Infrared thermometers for minimizing errors associated with ambient temperature transients
First Claim
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1. Detector means useful in a measuring instrument for responding to infrared radiation from a target to produce a temperature indicating output signal, said detector means comprising:
- first thermopile means for producing an output voltage having a first component related to the amount of infrared radiation incident on a sensing area thereof and a second component related to ambient temperature transients;
transducer means for producing an output voltage exhibiting substantially the same relationship to ambient temperature transients as said first thermopile means;
means mounting said first thermopile means and said transducer means in close physical proximity to one another whereby they will experience substantially the same ambient temperature;
means for exposing said first thermopile means sensing area to radiation from said target;
means for summing in opposition said output voltages produced by said first thermopile means and said transducer means to produce said temperature indicating signal;
said transducer means comprising a second thermopile means for producing an output voltage having a first component related to the amount of infrared radiation incident on a sensing area thereof and a second component related to ambient temperature transients; and
means for shielding said second thermopile means sensing area from radiation from said target.
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Abstract
A thermopile detector means for a temperature measuring instrument physically and electrically configured to supply an output signal which indicates target temperature substantially independent of the influence of ambient temperature changes. The detector means includes a first thermopile device exposed to radiation from the target and a transducer means, preferably a second thermopile device, shielded from the target and connected in series opposition to the first.
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Citations
14 Claims
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1. Detector means useful in a measuring instrument for responding to infrared radiation from a target to produce a temperature indicating output signal, said detector means comprising:
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first thermopile means for producing an output voltage having a first component related to the amount of infrared radiation incident on a sensing area thereof and a second component related to ambient temperature transients; transducer means for producing an output voltage exhibiting substantially the same relationship to ambient temperature transients as said first thermopile means; means mounting said first thermopile means and said transducer means in close physical proximity to one another whereby they will experience substantially the same ambient temperature; means for exposing said first thermopile means sensing area to radiation from said target; means for summing in opposition said output voltages produced by said first thermopile means and said transducer means to produce said temperature indicating signal; said transducer means comprising a second thermopile means for producing an output voltage having a first component related to the amount of infrared radiation incident on a sensing area thereof and a second component related to ambient temperature transients; and means for shielding said second thermopile means sensing area from radiation from said target.
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2. A detector useful in an infrared thermometer comprising:
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a housing having a wall enveloping a cavity and defining a window for passing infrared radiation into said cavity; first thermopile means having a sensing area and first and second terminal points for producing an output voltage between said terminal points having a first component related to the amount of radiation incident on said sensing area and a second component related to ambient temperature transients; second thermopile means having a sensing area and first and second terminal points for producing an output voltage between said terminal points having a first component related to the amount of radiation incident on said sensing area and a second component related to ambient temperature transients in the same manner as said first thermopile means second component is related to ambient temperature transients; means supporting said first thermopile means in said housing oriented so that radiation passing through said housing wall window is incident on said first thermopile means sensing area; and means supporting said second thermopile means in said housing oriented so that said sensing area thereof is shielded from said radiation passing through said housing wall window.
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3. Detector means useful in a measuring instrument for responding to infrared radiation from a target to produce a temperature indicating output signal, said detector means comprising:
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first thermopile means for producing an output voltage having a first component related to the amount of infrared radiation incident on a sensing area thereof and a second component related to ambient temperature transients; second thermopile means for producing an output voltage having a component exhibiting substantially the same relationship to ambient temperature transients as said first thermpile means second component; means mounting said first and second thermopile means in close physical proximity to one another whereby they will experience substantially the same ambient temperature; means for exposing said first thermopile means sensing area to radiation form said target; means for shielding said second thermopile means sensing area from radiation from said target; and means for summing in opposition said output voltages produced by said first and second thermopile means to produce said temperature indicating signal. - View Dependent Claims (4, 5)
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6. A detector useful in an infrared thermometer comprising:
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a housing having a wall enveloping a cavity and defining a window for passing infrared radiation into said cavity; a first sheet of insulating material; first thermopile means carried by said first sheet having a sensing area and first and second terminal points for producing an output voltage between said terminal points having a first component related to the amount of radiation incident on said sensing area and a second component related to ambient temperature transients; a second sheet of insulating material; second thermopile means carried by said second sheet having a sensing area and first and second terminal points for producing an output voltage between said terminal points having a first component related to the amount of radiation incident on said sensing area and a second component related to ambient temperature transients in the same manner as said first thermopile means second component is related to ambient temperature transients; means supporting said first sheet in said housing for orienting said first thermopile means so that radiation passing through said housing wall window is incident on said first thermopile means sensing area; and means supporting said second sheet in said housing for shielding said second thermopile means sensing area from said radiation passing through said housing wall window. - View Dependent Claims (7, 8, 9, 10, 11)
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12. An instrument for measuring and displaying the temperature of a remote target, said instrument comprising:
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an instrument housing; a detector means mounted in said housing, said detector means comprising; first thermopile means for producing an output voltage related both to the amount of infrared radiation incident on a sensing area thereof and to ambient temperature transients; second thermopile means for producing an output voltage related both to the amount of infrared radiation incident on a sensing area thereof and to ambient temperature transients in the same manner as said first thermopile means; means mounting said first and second thermopile means in close physical proximity to one another whereby they will experience substantially the same ambient temperature; means for exposing said first thermopile means sensing area to radiation from said target; means for shielding said second thermopile means sensing area from radiation from said target; means for summing in opposition said output voltages produced by said first and second thermopile means to produce a temperature indicating signal; and means responsive to said temperature indicating signal for displaying the temperature of said target. - View Dependent Claims (13, 14)
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Specification