Thermal imaging system with integrated thermal chopper
First Claim
1. A thermal sensor mounted on a substrate to provide a signal representative of the amount of thermal radiation incident to the thermal sensor, comprising:
- thermal sensitive material for generating a biased signal representing total radiance from the scene and for generating a reference signal by shunting the thermal sensitive material with the substrate;
at least one flexible arm for allowing selective deflection of the thermal sensitive material to contact the substrate and form the reference signal; and
a signal flow path from the thermal sensitive material to a respective contact pad disposed on the substrate; and
the signal flow path providing a reference signal representative of the temperature of the substrate when the thermal sensitive material deflects to contact the substrate.
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Accused Products
Abstract
A thermal imaging system (10) contains a focal plane array (14) including a plurality of thermal sensors (50) mounted on a substrate (52). The focal plane array (14) generates both a reference signal which represents the temperature of the substrate (52) and a biased signal corresponding to the total radiance emitted by a scene (11). Electronics (16) process the reference signal and the biased signal to obtain an unbiased signal representing radiance differences emitted by objects in the scene (11). A thermoelectric cooler/heater (38) may be provided to optimally adjust the temperature of the substrate (52) to improve overall image quality. Each thermal sensor (50) contains an electrode (66 and 68) that electrically couples the thermal sensor (50) to the substrate (52) and also allows the thermal sensor (50) to deflect, contact, and thermally shunt with the substrate (52).
134 Citations
22 Claims
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1. A thermal sensor mounted on a substrate to provide a signal representative of the amount of thermal radiation incident to the thermal sensor, comprising:
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thermal sensitive material for generating a biased signal representing total radiance from the scene and for generating a reference signal by shunting the thermal sensitive material with the substrate; at least one flexible arm for allowing selective deflection of the thermal sensitive material to contact the substrate and form the reference signal; and a signal flow path from the thermal sensitive material to a respective contact pad disposed on the substrate; and the signal flow path providing a reference signal representative of the temperature of the substrate when the thermal sensitive material deflects to contact the substrate. - View Dependent Claims (2, 3, 4)
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5. A thermal imaging system for producing an image of a scene, comprising:
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optics for focusing radiation emitted by the scene on a focal plane array; the focal plane array, including a plurality of thermal sensors mounted on a substrate, for generating a biased signal representing the total radiance from the scene and for generating a reference signal by thermally shunting the thermal sensors to the substrate; electronics for receiving the biased signal and the reference signal and for subtracting the reference signal from the biased signal to obtain an unbiased signal representing radiance differences emitted by objects in the scene; and a display for receiving the unbiased signal and for displaying an image generated in response to the unbiased signal. - View Dependent Claims (6, 7, 8, 9)
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10. A focal plane array including a plurality of thermal sensors mounted on a substrate to provide a signal representative of the amount of thermal radiation incident to the focal plane array, each thermal sensor comprising:
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a common plate; a pair of thermally sensitive pixel elements with each pixel element electrically coupled on one side with the common plate and on the other side with a respective electrode; each electrode coupled to a respective contact pad disposed on the substrate for forming a signal path between the contact pads through the common plate, the pixel elements, and the electrodes; and each electrode comprising a flexible lead that allows the thermal sensor to deflect and contact the substrate for providing a reference signal representative of the temperature of the substrate. - View Dependent Claims (11, 12, 13, 14, 15)
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16. A method for producing an image of a scene using a thermal imaging system with a plurality of thermal sensors mounted on a substrate, comprising the steps of:
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thermally shunting the thermal sensors to the substrate to establish a reference signal representative of the temperature of the substrate; detecting the thermal radiation from the scene to form a biased signal representing the total radiance of the scene; subtracting the reference signal from the biased signal to obtain an unbiased signal representing radiance differences emitted by objects in the scene; and displaying an image in response to the unbiased signal. - View Dependent Claims (17, 18, 19, 20, 21, 22)
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Specification