JPH06194717A - Object driving device - Google Patents

Abstract

PURPOSE:To reduce the number of parts to downsize a device, and to relax the uncomfortable impulsive sound and vibration in a drive finish area by using an ultrasonic motor as a driving source for applying the braking force to an object to be driven and for charging a driving spring. CONSTITUTION:A first ultrasonic motor 6 charges a shutter front curtain driving spring (front driving spring) 8, and controls the operation of the front driving spring 8 and the speed and the restricting force (holding force) to the shutter front curtain. This front driving spring 8 is connected to a rotor 6b of an ultrasonic motor 6 directly without connection through a gear mechanism, a cam and a lever. At the time when the rotor 6b is stopped perfectly, the braking force for perfectly stopping an object to be driven is applied, and at the time when the rotor 6b can be rotated, the power generated by the front driving spring 8 is controlled by the first ultrasonic motor 6. The object to be driven is thereby made to travel at various speed and decelerated and stopped on the way of a travelling passage.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an object driving device having a spring and an ultrasonic motor, and more particularly to an object driving device suitable as a shutter device for optical equipment such as a camera.

[0002]

2. Description of the Related Art Conventionally, as a shutter device of an optical device such as a camera, for example, a shutter drive spring is charged through a gear and a cam or a lever with a known electromagnetic motor before the shutter curtain starts traveling, and then the drive spring is charged. The spring is held in a charge completed state by a tightening mechanism that suppresses the activation of the spring, and when the shutter curtain is started to run, the tightening of the spring by the tightening mechanism is released by an electromagnet, a cam, or the like. It is known that the shutter curtain is driven by the power generated by the.

In the conventional focal plane shutter described above, as shown in FIG. 16, the output of one charge driving source (for example, an electromagnetic motor) not shown is decelerated to drive the first charge lever 70 and drive the second charge lever 70. The front curtain and the rear curtain are configured to be charged almost simultaneously via the charge lever 71.

[0004]

However, the conventional shutter device described above has the following problems.

Since a known electromagnetic motor is used as a power source for charging the shutter curtain drive spring, in order to obtain a torque sufficient to elastically deform the spring, a gear mechanism having a large reduction ratio, a cam, a lever, etc. Since the power transmission mechanism must be interposed between the motor and the spring, the mechanical structure of the shutter device is inevitably complicated and large, and the manufacturing cost of the device must be high. There wasn't.

Since the traveling member (shutter curtain holding frame) integrated with the shutter curtain collides with the stopper member at a high speed at the shutter curtain traveling completion position, impact noise and unpleasant vibration are generated.

It is not possible to stop the shutter curtain in the middle of a traveling path that does not reach the stopper member, run the shutter curtain at various speeds, or decelerate the shutter curtain in the middle of traveling.

As the shutter speed increases, the driving shock of the shutter increases, which not only causes unpleasant vibrations and sounds, but also causes camera shake. In addition, since the shutter speed of the shutter is generally adjusted so as to achieve the maximum speed, the shutter curtain runs at high speed even at low speeds when the speed of the shutter speed is not so high, causing a big shock. Moreover, since it is a low-speed second, there is a problem that the camera shake is more noticeable than when it is a high-speed second.

In the above-mentioned conventional example, the reduction ratio is set large so that the charging operation can be performed reliably when the voltage of the power supply battery is low. Therefore, even if the battery voltage is high and there is room to charge the shutter, the charging operation is slow,
Therefore, the frame speed of the camera cannot be increased.

It is an object of the present invention to provide an object driving device for driving a driven object by a spring, which is lighter and smaller than a conventionally known device of this type, and moreover, the driven object is provided on the way of the traveling path. It can be stopped or decelerated, and can be driven at various speeds, and further, the driven object does not violently collide with a mechanical stopper at the end of the traveling path to generate vibration or noise,
It is to provide a novel object driving device.

[0011]

In order to achieve the above object, the object driving apparatus of the present invention uses an ultrasonic motor known as a power source for applying a braking force to the driven object and charging the driving spring. By using the (oscillating wave motor), the gear mechanism and mechanical power transmission mechanism such as cams and levers, which were required in the conventional device, are abolished, and the driven object is decelerated or stopped in the middle of the traveling path. It is possible to drive the driven object at various speeds.

Further, in the focal plane shutter constructed by applying the present invention, by providing the charge driving source for each of the front curtain and the rear curtain, the front curtain and the rear curtain are simultaneously charged when the battery voltage is high. , If the battery voltage is low, the first curtain is charged, and after the first curtain charge is completed, the second curtain is charged. By setting the first curtain and second curtain series charge, the frame speed is increased when the battery voltage is high. ,
This is to ensure that the battery can be charged even when it is low.

In the case of simultaneous charging, since the trailing curtain charging is started slightly after the start of the leading curtain charging, erroneous exposure is not performed during shutter charging. Also, since the shutter charge is performed after the film is fed, even if there is an erroneous exposure, the film already taken is protected.

Further, in order to detect erroneous exposure during charging, a front curtain charge completion signal and a rear curtain charge completion signal are provided, and an error occurs when the rear curtain charge completion signal comes before the front curtain charge completion signal. I judged that it was exposed, so I sent another frame and protected the next frame.

[0015]

In the object drive device according to the present invention, the drive spring is directly connected to the rotor of the ultrasonic motor without using a gear mechanism, a cam or a lever, and the driven object is moved when the rotor is completely stopped. A braking force to completely stop is applied, and when the rotor is rotatable, the power generated by the drive spring is controlled by the ultrasonic motor, so that the driven object is run at various speeds or the driven object is run. It is possible to decelerate and stop along the way.

Further, it is possible to realize a device which is lighter and smaller than the conventional spring type drive device and which does not generate noise or vibration.

[0017]

Embodiments of the present invention will be described below with reference to the drawings.

