JPH0659313A - Shutter - Google Patents

Abstract

PURPOSE:To make the speed of a shutter high by impressing a voltage on a piezoelectric actuator suddenly and elongating suddenly the piezoelectric actuator, so that a shutter blade may travel by making use of impact force. CONSTITUTION:When mirror-up and stop-down are finished and high level output to the output port of a microcomputer is performed; a transistor is turned on. When the transistor is turned on, charge stored in a capacitor for driving a first blind is impressed on an actuator 12 for driving the first blind. Then the piezoelectric actuator 12 for driving the first blind is elongated suddenly so that a flight hammer 16 flies out by impact, and makes a first blind driving lever 6 turn clockwise around a shaft P against a first blind reset spring 14, whereby the first blind group 2 travels. The blade driven in this way finishes acceleration by the fine displacement of a laminating type piezoelectric actuator 12 and travels against the extremely weak spring 14, so that it runs at nearly the equal speed from the beginning to the finishing of traveling.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shutter for directly driving a blade by utilizing an impact force generated when an electro-mechanical energy conversion element is displaced.

[0002]

2. Description of the Related Art Conventionally, the shutter blades of a single-lens reflex camera are often driven by a motor to urge a spring and the urging force of the spring causes the shutter blade to travel. Such a shutter using a spring as a drive source requires a mechanism for holding the blades, and also is necessary for charging a motor, a reduction gear, a cam, a lever, etc., which is complicated and large in size, and has many parts. The charging efficiency was also poor because it was charged via. For this reason, in recent years, a blade has been proposed in which the blade is directly moved by an electromagnetic force to eliminate the need for a spring charge.

Further, as a method of returning the shutter curtain to the initial position returned state in a shutter in which the shutter front curtain and the shutter rear curtain are exposed by driving in a fixed direction by an actuator such as an electromagnetic drive, a Japanese Patent Publication No. Sho 61-96019.
As described in the publication, there is a proposal made by a return spring force of a quick return mirror.

[0004]

However, in the conventional electromagnetically driven shutter, the electric power supplied from the capacity of the battery is limited, so that a sufficient curtain speed cannot be obtained and the shutter cannot be speeded up. As a countermeasure, Japanese Patent Laid-Open No. 55-19
As shown in No. 27, a method has been proposed in which the charged electric charge stored in the capacitor is provided at the initial stage of energization, but in order to increase the curtain speed, a large-capacity capacitor is required, so that the size is increased. However, since the shutter drive uses the inefficient region at the startup of the electromagnetic drive source, the efficiency is not good.

Further, in both the spring drive and the electromagnetic drive, the shutter blades always travel while accelerating from the start to the end of the run, so that as shown in FIG. Exposure has to be performed with the backlash between the levers that drive the blades, the precision of the parts, etc.
There is a problem that shutter precision unevenness and exposure unevenness are likely to occur, and in the worst case, curtain closing occurs and no exposure is performed.

On the other hand, in the conventional example of the method of returning the shutter curtain to the initial position returning state by the return spring force of the quick return mirror, a reset lever for returning the shutter curtain to the initial position and a mirror flip-up lever for driving the mirror are provided. When down, it is engaged to restore the shutter curtain,
It is necessary to prevent the engagement when the mirror is raised, which has a drawback that the mechanism is complicated and the size becomes large.

An object of the present invention is to provide a shutter which can be miniaturized with a simple structure, can achieve high accuracy, and can cope with high speed operation.

[0008]

The structure for achieving the object of the present invention is as set forth in the claims. Specifically, a piezoelectric actuator is used as an actuator for driving the shutter blades, The voltage is suddenly applied to the piezoelectric actuator, the piezoelectric actuator is rapidly extended, and the impact force is used to drive the shutter blade, so that the acceleration of the shutter blade ends with a minute displacement of the piezoelectric element, and then Since the slit speed is almost constant compared to the conventional one, the slit width is large especially at the beginning of running, so the rate of change in the slit width due to rattling between the levers that drive the blades is small, resulting in uneven exposure and uneven accuracy. It is difficult to increase the shutter speed.

Further, since the blade is directly driven by the piezoelectric actuator, the energy efficiency is high, and a motor, a gear, a lever and the like for charging the spring as in the conventional case are not required, so that the structure is simple and the size can be reduced. .

