Imaging device and readout control method

Abstract

To provide an imaging device etc. that can realize highly accurate subject tracking when imaging at a normal frame rate, and can continue AF processing while suppressing power consumption when imaging at a frame rate faster than the normal frame rate. [Solution] The imaging device includes an imaging element in which pixels each including a first photoelectric conversion unit and a second photoelectric conversion unit are arranged, and a read control unit that performs a first read control when a first mode is selected, in which the charges of the first photoelectric conversion unit and the second photoelectric conversion unit are separately AD converted to generate a pixel signal, and when a second mode in which a high frame rate is set is selected, performs a second read control when a first pixel is discretely set, in which the charges of the first photoelectric conversion unit and the second photoelectric conversion unit are separately AD converted to generate a first pixel signal, and when a second pixel that is not the first pixel is discretely set, performs a second read control when the charges of the first photoelectric conversion unit and the second photoelectric conversion unit are added together and then AD converted to generate a second pixel signal.

Description

[Technical field]

[0001] The present invention relates to an imaging apparatus and a readout control method for reading out pixel signals from an imaging element. [Background technology]

[0002] There is known an imaging device that performs autofocus control using a phase difference signal obtained on the image plane of an imaging element. An imaging element capable of outputting such a phase difference signal includes two photoelectric conversion units, each of which has a pupil divided for one microlens. If the pixel signals output from the two photoelectric conversion units are used as separate phase difference signals, they can be used to calculate the amount of blur in autofocus (AF). If the pixel signals output from the two photoelectric conversion units are added to generate an image signal, the image signals of effective pixels can be collected to generate a frame image as a subject image (see, for example, Patent Document 1). Recent imaging devices employ such imaging elements to perform high-precision AF even during video shooting, and can maintain a focused state even for a moving subject. In addition, the total number of pixels of the imaging element is gradually increasing, and the focusing precision is improving accordingly. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-134154 A Summary of the Invention [Problem to be solved by the invention]

[0004] High frame mode (slow motion mode) is gaining popularity, which allows you to enjoy smooth subject movement at a slower rate than in reality by capturing images at a faster frame rate than normal and playing them back at the normal frame rate. In high frame mode, pixel signals are read out at a faster frame rate than normal, consuming a lot of power and sometimes causing the pixel signal readout process to be unable to keep up. When the pixel signal readout process is unable to keep up, the AF process breaks down and the subject cannot be kept in focus.

[0005] The present invention has been made to solve such problems, and provides an imaging device etc. that can achieve highly accurate subject tracking when imaging at a normal frame rate, and can continue AF processing while reducing power consumption when imaging at a frame rate faster than the normal frame rate. [Means for solving the problem]

[0006] An imaging device in a first aspect of the present invention includes an imaging element in which a plurality of pixels are two-dimensionally arranged, each including a first photoelectric conversion unit that receives a light beam passing through a first partial region of an imaging optical system and a second photoelectric conversion unit that receives a light beam passing through a second partial region different from the first partial region, and a readout control unit that performs a first readout control when a first mode is selected, in which the charges of the first photoelectric conversion unit and the second photoelectric conversion unit are separately AD converted to generate a pixel signal, and when a second mode in which a frame rate faster than the frame rate set in the first mode is selected, performs a second readout control in which, in first pixels that are discretely set among the pixels, the charges of the first photoelectric conversion unit and the second photoelectric conversion unit are separately AD converted to generate a first pixel signal, and in a second pixel that is not the first pixel among the pixels, the charges of the first photoelectric conversion unit and the second photoelectric conversion unit are added together and then AD converted to generate a second pixel signal.

