Image sensor and image capturing device

Abstract

An image sensor includes: image capturing pixels and focus detection pixels disposed together on a single substrate; and adjacent pixels that are not equipped with a photoelectric conversion unit and are disposed adjacent to the focus detection pixels.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the layout (a front view) of the image capturing pixels and the focus detection pixels adopted in the image sensor achieved in an embodiment;

FIGS. 2A, 2B and 2C are front views of an image capturing pixel, a dummy pixel and a focus detection pixel respectively;

FIG. 3 is a sectional view of an image capturing pixel;

FIG. 4 is a sectional view of a focus detection pixel;

FIG. 5 illustrates the principal of the focus detection achieved by using the image sensor in the embodiment;

FIG. 6 presents an example in which the read circuits of the image sensor adopting the pixel layout in FIG. 1 are constituted with MOS switches;

FIG. 7 presents an example in which the read circuits of the image sensor adopting the pixel layout in FIG. 1 is constituted with CCDs (charge transfer device);

FIGS. 8A and 8B each show a light blocking member disposed at a focus detection pixel;

FIG. 9 shows the structure of an image capturing device equipped with the image sensor in the embodiment;

FIG. 10 presents a flowchart of the operation executed in the digital still camera (image capturing device) in FIG. 9;

FIG. 11 presents an example of a variation of the layout for the image capturing pixels and the focus detection pixels;

FIG. 12 presents another example of a variation of the layout of the image capturing pixels and the focus detection pixels;

FIG. 13 presents yet another example of a variation of the layout of the image capturing pixels and the focus detection pixels;

FIG. 14 presents yet another example of a variation of the layout of the image capturing pixels and the focus detection pixels;

FIG. 15 presents yet another example of a variation of the layout of the image capturing pixels and the focus detection pixels; and

FIG. 16 presents yet another example of a variation of the layout of the image capturing pixels and the focus detection pixels.

Claims

1. An image sensor, comprising: image capturing pixels and focus detection pixels disposed together on a single substrate; andadjacent pixels that are not equipped with a photoelectric conversion unit and are disposed adjacent to the focus detection pixels.

2. An image sensor according to claim 1, further comprising: read circuits that read out photoelectric conversion outputs of the focus detection pixels that are disposed at the adjacent pixels.

3. An image sensor according to claim 1, wherein: the image capturing pixels and the focus detection pixels assume sizes equal to each other.

4. An image sensor according to claim 1, wherein: each of the image capturing pixels includes a single photoelectric conversion unit;each of the focus detection pixels includes a pair of photoelectric conversion units; anda micro-lens through which incident light is condensed onto the photoelectric conversion unit(s) is disposed at each of the image capturing pixels and the focus detection pixels

5. An image sensor according to claim 1, wherein: the image capturing pixels are arrayed two-dimensionally; andthe focus detection pixels are arrayed in a line.

6. An image sensor according to claim 5, wherein: the focus detection pixels and the adjacent pixels are arrayed in a line.

7. An image sensor according to claim 6, further comprising: an optical low pass filter disposed so as to project image light fluxes in double along a direction in which the focus detection pixels and the adjacent pixels are arrayed.

8. An image sensor according to claim 1, further comprising: color filters that are disposed at the pixels so as to achieve a specific color array, wherein:the focus detection pixels are disposed at positions corresponding to color filters set with a highest density in the specific color array.

9. An image sensor according to claim 1, wherein: the focus detection pixels each include a regulating member for regulating an area over which light is received at a photoelectric conversion unit thereof and an opening at the regulating member assumes a same shape as a shape of a light receiving area at a photoelectric conversion unit in each of the image capturing pixels.

10. An image sensor according to claim 1, wherein: the focus detection pixels each include a regulating member for regulating an area over which light is received at a photoelectric conversion unit thereof and an opening at the regulating member assumes a circular shape with an area smaller than a light receiving area at a photoelectric conversion unit in each of the image capturing pixels.

11. An image capturing device, comprising: an image sensor according to claim 1;an optical system that forms an image on the image sensor;an image capturing unit that generates an image based upon outputs from the image capturing pixels in the image sensor; anda focus detection unit that detects a state of focus adjustment achieved with the optical system based upon outputs from the focus detection pixels in the image sensor.

12. An image capturing device according to claim 11, wherein: color filters corresponding to a specific color are disposed at the focus detection pixels in the image sensor; andthe image capturing unit combines outputs from a plurality of photoelectric conversion units at each focus detection pixel and uses the combined output as a substitute for an output from an image capturing pixel.