<First Embodiment> FIGS. 1 to 11 show an embodiment of a focal plane shutter device and a camera to which the object driving device of the present invention is applied.

FIG. 1 is a perspective view of the focal plane shutter of this embodiment, and FIG. 2 is a sectional view of the focal plane shutter.

In the figure, 1 is a shutter base plate,
An exposure window 1a is provided substantially in the center of the plane. Reference numeral 2 is a cover base plate attached to the shutter base plate 1 so as to maintain a constant gap, and has an exposure window (not shown) at a position corresponding to the exposure window 1a.

A front curtain group 3 and a rear curtain group 4 are provided between the shutter base plate 1 and the cover base plate 2, and the exposure window is opened and closed by a known link mechanism.
Further, a partition plate 5 is provided between the front curtain group 3 and the rear curtain group 4 in order to prevent the interference.

Numeral 6 is a first USM for charging the shutter front curtain drive spring and controlling the operation of the spring and the speed and restraining force (holding force) of the shutter front curtain.
(Ultrasonic motor), 12 is a second for charging the shutter rear curtain driving spring and controlling the operation of the spring, the speed with respect to the shutter rear curtain, and the restraining force (holding force).
It is USM. Although the USM is already known, its function and operation are completely different from those of known electromagnetic motors. Therefore, the function and operation of the USMs 6 and 12 will be described below with reference to FIGS. 3 to 6. .

FIG. 3 is a diagram showing an electrical configuration for driving the USM. A microcomputer 204 controls the USM and outputs a control signal. Reference numeral 205 denotes a known USM driving device, which includes a D / A converter, a VCO, a phase shifter, an amplifier and the like. USM is vibrator 201, rotor 202, USM
It is composed of a fixing member 203. The case where a traveling wave and a standing wave are generated in a USM oscillator will be described below.

Traveling wave: When a traveling wave is generated from the USM driving device 205 to the USM vibrator 201 by a control signal from the microcomputer 204, the USM rotor 202 can be rotated at an arbitrary direction and speed. Speed control can be performed by changing the drive frequency.

Standing wave: When a standing wave is sent to the USM vibrator 201, a U signal is sent by a control signal from the microcomputer 204.
The SM drive unit 205 converts the two-phase signals into the same phase, and the oscillator 2
Send to 01. Moreover, the amplitude of the standing wave can be controlled by changing the frequency.

The resistance force when the rotor 202 is rotated from the outside changes depending on the amplitude of the standing wave generated in the vibrator 201. The resistance of the rotor 202 will be described.

1. The amplitude of the standing wave and the resistance force when the rotor is rotated from the outside are as shown in FIG. 4, and the maximum resistance force with an amplitude of 0 is the holding torque. The resistance decreases as the amplitude increases.

2. Next, as for the relationship between the drive frequency and the amplitude, as shown in FIG. 5, the amplitude is 0 up to the resonance frequency, the amplitude becomes maximum at the resonance frequency, and the amplitude becomes smaller when the frequency becomes higher than that. Thus the relationship of the resistance force when turning the rotor from the drive frequency and the external is as shown in FIG. 6, the resonant frequency f _n to become 0 in the vicinity of the resonance frequency f _n at maximum resistance force is gradually resistance becomes a more The power grows.

In the present invention, by utilizing such characteristics of USM, the rotor 202 is generated while the traveling wave is generated in the oscillator 201 and the spring is charged by the rotor 202.
To drive. The traveling wave to the oscillator 201 is stopped when the spring is brought to the charging completed state. At this time, the resistance force when the rotor 202 is rotated from the outside is maximized, the holding torque is generated at the stop position, and the rotor 202 is not returned by the spring force.

In this state, when the rotor 202 is driven, the resistance force is almost equalized by causing the oscillator 201 to generate a standing wave with a frequency f ₁ slightly higher than the resonance frequency f _n of FIG. It becomes 0, and the shutter curtain, which is the driven object, can be driven by the charged spring force. Further, the driving speed is suppressed by generating a standing wave having a frequency of f ₂ which is higher than f ₁ , or a standing wave having a frequency of f ₁ is generated at the beginning, and f ₂ is generated near the end of driving. A braking effect can also be obtained by switching to the standing wave of the frequency of. Also, change the frequency from f ₁ to f ₂
Gradually change to a shock due to sudden braking or U
The load applied to the SM may be reduced.

Here, the structure of the shutter device according to the present embodiment will be described with reference to FIGS. 1 and 2 again.

Reference numeral 6 denotes the above-mentioned pre-driving USM (ultrasonic motor for controlling the shutter front curtain driving spring), which is composed of a vibrator 6a, a rotor 6b, and a USM fixing member 6c.
Is fixed with screws 7 concentrically with the drive of the front curtain. A front curtain drive spring 8 for driving the front curtain group 3 is arranged around the rotor 6b for downsizing.

The front curtain drive spring 8 is a front curtain drive arm portion 6 formed integrally with the ratchet 9 for adjusting the curtain speed and the rotor 6b.
b ₁ and is urged to rotate the front curtain drive arm portion 6 b ₁ clockwise.

A front curtain drive pin 6b ₂ for interlocking the front curtain group 3 when the rotor 6b rotates is planted in the rotor 6b.

Further, the rotor 6b is provided with a brush 10 for detecting the rotation angle of the rotor 6b. 11
Is a front curtain phase substrate, the phase pattern is plated, and the contact with the brush 10 causes the front curtain drive arm portion 6b.
_It detects the rotation angle of ₁ . Ratchet 9
Is rotatably supported and is locked by a stop tab (not shown) to adjust the blade traveling speed.