[0007] In addition, a readout control method in a second aspect of the present invention causes a computer to execute the following steps: reading out pixel signals from an imaging element in which a plurality of pixels are two-dimensionally arranged, the pixels including a first photoelectric conversion unit that receives a light beam passing through a first partial region of an imaging optical system and a second photoelectric conversion unit that receives a light beam passing through a second partial region different from the first partial region; a receiving step of receiving a selection from a first mode and a second mode in which a frame rate faster than a frame rate set in the first mode is set; and a readout control step of performing a first readout control in which, when the first mode is selected, the charges of the first photoelectric conversion unit and the second photoelectric conversion unit are separately AD converted to generate a pixel signal, and, when the second mode is selected, a second readout control in which, in a first pixel that is discretely set among the pixels, the charges of the first photoelectric conversion unit and the second photoelectric conversion unit are separately AD converted to generate a first pixel signal, and, in a second pixel that is not the first pixel among the pixels, the charges of the first photoelectric conversion unit and the second photoelectric conversion unit are added together and then AD converted to generate a second pixel signal. Effect of the Invention

[0008] The present invention makes it possible to provide an imaging device etc. that can achieve highly accurate subject tracking when imaging at a normal frame rate, and can continue AF processing while reducing power consumption when imaging at a frame rate faster than the normal frame rate. [Brief description of the drawings]

[0009] [Figure 1] 1 is a diagram showing the appearance of an imaging device according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a diagram illustrating a main hardware configuration of the imaging apparatus. [Diagram 3] FIG. 2 is a diagram illustrating a pixel arrangement of an imaging element. [Figure 4] FIG. 2 is a diagram illustrating a configuration of a pixel. [Diagram 5] 5A and 5B are diagrams illustrating pixel signal readout control by a readout control unit. [Figure 6] FIG. 2 is a diagram illustrating the setting of a first pixel and a second pixel. [Figure 7] FIG. 13 is a diagram illustrating a window width for generating a phase waveform. [Figure 8] FIG. 4 is a flowchart showing a processing procedure of a system control unit. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The present invention will be described below through embodiments of the invention, but the invention according to the claims is not limited to the following embodiments. In addition, not all of the configurations described in the embodiments are necessarily essential as means for solving the problems. In addition, in each figure, when there are multiple structures having the same or similar configurations, in order to avoid complication, some of the structures may be given reference symbols and the same reference symbols may be omitted for the others.

[0011] FIG. 1 is a diagram showing the appearance of an imaging device 100 according to this embodiment. In particular, FIG. 1(A) is a diagram mainly showing the first surface side of the imaging device 100, and FIG. 1(B) is a diagram mainly showing the second surface side opposite to the first surface side. The imaging device 100 according to this embodiment is a so-called smartphone, in other words, a smartphone that also functions as an imaging device. In the following, the imaging function related to the present invention among the functions of the smartphone will be described, and the description of other functions as a smartphone, such as the use of image data generated by imaging, will be omitted. Note that in this embodiment, the imaging device 100 will be described using a smartphone as an example, but it may of course be an imaging device as a standalone camera, or may be a device incorporated in a tablet terminal or the like and equipped with an imaging function.

[0012] The imaging device 100 includes a first camera unit 110 and a second camera unit 120 arranged in the same direction on the first surface side. The first camera unit 110 is a camera unit for generating a wide-angle image. The second camera unit 120 is a camera unit for generating a telephoto image. When a user wants to obtain a wide-angle image, the user specifies the first camera unit to capture an image, and when a user wants to obtain a telephoto image, the user specifies the second camera unit to capture an image. In the figure, the first camera unit 110 and the second camera unit 120 are arranged parallel to the long side of the imaging device 100, but the arrangement of the two camera units is not limited to this, and they may be arranged, for example, along a straight line obliquely intersecting the long side. In addition, the arrangement of the first camera unit 110 and the second camera unit 120 may be reversed from the positions shown in the figure.

[0013] The imaging device 100 has a display 130 on the second surface side. The display 130 is a display device that employs, for example, an organic EL (Electro Luminescence) panel, and displays a real-time image of a subject before imaging (live view display), displays a real-time image during video imaging (rec view display), and displays an image after imaging. Note that a camera unit for self-portraits, independent of the first camera unit 110 and the second camera unit 120, may be provided on the second surface side.

[0014] A touch panel 162 is provided superimposed on the display 130. The user can give the imaging device 100 an instruction to capture a still image by tapping a shutter button displayed on the display 130, and can give the imaging device 100 an instruction to start and stop recording a video by tapping a video capture button. In addition, the user can tap any point on the subject image displayed by live view or rec view to specify a certain area including that point as a focus area. In addition, the user can switch between the first camera unit 110 and the second camera unit 120 or select a displayed menu item by a contact operation such as tapping.