13. An image capturing device, comprising: an image sensor that includes two-dimensionally arrayed image capturing pixels each equipped with a color filter and a photoelectric conversion unit, and focus detection pixels, each equipped with a color filter corresponding to a specific color and a pair of photoelectric conversion units that are disposed in part of an array of the image capturing pixels;an optical system that forms an image on the image sensor;a combining unit that combines outputs of the pair of photoelectric conversion units at each focus detection pixel;a correction unit that corrects an output from the combining unit so that an output level of the output from the combining unit is equalized to an output level of a hypothetical image capturing pixel with a color filter corresponding to the specific color hypothetically occupying a position actually assumed by the focus detection pixel;an image capturing unit that generates an image based upon outputs from the image capturing pixels and outputs from the focus detection pixels having been corrected by the correction unit; anda focus detection unit that detects a state of focus adjustment achieved with the optical system based upon outputs from the focus detection pixels.

14. A camera, comprising: an image sensor according to claim 1.

15. An image capturing method comprising: disposing image capturing pixels and focus detection pixels together on a single substrate;disposing adjacent pixels equipped with no photoelectric conversion unit at positions adjacent to the focus detection pixels; andphotoelectrically converting a light flux entering each of the image capturing pixels and the focus detection pixels.

16. An image capturing method according to claim 15, wherein: read circuits that read out photoelectric conversion outputs from the focus detection pixels are disposed at the adjacent pixels; andthe photoelectric conversion outputs from the focus detection pixels are read out via the read circuits.

17. An image capturing method according to claim 15, wherein: a plurality of photoelectric conversion units are disposed at each of the focus detection pixels.

18. An image capturing method according to claim 17, wherein: the plurality of photoelectric conversion units execute photoelectric conversion independently of one another to photoelectrically convert light fluxes entering therein via a single micro-lens disposed in close proximity to the focus detection pixel.

19. An image capturing method according to claim 16, wherein: a plurality of photoelectric conversion units are disposed at each of the focus detection pixels; andphotoelectric conversion outputs from some of the plurality of photoelectric conversion units are output via the read circuits.

20. An image capturing method according to claim 15, wherein: a light flux entering each of the focus detection pixels is also made to enter an adjacent pixel set next to the focus detection pixel via an optical member.

21. An image capturing method according to claim 15, wherein: a light flux enters each of the image capturing pixels via a color filter constituting part of a specific color array; anda light flux enters each of the focus detection pixels via a color filter corresponding to a color disposed with a highest density in the specific color array achieved with color filters.

22. An image capturing method, comprising: disposing image capturing pixels and focus detection pixels together on a single substrate;disposing adjacent pixels equipped with no photoelectric conversion unit at positions adjacent to the focus detection pixels;photoelectrically converting via an optical system individual light fluxes entering the image capturing pixels and the focus detection pixels;generating an image based upon photoelectric conversion outputs from the image capturing pixels; anddetecting a state of focus adjustment achieved via the optical system based upon photoelectric conversion outputs from the focus detection pixels.

23. An image capturing method according to claim 22, wherein: light fluxes enter the focus detection pixels via color filters corresponding to a specific color; andthe image is generated based upon the outputs from the image capturing pixels and the outputs from the focus detection pixels.

24. An image sensor, comprising; first pixels that capture an image;second pixels that detect focus condition of an optical system, the first pixels and the second pixels being disposed together on a single substrate; andthird pixels that are disposed adjacent to the second pixels without a photoelectric conversion unit.

25. An image sensor according to claim 24, wherein: each of the first pixels comprises a first photoelectric conversion unit that converts a light from the optical system into an electric signal respectively; andeach of the second pixels comprises a second photoelectric conversion unit that is different from the first photoelectric conversion unit to convert the light from the optical system.

26. An image capturing device, comprising: an image sensor that includes two-dimensionally arrayed image capturing pixels each equipped with a color filter and a photoelectric conversion unit, and focus detection pixels, each equipped with a color filter corresponding to a specific color and a pair of photoelectric conversion units that are disposed in part of an array of the image capturing pixels;a combining unit that combines outputs of the pair of photoelectric conversion units at each focus detection pixel;a correction unit that corrects an output from the combining unit so that an output level of the output from the combining unit is equalized to an output level of a hypothetical image capturing pixel with a color filter corresponding to the specific color hypothetically occupying a position actually assumed by the focus detection pixel;an image capturing unit that generates an image based upon outputs from the image capturing pixels and outputs from the focus detection pixels having been corrected by the correction unit; anda focus detection unit that detects a state of focus adjustment achieved with an optical system based upon outputs from the focus detection pixels.