Although white LED lumen output and luminance have both substantially been increased in the last few years, multiple LEDs are still needed, at present time, to meet automotive forward lighting such as low beam headlamp photometric specifications. Use of multiple LEDs in combination with optics is often constrained by the lamp size. With the goal of minimizing the number of LEDs used in an automotive forward lighting design, further studies have been conducted to optimize reflector optics for the fog lamp and headlamp low beam applications. The studies included different types of LEDs by means of lumen output and effective emitting area. In addition, the system etendue ([1]-[3]) and its optical transformations have been taken into considerations in the studies.
