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Low-observability, wide-field-of-view, situation awareness viewing device

  • US 6,693,749 B2
  • Filed: 01/31/2001
  • Issued: 02/17/2004
  • Est. Priority Date: 01/31/2001
  • Status: Expired due to Term
First Claim
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1. A situation awareness viewing device, comprising:

  • a polarizing beam splitter comprising a cube of a material transparent to light and having an index of refraction greater than 1, and a wire grid polarizer lying within the cube on a cube-diagonal plane extending between two diagonally opposed edges of the cube, the polarizing beam splitter having a first optical axis extending from a first face of the cube toward an opposing second face of the cube and lying at an angle of 45 degrees to the cube-diagonal plane, and a second optical axis extending from a third face of the cube toward an opposing fourth face of the cube and lying at an angle of 45 degrees to the cube-diagonal plane, the second optical axis being perpendicular to the first optical axis;

    an external polarizer external to the cube on the first optical axis and disposed to intercept light incident upon the first face along the first optical axis;

    an unpolarized image source external to the cube and disposed to send a display image incident upon the third face along the second optical axis;

    a quarter-wave plate external to the cube and disposed to intercept a beam of light traveling along the second optical axis and passing out of the cube through the fourth face; and

    a mirror external to the cube and disposed to reflect light passing through the quarter-wave plate back through the quarter-wave plate and to the fourth face.

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