JP6391306B2 - IMAGING DEVICE, IMAGING DEVICE CONTROL METHOD, PROGRAM, AND STORAGE MEDIUM - Google Patents

Description

  The present invention relates to an image pickup apparatus including an image pickup element including a focus detection pixel.

  2. Description of the Related Art Conventionally, a focus detection device (imaging device) that performs focus detection by a pupil division method by arranging a microlens at each pixel of an image sensor is known. In the pupil division method, focus detection is performed using a part of the effective light flux of the photographing lens.

  Patent Document 1 discloses a focus detection device that performs focus detection based on a correlation amount of at least one focus detection pixel among a plurality of focus detection pixels having different baseline lengths. Patent Document 2 discloses a focus detection device in which a plurality of divided pixels are arranged so as to correspond to one microlens and the divided pixels corresponding to the aperture information of the photographing lens are used.

JP 2005-106994 A JP 2007-133087 A

  However, in the focus detection apparatus of Patent Document 1, mask processing is performed on the sensor in order to perform pupil division. In such a configuration, since the light is shielded by the masking process, the ratio of the light flux that cannot be captured by the sensor increases, and some pixels cannot be used as imaging pixels. Moreover, in the focus detection apparatus of Patent Document 2, since three or more pixels are arranged so as to correspond to one microlens, the number of divided pixels increases. For this reason, it is necessary to densely arrange circuits for extracting electric signals from the respective divided pixels, which complicates the circuit.

  Therefore, the present invention provides an imaging apparatus that performs pupil-division focus detection, a method for controlling the imaging apparatus, a program, and a storage medium that can easily secure a sufficient amount of light.

An imaging device according to one aspect of the present invention includes: a first pixel divided at a first area ratio; and a second pixel divided at a second area ratio different from the first area ratio. an imaging element containing, obtained from the output signal of the imaging element, by using a plurality of pupil division signals corresponding to the light beams passing through different divided pupil areas of the photographing optical system, have a focus detection means for performing focus detection The focus detection unit passes through an output signal of one divided pixel included in the first pixel and a pupil partial region overlapping with the one divided pixel among the divided pixels included in the second pixel. Focus detection is performed by using a difference signal between the divided signal having the received light flux and the divided pixel having a light receiving area different from that of the one divided pixel as the pupil divided signal .

According to another aspect of the present invention, there is provided a method for controlling an imaging apparatus, the first pixel divided by the first area ratio, and the second pixel divided by a second area ratio different from the first area ratio. obtained from the output signal of the image pickup element including two pixels, using a plurality of pupil division signals corresponding to the light beams passing through different divided pupil areas of the photographing optical system, a control method of an image pickup apparatus which performs focus detection And receiving a light beam that has passed through an output signal of one divided pixel included in the first pixel and a pupil partial region overlapping with the one divided pixel among the divided pixels included in the second pixel. And calculating a difference between the one divided pixel and an output signal of a divided pixel having a different light receiving area, and performing the focus detection using the difference as the pupil divided signal .

A program according to another aspect of the present invention includes: a first pixel divided at a first area ratio; and a second pixel divided at a second area ratio different from the first area ratio. obtained from the output signal of the imaging element comprising, using a plurality of pupil division signals corresponding to the light beams passing through different divided pupil areas of the photographing optical system, a program for performing focus detection, the first Among the divided pixels included in the second pixel, the output signal of one divided pixel included in the pixel and the light beam that has passed through the pupil partial region overlapping with the one divided pixel are received and the one divided pixel And a step of calculating a difference between the output signals of the divided pixels having different light receiving areas and a step of performing the focus detection using the difference as the pupil division signal .

  A storage medium according to another aspect of the present invention stores the program.

  Other objects and features of the present invention are illustrated in the following examples.

  ADVANTAGE OF THE INVENTION According to this invention, the imaging device which performs the focus detection of a pupil division system which can ensure sufficient light quantity easily, the control method of an imaging device, a program, and a storage medium can be provided.

