US5025318A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Imaging apparatus with means for cancelling differential offset voltage
Assignee: NEC Space Technologies Ltd
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Filing: 1989-12-27
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Granted: 1991-06-18
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Expires: 2009-12-27
Abstract
Abstract In an imaging apparatus, bipolar clock pulses are generated for driving the odd-and-even-number second shift registers of a linear charge transfer device. A voltage representing the difference between offset voltages generated respectively by the shift registers is generated by a band-pass filter or a differential circuit and multiplied with the bipolar clock pulses to produce a varying voltage of a particular polarity determined by the relative value of the offset voltages. The varying voltage is smoothed into a DC voltage by a low-pass filter. The DC voltage of appropriate polarity is combined with one of the output signals of the shift registers so that the difference between the offset voltages substantially reduces to zero through a feedback loop.
Inventors
- 👤 Riichi Nagura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 22:32
CPC Classifications
H; H04; H04N; H04N25/00; H04N25/60; H04N25/67; H04N25/671; H04N25/672; H04N25/70; H04N25/701
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
152 words
A difference voltage canceller for a charge transfer device having a photosensor divided into odd- and even-numbered photosensitive elements, a first shift register connected to the odd-numbered photosensitive elements, and a second shift register connected to the even-numbered photosensitive elements, comprising: means for generating bipolar clock pulses for driving said first and second shift registers; detector means for generating a difference voltage representative of a difference between first and second offset voltages generated respectively by said first and second shift registers; multiplier means for multiplying said difference voltage with said bipolar clock pulses; filter means for smoothing a voltage output of said multiplier means; and means for combining a voltage output of said filter means with one of the output signals of said first and second shift registers depending on the polarity of the voltage output of said filter means so that the difference between said offset voltages substantially reduces to zero.
Claim 2
Dependent Claim
152 words
A difference voltage canceller for a charge transfer device having a photosensor divided into odd- and even-numbered photosensitive elements, a first shift register connected to the odd-numbered photosensitive elements, and a second shift register connected to the even-numbered photosensitive elements, comprising: means for generating bipolar clock pulses for driving said first and second shift registers; detector means for generating a difference voltage representative of a difference between first and second offset voltages generated respectively by said first and second shift registers; multiplier means for multiplying said difference voltage with said bipolar clock pulses; filter means for smoothing a voltage output of said multiplier means; and means for combining a voltage output of said filter means with one of the output signals of said first and second shift registers depending on the polarity of the voltage output of said filter means so that the difference between said offset voltages substantially reduces to zero.
Claim 3
Dependent Claim
172 words
A difference voltage canceller for a transfer device having a photosensor divided into odd- and even-numbered photosensitive elements, a first shift register connected to the odd-numbered photosensitive elements, and a second shift register connected to the even-numbered photosensitive elements, comprising: means for generating bipolar clock pulses for driving said first and second shift registers; multiplexer means for multiplexing the output signals of said shift registers; detector means responsive to an output signal from said multiplexer means for generating therefrom a difference voltage representative of a difference between first and second offset voltages generated respectively by said first and second shift registers; multiplier means for multiplying said difference voltage with said bipolar clock pulses; filter means for smoothing a voltage output of said multiplier means; and means for combining a voltage output of said filter means with one of the output signals of said first and second shift registers depending on the polarity of the voltage output of said filter means so that the difference between said offset voltages substantially reduces to zero.
Claim 4
Dependent Claim
172 words
A difference voltage canceller for a transfer device having a photosensor divided into odd- and even-numbered photosensitive elements, a first shift register connected to the odd-numbered photosensitive elements, and a second shift register connected to the even-numbered photosensitive elements, comprising: means for generating bipolar clock pulses for driving said first and second shift registers; multiplexer means for multiplexing the output signals of said shift registers; detector means responsive to an output signal from said multiplexer means for generating therefrom a difference voltage representative of a difference between first and second offset voltages generated respectively by said first and second shift registers; multiplier means for multiplying said difference voltage with said bipolar clock pulses; filter means for smoothing a voltage output of said multiplier means; and means for combining a voltage output of said filter means with one of the output signals of said first and second shift registers depending on the polarity of the voltage output of said filter means so that the difference between said offset voltages substantially reduces to zero.
