JP2013055553A - Imaging apparatus and control method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an imaging apparatus which prevents distortion of a captured image by an imaging element of an XY address system and can suppress deterioration of the captured image due to leakage of light into a pixel.SOLUTION: Transfer registers in whole rows and reset transistors in whole rows are turned on, a photodiode and FD are reset, and exposure of the photodiode is started (timing t1). After lapse of prescribed exposure time, the transfer transistors in the whole rows are turned on, and signal charges of the photodiodes of whole pixels are transferred to FD. Thus, exposure is terminated (timing t2). A close operation of a diaphragm is performed and a difference between an upper side and a lower side of light leakage is reduced (timing t8 to t9). A voltage corresponding to the signal charge transferred from the photodiode is sequentially read for each row from FD (timing t5 to t6).

Description

  The present invention relates to an image pickup apparatus that picks up an image using an image pickup element and a control method thereof, and more particularly, to an image pickup apparatus that picks up an image using an image pickup element such as a CMOS image sensor that reads out each pixel signal by an XY address method and its control. Regarding the method.

  2. Description of the Related Art In recent years, imaging apparatuses that can capture an image using an image sensor and store the captured image as digital data, such as a digital still camera and a digital video camera, are widely used. A CCD (Charge Coupled Device) type image sensor has been most commonly used as an image pickup element used in such an image pickup apparatus. In recent years, CMOS (Complementary Metal Oxide Semiconductor) type image sensors have been attracting attention as the number of pixels of image pickup devices has further increased. The CMOS type image sensor has features such that the pixel signal can be randomly accessed, and that the pixel signal is read out at a higher speed than the CCD type image sensor, and has high sensitivity and low power consumption.

  By the way, when a mechanical shutter is used to control the exposure time in the imaging apparatus, variations in the exposure time may occur due to positional accuracy errors or shutter blade operation accuracy errors that occur during assembly. . In particular, at the time of high-speed shutter, the ratio of error to the exposure time becomes large. In contrast, many image sensors have an electronic shutter function.

  The electronic shutter function starts exposure by resetting the pixels of the image sensor, and ends the exposure by reading signals of the pixels of the image sensor. As described above, since the start and end of exposure are controlled only by the function of the image sensor, it is possible to realize accurate exposure time control from a low-speed shutter to a high-speed shutter.

  Unlike the CCD type, the electronic shutter function of the CMOS type image sensor is a so-called rolling shutter (also called a focal plane shutter) that reads a signal by sequentially scanning a plurality of pixels arranged two-dimensionally for each pixel row. . Therefore, there is a problem that the exposure period is shifted for each row. For example, as shown in FIG. 9B of Patent Document 1, when a linear subject S is moving in the left-right direction in the up-down direction, the subject S is tilted in the still image obtained by capturing the subject S. It will be reflected.

  In order to solve the above problem, there is also a CMOS type image sensor in which the electronic shutter is simultaneously turned off for all rows so that the exposure periods are matched (see, for example, FIG. 11 of Patent Document 1). In this CMOS image sensor, the photodiodes are simultaneously reset at a certain point in time, and the charges of the photodiodes are simultaneously transferred to the floating diffusion (FD) after a predetermined exposure time. Then, the FD signal is sequentially output line by line. In this way, as shown in FIG. 11B of Patent Document 1, even when the linear subject S moves in the vertical direction, the still image obtained by capturing the subject S does not This makes it possible to take a picture in an upright state without tilting.

  However, in the pixel of the CMOS type image sensor that implements FIG. 11 of Patent Document 1 (FIG. 10 of Patent Document 1), it is difficult to completely shield light other than the photodiode. Therefore, before the FD signal is output, light leaks into the FD, and the amount of the light differs between the first output row and the later output row. For this reason, there is a problem in that a vertical difference in light leakage occurs and the captured image is deteriorated.

  In addition, a technique has been proposed in which the readout direction of the row unit of the CMOS image sensor and the light shielding direction of the mechanical shutter are the same, and the reset of the photodiode and the transfer to the FD are controlled so as to match the light shielding operation of the mechanical shutter. (For example, refer to Patent Document 2). In this way, as shown in FIG. 3 of Patent Document 2, the time from the transfer to the FD to the light shielding by the mechanical shutter can be made equal for all rows, so that the vertical difference in light leakage is eliminated.

JP 2006-191236 A JP-A-2005-176105

  However, as can be seen in FIG. 3 of Patent Document 2, the resetting of the photodiode and the transfer to the FD are not performed at the same time for all rows, so that the moving subject appears in an inclined state. As described above, in the CMOS type image sensor, in order to solve the problem that the moving subject appears in a tilted state, when the resetting of the photodiode and the transfer to the FD are performed simultaneously on all rows, the light leakage to the FD is increased or decreased. There remains a problem that a difference occurs and the captured image is deteriorated.

  In addition, when the resetting of the photodiode and the transfer to the FD are controlled so as to match the light shielding operation of the mechanical shutter in order to eliminate the vertical difference of the light leakage, the moving subject appears in an inclined state. The problem remains.

  The present invention has been made in view of the above problems, and prevents distortion of a captured image by an XY addressing-type image sensor and suppresses deterioration of a captured image due to light leakage into a pixel. It is an object of the present invention to provide an imaging apparatus capable of performing the above and a control method thereof.

  In order to achieve the above object, an imaging apparatus according to the present invention includes a photoelectric conversion unit that photoelectrically converts incident light, a storage unit that accumulates signal charges obtained by photoelectric conversion of the photoelectric conversion unit, and the photoelectric conversion unit. An image sensor in which a plurality of pixels having a transfer unit that transfers the signal charge to the storage unit, a photoelectric conversion unit, and a reset unit that resets the voltage of the storage unit are arranged in a matrix, and incident on the image sensor An imaging apparatus comprising: a light amount adjusting unit that adjusts a light amount of light; and an exposure unit that performs either a global shutter operation or a rolling shutter operation to perform exposure of the image sensor, wherein the exposure unit includes the plurality of exposure units. The photoelectric conversion units and the storage units in all rows of the pixels of the pixel are reset by the reset unit, and after a predetermined exposure time has elapsed since the exposure was started, the plurality of images The signal charges obtained by the photoelectric conversion of the photoelectric conversion units in all rows in the column are transferred to the storage units to complete the exposure, and the light amount adjusting unit is shielded from light after the exposure by the exposure unit is completed. Until now, the amount of incident light to the image sensor is reduced.

  According to the present invention, the exposure period of all rows is matched by simultaneous reset and all row transfer of the image sensor, and then the aperture in the optical system is closed to the minimum aperture to prevent light leakage into the pixel circuit. Reduce. Thus, it is possible to prevent distortion of the captured image by the XY addressing-type image sensor and to suppress deterioration of the captured image due to light leakage into the pixel.

1 is a block diagram illustrating a schematic configuration of an imaging apparatus according to an embodiment of the present invention. (A) is a figure which shows schematic structure of the optical system of FIG. 1, and is a figure which shows schematic structure of the optical system of a form different from the optical system shown in FIG. 2 (a). It is a figure which shows schematic structure of the image pick-up element in FIG. It is a figure which shows the circuit structure of each pixel of the pixel part in FIG. It is a figure which shows the operation timing of rolling shutter operation | movement. It is a figure which shows the operation timing of global shutter operation | movement. (A)-(c) is a figure which shows the exposure state of the center vicinity of an imaging region. It is a figure which shows the operation timing of the global shutter operation | movement in the 4th Embodiment of this invention. It is a figure which shows the operation timing of the global shutter operation | movement in the 5th Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The embodiment described below is an example as means for realizing the present invention, and should be appropriately modified or changed according to the configuration and various conditions of the apparatus to which the present invention is applied. It is not limited to the embodiment.