In another structure of the present invention, the shutter front curtain and the shutter rear curtain are always provided with a spring so as to have a light returning habit, and the shutter blade is driven directly against the spring by an actuator. By providing a front curtain holding lever that holds the shutter front curtain group at the traveling completion position and releases the holding of the front curtain group with the momentum of traveling of the shutter rear curtain group in the traveling end area of the shutter rear curtain group, The shutter that exposes the curtain group and the rear curtain group by driving in one direction can be returned to the initial exposure state with a simple configuration.

[0011]

1 to 4 show a first embodiment of the present invention,
1 is a state diagram of an initial position before the shutter is operated, FIG. 2 is a state in which a shutter front curtain has completed traveling and is held, and FIG. 3 is a diagram showing a state in which a shutter rear curtain has completed traveling and the front curtain is released. is there. FIG. 4 is a diagram showing an electrical configuration.

In these figures, reference numeral 1 denotes a shutter base plate, and an opening 1a is provided in the center of the base plate surface. The front curtain group 2 and the rear curtain group 3 are provided between cover plates (not shown) mounted so as to face the shutter base plate 1 so as to maintain a constant gap, and each of the two blade arms 4 and 4. 5 (the arm of the front curtain group 2 is not shown) and a known link mechanism are operated to open and close the opening 1a.

A blade drive lever 6 is connected to the blade arm 4 by a pin 6a and is rotated about an axis P,
The front curtain group 2 is driven to open and close.

The pin 6a has a front curtain holding portion 8a, which will be described later, having a corner portion so that the pin 6a can be easily held by the holding lever after traveling.

Reference numeral 7 is a trailing blade driving lever, which is a leading blade driving lever 6.
Similarly, by rotating about the axis Q, the rear curtain group 3 is opened and closed by the drive pin 7a.

Reference numeral 8 denotes a front curtain holding lever, which is a shutter base plate 1
It is pivotally supported by, is rotated about the axis O, is urged clockwise by the spring 9, and is brought into contact with the stopper 1b.

The lever 8 is bifurcated, and the front-curtain holding portion 8a protruding to the end portion of the movement trajectory of the front-curtain drive pin 6a and the trailing-curtain holding lever 8 are rotated counterclockwise by the completion of the trailing curtain movement. The release portion 8b for moving the rear curtain drive pin 7
It is projected at the end of the movement trajectory of a.

Stopper rubbers 10 and 11 are provided at the traveling end positions of the front curtain drive pin 6a and the rear curtain drive pin 7a.
The side of the drive pin hits to reduce the shock when the vehicle is completed.

Reference numerals 12 and 13 denote laminated piezoelectric actuators that generate a displacement when a voltage is applied, and are bonded and fixed to the mounting portion 1c of the shutter base plate 1, and 12 is for driving the front curtain.
Reference numeral 13 is for driving the rear curtain. The laminated piezoelectric actuators 12 and 13 are provided with weak return springs 14 and 15 so that the drive levers 6 and 7 can be returned to their initial positions. The drive levers 6 and 7 must be provided with appropriate habits in order to travel against the hood of the blades and the return springs 14 and 15, and metal flight hammers 16 and 17 are fixed.

FIG. 4 is a block diagram showing the electrical construction of this embodiment.

Reference numeral 101 is a one-chip microcomputer for controlling the camera (hereinafter abbreviated as microcomputer).
A motor driver 102 is controlled by the microcomputer 101, and drives a motor in response to a signal from the microcomputer 101. Reference numeral 103 is a motor for performing mirror up / down and film feeding, and is driven by the motor driver 102. Reference numeral 104 denotes an LCD driver, which is controlled by the control signal from the microcomputer 101.
A display is made on the panel 105.

Reference numeral 106 is a silicon photodiode,
An optical system (not shown) measures the brightness of the subject. The output of the silicon photodiode 106 is digitized by the A / D converter 107 and can be read by the microcomputer 101.
The photometry value determines the lens aperture and shutter speed.
Reference numeral 108 denotes a line sensor, which is adapted to form an image having a phase difference according to the defocus amount of the lens by an optical system (not shown). The output of the line sensor 108 is digitized by the A / D converter 109 and can be read by the microcomputer 101.

Reference numerals 115 and 116 are switches interlocked with the release button. The switch 115 is turned on at the first stroke of the release button and is switched at the second stroke.
Is turned on. The switch 115 is connected to the input port P10 of the microcomputer 101, and the switch 116 is connected to the port P11.

Reference numeral 110 denotes a DC / DC converter (not shown) which boosts the voltage of a battery as a power source and outputs a voltage of 150V. The output is supplied to the capacitor 118 via the diode 117. In the same manner, the capacitor 12 is connected via the diode 119.
It is being supplied to 0.

