JPH04274418A - Mirror driving device - Google Patents

Abstract

PURPOSE:To offer an improved mirror driving device with a little vibration and noise by eliminating a trouble that the vibration and the noise are produced because a movable mirror is stopped by allowing a part of a mirror driving mechanism to collide with a rigid stopper, etc., when the mirror reaches a retreat position in a single lens reflex camera in which the mirror is allowed to pop up to the retreat position from a photographing optical path before photographing exposure. CONSTITUTION:By providing a cushioning member 34 on at least one of the mutual colliding surfaces of a 1st lever 11 and a 2nd lever 12 which collide with each other while the mirror is driven, the vibration and the noise are inhibited from being produced when both levers collide with each other, and the mirror driving device with a little vibration and noise is obtained.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mirror drive device for a single-lens reflex camera, and more particularly to an improved mirror drive device that generates less vibration and noise than conventional devices.

0002

[Prior Art] As is well known, a single-lens reflex camera has a built-in movable mirror that allows light to enter the finder optical system, and when taking pictures, the mirror is quickly retracted from the photographic optical path. A mirror drive device is provided for this purpose. Generally, a spring is used as a power source for rapidly retracting the mirror from the photographing optical path (mirror up), and a tensioning means ( There are many mirror drive devices that use the force of the spring to immediately retract the mirror from the photographing optical path by releasing the locking means (locking means), but when the mirror reaches the retracted position, a part of the mirror drive lever is Since the robot is brought to a stop by colliding with a stopper or the like, problems arise in that vibrations caused by the impact and noise generated by the collision occur.

[0003]Therefore, recently, there have been plans to develop mirror drive devices that generate less vibration and noise, and the applicant has already made several proposals for mirror drive devices that generate less vibration and noise than conventional devices. (for example, Japanese Patent Application No. 2-27723).

0004

[Problems to be Solved by the Invention] However, it cannot be said that the mirror drive device proposed by the present applicant has sufficient countermeasures against vibration generation and noise generation, and there are problems that should be further improved. There was a point.

An object of the present invention is to improve the mirror drive device of the prior application filed by the present applicant and to provide an improved mirror drive device that generates less vibration and noise.

[0006]

SUMMARY OF THE INVENTION The present invention is characterized in that a buffer member is provided at the mutually abutting portion of the two levers in the mirror driving device disclosed in the applicant's earlier application.

[0007]

[Operation] As shown in FIG. 1, by providing a buffer member 34 on at least one of the contact surfaces of the first lever 11 and the second lever 12 that contact each other during mirror drive, both levers are This suppresses the generation of vibration and noise during engagement, resulting in a mirror drive device with little vibration and no noise.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained in detail below based on embodiments shown in the drawings. FIG. 2 is a perspective view showing an embodiment of a camera having a mirror drive device of the present invention. FIG. 2 shows the mirror down state, where a photographing lens (not shown) is placed at the lower left side of the drawing, and the subject light reflected by the movable mirror is reflected upward in the drawing and guided to a finder optical system (not shown).

16 is a movable mirror, and a mirror box 50
A pivot shaft 16b is housed in the interior and protrudes from both sides of the proximal end.
is rotatably supported by the bearing portion of the mirror box 50, and is rotatable about the pivot 16b between the mirror down position shown in FIG. 3 and the mirror up position shown in FIG. 6.

A regulating plate (not shown) is fixed above the mirror box 50 and is fixed to its lower surface. The mirror-up position is determined by a buffer member 52 such as a molten plane, and the mirror-down position is determined by a stopper (not shown). Further, the movable mirror 16 has a drive pin 16a protruding through an elongated hole (not shown) formed in the side surface of the mirror box 50 for transmitting the driving force for raising and lowering the mirror. 16
The movable mirror 1 is moved by a second lever 12 (described later) that engages with a.
6 rotations are performed.

A gear and lever arranged on the right side of the mirror box 50 are used to raise and lower the movable mirror 16, and a buffer member 35, such as rubber, fixed to the mirror box 50 is used to move the movable mirror 16 up and down. This is to reduce the impact generated when the holder 16 is raised up, and details will be explained with reference to FIG. 1 and the drawings from FIG. 4 onwards.

Reference numeral 51 denotes a camera side mount fixed to the mirror box 50 with screws. The movable mirror 16 is shown in FIG.
), in the mirror-down state, the mirror-down position is formed by contacting the stopper 31;
A sub-mirror 25 for distance measurement, which is rotatably provided on the rear side of the mirror 25 via the pivot 16c, is rotated about the pivot 16c to a position where it abuts against the stopper 32, as shown. A central beam of object light on an optical axis 30a that enters the camera body through a photographing lens (not shown) is reflected by a movable mirror 16 and directed to an optical axis 30b toward the finder optical system, and a half mirror 16 provided on the movable mirror 16. The central light beam of the optical axis 30c that passes through the half mirror 16 is totally reflected by the total reflection mirror 27 of the sub-mirror 25 and guided to the distance measuring unit 28. Various proposals have been made regarding the configuration of the distance measuring unit 28, and since it is well known, a detailed explanation will be omitted.

