JP3419829B2 - Shutter mechanism - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shutter mechanism, and more particularly to a shutter mechanism having a shutter blade that also serves as a diaphragm blade.

[0002]

2. Description of the Related Art Conventionally, in a camera having a shutter blade that also serves as an aperture, when the shutter blade moves to an aperture open position, the shutter blade itself or a shutter blade drive member is stopped by contacting with a locking member. I am trying to let you. At this time, the shutter blade bounces and the opening waveform is disturbed, and the exposure amount is not stable, or underexposure is generated during flash photography. In order to solve these problems, as disclosed in JP-A-50-86344, there is known a technical means for providing a bound absorbing member on the back portion of the shutter blade or the like.

[0003]

However, in the above technical means, when the shutter blade is driven only by the spring biasing toward the open position, the biasing amount of the spring is extremely small. When an elastic member brakes the shutter blade itself to prevent the bounce, the amount of contact force with which the elastic member contacts the shutter blade needs to be small and stable. At this time,
If the braking force is too large, the shutter blades cannot move to the open position and stop halfway, resulting in underexposure. As described above, the conventional technical means cannot stabilize the above-mentioned ability.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a shutter mechanism capable of preventing the shutter blades from bouncing and providing accurate exposure.

[0005]

In order to achieve the above object, the first shutter mechanism according to the present invention retracts from the closed position where the photographing optical path is blocked to the outside of the optical axis to allow the passage of the photographing light. A shutter blade that also serves as an aperture blade and is movably driven to an allowed open position, and is disposed in front of or behind this shutter blade, near the plane portion and the end of the movement operation of the shutter blade to the open position. a braking member having an arm portion which tip portion is bent with respect to the planar portion so as to resiliently contact with the shutter blade, on the braking member
A regulating member for regulating the height from the serial flat portion to the previous end of the arm portion, characterized by including the. Further, in order to achieve the above-mentioned object, the second shutter mechanism according to the present invention is movably sandwiched between the blade pressing members and retracts from the closed position where the photographing optical path is blocked to the outside of the optical axis. The shutter blades that also serve as aperture blades are movably driven to an open position that allows the passage of photographing light, and the shutter blades that are arranged in front of or behind the shutter blades and move to the open position. A braking member having an elastic arm portion that has entered the shutter blade movement locus between the blade pressing members so as to elastically contact the shutter blade near the terminal end;
The elastic arm portion of the braking member provided on the blade pressing member
A restriction portion that abuts on the elastic arm portion to restrict the elastic arm portion to a fixed position ,
It is characterized by including.

[0006]

[0007]

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

FIG. 1 is a central sectional view showing the structure of a zoom lens barrel to which a shutter mechanism according to an embodiment of the present invention is applied, and FIGS. 2 to 5 show details of the zoom lens barrel. FIG. 3 is an exploded perspective view showing another configuration.

As shown in FIG. 1, the zoom lens barrel includes a first lens group 141, a second lens group 142, a third lens group 143, and a fourth lens group 144 arranged from the front. Hereinafter, each part will be described in detail with reference to FIGS. 1 and 2 to 5. 2 to 5 are exploded views of each member in the optical axis direction.

As shown in FIGS. 1 and 2, the fixed frame 52 of the lens barrel is fixed to the camera body (not shown) at the rear end,
A straight advance key groove 52a into which three straight advance keys 53b arranged at the rear end of the first lens group frame 53 (see FIG. 3) are fitted.
A straight keyway 52d into which the FPC guide 78 (see FIG. 5) is fitted is formed. A rotary frame 51 is rotatably fitted on the outer circumference of the fixed frame 52, and a groove 52c is formed on the outer circumference of the tip of the fixed frame 52 along the circumferential direction.
And a C ring 64 for locking the rotary frame 51 in the optical axis direction is attached.

On the other hand, on the inner periphery of the fixed frame 52, a middle frame 59
(See FIG. 5) The cam groove 5 that fits with the cam follower 59a.
2b is formed. Further, the inner circumference of the front end portion of the fixed frame 52 is made of a flocked cloth or the like for preventing unnecessary light from entering the mirror frame through the gap between the fixed frame 52 and the first lens group frame 53. The light blocking member 145 is fixed.

As described above, the rotary frame 51 is radially fitted to the outer periphery of the fixed frame 52 on the inner peripheral surface thereof, and is attached in the optical axis direction by the C ring 64 attached to the tip of the fixed frame 52. The movement is locked. This allows
The rotary frame 51 is movable in the rotational direction with respect to the fixed frame 52, but its movement in the optical axis direction is restricted.

