JPH0544228B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a video signal recording device that converts a subject image into an electrical signal and records the electrical signal on a recording medium.

Conventionally, such video signal recording devices include:
Systems consisting of video cameras and VTRs that record moving images are well known. Such video signal recording devices generally have a standby mode in which the tape is loaded onto the drum and the head and capstan are kept rotating. In this standby mode, the actual recording operation is executed at the same time as the trigger switch is operated.

However, if the waiting time in this standby mode is long, there is a problem in terms of the life of the battery.

In addition, if the actual recording operation is started before the capstan motor etc. for recording has sufficiently started up in the imaging control area for imaging, the time from the start of operation to the start up of the image will not be accurate. Not recorded. The occurrence of such a situation becomes a particularly serious problem especially when recording still images. Further, operating the image sensor and the signal processing circuit in this state also poses a problem in terms of power saving.

In view of the above-mentioned points, it is an object of the present invention to provide a video signal recording device capable of achieving power saving and accurately recording video signals.

Embodiments of the present invention will be described in detail below with reference to the drawings.

Although the embodiments in this specification describe a still image video system using a magnetic disk as a medium, the present invention is not limited to this.

FIG. 1 is a block diagram showing one embodiment of the configuration of a still video camera.

1 in the figure is an imaging optical system. Reference numeral 2 is a constriction means, which may be physical or mechanical. 3 is a shutter means, which may be physical or mechanical. Further, it may also be used as the aperture 2. 5 is a photoelectric conversion element (imaging element) such as a CCD (Charge coupled device).

Reference numeral 4 denotes a color filter disposed in front of the imaging means 5, which may be of a stripe type, a mosaic type, or the like.

Further, this filter may be omitted in order to obtain only black and white images. 6 is the shutter time setting circuit;
Reference numeral 7 denotes a video signal processing circuit which converts the image information obtained from the conversion element 5 into an appropriate signal form. Reference numeral 8 denotes a driver circuit (imaging element driving circuit), which controls scanning, transfer, etc. of the conversion element 5. 9
is a shutter control circuit which controls the opening and closing of the shutter means 3 according to the setting value of the setting circuit 6. Reference numeral 10 denotes a sequence control circuit which controls the overall sequence of the still video camera of this embodiment. Reference numeral 11 denotes a motor control circuit, which is controlled by a sequence control circuit when the power switch is turned on. 12 is a motor synchronously controlled by the control circuit 11; 13 is a magnetic disk rotationally driven by the motor; 14 is a magnetic head (recording head); and 15 is a PG head. The rotation phase of the motor is transmitted to the motor control circuit 11. Give feedback. Terminal F is a terminal for outputting a servo lock signal, 16 is a clock oscillator, 17 is an electronic viewfinder device for displaying a subject image, 18 is a power switch, and 19 is a battery. 20 is a detector that detects the distance to the subject, 21 is a detector 20
This is an autofocus control circuit (hereinafter referred to as an AF control circuit) that controls a lens drive circuit 22 that drives the lens of the image sensor 1 according to the distance detected by the AF control circuit.

FIG. 2 shows a detailed circuit diagram of the sequence control circuit 10 of FIG. 1, and FIG. 3 shows a timing chart of each part of FIG. 2.

In FIG. 2, 25, 26, and 27 are timers with delay times τ ₁ , τ ₂ , and τ ₃ , respectively, 28, 29, and 32 are switches, 30 is a release button, and 31 is an indicator that indicates whether the release is possible. . The following will explain based on the timing chart shown in FIG.

When the power switch 18 is pressed, the battery 1
Power from 9 is applied to timers 25, 26, 27, oscillator 16, motor control circuit 11, electronic viewfinder 17, and display 31.

The motor control circuit 11 rotates the motor at the same time as power is applied, and starts control to rotate the magnetic disk at a predetermined speed using a synchronizing signal from the oscillator 16 and an output pulse from the PG head 15.

The power applied to the electronic viewfinder 17 begins to heat the cathode of the viewfinder 17. After a time τ ₁ from turning on the power switch 18, the output of the timer 25 (first timing signal) becomes high level.
Switch 28 is turned on. Then AF control circuit 2
1 and the lens drive circuit 22, and the focus is automatically adjusted.

Furthermore, after a time τ ₂ after the power switch 18 is turned on, the output of the timer 26 (second timing signal) becomes high level, the switch 29 is turned on, and power is supplied to the video signal processing circuit 7 and the driver circuit 8.

