Image sensor and imaging device

Abstract

The present invention provides an image sensor that can detect focus with high accuracy at any image height, even when used in combination with a photographic lens that exhibits a large change in exit pupil distance depending on the image height. [Solution] The image sensor is an image sensor in which pixels having a plurality of photoelectric conversion regions divided in a first direction are arranged in a two-dimensional manner, wherein the direction of the long side of the image sensor coincides with the first direction, and in the first direction, the amount of change in the image height, which is the distance from the center of the image sensor, of the amount of deviation between the optical axis of the microlens of the pixel and the center of the divided region of the photoelectric conversion region is a first amount of change when the image height is on the center side of a first predetermined image height, and a second amount of change when the image height is outside the first predetermined image height, and the first amount of change is greater than the second amount of change.

Description

Technical Field

[0001] The present invention relates to an imaging device and an imaging apparatus.

Background Art

[0002] One of the focus detection methods performed in an imaging apparatus is an imaging surface phase difference method in which phase difference focus detection is performed by focus detection pixels formed on an imaging device. Patent Document 1 discloses a technique for changing the optical axis of a microlens in accordance with an image height because the exit pupil distance of a photographing lens changes in the positive direction (the side where the photographing lens is arranged) and the negative direction (the side where the photographing lens is not arranged) depending on the image height.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, according to the conventional technology, it is not assumed for the case of using a combination of a photographing lens and an imaging device in which the change in the exit pupil distance is large according to the image height, and there is a possibility that the accuracy of focus detection may decrease at an arbitrary image height. An object of the present invention is to provide an imaging device that can perform high-precision focus detection at an arbitrary image height even when used in combination with a photographing lens in which the change in the exit pupil distance is large according to the image height.

Means for Solving the Problems

[0005] To solve the above problems, the present invention provides an image sensor in which pixels having a plurality of photoelectric conversion regions divided in a first direction are arranged in a two-dimensional manner, wherein the direction of the long side of the image sensor coincides with the first direction, and in the first direction, the amount of change in the image height (distance from the center of the image sensor) of the difference between the optical axis of the microlens of the pixel and the center of the divided region of the photoelectric conversion region is a first amount of change when the image height is on the center side of a first predetermined image height, and a second amount of change when the image height is on the outside side of the first predetermined image height, and the first amount of change is greater than the second amount of change. [Effects of the Invention]

[0006] According to the present invention, it is possible to provide an image sensor that can detect focus with high accuracy at any image height, even when used in combination with a photographic lens that exhibits a large change in exit pupil distance depending on the image height. [Brief explanation of the drawing]

[0007] [Figure 1] This shows the general configuration of the camera. [Figure 2] This diagram shows the arrangement of pixels in an image sensor. [Figure 3] (A) is a plan view of the pixel as seen from the light-receiving surface side of the image sensor, and (B) is a cross-sectional view of the pixel shown in (A) as seen from the -y side. [Figure 4] Figure 3(A) shows a cross-sectional view of the pixel shown from the +y side and the exit pupil surface of the imaging optical system. [Figure 5] This is a schematic diagram showing the relationship between the pixels of the image sensor and the first and second pupil regions. [Figure 6] (A) and (B) are diagrams showing the light intensity distribution when light is incident on a microlens formed in a pixel. [Figure 7] This figure shows the light-receiving rate distribution (pupil intensity distribution) depending on the angle of incidence of light. [Figure 8] This diagram shows the relationship between the entrance pupil of the image sensor and the exit pupil of the imaging optical system. [Figure 9] This figure shows the relationship between image height and exit pupil angle for a specific lens. [Figure 10] This figure shows the relationship between image height and displacement when the incident pupil distance and exit pupil distance are equal, in the case where a photographic lens having the relationship between image height and exit pupil angle shown in Figure 9 is used. [Figure 11] This figure shows the relationship between the image height of the image sensor and the change in the amount of displacement for any given image height. [Figure 12] Figures (A) through (C) show the relationship between the change in the amount of displacement with respect to the image height for each pixel in the image sensor. [Figure 13] (A) is a plan view of a modified pixel as seen from the light-receiving surface side of the image sensor, and (B) is a cross-sectional view of the pixel shown in (A) as seen from the -y side. [Figure 14] This diagram shows the relationship between the entrance pupil of the image sensor and the exit pupil of the imaging optical system. [Figure 15] This figure shows the relationship between the image height of the image sensor and the change in the amount of displacement for any given image height. [Figure 16] Figures (A) through (C) show the relationship between the change in the amount of displacement with respect to the image height for each pixel in the image sensor. [Modes for carrying out the invention]

[0008] Embodiments of the present invention will be described below with reference to the drawings. Figure 1 shows a schematic configuration of camera 1. Camera 1, as an example of an imaging device, comprises a first lens group 101, an aperture / shutter 102, a second lens group 103, a third lens group 105, an optical filter 106, and an image sensor 107. Camera 1 also comprises a zoom actuator 111, an aperture shutter actuator 112, a focus actuator 114, an illumination device 115, an auxiliary light-emitting unit 116, a control unit 121, an illumination control circuit 122, an auxiliary drive circuit 123, and an imaging drive circuit 124. Furthermore, camera 1 comprises an image processing circuit 125, a focus drive circuit 126, an aperture shutter drive circuit 128, a zoom drive circuit 129, a display 131, an operation unit 132, and a storage medium 133.

[0009] The first lens group 101 is positioned at the front of the imaging optical system and is held so as to be able to move back and forth in the optical axis direction. The aperture-integrated shutter 102 adjusts the amount of light during shooting by adjusting the aperture diameter. The aperture-integrated shutter 102 also functions as a shutter for adjusting the exposure time when shooting still images. The second lens group 103 moves back and forth in the optical axis direction in conjunction with the aperture-integrated shutter 102, and in conjunction with the movement of the first lens group 101, it realizes a zoom function. The third lens group 105 (focus lens) adjusts the focus by moving back and forth in the optical axis direction. The optical filter 106 is an optical element for reducing false colors and moiré in captured images. The image sensor 107 consists of a two-dimensional CMOS photosensor and its peripheral circuitry, and is positioned on the imaging plane of the imaging optical system. Note that the first lens group 101, the second lens group 103, and the third lens group 105 are examples of imaging optical systems. Furthermore, the first lens group 101, the second lens group 103, and the third lens group 105 can also be considered as photographic lenses. The zoom actuator 111 rotates a cam cylinder (not shown) to drive the first lens group 101 and the second lens group 103 forward and backward in the optical axis direction, thereby performing a magnification operation. The aperture shutter actuator 112 controls the aperture diameter of the aperture / shutter 102 to adjust the amount of light used for shooting, and also controls the exposure time when shooting still images. The focus actuator 114 drives the third lens group 105 forward and backward in the optical axis direction to adjust the focus. The illumination device 115 is used as illumination during shooting. A flash illumination device using a xenon tube is preferably used as the illumination device 115, but an illumination device equipped with a continuously emitting LED may also be used. The auxiliary light-emitting unit 116 projects an image of a mask having a predetermined aperture pattern onto the field of view via a light-emitting lens, improving the focus detection capability for dark or low-contrast subjects.

