JP2021140179A - Image pick-up element, and imaging device - Google Patents

Abstract

To secure an amount of incidence upon each of a pair of photoelectric conversion units provided with respect to one microlens.SOLUTION: An image pick-up element is provided with: a plurality of first pixels that each include first and second photoelectric conversion parts photoelectrically converting light transmitting an optical system and a first microlens, and in which a difference between light reception areas of the first photoelectric conversion part and the second photoelectric conversion part varies at a first relationship according to a position of the light reception area in a first direction; and a plurality of second pixels that each include third and fourth photoelectric conversion parts photoelectrically converting light transmitting the optical system and a second microlens, and in which a difference between light reception areas of the third photoelectric conversion part and the fourth photoelectric conversion part varies at a second relationship different from the first relationship according to a position of the light reception area in the first direction.SELECTED DRAWING: Figure 3

Description

The present invention relates to an image pickup device and an image pickup device.

Conventionally, a pair of light receiving elements is provided for one microlens, and a focus detection pixel in which the pair of light receiving elements are arranged symmetrically with respect to the optical axis of the microlens and an optical axis of the microlens On the other hand, there is known an image sensor in which a pair of light receiving elements are arranged so as to be asymmetrical with focus detection pixels (for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2011-221253

However, since the amount of light incident on each of the pair of light receiving elements arranged for the same microlens is different, the output of one of the light receiving elements is saturated and cannot be used for the focus detection calculation, so that the focus is detected. There is a problem that accuracy cannot be maintained.

According to the first aspect, the image pickup element has a first photoelectric conversion unit and a second photoelectric conversion unit that photoelectrically convert the light transmitted through the optical system and the first microlens, respectively, and the first photoelectric conversion unit is provided. Light transmitted through the optical system and the second microlens, and a plurality of first pixels in which the difference in light receiving area between the unit and the second photoelectric conversion unit changes in the first relationship depending on the position in the first direction. Each has a third photoelectric conversion unit and a fourth photoelectric conversion unit for photoelectric conversion, and the difference in light receiving area between the third photoelectric conversion unit and the fourth photoelectric conversion unit depends on the position in the first direction. It includes a plurality of second pixels that change according to a second relationship different from the first relationship.

According to the present invention, it is possible to prevent the output of one of the pair of photoelectric conversion units from being saturated even in a pixel located near the periphery of the plurality of pixels, and to suppress a decrease in focus detection accuracy.

Cross-sectional view for explaining the configuration of the image pickup apparatus according to the embodiment of the present invention. A block diagram illustrating a configuration of a main part of an image pickup apparatus according to an embodiment. The figure which shows an example of the arrangement of the imaging pixel by embodiment The figure which shows typically the projection relationship between the area of the 1st photoelectric conversion part and the 2nd photoelectric conversion part of the image pickup pixel in embodiment, and the exit pupil region of a photographing lens system. The figure which shows an example of the arrangement of the imaging pixel in the modification The figure which shows an example of the arrangement of the imaging pixel in the modification The figure which shows an example of the arrangement of the imaging pixel in the modification

An image pickup device according to an embodiment of the present invention, and a focus detection device and an image pickup device provided with the image pickup device will be described with reference to the drawings. FIG. 1 is a cross-sectional view illustrating the configuration of a digital camera 100 which is an imaging device according to an embodiment. For convenience of explanation, a coordinate system consisting of an x-axis, a y-axis, and a z-axis is set as shown in the figure.

The digital camera 100 is a so-called mirrorless camera composed of a camera body 200 and a photographing lens body 300, and the photographing lens body 300 is mounted via a mount portion (not shown). A photographing lens body 300 having various photographing optical systems can be attached to the camera body 200 via a mount portion. The mount portion is provided with electrical contacts 201 and 202, and when the camera body 200 and the photographing lens body 300 are coupled, an electrical connection is established via the electrical contacts 201 and 202.

The photographing lens main body 300 includes a photographing lens system 1, an aperture 2, a drive mechanism 3, and a lens data unit 4. The photographing lens system 1 is an optical system for forming a subject image on a predetermined planned focal plane, and is composed of a plurality of lenses including a focus adjusting lens. The diaphragm 2 forms an aperture having a variable aperture diameter about the optical axis L in order to limit the light flux passing through the photographing lens system 1, that is, the amount of incident light. The drive mechanism 3 calculates the lens drive amount using the defocus amount input from the camera body 200 side via the electrical contact 201, and the optical axis of the focus adjustment lens constituting the photographing lens system 1 according to the lens drive amount. It is driven to the in-focus position along the L direction (z-axis direction). Further, the drive mechanism 3 outputs an aperture drive signal in response to a command from the camera body 200 side to control the drive of the aperture 2.

