Laptop CCFL as emergency area-light?

Nubo

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Dec 23, 2004
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I've heard that the CCFL used in laptops are exceedingly efficient. I do notice that a fully-bright screen displaying a white page, for example, can light up an area decently.

Hardly worth it though, since your power is quickly eaten by running the computer.

But, does anyone know how much these bulbs consume, just on their own? I'm wondering how long you could have light if the power was exclusively used to light the CCFL/screen, with say, a 70 watt-hour battery?

Might it be useful enough for manufacturers to consider adding that functionality for the benefit of consumers? Not everyone stocks emergency lighting supplies but laptops are becoming ubiquitous.

Worthwhile at least as a mod?
 

billw

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Lots of data here:
http://www.jkllamps.com/index.cfm?action=fam&tid=2&fID=31

How efficient they are is highly dependent on the inverter being used,
of course, and a lot of attention has been paid to making the inverters
in laptops more efficient. The backlight is still one of the power-hungry
pieces of the laptop, though, usually consuming 5-10W, I think...

There are commericial battery operated lamps; my impression is that
they generally contain cheaper and less efficient inverters; though I
don't know just how much less efficient.

One of the nice things about LEDs is the comparitively simple electronics
needed to drive them...
 

SemiMan

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Jan 13, 2005
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Think 40-70 Lumens/watt (depending on the tube, but also on the length). The longer tubes tend to be more efficient. 3-8 watts again depending on the length. Many options for inverters from Microsemi, TDK, ERG (sp?), etc. They are generally quite efficient these days. Microsemi has full dimming.

Your laptop only transmits about 10% or less of the light the bulb actually generates so that gives you an idea of just how much light there could be.

Semiman
 

DCFluX

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Jan 4, 2006
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You can buy off the shelf CCFL tubes packaged with protective housing and an inverter that are +12 volt ready in a number of places for less then $10.These are usually avalible in every color including White and UV.

Some people have been known to make inverters that will run on 3 VDC, but not many and they are limited by the length of the tube.
 

IMSabbel

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Dec 4, 2004
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921
Dont forget that even when on white, the lcd has HUGE losses (2/3 in the colour filters and 50% of the rest gets stuck in the polarizers).
So the enourmous efficiency of the backlight and the nice, big, near-lambertian illumination area make them that decent as illumination (plus the fact that they use the best of the best in battery technology doesnt hurt).
 
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