| 摘要 |
PROBLEM TO BE SOLVED: To increase the amount of light emitted outside of a light guide plate held at a distance from a light source, if the density of recesses provided in the light guide plate is given stepless differences, by preventing the recesses from fluctating in shape with positions, and making the intervals between the adjacent recesses smaller for an increase in the density at which the recesses are arranged. SOLUTION: This surface light emitting device has a light source placed on one or both sides of a light-transmitting light guide plate 1 and provides illumination by introducing the light of the light source into the light guide plate and causing the light to be scattered by diffusers arranged parallel to each other on a light emitting surface. In this case, projecting dies 103 for forming a number of recesses 6 on the back opposite to the light emitting surface in a high density roughly proportional to the distance from the light source are injection molded from a light-transmitting resin material using a molding die 101 obtained from a matrix M machined by a cutting tool 30 having an apex angle θ. |
