JP3276988B2 - Camera lens shutter device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens shutter device for a camera.

[0002]

2. Description of the Related Art In recent years, camera shutters using actuators to drive shutter blades have been widely used because they can accurately control a shutter speed to an appropriate value in a program shutter or the like.

For example, Japanese Patent Application Laid-Open No. 60-57327 discloses that an output shaft of a motor such as a stepping motor and a blade opening / closing member are gear-connected to each other by using only an actuator as a drive source of a shutter blade, and the motor is rotated forward. The document describes that the shutter blade which is also used as an aperture blade is opened by the operation, and the shutter blade is closed by the reverse rotation operation of the motor.

[0004] Japanese Patent Application Laid-Open No. 1-92731 discloses that
Assuming that a spring is used as a drive source for opening the shutter blades, the blade opening / closing lever is operated in the shutter blade opening direction by the biasing force of the spring in the first stage of traveling of the driving member gear-connected to the actuator, and then the driving member In the second stage of the traveling, the blade opening / closing lever is driven in the shutter blade closing direction against the urging force of the spring, so that the opening characteristic of the shutter blade depends on the spring.

Japanese Utility Model Publication No. Sho 63-20981 discloses a technique for locking and releasing a front blade and a rear blade using first and second electromagnet devices.

[0006]

However, in a camera shutter using only an actuator as a driving source of the shutter blade, when the operating direction of the shutter blade changes from the opening direction to the closing direction, the change in the driving direction of the actuator is performed by an electric motor. In spite of the fact that it is performed instantaneously, the inertia of the shutter blades and associated components causes a mechanical delay, and the acceleration and deceleration time before and after the mechanical delay causes an increase in the shutter speed. Was extremely difficult.

In a camera shutter using a spring as a drive source for opening the shutter blades, the actuator drives the blade opening / closing lever in the closing direction against the urging force of the spring. Although a large-torque motor is required, a small-sized motor with a small driving force has to be used due to space needs due to the downsizing and large-diameter of the camera itself. Therefore, it is extremely difficult to increase the shutter speed. there were.

In a camera shutter for locking and releasing the front blade and the rear blade using the first and second electromagnet devices, the front blade and the rear blade are driven by the biasing force of the spring. The traveling speed cannot be changed, and therefore, the leading blade traveling at a constant speed releases the locking of the rear blade by pressing the locking lever at one of two positions during the traveling of the leading blade. Therefore, only two types of shutter speeds can be set, so that it is difficult to finely control the exposure time, and the structure tends to be complicated.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has a relatively simple structure, can control a shutter speed finely and accurately, and uses an actuator having a small driving force. Another object of the present invention is to provide a camera lens shutter device capable of increasing the shutter speed.

[0010]

SUMMARY OF THE INVENTION A camera lens shutter according to the present invention performs an opening operation of opening a shutter opening by a biasing force of a spring at the time of release, and a closing operation of a shutter opening by a biasing force of a spring at the time of release. It is reciprocated by a closing blade and one stepping motor , and operates in one direction at the time of release so as to be in front of the opening blade.
A member for starting the closing operation of the serial closed solved suppression of blades the opening the closing blade opening operation and the blade in order, the stearate
And a control circuit for controlling the rotation of the stepping motor , wherein the control circuit applies a voltage to the stepping motor.
By controlling the pulse time, the time from the start of the opening operation of the opening blade to the start of the closing operation of the closing blade is electrically controlled.

[0011]

[0012]

[0013]

In the camera lens shutter device of the present invention, the time from the start of the operation of the open blade to the start of the operation of the close blade is electrically controlled, thereby controlling the shutter speed. That is, in the camera lens shutter of the present invention,
A stepping motor is used as a tutor. Soshi
Control the pulse time supplied to the stepping motor.
By changing the rotation speed, thereby opening the blade
Change the time from the start of the operation of the
Control the shutter speed.

[0014]

[0015]

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of a camera lens shutter device according to the present invention will be described below with reference to FIGS.

As shown in FIG. 1, the camera lens shutter device of this embodiment includes a drive ring 1 disposed around a shutter opening O, a stepping motor 2 (actuator) for rotating the drive ring 1, and A control circuit 3 for controlling the driving of the stepping motor 2, an opening blade 4 for performing a shutter opening stroke by the urging force of a spring (not shown) with the rotation of the driving ring 1, and a drawing with the rotation of the driving ring 1 And a closing blade 5 that performs a shutter closing stroke by the urging force of a spring that does not.

