Apparatus and method for improved precision of phase difference detection

Patent metadata

Field	Value
Publication number	US-10510786-B2
Application number	US-201815926528-A
Country	US
Kind code	B2
Filing date	Mar 20, 2018
Priority date	Jul 5, 2013
Publication date	Dec 17, 2019
Grant date	Dec 17, 2019

Abstract

The present technology relates to a solid-state imaging device and a driving method thereof, and an electronic apparatus that make it possible to improve the precision of phase difference detection while suppressing deterioration of resolution in a solid-state imaging device having a global shutter function and a phase difference AF function. Provided is a solid-state imaging device including: a pixel array unit including, as pixels including an on-chip lens, a photoelectric conversion unit, and a charge accumulation unit, imaging pixels for generating a captured image and phase difference detection pixels for performing phase difference detection arrayed therein; and a driving control unit configured to control driving of the pixels. The imaging pixel is formed with the charge accumulation unit shielded from light. The phase difference detection pixel is formed in a manner that at least part of at least one of the photoelectric conversion unit and the charge accumulation unit refrains from being shielded from light. The present technology can be applied to, for example, a CMOS image sensor.

First claim

The invention claimed is:

1. A solid-state imaging device, comprising:
a pixel array unit comprising a plurality of imaging pixels for generation of a captured image and a plurality of phase difference detection pixels for phase difference detection,
wherein each of a first imaging pixel of the plurality of imaging pixels and a first phase difference detection pixel of the plurality of phase difference detection pixels comprise an on-chip lens, a first photoelectric conversion unit, and a charge accumulation unit; and
a driving control unit configured to drive the plurality of imaging pixels and the plurality of phase difference detection pixels,
wherein the charge accumulation unit of the first imaging pixel is shielded from light,
wherein at least one of a part of the first photoelectric conversion unit or a part of the charge accumulation unit of the first phase difference detection pixel is unshielded from the light,
wherein the first phase difference detection pixel shares a constituent element with another pixel of the pixel array unit,
wherein the constituent element includes at least one of a floating diffusion region, a reset transistor, an amplifier transistor, or a selection transistor,
wherein the charge accumulation unit is configured to retain charge from the first photoelectric conversion unit,
wherein the first phase difference detection pixel includes a transfer electrode,
wherein the transfer electrode is configured to transfer charge from the first photoelectric conversion unit to the charge accumulation unit,
wherein the transfer electrode is above the charge accumulation unit, and
wherein the transfer electrode comprise a transparent conductive film.

2. The solid-state imaging device according to claim 1 ,
wherein the driving control unit is further configured to: read, during phase difference detection, charge accumulated in at least one of the part of the first photoelectric conversion unit or the part of the charge accumulation unit, and
concurrently accumulate charge in the plurality of imaging pixels for the generation of the captured image.

3. The solid-state imaging device according to claim 2 ,
wherein the first phase difference detection pixel includes a light-shielding film, and
wherein the light shielding film comprises one of a first opening or a second opening.

4. The solid-state imaging device according to claim 3 ,
wherein the charge accumulation unit is configured to retain charge from the first photoelectric conversion unit.

5. The solid-state imaging device according to claim 4 ,
wherein the first photoelectric conversion unit is adjacent to the charge accumulation unit in a first direction in which a pair of phase difference detection pixels of the plurality of phase difference detection pixels are arrayed.

6. The solid-state imaging device according to claim 5 ,
wherein during phase difference detection, the driving control unit is further configured to read charge accumulated in the first photoelectric conversion unit in one of the pair of phase difference detection pixels, and read charge accumulated in the charge accumulation unit in the other of the pair of phase difference detection pixels.

7. The solid-state imaging device according to claim 4 ,
wherein the first photoelectric conversion unit is adjacent to the charge accumulation unit in a first direction in which a pair of phase difference detection pixels, of the plurality of phase difference detection pixels, are arrayed, and
wherein a first half of the first photoelectric conversion unit in the first direction includes the first opening in one of the pair of phase difference detection pixels, and a second half of the first photoelectric conversion unit in the first direction includes the first opening in the other of the pair of phase difference detection pixels.

8. The solid-state imaging device according to claim 4 ,
wherein a pair of phase difference detection pixels of the plurality of phase difference detection pixels includes a plurality of first photoelectric conversion units and a plurality of charge accumulation units in positions with mirror symmetry with respect to a boundary of the pair of phase difference detection pixels, and
wherein, in each of the pair of phase difference detection pixels, the first photoelectric conversion unit includes the first opening.

9. The solid-state imaging device according to claim 4 ,
wherein the first photoelectric conversion unit is adjacent to the charge accumulation unit in a second direction perpendicular to a first direction,
wherein the first direction is a direction in which a pair of phase difference detection pixels, of the plurality of phase difference detection pixels, are arrayed, and
wherein a first half of the photoelectric conversion unit and the charge accumulation unit in the first direction includes a third opening of a plurality of openings in one of a pair of phase difference detection pixels, and a second half of the first photoelectric conversion unit and the charge accumulation unit in the first direction includes a fourth opening in the other of the pair of phase difference detection pixels.

10. The solid-state imaging device according to claim 9 ,
wherein during phase difference detection, the driving control unit is further configured to concurrently read charge accumulated in the first photoelectric conversion unit and the charge accumulation unit in the one of the pair of phase difference detection pixels, and concurrently read charge accumulated in the first photoelectric conversion unit and the charge accumulation unit in the other of the pair of phase difference detection pixels.

11. The solid-state imaging device according to claim 3 ,
wherein, in the first phase difference detection pixel, the charge accumulation unit is a second photoelectric conversion unit that is adjacent to the first photoelectric conversion unit in a first direction, wherein the first direction is a direction in which a pair of phase difference detection pixels, of the plurality of phase difference detection pixels, are arrayed, and
wherein the first photoelectric conversion unit includes the first opening of the plurality of openings in one of the pair of phase difference detection pixels, and the second photoelectric conversion unit includes the second opening of the plurality of openings in the other of the pair of phase difference detection pixels.

12. The solid-state imaging device according to claim 2 ,
wherein the first phase difference detection pixel includes the first photoelectric conversion unit and the charge accumulation unit in symmetrical positions in a direction, with respect to an optical axis of the on-chip lens, and
wherein during phase difference detection, the driving control unit is further configured to read charge accumulated in the first photoelectric conversion unit in the first phase difference detection pixel and charge accumulated in the charge accumulation unit in the first phase difference detection pixel separately.

13. The solid-state imaging device according to claim 12 ,
wherein the charge accumulation unit is configured to retain charge from the first photoelectric conversion unit.

14. The solid-state imaging device according to claim 12 ,
wherein the first phase difference detection pixel includes a light-shielding film,
wherein the light-shielding film includes a plurality of openings at the part of the first photoelectric conversion unit and the part of the charge accumulation unit, and
wherein the plurality of openings are in the symmetrical positions in the direction, with respect to the optical

Assignees

• Sony Corp

Inventors

• Okuno Jun
• Yamashita Kazuyoshi

Classifications

• H04N23/672

  based on the phase difference signals · CPC title

• H04N25/134

  based on three different wavelength filter elements · CPC title

• H04N25/704

  Pixels specially adapted for focusing, e.g. phase difference pixel sets · CPC title

• H01L27/14609

  Electricity · mapped topic

• H01L27/14645

  Electricity · mapped topic