Lasers could replace LEDs for lighting

Sandia Labs and BMW suggest lasers could be an alternative to LED-based systems

Sandia conducted tests into the white light generated by diode lasers and discovered the human eye is as comfortable with it as it is with LEDs.

An important difference between lasers and LEDs is the efficiency of each, with LEDs reducing in efficiency at higher currents while lasers improve.

diode lasers are a worthwhile path to peruse for lighting

The tests – reported in LEDs Magazine – took place at University of New Mexico’s Centre for High Technology Materials, where 40 volunteers were seated in front of two near-identical scenes. Each both was illuminated by warm, cool or neutral white LEDs, tungsten-filament incandescent light or a combination of four lasers – blue, red, green, yellow – which combined were tuned to create white light.

Volunteers were asked to chose between alternatives – but were not told which source was being used – 80 times. Jonathan Wierer, involved in planning, calibrating and executing the experiments, said there was a significant preference for the diode-laser-based white light over the warm and cool LED-based white light. There was no statistical preference between the laser-based light and either the neutral LED-based or incandescent white light.

Comparing laser light with an incandescent bulb

Sandia’s experiment combined the output of four laser colours – blue, red, green and yellow – to create a white light source. The narrow beam is addressed via a suitable optical system.

Driving possibilitiesAt the same time as Sandia’s research, BMW demonstrated a prototype laser-based headlight system on its i8 Concept car, using blue lasers and phosphors.

BMW used blue lasers to illuminate a remote phosphor system, generating white light.

Driver safety needs to be addressed, insuring lasers are properly directed. BMW said the laser headlamps would be safe, as the illumination would be indirect.