Reference numerals 12 and 13 denote the above-mentioned laminated piezoelectric actuators, which drive the front and rear curtains of the shutter, respectively. Reference numeral 12 is connected to the front curtain driving capacitor 118 and the collector of the transistor 113. Reference numeral 13 is connected to the rear curtain driving capacitor 120 and the collector of the transistor 114. 111 and 11
Reference numeral 2 denotes a discharge resistor, which is connected in parallel with each of the laminated piezoelectric actuators 12 and 13. The emitters of the transistors 113 and 114 are connected to the power supply ground. The bases of the transistors 113 and 114 are connected to the output ports P20 and P21 of the microcomputer 101, respectively.

The operation of this embodiment configured as described above will be described. First release button to start shooting
The switch 115 is turned on by the stroke, and the battery voltage is changed to DC.
The voltage is boosted to 150 V by the / DC converter 110, and the front curtain driving capacitor 118 and the rear curtain driving capacitor 12
It is charged to 0 and drives the lens to the in-focus position. The photometric value is obtained from the output of the silicon photodiode 106, and the shutter speed and aperture are determined and displayed on the LCD panel 105.

Next, when the release button is pushed to the second stroke, the switch 116 is turned on, and the mirror up and the focusing are started.

In FIG. 1, when mirror up and focusing are completed and a high level is output to the output port P20 of the microcomputer 101, the transistor 113 turns on. When the transistor 113 is turned on, the electric charge stored in the front curtain drive capacitor is applied to the front curtain drive actuator 12. Then, the piezoelectric actuator 12 for driving the front curtain rapidly expands, the impact causes the flight hammer 16 to pop out, and the front curtain drive lever 6 is rotated in the clockwise direction of the axis P against the front curtain return spring 14 to move the front curtain. Run Group 2. The blades driven in this way end acceleration due to a minute displacement of the laminated piezoelectric actuator and travel against the extremely weak spring, so that the blades run at substantially the same speed from the initial stage to the end.

After the front curtain group 2 is driven, the transistor 113 is turned off in preparation for the next driving, and the electric charge charged in the actuator 12 is discharged through the discharge resistor 111.

Multilayer piezoelectric actuator 1 for driving the rear curtain
Similarly to the case of the front curtain, in the case of 3, the transistor 114 is turned on after a charge is applied to the front curtain driving piezoelectric actuator 12 with a time difference according to the shutter time, and the charge is applied from the front curtain driving capacitor 120. The hammer 17 pops out, and the rear curtain group 3 runs while resisting the return spring 15.
After driving, the actuator 13 is also discharged via the discharge resistor 112.

Next, the release of the holding of the front curtain group 2 after the traveling is completed will be described with reference to FIGS. In FIG. 2, the front-curtain drive pin 6a of the front-curtain drive lever 6 travels while rotating the front-curtain holding lever 8 projecting in the locus of movement in the traveling end region around the axis O counterclockwise. The traveling of the front curtain group 2 ends when the front curtain drive pin 6a collides with the rubber stopper 10. When finished, the front curtain holding lever 8 is returned to the initial position by the spring 9, and the front curtain drive lever 6 is held at the finished position.

To release the front curtain, as shown in FIG. 3, the front curtain holding lever 8 is placed in the end region of the drive pin 7a of the rear curtain drive lever 7.
The release portion 8b of the front projection protrudes, and at the end of traveling of the rear curtain, the front curtain holding lever is rotated counterclockwise to release the front curtain, and the front curtain group 2 is moved to the initial position by the front curtain return spring 14. Make a return. The trailing blade drive lever 7 travels a little after releasing the holding of the leading blade, and then the trailing blade drive pin 7a collides with the rubber stopper, the traveling is ended, and the returning spring 15 returns the initial position. For this reason, since the front curtain group 2 performs the returning operation slightly earlier than the rear curtain group 3, the exposure is not performed during the returning operation. After the return operation is completed, the operation returns to the initial state shown in FIG. After the camera shutter travels, the mirror is down and the film is fed, and the camera sequence ends.

As described above, according to the present embodiment, as shown by the solid line in FIG. 5, the front curtain group and the rear curtain group have substantially the same speed over the entire traveling range. In comparison, the slit width becomes very large, the influence of rattling between the levers that drive the blades is reduced, and the shutter speed can be increased, which is a great advantage.