[First Embodiment]
A first embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 is a block diagram illustrating a schematic configuration of an imaging apparatus according to an embodiment of the present invention.

  The imaging apparatus of this embodiment can be applied to an electronic still camera with a moving image function, a video camera, or the like.

  The imaging apparatus shown in FIG. 1 includes an optical system 101, an imaging element 102, a preprocessing unit 103, a signal processing unit 104, a compression / decompression unit 105, a synchronization control unit 106, an operation unit 107, an image display unit 108, and an image recording unit 109. Prepare.

  The optical system 101 includes a lens for condensing light from a subject on the image sensor 102, a driving mechanism for moving the lens to perform zooming and focusing, a mechanical shutter mechanism, an aperture mechanism, and the like. Among these, the movable unit is driven based on a control signal from the synchronization control unit 106.

  The image sensor 102 is an XY readout type CMOS image sensor or the like, and the timing of exposure, signal readout, reset, and the like is controlled in accordance with a control signal from the synchronization control unit 106.

  The pre-processing unit 103 is a front-end circuit that includes a CDS (Correlated Double Sampling) circuit, an AGC (Auto Gain Control) circuit, an AD converter circuit, and the like, and operates under the control of the synchronization control unit 106. The CDS circuit removes fixed pattern noise caused by variations in the threshold values of the transistors in the pixel circuit by performing CDS processing on the output signal of the image sensor 102, and increases the S / N (Signal / Noise) ratio. Sample and hold to keep it good. The AGC circuit controls the gain by AGC processing. The AD converter circuit converts the analog image signal from the CDS / AGC circuit into a digital image signal.

  The signal processing unit 104 performs white balance adjustment processing, color correction processing, AF (Auto Focus) processing, AE (Auto Focus processing) on the image signal digitized by the preprocessing unit 103 under the control of the synchronization control unit 106. Perform signal processing such as exposure processing.

The compression / decompression unit 105 operates under the control of the synchronization control unit 106, and performs compression coding processing on the image signal from the signal processing unit 104 in a predetermined still image data format such as JPEG method. JPEG: Joint Photographic Coding Experts Group
Further, the compression / decompression unit 105 performs decompression decoding processing on the encoded data of the still image supplied from the synchronization control unit 106. Furthermore, the compression encoding / decompression decoding processing of moving images may be executed by the MPEG method or the like. MPEG: Moving Picture Experts Group
The synchronization control unit 106 is a microcontroller including, for example, a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like. The synchronization control unit 106 performs overall control of each unit of the illustrated imaging apparatus by executing a program stored in a ROM or the like.

  The operation unit 107 includes, for example, various operation keys such as a shutter release button, a lever, and a dial, and outputs a control signal according to an input operation by the user to the synchronization control unit 106.

  The image display unit 108 includes a display device such as an LCD (Liquid Crystal Display) and an interface circuit for the display device. The image display unit 108 generates an image signal to be displayed on the display device from the image signal supplied from the synchronization control unit 106, and supplies the signal to the display device to display an image.

  The image recording unit 109 is realized, for example, as a portable semiconductor memory, an optical disk, an HDD (Hard Disk Drive), a magnetic tape, or the like, and receives an image data file encoded by the compression / decompression unit 105 from the synchronization control unit 106. Remember. Further, the designated data is read based on the control signal from the synchronization control unit 106 and output to the synchronization control unit 106.

  Here, a basic operation in the above-described imaging apparatus will be described.

  Prior to capturing a still image, the image signal output from the image sensor 102 is sequentially supplied to the preprocessing unit 103, subjected to CDS processing and AGC processing, and further converted into a digital image signal by an AD converter. The signal processing unit 104 performs image quality correction processing on the digital image signal from the preprocessing unit 103 and supplies the digital image signal to the image display unit 108 through the synchronization control unit 106 as a camera-through image signal. As a result, the camera-through image is displayed, and the user can adjust the angle of view while viewing the display image. In this state, when the shutter release button of the operation unit 107 is pressed, an image signal for one frame from the image sensor 102 is transmitted to the signal processing unit 104 via the preprocessing unit 103 under the control of the synchronization control unit 106. It is captured. The signal processing unit 104 performs image quality correction processing on the captured image signal for one frame, and supplies the processed image signal to the compression / decompression unit 105. The compression / decompression unit 105 compresses and encodes the input image signal, and supplies the generated encoded data to the image recording unit 109 through the synchronization control unit 106. As a result, the data file of the captured still image is recorded in the image recording unit 109. Also, the recorded still image can be displayed by supplying the processed image signal to the image display unit 108 through the synchronization control unit 106.

  When reproducing a still image data file recorded in the image recording unit 109, the synchronization control unit 106 reads the selected data file from the image recording unit 109 in accordance with an operation input from the operation unit 107, and compresses / decompresses the data file. The data is supplied to the unit 105 to execute the decompression decoding process. The decoded image signal is supplied to the image display unit 108 via the synchronization control unit 106, whereby a still image is reproduced and displayed.

  When recording a moving image, the image signal sequentially processed by the signal processing unit 104 is subjected to compression encoding processing by the compression / decompression unit 105, and the encoded data of the generated moving image is sequentially converted into the image recording unit 109. Transfer to and record. A moving image data file is read from the image recording unit 109, supplied to the compression / decompression unit 105, decompressed and decoded, and supplied to the image display unit 108, thereby displaying the moving image.

  FIG. 2A is a diagram showing a schematic configuration of the optical system 101 in FIG.

  The optical system 101 includes a first lens group 1001, a second lens group 1002, and a diaphragm 1003 as a light amount adjusting unit provided between the first lens group 1001 and the second lens group 1002. Further, the optical system 101 includes a neutral density filter 1004 as a light amount adjusting unit, a mechanical shutter 1005 as a light shielding unit, and a driving unit 1006 for driving and controlling them.

  Each of the first lens group 1001 and the second lens group 1002 is composed of at least one lens, and can be moved in the optical axis direction under the control of the driving unit 1006. Therefore, a zoom function and a focusing function are realized. It is possible to do. Note that a third lens group including at least one lens may be further provided between the second lens group 1002 and the mechanical shutter 1005, and the focusing function may be realized using the third lens group.

  The diaphragm 1003 is an iris diaphragm in which the diameter of the diaphragm aperture can be continuously changed by combining a plurality of diaphragm blades. For this reason, the light quantity of incident light can be adjusted continuously by control by the drive unit 1006. The shape of the aperture opening is ideally circular, but normally it has a number of corners corresponding to the number of aperture blades used, so that an aperture with more aperture blades may be used if necessary. Alternatively, a diaphragm having a plurality of apertures may be used interchangeably.

