JP7187269B2 - Imaging device and its control method - Google Patents

Description

The present invention relates to an exposure control technique for an imaging device based on the relationship between the position of a focus lens that vibrates when stopped and a predetermined range.

In autofocus (hereinafter also referred to as AF) control of an imaging device, a process of moving a focus lens and stopping it at a target position after detection of a focus state is performed. The focus lens vibrates in the optical axis direction due to the inertial force when it stops. When exposure is started immediately after the focus lens reaches the target position and the driving motor stops, the focus lens may be displaced from the target position beyond a predetermined range due to vibration. The predetermined range is a range determined in order to guarantee image quality, and displacement of the focus lens exceeding this range causes deterioration in image quality.

The settling time from when the driving motor stops to when the displacement due to the vibration of the focus lens converges within a predetermined range is experimentally determined, and the image quality is prevented from deteriorating by starting exposure after the settling time has elapsed. There is a way. However, providing the settling time reduces the time (hereinafter referred to as release time lag) from when the user presses the release button with the intention of starting imaging to when exposure of the image sensor actually starts. hinder.

The apparatus disclosed in Japanese Patent Application Laid-Open No. 2002-200001 performs continuous shooting at regular intervals, determines whether or not the amount of image blur in the captured image is within a predetermined range, and determines whether or not the amount of image blur is within the predetermined range. Only data is stored and synthesized. This makes it possible to achieve both prevention of image quality degradation and reduction of the release time lag. The system disclosed in Patent Document 2 transfers charges converted by the photoelectric conversion unit to the signal holding unit a plurality of times and accumulates the transferred charges collectively. It can be changed at high speed and freely. At the timing when the focus lens is positioned within the predetermined range and when it is not, it is possible to switch between transferring the signal charge to the signal holding unit and discharging it at high speed.

Japanese Patent Application Laid-Open No. 2003-101862 JP 2013-034247 A

By the way, the oscillation period of the focus lens is about several milliseconds, and the time during which the displacement of the focus lens is within a predetermined range during one oscillation is shorter than that. Furthermore, it takes about ten and several milliseconds until the vibration of the focus lens is damped and the displacement converges within a predetermined range.

In the method disclosed in Patent Document 1, it is necessary to read out a plurality of images obtained by continuous shooting, analyze and select the images, and store them. About several tens of milliseconds are required for reading, analyzing, and sorting images. Although the release time lag can be shortened, another problem arises in that it takes a long time to capture the necessary number of images to obtain a desired image and complete all the shooting.

On the other hand, the method disclosed in Japanese Patent Laid-Open No. 2002-200320 can switch between accumulation and discharge of signal charges sufficiently quickly with respect to the vibration period of the focus lens, which is about several milliseconds. However, since the image data cannot be read out during the period in which the signal charges are accumulated in the signal holding unit, it is impossible to determine from the captured image whether the amount of image blur is within the predetermined range.
SUMMARY OF THE INVENTION It is an object of the present invention to provide an imaging apparatus capable of shortening the release time lag while suppressing deterioration in image quality.

An apparatus according to an embodiment of the present invention includes imaging means including a pixel portion having a photoelectric conversion portion and a signal holding portion, driving means for moving a lens for focus adjustment in the optical axis direction, and control means for controlling the imaging means. , provided. The control means sets a range based on a target position of the lens, and transfers signal charges generated in the photoelectric conversion section to the signal holding section when the lens is positioned within the range. The signal charges are discharged when the lens is positioned outside the range, and the signal charges generated in the photoelectric conversion section during the imaging period are transferred to and accumulated in the signal holding section a plurality of times to generate an image signal. to control.

According to the present invention, it is possible to provide an imaging apparatus capable of shortening the release time lag while suppressing deterioration in image quality.

1 is a schematic diagram of the appearance of an imaging device according to an embodiment of the present invention; FIG. 1 is a block diagram showing a schematic configuration of an imaging device according to an embodiment of the present invention; FIG. 2 is a circuit diagram showing a schematic configuration of an imaging device; FIG. FIG. 4 is an explanatory diagram showing operations of a focus lens and an image sensor; 4 is a flowchart for explaining the operation of the imaging device according to the first embodiment; FIG. 10 is an explanatory diagram showing operations of a focus lens and an image sensor of a comparative example; 9 is a flowchart for explaining the operation of an imaging device according to the second embodiment; 10 is a flowchart for explaining the operation of an imaging device according to the third embodiment; It is a schematic diagram showing the configuration of an imaging device according to fourth to sixth embodiments. 3A and 3B are a circuit diagram (A) and a timing chart (B) of one pixel portion in an image sensor; It is explanatory drawing of the exposure state in 4th Embodiment. It is an explanatory view showing another example of the exposure state in the fourth embodiment. It is a figure explaining exposure control in a 4th embodiment. It is a figure explaining the exposure timing in 4th Embodiment. 10 is a flowchart of exposure control in the fourth embodiment; It is explanatory drawing of the exposure state in 5th Embodiment. It is an explanatory view showing another example of the exposure state in the fifth embodiment. It is a figure explaining the problem of the exposure state in 5th Embodiment. It is a figure explaining the solution in the exposure control in 5th Embodiment. 14 is a flowchart of exposure control in the fifth embodiment; It is explanatory drawing of the exposure state in 6th Embodiment. It is a figure explaining the exposure timing in 6th Embodiment.

EMBODIMENT OF THE INVENTION Below, embodiment of this invention is described in detail with reference to an accompanying drawing. INDUSTRIAL APPLICABILITY The present invention can be used, for example, for control of an image pickup device in an image pickup device having an image pickup device capable of split exposure control for which shortening of shooting time is required. Note that in split exposure, short exposures are intermittently repeated multiple times within the exposure time corresponding to the set shutter speed, and the acquired images can be combined to generate a single image. can.

[First embodiment]
FIG. 1 is an external view showing a digital still motion camera as an example of an imaging device according to this embodiment. FIG. 1A is a front view of the imaging device, and FIG. 1B is a rear view of the imaging device. Hereinafter, the positional relationship of each part will be described with the subject side defined as the front side.

An imaging device main body (hereinafter simply referred to as a main body) 151 accommodates an imaging device and a shutter device therein. The imaging optical system 152 includes optical members such as lenses and diaphragms. A movable display unit 153 is provided on the back surface of the main body unit 151 and displays shooting information and images. The display unit 153 has a display luminance range in which an image with a wide dynamic range can be displayed without suppressing the luminance range.

An operation switch (hereinafter referred to as switch ST) 154 is mainly used by the user to shoot still images. The switch ST154 is arranged on the upper surface of the main body part 151 . An operation switch (hereinafter referred to as switch MV) 155 is a switch used to start and stop moving image shooting. A mode selection lever 156 is an operation member for selecting a photographing mode. A menu button 157 is an operation member for shifting to a function setting mode for setting functions of the imaging apparatus. Switches 158 and 159 are an up switch and a down switch, respectively, for changing various setting values. A dial 160 is an operating member for changing various set values. The playback button 161 is an operation member for shifting to a playback mode in which recorded video is played back on the screen of the display unit 153 . Recorded video data is recorded in a recording medium (to be described later) housed in the main unit 151 . Operation members denoted by reference numerals 155 to 161 are arranged on the rear surface of the body portion 151 .

