JPH0412676B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical field to which the invention pertains] The present invention relates to a photographing and recording method using an electronic camera. More specifically, the present invention provides an electronic camera that captures an image by combining a mechanical or electro-optical shutter and a solid-state image sensor, and records the obtained video signal on a magnetic disk. This invention relates to a photographing and recording method that eliminates unnecessary power consumption.

[Description of prior art]

Conventionally, in electronic cameras that record by aligning the recording start positions of each track on concentric circles of a magnetic disk, the magnetic disk must rotate at a constant speed in phase synchronization with a synchronization signal when recording. Moreover, even when the time from the start of disk rotation to constant speed rotation was shorter, it took around 0.5 seconds. For this reason, conventionally the shutter button was
The magnetic disk is activated in advance by turning on the first step switch by pressing it halfway, and after reaching a constant rotation speed, the second step switch is turned on by fully pressing the switch to start the shooting and recording operation. I was letting it happen. Therefore, with an electronic still camera configured like this, it is a hassle to wait for the shutter button to be released after the shutter button is pressed halfway, so the user may end up waiting for the shutter to start with the shutter button pressed halfway. During this time, the magnetic disk continued to rotate at a constant speed, which resulted in rapid battery consumption.

Furthermore, with electronic cameras that have a recording device configured to align the recording switching positions of each track by using a conventional phase and speed servo, the motor that can be built into the camera is small and there may be restrictions on the driving torque. On top of that, as mentioned above, the time from release operation to photographing and recording becomes longer and longer, resulting in a fatal drawback of wasting a well-earned shutter opportunity.

[Object of the present invention]

The present invention solves these drawbacks of the prior art, and only requires rotating the magnetic disk for a short period of time after the release operation. The object of the present invention is to provide a photographing and recording method for an electronic camera that can satisfy both of the two requirements of low power consumption and quick shooting performance.

[Summary of the invention]

The present invention starts the rotation of the magnetic disk at the same time as the release operation, rotates the disk at a constant speed using only the speed servo, and performs the operation of discharging unnecessary charges from the image sensor, reading out signal charges after exposure, and recording on the disk. Performed with different synchronization signal timing,
For this purpose, the present invention is characterized in that, after the discharge of unnecessary charges is completed, the synchronizing signal generator is reset in synchronization with the detection of the recording start position of the disk.

[Explanation of Examples]

FIG. 1 is a block diagram showing an example of an electronic camera implementing the method of the present invention. In this electronic camera, a light beam introduced into the camera through a lens 3 is reflected by a quick return mirror 4 and guided to a finder optical system including a pentaprism 5 and an eyepiece lens 6.

A photometric element 7 is installed in a part of the finder optical system, and a photometric calculation circuit 19 outputs a shutter control signal. 8 indicates a diaphragm provided within the lens barrel.

A focal plane shutter 9 is installed behind the quick return mirror 4, and the video signal obtained from the image sensor 1 is sent to a preamplifier 1.
It is amplified by 0, passes through a process amplifier 11 for setting γ characteristics, a pre-emphasis circuit 12, an FM modulation circuit 13, is FM-modulated, and is then amplified by a recording amplifier 14.
The information is recorded from the magnetic head 15 onto the magnetic disk 2 by. The recording amplifier 14 has a control terminal, and only when a recording control signal 16 is applied to this terminal, current flows to the magnetic head 15 and recording is performed. Therefore, at other times, no recording is performed even if a video signal exists.

The control circuit 17 generates timing signals necessary for each part of the camera, and controls the release switch 18.
, the shutter control signal from the photometry calculation circuit 19, and the synchronization signal generation circuit 20.
The necessary control signals for each part are generated using the synchronization signal of

These control signals include, for example, scan start and stop signals and synchronization signals to the image sensor drive circuit 21 that generates a group of pulses necessary for scanning the image sensor 1, and a front curtain and rear curtain dual electromagnetic release focal plane shutter 9. The mirror drive circuit 2 sends front curtain release and rear curtain release signals to the shutter drive circuit 22 for flipping up the quick return mirror 4 and lowering it to the normal position after a certain period of time.
Mirror up/down signals to 3, recording amplifier 1
4, a rotation start signal st for the disk speed servo circuit 24, and a reset timing signal 33 serving as a gate signal for a reset signal for the synchronization signal generation circuit 20.

