JPH07159852A - Exposure controller - Google Patents

Abstract

PURPOSE:To provide an inexpensive exposure controller capable of respectively and independently controlling exposure time and the size of an aperture. CONSTITUTION:This controller is provided with shutter blades 2a and 2b capable of changing the size of the aperture transmitting an exposing luminous flux in accordance with moving amount in the case of opening and closing, a solenoid plunger 13 provided with a movable iron core 13a driving the shutter blades 2a and 2b, a lever 9 controlling the moving of the movable iron core 13a of the solenoid plunger 13, a tension spring 10 pressing the lever 9 in the direction where the moving of the movable iron core 13a is controlled, and a controlling circuit 14 setting a voltage driving the solenoid plunger 13; when a low voltage is set by the controlling circuit 14, the moving of the movable iron core 13a is controlled by the lever 9, and when a high voltage is set, the movable iron core 13a releases control by means of the lever 9 against the pressing force of the tension spring 10 and is moved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exposure control device, and more particularly, to an exposure control device for controlling the size of an opening through which an exposure light beam passes and the time during which the exposure light beam is opened.

[0002]

2. Description of the Related Art Conventionally, various types of exposure control devices for cameras have been proposed. They are provided inside a camera on a photographing optical path from a subject, for example, and have a size of an aperture for passing an exposure light beam and an aperture. By controlling the time and
It controls the exposure.

As such an exposure control device, for example, Japanese Patent Application Laid-Open No. 5-45698 discloses a device which controls an exposure time and an aperture diameter independently by using one set of sectors and one stepping motor. ing.

In Japanese Patent Laid-Open No. 4-194912, a shutter blade movable between an open position and a closed position, an opening spring for urging the shutter blade in the opening direction, and the shutter blade at the closed position. A closing member that is displaceable between a holding position for holding and a permissible position for allowing displacement in the opening direction; and an electromagnetic drive source including a solenoid plunger that drives the closing member from the restricting position to the permissible position by being energized An exposure control device for urging the closing member to a regulation position and including a closing spring having a force amount characteristic that is substantially similar to the characteristic of the attraction force amount of the electromagnetic drive source is described.

In addition, two solenoid plungers are provided, one of them is used to change the opening diameter of the sector, and the other one is used to control the time for opening the sector. Exposure control devices have been proposed.

[0006]

However, in the one disclosed in Japanese Patent Laid-Open No. 5-45698, since the stepping motor is used, the cost is high including the control circuit system.

Further, in the above-mentioned Japanese Patent Laid-Open No. 4-194912, the size of the aperture through which the exposure light flux passes and the time during which the aperture is open cannot be controlled independently of each other.

Further, in the case of using the above two solenoid plungers, the cost is higher than that in the case of using one solenoid plunger, and the apparatus becomes large in size.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an inexpensive exposure control device capable of independently controlling the exposure time and the size of the opening.

[0010]

In order to achieve the above object, the exposure control apparatus according to the present invention can change the size of the opening through which the exposure light flux passes in accordance with the amount of movement when opening and closing. A shutter blade, an electromagnetic drive source having a movable part for driving the shutter blade, a regulation means for regulating the movement of the movable portion of the electromagnetic drive source, and a regulation means for regulating the movement of the movable portion. An urging means for urging and a control means for setting a voltage for driving the electromagnetic drive source are provided, and when the control means sets a low voltage, movement of the movable portion is restricted by the restriction means. When the high voltage is set, the movable portion moves against the biasing force of the biasing means by releasing the regulation by the regulating means.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 7 show a first embodiment of the present invention, and FIG. 1 is a front view showing a configuration of an exposure control device of the first embodiment.

This exposure control device allows the exposure light flux to pass by blocking all or part of a circular hole 1 formed in a shutter base plate (not shown) with two shutter blades 2a and 2b which cooperate with each other. It defines the opening.

The shutter blades 2a, 2b are thin plate members having various curved contours for forming the opening, and their ends are respectively rotated on shafts 3a, 3b fixedly planted on the shutter base plate. The long holes 4a and 4b for opening and closing the shutter blades are provided while being supported as much as possible.

