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#201119 - 28/01/2004 23:09 White LEDS..
foxtrot_xray addict Registered: 03/03/2002 Posts: 687 Loc: Atlanta, Georgia	Rant. Well, semi-rant. How come they're not really white, but a really, really light blue? Are there LEDs that ARE white? Like, a WARMER white? I keep hoping a warmer white comes out, but nooo.. just brighter blue-whites. Hmph. Me. _________________________ Mike 'Fox' Morrey 128BPM@124MPH. Love it! 2002 BRG Mini Cooper
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#201120 - 29/01/2004 03:20 Re: White LEDS.. [Re: foxtrot_xray]
Roger carpal tunnel Registered: 18/01/2000 Posts: 5683 Loc: London, UK	IIRC, they're not really white. They're generally a blue/UV LED with a flourescent coating. Hence the blue tinge. _________________________ -- roger
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#201121 - 29/01/2004 09:50 Re: White LEDS.. [Re: Roger]
Skunk Master Boot Logo(er) Registered: 26/08/2003 Posts: 525 Loc: California	I heard white is the hardest color to produce in LEDs. Is this true? _________________________ aka: [color:"blue"]Boot Logo Master[/color] PayPal Contributions for Custom Boot Logos are gladly accepted. <img src="/ubbthreads/images/graemlins/smile.gif" alt="" /> itirado[@]adobe[.]com
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#201122 - 29/01/2004 12:11 Re: White LEDS.. [Re: Skunk]
mtempsch pooh-bah Registered: 02/06/2000 Posts: 1996 Loc: Gothenburg, Sweden	Yup - because white is a mix of all colors, while a LED typically emits light heavily centered around a specific color/wavelength... I've seen pretty decent white (not high-intensity though) from RGB LEDs (LEDs with 3 (or more) diodes internally, one each red, green, blue), but it required some finetuning of the voltages to each element... One can also do pretty neat effects with independent slowly changing voltage on each of the inputs... /Michael _________________________ /Michael
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#201123 - 29/01/2004 12:27 Re: White LEDS.. [Re: mtempsch]
g_attrill old hand Registered: 14/04/2002 Posts: 1172 Loc: Hants, UK	One can also do pretty neat effects with independent slowly changing voltage on each of the inputs... For christmas my mum got a frosted 3D-star decoration which cycled through lots of colours - I inspected it and it looked like it was a single RGB LED doing what you describe - looked very nice. Gareth
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#201124 - 29/01/2004 12:37 Re: White LEDS.. [Re: mtempsch]
peter carpal tunnel Registered: 13/07/2000 Posts: 4180 Loc: Cambridge, England	Yup - because white is a mix of all colors, while a LED typically emits light heavily centered around a specific color/wavelength... As a result of one of those pub conversations that started with "Show me something macroscopic that demonstrates that quantum mechanics is real", it turns out that you can predict the colour of an LED from its voltage drop, or vice versa, with complete accuracy by converting eV to joules for the incoming electrons and using E=hf for outgoing photons, on the quantum-mechanical basis that each electron's energy is released in exactly one photon. Peter
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#201125 - 29/01/2004 13:24 Re: White LEDS.. [Re: foxtrot_xray]
siberia37 old hand Registered: 09/01/2002 Posts: 702 Loc: Tacoma,WA	I've seen some pretty good and very bright white leds that my father in law has. He works for a sign company and they use them to replace white neon in signs- so they are bright and don't have a noticeable color tint. They are not cheap though- if you need more info on where he gets them let me know.
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#201126 - 29/01/2004 14:44 Re: White LEDS.. [Re: siberia37]
maczrool pooh-bah Registered: 13/01/2002 Posts: 1649 Loc: Louisiana, USA	Luxeon? Stu _________________________ If you want it to break, buy Sony!
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#201127 - 29/01/2004 15:35 Re: White LEDS.. [Re: peter]
foxtrot_xray addict Registered: 03/03/2002 Posts: 687 Loc: Atlanta, Georgia	As a result of one of those pub conversations that started with... I dunno what pub YOU go to, but they sound pretty up-tight. Me. _________________________ Mike 'Fox' Morrey 128BPM@124MPH. Love it! 2002 BRG Mini Cooper
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#201128 - 29/01/2004 15:38 Re: White LEDS.. [Re: maczrool]
foxtrot_xray addict Registered: 03/03/2002 Posts: 687 Loc: Atlanta, Georgia	Interesting! Thanks! Now I need them to give light out in ALL directions, and then.. THEN! I'll have PERMANENT REPLACEMENTS for all the little bulbs in my Pinball Game! Muahaha! ahem Sorry. Me. _________________________ Mike 'Fox' Morrey 128BPM@124MPH. Love it! 2002 BRG Mini Cooper
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#201129 - 29/01/2004 16:27 Re: White LEDS.. [Re: foxtrot_xray]
Roger carpal tunnel Registered: 18/01/2000 Posts: 5683 Loc: London, UK	I dunno what pub YOU go to IIRC, that conversation was started in the Live and Let Live in Cambridge, just off Mill Road. We did the working out on the whiteboard in the office the following morning -- 'cos none of us could remember any of the constants. _________________________ -- roger
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#201130 - 09/03/2004 06:40 Re: White LEDS.. [Re: foxtrot_xray]
Mach old hand Registered: 15/07/2002 Posts: 828 Loc: Texas, USA	I just received this in my inbox. Thought you might be interested. We proudly present a series of brand new white LEDs WHITE LEDs based on ZnSe technology. These ZnSe LEDs emit white light without blue LED conversion YAG! how it works: ZnSe LED chips emitting two colors at the same time, one peak at 484 nm (blue) and one peak at 605 nm (yellow) - mixing these two wavelengths inside the epoxy housing "generates" white light: http://www.roithner-laser.com/ http://www.roithner-laser.com/All_Datasheets/Pricelists/
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#201131 - 09/03/2004 08:20 Re: White LEDS.. [Re: Mach]
foxtrot_xray addict Registered: 03/03/2002 Posts: 687 Loc: Atlanta, Georgia	Hmm.. Interesting. I'm mwilling to try that.. Thanks! Mike. _________________________ Mike 'Fox' Morrey 128BPM@124MPH. Love it! 2002 BRG Mini Cooper
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