[0015] 2 is a diagram showing the main hardware configuration of the imaging device 100. In addition to the above-mentioned first camera unit 110, second camera unit 120, and display 130, the imaging device 100 is made up of a system control unit 150 that controls these units, and peripheral elements that cooperate with the system control unit 150.

[0016] The first camera unit 110 is a camera unit for generating a wide-angle image as described above, and mainly includes a first optical system 111, a first driving mechanism 112, a first image sensor 113, and a first analog front end (AFE) 114. The first optical system 111 is an optical system for forming an image of an incident subject light flux on an image sensor surface of the first image sensor 113. Although the first optical system 111 is shown as a single lens in the figure, it is generally composed of multiple lenses, at least a part of which is a focus lens that can advance and retreat along the optical axis direction. The first driving mechanism 112 is a driving mechanism for moving the focus lens of the first optical system 111 along the optical axis direction, and includes an actuator that operates according to an instruction from the system control unit 150.

[0017] The first imaging element 113 is, for example, a CMOS image sensor. The first imaging element 113 will be described in detail later. The first imaging element 113 passes an output signal to the first AFE 114 under the control of the system control unit 150 and the first AFE 114. The first AFE 114 adjusts the read timing of the output signal and adjusts the level according to a specified gain, in addition to performing AD conversion control, which will be described later. The pixel signal adjusted by the first AFE 114 is passed to the work memory 151.

[0018] The second camera unit 120 is a camera unit for generating a telephoto image as described above, and mainly includes a second optical system 121, a second driving mechanism 122, a second image sensor 123, and a second analog front end (AFE) 124. The second optical system 121 is an optical system for forming an image of an incident subject light flux on an image sensor surface of the second image sensor 123. Although shown as a single lens in the figure, the second optical system 121 is generally composed of multiple lenses, similar to the first optical system 111, at least a part of which is a focus lens that can be advanced and retreated along the optical axis direction. The second driving mechanism 122 is a driving mechanism for moving the focus lens of the second optical system 121 along the optical axis direction, and includes an actuator that operates according to an instruction from the system control unit 150.

[0019] The second imaging element 123 is, for example, a CMOS image sensor. The second imaging element 123 will be described later in detail together with the first imaging element 113. The second imaging element 123 passes an output signal to the second AFE 114 under the control of the system control unit 150 and the second AFE 124. The second AFE 124 performs AD conversion control, which will be described later, and also adjusts the read timing of the output signal and adjusts the level according to a specified gain. The pixel signal adjusted by the second AFE 124 is passed to the work memory 151. In this embodiment, both the first optical system 111 and the second optical system 121 are assumed to be single-focus optical systems with fixed focal lengths, but at least one of them may be a variable-focus optical system (zoom lens) with a variable focal length.

[0020] The system control unit 150 is a processor (CPU: Central Processing Unit) that directly or indirectly controls each element constituting the imaging device 100. The system control unit 150 plays various roles as a function control unit according to the control method to be executed, for example, it functions as a detection unit that performs phase difference detection for a subject image when executing autofocus control of the first camera unit 110 and the second camera unit 120, and it functions as a display control unit when displaying a captured image on the display 130. Particularly in this embodiment, it functions as a read control unit that reads out output signals from the first imaging element 113 and the second imaging element 123 to generate pixel signals. Specific control of the read control unit will be described later.

[0021] The imaging device 100 mainly includes a work memory 151, an image processing unit 152, an operation unit 160, a recording unit 170, and a communication interface 180 as peripheral elements that cooperate with the system control unit 150. The work memory 151 is a volatile high-speed memory, and is configured, for example, by a static random access memory (SRAM). The work memory 151 receives pixel signals that are sequentially converted from the first AFE 114 and the second AFE 124, and stores them as frame data for one frame. The work memory 151 also extracts a specific pixel signal as a phase difference signal, and generates and stores phase waveform data used for AF bokeh amount calculation. The work memory 151 passes the frame data to the image processing unit 153, and passes the phase waveform data to the system control unit 150. The work memory 151 is also appropriately used as a temporary storage area in the processing stage in which the image processing unit 153 performs image processing and the processing stage in which the system control unit 150 performs focusing processing.