Further, one end of a spring 29 supported by the pivot shaft 16c of the movable mirror 16 is hung on the drive pin 16a, and the other end of the spring 29 is hung on the spring hook part 25b of the sub-mirror 25. It is urged by a spring 29 in the mirror down direction. In the mirror-up direction, the cam surface 25a provided on the sub-mirror 25 and the dowel 33 for regulating the sub-mirror up position abut at the mirror-up position, and the sub-mirror 25 abuts against the back surface of the movable mirror 16 at the mirror-up position. I'm letting you do it.

Note that the cam surface 25 provided on the sub-mirror 25
The force with which the sub-mirror 25 abuts against the back surface of the mirror 16 can be adjusted by the relationship between the shape of a and the position of the dowel 33 for regulating the up position of the sub-mirror 25.

Conventionally, a toggle reversing mechanism as shown in FIG. 4(b) has been constructed at the location where such sub-mirror 25 is reversed, but the impact generated when the toggle is reversed generates noise. This mechanism can also eliminate that noise.

Note that a cam member (not shown) is required to operate the toggle reversing operation shown in FIG. 4(b), but since this mechanism is well known, illustration and explanation thereof will be omitted.

Further, the stopper 31 for regulating the mirror-down position of the sub-mirror 25 is constituted by a known adjustment mechanism such as an eccentric pin, so that the mirror-down position of the sub-mirror 25 can be finely adjusted.

A mirror drive mechanism for driving the movable mirror 16 constructed in this manner will be described below with reference to FIGS. 1 to 9.

Reference numeral 11 indicates a first lever, and reference numeral 12 indicates a second lever, each of which is formed in the shape shown in FIG. By rotatably fitting the shaft hole 11a of the first lever 11 into the shaft portion 12a formed around the shaft hole, the fitting length of both levers 11 and 12 can be adjusted. is made long so that the first lever 11 and the second lever 12 can swing while keeping the inclination due to backlash to a minimum. The second lever 12 is relatively swingable. Reference numeral 15 denotes a pulling spring, one end of which is hung on the spring hook 11d of the first lever 11, and the other end hooked on the spring hook 12b of the second lever 12, which causes the first lever 11 to move counterclockwise. In the direction of rotation, the second levers 12 are pulled toward each other clockwise.

The first lever 11 and the second lever 2 are arranged so that the contact portion 11e of the first lever 11 and the buffer member 34 fixed to the second lever 12 come into contact with each other due to the spring force of the pulling spring 15. are in contact and relative rotation is prevented. This buffer member 3
4 reduces the sound generated when the first lever 11 and the second lever 12 come into contact.

The contact portion 11e of the first lever 11 projects toward the second lever 12 located below, and the contact portion 11e of the buffer member 34 fixed to the fixed surface 12c of the second lever 12 34a is configured to have a height relationship with the corresponding abutting portion 11e, and allows contact or non-contact with both abutting portions 11e and 34a to be detected from the peephole 11f bored in the first lever 11. This will be used for the overcharge check described later.

[0022] Also, the first lever 11 and the first lever 1
The sound generated when the mirror drive cams 2 and 2 come into contact can be alleviated even in the state of the mirror drive cam 8. This is caused by a slight rotation of the helical gear 7 from the state of contact between the maximum lift portion 8a of the mirror drive cam 8 and the first cam contact portion 11c, which causes the maximum lift 8a of the cam to shift from the maximum lift portion 8a of the cam to the absorbing cam shape 8b. The movement of the first cam contact portion 11c absorbs overcharge, which will be described later, and alleviates the sound generated when the first lever 11 and the second lever 12 come into contact.

The second lever 12 has a first arm portion 12d and a second arm portion 12e formed at the rotating tip so as to sandwich the drive pin 16a of the movable mirror 16, and the mirror-down mechanism shown in FIG. In the position, the first arm portion 12d is the movable mirror 1
The second arm part contacts the drive pin 16a so as to prevent clockwise rotation of the second arm part 6, and rotates counterclockwise together with the first lever 11 when the mirror is raised. 12e rotates the movable mirror 16 clockwise from the mirror down position to the mirror up position while contacting the drive pin 16a. In addition, the movable mirror 16
When the second lever 12 rotates clockwise in the mirror-up position, the first arm 12d engages the drive pin 16a.
The movable mirror 16 is rotated counterclockwise while making contact with the movable mirror 16.