[0010] The control unit 121 controls the entire camera 1. The control unit 121 includes a calculation unit, ROM, RAM, A / D converter, D / A converter, communication interface circuit, etc. Based on a predetermined program stored in the ROM, the control unit 121 drives various circuits of the camera 1 and performs a series of operations such as AF, shooting, image processing, and recording. The illumination control circuit 122 controls the lighting of the illumination device 115 in synchronization with the shooting operation. The auxiliary drive circuit 123 controls the lighting of the auxiliary light-emitting unit 116 in synchronization with the focus detection operation. The imaging drive circuit 124, as an example of a processing means, controls the imaging operation of the image sensor 107 and performs A / D conversion of the acquired image signal and transmits it to the control unit 121. The image processing circuit 125, as an example of a processing means, performs processing such as gamma conversion, color interpolation, and JPEG compression of the image acquired by the image sensor 107. The focus drive circuit 126 drives the focus actuator 114 based on the focus detection result and drives the third lens group 105 forward and backward in the optical axis direction to adjust the focus. The aperture shutter drive circuit 128 controls the aperture shutter actuator 112 to control the opening of the aperture / shutter 102. The zoom drive circuit 129 drives the zoom actuator 111 in response to the user's zoom operation. The display 131 displays information regarding the shooting mode of the camera, preview images before shooting and confirmation images after shooting, an in-focus state display image at the time of focus detection, etc. Examples of the display 131 include an LCD. The operation unit 132 receives operations of the camera 1 by the user. The operation unit 132 includes a power switch, a release (shooting trigger) switch, a zoom operation switch, a shooting mode selection switch, etc. The storage medium 133 records captured images. The storage medium 133 may be detachable from the camera 1.

[0011] FIG. 2 is a diagram showing the arrangement of pixels 200 in the image sensor 107. In FIG. 2, the horizontal direction in the figure may be referred to as the x direction, the vertical direction in the figure may be referred to as the y direction, and the front-rear direction in the figure may be referred to as the z direction. As shown in FIG. 2, pixel groups 200P are provided in the image sensor 107. Each pixel group 200P has four pixels 200 provided therein. One of these four pixels 200 includes a pixel 200R having red spectral sensitivity, two pixels 200G having green spectral sensitivity are included, and one pixel 200B having blue spectral sensitivity is included. More specifically, in the pixel group 200P, the pixel 200R having red spectral sensitivity is provided at the upper left, the pixels 200G having green spectral sensitivity are provided at the upper right and the lower left, and the pixel 200B having blue spectral sensitivity is provided at the lower right. Also, in each pixel 200, a first focus detection pixel 201 and a second focus detection pixel 202 are provided side by side in the x direction. When the first focus detection pixel 201 and the second focus detection pixel 202 are described without particularly distinguishing them, they may simply be referred to as focus detection pixels. <000009​In the illustrated example, the pixel group 200P is arranged in 2 rows × 2 columns. Also, in the illustrated example, the pixels 200 are arranged in 4 rows × 4 columns. Further, in the illustrated example, the focus detection pixels are arranged in 4 rows × 8 columns. In the present embodiment, by arranging a large number of the 2-row × 2-column pixel groups 200P shown in FIG. 2 on the plane, an imaging image (focus detection signal) is acquired. Also, the imaging device 107 of the present embodiment has a horizontal size H of 36 mm, a vertical size V of 24 mm, a pixel period P of 4.8 μm, and a pixel number N of 7500 columns horizontally × 5000 rows vertically = 37.5 million pixels. Also, the imaging device 107 has a column direction period PAF of the focus detection pixels of 2.4 μm and a focus detection pixel number NAF of 15000 columns horizontally × 5000 rows vertically = 75 million pixels.

[0013] FIG. 3(A) is a plan view of the pixel 200 as viewed from the light receiving surface side (+z side) of the imaging device 107, and FIG. 3(B) is a cross-sectional view taken along line a-a of the pixel 200 shown in FIG. 3(A) as viewed from the -y side. As shown in FIG. 3, a microlens 305 for condensing incident light is formed on the light receiving side of each pixel in the pixel 200. Also, in the pixel 200, a photoelectric conversion unit 301 and a photoelectric conversion unit 302 that are NH-divided (2-divided) in the x direction and NV-divided (1-divided) in the y direction are formed. The photoelectric conversion unit 301 corresponds to the first focus detection pixel 201, and the photoelectric conversion unit 302 corresponds to the second focus detection pixel 202. The photoelectric conversion unit 301 and the photoelectric conversion unit 302 may be pin-structure photodiodes having an intrinsic layer sandwiched between a p-type layer and an n-type layer. Also, the photoelectric conversion unit 301 and the photoelectric conversion unit 302 may be pn junction photodiodes in which the intrinsic layer is omitted. Also, a microlens 305 and a color filter 306 are formed in the pixel 200. Note that the spectral transmittance of the color filter 306 may change according to the focus detection pixel, or the color filter 306 may be omitted. When the photoelectric conversion unit 301 and the photoelectric conversion unit 302 are described without particularly distinguishing them, they may simply be referred to as the photoelectric conversion unit.

[0014] Light incident on pixel 200 is focused by microlens 305, spectrally separated by color filter 306, and then received by photoelectric conversion unit 301 and photoelectric conversion unit 302. In photoelectric conversion unit 301 and photoelectric conversion unit 302, electron-hole pairs are generated according to the amount of light received. After separation in the depletion layer, negatively charged electrons are accumulated in the n-type layer (not shown), while holes are discharged to the outside of the image sensor 107 through the p-type layer connected to a constant voltage source (not shown). Electrons accumulated in the n-type layer (not shown) of photoelectric conversion unit 301 and photoelectric conversion unit 302 are transferred to the capacitance unit (FD) via a transfer gate, converted into a voltage signal, and output. The focal position of microlens 305 changes depending on the shape (curvature, etc.), material (refractive index, etc.) of the microlens, and its positional relationship with the corresponding photoelectric conversion unit. The focal position of microlens 305 can be set by setting these parameters.

[0015] Figure 4 shows a cross-sectional view of pixel 200 shown in Figure 3(A) as seen from the +y side, and the exit pupil surface of the imaging optical system. The pupil region 500 shown in Figure 4 is the pupil region that can receive light across the entire pixel 200 when the photoelectric conversion unit 301 and the photoelectric conversion unit 302 (first focus detection pixel 201 and second focus detection pixel 202) are combined. The pupil region 500 has a first pupil portion region 501 and a second pupil portion region 502. The first pupil portion region 501 is roughly conjugate to the light-receiving surface of the photoelectric conversion unit 301, whose center of gravity is eccentric in the -x direction, and the microlens 305, and represents the pupil region that can receive light with the first focus detection pixel 201. The center of gravity of the first pupil portion region 501 is eccentric on the pupil surface towards the +X side and overlaps with the center of the aperture 400 of the aperture / shutter 102 towards the +X side. Furthermore, the second pupil region 502 is roughly conjugate to the light-receiving surface of the photoelectric conversion unit 302, whose center of gravity is eccentric in the +x direction, by the microlens 305, and represents the pupil region that can be detected by the second focus detection pixel 202. The center of gravity of the second pupil region 502 is eccentric to the -x side on the pupil surface and overlaps the center of the aperture 400 to the -x side.