Claim 5
Dependent Claim
30 words
A difference voltage canceller as claimed in claim 2, wherein said detector means comprises band-pass filter means having a frequency band centered at the repetition frequency of said clock pulses.
Claim 6
Dependent Claim
48 words
A difference voltage canceller as claimed in claim 2, wherein said detector means comprises: delay means for delaying an output signal of said multiplexer means by one pixel interval; and subtractor means for generating said difference voltage from the outputs of said delay means and said multiplexer means.
Claim 7
Dependent Claim
92 words
A difference voltage canceller as claimed in claim 2, wherein said combining means comprises: inverter means for inverting the polarity of the voltage output of said filter means; first and second diodes connected respectively to the outputs of said inverter means and said filter means for passing voltages of specified polarity; means for subtractively combining the voltage passed through said first diode with the output voltage of said first shift register; and means for subtractively combining the voltage passed through said second diode with the output voltage of said second shift register.
Claim 8
Dependent Claim
174 words
A difference voltage canceller for a charge transfer device having a photosensor divided into odd- and even-numbered photosensitive elements, a first shift register connected to the odd-numbered photosensitive elements, a second shift register connected to the even-numbered photosensitive elements, and a multiplexer for multiplexing output signals from said first and second shift registers, comprising: means for generating bipolar clock pulses for driving said first and second shift registers; detector means responsive to an output signal from said multiplexer for generating therefrom a difference voltage representative of a difference between first and second offset voltages generated respectively by said first and second shift registers; multiplier means for multiplying said difference voltage with said bipolar clock pulses; filter means for smoothing a voltage output of said multiplier means; and means for combining a voltage output of said filter means with one of the output signals of said first and second shift registers depending on the polarity of the voltage output of said filter means so that the difference between said offset voltages substantially reduces to zero.
Claim 9
Dependent Claim
174 words
A difference voltage canceller for a charge transfer device having a photosensor divided into odd- and even-numbered photosensitive elements, a first shift register connected to the odd-numbered photosensitive elements, a second shift register connected to the even-numbered photosensitive elements, and a multiplexer for multiplexing output signals from said first and second shift registers, comprising: means for generating bipolar clock pulses for driving said first and second shift registers; detector means responsive to an output signal from said multiplexer for generating therefrom a difference voltage representative of a difference between first and second offset voltages generated respectively by said first and second shift registers; multiplier means for multiplying said difference voltage with said bipolar clock pulses; filter means for smoothing a voltage output of said multiplier means; and means for combining a voltage output of said filter means with one of the output signals of said first and second shift registers depending on the polarity of the voltage output of said filter means so that the difference between said offset voltages substantially reduces to zero.
Claim 10
Dependent Claim
30 words
A difference voltage canceller as claimed in claim 6, wherein said detector means comprises band-pass filter means having a frequency band centered at the repetition frequency of said clock pulses.
Claim 11
Dependent Claim
82 words
A difference voltage canceller as claimed in claim 6, wherein said combining means comprises: inverter means for inverting the polarity of the voltage output of said filter means; second multiplier means for multiplying the voltage output of said filter means with said bipolar clock pulses; a diode connected to the output of said second multiplier means for passing a voltage of specified polarity; and means for subtractively combining the voltage passed through said diode with the output voltage of said multiplexer means.
Claim 12
Dependent Claim
151 words
An image sensing apparatus comprising: a charge transfer device having a photosensor divided into odd- and even-numbered photosensitive elements, a first shift register connected to the odd-numbered photosensitive elements, and a second shift register connected to the even-numbered photosensitive elements; means for generating bipolar clock pulses for driving said first and second shift registers; detector means for generating a difference voltage representative of a difference between first and second offset voltages generated respectively by said first and second shift registers; multiplier means for multiplying said difference voltage with said bipolar clock pulses; filter means for smoothing a voltage output of said multiplier means; and means for combining a voltage output of said filter means with one of the output signals of said first and second shift registers depending on the polarity of the voltage output of said filter means so that the difference between said offset voltages substantially reduces to zero.
