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Subject: Re: luxeon star leds
Date: Thu, 28 Nov 2002 18:59:02 -0800
Organization: SCN Research of Tigard, Oregon, USA.
References: <3DDD9A57.58900EFB@RobertsResearchInc.com> <firstname.lastname@example.org> <3DDDB646.96D0D9D2@RobertsResearchInc.com> <3DDE7264.CD48F4F8@RobertsResearchInc.com> <email@example.com> <3DDEB081.884EC92A@RobertsResearchInc.com> <3DE03D65.932BF9BF@RobertsResearchInc.com> <3DE15871.EF8FF9EA@RobertsResearchInc.com> <3DE224D3.81EFBA3C@RobertsResearchInc.com> <3DE4C4C1.50072B92@RobertsResearchInc.com> <3DE62B7B.53D088E8@RobertsResearchInc.com>
NNTP-Posting-Date: Fri, 29 Nov 2002 02:59:13 +0000 (UTC)
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This thread is kinda scary, folks, you really need to heatsink these
devices very well.
At the seminar, LumiLeds (Luxeon), mentioned there have been
many cases where engineers have claimed they were keeping the
devices cool. Analysis of the failed devices, then taking a look
at the devices in their application showed they were not being kept
cool enough, causing subsequent early failures of the devices.
"Victor Roberts" wrote in message
> Bob Wilson wrote:
> > >Even though I also disagreed with the original poster that
> > >the small aluminum-core PCB would stabilize at 60C, I have
> > >found the reference he may have used. There is a small data
> > >sheet with the Luxeon logo inside plastic bag with the
> > >Luxeon Star/O LED sample I received at Light Fair 2001. It
> > >says "For sustained operation please ensure that the unit is
> > >properly mounted to a secondary heatsink. The back surface
> > >of MCPCB will stabilize at 60C without any additional
> > >heatsinking."
> > Well, I wouldn't trust it too much. We found that a single Luxeon
> > the ~1" square metal core PCB got significantly hotter than 60, and got
> > there pretty fast.
> > The Luxeon Line product (12 LEDs mounted on a long metal core board) did
> > little better, but still at 60C the light output has already dropped
> > somewhat, and the life will be significantly reduced.
> I was simply quoting the information provided on the
> datasheet that Lumileds placed inside the plastic bag with
> the Luxeon LED. I have no independent confirmation of their
> claim. A agree that both light output and life will be
> reduced by operating without a heat sink. This was discussed
> in another part of this thread.
> Vic Roberts
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