The lens data unit 4 is composed of, for example, a non-volatile recording medium, and stores various lens information related to the photographing lens body 300, such as the focal length and brightness (open F value) of the lens. The lens data unit 4 transmits the above lens information and the like to and from the camera body 200 via the electrical contact 202.

Inside the camera body 200, an arithmetic processing control unit 5, an image sensor control circuit 6, a mechanical shutter 7, an image sensor 8, an electronic viewfinder (EVF) 9, and an eyepiece 10 are provided. The camera body 200 is provided with an operation unit 11. Image pickup pixels such as CCD and CMOS are arranged two-dimensionally (rows and columns) on the xy plane in the image pickup element 8. The image pickup pixels of the image pickup device 8 are provided with R (red), G (green), and B (blue) color filters, respectively. The image sensor 8 receives a light beam incident through the photographing lens system 1 and the mechanical shutter 7 to image a subject image, and outputs an image pickup signal to the image sensor control unit 6. The imaging signal is used as a signal for generating image data (image signal) and as a signal for focusing detection (signal for focusing detection). Since the image sensor 8 captures the subject image through the color filter, the image pickup signal output from the image pickup pixel of the image pickup element 8 has color information of the RGB color system. The details of the image sensor 8 will be described later.

The mechanical shutter 7 is provided immediately before the image sensor 8, and is composed of a front curtain and a rear curtain composed of a plurality of light-shielding blades. The mechanical shutter 7 travels by driving a drive mechanism (not shown) composed of a drive motor (for example, an electric motor such as a DC motor or a stepping motor) to shield the image sensor 8 from the subject light. The electronic viewfinder 9 displays an image corresponding to the display image data generated by the arithmetic processing control unit 5. Further, the electronic viewfinder 9 displays various information (shutter speed, aperture value, ISO sensitivity, etc.) related to the shooting conditions. The image and various information displayed on the electronic viewfinder 9 are observed by the user through the eyepiece lens 10.

The operation unit 11 includes various switches provided corresponding to various operation members operated by the user, and outputs an operation signal corresponding to the operation of the operation member to the arithmetic processing control unit 5. The operating members include, for example, a release button, a menu button for displaying a menu screen on a rear monitor (not shown) provided on the back of the camera body 200, and a cross key operated when selecting and operating various settings. Includes a decision button for determining the settings selected by the cross key, an operation mode switching button for switching the operation of the digital camera 100 between the shooting mode and the playback mode, an exposure mode switching button for setting the exposure mode, and the like. ..

Further, the control system of the digital camera 100 will be described with reference to the block diagram shown in FIG. As shown in FIG. 2, the digital camera 100 includes an A / D conversion unit 12, an image processing circuit 13, a focus detection calculation circuit 14, and a body-lens communication unit 15. The arithmetic processing control unit 5 is an arithmetic circuit that has a CPU, ROM, RAM, and the like, and controls each component of the digital camera 100 and executes various data processing based on a control program. The control program is stored in a non-volatile memory (not shown) in the arithmetic processing control unit 5. The image sensor drive circuit 6 is controlled by the arithmetic processing control unit 5, controls the drive of the image sensor 8 and the A / D conversion unit 12, and causes the image sensor 8 to store charges, read out an image pickup signal, and the like. The A / D conversion unit 12 converts the analog image pickup signal output from the image pickup element 8 into digital.

The image processing circuit 13 uses the image pickup signal output from the image pickup element 8 as an image signal, performs various image processing on the image signal to generate image data, and then adds additional information or the like to create an image file. Generate. The image processing circuit 13 records the generated image file on a recording medium (not shown) such as a memory card. The image processing circuit 13 generates display image data for display on the electronic viewfinder 9 or a rear monitor (not shown) based on the generated image data or the image data recorded on the recording medium.

The focus detection calculation circuit 14 uses the image pickup signal output from the image pickup element 8 as a focus detection signal, and calculates the defocus amount using a known phase difference detection method. The body-lens communication unit 15 is controlled by the arithmetic processing control unit 5 and communicates with the drive mechanism 3 and the lens data unit 4 in the photographing lens main body 300 via the electrical contacts 201 and 202 to perform camera information (defocus amount). And aperture value, etc.) and receive lens information.

