JPH073532B2 - camera - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shutter mechanism in a camera, for example, a camera provided with a means for locking a shutter blade at a specific position and further releasing the locking. is there.

[Prior Art] In recent years, a so-called electronic camera has been developed which uses a photoelectric conversion element (for example, a CCD) to convert subject light into an electric signal by photoelectric conversion and magnetically records the electric signal.

In such automatic exposure (AE) of an electronic camera, a highly accurate AE system is required because the dynamic range of a photoelectric conversion element (CCD) as an image pickup element is narrow. Therefore, as in the case of a silver halide camera, it is also possible to measure the subject brightness with a light receiving element such as an SPC and determine the optimum aperture value or shutter speed based on the output value. Then, it is difficult to realize a high-precision AE system due to the difference in the photosensitivity between the SPC and CCD and the difference in the dynamic range. Therefore, exposure is performed once with the aperture value or shutter speed determined based on the SPC information (preliminary exposure), the aperture value or shutter speed is corrected based on the brightness information from the CCD, and then exposure is performed again (this An exposure type AE system has been devised.

FIG. 4 is a block diagram of an exposure control system in such an electronic camera, in which the subject light is measured by a photometric system 30 including a light receiving element such as an SPC, and its output value and input of a lens used, a set shutter speed, etc. The arithmetic circuit 32 once determines the optimum AE control amount based on the information from the input information circuit 31 in which the information is set, and the control circuit 33 based on this determined value.
In controlling the aperture control system 34 and the shutter control system 35,
After setting the aperture value and shutter speed, the same control circuit
The shutter is opened by 33, and the image pickup circuit 36 (CC
D) is used for pre-exposure, the brightness information from the circuit 36 is input as correction information to the arithmetic circuit 32, the control values of the control systems 34 and 35 are corrected by the circuit 32, and then the control circuit 3
Under the control of 3, main exposure is performed, and the image pickup signal from the image pickup circuit 36 is converted into a format suitable for magnetic recording in the recording circuit 37 and recording is performed.

When performing pre-exposure with an image sensor such as a CCD, the shutter must be closed for the purpose of protecting the image sensor such as a CCD during non-exposure.
It is necessary to keep the shutter open during the pre-exposure.

[Problems to be Solved by the Invention] However, in an electronic camera equipped with the exposure control system as described above, for example, when a focal plane shutter is used and its driving is performed by using an electromagnetic force, preliminary exposure is performed. Until the end, the first shutter blade (rear blade) must be kept energized in order to open the shutter, which is not preferable in terms of power consumption.

In addition, since the shutter has to be opened when a movie is supported, power consumption increases in a device that drives the shutter using the electromagnetic force as described above, which is not practical.

[Means for Solving Problems] An object of the present invention is to provide a camera that solves the above problems, and for that purpose, the first and the first members are independently biased in the same direction. 2 shutter blades, and locking means for mechanically locking the first shutter blades in the driving position when the first shutter blades are driven in a direction against the bias. And a release means for mechanically releasing the locking by the locking means based on the movement of the second shutter blade when the second shutter blade is driven in the direction against the bias. It is characterized by having

[Operation] In the present invention, the first shutter blade is locked when the first shutter blade is driven in the specific direction, and this locking is released as the second shutter blade travels.

[Examples] Hereinafter, the present invention will be described in detail based on Examples.

1 and 2 show an embodiment of a shutter portion of an electronic camera according to the present invention. FIG. 1 shows the initial state before exposure, and FIG. 2 shows the state during preliminary exposure.

In both figures, reference numerals 1 and 2 denote first and second shutter blades, which are urged clockwise by springs 1A and 2A, respectively, as will be described later (FIG. 4) during pre-exposure and main exposure. The electromagnetic device rotates counterclockwise to charge the springs 1A and 2A. Both blades 1 and 2 have engaging pins 12 and 13 which engage with one ends of a locking lever 3 and a locking release lever 4, respectively, which will be described later.
Both shutter blades 1 and 2 are rotated counterclockwise by an electromagnetic device in response to an operation of a release button (not shown; detailed operation will be described later) that performs a two-step pressing operation.

