Method for correcting eclipse or darkle
View Patent ↗A CMOS image sensor includes a plurality of pixels arranged column and rows in an array; a column circuit for storing reset values and a value after integration; a correlated double sampler which derives an image signal from the reset and the value after integration; and an anti-eclipse circuit physically separately from the column circuit and electrically connected to one or shared between multiple columns of pixels for restoring corrupted column voltage on a column of pixels.
1. A CMOS image sensor comprising:
(a) a plurality of pixels arranged in columns and rows in an array;
(b) a column circuit for storing reset signal levels and sample image signals after integration;
(c) a correlated double sampler which derives an image signal from the reset signal levels and the sample image signals after integration;
(d) an anti-eclipse circuit physically separated from the column circuit and electrically connected to one or shared between multiple columns of pixels for detecting when a reset signal level on a column of pixels falls below a preset threshold during a reset operation and for restoring the reset signal level on the respective one or multiple columns of pixels, wherein the anti-eclipse circuit comprises
a comparator connected to one or more column of pixels via switches for comparing a predetermined voltage to a reset signal level from one of the column of pixels;
a flip-flop connected to an output of the comparator and one or more switches connected between an output of the flip flop and the respective one or multiple columns of pixels.
2. The CMOS image sensor as in claim 1 further comprising a pinned photodiode or a photodiode as the sensing region for the pixel.
3. The CMOS image sensor as in claim 1 , wherein the anti-eclipse circuit is positioned on any side of the image sensor.
4. An imaging device comprising:
a CMOS image sensor comprising:
(a) a plurality of pixels arranged column and rows in an array;
(b) a column circuit for storing reset signal levels and sample image signals after integration;
(c) a correlated double sampler which derives an image signal from the reset signal levels and the sample image signals after integration;
(d) an anti-eclipse circuit electrically and physically separately from the column circuit and electrically connected to one or shared between multiple columns of pixels for detecting when a reset signal level on a column of pixels falls below a preset threshold during a reset operation and for restoring the reset signal level on the respective one or multiple columns of pixels, wherein the anti-eclipse circuit comprises
a comparator connected to the respective one or multiple columns of pixels via switches for comparing a predetermined voltage to a reset signal level from one of the column of pixels; and
a flip-flop connected to an output of the comparator and one or more switches connected between an output of the flip flop and the respective one or multiple columns of pixels.
5. The imaging device as in claim 4 further comprising a pinned photodiode or a photodiode as the sensing region for the pixel.
6. The imaging device as in claim 4 , wherein the anti-eclipse circuit is positioned on a side of the image sensor opposite the column circuit.
7. A CMOS image sensor comprising:
(a) a plurality of pixels arranged in columns and rows in an array;
(b) a column circuit for storing reset signal levels and sample image signals after integration;
(c) a correlated double sampler which derives an image signal from the reset signal levels and the sample image signals after integration; and
(d) an anti-eclipse circuit physically separated from the column circuit and electrically connected to one or shared between multiple columns of pixels for detecting when a reset signal level on a column of pixels falls below a preset threshold during a reset operation and for restoring the reset signal level on the respective one or multiple columns of pixels, wherein the anti-eclipse circuit comprises
a switch connected to each column line;
a comparator having two or more input lines, wherein one input line is connected to a reference voltage and at least one other input line is connected to a column of pixels when a respective switch is placed in a first position;
a flip-flop connected to an output of the comparator; and
at least one transistor having a gate connected to an output of the flip-flop.
8. The CMOS image sensor as in claim 7 , wherein the anti-eclipse circuit is positioned on any side of the image sensor.