FIG. 3 is a cross-sectional view of an image sensor in Example 1. 3 is a cross-sectional view of a divided pixel in Example 1. FIG. It is explanatory drawing of the pupil division of the division pixel in Example 1. FIG. It is explanatory drawing of the 4-part dividing pixel and pupil division as a comparative example. FIG. 3 is a pixel array diagram of an image sensor in Embodiment 1. FIG. 6 is a pixel array diagram of an image sensor in Embodiment 2. It is explanatory drawing of the 5-part dividing pixel as a comparative example. 10 is an explanatory diagram of an array of divided pixels in Embodiment 3. FIG. 10 is an explanatory diagram of an array of divided pixels in Embodiment 4. FIG. FIG. 3 is a pixel array diagram of an image sensor in Embodiment 1. It is a block diagram of the imaging device in each Example.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  First, with reference to FIG. 11, the imaging device in the present embodiment will be described. FIG. 11 is a configuration diagram of the imaging apparatus 100 (imaging system). In the imaging apparatus 100, an imaging apparatus main body (camera main body) including an imaging element 107 and a photographing optical system (photographing lens) are integrally configured. However, the present embodiment is not limited to this, and can also be applied to an imaging system that includes an imaging apparatus main body and a lens device (imaging optical system) that can be attached to and detached from the imaging apparatus main body.

  In FIG. 11, reference numeral 101 denotes a first lens group. The first lens group 101 is disposed at the tip of the photographing optical system (imaging optical system), and is held so as to be able to advance and retreat in the direction of the optical axis OA (optical axis direction). Reference numeral 102 denotes an aperture / shutter. The diaphragm / shutter 102 adjusts the light amount at the time of photographing by adjusting the aperture diameter. The aperture / shutter 102 has a function as an exposure time adjustment shutter when taking a still image. Reference numeral 103 denotes a second lens group constituting the photographing optical system. The diaphragm / shutter 102 and the second lens group 103 integrally move forward and backward in the optical axis direction, and perform a zooming function (zoom function) in conjunction with the forward / backward movement of the first lens group 101. Reference numeral 105 denotes a third lens group constituting the photographing optical system. The third lens group 105 performs focus adjustment by moving back and forth in the optical axis direction. Reference numeral 106 denotes an optical low-pass filter. The optical low-pass filter 106 is an optical element for reducing false colors and moire in the captured image.

  Reference numeral 107 denotes an image sensor. The image sensor 107 photoelectrically converts a subject image (optical image) obtained via the photographing optical system and outputs an image signal. The image sensor 107 includes a C-MOS sensor and its peripheral circuit. The image sensor 107 uses a two-dimensional single-plate color sensor in which a Bayer array primary color mosaic filter is formed on-chip on light receiving pixels of m pixels in the horizontal direction and n pixels in the vertical direction. The image sensor 107 includes a plurality of focus detection pixels (focus detection pixel group) and a plurality of imaging pixels (imaging pixel group). The plurality of focus detection pixels receive light beams that pass through different pupil regions of the photographing optical system and output image signals. The plurality of imaging pixels receive a light beam that has passed through the same pupil region of the imaging optical system and output an image signal.

  Reference numeral 111 denotes a zoom actuator. The zoom actuator 111 rotates a cam cylinder (not shown) to drive the first lens group 101, the second lens group 103, and the third lens group 105 forward and backward in the optical axis direction, and performs a zooming operation. . Reference numeral 112 denotes an aperture shutter actuator. The aperture shutter actuator 112 controls the aperture diameter of the aperture / shutter 102 to adjust the amount of photographing light, and also controls the exposure time when taking a still image. Reference numeral 114 denotes a focus actuator. The focus actuator 114 performs focus adjustment by driving the third lens group 105 (focus lens) forward and backward in the optical axis direction.

  Reference numeral 115 denotes an electronic flash (illuminating means) for illuminating the subject at the time of shooting. As the electronic flash 115, a flash illumination device using a xenon tube is suitable, but an illumination device including LEDs that emit light continuously may be used. Reference numeral 116 denotes AF auxiliary light means. The AF auxiliary light means 116 projects a mask image having a predetermined aperture pattern onto the object field via the light projection lens, and improves the focus detection capability for a dark subject or a low-contrast subject.

  Reference numeral 121 denotes a CPU (control device). The CPU 121 is a camera CPU (camera control unit) that controls various controls of the camera body, and includes a calculation unit, a ROM, a RAM, an A / D converter, a D / A converter, a communication interface circuit, and the like. The CPU 121 drives various circuits of the camera body based on a predetermined program stored in the ROM, and executes a series of operations such as AF, shooting, image processing, and recording. In this embodiment, the CPU 121 functions as a focus detection unit that performs focus detection based on an output signal from the image sensor 107. The specific operation of the focus detection unit will be described later.

