Method and apparatus providing pixel storage gate charge sensing for electronic stabilization in imagers

• US 9,554,071 B2
• Filed: 06/14/2013
• Issued: 01/24/2017
• Est. Priority Date: 01/13/2006
• Status: Active Grant

• Current Assignee: Micron Technology, Inc.
• Original Assignee: Micron Technology, Inc.
• Inventors: Panicacci, Roger
• Primary Examiner(s): BUI PHO, PASCAL M
• Application Number:
  US13/917,831
• Publication Number:
  US 20130313409A1
• Time in Patent Office: 1,320 Days
• Field of Search: 348/241, 348/248, 348/296, 348/297, 348/298, 348/299, 348300-302, 348/308, 257/257, 257/258, 257290-292, 257/225, 257/229, 257/230, 250/214.SW, 250/208.1, 250/214.R, 250/214.1
• US Class Current: 1/1
• CPC Class Codes: H04N 25/40 Extracting pixel data from image sensors by controlling scanning circuits, e.g. by modifying the number of pixels sampled or to be sampled
• CPC Class Codes: H04N 25/75 Circuitry for providing, modifying or processing image signals from the pixel array
• CPC Class Codes: H04N 25/76 Addressed sensors, e.g. MOS or CMOS sensors
• CPC Class Codes: H04N 25/771 comprising storage means other than floating diffusion
• CPC Class Codes: H04N 3/155 Control of the image-sensor operation, e.g. image processing within the image-sensor

Abstract

An imaging device that stores charge from a photosensor under at least one storage gate. A driver used to operate the at least one storage gate, senses how much charge was transferred to the storage gate. The sensed charge is used to obtain at least one signature of the image scene. The at least one signature may then be used for processing such as e.g., motion detection, auto-exposure, and auto-white balancing.

Claims

1. An imager comprising:

at least one pixel, each pixel comprising;

a photosensor;

a storage node configured to store charge;

a transfer transistor configured to transfer charge to the storage node;

an output transistor configured to provide a first signal representing the charge transferred to the storage node; and

a first storage gate between the photosensor and transfer gate configured to store charge originating from the photosensor; and

a first driver and sense circuit having a storage capacitor switchably coupled to the first storage gate by at least one switch, wherein the first driver and sense circuit is configured to (1) provide a second signal that controls operation of the first storage gate to store charge originating from the photosensor, (2) sense an amount of charge driven out to the first storage gate while concurrently providing the second signal, and (3) store charge via the storage capacitor and the at least one switch corresponding to the amount of sensed charge, wherein the second signal is different than the first signal.

2. An imager as in claim 1, wherein said at least one pixel comprises a plurality of pixels arranged in a first pixel set;

and

wherein the first driver and sense circuit is associated with the first storage gates of the pixels in the first pixel set and is configured to control operation of the first storage gates of the pixels in the first pixel set to store charge from a respective photosensor and provide a signal having a component representing the charge stored by all of the first storage gates of the first pixel set.

3. An imager as in claim 2, wherein the first driver and sense circuit is part of a row driver circuit for a first set of pixels in a row of a pixel array.

4. An imager as in claim 2, wherein the first driver and sense circuit is part of a column driver circuit for a first set of pixels in a column of a pixel array.

5. An imager as in claim 2, further comprising a plurality of pixels arranged in a second pixel set, each pixel of the second pixel set further comprising a second storage gate configured to store charge originating at a respective photosensor, the imager further comprising a second driver and sense circuit associated with the second storage gates, the second driver and sense circuit configured to control operation of the second storage gates and provide a signal having a component representing the charge stored by all of the second storage gates of the second pixel set.

6. An imager as in claim 5, wherein the first driver and sense circuit operates the first storage gates of the first set of pixels which are in a row of a pixel array and the second driver and sense circuit operates the second storage gates of the second set of pixels which are in a column of the pixel array.

7. An imager as in claim 6, further comprising digitizing and storing the signals from the first and second driver and sense circuits.

8. An imager as in claim 7, wherein the digitized signals are stored in a line buffer memory.

9. An imager as in claim 5, further comprising pixels arranged in a third pixel set, each pixel of the third set further comprising a third storage gate for storing charge originating at a respective photosensor, the imager further comprising a third driver and sense circuit associated with the third storage gates, the third driver and sense circuit configured to control operation of the third storage gates and provide a signal having a component representing charge stored by the third storage gates of the third pixel set.

10. An imager as in claim 9, wherein the third storage gates are in pixels of the third set which are arranged in a diagonal pattern within a pixel array.

11. An imager as in claim 9, wherein the third storage gates are in pixels of the third pixel set which are arranged in a non-linear pattern in a pixel array.

12. An imager as in claim 11, wherein the pattern is a serpentine pattern.

13. An imager as in claim 2, wherein the signal from the first driver and sense circuit is configured to provide a signature for a frame image.

14. An imager pixel as in claim 13, wherein the signal from the first driver and sense circuit is respectively provided in a plurality of framed images and the signals from the plurality of frame images are configured to provide a respective signature for the plurality of frame images.

15. An imager as in claim 14, wherein the signals from the first driver and sense circuit are used in a motion detection operation.

16. An imager as in claim 14, wherein the signals from the first driver and sense circuit are used in an auto exposure operation.

17. An imager as in claim 14, wherein the signals from the first driver and sense circuit are used in an auto-white balancing operation.

18. An imager pixel as in claim 14, wherein the respective signatures are used to determine object movement from one frame image to another frame image.

19. An imager as in claim 2, wherein the signal from the first driver and sense circuit includes a component representing parasitic capacitance.

20. An imager as in claim 1, further comprising a sample and hold circuit having a sampling capacitor switchably coupled to the output transistor and configured to store a charge corresponding to the first signal.

21. An imager as in claim 1, wherein the first driver and sense circuit includes an amplifier switchably coupled to a gate control line connected to the charge storage gate, wherein the storage capacitor is switchably coupled to the amplifier and the gate control line.

22. An imager as in claim 21, wherein the first driver and sense circuit provides the second signal onto the gate control line, and wherein the sensed charge corresponds to an amount of charge driven out to the gate control line.