JP2624645B2 - camera - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a camera that consumes less power while a shutter is kept open.

[Related Art] In recent years, an electronic camera that converts an optical image into an electric signal using a photoelectric conversion element (CCD) and magnetically records the electric signal has been developed.

In the automatic exposure mechanism (AE) of this type of camera, due to the narrow dynamic range of the CCD,
A highly accurate AE system is required. As a control method for this purpose, a method is known in which the brightness of a subject is measured by a light receiving element such as an SPC and the optimum aperture value or shutter speed is determined based on the output value, as in the case of a silver halide camera.

However, it is difficult to realize a highly accurate AE system due to a difference in light receiving sensitivity and a difference in dynamic range between the SPC and the CCD.

Therefore, as shown in FIG. 7, exposure is performed once based on the aperture value and the shutter speed determined based on the information from the SPC (preliminary exposure), and the aperture value and the shutter speed are determined based on the manual flow rate information obtained from the CCD. An AE system has been proposed in which the speed is corrected and then the exposure (main exposure) is performed again. That is, the output data of the input information source 502 that measures the subject brightness by the photometric system 500 using a light receiving element such as an SPC and sends input information such as the lens to be used and the set shutter speed, and the output data of the photometric system 500. Is introduced into the arithmetic circuit 504, whereby the optimum AE control amount is determined. And
After the control circuit 506 controls the aperture value, the shutter speed, and the like, the shutter is opened and the preliminary exposure is performed, and the luminance information is fed back from the imaging circuit 508 to the arithmetic circuit 504. Thus, each of the control amounts is corrected, and thereafter, the main exposure is performed, and the image recording is performed by the recording circuit 510.

When performing such preliminary exposure, it is necessary to hold the shutter closed during non-exposure for the purpose of protecting the CCD. In other words, it is necessary to open the shutter only at the time of the preliminary exposure.

[Problems to be Solved by the Invention] However, when the shutter is driven by using the electromagnetic force, power is supplied to one of the shutter blades to open the shutter until the preliminary exposure is completed. Had to keep state. As a result, it is not preferable from the viewpoint of suppressing excess power consumption.

Such a problem is the same when a movie using an electronic camera with a shutter is supported or when a long-time exposure is performed by a silver halide camera. The shutter must be kept open, and power consumption is further increased. turn into.

Accordingly, an object of the present invention is to provide a camera that can mechanically lock one shutter blade for a desired time in order to realize a shutter open state required at the time of preliminary exposure, movie correspondence, or long time exposure. Is to provide.

[Means for Solving the Problems] A camera according to the present invention includes a first shutter interposed in the optical path of an optical image and urged to a first position for blocking the optical path; A first shutter driving means for driving the optical path to a second position to open the optical path, a second shutter biased to a third position to open the optical path, and a fourth position for blocking the second shutter to the optical path. A second shutter driving unit to be driven, a mirror interposed in the middle of the optical path, with the first shutter moving to the second position by the first shutter driving unit, and a mirror capable of retracting from the optical path; Shutter holding means for mechanically holding the first shutter at the second position in conjunction with the retracting operation of the mirror outside the optical path; and moving the first shutter from the second position to the first position. The shutter holding means when returning to And electromagnetic release means for releasing the holding state of the first shutter by driving the first shutter to the second position while the second shutter is at the third position. Means for holding the first shutter at the second position to stop the operation of the first shutter driving means, and following the first exposure mode, the second shutter After the first shutter has been driven to the fourth position and the first shutter has been driven to the second position, the holding state of the first shutter by the shutter holding means is released by the electromagnetic release means, and then the second shutter is released. Returning to the third position, opening the optical path, stopping the operation of the first shutter driving means after a predetermined time, returning the first shutter to the first position, the second exposure mode, and the first and second exposure modes. And releasing the holding state of the first shutter by the shutter holding means by the electromagnetic releasing means while driving the second shutter to the second and fourth positions, respectively, and then releasing the second shutter to the third position. Position, opening the optical path, stopping the operation of the first shutter driving means after a predetermined time, and returning the first shutter to the first position. It has a form.