Next, the image pickup device 8 according to the present embodiment will be described in detail.
FIG. 3A is a plan view schematically showing a part of a region including the central portion of the image sensor 8, and FIG. 3B is a single imaging pixel 80 provided near the center of the image sensor 8. It is a figure which shows typically the cross section, and FIG. 3C is a figure which shows typically the cross section of one image pickup pixel 80 provided in the peripheral part of the image pickup element 8. Also in FIG. 3, the coordinate system including the x-axis, the y-axis, and the z-axis is set in the same manner as in the example shown in FIG. In the image pickup device 8, a plurality of image pickup pixels 80 are two-dimensionally arranged in the row direction (x direction) and the column direction (y direction). At each pixel position of the image pickup pixel 80, for example, the above-mentioned color filters (R: red filter, G: green filter, B: blue filter) are arranged according to the rules of the Bayer arrangement. In FIG. 3A, the colors of the color filters arranged on the imaging pixels 80 are schematically represented by notation as “R”, “G” or “B”.

The image pickup pixel 80 is composed of a microlens 81 and a first photoelectric conversion unit 82 and a second photoelectric conversion unit 83 provided under one microlens 81. The first photoelectric conversion unit 82 and the second photoelectric conversion unit 83 are arranged side by side in the x direction. In the example shown in FIG. 3, the first photoelectric conversion unit 82 is provided on the + side in the x direction, and the second photoelectric conversion unit 83 is provided on the − side in the x direction. Light incident on the first photoelectric conversion unit 82 and the second photoelectric conversion unit 83 are incident on the light incident through different regions of the photographing lens system 1, respectively. That is, a pair of subject luminous fluxes used by the focus detection calculation circuit 14 for the phase difference detection calculation are incident.

In the present embodiment, in each row, the boundary portion 84 between the first photoelectric conversion unit 82 and the second photoelectric conversion unit 83 deviates from the center of the microlens 81 according to the position where the imaging pixel 80 is arranged ( See FIG. 3 (c)). In all the imaging pixels 80, the total value of the area of the first photoelectric conversion unit 82 and the area of the second photoelectric conversion unit 83 is substantially the same. In other words, the size (area) of the first photoelectric conversion unit 82 and the size (area) of the second photoelectric conversion unit 83 are different. On the + side of the center row C of the image sensor 8 in the x direction + side, the boundary portion 84 shifts toward the x direction − side with respect to the center of the microlens 81, and on the x direction − side from the center row C, the center of the microlens 81. On the other hand, the boundary portion 84 shifts to the + side in the x direction. In other words, the area of the first photoelectric conversion unit 82 is larger than the area of the second photoelectric conversion unit 83, and the area of the first photoelectric conversion unit 82 and the area of the second photoelectric conversion unit 83 are increased according to the distance from the central row C. The difference from the area of is large. On the x-direction-side, the area of the second photoelectric conversion unit 83 is larger than the area of the first photoelectric conversion unit 82, and the area of the second photoelectric conversion unit 83 and the first one according to the distance from the central row C. The difference from the area of the photoelectric conversion unit 82 becomes large.

The amount of deviation of the boundary portion 84 with respect to the microlens 81, that is, the difference between the area of the second photoelectric conversion unit 83 and the area of the first photoelectric conversion unit 82 may change linearly according to the distance from the central row C. Alternatively, it may be changed stepwise for each predetermined number of imaging pixels 80. In each row, in the image pickup pixels 80 arranged in the center column C of the image pickup element 8, the center of the microlens 81 and the boundary portion 84 substantially coincide with each other, that is, the area of the first photoelectric conversion unit 82 and the second photoelectric conversion unit It is equal to the area of 83. As described above, since the total value of the area of the first photoelectric conversion unit 82 and the area of the second photoelectric conversion unit 83 is substantially the same in all the image pickup pixels 80, the image pickup pixel 80 is the image pickup element 8. The area ratio of the first photoelectric conversion unit 82 and the second photoelectric conversion unit 83 differs depending on the distance from the central row C in the x direction.