Further, a bottomed cam groove 51b for moving the first lens group frame 53 in the optical axis direction and a bottomed bottom for moving the FPC guide 78 in the optical axis direction are provided on the inner circumference of the rotary frame 51. A cam groove 51c is formed, and the gear 5 is formed on the outer circumference.
1a is formed, and a zoom gear 227, which is an output gear of the zoom drive unit, meshes with the zoom gear 227 to perform rotational drive. Further, a pattern sheet 76 of a zoom encoder for the zoom photo reflector 139 for detecting the zooming position of the zoom lens is fixed to the outer periphery of the rotary frame 51.

As shown in FIG. 3, the first lens group 14 is used.
The first lens group frame 53, which is the first lens frame (mirror frame), is formed with straight-movement keys 53b which fit into the straight-movement key grooves 52a of the fixed frame 52 at equal intervals on the outer periphery of the rear end thereof. It is movable with respect to 52 in the optical axis direction. Further, a cam follower 53a that fits in the cam groove 51b of the rotary frame 51 is formed on the upper surface of the straight advance key 53b. Further, the shutter base plate 81 (see FIG. 4) is restricted in radial and rotational positions on the inner circumference of the first lens group frame 53, and the shutter lid 82 (see FIG. 4) is sandwiched therebetween. It is fastened with screws 65.

Further, a front frame 60 (see FIG. 4) and a middle frame 59 (see FIG. 5) are fitted to the inner circumference of the first lens group 53 so as to be freely rotatable in the circumferential direction, and the fourth lens group frame. 57 (see FIG. 5)
The roller 77 attached to the first lens group 53 enters the linear key groove 53e (FIG. 1) for restricting the fourth lens group frame 57 in the rotation direction.
(See) is formed at three locations on the inner circumference. In addition, a through hole 53c for press-fitting a pin 75 for regulating the inner frame 59 in the optical axis direction is formed.

Further, a barrier drive ring 69 for opening and closing a barrier is radially fitted to the front end portion of the first lens group frame 53 in the optical axis direction, and the barrier drive gear 100 (which protrudes from the hole of the front end portion) (See FIG. 4).

As shown in FIG. 5, the fourth lens group frame 57 is fastened with a screw so that the fourth lens group holding frame 56 holding the fourth lens group 144 is integrated, and the outer periphery thereof is provided. Three pins 57a are planted, and a roller 77 is rotatably fitted to these pins. The roller 77 is
The first lens group frame 53 is fitted in a straight-moving key groove 53e (see FIG. 1) provided on the inner circumference of the first lens group frame 53, whereby the fourth
The lens group frame 57 is movable only in the optical axis direction with respect to the first lens group frame 53, and is not movable in the rotation direction.

A fourth lens group spring 62 is provided between the fourth lens group frame 57 and the shutter base plate 81 (see FIG. 4).
Are arranged with the spring bearing 63 interposed therebetween, and the roller 7 is always
7 is urged so as to contact the end face cam 59b of the middle frame 59.

The outer periphery of the middle frame 59 and the inner periphery of the first lens group frame 53 (see FIG. 3) are fitted in the radial direction, and the first lens group is formed in a groove 59c formed on the outer periphery. When the tip end portion of the pin 75 press-fitted from the outer periphery of the frame 53 is fitted, the pin 75 is integrally advanced and retracted in the optical axis direction with respect to the first lens group frame 53, and is rotatably held. Also, the middle frame 59
A cam follower 59a that fits into the cam groove 52b of the fixed frame 52 is formed on the outer periphery of the. Also, the middle frame 59
An interlocking plate 66 is fixed to the outer periphery of the. Further, an end surface cam 59b is formed at one end of the middle frame 59.

As shown in FIG. 4, the front frame 60 is rotatably radially fitted to the inner circumference of the first lens group frame 53 at the outer circumference thereof, and has a plurality of second lens group frames 54 at the inner circumference. Straight key 5
A plurality of straight keyways 60b (see FIG. 1) into which 4a fits are formed, and a second lens group spring 61, which is a compression spring, is arranged between the second key group frame 54 and the second lens group frame 54. Further, on the outer periphery of the front frame 60, a gap 66a at the tip of the interlocking plate 66 is formed.
A protrusion 60a sandwiched between the two is formed, and is connected so as to rotate integrally with the rotation of the middle frame 59.

As a result, since the front frame 60 is radially fitted to the inner circumference of the first lens group frame 53, the interlocking plate 66 is provided.
As compared with directly rotating the second lens group frame 54, the eccentricity of the second lens group frame 54 with respect to the rotation can be suppressed to a minimum, and high optical performance can be maintained.