[Action]

In the first exposure mode in which the shutter is held open at the time of preliminary exposure, movie support, or long exposure,
With the second shutter at the third position, the first shutter is driven to the second position by the operation of the first shutter driving means. Accordingly, the shutter holding means holds the first shutter at the second position to keep the light path open and stops the operation of the first shutter driving means in conjunction with the retreat operation of the mirror to the outside of the optical path. Thereby, power consumption in the shutter open state is suppressed.

In the case of the second exposure mode in which the main exposure is performed after the preliminary exposure, first, the first shutter is driven to the second position by the operation of the first shutter driving means while the second shutter is at the third position. Is done. Along with this, in conjunction with the retracting operation of the mirror outside the optical path, the shutter holding means holds the first shutter at the second position to keep the optical path open, and stops the operation of the first shutter driving means. After performing the preliminary exposure, the second shutter is driven to the fourth position, the holding state of the first shutter by the shutter holding means is released by the electromagnetic release means, and the first shutter is driven by the first shutter driving means. After holding at the second position, the second shutter is returned to the third position to open the optical path, and after a predetermined time, the operation of the first shutter driving means is stopped, and the first shutter is returned to the first position to perform the main exposure. Finish.

Further, in the case of the third exposure mode, the first and second shutters are driven to the second and fourth positions, respectively.
In this state, the shutter holding means holds the first shutter at the second position in conjunction with the retracting operation of the mirror to the outside of the optical path. Release the holding state by the holding means. Thereafter, the second shutter is returned to the third position to open the optical path, and after a predetermined time, the operation of the first shutter driving means is stopped, the first shutter is returned to the first position, and the optical path is closed.

EXAMPLES Hereinafter, the present invention will be described based on examples.

FIGS. 1 and 2 are configuration diagrams showing an embodiment of an electronic camera with a focal plane shutter to which the present invention is applied. Here, FIG. 1 is a view showing an initial state (shutter: closed) before exposure, and FIG. 2 is a view showing a shutter open state at the time of preliminary exposure.

1 and 2, reference numerals 1 and 2 denote a rear blade and a front blade, respectively, as a first shutter and a second shutter of the present invention.
Each is biased clockwise by 60. The shutter blades 1 and 2 are rotated counterclockwise by an electromagnetic force generator (not shown) as the first shutter driving means and the second shutter driving means of the present invention, and charge the springs 50 and 60.

Reference numeral 8 denotes a rotatable return lever for retracting the reflection mirror 11 from the finder optical path, and reference numeral 9 denotes a stop-down lever for controlling a stop-down mechanism (not shown).

Reference numeral 3 denotes a locking lever for locking the shutter rear blade 1 to open the aperture 14.
, An engaging pin 12 of the shutter rear blade 1 described later, an unlocking lever 4, an urging lever 5, and the like constitute a shutter holding means of the present invention. The lock release lever 4 is for releasing the engagement between the lock lever 3 and the engagement pin 12 of the rear shutter blade 1, and the urging lever 5 is locked with the rightward rotation of the lever 6. This is for turning the lever 3 counterclockwise.

15 rotates the lock release lever 4 counterclockwise (counterclockwise)
An electromagnet as an electromagnetic canceling means of the present invention for causing the electromagnetic force to be released.

 Next, the operation of this embodiment will be described.

In FIG. 1, the rear blade 1 and the front blade 2 are kept open with respect to the aperture 14. At this time, the engagement pin
Numeral 12 is at a position so as not to engage with the locking lever 3.

In order to perform the pre-exposure as the first exposure mode of the present invention by opening the aperture 14, first, the rear blade 1 is left-turned by an electromagnetic driving device (not shown) to charge the spring 50. Thus, the aperture 14 is opened.

Before or after this operation, the return lever 8 is rotated clockwise (clockwise) by an external force (not shown) to retract the mirror 11 fixed to the lever 16 out of the finder optical path. In accordance with the clockwise rotation of the return lever 8, the lever 7 rotates counterclockwise (counterclockwise), thereby rotating the lever 6 clockwise (clockwise). As a result, the engagement pin of the lever 5
13 is pushed upward, and as a result, the locking lever 3 and the locking release lever 4 are rotated.