FIG. 2 is a block diagram illustrating the schematic configuration of the imaging device according to the embodiment of the present invention. A focus lens 180 forming the imaging optical system 152 is a lens for focus adjustment. FIG. 2 shows the optical axis 185 of the imaging optical system 152 . A focus lens 180 is driven in the optical axis direction by a motor 186 . A diaphragm 181 is an optical member that adjusts the amount of light passing through the imaging optical system 152 and is controlled by a diaphragm controller 182 . The optical filter 183 limits the wavelength of light incident on the imaging device 184 and the spatial frequencies transmitted to the imaging device 184 .

The imaging device 184 photoelectrically converts an optical image of a subject formed via the imaging optical system 152 and outputs a video signal. The imaging device 184 has a sufficient number of pixels, signal readout speed, color gamut, and dynamic range to satisfy a predetermined standard, for example, the Ultra High Definition Television standard.

The digital signal processing unit 188 acquires the signal output from the imaging element 184 , performs various corrections on the digital video data, performs data compression processing, and outputs the data to the system control unit 178 . The timing generation section 189 outputs various timing signals to the imaging element 184 and the digital signal processing section 188 in accordance with control commands from the system control section 178 .

A system control unit 178 includes a CPU (Central Processing Unit), performs various calculations, and controls the entire imaging apparatus. For example, the system control unit 178 controls the timing generation unit 189 and controls the imaging device 184 according to the pulses generated by the timing generation unit 189 . Further, the system control unit 178 controls focus adjustment and drive control of the diaphragm 182 by means of a motor 186 and a diaphragm control unit 182 .

A switch input unit 179 receives a user's operation and outputs an operation instruction signal to the system control unit 178 . The switch input unit 179 includes a switch ST154, a switch MV155, and an input operation device such as a switch for switching various modes and a touch panel. A memory 190 is a storage unit for temporarily storing video data and the like according to a control command from the system control unit 178 .

Various interface (hereinafter abbreviated as I/F) units are connected to the system control unit 178 . Display I/F unit 191 outputs display data to display unit 153 . A display unit 153 includes a display device such as a liquid crystal display, and displays an image or the like after shooting. A recording I/F unit 192 records and reads data on a recording medium 193 . The recording medium 193 is, for example, a semiconductor memory or the like that is detachable from the main body 151, and records video data, additional data, and the like. A print I/F unit 194 outputs print data (for example, data corresponding to a captured image) to a printer 195 . Printer 195 is, for example, a small inkjet printer. An external I/F unit 196 performs communication processing with an external device 197 such as a computer. A wireless I/F unit 198 performs communication processing via a computer network 199 such as the Internet. A position detection unit 187 of the focus lens 180 will be described later in an embodiment.

Next, the configuration of the imaging element 184 and the process of generating an image signal will be described. FIG. 3 is a circuit diagram partially showing the configuration of the imaging device 184. As shown in FIG. The imaging device 184 includes a large number of pixel units, and FIG. 3 illustrates a pixel unit 300 at the first row and first column (1, 1) and a pixel unit 301 at an arbitrary m row and first column (m, 1). . Since the pixel portion 300 and the pixel portion 301 have the same configuration, the same reference numerals are used for those components. Note that the basic structure of the imaging device 184 having a signal holding unit is disclosed in Patent Document 2, and detailed description thereof is omitted.

A pixel portion 300 illustrated in FIG. 3 includes a photodiode 500, a first transfer transistor 501A, a signal holding portion 507A, and a second transfer transistor 502A. A photodiode (hereinafter referred to as PD) 500 constitutes a photoelectric conversion unit, and a signal holding unit 507A holds a signal after photoelectric conversion. The pixel section 300 further has a third transfer transistor 503 , a floating diffusion (hereinafter referred to as FD) region 508 , a reset transistor 504 , an amplification transistor 505 and a selection transistor 506 .

The imaging element 184 has a configuration in which a large number of pixel portions are arranged in a two-dimensional array. A first transfer transistor 501A in the pixel portion is controlled by a transfer pulse φTX1A, and a second transfer transistor 502A is controlled by a transfer pulse φTX2A. Also, the reset transistor 504 is controlled by a reset pulse φRES, and the selection transistor 506 is controlled by a selection pulse φSEL. Furthermore, the third transfer transistor 503 is controlled by a transfer pulse φTX3. These control pulses are sent to each transistor from a vertical scanning circuit (not shown). Power supply line 520 supplies power supply voltage to transistors 501A, 502A, and 504, and power supply line 521 supplies power supply voltage to transistor 503. FIG. The output of each pixel portion is taken out from the selection transistor 506 to the signal output line 523 .

Operations of the focus lens 180 and the imaging device 184 will be described in detail with reference to FIG. FIG. 4A is a graph showing the operation when the focus lens 180 stops at the target position X0. The horizontal axis is the time axis, and the vertical axis represents the focus lens position in the optical axis direction. The target position X0 is the position of the focus lens 180 for focusing on the subject to be photographed.

The imaging device includes a distance measuring unit that measures the subject distance from the imaging plane to the subject, or a focus detection unit that detects the focal position corresponding to the subject distance. When the user operates the switch ST154, the distance measuring section or focus detecting section starts processing. For example, there is a configuration in which the imaging device 184 has a pair of imaging pixels for distance measurement (not shown). A split-pupil imaging device includes a plurality of microlenses and a plurality of photoelectric conversion units corresponding to each microlens. In the case of a configuration having two photoelectric conversion units corresponding to one microlens, each photoelectric conversion unit outputs image signals from different viewpoints. The system control unit 178 analyzes the paired image signals and performs so-called imaging plane phase difference detection to detect the focus state. However, the configuration is not limited to this, and a configuration including a distance measuring unit capable of performing phase difference detection separately may be employed.

When the user operates switch ST154, the focus state of the imaging optical system is detected. After that, the focus lens 180 starts moving from the initial position indicated by the point O1 toward the target position X0. The focus lens 180 is driven by a motor 186, moves while accelerating and decelerating, and tries to stop at the target position X0. At this time, even if the motor 186 stops at the target position X0, the focus lens 180 vibrates in the optical axis direction due to the inertial force due to the acceleration during deceleration immediately before stopping, and eventually attenuates and converges to the target position X0. The frequency and attenuation of this vibration are unique to the focus lens 180 and its holding mechanism (not shown). That is, since the vibration waveform is determined by the deceleration acceleration (negative acceleration) at the time of stopping, which is the excitation force, the vibration waveform can be predicted from the deceleration acceleration.

If the position of the focus lens 180 is different from the target position X0, the subject may be out of focus. centered. The predetermined range corresponds to the range of coordinates X1 to X2 at the position of the focus lens 180 in the optical axis direction indicated by the vertical axis in FIG. 4(A). Points O2 and O6 represent points at which the position of the focus lens 180 reaches X1, and point O3 represents a point at which the position of the focus lens 180 reaches the target position X0. Points O4 and O5 represent points at which the position of the focus lens 180 reaches X2. In the example of FIG. 4A, the predetermined range is the range from the point O2 to the point O4 and the range from the point O5 to the point O6 for the position of the focus lens 180 . Also, the period from when the focus lens 180 deviates from the point O4 to when it returns to the point O5 is out of the predetermined range.

