JPH073533B2 - 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 in which a photoelectric conversion element (for example, CCD) is used to convert an optical image into an electric signal by photoelectric conversion and the electric signal is magnetically recorded.

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, and then the exposure value is corrected based on the accuracy information from the CCD, and then exposure is performed again (main exposure). ) System AE system has been devised.

FIG. 3 is a block diagram of an exposure control system in such an electronic camera, in which the object 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.

This kind of problem also occurs when using a digital camera equipped with a shutter to handle movies, and one of the shutter blades must be kept energized when the shutter is held open. Power consumption is higher than in the case of exposure.

[Means for Solving Problems] An object of the present invention is to provide a camera that solves the above problems, and for that purpose, a first optical device is interposed in the optical path of an optical image to block the optical path. A first shutter biased to a position, a first shutter drive means for driving the first shutter to a second position for opening the optical path, and a second shutter biased to a third position for opening the aperture. In a camera having a shutter and a second shutter drive means for driving the second shutter to the first position that blocks the optical path, the first shutter is locked to the second shutter and Shutter holding means that can be held at a position, and electromagnetic driving means that locks the shutter holding means with the first shutter in conjunction with movement of the first shutter to the second position by the first shutter driving means. And before The second shutter and the shutter holding means are provided, and with the movement of the second shutter to the first position by the second shutter driving means, the first shutter and the shutter holding means It is characterized in that it comprises an engagement releasing means capable of releasing the engaged state.

[Operation] In the case of performing pre-exposure or in the case of a movie, the first shutter drive means is operated to move the first shutter to the second position, and the electromagnetic drive means is interlocked with the first shutter drive means. After engaging the shutter holding means with the first shutter by means of, the operation of the first shutter drive means and the electromagnetic drive means is stopped. This mechanically holds the first shutter in the second position. Further, the second shutter drive means is stopped to urge the second shutter to the third position to keep the optical path open.

In the case of the main exposure, both the first shutter driving means and the second shutter driving means are operated to move the first shutter to the second position and move the second shutter first.
At this time, with the movement of the second shutter to the first position, the engagement state between the first shutter and the shutter holding means is released by the engagement releasing means. Then, in this state, the second shutter drive means is stopped, the second shutter is returned to the third position, the optical path is opened, and exposure is started. Then, after a predetermined time, the first shutter driving means is stopped, the first shutter is returned to the second position, and the optical path is closed.

[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. During pre-exposure and main exposure, a book as described later (FIG. 4) is shown. The electromagnetic devices as the first shutter driving means and the second shutter driving means of the invention rotate counterclockwise to charge the springs 1A and 2A. Both blades 1 and 2 have engaging pins 7 and 8 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 11 is opened, and the engagement pin 8 of the first shutter blade 1 is locked.
The lock release lever 4, the lever 5 and the like function as the shutter holding means of the present invention. The lock release lever 4 releases its lock and functions as the engagement release means of the present invention together with the engagement pin 7 of the second shutter blade 2. Both levers 3 and 4 are biased clockwise by springs 3A and 4A, respectively. Further, each lever 3 and 4 is interlocked with levers 5 and 6. The lever 5 is biased in the counterclockwise direction by a spring 5A, and has an engaging pin 9 at its rotating end. Reference numeral 10 denotes an electromagnet, which is turned clockwise by pulling one end of the lever 6 when energized. The engaging pin 9 of the lever 5, the lever 6, the electromagnet 10, etc.
It constitutes the electromagnetic drive means of the present invention.

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 is kept closed with respect to the aperture 11, and at this time, the engagement pins 7 and 8 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. As a result, the spring 1A is charged and the aperture 11 is opened. Before and after this operation, electromagnet 10
Is energized to rotate the lever 6 clockwise, which pushes the engagement pin 9 of the lever 5 clockwise. As a result, the first protrusion 5B of the lever 5 pushes the protrusion 3B of the locking lever to rotate the lever 3 counterclockwise, and at the same time, the second protrusion 5C of the lever 5 causes the first step of the locking release lever 4 to move. Moving from the portion 4B to the second step portion 4C, the lever 4 is rotated and locked, and the rotating end portion is brought close to the engagement pin 7 of the second shutter blade 2. This state is shown in FIG. In this state, even if the electromagnet 10 is returned to the non-energized state and the electromagnetic device of the first shutter blade 1 is turned off, the second protrusion 5C of the lever 5 is moved to the second step portion 4C of the lock release lever 4. Since it is locked, rotation of the lever 5 in the counterclockwise direction is blocked, and the engagement pin 8 of the first shutter blade 1 and the locking lever 3 are locked.
As a result of maintaining the engagement state with the aperture 11, the aperture 11 is held in the open state.