[0016] Figure 5 is a schematic diagram showing the relationship between the pixels 200 of the image sensor 107 and the first pupil region 501 and the second pupil region 502. At the entrance pupil distance Zs of the image sensor 107, the first pupil region 501 corresponding to the light-receiving area of ​​the first focus detection pixel 201 roughly coincides for each pixel 200 on the surface 600 of the image sensor 107. Also, at the entrance pupil distance Zs of the image sensor 107, the second pupil region 502 corresponding to the light-receiving area of ​​the second focus detection pixel 202 roughly coincides for each pixel 200 on the surface 600 of the image sensor 107. In other words, at the entrance pupil distance Zs of the image sensor 107, the pupil division positions of the first pupil region 501 and the second pupil region 502 roughly coincide for each pixel 200. A pair of light beams passing through the first pupil region 501 and the second pupil region 502 are incident on each pixel 200 of the image sensor 107 at different angles and are received by the first focus detection pixel 201 and the second focus detection pixel 202 of each pixel 200.

[0017] Figure 6 shows the light intensity distribution when light is incident on a microlens 305 formed on a pixel 200. More specifically, Figure 6(a) shows the light intensity distribution in a cross-section parallel to the optical axis of the microlens 305, and Figure 6(b) shows the light intensity distribution in a cross-section perpendicular to the optical axis of the microlens 305 at the focal position of the microlens 305. The incident light is focused to the focal position by the microlens 305. However, due to the effect of diffraction due to the wave nature of light, the diameter of the focused spot cannot be made smaller than the diffraction limit Δ and is of a finite size. The size of the light-receiving surface of the photoelectric conversion unit is about 1 to 2 μm, while the focused spot of the microlens 305 is about 1 μm. Therefore, the first pupil region 501 and the second pupil region 502 shown in Figure 4, which are conjugate to the light-receiving surface of the photoelectric conversion unit via the microlens 305, are not clearly divided into pupils due to diffraction blur, resulting in a light-receiving rate distribution (pupil intensity distribution) that depends on the angle of incidence of light.

[0018] Figure 7 shows the light reception rate distribution (pupil intensity distribution) dependent on the angle of incidence of light. In Figure 7, the horizontal axis represents the angle of incidence of light θ (which can be converted to pupil coordinates), and the vertical axis represents the light reception rate. Figure 7 shows the pupil intensity distribution PI1(θ) along the x-direction of the first pupil region 501 and the pupil intensity distribution PI2(θ) along the x-direction of the second pupil region 502 in Figure 4. Furthermore, Figure 7 shows the pupil intensity distribution PI(θ) = PI1(θ) + PI2(θ) along the x-direction of the pupil region 500, which is the combined pupil region 501 and the second pupil region 502 in Figure 4. As shown in the figure, it can be seen that the pupil is gradually divided. It can also be seen that the light-receiving rate of the image sensor 107 decreases as the angle of incidence increases. When the angle of incidence of the photographic lens used in combination with the image sensor 107 increases, an angle is used that reduces the light-receiving rate of the image sensor 107. When a white paper with uniform brightness is photographed with camera 1, there is a phenomenon in which light falls off at the peripheral image height of the captured image data during development. This phenomenon in which the amount of light falls off at the peripheral image height of the image sensor 107 during photography is called shading. Shading is a phenomenon that occurs when the exit pupil of the photographic lens views an area where the light-receiving rate of the image sensor 107 has decreased.

[0019] Although the pupil region 500 in this embodiment has been described as being divided into two parts horizontally, it is not limited to this. The pupil region 500 may also be divided vertically. Furthermore, in the example described above, the image sensor 107 has multiple pixels 200, each consisting of a first focus detection pixel 201 and a second focus detection pixel 202, arranged in a single array, but is not limited to this. For example, the image sensor 107 may have pixels 200, a first focus detection pixel 201, and a second focus detection pixel 202 separately, and the first focus detection pixel 201 and the second focus detection pixel 202 may be partially arranged in a part of the array of pixels 200. In this embodiment, focus detection is performed by collecting the light received signals from the first focus detection pixels 201 in each pixel 200 of the image sensor 107 to generate a focus detection signal, and also by collecting the light received signals from the second focus detection pixels 202 in each pixel 200 of the image sensor 107 to generate a focus detection signal. Furthermore, the image sensor 107 generates an imaging signal (imaging image) with a resolution of effective pixels N by adding the signals from the first focus detection pixels 201 and the second focus detection pixels 202 for each pixel 200.

[0020] Figure 8 shows the relationship between the entrance pupil of the image sensor 107 and the exit pupil of the imaging optical system. Figure 8 shows pixels 200 arranged in the x-direction on the surface 600 of the image sensor 107. More specifically, Figure 8 shows a central pixel 200C located at the center in the x-direction of the image sensor 107, pixels 200 located to the right of the central pixel 200C in the x-direction, and pixels 200 located to the left of the central pixel 200C in the x-direction. In the following explanation, the pixels 200 located to the right of the central pixel 200C in the x-direction will be the subject of the explanation, and these pixels 200 will be referred to as the target pixels 200. Also, the x-direction shown in Figure 8 is the direction in which the pupil region 500 is divided into a first pupil region 501 and a second pupil region 502. Therefore, the x-direction will be referred to as the pupil division direction in the following explanation.

[0021] Figure 8 also shows the optical axis C of the microlens 305 at the central pixel 200C. Furthermore, Figure 8 shows the exit pupil distance L0 and the incident angle θ0 to the target pixel 200 at the exit pupil distance L0, when the incident pupil distance Zs and exit pupil distance of the image sensor 107 are the same at an arbitrary image height R1 in the pupil division direction of the image sensor 107. The incident angle θ0 is the angle at which the light reception intensity of the photoelectric conversion unit 301 and the light reception intensity of the photoelectric conversion unit 302 are equal at the target pixel 200. The angle at which the light reception intensity of the photoelectric conversion unit 301 and the light reception intensity of the photoelectric conversion unit 302 are equal at the pixel 200 may hereafter be referred to as the sensor pupil angle. The sensor pupil angle of the central pixel 200C is 0°. Figure 8 also shows the exit pupil distance L1 and the angle of incidence θ1 to the target pixel 200 at exit pupil distance L1 when the exit pupil distance is shorter than the entry pupil distance Zs at image height R1. Figure 8 also shows the exit pupil distance L2 and the angle of incidence θ2 to the target pixel 200 at exit pupil distance L2 when the exit pupil distance is longer than the entry pupil distance Zs at image height R1. The angle corresponding to the exit pupil distance may be referred to as the exit pupil angle below. The exit pupil angle corresponding to exit pupil distance L0 at the target pixel 200 is angle θ0. The exit pupil angle corresponding to exit pupil distance L1 at the target pixel 200 is angle θ1. The exit pupil angle corresponding to exit pupil distance L2 at the target pixel 200 is angle θ2.

