Method and apparatus for compensating a radiation sensor for ambient temperature variations

• US 6,515,285 B1
• Filed: 02/11/2000
• Issued: 02/04/2003
• Est. Priority Date: 10/24/1995
• Status: Expired due to Term

• Current Assignee: BAE Systems Information and Electronic Systems Integration Incorporated (BAE Systems Plc)
• Original Assignee: Lockheed Martin IR Imaging Systems, Inc. (Martin Marietta Corporation)
• Inventors: Marshall, Charles M., Butler, Neal R.
• Primary Examiner(s): Hannaher, Constantine
• Application Number:
  US09/502,840
• Time in Patent Office: 1,089 Days
• Field of Search: 250/339.03, 250/339.04, 250/352, 250/370.15
• US Class Current: 250/352
• CPC Class Codes: G01J 5/20 using resistors, thermistors or semiconductors sensitive to radiation, e.g. photoconductive devices
• CPC Class Codes: H01L 25/042 the devices being arranged next to each other solar cells H01L31/042
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H01L 31/09 Devices sensitive to infrared, visible or ultraviolet radiation H01L31/101 takes precedence
• CPC Class Codes: H04N 25/616 involving a correlated sampling function, e.g. correlated double sampling [CDS] or triple sampling
• CPC Class Codes: H04N 25/63 applied to dark current
• CPC Class Codes: H04N 25/671 for non-uniformity detection or correction
• CPC Class Codes: H04N 25/68 applied to defects
• 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

Methods and apparatus for compensating a radiation sensor for ambient temperature variations. Ambient temperature variations may produce undesirable artifacts in electronic signals output by a radiation sensor. In some cases, such artifacts may detrimentally reduce the dynamic range of the sensor and/or processing circuitry associated with the sensor with respect to radiation of interest. The radiation sensor may be compensated for such undesirable artifacts by, for example, adding an appropriate offset to a sensor bias voltage or a sensor bias current, and/or controlling a temperature of the radiation sensor, based on variations in the ambient temperature.

Claims

1. A method of controlling a temperature of at least one radiation sensor, the radiation sensor outputting image signals based on detected radiation, the method comprising an act of varying the temperature of the at least one radiation sensor in response to a change in an ambient temperature proximate to the at least one radiation sensor, such that an X degree change in the ambient temperature causes a Y degree change in the temperature of the at least one radiation sensor, wherein X and Y are different.

2. The method of claim 1, wherein X and Y have opposite polarities.

3. A method of controlling a temperature of at least one radiation sensor, the radiation sensor outputting image signals based on detected radiation, the method comprising an act of varying the temperature of the at least one radiation sensor in response to a change in an ambient temperature proximate to the at least one radiation sensor, wherein the act of varying the temperature of the at least one radiation sensor includes acts of:

generating a temperature sensitive reference signal that varies in response to changes in the ambient temperature;

measuring the temperature of the at least one radiation sensor;

making a comparison of the measured temperature of the at least one radiation sensor to the temperature sensitive reference signal; and

controlling the temperature of the at least one radiation sensor based on the comparison.

4. The method of claim 3, wherein the at least one radiation sensor is formed on a substrate enclosed in a package, and wherein:

the act of measuring the temperature of the at least one radiation sensor includes an act of measuring a temperature of the substrate enclosed in the package; and

the act of generating a temperature sensitive reference signal includes an act of generating the temperature sensitive reference signal based on the ambient temperature outside of and proximate to the package.

5. An apparatus comprising:

at least one radiation sensor to output image signals based on detected radiation, the at least one radiation sensor including a plurality of resistive microbolometer elements arranged as a sensor array, wherein the sensor array is enclosed in a package; and

a temperature sensitive reference circuit for providing a temperature sensitive reference signal, the temperature sensitive reference circuit comprising;

at least one temperature sensor to provide the temperature sensitive reference signal based on an ambient temperature proximate to the at least one radiation sensor;

at least one power supply to provide power to the at least one temperate sensor; and

at least one resistor coupled to the at least one temperature sensor and the at least one power supply,

wherein the temperature sensor reference circuit is not enclosed in the package.

6. The combination of claim 5, wherein the package and the temperature sensitive reference circuit are mounted on a same circuit board.

7. In an apparatus including at least one radiation sensor to output image signals based on detected radiation, a temperature control circuit for controlling a temperature of the at least one radiation sensor, the temperature control circuit controlling the temperature of the at least one radiation sensor based on a measured temperature of the at least one radiation sensor and a measured ambient temperature proximate to the at least one radiation sensor, such that an X degree change in the ambient temperature causes a Y degree change in the temperature of the at least one radiation sensor, wherein X and Y are different.