The locking lever 3 locks the first shutter blade 1 at a position where the aperture 15 is opened. The lock release lever 4 releases the lock. Both levers 3 and 4 are biased clockwise by springs 3A and 4A, respectively. Also, each lever 3,4
Interacts with levers 5 and 6. The lever 5 is biased counterclockwise by a spring 5A, and has an engaging pin 14 at its rotating end. Reference numeral 11 is a reflection mirror, 8 is a rotatable return lever for retracting the reflection mirror 11 from the finder optical path, and 8A is a spring for urging the lever 8 counterclockwise. A narrowing lever 9 controls a narrowing mechanism (not shown).

Next, the operation will be described.

In the state shown in FIG. 1, the first shutter blade 1 and the second shutter blade 1
The shutter blade 2 maintains an open state with respect to the aperture 15, and at this time, the engagement pins 12 and 13 are engaged with each other.
It is in a position that does not engage with 3 and 4.

First, prior to the preliminary exposure, the first shutter blade 1 is rotated counterclockwise and held by the driving of the electromagnetic device. By this, the spring 1A is charged and the aperture 15 is opened. A mirror 11 supported by a lever 16 which is rotatable before and after this operation rotates the lever 8 clockwise by an external force (not shown) (for example, the rotational force of a motor is transmitted to the lever 8 via a cam or a lever). By moving, it rotates clockwise and retracts so as to be out of the finder optical path. At the same time, the lever 7 is rotated counterclockwise. This causes the lever 7 to rotate the lever 6 clockwise, and the rotation of the lever 6 pushes the engagement pin 14 of the lever 5 clockwise.

As a result, the first protrusion 5B of the lever 5 is the protrusion of the locking lever 3.
3B is pushed to rotate the lever 3 in the counterclockwise direction, and at the same time, the second projection 5C of the lever 5 causes the first step portion of the lock release lever 4 to move.
Moving from 4B to the second step portion 4C, the lever 4 is rotated and locked, and the rotating end portion is engaged with the engagement pin of the second shutter blade 2.
Get closer to 12. This state is shown in FIG. At this time, the first shutter blade 1 is de-energized to lock the engagement pin 13 to the pivoting end of the locking lever 3, thus keeping the aperture open.

After that, pre-exposure CCD as an image sensor (not shown)
Then, the optimum aperture value and shutter speed are determined, and in order to perform the main exposure based on the determined values, the second shutter blade 2 is energized to rotate the shutter 2 counterclockwise (note that Prior to this rotation, the first shutter blade 1 is energized to move it to the position (aperture 15) shown in FIG.
To the position where it is released) to charge spring 1A). During the rotation, the engagement pin 12 pushes the rotation end of the lock release lever 4 so that the second protrusion 5C of the lever 5 moves from the second step 4C to the first step of the lever 4. 4B, the lever 5 rotates counterclockwise, and at the same time, the first protrusion 5B
As the projection 3B engaged with this rotates in the counterclockwise direction, the rotation end of the locking lever 3 rotates in the clockwise direction to release the locking of the engagement pin 13, and The position shown in Fig. 1 is reached. Then, after the rotating second shutter blade 2 is positioned at a predetermined position (position for closing the aperture 15),
When the energization is turned off, the second shutter blade 2 is rotated clockwise by the spring 2A. Then, when the energization of the first shutter blade 1 is turned off after the elapse of the set time, the first shutter blade 1 becomes the second shutter blade 1. The shutter blade 2 is rotated while forming a slit between the shutter blade 2 and main exposure is performed on the image pickup device (CCD), and both shutter blades 1 and 2 return to the positions shown in FIG.

As described above, during the pre-exposure or during the movie, the aperture is kept in the open state by stopping and holding the first shutter blade by the mechanical means, so that the power consumption can be reduced. Further, at the time of main exposure, low power consumption can be realized by using electromagnetic force to stop and hold the first shutter blade and release it in response to the rotation of the second shutter blade.

FIG. 3 is a diagram for explaining another embodiment of the present invention. In the figure, 10 is a lever for rotating the lever 7 in conjunction with the narrowing lever 9. However, the return lever 8, the lever 16 and the mirror 11 are omitted in this figure.

In the embodiment described with reference to FIGS. 1 and 2, the rear blade 1 is locked in the open state in conjunction with the retracting operation of the mirror, but in the embodiment shown in FIG. The lever 7 is rotated counterclockwise (counterclockwise) in conjunction with the movement or rotation of the.

That is, the rotation of the narrowing lever 9 at the time of narrowing causes the lever 10 to rotate clockwise (clockwise), and thus the lever 7 to rotate counterclockwise (counterclockwise). The following operation is the same as that of the above-described embodiment, and locks and holds the first shutter blade 1.

