JPH07284008A - Image pickup device - Google Patents

Abstract

PURPOSE:To provide an image pickup device capable of performing precise exposure control at the time of picking up still images. CONSTITUTION:This image pickup device is capable of picking up the still images and when a shutter button 110 is pushed, an exposure by the exposure control at present is calculated in a control circuit 107. Then, the exposure at the time of picking up the still images is decided based on a calculated result obtained at the time of picking up moving images and the exposure control is performed in a mechanical shutter control circuit 108 and an image pickup element driving circuit 109. The a precise exposure control is performed at the time of picking up the still images and the still images of high image quality are picked up.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image pickup device such as a video camera and, more particularly, to exposure control when a video signal of a still image is generated.

[0002]

2. Description of the Related Art Video cameras have been developed with various functions accompanying the digitization of signal processing.
Since it can easily output a digital video signal, it is attracting attention as a video input means such as a computer. The video handled by a computer is generally a still image, and in order to obtain a video signal of the still image, at present, among the moving images output from the camera integrated VTR using a consumer integrated camera VTR. The video signal for any one field or frame is recorded in a memory or the like. The video signal recorded in the memory or the like is input to the computer as a still image. Japanese Patent Laid-Open No. 2-288679 describes a technique of outputting a still image with proper exposure in a video camera.

[0003]

However, the above image input method is not a preferable method because of the following problems.

(1) To make an automatic control system compatible with still images ... A general video camera controls exposure using a video signal. That is, a detector for detecting the illuminance of the subject is not separately provided, but is detected from the video signal and fed back to each control unit.
However, even if it is detected from the video signal of a still image, it cannot be fed back to the detected still image.

(2) Allowing a still image of a frame to be generated using a general image pickup device ... A general image pickup device is a destructive read-out in which a pixel signal can be read out only once, and moreover, it is vertical. This is a pixel mixing method in which signals of two pixels adjacent in the direction are mixed and read out. If signal processing is performed in the above-described reading method, a still image with a resolution matching the number of pixels cannot be generated.

It is an object of the present invention to solve these problems and capture a full frame still image with a normal video camera (iris and signal processing).

[0007]

In order to solve the above-mentioned problem (1), the present invention provides a light quantity limiting means for blocking a part of incident light, photoelectric conversion of incident light for each pixel, and photoelectric conversion by the pixel. A solid-state imaging device having a shutter function for sweeping out the converted charges at an arbitrary time, signal processing means for outputting a signal photoelectrically converted by the solid-state imaging device as a video signal,
And adjusting the exposure amount by controlling the shutter function of the light amount limiting unit and the solid-state image pickup device, and at the time of still image shooting, the light amount limiting unit and the shutter at the exposure amount specified at the time of moving image shooting before that. It has an exposure control means for controlling the exposure of the function.

In order to solve the above-mentioned problem (2), in the present invention, the signal processing means outputs the pixel signals independently when the solid-state image pickup device outputs the pixel signals. The video signal is generated by different signal processing depending on the time.

[0009]

According to the means for solving the above problem (1),
The detection result at the time of capturing a moving image is stored, and a still image is generated based on the detection result.

According to the means for solving the above problem (2), when a still image is picked up, the driving method of the image pickup device is changed so that the pixel signals are read out without being mixed, and the still image is read by the signal processing circuit. When the video signal of is input, the contents of the signal processing are switched to those for still images.

[0011]

The present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of an image pickup apparatus according to a first embodiment of the present invention. In the figure, 101 is a lens,
102 is a mechanical shutter, 103 is an image sensor, 104
Is an amplifier, 105 is an A / D converter, 106 is a video signal processing circuit, 107 is a camera control circuit, and 108 is
A mechanical shutter control circuit, 109 is an image sensor drive circuit,
Reference numeral 110 is a shutter button. A specific example of the image sensor 103 is shown in FIG. In FIG. 2, 201 is a photodiode, 202 is a vertical CCD, and 203 is a horizontal CCD.
And gr, mg, cy, and ye are photodiode 2
01 is a color filter arranged on each surface, gr is green, mg is magenta, cy is cyan, and ye is yellow.
Indicates that it is a color filter. A photo diode provided with such a color filter is generally called a pixel. The light input through the lens 101 is input to the image sensor 103 through the mechanical shutter 102 whose aperture value F is controlled by the mechanical shutter control circuit 108, photoelectrically converted by the photo diode 201 arranged on the surface of the image sensor 103, and vertically converted. Pixels are mixed in CCD202, and horizontal C
It is output via the CD 203. The output signal of the image sensor 103 is amplified by the amplifier 104, and the A / D converter 10
Video signal processing circuit 10 converted into a digital signal at 5
6 is input. The video signal processing circuit 106 converts the input signal into a video signal such as NTSC and outputs the video signal, and outputs the brightness information of the subject to the camera control circuit 107. The camera control circuit 107 controls the mechanical shutter control circuit 108 so that the output of the video signal processing circuit 106 reaches a desired luminance level based on the luminance information of the subject, changes the aperture value of the mechanical shutter 102, and also needs it. The image sensor driving circuit 109 is controlled in accordance with the above, and the electronic shutter speed of the image sensor 103 is controlled.