  Reference numeral 122 denotes an electronic flash control circuit. The electronic flash control circuit 122 controls lighting of the electronic flash 115 in synchronization with the photographing operation. Reference numeral 123 denotes an auxiliary light driving circuit. The auxiliary light driving circuit 123 controls lighting of the AF auxiliary light unit 116 in synchronization with the focus detection operation. Reference numeral 124 denotes an image sensor driving circuit. The image sensor driving circuit 124 controls the image capturing operation of the image sensor 107 and A / D converts the image signal output from the image sensor 107 and transmits the image signal to the CPU 121. Reference numeral 125 denotes an image processing circuit. The image processing circuit 125 performs image processing such as γ conversion, color interpolation, and JPEG compression on the image signal obtained from the image sensor 107.

  Reference numeral 126 denotes a focus driving circuit. The focus drive circuit 126 controls the focus actuator 114 based on the focus detection result, and adjusts the focus by driving the third lens group 105 back and forth in the optical axis direction. Reference numeral 128 denotes an aperture shutter drive circuit. The aperture shutter drive circuit 128 controls the aperture of the aperture / shutter 102 by drivingly controlling the aperture shutter actuator 112. Reference numeral 129 denotes a zoom drive circuit. The zoom drive circuit 129 drives the zoom actuator 111 according to the zoom operation of the photographer.

  Reference numeral 131 denotes a display such as an LCD. The display 131 displays information related to the shooting mode of the camera body, a preview image before shooting and a confirmation image after shooting, a focus state display image at the time of focus detection, and the like. Reference numeral 132 denotes an operation switch group. The operation switch group 132 includes a power switch, a release (shooting trigger) switch, a zoom operation switch, a shooting mode selection switch, and the like. Reference numeral 133 denotes a detachable flash memory. The flash memory 133 records captured images.

  Next, an image sensor according to Example 1 of the present invention will be described. FIG. 1 is a cross-sectional view of the image sensor 107 in the present embodiment. The image sensor 107 is configured by two-dimensionally arranging a plurality of microlenses 10 and a plurality of pixels (photoelectric conversion units). In the imaging element 107, one microlens 10 and one pixel 12 (a photoelectric conversion unit that is a light receiving element) are provided so as to correspond to each other.

  FIG. 10 is a pixel array diagram of the image sensor 107 in the present embodiment. As shown in FIG. 10, a plurality of pixels 12 (photographing pixels) having an RGB Bayer array are two-dimensionally arranged on the image sensor 107. In the image sensor 107, a plurality of divided pixels 12a, 12b, and 12c (focus detection pixels) used for focus detection are arranged in a partial region of the plurality of RGB pixels. As shown in FIG. 10, the image sensor 107 of the present embodiment includes three divided pixels 12a, 12b, and 12c having different types, that is, different division ratios. However, the image sensor 107 of the present embodiment is not limited to this, and may be configured to include four or more types of divided pixels.

  2A to 2C are cross-sectional views of the divided pixels 12a, 12b, and 12c of the image sensor 107. FIG. As shown in FIG. 2A, the divided pixel 12a is two divided pixels S3 and S4 obtained by dividing the normal photographing pixel 12 at an equal ratio of an area ratio of 1: 1. The two divided pixels S3 and S4 are configured to share one microlens 10. As shown in FIG. 2B, the divided pixel 12b is two divided pixels S1 and S2 obtained by dividing the normal photographing pixel 12 at an unequal ratio of an area ratio of 1: 3. The two divided pixels S <b> 1 and S <b> 2 are configured to share one microlens 10. As shown in FIG. 2C, the divided pixel 12c is two divided pixels S5 and S6 obtained by dividing the normal photographing pixel 12 at an unequal ratio of an area ratio of 3: 1. The two divided pixels S5 and S6 are configured to share one microlens 10.

  Subsequently, with reference to FIGS. 3A to 3C, three types of divided pixels 12a, 12b, and 12c shown in FIGS. 2A to 2C are formed via the microlens 10. FIG. The entrance pupil will be described. FIG. 3A is a conceptual diagram of an entrance pupil of pixels that are arranged in the vicinity of the center of the photographing screen and whose area ratio is equally divided. The position of the entrance pupil is determined by the power of the microlens 10 and the eccentricity of the lens and the pixel. The division of the luminous flux of the pupil is determined according to the division of the pixels. When the pixels are divided equally, the pupil is divided equally. In FIG. 3A, since the area ratio of the divided pixels S3 and S4 is 1: 1 (S3: S4 = 1: 1), the area on the pupil is also divided by 1: 1 (divided pupil PS3). , PS4).

