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Illumination device having a light guide with leaky side surfaces

  • US 10,473,847 B2
  • Filed: 07/18/2014
  • Issued: 11/12/2019
  • Est. Priority Date: 07/18/2013
  • Status: Active Grant
First Claim
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1. An illumination device comprising:

  • one or more light-emitting elements (LEEs) arranged to provide light;

    a light guide comprisinga receiving end and an opposing end, the receiving end arranged to receive the light provided by the LEEs, anda pair of opposing side surfaces extending along a length of the light guide between the receiving end and the opposing end, the light guide configured toguide the received light in a forward direction, along the length of the light guide toward the opposing end of the light guide, andtransmit a first portion of the guided light into ambient environment through one or more of the opposing side surfaces as sideways leaked light; and

    an optical extractor located at the opposing end and configured to output into the ambient environment a remaining portion of the guided light—

    that reaches the opposing end—

    as output light in backward directions,wherein the light guide is tapered such thata receiving aperture at the receiving end of the light guide is larger than an output aperture at the opposing end,an angle of incidence of guided light incident on the opposing side surfaces exceeds a critical angle beyond a predetermined distance from the receiving end, andsome of the light guided beyond the predetermined distance transmits into the ambient environment through the opposing side surfaces as the sideways leaked light.

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