JP7180664B2 - Imaging element and imaging device - Google Patents

Description

The present invention relates to an imaging device and an imaging device .

2. Description of the Related Art Conventionally, there has been known an imaging device provided with focus detection pixels for performing pupil-dividing focus detection on an imaging surface. Conventionally, there has been a problem that focus detection is difficult when the focus is largely out of focus (during large defocus).

JP 2005-106994 A

According to the first aspect, the imaging device includes a first light shielding section that shields part of light that has passed through the optical system and the first microlens, and a first photoelectric conversion section that photoelectrically converts the light to generate electric charges. , a first pixel that outputs a first signal based on the charge generated by the first photoelectric conversion unit; a second light shielding portion having a different area, a second photoelectric conversion portion photoelectrically converting light to generate an electric charge, a second pixel outputting a second signal based on the electric charge generated by the second photoelectric conversion portion; a third photoelectric conversion unit and a fourth photoelectric conversion unit photoelectrically converting light transmitted through the optical system and the third microlens to generate electric charges; and a third signal based on the electric charges generated by the third photoelectric conversion unit. and a third pixel that outputs a fourth signal based on the charge generated by the fourth photoelectric conversion unit, wherein the number of the first pixels and the number of the second pixels are equal to the number of the third pixels less than
According to a second aspect, an imaging device includes the imaging device described above, and a generator that generates image data based on a signal output from the imaging device.

1 is a cross-sectional view schematically showing the configuration of a camera system according to a first embodiment of the invention; FIG. 2 is a plan view schematically showing an imaging surface 20 of an imaging device 210. FIG. 3 is an explanatory diagram of an imaging and focus detection pixel 301; FIG. FIG. 4 is an explanatory diagram of first focus detection pixels 302NR and NL; FIG. 4 is an explanatory diagram of second focus detection pixels 302SR and SL; FIG. 11 is an explanatory diagram of third focus detection pixels 302LR and LL; 2 is a plan view schematically showing an imaging surface 20 of an imaging device 210. FIG. It is the figure which expanded a part in the 1st area|region 60a. It is the figure which expanded a part in the 2nd area|region 60b. It is the figure which expanded a part in the 3rd area|region 60c. 4 is a flowchart of control processing executed by a body CPU 220; 12 is a flowchart of AF processing called from step S30 in FIG. 11; 12 is a flowchart of AF processing called from step S30 in FIG. 11; 2 is a perspective view schematically showing the structure of an imaging element 210a; FIG. 3 is a cross-sectional view schematically showing an imaging/focus detection pixel 301 and a focus detection pixel 302. FIG. FIG. 3 is a plan view enlarging a part of the first region 60a of the imaging device 210a; FIG. 11 is a plan view enlarging a part of the second region 60b of the imaging element 210a; FIG. 11 is a plan view enlarging a portion of the inside of a third region 60c of the imaging device 210a; FIG. 3 is a cross-sectional view schematically showing a light flux from a light point P on an image plane S to be synthesized and an imaging device 210a. It is explanatory drawing of the 1st focus detection pixel which concerns on a modification. It is explanatory drawing of the imaging surface which concerns on a modification. FIG. 11 is an explanatory diagram of imaging and focus detection pixels according to a modification;

(First embodiment)
FIG. 1 is a cross-sectional view schematically showing the configuration of a camera system according to the first embodiment of the invention. Note that FIG. 1 mainly shows each part particularly related to the present invention, and the other parts constituting the camera system 1 are omitted from the illustration. In the following, each part particularly related to the present invention will be mainly described, and description of other parts will be omitted.

The camera system 1 is a so-called single-lens reflex digital camera. A camera system 1 is composed of an interchangeable lens 100 and a camera body 200 . The user can select any one of a plurality of types of interchangeable lenses 100 that are compatible with the camera body 200 (that can be attached to the camera body 200), attach it to the camera body 200, and perform photography. FIG. 1 illustrates one of a plurality of types of interchangeable lenses 100 .

The camera body 200 and the interchangeable lens 100 have, for example, a bayonet-type lens mount mechanism. The mounting of the interchangeable lens 100 to the camera body 200 is performed by fitting the mount portion of the interchangeable lens 100 into the mount portion of the camera body 200 .

Interchangeable lens 100 includes imaging optical system 110 , lens CPU 120 , and diaphragm 130 . An imaging optical system 110 is composed of a lens 111 and a focusing lens 112 . The imaging optical system 110 forms a subject image on an imaging surface of an imaging device 210, which will be described later. The exit pupil position of the imaging optical system 110 differs depending on the type of the interchangeable lens 100 .

The camera body 200 includes an imaging element 210 , a body CPU 220 , a focus adjustment section 230 , a ROM 240 and a display device 250 . The imaging device 210 is, for example, an imaging device such as a CCD or CMOS. The imaging device 210 receives subject light that has passed through the imaging optical system 110 and outputs an imaging signal and a focus detection signal. Body CPU 220 is composed of a microprocessor and its peripheral circuits (not shown). The body CPU 220 reads and executes a control program pre-stored in the ROM 240 which is a non-volatile storage medium, thereby controlling each section of the camera body 200 and performing data communication with the interchangeable lens 100 . The focus adjustment unit 230 includes an actuator (not shown) and drives the focusing lens 112 along the optical axis under the control of the body CPU 220 to adjust the focus of the imaging optical system 110 . The display device 250 is a display device such as a liquid crystal display, for example, and displays live view images, various setting screens, and the like.

The body CPU 220 has a first focus detection section 221 and a second focus detection section 222 in the form of software. These units are implemented in software by body CPU 220 executing a predetermined control program stored in ROM 240 .

The first focus detection unit 221 detects the focus adjustment state of the imaging optical system 110 based on focus detection signals output from imaging and focus detection pixels, which will be described later. The second focus detection section 222 detects the focus adjustment state of the imaging optical system 110 based on focus detection signals output from focus detection pixels, which will be described later.

(Description of image sensor 210)
FIG. 2A is a plan view schematically showing the imaging surface 20 of the imaging element 210. FIG. In FIG. 2A, for convenience of explanation, the direction parallel to the upper and lower sides of the imaging surface 20 (horizontal direction on the paper surface) is the X axis, and the direction parallel to the left and right sides of the imaging surface 20 (vertical direction on the paper surface) is A coordinate system is set with the Y-axis and the front-rear direction of the imaging surface 20, that is, the optical axis direction of the imaging optical system 110 as the Z-axis. The same coordinate system will be set for the subsequent drawings as well.

FIG. 2A shows a vertical line OX that is superimposed on the imaging surface 20 and bisects the imaging surface 20 in the horizontal direction (X-axis direction), and a vertical line OX that bisects the imaging surface 20 in the vertical direction (Y-axis direction). A horizontal line of equal division OY is shown. The intersection of vertical line OX and horizontal line OY substantially coincides with the optical axis of imaging optical system 110 . FIG. 2(b) is an enlarged schematic diagram of a region 20a near the center of the imaging surface 20 (near the intersection of the vertical line OX and the horizontal line OY) of the entire imaging surface 20 shown in FIG. 2(a). .

As shown in FIG. 2B, a large number of pixels 30 are arranged in a two-dimensional square on the imaging surface 20 . The pixels 30 include two types of pixels: imaging and focus detection pixels 301 used for both imaging and focus detection, and focus detection pixels 302 used only for focus detection. ), the two are illustrated without distinguishing between them. In the following, the imaging and focus detection pixel 301 will be described with particular attention paid to the imaging and focus detection pixel 301a located at the center of the imaging surface 20 (the intersection of the vertical line OX and the horizontal line OY).

3A is an enlarged plan view of an imaging/focus detection pixel 301a positioned at the center of the imaging surface 20 (the intersection of the vertical line OX and the horizontal line OY) among the pixels 30 shown in FIG. 2B. , and FIG. 3B is a sectional view of the imaging and focus detection pixel 301a. The imaging and focus detection pixel 301a has a microlens 31, a color filter 32, and a pair of photoelectric conversion units 34L and 34R. The pair of photoelectric conversion units 34L and 34R has a substantially semicircular shape obtained by dividing a circle along the Y-axis direction. That is, the pair of photoelectric conversion units 34L and 34R are arranged along the X-axis direction (focus detection direction). The maximum width of the pair of photoelectric conversion units 34L and 34R in the X-axis direction is W1.

The microlens 31 collects incident light to the imaging and focus detection pixel 301a to a pair of photoelectric conversion units 34L and 34R. This incident light passes through the color filter 32 and enters the pair of photoelectric conversion units 34L and 34R. The color filter 32 is formed for each pixel so as to transmit red, blue, or green light and not transmit other light. The color filters 32 of the imaging and focus detection pixels 301a are configured to form a so-called Bayer array. A wiring layer 33 is provided between the color filter 32 and the pair of photoelectric conversion units 34L and 34R. The wiring layer 33 is arranged between the pixels so as not to block incident light to the pair of photoelectric conversion units 34L and 34R.

A dashed line 41 illustrated in FIG. 3B represents the optical axis of the microlens 31 (hereinafter referred to as the optical axis 41). A dashed line 42 illustrated in FIG. 3B represents the center of the dividing position between the photoelectric conversion units 34L and 34R (hereinafter referred to as a dividing line 42). The photoelectric conversion units 34L and 34R have shapes that are symmetrical with respect to the dividing line 42 and are arranged symmetrically with respect to the dividing line 42 .