8. The temperature control circuit of claim 7, in combination with the at let one radiation sensor.

9. In an apparatus including at least one radiation sensor to output image signals based on detected radiation, a temperature control circuit for controlling a temperature of the at least one radiation sensor, the temperature control circuit controlling the temperature of the at let one radiation sensor based on a measured temperature of the at least one radiation sensor and a measured ambient temperature proximate to the at least one radiation sensor, such that as X degree change in the ambient temperature causes a Y degree change in the temperature of the at least one radiation sensor, wherein X and Y have opposite polarities.

10. A method of compensating at least one radiation sensor for ambient temperature variations, comprising an act of controlling at least one of a radiation sensor bias voltage and a radiation sensor bias current of the at least one radiation sensor in response to changes in an ambient temperature.

11. The method of claim 10, wherein the act of controlling at least one of a radiation sensor bias voltage and a radiation sensor bias current of the at least one radiation sensor in response to changes in the ambient temperature includes an act of controlling the radiation senior bias voltage of the at least one radiation sensor in response to changes in the ambient temperature.

12. The method of claim 10, wherein the act of controlling at least one of a radiation sensor bias voltage and a radiation sensor bias current of the at least one radiation sensor in response to changes in the ambient temperature includes an act of controlling the radiation sensor bias current of the at least one radiation sensor in response to changes in the ambient temperature.

13. A method of compensating at least one radiation sensor for ambient temperature variations, comprising an act of controlling at least one of a radiation sensor bias voltage, a radiation sensor bias current, and a temperature of the at least one radiation sensor in response to changes in an ambient temperature,

wherein the at least one radiation sensor is enclosed in a radiation shield, and wherein the act of controlling at least one of a radiation sensor bias voltage, a radiation sensor bias current, and a temperature of the at least one radiation sensor in response to changes in the ambient temperature includes an act of controlling a radiation shield temperature of the radiation shield.

14. A method of compensating a plurality of radiation sensors for ambient temperature variations, comprising an act of controlling at least one of a radiation sensor bias voltage, a radiation sensor bias current, and a temperature of the plurality of radiation sensors in response to changes in an ambient temperature, wherein the act of controlling at least one of a radiation sensor bias voltage, a radiation sensor bias current, and a temperature of the plurality of radiation sensors in response to changes in the ambient temperature includes an act of determining an average temperature of at least some of the plurality of radiation sensors.

15. The method of claim 14, wherein the act of controlling at least one of a radiation sensor bias voltage, a radiation sensor bias current, and a temperature of the at least one radiation sensor in response to changes in the ambient temperature includes an act of controlling at least one of the radiation sensor bias voltage, the radiation sensor bias current, and the temperature of at least one of the plurality of radiation sensors based on the average temperature of at least some of the plurality of radiation sensors.

16. A method of compensating at least one radiation sensor for ambient temperature variations, comprising an act of controlling at least one of a radiation sensor bias voltage, a radiation sensor bias current, and a temperature of the at least one radiation sensor in response to changes in an ambient temperature,

wherein the at least one radiation sensor is enclosed in a package, and wherein the act of controlling at least one of a radiation sensor bias voltage, a radiation sensor bias current, and a temperature of the at least one radiation sensor in response to changes in the ambient temperature includes an act of determining the ambient temperature that exists inside the package.

17. The method of claim 16, wherein the act of controlling at least one of a radiation sensor bias voltage, a radiation sensor bias current, and a temperature of the at least one radiation sensor in response to changes in the ambient temperature includes an act of controlling at least one of the radiation sensor bias voltage, the radiation sensor bias current, and the temperature of the at least one radiation sensor based on a comparison of the temperature of the at least one radiation sensor and the determined ambient temperature.

18. A method of compensating at least one radiation sensor enclosed in a package for ambient temperature variations, comprising acts of:

controlling at least one of a radiation sensor bias voltage, a radiation sensor bias current, and a temperature of the at least one radiation sensor in response to changes in an ambient temperature; and

determining the ambient temperature that exists outside and proximate to the package; and

wherein the act of controlling at least one of a radiation sensor bias voltage, a radiation sensor bias current, and a temperature of the at least one radiation sensor in response to changes in the ambient temperature includes an act of controlling at least one of the radiation sensor bias voltage, the radiation sensor bias current, and the temperature of the at least one radiation sensor based on a comparison of the temperature of the at least one radiation sensor and the determined ambient temperature.