FIG. 4B is a timing chart showing the driving sequence of the imaging element 184. As shown in FIG. A vertical synchronizing signal φV, a horizontal synchronizing signal φH, and signals φSEL, φRES, and φTX1-3 are shown. In FIG. 4B, φTX1A is written as φTX1, and φTX2A is written as φTX2. Here, it is assumed that the user shoots a still image with an arbitrary shutter speed S1. The timing generator 189 generates pulses according to this timing chart, and the imaging element 184 is controlled. FIG. 4B shows that when the focus lens 180 is positioned within a predetermined range during one imaging period, the signal charges generated by the PD 500 are transferred to the signal holding unit 507A multiple times, accumulated, and added to obtain an image signal. indicates when to generate . Note that the imaging device 184 has many rows of pixel columns in the vertical direction, and FIG. 4B shows the timing of the first row. By scanning in the vertical direction according to the horizontal synchronizing signal, the accumulation operation of all the pixels of the image sensor 184 is performed.

In FIG. 4B, one shooting period corresponds to time t1 when the transfer pulse φTX3(1) of the first row becomes low level to time tn ^* when the vertical synchronization signal φV rises. As a photographing condition, a case is shown in which an exposure amount equivalent to an arbitrary shutter speed S1 is obtained by adding signal charges accumulated multiple times.

First, the motor 186 is driven to move the focus lens 180 toward the target position X0. At time t1 when the focus lens 180 reaches a position where the focus lens 180 falls within a predetermined range provided with the target position X0 as a reference, that is, the point O2, the transfer pulse φTX3(1) of the first row becomes low level. As a result, the third transfer transistor 503 is turned off, the reset of the PD 500 in the first row is released, and accumulation of signal charges starts. That is, exposure is started at this time. After that, when the transfer pulse φTX1(1) of the first row becomes high level, the first transfer transistor 501A is turned on. The signal charge generated and accumulated in the PD 500 of the first row is transferred to the signal holding section 507A holding the charge of the first row.

After the focus lens 180 reaches the point O3 corresponding to the target position X0 and the motor 186 is stopped, the focus lens 180 is further moved by inertial force. A point O4 is the position of the boundary between the inside of the predetermined range and the outside of the predetermined range. At time t1 ^* when the focus lens 180 reaches the point O4, the transfer pulse φTX1(1) of the first row becomes low level. At this time, the first transfer transistor 501A is turned off, and the process of transferring the signal charge accumulated in the PD 500 of the first row to the signal holding section 507A of the first row is completed. At the same time, the transfer pulse φTX3(1) of the first row becomes high level to turn on the third transfer transistor 503, the accumulation of the signal charge generated in the PD 500 of the first row is completed, and the signal charge is discharged.

The time Δt1 from time t1 to time t1 ^* corresponds to the first accumulation time in one imaging period, and in FIG. ing. Such an accumulation operation is performed when the focus lens 180 is positioned within a predetermined range in one imaging period, and accumulation times 602-1, 602-2, 602-3, . . . 602-n. By adding these multiple accumulation times, an accumulation time equivalent to one accumulation at an arbitrary shutter speed S1 can be obtained. Each accumulation time 602-j (j=1 to n) corresponds to Δtj (=tj ^* -tj). . . , 602-n are the same as in the case of the accumulation time 602-1, description thereof will be omitted.

At time tn ^* after .DELTA.tn has passed from time tn, the timing generator 189 causes the vertical synchronizing signal .phi.V and the horizontal synchronizing signal .phi.H to go high. In synchronization with this signal change, when the reset pulse φRES(1) of the first row becomes low level, the reset transistor 504 of the first row is turned off, and the reset state of the FD region 508 of the first row is released. . At the same time, when the selection pulse φSEL(1) of the first row goes high, the selection transistor 506 of the first row is turned on, and the accumulation times 602-1 to 602-n from time t1 to tn ^* are added. It becomes possible to read out the image signal of the first row.

The exposure time corresponding to the shutter speed ^S1 is Δt1+Δt2+Δt3+ . The time when the period from time tn, which is the final exposure period, to tn ^* has elapsed, that is, the shooting end time is tn ^* .

At the same time that the reset of the pixel portion is released and image signals can be read out, the transfer pulse φTX2(1) of the first row becomes high level and the second transfer transistor 502A of the first row is turned on. As a result, a signal corresponding to the change in potential of the FD region 508 in the first row is read out to the signal output line 523 through the amplification transistor 505 and the selection transistor 506 in the first row. This signal is supplied to a readout circuit (not shown) and output to the outside as an image signal for the first row. After that, the reset pulse φRES(1) becomes high level and the reset transistor 504 is turned on, so that the FD region 508 in the first row and the signal holding section 507A in the first row are reset. At this time, the selection pulse φSEL(1) for the first row is at low level.

The signal processing of the second row is executed in synchronization with the horizontal sync signal φH after time tn ^* . For example, regarding the timing chart of the signal processing started by the horizontal synchronizing signal φH at time tm, this corresponds to the m-th row. The switch signals can be represented as φSEL(m), φRES(m), φTX3(m), φTX1(m), φTX2(m).
As described above, the accumulation operation is performed only when the focus lens 180 is positioned within a predetermined range, and by adding accumulation times for a plurality of times, an exposure time corresponding to an arbitrary shutter speed S1 can be obtained. .

Next, with reference to FIG. 5, a method for controlling the imaging device 184 will be described in detail. FIG. 5 is a flow chart when exposure and accumulation are performed a plurality of times by the above-described control after the user issues an imaging start instruction. It is assumed that when the user issues an imaging start instruction, the user presses the release button halfway, turns on the switch ST154, and then immediately presses the release button fully.

After the release button is operated, photometry and distance measurement are performed in S001. In photometry, for example, when light that has passed through the imaging optical system 152 is incident on the imaging element 184, the system control unit 178 calculates the luminance of the object from the luminance information. Alternatively, in a configuration in which a sensor for photometry is provided separately, the sensor detects the brightness of the subject. In the distance measurement, for example, imaging plane phase difference detection is performed. When the imaging device 184 has a pair of imaging pixels for range finding, the system control unit 178 analyzes the paired image signals to detect the focus state.

Next, in S002, the system control unit 178 calculates exposure amount adjustment parameters such as shutter speed and aperture value, and the focus lens from the photometry result obtained in S001 and the detection result of the focal distance calculated based on the distance measurement result. 180 to determine the amount of movement in the direction of the optical axis.

In S003, the system control unit 178 determines the speed and acceleration of the focus lens 180 from the amount of movement of the focus lens 180 determined in S002. The memory 190 stores a plurality of patterns of lens drive speed and acceleration data necessary for driving the focus lens 180 according to the amount of movement of the focus lens 180 . The system control unit 178 reads out these pieces of information from the memory 190 and uses them as necessary.

In S004, the system control unit 178 determines operation timings for exposure, accumulation, and ejection in the imaging element 184 based on the lens driving speed and acceleration data determined in S003. The deceleration acceleration immediately before the focus lens 180 stops is determined by the lens drive speed and the acceleration information, and the inertial force that vibrates the focus lens 180 acts as described above. Therefore, it is possible to predict the vibration waveform of the focus lens 180 when the focus lens 180 is driven at the lens driving speed. From the behavior of the focus lens 180 illustrated in FIG. 4A, the time when the focus lens 180 is positioned within the predetermined range can be calculated.

