LED light Brightness
(loosly adapted from a press release)
OSRAM has announced that it has achieved a new record for white light LEDs of 155 lumen in brightness, and 136 lm/W in efficacy at an anode current of 350mA.
Prototype LEDs with 1 square millimeter chips were used. The light was a bluish white with a colour temperature of 5000 K.
Among the elements that led to LED success was an extremely efficient light converter and a special high-performance package.
At a current of 1.4 Amps these LEDs can produce up to 500 lm of white light. This means that the LEDs can be used not only for general lighting and car headlights but also as light sources in projector systems.
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For the technically more advanced reader here is a very interesting extract from Wikipedia on the history of LEDs.
LED Efficiency and operational parameters (extract from Wikipedia) http://en.wikipedia.org/wiki/LED
Most typical LEDs are designed to operate with no more than 30–60 milliwatts (mW) of electrical power. Around 1999, Philips Lumileds introduced power LEDs capable of continuous use at one watt (W). These LEDs used much larger semiconductor die sizes to handle the large power inputs. Also, the semiconductor dies were mounted onto metal slugs to allow for heat removal from the LED die.
One of the key advantages of LED-based lighting is its high efficiency, as measured by its light output per unit power input. White LEDs quickly matched and overtook the efficiency of standard incandescent lighting systems. In 2002, Lumileds made five-watt LEDs available with a luminous efficacy of 18–22 lumens per watt (lm/W). For comparison, a conventional 60–100 W incandescent lightbulb produces around 15 lm/W, and standard fluorescent lights produce up to 100 lm/W.
In September 2003, a new type of blue LED was demonstrated by the company Cree, Inc. to provide 24 mW at 20 milliamperes (mA). This produced a commercially packaged white light giving 65 lm/W at 20 mA, becoming the brightest white LED commercially available at the time, and more than four times as efficient as standard incandescents. In 2006 they demonstrated a prototype with a record white LED luminous efficacy of 131 lm/W at 20 mA. Also, Seoul Semiconductor has plans for 135 lm/W by 2007 and 145 lm/W by 2008, which would be approaching an order of magnitude improvement over standard incandescents and better even than standard fluorescents. Nichia Corporation has developed a white light LED with luminous efficacy of 150 lm/W at a forward current of 20 mA. In May 2008, 130lm/W is available from Chinese LED manufacturers.
It should be noted that high-power (≥ 1 W) LEDs are necessary for practical general lighting applications. Typical operating currents for these devices begin at 350 mA. The highest efficiency high-power white LED is claimed by Philips Lumileds Lighting Co. with a luminous efficacy of 115 lm/W (350 mA).