JP4589816B2 - Lens barrel drive mechanism - Google Patents

Description

  The present invention relates to a lens barrel drive mechanism, and more particularly to a lens barrel drive mechanism used in an optical system apparatus.

2. Description of the Related Art Conventionally, a lens barrel driving mechanism used for zooming and focusing while driving two front and rear lens groups in the front-rear direction is known.
In such a lens barrel driving mechanism, various techniques for reducing the dimension in the optical axis direction when not photographing are proposed, and an opening of the shutter is opened when not photographing, and a lens adjacent to the shutter in the opening. A technique for storing at least a part of the optical system and a technique for storing a part of the optical system in a state in which a part of the optical system is retracted from the optical path are known. In the latter technique, a method is used in which the lens is swung in a plane perpendicular to the optical axis and retracted out of the optical axis (see, for example, Patent Documents 1 and 2).
JP 2004-317943 A JP 2004-318051 A

However, when the lens is retracted as described in Patent Documents 1 and 2, the lens is simply slid in a plane perpendicular to the optical axis direction. As a result, the length of the optical system in the radial direction is increased, and as a result, the entire camera cannot be reduced in size.
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a lens barrel drive mechanism that can be reliably reduced in size.

In order to solve the above problems, the invention of claim 1 is a front lens frame (second lens frame 3) that holds a front lens group (second lens group 31) as shown in FIGS. When,
A rear lens frame (third lens frame 4) for holding a rear lens group (third lens group 41);
A holding portion (holding frame 100) that is disposed on the rear side of the rear lens frame and holds the rear lens frame;
A protrusion 103 disposed on the further rear side of the holding portion and in contact with the rear lens frame in accordance with the retraction operation;
The rear lens frame extends rearward from the periphery of the rear lens group, and is provided on the holding portion so as to be rotatable around a rotation shaft 102 that intersects the optical axis direction. Have
The arm portion is rotated by being brought into contact with the protruding portion in accordance with the retraction operation, rotates around the rotation axis, and the lens surface of the lens group in the optical path is in the optical axis direction. And swinging from a photographing state arranged so as to be substantially orthogonal to an accommodation state where the lens surface of the lens group is arranged substantially parallel to the optical axis direction outside the optical path.

  According to the first aspect of the present invention, as the arm portion comes into contact with the protruding portion in accordance with the retraction operation, a rotational force is applied to rotate around the rotation axis. Then, from the shooting state in which the lens surface of the lens unit is disposed so as to be substantially orthogonal to the optical axis direction in the optical path, the lens surface is disposed substantially parallel to the optical axis direction outside the optical path. Swing to the stowed state. In the retracted state, the lens surfaces of the lens units are arranged so as to be substantially parallel to each other. Unlike the conventional case, the lens surface is simply slid up and down so that the lens surface is substantially perpendicular to the optical axis direction. Since the entire length is shortened by the length of the lens group in the radial direction, the lens barrel drive mechanism can be downsized. Furthermore, an optical system device such as a camera provided with the lens barrel driving mechanism can be reduced in size. Further, since the lens unit is swung around the rotation axis by the arm portion, the configuration is simple and the manufacture is easy.

  According to the lens barrel driving mechanism according to the present invention, the arm portion comes into contact with the protruding portion in accordance with the retraction operation, thereby rotating around the rotation axis to change from the photographing state to the retracted state. In the retracted state, the lens surfaces of the lens units are arranged so as to be substantially parallel, so the overall length is shortened by the length of the lens unit in the radial direction, the lens barrel drive mechanism is downsized, and this mirror is further reduced. Optical system equipment such as a camera provided with a cylinder driving mechanism can also be reduced in size. Further, the structure is simple and the manufacture is easy.

