JPS61126876A - Electronic still camera device - Google Patents

Abstract

PURPOSE:To prevent generation of error of exposure time caused by opening and shutting speed in shutter mechanism by performing photo electric load read from the photodetector for odd field of solid image pickup element, by performing photo electric load read from the photodetector element for even field. CONSTITUTION:Shutter mechanism 18 is inserted between the optical lenses and the shutter mechanism 18 is driven by shutter driver 20. A central signal is given to shutter driver 20 to put the shutter mechanism on the closed condition more than one field period after passing one field period. During that period the control signal is given to a synchronous pulse generator 8 for the purpose of performing a photoelectric load read from the photodetector for the odd field of solid photographing element 2 and photoelectric load read from the received light element for the even field. Thus, substantial exposure time control is practiced by the element shutter function, identification of exposure time between the received light for odd and even fields is designed, and an optional and highly precise change and adjustment of exposure time of solid image pickup element can be conducted without anxiety of error in exposure time caused by opening and shutting speed in shutter mechanism.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to an electronic still camera device in which an optical image obtained by an optical system is made incident on a solid-state W1ilI element through a shutter mechanism, and particularly relates to an improvement in opening/closing control means for the shutter mechanism. .

[Prior art]

FIG. 8 is a diagram showing the configuration of an FI image recording section of a conventional electronic still camera device. An optical image of a subject (not shown) captured by a lens 1 of the imaging optical system is formed on a photoelectric conversion surface of a solid-state image sensor 2 installed at the focal position of the lens 1. The solid-state image sensor 2 converts the above-mentioned optical image of the object into an electrical signal, and provides the output vout to the color separation circuit 3. The color separation circuit 3 converts the applied electrical signal into a luminance signal Y.
and color difference signals R-Y and B-Y, which are supplied to the FM modulator 4. The FM modulator 4 receives a luminance signal Y, a color difference signal R-Y,
B-Y is FM modulated in each frequency band and supplied to the recording amplifier 5. The recording amplifier 5 amplifies each FM modulated signal and supplies it to the magnetic head 6. magnetic head 6
F sends the supplied signal to the recording track of the magnetic disk 7.
M Record.

The synchronizing pulse generator 8 provides a vertical transfer lock φV and a horizontal transfer lock φH for the 11il quadrant 2.

In addition to applying a sensor gate pulse SG, a timing pulse is applied to the color separation circuit 31'3 and the FM modulator 4. Further, the synchronization pulse generator 8 supplies a synchronization pulse for matching the operation timing of the imaging system with the operation timing and phase of the recording system to the synchronization detector 9 as one input.

As the other input of the synchronization detector 9, a PG pulse from a rotational phase detection pulse generator 10 attached to the magnetic disk 7 is given. Thus, the synchronization detector 9 compares the PG pulse with the synchronization pulse from the synchronization pulse generator 8, and sends a signal to the motor drive circuit 11 so that the rotational speed and phase of the magnetic disk 7 always match the operation timing of the imaging system. give to The motor drive circuit 11 drives the disk drive motor 12 based on the signal given from the detector 9.
to drive and control. As a result, the magnetic disk 7 rotates at a constant speed of 3600 rpm in a steady state, and one field of image is recorded during one rotation.

The recording gate circuit 13 is triggered by a recording command, that is, a trigger pulse TG, which is generated when the recording command switch 14 moved by the release button of the electronic still camera is turned on, and is triggered by a synchronizing pulse from the synchronizing pulse generator 8. Write pulse W with a width equivalent to one field period
G is applied to the recording amplifier 5, and the recording amplifier 5 is activated for only that period.

FIG. 9 is a diagram showing the operation of the conventional device having the above configuration.

A field (-3An-1, 8An.

SAn+1-...), B field (-S Bn-
1.

The signal (-VAn-) for each field at the output Vout of the solid-state image sensor 2 corresponding to SBn, SBn+1-)
1, Van-1, VAn, Van.