Reference numeral 12 is a rear curtain drive spring charging ultrasonic motor, which comprises a vibrator 12a, a rotor 12b, and an ultrasonic motor fixing member 12c. The front drive USM 12 is concentric with the drive link of the rear curtain by a screw 7. It is fixed. Rear curtain side are configured similarly to the front curtain side, the rear curtain drive pin 12b ₂ are provided with the rear curtain drive arm portion 12b ₁ on the rotor 12b, blade driving spring 1 after having been subjected around the rotor 12b
3, the trailing blade drive arm portion 12b ₁ is biased in the clockwise direction. Reference numeral 14 is a brush disposed on the rotor 12b, and detects the rotation angle of the trailing blade drive arm portion 12b ₁ by contacting with the trailing blade phase substrate 15. 7 and 8 are enlarged plan views of the front curtain phase substrate 11 and the rear curtain phase substrate 15. GND patterns 11a and 15a for supplying the GND potential to both the front and rear sides of the substrate and a charge completed (running preparation) state. There are patterns 11b and 15b for detecting the travel, patterns 11c and 15c for detecting a brake signal immediately before the end of travel, and patterns 11d and 15d for detecting the completion of travel. The detection is determined by whether or not the GND potential is conducted by the contact between the pattern of b, c, d and the brush 10 and the brush 14, and the non-conducting state is set to Hi level and the conducting state is set to Lo level. The phase is detected by detecting the Lo level.

FIG. 7 shows the charge completion state (start preparation position) on both the front curtain side and the rear curtain side, and shows the state where the charge completion signal patterns 11b and 15b are detected.

FIG. 8 shows a traveling completion signal pattern 11 on the front curtain side.
The second curtain and the rear curtain show the state in which the pattern 15d is detected.

FIG. 9 is a block diagram showing the control circuit of a camera equipped with the shutter device of this embodiment.

Reference numeral 100 is a photometric switch which is turned on by the first stroke of a release button (not shown). 101 is a release switch that is turned on by the second stroke of the release button.
The signals of these switches 100 and 101 are input to a microprocessor (MPU) 102. This MPU1
Reference numeral 02 denotes a front curtain charge completion signal 11b and a front curtain brake signal 11 of a detection pattern for detecting the rotation angle of the rotor of the ultrasonic motor and detecting the position of the shutter blade.
c, front curtain running completion signal 11d, rear curtain charging completion signal 1
5b, rear curtain brake signal 15c, rear curtain running completion signal 15
The film feed signal 103 is also input from d and the film feed detection means (not shown). With respect to the photometry circuit 104 and the distance measurement circuit 105, the MPU 102 sends operation timing information and transfers the respective outputs to the MPU 102. The mirror drive motor 108 and the film feeding motor 109 have forward and reverse energization drive, and a bridge circuit capable of switching to an electric brake state forming a short circuit.

The leading curtain USM driving device 110 and the trailing curtain USM driving device 1 are respectively provided for the leading driving USM6 and the trailing driving USM12.
11, the front curtain USM drive device 110 and the rear curtain USM drive device 111 are D / A converter, VCO, phase shifter,
It consists of an amplifier.

When the shutter is operated, the MPU1
In response to the signal 02, the front curtain USM drive device 110 generates a standing wave on the vibrator 6a of the front drive USM 6 to cancel the holding force, and the front drive spring 8 precharged causes the front curtain group 3 to travel. MPU after a predetermined shutter time
The signal of 102 causes the trailing blade USM driving device 111 to generate a standing wave in the vibrator 12a of the trailing driving USM 12 to cancel the holding force, and the trailing blade group 4 is caused to travel by the trailing curtain spring charged in advance.

When charging the shutter, MP
The drive springs 8 and 13 are charged by generating traveling waves from the front and rear curtain USM drive devices 110 and 111 in response to the signal of U102 to the vibrators 6a and 12a of the rear drive USMs 6 and 12, respectively.

There is no mechanical connection between the photographing lens (not shown) and the camera body, and there is no mechanical connection between the camera body side MPU 102 and the lens control circuit 112, and there is no camera body side MPU 102 and lens control. Only electrical communication with the circuit 112. However, the power supply for driving the photographing lens side is supplied from the camera body side.

The taking lens is an aperture driving actuator 1.
13. The focus driving actuator 114 is uniquely provided, and the MPU 102 commands the drive timing to drive the focus control actuator 112 via the lens control circuit 112.

Next, the operation of the focal plane shutter of this embodiment will be described. First, the leading blade group 3 and the trailing blade group 4 are first and second driving U in a state where the leading driving spring 8 and the trailing driving spring 13 biased clockwise as shown in FIG. 7 are charged.
It is held in the charging completed state by the holding force of the SM. The MPU 102 associated with the release operation is the first USM
A standing wave having a frequency f ₁ slightly higher than the resonance frequency f _n is generated in the vibrator 6a of the USM 6 that is driven earlier than the driving device 111.

From FIG. 6, the resistance force at this frequency f ₁ is almost 0, the spring force of the front drive spring 8 causes the front drive arm portion 6b ₁ to start rotating clockwise, and the front curtain group 3 also has the front curtain. Driven by drive pin 6b ₂ . The front curtain group 3 gradually increases in speed, and if it collides with the stopper as it is, an uncomfortable shock or sound is generated in the camera. Therefore, in the present embodiment, when the rotation angle is detected by the contact between the brush 10 arranged on the rotor 6b and the front curtain phase substrate 111, and the front brake signal 116 provided immediately before the end of traveling is detected, MP
U102 is a USM6 drive ahead of the USM drive unit 111
Higher f ₂ in further 6 than f ₁ the vibrator 6a of
Generates a standing wave with a frequency of.

Since the resistance force at f ₂ is considerably larger than the resistance force at f ₁ , the rotor 6b is braked and the collision speed of the front curtain group and the front drive arm portion 6b ₁ against the stopper is slowed. As a result, camera shake and unpleasant shock can be reduced.