[0022] Figure 8 also shows the interval 601 between the peak position of the pupil intensity distribution in the first pupil region 501 and the peak position of the pupil intensity distribution in the second pupil region 502. Furthermore, Figure 8 shows the angular range 602 of the interval 601 as viewed from image height R1, and the central axis 603 of the divided photoelectric conversion region in the target pixel 200. The central axis 603 is the central axis in the pupil division direction between the photoelectric conversion unit 301 and the photoelectric conversion unit 302 of the target pixel 200. The central axis 603 can also be considered as the central axis of pupil division in the pupil separation direction at image height R1. Finally, Figure 8 shows the optical axis 604 of the microlens 305 in the target pixel 200, and the amount of displacement R2 between the central axis 603 and the optical axis 604.

[0023] In this embodiment, without considering the effects of manufacturing variations such as misalignment of the microlens 305, the optical axis 604 is assumed to be in an ideal state where it is shifted toward the central image height side of the image sensor 107 relative to the central axis 603 in the target pixel 200. Furthermore, the exit pupil distance of the imaging optical system changes according to the image height of the image sensor 107.

[0024] The entrance pupil distance Zs is determined by the positional relationship between the central axis 603 and the optical axis 604, in other words, the relationship between the image height R1 and the displacement amount R2. More specifically, the larger the displacement amount R2 is relative to the image height R1, the shorter the entrance pupil distance Zs becomes. The smaller the displacement amount R2 is relative to the image height R1, the longer the entrance pupil distance Zs becomes. Also, when the displacement amount R2 is "0", the principal ray angle of the pixel 200 at any image height position is 0° and is parallel to the principal ray angle of the central pixel 200C, so the entrance pupil distance Zs becomes infinite. In this embodiment, for pixels 200 located away from the center in the x direction on the image sensor 107, such as the target pixel 200, the displacement amount R2 is greater than 0, and the optical axis 604 is located closer to the center of the image sensor 107 than the central axis 603. Also, in the example shown in Figure 8, the central axis 603 is assumed to pass through the center of the pixel 200 in the x direction.

[0025] At the entrance pupil distance Zs, for every 200 pixels of the image sensor 107, the first pupil region 501, which is the light-receiving area (entrance pupil) of the first focus detection pixel 201, and the second pupil region 502, which is the light-receiving area of ​​the second focus detection pixel 202, intersect approximately along the optical axis C. Furthermore, when the exit pupil distance is L0, considering the overlap between the first pupil region 501 and the second pupil region 502 and the exit pupil in the imaging optical system, no pupil misalignment occurs between the entrance pupil at the entrance pupil distance Zs and the exit pupil in the imaging optical system. On the other hand, when the exit pupil distance is L1, a pupil misalignment of amount P1 occurs between the entrance pupil at the entrance pupil distance Zs and the exit pupil in the imaging optical system. Furthermore, when the exit pupil distance is L2, a pupil misalignment of amount P2 occurs between the entrance pupil at the entrance pupil distance Zs and the exit pupil in the imaging optical system. In other words, if the exit pupil distance is different from the entrance pupil distance Zs, a pupil misalignment occurs between the entrance pupil at the entrance pupil distance Zs and the exit pupil in the imaging optical system.

[0026] If the pupil misalignment between the entrance pupil and the exit pupil in the imaging optical system becomes large, the baseline length may not be secured, and the focus detection performance of phase-difference AF may decrease. Therefore, in this embodiment, the image sensor 107 is configured so that the amount of pupil misalignment is suppressed with respect to the exit pupil distance, which changes according to the image height. More specifically, the image sensor 107 is configured so that the entrance pupil of the image sensor 107 is set within a predetermined threshold with respect to the exit pupil distance of the imaging optical system, which changes according to the image height.

[0027] Figure 9 shows the relationship between image height and exit pupil angle for a specific lens. Examples of specific lenses include seagull lenses, which exhibit a large change in exit pupil angle depending on the image height. This section describes a specific type of lens. Smartphones and similar devices use cameras with small sensors (less than 1 / 2 inch) and wide-angle lenses with bright aperture values ​​(F-numbers). Such cameras employ lenses sometimes called "seagull lenses," which have a large difference in exit pupil distance between the central image height (image height near the center of the lens) and the peripheral image height (image height away from the center). While the overall exit pupil distance is designed to be short to achieve camera miniaturization, the exit pupil distance at the peripheral image height is designed to be very long relative to the central image height to suppress excessive shading. As a result, this lens exhibits a large change in exit pupil distance with respect to changes in image height and has an aspherical shape.

[0028] One method for achieving camera miniaturization and improved image quality is to design the exit pupil distance of the photographic lens such that it has the relationship between image height and exit pupil angle shown in Figure 9. In the example shown in Figure 9, the change in the exit pupil angle in response to image height is large up to the intermediate image height, while the change in the exit pupil angle in response to image height is small from the intermediate image height to the high image height, resulting in a small difference in the exit pupil angle between the intermediate and high image heights. More specifically, at image heights up to the intermediate image height, the slope of the exit pupil angle with respect to image height is more than twice as steep as at image heights from the intermediate to the high image height. In this case, even when the distance between the photographic lens and the image sensor is narrow, the image sensor can receive light, thus achieving camera miniaturization and improved image quality. Furthermore, because the change in the exit pupil angle in response to image height from the intermediate to the high image height is small, the effect of shading (a phenomenon in which sensitivity decreases at high image heights on the screen, sometimes called peripheral light falloff, etc.) when used in combination with the image sensor 107 is mitigated.

[0029] In the image sensor 107, if each pixel 200 is designed such that the ratio of the amount of displacement R2 (see Figure 8) to the image height is constant, the entrance pupil distance Zs becomes uniform within the plane of the image sensor 107. When such an image sensor 107 with a uniform entrance pupil distance Zs is combined with a photographic lens having an exit pupil angle relationship corresponding to the image height as shown in Figure 9, an image height that results in large pupil displacement occurs. In particular, when the change in the exit pupil angle (the slope of the exit pupil angle relative to the image height) becomes more than twice as large at a predetermined image height, the occurrence of image heights with large pupil displacement becomes significant. Furthermore, at image heights with large pupil displacement, the phase-detection AF performance deteriorates. In imaging devices such as smartphones, focus detection is performed only at the widest aperture value, making it easier to secure the baseline length, and even if pupil displacement occurs, the tendency for phase-detection AF performance to deteriorate is small. On the other hand, in video recording devices used for film shooting, high-precision focus detection is required at any image height at small apertures, so it is necessary to suppress the deterioration of phase-detection AF performance. Therefore, in this embodiment, each pixel 200 of the image sensor 107 is designed so that, in the pupil division direction, the incident pupil distance changes according to the image height in accordance with the change in the exit pupil angle of the photographic lens according to the image height. More specifically, each pixel 200 of the image sensor 107 is designed so that the exit pupil distance and the incident pupil distance are the same at any given image height. In this way, even when a photographic lens is used that exhibits a large change in the exit pupil angle according to the image height, an image sensor is realized that reduces the effect of pupil misalignment and enables high-precision focus detection at any given image height.

