JPS6249785A - Electronic still camera - Google Patents

Abstract

PURPOSE:To decrease power consumption by supply driving power to an image pickup means and a signal processing circuit by the operation of the first and second switches, executing the image pickup and recording of an object after said components are stabilized, then stopping said supply of drive power immediately after ending the pickup and recording to limit the supplying period of driving power supply to said means and circuit, to the necessary minimum. CONSTITUTION:When the first operational switch 13 is depressed at a time T1, a first power supply source switch 11 closes, and the drive power is supplied to a synchronizing signal generating circuit 7, a recording medium driving means 6 from the power supply source. After the recording medium 5 goes to normal state, the second operational switch 14 is depressed and a second power supply source switch 12 closes. Then, the drive power is supplied to the image pickup device 3 and a signal processing circuit 4; both 3 and 4 rises in a short time to attain a normal state at a time T4. The image picking-up of the object is stated under the instruction from a system controlling circuit 9 in synchronization with the first synchronizing signal after the time T4. When the recording in the recording medium 5 ends, the supply of the drive power to the device 3 and the circuit 4 is immediately stopped.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an electronic still camera that takes and records still images, and particularly to power saving of an electronic still camera.

Conventional technology Conventional examples of power saving for electronic still cameras include:
There are two main types: JP-A-58-33370 and JP-A-58-96475. The former is the first. A second switch is provided, and when the first switch is operated, power is supplied to all the circuits of the electronic still camera, and the disk motor, which has the largest electrical inertia among the parts that make up the electronic still camera, drives the recording medium. The camera is configured to photograph and record a subject by operating a second switch (corresponding to a shutter switch) after the rotation of the drive means (driving means) has stabilized to a steady state. The latter instantly supplies power to all circuits and photographs the subject by operating the shutter switch.
This object image is held in the imaging device, and after the disk motor reaches steady rotation, the object image is read out from the imaging device and recorded.

Problems to be Solved by the Invention However, the conventional example of the above configuration has the following problems.

First of all, the problem with the former is that power is supplied to all circuits by operating the first switch, so the period of power supply is longer than the period required for actual shooting and recording, and the power saving effect is small. There is.

In the latter case, after photographing the subject, it is necessary to hold the subject image in the image sensor until the motor rotates steadily and it can be recorded.This period is relatively long, so There is a problem in that the SN ratio of the recorded image deteriorates due to dark current generated in the image sensor. By the way, the time it takes for a disk motor to reach steady rotation is generally about 0.3 seconds or more, and in current image sensors, the dark current generated during this time is extremely large, and the image quality is The deterioration of the SN ratio cannot be ignored.

Means for Solving the Problems In order to solve the above problems, the present invention provides an imaging means for converting optical information into an electrical signal, a signal processing circuit for processing an output signal of the imaging means, and the signal processing circuit. a recording medium for recording an output signal of the recording medium, a driving means for driving the recording medium, and a synchronization signal generation circuit for generating a synchronization signal for synchronizing the signal processing circuit and the driving means for the imaging means;
A control circuit is provided, and the control circuit supplies driving power to the driving means and the synchronization signal generation circuit by operating a first switch, and then by operating a second switch after the recording medium is stabilized. The driving power is supplied to the imaging means and the signal processing circuit, and after the imaging means and the signal processing circuit are stabilized, the subject image is photographed and recorded, and immediately after the photographing and recording is completed, the imaging means and the signal processing circuit are activated. This is designed to stop the supply of drive power to the signal processing circuit.

Effects of the Invention With the above-described configuration, the present invention can reduce the supply period of driving power to each circuit/means of the electronic still camera to the necessary minimum, thereby making it possible to reduce the power consumption of the electronic still camera.

Embodiment FIG. 1 is a block diagram showing a first embodiment of the present invention. In FIG. 1, 1 is a lens, 2 is a shutter, 3 is an imaging device, 4 is a signal processing circuit, 5 is a recording medium, 6 is a driving device for the recording medium, 7 is a synchronization signal generation circuit, and 8 is the state of the recording medium. Detector, 9 is a system control circuit, 1o is a power supply, 1
1 is a first power switch, 12 is a second power switch,
13 is a first operation switch, and 14 is a second operation switch. Next, the operation will be explained using the timing chart shown in FIG. When the first operating switch 13 is pressed at time T1, the system control circuit 9 issues a command to close the first power switch 11, as shown in FIG. 7. Drive power is supplied to the recording medium drive device 6 from the power supply 10. After the supply of driving power is started, the synchronizing signal generating circuit starts up in a short time and reaches a steady state, and a synchronizing signal for keeping the entire system synchronized is generated as shown in FIG. 2(i). On the other hand, if the recording medium 5 and its driving device 6 are composed of, for example, a magnetic sheet and a disk motor that rotates it, the recording medium 5 has a large inertia and requires a considerable amount of time to reach a steady state after power supply is started. (The current technology requires 0.2 to 0.3 seconds or more.) This state is 0 as shown in FIG. 2(d).The state of the storage medium 5 is detected by the state detector 8, and at time T2 When the steady state is reached, the signal is sent to the system control circuit 9.