  The neutral density filter 1004 is a filter typified by an ND (Neutral Density) filter, and can reduce light entering the lens in a balanced manner without being biased to a specific color. In the present embodiment, the neutral density filter 1004 can be taken in and out under the control of the drive unit 1006. Further, the diaphragm 1003 may be controlled to be inserted after reaching the minimum diameter, or may be controlled to be inserted from an intermediate diameter near the minimum diameter. In this way, if the neutral density filter 1004 is inserted while avoiding the maximum aperture of the diaphragm 1003, the aperture of the neutral density filter 1004 can be reduced. Small size and simplification are possible.

  In the present embodiment, the optical system is described as having a neutral density filter that can be taken in and out, but it is also explained that an optical system that is not equipped with a neutral density filter can be applied by controlling only the diaphragm. To do.

  The mechanical shutter 1005 can block incident light under the control of the driving unit 1006. In the present embodiment, it is assumed that an image capturing area is shielded in the vertical direction, such as a rear curtain of a focal plane shutter. In addition, the mechanical shutter 1005 may be configured to be closed by two blades so that light is shielded from the left and right or from the top and bottom.

  FIG. 2B is a diagram illustrating a schematic configuration of the optical system 101 having a form different from that of the optical system 101 illustrated in FIG. 2A, and an interchangeable lens imaging apparatus including a camera body 1101 and an interchangeable lens 1102. ing.

  The camera main body 1101 and the interchangeable lens 1102 are configured to be detachable, mechanically connected by the camera main body side mount 1103 and the interchangeable lens side mount 1104, and electrically connected by the camera main body side contact 1105 and the interchangeable lens side contact 1106. Connect. 2B illustrates the optical system of the interchangeable lens imaging apparatus, the camera body 1101 is not illustrated except for the optical system 101, the imaging element 102, and the synchronization control unit 106 in FIG. .

  The optical system on the camera body 1101 side includes a mechanical shutter 1005 as a light shielding unit and a shutter driving unit 1008 that controls driving of the mechanical shutter 1005. The mechanical shutter 1005 can block incident light under the control of the shutter driving unit 1008. Similar to the optical system 101 shown in FIG. 2A, a device that shields the imaging region in the vertical direction, such as a rear curtain of a focal plane shutter, or a focal plane shutter may be used.

  The shutter drive unit 1008 operates under the control of a control signal from the synchronization control unit 106.

  The optical system on the interchangeable lens 1102 side includes a first lens group 1001, a second lens group 1002, and a diaphragm 1003 as a light amount adjusting unit provided between the first lens group 1001 and the second lens group 1002. Furthermore, a neutral density filter 1004 as a light amount adjusting unit and an interchangeable lens driving unit 1007 for driving and controlling these are provided. The description of the first lens group 1001, the second lens group 1002, the stop 1003, and the neutral density filter 1004 is the same as in FIG.

  The interchangeable lens driving unit 1007 operates under the control of a control signal from the synchronization control unit 106 sent via the camera body side contact 1105 and the interchangeable lens side contact 1106. The electrical connection between the camera body side contact 1105 and the interchangeable lens side contact 1106 is performed by communication performed with the synchronization control unit 106. For example, a control signal for the interchangeable lens driving unit 1007, information on a memory (not shown) in the interchangeable lens 1102, or a state of the first lens group 1001, the second lens group 1002, the stop 1003, and the neutral density filter 1004 is shown. There is information. Furthermore, the power supply to the electric circuit and motor which are not shown in figure which comprises the interchangeable lens drive part 1007 is also included.

  In the present embodiment, the interchangeable lens is described as having a neutral density filter that can be taken in and out. However, in most interchangeable lenses that are not equipped with a neutral density filter, the present invention can be applied only by controlling the diaphragm. Also explained.

  FIG. 3 is a diagram illustrating a schematic configuration of the image sensor 102 in FIG. 1.

  The image sensor 102 is a CMOS image sensor. As shown in FIG. 3, the image sensor 102 includes a pixel unit (imaging region) 210, a constant current unit 220, a column signal processing unit 230, a vertical selection unit 240, a horizontal selection unit 250, and a horizontal signal line 260 on a semiconductor substrate 200. , An output processing unit 270, and a TG 280.

  The pixel unit 210 has a plurality of pixels arranged in a two-dimensional matrix, and each pixel is provided with a pixel circuit described later with reference to FIG. The signal of each pixel from the pixel unit 210 is output to the column signal processing unit 230 through a vertical signal line described later for each pixel column.

  In the constant current unit 220, a constant current source for supplying a bias current to each pixel is arranged for each pixel column. The vertical selection unit 240 selects each pixel of the pixel unit 210 one row at a time, and drives and controls the reset operation and readout operation of each pixel.

  The column signal processing unit 230 receives the signal of each pixel for each row through the vertical signal line, performs predetermined signal processing for each column, and temporarily holds the signal. For example, CDS processing, AGC processing, AD conversion processing, and the like are appropriately performed. The horizontal selection unit 250 selects the signals of the column signal processing unit 230 one by one and supplies them to the horizontal signal line 260.

  The output processing unit 270 performs predetermined processing on the signal from the horizontal signal line 260 and outputs the signal to the outside, and includes, for example, a gain control circuit and a color processing circuit. Instead of performing AD conversion by the column signal processing unit 230, it may be performed by the output processing unit 270. A TG (Timing Generator) 280 outputs various pulse signals necessary for the operation of each unit under the control of the synchronization control unit 106.

  FIG. 4 is a diagram illustrating a circuit configuration of each pixel of the pixel unit 210 in FIG.

  As shown in FIG. 4, the pixel 310 includes a photodiode PD11, a transfer transistor M12, an amplification transistor M13, a selection transistor M14, and a reset transistor M15. Each transistor is an n-channel MOSFET (MOS Field-Effect Transistor).

  A row selection signal line 211, a transfer signal line 212, and a reset signal line 213 are connected to the gates of the transfer transistor M12, the selection transistor M14, and the reset transistor M15, respectively. These signal lines extend in the horizontal direction and simultaneously drive pixels included in the same row. This makes it possible to control the operation of a line sequential operation type rolling shutter and an all-row simultaneous operation type global shutter. Further, a vertical signal line 214 is connected to the source of the selection transistor M14, and one end of the vertical signal line 214 is grounded via a constant current source 215.

  The photodiode PD11 accumulates electric charges generated by photoelectric conversion as a photoelectric conversion unit, and the P side is grounded and the N side is connected to the source of the transfer transistor M12. When the transfer transistor M12 is turned on as the transfer unit, the charge of the photodiode PD11 is transferred to the FD (floating diffusion) 216. Since the FD 216 has the parasitic capacitance C16, the charge is stored in this part as the storage unit. .

  The drain of the amplification transistor M13 is set to the power supply voltage Vdd, and the gate is connected to the FD 216. The amplification transistor M13 converts the voltage of the FD 216 into an electric signal. The selection transistor M14 is for selecting a pixel from which a signal is read out in units of rows, and has a drain connected to the source of the amplification transistor M13 and a source connected to the vertical signal line 214. When the selection transistor M14 is turned on, the amplification transistor M13 and the constant current source 215 form a source follower, so that a voltage corresponding to the voltage of the FD 216 is output to the vertical signal line 214.

  The drain of the reset transistor M15 is set to the power supply voltage Vdd, and the source is connected to the FD 216. The reset transistor M15, as a reset unit, resets the voltage of the FD 216 to the power supply voltage Vdd.