  FIGS. 3B and 3C are conceptual diagrams of the entrance pupil in the non-uniformly divided pixels. The luminous flux captured by the divided pixels is determined according to the area of the divided pixels, as in the case of the equally divided pixels. In FIG. 3B, since the area ratio of the divided pixels S1 and S2 is 1: 3 (S1: S2 = 1: 3), the area on the pupil is also divided by 1: 3 (divided pupil PS1). , PS2). In FIG. 3C, since the area ratio of the divided pixels S5 and S6 is 3: 1 (S5: S6 = 3: 1), the area on the pupil is also divided by 3: 1 (divided pupil PS5). , PS6).

  In this embodiment, the non-uniformly divided pixels (divided pixels S1, S2, S5, S6) are arranged adjacent to the above-described equally divided pixels (divided pixels S3, S4) on the imaging surface. ing. For this reason, the position of the entrance pupil of the non-uniformly divided pixels (divided pixels S1, S2, S5, S6) is substantially the same as the pupil position of the equally divided pixels (divided pixels S3, S4). In addition, when the position of the entrance pupil is shifted due to the fact that the equally divided pixels and the unevenly divided pixels cannot be arranged adjacent to each other, the microlens 10 is decentered to change the position of the entrance pupil. It is preferable to set so that they are aligned.

  In this embodiment, by taking a difference between the output values (pixel values) of two specific divided pixels among a plurality of divided pixels, the pixel is divided into four even though the number of divisions is two. The same pupil division can be performed. FIG. 4A is a plan view of the four-divided pixels A to D. FIG. FIG. 4B is an explanatory diagram of pupil division of the four-divided pixels A to D, and shows pupils (divided pupils PA to PD) divided by the divided pixels. In the present embodiment, each of the outputs of the divided pixels S1 to S6 is used alone, or by using the difference between the outputs of two divided pixels among these divided pixels, the pupil division (divided pupils PA˜ PD).

  The divided pupils PA and PD in FIG. 4B can be expressed by the outputs of the single divided pixels S1 and S6 because A = S1 and D = S6 are established. On the other hand, the divided pupils PB and PC cannot be expressed by the output of a single divided pixel. For this reason, in this embodiment, by calculating the difference between the outputs of the divided pixels S1 to S6 (B = S3-S1 (or B = S2-S4), C = S4-S6 (or C = S5-S3)), The divided pupils PB and PC are expressed respectively.

  Next, the pixel arrangement of the divided pixels S1 to S6 will be described with reference to FIG. FIG. 5 is a pixel arrangement diagram of divided pixels S1 to S6 (focus detection pixels) and photographing pixels, and shows a part of a pixel group included in the image sensor 107 in an enlarged manner. In the present embodiment, a Bayer array is adopted as the pixel array of the image sensor 107 arranged in the vicinity of the planned imaging plane of the photographing lens (shooting optical system). The Bayer array image sensor 107 has three types of filters of R (red), G (green), and B (blue), and four RGB pixels (photographing pixels) are regularly arranged. In these photographic pixels, divided pixels S1 to S6 (focus detection pixels) for performing focus detection are mixedly arranged.

  In this embodiment, as shown in FIG. 5 and FIG. 10, focus detection pixels (divided pixels 12 a to 12 c) are arranged adjacent to each other as three of the four pixels that are the basic unit of the Bayer array. Yes. In the configuration of FIG. 10, the units (a set of divided pixels 12a to 12c (S1 to S6)) constituting the focus detection pixels are arranged in the horizontal direction at intervals of 4 units of the Bayer array. An output signal is read out. The output signals of the divided pixels S1 to S6 become a one-dimensional output signal for each divided pixel independently for each of the divided pixels S1 to S6. Then, the CPU 121 of the imaging apparatus 100 performs a correlation operation on an image shift amount of an output signal corresponding to an optical image obtained through two different pupils (two divided pupil regions) of the photographing lens (imaging optical system). The focus position (defocus amount) of the photographing lens can be calculated.

  In the present embodiment, the CPU 121 of the imaging apparatus 100 performs focus detection suitable for the photographing lens by arbitrarily selecting the output of the divided pixels S1 to S6 or the output difference according to the light flux state of the photographing lens. Can do. For example, when Fno (aperture value) of the photographic lens is bright (small), correlation calculation of image shift is performed based on the output signals (pixel values) of the divided pixels S1 and S6 having a long base line length, and the defocus amount of the photographic lens Is calculated. On the other hand, when the Fno of the photographic lens is dark (large), the difference between the output signals of the divided pixels S2 and S4 with a short baseline length “S2 to S4” and the difference between the output signals of the divided pixels S5 and S3 “S5 to S3”. The image shift correlation calculation is performed based on the above, and the defocus amount of the photographing lens is calculated.

