US5486698A — Thermal imaging system with integrated thermal ch…

Claim 1

Independent Claim 121 words

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.

Claim 2

Dependent Claim 121 words

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.

Claim 3

Dependent Claim 104 words

The thermal sensor of claim 1, wherein the thermal sensitive material and the signal flow path further comprise: a common plate; a pair of thermally sensitive pixel elements, each pixel element electrically coupled on one side with the common plate and on the other side with a respective electrode; a bias electrode for coupling one pixel element to a bias contact pad disposed on the substrate and for supplying a bias voltage to the thermal sensor; and a signal electrode for coupling the other pixel element to a signal contact pad disposed on the substrate and for receiving the signal from the thermal sensor.

Claim 4

Dependent Claim 55 words

The thermal sensor of claim 1, further comprising: at least one address electrode disposed on the substrate for use in selectively deflecting the thermal sensor; and at least one landing pad disposed on the substrate for contacting a portion of the deflected thermal sensor, thereby providing thermal coupling between the thermal sensor and the substrate.

Claim 5

Dependent Claim 21 words

The thermal sensor of claim 1, further comprising a portion of a radiometer for measuring radiant energy from a selected source.

Claim 6

Dependent Claim 120 words

A thermal imaging system for producing an image of a scene, comprising: 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.

Claim 7

Dependent Claim 120 words

A thermal imaging system for producing an image of a scene, comprising: 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.

Claim 8

Dependent Claim 42 words

The system of claim 5, wherein each of the thermal sensors further comprises a pair of electrodes mounted on the substrate with flexible leads which allow selective deflection of the respective thermal sensor to contact the substrate and form the reference signal.

Claim 9

Dependent Claim 38 words

The system of claim 5, wherein the plurality of thermal sensors receive a bias voltage from the substrate and provide a signal to the substrate representative of the amount of thermal radiation incident to the focal plane array.

Claim 10

Dependent Claim 123 words

The system of claim 5, wherein the plurality of thermal sensors provide a signal representative of the amount of thermal radiation incident to the focal plane array, each thermal sensor comprising: a common plate; a pair of thermally sensitive pixel elements, 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, thereby 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 the reference signal representative of the temperature of the substrate.

Claim 11

Dependent Claim 93 words

The system of claim 5, further comprising: a low pass filter for receiving the biased signal and for extracting the DC component of the biased signal representing a signal offset; a comparator for receiving the signal offset and for comparing the signal offset to a reference offset to obtain a control signal; an amplifier for receiving the control signal and producing a drive signal; and a thermoelectric cooler/heater for responding to the drive signal by adjusting the temperature of the substrate, thereby reducing the difference between the signal offset and the reference offset.

Claim 12

Dependent Claim 128 words

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: 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.

Claim 13

Dependent Claim 128 words

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: 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.

Claim 14

Dependent Claim 70 words

The focal plane array of claim 10, wherein the electrodes for each thermal sensor comprise: a bias electrode for coupling one pixel element to a bias contact pad disposed on the substrate and for supplying a bias voltage to the thermal sensor; and a signal electrode for coupling the other pixel element to a signal contact pad disposed on the substrate and for receiving the signal from the thermal sensor.

Claim 15

Dependent Claim 61 words

The focal plane array of claim 10, wherein each thermal sensor comprises: at least one address electrode disposed on the substrate that when activated causes the thermal sensor to selectively deflect; and at least one landing pad disposed on the substrate for contacting a portion of the deflected thermal sensor, thereby providing thermal coupling between the thermal sensor and the substrate.

Claim 16

Dependent Claim 17 words

The focal plane array of claim 10, wherein the pixel elements are formed from a pyroelectric material.

Claim 17

Dependent Claim 18 words

The focal plane array of claim 10, wherein a temperature control circuit adjusts the temperature of the substrate.

Claim 18

Dependent Claim 108 words

The focal plane array of claim 10, wherein a temperature control circuit adjusts the temperature of the substrate, the temperature control circuit further comprising: a low pass filter for receiving the signal and for extracting the DC component of the signal representing a signal offset; a comparator for receiving the signal offset and for comparing the signal offset to a reference offset to obtain a control signal; an amplifier for receiving the control signal and producing a drive signal; and a thermoelectric cooler/heater for responding to the drive signal by adjusting the temperature of the substrate, thereby reducing the difference between the signal offset and the reference offset.

Claim 19

Independent Claim 99 words

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: 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.

Claim 20

Independent Claim 99 words

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: 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.

Claim 21

Dependent Claim 20 words

The method of claim 16, wherein the steps of thermally shunting and detecting are each executed in approximately equal time.

Claim 22

Dependent Claim 27 words

The method of claim 16, wherein the steps of thermally shunting and detecting are executed with the detecting time period substantially longer than the shunting time period.

Claim 23

Dependent Claim 56 words

The method of claim 16, wherein the step of thermally shunting comprises: activating at least one address electrode disposed on the substrate for each thermal sensor; and deflecting each thermal sensor in response to the corresponding activated address electrode until a portion of the thermal sensor contacts at least one landing pad disposed on the substrate.

Claim 24

Dependent Claim 43 words

The method of claim 16, wherein the step of detecting further comprises: deactivating at least one address electrode disposed on the substrate for each thermal sensor; and returning each thermal sensor to an undeflected state for detecting the thermal radiation from the scene.

Claim 25

Dependent Claim 77 words

The method of claim 16, further comprising controlling the temperature of the substrate during the step of detecting, comprising the steps of: extracting the DC component of the biased signal representing a signal offset; comparing the signal offset to a reference offset to obtain a control signal; and driving a thermoelectric cooler/heater in response to the control signal to adjust the temperature of the substrate, thereby reducing the difference between the signal offset and the reference offset.

Claim 26

Dependent Claim 23 words

The method of claim 16, further comprising controlling the temperature of the substrate to adjust the reference signal sensed by the thermal sensors.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1999-01-22	1999-07-24	2000-01-23	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2003-01-22	2003-07-24	2004-01-23	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2007-01-22	2007-07-24	2008-01-23	$7700.00	Window Closed / Lapsed

Thermal imaging system with integrated thermal chopper

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