US5170129A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Charge detecting circuit with variable capacitor and method for same
Assignee: Fujifilm Business Innovation Corp
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Filing: 1991-09-30
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Granted: 1992-12-08
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Expires: 2011-09-30
Abstract
Abstract A method of detecting the charges which photo-electric conversion elements produce in correspondence to the density data of minute regions in an original image. In the method, a variable capacitor is charged with the capacitance set to a large value, and the voltage developed across the variable capacitor is detected with the capacitance set to a small value, whereby the voltage to be detected is increased as much, with an improvement in the signal detection accuracy.
Inventors
- 👤 Mamoru Nobue
- 👤 Kazuhiro Sakai
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 02:19
CPC Classifications
G; G01; G01R; G01R29/00; G01R29/24
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
72 words
A charge detecting circuit comprising: a variable capacitor having a capacitance adapted to be changeable by external means, wherein said variable capacitor comprises a plurality of capacitors, said plurality of capacitors being alternately connected to one another in series or in parallel to change said capacitance of said variable capacitor; injecting means for injecting a charge into said variable capacitor; and detecting means for detecting a voltage developed across said variable capacitor.
Claim 2
Dependent Claim
72 words
A charge detecting circuit comprising: a variable capacitor having a capacitance adapted to be changeable by external means, wherein said variable capacitor comprises a plurality of capacitors, said plurality of capacitors being alternately connected to one another in series or in parallel to change said capacitance of said variable capacitor; injecting means for injecting a charge into said variable capacitor; and detecting means for detecting a voltage developed across said variable capacitor.
Claim 3
Dependent Claim
22 words
A charge detecting circuit as claimed in claim 1, wherein the capacitance of said variable capacitor is changed by an external voltage.
Claim 4
Dependent Claim
24 words
A charge detecting circuit as claimed in claim 1, wherein said injecting means is connected through a switching element to a charge generating source.
Claim 5
Dependent Claim
17 words
A charge detecting circuit as claimed in claim 1, wherein said detecting means is a differential amplifier.
Claim 6
Dependent Claim
39 words
A charge detecting circuit as claimed in claim 1, wherein said variable capacitor is formed by laying a first conductor layer, an insulating layer, a semiconductor layer, and a second conductor layer one on another in the stated order.
Claim 7
Dependent Claim
56 words
A charge detecting circuit as claimed in claim 1, wherein upon series connection of said plurality of capacitors to one another, a first terminal of a first one of said plurality of capacitors is connected to ground and a second terminal of said first one of said plurality of capacitors is connected to said injecting means.
Claim 8
Dependent Claim
69 words
A charge detecting method comprising the steps of: setting a variable capacitor to a predetermined capacitance, said variable capacitor comprising a plurality of individual capacitors; establishing a charge on said variable capacitor; alternately connecting said plurality of individual capacitors in series or in parallel to change said predetermined capacitance of said variable capacitor while maintaining said charge on the variable capacitor; detecting a voltage developed across the variable capacitor.
Claim 9
Dependent Claim
69 words
A charge detecting method comprising the steps of: setting a variable capacitor to a predetermined capacitance, said variable capacitor comprising a plurality of individual capacitors; establishing a charge on said variable capacitor; alternately connecting said plurality of individual capacitors in series or in parallel to change said predetermined capacitance of said variable capacitor while maintaining said charge on the variable capacitor; detecting a voltage developed across the variable capacitor.
Claim 10
Dependent Claim
94 words
An image reading device, comprising: a plurality of photoelectric conversion elements arranged in an array, each photoelectric conversion element producing an optical charge in response to light reflected from an image; a plurality of variable capacitors, each one of said plurality of variable capacitors having a capacitance and storing the optical charge of a respective photoelectric conversion element; means for changing said capacitance of each one of said plurality of variable capacitors while maintaining the stored optical charge; and means for detecting a voltage developed across each one of said plurality of variable capacitors.
Claim 11
Dependent Claim
94 words
An image reading device, comprising: a plurality of photoelectric conversion elements arranged in an array, each photoelectric conversion element producing an optical charge in response to light reflected from an image; a plurality of variable capacitors, each one of said plurality of variable capacitors having a capacitance and storing the optical charge of a respective photoelectric conversion element; means for changing said capacitance of each one of said plurality of variable capacitors while maintaining the stored optical charge; and means for detecting a voltage developed across each one of said plurality of variable capacitors.
Claim 12
Dependent Claim
34 words
The image reading device of claim 8, wherein the means for changing includes a plurality of switches, each of said switches being interposed between a respective photoelectric conversion element and a corresponding variable capacitor.
Claim 13
Dependent Claim
26 words
The image reading device of claim 8, wherein the means for changing includes means for changing an external voltage applied to each of said variable capacitors.
Claim 14
Dependent Claim
16 words
The image reading device of claim 8 ,wherein the means for detecting includes a differential 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) | 1995-12-08 | 1996-06-08 | 1996-12-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-12-08 | 2000-06-08 | 2000-12-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-12-08 | 2004-06-08 | 2004-12-08 | $7700.00 | Window Closed / Lapsed |