A barrier drive switching lever 101 for connecting the focus drive gear train 146 and the barrier drive gear train 147 is provided on the inner peripheral surface of the front frame 60, and is in a state other than the collapsed state. The position of the barrier drive switching lever 101 is regulated so that the connection is not performed, and the interlocking plate 66 causes the barrier drive switching lever 10 to be retracted when retracted.
There is provided a barrier drive switching lever position restricting cam portion that restricts the position of the barrier drive switching lever 101 so as not to hinder the connection of 1 to each other.

The second lens group frame 54 holds the second lens group 142, is formed with a plurality of straight-movement keys 54a which are fitted into the plurality of straight-movement key grooves 60b of the front frame 60, and is provided with a rear A cam follower 54b is formed at the end of the third lens group frame 55. The cam follower 54b contacts the end cam 55c formed on the inner peripheral surface of the third lens group frame 55. In addition, the second lens group frame 54
A second lens group spring 61 is sandwiched between the front end and the rear end of the front frame 60. Further, the straight-ahead key of the second lens group frame 54 is fitted in the key groove 60b of the front frame 60. As a result, the second lens group frame 54 and the front frame 60 rotate integrally in the rotation direction, but can freely move back and forth in the optical axis direction. The urging force of the second lens group spring 61 causes the cam follower 54b to move to the third lens group frame 55.
It works so as to contact the end surface cam 55c formed on the.

The third lens group frame 55 holds the third lens group 143, and has an inner peripheral surface on which an end face cam 55c having a displacement along the circumferential direction is formed on the end face in the optical axis direction. A cam follower 55d that abuts on the cam portion 58a of the focus cam ring 58 is formed.

The urging force of the second lens group spring 61 causes the cam follower 54b of the second lens group frame 54 to come into contact with the end face cam 55c of the third lens group frame 55, and the third lens group frame 54.
The cam follower 55d of the lens group frame 55 contacts the cam portion 58a of the focus cam ring 58.

As shown in FIG. 4, the third lens group frame 5
A protrusion having a hole 55a formed in the optical axis direction is formed on the outer peripheral surface of the optical disc 5, and a straight key 55b is formed on the outer peripheral surface at a position substantially opposite to the protrusion with respect to the optical axis. ing. A rod 89 held between the shutter base plate 81 and the shutter lid 82 of the shutter unit is fitted into the hole 55a, and the straight advance key 55b is fitted into a groove (not shown) formed on the shutter base plate 81. As a result, the third lens group 55 cannot rotate with respect to the shutter base plate 81 and can move only in the optical rotation direction.

The interlocking plate 66 is fixed to the outer peripheral portion of the middle frame 59, and the outer peripheral protrusion 60a of the front frame 60 is sandwiched in the gap 66a at the tip end thereof, whereby the middle frame 59 and the front frame 60 are integrated. It is connected to rotate with. Further, when moving from the short focus end to the retracted state, the barrier drive switching lever 101, which connects the focus drive gear train 146 and the barrier drive gear train 147 at the end face 66b thereof, is brought into the connected state.

As shown in FIG. 3, the barrier drive ring 69 has an inner diameter portion 6 at the tip portion 53f of the first lens group frame 53.
9e is fitted. Also, the internal gear 69a
Is connected to the barrier drive gear 100b by means of, and the periphery of the connecting portion is in a bag-like substantially sealed state. Two plate-shaped barrier springs 70 having a shape shown in the drawing are disposed on the surface opposite to the internal gear 69a (on the front side of the camera) so as to oppose each other, and urge the barrier blades 71 to act as barriers. The blade 71 and the barrier blade 73 are opened and closed.

The barrier spring 70 is a plate spring having a bent portion formed in the middle thereof, and is arranged on the circumference of the barrier drive ring 69. Both ends thereof come into contact with the protrusion of the barrier drive ring 69, and the protrusion 69d is inserted into the guide groove formed in the bent portion to regulate the movement in the optical axis direction and the rotation direction. It is arranged on the barrier drive ring 69 in a closed state.

As shown in FIG. 3, the barrier blade 71 has a boss 53 projecting from the tip of the first lens group frame 53.
Two arms having the same shape are arranged in the first lens group frame 53 so as to be rotatable around g. Then, the protruding portion 7 urged by the barrier spring 70.
1c, a protrusion 71a that drives the barrier blade 73 in the closed state, and a protrusion 7 of the barrier blade 73 in the opened state.
A recess 71b for urging 3b is formed.

The barrier blade 73 is the barrier blade 7
As in the case of 1, the arm is rotatable about the boss 53g at the tip of the first lens group frame 53, and the arm having the same shape is
One sheet is arranged in the first lens group frame 53. And
In the closed state, the protrusion 71a of the barrier blade 71 urges it, and in the open state, the protrusion 73b urges the barrier blade 71 to perform the opening / closing operation.

The cover ring 74 is attached to the tip of the first lens group frame 53 and regulates the positions of the barrier drive ring 69, the barrier blade 71, and the barrier blade 73 in the optical axis direction.

