface of the plate 2 of the part 3. Thus, the light made incident on the body 3 is reflected against the part 4 and a part of it enters into the plate 2. The quantity of the incident light is effectively increased while suppressing the production cost without adhering the body 3 onto the plate 2 or providing a means for eliminating a boundary surface by integral molding. |
