Background Limited Focal Plane Array Assembly

• US 20130206990A1
• Filed: 08/20/2012
• Published: 08/15/2013
• Est. Priority Date: 08/22/2011
• Status: Abandoned Application

• Current Assignee: PFG Ip, LLC
• Original Assignee: ISC8 Incorporated
• Inventors: Hsu, Ying, Azzazy, Medhat, Tea, Nim
• Application Number:
  US13/589,231
• Publication Number:
  US 20130206990A1
• Time in Patent Office: Days
• US Class Current: 250/338.4
• CPC Class Codes: G01J 5/023 Particular leg structure or construction or shape; Nanotubes
• CPC Class Codes: G01J 5/046 Materials; Selection of thermal materials
• CPC Class Codes: G01J 5/0806 Focusing or collimating elements, e.g. lenses or concave mirrors
• CPC Class Codes: G01J 5/12 using thermoelectric elements, e.g. thermocouples

Abstract

The thermoelectric detector comprises an infrared absorber pixel structure supported by two electrically connected beams made of a thermoelectric material. One end of the thermoelectric beam connects to the infrared absorber pixel structure; the other end connects to the substrate. The detector comprises a microlens for collecting and focusing infrared radiation on the detector. Infrared radiation is incident on the infrared absorber pixel structure results in a temperature gradient along the length of the thermoelectric legs, and generating an electrical voltage proportional to the gradient. A low noise SIGe BiCMOS readout integrated circuit is coupled to the detector to provide a background limited detector having improved detectivity.

Claims

1. A detector assembly comprising:

a thermoelectric detector comprising an infrared absorber pixel structure comprising a pixel surface area,

the infrared absorber pixel structure coupled to at least one thermoelectric structure at a hot junction,

a microlens element configured to collect and focus infrared energy of a predetermined spectrum upon the pixel surface area, and,

a read out integrated circuit.

2. The device of claim 1 wherein the read out integrated circuit comprises a SiGe BiCMOS readout integrated circuit fabricated in a set of SiGe BiCMOS semiconductor processing steps coupled to the at least one thermoelectric structure at a cold junction.

3. The device of claim 1 wherein the at least one thermoelectric structure comprises at least one of bismuth-telluride, antimony-telluride, lead telluride, polysilicon, germanium, skutterudite, a nano-composite material, and a super-lattice structure.

4. The device of claim 1 wherein the substrate comprises a reflector.

5. The device of claim 1 wherein the first distance is substantially a quarter-wavelength of a pre-selected detector wavelength, and wherein the infrared absorber pixel structure and the substrate are configured to act as a quarter-wave resonant cavity.

6. The device of claim 1 further comprising a vacuum enclosure coupled to the substrate to thereby enclose the infrared absorber pixel structure.

7. A focal plane array assembly comprising a plurality of detector elements wherein the plurality of detector elements each comprise:

a thermoelectric detector comprising an infrared absorber pixel structure comprising a pixel surface area,

the infrared absorber pixel structure coupled to at least one thermoelectric structure at a hot junction,

a microlens element configured to collect and focus infrared energy of a predetermined spectrum upon the pixel surface area, and,

a read out integrated circuit.

8. The assembly of claim 7 wherein the read out integrated circuit, comprises a SiGe BiCMOS readout integrated circuit fabricated in a set of SiGe BiCMOS semiconductor processing steps coupled to the at least one thermoelectric structure at a cold junction.

9. The device of claim 7 wherein the at least one thermoelectric structure comprises at least one of bismuth-telluride, antimony-telluride, lead telluride, polysilicon, germanium, skutterudite, a nano-composite material, and a super-lattice structure.

10. The device of claim 7 wherein the substrate comprises a reflector.

11. The device of claim 7 wherein the first distance is substantially a quarter-wavelength of a pre-selected detector wavelength, and wherein the infrared absorber pixel structure and the substrate are configured to act as a quarter-wave resonant cavity.

12. The device of claim 7 further comprising a vacuum enclosure coupled to the substrate to thereby enclose the infrared absorber pixel structure.