Then, after a time τ ₃ from turning on the power switch 18, the output of the timer 27 becomes high level, and the display 31
lights up to notify the photographer that it is possible to release the camera (shooting is possible).

When the photographer presses the release button 30 at this point, the switch 32 closes and the shutter control circuit 9 operates. Then, the shutter opens and closes, and the conversion element 5
A signal is applied to the recording head 14 via the video signal processing circuit 7, and recorded on the normally rotating magnetic disk 13. Here, power switch 1
Even if the release button 30 is pressed before the time τ ₃ has elapsed since the switch 8 was turned on, the output of the timer 27 is at a low level, so the switch 32 will not close. Therefore, no imaging and recording operations are performed.

Here, the rise characteristics of the motor control circuit 11 and the electronic viewfinder 17 are shown in FIG. 3 S4.
The rise characteristics of the control circuit 21 and the lens drive circuit 22 are shown in FIG. 3 S5, and the rise characteristics of the video signal processing circuit 7 and the driver circuit are shown in FIG. 3 S6. As shown in the figure, the time required from when power is supplied to the motor control circuit 11 until the magnetic disk actually rotates at a normal speed is time τ ₃ . The time from when power is supplied to the electronic viewfinder 17 to when the viewfinder becomes visible also substantially coincides with time τ ₃ .

Moreover, the AF control circuit 21 and the lens drive circuit 22
The maximum time required for the lens to reach the autofocus position after power is applied to the lens is time (τ ₃ −
τ ₁ ).

And a video signal processing circuit 7 and a driver circuit 8
The time required for the signal to be read from the conversion element 5 after power is supplied to the conversion element 5 is the time (τ ₃ −
τ ₂ ). And as is clear from the figure, τ ₁ < τ ₂
<τ ₃ , (τ ₃ - τ ₂ ) < (τ ₃ - τ ₁ ) < τ ₃ .

As described above, in this embodiment, during the time τ ₃ from turning on the power switch to when imaging becomes possible, the power is turned on in descending order of the time required for startup.

With this configuration, power consumption can be kept extremely low. In particular, power consumption can be minimized by finally matching the rise times of all the means necessary for photographing. In particular, AF
Power is turned on to the control circuit, lens drive circuit, etc.
Power is turned on to the signal processing circuit and CCD driver circuit after normal recording operation has been achieved, resulting in a significant reduction in power consumption.

In addition, since photographing is permitted only after the means necessary for photographing and recording are operating normally, recording errors or inappropriate recordings are prevented from occurring.

Although the sequence control circuit 10 shown in FIG. 1 determines the power-on timing for each part by the operation of a timer, other methods will be explained in the examples shown in FIGS. 4A and 4B and FIG. 5. In the figure, components having the same functions as those in FIG. 2 are indicated with a ``''' symbol.
In the figure, 50 and 51 are voltage dividing resistors, 52 are comparators, 53 and 55 are switches, 54 is a timer, 56 is a phase comparator, and 57 is a speed controller. Further, the signal Sa is the on signal of the power switch 18', Sb is the phase error signal, and Sc is the comparator 52.
, Sd is the output signal of the timer 54, and Se is a signal indicating the rising state of the signal processing circuit 7' and the driver circuit 8'.

When the power switch 18' is turned on, a synchronizing signal from the oscillator 16' is applied to the motor control circuit 11'.
At the same time, power is supplied to the motor control circuit 11'. The motor control circuit 11' includes a phase comparator 56 and a speed controller 57, as shown in detail in FIG. 4B.
The FG pulse from the motor 12' is fed back to the speed controller 57, and the DG pulse is fed back to the phase comparator. The phase comparator 56 compares the phase error between the synchronizing signal from the oscillator 16' and the PG pulse, and outputs a phase error indicating the phase error to the speed controller 57. This phase error signal Sb is input to one input terminal of the comparator 52. Comparator 52
A level LE voltage is input to the other input terminal. When the level of the error signal Sb decreases to a certain extent and falls below the level LE, the output Sc of the comparator 52 becomes high level and the switch 5
3 is closed, and power is supplied to the video signal processing circuit 7' and the driver circuit 8'. At the same time, the timer 54 also starts counting. The time measured by the timer 54 is τ ₄ , which is set to be approximately the same as the time required for the video signal processing circuit 7' and the driver circuit 8' to rise. When the timer 54 finishes counting, its output becomes high level, and the display 31' indicates that it is possible to take an image. Then, shooting is performed by operating the release button 30'. Furthermore, at the time when the timer 54 finishes counting, the level of the phase error signal Sb is 0.