When the preceding traveling completion signal 11d is detected, the generation of the standing wave is ended, and the bouncing is prevented by the stop torque of the USM. Next, the MPU 102 moves to the rear USM driving device 112 with a shutter second time interval after the first curtain starts driving.
A standing wave of frequency f ₁ is generated in the vibrator 12a of the rear-driving USM 12 as in the case of the front curtain. Then, the holding torque becomes almost 0, and the rear drive arm portion 12b ₁ is rotated clockwise by the spring force of the rear drive spring 13 to drive the rear curtain group 4. By varying detects the trailing curtain brake signal 15c trailing curtain in front curtain as well as travel immediately before the end of the standing wave frequency to be generated in the oscillator USM from f ₁ to f _2, brake. When the post-travel completion signal 15d is detected, the standing wave is terminated and the USM holding torque prevents the bouncing.

Further, when the shutter is at low speed seconds, sufficient shutter accuracy can be obtained even if the curtain speed is slow, and camera shake is more likely to occur on the low speed seconds side as compared to the high speed seconds side. , It is desirable to be slow to some extent.

In the present invention, the USM vibrator is loaded with the frequency f shown in FIG.
By generating a standing wave such as ₂ and using a place with a relatively large resistance, the running speed of the shutter curtain was suppressed.

[0052] The shutter curtain brakes, although the frequency of the standing wave is generated from the detection of the brake signal to the vibrator of the USM is abruptly changed from f ₁ to f _2, sudden braking force when the The impact may be added by USM
In some cases, a large load may be applied to the oscillator, and the standing wave generated in the oscillator of the USA may be gradually changed to gradually increase the resistance force.

When the end of the trailing curtain is detected, the film feeding motor 107 is energized to feed the film. This is to feed the film before the shutter charge in order to protect the film already photographed even if there is an erroneous exposure during charging which will be described later.

After the film is fed, the shutter charge is started. In the case of the present invention, since there are two independent USMs as the charge source for the leading blade and the trailing blade, when the battery voltage is high and the amount of electric power that can be drawn is large, simultaneous charging is performed to emphasize the frame speed and the battery voltage can be drawn low. Even when the amount of electricity is small, the first and second curtains can be charged in series to ensure reliable charging even when the voltage is low. However, in the case of simultaneous charging, if the trailing curtain is charged first, the exposure is erroneous during the charging operation. Therefore, the charging of the leading curtain is started and the trailing curtain is charged with some timer. Furthermore, in the unlikely event that the front curtain charge completion signal 11b, the rear curtain charge completion signal 15
If b comes earlier, it is determined that the film was erroneously exposed during charging, the film feeding motor 107 is energized, and another frame is fed to protect the film of the frame to be photographed next time. There is no erroneous exposure on the frame.

Next, the operation of shutter charge by USM will be described.

Previous USM drive USM111 is MPU10
2 to receive a signal from the drive unit 2 and cause the oscillator 6a of the pre-driving USM 6 to generate a traveling wave. The rotor 6b rotates counterclockwise while resisting the front drive spring 8 that is urged clockwise by the rotor 6b. The trailing blade side causes the traveling wave to be generated in the vibrator 12a of the trailing drive USM 12 slightly behind the leading blade side, and rotates the rotor 12b counterclockwise while resisting the trailing drive spring 13. When the brush 10 attached to the front curtain drive arm portion 6b ₁ comes into contact with the front curtain phase substrate 11 and detects the front curtain charge completion signal 11b, the generation of the traveling wave to the vibrator 6a is stopped. At this time, the spring force of the drive spring 8 is US
Since the holding torque when M is stopped is smaller than the holding torque, the front curtain group 3 and the front driving arm portion 6b ₁ are held at the charge completion position.

Similarly, on the trailing curtain side, the trailing charge completion signal 16b is generated.
When it detects that, the generation of the traveling wave to the vibrator 12a is stopped,
The holding torque of USM holds the trailing blade group 4 and the trailing drive arm portion 12b ₁ at the charge completion position.

In the above charging operation, the frame speed is increased by simultaneously charging the front curtain and the rear curtain when the battery voltage is above a certain level.

If the battery voltage is less than a certain value and it is impossible to drive two charge drive sources simultaneously, first drive USM6.
Drive the front drive spring 8 to detect the front curtain charge completion signal 11d, and then drive the rear drive USM to charge the rear drive spring 13 to ensure the shutter charge even when the battery voltage is low. I can do it.

Next, the operation of the camera of this embodiment having the configuration of FIG. 9 will be described based on the flowchart shown in FIG.

In step (hereinafter abbreviated as S) -1, when the power switch (not shown) is turned on and the photometric switch is turned on (S-2), the wakeup operation (S-
3) is performed, and a DC / DC converter (not shown) is operated to put various circuits into an operating state.

Next, the photometering circuit 104 and the distance measuring circuit 105 are operated to determine the aperture when the shutter speed is set (S-
4). The focus driving actuator 114 of the photographing lens is operated based on the distance measurement information to start the focus driving (S-5).

If the release switch 101 is not turned on in S-6, the lens focus drive of a predetermined amount is completed (S-7), the process returns to S-4, and the photometry and distance measurement operations are performed. If the release switch 101 is turned on during this time, the lens focus drive is stopped (S-8), and the shooting sequence starts. In this embodiment, the lens focus drive is stopped halfway when the release switch 101 is turned on, but it is also possible to drive the lens by a predetermined amount before proceeding to the shooting sequence.

Further, depending on the distance measuring state, it may be prohibited to proceed to photographing.

In S-9, it is determined whether the shutter speed determined in (S-4) is high speed or low speed. If the shutter speed is higher than the predetermined time, the TvHi flag is set (S-10), and if the shutter speed is lower than the predetermined time, the TvLo flag is set (S-11).

The battery is checked in S-12,
If it is higher than the predetermined voltage, the BCHi flag is set (S-13), and if it is lower than the predetermined potential, the BCLo flag is also set (S-14).