The magnetic disk 2 is connected to the motor 2 via the hub 25.
6, and is driven and rotated by this motor 26. For example, the motor 26 has a
An FG generator 27 that generates 32 pulses is directly connected, and its output is given to a speed servo circuit 24 for speed control. Speed servo circuit 2
4 is further connected to a speed detection circuit 28, which detects that the rotational speed of the motor 26 is within a certain speed error range suitable for recording, and outputs a constant speed signal 32 that becomes high level at that time. .

The camera is further provided with a PG 29 for detecting a specific position in the circumferential direction of the hub 25,
The time point at which this output PG pulse 35 is generated is defined as the recording start position.

AND gate 30 is 1 generated from PG29
A PG pulse 35 for one rotation and a reset timing signal 33 are input, and the output thereof is applied to a delay circuit 31. This delay circuit 31 is
A delay time γ of several H (1H is one horizontal scanning period) is given to the reset signal 34 applied to the control circuit 17 and the synchronization signal generation circuit 20. When the synchronization signal generation circuit 20 is reset by the reset signal 34, the synchronization signal generation circuit 20 outputs a
For example, synchronization signal generation is started from the leading edge of the vertical synchronization signal.

The operation of the electronic camera having the configuration shown in FIG. 1 will be described below with reference to the timing chart shown in FIG.

FIG. 2a shows the ON signal of the release switch 18. That is, when the release button is pressed down and the switch 18 is turned on, the release on signal becomes high level as shown in a, and this is the control circuit 1.
7 and starts the camera's imaging and recording operations. The illuminance of the photometric element 7 at the moment when the ON signal becomes high level is stored in the photometric calculation circuit 19 and prepared for use in subsequent shutter time control.

As shown in a, from the time when the release-on signal becomes high level, the rotation start signal st is applied to the speed servo circuit 24 of the disk 2, and the mirror up signal is applied to the mirror drive circuit 23. Therefore, the rotational speed of disk 2 starts to rotate at a predetermined speed, for example, 3600 rpm constant speed, as shown in b, and as it goes, one shot per rotation.
As the PG pulse 35 is generated as shown in c,
The quick return mirror 4 begins to rise as shown in e. As the time required for the light beam to reach the shutter 9 side due to the rise of the quick return mirror 4, 3 fields/50 msec is sufficient.

Additionally, during this time, unnecessary charges are discharged from the image sensor 1 at the timing of the synchronization signal at the time when the release is turned on. After the mirror 4 has been raised sufficiently, the shutter 9 is opened and exposure is performed as shown in g for a period of time based on the photometric value stored in advance. During this exposure, the image sensor 1 is in the signal charge accumulation mode.

At the same time as the shutter 9 is opened, a reset timing signal 33 as shown at h is applied to one input of the AND gate 30 at a high level. Therefore, PG pulse 3 generated from now on
5 passes through the AND gate 30 and further passes through the delay circuit 3
1 to begin resetting the synchronization signal generation circuit 20. The reset pulse which is the output of the delay circuit 31 is shown at i. Reset synchronization signal generation circuit 2
0, a vertical synchronization signal V.Sync is generated at the reset instant f. Therefore, the vertical synchronization signal V.Sync after being reset is PG pulse 35.
This occurs with a delay of time r. This time r is
As mentioned above, several times one horizontal scanning time, e.g.
It is selected to be around 5H to 10H.

Disk 2 is subjected to only speed servo and no phase servo. Therefore, the time it takes to reach a constant speed is extremely short, about 100 msec, so even if the above-mentioned exposure operation is performed with the intention that the disk will reach a constant speed and is completed before then, the signal from the image sensor 1 will be The charge retention time is a short time that poses no practical problem, and recording on the disk becomes possible before signal deterioration due to dark current or the like occurs. d shows the constant speed rotation signal 32 of the disk 2. This signal is output from a speed detection circuit 28 provided attached to the speed servo rotation 24, and is set to be at a high level when the rotation speed reaches a speed that can be considered as constant speed rotation. This constant speed signal 32
After reaching a high level, recording can be performed correctly, so after reaching a high level,
Recording may be performed from the timing of the first PG pulse. This situation is shown by the recording control signal 16 of j. Note that if the horizontal synchronizing signal is not reset using the PG pulse, problems may occur due to the reset signal being input during recording as in the example, so in that case, the recording timing may be changed by one field from the recording timing shown in the example. You can try delaying it by a minute. In that case, the configuration may be such that recording starts with the first PG pulse after the final reset pulse.

In FIG. 2j, the recording control signal 16 is indicated by a solid line for one field recording. Furthermore, in the case of recording one frame, that is, two fields, it is sufficient to lengthen the length by one more field as shown by the broken line.

