A White Light Source Excited by Laser Diodes

We developed a compact, high luminance white light source based on nitride semiconductor blue laser diodes (LDs) with yellow phosphor materials. The blue laser light from the LD is focused on the yellow phosphor by an optical lens. As a result, white light is obtained by the mixing of blue laser light and yellow light from the phosphors excited by blue laser light. The luminous flux and the luminance were 250 lm and 270 cd/mm2 at an operating current of 1.2 A. This high luminance is 2.5 times that of a conventional HID light.