In S-15, the mirror drive motor 108
Energize to start mirror up.

At S-16, the lens focusing is started. At this time, to avoid overlapping of rush currents (S-1
It is desirable to slightly delay it compared to 5).

The lens narrowing down is completed (S-17),
When the mirror raising is completed (S-18), the shutter is driven (S-19). Details of driving the shutter will be described later.

When the driving of the shutter is completed, the mirror down operation is started (S-20) and the lens diaphragm opening operation is started (S-21). The lens diaphragm is opened (S-22),
When the mirror down is completed (S-23), film winding is started (S-24). The reason for feeding the film before performing the shutter charge is that, in the case of the present embodiment, since the front curtain and the rear curtain have charge drive sources,
During the charging operation, there is a possibility that the trailing curtain will be charged first, and in that case, the exposed film is re-exposed and the film is ruined.

For the purpose of preventing such an accident, the photographed film is fed before the shutter charge operation to prevent re-exposure of the photographed film.

When the film winding is completed (S-2
5), B. It is determined whether the C flag is Hi or Lo (S-2
6). B. When it is determined that the C flag is Hi, simultaneous charging is performed to increase the frame speed, and when Lo is Lo, the leading and trailing curtains are driven in series so that charging can be performed even when the battery capacity is low. First, the case of simultaneous charging will be described.

In step S-27, the pre-driving USM 6 is driven to start charging the pre-driving spring 8. Wait 10 ms from the start of driving the pre-driving USM6 (S-28), and then drive the post-driving USM6.
M12 starts driving and charging of the rear driving spring 13 starts.

A 10 ms timer is provided in order to prevent the trailing curtain from overtaking the leading curtain to cause erroneous exposure during charging. However, even if a timer is provided, there is a possibility of erroneous exposure, so it is detected whether the trailing-curtain charge completion signal 15b comes first (S-30) or the leading-curtain charge completion signal 11b comes first (S- 31) If the rear-curtain charge completion signal 15b is detected first, it is determined that the rear-curtain overtakes the front-curtain and is erroneously exposed during charging.

First, the case where the front curtain charge completion signal 11b is detected first will be described. When the front curtain charge completion signal 11b is detected, the drive of the front drive USM6 is stopped (S-32).

Next, when the trailing curtain charge completion signal 15b is detected (S-33), the driving of the trailing drive USM 12 is stopped (S-34), and one camera sequence is completed (S-).
46).

When the trailing-curtain charge completion signal 15b is detected before the leading-curtain charge completion signal 11b, it is determined that the exposure is erroneous (S-30), and the driving of the trailing drive USM 12 is stopped. Next, when the front curtain charge completion signal 11b is detected (S-36), the drive of the front drive USM 12 is stopped (S-37). Next, the winding of the film that was erroneously exposed during charging is started (S-38), and one frame is fed. In this way, the next photographic film can be protected by sending another frame that has been erroneously exposed by charging. When the winding of one frame is completed (S-39), one camera sequence is completed.

Next, in S-26, B.I. A case where the C level is Lo will be described. At this time, since the pre-driving USM6 and the post-driving USM12 cannot be simultaneously driven due to the battery capacity, they are charged in the first and second series.

First, in S-40, the pre-driving USM6 is driven,
The charging of the front drive spring 8 is started. When the front curtain charge completion signal 11b is detected (S-41), the front drive USM
The driving of No. 6 is stopped (S-42). Then the post drive USM
12 is driven to start charging the rear drive spring 13 (S-43). When the trailing curtain charge completion signal 15b is detected (S-44), the driving of the rear driving USM12 is stopped (S-45), and one sequence of the camera is ended (S-).
46).

The shutter driving in S-19 will be described with reference to the flowchart shown in FIG.

First, it is determined whether the shutter speed is Lo level or Hi level (# 1). Therefore, at the Hi level, the holding torque of the pre-driving USM6 becomes almost 0 by generating the standing wave of the frequency f _{1 in} the vibrator 6a of the pre-driving USM6, and the pre-charged spring force of the pre-driving spring 8 causes the front curtain to move. Run group 3 (# 2). At the same time, the shutter timer is started (# 3). The shutter time elapsed (# 4) and the front curtain brake signal 11c (#
Determine which of 5) comes first. When the front curtain brake signal 11c comes first, a standing wave of frequency f ₂ is generated in the vibrator 6a of the front drive USM 6. Then, the resistance force of rotating the front drive USM6 becomes large, and it works as a brake for the front curtain traveling (# 6). Next, it is determined again whether the shutter time elapses (# 7) or the front curtain travel completion signal 11d (# 8) comes first. When the front curtain running completion signal 11d comes first, the generation of the standing wave to the vibrator 6a of the pre-driving USM 6 is stopped (# 9). Then, a holding torque is generated in the front drive USM 6, and it is possible to suppress the bound of the front curtain group 3.

Until the shutter time elapses (# 10)
Waiting, after the shutter time has elapsed USM after drive
Twelve oscillators 12a generate a standing wave of frequency f ₁ ,
The holding torque of the rear drive USM 12 becomes almost 0, and the rear curtain group 4 is caused to travel by the spring force of the charged rear drive spring 13 (# 11).

When the trailing curtain brake signal 15c is detected (#
12), the frequency f ₂ is applied to the vibrator 12a of the post-drive USM12.
Generates standing waves. Then, the resistance of the rear drive USM12 becomes large and works as a brake for the rear curtain running (# 1
3).

When the trailing curtain running completion signal 15d is detected (#
14) Then, the generation of the standing wave in the vibrator 12a of the post-drive USM 12 is stopped (# 15). When the rear drive USM 12 is stopped, a holding force is generated, so that the bouncing of the rear curtain group 4 can be suppressed. Then go to (S-20).