Next, the electronic shutter will be briefly described. FIG. 3 is a diagram schematically showing the potential of the image sensor 103. In the figure, 301 is the image sensor 1.
The charge accumulated in 03, 302 is the read gate, and 3
Reference numeral 03 is a substrate voltage, 304 is a well, and 305 is a channel stopper. The charges photoelectrically converted by the photo diode 201 are read out by the gate 602 and the well.
During 604 it is stored as shown. Image sensor 10
When the charge sweep pulse is supplied from the image pickup element drive circuit 109 to 3, the potential of the substrate voltage 303 is lowered. Then, as shown in FIG. 4, the potential of the well 304 is lowered in the form of being drawn into the substrate voltage 303. Then, the charge 301 is swept to the portion of the substrate voltage 303. The channel stopper 305 is for preventing leakage of charges from the vertical CCD 202 corresponding to the adjacent pixel.

In this structure, the shutter button 110
When is pressed, a shutter-close control signal is input from the camera control circuit 107 to the mechanical shutter control circuit 109, and the mechanical shutter control circuit 109 brings the mechanical shutter 102 into the closed state after a predetermined time. By the time the mechanical shutter 102 is closed, the image sensor 1
The light input to the image sensor 03 is input to the image sensor 10 as in the above operation.
Photoelectric conversion is carried out by the photo diode 201 arranged in No. 3, and the mechanical shutter 102 is in the vertical CC while the mechanical shutter 102 is in the close state.
The data is transferred to the horizontal CCD 203 via D202, converted in voltage in synchronization with the horizontal scanning pulse supplied from the image pickup element drive circuit 109, and output. At this time, the image sensor 10
3 is a so-called destructive read in which no signal remains in the photo diode 201 when the signal is read once from the photo diode 201, so that the pixel information is read when the pixel mixed read is a general read method. Will be lost.

The pixel mixed readout will be described below. The image sensor 103 mixes and reads two pixel signals that are vertically adjacent to each other until the shutter button 110 is pressed, as described in Japanese Patent Laid-Open No. 63-114487, so-called pixel mixing method. Read out.

FIG. 5 shows timing charts of vertical transfer pulses and pixel charge transfer in the vertical CCD 202 at the time of pixel mixed reading. In the figure, when the ternary pulse of the vertical transfer pulse 1 becomes high level, the ternary pulse of the vertical transfer pulse 3 becomes high level from the photodiode 201 in the rows gr and mg.
Signal charges are transferred from the photodiodes 201 in the rows y and ye to the vertical CCDs 202, respectively. Vertical CCD 20
As shown in FIG. 5, the signal charge transferred to the second vertical CC
Mixed in D202, transferred to horizontal CCD203,
It is output from the image sensor 103.

However, if the above-described pixel mixture reading is performed during still image pickup, it is not possible to obtain a resolution commensurate with the number of pixels in the vertical direction of the image pickup device 103. Therefore, during still image pickup, the following independent reading is performed. Do. FIG. 6 shows a timing chart of the vertical transfer pulse at the time of independent reading and the transfer of the signal charge in the vertical CCD 202. As shown in FIG. 6, the cycle in which the ternary pulse of the vertical transfer pulse 1 and the ternary pulse of the vertical transfer pulse 3 becomes high level is every other field as shown in FIG. Therefore, in the field where the ternary pulse of the vertical transfer pulse 1 becomes high level, the photodiode of the gr and mg rows is
The signal charge is transferred to the vertical CCD 202 only from the mode 201, and the ternary pulse of the vertical transfer pulse 3 becomes high level in the next 1 field, so that the vertical charge is generated only from the photo diode 201 in the rows cy and mg. The signal charge is transferred to the CCD 202. Since the signal charges transferred to the vertical CCD 202 are all transferred to the horizontal CCD 203 in one field period, the signal charges of the adjacent photodiodes 201 are mixed as in the above-mentioned pixel mixing read method. In this case, one signal can be obtained for one photodiode. Hereinafter, the signal charges transferred to the horizontal CCD 203 are output from the image sensor 103 in synchronization with the horizontal scanning pulse supplied from the drive circuit 105. The output signal of the image sensor 103 is amplified by the amplifier 104, converted into a digital signal by the A / D converter 105, and input to the video signal processing circuit 106. The video signal processing circuit 106 converts the input signal into a video signal and outputs it. However, when performing the above independent reading,
The exposure amount of the above-mentioned gr and mg line photodiodes, cy,
In order to equalize the exposure amount of the photo diode in the row of yes, the mechanical shutter 102 must be in the fully closed state from the start of the exposure for still image capturing to at least the reading of the above signals. . further,
The exposure amount for the image pickup element 103 is set to the image pickup element 103 immediately after the signal charge photoelectrically converted by the photodiode 201 included in the image pickup element 103 in the front field is transferred to the vertical CCD 202 until the mechanical shutter 102 is fully closed.
Is the amount of light incident on.