The long holes 4a of the shutter blades 2a, 2b,
4b are overlapped with each other to form a common hole, into which a drive pin 6a fixed from one end of the sector lever 6 in the optical axis direction is fitted.

The sector lever 6 is rotatably supported by a shaft 7 fixed to the shutter base plate at a substantially central portion thereof, and a pin 6b is fixedly planted at the other end opposite to the drive pin 6a. ing.

The pin 6b is adapted to engage with a movable iron core 13a which is a movable portion of a solenoid plunger 13 which is an electromagnetic drive source. This solenoid plunger 13
Is a U-shaped yoke 13 fixed to the shutter base plate.
c, a solenoid coil supported by the yoke 13c, and a movable iron core 13a fitted in the solenoid coil so as to be able to move in and out.

The movable iron core 13a has a flange portion 13b projecting in the middle of the portion projecting from the solenoid plunger 13, and a cam portion 13f on the end side thereof.
Is provided with a flange portion 13e and a flange portion 13d at the end portion with a slight interval.

The flange portion 13b and the yoke 13c
A closing spring 5 is fitted between and between and so as to surround the movable iron core 13a. As a result, the movable iron core 13a is moved downward in FIG.
It is always urged toward the stopper 8) and is stable at the position where its tip end contacts the stopper 8. That is, when the solenoid plunger 13 is not energized, the shutter blades 2a and 2b are urged in the closing direction and are stable at the position as shown in FIG.

The pin 6b of the sector lever 6 is fitted between the flange portion 13d and the flange portion 13e, and in conjunction with the movement of the movable iron core 13a,
When the sector lever 6 rotates and the movable iron core 13a moves by the maximum stroke, the state shown in FIG. 3 is reached and the shutter blades 2a and 2b are fully opened.

A lever 9 as a restricting means is provided in the vicinity of the movable iron core 13a, is rotatably supported by a shaft 12 fixedly planted on the shutter base plate, and a tension spring 10 as an urging means is installed. As a result, it is urged counterclockwise in FIG.

Due to the biasing force of the tension spring 10, the stopper contact portion 9a at one end of the lever 9 is stable at the position where it abuts on the stopper 11 fixed to the shutter base plate in the initial state shown in FIG. . At this time, the locking portion 9b at the other end of the lever 9 is not in contact with the movable iron core 13a, and the movement of the movable iron core 13a is not locked.

When the solenoid plunger 13 is energized and the movable iron core 13a moves upward in FIG. 1 to the state shown in FIG. 2, the engaging portion 9b at the tip of the lever 9 moves the movable iron core 13a.
The movable iron core 13a is prevented from moving further upward in FIG.

The movable iron core 13 resists the locking of the lever 9.
When “a” further moves upward in FIG. 2, the cam portion 13f of the movable iron core 13a rotates the lever 9 in the clockwise direction in FIG. 2 while charging the tension spring 10.

Further, a PI (photo interrupter) 15 fixed to the shutter base plate is provided on the passage of the tip of the shutter blade 2a so as to detect the moving state of the shutter blade 2a. ing. This PI
Reference numeral 15 indicates that the output state changes during the transition from the state shown in FIG. 1 to the state shown in FIG. 2 just before the opening by the shutter blades 2a and 2b begins to open. It is adapted to be taken into the control circuit 14 as a control means.

The control circuit 14 receives the photometric information about the subject, the ISO information about the film sensitivity, etc., and enters various photographing conditions (for example, whether the lens is wide-angle or telephoto, or whether the camera mode is shutter priority or aperture priority). Etc.) and controls the voltage applied to the solenoid plunger 13 and the time.

In the present embodiment, the aperture value (aperture value) of the aperture through which the exposure light flux passes is divided into two stages, full aperture as shown in FIG. 3 and intermediate aperture as shown in FIG. It is designed to be controlled.

Next, the operation of the first embodiment will be described.
When a release button (not shown) is pressed, photometric information and I
The control circuit 14 sets the aperture value and the second based on the SO information and the like.

First, when the aperture value is set to the medium aperture, the control circuit 14 sets the drive voltage of the solenoid plunger 13 to a low voltage and starts energization. Then, the movable iron core 13a is moved by the electromagnetic force to the solenoid plunger 13a.
It is attracted inside and starts moving upward in FIG. 1 while charging the closing spring 5.

