High sensitivity infrared sensing apparatus and related method thereof

• US 6,900,440 B2
• Filed: 02/26/2001
• Issued: 05/31/2005
• Est. Priority Date: 02/24/2000
• Status: Expired due to Fees

• Current Assignee: University of Virginia Patent Foundation (University of Virginia)
• Original Assignee: University of Virginia Patent Foundation (University of Virginia)
• Inventors: Blalock, Travis N., Reed, Michael L.
• Primary Examiner(s): Gabor, Otilia
• Application Number:
  US10/204,676
• Publication Number:
  US 20030141453A1
• Time in Patent Office: 1,555 Days
• Field of Search: 250/338.1, 250/332, 250/338.4, 250/338.5, 250/339.02, 250/343, 250/352, 250/370.01, 250/370.08, 250/495.1, 338/18, 438/53, 438/113
• US Class Current: 250/338.1
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: G01J 5/06 Arrangements for eliminating effects of disturbing radiation; Arrangements for compensating changes in sensitivity for adjusting of solid angle of collected radiation G01J5/07; means for wavelength selection G01J5/0801
• CPC Class Codes: G01J 5/10 using electric radiation detectors
• CPC Class Codes: G01J 5/20 using resistors, thermistors or semiconductors sensitive to radiation, e.g. photoconductive devices

Abstract

The infrared (IR) sensing apparatus (101) and related method achieves improvement over traditional infrared sensors by levitating or suspending the IR platform (103) to reduce the loss of IR energy, which normally dissipates in the form of heat. The levitating IR sensitive platform (123) of the present invention has no contact with the substrate (110) during energy absorption, thus eliminating a substantial disadvantage existing in the conventional systems proposed heretofore.

Claims

1. An IR energy sensing apparatus comprising:

a substrate;

an IR energy sensor member for receiving incident IR energy;

a readout circuit operatively connected to said substrate, whereby said readout circuit being adapted for measuring level of incident IR energy received by said sensor member; and

a levitation mechanism operatively connected to said sensor member for levitating said sensor member, said levitated sensor member having no physical or thermal contact while receiving incident IR energy, wherein;

said levitation mechanism is energized at a first level, said levitation mechanism causes said sensor member to levitate proximately-spaced from said substrate without making physical contact with said substrate, said readout circuit, or any other structures; and

said levitation mechanism is energized at a second level, said levitation mechanism repositions said sensor member, whereby said sensor member makes physical contact with said readout circuit so as to form a direct electrical coupling contact between said sensor member, whereby said readout circuit is capable of interrogating said sensor member.

2. The sensing apparatus according to claim 1, wherein:

said IR energy sensor member receives the incident IR energy for a predetermined duration thereby providing an absorption period, said absorption period occurring at least in part while said sensor member is in said proximately-spaced position.

3. The sensing apparatus according to claim 2 wherein:

said readout circuit interrogates said sensor member one or more times as said sensor member is initially electrically coupled thereby providing a post-absorption readout.

4. The sensing apparatus according to claim 3 wherein:

said sensor member makes physical contact with said readout circuit for a predetermined duration thereby providing a thermal quenching period, whereby heat dissipates from said sensor member by thermal conduction to said readout circuit and substrate.

5. The sensing apparatus according to claim 4, wherein:

said readout circuit interrogates said sensor member one or more times after said quenching period while said sensor is in direct electrical coupling contact providing a post-quench readout, whereby said post-quench readout can serve as baseline readout measurement for future cycles.

6. The sensing apparatus according to claim 1, wherein the incident IR energy varies the electrical characteristic of said sensor member.

7. The sensing apparatus according to claim 1, wherein:

said readout circuit is adapted for measuring the level of received incident IR energy according to the varied electrical characteristic of said sensor member.

8. The sensing apparatus according to claim 7, wherein said varied electrical characteristic includes a property selected from the group consisting of:

electrical resistance, electrical capacitance, electrical voltage, electrical inductance, and electrical current.

9. The sensing apparatus according to claim 1, wherein the incident IR energy varies the mechanical characteristic of said sensor member.

10. The sensing apparatus according to claim 1, wherein said sensor member is selected from a group consisting of:

pyroelectric device, bolometer device, thermocouple device, thermopile device, thermo IR detecting device, photon detector, piezoelectric device, CCD, and CMOS.