Further, as shown in FIG. 20, the FPC guide (flexible printed circuit board guide) 78 is engaged with the engaging portion 78b fitted into the straight-moving key 52d of the fixed frame 52 and the cam groove 51c of the rotary frame 51. Cam follower 78c
And a lens frame flexible substrate 302 disposed inside the lens frame.
And an arm portion 78a for pressing. Above arm 7
8a, the flexible frame printed circuit board 302 is assembled into a U-shape, and by the cam of the rotary frame 51,
The first lens group frame 53 is driven in the optical axis direction by a movement amount which is about half the moving amount, and further, the arm portion 78a restricts the operation guide of the lens frame flexible printed circuit board 302 and the spread in the optical axis direction. It has become.

FIG. 16 is a block diagram showing a main part configuration of a drive circuit in a zoom lens barrel to which the shutter mechanism of this embodiment is applied.

Inside the zoom lens barrel, a focus motor 108, a shutter plunger 111, a shutter trigger photo reflector 110, a focus photo interrupter 109, a zoom motor 201, a display device 307,
A release switch 318 and the like are provided, and these actuators, sensors and the like are connected to the control circuit 12 mounted on the main board in the camera body by the lens frame flexible printed board 302.

Returning to FIG. 1, two shutter blades 92A and 92B are arranged behind the shutter base plate 81. The shutter blades 92A and 92B are normally closed so as to block the light flux passing through the lens groups, and are opened for a predetermined time by a release operation and then closed. In addition, the shutter blades 92A, 9A
2B is a blade retainer 9 fixed to the shutter base plate 81.
The blade holders 93 and 94 are movably sandwiched between the blades 3 and 94, and serve to guide the shutter blades 92A and 92B when they are opened and closed.

The focus motor 108 is fixed to the shutter base plate 81, and the pinion gear 105 is fixed to the output shaft thereof. The rotation of the focus motor 108 is transmitted by the focus drive gear train 146 (see FIG. 4) to rotate the focus cam ring 58 to perform the focusing operation.

The sealing member 68 provided at the tip of the fixed frame 52 is a member for preventing water droplets from entering the inside of the camera and is made of an elastic material. Fixed frame 52 behind the camera
The outer peripheral side is fixed to the front cover 21. On the inner diameter side, the first lens group frame 53 is pressed,
The linear movement of the first lens group frame is possible, and the first lens group frame 5 is provided at two front and rear positions to prevent water droplets from entering the camera.
3 is provided with a lip portion 68a that is in line contact with the ring 3.

Next, details of the shutter mechanism according to the embodiment of the present invention will be described.

FIG. 6 is an exploded perspective view of an essential part showing the structure of the shutter mechanism of this embodiment, in which the optical axis direction is shown vertically in the drawing. 7 and 8 are explanatory views of the operation of the shutter mechanism, and FIG.
Shows respective states when the shutter is opened.

As shown in FIG. 6, behind the shutter base plate 81 (downward in the figure), a blade retainer 9 having a disk shape is formed.
3. A blade retainer 94 is fixedly provided on the shutter base plate 81. At the central portions of the blade retainer 93 and the blade retainer 94, openings 93b and 94 through which the photographing light flux passes, respectively.
b is formed, and a notch is formed in a part of the outer peripheral portion.

Two shutter blades 92A and 92B are arranged between the blade retainers 93 and 94. The shutter blade 92A and the shutter blade 92B
Is swingably attached to the shutter base plate 81 at swing centers 92a and 92b provided at the base ends thereof, and has a closed position for covering the openings of the blade retainer 93 and the blade retainer 94, and for exposure. It is designed to move between the open position where the photographing light flux passes. A long hole 92 is formed in the overlapping portion of the base ends of the shutter blades 92A and 92B.
c and 92d are bored so that a pin 90a of a shutter lever 90 described later can be inserted together with the notch.

On the circumference of the blade retainer 93, three slits 93a are formed at equal intervals. A blade retainer 95 having an outer circumference smaller than that of the blade retainer 93 is disposed on the upper surface of the blade retainer 93 in FIG. An elastic arm portion 95a is formed so as to extend outward from a position on the outer circumference of the blade retainer 95 that faces the slit 93a of the blade retainer 93. Further, the elastic arm portion 95a has a tip portion bent downward from the middle in the drawing, the tip portion is fitted into the slit 93a, and the tip thereof is the shutter blade 9.
It is capable of elastic contact with 2A and 92B.

The tip of the elastic arm portion 95a elastically abuts the shutter blades 92A, 92B near the final region of the opening stroke of the shutter blades 92A, 92B to brake the shutter blades 92A, 92B. Has become.