Thus, as shown in FIG. 2, the notch 4A of the unlocking lever 4 engages with the tip 5A of the lever 5. Therefore, the clockwise operation of the locking lever 3 is suppressed, and the rear blade 1 is locked and held.

The energization of the rear blade 1 is stopped in this state, the engagement pin 12 abuts on the locking lever 3, and the opening of the aperture 14 is held.

Thereafter, preliminary exposure is performed, and the optimal aperture value and shutter speed are determined. Then, in order to perform the main exposure, which is the second exposure mode of the present invention, the electromagnetic drive device (not shown) of the front blade 2 is energized to rotate the front blade 2 counterclockwise. The electromagnet 15 is excited during the left rotation of the front blade 2, and the lever 4
Is rotated counterclockwise (counterclockwise). Then, lever 5
Rotates counterclockwise (counterclockwise), and thus levers 3, 4, 5, 6
Returns to the initial state shown in FIG.

At a point in time prior to the return of the lever, the electromagnetic drive of the rear blade 1 is also energized and positioned at a predetermined position against the spring 50. Then, after the front blade 2 is positioned at a predetermined position, energization of the front blade 2 and the rear blade 1 is released at predetermined intervals. Then, these two blades travel clockwise by the springs 60 and 50, respectively, and perform the main exposure on the CCD while forming a slit having a predetermined width.

FIG. 3 is a diagram for explaining another embodiment of the present invention.
In the figure, reference numeral 10 denotes a lever for rotating the lever 7 in conjunction with the stop-down lever 9. However, the return lever 8, the lever 16, and the mirror 11 are omitted in the drawing.

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 retreat operation of the mirror, but in the embodiment shown in FIG. The lever 7 is turned (counterclockwise) in the counterclockwise direction in conjunction with the movement or rotation of the lever 7.

That is, the lever 10 rotates clockwise (right line) due to the rotation of the stop-down lever 9 at the time of stopping down, and thus the lever 7 turns counterclockwise (left-handed rotation). The following operation is the same as that of the above-described embodiment, and locks and holds the rear blade 1.

As an electromagnetic drive device for the rear blade 1 and the front blade 2, for example, it is preferable that a coil is mounted on the surface of these blades so as to generate an electromagnetic force with a permanent magnet (not shown). Alternatively, these shutter blades can be driven by attaching a simple electromagnet.

FIG. 4 is an electrical block diagram for controlling the embodiment shown in FIGS. 1 and 2. In this figure, 51 is an image sensor, 214, 215, 216 are switches that are closed in response to pressing of a release switch, 201 is a control circuit, 202 is an SSG (synchronous signal generator), 203 is an image sensor drive circuit, and 204 is a signal. Processing circuit, 205 is a shutter time setting circuit, 206 is a shutter control circuit, 207 and 208 are correction circuits, 209 is a correction circuit, 210 is an aperture value determination circuit, 211 is a photometric element, 212 is an aperture control mechanism, and 213 is exciting. Circuit.

FIG. 5 is a flowchart showing a control procedure to be executed by the control circuit 201 shown in FIG.

Hereinafter, the control procedure in this embodiment will be described with reference to FIGS. 4 and 5.

First, when the first switch 214 is closed by pressing the relays button in the first stage (step S1 in FIG. 5), the control circuit 201
Activates the image sensor driving circuit 203 and the aperture value determination circuit 210 (step S2 in FIG. 5). As a result, the image sensor 5 is synchronized with the timing signal from the SSG (synchronous signal generator) 202.
1 is started, while the aperture value determination circuit 210 receives the object brightness information Bv from the photometric element 211 and the shutter time setting circuit 205
Aperture value Av is determined on the basis of shutter time information Tv from, and is output to aperture control mechanism 212. Then, the aperture control mechanism 212 presets the determined aperture value Av for the aperture position.

Then, the control circuit 201, the stop and wait for a certain time t ₁ required for preset operation (Fig. 5 step S3), and thereafter, the second to be turned on in the second stage depression of the release button
Check whether switch 215 is closed (fifth
Figure Step S4). As a result, if the switch 215 is closed, the control circuit 201 causes the aperture value determination circuit 210 to store the aperture value Av at that time (step S in FIG. 5).
Five). After that, the mirror is retracted and the aperture is narrowed down.