Next, FIGS. 6 to 7 show a second embodiment capable of reciprocal exposure. 18 and 19 are toggle inversion springs,
Reference numeral 12 'is a piezoelectric actuator for driving the front curtain (rear curtain in the forward path) on the return path, and 13' is a piezoelectric actuator for driving the rear curtain (the front curtain on the forward path) in the return path. With these four piezoelectric actuators, the exposure operation can be performed in the forward and backward paths, and the operation will be described. The drive levers 6'and 7'are constantly pressed by the toggle reversing springs 18 and 19 to the travel preparation position of the shutter. In this embodiment, the front curtain holding lever is unnecessary, and in the above configuration,
FIG. 6 is a view showing the forward travel preparation position of the shutter of the second embodiment, in which the drive levers 6 ′ and 7 ′ are pressed against the piezoelectric actuators 12 and 13 by toggle reversing springs 18 and 19. From this state, the drive lever is caused to travel by rapidly applying a voltage to the front-curtain driving piezoelectric actuator 12 and the rear-curtain driving piezoelectric actuator 13 in the same manner as in the first embodiment, and the forward exposure operation is performed.

FIG. 7 is a diagram showing a traveling completion state on the outward route, and also shows a traveling preparation state on the return route. From this state, similarly to the case of the exposure on the forward path, a voltage is applied to the piezoelectric actuator 12 'for driving the front curtain and the piezoelectric actuator 13' for the rear curtain on the backward path, and the shutter is moved to perform the exposure operation on the backward path. The traveling completed state is as shown in FIG. 7.

With such a structure, reciprocal exposure is possible, and there is an advantage that frame speed and super-high speed multiple continuous shooting can be performed.

[0037]

As described above, by directly driving the shutter by utilizing the impact force when the piezoelectric actuator is abruptly displaced, it is not necessary to mechanically charge the spring, and the mechanical structure is simplified. It is possible to reduce the size.

Further, since the piezoelectric actuator directly drives, very high efficiency can be obtained, and the shutter blades have a substantially constant speed over the entire traveling range, so that the slit width becomes much larger than the conventional one at the initial stage of traveling. The effect of rattling between the levers that drive the blades is reduced, and the shutter speed can be increased, which has many advantages.

[Brief description of drawings]

FIG. 1 shows a first embodiment of a shutter according to the present invention,
The figure which shows an initial position.

FIG. 2 is a diagram showing a front curtain holding state of the first embodiment.

FIG. 3 is a diagram showing a front curtain holding release state of the first embodiment.

FIG. 4 is a diagram showing an electrical configuration of the first embodiment.

FIG. 5 is a diagram showing running characteristics of the conventional shutter and the shutter of the first embodiment.

FIG. 6 is a diagram showing a second embodiment of the present invention and shows a forward route preparation position or a backward route end position.

FIG. 7 is a diagram showing a forward path end position or a backward path preparation position according to the second embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Shutter base plate 2 ... Front curtain group 3 ... Rear curtain group 6 ... Front curtain driving lever 7 ... Rear curtain driving lever 8 ... Front curtain holding lever 12 ... Front curtain driving piezoelectric actuator 13 ... Rear curtain driving piezoelectric actuator 14 ... Front curtain return spring 15 ... Rear curtain return spring 16, 17 ... Hammer 118 ... Front curtain drive capacitor 120 ... Rear curtain drive capacitor

Claims (4)

[Claims] 1. In a shutter in which a curtain member travels due to movement of a driven member, a drive source composed of an electro-mechanical energy conversion element that is displaced by applying a voltage is brought into contact with the driven member at an initial position. A shutter, wherein the shutter is disposed, and an impact force is applied to the driven member by the abrupt displacement of the driving source to cause the curtain member to travel. 2. The shutter according to claim 1, wherein a charge applied to the driving source is stored in a capacitor. 3. A front curtain group that travels by the movement of a front curtain moving member that receives the driving force of the driving means, a rear curtain group that travels by the movement of a rear curtain moving member that receives the driving force of the driving means, and the front curtain. A first-curtain biasing means for giving the group a habit of returning to the initial position,
The trailing-curtain biasing means that gives the trailing-curtain group a habit of returning to the initial position, and the leading-curtain moving member at the traveling end position of the leading-curtain group are engaged to hold the leading-curtain group. A shutter having a holding release mechanism for releasing the holding of the front curtain group by contacting with the rear curtain moving member near the end of traveling of the rear curtain group. 4. The driving means according to claim 3, wherein
The shutter is a drive source for the shutter.