The drive ring 1 has a ring shape and is rotatably supported around a shutter opening O, and a gear 6 and a cam 7 are formed at a part of an outer edge thereof. A pinion gear 8 attached to the output shaft of the stepping motor 2 meshes with the gear unit 6. On the right side of the cam portion 7, a cam surface 7a for returning the open blade 4 and the closed blade 5 is formed. A substantially fan-shaped locking piece 9 is rotatably attached to the cam portion 7 via a connecting shaft 10. Since the locking piece 9 is urged clockwise by a spring (not shown) and its rotation to the right is more restricted than in the state of FIG. 1, it is normally held at the position of FIG. Only when pressed in the same direction.

The stepping motor 2 has, for example, a rotor of four magnetic poles in which S poles and N poles are alternately arranged at intervals of 90 degrees, and a stator having a pair of magnetic poles is arranged on both sides of the rotor, respectively. By alternately inverting the pulse applied to each coil wound on two stators, the magnetic poles of each stator are alternately inverted, and the rotor is rotated by 45 degrees.

The control circuit 3 controls a pulse train applied to the stepping motor 2 and a pulse time of each pulse of the pulse train according to a shutter speed.

The opening blade 4 is rotatably mounted on a main plate (not shown) via a fixed shaft 11. One end of an opening / closing lever 12 is connected to a position separated from the fixed shaft 11 by a predetermined distance. ing. Open / close lever 12
Has an L-shape, is rotatably attached to a main plate (not shown) via a central shaft 13, one end of which is connected to the opening blade 4 via a connecting shaft 14, and a projection formed at the other end. 12a is locked to the arc-shaped locking surface of the locking piece 9.

The closing blade 5 is rotatably mounted on a base plate (not shown) via a fixed shaft 15. One end of an opening / closing lever 16 is connected to a position separated from the fixed shaft 15 by a predetermined distance. ing. Open / close lever 16
Has an L-shape, is rotatably attached to a base plate (not shown) via a central shaft 17, one end of which is connected to the closing blade 5 via a connecting shaft 18, and a projection formed at the other end. 16a is locked to the arc-shaped locking surface of the locking piece 9.

Next, the operation of the camera lens shutter device will be described with reference to FIGS.

In the initial state, the drive ring 1 is stopped with the pulse [L, L] applied to the stepping motor 2 shown in FIG. 1 as shown on the left end of the graph of FIG. As shown in FIG. 1, in a state where the opening blade 4 closes the shutter opening O and the closing blade 5 opens the shutter opening O, the projection 12a of the opening / closing lever 12 and the opening / closing lever 1 are opened.
6, the projection 16a is locked on the locking surface of the locking piece 9, and the shutter is closed.

From such a state, an appropriate shutter speed is determined in accordance with the exposure conditions, and the control circuit 3 responds accordingly, for example, as shown in FIG. 4 by [H, L]-[H,
A pulse train of [H]-[L, H]-[L, L]-[H, L] is set, the pulse time of each of the first to third pulses is 3 ms, and the pulse time of the fourth pulse is 4 ms. , 5
Set the pulse time of the third pulse to 3 ms.

At the time of release, as shown in FIG. 4, the control circuit 3 sends [H,
L]-[H, H]-[L, H]-[L, L]-[H,
L], the output shaft of the stepping motor 2 rotates clockwise, so that the drive ring 1 rotates counterclockwise via the pinion gear 8 and the gear portion 6, and the third [L, H] When the rotation of the drive ring 1 by the pulse is completed, the projection 12a of the opening / closing lever 12 is released from the locking surface of the locking piece 9, and the opening / closing lever 12 is turned clockwise by the urging force of a spring (not shown). Then, the opening blade 4 rotates clockwise through the connecting shaft 14, and the shutter opening O is opened. And the fifth [H, L]
When the rotation of the output shaft and the drive ring 1 due to the pulse is completed, the protrusion 16a of the opening / closing lever 16 is released from the locking surface of the locking piece 9 and the opening / closing lever 16 is biased by the spring (not shown). The closing blade 5 rotates clockwise through the connecting shaft 18 to rotate clockwise, and the shutter opening O
Is closed.

Here, the shutter speed is determined by the strength of the springs for driving the opening blade 4 and the closing blade 5 and the time difference from the start of the operation of the opening blade 4 to the start of the operation of the closing blade 5. In this camera lens shutter device, the time difference between the start of operation of each blade is the third [L, H] and the fourth [L, H] before the start of operation of the closing blade 5.
L] (pulse time). That is, here, the shutter speed is set by setting the pulse time of each of the first to third and fifth pulses to 3 ms and setting only the pulse time of the fourth pulse to 4 ms. For example, if the fourth pulse time is shortened to 2 ms or 3 ms, the shutter speed increases, and as the pulse time increases to 5 ms or 6 ms, the shutter speed decreases.