  Hereinafter, a basic operation example of the pixel unit 210 will be described. In the illustrated circuit, two types of electronic shutter operations, a rolling shutter and a global shutter, can be performed.

<Rolling shutter operation control method>
First, when the mechanical shutter 1005 is closed, it is opened. Next, the reset time is calculated from the exposure time to be set. When the calculated reset time is reached, the reset transistor M15 is turned on by setting the reset signal line 213 to a high potential for the pixel in the readout start row of the pixel unit 210. Next, the transfer signal line 212 is set to a high potential to turn on the transfer transistor M12. As a result, the FD 216 and the photodiode PD11 are reset.

  Subsequently, exposure of the photodiode PD11 is started by setting the transfer signal line 212 to a low potential and turning off the transfer transistor M12. Next, the reset signal line 213 is set to a low potential to turn off the reset transistor M15. Thereafter, immediately before the end of exposure, the reset signal line 213 in the start row is set to a high potential to turn on the reset transistor M15, thereby setting the FD 216 to the power supply voltage Vdd. In this state, the row selection signal line 211 of the start row is set to a high potential to turn on the selection transistor M14, and then the reset signal line 213 is set to a low potential to turn off the reset transistor M15. A reset voltage corresponding to the voltage of the FD 216 at this time is output to the vertical signal line 214.

  Next, the signal charge generated in the photodiode PD11 is transferred to the FD 216 by setting the transfer signal line 212 to a high potential and turning on the transfer transistor M12. Then, exposure is completed by setting the transfer signal line 212 to a low potential and turning off the transfer transistor M12, and a signal charge voltage proportional to the voltage to which the signal charge transferred to the FD 216 is added is output to the vertical signal line 214. . Here, the difference between the signal charge voltage output to the vertical signal line 214 and the reset voltage is the signal voltage. This signal voltage is extracted by, for example, the CDS process of the column signal processing unit 230 of the corresponding column. Then, each column is sequentially selected by the horizontal selection unit 250, and a pixel signal for one row of the start row is output. Thereafter, after the row selection signal line 211 of the starting row is set to a low potential and the selection transistor M14 is turned off, the reset transistor M15 and the transfer transistor M12 are turned on at the calculated reset time. Exposure is started.

  The readout operation as described above is performed with a delay of one row from the start row in synchronization with the horizontal synchronization signal, and the pixel signals of each row are sequentially output. As a result, the exposure period of each row is shifted for each row.

  FIG. 5 is a diagram illustrating the operation timing of the rolling shutter operation.

  The rolling shutter operation is used for image display and moving image recording during monitoring. When the mechanical shutter 1005 is closed, it is opened. It is assumed that the aperture 1003 and the neutral density filter 1004 are set in advance according to the shooting conditions. In the case of the interchangeable lens type imaging apparatus shown in FIG. 2B, the synchronization control unit 106 sends a control signal to the interchangeable lens 1102 to transmit a control signal for the aperture of the aperture corresponding to the imaging condition and the insertion / extraction of the neutral density filter. 1003 and the neutral density filter 1004 are controlled.

  In FIG. 5, the top is a read start row, the bottom is a read end row, and Vread indicates the read direction. The horizontal axis indicates the elapsed time t.

  First, the reset start time t21 is calculated based on the exposure time to be set. Then, in the reset operation period from timing t21 to t22, the pixel reset operation described above is performed for each row from the readout start row to the readout end row of the pixel portion 210 (output signal 11 in FIG. 5).

  Next, at the timing t23 when the exposure period has passed since the reset of the readout start row, the pixel readout operation described above is started. Then, during the read operation period from timing t23 to t24, a pixel signal is output for each row from the read start row to the read end row of the pixel portion 210 (output signal 41 in FIG. 5). Further, the next reset operation period starts from the next reset start time t25 (output signal 13 in FIG. 5), and the next read operation period starts from the next read start time t26 (output signal 43 in FIG. 5). Further, until the timing t20 is the previous read operation period (output signal 42 in FIG. 5).

  As described above, the image display and the moving image recording at the time of monitoring are realized by performing the synchronous control with the timing t23 to t26 as one cycle.

<Global shutter operation control method>
First, when the mechanical shutter 1005 is closed, it is opened. Next, the reset time is calculated from the exposure time to be set. When the calculated reset time is reached, the reset signal line 213 of all rows is set to a high potential in the pixel unit 210, and the reset transistor M15 is turned on. Next, the transfer signal line 212 of all rows is set to a high potential, and the transfer transistor M12 is turned on. Thereby, the FD 216 and the photodiode PD11 of all the pixels are reset.

  Subsequently, exposure of the photodiodes PD11 of all pixels is started by setting the transfer signal lines 212 of all rows to a low potential and turning off the transfer transistors M12. Next, the reset signal lines 213 of all rows are set to a low potential, and the reset transistors M15 are turned off. Thereafter, immediately before the end of exposure, the reset signal lines 213 of all the rows are set to a high potential to turn on the reset transistors M15, thereby setting the FD 216 of all the pixels to the power supply voltage Vdd.

  Next, the reset signal lines 213 of all rows are set to a low potential, and the reset transistors M15 are turned off. Subsequently, the transfer signal line 212 of all rows is set to a high potential to turn on the transfer transistor M12, whereby the signal charge generated in the photodiode PD11 of all pixels is transferred to the FD 216. Then, exposure is completed by setting the transfer signal lines 212 of all rows to a low potential and turning off the transfer transistors M12, and the FDs 216 of all the pixels are in a state where the transferred signal charges are accumulated. In this state, the mechanical shutter 1005 is operated to shield all pixels from light. Then, after the light shielding is completed, the reading operation from the pixel is started.

  First, the signal charge proportional to the voltage to which the signal charge transferred to the FD 216 is added by turning on the selection transistor M14 by setting the row selection signal line 211 to a high potential for the pixel in the readout start row of the pixel unit 210. The voltage is output to the vertical signal line 214.

  Next, the reset signal line 213 in the starting row is set to a high potential to turn on the reset transistor M15, thereby setting the FD 216 to the power supply voltage Vdd. In this state, the reset signal line 213 in the starting row is set to a low potential and the reset transistor M15 is turned off, so that a reset voltage corresponding to the voltage of the FD 216 at this time is output to the vertical signal line 214. Thereafter, the row selection signal line 211 of the start row is set to a low potential, and the selection transistor M14 is turned off. Here, the difference between the signal charge voltage output to the vertical signal line 214 and the reset voltage is the signal voltage. This signal voltage is extracted by, for example, the CDS process of the column signal processing unit 230 of the corresponding column. Then, each column is sequentially selected by the horizontal selection unit 250, and a pixel signal for one row of the start row is output.

  The readout operation as described above is performed with a delay of one row from the start row in synchronization with the horizontal synchronization signal, and the pixel signals of each row are sequentially output. As a result, the readout period of each row is shifted for each row.

  FIG. 6 is a diagram illustrating the operation timing of the global shutter operation.

  The global shutter operation is used for still image recording. When the mechanical shutter 1005 is closed, it is opened. It is assumed that the aperture 1003 and the neutral density filter 1004 are set in advance according to the shooting conditions. In the case of the interchangeable lens type imaging apparatus shown in FIG. 2B, the synchronization control unit 106 sends a control signal to the interchangeable lens 1102 to transmit a control signal for the aperture of the aperture corresponding to the imaging condition and the insertion / extraction of the neutral density filter. 1003 and the neutral density filter 1004 are controlled.