  Further, the imaging apparatus 100 according to the present exemplary embodiment can perform focus detection suitable for the exit pupil position of the photographing lens. For example, when the pupil of the taking lens is close, the correlation calculation of the image shift is performed based on the output signal of the divided pixel S1 and the difference signal “S4-S6” of the divided pixels S4 and S6, and the defocus amount of the taking lens is calculated. . On the other hand, when the pupil of the taking lens is far, the image shift correlation calculation is performed based on the difference signal “S3-S1” of the divided pixels S3 and S1 and the output signal of the divided pixel S6, and the defocus amount of the taking lens is calculated. .

  As described above, in this embodiment, the image sensor 107 includes the first pixel group (for example, the divided pixel 12b) divided at the first area ratio, and the second area ratio different from the first area ratio. The second pixel group (for example, the divided pixel 12a) divided by. Further, the CPU 121 (focus detection means) outputs the output signal of the first pixel (for example, the divided pixel S1) included in the first pixel group and the second pixel (for example, the divided pixel) included in the second pixel group. Focus detection is performed based on the difference from the output signal of S3).

  Preferably, the image sensor 107 further includes a third pixel group (for example, a divided pixel 12c) divided by the third area ratio. The first pixel group includes a first divided pixel (divided pixel S1) and a second divided pixel (divided pixel S2) having a first area ratio of 1: 3. The second pixel group includes a third divided pixel (divided pixel S3) and a fourth divided pixel (divided pixel S4) having a second area ratio of 1: 1. The third pixel group includes a fifth divided pixel (divided pixel S5) and a sixth divided pixel (divided pixel S6) having a third area ratio of 3: 1.

  Preferably, the CPU 121 can acquire the output signal of the first divided pixel as the first pupil divided signal (focus detection signal from the divided pupil PS1). Further, the CPU 121 determines the difference (S3−S1) between the output signal of the third divided pixel and the output signal of the first divided pixel, or the output signal of the second divided pixel and the output signal of the fourth divided pixel. Is obtained as a second pupil division signal (focus detection signal from the division pupil PS2). Further, the CPU 121 determines the difference between the output signal of the fourth divided pixel and the output signal of the sixth divided pixel (S4-S6), or the output signal of the fifth divided pixel and the output signal of the third divided pixel. Is obtained as a third pupil division signal (focus detection signal from the division pupil PS3). In addition, the CPU 121 acquires the output signal of the sixth divided pixel as the fourth pupil divided signal (focus detection signal from the divided pupil PS4). More preferably, the CPU 121 performs focus detection based on at least two of the first pupil division signal, the second pupil division signal, the third pupil division signal, and the fourth pupil division signal.

  Preferably, the CPU 121 selects the first pupil division signal, the second pupil division signal, the third pupil division signal, which are selected according to the aperture value (F value: Fno) or the pupil position (exit pupil position). And focus detection is performed based on at least two of the fourth pupil division signals. More preferably, when the aperture value is equal to or smaller than the predetermined aperture value, the CPU 121 performs focus detection based on the first pupil division signal and the fourth pupil division signal. On the other hand, when the aperture value is larger than the predetermined aperture value, the CPU 121 performs focus detection based on the second pupil division signal and the third pupil division signal. More preferably, when the pupil position is closer to the image sensor 107 than the predetermined pupil position, the CPU 121 performs focus detection based on the first pupil division signal and the third pupil division signal. On the other hand, when the pupil position is farther from the image sensor 107 than the predetermined pupil position, the CPU 121 performs focus detection based on the second pupil division signal and the fourth pupil division signal.

  As described above, according to the configuration of the present embodiment, by using the difference signal of a plurality of divided pixels obtained by dividing a normal shooting pixel with different areas, the complexity of the pixel circuit due to multi-division is reduced. The pupil division similar to the case where multi-divided pixels are employed is possible.

  Next, with reference to FIG. 6 and FIG. 7, an image sensor according to the second embodiment of the present invention will be described. FIG. 6 is a pixel array diagram of the image sensor in the present embodiment. FIG. 7 is a plan view of five-divided pixels A to E as comparative examples.

  As shown in FIG. 6, the image sensor of the present embodiment includes divided pixels 12 d and 12 e. The divided pixel 12d is configured by divided pixels S1 to S3 obtained by dividing the photographing pixel into three. The divided pixel 12e is composed of divided pixels S4 to S6 obtained by dividing the shooting pixel into three. The areas of the divided pixels S1, S3, and S5 are equal to each other. The areas of the divided pixels S4 and S6 are equal to each other and have twice the area of each of the divided pixels S1, S3, and S5. The area of the divided pixel S2 is three times that of each of the divided pixels S1, S3, and S5. As described above, the focus detection pixel of this embodiment is a three-divided pixel obtained by dividing the photographing pixel into three.

