In the United States, lighting accounts for 18% of electricity use. Energy efficiency has improved as the lighting industry has shifted from incandescent light bulbs to compact fluorescent lamps to light emitting diodes (LEDs) and other forms of solid state lighting. However, LEDs suffer from a number of drawbacks. To produce a sufficiently bright light source, LEDs are frequently driven at higher current densities, resulting in a loss of efficiency known as a "droop." Currently this loss of efficiency is countered by combining multiple LEDs in one bulb. This method allows each individual LED current to remain low, but increases the system area and cost. Reducing lighting energy consumption will require significant breakthroughs to overcome LED efficiency and cost challenges.
Project Innovation + Advantages:
The University of California, Santa Barbara (UCSB) will develop a gallium nitride (GaN) laser-based white light emitter with no efficiency droop at high current densities. The team's solution will address the efficiency and cost limitations of LEDs. Laser diodes do not suffer efficiency droop at high current densities, and this allows for the design of lamps using a single, small, light-emitting chip operating at high current densities. Using a single chip reduces system costs compared with LEDs because the system uses less material per chip, requires fewer chips, and employs simplified optics and a simplified heat-sink. The chip area required for LED technologies will be significantly reduced using laser-based solid state lighting. This technology will also enable highly controllable beams of light that cannot be achieved with LEDs. The goal of the project is to develop a 1,000 lumen laser-based white light emitter with the efficiency of at least 200 lm/W and a cost of $0.25/klm.
If successful, innovations from this project may dramatically improve lighting technology and lead to an estimated $4 billion in potential savings by 2020.
Expanded use of laser-based solid state lighting could reduce dependence on foreign sources of energy.
Laser-based solid state lighting would reduce the materials and energy required to produce an equal amount of light using current technologies.
Efficiency gains from the use of laser-based solid state lighting may lead to a 4x reduction in cost ($/klm) and $4 billion in potential savings from reduced electricity consumption.