FIG. 7 is a graph showing the amount of exposure of the image sensor 103 with respect to the aperture value of the mechanical shutter 102.
In the exposure control of the video camera of this embodiment, the same operation as that of a normal video camera is performed until the shutter button 110 is pressed. That is, the image sensor 1 for one field period
The charge accumulated in 03 is read every field, the exposure amount is calculated from the luminance signal generated by the signal processing circuit, and the mechanical shutter control circuit 109 controls the diaphragm of the mechanical shutter 102 so that the exposure amount becomes a predetermined exposure amount. When the electronic shutter is not used, the exposure of the image sensor 103 is performed by the photodiode 2
Time t1 when electric charge is transferred from 01 to the vertical CCD 202
Since each time starts from t4 to t4, if the shutter button 110 is pressed between times t3 and t4, the time t
At 4, exposure for generating a still image is started. At this time,
It is assumed that the area (exposure amount) indicated by A is an appropriate exposure amount for the subject currently being imaged. In order to obtain an appropriate exposure amount at the time of capturing a still image, the mechanical shutter 102 is operated so that the area indicated by B, which is the exposure amount in the period from time t4 to t5, becomes equal to the area indicated by A. An appropriate amount of exposure can be obtained even during image pickup.

Next, a second embodiment of the present invention will be described with reference to the drawings.

In the image pickup apparatus shown in FIG. 1 in the above-mentioned first embodiment, the noise component in the signal at the time of picking up a moving image is generated every time
Each phase has a different phase and is smoothed by the human eye,
The noise component in the signal was not very noticeable. However, in the case of a still image, since the smoothing is not performed, it is necessary to improve the S / N when capturing a still image as compared with a conventional image capturing device that captures a moving image.

Means for improving the S / N will be described below with reference to FIG. In the figure, the charge photoelectrically converted by the photo diode 201 is read by the read gate 302 and we.
It is stored as shown in FIG. At the time of reading a moving image, the potential of the read gate 302 decreases due to the high level of the ternary pulse of the vertical transfer pulses 1 and 3 once per field, and the charge 301
Are transferred to the vertical CCD 202. At this time, the potential of the read gate shown in FIG.
If the value pulse is lowered by the high level, the potential of the read gate of the vertically adjacent pixel is lowered by the high level of the ternary pulse of the vertical transfer pulse 3. The charges 301 read by the above method are mixed in the vertical CCD 202 with the charges photoelectrically converted by the photodiodes which are adjacent to each other above or below. At the time of capturing a still image, only the ternary pulse of the vertical transfer pulse 1 is set to a high level in the first field at which reading is started, and only the ternary pulse of the vertical transfer pulse 3 is set in the second field. By setting it to a high level, the charge 301 is read out without performing the pixel mixing. At this time,
As long as the electric charge 601 does not overflow between the readout gate 602 and the well 604, even if the electric charge 301 is stored in one pixel in a larger amount than in the case of capturing a moving image, the vertical CCD 2
02 and the horizontal CCD 203 can transfer charges. S / N is improved by accumulating a large amount of charges in the image sensor 103 based on the above method.

Next, a third embodiment of the present invention will be described with reference to the drawings.

The configuration of the image pickup apparatus according to the third embodiment of the present invention is the same as that of the first embodiment described above, and will be described with reference to FIG. The description of the parts common to the first embodiment will be omitted. As shown in the above embodiment, in the case of capturing a still image, it is better that S /
N is advantageous. In the following, the exposure control during still image capturing will be described assuming that the amount of charge accumulated in the image sensor 103 is 1.5 times that during moving image capturing.

