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% lost to liquid crystal filters

  1. Sep 6, 2008 #1
    I've got a random question. To my knowledge a liquid crystal filter bends incoming light coming in from various angles towards one particular angle as light leaves the filter. Does anybody know the % loss of light caused by this action?
  2. jcsd
  3. Sep 6, 2008 #2


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    Homework Helper

    Liquid crystal filters are to polarize light.
    Try looking with that keyword.
  4. Sep 6, 2008 #3


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    Staff: Mentor

    As NoTime says, LCDs work because of the ability of the liquid crystal layer to either rotate the plane of the incoming light polarization, or not (depending on whether there is a voltage applied across the LC layer). So to turn LC pixels on and off, a voltage is applied across the pixel. Different LCD designs either turn on the pixel or turn it off when the voltage is applied, but that's irrelvant to your question.

    But for the LC layer to cause the pixel to be on or off based on whether the polarization is rotated or not, the incoming light going through the LC layer of the pixel must be polarized first. That is the job of the front polarizer in the LCD -- to present only appropiriately-polarized light to the LC layer of the cell. If you search on wikipedia.org or howstuffworks.com about liquid crystal displays, they should have some good diagrams and explanations.
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