Embodiments of the present invention will be described below.
In this embodiment, a case where the lens barrel driving mechanism is applied to a digital camera exemplified as an example of an optical device will be described.
FIG. 1 is a cross-sectional view taken along the lens barrel drive mechanism according to the present embodiment and is in a tele state (photographing state), and FIG. 2 is a cross-sectional view of the storage state in which storage is completed. Shows the case. FIG. 3 is a perspective view of the third lens group 41, the third lens frame 4, and the holding frame 100 in the photographing state in the lens barrel driving mechanism, and FIG. 4 is a perspective view of the storage state.
In the following description, the state in which the digital camera can capture the widest range of subjects is called the wide state (the state in which the image can be captured in the widest range), and the state in which the subject can be captured at the highest magnification in the narrowest range. Is referred to as a tele state (a state in which imaging can be performed in the narrowest range), and a state in which each member is housed and is most compact when the digital camera is not used is referred to as a housed state.

First, the configuration of the lens barrel drive mechanism will be described with reference to FIGS.
The lens barrel drive mechanism 1 mainly includes a lens barrel body 10, a first lens frame 2, a shutter unit 8, a second lens frame 3, a third lens frame 4, a first rectilinear barrel 5A, a second rectilinear barrel 5B, and a cam. It is composed of a cylinder 6A, a rotary drive cylinder 6B, and a fixed cylinder 7. And each member 2-8 is hold | maintained in the lens-barrel main body 10 in the state in which the optical axis which passes along the approximate center of each member 2-8 substantially corresponds.

The lens barrel body 10 is provided on the outermost side, and the imaging unit 9 is attached to the rear end opening.
Further, in the lens barrel body 10, an arm portion 43 of a third lens frame 4 described later comes into contact with the retraction operation, so that the arm portion 43 is swung to bring the third lens frame 4 out of the optical path. A protrusion 103 that moves in the retracting direction is provided.

  The fixed cylinder 7 is provided on the inner side of the lens barrel main body 10, and a first rectilinear groove 71 parallel to the helicoid along the optical axis direction is provided on the inner peripheral surface thereof.

The rotational drive cylinder 6B is provided inside the fixed cylinder 7, and a helicoid is provided on the outer peripheral surface thereof, and is screwed with the helicoid of the fixed cylinder 7. The helicoid on the outer periphery of the rotary drive cylinder 6B is provided with a gear portion (not shown) and is gear-coupled with a drive motor (not shown).
Further, a second rectilinear groove 61B parallel to the optical axis direction is provided on the inner peripheral surface of the rotary drive cylinder 6B.

  The first rectilinear cylinder 5A is provided on the inner side of the rotary drive cylinder 6B, and protrudes outward from the side wall portion at the rear end portion thereof, and engages with the first rectilinear groove 71 of the fixed cylinder 7. Is provided. As a result, while the rotational drive cylinder 6B rotates and moves back and forth along the optical axis direction, the first rectilinear cylinder 5A moves back and forth while being restricted from rotating in the circumferential direction.

The cam cylinder 6A is provided inside the rotary drive cylinder 6B, and a pin 61A that fits into the second rectilinear groove 61B on the inner peripheral surface of the rotary drive cylinder 6B is provided at the rear end portion of the outer peripheral face. The pin 61A is inserted into the first cam groove 52A of the first rectilinear cylinder 5A. Therefore, the rotation of the rotary drive cylinder 6B is transmitted to the cam cylinder 6A, and the cam cylinder 6A itself is moved back and forth along the optical axis direction by the first cam groove 52A.
A second cam groove 62A that engages with the first frame portion 22 of the first lens frame 2 is formed on the outer peripheral surface of the cam cylinder 6A, and the shutter unit 8 is provided on the inner peripheral surface. A third cam groove 63A with which the second frame portion 85 is engaged is formed. Further, the second cam groove 62A is formed deeper than the third cam groove 63A in order to easily withstand the impact when the camera is dropped.

  The second rectilinear cylinder 5B is disposed in front of the first rectilinear cylinder 5A and is provided inside the rotational drive cylinder 6B. A fourth rectilinear groove 51B parallel to the optical axis direction is provided on the inner peripheral surface of the second rectilinear cylinder 5B.