Claim 13
Dependent Claim
151 words
An image sensing apparatus comprising: a charge transfer device having a photosensor divided into odd- and even-numbered photosensitive elements, a first shift register connected to the odd-numbered photosensitive elements, and a second shift register connected to the even-numbered photosensitive elements; means for generating bipolar clock pulses for driving said first and second shift registers; detector means for generating a difference voltage representative of a difference between first and second offset voltages generated respectively by said first and second shift registers; multiplier means for multiplying said difference voltage with said bipolar clock pulses; filter means for smoothing a voltage output of said multiplier means; and means for combining a voltage output of said filter means with one of the output signals of said first and second shift registers depending on the polarity of the voltage output of said filter means so that the difference between said offset voltages substantially reduces to zero.
Claim 14
Dependent Claim
51 words
An image sensing apparatus as claimed in claim 9, wherein said detector means comprises: multiplexer means for multiplexing the output signals of said shift registers; and band-pass filter means connected to said multiplexer means, said band-pass filter means having a frequency band centered at the repetition frequency of said clock pulses.
Claim 15
Dependent Claim
172 words
An image sensing apparatus comprising: a charge transfer device having a photosensor divided into odd- and even-numbered photosensitive elements, a first shift register connected to the odd-numbered photosensitive elements, and a second shift register connected to the even-numbered photosensitive elements; means for generating bipolar clock pulses for driving said first and second shift registers; multiplexer means for multiplexing the output signals of said shift registers; detector means responsive to an output signal from said multiplexer means for generating therefrom a difference voltage representative of a difference between first and second offset voltages generated respectively by said first and second shift registers; multiplier means for multiplying said difference voltage with said bipolar clock pulses; filter means for smoothing a voltage output of said multiplier means; and means for combining a voltage output of said filter means with one of the output signals of said first and second shift registers depending on the polarity of the voltage output of said filter means so that the difference between said offset voltages substantially reduces to zero.
Claim 16
Dependent Claim
172 words
An image sensing apparatus comprising: a charge transfer device having a photosensor divided into odd- and even-numbered photosensitive elements, a first shift register connected to the odd-numbered photosensitive elements, and a second shift register connected to the even-numbered photosensitive elements; means for generating bipolar clock pulses for driving said first and second shift registers; multiplexer means for multiplexing the output signals of said shift registers; detector means responsive to an output signal from said multiplexer means for generating therefrom a difference voltage representative of a difference between first and second offset voltages generated respectively by said first and second shift registers; multiplier means for multiplying said difference voltage with said bipolar clock pulses; filter means for smoothing a voltage output of said multiplier means; and means for combining a voltage output of said filter means with one of the output signals of said first and second shift registers depending on the polarity of the voltage output of said filter means so that the difference between said offset voltages substantially reduces to zero.
Claim 17
Dependent Claim
30 words
An image sensing apparatus as claimed in claim 11, wherein said detector means comprises band-pass filter means having a frequency band centered at the repetition frequency of said clock pulses.
Claim 18
Dependent Claim
48 words
An image sensing apparatus as claimed in claim 11, wherein said detector means comprises: delay means for delaying an output signal of said multiplexer means by one pixel interval; and subtractor means for generating said difference voltage from the outputs of said delay means and said multiplexer means.
Claim 19
Dependent Claim
92 words
An image sensing apparatus as claimed in claim 11, wherein said combining means comprises: inverter means for inverting the polarity of the voltage output of said filter means; first and second diodes connected respectively to the outputs of said inverter means and said filter means for passing voltages of specified polarity; means for subtractively combining the voltage passed through said first diode with the output voltage of said first shift register; and means for subtractively combining the voltage passed through said second diode with the output voltage of said second shift register.