The pair of photoelectric conversion units 34L and 34R are, for example, photodiodes, and output photoelectric conversion signals obtained by photoelectrically converting incident light. The imaging/focus detection pixel 301a separately outputs the photoelectric conversion signal output from the photoelectric conversion unit 34L and the photoelectric conversion signal output from the photoelectric conversion unit 34R. A signal obtained by adding the pair of photoelectric conversion signals is substantially the same signal as an imaging signal output from a single photoelectric conversion section that substantially matches the outer shape of the pair of photoelectric conversion sections 34L and 34R. That is, the imaging/focus detection pixel 301a can output an imaging signal.

On the other hand, the photoelectric conversion signal output from the photoelectric conversion unit 34L and the photoelectric conversion signal output from the photoelectric conversion unit 34R correspond to a pair of light beams that have passed through a pair of areas of the exit pupil of the imaging optical system 110. Therefore, a signal composed of photoelectric conversion signals output from the photoelectric conversion units 34R of a large number of imaging and focus detection pixels 301a arranged in a row along the X-axis direction (predetermined focus detection direction, also referred to as the first direction). and a signal composed of photoelectric conversion signals output by the photoelectric conversion units 34L of the large number of imaging and focus detection pixels 301a. can be calculated. In other words, the imaging/focus detection pixel 301a can also output a focus detection signal capable of performing a well-known phase-difference type focus detection calculation.

As described above, the pair of photoelectric conversion units 34L and 34R included in the imaging/focus detection pixel 301a outputs photoelectric conversion signals that are used both as imaging signals and as focus detection signals of the pupil division method. Note that the process of adding a pair of photoelectrically converted signals to obtain an imaging signal and the process of using a pair of photoelectrically converted signals as a focus detection signal may be performed by the imaging and focus detection pixel 301a, or may be performed by the imaging element 210. may be executed by a dedicated circuit provided in the image sensor 210, or by a dedicated circuit provided outside the imaging device 210, or by the body CPU 220.

Next, another imaging and focus detection pixel 301b (see FIG. 2B), which is separated from the imaging and focus detection pixel 301a by 4 pixels in the right direction (+X direction) of the paper surface, will be described. FIG. 3C is a cross-sectional view of the imaging/focus detection pixel 301b. Similarly to the imaging and focus detection pixel 301a, the imaging and focus detection pixel 301b also has a microlens 31, a color filter 32, and a pair of photoelectric conversion units 34L and 34R. However, as is clear from a comparison between FIGS. 3(b) and 3(c), the imaging/focus detection pixel 301a is located between the position of the optical axis 41 of the microlens 31 and the position of the pair of photoelectric conversion units 34L and 34R. While the division line 42 representing the center of the division position is substantially aligned in the X-axis direction, the imaging/focus detection pixel 301b has the optical axis 41 and the division line 42 separated by a distance 40 in the X-axis direction. there is

As described above, in the imaging and focus detection pixel 301b located away from the center of the imaging surface 20, the position of the optical axis 41 of the microlens 31 and the dividing line 42 of the pair of photoelectric conversion units 34L and 34R are separated. The distance 40 increases as the distance from the center of the imaging surface 20 increases. The light flux that has passed through the imaging optical system 110 is incident on the imaging and focus detection pixel 301b from the upper left direction of the paper surface of FIG. 3C toward the lower right direction of the paper surface. A lens 31 is arranged at a distance 40 corresponding to the angle of incident light. 3B and 3C, only the displacement in the X-axis direction has been described, but the position of the microlens 31 and the position of the pair of photoelectric conversion units 34L and 34R are different in the Y-axis direction as well. are arranged as follows.

Next, the focus detection pixel 302 will be described. The imaging element 210 includes first focus detection pixels 302NL and 302NR, second focus detection pixels 302SL and 302SR, third focus detection pixels 302LL and 302LR, fourth focus detection pixels 302SNL, and 302SNR, fifth focus detection pixels 302LNL, and 302LNR. Locations where these focus detection pixels are arranged will be described in detail later, and the structure of these focus detection pixels will be described first.

FIG. 4A is a cross-sectional view of the first focus detection pixel 302NR. The first focus detection pixel 302NR has a microlens 31, a photoelectric conversion unit 34, and a light shielding member 35. The difference between the above-described imaging and focus detection pixel 301b and the first focus detection pixel 302NR is that it does not have the color filter 32, and instead of the pair of photoelectric conversion units 34L and 34R, a single undivided photoelectric conversion pixel is used. It has a portion 34 and a light shielding member 35 .

The light shielding member 35 is a thin film (light shielding film) that shields incident light. An opening 36NR is provided at a predetermined position (referred to as a first position) of the light shielding member 35 . Only the luminous flux that has passed through the opening 36 NR is incident on the photoelectric conversion section 34 , and the other luminous flux is blocked by the light shielding member 35 and does not enter the photoelectric conversion section 34 . The width of the aperture 36NR in the X-axis direction (focus detection direction) is W2, which is smaller than the width W1 in the X-axis direction of the photoelectric conversion units 34L and 34R shown in FIG.

FIG. 4B is a cross-sectional view of the first focus detection pixel 302NL. The first focus detection pixel 302NL has substantially the same configuration as the first focus detection pixel 302NR. This is the difference between The opening 36NL has the same size and shape as the opening 36NR, but the position on the light blocking member 35 is different from that of the opening 36NR.

The openings 36NR and 36NL are located on the left and right sides of the one-dot chain line 44N. That is, the dashed-dotted line 44N is a straight line that defines the dividing center of the openings 36NR and 36NL. In the following description, the dashed-dotted line 44N is called a dividing line 44N. The first focus detection pixel 302NR outputs a light receiving signal corresponding to the light image of the subject formed on the right side of the dividing line 44N, and the first focus detection pixel 302NL outputs the light of the subject formed on the left side of the dividing line 44N. A received light signal corresponding to the image is output. In other words, the first focus detection pixels 302NR and 302NL respectively receive a pair of pupil-divided light beams and output a pair of focus detection signals.

The width of the openings 36NR and 36NL in the focus detection direction (X-axis direction) is smaller than the width of the photoelectric conversion units 34R and 34L described in FIGS. 3A to 3C in the focus detection direction (X-axis direction). . That is, the photoelectric conversion units 34 of the first focus detection pixels 302NR and 302NL receive a more limited light flux than the photoelectric conversion units 34R and 34L of the imaging and focus detection pixel 301 . Therefore, when the defocus amount is particularly large, that is, when the subject portion to be focused is largely out of focus, the focus detection signals output from the first focus detection pixels 302NR and 302NL are The contrast is stronger than the focus detection signal output from 301 . Therefore, even if it is difficult to detect the phase difference with the focus detection signal output from the imaging and focus detection pixel 301, the phase difference can be detected from the focus detection signal output from the first focus detection pixels 302NR and 302NL. It is possible to

In the following description, the width of the apertures 36NR and 36NL in the focus detection direction is smaller than the width of the photoelectric conversion units 34R and 34L in the focus detection direction (X-axis direction). The width in the focus detection direction (X-axis direction) is sometimes said to be smaller than the width in the focus detection direction (X-axis direction) of the photoelectric conversion units 34R and 34L. In other words, the "width of the photoelectric conversion section 34 in the focus detection direction (X-axis direction)" does not refer to the actual width of the photoelectric conversion section 34, but the width of the incident light range of the photoelectric conversion section 34. , "the width of the photoelectric conversion unit 34 in the focus detection direction (X-axis direction) is smaller than the width of the photoelectric conversion units 34R and 34L in the focus detection direction (X-axis direction)" means that the photoelectric conversion unit 34 is actually This includes the case where the width is formed to be small, and the case where the light blocking member 35 or the like is provided so that the incident range of the light incident on the photoelectric conversion portion 34 is small.

The dividing line 44N substantially coincides with the dividing line 42 that bisects the photoelectric conversion unit 34 in the horizontal direction (X-axis direction) of the drawing. 4A and 4B show a principal ray 43N passing through the vertex of the microlens 31 among the principal rays of the exit pupil of the imaging optical system 110. FIG. The principal ray 43N makes an angle θN with respect to the optical axis 41 of the microlens 31 . The position of the dividing line 44N corresponds to the position of the chief ray 43N assumed by the first focus detection pixels 302NR and 302NL.

5A is a cross-sectional view of the second focus detection pixel 302SR, and FIG. 5B is a cross-sectional view of the second focus detection pixel 302SL. The second focus detection pixels 302SR and 302SL have substantially the same configuration as the first focus detection pixels 302NR and 302NL shown in FIGS. The difference from the first focus detection pixels 302NR and 302NL is that apertures 36SR and 36SL are provided instead of 36NL.

The openings 36SR and 36SL have substantially the same size and shape as the openings 36NR and 36NL, respectively. The openings 36SR and 36SL are located on the left and right sides of the chain double-dashed line 44S. That is, the two-dot chain line 44S is a straight line that defines the division center of the openings 36SR and 36SL. In the following description, the chain double-dashed line 44S is called the division line 44S.

The dividing line 44S is located relatively to the right of the dividing line 44N shown in FIGS. 4(a) and 4(b). Accordingly, the dividing line 44S exists at a position a predetermined distance to the right from the dividing line 42 that bisects the photoelectric conversion section 34 in the horizontal direction (X-axis direction) of the paper surface.

5A and 5B show a principal ray 43S passing through the top of the microlens 31 among the principal rays of the exit pupil of the imaging optical system 110. FIG. The principal ray 43 S forms an angle θS with respect to the optical axis 41 of the microlens 31 . The angle θS is larger than the angle θN shown in FIGS. 4(a) and 4(b). That is, even if the exit pupil of the imaging optical system 110 is relatively close to the apertures 36NR and 36NL of the first focus detection pixels 302NR and 302NL, the subject light does not enter the apertures 36SR and 36SL. Subject light is incident on . The position of the dividing line 44S corresponds to the position of the chief ray 43S assumed by the second focus detection pixels 302SR and 302SL. Thus, the opening 36NR is arranged at the first position, while the opening 36SR is arranged at a second position different from the first position.

