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US6002432A
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Method for operating an active pixel sensor cell that reduces noise in the photo information extracted from the cell
Assignee: Foveon Inc
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Filing: 1996-09-10
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Granted: 1999-12-14
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Expires: 2016-09-10
Abstract
Abstract The noise in the photo information extracted from an active pixel sensor cell is reduced by resetting the voltage on the photodiode of the cell to the power supply voltage, and by reading the cell immediately before and after the cell is reset. The voltage on the photodiode is reset to the power supply voltage by applying a reset voltage to the gate of the reset transistor conventionally used to reset the photodiode where the reset voltage is sufficiently larger than the power supply voltage to cause the voltage on the photodiode to be pulled up to the power supply voltage.
Inventors
- 👤 Richard Billings Merrill
- 👤 Kevin E. Brehmer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 15:19
CPC Classifications
H; H04; H04N; H04N25/00; H04N25/60; H04N25/65; H04N25/617; H04N25/616; H04N25/62; H04N25/627
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
229 words
A method for operating an active pixel sensor cell that includes: a reset transistor connected to a power supply node, a first intermediate node, and a first input node, a photon collector connected to the first intermediate node, a buffer transistor connected to the power supply node, a second intermediate node, and the first intermediate node, and a row select transistor connected to the second intermediate node, a third intermediate node, and a second input node, the method comprising the steps of: applying a row select voltage to the second input node at a first time, the row select voltage causing a final integration voltage on the second intermediate node to appear on the third intermediate node; applying a reset voltage to the first input node at a second time, the second time occurring after the first time, the reset voltage setting an initial integration voltage on the second intermediate node; applying the row select voltage to the second input node at a third time, the third time occurring after the second time, the row select voltage causing the initial integration voltage on the second intermediate node to appear on the third intermediate node; and calculating a voltage difference between the initial integration voltage transferred to the third intermediate node at the third time and the final integration voltage transferred to the third intermediate node at the first time.
Claim 2
Independent Claim
229 words
A method for operating an active pixel sensor cell that includes: a reset transistor connected to a power supply node, a first intermediate node, and a first input node, a photon collector connected to the first intermediate node, a buffer transistor connected to the power supply node, a second intermediate node, and the first intermediate node, and a row select transistor connected to the second intermediate node, a third intermediate node, and a second input node, the method comprising the steps of: applying a row select voltage to the second input node at a first time, the row select voltage causing a final integration voltage on the second intermediate node to appear on the third intermediate node; applying a reset voltage to the first input node at a second time, the second time occurring after the first time, the reset voltage setting an initial integration voltage on the second intermediate node; applying the row select voltage to the second input node at a third time, the third time occurring after the second time, the row select voltage causing the initial integration voltage on the second intermediate node to appear on the third intermediate node; and calculating a voltage difference between the initial integration voltage transferred to the third intermediate node at the third time and the final integration voltage transferred to the third intermediate node at the first time.
Claim 3
Dependent Claim
17 words
The method of claim 1 wherein the initial integration voltage is greater than the final integration voltage.
Claim 4
Dependent Claim
19 words
The method of claim 2 wherein the reset voltage is greater than a voltage on the power supply node.
Claim 5
Dependent Claim
28 words
The method of claim 3 wherein the reset voltage causes the voltage on the first intermediate node to be set to the voltage on the power supply node.
Claim 6
Dependent Claim
35 words
The method of claim 4 wherein the reset transistor has a drain connected to the power supply node, a source connected to the first intermediate node, and a gate connected to the first input node.
Claim 7
Dependent Claim
12 words
The method of claim 5 wherein the photon collector is a photodiode.
Claim 8
Dependent Claim
35 words
The method of claim 6 wherein the buffer transistor has a drain connected to the power supply node, a source connected to the second intermediate node, and a gate connected to the first intermediate node.
Claim 9
Dependent Claim
35 words
The method of claim 7 wherein the row select transistor has a drain connected to the second intermediate node, a source connected to the third node, and a gate connected to the second input node.
Claim 10
Independent Claim
249 words
A method for operating an active pixel sensor cell that includes: a reset transistor connected to a power supply node, a first intermediate node, and a first input node, a photon collector connected to the first intermediate node, a buffer transistor connected to the power supply node, a second intermediate node, and the first intermediate node, and a row select transistor connected to the second intermediate node, a third intermediate node, and a second input node, the method comprising the steps of: applying a reset voltage to the first input node at a first time, the reset voltage being greater than a voltage on the power supply node and setting an initial integration voltage on the second intermediate node; applying a row select voltage to the second input node at a second time, the second time occurring after the first time, the row select voltage causing the initial integration voltage to appear on the third intermediate node; collecting photons, the collected photons causing the voltage on the second intermediate node to fall to a final integration voltage; applying the row select voltage to the second input node at a third time, the third time occurring after the second time, the row select voltage causing the final integration voltage to appear on the third intermediate node; and calculating a difference in voltage between the initial integration voltage on the third intermediate node at the second time and the final integration voltage on the third intermediate node at the third time.