On the inner peripheral portion of the shutter base plate 81, approximately U
A shutter lever 90 having a character shape is pivotally supported by the shutter base plate 81 so as to be swingable about a cylindrical portion 90e extending upward in the drawing as a central axis. The pin 90a extending downward in the middle of one arm of the shutter lever 90 has the shutter blades 92A and 92A.
Long holes 92c and 92d formed in the overlapping portion of the base end portion of B
Is engaged with. Thereby, the shutter lever 90
Swings in the direction of the arrow in the figure, and the shutter blades 92A, 92
B is adapted to move between a closed position and an open position.

The arm portion of the shutter lever 90 further extends upward in the figure in the direction opposite to the pin 90a to form an arm portion 90d, and further, the arm portion 90d.
A cam follower 90b facing a cam portion of a locking arm 96, which will be described later, is formed at the tip of the.

A toggle spring 91 is provided around the base end portion of the shutter lever 90, that is, the columnar portion 90e so as to wind the winding portion thereof, and one end of the toggle spring 91 is provided at a predetermined position of the shutter base plate 81. In the provided locking portion 81a,
The other end is in contact with the arm portion 90d of the shutter lever 90. As a result, the shutter blades 92A,
92B is biased by the toggle spring 91 so as to be driven in the opening direction.

A plunger 111 having an iron core 112 is arranged near the other arm 90c of the shutter lever 90. The plunger 111 is fixed to the shutter base plate 81 so that the iron core 112 is attracted when power is supplied from a power source (not shown). The iron core 112 protruding from the plunger 111
The tip end portion is biased by a spring 113 in a protruding direction, and in a state where power is not supplied to the plunger 111, the tip end portion abuts against the other arm portion 90c of the shutter lever 90 and presses it. The shutter blades 92A and 92B are urged by a strong force in a direction to close them.

FIG. 9 is a side view showing the shutter lever and the locking arm and their peripheral portions in the shutter mechanism of this embodiment.

As shown in the figure, the locking arm 96 is provided on the shutter base plate 81 (see FIG. 6) so as to be swingably supported in the direction of arrow P in the figure. A winding portion of a toggle spring 97 is wound around the base end portion of the locking arm 96, one end of the toggle spring 97 abuts on the locking portion 81b, and the other end is a fan shape of the locking arm 96. Formed swing part 96d
On one side. As a result, the swinging portion 96
The cam follower 9 is biased upward in the figure and extends upward from the other side surface of the swinging portion 96d in the figure.
The tip of 6c is in contact with the cam portion 60B of the front frame 60. Since the cam portion 60B is displaced in the circumferential direction,
When the front frame 60 rotates in the direction of arrow Q in the figure, the locking arm 96 swings in the direction of arrow P.

FIG. 10 shows the locking arm 96 and the shutter lever 90 seen from the direction of arrow A in FIG.
Is shown.

A cam surface 96b is formed at the tip of the swinging portion 96d of the locking arm 96, and is formed at the tip of the arm portion 90d of the shutter lever 90 on the cam surface 96b when the shutter blade is opened. The cam follower 90b thus abutted is brought into contact with and stopped. That is, the cam surface 9
The opening diameter when the shutter blades are opened is regulated by 6b. When the shutter blades are closed, the shutter lever 90 is arranged apart from the cam surface 96b.

By the way, when the shutter blade is opened,
Due to the repulsive force of the shutter blades 92A and 92B and the repulsive force of the shutter lever 90 and the locking arm 96, the shutter blades 92A and 92B bounce and move in the closing direction.
It is considered that accurate exposure cannot be obtained. Therefore, in the shutter mechanism of this embodiment, the shutter blade 92
The elastic arms 95a of the blade retainer 95 are elastically brought into contact with A and 92B themselves near the end of the opening stroke to brake the shutter blades to prevent bounce.

Next, the aperture correction mechanism in the shutter mechanism of this embodiment will be described.

In this embodiment, the shutter lever 90 is brought into contact with the cam portion 96b of the locking arm 96 to determine the opening diameter when the shutter is opened. By the way, when the shutter lever 90 contacts the cam portion 96b, the front frame 6
The impact force is applied to the zero cam portion 60B. Therefore, when the cam portion 60B is formed as a part of the lens barrel or when the impact force is in the same direction as the moving direction of the cam, the cam is moved by the impact force, so that the impact force is applied to the lens barrel. And the lens barrel moves.

As a result, the image formed on the film surface moves and the sharpness of the image formed on the film disappears, resulting in a blurred photograph. Therefore, in the present embodiment, the impact force is applied by setting the direction in which the impact force is applied in the swinging axial direction of the engagement arm 96.
It does not become the swinging force of. Further, the reaction force of the impact force between the shutter lever 90 and the locking arm 96 is prevented from being directly transmitted to the lens barrel.