19. An apparatus, comprising;

a controller to compensate at least one radiation sensor for ambient temperature variations, the controller controlling at least one of a radiation sensor bias voltage and a radiation sensor bias current of the at least one radiation sensor in response to changes in an ambient temperature.

20. The apparatus of claim 19, wherein the controller controls the radiation sensor bias voltage of the at least one radiation sensor in response to changes in the ambient temperature.

21. The apparatus of claim 19, wherein the controller controls the radiation sensor bias current of the at least one radiation sensor in response to changes in the ambient temperature.

22. An apparatus, comprising:

a controller to compensate at least one radiation sensor enclosed in a radiation shield for ambient temperature variations, the controller controlling at least one of a radiation sensor bias voltage and a radiation sensor bias current of the at least one radiation sensor in response to changes in an ambient temperature, wherein the controller controls a radiation shield temperature of the radiation shield in response to changes in the ambient temperature.

23. An apparatus, comprising:

a controller to compensate a plurality of radiation sensors for ambient temperature variations, the controller controlling at least one radiation sensor bias voltage, a radiation sensor bias current, and a temperature of the plurality of radiation sensors in response to changes in an ambient temperature,

wherein the controller determines an average temperature of at least some of the plurality of radiation sensors.

24. The apparatus of claim 23, wherein the controller controls at least one of the radiation sensor bias voltage, the radiation sensor bias current, and the temperature of at least one of the plurality of radiation sensors based on the average temperature of at least some of the plurality of radiation sensors.

25. An apparatus, comprising:

a controller to compensate at least one radiation sensor enclosed in a package for ambient temperature variations, the controller controlling at least one of a radiation sensor bias voltage, a radiation sensor bias current, and a temperature of the at least one radiation sensor in response to changes in the ambient temperature, wherein the controller determines the ambient temperature that exists inside the package.

26. The apparatus of claim 25, wherein the controller controls at least one of the radiation sensor bias voltage, the radiation sensor bias current, and the temperature of the at least one radiation sensor based on a comparison of the temperature of the at least one radiation sensor and the determined ambient temperature.

27. An apparatus, comprising:

a controller to compensate at least one radiation sensor enclosed in a package for ambient temperature variations, the controller controlling at least one of a radiation sensor bias voltage, a radiation sensor bias current, and a temperature of the at least one radiation sensor in response to changes in the ambient temperature,

wherein the controller determines the ambient temperature that exists outside and proximate to the package; and

wherein the controller controls at least one of the radiation sensor bias voltage, the radiation sensor bias current, and the temperature of the at least one radiation sensor based on a comparison of the temperature of the at least one radiation sensor and the determined ambient temperature.

28. A method of compensating a plurality of radiation sensors for ambient temperature variations, the plurality of radiation sensors providing a respective plurality of output signals, the method comprising acts of:

controlling at least one of a radiation sensor bias voltage, a radiation sensor bias current, and a temperature of at least one of the plurality of radiation sensors in response to changes in an ambient temperature; and

determining an average signal of at least some of the plurality of output signals, the average signal representing an average temperature of at last some of the plurality of radiation sensors.

29. The method of claim 28, wherein the act of controlling at least one of a radiation sensor bias voltage, a radiation sensor bias current, and a temperature of the at least one of the plurality of radiation sensors in response to changes in the ambient temperature includes an act of controlling at least one of the radiation sensor bias voltage, the radiation sensor bias current, and the temperature of the at least one of the plurality of radiation sensors based on the avenge signal.

30. An apparatus, comprising:

a controller to compensate a plurality of radiation sensors for ambient temperature variations, the plurality of radiation sensors providing a respective plurality of output signals, the controller controlling at least one of a radiation sensor bias voltage, a radiation sensor bias current, and a temperature of at least one of the plurality of radiation sensors in response to changes in an ambient temperature,

wherein the controller determines an average signal of at least some of the plurality of output signals, the average signal representing an average temperature of at least some of the plurality of radiation sensors.

31. The apparatus of claim 30, wherein the controller controls at least one of the radiation sensor bias voltage, the radiation sensor bias current, and the temperature of the at least one of the plurality of radiation sensors based on the average signal.

32. A method for thermally stabilizing an array of sensors, each sensor of the array having a signal output responsive to temperature, the method comprising acts of:

determining an average temperature of the array based on the signal output of at least some sensors of the array;

generating a feedback signal proportional to the average temperature; and

thermally stabilizing the array at at least one predetermined temperature based on the feedback signal.

33. The method of claim 32, wherein the act of thermally stabilizing includes an act of applying the feedback signal to a thermoelectric device coupled to the array.