Papers point to LED lights in the lounge
17 Jun 2002
The market for compound semiconductors is set to grow to USD 9 billion in 2002, from the 1997 figure of USD 5.7 billion, with LEDs accounting for 33% of this and lasers claiming 28%. A host of papers at Photonics West charted some of the responses to the fast growing market of LEDs.
Nichia has made white LEDs with a luminosity of 15 lumens per watt. The company aims to achieve 70 lumens per watt, which will improve on the 68 currently offered by fluorescent lighting. HP is also working on high brightness LEDs and the company announced white LEDs which give 40 lumens per watt at an efficiency of up to 58%. HP predicts that we will soon see white LEDs in domestic lighting.The joint venture optoelectronics company of Agilent and Phillips has made a yellow/amber AlGaInP LED with a luminosity of 102 lumens per watt. The device, which needs a current of 100 milliamps to emit light, is called a TIPLED, or truncated inverted pyramid light emitting diode.Toyoda Gosei, a subsidiary of Toyota, has created a new design of blue and green LEDs which should be commercially available in about five months time. The green LED has a brightness of 14 candela and an efficiency of 17% while the 6-candela blue has an efficiency of 20%. The initial price will be about 80 or 90 US cents per LED, when bought in bulk, but this should reduce to about 60 or 70 US cents, like other LEDs of these colours, within a few months.Researchers at the University of Ulm, in Germany have made a 45% quantum efficiency laterally tapered truncated LED. This LED, which has an efficiency of 26% without its packaging, has a power density of 10 watts per square centimetre and gives a power of 4.6 milliwatts at 10 milliamps.SH