The counterclockwise rotational force of the second lever 12 for rotating the movable mirror 16 from the mirror down position to the mirror up position is generated by the spring hook 11b of the first lever 11 and the mirror box 50. The spring force is applied by the spring force of the mirror up spring 14 whose both ends are hung on the side spring hanging part 14a, and the mirror up spring 1 moves the movable mirror 16 from the mirror up position to the mirror down position.
A second lever 12 for rotating while charging 4.
Applying a clockwise rotational force to the mirror 16 and releasing the hold of the movable mirror 16 which is in a charged state at the mirror down position are performed by a motor-driven mirror drive cam 8 and a first lever that comes into contact with the cam 8, which will be described below. 11 cam contact part 1
This is done in relation to 1c.

1 is a motor, and 2 is a gear fixed to the output shaft of the motor 1. 3 is a transmission mechanism, which transmits the output of gear 2 to gear 4. The transmission mechanism 3 is configured by, for example, a reduction gear train, but since it can be easily configured by combining two-stage gears, its configuration will be omitted. In addition, in view of the space within the camera body, etc., in order to drive multiple mechanisms with one motor, it is also possible to have the transmission mechanism 3 serve as a mechanism that switches drive transmission in the forward and reverse directions of rotation of the motor. .

The gear 4 is fixed to the upper end of the transmission shaft 5 and transmits the rotation of the motor 1 to the transmission shaft 5. A worm gear 6 is fixed to the lower end of the transmission shaft 5, and this worm gear 6 is connected to the helical gear 7 having a rotating shaft in the mirror box described above.
are engaged, and when the motor 1 rotates in a predetermined direction, the helical gear 7 rotates only in the counterclockwise direction shown by the arrow.

A mirror drive cam 8 having the shape shown in the figure is fixed to the surface side of the helical gear 7, and the mirror drive cam 8 rotates in the same direction as the helical gear 7.

In the mirror down state shown in FIG. 3, the rotation of the motor 1 is stopped, and the first cam contact portion 11c of the first lever 11 is formed in the predetermined R shape of the mirror drive cam 8. The first lever 11 comes into contact with the maximum lift portion 8a, and is prevented from rotating counterclockwise by the biasing force of the mirror up spring 14. As mentioned above, the first lever 11 and the second lever 12 rotate integrally in a state in which they are pulled toward each other by the pulling spring 15 to a predetermined phase angle, but when the mirror drive cam 8 reaches the maximum A first cam contact portion 11c is provided on the lift portion 8a.
the first lever of the second lever 12 at a position slightly before it comes into contact with the
The arm portion 12d of the movable mirror 16 is brought into contact with the drive pin 16a so as to position the movable mirror 16 in the mirror down position, and the first lever 1 is moved until it reaches the maximum lift portion 8a.
The lever 1 rotates slightly clockwise against the spring force of the pull spring 15 while overcharging the mirror up spring 14, and the second lever 12 is applied with the spring force of the pull spring 15 and moves the movable mirror 16 into the mirror position. Press elastically into the down position. As described above, this overcharge state can be confirmed through the peephole 11f bored in the first lever 11, and the abutting portion 11e of both levers 11, 12,
If there is a predetermined gap between 34a and 34a, it is considered to be an effective overcharge state, and if they are in contact with each other or are not within the predetermined gap, the gap is adjusted to the predetermined gap.

On the other hand, this helical gear 7 meshes with a helical gear 9 for shutter charging, rotates the helical gear 9 clockwise, and charges the shutter in synchronization with the driving of the movable mirror 16. A shutter charge cam 10 is fixed to the helical gear 9. Reference numeral 17 denotes a shutter charge lever that can swing around a support shaft 17a, and a roller 18 provided at one end and rotatably supported by the support shaft 17b comes into contact with the cam surface of the shutter charge cam 10, and the other end The charge lever is in contact with a charge lever that is supported by a support shaft 17c provided in the charge lever. The shutter charge lever 17 charges a shutter (not shown) by rotating in a counterclockwise direction, and FIG. 3 shows the shutter in a fully charged state.

Further, a position detection mechanism for detecting the position of the mirror drive cam 8 is provided coaxially with the helical gear 7 on its back side, and this mechanism is connected to the contact piece 20 fixed to the helical gear 7.
and detection patterns 22, 23, 24 with which the contact piece 20 contacts.
A substrate 21 having a surface thereof.