11. The sensing apparatus according to claim 1, wherein said sensor member comprises an absorptive material comprising a polycrystalline semiconductor layer.

12. The sensing apparatus according to claim 1, wherein said sensor member is comprised of a material selected from the group consisting of:

titanium, titanium oxide, vanadium, vanadium oxide, amorphous silicon, alpha-silicon (α

Si), and vanadium oxide including an oxygen content less than in VO₂.

13. The sensing apparatus according to claim 1, wherein said levitation mechanism is a plurality of electromagnetic field generators, wherein said electromagnetic fields are energized from a group consisting of:

electrostatic forces, magnetostatic forces, and various dynamic electromagnetic forces.

14. The sensing apparatus according to claim 1, wherein said levitation mechanism comprises:

dielectric fingers attached to said sensor member; and

stator electrode fingers mounted to said substrate, wherein said dielectric fingers and said electrode fingers are in an interdigitated relationship with one another.

15. An IR sensing apparatus comprising:

a substrate;

an IR sensor member for receiving incident IR energy;

a readout circuit operatively connected to said substrate, whereby said readout circuit being adapted for measuring level of incident IR energy received by said sensor member; and

a levitation mechanism operatively connected to said sensor member for levitating said sensor member, said levitated sensor member having no physical or thermal contact while receiving incident IR energy, wherein;

when said levitation mechanism is energized said levitation mechanism causes said sensor member to levitate proximately-spaced from said substrate without making physical contact with said substrate, said readout circuit, or any other structures, whereby an indirect electrical coupling between said sensor member and said readout circuit is formed, whereby said readout circuit is capable of interrogating said sensor member;

said IR energy sensor member receives the incident IR energy for a predetermined duration thereby providing an absorption period, said absorption period occurring at least in part while said sensor member is in said proximately-spaced position;

said readout circuit interrogates said sensor member one or more times as said sensor member is indirectly electrically coupled thereby providing a post-absorption readout; and

when said levitation mechanism is energized at a second level, said levitation mechanism repositions said sensor member, whereby said sensor member makes physical contact with said readout circuit for a predetermined duration thereby providing a thermal quenching period, whereby heat dissipates from said sensor member by thermal conduction to said readout circuit and substrate.

16. The sensing apparatus according to claim 15, wherein:

said mechanism is energized at said initial or a different level, said levitation mechanism causes said sensor member to levitate proximately-spaced from said substrate without making physical contact with said substrate, said readout circuit, or any other structures.

17. The sensing apparatus according to claim 16, whereby an indirect electrical coupling between said sensor member and said readout circuit is reestablished to enable said readout circuit to interrogate said sensor member, and wherein:

said readout circuit interrogates said sensor member one or more times after said quenching period while said sensor is in indirect electrical coupling providing a post-quench readout, whereby said post-quench readout can serve as baseline readout measurement for future cycles.

18. An IR energy sensing apparatus comprising:

a substrate;

an IR energy sensor member for receiving incident IR energy;

a readout circuit operatively connected to said substrate, whereby said readout circuit being adapted for measuring level of incident IR energy received by said sensor member;

at least one support structure positioned between said substrate and said sensor member to provide for said sensor member to be proximately-spaced from said substrate, wherein one end of said support being attached to said substrate and the other end being attached to said sensor member; and

a shift actuator operatively connected to said sensor member, wherein;

said shift actuator is energized at a first level said shift actuator allows said sensor member to remain in a proximately-spaced distance from said substrate without making electrical contact with said readout circuit; and

said shift actuator is energized at a second level, said shift actuator causes said sensor member to reposition, whereby said sensor member makes physical contact with said readout circuit so as to form a direct electrical coupling contact between said sensor member, whereby said readout circuit being capable of interrogating said energy sensor member.

19. The sensing apparatus according to claim 18, wherein:

said IR energy sensor member receives the incident IR energy for a predetermined duration thereby providing an absorption period, said absorption period occurring at least in part while said sensor member is in said proximately-spaced position.

20. The sensing apparatus according to claim 19, wherein:

said readout circuit interrogates said sensor member one or more times as said sensor member is initially electrically coupled thereby providing a post-absorption readout.