Claim 11
Independent Claim
249 words
A method for operating an active pixel sensor cell that includes: a reset transistor connected to a power supply node, a first intermediate node, and a first input node, a photon collector connected to the first intermediate node, a buffer transistor connected to the power supply node, a second intermediate node, and the first intermediate node, and a row select transistor connected to the second intermediate node, a third intermediate node, and a second input node, the method comprising the steps of: applying a reset voltage to the first input node at a first time, the reset voltage being greater than a voltage on the power supply node and setting an initial integration voltage on the second intermediate node; applying a row select voltage to the second input node at a second time, the second time occurring after the first time, the row select voltage causing the initial integration voltage to appear on the third intermediate node; collecting photons, the collected photons causing the voltage on the second intermediate node to fall to a final integration voltage; applying the row select voltage to the second input node at a third time, the third time occurring after the second time, the row select voltage causing the final integration voltage to appear on the third intermediate node; and calculating a difference in voltage between the initial integration voltage on the third intermediate node at the second time and the final integration voltage on the third intermediate node at the third time.
Claim 12
Dependent Claim
17 words
The method of claim 9 wherein the initial integration voltage is greater than the final integration voltage.
Claim 13
Dependent Claim
28 words
The method of claim 10 wherein the reset voltage causes the voltage on the first intermediate node to be set to the voltage on the power supply node.
Claim 14
Dependent Claim
35 words
The method of claim 11 wherein the reset transistor has a drain connected to the power supply node, a source connected to the first intermediate node, and a gate connected to the first input node.
Claim 15
Dependent Claim
12 words
The method of claim 12 wherein the photon collector is a photodiode.
Claim 16
Dependent Claim
35 words
The method of claim 13 wherein the buffer transistor has a drain connected to the power supply node, a source connected to the second intermediate node, and a gate connected to the first intermediate node.
Claim 17
Dependent Claim
35 words
The method of claim 14 wherein the row select transistor has a drain connected to the second intermediate node, a source connected to the third node, and a gate connected to the second input node.
Claim 18
Independent Claim
251 words
A method for operating an active pixel sensor cell that includes: a reset transistor connected to a power supply node, a first intermediate node, and a first input node, a photon collector connected to the first intermediate node, a buffer transistor connected to the power supply node, a second intermediate node, and the first intermediate node, and a row select transistor connected to the second intermediate node, a third intermediate node, and a second input node, the method comprising the steps of: applying a row select voltage to the second input node at a first time, the row select voltage causing a final integration voltage on the second intermediate node to appear on the third intermediate node; storing the final integration voltage transferred to the third intermediate node at the first time as a first voltage; applying a reset voltage to the first input node at a second time, the second time occurring after the first time, the reset voltage setting an initial integration voltage on the second intermediate node; applying the row select voltage to the second input node at a third time, the third time occurring after the second time, the row select voltage causing the initial integration voltage on the second intermediate node to appear on the third intermediate node; and storing the initial integration voltage transferred to the third intermediate node at the third time as second voltage; calculating a voltage difference between the first voltage and the second voltage to determine a number of collected photons.
Claim 19
Independent Claim
251 words
A method for operating an active pixel sensor cell that includes: a reset transistor connected to a power supply node, a first intermediate node, and a first input node, a photon collector connected to the first intermediate node, a buffer transistor connected to the power supply node, a second intermediate node, and the first intermediate node, and a row select transistor connected to the second intermediate node, a third intermediate node, and a second input node, the method comprising the steps of: applying a row select voltage to the second input node at a first time, the row select voltage causing a final integration voltage on the second intermediate node to appear on the third intermediate node; storing the final integration voltage transferred to the third intermediate node at the first time as a first voltage; applying a reset voltage to the first input node at a second time, the second time occurring after the first time, the reset voltage setting an initial integration voltage on the second intermediate node; applying the row select voltage to the second input node at a third time, the third time occurring after the second time, the row select voltage causing the initial integration voltage on the second intermediate node to appear on the third intermediate node; and storing the initial integration voltage transferred to the third intermediate node at the third time as second voltage; calculating a voltage difference between the first voltage and the second voltage to determine a number of collected photons.
Claim 20
Dependent Claim
17 words
The method of claim 16 wherein the initial integration voltage is greater than the final integration voltage.
Claim 21
Dependent Claim
19 words
The method of claim 16 wherein the reset voltage is greater than a voltage on the power supply node.
Claim 22
Dependent Claim
28 words
The method of claim 18 wherein the reset voltage causes the voltage on the first intermediate node to be set to the voltage on the power supply node.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2002-12-13 | 2003-06-14 | 2003-12-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-12-13 | 2007-06-14 | 2007-12-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-12-13 | 2011-06-14 | 2011-12-14 | $7700.00 | Window Closed / Lapsed |