[0030] Figure 10 shows the relationship between image height and displacement R2 when the incident pupil distance and exit pupil distance are equal, in the case where a photographic lens having the relationship between image height and exit pupil angle shown in Figure 9 is used. In this embodiment, the displacement amount R2 is determined in accordance with the change in the exit pupil angle according to the image height, as shown in Figure 9. More specifically, each pixel 200 of the image sensor 107 is designed such that the slope of the exit pupil angle with respect to the image height and the slope of the displacement amount R2 with respect to the image height are equal for each image height. Therefore, as shown in Figure 10, the change in the displacement amount R2 according to the image height is large at image heights up to the intermediate image height, while the change in the displacement amount R2 according to the image height is small at image heights from the intermediate image height to the high image height, so the difference in the displacement amount R2 between the intermediate image height and the high image height is small. In this way, the entrance pupil distance is determined to be equal to the exit pupil distance at any image height.

[0031] Figure 11 shows the relationship between the image height of the image sensor 107 and the change in the displacement amount R2 for an arbitrary image height R1. The change in the displacement amount R2 for an arbitrary image height R1 can be obtained by differentiating the slope of the displacement amount R2 shown in Figure 10 with respect to the image height. As shown in Figure 11, at image heights up to the intermediate image height, the change in the displacement R2 with respect to an arbitrary image height R1 is constant and is the first change. Furthermore, at image heights from the intermediate image height to the high image height, the change in the displacement R2 with respect to an arbitrary image height R1 is constant and is a second change, which is smaller than the first change. In this embodiment, as shown in Figure 10, the change in the displacement R2 with respect to image height is larger at image heights up to the intermediate image height than at image heights from the intermediate image height to the high image height. Therefore, the change in the displacement R2 with respect to an arbitrary image height R1 is larger at image heights up to the intermediate image height than at image heights from the intermediate image height to the high image height.

[0032] In this embodiment, in order to arrange a large number of pixels 200 on the image sensor 107, the photoelectric conversion unit is divided and arranged in the x-direction within the image sensor 107. Here, the horizontal direction (x-direction) where the number of pixels 200 is large is referred to as the long side direction of the image sensor 107. In order to increase the number of signals transmitted per transfer, or in other words, to improve the signal transfer efficiency, the long side direction of the image sensor 107 becomes the signal readout direction. Furthermore, in the image sensor 107 of this embodiment, since the photoelectric conversion unit is divided into a photoelectric conversion unit 301 and a photoelectric conversion unit 302 for each pixel 200, the number of readout signals is doubled compared to an image sensor 107 where the photoelectric conversion unit is not divided. Therefore, in this embodiment, the long side direction of the image sensor 107 and the signal readout direction are made to coincide. In other words, the pupil division direction of the image sensor 107 is made to coincide with the long side direction of the image sensor 107. Furthermore, in this embodiment, each pixel 200 is arranged such that microlenses 305 are formed at equal pitches in the short-side direction of the image sensor 107.

[0033] Figures 12(A) to 12(C) show the relationship between the change in the amount of displacement R2 and the image height R1 for every 200 pixels in the image sensor 107. As shown in Figures 12(A) to 12(C), the image sensor 107 is defined as having a first region 1201 where the change in R2 relative to the image height R1 is the first change (see Figure 11), and a second region 1202 where the change in R2 relative to the image height R1 is the second change. This means that for pixels 200 located in the first region 1201, the change in R2 relative to the image height R1 is the first change, and for pixels 200 located in the second region 1202, the change in R2 relative to the image height R1 is the second change. Furthermore, as shown in Figures 12(A) to 12(C), the image sensor 107 is defined as having either the first region 1201 or the second region 1202 depending on its position in the long side direction and the short side direction of the image sensor 107.

[0034] The relationship between the first region 1201 and the second region 1202 in the image sensor 107 is shown in Figure 12(A). In the example shown in Figure 12(A), the first region 1201 is defined as a predetermined radius range from the center of the image sensor 107, and the region outside the first region 1201 is defined as the second region 1202. In other words, in the example shown in Figure 12(A), the first region 1201 and the second region 1202 are determined by whether they are closer to the center of the image sensor 107 or outside the intermediate image height in the radial direction from the center of the image sensor 107. With the configuration shown in Figure 12(A), the first region 1201 and the second region 1202 are more easily compatible with photographic lenses in which the exit pupil angle is designed to be circularly symmetric with respect to the optical axis.

[0035] Furthermore, the relationship between the first region 1201 and the second region 1202 in the image sensor 107 is shown in Figure 12(B). In the example shown in Figure 12(B), the first region 1201 is defined as a rectangular region whose center coincides with the center of the image sensor 107, and the region outside the first region 1201 is defined as the second region 1202. This first region 1201 extends in the direction of the long side of the image sensor 107 rather than in the direction of the short side. The second region 1202 is located on both the outer sides of the first region 1201 in the direction of the long side and on both the outer sides of the short side. In addition, in the example shown in Figure 12(B), the intermediate image height in the direction of the long side of the image sensor 107 and the intermediate image height in the direction of the short side of the image sensor 107 are defined as boundaries. The first region 1201 and the second region 1202 are determined by whether the boundary is towards the center or outside the image sensor 107. Also, the intermediate image height in the short-side direction of the image sensor 107 is closer to the center of the image sensor 107 than the intermediate image height in the long-side direction of the image sensor 107. The configuration shown in Figure 12(B) simplifies the design of the image sensor 107 compared to the configuration shown in Figure 12(A) because the arrangement of pixels 200 in the image sensor 107 becomes easier.

[0036] Furthermore, the relationship between the first region 1201 and the second region 1202 in the image sensor 107 is shown in Figure 12(C). In the example shown in Figure 12(C), a rectangular region whose center coincides with the center of the image sensor 107 is defined as the first region 1201, and the region outside the first region 1201 is defined as the second region 1202. This first region 1201 extends in the direction of the short side of the image sensor 107 rather than in the direction of the long side. More specifically, the first region 1201 extends to the ends on both sides in the direction of the long side of the image sensor 107. The second region 1202 is located on both sides outside the first region 1201 in the direction of the long side, but not outside the first region 1201 in the direction of the short side. According to the configuration shown in Figure 12(C), the entrance pupil distance Zs is constant regardless of the image height in the direction of the short side of the image sensor 107. In the short-side direction of the image sensor 107, which is different from the pupil division direction, the high image height is shorter than in the long-side direction. Therefore, the accuracy of focus detection is less affected by the image height in the short-side direction, and thus, even with the configuration shown in Figure 12(C), the accuracy of focus detection can be ensured. Furthermore, the configuration shown in Figure 12(C) makes the design of the image sensor 107 even easier compared to the configuration shown in Figure 12(B).

