Patent US3766781A successfully refreshed from Google Patents.
US3766781A
Expired / Lapsed
US
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Apparatus for temperature measurement
Assignee: ZF International UK Ltd
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Filing: 1971-03-29
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Granted: 1973-10-23
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Expires: 1991-03-29
Abstract
Abstract An apparatus for measuring the temperature of an infra-red source includes provision for modulating the output of an infrared sensitive device and for generating a signal in synchronism with peaks of the modulated output, said signal being used to control a switch so as to provide a d.c. signal porportional to the levels of said peaks. A circuit, which generates a function which is the inverse of the relationship between the source temperature and the d.c. signal, provides an output for the apparatus which has a linear relationship with the temperature.
Inventors
- 👤 T Roberts
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 20:30
CPC Classifications
G; G01; G01K; G01K1/00; G01K1/20; G01J; G01J5/00; G01J5/02; G01J5/08; G01J5/0803; G01J5/0805
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
126 words
An apparatus for temperature measurement comprising a means sensitive to infra-red radiation and adapted to provide a voltage signal whose magnitude is dependent on the level of said radiation, an occulting shutter between said infra-red sensitive means and an associated source of infra-red radiation, whereby said voltage signal comprises an alternating signal, a demodulator for said alternating signal, said demodulator generating a train of pulses which are substantially in synchronism with the peaks of said alternating signal, said demodulator including a pulse shaping circuit and a monostable multivibrator, switching means for the alternating signal operable by each of said pulses, and linearising means operable by the demodulated signals to provide an output which is linearly dependent on the temperature of a substance providing the infrared radiation.
Claim 2
Independent Claim
126 words
An apparatus for temperature measurement comprising a means sensitive to infra-red radiation and adapted to provide a voltage signal whose magnitude is dependent on the level of said radiation, an occulting shutter between said infra-red sensitive means and an associated source of infra-red radiation, whereby said voltage signal comprises an alternating signal, a demodulator for said alternating signal, said demodulator generating a train of pulses which are substantially in synchronism with the peaks of said alternating signal, said demodulator including a pulse shaping circuit and a monostable multivibrator, switching means for the alternating signal operable by each of said pulses, and linearising means operable by the demodulated signals to provide an output which is linearly dependent on the temperature of a substance providing the infrared radiation.
Claim 3
Dependent Claim
20 words
An apparatus as claimed in claim 1 in which said means sensitive to infra red radiation is a photo-resistive device.
Claim 4
Dependent Claim
27 words
An apparatus as claimed in claim 1 in which said shutter comprises a disc formed with equi-spaced circumferential apertures, and which includes means for rotating said disc.
Claim 5
Dependent Claim
27 words
An apparatus as claimed in claim 3 in which said apertures are formed so as to provide a mark-space ratio of one to one for the shutter.
Claim 6
Dependent Claim
29 words
An apparatus as claimed in claim 1 in which said demodulator further includes a light source, a photo-resistive device and a shutter between said source and said photo-resistive device.
Claim 7
Dependent Claim
29 words
An apparatus as claimed in claim 5 in which said shutter between said source and said photoresistive device is constituted by the shutter associated with said infra-red sensitive means.
Claim 8
Dependent Claim
17 words
An apparatus as claimed in claim 5 in which the light source is a gallium arsenide diode.
Claim 9
Dependent Claim
42 words
An apparatus as clAimed in claim 1 in which said linearising means comprises a circuit for generating a function which is the inverse of the relationship between the temperature to be measured and the voltage signal provided by said infrared sensitive means.
Claim 10
Dependent Claim
25 words
An apparatus as claimed in claim 1 which includes a metal block with which said infra-red sensitive means and said shutter are in thermal contact.
Claim 11
Dependent Claim
15 words
An apparatus as claimed in claim 9 which includes temperature control arrangement for said block.
Claim 12
Dependent Claim
44 words
An apparatus as claimed in claim 10 in which said temperature control arrangement includes a Peltier effect device in thermal contact with said block and switching means responsive to the temperature of said block for regulation a current supply of said Peltier effect device.
Claim 13
Independent Claim
214 words
An apparatus for temperature measurement comprising means sensitive to infra-red radiation and adapted to provide a voltage signal whose magnitude is dependent on the level of said radiation, means for modulating the impingement of said radiation on said radiation sensitive means, whereby said voltage signal is an alternating signal, a demodulator for said alternating signal, said demodulator comprising means for generating a train of pulses which are substantially in synchronism with the peaks of said alternating signal, switching means for the alternating signal operable by each of said pulses, linearising means operable by the demodulated signal to provide an output which is linearly dependant on the temperature of a substance providing the infra-red radiation, and a thermocouple disposed to sense the temperature of said substance to provide a first current signal which changes with a known time constant for a given change in said temperature, the apparatus also including means responsive to the output of said linearising means to provide, in response to said temperature change, a second current signal initially substantially equal in magnitude to the magnitude of the first current signal after said change, said second current signal decaying to zero with a time constant substantially equal to that of said thermocouple, and means for summing the first and second current signals.
Claim 14
Independent Claim
214 words
An apparatus for temperature measurement comprising means sensitive to infra-red radiation and adapted to provide a voltage signal whose magnitude is dependent on the level of said radiation, means for modulating the impingement of said radiation on said radiation sensitive means, whereby said voltage signal is an alternating signal, a demodulator for said alternating signal, said demodulator comprising means for generating a train of pulses which are substantially in synchronism with the peaks of said alternating signal, switching means for the alternating signal operable by each of said pulses, linearising means operable by the demodulated signal to provide an output which is linearly dependant on the temperature of a substance providing the infra-red radiation, and a thermocouple disposed to sense the temperature of said substance to provide a first current signal which changes with a known time constant for a given change in said temperature, the apparatus also including means responsive to the output of said linearising means to provide, in response to said temperature change, a second current signal initially substantially equal in magnitude to the magnitude of the first current signal after said change, said second current signal decaying to zero with a time constant substantially equal to that of said thermocouple, and means for summing the first and second current signals.
Claim 15
Dependent Claim
35 words
An apparatus as claimed in claim 12 in which said means responsive to the output of the linearising means comprises a resistance and capacitance arrangement having a time constant equal to that of said thermocouple.
Claim 16
Dependent Claim
15 words
An apparatus as claimed in claim 12 in which said summing means is an amplifier.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-10-22 | 1977-04-23 | 1977-10-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-10-22 | 1981-04-23 | 1981-10-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-10-22 | 1985-04-23 | 1985-10-23 | $7700.00 | Window Closed / Lapsed |