Next, in (# 4), description will be given when the shutter time has elapsed.

A standing wave having a frequency f ₁ of the rear drive USM 12 is generated to drive the rear curtain group 4 by the rear drive spring 13 (# 16).

When the front curtain brake signal 11c is detected (#
17), a standing wave of frequency f ₂ is generated in the vibrator 6a of the pre-driving USM 6 and the brake is applied (# 18).

It is detected which of the front curtain running completion signal 11d (# 19) and the rear curtain brake signal 15d (# 20) comes first, and when the rear curtain brake signal 15c comes first, the rear drive USM12. A standing wave of frequency f ₂ is generated in the vibrator 12a of No. 2 and used as a brake for the trailing curtain travel (# 21). When the front curtain traveling completion signal 11d is detected (# 22), the generation of the standing wave on the vibrator 6a of the front drive USM 6 is stopped (#
23) The running of the front curtain is stopped by the holding torque.

When the trailing-curtain traveling completion signal 15d is detected in (# 24), the standing wave is stopped from being generated in the vibrator 12a of the rear-driving USM 12 (# 25), and the traveling of the trailing curtain is stopped by the holding torque. Then go to (S-20).

At (# 19), the leading curtain traveling completion signal 11
When d is detected first, the generation of the standing wave of the vibrator 6a of the pre-driving USMb is stopped (# 26).

When the rear curtain brake signal 15c is detected, a standing wave of frequency f ₂ is generated in the vibrator 12a of the rear drive USM 12 (# 28), and the rear curtain is braked.

When the trailing curtain running completion signal 15d is detected (# 29), the generation of standing waves on the vibrator 12a of the rear driving USM 12 is stopped (# 30), and the trailing curtain is stopped running. Then go to (S-20).

When the shutter time has elapsed in (# 7), a standing wave of frequency f ₁ is generated in the vibrator 12a of the rear drive USM 12 to cancel the holding force of the rear drive USM 12, and the rear drive spring 13 The trailing curtain group 4 is caused to travel by the spring force (# 26).

The traveling completion signal 11d of the front curtain is detected (#
27) and the generation of standing waves on the vibrator 6a of the pre-driving USM 6 is stopped, and the driving of the front curtain is stopped (# 28).

When the trailing curtain brake signal 15c is detected (#
29), a frequency f ₂ is applied to the vibrator 12a of the post-drive USM12.
To generate a standing wave and brake the rear curtain (# 3
0).

When the trailing curtain running completion signal 15d is detected (#
31), the generation of standing waves on the vibrator 12a of the rear drive USM 12 is stopped, and the traveling of the rear curtain is stopped (# 32). Then go to (S-20).

When the Tv flag is Lo in (# 1), since it is a low speed second, sufficient accuracy can be obtained even if the curtain speed is low, and the camera shake is likely to occur due to the low speed.
It is desirable to reduce the curtain speed. So at low speeds, U
From the beginning, the SM oscillator was used at a relatively large resistance such as the frequency f ₂ .

The vibrator 6a of the pre-driving USM6 in (# 33)
To generate a standing wave of frequency f ₂ . Then drive ahead US
The holding torque of M6 is reduced, and the front curtain group 3 starts to run by the pre-driving spring 18 that has been charged in advance.
At the same time, start the shutter timer (#
34).

When the front curtain running completion signal 11d is detected (#
35), the generation of standing waves on the vibrator 6a of the pre-driving USM 6 is stopped, and the traveling of the front curtain is stopped (# 36).

Next, wait for the shutter second time (# 37),
A standing wave having a frequency f ₂ is generated in the vibrator 12a of the rear drive USM12, and the holding torque of the rear drive USM12 decreases.
The trailing blade group 4 is caused to travel by the trailing drive spring 13 charged in advance (# 38).

When the trailing curtain running completion signal 15d is detected (#
39), the generation of standing waves on the vibrator 12a of the rear drive USM 12 is stopped, and the traveling of the rear curtain is stopped (# 40).

In the case of a low speed second, it is considered only when the front curtain group 3 and the rear curtain group 4 do not form a slit, but the slit may be formed. From (# 40) to (S-2
Go to 0).

<Second Embodiment> Next, a mirror driving mechanism utilizing the present invention will be described with reference to FIGS.

In FIG. 12, 51 is a mirror box,
It is fixed to a camera body (not shown) by mounting portions 51a and 51b. 52 is a mirror holder, and the mirror 5
3 is fixed, and a rotary shaft 54 is fixed to one end thereof, and the rotary shaft 54 is rotatably supported by holes 51c and 51d provided on both side surfaces of the mirror box 51, respectively.
Reference numeral 55 denotes an eccentric pin, which is adjustably projected on one side surface of the mirror box 51, and serves as a stopper which contacts the mirror holder 52 and determines the angle of the mirror 53 at the lowered position. Reference numeral 56 denotes a sector gear, which is fixed to one end of a drive shaft 54 protruding outside one side surface of the mirror box 1, and a spring 57 is hooked on the sector gear 56 and one side surface of the mirror box 51. It is always biased downward. Reference numeral 58 is a vibrator 58a and a rotor 58b
The USM is composed of the USM and is supported by the camera body, and the gear 59 provided on the rotation shaft thereof meshes with the sector gear 56. Position detection switches 60 and 61 are arranged in the camera body so as to be closed by the sector gear 56 immediately before the mirror lowering completion position and immediately before the mirror raising completed position, respectively. A stopper pin 62 is planted on the inner surface of one side surface of the mirror box 51 so as to come into contact with the mirror 53 when the mirror is raised.

FIG. 14 is a diagram showing the electrical construction of the second embodiment. The USM drive unit 503 comprises a known D / A converter, VCO, phase shifter, amplifier and the like. Signals from the release switch 502 and the position detection switches 60 and 61 are input to the microcomputer 501. USM58 is US
It is driven by a signal from the microcomputer 501 via the M drive device 503.