The first lens frame 2 is provided on the inner side of the second rectilinear cylinder 5B, and holds the first lens group 21 at its front end. A side wall portion at the rear end portion of the first lens frame 2 is provided with a first frame portion 22 that penetrates the side wall portion and protrudes inward from the inner peripheral surface thereof. Further, a second rotation restricting portion 23 that protrudes outward and engages with the fourth rectilinear groove 51B of the second rectilinear cylinder 5B is provided on the side wall portion at the rear end portion of the first lens frame 2. As a result, the rotation of the first lens frame 2 in the circumferential direction is restricted and moves back and forth.
A caliper ring 24 and a barrier mechanism are attached to the front end portion of the first lens frame 2 where the first lens group 21 is provided.
The barrier mechanism includes a barrier drive ring and barrier blades 25 that are opened and closed by the barrier drive ring.

The shutter unit 8 is disposed behind the first lens frame 2 and is provided inside the cam cylinder 6A. The shutter unit 8 includes a shutter substrate 81 in which an exposure opening is formed, a shutter blade 83 that opens and closes or opens the exposure opening, a drive source that drives the shutter blade 83, and a cam cylinder that is fixed to the shutter substrate 81. And a mounting member 82 engaged with the rear end of 6A.
Further, the rear end portion of the attachment member 82 is provided with a third rotation restricting portion 84 in which a side wall portion at the rear end portion protrudes outward and engages with the cam cylinder 6A. Therefore, the attachment member 82 moves back and forth while the movement in the circumferential direction is restricted by the third rotation restricting portion 84.
Further, the side wall portion of the mounting member 82 is provided with a second frame portion 85 that penetrates the side wall portion, protrudes outward from the outer peripheral surface thereof, and engages with the third cam groove 63A of the cam cylinder 6A. .
Further, the driving source drives the shutter blade 83 based on a command from a control circuit (not shown) provided in the camera, thereby opening and closing the exposure opening or narrowing it to a predetermined aperture.

The second lens frame 3 is disposed behind the shutter unit 8 and holds the second lens group 31 at its front end.
The second lens frame 3 has a slide moving means (not shown) that is slidable between a position where the second lens frame 3 is disposed in the optical path and a position where the second lens frame 3 is retracted outside the optical path in accordance with the retraction operation. Is provided. As the slide moving means, for example, a pair of guide shafts inserted through the left and right side surfaces of the second lens frame 3 and slidably supporting the second lens frame 3 up and down, and a first guide shaft along the guide shaft. Examples include a drive lever that drives the two-lens frame 3, a gear that drives the drive lever, and the like, and a conventionally used mechanism can be applied.

  The third lens frame 4 is disposed behind the second lens frame 3 and holds the third lens group 41 at its front end. Further, as shown in FIGS. 3 and 4, a substantially rectangular frame-shaped holding frame 100 having an opening 100 a is disposed behind the third lens frame 4, and the third lens frame is disposed on the holding frame 100. 4 is attached. Leg portions 101 extending downward are provided on the left and right sides of the lower end surface of the holding frame 100. The third lens group 41 is housed in the space between the both leg portions 101 by swinging an arm portion 43 described later. In addition, rotating shafts 102 that protrude in a direction perpendicular to the optical axis direction are attached to the left and right sides of the holding frame 100.