In the method of this configuration example, by actually detecting the amount of phase error of the motor, it is ensured that the magnetic disk is rotating normally when the release button is operated, and the imaging signal can be accurately recorded.

FIG. 6 shows the configuration of a sequence control circuit 10 which is a second embodiment of the present invention using this method. In FIG. 5, components having the same functions as those in FIG. 2 and FIG. 4A are marked with "''.

61 and 66 are switches, 62 and 63 are resistors,
64 is a comparator.

After turning on the power switch 18'', the comparator 52'' indicates that the phase error signal has fallen below a certain level.
The output (first timing signal) closes the switch 61 and puts the AF control circuit 21'' and lens drive circuit 22'' into operation. The comparator 64 then detects that the level of the lens drive control signal, which indicates the amount of deviation of the AF control circuit 21'' from the focal point position of the lens drive circuit 22'', has fallen below a predetermined level. When the output (second timing signal) of the comparator 64 becomes high level, the switch 66 is closed and the video signal processing circuit 7'' and the driver circuit 8'' are turned on. The subsequent operation is similar to that of the circuit shown in FIG.

FIG. 7 shows signal waveforms at various parts in FIG. 6. S.A.
is the input signal of power switch 18", SB is the phase error signal, SC is the output signal of comparator 52", SD
is the lens drive control signal, SE is the comparator 64
SF is the output signal of timer 54'', SG
7 is a diagram showing the startup state of the video signal processing circuit 7'' and the driver circuit 8''.

As shown in FIG. 7, at time _T3 when the level of the phase error signal SB becomes zero, the level of the lens drive control signal SD becomes zero, and at the same time, the video signal processing circuit 7'' and the driver circuit 8'' also rise. Reference voltages 52'' and 64 are set.

In this manner, release is possible only when the magnetic disk rotates normally, the focus position is accurately aligned, and the signal processing circuit is turned on. Therefore, there is no focus shift and accurate magnetic recording is possible.

In the above embodiment, the power switch and release button were provided separately, but the power switch is turned on with the first stroke, and the release button is turned on with the second stroke.
It may be configured to operate by stroke.

As described in detail above, the present invention enables the signal processing circuit, the image sensor Since the configuration is such that power is applied to the drive circuit to enable recording, current consumption can be reduced without impairing quick shooting performance. Furthermore,
The recording operation starts after the recorder and camera complete preparations for recording and shooting.
Inappropriate recording can be prevented.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing an example of the configuration of a still/video camera, Fig. 2 is a circuit diagram of an embodiment of the sequence control circuit of Fig. 1, Fig. 3 is a signal waveform diagram of each part of Fig. 2, FIG. 4A is a circuit diagram with a partially changed configuration of the sequence control circuit in FIG. 1, FIG. 4B is a diagram showing details of the motor control circuit in FIG. 4A,
5 is a signal waveform diagram of each part of FIG. 4A, FIG. 6 is a circuit diagram of another embodiment of the sequence control circuit of FIG. 1, and FIG. 7 is a signal waveform diagram of each part of FIG. 6. . In the figure, 1 is an imaging optical system, 2 is an aperture means,
3 is a shutter means, 5 is a photoelectric conversion element (imaging element), 7 is a video signal processing circuit, 9 is a shutter control circuit, 10 is a sequence control circuit, 11 is a motor control circuit, 12 is a motor, 13 is a magnetic disk,
14 is a recording head, 18 is a power switch, and 21 is a
AF control circuit, 22 is a lens drive circuit, 25, 2
6 and 27 are timers, and 30 is a release button.

Claims (1)

[Scope of Claims] 1. An imaging optical system having a lens, an imaging device that converts a subject image via the imaging optical system into an electrical signal, an imaging device drive circuit that drives the imaging device, and an imaging device drive circuit that drives the electrical signal. a signal processing circuit that converts the recording signal into a recording signal; an autofocus control circuit that detects a subject distance; a lens drive circuit that drives the lens according to the subject distance detected by the autofocus control circuit; and the recording signal. a recording means for recording on a recording medium; a power switch; after the power switch is operated, a first timing signal is generated, and the first timing signal powers the autofocus control circuit and the lens drive circuit; generating a second timing signal after generating the first timing signal; supplying power to the image sensor driving circuit and the signal processing circuit by the second timing signal; A video signal recording apparatus comprising: a sequence control circuit that enables the recording means to perform recording after a signal is generated.