Then, the control circuit 201 instructs the trailing blade electromagnet excitation circuit 207 performs energization over a period of time t ₂ the electromagnet 217 (Fig. 5 step S6), and stops the subsequent energization (Fig. 5 step S7). The conduction period t ₂ is the time sufficient to rear blade 1 is locked by the locking mechanism and left-handed. Thus, the aperture 14 is opened and the control circuit 201
Operates the correction circuit 209 at this time (step S8 in FIG. 5).

In this state, the aperture has been narrowed down to the aperture value Av previously determined by the aperture value determination circuit 210,
The correction circuit 209 determines an appropriate shutter time based on the level of the luminance signal Y from the signal processing circuit 204 in the actual aperture state, and outputs this to the shutter time setting circuit 205 as a correction signal. As a result, the shutter time setting circuit 205
Replaces the initially set shutter time (by manual operation or the like) with the shutter time from the correction circuit 209.

After the control circuit 201 of the step S8, in such operation waits enough certain period t ₃ (FIG. 5 step S9), and the correction circuit
The output at that time is stored in 209 (step S1 in FIG. 5).
0). Next, the energization circuits 207 and 208 are instructed to energize the electromagnets 217 and 218 (step S11 in FIG. 5). As a result, the leading blade 2 turns left and the aperture 14 is closed. During this time, the control circuit 201 commands the excitation circuit 213 to excite the electromagnet 15 for a very short time (steps S12A and S12 in FIG. 5).
B), turn the lock release lever 4 counterclockwise (unlock). Therefore, the two blades 1 and 2 are
This state is maintained by the action of the electromagnets 217 and 218 while resisting the above.

Next, the control circuit 201 triggers the shutter control circuit 206 (FIG. 5, step S13). Accordingly, the shutter control circuit 206 stops the energization of the electromagnet 218 by the excitation circuit 208 in response to the vertical synchronization signal (Vd) from the SSG 202 immediately after the trigger. Thus, the leading blade 2 runs. Thereafter, the previously corrected shutter time obtained from the shutter time setting circuit 205 is counted, and at the time when the shutter time has elapsed, the excitation circuit 207 stops energizing the electromagnet 217. As a result, the rear blade 1 runs.

The proper exposure of the image sensor 51 is performed in this manner, and the image information formed by this exposure is read out in synchronization with the next vertical synchronization signal Vd, and processed by the signal processing circuit 204. Then, it is recorded on a magnetic disk or the like as a so-called one-field television signal.

Thereafter, when the first switch 214 is turned off (Step S14 in FIG. 5), the control circuit 201 stops the operation of the circuits 202, 209 and 210 (Step S15 in FIG. 5), and ends the control operation.

FIG. 6 is a flowchart showing a control procedure when using the electronic camera in the movie mode as the first exposure mode of the present invention.

First, when the mode switch 216 is turned off (opened) and the movie mode is set, the control circuit 201 switches the switch 214
Then, the image sensor driving circuit 203 and the aperture value determination circuit 210 are operated in response to turning on (closing) (step S22). At the same time, a signal of Tv = 1/60 (second) is output from the shutter time setting circuit 205 (step S23).

Next, in response to the switch 215 being turned on (step S2
4), the control circuit 201 exemplifies the electromagnet 217 (step S2
Five). Thus, the rear blade 1 is driven to open the aperture 14. When the rear blade 1 is driven and engaged with the locking lever 3, the rear blade 1 is locked (locked), so that the power supply to the electromagnet 217 is stopped (step S26).

Then, if the switch 215 is turned off (step S
27), the electromagnet 15 is excited for a very short time (step S28,
S29), whereby the rear blade 1 is unlocked. Therefore, both shutter blades 1 and 2 return to the initial state (see FIG. 1).

Thereafter, when the switch 214 is turned off (step S
30), the operations of the image sensor driving circuit 203 and the aperture value determining circuit 210 are stopped.

