Re: Cree 40-60lm/W LEDs 'in the wild'?

On Thu, 30 Jun 2005 01:38:12 +0200, "Adam Wilanowski"
<wilan@xxxxxxxxxx> wrote:


>You are right, but our customer can do chocie if they want the XLamps from
>low lumen bins (23,5 - 39,8lm) or from high lumen bins (39,8 - 67,2lm). This
>works also for other colour XLamp LED's. So, there is always an alternative.

Thanks for the info to clear up my questions. The issue that concerns
me is the huge spread in LED performance. Even the "high lumen" bin
has a rather low minimum lumen output. The manufacturers use a mean or
median number in their advertising, yet the customer has no guarantee
that they will receive a device as good as the advertised number. If
the higher numbers are real and can be reproduced, why do the
manufacturers not use much smaller bins so that customers have a
better idea of the performance they will get from the LEDs they
purchase?

If LEDs were sold as lamps in the US I strongly suspect the Federal
Trade Commission would force manufacturers to put either the lowest
number on the box and in their advertising, or put the full range on
the box and in their advertising.

This opinion is based on a similar issue involving the difference
between base-up and base-down performance of CFLs. In that case the
FTC was going to force the lamp manufacturers to use either both
numbers or only the lower number instead of only the higher number as
they had been doing. The issue was resolved by replacing liquid
mercury with mercury amalgams that significantly reduced the
difference between base-up and base-down performance.

--
Vic Roberts
http://www.RobertsResearchInc.com
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