[0022] The image processing unit 153 is configured, for example, by an ASIC (Application Specific Integrated Circuit) that performs image processing exclusively, and performs various image processing such as interpolation processing on the received frame data to generate image data in a predetermined format. If the generated image data is for recording, it is recorded in the recording unit 170, and if it is for display, it is displayed on the display 130.

[0023] The operation unit 160 is an input device including a touch panel 162, and is a member that is operated when the user gives instructions to the imaging device 100. When the imaging device 100 accepts voice input, the operation unit 160 may also include a microphone. The recording unit 170 is a non-volatile memory, and is configured, for example, by an SSD (Solid State Drive). In addition to recording image data generated by imaging, the recording unit 170 holds constants, variables, setting values, control programs, and the like required during operation of the imaging device 100. The communication interface 180 may include a communication unit for a 5G line or a wireless LAN. The communication interface 180 is used when transferring the generated image data to an external device, etc.

[0024] Next, the structure of the imaging element and the read control of the pixel signal will be described. In this embodiment, the first imaging element 113 and the second imaging element 123 adopt imaging elements having the same structure, and the first AFE 114 and the second AFE 124 execute the same read control for these imaging elements. Therefore, here, assuming a case where the first camera unit 110 captures a moving image, the structure of the first imaging element 113 (hereinafter simply referred to as "imaging element 113") and the read control by the system control unit 150 (read control unit) via the first AFE 114 (hereinafter simply referred to as "AFE 114") will be described.

[0025] 3 is a diagram illustrating a pixel array of the image sensor 113. In the image sensor 113, each pixel 200 includes a first photoelectric conversion unit 201 and a second photoelectric conversion unit 202, and a plurality of such pixels 200 are two-dimensionally arranged to form a pixel plane. The first photoelectric conversion unit 201 and the second photoelectric conversion unit 202 each form a substantially rectangular shape obtained by substantially dividing a square pixel region into two equal parts. With respect to the center of the pixel 200, the first photoelectric conversion unit 201 is offset in a first direction (to the left in the figure), and the second photoelectric conversion unit 202 is offset in a second direction opposite to the first direction (to the right in the figure). In one possible embodiment, each of the pixels 200 may include more than two photoelectric conversion units, for example, four, and it should be understood that the four photoelectric conversion units may be arranged in a 2×2 array, for example.

[0026] FIG. 4 is a diagram for explaining the configuration of the pixel 200, and is a diagram that diagrammatically illustrates a cross section of the first optical system 111 (hereinafter simply referred to as “optical system 111”), a cross section of the pixel 200, and a part of the circuit of the AFE 114.

[0027] The first photoelectric conversion unit 201 receives a light beam passing through a first partial region PA1 of the optical system 111, which is an imaging optical system. The second photoelectric conversion unit 202 receives a light beam passing through a second partial region PA2 different from the first partial region PA1 of the optical system 111. The first partial region PA1 and the second partial region PA2 may have an overlapping region. Both light beams pass through a microlens 211 and a color filter 212 arranged above the pixel to reach the respective photoelectric conversion unit.

[0028] The charge accumulated in the first photoelectric conversion unit 201 is converted into a digital signal by the AD converter 230 when the first switch 221 is closed, and is output as a pixel signal. The charge accumulated in the second photoelectric conversion unit 202 is converted into a digital signal by the AD converter 230 when the second switch 222 is closed, and is output as a pixel signal.

[0029] 5 is a diagram illustrating the readout control of pixel signals by the readout control unit. The readout control unit can perform either individual readout control or batch readout control on the pixels 200 in a charge accumulation state to generate pixel signals.