) are color separated and FM modulated as described above and input to the recording amplifier 5, but are not sent out as the output of the recording amplifier 5 when the write pulse WG is not applied. Now, at time t10, the recording command switch 14 is turned on.
When the trigger pulse TG is applied to the recording gate circuit 13, the write pulse WG is sent out from the recording gate circuit 13 between time points t20 and t30, and is applied to the recording amplifier 5. As a result, the recording amplifier 5 at time t
It is activated for one field period from t30 to t30, and supplies VAn to the magnetic head 6, for example. Therefore, the magnetic disk 7 contains one field of image signal VA.
n is recorded.

In FIG. 8, numeral 15 is an encoder, which outputs the luminance signal Y and the color difference signals R-Y, B-Y, which are the outputs of the color separation circuit 3.
and is converted into, for example, an NTSC signal and sent to the viewfinder 16. The content of the image taken can be monitored through the viewfinder 16.

By the way, the conventional electronic still camera device described above does not have a shutter for adjusting the exposure time. Therefore, as mentioned above, when the solid-state image sensor 2 is driven in frame accumulation mode to perform frame recording for two fields A and B, only IIm and recording can be performed with an exposure time of 1/30 seconds, and other exposures can be performed. Time cannot be selected. Note that when the solid-state image sensor 2 is driven in the field accumulation mode, imaging and recording can only be performed with an exposure time of 1/60 second. Therefore, in the case of a fast-moving subject, there is a problem in that a clear still image cannot be obtained. As a means to solve this problem, it has been considered to include a mechanical shutter like a normal film camera in the optical system. However, when a mechanical shutter is used to control the exposure time, errors tend to intervene in the exposure time because the rising or falling speed, that is, the response speed during the opening and closing operations of the shutter is relatively slow.

[Objective] The object of the present invention is to provide a system that allows the exposure time (light accumulation time) of a solid-state image sensor to be variably adjusted arbitrarily and with high precision, with almost no fear of interference from exposure time errors caused by the opening/closing speed of the shutter mechanism. To provide an electronic still camera device equipped with a shutter mechanism of simple construction, capable of obtaining clear still images even of fast-moving subjects, and capable of accurately extracting video signals suitable for frame recording. There is a particular thing.

〔overview〕

In order to achieve the above object, the present invention is characterized by the following configuration. That is, the electronic still camera device of the present invention is provided with a shutter mechanism so as to be able to open and close the optical path in an optical system that obtains an optical image of a subject, and is capable of batch-transferring solid-state imaging of photo charges corresponding to the incident optical image through the shutter mechanism. It is made to accumulate in the light receiving element of the element. Then, at a predetermined first point in time after a recording command is given, the photocharges accumulated in the light receiving element of the solid-state image sensor before this first point in time are collectively transferred to a vertical shift register;
The vertical shift register is driven at high speed from the first time point when the batch transfer is performed to the third time point after one field period has elapsed, and the charges in the vertical shift register are discharged to the outside. By controlling the solid-state image sensor during the period from the second point in time, which is the still image exposure time determined based on the photometric information, from the third point in time when the discharge of the electric charge is completed, to the point in time M3, Each light-receiving element is caused to accumulate photoelectric charges at the same time. Then, the shutter mechanism is kept in a closed state by a shutter closing means for at least one field period from the third time point, and during the period when the shutter mechanism is in the closed state, the light receiving element for odd fields of the solid-state image sensor is The device is characterized in that it is configured to read out photocharges and then read out photocharges from the even field light receiving elements.

Therefore, according to the present invention, substantial exposure time control is performed by the element shutter function of the image sensor itself, and the exposure period of the odd field light receiving element and the even field light receiving element is made the same by a mechanical shutter mechanism. It will be done.

〔Example〕

FIG. 1 is a diagram showing the configuration of an Ill image recording section according to an embodiment of the present invention shown in correspondence with FIG. 8. Therefore, the eighth
Components that are the same as those in the figures are given the same reference numerals and detailed explanations will be omitted.