After that, pre-exposure CCD as an image sensor (not shown)
Then, the optimum aperture value and shutter speed are determined, and for the main exposure based on the determined values, the second shutter blade 2 is energized and the shutter 2 is rotated counterclockwise (note that Prior to this rotation, the first shutter blade 1 is energized and held at the position shown in FIG. 2 (the position where the aperture 11 is opened) to charge the spring 1A). In the middle of the rotation, the engagement pin 7 pushes the rotation end portion of the lock release lever 4, and as a result, the second pin of the lever 5 is pushed.
The protrusion 5C moves from the second step portion 4C of the lever 4 to the first step portion 4B and the lever 5 rotates counterclockwise. At the same time, as the first protrusion 5B rotates, the protrusion 3B engaged with the protrusion 5C reverses. By rotating in the clockwise direction, the rotating end portion of the locking lever 3 rotates in the clockwise direction to unlock the engagement pin 8 and reach the position shown in FIG. Then, after the rotating second shutter blade 2 is positioned at a predetermined position (position for closing the aperture 11),
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 the movie, the first shutter blade is stopped and held by the mechanical means to keep the aperture in the open state, 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. 4 is a block diagram of a circuit for controlling the shutter shown in FIGS. 1 and 2. In this figure,
Reference numeral 51 is an image pickup element, 201 is a control circuit, which has a CPU, a RAM, and a ROM storing a 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 speed 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, 212 is an aperture control mechanism, and 213 is an exciting circuit.

5 and 6 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. 4 and 5.

First, press the release button in the 1st step to switch to the 10th switch.
When 214 is closed (step S1 in FIG. 5), the control circuit 201 activates the image sensor drive circuit 203 and the aperture value determination circuit 210 (step S2 in FIG. 5). 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 groove 212 of the same machine is compared with the diaphragm device by the determined diaphragm value A.
preset v.

Next, the control circuit 201 waits for a certain period of time t ₁ required for the aperture preset operation (step S3 in FIG. 5), and then the second switch 215 that is turned on by pressing the second step of the release button is closed. It is checked whether or not it has been done (step S4 in FIG. 5).

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. 5), and then performs operations such as retraction of the mirror and aperture stop.

Then, 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. 5), and then commands the exciting circuit 213 to give a small time to the electromagnet 10. Energize (Fig. 5, steps S7, S
8) Then, the power supply to the electromagnet 217 is stopped (step S9 in FIG. 5). During this energization period t ₂ , the first shutter blade 1 rotates counterclockwise (counterclockwise) and is locked by the rotating end portion of the locking lever 3 by the operation of the lever 6 which is then rotated by the electromagnet 10. Is enough time. Thus the aperture
11, the image sensor 51 is exposed (pre-exposure), and the control circuit 201 activates the correction circuit 209 at this point (step S10 in FIG. 5).

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 Y level of the luminance signal from the signal processing circuit 204 to which the image pickup signal from 1 is input, and this is output to the shutter time setting circuit 205 as a correction signal. As a result, the shutter speed setting circuit 205
Replaces the initially set shutter speed (manually or the like) with the shutter speed from the correction circuit 209.

After step S8, the control circuit 201 waits for a fixed period t ₃ sufficient for such operation (step S11 in FIG. 5), and the correction circuit 2
The output at that time is stored in 09 (Fig. 5, step S1
2). Then, the excitation circuits 207 and 208 are instructed to energize the electromagnets 217 and 218 (step S13 in FIG. 5). As a result, the second shutter blade 2 is turned counterclockwise (counterclockwise) to close the aperture 15, and both blades 1 and 2 resist the respective springs 1A and 2A and the electromagnet 21.
This state is maintained by 7 and 218.

