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Stage lighting methods and apparatus

  • US 8,282,245 B2
  • Filed: 04/30/2007
  • Issued: 10/09/2012
  • Est. Priority Date: 11/19/2004
  • Status: Active Grant
First Claim
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1. A projection optical system, comprising:

  • a light source;

    a projection gate;

    a projection lens configured to project an image of the projection gate, wherein the projection gate is located between the light source and the projection lens;

    a filter apparatus adapted to position a selected area of a variable density filter in a portion of light from the light source illuminating the projection gate, wherein the variable density filter has a pattern; and

    a relay lens group located between the filter apparatus and the projection gate, wherein light reaching the relay lens group is not redirected between the filter apparatus and the relay lens group and the relay lens group is configured to prevent the projection lens from projecting an image of the pattern of the variable density filter.

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