  In FIG. 6, the top is the read start row and the bottom is the read end row, and Vread indicates the read direction. The horizontal axis indicates the elapsed time t.

  First, the reset time t1 is calculated based on the exposure time to be set. Then, at the reset time t1, the above-described simultaneous reset operation for all rows is performed (operation 10 in FIG. 6).

  Next, at the timing t2 when the exposure period has passed from the reset time t1, the above-described all-row simultaneous transfer operation is performed (all-row simultaneous transfer operation 20 in FIG. 6). Since the light leakage to the FD 216 continues even after the all-row simultaneous transfer operation is performed, the mechanical shutter 1005 is light-shielded from timing t3 to t4 (light-shielding operation 30 in FIG. 6). The mechanical shutter 1005 shields the imaging region from the top to the bottom, and the light shielding is completed at timing t4. Then, light leakage to the FD 216 is eliminated by shielding the light.

  In FIG. 6, the hatched portion 90 indicates the light leakage state for all pixels (all rows) after the simultaneous transfer operation for all rows.

  Light leakage to the FD 216 before timing t2 is reset or taken into the pixel signal, so that light leakage affecting the image is after timing t2 after the all-row simultaneous transfer operation.

  In addition, when the light shielding operation 30 of the mechanical shutter 1005 is just near the center of the imaging region (C in FIG. 6), that is, the time when the light shielding operation 30 and C in FIG. At the timing t5 after the start of the light shielding operation, the pixel readout operation described above is started. Then, during the read operation period from timing t5 to t6, pixel signals are output for each row from the read start row to the read end row of the pixel portion 210 (operation 40 in FIG. 6).

  With the timing as described above, readout of a pixel signal for still image recording is realized.

  FIGS. 7A and 7B are diagrams showing an exposure state near the center of the imaging region (C in FIG. 6). The vertical axis Cint shows the exposure intensity, and the horizontal axis shows the elapsed time t.

  7A and 7B, timings t2 and t7 are the same timings as timings t2 and t7 in FIG. 6, respectively.

  FIG. 7A is a diagram showing an exposure state near the center of the imaging region (C in FIG. 6) when the present invention is not applied. That is, the exposure intensity 50 on the imaging surface and the light leakage intensity 60 to the FD 216 of the pixel at that time are shown. Since light leakage occurs when a part of the light incident on the pixel leaks into the FD 216, as shown in FIG. 7A, the light leakage intensity 60 to the FD 216 of the pixel is the exposure intensity on the imaging surface. Proportional to 50. Until timing t7, the exposure intensity 50 and light leakage intensity 60 on the imaging surface are constant regardless of the operation of the imaging device.

  In addition, since light leakage to the FD 216 before the timing t2 is reset or taken into the pixel signal, the light leakage affecting the image is after the timing t2 after the all-row simultaneous transfer operation. Then, as described with reference to FIG. 6, the mechanical shutter 1005 shields the vicinity of the center of the imaging region at timing t7, so that the exposure intensity and light leakage intensity on the imaging surface become zero. Thereby, the amount of light leakage near the center of the imaging region becomes a value obtained by integrating the light leakage intensity 60 during the period from the timing t2 to t7. For this reason, it can be seen that the amount of light leakage is proportional to the time from the timing t2 until the mechanical shutter 1005 shields light.

  As described above, in the case of the global shutter operation in FIG. 6, the light leakage amount gradually increases from the reading start row to the reading end row of the imaging region, so that a vertical difference in light leakage occurs.

  FIG. 7B is a diagram showing an exposure state in the vicinity of the center of the imaging region (C in FIG. 6) when the present invention is applied. The description here is also applicable to an image pickup apparatus having an optical system that does not include a neutral density filter, and an interchangeable lens type image pickup apparatus that includes an interchangeable lens that does not include a neutral density filter.

  In the present embodiment, after the timing t2 at which the all-row simultaneous transfer operation 20 of FIG. 7B is performed, during a period from a timing t8 to a time t9 when a predetermined time considering the completion of the all-row simultaneous transfer operation has elapsed. Control is performed so that the aperture 1003 is closed.

  Timing t8 is the timing for starting to close the aperture 1003, and timing t9 is the timing for ending the control for closing the aperture 1003, or the timing for the aperture 1003 to reach the minimum aperture.

  In the case of an interchangeable lens imaging device, the diaphragm 1003 is controlled as follows. The synchronization control unit 106 sends a control signal for starting the closing operation of the diaphragm 1003 to the interchangeable lens 1102 at timing t8. Further, the synchronization control unit 106 sends a control signal for ending the operation of closing the aperture 1003 to the interchangeable lens 1102 at timing t9. Note that the control of the diaphragm 1003 may be stopped by transmitting information indicating that the diaphragm 1003 has the minimum diameter from the interchangeable lens 1102 to the synchronization control unit 106.

  FIG. 7B shows the exposure intensity 51 on the imaging surface before the timing t8 at which the stop 1003 starts to close and the intensity 61 of light leakage to the FD 216 of the pixel at that time. Further, the exposure intensity 52 on the imaging surface during the period from the timing t8 to t9 when the operation of closing the aperture 1003 is performed, and the intensity 62 of light leakage to the FD 216 of the pixel at that time are shown. Furthermore, the exposure intensity 53 on the imaging surface after the timing t9 when the operation of closing the diaphragm 1003 is completed, and the intensity 63 of light leakage to the FD 216 of the pixel at that time are shown. At timing t7, the mechanical shutter 1005 shields the vicinity of the center of the imaging region, so that the exposure intensity and light leakage intensity on the imaging surface become zero. Accordingly, the difference between the light leakage intensity 61 and the light leakage intensity 63 is a decrease in light leakage due to the effect of closing the diaphragm 1003.

  As described above, the global shutter operation by all-line simultaneous reset and all-line simultaneous transfer solves the problem that the moving subject appears in an inclined state and closes the aperture after all-line simultaneous transfer. As a result, the light leakage intensity can be greatly reduced, and the vertical difference in light leakage can be reduced.

  In addition, since the diaphragm 1003 in the present embodiment is an iris diaphragm, the amount of light can be continuously adjusted under the control of the drive unit 1006. For this reason, during the period from timing t8 to t9, the exposure intensity 51 and the light leakage intensity 61 on the imaging surface also gradually decrease.

  Also, if the operating speed of the diaphragm 1003 is large, the amount of light can be reduced quickly, so that the light leakage intensity also decreases rapidly. Therefore, it may be controlled to further reduce the light leakage by operating the diaphragm operating speed when reducing the light leakage faster than the diaphragm operating speed when setting according to the photographing conditions.

  In the case of an interchangeable lens imaging device, the synchronization control unit 106 corresponds to the control information corresponding to the operating speed of the aperture when setting according to the shooting conditions and the operating speed of the aperture when reducing light leakage earlier than that. Control information to be stored is stored. Then, a control signal corresponding to the operating speed of the diaphragm when reducing light leakage is sent to the interchangeable lens 1102.

  In the case of an optical system configured so that the diaphragm 1003 is completely closed, the diaphragm 1003 may be controlled to be completely closed. As a result, the image pickup surface is completely shielded from light, so that light leakage does not occur after the stop 1003 is fully closed. Therefore, the light shielding operation 30 of the mechanical shutter 1005 may be omitted.