[0030] FIG. 5(A) is a diagram for explaining individual readout control. In the individual readout control, first, as shown in the upper diagram of FIG. 5(A), the readout control unit closes the first switch 221 and leaves the second switch 222 open, so that only the charge accumulated in the first photoelectric conversion unit 201 is AD converted by the AD converter 230, and a pixel signal A is output. At this time, there is no change in the charge accumulated in the second photoelectric conversion unit 202. Next, as shown in the lower diagram of FIG. 5(A), the readout control unit closes the second switch 222 and opens the first switch 221, so that only the charge accumulated in the second photoelectric conversion unit 202 is AD converted by the AD converter 230, and a pixel signal B is output. In this way, by repeating the AD conversion twice, the pixel signal A corresponding to the charge of the first photoelectric conversion unit 201 and the pixel signal B corresponding to the charge of the second photoelectric conversion unit 202 can be output sequentially. Since pixel signal A and pixel signal B are both signals generated from the same pixel, they are collectively referred to as a first pixel signal here. Note that the order in which pixel signal A and pixel signal B are generated may be reversed.

[0031] 5B is a diagram for explaining the batch readout control. In the batch readout control, the readout control unit closes both the first switch 221 and the second switch 222, adds the charge accumulated in the first photoelectric conversion unit 201 and the charge accumulated in the second photoelectric conversion unit 202, performs AD conversion by the AD converter 230, and outputs a second pixel signal. In this way, a second pixel signal corresponding to the charge obtained by adding up the charge of the first photoelectric conversion unit 201 and the charge of the second photoelectric conversion unit 202 can be output by a single AD conversion.

[0032] When a normal imaging mode with a normal frame rate (e.g., 30 fps or 60 fps) is selected, the readout control unit executes a first readout control that applies individual readout control to all pixels. In this case, the pixel value of the pixel signal A, which is the first pixel signal, is added to the pixel value of the pixel in the frame data. In addition, by separately collecting the pixel signals A and B of a pixel group corresponding to a specific subject image designated by a user or selected by an automatic algorithm, phase waveform data for the specific subject image can be generated. In other words, if the first pixel signals are generated from all pixels, dense phase waveform data can be generated for any subject, and a highly accurate focus state can be maintained even for a moving subject during the imaging period.

[0033] On the other hand, when the first readout control is executed during imaging at a frame rate (for example, 120 fps or 240 fps) faster than the normal frame rate, two AD conversions are required for each of all pixels, and this significantly increases power consumption. The increase in power consumption not only shortens the usage time of the imaging device, but may also cause the operation of the imaging device to become unstable due to the heat generated. In addition, the processing time required for two AD conversions and the processing time for processing the enormous amount of generated first pixel signals may not fit within the frame rate period. In other words, the readout process and data processing may not be able to keep up with the high frame rate. In such a state, not only may it be impossible to maintain the focus state of the subject, but it may also be impossible to generate a frame image.

[0034] Therefore, in this embodiment, when an imaging mode in which a high frame rate is set is selected, a second read control that mixes individual read control and batch read control is executed. An example of an imaging mode in which a high frame rate is set is a high frame mode (slow motion mode) in which images of a subject moving smoothly but at a slower speed than in reality can be enjoyed by playing back the images at a normal frame rate.

[0035] When the second readout control is performed, a setting is performed in advance for all effective pixels of the image sensor 111 to divide them into first pixels to which the individual readout control is applied and second pixels to which the collective readout control is applied. Fig. 6 is a diagram for explaining the setting of the first and second pixels when the second readout control is performed. In the figure, the pixels surrounded by a thick frame are set as the first pixels 200a, and the other pixels are set as the second pixels 200b.

[0036] In the illustrated example, the first pixels 200a are periodically set at a ratio of one for every 5 pixels vertical by 5 pixels horizontal. In this manner, the first pixels 200a are discretely arranged surrounded by the second pixels 200b, so that the number of first pixels 200a that perform individual readout control can be significantly reduced. By significantly reducing the number of first pixels 200a, the overall power consumption can be reduced. In addition, the amount of pixel signals generated can be reduced, so that the time required for calculation processing can be shortened, and AF processing and generation of frame images can be appropriately continued even at a high frame rate.

