| 摘要 |
PROBLEM TO BE SOLVED: To provide a light transmission plate of which the obverse side and the reverse side are easily decided and further which can be positioned on a frame member without arranging lobes which make the shapes, density, forming positions or the like of dots difficult to design. SOLUTION: In the light transmission plate of which the obverse of a square plate-like body is made into a light emitting surface, the reverse of it is made into a light reflecting surface and one side face is made into a light incident surface making light from the light source incident thereon, the light reflecting surface is provided with a dot non-formative region with no dot formed on the outer peripheral part and a dot forming region is provided with protruding parts protruding in a direction vertical to the light reflecting surface on a region placed in contact with a side face confronting the light incident surface, where the protruding part is in 0.5-2.0 mm height range and the outer periphery of the base fits into a toric region with 0.5 mm internal diameter and 2.0 mm external diameter. |