  Further, in the present embodiment, since the exposure state of FIG. 7B can be realized, an imaging device having an optical system not equipped with a neutral density filter or an interchangeable lens not equipped with a neutral density filter is mounted. It is also applicable to an interchangeable lens imaging device.

  It is clear that the same effects as those of the present embodiment can be obtained even in the operation as described above. When a still image is captured, if the exposure time is relatively long, for example, 0.1 seconds or more, the image is blurred when the moving subject is imaged. In such a case, even if an electronic shutter operation by the rolling shutter method is performed, the distortion of the captured image due to the electronic shutter operation does not significantly affect the image quality.

  Therefore, when the shutter release button is pressed, the global shutter operation and the mechanical shutter operation as shown in FIG. 6 are performed only when the exposure time calculated by the signal processing unit 104 or the synchronization control unit 106 is a predetermined value or less. Shooting control is used together. Other than that, photographing control may be performed using a rolling shutter operation as shown in FIG. Thereby, an extra operation of the mechanical shutter is suppressed, and there is an effect that power consumption can be reduced.

[Second Embodiment]
Next, an image pickup apparatus according to a second embodiment of the present invention will be described with reference to FIGS. In the present embodiment, the basic configuration and operation of the image pickup apparatus and the basic configuration and operation of the image pickup element are the same as those in the first embodiment.

  In the present embodiment, after the timing t2 at which the all-row simultaneous transfer operation 20 of FIG. 7B is performed, during a period from a timing t8 to a time t9 when a predetermined time considering the completion of the all-row simultaneous transfer operation has elapsed. Control is made so that the neutral density filter 1004 is inserted.

  Timing t8 is the timing when the neutral density filter 1004 is started to be inserted, and timing t9 is the timing when the neutral density filter 1004 is completely inserted.

  In the case of an interchangeable lens imaging device, the neutral density filter 1004 is controlled as follows. The synchronization control unit 106 sends a control signal for starting insertion of the neutral density filter 1004 to the interchangeable lens 1102 at timing t8. Further, the synchronization control unit 106 sends a control signal for terminating the insertion of the neutral density filter 1004 to the interchangeable lens 1102 at timing t9. Note that the control of the neutral density filter 1004 may be stopped by transmitting information indicating that the neutral density filter 1004 has been inserted from the interchangeable lens 1102 to the synchronization control unit 106.

  FIG. 7B shows the exposure intensity 51 on the imaging surface before the insertion start timing t8 of the neutral density filter 1004 and the light leakage intensity 61 to the FD 216 of the pixel at that time. Further, the exposure intensity 52 on the imaging surface during the period from the timing t8 to t9 when the neutral density filter 1004 performs the insertion operation, and the light leakage intensity 62 to the FD 216 of the pixel at that time are shown. Further, the exposure intensity 53 on the imaging surface after the insertion completion timing t9 of the neutral density filter 1004 and the intensity 63 of light leakage to the FD 216 of the pixel at that time are shown. At timing t7, the mechanical shutter 1005 shields the vicinity of the center of the imaging region, so that the exposure intensity and light leakage intensity on the imaging surface become zero. As a result, the difference between the light leakage intensity 61 and the light leakage intensity 63 is a decrease in light leakage due to the insertion effect of the neutral density filter 1004.

  As described above, the global shutter operation by simultaneous reset of all rows and simultaneous transfer of all rows solves the problem that the moving subject appears in an inclined state, and by inserting a neutral density filter after simultaneous transfer of all rows, The light leakage intensity can be greatly reduced. As a result, the vertical difference in light leakage can be reduced.

  Further, if the insertion speed (operation speed) of the neutral density filter 1004 is high, the amount of light can be reduced quickly, so that the light leakage intensity also decreases rapidly. Therefore, it is possible to further reduce the light leakage by operating the neutral density filter operating speed when reducing the light leakage faster than the operational speed of the neutral density filter when setting according to the photographing conditions. .

  In the case of an interchangeable-lens imaging device, the synchronization control unit 106 controls control information corresponding to the operation speed of the neutral density filter when setting in accordance with the imaging conditions and the neutral density filter for reducing light leakage earlier than that. Control information corresponding to the operation speed is stored. Then, a control signal corresponding to the operation speed of the neutral density filter when reducing light leakage is sent to the interchangeable lens 1102.

  In addition, a plurality of neutral density filters 1004 having different light attenuation levels may be prepared, and control may be performed to switch according to shooting conditions such as exposure time and ISO sensitivity. At this time, the ratio of the exposure intensity 51 on the imaging surface and the exposure intensity 53 on the imaging surface is the attenuation of light of the neutral density filter 1004. Therefore, it is possible to further reduce the light leakage by controlling to select a neutral density filter whose attenuation when reducing the light leakage is larger than the attenuation when setting according to the photographing conditions. .

  In the case of an interchangeable lens imaging apparatus, the synchronization control unit 106 stores information on the neutral density filter when setting in accordance with imaging conditions and information on the neutral density filter when reducing light leakage. Then, a control signal for inserting a neutral density filter for reducing light leakage is sent to the interchangeable lens 1102.

  It is clear that the same effects as those of the present embodiment can be obtained even in the operation as described above.

[Third Embodiment]
Next, an imaging apparatus according to a third embodiment of the present invention will be described with reference to FIGS. In the present embodiment, the basic configuration and operation of the image pickup apparatus and the basic configuration and operation of the image pickup element are the same as those in the first embodiment.

  In the present embodiment, after the timing t2 at which the all-row simultaneous transfer operation 20 in FIG. 7C is performed, control is performed so that the aperture 1003 is closed during a period from the timing t8 to t9, and further, from the timing t10 to t11. Control is performed so that the neutral density filter 1004 is inserted during the period.

  Timing t8 is the timing for starting to close the diaphragm 1003, and timing t9 is the timing for ending the control for closing the diaphragm 1003, or the timing for setting the diaphragm 1003 to the minimum aperture. In addition, timing t10 is timing when the neutral density filter 1004 is started to be inserted, and timing t11 is timing when the neutral density filter 1004 is completely inserted.

  In the case of an interchangeable lens imaging device, the diaphragm 1003 is controlled as follows. That is, the synchronization control unit 106 sends a control signal for starting the closing operation of the diaphragm 1003 to the interchangeable lens 1102 at timing t8, and the synchronization control unit 106 exchanges a control signal for ending the closing operation of the diaphragm 1003 at timing t9. Send to lens 1102. Note that the control of the diaphragm 1003 may be stopped by transmitting information indicating that the diaphragm 1003 has the minimum diameter from the interchangeable lens 1102 to the synchronization control unit 106.

  Further, the neutral density filter 1004 is controlled as follows. That is, the synchronization control unit 106 sends a control signal for starting insertion of the neutral density filter 1004 to the interchangeable lens 1102 at timing t10, and sends a control signal for terminating insertion of the neutral density filter 1004 at timing t11. Is sent to the interchangeable lens 1102. Note that the control of the neutral density filter 1004 may be stopped by transmitting information indicating that the neutral density filter 1004 has been inserted from the interchangeable lens 1102 to the synchronization control unit 106.