In the example of FIG. 4A, the time t1 is obtained when the focus lens 180 moves from the initial position toward the target position X0 and reaches within a predetermined range based on the target position X0. After that, the time of point O4 at which the focus lens 180 goes out of the predetermined range is obtained as t1 ^* , and the time of point O5 at which the focus lens 180 again enters the predetermined range is obtained as t2. In this way, the times tj and tj ^* are obtained sequentially. At this time, by performing exposure only when the focus lens 180 is within a predetermined range, blurring of the image can be kept within the permissible range and image deterioration can be prevented. For example, between times t1 and t1 ^* when the focus lens 180 is positioned within a predetermined range, the exposure and accumulation timings for transferring and accumulating the signal charges generated by the start of exposure in the PD 500 to the signal holding unit 507A are set. Deterioration of the image can be prevented by setting it. Furthermore, it is possible to set the timing for discharging the signal charges generated in the PD 500 between the times t1 ^* and t2 when the focus lens 180 goes out of the predetermined range. Similarly, the system control unit 178 determines exposure/accumulation/ejection timings up to the photographing end time tn ^* .

In the present embodiment, processing for storing predetermined exposure/accumulation/ejection timing information in the memory 190 is performed based on information on the lens drive speed and acceleration. The system control unit 178 reads out these pieces of information from the memory 190 and uses them as necessary.

In S005, the system control unit 178 notifies the timing generation unit 189 of the exposure/accumulation/ejection timing information determined in S004. The timing generation unit 189 controls the imaging element 184 by generating a pulse according to the exposure/accumulation/ejection timing information and outputting it to the imaging element 184 .

In S006, the system control unit 178 starts driving the motor 186 and starts counting the elapsed time (hereinafter referred to as T). The elapsed time T corresponds to the time indicated by the horizontal axis in the timing charts of FIGS. 4(A) and 4(B). Let the time at the point O1 where the focus lens 180 starts to move in FIG. 4A be the starting point of the elapsed time T, that is, T=0. The operation timing of the imaging element 184 is controlled according to the elapsed time T and the exposure/accumulation/ejection timing information determined in S004.

From S007, the exposure/accumulation/ejection described with reference to FIG. 4 are performed. At S007, a reset operation is performed to discharge the charge that has been generated in the photodiode up to that point. Next, in S008, the timing generator 189 determines whether or not the elapsed time T up to the present time has reached the instruction time of exposure/charge accumulation in the exposure/accumulation/discharge timing. The indicated times for exposure and charge accumulation are time periods t1 to t1 ^* (602-1), t2 to t2 ^* (602-2), t3 to t3 ^* (602-3), . . . It indicates the time within each period from tn to tn ^* (602-n). If the current time is the instruction time for exposure and charge accumulation, the process proceeds to S009; otherwise, the process returns to S007.

In S009, exposure is performed in the time zone of the instruction time for exposure and charge accumulation, charges are generated in the PD 500, and the charges are transferred to the signal holding unit 507A and accumulated. In S010, the timing generation unit 189 determines based on the elapsed time T whether or not the shooting end time tn ^* has been reached. Information on the shooting end time tn ^* is included in the exposure/accumulation/ejection timing information and stored in the memory 190 . When the exposure/accumulation/ejection timing information is transmitted to the timing generator 189 in S005, the information of the shooting end time tn ^* is also transmitted. If it is determined that the shooting end time tn ^* has been reached, the process proceeds to S011, and if it is determined that the shooting end time tn ^* has not been reached, the process returns to S008. In S011, a process of outputting the signal charges accumulated in the signal holding unit 507A as an image signal to the outside through the FD area 508 is executed, and one shot of imaging is completed.

In the example shown in FIG. 4B, exposure/accumulation and discharge are repeated multiple times. However, after the focus lens 180 moves toward the target position X0 and reaches within the predetermined range (X1 or more and X2 or less), it does not go out of the predetermined range (the range less than X1 or the range exceeding X2). It is possible. In that case, the exposure/accumulation operation and the ejection operation may be performed once each.

The effect of this embodiment will be described with reference to a comparative example shown in FIG. FIG. 6A is a diagram showing vibration of the focus lens 180 in the optical axis direction, like FIG. 4A. FIG. 6B is a timing chart showing the driving sequence of the imaging element 184 of the comparative example. In the comparative example, the shooting operation is performed after the settling period. An example is shown in which the vibration of the focus lens 180 converges within a predetermined range from a point O7 after the settling time has elapsed from the stop time of the motor 186 indicated by a point O3. That is, exposure starts from point O7 onwards.

As shown in FIG. 6B, the settling time is set to the time until the focus lens 180 does not deviate from the predetermined range without starting charge accumulation even when the focus lens 180 reaches the predetermined range from the initial position. It is After the settling time has elapsed, the imaging element 184 starts accumulating signal charges in the PD 500 from time t1, and then transfers the signal charges to the signal holding unit 507A. The image signal based on the signal charges accumulated in the period (602-1) from time t1 to time t4 can be read out, and the image signal is output to the outside at time t5 when the transfer pulse φTX2(1) becomes high level. be done.

From a comparison between FIG. 4B and FIG. 6B, it can be seen that exposure can be started without waiting for the settling time to elapse in this embodiment. According to the present embodiment, it is possible to shorten the time from when the user performs an operation for instructing the start of imaging to when the imaging element starts exposure while suppressing image deterioration.

[Second embodiment]
Next, a second embodiment of the invention will be described. The image pickup apparatus of this embodiment includes a position detection section 187 (see FIG. 2) that detects the position of the focus lens 180 . For example, the position detection unit 187 detects the position to which the focus lens 180 is moved by the motor 186 with a sensor. The position detector 187 outputs a position detection signal to the system controller 178 . The system control unit 178 performs drive control of the focus lens 180 based on the acquired position detection signal. In addition, in this embodiment, by using the same reference numerals as those of the first embodiment, the detailed explanation thereof will be omitted, and mainly the differences will be explained. This method of omitting description is the same in the embodiments described later.

FIG. 7 is a flowchart for explaining the processing of this embodiment. In the present embodiment, an example of controlling the imaging device 184 based on the position information of the focus lens 180 acquired by the position detection unit 187 is shown. The processing from S101 to S103 is the same as the processing from S001 to S003 in FIG. 5, respectively, so detailed description is omitted.

At S104, the driving of the motor 186 is started in accordance with the lens drive speed and acceleration data determined at S103. In S105, immediately after the start of driving the motor 186, signal charges generated by photoelectric conversion in the PD 500 in the imaging device 184 are discharged.

In next S106, the system control unit 178 determines whether or not the detected position of the focus lens 180 is within a predetermined range. Specifically, referring to FIG. 4A, the predetermined range is a range of X1 or more and X2 or less. That is, the predetermined range for the focus lens position in the optical axis direction has a lower limit of X1 and an upper limit of X2. The system controller 178 determines whether the detected position of the focus lens 180 obtained from the position detector 187 is greater than or equal to X1 and less than or equal to X2. If the determination condition is satisfied, the process proceeds to S107, and if the determination condition is not satisfied, the process returns to S105.