After the release is completed in this manner, as shown in FIG. 4, the [L, L]-is applied to the stepping motor 2 to which the above-mentioned [H, L] pulse is applied.
When a pulse train of [L, H]-[H, H]-[H, L]-[L, L] is supplied, the output shaft of the stepping motor 2 rotates counterclockwise counterclockwise, thereby causing the pinion gear 8 and the gear portion 6 to rotate. , The drive ring 1 rotates clockwise in the reverse direction. In this manner, the rotation of the drive ring 1 by the first [L, L] pulse causes the locking piece 9 to be pushed by the projection 16a of the opening / closing lever 16 and to rotate counterclockwise, thereby causing the second [L, L] to rotate counterclockwise. , H], the rotation of the drive ring 1 by the third [H, H] and fourth [H, L] pulses,
The projection 16a of the opening / closing lever 16 and the projection 12a of the opening / closing lever 12 are guided by the cam surface 7a of the cam portion 7, and the closing blade 5 and the opening blade 4 rotate counterclockwise.
a and 16a are locked on the locking surface of the locking piece 9 and return to the original state.

In this embodiment, the time from the start of the operation of the open blade 4 to the start of the operation of the close blade 5 is controlled by controlling the pulse time of each pulse of the pulse train supplied to the stepping motor 2. The time from the start of operation of the opening blade 4 to the start of operation of the closing blade 5 may be controlled by controlling the voltage and / or current supplied to the stepping motor 2. Various motors may be used as the actuator.

Next, a second embodiment of the present invention will be described with reference to FIGS.

As shown in FIG. 5, the camera lens shutter device of this embodiment includes an opening blade 20, 21 for performing a shutter opening stroke , an iris motor 22 for driving the opening blades 20, 21 and a shutter closing stroke . Do closed feather 2
3 and 24, an iris motor 25 for driving the closing blades 23 and 24, and a control circuit 26 for electrically controlling the iris motor 22 and the operation start time of the iris motor 25.

The iris motors 22 and 25 have S poles.
A rotor having two magnetic poles with N poles arranged at 180-degree intervals, and magnetic poles of a coil disposed on both sides of the rotor, wherein the rotor rotates by a predetermined angle in both forward and reverse directions. Things. Here, although the iris motor is used as the actuator for driving the opening blade and the actuator for driving the closing blade, another actuator such as a stepping motor may be used.

The control circuit 26 electrically controls the operation start time of the iris motor 22 and the iris motor 25. Although the control circuit 26 controls only the operation start time of the iris motors 22 and 25 here, the drive speed of the iris motors 22 and 25 may be controlled.

The opening blades 20 and 21 are rotatably mounted on a base plate 29 via fixed shafts 27 and 28, respectively, and are provided with operating pins 30 of the iris motor 22.
And are connected to each other.

The closing blades 22 and 23 are rotatably attached to the base plate 29 via fixed shafts 31 and 32, respectively, and operate pins 33 of the iris motor 25.
And are connected to each other.

Next, the operation of the camera lens shutter device will be described with reference to FIGS.

In the initial state, as shown in FIG. 5, the iris motors 22 and 25 stop at a position where the iris motors are fully rotated clockwise, and the opening blades 20 and 21 and the closing blade 23,
24 are held in a closed state, and the shutter opening O is closed.

From such a state, as shown in the graph of FIG. 9, a driving current in the + direction is applied to the ISM1 (corresponding to the iris motor 25). In this case, the iris motor 25 shown in FIG. 5 is driven to rotate counterclockwise to operate the operating pin 33 upward, and as shown in FIG.
Rotates clockwise, the closing blade 24 rotates clockwise, and the closing blades 23 and 24 stop in a fully opened state.

At the time of release, an appropriate shutter speed is determined according to the exposure conditions, and the control circuit 26
Electrically controls the operation start time of the opening blade driving actuator 22 and the closing blade driving actuator 25. That is, first, the control circuit 26 controls the ISM2 (corresponding to the iris motor 22) as shown in the graph of FIG.
6 to rotate the iris motor 22 shown in FIG. 6 counterclockwise to operate the operating pin 30 upward, and as shown in FIG.
0 is rotated clockwise and the opening blade 21 is rotated counterclockwise to open the shutter opening O. Then, after a predetermined time elapses as shown in the graph of FIG. 9, ISM1 (corresponding to the iris motor 25) 7 to rotate the iris motor 25 shown in FIG. 7 clockwise to actuate the operating pin 33 upward. As shown in FIG. 8, the closing blade 23 is turned clockwise. Move and close blade 2
4 is rotated counterclockwise to close the shutter opening O.