6A is a cross-sectional view of the third focus detection pixel 302LR, and FIG. 6B is a cross-sectional view of the third focus detection pixel 302LL. The third focus detection pixels 302LR and 302LL have substantially the same configuration as the first focus detection pixels 302NR and 302NL shown in FIGS. The difference from the first focus detection pixels 302NR and 302NL is that openings 36LR and 36LL are provided instead of 36NL.

The openings 36LR and 36LL have substantially the same size and shape as the openings 36NR and 36NL, respectively. The openings 36LR and 36LL are located on the left and right sides of the chain double-dashed line 44L. That is, the two-dot chain line 44L is a straight line that defines the division center of the openings 36LR and 36LL. In the following description, the chain double-dashed line 44L is called the dividing line 44L.

The dividing line 44L is positioned relatively to the left of the dividing line 44N shown in FIGS. 4(a) and 4(b). Therefore, the dividing line 44L is located at a predetermined distance to the left from the dividing line 42 that bisects the photoelectric conversion section 34 in the horizontal direction (X-axis direction) of the paper surface.

6A and 6B show a principal ray 43S passing through the vertex of the microlens 31 among the principal rays of the exit pupil of the imaging optical system 110. FIG. The principal ray 43L makes an angle θL with respect to the optical axis 41 of the microlens 31 . The angle θL is smaller than the angle θN shown in FIGS. 4(a) and 4(b). That is, even if the exit pupil of the imaging optical system 110 is at a relatively far position and subject light does not enter the apertures 36NR and 36NL of the first focus detection pixels 302NR and 302NL, the apertures 36LR and 36LL Subject light is incident on . The position of the dividing line 44L corresponds to the position of the principal ray 43L assumed by the third focus detection pixels 302LR and 302LL.

The focus detection pixels further include fourth focus detection pixels 302SNL and 302SNR (both not shown) and fifth focus detection pixels 302LNL and 302LNR (both not shown). The fourth focus detection pixels 302SNL and 302SNR correspond to the first focus detection pixels 302NL and 302NR, respectively, and the division center of the aperture provided in the light shielding member 35 is the division line 44N of the first focus detection pixels 302NL and 302NR. , and the dividing line 44L in the third focus detection pixels 302LL and 302LR. That is, the exit pupil of the imaging optical system 110 is positioned farther than the positions assumed by the first focus detection pixels 302NL and 302NR and closer than the positions assumed by the third focus detection pixels 302LL and 302LR. In some cases, the focus detection signal can be preferably output. The fifth focus detection pixels 302LNL and 302LNR correspond to the first focus detection pixels 302NL and 302NR, respectively, and the division center of the aperture provided in the light shielding member 35 is aligned with the division line 44N of the first focus detection pixels 302NL and 302NR. , and the dividing line 44S in the second focus detection pixels 302SL and 302SR. In other words, the exit pupil of the imaging optical system 110 is positioned closer than the positions assumed by the first focus detection pixels 302NL and 302NR and farther than the positions assumed by the second focus detection pixels 302SL and 302SR. In some cases, the focus detection signal can be preferably output.

As described above, the image sensor 210 includes five types of focus detection pixels (first focus detection pixels 302NL and 302NR, second focus detection pixels 302SL and 302SR, third focus detection pixels 302LL and 302LR, and fourth focus detection pixels 302SNL). , 302SNR, fifth focus detection pixels 302LNL, 302LNR), and these five types of focus detection pixels have different assumed exit pupil positions. That is, they correspond to different imaging optical systems 110 respectively. The position of the exit pupil changes, for example, when the interchangeable lens 100 is replaced with a different type, or when the zoom position of a so-called zoom lens with a variable focal length is changed. With this, a focus detection signal can be reliably obtained from any focus detection pixel regardless of the position of the exit pupil.

Next, the arrangement of the various types of focus detection pixels described above will be described. FIG. 7 is a plan view schematically showing the imaging surface 20 (that is, the imaging screen) of the imaging element 210. As shown in FIG. Now, consider five areas obtained by dividing the imaging plane 20 into five equal parts in the horizontal direction. The individual regions each have a rectangular outline with long sides parallel to the vertical line OX. Of these five areas, the area including the center of the imaging plane 20 is defined as a first area 60a. Two regions adjacent to the first region 60a are defined as second regions 60b. Furthermore, the remaining two regions adjacent to the left and right ends of the imaging surface 20 are defined as third regions 60c. In this embodiment, a plurality of focus detection pixel rows 61 in which focus detection pixels are arranged in a line in the horizontal direction (X-axis direction) are provided in the first area 60a, the second area 60b, and the third area 60c.

The second area 60b has a longer distance from the optical axis of the imaging optical system 110 in the horizontal direction (X-axis direction) of the drawing than the first area 60a. That is, the second area 60b is an area having a higher image height than the first area 60a. The third area 60c has a longer distance from the optical axis of the imaging optical system 110 in the horizontal direction (X-axis direction) than the first area 60a and the second area 60b. That is, the third area 60c is an area having a higher image height than the first area 60a and the second area 60b.

FIG. 8 shows an enlarged view of part of the first region 60a. In FIG. 8, letters "R", "G", and "B" represent imaging and focus detection pixels 301 having red, green, and blue color filters 32, respectively, and letters "NL" and "NR". Letters represent first focus detection pixels 302NL and 302NR, respectively.

As shown in FIG. 8, in the focus detection pixel row 61N in the first region 60a, the first focus detection pixels 302NL and 302NR are alternately arranged at regular intervals d along the horizontal direction (X-axis direction). It is For example, from left to right, a first focus detection pixel 302NL, a plurality of imaging and focus detection pixels 301a, a first focus detection pixel 302NR, a plurality of imaging and focus detection pixels 301a, a first focus detection pixel 302NL, . The pixels 30 are arranged as follows. That is, in the first region 60a, part of the imaging and focus detection pixels 301 are replaced with the first focus detection pixels 302NL and 302NR.

As shown in FIG. 7, more focus detection pixel rows 61 are provided in the second region 60b than in the first region 60a. FIG. 9 shows an enlarged view of part of the second region 60b. In FIG. 9, the second focus detection pixels 302SL, 302SR, and the third focus detection pixels 302LL, 302LR are represented by characters "SL", "SR", "LL", and "LR", respectively. A plurality of three types of focus detection pixel rows 61, a focus detection pixel row 61N, a focus detection pixel row 61S, and a focus detection pixel row 61L, are provided in the second region 60b.

In the focus detection pixel row 61N, first focus detection pixels 302NL and 302NR are alternately arranged at regular intervals d along the horizontal direction (X-axis direction). In the focus detection pixel row 61S, second focus detection pixels 302SL and 302SR are alternately arranged at regular intervals d along the horizontal direction (X-axis direction). In the focus detection pixel row 61L, the third focus detection pixels 302LL and 302LR are alternately arranged at regular intervals d along the horizontal direction (X-axis direction). That is, in the second region 60b, part of the imaging and focus detection pixels 301 are replaced with first focus detection pixels 302NL and 302NR, second focus detection pixels 302SL and 302SR, and third focus detection pixels 302LL and 302LR. there is

As shown in FIG. 7, the third region 60c has more focus detection pixel rows 61 than the second region 60b. FIG. 10 shows an enlarged view of part of the third region 60c. Note that in FIG. 10, the fourth focus detection pixels 302SNL, 302SNR, and the fifth focus detection pixels 302LNL, 302LNR are represented by characters "SNL", "SNR", "LNL", and "LNR", respectively. In the third region 60c, there are five types of focus detection in total: a focus detection pixel row 61N, a focus detection pixel row 61S, a focus detection pixel row 61L, a focus detection pixel row 61SN, and a focus detection pixel row 61LN. A plurality of pixel columns 61 are provided, respectively.

In the focus detection pixel row 61SN, fourth focus detection pixels 302SNL and 302SNR are alternately arranged at regular intervals d along the horizontal direction (X-axis direction). In the focus detection pixel row 61LN, fifth focus detection pixels 302LNL and 302LNR are alternately arranged at regular intervals d along the horizontal direction (X-axis direction). That is, in the third region 60c, part of the imaging and focus detection pixels 301 are the first focus detection pixels 302NL and 302NR, the second focus detection pixels 302SL and 302SR, the third focus detection pixels 302LL and 302LR, and the fourth focus. Detecting pixels 302SNL and 302SNR, and fifth focus detecting pixels 302LNL and 302LNR.

Next, focus detection processing by the first focus detection section 221 and the second focus detection section 222 will be described. At the start of focus detection processing, one focus detection area is set in advance on the photographic screen. For example, the focus detection area may be set manually by the user using an operation member such as a button (not shown), or may be automatically set by the body CPU 220 by known main subject recognition processing such as face recognition.

In the focus detection process, first, the second focus detection unit 222 performs focus detection calculation based on focus detection signals output from the focus detection pixels 302 in the focus detection area. This focus detection calculation is more suitable for detection of large defocus, that is, a state in which the focus is largely out of focus, compared to the focus detection calculation performed by the first focus detection section 221 (details will be described later). Therefore, in the following description, the focus detection calculation performed by the second focus detection section 222 will be referred to as focus detection calculation for large defocus.