The third lens frame 4 includes a frame main body 42 having an opening 42a into which the third lens group 41 is fitted, and a pair of arm parts 43 provided on the left and right side surfaces of the frame main body 42 and extending rearward. And.
The frame main body 42 has a substantially rectangular frame shape, and the arm portions 43 extend from the left and right side surfaces of the frame main body 42 to the left and right side surfaces of the rear holding frame 100. A through hole 45 is formed in the rear end portion of the arm portion 43, and the rotating shaft 102 protruding outward from the side surface of the holding frame 100 is inserted into the through hole 45. As a result, the arm portion 43 is connected to the holding frame 100 so as to be rotatable about the rotation shaft 102, and the arm portion 43 is disposed so that the lens surface of the third lens group 41 is substantially orthogonal to the optical axis direction. Storage in which the photographing state (in FIG. 3, the lens surface faces the opening 42a of the frame body 42) and the lens surface of the third lens group 41 are substantially parallel to the optical axis direction. It is possible to swing between the states (in FIG. 4, the lens surface is opposed to the lower surface of the frame main body 42).
In addition, a torsion spring 104 is provided between the arm portion 43 and the holding frame 100 to urge the arm portion 43 to a position for holding the arm portion 43 in the photographing state with respect to the holding frame 100. (See FIGS. 1 and 2). One end portion of the torsion spring 104 is fixed to the arm portion 43, and the other end portion is fixed to the holding frame 100. Therefore, the arm portion 43 is arranged in the optical path by the urging force of the torsion spring 104 to be in the shooting state, and is placed outside the optical path by swinging against the urging force of the torsion spring 104 and in the stored state. It is considered as a position

  Further, a substantially rectangular convex portion 44 is formed at the rear end portion of the arm portion 43. Of the rear end surface of the convex portion 44 (the rear end surface when the arm portion 43 is held in the photographing state as shown in FIG. 3), the upper portion 44 a is a substantially rectangular protrusion disposed behind the holding frame 100. Of the front end surface of 103, the lower part 103a is contacted, and a rotational force is applied to the arm part 43 by the contact. Accordingly, the arm portion 43 to which the rotational force is applied swings around the rotation shaft 102 (counterclockwise in FIG. 3) against the urging force and moves downward, and the convex portion 44 moves to the lower surface of the projection portion 103. (See FIG. 4). At this time, the third lens group 41 is housed in the space between the both leg portions 101 of the holding frame 100. When the engagement between the convex portion 44 and the protrusion 103 is released, the arm portion 43 again swings around the rotation shaft 102 (clockwise in FIG. 4) by the urging force and moves upward.

  A motor (not shown) for adjusting the position of the third lens group 41 is connected to the outer periphery of the third lens frame 4, and the third lens group 41 and the motor are rotated by rotating the motor. The distance from the image pickup unit 9 disposed behind the third lens group 41 is adjusted so that the focus is achieved.

  The imaging unit 9 includes a receiving portion 91 attached to the inner peripheral rear end portion of the lens barrel body 10, a low-pass filter 92 fitted in the receiving portion 91, and an elastic body (not shown) at the rear portion of the low-pass filter 92. An image pickup device 93 provided and a pressing plate 94 that sandwiches the image pickup device 93 with a low-pass filter 92 are provided.

Next, the operation of the lens barrel drive mechanism 1 will be described.
As shown in FIG. 2, when the driving force from the motor (not shown) is transmitted to the gear portion (not shown) of the rotation driving cylinder 6B to the lens barrel driving mechanism 1 in the retracted state, the rotation driving cylinder 6B rotates. To do. Along with the rotation of the rotation driving cylinder 6B, the first rotation restricting portion 51A of the first rectilinear cylinder 5A moves straight forward along the first rectilinear groove 71. At the same time, the rotation of the rotary drive cylinder 6B is transmitted to the pin 61A of the cam cylinder 6A, and the cam cylinder 6A advances straight forward along the first cam groove 52A of the first rectilinear cylinder 5A. With the rotation of the cam cylinder 6A, the third rotation restricting portion 84 also moves straight forward, and the first frame portion 22 of the first lens frame 2 moves straight along the second cam groove 62A. Further, the second frame portion 85 of the shutter unit 8 advances straight forward along the third cam groove 63A.
At this time, the first rotation restricting portion 51A of the first rectilinear cylinder 5A is restricted from moving in the circumferential direction by the first rectilinear groove 71, and the second rotation restricting portion 23 is surrounded by the fourth rectilinear groove 51B of the second rectilinear cylinder 5B. Since the movement in the direction is restricted and the movement in the circumferential direction is restricted in the third rotation restricting portion 84, both move in the optical axis direction without rotating in synchronization with the rotation drive cylinder 6B or the cam cylinder 6A. To do.