As shown in FIG. 3A, the boundary portion 84a between the first photoelectric conversion unit 82a and the second photoelectric conversion unit 83a provided in the image pickup pixels 80a arranged in the central row C of the image pickup element 8 is a microlens 81a. Is substantially equal to the center of. That is, the first photoelectric conversion unit 82a and the second photoelectric conversion unit 83a have the same area. In the image pickup pixels 80b arranged on the + side in the x direction with respect to the image pickup pixel 80a, the boundary portion 84b is displaced in the x direction − side with respect to the center of the microlens 81b. That is, the area of the first photoelectric conversion unit 82b is larger than the area of the second photoelectric conversion unit 83b. As described above, in all the imaging pixels 80, the total value of the area of the first photoelectric conversion unit 82 and the area of the second photoelectric conversion unit 83 is formed to be the same. Therefore, the area of the first photoelectric conversion unit 82b of the image pickup pixel 80b is larger than the area of the first photoelectric conversion unit 82a of the image pickup pixel 80a, and the area of the image pickup pixel 80b is larger than the area of the second photoelectric conversion unit 83a of the image pickup pixel 80a. The area of the second photoelectric conversion unit 83b is smaller.

In the image pickup pixels 80c arranged on the + side in the x direction with respect to the image pickup pixel 80b, the amount of deviation of the boundary portion 84c with respect to the center of the microlens 81c is larger than the amount of deviation of the boundary portion 84b with respect to the center of the microlens 81b. That is, as the imaging pixel 80 is arranged on the + side in the x direction, the amount of deviation between the boundary portion 84 and the center of the microlens 81 increases in the − side in the x direction. The area of the first photoelectric conversion unit 82c of the image pickup pixel 80c is larger than the area of the first photoelectric conversion unit 82b of the image pickup pixel 80b, and the area of the image pickup pixel 80c is larger than the area of the second photoelectric conversion unit 83b of the image pickup pixel 80b. 2 The area of the photoelectric conversion unit 83c is smaller.

In the image pickup pixels 80d arranged on the x-direction − side of the image pickup pixel 80a, the boundary portion 84d is shifted to the x-direction + side with respect to the center of the microlens 81d. That is, the area of the second photoelectric conversion unit 83d is larger than the area of the first photoelectric conversion unit 82d. Therefore, the area of the first photoelectric conversion unit 82d of the image pickup pixel 80d is smaller than the area of the first photoelectric conversion unit 82a of the image pickup pixel 80a, and the area of the image pickup pixel 80d is smaller than the area of the second photoelectric conversion unit 83a of the image pickup pixel 80a. The area of the second photoelectric conversion unit 83d is larger. In the image pickup pixels 80e arranged on the x-direction − side of the image pickup pixel 80d, the amount of deviation of the boundary portion 84e in the x direction + side with respect to the center of the microlens 81e is x with respect to the center of the microlens 81d of the boundary portion 84d. It is larger than the amount of deviation in the direction + side. That is, the area of the second photoelectric conversion unit 83e of the image pickup pixel 80e is larger than the area of the second photoelectric conversion unit 83d of the image pickup pixel 80d, and the area of the image pickup pixel 80e is larger than the area of the first photoelectric conversion unit 82d of the image pickup pixel 80d. The area of the first photoelectric conversion unit 82e is smaller.
The relationship between the boundary portion 84 and the center of the microlens 81 and the relationship between the area of the first photoelectric conversion unit 82 and the area of the second photoelectric conversion unit 83 will be described in detail later.

In each of the first photoelectric conversion unit 82 and the second photoelectric conversion unit 83 of the imaging pixel 80, the length in the y direction is not changed, but the length in the x direction is changed, so that the first photoelectric conversion unit 82 And the area ratio with the second photoelectric conversion unit 83 is changed. That is, in the image pickup pixels 80 arranged on the + side in the x direction, the length of the first photoelectric conversion unit 82 in the x direction increases as the distance from the center row C of the image pickup element 8 increases, and the second photoelectric conversion unit 82 increases. The length of 83 in the x direction is reduced. In the image pickup pixels 80 arranged on the x-direction-side, the length of the first photoelectric conversion unit 82 in the x-direction decreases as the distance from the center row C of the image pickup element 8 increases, and the length of the second photoelectric conversion unit 83 decreases. The length in the x direction increases.

In the image pickup pixels 80 arranged in the column direction (y direction) of the image pickup elements 8, the first photoelectric conversion unit 82 and the second photoelectric conversion unit 83 have the same area. That is, for example, for the imaging pixels 80 arranged in the same row as the imaging pixels 80c, the first photoelectric conversion unit 82 having the same area as the first photoelectric conversion unit 82c and the second photoelectric conversion unit 83c have the same area. A second photoelectric conversion unit 83 is provided.