Claim 20
Dependent Claim
173 words
An image sensing apparatus comprising: a charge transfer device having a photosensor divided into odd- and even-numbered photosensitive elements, a first shift register connected to the odd-numbered photosensitive elements, a second shift register connected to the even-numbered photosensitive elements, and a multiplexer for multiplexing output signals from said first and second shift registers; means for generating bipolar clock pulses for driving said first and second shift registers; detector means responsive to an output signal from said multiplexer for generating therefrom a difference voltage representative of a difference between first and second offset voltages generated respectively by said first and second shift registers; multiplier means for multiplying said difference voltage with said bipolar clock pulses; filter means for smoothing a voltage output of said multiplier means; and means for combining a voltage output of said filter means with one of the output signals of said first and second shift registers depending on the polarity of the voltage output of said filter means so that the difference between said offset voltages substantially reduces to zero.
Claim 21
Dependent Claim
173 words
An image sensing apparatus comprising: a charge transfer device having a photosensor divided into odd- and even-numbered photosensitive elements, a first shift register connected to the odd-numbered photosensitive elements, a second shift register connected to the even-numbered photosensitive elements, and a multiplexer for multiplexing output signals from said first and second shift registers; means for generating bipolar clock pulses for driving said first and second shift registers; detector means responsive to an output signal from said multiplexer for generating therefrom a difference voltage representative of a difference between first and second offset voltages generated respectively by said first and second shift registers; multiplier means for multiplying said difference voltage with said bipolar clock pulses; filter means for smoothing a voltage output of said multiplier means; and means for combining a voltage output of said filter means with one of the output signals of said first and second shift registers depending on the polarity of the voltage output of said filter means so that the difference between said offset voltages substantially reduces to zero.
Claim 22
Dependent Claim
30 words
An image sensing apparatus as claimed in claim 15, wherein said detector means comprises band-pass filter means having a frequency band centered at the repetition frequency of said clock pulses.
Claim 23
Dependent Claim
82 words
An image sensing apparatus as claimed in claim 15, wherein said combining means comprises: inverter means for inverting the polarity of the voltage output of said filter means; second multiplier means for multiplying the voltage output of said filter means with said bipolar clock pulses; a diode connected to the output of said second multiplier means for passing a voltage of specified polarity; and means for subtractively combining the voltage passed through said diode with the output voltage of said multiplexer means.
Claim 24
Independent Claim
153 words
A method for cancelling the difference between offset voltages generated by first and second shift registers of a charge transfer device, said first and second shift registers being coupled respectively to odd- and even-numbered photosensitive resolution elements, comprising the steps of: (a) generating bipolar clock pulses and driving said first and second shift registers with the clock pulses to transfer charges photogenerated by said resolution elements along said first and second shift registers; (b) generating a difference voltage representing the difference between said offset voltages; (c) multiplying said difference voltage with the bipolar clock pulses to produce a varying voltage of a particular polarity depending on the relative value of said offset voltages; (d) low-pass filtering said varying voltage; and (e) combining the low-pass filtered voltage of appropriate polarity with one of output voltages from said first and second shift registers so that the difference between said offset voltages substantially reduces to zero.
Claim 25
Independent Claim
153 words
A method for cancelling the difference between offset voltages generated by first and second shift registers of a charge transfer device, said first and second shift registers being coupled respectively to odd- and even-numbered photosensitive resolution elements, comprising the steps of: (a) generating bipolar clock pulses and driving said first and second shift registers with the clock pulses to transfer charges photogenerated by said resolution elements along said first and second shift registers; (b) generating a difference voltage representing the difference between said offset voltages; (c) multiplying said difference voltage with the bipolar clock pulses to produce a varying voltage of a particular polarity depending on the relative value of said offset voltages; (d) low-pass filtering said varying voltage; and (e) combining the low-pass filtered voltage of appropriate polarity with one of output voltages from said first and second shift registers so that the difference between said offset voltages substantially reduces to zero.
References Cited (Backward Citations)
US4307423A
Cited
US4710816A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-06-17 | 1994-12-17 | 1995-06-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-06-17 | 1998-12-17 | 1999-06-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-06-17 | 2002-12-17 | 2003-06-18 | $7700.00 | Window Closed / Lapsed |