JPS60170380A - Electronic still camera - Google Patents

Abstract

PURPOSE:To prevent the drop of power source voltage and the generation of noise by detecting the time of starting image pickup to an image pickup element and the time of completion of picture wiring to a recording medium and sending out the first and second signals and thereby stopping the charging of a stroboscope from the start of acumulation of picture signals until the completion of recording. CONSTITUTION:Picture information obtained by an image sensor 12 of an electronic still camera is added to a magnetic head 24 through a signal recording circuit 16 and accumulated in a recording medium by the head 24. The time of starting image pickup of the sensor 12 is controlled by an exposure controlling circuit 10 connected to a light receptance sensor 6 and a shutter 8, and the time of starting image pickup is inputted to an FF. The time of completion of picture writing to the recording medium is detected by a PG detecting coil 26, and inputted to the FF44 through a driving timing controlling circuit 20 and a differentiating circuit 42. A light emission tube 58 is controlled by output of the FF44, and charging of a strobe is stopped during the period from accumulation of video signals to the completion of recording to prevent the drop of power source voltage and the generation of noise.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to an electronic still camera that records signals obtained from an imaging device such as a solid-state imaging device or an image pickup tube onto a recording medium such as a magnetic disk. be.

Prior Art and Problems In recent years, it has become possible to take still images of subjects purely electronically by combining imaging devices such as solid-state imaging devices and image pickup tubes with recording devices that use inexpensive and relatively large-capacity magnetic disks as recording media. However, an electronic still camera has been devised in which the images are recorded on a rotating disk and the images are played back using a separate television system or printer.

Since such electronic still cameras cannot use high-sensitivity film like conventional still cameras, it is desirable to use a strobe as an auxiliary light source.

However, charging to drive the strobe requires a large current, which causes various problems such as battery voltage fluctuation and electrical noise. Especially,
In an electronic still camera, unlike a normal still camera, it is necessary to record on a magnetic disk after exposing a solid-state image sensor, so it is not preferable to supply charging radio waves to a strobe during this recording. In other words, in electronic still cameras, it is necessary to stabilize the power supply voltage and take better measures against noise, thereby minimizing the influence of strobe charge-up on imaging and recording operations.

OBJECTS OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and the present invention is an electronic still camera that eliminates the effects of strobe charge-up and enables smooth imaging and recording. Our goal is to provide the following.

Structure of the Invention The above-mentioned object is achieved by an electronic still camera configured to first record an image signal generated by exposure to an image sensor on a magnetic disk, and then charge up a strobe.

See the drawing below! ＠、Detailed explanation of the present invention will be given below.

Embodiment of the Invention FIG. 1 shows an embodiment of an electronic still camera, particularly an electronic still camera with a built-in strobe, to which the present invention is applied.

In this figure, 2A and 2B are lenses, 4 is an aperture mechanism, 6 is a received light amount sensor, 8 is a focal plane shutter, and 10 is a viewing amount control circuit that controls each of these mechanisms 4, 6.8, etc. 12 is an image sensor consisting of an image sensor such as a COD, 14 is an image sensor drive circuit that sends out a large image sensor drive signal 5ENS for reading out video signals from the image sensor 12, and 16 is an image sensor 1
18 is a signal recording circuit that sends out a signal to record the video signal sent out from 2 on a magnetic disk OK; 18 is a base signal v;
20 is a recording timing control circuit that sends out a recording timing control signal RFC, etc., 22 is an amplifier, and 24 is a recording head. 26 is a PC detection coil for detecting a PG pin (not shown) for generating a phase signal embedded in the magnetic disk; 28
is a buffer amplifier for obtaining the phase detection signal PG of the magnetic disk DK. 30 is a DC motor that rotates the magnetic disk OK, 32 is a frequency 49 generator that sends out a signal corresponding to the rotational speed of the DC motor 30, and 34 is the DC motor 3.
This is a servo circuit for controlling 0.

Reference numeral 36 is a battery built into the camera, and reference numeral 38 is a stabilizing circuit for supplying a stabilizing voltage to each prong, including circuit blocks not shown in the figure. Reference numeral 40 is an innovator for inverting the level of the recording timing control signal RFC described above, and reference numeral 42 is a differentiation circuit that sends out a trigger pulse DEF in synchronization with the rising edge of the input signal. Further, RB is a release button equipped with two-stage switches Sl and S2, in which the first switch St is closed in the first stage of depression, and the second switch S2 is closed in the second stage. Then, the release signal REL is sent out by opening the second switch S2. 44 is a flip-flop, which inverts its output level in response to two series of trigger pulses DEF and release signal REL.

4B is an OR gate, 48 is a booster circuit that converts the voltage of the battery 36, 50 is a strobe charging circuit, 52 is a charging voltage detection circuit, 54 is a circuit, 56 is an arc tube, and 58 is when the base potential is at a low level. This is a closed PNP type transistor switch.

2nd B? 1(A) to (0) are timing diagrams illustrating the operation of FIG. 1.

Here, (A) and (B) in the same figure show the relay release button RB.
The operating states IjJ of the first switch S1 and the second switch S2 are shown in conjunction with the depressing operation of the push button 17.

FIG. 2C shows the throttle operation of the throttle mechanism 4 performed in conjunction with the closing of the second switch S2.

FIG. 2D shows the front curtain and rear curtain operations of the focal plane shutter 8.

(E) shows the strobe trigger signal TRIG sent from the exposure control circuit 10, which is a normal X
This corresponds to the Ni point.

FIG. 2F shows a trailing curtain operation completion signal sent from the exposure control circuit 10.