When the second focus detection section 222 detects a defocus amount equal to or greater than a predetermined amount, that is, when large defocus is detected, the focus adjustment section 230 drives the focusing lens 112 based on the detection result. On the other hand, when a defocus amount less than the predetermined amount is detected, that is, when the imaging optical system 110 is in focus to some extent, the first focus detection unit 221 detects the image pickup and focus detection pixels in the focus detection area. A focus detection calculation is performed based on the focus detection signal output from 301 . Then, the focus adjustment section 230 drives the focusing lens 112 based on the detection result. Here, the focus detection calculation performed by the first focus detection section 221 is more suitable for focus detection when the defocus is not large compared to the focus detection calculation performed by the second focus detection section 222 (details will be described later). Therefore, in the following description, the focus detection calculation performed by the first focus detection section 221 is referred to as focus detection calculation for small defocus.

The focus detection calculation for large defocus performed by the second focus detection unit 222 will be described below. The second focus detection section 222 first selects the focus detection pixel row 61 according to the position of the exit pupil of the imaging optical system 110 from the vicinity of the focus detection area. For example, if the focus detection area is near the center of the photographic screen and only the focus detection pixel row 61N exists in that vicinity, that focus detection pixel row 61N is inevitably selected.

On the other hand, when the focus detection area is located away from the center of the photographing screen and the three focus detection pixel rows 61L, 61N, and 61S are present in the vicinity thereof, the position of the exit pupil of the imaging optical system 110 , one focus detection pixel row 61 is selected from among them. Specifically, when the exit pupil of the imaging optical system 110 is at a relatively far position (at a position farther than a predetermined distance), the focus detection pixel row 61L is selected. Conversely, when the exit pupil of the imaging optical system 110 is relatively close (within a predetermined distance), the focus detection pixel array 61S is selected. If it is neither (it is in an intermediate position), the focus detection pixel row 61N is selected.

Next, the second focus detection section 222 acquires focus detection signals from the focus detection pixels in the selected focus detection pixel row 61 . For example, if the focus detection pixel row 61N is selected, the first focus detection pixels 302NL and 302NR are arranged in a line within the focus detection pixel row 61N. The second focus detection unit 222 outputs an output signal in which the outputs of the many first focus detection pixels 302NL (light reception outputs of the photoelectric conversion unit 34) are arranged, and the outputs of the many first focus detection pixels 302NR (photoelectric conversion unit 34). A pair of output signals obtained by arranging the received light outputs) is a pair of focus detection signals. Then, correlation calculation is performed to calculate the phase difference between the pair of focus detection signals, and the defocus amount is calculated. Since such calculation is well known, the explanation is omitted.

The reason why the focus detection calculation performed by the second focus detection unit 222 is suitable for focus detection at the time of large defocus is that the photoelectric conversion units 34 of the focus detection pixels 302 are shielded by the light shielding member 35 except for a part. It depends. When the imaging optical system 110 is largely out of focus (i.e., when the defocus amount is very large), the focus detection signal obtained from the imaging and focus detection pixel 301 is a gentle signal with unclear contrast. Become. It is difficult to accurately detect the phase difference of such signals by correlation calculation.

On the other hand, in the photoelectric conversion unit 34 of the focus detection pixel 302, incident light is restricted by the light shielding member 35, and the focus detection direction (X-axis direction) of the range where the light flux that has passed through the imaging optical system 110 is incident. , is smaller than the width in the same direction of the photoelectric conversion units 34L and 34R of the imaging/focus detection pixel 301 .

In general, when the aperture 130 of the imaging optical system 110 is set to a small aperture, the depth of field becomes deep and a subject image with a small amount of blur can be obtained. . That is, even when the imaging optical system 110 is largely out of focus (that is, when the defocus amount is extremely large), the focus detection signals obtained from the focus detection pixels 302 are output from the imaging and focus detection pixels 301. Compared to the obtained focus detection signal, the signal has a higher contrast (more steep and more accurately represents the original subject image). With such a signal, it is easier to perform phase difference detection by correlation calculation than with the focus detection signal obtained from the imaging/focus detection pixel 301 . Therefore, even when the focus is greatly out of focus, accurate focus detection calculation can be performed compared to the imaging and focus detection pixel 301 .

As described above, the second focus detection unit 222 selects an appropriate focus detection pixel array 61 according to the position of the exit pupil of the imaging optical system 110. Therefore, the light flux from the exit pupil is rejected and focus detection is performed. will not interfere with In the first region 60a, even if the exit pupil of the imaging optical system 110 is far, the incident angle of the light flux from the exit pupil in the X-axis direction is Since it does not become so large, even the focus detection pixel row 61N does not reject the light flux from the exit pupil, and the focus detection pixel row 61N alone can sufficiently cope with this. Therefore, only the focus detection pixel row 61N is arranged in the first area 60a. For the same reason, fewer types of focus detection pixels are arranged in the second region 60b than in the third region 60c.

Next, focus detection calculation for small defocus performed by the first focus detection unit 221 will be described. The first focus detection unit 221 first acquires focus detection signals from the imaging and focus detection pixels 301 in the vicinity of the focus detection area. For example, a large number of imaging and focus detection pixels 301 arranged horizontally in the vicinity of the focus detection area are selected. Then, an output signal in which the light reception outputs of the photoelectric conversion units 34L of the selected imaging and focus detection pixels 301 are arranged, an output signal in which the light reception outputs of the photoelectric conversion units 34R of the imaging and focus detection pixels 301 are arranged, is a pair of focus detection signals. The first focus detection section 221 performs correlation calculation to calculate the phase difference between the pair of focus detection signals and calculates the defocus amount. Since such calculation is well known, the explanation is omitted.

Unlike the photoelectric conversion unit 34 of the focus detection pixel 302, the photoelectric conversion units 34L and 34R of the imaging and focus detection pixel 301 are not limited in the amount of incident light. Therefore, the amount of light photoelectrically converted is larger than that of the focus detection pixels 302 . That is, the signal amount of the focus detection signal is larger than that of the focus detection pixel 302 . Therefore, when the defocus amount is small to some extent, the defocus amount obtained by the second focus detection section 222 through focus detection calculation is more accurate than the defocus amount obtained by the first focus detection section 221 through focus detection calculation. is good. Therefore, in this embodiment, focus adjustment is performed based on the result of focus detection by the first focus detection section 221 during small defocus.

FIG. 11 is a flow chart of control processing executed by the body CPU 220 . When the camera body 200 is powered on, the body CPU 220 reads a control program including this control process from the ROM 240 and starts executing it.

First, in step S10, the body CPU 220 starts the periodic operation of the imaging device 210, that is, the readout of imaging signals at predetermined time intervals (for example, 1/60th of a second) for creating a live view image. In step S20, the body CPU 220 determines whether or not a predetermined automatic focus adjustment operation (for example, a release switch half-press operation) has been performed. If the automatic focusing operation has not been performed, body CPU 220 advances the process to step S30.

In step S<b>30 , the body CPU 220 reads imaging signals for creating a live view image from the imaging and focus detection pixels of the imaging device 210 . The imaging signal read here is a signal for creating a live view image, and it is not necessary to read signals from all the imaging and focus detection pixels. For example, thinning readout is performed to read every three pixels. In step S<b>40 , body CPU 220 updates the live view image displayed on display device 250 . In other words, a live view image is created and displayed on the display device 250 based on the imaging signal read out in step S30. Thereafter, body CPU 220 advances the process to step S20.

On the other hand, in step S20, if the automatic focusing operation has not been performed, body CPU 220 advances the process to step S50. In step S50, body CPU 220 executes autofocus (AF) processing, which will be described later. In step S60, the body CPU 220 determines whether or not a predetermined release operation (for example, a release switch full-press operation) has been performed. If the release operation has not been performed, body CPU 220 advances the process to step S70.

In step S<b>70 , the body CPU 220 reads imaging signals for creating a live view image from the imaging/focus detection pixels of the imaging device 210 . In step S<b>80 , body CPU 220 updates the live view image displayed on display device 250 . In other words, a live view image is created and displayed on the display device 250 based on the imaging signal read in step S70. Thereafter, body CPU 220 advances the process to step S20.

On the other hand, if the release operation has been performed in step S60, body CPU 220 advances the process to step S90. In step S<b>90 , the body CPU 220 reads imaging signals from the imaging/focus detection pixels 301 of the imaging device 210 . The imaging signal read here is a signal of recorded image data (main image data). Since it is desirable that the recorded image data have as high a quality as possible, signals are read out from all the imaging and focus detection pixels 301 . In step S<b>100 , the body CPU 220 interpolates the focus detection pixels 302 . In other words, since no imaging signal can be obtained from the position where the focus detection pixel 302 exists, the imaging signal that should be obtained from that position (if the imaging and focus detection pixel 301 exists at that position) is are generated in a pseudo manner based on the image pickup signals obtained from the image pickup and focus detection pixels 301 of .

In step S110, body CPU 220 creates recording image data and stores it in a storage medium (eg, memory card, etc.) not shown. In step S120, the body CPU 220 determines whether or not a predetermined power-off operation (for example, pressing the power switch) has been performed. If the power off operation has not been performed, body CPU 220 advances the process to step S20. On the other hand, if the power-off operation has been performed, the body CPU 220 ends the processing of FIG.

FIG. 12 is a flowchart of AF processing called from step S30 in FIG. First, in step S200, the second focus detection unit 222 selects one focus detection pixel row from the focus detection pixel rows in the vicinity of the focus detection area based on the current information of the imaging optical system 110 (for example, the exit pupil position). do. For example, when the focus detection area is located in the third region 60c and the exit pupil of the imaging optical system 110 is somewhat distant, the focus detection pixel row 61L is selected. Information on the current imaging optical system 110 may be received by the body CPU 220 from the lens CPU 120 through data communication between the lens CPU 120 and the body CPU 220 .