  When the focus detection pixel having three-divided pixels is provided as in the present embodiment, an effect can be obtained as in the case where the five-divided pixel shown in FIG. That is, if the output signals (pixel values) of the divided pixels S1 to S6 are used alone or a specific two output signals of these divided pixels are used as a difference, A = S1, B = S4-S1, C = S5, D = S6-S3, E = S3. For this reason, signals equivalent to the output signals of the divided pixels A to E shown in FIG. 7 can be obtained by using the divided pixels S1 to S6 of this embodiment.

  As described above, in this embodiment, the image sensor 107 includes the first pixel group (for example, the divided pixel 12d) divided at the first area ratio, and the second area ratio different from the first area ratio. The second pixel group (for example, the divided pixel 12e) divided by. The CPU 121 (focus detection means) outputs the output signal of the first pixel (for example, the divided pixel S1) included in the first pixel group and the second pixel (for example, the divided pixel S4) included in the second pixel group. Focus detection is performed based on the difference from the output signal.

  Preferably, the first pixel group includes a first divided pixel (divided pixel S1), a second divided pixel (divided pixel S2), and a third area ratio of 1: 3: 1. It has a divided pixel (divided pixel S3). The second pixel group includes a fourth divided pixel (divided pixel S4), a fifth divided pixel (divided pixel S5), and a sixth divided pixel (with a second area ratio of 2: 1: 2). It has a divided pixel S6).

  Preferably, CPU121 acquires the output signal of the 1st division pixel as the 1st pupil division signal. Further, the difference between the output signal of the fourth divided pixel and the output signal of the first divided pixel is acquired as the second pupil divided signal. Further, the output signal of the fifth divided pixel is acquired as the third pupil divided signal. Further, the difference between the output signal of the sixth divided pixel and the output signal of the third divided pixel is acquired as the fourth pupil divided signal. Further, the output signal of the third divided pixel is acquired as the fifth pupil division signal. More preferably, the CPU 121 is based on at least two of the first pupil division signal, the second pupil division signal, the third pupil division signal, the fourth pupil division signal, and the fifth pupil division signal. Perform focus detection. More preferably, the CPU 121 selects the first pupil division signal, the second pupil division signal, the third pupil division signal, the fourth pupil division signal, and the selected pupil division signal according to the aperture value or the pupil position. Focus detection is performed based on at least two of the fifth pupil division signals.

  Next, with reference to FIG. 8, an image sensor according to Example 3 of the present invention will be described. FIG. 8 is an explanatory diagram of the pixel arrangement of the image sensor 107 in the present embodiment, in the vertical area 1071 and the horizontal area 1072 with respect to the center of the imaging surface of the image sensor 107 (the optical axis of the imaging lens). The arrangement of divided pixels is shown.

  In the present embodiment, the divided pixels 12a to 12c (focus detection pixels) to be subjected to the difference calculation are arranged adjacent to each other and are concentric with the imaging element 107 (imaging surface) (based on the center of the imaging surface). (Circumferential direction) (disposed perpendicularly to the radial direction).

  The divided pixels S <b> 1 to S <b> 6 that are the targets of the difference calculation can be considered to have substantially the same light flux when located closer to each other on the imaging surface. For this reason, it is preferable that the divided pixels to be subjected to difference calculation are arranged so as to be closer to each other. More preferably, the divided pixels are arranged adjacent to each other. Even when the divided pixels are different by the same distance, the variation in aberration in the concentric direction is smaller than the variation in aberration due to a change in image height in the radial direction (concentric radial direction) of the image sensor. For this reason, it is preferable that the divided pixels are arranged along a concentric direction with less influence. As described above, in the present embodiment, the pixel group including the divided pixels for which the difference calculation is performed is preferably arranged along the concentric circle direction and close to each other.

  Next, with reference to FIG. 9, an image sensor according to Example 4 of the present invention will be described. FIG. 9 is an explanatory diagram of the pixel arrangement of the image sensor in the present embodiment, and the divided pixels 12f, 12g in the region 1073 diagonal to the center of the imaging surface of the image sensor 107 (the optical axis of the photographing lens). The 12h sequence is shown.

