Quote:
Originally Posted by astra
No visible backlight. But how does it work then if it does not have a light?
|
What do you mean? The LCD screen polarizes a portion of the screen so that the diode becomes opaque. From Wikipedia:
Quote:
|
When a voltage is applied across the electrodes, a torque acts to align the liquid crystal molecules parallel to the electric field, distorting the helical structure (this is resisted by elastic forces since the molecules are constrained at the surfaces). This reduces the rotation of the polarization of the incident light, and the device appears grey. If the applied voltage is large enough, the liquid crystal molecules in the center of the layer are almost completely untwisted and the polarization of the incident light is not rotated as it passes through the liquid crystal layer. This light will then be mainly polarized perpendicular to the second filter, and thus be blocked and the pixel will appear black.
|
The LCD itself does not provide the light in any way. Perhaps you are confusing it with an LED which causes the diode to glow. The light of the Jetbook screen that allows you to see the crystals as black or not comes from ambient light reflected of the screen. This is in contrast to an LCD monitor for example which has a layer under the TFT substrate which glows.
An eInk works similar but the method to make the pixes opaque or transparent is done differently and also it doesn't require continous power to maintain that state as does an LCD.
BOb