Immediately after recording is completed, the mirror 4 descends as shown in e, and again gives an optical image to the viewfinder side. In addition, in order to perform continuous shooting, the release-on signal must be at a high level after the first frame has been shot and a predetermined time has elapsed, that is, at the continuous shooting start point shown in a. This is possible by providing a detection means for detection and repeating a new image capturing/recording operation based on its output.

In terms of operation, a continuous shooting/single shooting selection switch (not shown) is provided in addition to the release button, so that when the continuous shooting side is selected and the release button is held down, continuous shooting is performed. It's convenient. In this continuous shooting mode, at the start point of continuous shooting after a predetermined period of time after the shooting of one frame is completed, it is determined whether or not the disk 2 should continue to rotate at a constant speed. If so, continue the rotation, and if it is low level, stop the rotation.

In the continuous shooting mode, since the disk 2 is already rotating at a constant speed, preparation for recording is completed with only one reset pulse.

In the above explanation, the timing for opening the shutter is after a certain period of time has elapsed after the release is turned on. However, the present invention is not limited to this, and the timing when the disc 2 stops rotating after the release is turned on is not limited to this. Exposure may begin once a rotational speed is reached that is constant relative to and lower than the final constant speed, or alternatively the exposure may be determined for the time in between and then continue until the final speed is reached. The exposure timing may be determined by predicting the time.

Furthermore, although Fig. 2 only shows cases where the shutter time is short, if the shutter time, that is, the exposure time is long, and the speed reaches a constant speed before the exposure is completed, the rotation may be disturbed by external disturbances, etc. In order to prevent this, it is preferable to configure the reset timing signal 33 to be maintained at a high level until the exposure is completed.This embodiment is shown in FIG. 3, and the operating waveform diagram is shown in FIG. 4.

In FIG. 3, the part surrounded by a dashed line is a part of the control circuit 17, and for the sake of simplicity, ancillary circuits such as power supply reset are omitted. This control circuit 17
The flip-flop 41 and the D flip-flop 43 are respectively set by the exposure start signal 36. In addition, the flip-flop circuit 41
is reset by the exposure stop signal 37, and the θ output of this flip-flop circuit 41 is applied to the D flip-flop 42. The inverted PG pulse 35 is applied to the clock terminal of the D flip-flop 42.
3 is supplied with a reset signal 34. Gate 44 receives A signal 38 from D flip-flop 42 and B signal 3 from D flip-flop 43.
9 is input, and a reset timing signal 33 is output.

As shown in FIG. 4a, each flip-flop 41, 43 is set by the rise of the exposure start signal 36, and as a result, the B signal 39 becomes high level as shown in f. If the exposure time is short and the flip-flop 41 is reset by the exposure stop signal 37 before the inverted PG pulse is applied, the A signal 38, which is the θ output of the flip-flop 42, remains at a low level. In the case of a long exposure time shown in FIG. 4, the A signal 38
follows the B signal 39 (see f) and becomes high level as shown in e. If the constant speed signal 32 becomes high level as shown in d before the exposure is completed,
This is detected and at the next reset signal timing,
The flip-flop 43 is reset, and its θ output, the B signal 39, becomes low level as shown at f. However, at this point, the A signal 38 still remains high until the exposure is complete and the first PG pulse passes through the gate 30.

Therefore, since the reset occurs after the completion of exposure until the time of recording, it is possible to ensure a strict positional relationship between the PG pulse and the vertical synchronization signal, and it is possible to minimize rotational disturbances caused by disturbances during the process. .

FIG. 5 is a configuration block diagram of the main parts showing another example of the configuration of the delay circuit when the synchronization signal generator 20 has a structure in which the horizontal synchronization signal generation circuit and the vertical synchronization signal generation circuit can be reset independently. .

In this figure, the synchronization signal generation circuit 20 includes:
It is provided with a horizontal reset terminal HR and a vertical reset terminal VR, and a portion 50 surrounded by a broken line functions as a delay circuit.

Here, the PG pulse 35 is the AND gate 3
The horizontal reset terminal passes through 0 without any delay.
Applied to HR. As a result, first, the horizontal synchronization signal H.Sync synchronizes with the PG pulse. At the same time, the output of AND gate 30 is output from flip-flop 5.
1, and its θ output becomes a high level and is input to the AND gate 52. A horizontal synchronizing signal H.Sync is applied to the other input of this AND gate 52, and the output of the gate 52 is counted by a counter 53. counter 5
3 is provided with an AND gate 54. In this example, when both the ABC outputs become high level, the output of the AND gate 54 becomes high level, and the counter 53 and flip-flop 51
Reset. For such a configuration, the following
Counter 53 stops until a PG pulse is generated through gate 30.