[0037] Furthermore, due to manufacturing variations, individual differences in the image sensor 107 and photographic lens may occur. Taking this into consideration, if the entrance pupil distance Zs is set so that the exit pupil angle of the photographic lens is included in the angular range 602 (see Figure 8), an image sensor that can detect focus with high accuracy at any image height can be realized even if individual differences in the image sensor 107 and photographic lens occur.

[0038] Next, a modified example of the image sensor 107 will be described. Figure 13(A) is a plan view of pixel 200 in the image sensor 107 as a modified example, viewed from the light-receiving surface side (+z side) of the image sensor 107, and Figure 13(B) is a cross-sectional view of pixel 200 shown in Figure 13(A) as viewed from the -y side. Regarding the modified image sensor 107, a configuration different from that of the image sensor 107 described above will be explained, and the explanation of the configuration that is the same as that of the image sensor 107 described above will be omitted. As shown in Figure 13(B), in a modified image sensor 107, pixel 200 is provided with an intra-layer lens 1301 next to the microlens 305, below the microlens 305.

[0039] Figure 14 shows a modified example of the relationship between the entrance pupil of the image sensor 107 and the exit pupil of the imaging optical system. Figure 14 shows the optical axis 1401 of the intralayer lens 1301 in the target pixel 200, the central axis 1402 of the pixel 200 at image height R1, and the principal ray 1403 as the focus detection pixel in the pixel 200 at image height R1. Also in Figure 14, the principal ray 1404 as the imaging pixel in the pixel 200 at image height R1 is shown. Furthermore, Figure 14 shows the amount of displacement R3 between the central axis 603 of the divided region of the photoelectric conversion area and the optical axis 1401 in the target pixel 200, and the amount of displacement R4 between the optical axis 604 of the microlens 305 and the central axis 1402 in the target pixel 200.

[0040] As shown in Figure 14, in the modified image sensor 107, the central axis 603 of the pixel 200 is offset from the central axis 1402 of the pixel 200 in the pupil division direction. In other words, in the example shown in Figure 14, the pupil division pitch is greater than the pitch of the pixel 200 with respect to the change in image height of the image sensor 107. Also, in the modified image sensor, the central axis 603 and the central axis 1402 are offset in the pupil division direction for the pixels 200 of the image sensor 107, excluding the central pixel 200C. On the other hand, in the central pixel 200C, the central axis 603 and the central axis 1402 coincide in the pupil division direction. Furthermore, the principal ray 1403 as a focus detection pixel in the pixel 200 at image height R1 is determined according to the positional relationship between the central axis 603 and the optical axis 604. Furthermore, the principal ray 1404 as an imaging pixel in the pixel 200 at image height R1 is determined according to the positional relationship between the central axis 1402 and the optical axis 604.

[0041] As shown in Figure 14, if the central axes 603 and 1402 are offset in the pupil division direction at the target pixel 200, the angle between the principal ray 1403 as the focus detection pixel and the principal ray 1404 as the imaging pixel with respect to the optical axis 604 can be changed at any image height. In the illustrated example, since the amount of offset R4 is smaller than the amount of offset R2 with respect to the optical axis 604 of the microlens 305, the angle between the principal ray 1403 as the focus detection pixel and the optical axis 604 is larger than that between the principal ray 1404 as the imaging pixel and the optical axis 604.

[0042] When the angle between the principal ray 1403 as a focus detection pixel and the principal ray 1404 as an imaging pixel with respect to the optical axis 604 changes, it becomes easier to design the image sensor 107 with the imaging shading characteristics and the entrance pupil distance Zs independently. In the image sensor 107 shown in Figure 8, in order to change the entrance pupil distance Zs according to the image height, it is necessary to design each pixel 200 so that the pitch of the microlens 305 changes according to the image height. On the other hand, in the image sensor 107 shown in Figure 14, each pixel 200 is designed so that the pitch of the central axis 603 changes according to the image height. In this way, even if the pitch of the microlenses 305 is uniform regardless of the image height, the relationship between the image height and the amount of displacement R2 shown in Figure 10, and the relationship between the image height and the amount of displacement R2 with respect to the image height R1 shown in Figure 11 are realized. That is, a change in the entrance pupil distance Zs according to the image height is realized. Also, as in the image sensor 107 shown in Figure 14, when the pitch of the microlenses 305 is uniform regardless of the image height, shading unevenness in the image sensor 107 is less likely to occur. Shading unevenness is a phenomenon in which the shading change due to the image height becomes discontinuous even when a subject with uniform brightness is photographed. Shading unevenness is likely to occur when the pitch of the microlenses 305 changes according to the image height. However, there are limits to changing the angle between the principal rays 1403 as a focus detection pixel and the principal rays 1404 as an imaging pixel with respect to the optical axis 604. Therefore, even when changing the angle between the principal ray 1403 as a focus detection pixel and the principal ray 1404 as an imaging pixel with respect to the optical axis 604, each pixel 200 may be designed to change the pitch of the microlens 305 according to the image height.

[0043] Next, we will explain the pitch of the intralayer lens 1301. The intralayer lens 1301 suppresses the decrease in sensitivity that occurs when the pixel 200 is miniaturized. The angle of the principal ray 1403 as a focus detection pixel with respect to the optical axis 604 is determined by the microlens 305. Therefore, while the intralayer lens 1301 assists in the light-gathering performance of the optical system of the pixel 200, its influence on adjusting the angle of the principal ray 1403 as a focus detection pixel with respect to the optical axis 604 is less than that of the microlens 305. Also, if the pitch of the intralayer lens 1301 is changed according to the image height of the image sensor 107, it may cause shading unevenness. For this reason, the pitch of the intralayer lens 1301 may be constant regardless of the image height.

[0044] Figure 15 shows a modified example of the relationship between the image height of the image sensor 107 and the change in the displacement amount R2 for an arbitrary image height R1. The relationship between the image height of the image sensor 107 and the change in the displacement amount R2 for any given image height R1 is not limited to the example shown in Figure 11. As shown in Figure 15, at image heights up to the intermediate image height, the change in the displacement R2 with respect to an arbitrary image height R1 is constant and is the first change. Furthermore, at image heights from the intermediate image height to the first image height, the change in the displacement R2 with respect to an arbitrary image height R1 is constant and is the third change, which is smaller than the first change. Furthermore, at image heights from the first image height to the second image height, the change in the displacement R2 with respect to an arbitrary image height R1 is constant and is the fourth change, which is smaller than the third change. Furthermore, at image heights from the second image height to the high image height, the change in the displacement R2 with respect to an arbitrary image height R1 is constant and is the second change, which is smaller than the fourth change.

[0045] Thus, by increasing the number of stages in which the amount of change in the displacement R2 for an arbitrary image height R1 differs compared to the configuration shown in Figure 11, and by making the difference in the amount of change in consecutive stages smaller than in the configuration shown in Figure 11, the range of change in the entrance pupil distance Zs with respect to the image height becomes smaller. In this case, the effect of shading unevenness is reduced compared to the configuration shown in Figure 11. The number of steps in which the amount of change in the displacement R2 for any given image height R1 differs can be any number. For example, there may be steps in which the amount of change in the displacement R2 for any given image height R1 differs to the extent that the amount of change in the displacement R2 for any given image height R1 approximates a continuous change for each step.