Next, the control circuit 201 triggers the shutter control circuit 206 (step S14 in FIG. 5). As a result, the shutter control circuit 206 causes the vertical synchronization signal (V
In response to d), the energization of the electromagnet 218 by the excitation circuit 208 is stopped, and the second shutter blade 2 is made to travel (clockwise). 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 217 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 S15 in FIG. 5), the control circuit 201 stops the operation of the circuits 202, 209 and 210 (step S16 in FIG. 5) and ends the operation.

FIG. 6 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 when the release button is pressed in the second step (step S24), the control circuit 201
Excites electromagnet 217 for t ₂ period (step S25), then instructs excitation circuit 213 to energize electromagnet 10 for a very short time (steps S26, S27), and thereafter stops energization to electromagnet 217 (step S28). . As a result, the first shutter blade 1 is rotated counterclockwise (counterclockwise), and the lever 6 rotated by the electromagnet 10 is moved to move the first end of the first shutter blade 1 to the rotating end portion of the locking lever 3 similarly to the operation during still recording. (1) The shutter blade 1 (pin 8 thereof) is locked, and the aperture 11 is held open. In this way, the subject light can be made incident on the image pickup element through the aperture 11 having the opening, and a movie can be picked up.

When the release button second-stage switch 215 is turned off (step S29), the electromagnet 218 is excited for a very short time (steps S30, S31), whereby the second shutter blade 2 closes the aperture 11. Rotate to
Along with this rotation, the engagement pin 7 pushes up the rotation end 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 8 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 S32), the image sensor drive circuit 2
The operation of 03 and the aperture value determination circuit 210 is stopped.

Although the embodiment described so far is an electronic camera applied to the present invention, a normal film is used.
Of course, the present invention can be applied to an eye flex camera.

[Effects of the Invention] As described above, according to the camera of the present invention, a shutter holding unit that can be locked to the first shutter to hold the first shutter at the second position where the optical path is opened, and the first shutter. An electromagnetic drive unit that locks the shutter holding unit with the first shutter in association with the movement of the first shutter to the second position by the driving unit, and the second shutter and the shutter holding unit are provided. A simple structure is provided because an engagement releasing means that can release the engagement state between the first shutter and the shutter holding means is provided along with the movement of the second shutter to the first position that blocks the optical path by the shutter driving means. In addition, it is possible to obtain a camera having a shutter that operates with low power consumption.

[Brief description of drawings]

1 and 2 are exploded structural views showing one embodiment of a shutter portion of an electronic camera to which the present invention is applied, FIG. 3 is a block diagram showing a schematic structure of the present embodiment, and FIG. 4 is this embodiment. FIG. 5 is a block diagram showing the electric control system of FIG. 5, and FIG. 5 and FIG. 6 are flowcharts showing examples of control procedures to be executed by the control circuit shown in FIG. 3 ... Locking lever, 4 ... Locking release lever, 5,6 ... Lever, 7,8,9 ... Engaging pin, 10 ... Electromagnet.

 ─────────────────────────────────────────────────── ─── 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. Inside the Tamagawa Plant (56) References: Showa Sho 59-33028 (JP, U)

Claims (1)

[Claims] 1. A first shutter interposed in the optical path of an optical image and biased to a first position for blocking the optical path; and a first shutter for driving the first shutter to a second position for opening the optical path. A first shutter drive means, a second shutter biased to a third position for opening the aperture, and a second shutter drive means for driving the second shutter to the first position blocking the optical path. In the camera, shutter holding means that can be locked to the first shutter and hold the first shutter at the second position; and the first shutter to the second position by the first shutter driving means. Electromagnetic drive means for locking the shutter holding means to the first shutter in conjunction with movement of the second shutter, the second shutter and the shutter holding means, and the second shutter driving means. A camera comprising: an engagement releasing means capable of releasing the engagement state of the first shutter and the shutter holding means with the movement of the second shutter to one position.