In S107, the PD 500 starts exposure, and the generated signal charges are transferred to the signal holding unit 507A for accumulation. At this time, the system control unit 178 executes a process of storing the total exposure time performed multiple times in the memory 190, and starts counting the total exposure time. In next S108, the system control unit 178 determines whether or not the counted total exposure time is shorter than the exposure time corresponding to the shutter speed corresponding to the exposure amount determined in S102. If the total exposure time is shorter than the exposure time corresponding to the shutter speed, the process proceeds to S121, and if the determination condition is not satisfied, the process proceeds to S109.

In S121, the system control unit 178 determines whether the detected position acquired from the position detection unit 187 is less than X1 or exceeds X2. If it is determined that the detected position is less than X1 or exceeds X2, the process proceeds to S122, and if the determination condition is not satisfied, the process returns to S107.

In S122, since the detection position of the focus lens 180 is out of the predetermined range (range less than X1 or range over X2), accumulation of signal charges is terminated, and counting of the total exposure time is terminated. Then, the process returns to S105, and the signal charge generated by the PD 500 is discharged. The count value is added to the value stored in the memory 190 as the total exposure time and accumulated. After that, when the process of S107 is performed again, the total exposure time is restarted.

In S109, since the exposure and accumulation for the time corresponding to the shutter speed have been completed, the signal charge accumulated in the signal holding unit 507A is output as an image signal to the outside through the FD area 508, and one shot of photographing is performed. finish.

In this embodiment, accumulation and discharge of signal charges are performed based on detection position information of the focus lens 180 obtained from the position detection unit 187 . Therefore, even if the vibration waveform of the focus lens 180 is disturbed by some disturbance after the start of driving the motor 186, more accurate exposure can be performed when the position of the focus lens 180 is within a predetermined range.

[Third Embodiment]
Next, a third embodiment of the invention will be described. In this embodiment, the image sensor 184 is controlled by combining the elapsed time T and the detection position information of the focus lens 180 . As a result, even when the vibration waveform of the focus lens 180 is disturbed, more accurate exposure can be performed when the position of the focus lens 180 is within a predetermined range. Furthermore, the effect of reducing the time lag in a series of operations of the imaging element 184 can be obtained. The configuration of the imaging apparatus of this embodiment is the same as that of the second embodiment.

FIG. 8 is a flow chart for explaining the control of this embodiment. In this embodiment, the imaging element 184 is controlled using both the elapsed time T and the detected position information. The processing from S201 to S203 is the same as the processing from S001 to S003 in FIG. 5, respectively, so detailed description is omitted.

In S204, the system control unit 178 determines operation timings for exposure, accumulation, and ejection of the imaging device 184 based on the lens drive speed and acceleration data determined in S203. Although the basic processing is the same as that of S004 in FIG. 5, in this embodiment, unlike the first embodiment, in FIG. Start counting the elapsed time T. Therefore, t1=0, and the memory 190 stores predetermined exposure/accumulation/ejection timing information from t1 onwards to the shooting end time tn*. The system control unit 178 reads out these pieces of information from the memory 190 and uses them as necessary.

In S<b>205 , the system control unit 178 reads exposure/accumulation/ejection timing information from the memory 190 and transmits it to the timing generation unit 189 . At S206, the driving of the motor 186 is started. Immediately after the start of driving the motor 186 in S207, in the imaging element 184, signal charges generated by photoelectric conversion in the PD 500 are discharged.

Next, in S208, the system controller 178 determines whether or not the detected position obtained from the position detector 187 is greater than or equal to X1. If the detected position is greater than or equal to X1 for the first time, the process proceeds to S209, and if the detected position is less than X1, the process returns to S207.

In S209, since the position detected by the position detection unit 187 is within the predetermined range (X1 or more and X2 or less), counting of the elapsed time T is started. In S210, as in the first embodiment, the timing generation unit 189 determines from the elapsed time T whether or not the instruction time for charge accumulation in the exposure/accumulation/discharge timing has been reached. If the determination condition is satisfied, the process proceeds to S211, and if the determination condition is not satisfied, the process proceeds to S221. However, in S208, it is determined that the detected position is greater than or equal to X1, and in S210 immediately after starting counting the elapsed time T in S209, it is the instruction time for charge accumulation, so the process proceeds to S211.

In S211, the PD 500 starts exposure, the generated signal charges are transferred to the signal holding unit 507A, and an accumulation operation is performed. After this, the imaging element 184 is controlled based on the elapsed time T according to the exposure/accumulation/ejection timing information. Next, in S212, based on the elapsed time T, the system control unit 178 determines whether or not the current time has reached the shooting end time tn ^* . If it is determined that the shooting end time tn ^* has been reached, the process proceeds to S213, and if it is determined that the time has not been reached, the process returns to S210. If the process proceeds from S210 to S221, the signal charges generated in the PD 500 are discharged, and then the process returns to S210. In S213, the signal charge accumulated in the signal holding unit 507A is output as an image signal to the outside through the FD area 508, and one shot of imaging is completed.

In this embodiment, the elapsed time T is counted from the time when the detection position acquired by the position detection unit 187 first reaches the lower limit X1 of the predetermined range, and then the elapsed time T is counted according to the exposure/accumulation/ejection timing information. The imaging element 184 is controlled according to T. Therefore, even if there is variation in the time taken for the focus lens 180 to first reach the predetermined range from the initial position before the motor 186 is driven, the signal when the position of the focus lens 180 is within the predetermined range can be obtained more accurately. It can store charge.

In addition, in the case of the second embodiment, the system control unit 178 always determines whether the detection position is within the predetermined range or outside the predetermined range. have a nature. On the other hand, in this embodiment, after the position of the focus lens 180 first reaches within the predetermined range, the imaging element 184 is controlled according to the exposure/accumulation/ejection timing information, so the time lag can be reduced.

[Fourth Embodiment]
Next, a fourth embodiment of the invention will be described. In the case of synthesizing a plurality of images obtained by performing split exposures to generate one image, the longer the interval between split exposures, the greater the amount of movement of the subject between them. A problem arises in that the moving subject appears discretely in the synthesized image, degrading the image quality. In the following embodiments, an imaging device capable of suppressing degradation of image quality will be described.

FIG. 9 is a schematic diagram showing a cross section of the imaging device 11. As shown in FIG. An imaging device 11 includes a lens 12 and an imaging element 13 , and light from a subject enters the imaging element 13 through the lens 12 along an imaging optical axis 10 . The image processing unit 14 performs predetermined image processing on the imaging signal acquired by the imaging element 13 .

The CPU 15 supervises control of the imaging device 11 . For example, the CPU 15 controls charge accumulation in the imaging device 13 . The operation unit 16 receives a user's instruction for photographing timing, an operation for setting an exposure time, and the like, and outputs an operation instruction signal to the CPU 15 . The CPU 15 controls charge accumulation by the image pickup device 13 based on the brightness of the subject detected by the image pickup device 13 before photographing and the set exposure time set using the operation unit 16 . Accumulation control will be described with reference to FIG.