As an electromagnetic drive device for the first shutter blade 1 and the second shutter blade 2, for example, it is preferable to mount a coil on the surface of these blades and generate an electromagnetic force between them and a permanent magnet (not shown). is there. Alternatively, it is also possible to mount a simple electromagnet and drive these shutter blades.

FIG. 5 is a block diagram of a circuit for controlling the shutter shown in FIGS. 1, 2, and 3.

The reference numerals of the main parts in this figure will be described below. Reference numeral 51 is an image sensor, 201 is a control circuit, which has a CPU, a RAM, and a ROM storing the control procedure as shown in FIG.

202 is an SSG (synchronization signal generator), 203 is an image sensor drive circuit, 204 is a signal processing circuit, 205 is a shutter time setting circuit, 206 is a shutter control circuit, 207 and 208 are excitation circuits, and 210 is an aperture value determination. A circuit, 211 is a photometric element, and 212 is an aperture control mechanism.

6 and 7 are flowcharts showing the control procedure to be executed by the control circuit 201 shown in FIG.

The control procedure at the time of still recording in this embodiment will be described below with reference to FIGS. 5 and 6.

First, the first switch of the release button
When 214 is closed (step S1 in FIG. 6), the control circuit 201 activates the image sensor drive circuit 203 and the aperture value determination circuit 210 (step S2 in FIG. 6). This allows the image sensor 5 to synchronize with the timing signal from the SSG (synchronization signal generator) 202.
While the driving of 1 is started, the aperture value determination circuit 210 controls the object brightness information Bv from the photometric element 211 and the shutter speed setting circuit 205.
The appropriate aperture value Av is determined based on the shutter speed information Tv from (4) and is output to the aperture control mechanism 212. Then, the mechanism 212 causes the diaphragm device to determine the aperture value A
preset v.

Next, the control circuit 201 waits for a fixed period t ₁ necessary for the aperture preset operation (step S3 in FIG. 6), and then the second switch 215 that is turned on by pressing the release button in the second stage is closed. It is checked whether or not it has been done (step S4 in FIG. 6).

As a result, if the switch 215 is closed, the control circuit 2
01 causes the aperture value determination circuit 210 to store the aperture value Av at that time (step S5 in FIG. 6), and then performs operations such as retraction of the mirror and aperture stop.

Next, the control circuit 201 commands the first shutter blade electromagnet exciting circuit 207 to energize the electromagnet 221 for a certain period of time t ₂ (step S6 in FIG. 6), and when the time t _{2 has} elapsed, the electromagnet 22
The power supply to 1 is stopped (step S7 in FIG. 6). In the energization period t ₂ , the first shutter blade 1 rotates counterclockwise (counterclockwise), and then the return lever 8 and the lever 7 are rotated by the rotation of the lever 6. The time is sufficient for the first shutter blade 1 to be locked in the section. Thus, the aperture 11 is opened, the image pickup element 51 is exposed (pre-exposure), and the control circuit 201 activates the correction circuit 209 at this point (step S in FIG. 6).
8).

Here, in this state, the aperture is first determined by the aperture value determination circuit 210.
Since the aperture value is determined by the aperture value Av determined by the correction circuit 209, the correction circuit 209 sets the image pickup device 5 exposed in the actual aperture state.
The proper shutter time is determined based on the level of the luminance signal Y from the signal processing circuit 204 which inputs the image pickup signal from 1.
This is output to the shutter time setting circuit 205 as a correction signal. As a result, the shutter time setting circuit 205 replaces the shutter time initially set (by hand or the like) with the shutter time from the correction circuit 209.

After step S8, the control circuit 201 waits for a certain period t ₃ sufficient for such operation (step S9 in FIG. 6), and the correction circuit 20.
The output at that time is stored in 9 (step S10 in FIG. 6).
Then, for the excitation circuits 207 and 208, the electromagnets 221 and 2
The power supply to 22 is commanded (step S11 in FIG. 6). As a result, the second shutter blade 2 is rotated counterclockwise (counterclockwise) to close the aperture 15, and both blades 1 and 2 are kept in this state by the electromagnets 221 and 222 while resisting the respective springs 1A and 2A. To do.