In the present embodiment, the first photoelectric conversion unit 82 and the second photoelectric conversion unit 83 of the image pickup pixel 80 are shaped as described above to reduce the influence of eclipse in the peripheral region of the image pickup element 8. The principle will be described below.
FIG. 4 schematically shows the projection relationship between the areas of the first photoelectric conversion unit 82 and the second photoelectric conversion unit 83 of the imaging pixel 80 and the exit pupil region of the photographing lens system 1. FIG. 4A shows a case where the ejection pupil distance PO1 of the photographing lens system 1 and the ejection pupil distance PO2 of the imaging pixel 80 are substantially equal, that is, the photographing lens system 1 is compatible with the digital camera 100 which is a mirrorless camera. The case of a dedicated interchangeable lens designed in is shown. FIG. 4B shows a case where the ejection pupil distance PO1 of the photographing lens system 1 is longer than the ejection pupil distance PO2 of the imaging pixel 80, that is, the photographing lens system 1 is an interchangeable lens designed for, for example, a single-lens reflex camera. It is a dedicated interchangeable lens designed to be compatible with the digital camera 100 which is a mirrorless camera, but shows a case where a long ejection pupil distance PO1 is set. In FIG. 4B, for the purpose of facilitating understanding, the photographing lens system 1 when the exit pupil distances PO1 and PO2 are equal is shown by a broken line. Further, in the present embodiment, the exit pupil distance PO2 of the imaging pixel 80 is set to be shorter than the center value of the exit pupil distance PO1 that is different for each of the various dedicated interchangeable lenses. In the following description, the imaging pixels 80c arranged in the peripheral region on the + side in the x direction in FIG. 3 will be described as an example.

As shown in FIG. 4A, the first photoelectric conversion unit 82c has a luminous flux 851 that has passed through the exit pupil region 841 of the pair of exit pupil regions 841 and 842 of the photographing lens system 1 among the luminous flux from the subject. Is received through the microlens 81c, and the second photoelectric conversion unit 83c receives the luminous flux 852 that has passed through the exit pupil region 842 via the microlens 81c. As described above, FIG. 4A shows a case where the exit pupil distances PO1 and PO2 are substantially equal, so that the luminous fluxes 851 and 852 have no or little eclipse due to the structure of the photographing lens body 300 or the like. In this state, the light incident on the first photoelectric conversion unit 82c and the second photoelectric conversion unit 83c, respectively.

As shown in FIG. 4B, the luminous flux 852 from the subject passes through the exit pupil region 842 of the photographing lens system 1 and is incident on the second photoelectric conversion unit 83c via the microlens 81c of the imaging pixel 80c. Since the exit pupil distance PO1 of the photographing lens system 1 is longer than the exit pupil distance PO2 of the imaging pixel 80, a part of the luminous flux 851 from the subject is eclipsed. That is, of the luminous flux 851, the luminous flux 851a passes through the exit pupil region 841 of the photographing lens system 1 and is incident on the first photoelectric conversion unit 82c via the microlens 81c, and the luminous flux 851b is eclipsed and becomes the first photoelectric conversion unit 82c. No incident.

In the schematic plan view of the imaging pixel 80c of FIG. 4C, the luminous flux 852 and the luminous flux 851 affected by eclipse as described above, and the first photoelectric conversion unit 82c and the second photoelectric conversion unit 83c of the imaging pixel 80c Shows the positional relationship of. In FIG. 4C, a broken line indicates a region that would have been incident on the first photoelectric conversion unit 82c if the luminous flux 851b had not been eclipsed. In the present embodiment, the first photoelectric conversion unit 82c has a region 82c1 in which the luminous flux 851a is incident and a region 821c2 in which the luminous flux 851b would have been incident if it were not eclipsed. In the image pickup pixel 80c, the amount of deviation of the boundary portion 84c in the x-direction is such that the region 82c1 of the first photoelectric conversion unit 82c and the second photoelectric conversion unit 83c on which the luminous flux 852 is incident have the same area. It has been decided. Therefore, when the boundary portion 84c is displaced in the x-direction-side with respect to the center of the microlens 81c, the incident luminous fluxes 852 and 851a are substantially different in the first photoelectric conversion unit 82c and the second photoelectric conversion unit 83c, respectively. Light is received in the same area.

