Uncooled background limited detector and method

• US 6,166,381 A
• Filed: 04/06/1998
• Issued: 12/26/2000
• Est. Priority Date: 07/19/1996
• Status: Expired due to Term

• Current Assignee: Harris Corporation (L3Harris Technologies, Inc.)
• Original Assignee: AIL Systems, Inc. (ITT, Inc.)
• Inventors: Knadle, Richard T., Augeri, Richard C., Lange, Ronald A.
• Primary Examiner(s): Ham, Seungsook
• Assistant Examiner(s): HANIG, RICHARD E
• Application Number:
  US09/055,773
• Time in Patent Office: 995 Days
• Field of Search: 250/332, 250/330, 250/338.1, 250/339.01, 374/205
• US Class Current: 250/332
• CPC Class Codes: G01J 1/46 using a capacitor
• CPC Class Codes: G01J 5/20 using resistors, thermistors or semiconductors sensitive to radiation, e.g. photoconductive devices
• CPC Class Codes: G01J 5/24 Use of specially adapted circuits, e.g. bridge circuits
• CPC Class Codes: G01J 5/34 using capacitors, e.g. pyroelectric capacitors
• CPC Class Codes: G01J 5/38 using extension or expansion of solids or fluids
• CPC Class Codes: H04N 5/33 Transforming infrared radiation cameras or camera modules for generating image signals from infrared radiation H04N23/20; circuitry of SSIS for transforming infrared radiation into image signals H04N25/20

Abstract

A detector for detecting radiant energy includes at least one detecting element and a detector readout element. The at least one detecting element substantially absorbs the radiant energy and exhibits a structural change in response thereto. The detector readout element, positioned in non-contacting proximity to the at least one detecting element, is responsive to the structural change of the at least one detecting element. The non-contacting detector readout element provides an indication signal corresponding to the structural change, whereby the corresponding indication signal is representative of the radiant energy detected by the at least one detecting element.

Claims

1. A system for imaging radiant energy associated with a thermal scene, the system comprising:

a focal plane array, the focal plane array including a plurality of uncooled background limited detectors which are thermally and electrically isolated;

an imaging lens, the imaging lens being positioned between the focal plane array and the thermal scene, the imaging lens passing the radiant energy associated with the thermal scene to the focal plane array, each one of the plurality of detectors of the focal plane array substantially absorbing the radiant energy passed by the imaging lens and incidentally introduced to the focal plane array, each one of the plurality of detectors structurally changing in response thereto;

a beam splitter, the beam splitter being positioned in relation to the focal plane array whereby a plurality of distances respectively exist between the beam splitter and the plurality of detectors;

a mirror, the mirror being positioned at a distance d from the beam splitter and perpendicular in relation to the focal plane array;

a viewing lens, the viewing lens being positioned opposite to the mirror with the beam splitter being positioned therebetween;

a light emitting source, the light emitting source being positioned opposite to the focal plane array with the beam splitter being positioned therebetween, the light emitting source emitting a light beam;

a focusing lens, the focusing lens being positioned between the light emitting source and the beam splitter;

the beam splitter splitting the light beam, emitted by the light emitting source and passing through the focusing lens, into a transmitted beam portion and a reflected beam portion;

the transmitted beam portion being transmitted through the beam splitter and striking the plurality of detectors, the plurality of detectors respectively reflecting a plurality of imaging beams back toward the beam splitter, the beam splitter then substantially reflecting the plurality of imaging beams toward the viewing lens;

the reflected beam portion being reflected by the beam splitter and striking the mirror, the reflected beam portion reflecting back toward the beam splitter, the beam splitter then substantially transmitting the reflected beam portion toward the viewing lens; and

the reflected beam portion and the plurality of imaging beams passing through the viewing lens and respectively exhibiting a plurality of interference patterns, the plurality of interference patterns forming a visual representation of the radiant energy associated with the thermal scene, the plurality of interference patterns changing in response to a respective change in difference between the plurality of distances and the distance d, each one of the plurality of distances respectively changing, thereby causing a change in difference with respect to the distance d, as each one of the plurality of detectors experiences a structural change in response to absorbing the radiant energy associated with the thermal scene.

2. A system as defined in claim 1, further comprising a charge coupled device, the charge coupled device being positioned opposite the mirror with the viewing lens positioned therebetween, the charge coupled device being responsive to the plurality of interference patterns.