FIG. 10A is a simplified circuit diagram of a photoelectric conversion portion included in a pixel portion. The imaging device 13 has a plurality of photoelectric conversion units arranged in a two-dimensional array, one of which is shown in FIG. 10(A). The PD 21 generates charges corresponding to the light from the subject. The charge generated by the PD 21 is transferred to the capacitor 22 by the storage switch 23 . The charges transferred to the capacitor 22 are input to the amplifier circuit 25 via the transfer switch 24 . The signal amplified by the amplifier circuit 25 is output to the image processing section 14 .

The reset switch 26 resets the charge accumulated in the PD 21 at a predetermined timing to prepare for the next imaging. Switching timings of the reset switch 26, the storage switch 23, and the transfer switch 24 will be described with reference to FIG. 10B.

FIG. 10B is a timing chart showing the exposure state of the photodiode and the state of each switch. FIG. 10B shows the direction of time passage from left to right, and shows the states of the PD 21 divided exposure, the reset switch 26, the accumulation switch 23, and the transfer switch 24 in order from the top.

The set exposure time at the time of shooting is set by the operation unit 16 according to the user's instruction, but if there is a gap between the set exposure time and the appropriate exposure time obtained from the brightness of the subject detected by the image sensor 13, adjustment is required. be. Below, the proper exposure time corresponding to the set exposure time is defined as the actual exposure time. For example, assume that the set exposure time is set to 1 second with the intention of expressing a dynamic flow when photographing a waterfall. If the actual exposure time calculated from the brightness of the subject is 0.2 seconds, the amount of light must be reduced to 1/5.

The CPU 15 that controls the photoelectric conversion section of the image sensor 13 intermittently performs divided exposures in short seconds so that a total of 0.2 seconds corresponding to the actual exposure time is obtained in 1 second. The intermittently divided exposure time is called a divided exposure time, and in the example of FIG. 10B, the width of the pulse 31 is 0.05 seconds.

Reset switch 26 resets the charge of PD 21 at the timing indicated by pulse 32 . After 0.05 seconds, which corresponds to the split exposure time, the charges accumulated in the PD 21 are transferred to the capacitor 22 via the accumulation switch 23 . According to pulse 33, storage switch 23 is switched. The above operation is repeated four times.

The charge in the capacitor 22 increases each time the storage switch 23 is turned on, and the charge storage of the PD 21 is completed four times. When all the charges are transferred to the capacitor 22, the capacitor 22 stores four times of 0.05 seconds, that is, charges corresponding to the actual exposure time of 0.2 seconds. Since the signal charges corresponding to the actual exposure time of 0.2 seconds are acquired over the set exposure time of 1 second, the movement of the object during that time is reflected in the image signal.

The transfer switch 24 is turned on at the timing when the capacitor 22 stores electric charge corresponding to the actual exposure time, as indicated by the pulse 34 . The amplifier circuit 25 amplifies the signal corresponding to the charge and outputs it to the image processing section 14 . The CPU 15 controls the reset switch 26, the storage switch 23, and the transfer switch 24 to change the number of divisions of the exposure and the time and timing of each divided exposure. The difference between the set exposure time and the actual exposure time can be dealt with by controlling the photoelectric conversion unit. That is, shooting is performed with an actual exposure time that is shorter than the set exposure time.

FIG. 11 is an explanatory diagram of an image captured based on the control described with reference to FIG. 10B. The horizontal direction (horizontal direction in the figure) corresponds to the direction of shooting time, and the vertical direction (vertical direction in the figure) corresponds to the vertical direction of the shooting screen. Although FIG. 10B illustrates the switching timing when performing four divided exposures within the set exposure time, FIG. 11 illustrates an example of performing two divided exposures for easier understanding. The set exposure time 41 includes divided exposure times 42a and 42d. A non-exposure time 43a is between the split exposure times 42a and 42d, and a non-exposure time 43b is shown to the right of the split exposure time 42d.

The PD groups in all the photoelectric conversion units convert the light from the object into charges and accumulate them (charge accumulation) during the divided exposure times 42a and 42d. Since the non-exposure time 43a is sandwiched between the split exposure times 42a and 42d, the movement of the moving subject appears discretely on the screen. Therefore, in this embodiment, the CPU 15 controls the photoelectric conversion units differently in the vertical direction of the screen, and performs control to shift the phase of the charge accumulation timing of the PD 21 in adjacent rows. A specific description will be given with reference to FIG.

FIG. 12 shows an example in which the phases of the charge accumulation timings of the PDs 21 are shifted in adjacent rows. This example shows the relationship between split exposure times 42a and 42b, split exposure times 42c and 42d, and non-exposure times 43a, 43b, and 43c. As can be seen from the comparison with FIG. 11, the CPU 15 controls the image sensor 13 so that the phase relationship between the split exposure times 42a and 42b and the phase relationship between the split exposure times 42c and 42d are opposite in phase. When the user views the captured image, the interval of the non-exposure time is halved compared to that in FIG. 11, so discrete movements of the subject image are no longer noticeable, and deterioration of image quality can be suppressed.

A case where the actual exposure time is lengthened will now be described. In FIG. 12, the split exposure time 42a is in the left time region 51, the split exposure times 42b and 42c are in the middle time region 52, and the split exposure time 42d is in the right time region 53. FIG. A time region 51 is a region on the exposure start side, and a time region 53 is a region on the exposure end side. As the actual exposure time becomes longer, the split exposure times 42a and 42c extend toward the right side of the paper. This corresponds to delaying the end timing of the split exposure by the time t. On the other hand, the divided exposure time 42d exceeds the set exposure time 41 if it is extended to the right side of the paper. Therefore, as the actual exposure time becomes longer, the divided exposure time 42d extends leftward on the paper surface. The same applies to the split exposure time 42b. This corresponds to advancing the start timing of the split exposure by the time t.

FIG. 13 exemplifies a photographed image when the above operation is performed. When the actual exposure time becomes longer, the divided exposure time 42a in the left time region 61L and the divided exposure time 42c in the right time region 61R are extended to the right. The divided exposure time 42b in the left time region 61L and the divided exposure time 42d in the right time region 61R are extended to the left.

The longer the actual exposure time, the shorter the non-exposure time, but the exposure timing overlaps between the time regions 61L and 61R in adjacent rows. A subject exposed at the timing when overlap occurs appears to have a higher density on the screen than a subject exposed at the timing when overlap does not occur. In the present embodiment, further measures are taken to prevent the movement of the subject from appearing discretely in the captured image. A specific example will be described with reference to FIG.

FIG. 14 shows divided exposure times 42a and 42b in the set exposure time 41 and non-exposure time 43a between them. The CPU 15 performs control to align and synchronize the charge accumulation timings of the PDs 21, which are shifted in adjacent rows in FIGS. The difference from FIG. 11 is that because the divided exposure times 42a and 42b are longer, the ratio of the non-exposure time 43a to the set exposure time 41 is smaller, and the moving subject is no longer captured discretely. It is a point. In the case of FIG. 13, since the density is high in the portions where the exposure timings overlap in adjacent rows, the non-exposure time 43a is the time between the time regions 61L and 61R where the exposure timings overlap. On the other hand, in FIG. 14, the non-exposure time 43a can be shortened by synchronizing the exposure timings. Therefore, since the overlap of the exposure timings is not partial, the density change of the object is not conspicuous.