For the image pickup pixel 80b, similarly to the image pickup pixel 80c, the amount of deviation of the boundary portion 84b, that is, the area between the first photoelectric conversion unit 82b and the second photoelectric conversion unit 83b is determined. However, as described above, since the imaging pixels 80b are arranged on the x-direction − side of the imaging pixels 80c, the deviation amount of the boundary portion 84b is smaller than the deviation amount of the boundary portion 84c. That is, the area of the first photoelectric conversion unit 82b of the image pickup pixel 80b is smaller than the area of the first photoelectric conversion unit 82c of the image pickup pixel 80c. Further, with respect to the image pickup pixels 8 arranged on the x-direction-side from the center row C of the image pickup element 8, the boundary portion 84 is deviated from the center of the microlens 81, that is, the first photoelectric conversion unit 82 and the second photoelectric conversion unit 82. The magnitude relationship of the area of the conversion unit 83 is opposite.

FIG. 4D shows the exit pupil distance PO1 when it is assumed that the imaging pixels 80a are arranged at the positions where the imaging pixels 80c are arranged, that is, when the boundary portion 84 substantially coincides with the center of the microlens 81. It is a top view which shows typically the light beams 851 and 852 which are incident on the 1st photoelectric conversion part 82a and the 2nd photoelectric conversion part 83a, respectively, when it is larger than the exit pupil distance PO2. In this case, when the luminous flux 851 is eclipsed, the luminous flux 851a is received by the first photoelectric conversion unit 82a in the shaded area in the figure. The luminous flux 852 is received in the entire region of the second photoelectric conversion unit 83a. Therefore, the output of the image pickup signal from the first photoelectric conversion unit 82a is lower than the output of the image pickup signal from the second photoelectric conversion unit 83a. That is, the output of the imaging signal from the second photoelectric conversion unit 83c is saturated before the imaging signal from the first photoelectric conversion unit 82c reaches a sufficient output.

On the other hand, the present embodiment has the structure shown in FIG. 4 (c). Therefore, it is possible to prevent the output of the imaging signal from the first photoelectric conversion unit 82c from being lowered as compared with the output of the imaging signal from the second photoelectric conversion unit 83c, and the imaging signal from the first photoelectric conversion unit 82c is sufficient. It prevents the output of the imaging signal from the second photoelectric conversion unit 83c from being saturated before reaching the output.

The focus detection calculation circuit 14 uses the image pickup signal output from the image pickup pixel 80 having the above-mentioned structure as the focus detection signal, and calculates the defocus amount by using a known phase difference detection method. The focus detection calculation circuit 14 has a first signal sequence {an} in which the focus detection signals from the first photoelectric conversion unit 82 are sequentially arranged, and a second signal sequence in which the focus detection signals from the second photoelectric conversion unit 83 are sequentially arranged. The amount of deviation relative to {bn} is detected, and the focus adjustment state of the photographing lens system 1, that is, the defocus amount is detected.

The image processing circuit 13 uses the image pickup signal output from the image pickup pixel 80 as the image signal when generating the image data. The image processing circuit 13 adds the image pickup signal output from the first photoelectric conversion unit 82 and the image pickup signal output from the second photoelectric conversion unit 83 to treat each image pickup pixel 80 as an image signal. Therefore, there is no influence due to the area difference between the first photoelectric conversion unit 82 and the second photoelectric conversion unit 83. Since the image pickup pixel 80 is provided with a color filter of any of R color, G color, and B color, the added image signal has color information corresponding to the color filter provided in the image pickup pixel 80. The image processing circuit 13 performs various image processing on the image signal generated by the addition to generate image data, and adds additional information or the like to generate an image file.

According to the above-described embodiment, the following effects can be obtained. In all the plurality of imaging pixels 80, the total area of the pair of first photoelectric conversion units 82 and the second photoelectric conversion unit 83 is substantially equal, and the arrangement positions of the plurality of imaging pixels 80, that is, the center of the imaging element 8 The areas of the pair of first photoelectric conversion units 82 and the second photoelectric conversion units 83 differ depending on the distance from the vicinity. That is, as the distance from the vicinity of the center of the image sensor 8 increases, the area difference between the pair of first photoelectric conversion units 82 and the second photoelectric conversion unit 83 increases. Therefore, when the incident light beam is affected by eclipse in the peripheral portion of the image sensor 8, such as when the photographing lens system 1 in which the exit pupil distance PO1 is longer than the exit pupil distance PO2 of the image sensor 8 is attached. Even so, the amount of light incident on the first photoelectric conversion unit 82 or the second photoelectric conversion unit 83 can be secured. Therefore, the second photoelectric conversion unit 83 receives the light flux 852 that is not affected by the eclipse by the time the first photoelectric conversion unit 82 receives the light amount that can be calculated for the luminous flux 851 that is affected by the eclipse. 2 It is possible to prevent the output of the photoelectric conversion unit 83 from being saturated and suppress a decrease in focus detection accuracy.