FIG. 8 shows the mechanical shutter 1 in this embodiment.
FIG. 3 is a diagram showing the exposure amount to the image sensor 103 and the charge transfer timing from the photo diode 201 to the vertical CCD 202 with respect to the aperture value of 02. In the above-mentioned image pickup apparatus, the exposure control similar to that of a general video camera is performed as described in the first embodiment before starting the still image pickup operation. Here, for the sake of simplicity, the moving image capturing time is shown only for three fields, but the length of the moving image capturing time is an arbitrary length until the exposure control is sufficiently stabilized, and then the shutter button 110. Is the time until is pressed. If the shutter button 110 is pressed at the time indicated by ts in FIG. 8 after the exposure control of the moving image is stabilized, a shutter close control signal is input from the camera control circuit 107 to the mechanical shutter control circuit 109 and the shutter is released. The control circuit 108 causes the mechanical shutter 102 to start the closing operation at the beginning of the next field, that is, at time t4. That is, exposure for capturing a still image starts at time t4. At this time, it is assumed that the mechanical shutter 102 linearly changes the aperture value at a constant speed without inertia and is closed within 3 fields from the current aperture amount. Further, as shown in FIG.
The vertical transfer pulse 1 and the ternary pulse of 3 are stopped until the mechanical shutter 102 is closed after 4, and the photo diode 20
The reading of charges from 1 is stopped. According to the above conditions, the exposure amount when capturing a still image, that is, the area indicated by B is 1.5 times the exposure amount when capturing a moving image, that is, the area indicated by A, as in the first embodiment. The exposure amount that is 1.5 times the exposure amount in the period from time t3 to t4 shown in FIG. T4 to t7 by the above method
The light incident on the image pickup element 103 during the period is photoelectrically converted and the ternary pulse of the vertical transfer pulses 1 and 3 is set to a high level once at each of the timings t7 and t8 after the mechanical shutter 102 is closed. It is output from the image sensor 103 by independent reading. However, since the independent reading is performed, the video signal processing circuit 106 switches the signal processing for a still image, converts the input signal into a video signal, and outputs the video signal. Further, at this time, the signal charge stored in the image sensor 103 is 1.5 times as large as that in moving image capturing, so that the total amount of signal amplification in the subsequent signal processing should be 1 / 1.5 times as much as in moving image capturing. good.

Further, since the video signal picked up during the period from t4 to t7 can be read out only once, when read out, it is recorded in a recording means such as a memory (not shown) and, if necessary, computer equipment or the like. Output as a still image to.

Next, a fourth embodiment of the present invention will be described with reference to the drawings.

The configuration of the image pickup apparatus according to the third embodiment of the present invention is common to that of the first and third embodiments described above, and will be described with reference to FIG. The description of the parts common to the first and third embodiments will be omitted. Also in the present embodiment, exposure control during still image capturing will be described assuming that the amount of charge accumulated in the image sensor 103 is 1.5 times that during moving image capturing.

FIG. 9 shows the mechanical shutter 1 in this embodiment.
FIG. 3 is a diagram showing the exposure amount to the image sensor 103 with respect to the aperture value of 02 and the transfer timing of charges from the photo diode 201 to the vertical CCD 202. The present embodiment is different from the third embodiment described above in that the illuminance of the subject is higher and the amount of exposure to the image sensor 103 is half that of the third embodiment. In the above-mentioned image pickup apparatus, the exposure control similar to that of a general video camera is performed as described in the first embodiment before starting the still image pickup operation. If the shutter button 110 is pressed at the time indicated by ts in FIG. 9 after the exposure control of the moving image is stabilized, the exposure for capturing the still image is started from the time t4. At this time, the mechanical shutter 102 linearly changes the aperture value at a constant speed without inertia, as in the third embodiment. That is, the time required to close the mechanical shutter 102 is halved to 1.5 fields. At this time, if the mechanical shutter 102 is closed from the next field when the shutter button 110 is pressed, that is, at time t4, as in the first embodiment, the exposure amount for still image capturing is set at time t.
It is not possible to increase the exposure amount by 1.5 times the exposure control performed during the moving image capturing from 3 to time t4. Therefore, even if the shutter button 110 is pressed, the camera control circuit 10
7 does not output a shutter close control signal to the mechanical shutter control circuit 109 for a fixed time determined by the method described below.