Next, the control circuit 201 triggers the shutter control circuit 206 (step S12 in FIG. 6). As a result, the shutter control circuit 206 causes the vertical synchronization signal (V
In response to d), the energization of the electromagnet 222 by the excitation circuit 208 is stopped, and the second shutter blade 2 is made to travel (clockwise direction). After that, the previously corrected shutter time obtained from the shutter time setting circuit 205 is counted, and at that time point, the energization of the electromagnet 221 by the excitation circuit 207 is stopped and the first shutter blade 1 is moved ( Clockwise).

In this way, the proper exposure (main exposure) of the image sensor 51 is performed, and the image information formed by this exposure is read in synchronization with the next vertical synchronization signal Vd and processed by the signal processing circuit 204. . Then, a so-called 1-field television signal is recorded on a magnetic disk or the like.

After that, when the first switch 214 is turned off (step S13 in FIG. 6), the control circuit 201 stops the operation of the circuits 202, 209 and 210 (step S14 in FIG. 6) and ends the operation.

FIG. 7 is a flowchart showing a control procedure when the electronic camera is used in the movie mode.

First, when the mode switch 216 is turned off (opened) and the movie mode is set, the control circuit 201 responds to the switch 214 being turned on (step S21) from the shutter time setting circuit 205 by Tv = 1/60 ( Second) signal is output (step S
22), and at the same time, operate the image sensor drive circuit 203 and the aperture value determination circuit 210 (step S23).

Then, in response to the switch 215 being turned on in response to the second-step depression of the relays button (step S24), the control circuit 201
Excites electromagnet 221 for t ₂ period (step S25). As a result, the first shutter blade 1 is driven to the rotating end portion of the locking lever 3 by driving the first shutter blade 1 in the same manner as in the still recording operation by rotating the return lever 8, the lever 7, and the lever 6.
(Pin 13) is locked and the aperture 15 is held open. Thereafter (t ₂ after), cut off the power supply to the electromagnet 221 (step S26). In this way, the subject light can be made incident on the image pickup device through the aperture 15 that is opened, and movie shooting can be performed.

When the release button second-stage operation switch 215 is turned off (step S27), the electromagnet 222 is excited for a minute time (steps S28, S29), whereby the second shutter blade 2 closes the aperture 15. Rotate to
Along with this rotation, the engagement pin 12 pushes up the rotation end portion of the lock release lever 4 and unlocks the lever 5. As a result, the rotating end of the locking lever 3 unlocks the engagement pin 3 and unlocks the first shutter blade 1. Therefore, both shutter blades 1 and 2 are springs 1A and 2A.
Returns to the initial state (see FIG. 1).

After that, when the switch 214 for the first-stage operation of the release button is turned off (step S30), the image sensor drive circuit 2
The operation of 03 and the aperture value determination circuit 210 is stopped.

Although the embodiments described so far are the ones in which the present invention is applied to an electronic camera, a normal film is attached.
Of course, the present invention can be applied to an eye reflex camera.

[Effects of the Invention] As described above, according to the present invention, it is possible to obtain a camera having a shutter having a simple configuration and operating with low power consumption.

[Brief description of drawings]

1 and 2 are exploded structural views showing an embodiment of a shutter portion of an electronic camera to which the present invention is applied, and FIG. 3 is an exploded view showing another embodiment of a shutter portion of an electronic camera to which the present invention is applied. Configuration diagram, FIG. 4 is a block diagram showing a schematic configuration of an electronic camera, FIG. 5 is a block diagram showing an electrical control system of the present embodiment, and FIGS. 6 and 7 are control circuits shown in FIG. 3 is a flowchart showing an example of a control procedure to be executed by each. 3 ... Locking lever, 4 ... Locking release lever, 5,6,7,10 ... Lever, 8 ... Return lever, 9 ... Squeezing lever.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Shuichiro Saito 770 Shimonoge, Takatsu-ku, Kawasaki-shi, Kanagawa Canon Inc., Tamagawa Plant (72) Inventor Yukio Ogawa 770 Shimonoge, Takatsu-ku, Kawasaki-shi, Kanagawa Canon Inc. In Tamagawa Works (56) Reference JP-A-60-103873 (JP, A) JP-A-53-71831 (JP, A) JP-A-62-128675 (JP, A)

Claims (1)

[Claims] 1. A first and a second shutter blade independently biased in the same direction, and when the first shutter blade is driven in a direction against the bias, A locking means for mechanically locking the first shutter blade in the drive position, and a second shutter blade when the second shutter blade is driven in a direction against the bias. A camera, comprising: a releasing means for mechanically releasing the locking by the locking means based on a movement.