RE: LED's

["Browning David (TVCS)" <BrowningD@tce.com>]

I've seen 18-wheelers with these LED tail/brake lights.  They really throw
you for a loop when they come on because they're so instant.  Bulbs take
forever to turn on and off you know!

dB

> -----Original Message-----
> From:	Wallace White [SMTP:wallace@remdesign.com]
> Sent:	Friday, November 06, 1998 2:51 PM
> To:	Bob Davis
> Cc:	The Quattro List
> Subject:	Re: LED's
> 
> The reason that LED's effective efficiency is so much greater than
> incandescents for tail lights and such is that they emit nearly
> monochromatic light. So if you want a red tail light, you just use a red
> LED, instead of an incandescent light bulb and a red filter that throws
> away most of the light. For the same reason, it's unlikely that we'll
> see LED back-up lights, besides the fact that white LED's are rare and
> expensive right now; LED's are more efficient (visible light per input
> energy) than incandescents only at pretty low power. LED headlights
> would be nowhere close to HID lighting, nor conventional halogen lights,
> if I remember the numbers correctly.
> 
> Regarding the ice issue (which I never would've thought of here in
> CA--good point), maybe you could build a tail light cluster that has
> some IR LED's thrown in to the array, just to use as heat lamps, and
> have your tail light lens be IR blocking. That way you'd be putting heat
> on the lens, which might even do a better (more efficient) job of
> melting ice than having an incandescent bulb that has to heat everything
> up to heat the lens.
> 
> But maybe not!
> 
> - Wallace
>   '87 5kcstq 150k, LED advocate
> 
> Bob Davis wrote:
> > 
> > LED's are cool - they require a lot less power to generate light, and
> they
> > practically never burn out.
> > 
> > One thing to note though - for those of us in living in colder climates.
> > They have such a high light/power ratio because they don't waste energy
> on
> > heat.  They are very cool.
> > 
> > If you think you have troubles keeping your current incandescent lights
> > clear of ice and snow, you'll hate LED's.
> > 
> > Bob Davis
> > bob@segNET.COM
> > 
> > http://www.segNET.COM
> 
> --
> 
>  Wallace White                             wallace@remdesign.com
>  REM Design                                     tel 415.621.3922
>  290 Division St., Suite 401                    fax 415.621.4024
>  San Francisco, CA  94103                      www.remdesign.com