FIG. 11 is a plan view showing a main part of a shutter mechanism of a modified example of the above embodiment.

In the above embodiment, the cam portion 96b formed on the swinging portion 96d of the locking arm 96 is replaced by the shutter lever 9
Although the cam follower 90b formed in 0 is arranged substantially orthogonal to the swing locus, in the present modification, the shutter lever 90b is arranged.
The different point is that the swinging direction is substantially aligned with the direction of rotation of the member corresponding to the locking arm 96.

That is, the locking lever 9 in this modification
Reference numeral 6'denotes a lever having a central axis in a direction parallel to the optical axis, and plays the same role as the locking arm 96 in the above embodiment. A cam follower 96c ′ interlocking with the front frame 60 is formed on one arm portion, and an arcuate cam surface 96b ′ is formed on the other arm portion.
Of the cam follower 90b. The center of rotation (swing) of the locking lever 96 ′ is arranged on the extension line of the swing locus of the cam follower 90 b of the shutter lever 90.

According to this modification, the swinging direction and the impact force are directed toward the swinging center of the locking lever 96 ', but the effect is the same as that of the above-described embodiment.

Next, the shutter / bounce prevention mechanism of the shutter mechanism of this embodiment will be described.

In this embodiment, in order to prevent the shutter bouncing, the elastic blade portion 95a is brought into contact with the shutter blades 92A and 92B to brake the shutter blades.

By the way, as in this embodiment, the toggle spring 9
In the lens shutter type mechanism in which the relationship between the time in seconds and the aperture diameter is determined by 1, the force amount of the toggle spring 91 is very small. Therefore, the elastic arm portion 95a and the shutter blade 92A,
It is required that the force of contact with 92B is stable. If this force is large, the shutter blades 92A, 92B
If it is small, the bounce will increase.

FIG. 12 is a side sectional view showing the elastic arm portion 95a and its peripheral portion.

In order to stabilize the contact force amount between the elastic arm portion 95a and the shutter blades 92A and 92B described above, FIG.
As shown in, the plane portion of the blade presser 95 and the elastic arm portion 95a
The size of the difference (height) h from the tip is required to be stable. The elastic arm portion 95a and the shutter blades 92A, 9
It is desirable that the amount of force of contact with 2B is very small and the spring constant is small. Therefore, it is preferable that the longitudinal coefficient is small. However, such a material has poor workability and the height h of the elastic arm portion 95a is not stable. Further, for example, when the elastic arm portion 95a is manufactured by using a material such as PET (polyester film), the height h changes depending on temperature and humidity. That is, as shown in FIG. 13, a deviation of Δh occurs.

In the present embodiment, the above-mentioned slit 93a is provided in the blade retainer 93, and the elastic arm portion 95a is fitted into this slit 93a. As a result, the height h of the elastic arm portion 95a is determined by the two points of the end surfaces 93a 'and 93a "of the slit 93a, and the height h is stable. The bending point portion 95b is
It may be bent beforehand. However, the bending height at this time must be lower than h.

In the case of being bent, as shown in FIGS. 14 and 15, a ring-shaped member 359 may be interposed instead of the elastic arm portion 95a being inserted through the slit. . In this case, the height h is determined by the bending position 95b of the elastic arm portion 95a and the end surface 359a of the ring-shaped member 359.

Next, the zoom operation of the zoom lens barrel to which the shutter mechanism of this embodiment is applied will be described.

First, the zoom operation from the state of the lens frame short focus end shown in FIG. 1 to the long focus side will be described.

When drive power is supplied to the zoom motor 201 (see FIG. 16) arranged at a predetermined position of the camera body, the gear 227 (see FIG. 2) is driven to rotate the rotary frame 51. When the rotary frame 51 is rotated clockwise when viewed from the subject side, the cam follower 53a of the first lens group frame 53 fits into the cam groove 51b of the rotary frame 51, and the straight keyway 52a of the fixed frame 52 causes the rotary frame 51 to move in the rotational direction. Since the movement is restricted, the first lens group frame 53 goes straight to the left in the optical axis direction (toward the subject) in the figure.

At this time, the middle frame 59 is also the first lens group frame 53.
While moving to the left of the optical axis integrally with the fixed frame 52
The cam on the inner circumference rotates clockwise. The rotation of the middle frame 59 changes the position of the cam 59b of the middle frame 59, which contacts the roller 77 of the fourth lens group frame 57, whereby the relative position of the fourth lens group frame 57 with respect to the first lens group frame 53. Changes.