The following modifications are also within the scope of the present invention, and one or more of the modifications can be combined with the above-described embodiment.
(1) In the embodiment, as shown in FIG. 4, the case where the exit pupil distance PO1 of the photographing lens system 1 is longer than the exit pupil distance PO2 of the imaging pixel 80 has been described, but the exit pupil distance PO1 is short. The case where the system 1 is attached will be described. In this case, eclipse does not occur in the luminous flux 851, but eclipse occurs in the luminous flux 852. Therefore, the luminous flux 851 from the subject passes through the exit pupil region 841 of the photographing lens system 1 and is incident on the first photoelectric conversion unit 82c via the microlens 81c of the imaging pixel 80c. Further, when the luminous flux 852 is eclipsed, a part of the luminous flux 852 passes through the exit pupil region 842 of the photographing lens system 1 and is incident on the second photoelectric conversion unit 83c via the microlens 81c. In this case, in order to reduce the influence of eclipse in the peripheral region of the image sensor 8, the area of the first photoelectric conversion unit 82c of the image sensor 80c should be made larger than the area of the second photoelectric conversion unit 83c. Just do it. That is, the imaging pixels 80e may be arranged in place of the imaging pixels 80c shown in FIG. 3A.

FIG. 5 shows an example of the arrangement of the image pickup pixels 80 in the image pickup element 8 when the exit pupil distance PO1 corresponds to the photographing lens system 1 shorter than the exit pupil distance PO2. As shown in FIG. 5, the area of the first photoelectric conversion unit 82 is smaller than the area of the second photoelectric conversion unit 83 on the + side in the x direction from the center row C of the image pickup element 8, and is from the center row C. The difference between the area of the first photoelectric conversion unit 82 and the area of the second photoelectric conversion unit 83 increases according to the distance. On the x-direction-side, the area of the second photoelectric conversion unit 83 is smaller than the area of the first photoelectric conversion unit 82, and the area of the second photoelectric conversion unit 83 and the first one according to the distance from the central row C. The difference from the area of the photoelectric conversion unit 82 becomes large. Also in this case, in the image pickup pixels 80 arranged in the central column C of the image pickup element 8 in each row, the area of the first photoelectric conversion unit 82 and the area of the second photoelectric conversion unit 83 are equal to each other.

(2) In FIG. 6, either the photographing lens system 1 in which the exit pupil distance PO1 is longer than the exit pupil distance PO2 or the photographing lens system 1 in which the exit pupil distance PO1 is shorter than the exit pupil distance PO2 An example of the arrangement of the image pickup pixels 80 of the image pickup element 8 is shown. In this case, a row in which the imaging pixels 80 having the structure shown in FIG. 3A are arranged (rows D2, D4, D6 in FIG. 6) and a row in which the imaging pixels 80 having the structure shown in FIG. 5 are arranged (rows D2, D4, D6 in FIG. Rows D1, D3, D5) of FIG. 6 are alternately arranged along the y direction. Therefore, in the case of the photographing lens system 1 in which the ejection pupil distance PO1 is longer than the ejection pupil distance PO2, the imaging signals output from the imaging pixels 80 arranged in rows D2, D4, and D6 are used, and the ejection pupil distance PO1 is used. In the case of the photographing lens system 1 in which is shorter than the ejection pupil distance PO2, the focus detection that reduces the influence of eclipse is reduced by using the imaging signals output from the imaging pixels 80 arranged in rows D1, D3, and D5. Can be done.

(3) Instead of the first photoelectric conversion unit 82 and the second photoelectric conversion unit 83 of the imaging pixel 80 arranged side by side in the x direction, the first photoelectric conversion unit 82 and the second photoelectric conversion unit are arranged. Those arranged side by side in the y direction are also included in one aspect of the present invention. Further, in the image pickup element 8, the image pickup pixel 80 in which the first photoelectric conversion unit 82 and the second photoelectric conversion unit 83 are arranged side by side in the x direction, and the first photoelectric conversion unit 82 and the second photoelectric conversion unit 83 are arranged. One aspect of the present invention also includes an array of imaging pixels 80 arranged side by side in the y direction.