21. The sensing apparatus according to claim 20, wherein:

said sensor member makes physical contact with said readout circuit for a predetermined duration thereby providing a thermal quenching period, whereby heat dissipates from said sensor member by thermal conduction to said readout circuit and substrate.

22. The sensing apparatus according to claim 21, wherein:

said readout circuit interrogates said sensor member one or more times after said quenching period while said sensor is in direct electrical coupling contact providing a post-quench readout, whereby said post-quench readout can serve as baseline readout measurement for future cycles.

23. An IR energy sensing apparatus comprising:

a substrate;

an IR energy sensor member for receiving incident IR energy;

a readout circuit adapted for measuring level of incident IR energy received by said sensor;

at least one support structure positioned between said substrate and said sensor member to provide for said sensor member to be proximately-spaced from said substrate, wherein one end of said support being attached to said substrate and the other end being attached to said sensor member; and

a shift actuator operatively connected to said sensor member, wherein while said shift actuator is energized at a first level said shift actuator allows said sensor member to remain in a proximately-spaced distance from said substrate without making electrical contact with said readout circuit, whereby an indirect electrical coupling between said sensor member and said readout circuit is formed, whereby said readout circuit is capable of interrogating said sensor member wherein;

said IR energy sensor member receives the incident IR energy for a predetermined duration thereby providing an absorption period, said absorption period occurring at least in part while said sensor member is in said proximately-spaced position;

said readout circuit interrogates said sensor member one or more times as said sensor member is indirectly electrically coupled thereby providing a post-absorption readout; and

said shift actuator is energized at a second level, said shift actuator repositions said sensor member, whereby said sensor member makes physical contact with said readout circuit for a predetermined duration thereby providing a thermal quenching period, whereby heat dissipates from said sensor member by thermal conduction to said readout circuit and substrate.

24. The sensing apparatus according to claim 23, wherein:

said shift actuator is energized at said initial or a different level, said shift actuator causes said sensor member to move to proximately-spaced distance from said substrate without making electrical contact with said readout circuit.

25. The sensing apparatus according to claim 24, whereby an indirect electrical coupling between said sensor member and said readout circuit is reestablished to enable said readout circuit to interrogate said sensor member;

and wherein;

said readout circuit interrogates said sensor member one or more times after said quenching period while said sensor is in indirect electrical coupling providing a post-quench readout, whereby said post-quench readout can serve as baseline readout measurement for future cycles.

26. A method of sensing IR energy comprising the steps of:

a) providing a substrate;

b) providing a readout circuit;

c) receiving incident IR energy using an IR energy sensor member; and

d) levitating said IR energy sensor member, said levitated sensor member having no physical or thermal contact while receiving IR energy, whereby;

said sensor member is levitated to a first position proximately-spaced from said substrate and said readout circuit so as to avoid any physical contact with said substrate, said readout circuit, or any other structures, and said method further comprising the step of;

periodically levitating said sensor member to a second position, whereby said sensor member is in direct electrical coupling contact with said readout circuit, whereby said readout circuit is capable of interrogating said sensor member.

27. The method of sensing IR energy according to claim 26, wherein;

said receiving incident IR energy step is carried out for a predetermined duration thereby providing an absorption period, said absorption period occurring at least in part while said sensor member is in said proximately-spaced position.

28. The method of sensing IR energy according to claim 27, wherein:

said method further includes interrogating said sensor member one or more times as said sensor member is initially electrically coupled thereby providing a post-absorption readout.

29. The method of sensing IR energy according to claim 28, wherein:

said step for levitating said sensor member at second position is carried out for a predetermined duration thereby providing thermal quenching period, whereby heat dissipates from said sensor member by thermal conduction to said readout circuit and substrate.

30. The method of sensing IR energy according to claim 29, wherein:

said method further includes interrogating said readout circuit one or more times after said quenching period while said sensor is in direct electrical coupling contact providing a post-quench readout, whereby said post-quench readout can serve as baseline readout measurement for future cycles.

