Patent ID: 7806538
Filing Date: 2010-10-05
Classification: F21S,F21V,F21W,F21Y

Abstract:
1. A light source device configured to emit light along an optical axis comprising: a light guide member having a flat plate-like shape and made of a material transparent in a visible range, the light guide member having a front surface serving as a light emission surface and a rear surface opposed to the front surface and having a luminance control element configured to control a luminance distribution on the light emission surface, the front surface and rear surface separated by at least one end surface; and a light source including at least one of a point light source and a linear light source facing the at least one end surface of the light guide member, wherein the luminance control element is configured to control light reaching the luminance control element from the at least one end surface of the light guide member and to configure the light into the luminance distribution of light on the light emission surface, the luminance distribution configured to form a light distribution pattern to be projected, the light guide member is configured to emit, from the light emission surface, only parallel polarized light out of the total light emitted from the light source, the parallel polarized light being p-polarized with a plane of vibration parallel to a plane that contains the optical axis and is normal to a surface that is to be illuminated, wherein the light guide member is provided with a stretched polymer film thereinside or thereon, the stretched polymer film having elliptically-shaped small areas of different refractive index so as to show selective polarization and diffusibility.