In the examples of FIGS. 11 to 14, the CPU 15 controls each divided exposure for each line, but it may also control divided exposure for each zone of several lines. In that case, the first control for different charge accumulation timings in adjacent rows (boundaries of both zones) and the second control for synchronizing the charge accumulation timings are determined depending on the relationship between the actual exposure time and the set exposure time. It is determined. In this manner, the CPU 15 switches the imaging element 13 between the first control mode and the second control mode based on the ratio of the actual exposure time to the set exposure time.

The control of this embodiment will be described with reference to FIG. The processing shown in the flowchart of FIG. 15 is started by an instruction for a photographing preparation operation of the imaging device 11 (for example, half-pressing of the release button). In S<b>81 , the CPU 15 acquires information on the set exposure time from the operation unit 16 and the brightness of the subject from the image sensor 13 . The CPU 15 calculates the actual exposure time based on the subject brightness information from the imaging device 13 .

In S82, the CPU 15 determines whether it is necessary to shift the phase of the exposure timing for each adjacent row based on the relationship between the set exposure time and the actual exposure time. For example, the value of the ratio between the actual exposure time and the set exposure time is compared with a predetermined threshold value (1/3). If the value of the ratio is less than the threshold, the process proceeds to S83, and if it is equal to or greater than the threshold, the process proceeds to S84. In S83, the CPU 15 is set to perform the first control (opposite phase control of the exposure timing in the adjacent row) as shown in FIG. In S84, the CPU 15 is set to perform the second control (in-phase control of exposure timings in adjacent rows) as shown in FIG.

After S83 and S84, the CPU 15 determines whether to start exposure in S85. The determination process of S<b>85 is repeatedly executed until an instruction to start photographing is given from the operation unit 16 . If a shooting start instruction is input from the operation unit 16, the process proceeds to S86. In S86, the CPU 15 performs divided exposure of the image sensor 13 according to the control set in S83 or S84, and returns the process to S81.

In this embodiment, in controlling the image sensor 13 having a plurality of photoelectric conversion units, the photoelectric conversion units are intermittently controlled within the set exposure time to provide a plurality of divided exposure times. Regarding the divided exposure time of adjacent rows (or adjacent zones), there are two types of control: the first control for differentiating the exposure timing for each adjacent row (or adjacent zone), and the second control for aligning the exposure timing of adjacent rows (or adjacent zones). done as appropriate. Each control is set or changed based on the relationship between the set exposure time and the actual exposure time (total of multiple divided exposure times). According to this embodiment, it is possible to provide an imaging device capable of suppressing deterioration in image quality.

[Fifth embodiment]
Next, the differences between the fifth embodiment of the present invention and the fourth embodiment will be described. FIG. 16 corresponds to FIG. 12, and differs from FIG. 12 in that a non-exposure time 43d is provided at the end of the set exposure time 41. FIG. The set exposure time 41 includes divided exposure times 42a to 42d and non-exposure times 43a to 43d.

A case of lengthening the actual exposure time in the time arrangement of FIG. 16 will be described. In this case, each divided exposure time 42a, 42b, 42c, 42d extends rightward on the paper. This corresponds to delaying each exposure end timing by a predetermined time t. In the description of FIG. 12, since the divided exposure time 42d in the time region 53 is positioned at the right end within the set exposure time 41, the exposure end timing could not be delayed. On the other hand, in FIG. 16, since the non-exposure period 43d is provided at the end (right end) within the set exposure time 41, the exposure end timing can be delayed.

FIG. 17 is an explanatory diagram of overlap of exposure timings in adjacent rows. A case where the ratio of the actual exposure time to the set exposure time 41 is 1/2 is shown. As indicated by the checkered pattern in FIG. 17, the right end position of the divided exposure time 42a is the same as the left end position of the divided exposure time 42b in the horizontal direction, and the right end position of the divided exposure time 42b is the same as the left end position of the divided exposure time 42c. are the same. The right end position of the divided exposure time 42c is the same as the left end position of the divided exposure time 42d. Overlapping of exposure timings in adjacent rows does not occur until the actual exposure time becomes half the set exposure time 41 .

FIG. 18 shows the case where the actual exposure time is further extended. Between the divided exposure time 42a and the divided exposure time 42b in the left time region 110L, the exposure timings of adjacent rows overlap. Also, between the divided exposure time 42c and the divided exposure time 42d in the right time region 110R, the exposure timings of the adjacent rows overlap. The reason for this is that when the split exposure time 42d reaches the end of the set exposure time 41, the split exposure time is adjusted by advancing the exposure start timing by the time t with respect to the split exposure times 42b and 42d of that row (or zone). This is because processing is performed. That is, the divided exposure time extends to the left of the paper. In this case, the movement of the subject is likely to appear discrete.

Therefore, in this embodiment, the following control is performed. A specific example will be described with reference to FIG.
• Control for divided exposure time 42b Control is performed to delay the exposure start timing and the exposure end timing shown in FIG. 18 by the time τ.
Control for split exposure time 42c Control is performed to advance the exposure start timing and the exposure end timing shown in FIG. 18 by the time τ.
In this case, exposure timings overlap in three time regions 120 . However, since the width of each time region 120 is smaller than that of the time regions 110L and 110R shown in FIG. 18, the motion of the subject is less likely to appear discrete.

In the fourth embodiment, when the actual exposure time becomes long, the CPU 15 performs control to align the timings of the divided exposure times in adjacent rows (or adjacent zones). On the other hand, in the present embodiment, when the actual exposure time becomes longer, control is performed to shift the timing of the divided exposure time for each row (or adjacent zone). In this embodiment, even if the actual exposure time is long, there is no exposure timing overlap until the split exposure time shown in FIG. 17 is reached, so there is no need to change split exposure control under many shooting conditions.

The CPU 15 controls the imaging device 13 to change the exposure timing for each adjacent row, and phase shift control for shifting the exposure timing for each adjacent row. Each control is selected based on the relationship between the set exposure time and the actual exposure time.

The control of this embodiment will be described with reference to the flowchart of FIG. S130 to S132, which are different from FIG. 15, will be described. After S81, in S130, the CPU 15 determines whether it is necessary to shift the phase of the exposure timing for each adjacent row based on the relationship between the set exposure time and the actual exposure time. For example, the value of the ratio between the actual exposure time and the set exposure time is compared with a predetermined threshold value (1/2). If the value of the ratio is less than the threshold, the process proceeds to S131, and if it is equal to or greater than the threshold, the process proceeds to S132.

In S131, the CPU 15 sets the exposure timings of the adjacent rows to be opposite phase control as shown in FIGS. In S132, the CPU 15 is set to perform phase shift control of exposure timings in adjacent rows as shown in FIG. In other words, the timing of the divided exposure time 42b is delayed and the timing of the divided exposure time 42c is advanced. After S131 or S132, the process proceeds to S85.

In the present embodiment, with respect to the divided exposure time of adjacent rows (or adjacent zones), control to vary the exposure timing for each adjacent row (or adjacent zone) and control to shift the exposure timing for each adjacent row (or adjacent zone) are performed. done. Each control is set or changed based on the relationship between the set exposure time and the actual exposure time. According to this embodiment, it is possible to provide an imaging device capable of suppressing deterioration in image quality.

