US5262647A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Infrared detector with pyroelectric detector element and chopper control circuit
Assignee: Murata Manufacturing Co Ltd
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Filing: 1992-10-16
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Granted: 1993-11-16
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Expires: 2012-10-16
Abstract
Abstract An infrared detector with a pyroelectric detector element and an AC amplifier has a chopper control circuit that enables the detector to sense either a moving person or temperature. When used to sense a moving person, the chopper control circuit stops operation of the chopper, and the gain of the amplifier is increased. When used to sense temperature, the chopper is operational, the gain of the amplifier is decreased, and total infrared energy is measured.
Inventors
- 👤 Akira Kumada
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 22:47
CPC Classifications
G; G08; G08B; G08B13/00; G08B13/18; G08B13/189; G08B13/19; G08B13/191
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
93 words
An IR detector having a pyroelectric infrared detector element, a chopper mechanism which cyclically interrupts an infrared ray input to the pyroelectric infrared detector element, a chopper driving circuit which drives the chopper mechanism, and an AC amplifier which amplifies an output signal from the pyroelectric infrared detector element in AC mode; characterized in that the IR detector includes a chopper control circuit which controls operation/stop of the chopper mechanism according to a control signal and a gain control circuit which changes a gain of the AC amplifier according to the control signal.
Claim 2
Dependent Claim
93 words
An IR detector having a pyroelectric infrared detector element, a chopper mechanism which cyclically interrupts an infrared ray input to the pyroelectric infrared detector element, a chopper driving circuit which drives the chopper mechanism, and an AC amplifier which amplifies an output signal from the pyroelectric infrared detector element in AC mode; characterized in that the IR detector includes a chopper control circuit which controls operation/stop of the chopper mechanism according to a control signal and a gain control circuit which changes a gain of the AC amplifier according to the control signal.
Claim 3
Dependent Claim
60 words
The IR detector of claim 1 wherein the gain control circuit decreases the gain of the AC amplifier when the control signal by which the chopper control circuit makes the chopper mechanism operate is input and increases the gain of the AC amplifier when the control signal by which the chopper control circuit makes the chopper mechanism stop is input.
Claim 4
Dependent Claim
24 words
The IR detector of claim 2 wherein the chopper control circuit comprises an oscillator which starts and stops oscillation according to the control signal.
Claim 5
Dependent Claim
18 words
The IR detector of claim 1 wherein the control signal is input from outside of the IR detector.
References Cited (Backward Citations)
US4825075A
Cited
JPH01124721A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1996-11-15 | 1997-05-17 | 1997-11-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-11-15 | 2001-05-17 | 2001-11-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-11-15 | 2005-05-17 | 2005-11-16 | $7700.00 | Window Closed / Lapsed |