Applied Sciences (Oct 2020)

A Study of High-Efficiency Laser Headlight Design Using Gradient-Index Lens and Liquid Lens

  • Yi-Chin Fang,
  • Yih-Fong Tzeng,
  • Chan-Chuan Wen,
  • Chao-Hsien Chen,
  • Hsiao-Yi Lee,
  • Shun-Hsyung Chang,
  • Yi-Lun Su

Journal volume & issue
Vol. 10, no. 20
p. 7331


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In the field of vehicle lighting, due to the diode laser, its small size and high energy conversion efficiency, it can be effectively used as the headlight source of high beam. In recent years, it was adopted by European advanced car manufacturers as a new generation of automotive headlight lighting products. The current mature technology on the market is to extend the laser beam by means of reflection and to use a single high-power laser as the light source to meet the needs of surface lighting. In this research, we propose a new integrated optical design for an automotive headlight system with the rod lens, gradient-index lens (GRIN lens) and freeform lens to expand the laser beam. With regard to the diffusion of the beam by reflection and refraction, the liquid lens is used as a switch for the high beam and low beam lights to meet the needs of vehicle lighting functions and to use low-power diode lasers to synthesize the array light source. Compared with the 24-W LED headlight module available in the current market, the energy saved by this proposed optical design can increase efficiency by an average of 33%. The maximum illuminance is 56.6 lux in the high-beam mode, which is 18% higher than the standard value. Let the laser light meet the lighting requirements of regulatory standard values even beyond.