FIG. 5 is an enlarged plan view of the substrate 21, and the detection pattern 22 is supplied with a GND potential through the input section 22c, and is supplied to the signal pattern section 22a via the connection section 22b. The detection pattern 23 includes a signal pattern section 23a and a connection section 2.
3b and an output section 23c, the detection pattern 24
is composed of signal pattern sections 24a and 24b, a connection section 24c, and an output section 24d. The contact piece 20 in the mirror down position has signal pattern portions 22a arranged in three concentric rows on the line indicated by the contact line 20a.
, 23a, 24a, and determines whether the GND potential supplied from the detection pattern 22 is transmitted to the detection patterns 23, 24. In the following description, the signals of the detection patterns 23 and 24 are assumed to be at L level when they are in contact with the detection pattern 22, and at H level when they are in a non-contact state. Therefore, in the case shown in FIG. 5 (corresponding to FIG. 3) in which the signal pattern portions 22a, 23a, and 24a are in a conductive state, the detection pattern 23 is L, and the detection pattern 24 is L, the movable mirror 16 is mirror-down. The location will be detected.

The first lever 11 moves the maximum lift portion 8 of the mirror drive cam 8 in the mirror down position shown in FIG.
The rotation in the counterclockwise direction is prevented by the contact between a and the first cam contact portion 11c, and from this state, the helical gear 7 starts rotating, and with a slight amount of rotation, the first lever 11 is rotated. The first cam contact portion 11c is no longer in contact with the mirror drive cam 8, that is, the movable mirror 16 is released from tension, and the first lever 11 is free to rotate, so it is not in the charging state. The first lever 11 is rotated counterclockwise by the spring force of a certain mirror up spring 14. At this time, the first lever 11 and the second lever 12 are pulled together by the pulling spring 14 so that the abutting portions 11e and 34a are in contact with each other, so that they rotate together in the counterclockwise direction. Therefore, the second arm portion 12e of the second lever 12 comes into contact with the drive pin 16a of the movable mirror 16,
The movable mirror 16 is rotated clockwise from the mirror down position to the mirror up position. Second arm 12
The abutting surface with the drive pin 16a of e is shown in FIG.
D) and as shown in FIG. 6, the first cam surface 12f and the second
When the second lever 12 starts rotating counterclockwise from the mirror down state, the first cam surface 12f first comes into contact with the drive pin 16a, and the movable mirror 16 in the clockwise direction. When the mirror rotates further and reaches the point where mirror up is completed, drive pin 1
6a shifts from the first cam surface 12f to the second cam surface 12g. Then, just before the movable mirror 16 reaches the mirror-up position, the contact surface 16d of the movable mirror 16
is a mirror box 50 and a movable mirror 1 as shown in FIG. 7(b).
6 (near the pivot 16b)
The movable mirror 16 comes into contact with the buffer member 35 fixed to the surface 50a of the movable mirror 16, and a part of the rapid kinetic energy generated when the movable mirror 16 moves from the mirror-down position to the mirror-up position is attenuated here. After that, as shown in FIG. 7(C), the movable mirror 16
When the mirror reaches the mirror up position against the buffer member 35, it comes into contact with a buffer member 52 such as a malt plane provided above the mirror box 50, where the entire kinetic energy of the movable mirror 16 is absorbed and the mirror is raised. It will be completed.

That is, as shown in FIGS. 7(a) to 7(c), the movable mirror 16 first receives a buffering effect from the buffer member 35 immediately before reaching the mirror-up position, and then receives the buffering action from the buffer member 52.
By coming into contact with the movable mirror 16, the sudden kinetic energy of the movable mirror 16 is absorbed and stopped.

Conventionally, only the buffer member 52 was used.
Buffering has been performed when the mirror is raised, but with this method, the deceleration angle is only about θ1 as shown in FIG. 8(b), so sufficient buffering cannot be obtained.

On the other hand, the buffer member 35
It is fixed near the pivot shaft 16b of No. 6, and it is possible to obtain a larger mirror-up force due to the ratio of the lever to the mirror-up force at the mirror tip, so it is possible to use a buffer member with a larger buffering force. The angle that reduces the kinetic energy when the mirror is raised is θ in Figure 8(c).
It can be made larger as shown in 2. Note that (a) in FIG. 8 shows a state in which mirror-up has been completed.

Also, regarding the material of the buffer member, it is preferable to use a soft material rather than a hard material, and desirable results can be obtained by increasing the deceleration angle and using a soft buffer member.

In the mirror-up state, the second cam surface 12g has an angle that increases the holding force of the movable mirror 16 in the mirror-up state, and the biasing force of the mirror-up spring 14 causes the buffer member 35, The movable mirror 16 rotated to the position against the rotation angle 52 is prevented from bouncing when the mirror is raised, and the mirror-up position is guaranteed. Thereby, the movable mirror 16 can be stabilized in the mirror-up state reliably and quietly in a short time. In this mirror-up state, the sub-mirror 25 also rotates clockwise by the mechanism described above, as shown in FIG.
As shown in (a), a dowel 33 for regulating the up position of the sub-mirror 25 and a cam surface 25a provided on the sub-mirror
As a result, the sub-mirror contacts the back surface of the movable mirror 16, but at this time, immediately before the sub-mirror contacts the back surface of the movable mirror 16, the sub-mirror contacts a buffer member 36 provided between the sub-mirror 25 and the movable mirror 16 as shown in FIG. , here, the kinetic energy when the sub-mirror 25 comes into contact with the movable mirror 16 is partially reduced. After that, the submirror 25 is
The dowel 33 and the cam surface 25a provided on the sub-mirror 25 abut against the back surface of the movable mirror 16.