As a result, the pin 6b of the sector lever 6 fitted to the movable iron core 13a moves upward in FIG. 1, and the sector lever 6 rotates about the shaft 7 in the counterclockwise direction in FIG. .

When the drive pin 6a at the other end of the sector lever 6 moves downward in FIG. 1, the shutter blades 2a and 2b rotate about the shafts 3a and 3b, respectively, in directions away from each other, and the shutter blades 2a and 2b move in the circular hole 1. The opening starts from the center.

Immediately before this, the tip of the shutter blade 2a withdraws from the photoelectric detector of PI15, and P is detected.
I15 changes its output signal, and the changed output signal is input to the control circuit 14. At this point, the control circuit 14 starts measuring the control time for exposure control (see FIG. 4).

When the movable iron core 13a continues to move in the direction in which the movable iron core 13a is further retracted into the solenoid plunger 13, the shutter blades 2a and 2b gradually form a large opening.

When the movable iron core 13a moves to the position shown in FIG. 2, the locking portion 9b of the lever 9 contacts the cam portion 13f of the movable iron core 13a. Since the lever 9 is biased counterclockwise in FIG. 2 by the tension spring 10 as described above, the movable iron core 13a is prevented from moving further upward.

At this time, the amount of force that prevents the movable iron core 13a from moving by the lever 9 biased by the tension spring 10 is lower than that of the solenoid plunger 1 to which a low voltage is applied.
Since it is set to be larger than the force amount for driving the movable iron core 13a by 3, the movement of the movable iron core 13a is stopped in the state shown in FIG. There is.

The control circuit 14 cuts off the power supply to the solenoid plunger 13 when the control time, which starts counting from the time of opening, reaches the preset proper exposure time.

Then, the movable iron core 13a moves downward in FIG. 2 by the urging force of the closing spring 5, and the shutter blades 2a, 2
When b is opened, it starts to close. Then, at the position where the opening is completely closed, the shutter blade 2a enters the photoelectric detecting portion of the PI 15, and the signal output from the PI 15 changes as shown in FIG. And the movable iron core 13a is the stopper 8
Stablely stops at the position where it comes into contact with, and returns to the state shown in FIG. 1, and the photographing operation ends.

Next, when the aperture value is set to full open, the control circuit 14 sets the drive voltage of the solenoid plunger 13 to a high voltage and starts energization. And FIG.
Until the state shown in (1), the same operation as in the case where the above-mentioned middle aperture is set is performed.

In the state shown in FIG. 2, this time, the amount of force for driving the movable iron core 13a by the solenoid plunger 13 to which a high voltage is applied is larger than that of the lever 9 urged by the tension spring 10. The movable iron core 13a continues to move upward in FIG. 2 against the locking force of the lever 9, because the movable iron core 13a is set to have a force larger than the force that prevents the movement of the core 13a. The lever 9 is actuated against the urging force of the tension spring 10 by the cam portion 13f, as shown in FIG.
It is rotated in the clockwise direction and moved until the state shown in FIG. 3 is reached.

At this time, since the movable iron core 13a is in the position moved by the maximum stroke, the movable iron core 13a stops in this state, and the opening diameter is kept in the fully opened state. The control circuit 14 cuts off the energization to the solenoid plunger 13 when the control time being counted reaches the time at which the preset proper exposure is reached (see FIG. 5).

Then, the movable iron core 13a moves downward in FIG. 3 by the urging force of the closing spring 5, and the shutter blades 2a, 2
b begins to close. The movable iron core 13a moves downward, and the cam portion 13f causes the lever 9 to rotate counterclockwise in FIG.

When the lever 9 passes through the cam portion 13f, it stops with the stopper abutting portion 9a abutting the stopper 11, and the lever 9 and the movable iron core 13a maintain a separated state.

When the movable iron core 13a is further moved, the shutter blades 2a and 2b are closed, and the shutter blade 2a enters the photoelectric detecting portion of the PI15 at the position where the opening is closed, and the signal output from the PI15 is shown in FIG. It changes as shown in. Then, when the movable iron core 13a moves until it comes into contact with the stopper 8, it returns to the initial state shown in FIG.