In FIG. 1, 1A and 1B are lenses of the optical system, and an aperture opening groove 17. A shutter mechanism 18 is inserted. The aperture mechanism 17 is driven by an iris driver 19, and the shutter mechanism 18 is driven by a shutter driver 20. The operation of each of these drivers 19 and 20 is controlled by control signals from an exposure control circuit 30, which will be described later.

The solid-state image sensor 2 is composed of, for example, a CCO, and includes a φ■ driver 21 .
Vertical transfer lock φV and horizontal transfer lock φ respectively output from φH driver 22.8G driver 23
H, and is driven by a sensor gate pulse SG.

The output of the image sensor 2 is output from the amplifier 24. Sampling hold circuit 25. Amplifier 26. The light is supplied to the color separation circuit 3 via the LPF 27 and also to the COD photometry circuit 28 . The output of the COD photometry circuit 28 is supplied to the exposure control circuit 30 together with the output from an external photometry circuit 29 consisting of a photodiode or the like.

At a predetermined first time point after the recording command switch 14 (TG) is turned on and a recording command is given, the exposure control circuit 30 controls the exposure control circuit 30 to control the amount of data accumulated in the light receiving element of the solid-state image sensor 2 before this first time point. The photocharges that have been transferred are collectively transferred to the vertical shift register of the solid-state image sensor 2, and the vertical shift register is driven at high speed from the first time point at which the batch transfer is performed to the third time point after one field period has elapsed. still image exposure determined based on a control signal for discharging the charge in the vertical shift register to the outside, and photometry information obtained by the external photometry circuit 29 from a third point in time when the discharge of the charge is completed. A control signal for setting the SG applied to the solid-state image sensor 2 to rHJ and causing each light receiving element to accumulate photocharges at the same time during the period from the second point in time to the third point in time, It is provided to the synchronization pulse generator 8. Furthermore, a control signal for keeping the shutter mechanism 18 in the closed state is given to the shutter driver 20 for at least one field period from the third time point. Further, during the period when the shutter mechanism 18 is in the closed state, control is performed to read out photocharges from the light receiving elements for odd fields of the solid-state image sensor 2, and then read out photocharges from the light receiving elements for even fields. A signal is given to the synchronization pulse generator 8.

2 and 3 show the shutter mechanism 18 shown in FIG.
FIG. 2 is a diagram showing a specific configuration. In FIGS. 2 and 3, numeral 31 is a shutter plate made of a transparent material, and has a light-transmitting window, that is, a slit 32 in a part thereof. Rod-shaped cores 33a and 33b made of a magnetic material are provided at both ends of the shutter plate 31, and these rod-shaped cores 33a and 33b are selectively inserted into the hollow portions of solenoids 34a and 34b corresponding to the shutter driver 20 described above. It is something that can be attracted to people. The shutter plate 31 is placed at the pupil position K of the optical system as shown in FIG. It matches with ○.

The shutter mechanism 18 configured as described above has the following features. As will be described later, in this apparatus, the time point at which exposure to the image sensor 2 starts is a predetermined time Bl! from the first time point t1 when the photo charges of the light receiving element have been collectively transferred to the vertical shift register. This is the second time point t2, which is the second time point t2 in which all the light-receiving elements start accumulating photoelectric charges at the same time. However, if the shutter is installed near the light-receiving surface of the solid-state m-image element 2, such as a focal-brain type shutter, the edge of the shutter slit 32 will move while being projected onto the solid-state image sensor 2 when the shutter is closed. It will become something that we will continue to do. Therefore, the exposure end time differs in the moving direction of the shutter slit 32, resulting in a difference in the exposure time of each light receiving element. In this regard, as shown in the second factor, FIG. 3, in the case where the shutter plate 31 is installed at the pupil position IK of the optical system, there is an advantage that the above-mentioned difference in exposure time does not occur.

Next, the solid-state image sensor 2 will be explained in detail. As the solid-state 11111 element 2 used in this device, it is preferable to use a bulk transfer type element in which the photocharges accumulated in each light receiving element are collectively transferred to the outside of the light receiving element at the same timing.