  The divided pixel 12f includes divided pixels S31 and S41 having an area ratio of 1: 1. The divided pixel 12g includes divided pixels S51 and S61 having an area ratio of 3: 1. The divided pixel 12h includes divided pixels S11 and S21 having an area ratio of 1: 3. As described above, the divided pixels 12f to 12h of the present embodiment have the divided pixels divided by the same area ratio as the divided pixels 12a to 12c of the first embodiment. However, unlike the first embodiment, the diagonal direction of the imaging surface It is divided in (diagonal direction).

  In the corner region (region in the four corner directions) of the image sensor 107 (imaging surface), there is a case where a margin in the radiation direction is reduced due to vignetting of the light flux of the photographing lens. In this case, since the concentric light beam has more margin than the radial light beam, pixel division in the concentric direction is effective. For this reason, the divided pixels S11 to S61 of the present embodiment are arranged along the concentric direction in a region 1703 diagonally with respect to the center of the imaging surface, and are divided and arranged in the diagonal direction of the imaging surface. ing. As described above, the focus detection pixels can be divided not only in the vertical direction and the horizontal direction as in the third embodiment, but also in an oblique direction (diagonal direction).

[Other Embodiments]
The present invention is also realized by executing the following processing. That is, software (program) that realizes the functions of the above-described embodiments is supplied to a system or apparatus via a network or various storage media, and the computer (or CPU, MPU, etc.) of the system or apparatus reads the program. To be executed. In this case, a computer-executable program describing the procedure of the imaging apparatus control method and a storage medium storing the program constitute the present invention.

  In each embodiment, preferably, the first pixel group and the second pixel group are arranged adjacent to each other. Preferably, the first pixel group and the second pixel group are arranged along a circumferential direction (concentric direction) with the center of the imaging surface of the imaging element 107 as a reference. Preferably, the first pixel group and the second pixel group are in a second direction orthogonal to the first direction (in a region located in the first direction with respect to the center of the imaging surface of the image sensor 107 ( It is arranged along the horizontal direction, the vertical direction, or). For example, when the first direction is the vertical direction, the horizontal direction, or the diagonal direction (first diagonal direction) with respect to the center of the imaging surface, the second direction is the horizontal direction, the vertical direction, or the diagonal direction, respectively. Direction (second oblique direction substantially orthogonal to the first oblique direction).

  According to the imaging device (focus detection device) of each embodiment, pupil division corresponding to the photographing lens can be performed without requiring a large number of divided pixels and masks. Therefore, according to each embodiment, it is possible to provide an imaging device that performs pupil-division focus detection, a method for controlling the imaging device, a program, and a storage medium that can easily secure a sufficient amount of light.

  As mentioned above, although preferable embodiment of this invention was described, this invention is not limited to these embodiment, A various deformation | transformation and change are possible within the range of the summary.

100 imaging device 107 imaging device 121 CPU (focus detection means)

Claims (17)