In step S210, the second focus detection unit 222 reads focus detection signals from the focus detection pixels 302 included in the focus detection pixel row selected in step S200. In step S220, the second focus detection unit 222 performs focus detection calculation based on the focus detection signal read out in step S210, that is, focus detection calculation for large defocus.

In step S230, the second focus detection unit 222 determines whether or not a defocus amount equal to or greater than a predetermined amount, that is, a large defocus is detected by the focus detection calculation for large defocus performed in step S220. If a defocus amount equal to or greater than the predetermined amount has been detected, the second focus detection section 222 advances the process to step S240. In step S240, the focus adjustment unit 230 drives the focusing lens 112 based on the defocus amount obtained by the focus detection calculation for large defocus. After that, the second focus detection unit 222 advances the process to step S200.

On the other hand, if a defocus amount equal to or greater than a predetermined amount is not detected in step S230 (when the detected defocus amount is less than a predetermined amount, or when the defocus amount cannot be detected, etc.), the second The focus detection unit 222 advances the process to step S250. In step S<b>250 , the first focus detection unit 221 reads light reception signals (light reception outputs) from the imaging and focus detection pixels 301 . As described above, the signal read here is a signal that can be treated as an imaging signal and also as a focus detection signal.

In step S<b>260 , body CPU 220 updates the live view image displayed on display device 250 . That is, the signal read out in step S250 is treated as an imaging signal, and a live view image is created and displayed on the display device 250. FIG. In step S270, the first focus detection unit 221 selects one pixel row composed of imaging and focus detection pixels 301 arranged in the focus detection direction (X-axis direction) from the vicinity of the focus detection area. In step S280, the first focus detection unit 221 uses the signal corresponding to the pixel row selected in step S270 among the signals read out in step S250 as a focus detection signal, and performs focus detection calculation based on the focus detection signal, that is, a small focus detection signal. Perform focus detection calculation for focus.

In step S290, body CPU 220 determines whether or not the focus detection calculation for small defocus performed in step S280 has succeeded. For example, when phase difference detection cannot be performed and focus detection fails due to reasons such as low contrast of the subject image, body CPU 220 advances the process to step S300. In step S300, the body CPU 220 determines whether or not the most recent focus detection calculation for large defocus performed in step S220 was successful. If the defocus amount has been successfully calculated by the most recent focus detection calculation for large defocus, the body CPU 220 advances the process to step S310.

In step S310, the focus adjustment unit 230 drives the focusing lens 112 based on the defocus amount obtained by the focus detection calculation for large defocus. Thereafter, body CPU 220 advances the process to step S200.

In step S300, if the most recent focus detection calculation for large defocus has failed to calculate the defocus amount, body CPU 220 advances the process to step S320. In step S320, the focus adjustment unit 230 performs so-called search drive (scan drive) to move the focusing lens over a certain range. Thereafter, body CPU 220 advances the process to step S200.

In step S290, if the focus detection calculation for small defocus performed in step S280 has succeeded, the body CPU 220 advances the process to step S330. In step S330, body CPU 220 determines whether imaging optical system 110 is in focus, that is, whether the defocus amount detected in step S280 is sufficiently small (smaller than a predetermined threshold value). do. If it is not in focus, that is, if the defocus amount is equal to or greater than the predetermined threshold value, body CPU 220 advances the process to step S340. In step S340, the focus adjustment unit 230 drives the focusing lens 112 based on the defocus amount obtained by the focus detection calculation for small defocus. Thereafter, body CPU 220 advances the process to step S250. The reason why the process proceeds to step S250 instead of step S200 is that it is clear that the subject is already in focus to some extent (it is not in a large defocus state). If it is in focus in step S330, that is, if the defocus amount is smaller than the predetermined threshold value, body CPU 220 ends the AF processing. As described above, in the AF processing of the present embodiment, focus detection calculation for large defocus is first performed, and when a large defocus state is detected, focus detection for small defocus, which is likely to fail, The lens is driven based on the result of focus detection calculation for large defocus without performing calculation.

According to the camera system according to the first embodiment described above, the following effects are obtained. (1) The image sensor 210 includes a plurality of imaging and focus detection pixels 301 into which incident light enters a predetermined range, and a plurality of types of focus detection pixels in which incident light enters a range smaller than the imaging and focus detection pixels 301. A pixel 302 is arranged. The image sensor 210 includes a first region 60a in which one type of focus detection pixels 302 is arranged, and a second region 60a having a higher image height than the first region 60a and a second region 60a in which more types of focus detection pixels 302 than the first region 60a are arranged. region 60b. Since this is done, focus detection can be appropriately performed in both a large defocus state and a small defocus state.

(2) A plurality of types of focus detection pixels 302 have apertures smaller in width in a predetermined direction than the imaging and focus detection pixels 301 . Since this is done, focus detection can be appropriately performed in both a large defocus state and a small defocus state.

(3) The first focus detection pixels 302NR and 302NL corresponding to the first exit pupil position are arranged in the first region 60a, and the first focus detection pixels 302NR and 302NL and the first focus detection pixels 302NR and 302NL are arranged in the second region 60b. Second focus detection pixels 302SR and 302SL corresponding to a second exit pupil position different from the exit pupil position of . Since this is done, even if the position of the exit pupil changes due to, for example, the interchangeable lens 100 being replaced with another type, focus detection can be performed appropriately.

(4) The distance in the X-axis direction from the optical axis of the imaging optical system 110 (the center of the imaging plane 20) to the first region 60a is the optical axis of the imaging optical system 110 in the same direction (the center of the imaging plane 20) to the second region 60b. Since this is done, only the minimum number of focus detection pixels 302 can be arranged at positions where there is a low possibility that the subject light will be blocked, and the image quality of the captured image data will be improved.

(5) The imaging element 210 corresponds to the imaging and focus detection pixels 301 in which incident light enters a predetermined range, and the first exit pupil position in which the incident light enters a range smaller than the imaging and focus detection pixels 301. First focus detection pixels 302NR and NL, and a second focus detection pixel 302SR corresponding to a second exit pupil position different from the first exit pupil position in which incident light enters a range smaller than the imaging and focus detection pixel 301. , SL. The image sensor 210 includes a first region 60a in which first focus detection pixels 302NR and NL are arranged, and first focus detection pixels 302NR and NL and second focus detection pixels 302SR and SL having an image height higher than that of the first region 60a. and a second region 60b in which is arranged. This makes it easier to manufacture the image sensor 210 than when two photoelectric conversion units 34 are provided in the single focus detection pixel 302 .

(6) The image sensor 210 includes a first focus detection pixel 302NR and a second focus detection pixel 302SR that receive light from one of the pair of exit pupils, and a first focus that receives light from the other of the pair of exit pupils. a detection pixel 302NL and a second focus detection pixel 302SL. Since this is done, there is no need to deform the photoelectric conversion units 34 individually, and the manufacturing cost of the imaging element 210 is reduced.

(7) The image sensor 210 includes third focus detection pixels LR and LL, to which incident light is incident in a range smaller than that of the imaging and focus detection pixels 301, and first focus detection pixels whose image height is higher than that of the second region 60b. 302NR, NL, second focus detection pixels 302SR, SL, and third focus detection pixels 302LR, LL are arranged in a third region 60c. Since this is done, finer focus detection can be performed according to the position of the exit pupil.

(8) A plurality of types of focus detection pixels 302 are arranged along the X-axis direction. With this arrangement, phase difference detection type focus detection can be performed.

(9) The first focus detection unit 221 performs focus detection based on the focus detection signal output from the imaging/focus detection pixel 301 . The second focus detection unit 222 performs focus detection based on the focus detection signals (photoelectric conversion signals) output from the first focus detection pixels 302NR and 302NL when the exit pupil of the imaging optical system 110 is at the first position. When the exit pupil of the imaging optical system 110 is at the second position, focus detection is performed based on focus detection signals output from the second focus detection pixels 302SR and 302SL. Thus, regardless of whether the exit pupil of imaging optics 110 is at the first or second position, regardless of whether it is in a small defocus state or a large defocus state, it is always in proper focus. Detection can be performed.

(10) The focus adjustment unit 230 adjusts the focus of the imaging optical system 110 based on the result of focus detection when the result of focus detection by the second focus detection unit 222 indicates defocus of a predetermined amount or more. If the result of focus detection by the second focus detection unit 222 does not indicate defocus of a predetermined amount or more, focus adjustment of the imaging optical system 110 is performed based on the result of focus detection by the first focus detection unit 221. conduct. Since this is done, there is no need to operate the first focus detection section 221 in the large defocus state, the processing load on the body CPU 220 can be reduced, and power consumption can be reduced.

(Second embodiment)
The camera system according to the second embodiment has the same configuration as the camera system according to the first embodiment, but the content of the AF processing executed by the body CPU 220 is different from that of the first embodiment. is different from The AF processing in the second embodiment will be described below.

FIG. 13 is a flowchart of AF processing called from step S50 of FIG. 11 in this embodiment. First, in step S<b>400 , the first focus detection unit 221 reads light reception signals (light reception outputs) from the imaging and focus detection pixels 301 . As described above, the signal read here is a signal that can be treated as an imaging signal and also as a focus detection signal.

In step S<b>410 , body CPU 220 updates the live view image displayed on display device 250 . That is, the signal read out in step S400 is treated as an imaging signal, and a live view image is created and displayed on the display device 250. FIG.

In step S415, the first focus detection unit 221 selects one pixel row composed of imaging and focus detection pixels 301 arranged in the focus detection direction (X-axis direction) from the vicinity of the focus detection area. In step S420, the first focus detection unit 221 uses the signal corresponding to the pixel row selected in step S415 among the signals read out in step S400 as a focus detection signal, and performs focus detection calculation based on the focus detection signal, that is, a small focus detection signal. Perform focus detection calculation for focus.