For example, an interline transfer type C
CD solid-state image sensors are known. Regarding this type of element, see Journal of the Society of Television Engineers Vol. 137. N0IO(19
83) P776-781 "Ita M using high resistance MCZI board"
O8 type sensor ccom image element".

FIG. 4 shows a specific example of the solid-state image sensor 2 adopted in this device based on the above-mentioned viewpoint, and is an interline transfer type CCD.
40 is shown. 41 in the figure is a color filter R.
, G, and B on its surface, each forming one pixel. A vertical shift register 42 made of COD is provided adjacent to the light receiving element 41. These vertical shift registers 42 receive photocharges accumulated in the light receiving elements 41 and sequentially transfer them to a horizontal shift register 43 made of COD. The horizontal shift register 43 transfers the photocharges to the output section 44 in units of one horizontal scanning line. The output section 44 has a built-in preamplifier, and amplifies the minute current and outputs it from the output terminal Vout. Note that each input terminal of the interline transfer type CCD 40 is connected to a COD drive circuit (first
From 21 to 23) in the figure, sensor gate pulse SG, which is a reset pulse, and vertical register transfer lock φV1゜φ
V2. Horizontal register transfer locks φH1, φH2, etc. are supplied.

The light accumulation time in each of the light receiving elements 41 is
It is determined based on the timing of transferring charges from 1 to the vertical shift register 42.

FIG. 5 is a diagram showing a part of the above-mentioned FIG. 4.

As is clear from FIG. 5, the sensor gate 45 is
This is a common electrode formed commonly for each light receiving element 41.

Further, the vertical shift registers 42 are arranged alternately, with those that work effectively in odd fields as shown by thin arrows, and those that work effectively in even fields as shown by thick arrows, and a transfer lock φV1 is set for each group. ．． φV
2 are commonly supplied.

Thus, the photocharge batch transfer is performed as follows. That is, when the potentials of each part in FIG.

■In odd field, sensor gate pulse SG is rLJ and φV1 is “H”,
■ When the sensor gate pulse SG is "Si" and φV2 is rHJ when it is an even field, the sensor gate pulse SG changes from the H level to the L level.
The point at which the level changes is the point at which the batch transfer of the accumulated photocharges starts, and the point at which the sensor gate pulse SG changes from the L level to the H level is the point at which new light accumulation starts.

FIG. 6 is a diagram showing the timing when the interline type CCD 40 is operated in the moving image mode. In FIG. 6, VD is a vertical drive pulse and HD is a horizontal drive pulse. The numbers written on the HD are 1 to 525.
” corresponds to the horizontal scanning line number. The sensor gate pulse SG changes rHj and rLJ once per field. The photocharge of the light receiving element 41 is transferred to the vertical shift register 42 at the timing of the change in rLJ.

In other words, at this timing, the information of all pixels of one field is transferred into the vertical shift register 42. φ
V1. φV2 is a two-phase vertical register transfer lock and is also related to charge transfer from the light receiving element 41 to the vertical shift register 42, as described above. That is, in the first (odd) field, SG is r
Since φV1 is rHJ when it becomes LJ, the charges of all pixels related to the image of the first field are transferred to the vertical shift register 42 at this point. This charge is output as a video signal for a period of 16 m5 from the first H of the COD output signal. On the other hand, in the second (even) field, 275
Since φV2 is rHJ when SG becomes rLJ in the H-th period, the charges of all pixels related to the image of the second field are transferred to the vertical shift register 42 at this point. The transferred signal charge is transferred to the first COD output signal after "V register empty feed" in FIG.
It is output from H as a video output.

