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Directional optical filter

  • US 4,621,898 A
  • Filed: 03/17/1983
  • Issued: 11/11/1986
  • Est. Priority Date: 03/17/1983
  • Status: Expired due to Fees
First Claim
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1. Filter for selectively admitting radiant energy to pass therethrough including at least one radiant energy transmitting media having first and second sides, and a surface of the media on the first side, wherein an image on one side of the media can be viewed from the other side, characterized by:

  • said surface being interrupted by a plurality of light-absorbing grooves, the plurality of grooves extending from said surface, extending less than completely through the media and arranged in a pattern, the grooves having a characteristic of absorbing said radiant energy impinging thereon from within the media, such that radiant energy passing said surface from a pre-determined angle from normal to said surface is substantially absorbed and radiant energy passing said surface from less than said pre-determined angle and not impinging upon the grooves is transmitted in accordance with radiant energy transmitting characteristics of said media for that energy.

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