| 摘要 |
PURPOSE:To prevent excessive light from being made incident on a transparent substrate effectively by covering the surface of the common transparent substrate with a light shield layer except distributed index lens parts. CONSTITUTION:A mask 12 which has a circular window or hole 12a is formed in the center of the transparent substrate 11 made of a dielectric such as synthetic resin and glass. Then diffusion sources 10 are diffused in the substrate 11 through the hole 12a to form a specific refractive index distribution in the substrate 1. When a parallel light beam 14 is made incident on the surface of this lens body, the light beam 14 is converged on a focus in a spot shape at a distributed index lens part 13. Then when the parallel light beam 14 is made incident on the surface 11a of the lens body, the light shield layer 12 cuts off light to be made incident on the transparent substrate 11 from the surface 11a except the distributed index lens part 13. Consequently, the excessive light is prevented prevented from being made incident on the transparent substrate 11. |
