Image sensor and image-capturing device

• US 20090135273A1
• Filed: 11/24/2008
• Published: 05/28/2009
• Est. Priority Date: 11/28/2007
• Status: Active Grant

• Current Assignee: Nikon Corporation
• Original Assignee: Nikon Corporation
• Inventors: Kusaka, Yosuke
• Granted Patent: US 8,111,310 B2
• Time in Patent Office: Days
• US Class Current: 348/222.100
• CPC Class Codes: H04N 23/63 by using electronic viewfinders
• CPC Class Codes: H04N 23/672 based on the phase difference signals
• CPC Class Codes: H04N 23/843 Demosaicing, e.g. interpolating colour pixel values
• CPC Class Codes: H04N 25/134 based on three different wavelength filter elements
• CPC Class Codes: H04N 25/44 by partially reading an SSIS array
• CPC Class Codes: H04N 25/704 Pixels specially adapted for focusing, e.g. phase difference pixel sets

Abstract

An image sensor includes: a plurality of first pixels that receive a light flux having passed through an optical system and output pixel signals to be used as image signals; a plurality of second pixels that receive a light flux having passed through the optical system and output pixel signals to be used as signals other than the image signals; a plurality of first pixel rows, each of which includes an array made up with a plurality of first pixels; at least one second pixel row that includes an array made up with first pixels and second pixels; an output circuit that outputs a read signal in response to which pixel signals output at the first pixels are read out from the first pixel rows over first pixel intervals and pixel signals output at the second pixels are read out from the second pixel row over second pixel intervals, different from the first pixel intervals, the output circuit outputting externally the pixel signals having been read out; and a switching device that selects a specific pixel row, either one of the first pixel rows or the second pixel row, from which pixel signals are to be read out by the output circuit.

Claims

1. An image sensor, comprising:

a plurality of first pixels that receive a light flux having passed through an optical system and output pixel signals to be used as image signals;

a plurality of second pixels that receive a light flux having passed through the optical system and output pixel signals to be used as signals other than the image signals;

a plurality of first pixel rows, each of which includes an array made up with a plurality of first pixels;

at least one second pixel row that includes an array made up with first pixels and second pixels;

an output circuit that outputs a read signal in response to which pixel signals output at the first pixels are read out from the first pixel rows over first pixel intervals and pixel signals output at the second pixels are read out from the second pixel row over second pixel intervals, different from the first pixel intervals, the output circuit outputting externally the pixel signals having been read out; and

a switching device that selects a specific pixel row, either one of the first pixel rows or the second pixel row, from which pixel signals are to be readout by the output circuit.

2. An image sensor according to claim 1, further comprising:

a selector that selects a circuit via which the read signal is manipulated in correspondence to the specific pixel row from which the output circuit is to read out pixel signals; and

line memories that read out and hold pixel signals from each of the first pixel rows and the second pixel row.

3. An image sensor according to claim 1, wherein:

the first pixels each receive a light flux having passed through the optical system substantially over an entire range of a pupil thereof; and

the second pixels each receive a light flux having passed through the optical system over a partial area in the pupil thereof.

4. An image sensor according to claim 3, wherein:

the second pixels are focus detection pixels each equipped with a micro lens and a first photoelectric conversion unit that receives the light flux via the micro lens; and

first focus detection pixels and second focus detection pixels that receive light fluxes having passed through different partial areas of the pupil are disposed alternately to each other.

5. An image sensor according to claim 2, further comprising:

a first output circuit and a second output circuit constituting the output circuit, which respectively output a first read signal and a second read signal to the line memories, wherein;

the selector selects either the first output circuit or the second output circuit depending upon the specific pixel row from which pixel signals are to be read out by the output circuit.

6. An image sensor according to claim 2, further comprising:

a signal line through which the read signal is output from the output circuit to the line memories, wherein;

the selector selects the signal line in order to manipulate the read signal into a first read signal or a second read signal assuming cycles different from cycles of the first read signal, depending upon the specific pixel row from which pixel signals are to be read out by the output circuit.

7. An image sensor according to claim 2, wherein:

the selector adjusts cycles of the read signal when the output circuit is to read out pixel signals from the second pixel row.

8. An image sensor according to claim 2, wherein:

if a first read signal is input to the line memories, pixel signals at the first pixels are read out sequentially over predetermined intervals set as the first pixel intervals, whereas if a second read signal is input to the line memories, pixel signals at the second pixels set in succession are sequentially read out consecutively with no intervals set as the second pixel intervals, and the output circuit outputs the pixel signals thus read out externally.

9. An image-capturing device, comprising:

an image sensor according to claim 1;

a read circuit that cyclically reads out the pixel signals output from the output circuit;

a display controller that displays an image based upon pixel signals having been first read out from the first pixel rows by the output circuit in response to the read signal and then read out by the read circuit; and

a focus detector that detects a focusing condition of the optical system based upon pixel signals having been first read out from the second pixel row by the output circuit in response to the read signal and then read out by the read circuit.

10. An image-capturing device according to claim 9, wherein:

the display controller generates image signals at positions occupied by the second pixels through interpolation executed based upon pixel signals output from the first pixels present near the second pixels.

11. An image-capturing device according to claim 9, further comprising:

a focus adjuster that executes focus adjustment for the optical system based upon the focusing condition.

12. An image sensor, comprising:

a plurality of first pixels that receive a light flux having passed through an optical system and output pixel signals to be used as image signals;

a plurality of second pixels that receive a light flux having passed through the optical system and output pixel signals to be used as signals other than image signals;

a plurality of first pixel rows, each of which includes an array made up with a plurality of first pixels;

at least one second pixel row that includes an array made up with first pixels and second pixels and is set among the plurality of first pixel rows;

an output circuit that assumes a first read mode or a second read mode, wherein;

the output circuit outputs pixel signals at the first pixels, obtained in specific first pixel rows present over predetermined row intervals among the plurality of pixel rows in the first read mode; and

the output circuit outputs pixel signals at the first pixels and the second pixels, obtained by replacing at least one of the specific first pixel rows with the second pixel row, in the second read mode.

13. An image-capturing device, comprising:

an image sensor according to claim 12;

a read circuit that cyclically reads out the pixel signals output from the output circuit;

a display controller that displays an image based upon pixel signals at the first pixels read out by the read circuit; and

a focus detector that detects a focusing condition of the optical system based upon pixel signals at the second pixels read out by the read circuit, wherein;

the output circuit is invariably engaged in operation in the second read mode in response to an image display instruction.

14. An image-capturing device according to claim 13, wherein:

the display controller generates image signals at positions occupied by the second pixels through interpolation executed based upon pixel signals output from the first pixels present near the second pixels.