Note that this steady state is a state in which signals can be normally recorded on the recording medium 5, and in the case of a magnetic sheet,
0 refers to a state in which the recording medium 5 rotates at a steady rotation speed and the rotational phase is also at a predetermined phase. Then, after the recording medium 5 reaches a steady state, when the second operation switch 14 is pressed at time T3, the 7 stems are rotated. The control circuit 9 detects this and issues a command to close the second power switch 12. Figure 2 (C
), when the second power switch 12 is closed, driving power is supplied to the imaging device 3 and the signal processing circuit 4.
The imaging device 3 and signal processing circuit 4 start up in a short time,
A steady state is reached at time T4. Then, in synchronization with the first synchronization signal after this, the shutter lid 2 is opened at time T6 by a command from the system control circuit, and the image of the subject (not shown) is guided through the lens 1 to the imaging device 3. The subject is photographed and the state is maintained until time T6 after a predetermined exposure period (this state is shown in FIG. 2(q)).

Note that the subject image is accumulated and held in the imaging device from time T5 until time T7 when the first synchronization signal is generated after the shutter 2 is closed again at time T6. Then, during the period from time T7 to T8, FIG. 2(h)
As shown in FIG. 3, a recording gate is generated, and the accumulated and held subject image is read out from the imaging device 3 and recorded on the recording medium 5 via the signal processing circuit 4. Immediately after recording is completed at time T8, the second power switch 12 receives an opening command, and the supply of drive power to the imaging device 3 and signal processing circuit 4 is stopped, and one photographing operation is completed.

On the other hand, the first power switch remains closed, and the timing state for the next photographing command is maintained. However, this state occurs only at time T, which is a predetermined time after the previous shooting command.
9, and the supply of driving power to the synchronizing signal generating circuit a and the recording medium driving device 6 is also stopped.

With the above configuration, the period for supplying driving power to each circuit and device inside the electronic still camera can be kept to the minimum necessary and power can be saved. Even in this case, the period from when a photographing command is issued (pressing the second operation switch 14 of the tab 9) until the actual photographing starts (in FIG. 2, the period from time T3 to T5) ) is determined by the rising period (period from T3 to T4) of the image pickup device 3 and the signal processing circuit 4, but this rising period is the rising period of a general electric circuit, and is approximately 20 to 30 minutes.
Since it can be designed to take about m seconds, there is no problem in practical use. Furthermore, since the period for accumulating and retaining the subject image within the imaging device is short, there is no peak.

In the above description of the embodiment, the first . Although the configuration is such that the second two operation switches are provided, this may be configured with only one operation switch. At this time, the first operation of this one operation switch (that is, the synchronization signal generation circuit 7 and the recording medium drive device 6
, the operation when the drive power is not supplied) has the same effect as the suppression of the first operation switch 13 in the first embodiment, and this operation after the recording medium 5 reaches a steady state. This is achieved by making the operation of each operation switch have the same effect as the suppression of the second operation switch in the first embodiment.

This configuration diagram is shown in FIG. 3, and the timing diagram is shown in FIG. 4.

The configuration and operation are the same as those in FIGS. 1 and 2, except that the number of operation switches 13 is one, so the explanation will be omitted.

As described in detail, according to the present invention, the period of supply of driving power to each circuit and device inside the electronic still camera can be minimized to the necessary minimum without interfering with the operation and operation of the electronic still camera. Therefore, power saving can be achieved. In particular, the supply period of driving power to the image pickup device, which has the greatest power savings in the electronic still camera, is extremely short, resulting in a large power saving effect.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a first embodiment of the present invention;
3 is a block diagram showing another embodiment of the present invention, and FIG. 4 is a timing diagram thereof. 1...Lens, 2...Shutter, 3
...imaging device, 4...signal processing circuit,
5... Recording medium, 6... Recording medium drive device, 7... Synchronization signal generation circuit, 8...
・Recording medium status detection circuit, 9... System control circuit, 10... Power supply, 11.12...
・1st゜second power switch. Name of agent: Patent attorney Toshio Nakao and 1 other person 2nd
Figure r 17

Claims (2)

[Claims] (1) An imaging means that converts optical information into an electrical signal, a signal processing circuit that processes the output signal of the imaging means, a recording medium that records the output signal of the signal processing circuit, and driving the recording medium. A drive means, a synchronization signal generation circuit that generates a synchronization signal for synchronizing the imaging means, the signal processing circuit, and the drive means, and a control circuit, and the control circuit is configured to generate a synchronization signal by operating a first switch. Drive power is supplied to the drive means and the synchronization signal generation circuit, and then, by operation of a second switch after the recording medium is stabilized, drive power is supplied to the image pickup means and the signal processing circuit; An electronic device characterized in that the image of the subject is photographed and recorded after the signal processing circuit is stabilized, and the supply of driving power to the imaging means and the signal processing circuit is stopped immediately after the photographing and recording is completed. still camera. (2) The first switch and the second switch are configured with a single switch, and the control circuit supplies drive power to the drive means and the synchronization signal generation circuit by the first operation of the single switch. Then, after the recording medium has stabilized, driving power is supplied to the imaging means and the signal processing circuit by operating the single switch, and after the imaging means and the signal processing circuit have stabilized, the subject image is photographed and recorded. Immediately after photographing and recording are completed, the supply of driving power to the imaging means and the signal processing circuit is stopped, and the supply of driving power to the driving means and the synchronizing signal generating circuit is continued for a certain period of time. Claim 1 characterized in that
Electronic still camera as described in section.