[0038] Also, this buffer member 36
It can also be used to prevent reverse light from entering the finder between the mirror 6 and the sub-mirror 25. Further, by forming the sub-mirror 25c in the shape shown in FIG. 12, it can be used to prevent reverse light from entering the finder.

Even after the above-mentioned holding of the movable mirror 16 is released,
The motor 1 is rotating, and the helical gear 7 is rotating in a predetermined direction, but it is temporarily stopped in the state shown in FIG. 6 when the mirror up is completed.

Furthermore, during shutter charging, the shutter charge lever 17 rotates in the clockwise direction because its roller 18 is out of the maximum lift portion of the shutter charge cam 10, while the roller 19 rotates clockwise. The charge holding state of the charge lever has been released. In this state, a shutter (not shown) can perform an exposure operation.

[0041] Furthermore, the mirror drive cam position detection mechanism is as follows:
In the mirror-up stopped state, there is a signal detection state shown in FIG. 13.

The contact piece 20 is in contact with only the signal pattern portion 22a on the contact line 20a, and therefore both the detection patterns 23 and 24 are at H level.

FIG. 14 is a diagram showing a mirror down completion state during the shutter charging operation.

At the beginning of the mirror down operation,
The second cam contact part 11g of the first lever 11 contacts the cam part 8b of the mirror drive cam 8, and the first lever 11 rotates clockwise, and the second lever 12 also rotates in the clockwise direction. The second lever 12 rotates clockwise together with the lever 11, and the first arm 12d of the second lever 12 contacts the drive pin 16a of the movable mirror 16, thereby rotating the movable mirror 16 counterclockwise. When the motor 1 further rotates, the first cam contact part 11c of the first lever 11 contacts the cam part 8c of the mirror drive cam 8, and immediately before the movable mirror 16 contacts the stopper 31, the first cam contact part 11c of the first lever 11 contacts the cam part 8c of the mirror drive cam 8. The shape of the cam portion 8c is changed to the movable mirror 16.
Cam state 8 in which the cam remains in non-contact with the stopper 31
d, and then rotate counterclockwise to the mirror down position. This alleviates the kinetic energy from the mirror up position to the mirror down position, thereby alleviating the sound generated when the movable mirror 16 contacts the stopper 31.

FIG. 14 shows this state, in which the first cam contact portion 11c of the first lever 11 is connected to the mirror drive cam 8.
The motor 1 further rotates and rotates the first lever 11 in the clockwise direction, resulting in the above-mentioned overcharge state, and the first lever 11 is not in contact with the maximum lift portion 8a. The cam contact portion 11c comes into contact with the maximum lift portion 8a of the mirror drive cam 8 as shown in FIG. 3, and the motor 1
rotation stops. Note that the first cam contact portion 11c of the first lever 11 is at the maximum lift portion 8a of the mirror drive cam 8.
The energization state of the motor 1 before it comes into contact with the motor 1 will be described later.

Furthermore, in the past, when the movable mirror 16 was rotated to the mirror down position, it was thought that it would hit the stopper 31 and bounce, but since the kinetic energy is relaxed just before the mirror down position. , almost no bounce occurs.

Furthermore, since the first lever 11 is rotated to the overcharge position against the spring force of the pull spring 15, the second lever 12 engaged with the drive pin 16a of the movable mirror 16 This spring force suppresses the bounce and the mirror comes to rest in the mirror down position in a short period of time.

On the other hand, in the shutter charge system, the shutter charge cam 10 and the roller 18 have started to come into contact with each other, and the shutter charge lever 17 has started rotating counterclockwise. Basically, the mirror down operation is performed first and then the shutter is charged.
The reason for the overlap of the drive loads in 4 is to set the load to be approximately constant within a range where the maximum load does not increase.

FIG. 15 shows the signal detection state of the position detection mechanism of the mirror drive cam 8 when the mirror down is completed in FIG. On the contact line 20a of the contact piece 20,
The signal pattern parts 22a and 24b are in contact, the detection pattern 23 is at H level, the detection pattern 24 is at L level,
It is.

FIG. 16 is a chart showing the signal detection states of the detection pattern 23 and the detection pattern 24 in each process during one rotation of the mirror drive cam 8.