31. A method of sensing IR energy comprising the steps of:

a) providing a substrate;

b) providing a readout circuit;

c) receiving incident IR energy using an IR energy sensor member; and

d) levitating said IR energy sensor member, said levitated sensor member having no physical or thermal contact while receiving IR energy, whereby said sensor member is proximately-spaced from said substrate and said readout circuit so as to avoid any physical contact with said substrate, said readout circuit, or any other structures, whereby the spacing provides an indirect electrical coupling between said sensor member and said readout circuit, whereby said readout circuit is capable of interrogating said sensor member; and

wherein

said receiving incident IR energy step is carried out for a predetermined duration thereby providing an absorption period, said absorption period occurring at least in part while said sensor member is in said proximately-spaced position;

said method further includes interrogating said sensor member one or more times as said sensor member is indirectly electrically coupled thereby providing a post-absorption readout;

said method further includes periodically levitating said sensor member to a second position, whereby said sensor member makes physical contact with said readout circuit for a predetermined duration thereby providing a thermal quenching period, whereby heat dissipates from said sensor member by thermal conduction to said readout circuit and substrate.

32. The method of sensing according to claim 31, wherein:

levitating said sensor member to return to a proximately-spaced position from said substrate without making physical contact with said substrate, said readout circuit, or any other structures.

33. The method of sensing according to claim 32, whereby an indirect electrical coupling between said sensor member and said readout circuit is reestablished to enable said readout circuit to interrogate said sensor member, and further comprising the step of:

interrogating said sensor member one or more times after said quenching period while said sensor is in indirect electrical coupling providing a post-quench readout, whereby said post-quench readout can serve as baseline readout measurement for future cycles.

34. A method of sensing IR energy comprising the steps of:

a) providing a substrate;

b) providing a readout circuit;

c) receiving incident IR energy using an IR energy sensor member;

d) physically suspending said IR energy sensor member at a first position proximately-spaced from said substrate and said readout circuit; and

e) physically suspending said sensor member at a second position, periodically, whereby said sensor member is in direct electrical coupling contact with said readout circuit, whereby said readout circuit is capable of interrogating said sensor member.

35. The method of sensing IR energy according to claim 34, wherein

said receiving incident IR step is carried out for a predetermined duration thereby providing an absorption period, said absorption period occurring at least in part while said sensor member is in said proximately-spaced position.

36. The method of sensing IR energy according to claim 35, wherein said method further includes interrogating said sensor member one or more times as said sensor member is initially electrically coupled thereby providing a post-absorption readout.

37. The method of sensing IR energy according to claim 36, wherein:

said step for suspending said sensor member at second position is carried out for a predetermined duration thereby providing a thermal quenching period.

38. The method of sensing IR energy according to claim 37, whereby heat dissipates from said sensor member by thermal conduction to said readout circuit and substrate;

and wherein;

said method further includes interrogating said readout circuit one or more times after said quenching period while said sensor member is in direct electrical coupling contact providing a post-quench readout, whereby said post-quench readout can serve as baseline readout measurement for future cycles.

39. A method of sensing IR energy comprising the steps of:

a) providing a substrate;

b) providing a readout circuit;

c) receiving incident IR energy using an IR energy sensor member; and

d) physically suspending said IR energy sensor member proximately-spaced from said substrate and said readout circuit, whereby the spacing provides an indirect electrical coupling between said sensor member and said readout circuit, whereby said readout circuit is capable of interrogating said sensor member;

wherein;

said receiving incident IR energy step is carried out for a predetermined duration thereby providing an absorption period, said absorption period occurring at least in part while said sensor member is in said proximately-spaced position;

said method further includes interrogating said sensor member one or more times as said sensor member is indirectly electrically coupled thereby providing a post-absorption readout; and

said method further includes periodically suspending said sensor member to a second position, whereby said sensor member makes physical contact with said readout circuit for a predetermined duration thereby providing a thermal quenching period, whereby heat dissipates from said sensor member by thermal conduction to said readout circuit and substrate.

40. The method of sensing IR energy according to claim 39, further comprising:

suspending said sensor member to return to a proximately-spaced position from said substrate without making electrical contact with said readout circuit.

41. The method of sensing IR energy according to claim 40, whereby an indirect electrical coupling between said sensor member and said readout circuit is reestablished to enable said readout circuit to interrogate said sensor member, wherein said method further comprises:

interrogating said sensor member one or more times after said quenching period while said sensor is in indirect electrical coupling providing a post-quench readout, whereby said post-quench readout can serve as baseline readout measurement for future cycles.