In addition, the same figure (G) shows the timing at which the flash tube 56 of the strobe emits light, the same figure (H) shows the reference signal vP sent out from the reference signal generation circuit 18, and the same figure (I) shows the timing from which the strobe light emitting tube 56 emits light. (J) shows the reference phase detection signal PC sent out, (J) shows the image sensor drive signal 5ENS sent out from the image sensor drive circuit I4, and (K) shows the recording timing control signal sent out from the recording timing control circuit 20. Signal R
FC, (L) in the same figure shows the signal RFC sent from the inverter 40, and (M) in the same figure shows the output signal of the differentiating circuit 42.

(N) in the figure is a signal that controls activation/stop of the booster circuit 48 and shows the base potential of the transistor 58. That is, when a low level is applied to its base, transistor 58 conducts and the urn! The pressure circuit 48 is connected to the battery 3
Connected to 6. On the other hand, when the base of the transistor 58 is at a high level, the transistor 58 is cut off and the operation of the booster circuit 48 is stopped.

(0) in the figure shows the charging voltage of the charging circuit 52. and,
When the charging voltage reaches a predetermined value, the detection circuit 52 sends a high level detection signal VDET to the OR gate 46.

Next, the operation of this embodiment will be explained with reference to FIGS. 1 and 2.

(2) When the second switch S2 is closed by pressing down the release button RB, the release signal REL signal (high level) is applied to one input terminal of the flip-flop 44, as shown in FIG. 2(B).

As a result, a high level signal is sent out from the flip-flop 44 and applied to the base of the transistor 58 via the OR gate 46. Therefore, transistor 58
is turned off, and the operation of the A pressure circuit on the 4th is stopped.

■ After that, the aperture state of the diaphragm 4 is set (see Figure 2 (
See C). Reference phase detection signal PG sent out after that
The image sensor drive signal 5ENS exhibits a low level in synchronization with the image sensor 12 for image formation.
enters standby state. Then, when the shutter 8 is fully opened, the strobe trigger signal TRIG is sent out from the exposure control circuit IO (see FIG. 2(E)). A strobe is emitted in synchronization with this strobe trigger signal T[G (see FIG. 2 (G)), and image information is accumulated on the image sensor 12.

(2) When the rear curtain of the focal plane shutter 8 is closed, a rear curtain operation completion signal (see FIG. 2(F)) is sent from the exposure control circuit 10, and imaging is completed.

The image sensor drive signal 5ENS exhibits a high level in synchronization with the reference phase detection signal PG sent out after this imaging. In synchronization with this, a recording timing control signal REG is sent out. In this way, a video signal is read from the image sensor 12 and written to the magnetic disk OK. During this writing period, a high-level voltage remains applied to the base of the transistor 58 ((N)in@ in FIG. 2). Therefore, the transistor 58 is in a cut-off state, and charging current to the strobe is not yet supplied.

(2) At the falling edge of the recording timing control signal RFC, a trigger pulse DEF is sent from the differentiating circuit 42. Therefore, the output level of the free amplifier 44 is inverted and becomes a low level. At this time, since the charging circuit 5o is in a discharging state, the charging voltage detection circuit 52 sends out a low level detection signal VDET. In this way, since the two signals introduced into the OR gate 46 both exhibit a low level, the output of the OR gate 48 becomes a low level (Fig. 2 (N) q). Thus, the l transistor 58 becomes conductive and charging begins.

(2) Then, when a predetermined charging voltage value is reached, the construction detection signal VDET becomes high level.

Therefore, the transistor 58 is also cut off via the OR gate 46, and the operation of the booster circuit 4 is stopped (1-).

In the following explanation, press I7 of release button RB
The strobe charging operation is stopped from the lower illumination point to the end of image writing to the recording medium. In this case, for example, the completion of the aperture operation or the shutter operation may be detected.

Furthermore, although the above embodiments have been described using an electronic still camera with a built-in strobe as an example, the present invention is not necessarily limited to this; for example, an electronic still camera with a built-in strobe may be used. . This type of electronic still camera is particularly effective when the camera and strobe are driven using a common power source. In short, it is only necessary to prohibit the strobe charging operation during the period from the accumulation of image signals in the image sensor of the camera to the end of recording on the recording medium.

Effects of the Invention As described above, the electronic still camera according to the present invention can be configured to stop charging up the strobe during the period from the start of image signal accumulation to the end of recording. drop in power supply voltage,
This has the advantage of being able to eliminate the effects of noise generation.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a 411 electronic still camera with a built-in strobe according to an embodiment of the present invention, and FIG.
0) is a timing diagram for explaining the operation of FIG. 1. 2A, 2B...Lens, 4...Aperture, 6...Light receiving amount sensor, 8...Shutter, 10...Exposure control circuit, 12...Image sensor, 14...Image sensor Drive circuit, 16... Signal recording circuit, 18... Reference signal generation circuit, 20... Recording timing control circuit, 22... Amplifier, 24... Recording head, 28-F (= Edahata coil , 28...Buffer amplifier, 30...W motor, 32...Frequency generator, 34...Servo circuit, 36...Battery, 38...Stabilization circuit, 40...Inverter , 42... Differentiation circuit, 44... Flip-flop, 46... OR gate, 48... Boost circuit, 50... Charging circuit, 52... Charging voltage detection circuit, 54... Trigger circuit , 56... Arc tube, DK... Magnetic disk, RB... Release button.

Claims (1)

[Claims] In an electronic still camera configured to store image information obtained from an image sensor in a recording medium, a first means detects a time point at which image capturing to the image sensor starts and sends a first signal;
Detecting the end point of writing the image onto the recording medium, and detecting the second
An electronic still comprising: a second means for transmitting a signal; and a control means for stopping a strobe charging operation from when the first signal is transmitted until when the second signal is transmitted. camera.