In the charge completion stop state shown in FIGS. 3 and 5, both the detection patterns 23 and 24 are at the L level, as described above. Here, in a phase in which energization of the motor 1 is started and the first cam contact portion 11c of the first lever 11 is released from the maximum lift portion 8a of the mirror drive cam 8, the detection pattern 23 changes from the L level. Switches to H level. In this phase, the movable mirror 16 starts to rise due to the mirror up spring 14, and after a predetermined time it becomes stable at the mirror up position. In other words, detection pattern 2
By setting a predetermined timer from the state in which the signal 3 switches from the L level to the H level, it is possible to know the mirror-up stabilization timing regardless of the power supply state.

In parallel with this, the motor 1 continues to be energized, and when the roller 18 of the shutter charge system is released from the regulation by the shutter charge cam 10, the detection pattern 2 is detected.
4 switches from L level to H level. At this point, the motor 1 is stopped in the state shown in FIG. 6 by applying a brake.

When the exposure operation is completed and the motor 1 starts to be energized to reach the state shown in FIG. 7, the signal of the detection pattern 24 switches from the H level to the L level. This signal causes
Regardless of the power state, the movable mirror 16 and submirror 25
You can know exactly when the mirror has reached the mirror down position. Based on this timing, by providing a predetermined timer, it is possible to accurately know the timing at which the movable mirror 16 and the sub-mirror 25 become stable. The detection pattern 24 switches from L level to H level while the motor 1 is energized, but the motor 1 continues to be energized. When the roller 18 reaches the maximum lift range of the shutter charge cam 10, the signal pattern section 23a switches the detection pattern 23 from the H level to the L level, and when the roller 18 further rotates by a predetermined angle, the signal pattern section 24a switches the detection pattern 24 to the H level.
Switches from level to L level. This signal change is shown in Figure 2.
In order to stop the mirror drive cam 8 in this state, the power to the motor 1 is stopped, the terminals are shorted, and the brake is applied in two ways: early or late. It's for a reason.

That is, when the power supply voltage is high, the rotation speed of the motor 1 is high and the amount of overrun of the mirror drive cam 8 after applying the brake is also large, so that the signal pattern 23 changes from the H level to the L level. The brake is applied at an early change, and the predetermined position mirror drive cam 8 shown in FIG.
to stop.

On the other hand, when the power supply voltage is low, the rotational speed of the motor 1 is low and the amount of overrun of the mirror drive cam 8 after applying the brake is also small, so that the signal pattern 24 is H.
The brake is applied at a late change from the level to the L level, and the mirror drive cam 8 is stopped at a predetermined position shown in FIG.

In this embodiment, the brake timing is switched only at two points in time, but it goes without saying that the larger the number of divisions, the more accurate the stop phase will be. Therefore, even if the power supply voltage changes, the time from the start of energization to the motor 1 until the start of the mirror-up operation can be kept shorter and more stable.

As described above, this embodiment realizes shortening and stabilization of the release time lag, and also achieves the reduction and stabilization of the release time lag.
This configuration is also effective for continuous frame-up continuous shooting using the flying release system as disclosed in No. 631, since the mirror-up stabilization timing can be accurately determined.

FIG. 17 is a block diagram showing one embodiment of the control circuit of this embodiment. Reference numeral 100 denotes a photometry switch that is turned on at the first stroke of a release button (not shown), and 101 is a release switch that is turned on at the second stroke of the release button. Signals from these switches 100 and 101 are input to a microprocessor (MPU) 102. be done. This M
The PU 102 includes a shutter travel completion signal 103 from a means for detecting the completion of travel of the rear curtain of the shutter (not shown), and the aforementioned detection patterns 23 and 2 for controlling the energization of the motor 1.
4 and a film advance signal 104 from a film advance detection means (not shown) are also input. Regarding the photometry circuit 105 and the distance measurement circuit 106, information on operation timing is sent from the MPU 102, and their respective outputs are transferred to the MPU 102. Motor 1 and film feed. It is driven by signals from the MPU 102 via motor drivers 108 and 109. These motor drivers 108 and 109 drive the motor 1 and the film feeding motor 107 in forward and reverse directions.
It has a bridge circuit that can be switched to an electric brake state forming a short circuit. When operating a shutter (not shown), the front curtain (not shown) is started by energizing the shutter front curtain magnet 110 in response to a signal from the MPU 102, and after a predetermined shutter time, the rear shutter curtain is started by a signal from the MPU 102. As for the interface with the photographing lens camera body (not shown), there is no mechanical connection, but only electrical communication between the MPU 102 on the camera body side and the lens control circuit 112. However, the power for driving the photographic lens side is supplied from the camera body side.

The photographic lens has its own aperture drive actuator 113 and focus drive actuator 114, and is driven via the lens control circuit 112 by commanding drive timing from the MPU 102.