The interlocking plate 66 fixed on the outer periphery of the middle frame 59 rotates integrally with the middle frame 59, and accordingly, the front frame 60 is engaged with the front frame 60 by the straight advance key. The second lens group frame 54 also rotates by the same rotation angle as the middle frame 59. By this rotation, the second lens group frame 54
The contact position of the cam follower 54b with the end surface cam 55c of the third lens group frame 55 changes, and as a result, the relative distance between the second lens group 142 and the third lens group 143 changes.

By the rotation of the rotary frame 51, the FPC guide 78 also moves to the left of the optical axis by about half the amount of the first lens group frame 53, and the lens frame flexible substrate 302 attached to the shutter base plate 81 is mirrored. It suppresses trying to spread toward the center of the optical axis inside the frame.

In the above description, the driving from the short focus side to the long focus side in the zoom lens barrel to which the shutter mechanism of the present embodiment is applied has been explained, but the opposite drive from the long focus side to the short focus side is performed. Can be realized by rotating the rotary frame 51 counterclockwise.

Next, the focus drive mechanism in the zoom lens barrel to which the shutter mechanism of this embodiment is applied will be described.

When focusing is performed, drive power is supplied to the focus motor 108 from the camera body side.
As a result, the focus cam ring 58 rotates and the third
Rotation of the lens group frame 55 is restricted by the rod 89 and the rectilinear key 55b, and the lens group frame 55 is rectilinearly moved in the left direction of the optical axis. At this time, since the second lens group frame 54 is also engaged with the straight-movement key groove of the front frame 60, the second lens group frame 54 does not rotate but moves straight to the left in the optical axis by the same amount of movement as the third lens group frame 55. Moving.

As a result, the second lens group frame 54 and the third lens group frame 55 move integrally in the optical axis direction by the amount of focus adjustment, which is determined by the zoom operation and does not change the mutual interval. To do.

Next, the barrier opening / closing operation in the zoom lens barrel to which the shutter mechanism of this embodiment is applied will be described.

When shifting from the short focus state to the retracted state,
The interlocking plate 66 energizes the barrier drive switching lever 101 to bring the gear train of the focus drive unit and the gear train of the barrier drive unit into a connected state. When the focus drive unit is driven in this state, the barrier drive gear 100 rotates,
When the barrier drive ring 69 rotates, the barrier blade 71 and the barrier blade 73 of the barrier member open and close.

Next, the operation of the shutter mechanism of this embodiment will be described with reference to the flowchart shown in FIG.

First, the release SW 318 (see FIG. 16)
When is turned on, photometry is performed to determine the exposure (steps S1 and S2). As a result, the time of the second timer described later is set. Next, the plunger 11
When 1 is energized (step S3), the iron core 112 is attracted and the iron core 112 is retracted from the shutter closed position of the shutter lever 90. Thereby, the shutter lever 90
Is rotated by the urging force of the toggle spring 91, and the shutter blades 92A and 92B move toward the open position (FIG. 8).
reference). At this time, the first timer is started (step S4).

Thereafter, the tip portions of the shutter blades 92A and 92B cross the shutter photo reflector 110,
The shutter photo reflector 110 is turned on (step S5).

The second timer is started by the signal from the shutter photo reflector 110 (step S
9) Upon completion of counting by the second timer (step S10), the plunger 111 is turned off (step S11).

As a result, the iron core 112 of the plunger 111 is pushed out by the spring 113, and the tip portion b of the iron core 112 pushes the other arm portion 90c of the shutter lever 90 in the direction indicated by the arrow X in FIG. The shutter lever 90 swings in the closing direction of the shutter blades 92A and 92B, the shutter blades 92A and 92B are closed, and the exposure is completed.

In step S5, when the signal from the shutter photo reflector 110 is not detected for a certain period of time, it is determined that the shutter mechanism device is out of order and is displayed on the display device 307 (see FIG. 16) of the camera. The release SW 318 is locked (steps S6, S7, S8).

When the second timer is longer than the fixed time, the arm portion 90b of the shutter lever 90 is locked by the locking arm 96.
It comes into contact with the cam surface 96c and stops. The shutter opening waveform at this time has a trapezoidal shape as shown in FIG. When the shutter blades 92A and 92B bounce, the opening waveform becomes non-trapezoidal as shown in FIG. 19, but in the present embodiment, the shutter blades 92A and 92B are braked as described above. Since no bounce occurs, the opening waveform is
As shown in 8.

In this embodiment, the shutter blade 9
Although the above-mentioned blade retainer 95, that is, the elastic arm portion 95a is disposed in front of 2A, 92B, the same effect can be obtained even if the blade retainer 95 is disposed behind the shutter blades 92A, 92B. It goes without saying that you will play.