In step S430, body CPU 220 determines whether or not the focus detection calculation for small defocus performed in step S420 has succeeded. For example, when the focus detection fails because the imaging optical system 110 is largely out of focus, that is, in a large defocus state, the body CPU 220 advances the process to step S440.

In step S440, the second focus detection unit 222 selects one focus detection pixel row from the focus detection pixel rows in the vicinity of the focus detection area based on the current information of the imaging optical system 110 (e.g. exit pupil position). . In step S450, the second focus detection unit 222 reads focus detection signals from the focus detection pixels 302 included in the focus detection pixel row selected in step S440. In step S460, the second focus detection unit 222 performs focus detection calculation based on the focus detection signal read out in step S450, that is, focus detection calculation for large defocus.

In step S470, body CPU 220 determines whether or not the focus detection calculation for large defocus performed in step S460 was successful. If focus detection fails, body CPU 220 advances the process to step S490. In step S490, the focus adjustment unit 230 performs so-called search drive (scan drive) to move the focusing lens over a certain range. Thereafter, body CPU 220 advances the process to step S400.

On the other hand, in step S470, if the calculation of the defocus amount by the focus detection calculation for large defocus has succeeded, the body CPU 220 advances the process to step S480. In step S480, the focus adjustment unit 230 drives the focusing lens 112 based on the defocus amount obtained by the focus detection calculation for large defocus. Thereafter, body CPU 220 advances the process to step S400.

In step S430, if the calculation of the defocus amount by the focus detection calculation for small defocus has succeeded, the body CPU 220 advances the process to step S500. In step S500, body CPU 220 determines whether imaging optical system 110 is in focus, that is, whether the defocus amount detected in step S420 is sufficiently small (smaller than a predetermined threshold value). do. If it is not in focus, that is, if the defocus amount is equal to or greater than the predetermined threshold value, body CPU 220 advances the process to step S510. In step S510, the focus adjustment unit 230 drives the focusing lens 112 based on the defocus amount obtained by the focus detection calculation for small defocus. Thereafter, body CPU 220 advances the process to step S400. On the other hand, if it is in focus in step S500, that is, if the defocus amount is smaller than the predetermined threshold value, body CPU 220 ends the processing shown in FIG. As described above, in the AF processing of this embodiment, focus detection calculation for small defocus is first performed, and only when this fails, focus detection calculation for large defocus is performed.

According to the camera system according to the second embodiment described above, the following effects are obtained. (1) When focus detection by the first focus detection unit 221 is successful, the focus adjustment unit 230 adjusts the focus of the imaging optical system 110 based on the result of the focus detection. If the detection fails, focus adjustment of the imaging optical system 110 is performed based on the result of focus detection by the second focus detection section 222 . With this configuration, the focus detection by the second focus detection section 222 is performed only at the time of large defocus, so that the processing load on the body CPU 220 can be reduced and the power consumption can be reduced.

(Third Embodiment)
The camera system according to the third embodiment has the same configuration as the camera system according to the first embodiment, but instead of the image sensor 210, it has an image sensor 210a with a different structure. It differs from the first embodiment in that the The imaging element 210a in the third embodiment will be described below.

FIG. 14 is a perspective view schematically showing the structure of an imaging device 210a according to the third embodiment. The imaging device 210 a has a microlens array 211 and a photoelectric conversion array 212 . The microlens array 211 has a plurality of microlenses 31 arranged two-dimensionally in a square. The photoelectric conversion array 212 has a plurality of photoelectric conversion units 34 arranged in a two-dimensional square. Note that the array of the plurality of microlenses 31 does not have to be a square array.

The microlens array 211 is arranged at a position separated from the light receiving surface of the photoelectric conversion array 212 by the focal length f of the microlenses 31 . In other words, the microlens array 211 and the photoelectric conversion array 212 are arranged so that the focal position of the microlens 31 and the light receiving surface of the photoelectric conversion array 212 match.

In this embodiment, the diameter of one microlens 31 is larger than the width of one photoelectric conversion unit 34 . That is, one microlens 31 covers a plurality of photoelectric conversion units 34 . Subject light that has passed through one microlens 31 enters a plurality of photoelectric conversion units 34 corresponding to that microlens 31 . As illustrated in FIG. 14 , a plurality of photoelectric conversion units 34 are included in a range 215 where light passing through one microlens 31 is incident.

The imaging element 210a has a plurality of pixels 30. As shown in FIG. The pixels 30 include two types of pixels: imaging and focus detection pixels 301 used for both imaging and focus detection, and focus detection pixels 302 used only for focus detection. These two types of pixels are described below.

FIG. 15 is a cross-sectional view schematically showing the imaging/focus detection pixel 301 and the focus detection pixel 302. As shown in FIG. Note that FIG. 15 schematically illustrates a cross section of the central portion of the imaging surface of the imaging element 210a. In the first embodiment, one pixel 30 had one microlens 31 . In contrast, in this embodiment, a plurality of pixels 30 share one microlens 31 . In other words, in the present embodiment, the microlens 31 included in one pixel 30 and the microlens 31 included in another pixel 30 may be the same microlens 31 .

The imaging and focus detection pixel 301 has a microlens 31 , a color filter 32 , and a photoelectric conversion section 34 . The incident light that has entered the microlens 31 enters the photoelectric conversion section 34 via the color filter 32 . The color filter 32 is formed for each pixel so as to transmit red, blue, or green light and not transmit other light. The color filters 32 of the imaging and focus detection pixels 301 are configured to form a so-called Bayer array. The imaging/focus detection pixel 301 outputs the photoelectric conversion signal output from the photoelectric conversion unit 34 .

Note that the imaging and focus detection pixel 301 according to the present embodiment is distant from the center of the imaging plane, similarly to the imaging and focus detection pixel 301 according to the first embodiment shown in FIG. , the position of the optical axis 41 of the microlens 31 and the center of the photoelectric conversion unit 34 are separated, and the distance increases as the distance from the center of the imaging surface increases. Since this point is the same as the first embodiment, illustration and description are omitted.

The focus detection pixels 302 are the same as in the first embodiment except that the microlenses 31 are shared among the multiple pixels 30 . That is, the focus detection pixel 302 has a microlens 31 , a color filter 32 , a photoelectric conversion section 34 and a light blocking member 35 . Part of the incident light that has entered the microlens 31 passes through the color filter 32 and is not blocked by the light shielding member 35 , and enters the photoelectric conversion unit 34 .

Also in this embodiment, as in the first embodiment, the focus detection pixels 302 include first focus detection pixels 302NL and 302NR, second focus detection pixels 302SL and 302SR, and third focus detection pixels 302LL and 302LR. , fourth focus detection pixels 302SNL and 302SNR, and fifth focus detection pixels 302LNL and 302LNR. In the first embodiment, these focus detection pixels have different widths of apertures, but in the present embodiment, the widths of the apertures are the same.

FIG. 16 is an enlarged plan view of a portion of the first region 60a (FIG. 7) of the imaging element 210a. In FIG. 16, letters "R", "G", and "B" represent imaging pixels 303 having red, green, and blue color filters 32, respectively, and letters "NL" and "NR" They represent first focus detection pixels 302NL and 302NR, respectively.

In the first embodiment, in the focus detection pixel row 61N in the first region 60a, the first focus detection pixels 302NL and 302NR are arranged alternately at regular intervals d along the horizontal direction (X-axis direction). were arranged. In this embodiment, instead of the focus detection pixel array 61N, a microlens array 610N in which the microlenses 31 including the focus detection pixels 302 are arranged in a line in the horizontal direction (X-axis direction) is considered. First focus detection pixels 302NL and 302NR are alternately arranged at regular intervals (every other pixel in FIG. 16) in the microlenses 31 included in the microlens row 610N in the first region 60a.

For example, one first focus detection pixel 302NL is included in a total of 36 pixels 30 of 6×6 having the leftmost microlens 31a in FIG. A focus detection pixel 302 is not included in a total of 36 pixels 30 of 6×6 having microlenses 31b on the right. One first focus detection pixel 302NR is included in a total of 36 pixels 30 of 6×6 having a microlens 31c one next to the right.

The pair of first focus detection pixels 302NL and 302NR are arranged point-symmetrically with respect to the principal ray from the assumed exit pupil position within each microlens 31 . For example, in the microlens array 610N shown in FIG. 16, the position of the principal ray from the assumed exit pupil position is indicated by a circle LP. Focusing on each microlens 31, the first focus detection pixel 302NL and the first focus detection pixel 302NR are arranged point-symmetrically with respect to the circle LP. Specifically, the first focus detection pixel 302NL is arranged just below the circle LP, and the first focus detection pixel 302NR is arranged just above the circle LP.

FIG. 17 is an enlarged plan view of a portion of the second region 60b (FIG. 7) of the imaging device 210a. In FIG. 17, the second focus detection pixels 302SL, 302SR, and the third focus detection pixels 302LL, 302LR are represented by characters "SL", "SR", "LL", and "LR", respectively. In the second region 60b, a plurality of three types of microlens rows 61, ie, a microlens row 610L, a microlens row 610N, and a microlens row 610S are provided.

First focus detection pixels 302NL and 302NR are alternately arranged at regular intervals (every other pixel in FIG. 17) in the microlenses 31 included in the microlens row 610N. The second focus detection pixels 302SL and 302SR are alternately arranged at regular intervals (every other pixel in FIG. 17) in the microlenses 31 included in the microlens row 610S. The microlenses 31 included in the microlens array 610L are alternately arranged with third focus detection pixels 302LL and 302LR at regular intervals (every other pixel in FIG. 17).

