Silicon Investor (SI) -- The First Internet Community

STOCKTALK

We've detected that you're using an ad content blocking browser plug-in or feature. Ads provide a critical source of revenue to the continued operation of Silicon Investor. We ask that you disable ad blocking while on Silicon Investor in the best interests of our community. If you are not using an ad blocker but are still receiving this message, make sure your browser's tracking protection is set to the 'standard' level.

Technology Stocks : White light from LED -- Ignore unavailable to you. Want to Upgrade?

To: semi_infinite who wrote (186)	2/25/2000 5:08:00 PM
From: John Finley	Respond to of 565

SiC biggest advantage is form factor and not brightness Sounds reasonable to me. From what I understand SiC or sapphire is just the substrate for the junction materials (doped GaN). SiC is nice because it can be "super" doped into a conductor so that one electrical connection is on the backside away from the light-emitting part (form factor). SiC also has really good thermal conductivity although I don't know if heat is a problem. I'm not sure how the brightness varies with lattice mismatch so I don't know how people are tweaking brightness, but I would guess it's in the junction (GaN) part. BTW, I don't believe SiC is less expensive than sapphire. Last sapphire I bought was <$100 2" wafer. As an aside, anyone with an interest in "white LED" plays ought to check out: This agreement will bring to SLI (formerly Chicago Miniature Lamp) the same depth of LED technology, including "white LEDs", as any of the large industry players. SLI, Inc. is now uniquely positioned in the marketplace, with its global infrastructure of value added miniature lighting manufacturing operations to serve the needs of the major OEMs with full service design and production of the complete lighting system. sli-lighting.com sli-lighting.com BTW, SLI has a PE ~11 JF

To: semi_infinite who wrote (186)	2/25/2000 8:41:00 PM
From: unclewest	Read Replies (1) \| Respond to of 565

thank you, that helped me a lot

To: semi_infinite who wrote (186)	2/25/2000 11:42:00 PM
From: mauser96	Read Replies (1) \| Respond to of 565

I too have serious doubts about the brightness of Cree white LED. As far as I can determine in applications where brightness is of primary importance (flashlights) the LED are almost entirely Nichia . I have seen one with a noticeable lower white light output but don't know who made it. There are various ways to measure brightness, most not originally designed for LED, so this does allow a little wiggle room. Also to most eyes a more concentrated beam looks brighter than a diffuse one. Nevertheless, I consider Cree management remarks on this subject may be disingenuous, especially since the company has refused to send or sell me samples I can test. The brightness is mainly due to the GaN layer, so maybe Cree has put less work into this than the SiC substrate. The brightness gap probably has not been closed.