The operation of the second embodiment having the above configuration will be described.

In the subject observation state before release, the mirror 5
Reference numeral 3 is in the lowered position as shown in FIG. 13 so as to guide the incident light to the finder optical system.

Next, at the time of photographing, when the release switch is turned on by the release operation, the mirror 53 is moved up, so that the USM drive device 503 generates a traveling wave on the oscillator 58a of the USM58 by the signal from the microcomputer 501. Rotate counterclockwise. Then, the sector gear 56 raises the mirror 53 via the gear 59 against the biasing force of the spring 57. As shown in FIG. 13, when the mirror 53 is lifted up to just before the completion of the lift, the sector gear 56 closes the position detection switch 60.

The USM 58 is driven until a predetermined time elapses after the position detection switch is closed. This is a timer in which the mirror 53 contacts the stopper pin 62 and guarantees a completely up state. After a certain period of time, US
Stop driving M58.

Since the holding torque of the USM is larger than the force of the spring 9 for lowering the mirror 53, the mirror is held in the mirror raised state until the photographing is finished in the mirror raised state.

When the photographing is completed, the USM driving device 503 causes the USM58 vibrator 5 to respond to the signal from the microcomputer 501.
A standing wave having a frequency f ₁ slightly higher than the resonance frequency f _n as shown in FIG. 6 is generated in 8a to make the holding torque almost zero. Then, the spring force of the spring 9 becomes larger, and the mirror 53 starts descending.

Immediately before the completion of the lowering of the mirror, the position detection switch 6
When 1 is closed by the sector gear 56, the microcomputer 50
In response to the signal from 1, the USM drive device causes the oscillator 58a of the USM 58 to generate a frequency with high resistance, such as the frequency f ₂ shown in FIG. I get a braking effect by it,
Relieves impact force.

A standing wave of frequency f ₂ is generated in the vibrator 58a for a predetermined time after the position detection switch 61 is turned on. This is a timer for ensuring that the mirror 53 is completely lowered. After a predetermined time has passed, the microcomputer 50
The signal from 1 stops the generation of the standing wave of USM58.

FIG. 15 is a graph showing the descending operation of the mirror 53 of the present embodiment. In the conventional case, the mirror 53 collides with the stopper at high speed and bouncing occurs. However, according to the present embodiment, there is almost no bounce and the collision noise is small.

Although the focal plane shutter and the mirror drive have been described in the embodiments, the present invention can be applied to any drive mechanism, especially a reciprocating drive mechanism.

[0116]

As described above, in the object drive device of the present invention, the drive spring is charged by the USM and held at the charge completion position (travel preparation position) by the holding torque of the USM, and the drive member travels. Has a structure in which the holding torque is canceled by generating a standing wave in the USM oscillator and the traveling is performed by the spring force of the drive spring, so the structure is simplified, the number of parts is reduced, and downsizing is possible. Become. Also, by changing the frequency of the standing wave generated in the USM oscillator immediately before the end of the drive of the drive member, the resistance force is increased and a braking effect is provided, so that an unpleasant impact sound or vibration is generated in the drive end region. Can be relaxed.

Further, the driving speed can be easily suppressed by changing the frequency of the standing wave generated in the USM oscillator.

Since the frequency generated in the USM vibrator can be electrically controlled, the braking force can be freely controlled.

Further, when the object driving apparatus of the present invention is applied to the focal plane shutter of a camera, since the front curtain and the rear curtain are each provided with a charge drive source as in the above-mentioned embodiment, When the battery voltage is high, it is possible to drive them simultaneously to increase the frame speed, and even when the battery voltage is low, the front and rear curtains can be reliably charged by charging them in series.

When charging the first and second curtains at the same time,
It is possible to prevent erroneous exposure during charging by slightly delaying the start of the rear curtain charging to the front curtain charging.

Since the shutter is charged after the film is fed, even if there is an erroneous exposure during charging, the frames that have been photographed can be protected.

Further, by providing a front curtain charge completion signal and a rear curtain charge completion signal, erroneous exposure during charging can be detected, and when erroneous exposure is detected, another frame film is sent. The next frame can be protected.

USM immediately before the shutter curtain finishes traveling
By changing the frequency generated in the vibrator, the resistance is increased to provide the braking effect, so that the running shock, vibration, impact sound, and camera shake of the shutter curtain are significantly reduced. There are many advantages such as stopping the generation of the USM standing wave when the shutter curtain has finished running and suppressing the bounce with the USM holding torque.

Also, at low speed seconds where camera shake is likely to occur, it is possible to suppress the curtain speed by changing the frequency generated in the USM oscillator.

[Brief description of drawings]

FIG. 1 is a perspective view of a focal plane shutter according to a first embodiment of the present invention.

FIG. 2 is a sectional view of the focal plane shutter according to the first embodiment of the present invention.

FIG. 3 is a diagram showing an electrical configuration of a known USM.

FIG. 4 is a diagram for explaining the relationship between the amplitude of a standing wave and the resistance force in USM.

FIG. 5 is a diagram for explaining the relationship between the frequency and amplitude of a standing wave in USM.

FIG. 6 is a diagram for explaining the relationship between the frequency of a standing wave and resistance in USM.

FIG. 7 is a diagram showing a charge completed state of the first embodiment shown in FIG.

FIG. 8 is a diagram showing the shutter running state of the first embodiment shown in FIG.

9 is a diagram showing an electrical configuration of a camera having the focal plane shutter of FIG.

10 is a flowchart of the operation of a camera having the focal plane shutter of FIG.

11 is a flowchart showing the operation of the focal plane shutter shown in FIG.

FIG. 12 is a diagram showing a mirror descending state according to the second embodiment of the present invention.

FIG. 13 is a diagram showing a mirror raised state according to the second embodiment of the present invention.