[0037] However, since the phase waveform data for performing AF processing can only be obtained from the first pixels 200a that are discretely arranged, it is necessary to consider the balance with the decrease in focusing accuracy. That is, the ratio of the first pixels 200a to the second pixels 200b is determined by considering the balance between the advantages of power saving and high-speed processing and the disadvantage of the decrease in focusing accuracy. For example, when the user can select multiple frame rates, an adjustment can be made such that the ratio of the first pixels 200a to the second pixels 200b is reduced for a faster frame rate. The first pixels 200a that are discretely arranged for AF processing may be arranged in a number of ways. For example, they may be arranged evenly at a certain ratio, i.e., the first pixels 200a are distributed over all pixels at a certain ratio. In this manner, the overall focusing performance can be kept uniform, or a large number of first pixels 200a are arranged in the center of the image, and a few first pixels 200a are arranged on the edge. It should be understood that such a center-priority arrangement method is arranged for a portrait mode or a mode that emphasizes a specific part, and provides better focusing performance in the center of the image.

[0038] In addition, in order to improve the focusing accuracy even with the limited number of first pixels 200a, the window width for generating the phase waveform may be adjusted. FIG. 7 is a diagram for explaining the window width for generating the phase waveform.

[0039] FIG. 7A shows a first window width that is set when performing a first readout control in which individual readout control is applied to all pixels 200. The first window width is W 1 The phase difference detection unit 100 detects the phase difference of the subject image and performs focusing when the first readout control is performed. The phase difference detection unit 100 detects the phase difference of the subject image and performs focusing when the first readout control is performed.

[0040] FIG. 7B shows the second window width set when performing the second read control in which the individual read control and the batch read control are mixed. The second window width is W 1 More W than pixels 2 The second window width is set to one pixel, and when the second readout control is performed, the detection unit generates a phase waveform using pixel signal A and pixel signal B generated from the first pixel 200a that is the target of individual readout control among the pixels 200 included in this second window width, and performs phase difference detection for the subject image.

[0041] That is, when the second readout control is performed, if the first window width is set to the same value as that when the first readout control is performed, the phase waveform that can be generated becomes short, but by setting a second window width larger than the first window width and lengthening the length of the phase waveform to be generated, the decrease in accuracy of phase difference detection is compensated for. However, if the window width is increased, the possibility of capturing multiple subjects across each other increases accordingly, making perspective conflict more likely to occur. Therefore, it is preferable to appropriately set the enlargement of the window width according to the ratio of the first pixel 200a to the second pixel 200b.

[0042] Next, a process procedure of the system control unit 150 in a series of moving image shooting processes will be described with reference to FIG 8. The process procedure of the system control unit 150 will be described with reference to FIG 8.

[0043] In step S101, the system control unit 150 receives from the user a selection between a first mode in which a normal frame rate is set and a second mode in which a frame rate faster than the normal frame rate is set. The system control unit 150 switches to the selected imaging mode, and in step S102 waits for an instruction to start imaging from the user. When the instruction to start imaging is received, the system control unit 150 proceeds to step S103, where it checks the current imaging mode, and if it is the first mode (normal frame rate), it proceeds to step S104, and if it is the second mode (higher frame rate), it proceeds to step S108.

[0044] When the process proceeds from step S103 to step S104, the system control unit 150, as a readout control unit, executes a first readout control. In the following step S105, the system control unit 150, as a detection unit, generates a phase waveform from a first window width set for a pixel group corresponding to a specific subject image, performs phase difference detection, and executes AF processing. In the following step S106, the system control unit 150 generates frame data for one frame according to the set normal frame rate. In step S107, the system control unit 150 checks whether an instruction to stop image capture has been received from the user. If an instruction to stop image capture has not been received, the process returns to step S104 to continue video capture, and if an instruction to stop image capture has been received, the system control unit 150 performs a set format process on the frame data accumulated up to that point to generate a video file, and ends the series of processes.

[0045] When the process proceeds from step S103 to step S108, the system control unit 150, as a readout control unit, executes the second readout control. In the following step S109, the system control unit 150, as a detection unit, generates a phase waveform from the second window width set for the pixel group corresponding to the specific subject image, performs phase difference detection, and executes AF processing. In the following step S110, the system control unit 150 generates frame data for one frame according to the set high-speed frame rate. In step S111, the system control unit 150 checks whether an instruction to stop image capture has been received from the user. If an instruction to stop image capture has not been received, the process returns to step S108 to continue video capture, and if an instruction to stop image capture has been received, the system control unit 150 performs the set format processing on the frame data accumulated up to that point to generate a video file, and ends the series of processes.