FIG. 10 shows a series of operations from when the shutter button 110 is pressed to when the camera control circuit 107 calculates the fixed time and outputs a shutter close control signal to the mechanical shutter control circuit 109. It is a flow chart. When the shutter button 110 is pressed, a shutter close control signal is input to the camera control circuit 107, the camera control circuit 107 determines the current aperture value of the mechanical shutter 102, and from the current aperture value of the mechanical shutter 102, The time required for closing the mechanical shutter 102 is calculated. Then, it is calculated how much the closing operation of the mechanical shutter 102 should be delayed in order to give the exposure amount 1.5 times the exposure amount by the exposure control performed at the time of capturing the moving image at the time of capturing the still image. The camera control circuit 107 causes the mechanical shutter control circuit 109 to release the shutter after the time obtained by the above calculation after the shutter button 110 is pressed.
Output a control signal to close the mechanical shutter 102. Although not shown, the camera control circuit 107 has means for recognizing the aperture value of the mechanical shutter 102, and determines the exposure amount to the image sensor 103 from the current exposure amount and the time required until the mechanical shutter 102 is closed. It has a means for calculating the above-mentioned fixed time required to give an exposure amount 1.5 times as much as that when capturing a moving image when capturing a still image. In this embodiment, by setting the fixed time to 1 field, the exposure amount at the time of still image capturing shown in FIG. The exposure amount at that time, that is, 1.5 times the area shown by A, becomes 1.5 times the exposure amount during the period from time t3 to t4, and the image pickup element 103 receives the exposure amount.
Can be given to. The light incident on the image sensor 103 from the time t4 to the time when the mechanical shutter 102 is closed by the above-described method is photoelectrically converted, and the vertical transfer pulses 1 and 3 of the vertical transfer pulse 1 and 3 are respectively once at the timings t7 and t8 after the mechanical shutter 102 is closed. The value pulse is set to a high level and is output from the image sensor 103 by the above independent reading. However,
Since the independent reading was performed, the video signal processing circuit 106
The signal processing is switched for still images, and the input signals are converted into video signals and output. At this time, the image sensor 103
Since the signal charge stored in the signal is 1.5 times that in the moving image capturing, the total amount of signal amplification in the subsequent signal processing may be 1 / 1.5 times that in the moving image capturing.

Further, since the video signal picked up from the time t4 to the time when the mechanical shutter 102 is closed can be read out only once, if read out, it is recorded in a recording means such as a memory (not shown), and if necessary, the computer. -Output as a still image to video equipment.

When capturing a still image, an exposure amount that is 1.5 times the exposure amount when capturing a moving image can be obtained. It is needless to say that the above-mentioned fixed time becomes longer accordingly when the subject is brighter and the exposure amount is smaller. In addition, as in the third embodiment described above,
As shown in FIG. 9, after the time t4, the ternary pulse of the vertical transfer pulses 1 and 3 is stopped until the mechanical shutter 102 is closed, and the reading of charges from the photo diode 201 is stopped.

Next, a fifth embodiment of the present invention will be described with reference to the drawings.

This embodiment has a part in common with the above-mentioned third embodiment, and a different part will be described. Also in the present embodiment, exposure control during still image capturing will be described assuming that the amount of charge accumulated in the image sensor 103 is 1.5 times that during moving image capturing.

FIG. 11 shows the exposure amount to the image sensor 103 with respect to the aperture value of the mechanical shutter 102 in this embodiment,
FIG. 3 is a diagram showing a transfer timing of charges from the photo diode 201 to the vertical CCD 202 and a timing of a charge sweep-out pulse supplied from the image sensor 108. The present embodiment is different from the third embodiment described above in that the illuminance of the subject is lower and the exposure amount to the image sensor 103 is twice that of the third embodiment described above. In the above-mentioned image pickup apparatus, the exposure control similar to that of a general video camera is performed as described in the first embodiment before starting the still image pickup operation. If the shutter button 110 is pressed at the time indicated by ts in FIG. 11 after the exposure control of the moving image is stabilized, the exposure for capturing the still image is started from the time t4. At this time, the mechanical shutter 102 linearly changes the aperture value at a constant speed without inertia, as in the third embodiment.
That is, the time required for the mechanical shutter 102 to close is doubled to 6 fields. At this time, if the mechanical shutter 102 is closed from the next field after the shutter button 110 is pressed, that is, from time t4,
The exposure amount for still image capturing is three times as large as the exposure amount by the exposure control performed during moving image capturing from time t3 to time t4. Therefore, while the shutter button 110 is pressed and the mechanical shutter 102 is performing the closing operation from time t4, the camera control circuit 107 uses the electronic shutter function of the image sensor 103 for a certain period of time determined by the method described below. The charges accumulated in the photo diode 201 are swept away.

