Light source device and vehicle lighting device

摘要

An LED light source device (10, 50, 60, 70, 80) and an illumination device or a vehicle lighting device (20, 30, 40) using the same are provided, and the LED light source device has a light weight and thin profile and can form a desired light distribution pattern with a simple configuration. The light source device (10) can include: a plate shape light guide member (11) made of a material that is transparent in a visible range, the light guide member (11) having a front surface serving as a light emitting surface (11b) with a platy shape and a rear surface having a luminance control element (14) for controlling a luminance distribution on the light emitting surface (11b); and a point or linear light source (12) facing to an end surface (11a) of the light guide member (11), wherein the luminance control element (14) controls light reaching the element (14) from the end surface (11a) of the light guide member (11) and configures the luminance distribution on the light emitting surface (11b), the luminance distribution being obtained by reducing a light distribution pattern to be projected (and in some cases horizontally and vertically reversing the pattern).