Thermal imager
First Claim
Patent Images
1. A thermal imager including a detector mounted on a cooled substrate, an optical system and a field stop which is positioned and is of a suitable size to limit narcissus rays to those which emanate from the detector only.
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Abstract
A thermal imager employs an intermediate field stop (8) which is preferably placed at an intermediate image plane (P) in front of a cryogenically cooled detector (1) mounted on a substrate (2). Radiation gathered by a telescope is directed onto the detector through an aperture (9) in the field stop. The field stop limits the rays which are emitted by the detector and substrate and which are subsequently retro-reflected back to the detector (called narcissus rays).
19 Citations
5 Claims
- 1. A thermal imager including a detector mounted on a cooled substrate, an optical system and a field stop which is positioned and is of a suitable size to limit narcissus rays to those which emanate from the detector only.
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4. A thermal imager, comprising:
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a detector mounted on a cooled substrate; means for forming an intermediate image plane in front of the detector; a field stop in the intermediate image plane, the field stop having an aperture; and at least one lens between the field stop and the detector and substrate, wherein the field stop limits narcissus rays to those which emanate from the detector only, the aperture being dimensioned to block radiation emanating from the substrate. - View Dependent Claims (5)
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Specification