[Sixth Embodiment]
Next, the differences between the sixth embodiment of the present invention and the fourth embodiment will be described. FIG. 21 corresponds to FIG. 12, and differs from FIG. 12 in that the split exposure times 42a and 42e at the start and end sides of the set exposure time 41 are shorter than the other split exposure times 42b-d. The left end of the split exposure time 42a is the start point of the set exposure time 41, and the right end of the split exposure time 42e is the end point of the set exposure time 41. FIG. The split exposure times 42a and 42e are set to half the split exposure times 42b, 42c and 42d.

A case of lengthening the actual exposure time in the time arrangement of FIG. 21 will be described with reference to FIG. In this case, the following controls are performed. Time t/2 corresponds to the length of divided exposure times 42a and 42e in FIG.
• Control over the split exposure time 42a Control is performed to delay the exposure end timing by time t/2. That is, the amount of extension of the split exposure time is set to t/2.
Control over split exposure times 42b, 42c, and 42d Control is performed to advance the exposure start timing by time t/2 and delay the exposure end timing by time t/2. That is, the amount of extension of the split exposure time is set to t.
• Control for split exposure time 42e Control is performed to advance the exposure start timing by time t/2. That is, the amount of extension of the split exposure time is set to t/2.

Through the above control, the split exposure times 42a and 42e are lengthened by t/2, and the split exposure times 42b, 42c and 42d are lengthened by t. Controlling the timing of the start and end of the split exposure results in the total actual exposure time of rows or zones with split exposure times 42a, 42c, 42e and the total real exposure time of rows or zones with split exposure times 42b, 42d. can always be the same length.

In this embodiment, by controlling the amount of extension of the divided exposure time according to the arrangement of the divided exposure time with respect to the set exposure time, the overlapping amount of the exposure timings can be made constant even if the actual exposure time increases. Since the exposure timings of adjacent rows (or adjacent zones) overlap in many places, the interval between them is narrowed and the movement of the subject does not appear to be discrete.

The CPU 15 controls and sets the image sensor 13 as follows.
- Control to vary the exposure timing for each adjacent row (or adjacent zone).
・Setting of split exposure time.
The split exposure times provided at the start and end timings of the set exposure time are set to approximately half the split exposure times provided at times other than the start and end timings of the set exposure time.
・Set the amount of extension of split exposure time.
The amount of extension of the divided exposure time provided at the start and end timing of the set exposure time is set to approximately half the amount of extension of the divided exposure time provided at timings other than the start and end timing of the set exposure time.

In this embodiment, it is possible to provide an imaging apparatus capable of suppressing deterioration in image quality by setting divided exposure times provided at the start and end timings of the set exposure time and by setting the amount of extension of each divided exposure time. .

178 system control unit 180 focus lens 184 image sensor 186 motor 187 position detection unit 189 timing generation unit 500 photodiode 507A signal holding unit

Claims (14)

an imaging means comprising a pixel portion having a photoelectric conversion portion and a signal holding portion;
Driving means for moving a lens for focus adjustment in the optical axis direction and control means for controlling the imaging means,
The control means sets a range based on a target position of the lens, and transfers signal charges generated in the photoelectric conversion section to the signal holding section when the lens is positioned within the range. The signal charges are discharged when the lens is positioned outside the range, and the signal charges generated in the photoelectric conversion section during the imaging period are transferred to and accumulated in the signal holding section a plurality of times to generate an image signal. An imaging device characterized by performing control to After the lens has moved toward the target position and reached the range, the control means converts the signal charges generated in the photoelectric conversion unit when the lens is positioned within the range into the signal holding unit. 2. The image pickup apparatus according to claim 1, wherein control for transferring the signal charge to the unit and control for discharging the signal charge when the lens is positioned outside the range are repeated. Data of timing for starting exposure in the photoelectric conversion unit when the lens is positioned within the range and transferring and accumulating generated signal charges to the signal holding unit, and data of timing when the lens is positioned outside the range storage means for storing timing data for discharging the signal charge when the signal charge is discharged;
3. The imaging apparatus according to claim 1, wherein said control means controls the operation of said imaging means using data read from said storage means. comprising detection means for detecting the position of the lens,
The control means transfers signal charges generated in the photoelectric conversion section to the signal holding section when the position of the lens detected by the detection means is within the range, and 3. The imaging apparatus according to claim 1, wherein control is performed to discharge the signal charge when the position of the lens is out of the range. detection means for detecting the position of the lens;
When the position of the lens is within the range, exposure in the photoelectric conversion unit is started, and data of timing for transferring and accumulating the generated signal charge to the signal holding unit, and when the lens is outside the range. storage means for storing timing data for discharging the signal charge when positioned;
2. After the position of the lens detected by the detection means reaches the range, the control means controls the operation of the imaging means using the data read out from the storage means. 3. The imaging device according to claim 2. Storage means for storing data on the driving speed and acceleration of the lens,
3. The control device according to claim 1, wherein the control device determines operation timings of exposure, accumulation, and ejection in the imaging device from data of driving speed and acceleration acquired from the storage device. Imaging device. When performing split exposure by intermittently controlling the photoelectric conversion unit, the control means sets a plurality of split exposure times within the set exposure time, and performs split exposure in adjacent rows or zones in the captured image. 7. The imaging apparatus according to any one of claims 1 to 6, wherein control is performed to change the exposure timing in terms of time. 8. The control unit according to claim 7, wherein the control means performs a first control that makes the exposure timings different for each of the adjacent rows or zones, and a second control that makes the exposure timings of the adjacent rows or zones uniform. imaging device. 8. The control unit according to claim 7, wherein the control means performs a first control of varying the exposure timing for each of the adjacent rows or zones, and a second control of shifting the phase of the exposure timing for each of the adjacent rows. imaging device. 10. The imaging apparatus according to claim 8, wherein, in the first control, the control means performs reverse-phase control of exposure timing for each of the adjacent rows or zones. The control means performs the first control when the ratio of the actual exposure time, which is the sum of the plurality of divided exposure times, and the set exposure time is smaller than a threshold, and the ratio is equal to or greater than the threshold. 11. The imaging apparatus according to any one of claims 8 to 10, wherein the second control is performed when . The control means makes the first divided exposure time provided at the start and end timings of the set exposure time shorter than the second divided exposure time provided at timings other than the start and end timing of the set exposure time. 12. The imaging apparatus according to any one of claims 7 to 11, characterized in that: The control means sets the first split exposure time to half the second split exposure time, and sets the extension amount of the first split exposure time to half the extension amount of the second split exposure time. 13. The imaging device according to claim 12, characterized in that: A control method executed in an imaging device in which a pixel portion of an imaging means has a photoelectric conversion portion and a signal holding portion,
a first step of controlling a driving means for moving a lens for focus adjustment in the optical axis direction;
a second step of controlling the imaging means;
In the first step, a range based on the target position of the lens is set,
In the second step, when the lens is positioned within the range, the signal charge generated in the photoelectric conversion section is transferred to the signal holding section, and when the lens is positioned outside the range, the signal charge is transferred to the signal holding section. Control is performed to discharge electric charges, and control is performed to generate an image signal by transferring and accumulating signal charges generated in the photoelectric conversion unit in the signal holding unit over a plurality of times during an imaging period. A control method for an image pickup apparatus.

Images