The reset signal output from the AND gate 54 is connected to the vertical reset terminal of the synchronization signal generation circuit 20.
VR is applied, and the vertical synchronization signal is from the PG pulse.
This occurs with a delay of about 7H, and the desired operation can be achieved with a simple delay circuit.

[Effects of the present invention]

As described above, according to the present invention, the magnetic disk starts rotating as soon as the shutter button is pressed, and since only the speed servo is used, the time to reach servo lock is short, and after reaching constant speed rotation, As long as exposure is completed, it is possible to record from the initial recording start position, so the power consumption due to spare disk rotation is extremely low, and the quick shooting performance is excellent, so there is no fear of missing a shutter start.
Moreover, signal charges accumulated in the image sensor due to exposure can be recorded quickly, and there is less deterioration due to dark current.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing an example of an electronic camera implementing the method of the present invention, Fig. 2 is a timing chart of its operation, Fig. 3 is a block diagram showing part of a control circuit, and Fig. 4 is a block diagram showing an example of an electronic camera implementing the method of the present invention. A timing chart of the operation is shown in FIG. 5, which is a block diagram showing an example of a delay circuit used in the camera of FIG. 3. 1...Image sensor, 2...Magnetic disk, 3...
Lens, 9...shutter, 15...magnetic head, 17...control circuit, 24...speed servo circuit.

Claims (1)

[Scope of Claims] 1. A photographing and recording method for an electronic camera which captures an image using a combination of a mechanical or electro-optical shutter and an image sensor and records the obtained video signal on a magnetic disk, the method comprising: The operation starts the rotation of the magnetic disk and the operation of its speed servo, and
Unnecessary charge is discharged from the image sensor at a first synchronization timing based on a synchronization signal generated from a synchronization signal generation circuit, and then exposure to the image sensor is started by opening the shutter before the magnetic disk rotates at a constant speed. After the exposure is completed, the synchronization signal generation circuit is reset by a reset pulse generated in synchronization with the PG pulse indicating the recording start point of the magnetic disk, and new synchronization with the reset pulse is performed from the first synchronization timing. The electronic camera is characterized in that the electronic camera shifts to a second synchronization timing, and reads out signal charges accumulated in an image sensor due to exposure and records video signals on a magnetic disk at the second synchronization timing. Shooting and recording method. 2. A photographing and recording method for an electronic camera that captures an image using a combination of a mechanical or electro-optical shutter and an image sensor, and records the obtained video signal on a magnetic disk, the method comprising: Therefore, the rotation of the magnetic disk and the operation of its speed servo are started, and unnecessary charges are discharged from the image sensor at the charge discharge synchronization timing based on the synchronization signal generated from the synchronization signal generation circuit, and then the shutter is activated. The exposure of the first frame on the image sensor is started before the magnetic disk rotates at a constant speed, and after the exposure is completed, a reset pulse is generated in synchronization with a PG pulse indicating the recording start point of the magnetic disk. The synchronization signal generation circuit is reset and the synchronization timing for discharging the charges is shifted to the synchronization timing for reading and recording which is synchronized with the reset pulse, and the signal charges accumulated in the image sensor due to exposure are read out and the video signals are thereby read out. Recording to the magnetic disk is performed at the synchronized timing for reading and recording, and for the second and subsequent frames in continuous shooting mode, the constant rotation of the magnetic disk is maintained while the shutter button is held down, and the shutter button is not pressed. After the release, the rotation of the magnetic disk is stopped when the last recording is completed, and the synchronization timing for reading and recording used for recording in the preceding frame is adjusted for imaging in the subsequent frame for two consecutive frames. In addition to being used as is to discharge unnecessary charges from the element, the synchronizing signal generating circuit is reset by a new reset pulse generated in synchronization with the PG pulse indicating the recording start point of the magnetic disk after the completion of exposure of each frame. At that point, a transition is made to a new read/record synchronization timing that is synchronized with the new reset pulse, and the readout of the signal charge accumulated in the image sensor due to exposure and the recording of the video signal onto the magnetic disk are changed to the new readout/recording synchronization timing. A photographing and recording method for an electronic camera is characterized in that the photographing and recording method is carried out at synchronized timing for reading and recording.