[0046] Figures 16(A) to 16(C) show the relationship between the change in the amount of displacement R2 with respect to the image height R1 for each of 200 pixels in the image sensor 107, corresponding to the configuration shown in Figure 15. As shown in Figures 16(A) to 16(C), the image sensor 107 has a first region 1201 (see Figure 12) and a second region 1202, as described above. Furthermore, the image sensor 107 has a third region 1501 where the change in R2 with respect to the image height R1 is the third change (see Figure 15), and a fourth region 1502 where the change in R2 with respect to the image height R1 is the fourth change. This means that for a pixel 200 located in the third region 1501, the change in R2 with respect to the image height R1 is the third change, and for a pixel 200 located in the fourth region 1502, the change in R2 with respect to the image height R1 is the fourth change. Furthermore, as shown in Figures 16(A) to 16(C), in the image sensor 107, one of the following regions is defined: the first region 1201, the second region 1202, the third region 1501, and the fourth region 1502, depending on the position of the image sensor 107 in the long side direction and the short side direction.

[0047] Note that the first region 1201 shown in Figure 16(A) is the same region as the first region 1201 shown in Figure 12(A). Also, the first region 1201 shown in Figure 16(B) is the same region as the first region 1201 shown in Figure 12(B). Furthermore, the first region 1201 shown in Figure 16(C) is the same region as the first region 1201 shown in Figure 12(C).

[0048] The relationship between the first region 1201, the third region 1501, the fourth region 1502, and the second region 1202 in the image sensor 107 is shown in Figure 16(A). In the example shown in Figure 16(A), the area from the center of the image sensor 107 with a radius larger than that of the first region 1201 is defined as the third region 1501, and the area from the center of the image sensor 107 with a radius larger than that of the third region 1501 is defined as the fourth region 1502. Furthermore, the area outside the fourth region 1502 is defined as the second region 1202. Furthermore, the relationship between the first region 1201, the third region 1501, the fourth region 1502, and the second region 1202 in the image sensor 107 is shown in Figure 16(B). In the example shown in Figure 16(B), the third region 1501 is provided on both outer sides in the long side direction and on both outer sides in the short side direction of the first region 1201. The fourth region 1502 is also provided on both outer sides in the long side direction and on both outer sides in the short side direction of the third region 1501. The fourth region 1501 extends to the tips on both sides in the short side direction of the image sensor 107. The second region 1202 is also provided on both outer sides in the long side direction of the fourth region 1502.

[0049] Furthermore, the relationship between the first region 1201, the third region 1501, the fourth region 1502, and the second region 1202 in the image sensor 107 is shown in Figure 16(C). In the example shown in Figure 16(C), the third region 1501 is located on both outer sides in the long-side direction of the first region 1201, and the fourth region 1502 is located on both outer sides in the long-side direction of the third region 1501. Also, the second region 1202 is located on both outer sides in the long-side direction of the fourth region 1502. In addition, the third region 1501, the fourth region 1502, and the second region 1202 all extend to the ends on both sides in the long-side direction of the image sensor 107.

[0050] As described above, the image sensor 107 of this embodiment is an image sensor 107 in which pixels 200 having a plurality of photoelectric conversion regions divided in the first direction are arranged in two dimensions, and the direction of the long side of the image sensor 107 coincides with the first direction. In the first direction, the amount of change in the image height, which is the distance from the center of the image sensor 107, of the displacement R2 between the optical axis 604 of the microlens 305 of the pixel 200 and the center of the divided region of the photoelectric conversion region is the first amount of change when the image height is on the side of the first predetermined image height that is closer to the center. The center of the divided region of the photoelectric conversion region can be said to be the central axis 603. In addition, the first predetermined image height can be said to be the intermediate image height in the direction of the long side of the image sensor 107. In the first direction, the amount of change in the image height, which is the distance from the center of the image sensor 107, of the displacement R2 is the second amount of change when the image height is outside the first predetermined image height, and the first amount of change is greater than the second amount of change. In this case, even when used in combination with a photographic lens that exhibits a large change in exit pupil distance depending on the image height, an image sensor 107 is provided that can detect focus with high accuracy at any image height.

[0051] Furthermore, in this embodiment, microlenses 305 are formed at equal pitches in the short-side direction of the image sensor 107. In this case, the design of the image sensor 107 becomes simpler compared to a configuration in which microlenses 305 are formed at different pitches in the short-side direction of the image sensor 107.

[0052] Furthermore, in this embodiment, for a pixel 200 located at a position offset in one direction from the center of the image sensor 107, the center of the divided region of the photoelectric conversion area coincides with the center of the pixel 200 in one direction (see Figure 8). An example of a pixel 200 located at a position offset in one direction from the center of the image sensor 107 is a pixel 200 different from the central pixel 200C (see Figure 8), such as the target pixel 200. In this case, the design of the pixel 200 becomes simpler compared to a configuration where the position of the center of the divided region of the photoelectric conversion area in one direction does not coincide with the center of the pixel 200.

[0053] Furthermore, in this embodiment, the center of the divided region of the photoelectric conversion area in a pixel 200 located offset in one direction from the center of the image sensor 107 is located on the opposite side from the center of the image sensor 107 in one direction from the center of the pixel 200 (see Figure 14). In this case, the angle between the principal ray 1403 as a focus detection pixel and the principal ray 1404 as an imaging pixel with respect to the optical axis 604 can be changed at any image height.

[0054] Furthermore, in this embodiment, in the radial direction of the image sensor 107, the amount of change in the image height, which is the distance from the center of the image sensor 107 to the displacement R2, is the first amount of change when the image height is on the center side of the first predetermined image height, and the second amount of change when the image height is on the outside side of the first predetermined image height. In this case, the boundary of the change amount is more easily corresponding to photographic lenses in which the exit pupil angle is designed to be circularly symmetric with respect to the optical axis.

[0055] Furthermore, in this embodiment, in the short-side direction of the image sensor 107, the amount of change in the image height, which is the distance from the center of the image sensor 107 to the displacement R2, is the first amount of change when it is closer to the center than the second predetermined image height, and the second amount of change when it is outside the second predetermined image height. The second predetermined image height is closer to the center of the image sensor 107 than the first predetermined image height (see Figures 12(B) and 16(B)). In this case, the arrangement of pixels 200 on the image sensor 107 becomes easier compared to a configuration in which the amount of change is determined according to the image height in the radial direction of the image sensor 107.

[0056] Furthermore, in this embodiment, the amount of change in the displacement R2 in the short-side direction of the image sensor 107 with respect to the change in image height, which is the distance from the center of the image sensor 107, is the first amount of change regardless of the image height (see Figures 12(C) and 16(C)). In this case, the arrangement of pixels 200 on the image sensor 107 becomes easier while ensuring the accuracy of focus detection.