FIG. 14 is a diagram showing an electrical configuration of a second embodiment of the present invention.

FIG. 15 is a diagram showing a mirror lowering operation according to the second embodiment of the present invention.

FIG. 16 is a front view of a conventional focal plane shutter.

[Explanation of symbols]

1 ... Shutter base plate 3 ... Front curtain group 4 ... Rear curtain group 6a ... Oscillator 6b ... Rotor 8 ... Lead drive spring 11 ... Lead curtain phase substrate 12 ... Rear drive US
M 12a ... Oscillator 12b ... Rotor 13 ... Rear drive spring 15 ... Rear curtain phase substrate 51 ... Mirror box 56 ... Sector gear 57 ... Spring 58 ... USM 58a ... Transducer 58b ... Rotor 60, 61 ... Position detection switch 110 ... First Curtain US
M drive device 111 ... Rear curtain USM drive device

Claims (15)

[Claims] 1. A spring that applies a driving force to a driven object, a spring charge drive source that charges the spring, an ultrasonic motor that applies a restraining force to the object, and a control unit that controls the ultrasonic motor. The control means holds the driven object in a stopped state with a stop holding torque of the ultrasonic motor by restraining the rotor of the ultrasonic motor when the charging of the spring is completed,
An object driving apparatus having a function of causing the ultrasonic motor to release a stop holding torque when driving the driven object. 2. A spring which applies a driving force to a driven object, an ultrasonic motor which charges the spring and applies a restraining force to the object, and a control means which controls the ultrasonic motor. The control means holds the driven object in a stopped state by the stop holding torque of the ultrasonic motor by restraining the rotor of the ultrasonic motor when the charging of the spring is completed,
An object driving apparatus having a function of causing the ultrasonic motor to release a stop holding torque when driving the driven object. 3. The object drive device according to claim 1, wherein the control means has a function of causing a standing wave to be generated in the ultrasonic motor when the driven object is driven. 4. The object according to claim 1, wherein the control means has a function of changing the frequency of a standing wave generated in the motor immediately before the end of driving the driven object. Drive. 5. The object driving device is configured as a shutter driving device of an optical device, and the shutter driving device charges a first spring that gives a driving force to a shutter front curtain and the first spring. A first spring charge drive source, a first ultrasonic motor for applying a restraining force to the shutter front curtain, a second spring for applying a drive force to the shutter rear curtain, and the second spring are charged. A second spring charge drive source, a second ultrasonic motor for applying a restraining force to the shutter rear curtain, and a control means for controlling each of the first and second ultrasonic motors. A shutter drive device characterized in that 6. The first ultrasonic motor also serves as the first spring charge drive source, and the second ultrasonic motor also serves as the second spring charge drive source. A function of causing the second ultrasonic motor to charge the second spring after the charging of the first spring is completed by the first ultrasonic motor. The shutter drive device according to claim 5. 7. The first ultrasonic motor also serves as the first spring charge drive source, and the second ultrasonic motor also serves as the second spring charge drive source. , And has a function of causing the second ultrasonic motor to start charging the shutter rear curtain at an appropriate time interval after the first ultrasonic motor starts charging the shutter front curtain. 6. The method according to claim 5, wherein
Shutter drive device. 8. The object driving device is configured as a shutter driving device for a camera, and the shutter driving device charges a spring for applying a driving force to the shutter curtain, and a restraining force is applied to the shutter curtain. An ultrasonic motor for adding and a control means for controlling the ultrasonic motor, wherein the control means charges the spring and charges the ultrasonic motor after the film feeding of the camera is completed. A shutter drive device having a function of charging a shutter curtain. 9. The object driving device is configured as a shutter driving device of a camera, and the shutter driving device comprises a first spring for applying a driving force to a shutter front curtain, and a first spring for charging the first spring. A first spring charge drive source, a first ultrasonic motor for applying a restraining force to the shutter front curtain, a second spring for applying a drive force to the shutter rear curtain, and a second spring for charging the second spring. A second spring charge drive source, a second ultrasonic motor for applying a restraining force to the shutter rear curtain, and the first and second spring charge drive sources and the first and second ultrasonic motors, respectively. And a control means for controlling, and the control means has a function of generating a signal for sending another film when the shutter rear curtain charge completion signal comes in first during the charging operation. To be Characteristic shutter drive device. 10. The object driving device is configured as a shutter driving device of an optical device, and the shutter driving device charges a first spring that gives a driving force to a shutter front curtain and the first spring. At the same time, a first ultrasonic motor for applying a restraining force to the shutter front curtain, a second spring for giving a driving force to the shutter rear curtain, and a second spring are charged, and a restraining force is applied to the shutter rear curtain. A second ultrasonic motor for adding, and a control means for controlling each of the first and second ultrasonic motors, wherein the control means has a constant power supply voltage of the optical device. When the voltage is equal to or more than the value, the first and second ultrasonic motors are simultaneously driven so as to charge the first and second springs at the same time. 1 spring charge Shutter driving device which is characterized by having a function of driving the ultrasonic motor of the second, as the charge of the second spring is performed after completion. 11. The control means has a function of changing the frequency of a standing wave generated in the ultrasonic motor according to the shutter time.
9, 10 shutter drive device. 12. The object drive device according to claim 1, wherein the spring is arranged on the outer circumference of the ultrasonic motor. 13. The shutter drive device according to claim 5, wherein the frequency of the standing wave generated in the ultrasonic motor is changed immediately before the completion of traveling of the shutter curtain. 14. The shutter drive device according to claim 5, wherein the frequency of the standing wave of the ultrasonic motor is gradually changed at the start of travel of the shutter curtain and immediately before the completion of travel. . 15. The shutter drive device according to claim 5, wherein a standing wave of the ultrasonic motor is stopped when the traveling of the shutter curtain is completed.