[ltp] Re: fan problem on R51

[André Wyrwa]

> In the side of the LCD panel there is a flourescent light tube. 
> Sometimes there is one on both sides.

Its always two or else the display would not be homogenically enlighted.

> The backlight seems to be the primary consumer of energy in the
> display.    I'm not sure how much electricity is consumed by the LC
> control circuitry or whether a largely black image will consume less
> power than a mostly white display.

Depends on how the display is built. There are displays built in a way
that the crystals let light pass when the according transistor is
activated, and such that let it pass when the transistor is off. Don't
know which kind is in Thinkpads. Anyway, since the transistors actively
consume power it is at least in theory a difference if the backlight is
switched of on a completely white image or completely black image. But i
guess the power consumtion of these transistors is practically nothing.

> LED's and plasma displays work on completely different properties. I
> think plasmas draw several times as much power as LCD's and LED's are
> very bright and efficient but not very small.

LEDs can be very small as well. NEC and others are trying to develop LED
driven flat panel displays. The trouble with this is AFAIK that they
don't manage to get a homogenic illumination so far.

André.