6 and 7 are control time charts in the case where the proper exposure is performed before reaching the middle aperture and the full aperture aperture, respectively. In this case, if the solenoid plunger 13 is de-energized at the time when the control exposure for proper exposure is reached, the shutter blades 2a, 2b are opened,
The urging force of the closing spring 5 changes the movement in the closing direction. The other parts are almost the same as described above.

As described above, according to the first embodiment, one inexpensive solenoid plunger is used without using an expensive stepping motor.
By driving a pair of shutter blades, the aperture diameter and exposure time can be controlled independently.

8 to 10 show a second embodiment of the present invention. In the second embodiment, the portions of the movable iron core and the sector lever of the first embodiment described above are slightly changed, and therefore only this point will be mainly described, and the same reference numerals are given to other similar portions. Will be omitted and the description will be omitted.

The sector lever 6 is provided with an open spring 21 for urging the sector lever 6 in the counterclockwise direction in FIG. 8 (that is, the direction in which the shutter blades 2a and 2b are opened).

Further, the movable iron core 13a has the flange portion 13e provided with the cam portion 13f, but the flange portion 1
3d is not provided, and the end surface of the flange portion 13e is the end surface 13g of the movable iron core 13a. Needless to say, the position of the stopper 8 is appropriately changed according to the change in the length of the movable iron core 13a.

In the state as shown in FIG. 8 before the solenoid plunger 13 is energized, the pin 6b of the sector lever 6 pushes the end surface 13g of the movable iron core 13a by the open spring 21 to move the movable iron core 13a. Although it tries to move upward in FIG. 8, due to the biasing force of the opening spring 21, the closing spring 5
The force for pushing the movable iron core 13a downward in FIG. 8 is set to be stronger, so that the movable iron core 13a is stable at the position where it abuts on the stopper 8. Other parts are almost the same as those in the above-mentioned first embodiment.

Next, the operation of the second embodiment will be described.
First, when the solenoid plunger 13 is driven with a low voltage, the movable iron core 13a starts moving upward in FIG. 8 as in the first embodiment. Then, the sector lever 6 starts to rotate counterclockwise by the urging force of the opening spring 21 because the end face 13g of the movable iron core 13a, which has stopped its rotation, is no longer supported.

At this time, with respect to the moving speed of the movable iron core 13a, the pin 6b of the sector lever 6 by the opening spring 21 is moved.
Since the moving speed of the sector lever 6 is set to be slower, the counterclockwise rotation speed of the sector lever 6 is determined by the opening spring 21 and is not related to the moving speed of the movable iron core 13a.

When the sector lever 6 is rotated by the opening spring 21, the shutter blades 2a and 2b are opened and stopped when the pin 6b of the sector lever 6 comes into contact with the end surface 13g of the movable iron core 13a, and the opening diameter 1 Keeps the state of medium aperture. Of course, at this time, since the movable iron core 13a is driven at a low voltage, it cannot withstand the locking portion 9b of the lever 9 and is locked, and is stopped in the state shown in FIG.

Similar to the first embodiment, the control circuit 14 sets the aperture value and the opening time for proper exposure based on the photometric information, ISO information, etc., and when this control time elapses. , Turn off the power supply to the solenoid plunger 13.

Then, the movable iron core 13a moves downward in FIG. 9 by the closing spring 5, and while the opening spring 21 is charged, the sector lever 6 is rotated clockwise to close the shutter blades 2a and 2b and move. The iron core 13a stops at the position where it abuts on the stopper 8 and returns to the initial state shown in FIG.

Next, the solenoid plunger 13 is applied at a high voltage.
When is driven, the movable iron core 13a moves to the state shown in FIG. 10 against the locking force of the lever 9 biased by the tension spring 10, as in the first embodiment. Movable iron core 1
The maximum stroke movement of 3a drives the sector lever 6 to a position where the shutter blades 2a and 2b are fully opened. Other functions are almost the same as those in the first embodiment described above.

According to the second embodiment, the same effect as that of the above-described first embodiment is obtained, and the voltage applied to the solenoid plunger 13 is changed to change the movable iron core 1
Even if the moving speed of 3a changes, the rotation speed when the sector lever 6 opens is not changed because it is determined by the opening spring 21, so the opening speed of the shutter blades 2a, 2b changes even if the aperture diameter is changed. The exposure can be controlled without doing this.