[0046] In the embodiment described above, a case where a moving image is captured is assumed, but the same focus control can be executed even when a still image is captured. That is, when a still image is captured every time the shutter button is tapped, or when an imaging mode for capturing images continuously at a low speed is selected, a first readout control that applies individual readout control to all pixels 200 can be applied, and when an imaging mode for capturing images continuously at a high speed is selected, a second readout control that mixes individual readout control and batch readout control can be applied. In one possible embodiment, two or more imaging modes may be provided based on different imaging frame rates or continuous shooting speeds, each mode corresponding to different focus accuracy, for example, the higher the frame rate / faster the continuous shooting speed, the fewer pixels are used for focusing, thus providing a flexible balance between power consumption and performance. [Explanation of symbols]

[0047] 100...imaging device, 110...first camera unit, 111...first optical system (optical system), 112...first driving mechanism (driving mechanism), 113...first imaging element (imaging element), 114...first analog front end (AFE), 120...second camera unit, 121...second optical system, 122...second driving mechanism, 123...second imaging element, 124...second analog front end, 130...display, 150...system System control unit, 151...work memory, 152...image processing unit, 160...operation unit, 162...touch panel, 170...recording unit, 180...communication interface, 200...pixel, 200a...first pixel, 200b...second pixel, 201...first photoelectric conversion unit, 202...second photoelectric conversion unit, 210...microlens, 212...color filter, 221...first switch, 222...second switch, 230...AD converter

Claims

1. an image sensor in which a plurality of pixels are two-dimensionally arranged, the pixels including at least a first photoelectric conversion unit that receives a light beam passing through a first partial region of an image forming optical system and a second photoelectric conversion unit that receives a light beam passing through a second partial region different from the first partial region; a readout control unit that performs a first readout control in which, when a first mode is selected, charges of the first photoelectric conversion unit and the second photoelectric conversion unit are separately AD converted to generate a pixel signal, and when a second mode in which a frame rate faster than a frame rate set in the first mode is selected, performs a second readout control in which, in first pixels that are discretely set among the pixels, charges of the first photoelectric conversion unit and the second photoelectric conversion unit are separately AD converted to generate a first pixel signal, and, in a second pixel that is not the first pixel among the pixels, charges of the first photoelectric conversion unit and the second photoelectric conversion unit are added together and then AD converted to generate a second pixel signal; An imaging device comprising:

2. The imaging device according to claim 1 , further comprising a detection unit that performs phase difference detection autofocus using pixel signals obtained by separately AD-converting the charges of the first photoelectric conversion unit and the second photoelectric conversion unit.

3. The imaging device according to claim 2 , wherein the detection section, when the readout control section performs the second readout control, sets a window width for generating a phase waveform to be larger than that when the readout control section performs the first readout control.

4. A read control method, comprising: reading out pixel signals from an image sensor in which a plurality of pixels are two-dimensionally arranged, the pixels including a first photoelectric conversion unit that receives a light beam passing through a first partial region of an imaging optical system and a second photoelectric conversion unit that receives a light beam passing through a second partial region different from the first partial region; determining one mode from a first mode and a second mode in which a frame rate higher than a frame rate set in the first mode is set; a step of performing a first readout control in which, in the first mode, charges of the first photoelectric conversion unit and the second photoelectric conversion unit are separately AD converted to generate a pixel signal, and, in the second mode, performing a second readout control in which, in a first pixel that is discretely set among the pixels, charges of the first photoelectric conversion unit and the second photoelectric conversion unit are separately AD converted to generate a first pixel signal, and, in a second pixel that is not the first pixel among the pixels, charges of the first photoelectric conversion unit and the second photoelectric conversion unit are added together and then AD converted to generate a second pixel signal; Readout control method.

5. performing phase difference detection autofocus using pixel signals obtained by separately AD-converting the charges of the first photoelectric conversion unit and the second photoelectric conversion unit; The read control method according to claim 4.

Images