  FIG. 7C shows the exposure intensity 51 on the imaging surface before the timing t8 when the stop 1003 starts to close and the intensity 61 of light leakage to the FD 216 of the pixel at that time. Further, the exposure intensity 52 on the imaging surface during the period from the timing t8 to t9 when the diaphragm 1003 is closed, and the light leakage intensity 62 to the FD 216 of the pixel at that time are shown. Furthermore, the exposure intensity 53 on the imaging surface after the timing t9 when the operation of closing the diaphragm 1003 is completed, and the intensity 63 of light leakage to the FD 216 of the pixel at that time are shown.

  Further, the exposure intensity 54 on the imaging surface during the period from the timing t10 to t11 when the neutral density filter 1004 performs the insertion operation, and the intensity 64 of light leakage to the FD 216 of the pixel at that time are shown. Further, the exposure intensity 55 on the imaging surface after the insertion completion timing t11 of the neutral density filter 1004 and the intensity 66 of light leakage to the FD 216 of the pixel at that time are shown. At timing t7, the mechanical shutter 1005 shields the vicinity of the center of the imaging region, so that the exposure intensity and light leakage intensity on the imaging surface become zero. Accordingly, the difference between the light leakage intensity 61 and the light leakage intensity 65 is a decrease in light leakage due to the effects of the diaphragm 1003 and the neutral density filter 1004.

  As described above, the global shutter operation by simultaneous reset of all lines and simultaneous transfer of all lines solves the problem of moving subjects appearing in an inclined state, and after the simultaneous transfer of all lines, the aperture is closed and a neutral density filter is inserted. . As a result, the light leakage intensity can be greatly reduced, and the vertical difference in light leakage can be reduced.

  Further, in the present embodiment, the neutral density filter 1004 is inserted after the operation of closing the diaphragm 1003 is completed, but the present invention is not limited to this. For example, the neutral density filter 1004 may be inserted before the diaphragm 1003 closing operation is started, or the neutral density filter 1004 may be inserted in the middle of the diaphragm 1003 closing operation. Alternatively, the diaphragm 1003 may be set to an intermediate aperture state before reaching the minimum aperture, and then the neutral density filter 1004 may be inserted.

  Also, if the operating speed of the diaphragm 1003 is large, the amount of light can be reduced quickly, so that the light leakage intensity also decreases rapidly. Therefore, it may be controlled to further reduce the light leakage by operating the diaphragm operating speed when reducing the light leakage faster than the diaphragm operating speed when setting according to the photographing conditions.

  In the case of an interchangeable lens imaging device, the synchronization control unit 106 corresponds to the control information corresponding to the operating speed of the aperture when setting according to the shooting conditions and the operating speed of the aperture when reducing light leakage earlier than that. Control information to be stored is stored. Then, a control signal corresponding to the operating speed of the diaphragm when reducing light leakage is sent to the interchangeable lens 1102.

  Further, if the insertion speed (operation speed) of the neutral density filter 1004 is high, the amount of light can be reduced quickly, so that the light leakage intensity also decreases rapidly. Therefore, it is possible to further reduce the light leakage by operating the neutral density filter operating speed when reducing the light leakage faster than the operational speed of the neutral density filter when setting according to the photographing conditions. .

  In the case of an interchangeable-lens imaging device, the synchronization control unit 106 controls control information corresponding to the operation speed of the neutral density filter when setting in accordance with the imaging conditions and the neutral density filter for reducing light leakage earlier than that. Control information corresponding to the operation speed is stored. Then, a control signal corresponding to the operation speed of the neutral density filter when reducing light leakage is sent to the interchangeable lens 1102.

  In addition, a plurality of neutral density filters 1004 having different light attenuation levels may be prepared, and control for switching according to photographing conditions such as exposure time and ISO sensitivity may be performed. At this time, the ratio of the exposure intensity 51 on the imaging surface and the exposure intensity 53 on the imaging surface is the attenuation of light of the neutral density filter 1004. Therefore, it is possible to further reduce the light leakage by controlling to select a neutral density filter whose attenuation when reducing the light leakage is larger than the attenuation when setting according to the photographing conditions. .

  In the case of an interchangeable lens imaging apparatus, the synchronization control unit 106 stores information on the neutral density filter when setting in accordance with imaging conditions and information on the neutral density filter when reducing light leakage. Then, a control signal for inserting a neutral density filter for reducing light leakage is sent to the interchangeable lens 1102.

  It is clear that the same effects as those of the present embodiment can be obtained even in the operation as described above.

[Fourth Embodiment]
Next, with reference to FIG. 8 in addition to FIG. 1 to FIG. 7, an imaging apparatus according to a fourth embodiment of the present invention will be described. In the present embodiment, the basic configuration and operation of the image pickup apparatus and the basic configuration and operation of the image pickup element are the same as those in the first embodiment.

  FIG. 8 is a diagram showing the operation timing of the global shutter operation in the fourth embodiment of the present invention.

  Similar to FIG. 6 in the first embodiment, the global shutter operation is used for still image recording. In this embodiment, the mechanical shutter 1005 shields the imaging region from the bottom to the top from timing t3, and the shielding is completed at the timing t4 (shading operation 31 in FIG. 8). Further, when the light shielding operation 31 of the mechanical shutter 1005 has just come to the vicinity of the center of the imaging region (C in FIG. 8), that is, the time when the light shielding operation 31 and C in FIG. Timing t7 in FIG. 8 is the same as timing t7 in FIG. Other operations are the same as those in FIG.

  Light leakage to the FD 216 is eliminated by the light shielding operation of the mechanical shutter 1005 (light shielding operation 31 in FIG. 8). Further, regarding the light leakage to the FD 216, the readout operation from the timing t5 to the time t6 (operation 40 in FIG. 8) is performed, and the light is added to the pixel signal as light leakage and output. The leakage of light is up to the reading operation (operation 40 in FIG. 8). The state of light leakage for all pixels (all rows) after the all-row simultaneous transfer operation in this embodiment is a hatched portion 91 shown in FIG.

  Also in the global shutter operation shown in FIG. 8, the aperture 1003 or the neutral density filter 1004 is used in the vicinity of the center of the imaging region (C in FIG. 8) shown in FIG. 7B in the first embodiment and the second embodiment. An exposure state can be realized.

  Further, by using both the diaphragm 1003 and the neutral density filter 1004, it is possible to realize the exposure state near the center of the imaging region (C in FIG. 8) shown in FIG. 7C in the third embodiment.

  Furthermore, it goes without saying that this embodiment is also applicable to an interchangeable lens imaging device.

  Also in this embodiment, since the exposure state of FIG. 7B in the first embodiment can be realized, an imaging apparatus having an optical system that does not include a neutral density filter and a neutral density filter are not provided. The present invention can also be applied to an interchangeable lens imaging device equipped with an interchangeable lens.

  As described above, in the present embodiment, the global shutter operation by simultaneous reset of all rows and simultaneous transfer of all rows solves the problem that the moving subject appears in an inclined state and closes the aperture after simultaneous transfer of all rows. As a result, the light leakage intensity can be greatly reduced, and the vertical difference in light leakage can be reduced.

  In this embodiment, the example in which the mechanical shutter performs the light shielding operation from the bottom to the top has been described. However, the present invention is not limited to this embodiment. For example, a mechanical shutter that performs a light shielding operation from the top to the bottom and a mechanical shutter that performs a light shielding operation from the bottom to the top may be combined. Alternatively, a mechanical shutter that performs a light shielding operation from the left to the right direction or a mechanical shutter that performs a light shielding operation from the right to the left direction may be used. Further, a mechanical shutter that simultaneously performs a light shielding operation from the left and right toward the center may be used.