FIG. 7 shows the overall operation of this embodiment, particularly the driving timing of the C0D 40, the opening/closing timing of the shutter mechanism 18, etc. Before time 10 in the figure, the C0D 40 is driven in the normal moving image mode as explained in FIG. 6. Further, during this period, the shutter mechanism 18 is in an open state. When the recording command switch 14 is turned ON at time point to and the trigger pulse TG is sent out, the exposure control circuit 3
0, the synchronization pulse generator 8 responds to this, and at the first time t1, which is the timing of the next SG, the SG becomes "synchronized".
As well as φV1. Both φV2 becomes rHJ,
The photocharges of the odd and even field light receiving elements 41 of the CCD 40 that have been accumulated before time t1 are simultaneously transferred to the vertical shift register 42 in a batch. Then, at time t
During one field period up to 3, the vertical shift register 42 is driven at a frequency sufficiently higher than the normal frequency. As a result, all the signal charges in the vertical shift register 42 are discharged to the outside or are discharged to the substrate side at the COD output amplifier stage. Therefore, the discharged charge due to the above-mentioned high-speed driving is not substantially output. On the other hand, at time t2, SG becomes rHJ and the light receiving element 4 for odd and even fields
1 light accumulation is started at the same time. At time t3, the shutter 1111118 is closed, and subsequent light accumulation is stopped. After that, SG is "Shi", φV1 is "H", φV
2 becomes rLJ, the photocharges of the odd field are transferred to the vertical shift register 42, and then φVl, φ■
Since 2 is given at the normal frequency, the odd field signal is output in one field period up to time 4. This output signal is recorded on the first track of the magnetic disk 7.

At time t4, the shutter mechanism 18 becomes open.

And SG is "L", φV1 is "L", φV2 is rHJ
Therefore, the even field photocharges are transferred to the vertical shift register 42, and φV1 and φV2 are subsequently applied at the normal frequency, so that the even field signal is output in one field period up to time t5. This output signal is recorded on the second track of the magnetic disk 7.

Incidentally, the timing t3 at which the shutter structure 18 enters the closed state is always synchronized with SG and set at a time before SG becomes rLJ. In other words, at this time t3, S
It is set so that it always has a temporally constant positional relationship with respect to G.

In this way, in this device, the light accumulation in the light receiving element 41 starts from the rising time t2 of the pulse SG, and the shutter mechanism 18 closes just before the third time t3 when the next pulse SG arrives. I'm trying to finish it. Generally, mechanical shutters have lower exposure time accuracy than electronic shutters. However, the shutter mechanism 18 of this device
is always closed at a fixed time, that is, time t3, and the exposure time adjustment operation is performed exclusively by the adjustment operation at the rising time t2 of the pulse SG. Therefore, there is almost no possibility that errors caused by the response speed of the mechanical shutter will interfere with the exposure time. Furthermore, since the shutter mechanism 18 is in an open state during the odd field photocharge readout period, the even field photocharges are held in a state in which no unnecessary light is accumulated in the light receiving element 41 during the above period. . Note that the period in which the shutter mechanism 18 is closed may continue until after time t4 as shown by the broken line in FIG. There is.

According to the embodiments described above, the following effects are achieved. Generally, when controlling exposure using a mechanical shutter, exposure is performed with the shutter closed, then opened, and after a predetermined period of time, the shutter is driven so as to close the shutter again. Therefore, it is necessary to control the exposure time by performing two operations, ie, close→open and open→close, at high speed. Therefore, the structure of the shutter mechanism is difficult and difficult to manufacture. However, in the apparatus of the present invention, the shutter 18 is kept open during normal times, and the substantial exposure time control of the image pickup device is electronically performed using the pulse SG. The shutter mechanism 18 is in a closed state at least during the odd field photocharge reading period to block the even field photocharges from external light and maintain the initially accumulated state. Therefore, it is possible to make the exposure periods of both fields the same. In other words, the shutter mechanism 1 in this device
8 is not a direct element that determines the length of the exposure time, but only contributes to making the exposure period the same, and merely opens and closes in synchronization with the pulse SG over a period longer than one field period. That's fine. Therefore, it is sufficient for the shutter mechanism 18 to have a function of being in a closed state for one field period or more, and its structure may be simple, which has the advantage of being easy to manufacture. Note that since the shutter mechanism 18 is normally in an open state, so-called TTL photometry through the lens system is possible until just before the recording command switch 14 is turned on and the trigger pulse TG is generated. In this way, according to the present device, solid fil
By providing the element with an element shutter function and by simply opening and closing the shutter mechanism, it is possible to accurately extract a video signal suitable for frame recording.