On the other hand, in the stored state of FIG. 4, the arm portion 43 swings around the rotation shaft 102 (counterclockwise in FIG. 4) against the urging force, and the third lens group 41 has a lens surface with respect to the optical axis direction. Are arranged so as to be substantially parallel, that is, downward in FIG. At this time, the protrusion 44 is locked by the protrusion 103. The second lens group 31 is slid and moved rearward and upward of the shutter unit 8 by a slide moving means (not shown) (see FIG. 2). The second lens group 31 is arranged so that its lens surface is substantially parallel to the optical axis direction.
As shown in FIG. 1, the second lens frame 3 slides downward from this stored state and is disposed in the optical path as the shutter unit 8 moves. At this time, in the third lens frame 4, when the holding frame 100 moves forward, the convex portion 44 of the arm portion 43 is disengaged from the protruding portion 103, and the arm portion 43 is rotated by the urging force of the torsion spring 104. Swinging around, the third lens group 41 is arranged so that the lens surface is substantially orthogonal to the optical axis direction. As a result, a shooting state is established.

Thereafter, when the cam cylinder 6A is rotated by a predetermined distance, the first lens frame 2 is extended to be in a wide state (not shown). The first lens frame 2 is in the widened state and is in the most extended state. When the cam barrel 6A is further rotated, the first lens frame 2 is once retracted and then retracted from the middle until reaching the tele state (see FIG. 1). ). At this time, the shutter unit 8 is extended forward by the guide of the third cam groove 63A that engages with the second frame portion 85, and performs zooming by changing the group interval.
Further, a motor (not shown) adjusts the position of the third lens frame 4 and moves the third lens group 41 according to the positions of the first lens group 21 and the second lens group 31, so that the focus is imaged. It will fit part 9.

  In the operation of returning from the tele state to the wide state and further storing the lens groups 21, 31, and 41, the rotation drive cylinder 6B and the cam cylinder 6A rotate in the opposite direction to that during the extension. Due to these rotations, the first lens frame 2 in the wide state is retracted by the guide of the second cam groove 62A, and the shutter unit 8 is retracted by the guide of the third cam groove 63A, and the third rotation restricting portion 84. Is carried in at the same time. Further, the first rectilinear cylinder 5 </ b> A is retracted by guiding the first rectilinear groove 71.

At this time, a rotational force is applied to the arm portion 43 as the convex portion 44 of the arm portion 43 comes into contact with the protruding portion 103 as shown in FIG. As a result, the arm portion 43 swings counterclockwise, and the convex portion 44 is locked on the lower surface of the protruding portion 103. As a result, the third lens group 41 is moved downward with respect to the holding frame 100, the lens surface of the third lens group 41 is arranged substantially parallel to the optical axis direction, and the space between the leg portions 101 is set. (See FIG. 4). Further, the slide moving means slides the second lens frame 3 upward by the retraction operation of the shutter unit 8 and arranges it behind the shutter unit 8.
Thereafter, the barrier blade 25 is closed at a predetermined position.

