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To: All Mtn Ski who wrote (6195)	7/2/2002 7:29:29 AM
From: John Carragher	Read Replies (1) \| Respond to of 10714

Message 17682386

To: All Mtn Ski who wrote (6195)	7/9/2002 5:20:09 PM
From: All Mtn Ski	Read Replies (1) \| Respond to of 10714

Some CREE info, looks like they can complete with Nichia, no problem <g>: Most Efficient Blue LEDs - 8 to optimistically 12 lumens/watt and maybe soon 14-15 by Cree, 7.5-8 to rarely 10 lumens/watt by Nichia, 9-plus by Lumileds, ~5.5-plus by Toyoda Gosei, and probably Agilent. UPDATE 6/29/2002 - tested a sample LED with a Cree C470-XB290-E1000 die. This LED lamp was an early sample of ETG ETG-5XB470-30. Optical output of the single sample received was approx. 6.5 mW at 20 mA, with a voltage drop of 3.6 volts. Based on prior experience testing LEDs with Cree dice, I expect an improvement of at least 20% and more likely 25-30-plus percent within a few months. In fact, the relevant Cree datasheet claims a typical optical output of 14 mW at 20 mA for this die/chip. This early sample had efficiency very nearly usual for Nichia, and the likely prospect is that efficiency will soon exceed that of Nichia. Also consider that ETG seems hellbent on significantly beating Nichia prices. Also consider that Cree, unlike Nichia, produces reliably available quantities of LED dice with the 460 nm deeper blue wavelength in addition to the usual 470 nm wavelength. 460 is better than 470 for use in LED video displays - 460 nm has greater "blue color impact" useful in an RGB device than 470 nm despite 460 nm having lower photometric performance than 470 nm. Photometric output of an RGB device is normally almost entirely from green and red rather than blue, so blue LEDs with greater "blue impact" and purer shade of blue can easily be superior even if photometric specifications are inferior. One thing to look for is photometric output after multiplying by the ratio of Z to Y CIE chromaticity figures. This seems to be a running talley if you go to the link, but the date of this section is 6/29/2002, and seems very positive for CREE: misty.com Here is his LED link page, anyone want an LED education? <g>: misty.com A-M-S