The control circuit configured as described above operates according to the time chart shown in FIG.

This time chart shows a state in which the photometry switch 100 of the first stroke of the release button (not shown) is in the on state, and the second stroke is switched on and connected as it is. Further, the feeding mode can be switched between continuous shooting mode and single shooting mode by a mode setting means (not shown), and this time chart shows a state in which continuous shooting mode is set. In the battery check, an actual load check is performed with the front curtain magnet 110 and the rear curtain magnet 111 of the shutter being energized. Regarding the movable mirror 16, the state change of up and down is shown. Further, this time chart shows a state in which autofocus is performed and continuous shooting is performed while predicting the movement of a moving subject (moving object).

The operation of the camera of this embodiment will be explained below based on the flowchart shown in FIG. 19 while referring to the timing chart of FIG.

[0063] In step (hereinafter abbreviated as S)-1,
When the photometry switch 100 is turned on (S-2) with a power switch (not shown) turned on, a wake-up operation (S-3) is performed, and a DC/DC converter (not shown) is operated to open various circuits. is in the operating state.

Next, the photometry circuit 105 and the distance measurement circuit 106
Based on the information, the focus drive actuator 114 of the photographing lens is operated to start focus drive (S-5). The details of distance measurement and lens focus driving are as shown in Japanese Patent Laid-Open No. 1-107224, in which the lens focus is driven by predicting the movement of the torso, and the explanation thereof will be omitted.

In S-6, release switch 101
If not turned on, after a predetermined amount of lens focus driving is completed (S-7), the process returns to S-4 to perform photometry and distance measurement operations. If the release switch 101 is turned on during this time, the lens focus drive is stopped (S-8).
, enters the shooting sequence.

In this embodiment, the release switch 1
In order to emphasize the release time lag after 01 is turned on, the lens focus drive is stopped midway, but the lens may be driven by a predetermined amount before proceeding to the photographing sequence. Further, depending on the state of distance measurement, proceeding to photographing may be prohibited.

A battery check is performed at S-9, and if the voltage is higher than the predetermined voltage, the BCH and flag are set (S-9).
-10), BCL if lower than the predetermined voltage. A flag is set (S-11).

At S-12, energization of the motor 1 is started. At the same time, a release time lag stabilization 70 ms timer is started to keep the release time lag constant (S-13). This timer is set based on the maximum time required to drive the lens aperture, which varies depending on the aperture value, and is also set so that the movable mirror 16 also completes raising during this time. As a result, the release time lag when performing the above-mentioned moving object prediction autofocus is kept constant, so prediction accuracy is improved.

Then, in order to avoid a rush current when starting the motor 1, lens narrowing is started (S-15) after a delay of 15 ms (S-14).

In S-16, when the signal pattern 23 for detecting the phase of the mirror drive cam 8 becomes H level,
A 35 ms mirror-up guarantee timer is started (S-17). The switching of the signal pattern 23 to the H level is the phase at which the movable mirror 16 starts rising.

[0071] Continuing to energize motor 1, detection pattern 2
When signal 4 switches to H level, power to motor 1 is stopped (S-18) and the electric brake is applied (S-18).
19).

[0072] When the lens narrowing is completed (S-20
), when the conditions of 35ms for the mirror up guarantee timer and 70ms for the release time lag stabilization timer are satisfied (S-21, 22), the shutter leading curtain magnet 1
10 (S-23), and after a predetermined shutter time (S-24), the shutter rear curtain megnet 111 is energized (S-25) to run the front and rear curtains of the shutter. Perform exposure operation.

At S-26, when the shutter run completion signal is input, energization of the motor 1 is started (S-2
7). Then, after a delay of 15 ms (S-28), the opening operation of the lens aperture is started (S-29).

At S-30, when the opening operation of the lens aperture is completed, the film feed motor 107 is energized to start film winding (S-31).

At S-32, when the signal of the detection pattern 24 switches to L level, a mirror down position stability timer of 40 ms is started (S-33). This is a timer to ensure that minute vibrations are stabilized after the movable mirror 16 and sub-mirror 25 reach the down position.

Here, if it is continuous shooting mode (S-34)
, starts distance measurement and photometry operations (S-35). If the mode is single shooting mode, the process advances to S-36.

[0077] In S-36, the detection pattern 36 is
When the level changes, the B memorized in S-10 and 11
If the C flag is at the H level, the electric brake is immediately applied to the motor 1 (S-39), and if the BC flag is at the L level, the detection pattern 24 is at the L level. Wait for the switch to the level (S-38), and apply the electric brake to motor 1 (S-38).
-39).

At S-40, when the completion of film winding is detected by the film winding signal, the supply of electricity to the film feeding motor 107 is stopped and an electric brake is applied (S-41).

