Patent EP0109712A2 successfully refreshed from Google Patents.
EP0109712A2
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Infrared thermal detector
Assignee: Koninklijke Philips NV
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Filing: 1983-11-15
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Granted: —
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Expires: 2003-11-15
Abstract
Abstract An infrared thermal detector includes an infrared thermal sensing element, a load resistor, and a voltage supply means. The infrared thermal sensing element is a pyroelectric material whose electrical conductivity changes with temperature. The circuit and device parameters are chosen such that the detector will have a flat frequency response over a broad band from dc (0 Hertz) to a high frequency determined by the electronic time constant of the circuit. The detector thus has all the advantages of either a pyroelectric detector without a chopper, or a thermistor bolometer having a fast response time.
Inventors
- 👤 Avner Shaulov
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 17:03
CPC Classifications
G; G01; G01J; G01J5/00; G01J5/10; G01J5/34; H; H10; H10N; H10N15/00; H10N15/10
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
83 words
1 . An infrared thermal detector, characterized in that it comprises: aninfrared thermal sensing element comprising a pyroelectric material whose electrical conductivity changes with temperature, said sensing element having two substantially planar opposite sides on which first and second electrodes are provided, respectively: a load resistor having first and second electrodes, the first electrode of the load resistor being electrically connected to the first electrode of the sensing element; and variable voltage supply means for providing a selectable voltage across the second electrodes.
Claim 2
Dependent Claim
83 words
1 . An infrared thermal detector, characterized in that it comprises: aninfrared thermal sensing element comprising a pyroelectric material whose electrical conductivity changes with temperature, said sensing element having two substantially planar opposite sides on which first and second electrodes are provided, respectively: a load resistor having first and second electrodes, the first electrode of the load resistor being electrically connected to the first electrode of the sensing element; and variable voltage supply means for providing a selectable voltage across the second electrodes.
Claim 3
Dependent Claim
19 words
An infrared thermal detector as claimed in Claim 1, characterized in that the load resistor is a variable resistor.
Claim 4
Dependent Claim
47 words
An infrared thermal detector as claimed in Claim 2, characterized in that at the average equilibrium temperature of operation of the sensing element the ratio, k, of the thermal time constant of the sensing element to the PTB time constant of the detector is greater than zero.
Claim 5
Dependent Claim
15 words
An infrared thermal detector as claimed in Claim 3, characterized in that 0.1≤ k ≤5.
Claim 6
Dependent Claim
18 words
An infrared thermal detector as claimed in Claim 4, characterized in that k is approximately equal to 1.
Claim 7
Dependent Claim
33 words
An infrared thermal detector as claimed in Claim 5, characterized in that the sensing element has a pyroelectric axis, and the electrodes on the sensing element are substantially perpendicular to the pyroelectric axis.
Claim 8
Dependent Claim
76 words
An infrared thermal detector comprising: aninfrared thermal sensing element comprising a pyroelectric material whose electrical conductivity changes with temperature, said sensing element having two substantially planar opposite sides on which first and second electrodes are provided, respectively; a variable load resistor having first and second electrodes, the first electrode of the load resistor being electrically connected to the first electrode of the sensing element; and voltage supply means for providing a voltage across the second electrode.
Claim 9
Dependent Claim
76 words
An infrared thermal detector comprising: aninfrared thermal sensing element comprising a pyroelectric material whose electrical conductivity changes with temperature, said sensing element having two substantially planar opposite sides on which first and second electrodes are provided, respectively; a variable load resistor having first and second electrodes, the first electrode of the load resistor being electrically connected to the first electrode of the sensing element; and voltage supply means for providing a voltage across the second electrode.
Claim 10
Dependent Claim
47 words
An infrared thermal detector as claimed in Claim 7, characterized in that at the average equilibrium temperature of operation of the sensing element the ratio, k, of the thermal time constant of the sensing element to the PTB time constant of the detector is greater than zero.
Claim 11
Dependent Claim
17 words
An infrared thermal detector as claimed in Claim 8, characterized in that 0.1 < k < 5.
Claim 12
Dependent Claim
18 words
An infrared thermal detector as claimed in Claim 9, characterized in that k is approximately equal to 1.
Claim 13
Dependent Claim
33 words
An infrared thermal detector as claimed in Claim 10, characterized in that the sensing element has a pyroelectric axis, and the electrodes on the sensing element are substantially perpendicular to the pyroelectric axis.
Claim 14
Dependent Claim
116 words
An infrared thermal detector comprising: a infrared thermal sensing element comprising a pyroelectric material whose electrical conductivity changes with temperature, said sensing element having two substantially planar opposite sides on which first and second electrodes are provided, respectively; a load resistor having first and second electrodes, the first electrode of the load resistor being electrically connected to the first electrode of the sensing element; and voltage supply means for providing a voltage across the second electrode, characterized in that: at the average equilibrium temperature of operation of the sensing element the ratio, k, of the thermal time constant of the sensing element to the PTB time con- s tant of the detector is greater than zero.
Claim 15
Dependent Claim
116 words
An infrared thermal detector comprising: a infrared thermal sensing element comprising a pyroelectric material whose electrical conductivity changes with temperature, said sensing element having two substantially planar opposite sides on which first and second electrodes are provided, respectively; a load resistor having first and second electrodes, the first electrode of the load resistor being electrically connected to the first electrode of the sensing element; and voltage supply means for providing a voltage across the second electrode, characterized in that: at the average equilibrium temperature of operation of the sensing element the ratio, k, of the thermal time constant of the sensing element to the PTB time con- s tant of the detector is greater than zero.
Claim 16
Dependent Claim
89 words
13 . An infrared thermal detector as claimed in Claim 12, characterized in that: the thermal sensing element has a spontaneous polarization substantially in a given direction, said spontaneous polarization decreasing as the temperature of the sensor increases; the thermal sensing element has a temperature coefficient of resistance; the voltage supply means generates an electric field across the thermal sensing element and; the electric field across the thermal sensing element has a component in the direction of spontaneous polarization multiplied by the sign of the temperature coefficient of resistance.
Claim 17
Dependent Claim
19 words
1 4. An infrared thermal detector as claimed in Claim 13, characterized in that 0.1 < k < 5.
Claim 18
Dependent Claim
18 words
An infrared thermal detector as claimed in Claim 14, characterized in that k is approximately equal to 1.
Claim 19
Dependent Claim
35 words
An infrared thermal detector as claimed in Claim 15, characterized in that the sensing element has a pyroelectric axis, and the electrodes on the sensing element are substantially perpendicular to the pyro- elec tric axis.
Claim 20
Dependent Claim
87 words
An infrared thermal detector as claimed in Claim 12, characterized in that: the thermal sensing element has a pyroelectric coefficient, a temperature coefficient of resistance, and a spontaneous polarization, said polarization being substantially in a given direction; the voltage supply means generates an electric field across the thermal sensing element; and the electric field across the thermal sensing element has a component in the direction of the spontaneous polarization multiplied by the sign of the temperature coefficient of resistance multiplied by the sign of the pyroelectric coefficient.
References Cited (Backward Citations)
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