Efficient light and beam sources with LEDs and semiconductor lasers

摘要

The brightness improvement of highly efficient LEDs with InGaAlP and InGaN materials enables completely new applications in automotive industry, in digital imaging, in signal technology and in general lighting. On a production level, a luminous flux conversion efficacy of 20 to 30 lm/W is mastered for red through green today. Engineering samples with red have just achieved values of 100 lm/W. Blue emitting diodes show about 6 lm/W which can be used to generate white, reaching 20 lm/W by luminescence conversion. Single-color LEDs should be improved to a luminous flux conversion efficacy approaching 100 lm/W in the next few years. White LEDs should exceed 50 lm/W. With 30 mW output at 60 ℃, the blue lasers will meet the full DVD specification in a short term. Red lasers already meet the requirements for their application in laser projection. Powerful light beam sources for projections in the blue and green region can be implemented by frequency conversion in the medium term. This technique can be based on the InGaAs technology, which allows for high-power lasers with a wall-plug efficiency of 50%. 40 W cw optical output powers in the near infrared emitted from a 10 mm laser bar are established with excellent lifetimes.