The pair of second focus detection pixels 302SL and 302SR and the pair of third focus detection pixels 302LL and 302LR are arranged point-symmetrically with respect to the principal ray from the assumed exit pupil position within each microlens 31. . For example, in the microlens array 610S shown in FIG. 17, the position of the principal ray from the assumed exit pupil position is indicated by a circle LP. Focusing on each microlens 31, the second focus detection pixel 302SL and the second focus detection pixel 302SR are arranged point-symmetrically with respect to the circle LP. Specifically, the second focus detection pixel 302SL is arranged just below the circle LP, and the second focus detection pixel 302SR is arranged just above the circle LP. The same applies to the third focus detection pixels 302LL and 302LR.

The first focus detection pixels 302NL and 302NR are arranged near the optical axis of the microlens 31 . On the other hand, the second focus detection pixels 302SL and 302SR are arranged at positions separated from the optical axis of the microlens 31 by a certain distance in the right direction of the drawing. Similarly, the third focus detection pixels 302LL and 302LR are arranged at a fixed distance from the optical axis of the microlens 31 in the left direction of the drawing (the direction opposite to the second focus detection pixels 302SL and 302SR).

As described above, in the present embodiment, the positions at which the focus detection pixels 302 are arranged are different depending on the assumed pupil position. That is, the focus detection pixels 302 are arranged at positions corresponding to the assumed pupil positions. For example, the light from the exit pupil position assumed by the first focus detection pixels 302NL and 302NR forms a spot image near the center of the microlens 31. placed in On the other hand, the second focus detection pixels 302SL and 302SR, which assume a short pupil position, form spots on the side closer to the optical axis of the image sensor 210a with respect to the optical axis of the microlens 31, that is, on the left side of FIG. The second focus detection pixels 302SL and 302SR are arranged on the right side of the optical axis of the microlens 31 . Conversely, the third focus detection pixels 302LL and 302LR are arranged on the left side of the optical axis of the microlens 31 .

FIG. 18 is an enlarged plan view of a portion of the third region 60c (FIG. 7) of the imaging device 210a. Note that in FIG. 18, the fourth focus detection pixels 302SNL, 302SNR, and the fifth focus detection pixels 302LNL, 302LNR are represented by characters "SNL", "SNR", "LNL", and "LNR", respectively. In the third region 60c, there are a plurality of each of five types of microlens rows 610: a microlens row 610S, a microlens row 610SN, a microlens row 610N, a microlens row 610LN, and a microlens row 610L. is provided.

First focus detection pixels 302NL and 302NR are alternately arranged at regular intervals (every other pixel in FIG. 18) in the microlenses 31 included in the microlens row 610N. The second focus detection pixels 302SL and 302SR are alternately arranged at regular intervals (every other pixel in FIG. 18) in the microlenses 31 included in the microlens row 610S. The microlenses 31 included in the microlens array 610L are alternately arranged with third focus detection pixels 302LL and 302LR at regular intervals (every other pixel in FIG. 18). Fourth focus detection pixels 302SNL and 302SNR are alternately arranged at regular intervals (every other pixel in FIG. 18) in the microlenses 31 included in the microlens row 610SN. Fifth focus detection pixels 302LNL and 302LNR are alternately arranged at regular intervals (every other pixel in FIG. 18) in the microlenses 31 included in the microlens row 610LN.

The pair of fourth focus detection pixels 302SNL and 302SNR and the pair of fifth focus detection pixels 302LNL and 302LNR are arranged point-symmetrically with respect to the principal ray from the assumed exit pupil position within each microlens 31. . For example, in the microlens array 610SN shown in FIG. 18, the position of the principal ray from the assumed exit pupil position is indicated by a circle LP. Focusing on each microlens 31, the fourth focus detection pixel 302SNL and the fourth focus detection pixel 302SNR are arranged point-symmetrically with respect to the circle LP. Specifically, the fourth focus detection pixel 302SNL is arranged just below the circle LP, and the fourth focus detection pixel 302SNR is arranged just above the circle LP. The same applies to the fifth focus detection pixels 302LNL and 302LNR.

The fourth focus detection pixels 302SNL and 302SNR are arranged at positions separated from the optical axis of the microlens 31 by a certain distance in the right direction of the paper surface. The distance from the optical axis of the microlens 31 is shorter than the second focus detection pixels 302SL and 302SR. Similarly, the fifth focus detection pixels 302LNL and 302LNR are arranged at a position a fixed distance away from the optical axis of the microlens 31 in the left direction of the drawing (the direction opposite to the fourth focus detection pixels 302SNL and 302SNR). The distance from the optical axis of the microlens 31 is shorter than that of the third focus detection pixels 302LL and 302LR.

By using the image sensor 210a configured as described above, an image of an arbitrary image plane (a so-called refocus image) within a predetermined range in the optical axis direction is synthesized from the imaging signals output from the imaging and focus detection pixels 301. , a so-called refocus function can be realized. The refocus function will be described below.

FIG. 19 is a cross-sectional view schematically showing a luminous flux from a light point P on the image plane S to be synthesized and the imaging element 210a. In FIG. 19, consider a light spot P provided on an image plane S to be synthesized. A spread angle θ of light from this light point P toward the image sensor 12 is defined by the size of the pupil of the imaging optical system 110 (that is, the aperture value of the imaging optical system 110). The aperture value of the microlens 31 is configured to be equal to or smaller than the aperture value of the imaging optical system 110 . Therefore, the luminous flux emitted from this light point P and incident on a certain microlens 31 does not spread outside the area covered by that microlens 31 .

Here, as shown in FIG. 19, if the luminous flux from the light point P is incident on five microlenses 31(1) to 31(5), these microlenses 31(1) to 31(5) By accumulating the amount of incident light (photoelectric conversion output of the photoelectric conversion units 34(1) to 34(5)) of the incident light beams 300(1) to 300(5) on the light receiving surface, the pupil from the light point P A limited amount of total incident light is obtained. That is, the amount of light of the light spot P (pixel to be synthesized) on the image plane S to be synthesized is obtained.

The body CPU 220 sets a plurality of light spots P on the designated image plane S, and specifies, for each light spot P, the microlens 31 on which the light flux from that light spot P is incident. The body CPU 220 specifies which photoelectric converter 34 the light flux from the light point P is incident on for each specified microlens 31 . The body CPU 220 calculates the pixel value of the light spot P by integrating the photoelectric conversion outputs of the identified photoelectric conversion units 34 . Note that when the specified photoelectric conversion unit 34 is the photoelectric conversion unit 34 of the focus detection pixel 302, instead of the photoelectric conversion output from the photoelectric conversion unit 34, the photoelectric conversion by the surrounding photoelectric conversion units 34 It is desirable to use a photoelectric conversion output obtained by performing an interpolation operation based on the output.

By the above processing, the image of the image plane S designated as the synthesis target is synthesized. The body CPU 220 can synthesize images of a plurality of different image planes with the imaging signal output from the imaging element 210a by one imaging. That is, images of a plurality of image planes can be obtained from one imaging result.

By the way, there are certain restrictions on the positions of the image planes that can be suitably synthesized while maintaining a certain resolution by the above processing. For example, it is known that combining image planes near the vertices of the microlenses 31 results in a lower resolution than combining image planes at other positions. In this way, there are restrictions on image plane positions that can be combined. Therefore, the body CPU 220 recognizes the main subject included in the imaging range by a well-known subject recognition technique or the like, and adjusts the main subject so that it is included in the range in which the main subject can be suitably synthesized (hereinafter simply referred to as the synthesizable range). , drives the focusing lens 112 . Focus adjustment in this embodiment refers to adjusting the position of the focusing lens 112 so that the main subject is included in the synthesizable range.

Next, focus detection calculation for small defocus performed by the first focus detection unit 221 will be described. The first focus detection unit 221 first acquires focus detection signals from the imaging and focus detection pixels 301 in the vicinity of the focus detection area. For example, a large number of microlenses 31 arranged horizontally in the vicinity of the focus detection area are selected. Then, for each of the selected microlenses 31, a signal obtained by adding the received light output of the photoelectric conversion unit 34 of the imaging and focus detection pixel 301 arranged on the left half of the microlens 31, and A signal is generated by adding the received light output of the photoelectric conversion unit 34 of the arranged imaging and focus detection pixel 301 . These pair of signals can be treated as a pair of focus detection signals, like the light receiving outputs of the photoelectric conversion units 34L and 34R in the first embodiment. The first focus detection section 221 performs correlation calculation to calculate the phase difference between the pair of focus detection signals and calculates the defocus amount. Since such calculation is well known, the explanation is omitted.

In the above description, the light reception outputs of the photoelectric conversion units 34 of the imaging and focus detection pixels 301 arranged in the left and right halves of the microlens 31 are added. A focus detection signal can be obtained as if the amount of incident light was limited. As the number of photoelectric conversion units 34 used for addition is reduced, the response to large defocus is improved, but on the other hand, the signal amount of the focus detection signal is reduced and the accuracy is deteriorated. Therefore, for example, when the defocus is small, it is desirable to add the received light outputs from many photoelectric conversion units 34 . On the other hand, by generating a pair of focus detection signals using only light reception outputs from two (a pair of) photoelectric conversion units 34, it is possible to cope with large defocus.

Furthermore, in the case of large defocus, there is a possibility that focus detection cannot be performed even with a pair of focus detection signals using only light reception outputs from two (a pair of) photoelectric conversion units 34 . In such a case, in the present embodiment, focus adjustment is performed using the result of focus detection calculation for large defocus performed by the second focus detection section 222 .