[0056]

As described above, according to the present invention, an inexpensive exposure control device capable of independently controlling the exposure time and the size of the opening is provided.

[Brief description of drawings]

FIG. 1 is a front view showing an exposure control device according to a first embodiment of the present invention, including a partial block diagram.

FIG. 2 is a front view showing the exposure control device when the aperture is in the state of a middle diaphragm in the first embodiment.

FIG. 3 is a front view showing the exposure control device when the opening is fully opened in the first embodiment.

FIG. 4 is a time chart showing a state when the solenoid plunger is driven at a low voltage in the exposure control device of the first embodiment.

FIG. 5 is a time chart showing a state when the solenoid plunger is driven at a high voltage in the exposure control device of the first embodiment.

FIG. 6 is a time chart showing a state where the control time is short when the solenoid plunger is driven at a low voltage in the exposure control device of the first embodiment.

FIG. 7 is a time chart showing a state where the control time is short when the solenoid plunger is driven at a high voltage in the exposure control device of the first embodiment.

FIG. 8 is a front view including a partial block diagram showing an exposure control device according to a second embodiment of the present invention.

FIG. 9 is a front view showing the exposure control device when the aperture is in the state of a middle diaphragm in the second embodiment.

FIG. 10 is a front view showing the exposure control device when the opening is fully opened in the second embodiment.

[Explanation of symbols]

 2a, 2b ... Shutter blade 9 ... Lever (regulating means) 10 ... Tension spring (biasing means) 13 ... Solenoid plunger (electromagnetic drive source) 13a ... Movable iron core (movable part) 14 ... Control circuit (control means)

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] January 13, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0018

[Correction method] Change

[Correction content]

The flange portion 13b and the yoke 13c
A closing spring 5 is fitted between and between and so as to surround the movable iron core 13a. As a result, the movable iron core 13a is moved downward in FIG.
It is always urged toward the stopper 8) and is stable at the position where its tip end contacts the stopper 8. That is, when the solenoid plunger 13 is not energized, the shutter blades 2a, have 2b is closed, is stable at a position shown in FIG.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0036

[Correction method] Change

[Correction content]

Then, the movable iron core 13a moves downward in FIG. 2 by the urging force of the closing spring 5, and the shutter blades 2a, 2
b starts to close contrary to when it opens. Immediately after the opening is closed, the shutter blade 2a enters the photoelectric detector of the PI 15, and the signal output from the PI 15 changes as shown in FIG. Then, the movable iron core 13a stably stops at the position where it abuts on the stopper 8, returns to the state shown in FIG. 1, and the photographing operation ends.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0042

[Correction method] Change

[Correction content]

When the movable iron core 13a is further moved, the shutter blades 2a and 2b are closed and the opening is completed.
At the position immediately after that , the shutter blade 2a enters the photoelectric detector of the PI 15, and the signal output from the PI 15 changes as shown in FIG. And the movable iron core 13a is the stopper 8
When it moves until it comes into contact with, it returns to the initial state shown in FIG.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0043

[Correction method] Change

[Correction content]

6 and 7 are control time charts in the case where the proper exposure is performed before reaching the middle aperture and the full aperture aperture, respectively. In this case, if the solenoid plunger 13 is de-energized at the time when the control exposure for proper exposure is reached, the shutter blades 2a, 2b are opened,
Turn to move in the closing direction by the urging force of the 5 I be closed. The other parts are almost the same as described above.

Claims (1)

[Claims] 1. A shutter blade capable of changing the size of an opening for passing an exposure light beam according to a movement amount when opening and closing, an electromagnetic drive source having a movable portion for driving the shutter blade, Regulating means for regulating the movement of the movable portion of the drive source, biasing means for biasing the regulating means in the direction of regulating the movement of the movable portion, and control means for setting a voltage for driving the electromagnetic driving source. , The movement of the movable part is restricted by the restricting means when the voltage is set to a low voltage by the control means, and the movable part resists the urging force of the urging means when the voltage is set to a high voltage. Then, the exposure control device is characterized in that the restriction by the restriction means is released to move.