In S-42, if continuous shooting mode is selected, S-42
-2, and release switch 101 at S-43.
If it is on, the process advances to S-44, and if it is off, it returns to S-2.

If distance measurement and photometry have been completed in S-44, lens focus driving is started (S-45). Then, after waiting 15 ms (S-46), energization to the motor 1 is started (S-47), and a release time lag stabilization timer of 70 ms is started (S-48).

Next, after waiting 15 ms (S-49), the lens narrowing down operation is started (S-50).

At S51, when the signal of the detection pattern 23 switches to H level, a mirror up guarantee timer of 35 ms is started (S-52). and,
When the signal of the detection pattern 24 switches to H level (S-
53), the power supply to the motor 1 is stopped and the brake is applied (S-54).

In S-55, the aperture of the lens is completed, in S-56 the lens focus drive is completed, in S-57 the mirror up guarantee timer 35ms has elapsed, and in S-58 the release time lag stability timer 7 is activated.
When the elapse of 0 ms is detected, the process returns to S-23, where the shutter front curtain magnet 110 is energized, and a series of operations proceed based on the flow described above. Also,
If the release switch 101 remains on in the continuous shooting mode, repeated shooting continues based on the above-described flow.

[0084]

As explained above, in the mirror driving device of the present invention, since the buffer member 34 is provided at the mutually abutting portion of the first lever 11 and the second lever 12, when both levers abut, The generation of noise and vibration is reduced, and the drawbacks of conventional devices can be eliminated.

[Brief explanation of the drawing]

FIG. 1 is a plan view and a side view of a first lever 11 and a second lever 12, to which the present invention is applied, among the components of a mirror driving device according to the present invention.

FIG. 2 is a perspective view of essential parts of a single-lens reflex camera equipped with a mirror drive device of the present invention.

FIG. 3 is a side view of essential parts of the mirror driving device of the present invention.

FIG. 4 is a diagram showing two states of the movable mirror 16 and the submirror 25.

FIG. 5 is a front view of a printed circuit board as a means for detecting the position of the movable mirror 16, and is a diagram showing the mirror down state detection state.

FIG. 6 is a side view of the mirror drive device when the mirror is in the exposed and retracted position.

FIG. 7 is a layout diagram of a mirror shock absorber.

FIG. 8 is an explanatory diagram of the deceleration angle when the mirror is raised.

FIG. 9 is a diagram showing another embodiment of the mirror shock absorber.

FIG. 10 is a diagram showing another embodiment of the mirror shock absorber.

FIG. 11 is a diagram showing an example of a submirror buffer device.

FIG. 12 is a diagram showing another embodiment of the submirror buffer device.

FIG. 13 is a diagram showing a detection state at the movable mirror up position.

FIG. 14 is a diagram showing the mirror down state of the movable mirror.

FIG. 15 is a diagram showing a detection state of a mirror down state.

FIG. 16 is a table showing signal detection states during camera operation.

FIG. 17 is a block diagram of a control circuit of the camera of FIG. 2;

FIG. 18 is a time chart of the driving sequence of the camera.

FIG. 19 is a flowchart showing control operations in the camera.

[Explanation of symbols]

1...Motor 2...
Gear 3…Transmission mechanism 4
…Gear 5…Transmission shaft
6... Worm gear 7... Helical gear
8...Mirror drive cam 9...Hasbar gear
10...Shutter charge cam 11, 12...Lever 13...Spindle 1
4...Mirror up spring 15...Attraction spring 16...Movable mirror 20...Touch pieces 22, 23, 24...Detection pattern 25...Sub mirror 29...Sub mirror biasing spring 33...Mirror up dowel 34...Lever buffer member 35...Mirror up buffer member 36...Submirror buffer member

Claims (1)

[Claims] Claim: A spring member that applies rotational force from the finder observation position to the exposure retraction position to a movable mirror that is rotatable between the viewfinder observation position and the exposure retraction position; a mirror charge actuating means for rotating the mirror from an exposure retreat position to a finder observation position against the spring force of the spring member; and a mirror charge actuating means that rotates in a predetermined direction while in contact with the mirror charge actuating means. A cam member having a cam surface that applies rotational force for charging the movable mirror to the means and maintains the mirror charged state at the maximum lift position, and a motor that drives the cam member, In the mirror drive device configured such that the movable mirror starts rotating to the exposure retreat position at a predetermined phase of the cam member, the mirror charge actuating means includes a first lever that comes into contact with the cam member; , a second lever that is rotatable about the same axis as the first lever and that engages the first lever and the movable mirror;
a spring biasing the first lever and the second lever toward each other; and a relaxation member provided on at least one of the levers to reduce the impact when the first lever and the second lever are engaged. A mirror drive device comprising: