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Backlight assembly for improved illumination employing tapered optical elements

  • US 5,598,281 A
  • Filed: 11/19/1993
  • Issued: 01/28/1997
  • Est. Priority Date: 11/19/1993
  • Status: Expired due to Term
First Claim
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1. A backlight assembly for use in an electo-optical display, said display having a modulating means capable of providing an image to a remotely positioned observer, and said backlight assembly comprising:

  • (a) a light generating means;

    (b) an aperturing means operatively disposed in close proximity between said light generating means and said modulating means;

    (c) a first collimating means disposed between said aperturing means and said modulating means, said first collimating means having a planar light input surface in close proximity to said aperture means and a planar light output surface distal from and parallel to said light input surface and larger in surface area than said light input surface, wherein said light rays transmit through said first collimating means via total internal reflection and exit from said light output surface in a substantially collimated pattern; and

    (d) a second collimating means disposed between said first collimating means and said modulating means and having a light input surface that accepts said substantially collimated light rays from said first collimating means and transmits the light rays via refraction and directs said light rays towards said modulating means in a substantially more collimated pattern.

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