Automotive headlamps based on LED sources have made considerable inroads into the market, displacing xenon high-brightness lamps in certain models thanks to their compact size and efficiency.
Most are based on phosphor-converted white LEDs (pc-LEDs), in which LEDs of one color are coated with phosphors of different colors to form white light. Multiple LED chips per package can be used to produce a relatively high-intensity hot-spot in the far-field.
But there is still room for improvement, especially in the luminance and flux provided by these lighting systems.
BMW believes that lasers might hold the answer. It has developed a laser-based light source intended to provide a highly collimated beam of light, able to act as a "high-beam booster" to the main LED-generated headlamp illumination.
"Our design aim was to enable two things: better light function and improved design flexibility," commented project manager Stefan Weber. "Illuminance and beam width are important factors in the improvement of night-time visibility, and we believe that this systems allows both."
The laser system is based around a high-luminance solid-state point-source, used to excite a remote yellow phosphor. BMW employs a high-power multi-mode blue laser diode, with an emitting surface said to be 10,000 times smaller than that of the blue chip in a high-power white pc-LED.
"From an optical engineering standpoint, a laser is the ideal high-luminance source," said BMW's Abdelmalek Hanafi, co-inventor of the system. "The energy surface is small, around 10 microns by 5 microns, BMW laser headlamps show the road ahead
Most are based on phosphor-converted white LEDs (pc-LEDs), in which LEDs of one color are coated with phosphors of different colors to form white light. Multiple LED chips per package can be used to produce a relatively high-intensity hot-spot in the far-field.
But there is still room for improvement, especially in the luminance and flux provided by these lighting systems.
BMW believes that lasers might hold the answer. It has developed a laser-based light source intended to provide a highly collimated beam of light, able to act as a "high-beam booster" to the main LED-generated headlamp illumination.
"Our design aim was to enable two things: better light function and improved design flexibility," commented project manager Stefan Weber. "Illuminance and beam width are important factors in the improvement of night-time visibility, and we believe that this systems allows both."
The laser system is based around a high-luminance solid-state point-source, used to excite a remote yellow phosphor. BMW employs a high-power multi-mode blue laser diode, with an emitting surface said to be 10,000 times smaller than that of the blue chip in a high-power white pc-LED.
"From an optical engineering standpoint, a laser is the ideal high-luminance source," said BMW's Abdelmalek Hanafi, co-inventor of the system. "The energy surface is small, around 10 microns by 5 microns, BMW laser headlamps show the road ahead