Note that the present invention is not limited to the embodiments described above. For example, in the embodiment described above, the lenses 34a and 34b are used as shutter drivers for driving the shutter mechanism 18.
In the above example, the shutter plate 31 is opened and closed by selectively energizing them, but a combination of a motor and a spring is used to close the shutter plate 31 with the force of the spring, and the motor The shutter plate 31 may be opened by the rotational force of the shutter plate 31. Further, in the above embodiment, a sliding type shutter mechanism 18 is shown, but a rotating disk shutter with a slit opening or the like may be used. It goes without saying that various other modifications can be made without departing from the gist of the present invention.

〔Effect of the invention〕

According to the present invention, substantial exposure time control is performed by the element shutter function of the image sensor itself, and the exposure period of the odd field light receiving element and the even field light receiving element is made the same by a mechanical shutter mechanism. It will be measured. As a result, there is almost no risk of exposure time errors caused by the opening/closing speed of the shutter mechanism, and the exposure time (light accumulation time) of the solid-state AM element can be variably adjusted arbitrarily and with high precision. Therefore, it is possible to provide an electronic still camera device that is capable of obtaining clear still images even when the camera is in use, and has a shutter mechanism with a simple configuration that can accurately extract a video signal suitable for frame recording.

[Brief explanation of the drawing]

1 to 7 are diagrams showing one embodiment of the present invention, in which FIG. 1 is a block diagram showing the configuration of an image capturing and recording section of an electronic still camera device, and FIGS. 2 and 3 are diagrams showing the configuration of a shutter mechanism. FIG. 4 is a front view and side view showing the configuration of an interline type COD as a specific example of a solid-state image sensor, and FIG.
The figure is a diagram showing a part of Figure 4, Figure 6 is a diagram showing the operation timing in the moving image mode of the solid-state W&image element shown in Figures 4 and 5, and Figure 7 is a diagram showing the operation of the entire device. FIG. 3 is a diagram showing timing. FIGS. 8 and 9 are block diagrams showing the configuration of an image capturing and recording section of a conventional electronic still camera device and diagrams showing operation timing. IA, 1B... Lens, 2... Solid-state image sensor, 6.
... Magnetic head, 7... Magnetic disk, 10... Pulse generator for rotational phase detection, 12... Disk drive motor, 14... Record command switch, 17...
Aperture mechanism, 18... Shutter mechanism, 19... Iris driver, 20... Shutter driver, 21.
...φ■ driver, 22...φH driver, 23
...SG driver, 24.26...amplifier, 25
...Sampling hold circuit, 27...LPF,
30... Exposure control circuit. Applicant's agent Patent attorney Jun Tsuboi Figure 2 Figure 3 Figure 5

Claims (1)

[Claims] An optical system that obtains an optical image of a subject, a shutter mechanism that can open and close the optical path in this optical system, and a bulk transfer solid state that stores photo charges corresponding to the optical image incident through this shutter mechanism on a light receiving element. The photoelectric charge accumulated in the image sensor and the light receiving element of the solid-state image sensor is measured at a predetermined first time point after a recording command is given, and the photoelectric charge accumulated in the light receiving element of the solid-state image sensor before this first time point. A transfer means for collectively transferring photocharges that have been transferred to a vertical shift register;
Charge discharging means for discharging the charges in the vertical shift register to the outside by driving the vertical shift register at high speed until a third point in time after the field period has elapsed, and a third point in time when discharging the charges by the charge discharging means is completed. By controlling the solid-state image sensor during the period from the second point in time, which is determined by the still image exposure time determined based on the photometric information, to the third point in time, photoelectric charge is accumulated in each light receiving element at the same time. shutter closing means for closing the shutter mechanism for at least one field period from the third point in time; and shutter closing means for closing the shutter mechanism for at least one field period from the third time point; 1. An electronic still camera device comprising means for reading out photocharges from a light-receiving element for odd-numbered fields and then reading out photocharges from a light-receiving element for even-numbered fields.