FIG. 12 shows a series of operations after the shutter button 110 is pressed until the camera control circuit 107 calculates the fixed time and outputs a shutter close control signal to the mechanical shutter control circuit 109. It is a flow chart. When the shutter button 110 is pressed, a shutter close control signal is input to the camera control circuit 107, the camera control circuit 107 determines the current aperture value of the mechanical shutter 102, and from the current aperture value of the mechanical shutter 102, The time required for closing the mechanical shutter 102 is calculated. Then, in order to give an exposure amount of 1.5 times the exposure amount by the exposure control performed at the time of capturing a moving image at the time of capturing a still image, it is calculated how much the electric charges should be swept out by the electronic shutter function from time t4. . The camera control circuit 107 outputs a shutter close control signal to the mechanical shutter control circuit 109 to close the mechanical shutter 102 from time t4 after the shutter button 110 is pressed, and at the same time, the time obtained by the above calculation, The image sensor drive circuit 108 is controlled to supply the charge sweep pulse to the image sensor 103. Although not shown, the camera control circuit 107 has means for recognizing the aperture value of the mechanical shutter 102, and determines the current exposure amount and the mechanical shutter 10.
2 has a means for calculating the above-mentioned fixed time required to give the exposure amount to the image pickup element 103 1.5 times as much as that at the time of capturing a moving image, from the time required for closing the image capturing device 103. In this embodiment, by setting the above-mentioned fixed time to approximately 2 fields, it is possible to obtain an exposure amount that is 1.5 times the exposure amount when capturing a moving image when capturing a still image. Needless to say, if the subject is darker and the exposure amount is larger, the certain period of time becomes longer accordingly.

Further, since the video signal picked up from the time t4 to the time when the mechanical shutter 102 is closed can be read out only once, if read out, it is recorded in a recording means such as a memory (not shown), and if necessary, the computer. -It is output as a still image to video equipment. As in the third embodiment described above, as shown in FIG. 11, after the time t4, the mechanical shutter 1
The ternary pulses of the vertical transfer pulses 1 and 3 are stopped until 02 is closed, and the reading of charges from the photodiode 201 is stopped.

Next, a sixth embodiment of the present invention will be described with reference to the drawings.

FIG. 13 is a block diagram of an image pickup apparatus according to the embodiment of the present invention, in which the same parts as those in the first embodiment described above are designated by the same reference numerals and the description thereof is omitted. In the figure, 13
Reference numeral 01 is a mechanical shutter, and 1302 is an EEPROM (electrically rewritable ROM). In the third, fourth and fifth embodiments, the mechanical shutter 102 has an aperture value linearly at a constant speed without inertia. Although it is supposed to change, the mechanical shutter 1301 has inertia. That is, the shutter closing operation performed by the mechanical shutter 1301 after the shutter button 110 is pressed and the shutter close control signal is input to the mechanical shutter control circuit 109 follows the locus shown in FIG. The trajectory shown in FIG. 14 differs depending on the type of the mechanical shutter 1301.
Further, the mechanical shutters of the same type are not necessarily the same because of individual variations. Therefore, the locus of the used mechanical shutter 1301 during the closing operation is shown in the EEPROM 1302.
Record it in advance. In FIG. 14, the mechanical shutter 130 is shown.
Only three aperture values of 1 are shown, but the locus of the closing operation of the mechanical shutter 1301 at each arbitrary aperture value is recorded in the EEPROM 1302 as needed. The data recorded in the EEPROM 1302 may be recorded during automatic adjustment in the production process.

The locus of the closing operation of the mechanical shutter 1301 at each arbitrary aperture value may be recorded in other recording means.

The exposure control during still image pickup in this embodiment will be described below. Similar to the first, third, fourth, and fifth embodiments described above, before a still image capturing operation is performed, a moving image similar to that of a general video camera is captured, and exposure control performed by the general video camera is performed. Do. 15, 16, 17
Is the exposure amount to the image pickup device 103 with respect to the aperture value of each mechanical shutter 1301 when a still image is picked up in this embodiment, and the vertical CCD 202 from the photo diode 201.
FIG. 18 is a diagram showing a transfer timing of electric charges to and
9 is a flowchart showing an exposure control operation at the time of capturing a still image after the shutter button 110 is pressed.

