IMAGE PICKUP DEVICE, ITS CONTROL METHOD, AND CAMERA

• US 20110074993A1
• Filed: 12/06/2010
• Published: 03/31/2011
• Est. Priority Date: 01/14/2005
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: SAKURAI, KATSUHITO, OKITA, AKIRA, KOIZUMI, TORU, UENO, ISAMU
• Granted Patent: US 8,883,526 B2
• Time in Patent Office: Days
• US Class Current: 348/300
• CPC Class Codes: H01L 27/14603 Special geometry or disposition of pixel-elements, address-lines or gate-electrodes
• CPC Class Codes: H04N 23/70 Circuitry for compensating brightness variation in the scene
• CPC Class Codes: H04N 23/741 by increasing the dynamic range of the image compared to the dynamic range of the electronic image sensors
• CPC Class Codes: H04N 25/575 with a response composed of multiple slopes
• CPC Class Codes: H04N 25/583 with different integration times
• CPC Class Codes: H04N 25/587 acquired sequentially, e.g. using the combination of odd and even image fields
• CPC Class Codes: H04N 25/59 by controlling the amount of charge storable in the pixel, e.g. modification of the charge conversion ratio of the floating node capacitance
• CPC Class Codes: H04N 25/621 for the control of blooming
• CPC Class Codes: H04N 25/75 Circuitry for providing, modifying or processing image signals from the pixel array
• CPC Class Codes: H04N 3/155 Control of the image-sensor operation, e.g. image processing within the image-sensor

Abstract

An image pickup device, wherein a part of the carriers overflowing from the photoelectric conversion unit for a period of photoelectrically generating and accumulating the carriers may be flowed into the floating diffusion region, and a pixel signal generating unit generating a pixel signal according to the carriers stored in the photoelectric conversion unit and the carriers having overflowed into the floating diffusion region, is provided. The expansion of a dynamic range and the improvement of an image quality can be provided by controlling a ratio of the carriers flowing into the floating diffusion region to the carriers overflowing from such a photoelectric conversion unit at high accuracy.

Claims

1-10. -10. (canceled)

11. A method of driving an image pickup device that includes a photoelectric conversion unit for generating carriers by photoelectric conversion and accumulating the carriers;

a transfer transistor for transferring a signal from the photoelectric conversion unit, a floating diffusion region to which carriers of the photoelectric conversion unit are transferred by the transfer transistor, and a pixel signal generating unit for processing the signal from the photoelectric conversion unit, the method comprising steps of;

controlling a transfer gate by controlling a gate voltage of the transfer transistor so that a part of the carriers, which overflow from the photoelectric conversion unit, flows into the floating diffusion region for a period in which the photoelectric conversion unit is generating and accumulating carriers; and

generating a pixel signal based on accumulated carriers in the photoelectric conversion unit and overflowed carriers in the floating diffusion region.

12. The method according to claim 11, wherein, in the step of controlling, the gate voltage of the transfer gate is controlled according to an amplification degree of the pixel signal.

13. The method according to claim 11, wherein, in the step of controlling, the gate voltage of the transfer gate is controlled according to a temperature during the period in which the photoelectric conversion unit is generating and accumulating carriers.

14. The method according to claim 11, wherein, in the step of controlling, the gate voltage of the transfer gate is controlled so that a height of a potential barrier under the transfer gate between the photoelectric conversion unit and the floating diffusion region is a lowest height among heights of potential barriers surrounding the photoelectric conversion unit.

15. The method according to claim 11,

wherein the image pickup device further includes a first element adjacent to the photoelectric conversion unit and connected a power source, and

wherein the gate voltage of the transfer gate is controlled so that a height of a potential barrier under the transfer gate is same as a height of a potential barrier between the photoelectric conversion unit and the first element.

16. A method of controlling a solid image pickup device that includes a photoelectric conversion unit for generating carriers by photoelectric conversion and accumulating the carriers, a transfer transistor for transferring the carrier from the photoelectric conversion unit, a floating diffusion region to which carriers of the photoelectric conversion unit are transferred by the transfer transistor, a first element adjacent to the photoelectric conversion unit and set to a fixed potential, and a transfer transistor control unit for controlling a potential of the transfer transistor, the method comprising controlling a gate voltage of the transfer transistor by the transfer transistor control unit during a period in which the photoelectric conversion unit is generating and accumulating carriers in order to control a ratio of carriers flowing to the floating diffusion region to carriers flowing to the first element.

17. The method according to claim 16, wherein, during the period in which the photoelectric conversion unit is generating and accumulating carriers, the transfer transistor control unit controls the gate voltage of the transfer transistor to a third gate voltage, and the third gate voltage is between a first voltage for turning on the transfer transistor and a second voltage for turning off the transfer transistor.

18. The method according to claim 16, further comprising generating, by a pixel signal generating unit, a pixel signal according to carriers based on accumulated carriers in the photoelectric conversion unit and overflowed carriers in the floating diffusion region.