[PLUG-TALK] Light bulbs again

Keith Lofstrom keithl at kl-ic.com
Sun Mar 23 00:27:12 PDT 2008

We argued about light sources a few months back - some folks don't
like the color and warmup time of CFLs, while others don't like the
energy waste of incandescents. 

A bay area company, Luxim, ( www.luxim.com ) is developing a new
kind of electrodeless metal halide lamp ("LIFI") that is daylight
spectrum (95+ color), very efficient (140 lumens/watt), very bright,
and very long lifetime (25000+ hours).  Their first market is
projector bulbs; they are the perfect lamp for DLP projectors. 
Their next markets are street lights and retail lighting. 
Someday they will trickle down to home lighting.  

The bulbs are tiny - a 250W streetlamp bulb is about the size of
a tictac.  The internal temperature is 6000K, about the surface
of the sun, so the brightness is about the same.  Yes, the light
needs to be diffused or they will blind you.

BTW, incandescents run about 15 lumens/watt, CFLs about 60 lm/w,
LEDs and long-bulb fluorescents about 80 lm/w.   Sodium vapor
lamps (streetlights) are about 120 lm/w, concentrated at the
yellow sodium lines.  Astronomers probably won't like them,
since they wash out the entire spectrum rather than a few
filterable lines.

My InFocus LP70 generates a measly 1500 lumens for 120watts, or only
12.5 lm/W .  With a LIFI bulb, I could get 4x the light for the same
power, or the same light with 1/4th the power.  I would not need to
wait for cooldown, and fan noise could be reduced or eliminated.

The LIFI bulb takes about 5 seconds to come to full power;  while
this is great for projectors (UHP bulbs take about 30 seconds),
it will be unacceptable to the instant-on junkies.  

These won't fit in laptops (the external bulb temperature is about
850C) but they would do nicely in folded-optics projection displays.  
The intensity can be controlled digitally over a 5 to 1 range, with
approximately 50msec response.  The bulbs are contactless, and
powered by RF energy (which is why they are long-lasting and dense).  

There is a video (with ads, dammit) on CNET:


So, the "it's gotta be exactly like an incandescent" folks will still
not be pleased.  When electricity reaches 25 cents per KWHr, they
will be incandescently bankrupt .  The rest of us will spend the
5 second warmup time meditating on our cost savings...


Keith Lofstrom          keithl at keithl.com         Voice (503)-520-1993
KLIC --- Keith Lofstrom Integrated Circuits --- "Your Ideas in Silicon"
Design Contracting in Bipolar and CMOS - Analog, Digital, and Scan ICs

More information about the PLUG-talk mailing list