Per-pixel dark reference bolometer
First Claim
1. A thermal imaging device comprising:
- a read-out integrated circuit (ROIC) substrate; and
a microbolometer array disposed on the ROIC substrate and including a plurality of detector elements arranged in a two-dimensional array, each detector element including an imaging microbolometer and a reference microbolometer, the imaging microbolometer being configured to receive electromagnetic radiation from a viewed scene and to produce an image signal in response to receiving the electromagnetic radiation, the image signal including a component produced due to thermal noise in the respective detector element, and the reference microbolometer being shielded from receiving the electromagnetic radiation and configured to produce a reference signal indicative of the thermal noise, each detector element further including circuitry configured to subtract the reference signal from the image signal to produce a corrected image signal, the circuitry including a pair of complementary transistors connected in series between the reference microbolometer and the imaging microbolometer,wherein the thermal imaging device is configured to produce an image of the viewed scene from the corrected image signals from the plurality of detector elements.
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Accused Products
Abstract
Microbolometer arrays incorporating per-pixel dark reference structures for non-uniformity correction. In one example a thermal imager includes a device substrate, a microbolometer array disposed on the device substrate and including a plurality of detector elements arranged in a two-dimensional array, each detector element including an imaging microbolometer and a reference microbolometer, the imaging microbolometer being configured to receive electromagnetic radiation from a viewed scene and to produce an image signal in response to receiving the electromagnetic radiation, the image signal including a component produced due to thermal noise in the respective detector element, and the reference microbolometer being shielded from receiving the electromagnetic radiation and configured to produce a reference signal indicative of the thermal noise, wherein the thermal imaging device is configured to produce an image of the viewed scene based on a combination of the image signals and the reference signals from the plurality of detector elements.
9 Citations
18 Claims
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1. A thermal imaging device comprising:
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a read-out integrated circuit (ROIC) substrate; and a microbolometer array disposed on the ROIC substrate and including a plurality of detector elements arranged in a two-dimensional array, each detector element including an imaging microbolometer and a reference microbolometer, the imaging microbolometer being configured to receive electromagnetic radiation from a viewed scene and to produce an image signal in response to receiving the electromagnetic radiation, the image signal including a component produced due to thermal noise in the respective detector element, and the reference microbolometer being shielded from receiving the electromagnetic radiation and configured to produce a reference signal indicative of the thermal noise, each detector element further including circuitry configured to subtract the reference signal from the image signal to produce a corrected image signal, the circuitry including a pair of complementary transistors connected in series between the reference microbolometer and the imaging microbolometer, wherein the thermal imaging device is configured to produce an image of the viewed scene from the corrected image signals from the plurality of detector elements. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A thermal imaging method comprising:
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receiving electromagnetic radiation from a viewed scene at an imaging microbolometer of each of a plurality of detector elements of a microbolometer array; producing, from the imaging microbolometer included in each of the plurality of detector elements, an image signal from a combination of the received electromagnetic radiation and thermal noise in the respective detector element; producing, from a reference microbolometer included in each of the plurality of detector elements, a reference signal based on the thermal noise, the reference microbolometer being shielded from receiving the electromagnetic radiation; for each detector element, subtracting the reference signal from the image signal using a pair of complementary transistors connected in series between the reference microbolometer and the imaging microbolometer to produce a corrected image signal; and producing an image of the viewed scene based on the corrected image signals from the plurality of detector elements. - View Dependent Claims (10)
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11. A thermal imaging device comprising:
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a read-out integrated circuit (ROIC) substrate; a microbolometer array disposed on the ROIC substrate and including a two-dimensional array of detector elements, each detector element including; a reference resistor formed on a first surface of the ROIC substrate, the reference resistor being formed of a thermally sensitive material and configured to produce a reference signal representative of thermal noise in the detector element, a reflector disposed over the reference resistor and the first surface of the ROIC substrate, the reflector being formed of an infrared reflecting material and configured to shield the reference resistor from receiving electromagnetic radiation from a scene viewed by the microbolometer array, and an imaging microbolometer suspended above the reflector and thermally isolated from the ROIC substrate by a pair of thermal isolation legs, the imaging microbolometer including a layer of the thermally sensitive material supported by a support layer, and being configured to receive the electromagnetic radiation from the viewed scene and to produce an image signal based on the received electromagnetic radiation and the thermal noise in the detector element; and circuitry formed in the ROIC substrate and coupled to the microbolometer array and configured to, for each detector element, subtract the reference signal from the image signal to produce a corrected image signal, and to produce an image of the viewed scene based on the corrected image signals from the plurality of detector elements, the circuitry including a pair of complementary transistors connected in series between the reference microbolometer and the imaging microbolometer. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18)
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Specification