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Subject: Re: Broken LCD :(
From: Chris Holt (amiga2k_at_cox.net)
Date: 2004-03-21


On Sat, 20 Mar 2004 20:34:09 -0500, David Litchman wrote:
> To the best of my understanding, using inverse display would make no
> difference in power consumption. In an LCD, there are tiny little
> crystals which are suspended in liquid (hence the name). If a
> particular cell (or pixel, if you prefer) is on, then a charge is
> passed through it which aligns the crystals in such a way as to allow
> light through. If it's off, then the charge is used to align the
> crystals so that light will not pass through. So regardless of whether
> or not the pixel is illuminated the same amount of power is used. At
> least, that's how I understand it. If anyone knows better please feel
> free to correct me.

Put simply an LCD display consists of two pieces of polarized glass with
the polarization 90 degrees out from each other. The crystals in between
are oriented in a twisted pattern in their natural state. The light
passing through the first polarized layer is twisted 90 degrees and is
allowed to pass through the second polarized layer (a transparent pixel)
When you pass current through these crystals, they line up and make the
pixel opaque. So... When a pixel on an LCD display is transparent, it is
off, no current applied. Simple logic applies here, since when the unit
is off, the entire screen is transparent, because the crystals are "doing
the twist". :)

For a more detailed explanation than that:
http://computer.howstuffworks.com/lcd1.htm
(probably more than most people want to know about LCDs!)

Chris

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