Thermography camera tuned to detect absorption of infrared radiation in a selected spectral bandwidth
First Claim
1. A device comprising:
- a focal plane array comprising a plurality of quantum well infrared photo detectors (QWIPs) adapted to receive radiation from a survey scene, wherein;
the plurality of QWIPs comprises a plurality of quantum well layers configured to generate a desired photocurrent in response to the radiation and a plurality of barrier layers alternating with the quantum well layers,an amount of doping of the quantum well layers, a spacing of quantum wells in the quantum well layers, and thicknesses of the quantum well layers and the barrier layers are selected for the QWIPs to tune the focal plane array to have a limited spectral bandwidth with a peak response within a wavelength range of 10.4 μ
m to 10.8 μ
m and a full width half maximum spectral bandwidth of less than 0.7 μ
m in response to the radiation, andthe less than 0.7 μ
m spectral bandwidth of the focal plane array is selected to reduce signal noise substantially outside the wavelength range of 10.4 μ
m to 10.8 μ
m associated with operation of the focal plane array and/or an optical band pass filter.
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Accused Products
Abstract
An infrared camera system is provided to detect absorption of infrared radiation in a selected spectral bandwidth. In one example, an infrared camera system includes a lens adapted to receive infrared radiation from a survey scene comprising one or more gasses. The infrared camera system also includes a focal plane array comprising a plurality of quantum well infrared photo detectors (QWIPs). The QWIPs are tuned to detect a limited spectral bandwidth of the infrared radiation corresponding to at least a portion of an infrared absorption band of the one or more gasses. The infrared camera system also includes an optical band pass filter positioned substantially between the lens and the focal plane array. The optical band pass filter is adapted to filter the infrared radiation to a wavelength range substantially corresponding to the limited spectral bandwidth of the QWIPs before the infrared radiation is received by the focal plane array.
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Citations
20 Claims
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1. A device comprising:
a focal plane array comprising a plurality of quantum well infrared photo detectors (QWIPs) adapted to receive radiation from a survey scene, wherein; the plurality of QWIPs comprises a plurality of quantum well layers configured to generate a desired photocurrent in response to the radiation and a plurality of barrier layers alternating with the quantum well layers, an amount of doping of the quantum well layers, a spacing of quantum wells in the quantum well layers, and thicknesses of the quantum well layers and the barrier layers are selected for the QWIPs to tune the focal plane array to have a limited spectral bandwidth with a peak response within a wavelength range of 10.4 μ
m to 10.8 μ
m and a full width half maximum spectral bandwidth of less than 0.7 μ
m in response to the radiation, andthe less than 0.7 μ
m spectral bandwidth of the focal plane array is selected to reduce signal noise substantially outside the wavelength range of 10.4 μ
m to 10.8 μ
m associated with operation of the focal plane array and/or an optical band pass filter.- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method of manufacturing a device, the method comprising:
forming a focal plane array comprising a plurality of quantum well infrared photo detectors (QWIPs) adapted to receive radiation from a survey scene, wherein; the plurality of QWIPs comprises a plurality of quantum well layers configured to generate a desired photocurrent in response to the radiation and a plurality of barrier layers alternating with the quantum well layers, an amount of doping of the quantum well layers, a spacing of quantum wells in the quantum well layers, and thicknesses of the quantum well layers and the barrier layers are selected for the QWIPs to tune the focal plane array to have a limited spectral bandwidth with a peak response within a wavelength range of 10.4 μ
m to 10.8 μ
m and a full width half maximum spectral bandwidth of less than 0.7 μ
m in response to the radiation, andthe less than 0.7 μ
m spectral bandwidth of the focal plane array is selected to reduce signal noise substantially outside the wavelength range of 10.4 μ
m to 10.8 μ
m associated with operation of the focal plane array and/or an optical band pass filter.- View Dependent Claims (13, 14, 15, 16, 17, 18)
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19. A method of providing an image of a survey scene, the method comprising:
receiving radiation from the survey scene at a focal plane array comprising a plurality of quantum well infrared photo detectors (QWIPs) adapted to receive the radiation, wherein; the plurality of QWIPs comprises a plurality of quantum well layers configured to generate a desired photocurrent in response to the radiation and a plurality of barrier layers alternating with the quantum well layers, an amount of doping of the quantum well layers, a spacing of quantum wells in the quantum well layers, and thicknesses of the quantum well layers and the barrier layers are selected for the QWIPs to tune the focal plane array to have a limited spectral bandwidth with a peak response within a wavelength range of 10.4 μ
m to 10.8 μ
m and a full width half maximum spectral bandwidth of less than 0.7 μ
m in response to the radiation, andthe less than 0.7 μ
m spectral bandwidth of the focal plane array is selected to reduce signal noise substantially outside the wavelength range of 10.4 μ
m to 10.8 μ
m associated with operation of the focal plane array and/or an optical band pass filter; andproviding a plurality of signals from the focal plane array corresponding to an image of the survey scene. - View Dependent Claims (20)
Specification