As shown in FIG. 18, after the exposure control of the moving image is stabilized, the shutter button 11 is released at an arbitrary timing ts.
When 0 is pressed, the camera control device 107 displays the trajectory of the closing operation corresponding to the current aperture value of the mechanical shutter 1301 by E.
Read from EPROM. Then, based on the data from the EEPROM, in order to give an exposure amount 1.5 times the exposure amount by the exposure control performed at the time of capturing a moving image, at the time of capturing a still image, as shown in FIG. Whether to use the method of delaying the shutter closing operation performed in the fourth embodiment,
In addition, as shown in FIG. 16, the electric charge is swept out by the electronic shutter performed in the fifth embodiment described above,
As shown in FIG. 7, it is determined whether the shutter closing operation is to be performed from time t4 as in the third embodiment. If the result of the determination is that the shutter closing operation is delayed as in the case of the fourth embodiment, the camera control circuit 1
07 selects the a shown in FIG. 18, calculates how much the shutter closing operation is delayed from the time t4, and after the calculation time obtained from the time t4, that is, at the time tss shown in FIG. To the mechanical shutter control circuit. Further, if the judgment result is that the electric charges are swept out by the electronic shutter as in the case of the above-mentioned fifth embodiment, b shown in FIG. 18 is selected and the camera control circuit 10 is selected.
7 is time t4 which is the exposure start time for still image capturing.
From this, the time for sweeping out the electric charge by the electronic shutter is calculated, and at time t4, a shutter close control signal is output to the mechanical shutter control circuit 109, and at the same time, the image sensor drive circuit 108 is controlled for the time obtained by the above calculation. , Sweeping out the charges accumulated in the image sensor 103. Further, except for the above-mentioned two cases, that is, when it is not necessary to delay the shutter closing operation or to sweep out the electric charge by the electronic shutter, c shown in FIG. 18 is selected, and as in the third embodiment described above. At time t4
Output the control signal to the mechanical shutter control circuit 109,
The mechanical shutter 1301 is closed.

Although not shown, the camera control circuit 10
Reference numeral 7 denotes a means for recognizing the aperture value of the mechanical shutter 1301, and the exposure amount to the image sensor 103 from the current exposure amount and the data given from the EEPROM 1302 is set to 1.5 at the time of capturing a moving image at the time of capturing a still image. Means for determining whether any of the above methods should be used in order to double
It has means for calculating the time for delaying the shutter closing operation and means for calculating the time for discharging the electric charge by the electronic shutter. Further, since the video signal picked up from the time t4 to the time when the mechanical shutter 1301 is closed can be read out only once, when read out, it is recorded in a recording means such as a memory (not shown) and, if necessary, computer equipment. Etc. as a still image. As in the third, fourth, and fifth embodiments described above, as shown in FIGS. 15, 16, and 17, the ternary pulse of the vertical transfer pulses 1 and 3 is stopped until the mechanical shutter 102 is closed after time t4, and the photodiode- The reading of charges from the mode 201 is stopped.

[0043]

According to the present invention, it is possible to provide an image pickup apparatus capable of performing accurate exposure control at the time of picking up a still image and picking up a high quality still image.

[Brief description of drawings]

FIG. 1 is a block diagram showing a circuit configuration of an image pickup apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram showing a specific example of the image sensor according to the embodiment of the present invention.

FIG. 3 is a diagram showing the potential of the image sensor according to the embodiment of the present invention.

FIG. 4 is a diagram showing the potential of the image sensor according to the embodiment of the present invention.

FIG. 5 is a timing chart showing driving of the image sensor according to the embodiment of the present invention.

FIG. 6 is a timing chart showing driving of the image sensor according to the embodiment of the present invention.

FIG. 7 is a diagram showing an exposure amount to the image pickup device according to the embodiment of the present invention.

FIG. 8 is a diagram showing an exposure amount and driving of the image pickup device according to the embodiment of the present invention.

FIG. 9 is a diagram showing an exposure amount to an image pickup device and driving of the image pickup device according to an embodiment of the present invention.

FIG. 10 is a flowchart according to an embodiment of the present invention.

FIG. 11 is a diagram showing an exposure amount to the image pickup device and driving of the image pickup device according to the embodiment of the present invention.

FIG. 12 is a flowchart according to an embodiment of the present invention.

FIG. 13 is a block diagram showing a circuit configuration of an image pickup apparatus according to an embodiment of the present invention.

FIG. 14 is a diagram showing a locus of a closing operation of the mechanical shutter according to the embodiment of the present invention.

FIG. 15 is a diagram showing an exposure amount to an image pickup device and driving of the image pickup device according to an embodiment of the present invention.

FIG. 16 is a diagram showing an exposure amount to the image pickup device and driving of the image pickup device according to the embodiment of the present invention.

