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Image projection display screen employing polymer dispersed liquid crystal layer and electrochromic layer

  • US 5,416,617 A
  • Filed: 07/16/1993
  • Issued: 05/16/1995
  • Est. Priority Date: 11/22/1991
  • Status: Expired due to Fees
First Claim
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1. A diffusing display screen comprising a combination ofa cell (C1) which comprises a polymer film (P) having an optical index np, in which are dispersed microballs which are oblong in shape, the larger axis thereof being laid out in parallel to the plane of the film, wherein said microballs contain oblong and birefringent liquid crystal molecules of extraordinary index ne such that ne is equal to np, anda cell (C2) which comprises a layer of electrochromic material (Ec), and transparent electrodes (F2) which allow a voltage to be applied to said cell (C2) so as to switch said cell (C2) from a transparent state to an absorbing and reflecting state, wherein both of said cells (C1) and (C2) being fixed onto a surface,wherein said diffusing display screen is for use with a standard image projector and operates in a reflection mode which allows reflection of images whose size may be variable.

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