An image sensor including a first pixel divided by a first area ratio and a second pixel divided by a second area ratio different from the first area ratio;
Obtained from the output signal of the imaging element, by using a plurality of pupil division signals corresponding to the light beams passing through different divided pupil areas of the photographing optical system, have a focus detection means for performing focus detection,
The focus detection unit passes through an output signal of one divided pixel included in the first pixel and a pupil partial region overlapping with the one divided pixel among the divided pixels included in the second pixel. An image pickup apparatus that performs focus detection using a difference signal between an output signal of a divided pixel that receives a light beam and has a light receiving area different from that of the one divided pixel as the pupil divided signal .   The imaging device according to claim 1, wherein the first pixel and the second pixel are arranged adjacent to each other.   The imaging device according to claim 1, wherein the first pixel and the second pixel are arranged along a circumferential direction with a center of an imaging surface of the imaging element as a reference. .   The first pixel and the second pixel are arranged along a second direction orthogonal to the first direction in a region located in the first direction with reference to the center of the imaging surface of the imaging element. The imaging apparatus according to any one of claims 1 to 3, wherein the imaging apparatus is configured. The number of pupil division signals that can be acquired using the output signal of the first pixel and the output signal of the second pixel is greater than the number of divisions of the first pixel and the division of the second pixel The imaging apparatus according to claim 1, wherein the imaging apparatus has more than the number. The imaging device further includes a third pixel divided by a third area ratio,
The first pixel includes a first divided pixel and a second divided pixel in which the first area ratio is 1: 3,
The second pixel includes a third divided pixel and a fourth divided pixel in which the second area ratio is 1: 1,
The third pixel, the third area ratio 3: according to 1 having a fifth divided pixels and sixth divided pixels is, any one of claims 1 to 5, characterized in that Imaging device. The focus detection means includes
The output signal of the first divided pixel is a first pupil division signal,
The difference between the output signal of the third divided pixel and the output signal of the first divided pixel, or the difference between the output signal of the second divided pixel and the output signal of the fourth divided pixel is the second difference. The pupil division signal of
The difference between the output signal of the fourth divided pixel and the output signal of the sixth divided pixel, or the difference between the output signal of the fifth divided pixel and the output signal of the third divided pixel is the third difference. The pupil division signal of
The output signal of the sixth divided pixel is configured to be acquired as a fourth pupil division signal,
The focus detection is performed based on at least two of the first pupil division signal, the second pupil division signal, the third pupil division signal, and the fourth pupil division signal. The imaging device according to claim 6 . The focus detection unit is configured to select the first pupil division signal, the second pupil division signal, the third pupil division signal, and the fourth pupil division selected according to an aperture value or a pupil position. The imaging apparatus according to claim 7 , wherein the focus detection is performed based on at least two of the signals. The focus detection means includes
When the aperture value is less than or equal to a predetermined aperture value, the focus detection is performed based on the first pupil division signal and the fourth pupil division signal,
The imaging according to claim 8 , wherein when the aperture value is larger than the predetermined aperture value, the focus detection is performed based on the second pupil division signal and the third pupil division signal. apparatus. The focus detection means includes
When the pupil position is closer to the image sensor than a predetermined pupil position, the focus detection is performed based on the first pupil division signal and the third pupil division signal,
Claim 8 wherein the pupil position may farther from the imaging device than the predetermined pupil position, performs the focus detection based on the second pupil division signal and the fourth pupil division signal, it is characterized by Or the imaging device of 9 . The first pixel includes a first divided pixel, a second divided pixel, and a third divided pixel, wherein the first area ratio is 1: 3: 1.
The second pixel includes a fourth divided pixel, a fifth divided pixel, and a sixth divided pixel in which the second area ratio is 2: 1: 2. The imaging device according to any one of 1 to 5 . The focus detection means includes
The output signal of the first divided pixel is a first pupil division signal,
The difference between the output signal of the fourth divided pixel and the output signal of the first divided pixel is a second pupil divided signal,
The output signal of the fifth divided pixel is a third pupil division signal,
The difference between the output signal of the sixth divided pixel and the output signal of the third divided pixel is a fourth pupil divided signal,
The output signal of the third divided pixel is configured to be acquired as a fifth pupil divided signal,
The focus based on at least two of the first pupil division signal, the second pupil division signal, the third pupil division signal, the fourth pupil division signal, and the fifth pupil division signal The imaging apparatus according to claim 11 , wherein detection is performed. The focus detection unit is selected according to an aperture value or a pupil position, and the first pupil division signal, the second pupil division signal, the third pupil division signal, the fourth pupil division signal, The imaging apparatus according to claim 12 , wherein the focus detection is performed based on at least two of the fifth pupil division signals. The imaging device includes a plurality of focus detection pixels including the first pixel and the second pixel, and a plurality of imaging pixels.
The plurality of focus detection pixels receive light beams passing through different pupil regions of the photographing optical system and output image signals,
Wherein the plurality of imaging pixels, the outputs an image signal by receiving the light beam passing through the same pupil area of the photographing optical system, that imaging apparatus according to any one of claims 1 to 13, characterized in . First pixels divided by the first area ratio, and is obtained from the output signal of the imaging element comprising a second pixel that are divided by a different second area ratio to the first area ratio, A control method for an imaging apparatus that performs focus detection using a plurality of pupil division signals corresponding to light beams that have passed through different division pupil regions of an imaging optical system ,
Receiving an output signal of one divided pixel included in the first pixel and a light flux that has passed through a pupil partial region overlapping with the one divided pixel among the divided pixels included in the second pixel; and Calculating a difference between one divided pixel and an output signal of a divided pixel having a different light receiving area ;
And a step of performing the focus detection using the difference as the pupil division signal . First pixels divided by the first area ratio, and is obtained from the output signal of the imaging element comprising a second pixel that are divided by a different second area ratio to the first area ratio, A program for performing focus detection using a plurality of pupil division signals corresponding to light beams that have passed through different division pupil regions of the photographing optical system ,
Receiving an output signal of one divided pixel included in the first pixel and a light flux that has passed through a pupil partial region overlapping with the one divided pixel among the divided pixels included in the second pixel; and Calculating a difference between one divided pixel and an output signal of a divided pixel having a different light receiving area ;
A program configured to cause a computer to execute the focus detection using the difference as the pupil division signal . A storage medium storing the program according to claim 16 .