Here, the iris motors 22, 2
5 to maximize the voltage and current supplied to
0, 21 and the moving speed of the closing blades 23, 24 are maximized, and only the operation start time of the iris motors 22, 25 is changed to perform control.
By controlling the voltage and / or current supplied to 25 to change the rotation speed of the actuators 22, 25,
The moving speed of the opening blades 20, 21 and the closing blades 23, 24 can be changed, and these can be used alone or in combination to control the shutter speed in a wider range.

Finally, as shown in the graph of FIG.
A drive current in the negative direction is applied to M2 (corresponding to the iris motor 22). In this case, the iris motor 22 shown in FIG. 8 is driven to rotate clockwise to operate the operating pin 30 upward, and as shown in FIG. 5, the opening blade 20 rotates counterclockwise and the opening blade 21 Turns clockwise and closes blade 2
0, 21 stop in the closed state.

[0042]

According to the camera lens shutter device of the present invention, since the opening blade and the closing blade are provided, the shutter speed can be increased even when, for example, an actuator having a small driving force is used. Moreover, since the shutter speed is controlled by electrically controlling the time from the start of the operation of the opening blade to the start of the operation of the closing blade, the structure is relatively simple, and the shutter speed is finely and accurately controlled. Can be.

[Brief description of the drawings]

FIG. 1 is a plan view showing a state before release of a camera lens shutter device according to a first embodiment of the present invention.

FIG. 2 is a plan view showing a state after the opening blades of the camera lens shutter device according to the first embodiment of the present invention are opened.

FIG. 3 is a plan view showing a state after the closing blade of the camera lens shutter device according to the first embodiment of the present invention is closed.

FIG. 4 is a time chart of the first embodiment of the present invention.

FIG. 5 is a plan view showing a closed state of an open blade and a closed blade of a camera lens shutter device according to a second embodiment of the present invention.

FIG. 6 is a plan view showing a state before release of a camera lens shutter device according to a second embodiment of the present invention.

FIG. 7 is a plan view showing a state after the opening blade of the camera lens shutter device according to the second embodiment of the present invention is opened.

FIG. 8 is a plan view showing a state after closing a closing blade of a camera lens shutter device according to a second embodiment of the present invention.

FIG. 9 is a time chart of the second embodiment of the present invention.

[Explanation of symbols]

 O shutter opening 1 drive ring 2 stepping motor (actuator) 3 control circuit 4 open blade 5 closing blade 6 gear portion 7 cam portion 7a cam surface 8 pinion gear 9 locking piece 10 connecting shaft 11 fixed shaft 12 opening / closing lever 12a protrusion 13 shaft 14 Connection shaft 15 Fixed shaft 16 Opening / closing lever 16a Projection 17 Shaft 18 Connection shaft 20 Open blade 21 Open blade 22 Iris motor (actuator) 23 Close blade 24 Close blade 25 Iris motor (actuator) 26 Control circuit 27 Fixed shaft 28 Fixed shaft 29 Base plate 30 Working pin 31 Fixed shaft 32 Fixed shaft 33 Working pin

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-1-144025 (JP, A) JP-A-58-149028 (JP, A) JP-A-5-107588 (JP, A) JP-A-3-3 105334 (JP, A) Shokai 57-199319 (JP, U) Shokai 56-102524 (JP, U) (58) Fields studied (Int. Cl. ⁷ , DB name) G03B 9/08-9 / 54 G03B 9/58-9/70

Claims (1)

(57) [Claims] An opening blade for opening a shutter opening by the urging force of a spring at the time of release, a closing blade for closing the shutter opening by an urging force of the spring at the time of release, and reciprocating operation by one stepping motor . At the time of release, it operates in one direction and the open blade and front
A member for starting the closing operation of the serial closed solved suppression of blades the opening the closing blade opening operation and the blade in order, the stearate
And a control circuit for controlling the rotation of the stepping motor , wherein the control circuit applies a voltage to the stepping motor.
A lens shutter device for a camera , wherein the time from the start of the opening operation of the opening blade to the start of the closing operation of the closing blade is electrically controlled by controlling the pulse time to be performed .