Although the embodiments described above apply the present invention to an electronic camera, the present invention can also be applied to a single-lens reflex camera using a normal film. However, a normal silver halide camera does not require a pre-exposure operation as in an electronic camera. Can be performed. In particular,
The electromagnet 15 is energized while the blades 1 and 2 are driven, respectively.
After releasing the lock of the rear blade 1, the front blade 2 is returned to the original position to open the optical path, and after a predetermined time, the operation of the rear blade 1tta driving means is stopped to return the rear blade 1 to the original position. Close the light path. When performing long-time exposure as the first exposure mode according to the present invention, the same operation as in the movie mode of the electronic camera may be performed.

According to the camera of the present invention, when the first shutter is driven to the second position where the optical path is opened by the first shutter driving means, the first shutter is interlocked with the retracting operation of the mirror outside the optical path. A shutter holding member that can be locked to the shutter and hold the shutter at the second position and an electromagnetic releasing unit that can release the engagement state of the first shutter with the shutter holding member are provided. At the time of exposure and movie support, or when the shutter of a normal silver halide camera is opened, it is not necessary to continue energizing the electromagnet or the like with the first shutter held at the second position. It does not require special driving means for the shutter holding means and does not require the timing of the mirror retracting operation and the shutter controlling operation which are important in the photographing sequence of the camera. It can be surely matched.

[Brief description of the drawings]

1 and 2 are configuration diagrams showing one embodiment of an electronic camera with a focal plane shutter to which the present invention is applied, FIG. 3 is a configuration diagram showing another embodiment of the present invention, and FIG. 4 is FIG. And FIG. 6 is an electrical block diagram for controlling the present embodiment shown in FIG. 2. FIGS. 5 and 6 are flowcharts showing control procedures to be executed by the control circuit 201 shown in FIG. FIG. 3 is a block diagram illustrating general preliminary exposure. 1 ... rear blade, 2 ... front blade, 3 ... locking lever, 4 ... locking release lever, 5 ... urging lever, 8 ... return lever, 9 ... aperture stop lever, 11 ... reflection Mirror, 15 electromagnet, 80 spring for returning mirror.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Nobuaki Date 770 Shimonoge, Takatsu-ku, Kawasaki Canon Inc. Tamagawa Works (72) Inventor Shuichiro Saito 770 Shimonoge Shimoge, Takatsu-ku Kawasaki Canon Inc. Tamagawa Works (72) Inventor Yukio Ogawa 770 Shimonoge, Takatsu-ku, Kawasaki City Inside the Tamagawa Works of Canon Inc. (56) References JP-A-62-128675 (JP, A) JP-A-58-130329 (JP, A)

Claims (1)

(57) [Claims] 1. A first shutter interposed in the optical path of an optical image and urged to a first position for blocking the optical path, and driving the first shutter to a second position for opening the optical path. A first shutter driving unit; a second shutter biased to a third position for opening the optical path; a second shutter driving unit for driving the second shutter to a fourth position for blocking the optical path; A mirror that can be retracted from the optical path along with the movement of the first shutter to the second position by the first shutter driving means, and a retracting operation of the mirror out of the optical path. Shutter holding means for mechanically holding the first shutter at the second position in conjunction with the first shutter; and returning the first shutter from the second position to the first position by the shutter holding means. The holding state of one shutter Electromagnetic release means for removing the first shutter from the first position to the second position in a state where the second shutter is at the third position. A first exposure mode in which the operation of the first shutter driving unit is stopped while being held at the two positions, and the second shutter is driven to the fourth position following the first exposure mode, and the first exposure mode is set. After the holding state of the first shutter by the shutter holding means is released by the electromagnetic release means while the shutter is driven to the second position, the second shutter is returned to the third position to open the optical path. A second exposure mode in which the operation of the first shutter driving means is stopped after a predetermined time and the first shutter is returned to the first position, and the first and second shutters are moved to the second and second exposure modes. After the holding state of the first shutter by the shutter holding means is released by the electromagnetic release means in a state where the shutters are driven to the respective positions, the second shutter is returned to the third position to open the optical path, and after a predetermined time, A camera having at least the first exposure mode among the third exposure modes for returning the first shutter to the first position by stopping the operation of the first shutter driving unit.