[0057] Furthermore, in this embodiment, the camera 1 is further equipped with a photographic lens in which, at image heights closer to the center than a first predetermined image height, the inclination of the exit pupil angle with respect to the image height is at least twice as much as at image heights further outside the first predetermined image height (see Figure 9). Examples of photographic lenses include a seagull lens. In this case, even with a camera 1 configuration where the occurrence of image heights with large pupil misalignment becomes significant, a camera 1 is provided that can perform focus detection with high accuracy at any image height.

[0058] In this embodiment, the exit pupil angle and the sensor pupil angle have been described. However, in the image sensor 107, the difference between the exit pupil angle and the sensor pupil angle may be kept within a predetermined threshold.

[0059] Furthermore, in this embodiment, it has been explained that the image sensor 107 has pixels 200 arranged in the x direction. Here, each pixel 200 may be designed symmetrically in the x direction (left-right symmetry in Figure 8) with respect to the central pixel 200C (see Figure 8).

[0060] Furthermore, in this embodiment, it was explained that in the long-side direction of the image sensor 107, the central axis 603 of the divided region of the photoelectric conversion area in the pixel 200 does not coincide with the center of the pixel 200 (see Figure 14). In this case, each lens may be generated by shrinking a microlens array in which the center position of each microlens 305 coincides with the center position of the photoelectric conversion part of each pixel 200 by a certain ratio in the horizontal and vertical directions.

[0061] Furthermore, it has been explained that the image sensor 107 may be provided with an intralayer lens 1301. Here, the amount of change of the displacement R3 in response to the change in image height may be defined in the direction of the long side of the image sensor 107. More specifically, this amount of change may be the first amount of change on the side of the third predetermined image height that is closer to the center, and the second amount of change on the side that is further away from the third predetermined image height. In this case, the first predetermined image height and the third predetermined image height may be different.

[0062] Alternatively, each lens may be generated by shrinking a microlens array in which the center position of each microlens 305 coincides with the center position of the photoelectric conversion unit of each pixel 200 by a certain percentage in the horizontal and vertical directions.

[0063] Furthermore, in this embodiment, although the x-direction shown in Figure 2 is the direction of the long side of the image sensor 107 and the y-direction is the direction of the short side of the image sensor 107, the embodiment is not limited to this. In the image sensor 107, the length in the x-direction and the length in the y-direction may be the same.

[0064] Furthermore, the present invention can also be realized by supplying a program that implements one or more of the functions of this embodiment to the camera 1 via a network or storage medium, and by having one or more processors in the camera 1's computer read and execute the program. It can also be realized by a circuit (e.g., an ASIC) that implements one or more of the functions.

[0065] This embodiment includes the following configuration. (Composition 1) An image sensor in which pixels having multiple photoelectric conversion regions divided in the first direction are arranged in a two-dimensional manner, The direction of the longer side of the image sensor coincides with the first direction. In the first direction, the amount of change in the amount of displacement between the optical axis of the microlens of the pixel and the center of the divided region of the photoelectric conversion area with respect to the change in image height, which is the distance from the center of the image sensor, is a first amount of change when the image height is closer to the center than a first predetermined image height, and a second amount of change when the image height is further away from the first predetermined image height. The image sensor is characterized in that the first amount of change is greater than the second amount of change. (Configuration 2) The image sensor according to claim 1, characterized in that the microlenses are formed at equal pitches in the short-side direction of the image sensor. (Composition 3) The image sensor according to claim 1, wherein, in a pixel located at a position offset in one direction from the center of the image sensor, the center of the divided region of the photoelectric conversion area coincides with the center of the pixel in that direction. (Composition 4) The image sensor according to claim 1, characterized in that the center of the divided region of the photoelectric conversion area in the pixel located at a position offset in one direction from the center of the image sensor is located on the opposite side from the center of the image sensor in that one direction from the center of the pixel. (Composition 5) The image sensor according to claim 1, characterized in that, in the radial direction of the image sensor, the amount of change is the first amount of change on the central side of the first predetermined image height, and the amount of change outside the first predetermined image height. (Composition 6) In the short-side direction of the image sensor, the amount of change is the first amount of change when it is closer to the center than the second predetermined image height, and the second amount of change when it is outside the second predetermined image height. The image sensor according to claim 1, characterized in that the second predetermined image height is closer to the center of the image sensor than the first predetermined image height. (Composition 7) The image sensor according to claim 1, characterized in that the amount of change in the short-side direction of the image sensor is the first amount of change regardless of the image height. (Composition 8) An image sensor according to any one of claims 1 to 7, Processing means for processing the signal output from the image sensor, An imaging device characterized by comprising: (Composition 9) The imaging apparatus according to configuration 8, further comprising a photographic lens in which, at an image height closer to the center than the first predetermined image height, the inclination of the exit pupil angle with respect to the image height is twice or more compared to the image height outside the first predetermined image height.

[0066] Although the present invention has been described in detail above based on its preferred embodiments, the present invention is not limited to the above embodiments, and various modifications are possible in accordance with the spirit of the present invention, and these modifications are not excluded from the scope of the present invention. [Explanation of symbols]

[0067] 1...Camera, 107...Image sensor, 200...Pixels, 305...Microlenses

Claims

1. An image sensor in which pixels having multiple photoelectric conversion regions divided in the first direction are arranged in a two-dimensional manner, The direction of the longer side of the image sensor coincides with the first direction. In the first direction, the amount of change in the amount of displacement between the optical axis of the microlens of the pixel and the center of the divided region of the photoelectric conversion area with respect to the change in image height, which is the distance from the center of the image sensor, is a first amount of change when the image height is closer to the center than a first predetermined image height, and a second amount of change when the image height is further away from the first predetermined image height. The image sensor is characterized in that the first amount of change is greater than the second amount of change.

2. The image sensor according to claim 1, characterized in that the microlenses are formed at equal pitches in the short-side direction of the image sensor.

3. The image sensor according to claim 1, wherein, in a pixel located at a position offset in one direction from the center of the image sensor, the center of the divided region of the photoelectric conversion area coincides with the center of the pixel in that direction.

4. The image sensor according to claim 1, characterized in that the center of the divided region of the photoelectric conversion area in the pixel located at a position offset in one direction from the center of the image sensor is located on the opposite side from the center of the image sensor in that one direction from the center of the pixel.

5. The image sensor according to claim 1, characterized in that, in the radial direction of the image sensor, the amount of change is the first amount of change on the central side of the first predetermined image height, and the amount of change outside the first predetermined image height.

6. In the short-side direction of the image sensor, the amount of change is the first amount of change when it is closer to the center than the second predetermined image height, and the second amount of change when it is outside the second predetermined image height. The image sensor according to claim 1, characterized in that the second predetermined image height is closer to the center of the image sensor than the first predetermined image height.

7. The image sensor according to claim 1, characterized in that the amount of change in the short-side direction of the image sensor is the first amount of change regardless of the image height.

8. An image sensor according to any one of claims 1 to 7, Processing means for processing the signal output from the image sensor, An imaging device characterized by comprising:

9. The imaging apparatus according to claim 8, further comprising a photographic lens in which, at an image height closer to the center than the first predetermined image height, the inclination of the exit pupil angle with respect to the image height is twice or more compared to the image height outside the first predetermined image height.

Images