As described above, according to the lens barrel drive mechanism of the embodiment of the present invention, the rotational force is applied to the third lens frame 4 by the arm portion 43 abutting against the projection portion 103 in accordance with the retraction operation. It rotates about the rotation axis 102 and swings from a shooting state in which the lens surface of the third lens group 41 is disposed substantially orthogonal to the optical axis direction to a storage state in which the lens surface is disposed substantially in parallel. . In the retracted state, the lens surface of the third lens group 41 is arranged so as to be substantially parallel, and therefore the overall length is shortened by the length of the third lens group 41 in the radial direction. In addition, a small device such as a camera can be miniaturized. Further, since the third lens group 41 is swung around the rotation shaft 102 by the arm portion 43, the structure is simple and the manufacture is easy.
Furthermore, in the second lens frame 3, the slide movement means slides the second lens frame 3 from the position where the second lens frame 3 is disposed in the optical path to the position where the second lens frame 3 is retracted outside the optical path. Other members and the like are arranged at the positions of the second lens group 31 and the second lens frame 3, and the entire thickness can be reduced accordingly.

In addition, this invention is not limited to the said embodiment, In the range which does not deviate from the summary, it can change suitably.
For example, in the above-described embodiment, the shapes of the arm portion 43, the holding frame 100, and the protruding portion 103 are not limited to those described above, and the third lens group 41 is swung as described above by swinging the arm portion 43 around the rotation shaft 102. As long as it has the same action that can switch between the shooting state and the storage state, it can be changed as appropriate.
In addition, as the arm portion 43 comes into contact with the protruding portion 103 during the retraction operation, the arm portion 43 swings downward against the urging force, and the protruding portion 44 of the arm portion 43 is locked to the protruding portion 103 and is stored. On the other hand, with the feeding operation, the projection 44 and the projection 103 are unlocked, and the arm 43 is swung upward again to be in a shooting state. The arm portion 43 swings upward against the urging force when the convex portion 44 comes into contact with the portion 103, and the latching between the convex portion 44 and the protruding portion 103 is released, and the swing may be made downward. . In this case, the arm unit 43 may be configured to swing clockwise during the retraction operation and to swing counterclockwise during the retraction operation.

  Further, the second lens group 31 and the second lens frame 3 are also slid upward in the retracting operation by the second slide moving means to be in the storage state, but are slid downward to be in the storage state. You may comprise as follows.

  In addition, the fixed cylinder 7 and the rotation driving cylinder 6B are driven by a helicoid structure, but the present invention is not limited to this and may be driven by a cam structure. In addition, in the above embodiment, the member driven by the cam structure may be driven by the helicoid structure.

  Furthermore, in the above embodiment, the three lens groups of the first lens group 21, the second lens group 31, and the third lens group 41 are provided, but a configuration including two lens groups may be used. A configuration including four or more lens groups may be used.

FIG. 5 is a cross-sectional view taken along the optical axis in the photographing state of the lens barrel drive mechanism for illustrating an embodiment of the present invention. It is sectional drawing along the optical axis in the accommodation state of a lens-barrel drive mechanism. It is a perspective view in the imaging state of the third lens group, the third lens frame, and the holding frame. FIG. 6 is a perspective view of the third lens group, the third lens frame, and the holding frame in the stored state.

Explanation of symbols

3 Second lens frame (front lens frame)
4 Third lens frame (rear lens frame)
31 Second lens group (front lens group)
41 Third lens group (rear lens group)
43 Arm part 100 Holding frame (holding part)
102 Rotating shaft 103 Projection

Claims (1)

A front lens frame that holds the front lens group;
A rear lens frame that holds the rear lens group;
A holding part that is disposed on the rear side of the rear lens frame and holds the rear lens frame;
A protrusion disposed on the further rear side of the holding portion, and with the retraction operation, the protrusion contacting the rear lens frame;
The rear lens frame extends rearward from the periphery of the rear lens group, and has an arm portion provided on the holding portion so as to be rotatable about a rotation axis that intersects the optical axis direction. And
The arm portion is rotated by being brought into contact with the protruding portion in accordance with the retraction operation, rotates around the rotation axis, and the lens surface of the lens group in the optical path is in the optical axis direction. The lens barrel swings from an imaging state arranged so as to be substantially orthogonal to an accommodation state where the lens surface of the lens group is arranged substantially parallel to the optical axis direction outside the optical path. Drive mechanism.

Images