According to the shutter mechanism of this embodiment having such a structure, the height of the bent portion of the elastic arm portion 95a can be stabilized, so that the shutter blades 92A, 92A,
You can brake the 92B. Therefore,
Since the shutter blades are prevented from bouncing, accurate exposure can be obtained.

[0089]

As described above, according to the present invention, it is possible to provide a shutter mechanism that can prevent the shutter blade from bouncing and can obtain accurate exposure.

[Brief description of drawings]

FIG. 1 is a central cross-sectional view showing a state of a focus group initial position (infinity side) at a wide-angle end in a zoom lens barrel to which a shutter mechanism according to an embodiment of the present invention is applied.

FIG. 2 is an exploded perspective view of the zoom lens barrel of the embodiment.

FIG. 3 is an exploded perspective view of the zoom lens barrel of the embodiment.

FIG. 4 is an exploded perspective view of the zoom lens barrel of the embodiment.

FIG. 5 is an exploded perspective view of the zoom lens barrel of the embodiment.

FIG. 6 is an exploded perspective view of an essential part showing the configuration of the shutter mechanism of the above embodiment.

FIG. 7 is an explanatory diagram showing a state when the shutter is closed in the shutter mechanism of the above embodiment.

FIG. 8 is an explanatory diagram showing a state when the shutter is opened in the shutter mechanism of the above embodiment.

FIG. 9 is a side view showing a shutter lever and a locking arm and their peripheral portions in the shutter mechanism of the above embodiment.

10 is a side view showing the locking arm and the shutter lever viewed from the direction of arrow A in FIG.

FIG. 11 is a main part plan view showing a modified example of the shutter mechanism of the embodiment.

FIG. 12 is a side sectional view showing an elastic arm portion and its peripheral portion in the above-described embodiment.

FIG. 13 is an explanatory diagram showing a state when the height of the bent portion of the elastic arm portion in the above-described embodiment changes.

FIG. 14 is a perspective view of an essential part showing another modified example of the shutter mechanism of the embodiment.

FIG. 15 is a side sectional view of a main part showing another modified example of the shutter mechanism of the above embodiment.

FIG. 16 is a block diagram showing a main part configuration of a drive circuit in a zoom lens barrel to which the shutter mechanism of the above-described embodiment is applied.

FIG. 17 is a flowchart illustrating a shutter operation of the shutter mechanism of the above embodiment.

FIG. 18 is a diagram showing an opening waveform in the shutter mechanism of the above embodiment.

FIG. 19 is a diagram showing an example of one opening waveform in a conventional shutter mechanism.

FIG. 20 is a cross-sectional view of a lens frame flexible printed circuit board, an FPC guide and its peripheral portion in a wide, standard and tele states of a zoom lens barrel to which the shutter mechanism of the above-described embodiment is applied.

[Explanation of symbols]

51 ... Rotating frame 52 ... Fixed frame 53 ... First lens group frame 54 ... Second lens group frame 55 ... Third lens group frame 57 ... Fourth lens group frame 59 ... Middle frame 60 ... Front frame 61 ... Second lens group spring 60B ... Cam section 66 ... Interlocking plate 71, 73 ... Barrier blade 81 ... Shutter base plate 90 ... Shutter lever 90b ... Cam follower 92A, 92B ... Shutter blade 93, 94, 95 ... Feather presser 95a ... Elastic arm 96 ... Locking arm 96b ... cam surface 96c ... Cam follower 108 ... Focus motor 111 ... Plunger 112 ... Plunger iron core 113 ... biasing spring 141 ... First lens group 142 ... Second lens group 143 ... Third lens group 144 ... Fourth lens group

Claims (2)

(57) [Claims] 1. A shutter blade that doubles as a diaphragm blade and is movably driven from a closed position that shields a photographing optical path to an open position that retracts to the outside of an optical axis and permits the passage of photographing light. is disposed in front or behind the shutter blade, the plane
Parts and the upper so as to elastically contact with the shutter blade at the end near the movement in the opening position of the shutter blade
Includes a braking member which tip has an arm portion which is bent with respect to serial planar portion, and a regulating member for regulating the height of the previous end of the arm portion from the planar portion of the braking member, the A shutter mechanism characterized by the above. 2. A movably sandwiched member between the blade pressing members so that it can be moved from a closed position that shields the photographic optical path to an open position that retracts to the outside of the optical axis and permits the passage of photographic light. A shutter blade that also serves as a diaphragm blade, which is driven, is arranged in front of or behind the shutter blade, and is elastically contacted with the shutter blade near the end of the movement of the shutter blade to the open position. a braking member having a resilient arm that has entered the shutter blade movement in the trajectory between the vane holder, provided on the vane holder, the resilient arm portion of the braking member
A shutter mechanism, which is in contact with the shutter and restricts the elastic arm portion to a fixed position .