  It is clear that the same effects as those of the present embodiment can be obtained even in the operation as described above.

[Fifth Embodiment]
Next, with reference to FIG. 9 in addition to FIG. 1 to FIG. 7, an imaging apparatus according to a fifth embodiment of the present invention will be described. In the present embodiment, the basic configuration and operation of the image pickup apparatus and the basic configuration and operation of the image pickup element are the same as those in the first embodiment.

  FIG. 9 is a diagram showing the operation timing of the global shutter operation in the fifth embodiment of the present invention.

  Similar to FIG. 6 in the first embodiment, the global shutter operation is used for still image recording. In this embodiment, the operation does not use the mechanical shutter 1005. Other operations are the same as those in FIG.

  Regarding the light leakage to the FD 216, the readout operation from the timing t5 to the timing t6 (operation 40 in FIG. 9) is performed, and the light is added to the pixel signal as light leakage and output. The leakage is up to the read operation (operation 40 in FIG. 9). The state of light leakage for all pixels (all rows) after the all-row simultaneous transfer operation in the present embodiment is a hatched portion 92 shown in FIG.

  Next, when the reading operation 40 has just come to the vicinity of the center of the imaging region (C in FIG. 9), that is, the time when 40 and C in FIG.

  Here, description will be made assuming that the timing t7 in FIG. 7 is the same timing as the timing t17 in FIG.

  Also in the global shutter operation shown in FIG. 9, the aperture 1003 or the neutral density filter 1004 is used in the vicinity of the center of the imaging region (C in FIG. 9) shown in FIG. 7B in the first embodiment and the second embodiment. An exposure state can be realized.

  Further, by using both the diaphragm 1003 and the neutral density filter 1004, it is possible to realize an exposure state near the center of the imaging region (C in FIG. 9) shown in FIG. 7C in the third embodiment. Furthermore, it goes without saying that this embodiment is also applicable to an interchangeable lens imaging device.

  Also in this embodiment, since the exposure state of FIG. 7B in the first embodiment can be realized, an imaging apparatus having an optical system that does not include a neutral density filter and a neutral density filter are not provided. The present invention can also be applied to an interchangeable lens imaging device equipped with an interchangeable lens.

  As described above, the global shutter operation by all-line simultaneous reset and all-line simultaneous transfer solves the problem that the moving subject appears in an inclined state and closes the aperture after all-line simultaneous transfer. As a result, the light leakage intensity can be greatly reduced, and the vertical difference in light leakage can be reduced.

  The present invention can also be 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 a computer (or CPU, MPU, or the like) of the system or apparatus reads the program. It is a process to be executed.

DESCRIPTION OF SYMBOLS 101 Optical system 102 Image pick-up element 106 Synchronization control part 1001 1st lens group 1002 2nd lens group 1003 Aperture 1004 Neutral filter 1005 Mechanical shutter 1006 Drive part

Claims (12)

A photoelectric conversion unit that photoelectrically converts incident light, a storage unit that stores signal charges obtained by photoelectric conversion of the photoelectric conversion unit, a transfer unit that transfers the signal charges from the photoelectric conversion unit to the storage unit, and the photoelectric conversion And an image sensor in which a plurality of pixels having a reset unit for resetting the voltage of the storage unit are arranged in a two-dimensional matrix, a light amount adjusting means for adjusting the amount of incident light to the image sensor, and a global shutter An image pickup apparatus comprising: an exposure unit that performs either an operation or a rolling shutter operation to perform exposure of the image pickup device;
The exposure unit is configured to reset all photoelectric conversion units and storage units of all rows in the plurality of pixels by the reset unit and start exposure, and then, after a predetermined exposure time has elapsed, all the pixels in the plurality of pixels Transfer the signal charge obtained by photoelectric conversion of each photoelectric conversion unit in the row to each storage unit to complete the exposure,
The image pickup apparatus according to claim 1, wherein the light amount adjusting unit reduces the amount of incident light to the image pickup device after the exposure by the exposure unit is completed and before light shielding is performed.   The image pickup apparatus according to claim 1, wherein the light amount adjusting unit includes a stop, and the exposure unit closes the stop to reduce the amount of light incident on the image sensor.   The light amount adjusting means includes a diaphragm and a neutral density filter, and the exposure means closes the diaphragm and inserts the neutral density filter to reduce the quantity of incident light to the image sensor. The imaging apparatus according to claim 1.   4. The image pickup apparatus according to claim 2, wherein the stop is configured to be completely closed, and the exposure unit closes the stop completely to block incident light to the image pickup device.   2. The image pickup apparatus according to claim 1, wherein the light amount adjusting unit includes a neutral density filter, and the exposure unit inserts the neutral density filter to reduce a light amount of incident light to the image sensor. The light amount adjusting means is composed of a plurality of neutral density filters having different light attenuation levels,
The exposure unit selects the light quantity filter so that the attenuation when the light quantity of the incident light to the image sensor is reduced is larger than the attenuation level set in accordance with the imaging condition of the imaging device. The imaging apparatus according to claim 1, wherein the adjustment unit is controlled.   The exposure unit controls the operation speed when the light amount adjustment unit reduces the light amount of the incident light to the image sensor to be higher than an operation speed set in accordance with a photographing condition of the imaging device. The imaging apparatus according to claim 1, wherein   The light-blocking unit that blocks light incident on the image sensor, wherein the light-blocking unit performs light blocking after the light amount of the light incident on the image sensor is reduced by the light amount adjusting unit. The imaging device according to any one of 1 to 7.   The exposure unit reads the signal charge from each storage unit for each row at the same time after the exposure is completed. 9. The image pickup apparatus according to claim 8, wherein the image pickup apparatus is controlled so as to shield light upward.   The imaging apparatus according to claim 1, wherein the storage unit is a floating diffusion.   The lens group for condensing incident light on the image sensor and a portion including the light amount adjusting means are configured to be detachable from the main body of the image pickup apparatus. The imaging device according to item. A photoelectric conversion unit that photoelectrically converts incident light, a storage unit that stores signal charges obtained by photoelectric conversion of the photoelectric conversion unit, a transfer unit that transfers the signal charges from the photoelectric conversion unit to the storage unit, and the photoelectric conversion And an image sensor in which a plurality of pixels having a reset unit for resetting the voltage of the storage unit are arranged in a two-dimensional matrix, a light amount adjusting means for adjusting the amount of incident light to the image sensor, and a global shutter An imaging apparatus comprising: an exposure unit that performs either an operation or a rolling shutter operation to expose the image sensor;
The exposure means resets each photoelectric conversion unit and each storage unit in all rows in the plurality of pixels by the reset unit and starts exposure, and then after a predetermined exposure time has elapsed, all the pixels in the plurality of pixels A step of transferring the signal charge obtained by photoelectric conversion of each photoelectric conversion unit in a row to each storage unit and terminating exposure;
The exposure means, after the exposure is completed, simultaneously reading out the signal charge from each storage unit for each row;
A step of reducing the amount of incident light to the image sensor from when the light amount adjusting means is shielded after the exposure by the exposure means is completed;
A control method comprising:

Images