FIG. 17 is a diagram showing an exposure amount to an image pickup device and driving of the image pickup device according to an embodiment of the present invention.

FIG. 18 is a flowchart according to an embodiment of the present invention.

[Explanation of symbols]

 101 ... Lens 102 ... Mechanical shutter 103 ... Image sensor 104 ... Amplifier 105 ... A / D converter 106 ... Video signal processing circuit 107 ... Camera control circuit 108 ... Mechanical shutter control circuit 109 ... Image sensor drive circuit 110 ... Shutter button 201 ... Photodio- Reference numeral 202 ... Vertical CCD 203 ... Horizontal CCD 301 ... Charge 302 ... Readout gate 303 ... Substrate voltage 304 ... Well 305 ... Channel stopper 1301 ... Mechanical shutter 1302 ... EEPROM

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Naoki Yamamoto 1410 Inada, Katsuta-shi, Ibaraki Hitachi Ltd. AV equipment division (72) Inventor Tamiya Imade 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Hitachi, Ltd. Visual Media Research Center

Claims (11)

[Claims] 1. A solid-state imaging device having a light quantity limiting means for blocking a part of incident light, photoelectrically converting incident light for each pixel, and having a shutter function for sweeping away charges photoelectrically converted by the pixel at an arbitrary time. A signal processing unit that outputs a signal photoelectrically converted by the solid-state image sensor as a video signal; and a light amount limiting unit and the shutter function of the solid-state image sensor to control the exposure amount and to shoot a still image. At times, the image pickup apparatus has an exposure control unit that controls the exposure of the light amount limiting unit and the shutter function with an exposure amount that has been defined when shooting a moving image before that. 2. An incident light blocking control means for controlling the exposure control means so as to block the incident light by the light quantity limiting means, wherein the exposure control means receives the incident light from the incident light blocking control means. The image pickup apparatus according to claim 1, wherein the light amount limiting unit is controlled so as to completely block the incident light after the cutoff control is input. 3. The exposure control means after the incident light blocking control is input by the incident light blocking control means is more than the exposure amount before the incident light blocking control is input by the incident light blocking control means. The image pickup apparatus according to claim 1, wherein the light amount limiting unit and the shutter function are controlled so that the amount of light increases. 4. The image pickup apparatus according to claim 1, wherein the signals photoelectrically converted by each pixel of the solid-state image pickup element are independently output in pixel units. 5. The signal processing means generates a video signal by different signal processing when the solid-state image pickup device outputs a pixel signal independently and when the pixel mixture outputs the pixel signal. The image pickup apparatus according to claim 1, wherein 6. A solid-state imaging device having a light quantity limiting means for blocking a part of incident light, photoelectrically converting the incident light for each pixel, and having a shutter function for sweeping away the charges photoelectrically converted by the pixel at an arbitrary time. A signal processing unit for outputting a signal photoelectrically converted by the solid-state imaging device as a video signal; an exposure control unit for adjusting an exposure amount by controlling the shutter function of the light amount limiting unit and the solid-state imaging device; An incident light blocking control means for controlling the exposure control means so as to block the incident light to the light quantity limiting means, wherein the exposure control means receives the incident light blocking control from the incident light control means, and the light amount limiting means The solid-state imaging device outputs photoelectrically converted electric charges during the period from the field for blocking the incident light until at least the light amount limiting means completely blocks the incident light. An imaging device characterized by not doing. 7. The light quantity limiting means for preventing the light quantity limiting means from blocking the incident light for an arbitrary time after receiving the incident light cutoff control from the incident light cutoff controlling means. The image pickup apparatus according to claim 6, wherein the image pickup apparatus controls the means. 8. The solid-state imaging device, when the light quantity limiting means is operating to block the incident light after the exposure control means is subjected to the incident light blocking control from the incident light blocking control means, 7. The image pickup device according to claim 6, wherein the converted charges are swept away for an arbitrary time. 9. The exposure control means after the incident light blocking control is input by the incident light blocking control means is more than the exposure amount before the incident light blocking control is input by the incident light blocking control means. 7. The image pickup apparatus according to claim 6, wherein the light amount limiting unit and the shutter function are controlled so that the amount of light increases. 10. The image pickup apparatus according to claim 6, wherein the signals photoelectrically converted by each pixel of the solid-state image pickup element are independently output in pixel units. 11. The signal processing means generates a video signal by different signal processing when the solid-state image pickup device outputs the pixel signals independently and when the pixels are mixed and output. The image pickup apparatus according to claim 6, wherein: