Patent US5489776A successfully refreshed from Google Patents.
US5489776A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Microbolometer unit cell signal processing circuit
Assignee: OL Security LLC
•
Filing: 1994-08-30
•
Granted: 1996-02-06
•
Expires: 2014-08-30
Abstract
Abstract A circuit (30) for processing a signal provided by a silicon microbolometer unit cell (76). In accordance with the invention, electrical energy is applied to a first terminal of the unit cell (76) to generate first and second signals at the first terminal thereof during first and second time intervals or fields, respectively. These signals are sampled and subtracted from each other by a sampling capacitor (80) to provide a third signal which is directly proportional to a difference between the first signal and the second sampled signal. In a specific embodiment, the difference signal is amplified to provide the desired output signal. The inventive circuit provides coarse DC offset non-uniformity correction and sets the overall gain of a focal plane array of silicon microbolometer unit cell detectors. This allows for use of a simplified analog signal processing circuit.
Inventors
- 👤 Gerald Lung
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 19:57
CPC Classifications
G; G01; G01J; G01J5/00; G01J5/10; G01J5/20; G01J5/22; G01J5/24; H; H04; H04N; H04N23/00; H04N23/20; H04N23/23; H04N25/00; H04N25/20; H04N25/21; H04N25/60; H04N25/67; H04N25/671; H04N25/70; H04N25/76
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
165 words
A circuit for processing a signal provided by a microbolometer unit cell comprising: first means for selectively applying electrical energy to a first terminal of the unit cell to generate first and second signals at the first terminal thereof during first and second time intervals, said first means including a current source and a first switch for selectively connecting the current source to the first terminal of the unit cell; second means for sampling the first signal during the first time interval and for sampling the second signal during the second time interval to provide first and second sampled signals respectively, said second means including a second switch having a first terminal connected to the first terminal of the unit cell; and third means for providing a third signal which is directly proportional to a difference between the first sampled signal and the second sampled signal, said third means including a capacitor having a first terminal connected to a second terminal of the second switch.
Claim 2
Dependent Claim
165 words
A circuit for processing a signal provided by a microbolometer unit cell comprising: first means for selectively applying electrical energy to a first terminal of the unit cell to generate first and second signals at the first terminal thereof during first and second time intervals, said first means including a current source and a first switch for selectively connecting the current source to the first terminal of the unit cell; second means for sampling the first signal during the first time interval and for sampling the second signal during the second time interval to provide first and second sampled signals respectively, said second means including a second switch having a first terminal connected to the first terminal of the unit cell; and third means for providing a third signal which is directly proportional to a difference between the first sampled signal and the second sampled signal, said third means including a capacitor having a first terminal connected to a second terminal of the second switch.
Claim 3
Dependent Claim
23 words
The invention of claim 1 further including fourth means for amplifying the difference between the first sampled signal and the second sampled signal.
Claim 4
Dependent Claim
30 words
The invention of claim 2 wherein the fourth means includes an amplifier, and wherein a second terminal of the capacitor is connected to a first input terminal of the amplifier.
Claim 5
Dependent Claim
24 words
The invention of claim 3 further including a third switch connected across an output terminal of the amplifier and the first input terminal thereof.
Claim 6
Dependent Claim
24 words
The invention of claim 4 further including a second capacitor connected across the output terminal of the amplifier and the first input terminal thereof.
Claim 7
Dependent Claim
24 words
The invention of claim 3 further including fifth means for selectively connecting a noise limiting element to the first terminal of the unit cell.
Claim 8
Dependent Claim
26 words
The invention of claim 6 wherein the third means includes a fourth switch for connecting a third capacitor to the first terminal of the unit cell.
Claim 9
Dependent Claim
46 words
The invention of claim 7 further including means for selectively controlling the first, second, and third switches to sample the signals at the first terminal of the unit cell during consecutive fields to create a field to field difference signal for amplification by the and amplifier.
Claim 10
Dependent Claim
180 words
A night vision camera comprising: an array of microbolometer unit cells; a plurality of unit cell signal processing circuits, one for each unit cell, each circuit including: a current source, a first switch for coupling said current source to a first terminal of an associated unit cell to generate first and second signals at the first terminal thereof during first and second time intervals, sampling means for sampling the first signal during the first time interval and for sampling the second signal during the second time interval to provide first and second sampled signals respectively, said sampling means including a second switch having a first terminal connected to the first terminal of the unit cell, means providing a third signal which is directly proportional to a difference between the first sampled signal and the second sampled signal, said means including a capacitor having a first terminal connected to a second terminal of the second switch, and amplifying means for amplifying the difference between the first sampled signal and the second sampled signal; and means for displaying the amplified difference signals.
Claim 11
Dependent Claim
180 words
A night vision camera comprising: an array of microbolometer unit cells; a plurality of unit cell signal processing circuits, one for each unit cell, each circuit including: a current source, a first switch for coupling said current source to a first terminal of an associated unit cell to generate first and second signals at the first terminal thereof during first and second time intervals, sampling means for sampling the first signal during the first time interval and for sampling the second signal during the second time interval to provide first and second sampled signals respectively, said sampling means including a second switch having a first terminal connected to the first terminal of the unit cell, means providing a third signal which is directly proportional to a difference between the first sampled signal and the second sampled signal, said means including a capacitor having a first terminal connected to a second terminal of the second switch, and amplifying means for amplifying the difference between the first sampled signal and the second sampled signal; and means for displaying the amplified difference signals.
References Cited (Backward Citations)
US4795904A
Cited
US4902895A
Cited
US5021663A
Cited
US5021663B1
Cited
US5286976A
Cited
US5369280A
Cited
US5196703A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-02-05 | 1999-08-07 | 2000-02-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-02-05 | 2003-08-07 | 2004-02-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-02-05 | 2007-08-07 | 2008-02-06 | $7700.00 | Window Closed / Lapsed |