TFT can have a backlight, front/sidelight or use ambient light.
The lightguide, reflector, polarizer and TFT design together determines which type it is:
- Transmissive - Backlight required
- Reflective - Front/sidelight or ambient light required
- Transflective - Backlight, front/side light or ambient light
Whether it is STN (or DSTN, SSTN, CSTN) or TFT, does not limit the above configuration.
Just so we all know.
For current eink designs, Ambient light is needed. Embedded front/side light should possible.
eReaders should have the front/side light embedded and connected to a AA or AAA battery that is easily replaced so that there is the option to have built-in front lighting that is convenient.
Lightwedge is pretty cool and I think was mentioned above.
http://www.lightwedge.com/
http://www.theledlight.com/lightwedge.html
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Originally Posted by kacir
Is it possible to make backlit e-ink display?
Everybody talks about the newest e-ink readers missing a backlight. The question is, can an e-ink dislay have backlight at all?
TFT display can have a backlight. In fact, it is unuseable *without* a backlight.
Black and white lcd display (ala digital watch, or a classical calculator) can have a backlight, because it is transparent. it doesn't really need backlight - in optimal light conditions ;-)
I do not think e-ink display is transparent and I doubt there will be device with a backlit e-ink display in the foreseeable future.
Think about it. The principle of e-ink is: large numbers of very small hollow transparent spheres are filled with white liqiud and black magnetically charged powder suspended in liquid. You can magnetically "pull" the powder to the bottom of sphere - in that case it will apear to be white. Or you can "push" magneticall the powder to the upper part of the sphere, making it look black.
Now close your eyes and imagine a strong light source behind such a display. What do you get? Right. A nice looking uniform gray color.
Take your pick
- do you want an e-ink based bookreader
- or you want a backlit bookreader ?
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