Next, the focus detection calculation for large defocus performed by the second focus detection section 222 will be described. The second focus detection unit 222 first selects the microlens array 610 according to the position of the exit pupil of the imaging optical system 110 from the vicinity of the focus detection area. For example, if the focus detection area is near the center of the photographing screen and only the microlens row 610N exists in that vicinity, that microlens row 610N is inevitably selected.

On the other hand, when the focus detection area is located away from the center of the imaging screen and the three microlens arrays 610S, 610N, and 610L are present in the vicinity thereof, the position of the exit pupil of the imaging optical system 110 One microlens row 610 is selected from among them. Specifically, when the exit pupil of the imaging optical system 110 is at a relatively far position (at a position farther than a predetermined distance), the microlens array 610L is selected. Conversely, when the exit pupil of the imaging optical system 110 is relatively close (within a predetermined distance), the microlens array 610S is selected. If it is neither (it is in an intermediate position), the microlens array 610N is selected.

Next, the second focus detection unit 222 acquires focus detection signals from the focus detection pixels 302 in the selected microlens array 610 . For example, if the microlens row 610N is selected, the first focus detection pixels 302NL and 302NR are arranged in a row within the microlens row 610N. The second focus detection unit 222 outputs an output signal in which the outputs of the many first focus detection pixels 302NL (light reception outputs of the photoelectric conversion unit 34) are arranged, and the outputs of the many first focus detection pixels 302NR (photoelectric conversion unit 34). A pair of output signals obtained by arranging the received light outputs) is a pair of focus detection signals. Then, correlation calculation is performed to calculate the phase difference between the pair of focus detection signals, and the defocus amount is calculated. Since such calculation is well known, the explanation is omitted.

Since the aperture of the pair of focus detection signals obtained here is restricted by the light shielding member 35, the pair of focus detection signals obtained by using only the light receiving outputs from the two (a pair of) photoelectric conversion units 34 described above can be obtained. Furthermore, it is a focus detection signal capable of coping with a large defocus.

According to the camera system according to the third embodiment described above, the following effects are obtained. (1) A focus detection pixel 302 and a plurality of imaging/focus detection pixels 301 to which light passing through a certain microlens 31 is incident, and a focus detection pixel 302 and a plurality of imaging/focus detection pixels 302 to which light that has passed through another microlens 31 is incident. A focus detection pixel 301 is provided. As a result, even in a so-called refocus camera, appropriate focus detection can be performed in both a large defocus state and a small defocus state.

The following modifications are also within the scope of the present invention, and it is also possible to combine one or more of the modifications with the above-described embodiments.

(Modification 1)
In the above-described embodiments, the light shielding member 35 having an opening with a predetermined width is provided in the focus detection pixel 302 . Thus, instead of providing the light blocking member 35, the width of the photoelectric conversion section 34 may actually be reduced.

FIG. 20A illustrates a first focus detection pixel 302NR' having a photoelectric conversion unit 34NR formed in accordance with the position and size of the opening 36NR instead of the light shielding member 35 having the opening 36NR.

Also, the first focus detection pixel 302NR and the first focus detection pixel 302NL may be a single pixel having a pair of photoelectric conversion units. That is, for one pixel, the photoelectric conversion unit 34 having the size corresponding to the opening 36NR is provided at the position corresponding to the opening 36NR, and the photoelectric conversion unit 34 having the size corresponding to the opening 36NL is provided at the position corresponding to the opening 36NL. may be provided to replace the first focus detection pixels 302NR and NL in the above-described embodiment. The same applies to the second to fifth focus detection pixels.

Alternatively, for one pixel, a pair of photoelectric conversion units 34L and 34R similar to the imaging and focus detection pixel 301 may be provided, and both openings 36NL and NR may be provided in the light blocking member 35. FIG. The same applies to the second to fifth focus detection pixels.

(Modification 3)
When the light shielding member 35 is provided in the focus detection pixel 302 , there is a possibility that the light flux that has not entered the photoelectric conversion unit 34 (the light flux that has entered the light shielding member 35 ) leaks into the adjacent imaging and focus detection pixel 301 . In order to prevent such stray light, an antireflection film may be provided on the surface of the light blocking member 35 . FIG. 20(b) illustrates a first focus detection pixel 302NR″ in which the antireflection film 37 is provided on the surface of the light shielding member 35. As shown in FIG.

(Modification 4)
The number of types of focus detection pixels 302, the number of arrangement, and the arrangement may differ from those in the above-described embodiment. Similarly, the number of types, number, shape, and arrangement pattern of the regions in which the focus detection pixels 302 are arranged, which are exemplified as the first region 60a, the second region 60b, and the third region 60c, are different from those in the above-described embodiment. good too.

FIG. 21(a) shows an example in which the first area 60a, the second area 60b, and the third area 60c are arranged in an arc shape. FIG. 21(b) shows an example in which the first region 60a, the second region 60b, and the third region 60c are concentrically arranged. As described above, various shapes and arrangement patterns of the regions where the focus detection pixels 302 are arranged are conceivable.

(Modification 5)
The shape of the pair of photoelectric conversion units 34R and 34L included in the imaging and focus detection pixel 301 may be different from that shown in FIG. 3(a). For example, it may be rectangular as shown in FIG. 22(a). Also, the focus detection direction is not limited to the X-axis direction, and may be, for example, the Y-axis direction. In this case, for example, as shown in FIG. 22B, a pair of photoelectric conversion units 34T and 34B divided in the Y-axis direction may be provided.

Furthermore, both the X-axis direction and the Y-axis direction can be set as focus detection directions. For example, as shown in FIG. 22C, four photoelectric conversion units 34a, 34b, 34c, and 34d are provided. At this time, by adding the light reception signals of the two photoelectric conversion units 34a and 34c arranged on the left side of the paper, a signal corresponding to the light reception signal of the photoelectric conversion unit 34L shown in FIG. 22(a) can be obtained. Further, by adding the light receiving signals of the two photoelectric conversion units 34a and 34b arranged on the upper side of the paper, a signal corresponding to the light receiving signal of the photoelectric conversion unit 34T illustrated in FIG. 22B can be obtained. Therefore, as shown in FIG. 22C, the imaging and focus detection pixel 301 is configured, and the widths of the four photoelectric conversion units 34a, 34b, 34c, and 34d in the X-axis direction and the Y-axis direction are reduced. If the focus detection pixel 302 having a portion is provided, both the X-axis direction and the Y-axis direction become focus detection directions.

As long as the features of the present invention are not impaired, the present invention is not limited to the above embodiments, and other forms conceivable within the scope of the technical idea of the present invention are also included within the scope of the present invention. .

REFERENCE SIGNS LIST 1 Camera system 100 Interchangeable lens 110 Imaging optical system 112 Focusing lens 120 Lens CPU 130 Aperture 200 Camera body 210 Imaging device 220 Body CPU 221 First Focus detection unit 222 Second focus detection unit 230 Focus adjustment unit 240 ROM 250 Display device 301, 301a, 301b Imaging and focus detection pixels 302 Focus detection pixels

Claims (11)

A first light shielding part that shields part of the light transmitted through the optical system and the first microlens, a first photoelectric conversion part that photoelectrically converts the light to generate electric charges, and a light generated by the first photoelectric conversion part. a first pixel that outputs a first signal based on charge;
a second light shielding part that shields part of the light transmitted through the optical system and the second microlens and has an area different from that of the first light shielding part; and a second photoelectric conversion part that photoelectrically converts light to generate electric charges. , a second pixel that outputs a second signal based on the charge generated by the second photoelectric conversion unit;
a third photoelectric conversion unit and a fourth photoelectric conversion unit photoelectrically converting light transmitted through the optical system and the third microlens to generate electric charges; and a third signal based on the electric charges generated by the third photoelectric conversion unit. and a third pixel that outputs a fourth signal based on the charge generated by the fourth photoelectric conversion unit;
with
the number of the first pixels and the number of the second pixels are less than the number of the third pixels;
image sensor. In the imaging device according to claim 1,
The imaging device, wherein the number of the first pixels is smaller than the number of the third pixels. In the imaging device according to claim 1 or 2 ,
An imaging device in which the number of the first pixels and the number of the second pixels are different. In the imaging device according to any one of claims 1 to 3 ,
The number of the first pixels in the first region of the imaging surface is smaller than the number of the second pixels in the second region of the imaging surface, which is farther from the optical axis of the optical system than the first region of the imaging surface. image sensor. In the imaging device according to claim 4 ,
The number of the first pixels in the first area of the imaging surface is the number of the first pixels in the second area of the imaging surface that is farther from the optical axis of the optical system than the first area of the imaging surface. and an imaging device having a number smaller than the number of the second pixels. In the imaging device according to claim 4 or 5 ,
a ratio of the number of the first pixels to the third pixels in the first region of the imaging surface is smaller than a ratio of the number of the first pixels to the third pixels in the second region of the imaging surface; element. In the imaging device according to any one of claims 4 to 6 ,
A ratio of the number of the first pixels and the number of the second pixels to the third pixels in the first region of the imaging surface is the ratio of the number of the first pixels to the third pixels in the second region of the imaging surface. an imaging element smaller than the ratio of the number and the number of the second pixels. In the imaging device according to any one of claims 1 to 7 ,
the first light shielding portion of the first pixel has an opening at a first position;
The imaging device, wherein the second light shielding portion of the first pixel has an opening at a second position different from the first position. In the imaging device according to any one of claims 1 to 8 ,
The first signal, the second signal, the third signal, and the fourth signal are image sensors used for focus detection of the optical system. In the imaging device according to any one of claims 1 to 9 ,
A signal obtained by adding the third signal and the fourth signal is an imaging element used for image generation. An imaging device according to any one of claims 1 to 10 ;
a generation unit that generates image data based on the signal output from the imaging device;
An imaging device comprising:

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