(4) As shown in FIG. 7, the present invention also relates to an image sensor 8 in which the first photoelectric conversion unit 82 is arranged on one of the pair of image pickup pixels 80 and the second photoelectric conversion unit 83 is arranged on the other image pickup pixel 80. It is included in one aspect of the invention. In this case, in the pair of image pickup pixels 80a1 and 80a2 arranged in the central row C of the image pickup element 8, the second photoelectric conversion unit 83a included in the image pickup pixel 80a1 and the first photoelectric conversion unit 82a included in the image pickup pixel 80a2 are , The areas are substantially equal. In the pair of image pickup pixels 80c1 and 80c2 arranged in the peripheral portion (x direction + side in FIG. 7), the area of the second photoelectric conversion unit 83c possessed by the image pickup pixel 80c1 is possessed by the image pickup pixel 80c2. It is larger than the area of the first photoelectric conversion unit 82c. The difference in area is determined according to the distance from the center row C of the image sensor 8 as in the case of the embodiment. Therefore, even when the image sensor 8 is composed of the image pickup pixels 80 having the configuration shown in FIG. 7, it is possible to reduce the influence of the eclipse of the luminous flux in the peripheral portion of the image pickup element 8 and maintain the incident light amount. Therefore, it is possible to suppress a decrease in focus detection accuracy.

The present invention is not limited to the above-described embodiment as long as the features of the present invention are not impaired, and other embodiments considered within the scope of the technical idea of the present invention are also included within the scope of the present invention. ..

8 ... image sensor, 13 ... image processing circuit, 14 ... focus detection calculation circuit, 80 ... image pixel, 81 ... microlens, 82 ... first photoelectric conversion unit, 83 ... second photoelectric conversion unit, 100 ... digital camera

Claims (10)

It has a first photoelectric conversion unit and a second photoelectric conversion unit that photoelectrically convert the light transmitted through the optical system and the first microlens, respectively, and has a light receiving area between the first photoelectric conversion unit and the second photoelectric conversion unit. With a plurality of first pixels whose difference is changed in the first relationship depending on the position in the first direction,
It has a third photoelectric conversion unit and a fourth photoelectric conversion unit that photoelectrically convert the light transmitted through the optical system and the second microlens, and receives light from the third photoelectric conversion unit and the fourth photoelectric conversion unit. A plurality of second pixels in which the difference in area changes in a second relationship different from the first relationship depending on the position in the first direction.
An image sensor comprising. In the image pickup device according to claim 1,
The light receiving area of the first photoelectric conversion unit is larger than the light receiving area of the second photoelectric conversion unit.
The light receiving area of the third photoelectric conversion unit is smaller than the light receiving area of the fourth photoelectric conversion unit. In the image pickup device according to claim 1 or 2.
The light receiving area of the first photoelectric conversion unit becomes larger than the light receiving area of the second photoelectric conversion unit as the distance from the optical axis of the optical system increases.
An image sensor in which the light receiving area of the third photoelectric conversion unit is smaller than the light receiving area of the fourth photoelectric conversion unit as the distance from the optical axis of the optical system increases. The image sensor according to any one of claims 1 to 3.
An image pickup device in which the light receiving area between the first photoelectric conversion unit and the second photoelectric conversion unit changes linearly with respect to the distance from the optical axis of the optical system. The image sensor according to any one of claims 1 to 4.
An image pickup device in which the light receiving area between the first photoelectric conversion unit and the second photoelectric conversion unit changes for each of a plurality of the first pixels from the optical axis of the optical system. The image sensor according to any one of claims 1 to 5.
An image sensor in which the difference in light receiving area between the first photoelectric conversion unit and the second photoelectric conversion unit increases as the distance from the optical axis of the optical system increases. The image sensor according to any one of claims 1 to 6.
An image sensor in which the difference in light receiving area between the first photoelectric conversion unit and the second photoelectric conversion unit changes linearly with respect to the distance from the optical axis of the optical system. In the image pickup device according to any one of claims 1 to 7.
An image pickup device in which the difference in light receiving area between the first photoelectric conversion unit and the second photoelectric conversion unit changes for each of a plurality of the first pixels from the optical axis of the optical system. The image sensor according to any one of claims 1 to 8 and the image sensor.
A detection unit that detects the focus of the optical system based on at least one of the signal output by the first pixel and the signal output by the second pixel.
An imaging device comprising. In the imaging device according to claim 9,
The detection unit selects at least one of the signal output by the first pixel and the signal output by the second pixel based on the information of the exit pupil distance of the optical system, and detects the focus of the optical system. Imaging device to perform.

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