| 摘要 |
PURPOSE:To improve light emission efficiency, to reduce uneven illuminance, and to stabilize illuminance by converging light by preventing diffusion in a direction intersecting orthogonally to the longitudinal direction of the light occurring by a projecting part, and diffusing the light only in the longitudinal direction by the projecting part. CONSTITUTION:Since the light emitting plane 17 of a light source body 15 is formed in Fresnel lens shape having plural projecting parts 18a and recessed parts 18d, a luminance flux in a direction of Y intersecting orthogonally to the longitudinal direction X of a printed circuit board 16 out of the light emitted from a light emitting element 10 is converged by the convex lens action of the projecting part 18a on the light emitting plane 17, and the luminance flux in the longitudinal direction X is diffused by the concave lens action of the recessed part 18b. In other words, the light emitted in the longitudinal direction X of the printed circuit board 16 from the light emitting element 10 in the direction Y intersecting orthogonally to the longitudinal direction X of the printed circuit board 16 can be converged by preventing the diffusion of it by the projecting part 18a, and it can be diffused only in the longitudinal direction X by the recessed part 18b. In such a way, the light emission efficiency can be improved, and the uneven illuminance can be reduced, which stabilizes the illuminance. |
