JP2006058455A - Lens barrel driving mechanism - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lens barrel driving mechanism for preventing loss of power and errors of operation by hardly generating inclination of an optical axis, making impact from the outside strong, and attaining thinning. <P>SOLUTION: The lens barrel driving mechanism 100 comprises a lens group L3a and a cam cylinder 5 for moving the lens group L3a at prescribed displacement in an optical axis direction. The lens barrel driving mechanism 100 is provided with a lens group holding cylinder 3 capable of being moved to the cam cylinder 5 in the inside of the cam cylinder 5 in the optical axis direction and a pair of guide shafts 31 vertically extending in a lens group holding cylinder 3, supporting an outer peripheral both end part of the lens group (for instance, a third lens group L3), and movable between a position arranging the lens group in an optical path and a position retreated out of the optical path. The lens group holding cylinder 3 includes a lens group moving means 9 giving rotation motion by the rotation of the cam cylinder 5 accompanying transferring operation and moving the lens group L3a at a position retreated out of the optical path from a position arranged in the optical path along the guide shaft 31. <P>COPYRIGHT: (C)2006,JPO&NCIPI

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 of rotating the optical element about the axis as used in the bifocal switching camera and retracting it is used (for example, see Patent Document 1). That is, the lens frame that holds the lens group is provided with a swing arm that is pivotally supported so as to be rotatable about an axis, and the swing arm pivots around the axis in accordance with a retraction operation or a retraction operation. As a result, the lens frame is disposed in the optical path or retracted out of the optical path. As a result, the photographing state or the retracted state is set.
In addition, there is known a method for retracting the lens group along a guide shaft extending vertically, which is perpendicular to the optical axis direction, without using a swing arm. In this case, when the lens barrel is retracted, power is applied to the drive lever by the lens group coming into contact with the protrusion provided in the optical axis direction on the wall of the barrel main body. As a result, the lens group is retracted along the guide shaft.
JP 2003-315861 A

However, in the camera described in Patent Document 1, since the lens group is rotated to be retracted out of the optical path by rotating the swing arm about the axis, it receives an external shock in the photographing state. In this case, the optical axis of the lens group may be easily tilted. In particular, in the present state of downsizing to the limit, the performance may be greatly deteriorated even by this slight inclination. Further, because of the compactness, there is a problem that the rotation axis cannot be made long, and the lens group tends to be inclined with a short rotation axis.
In addition, in a camera that uses the guide shaft and retracts in a direction perpendicular to the optical axis direction without using a swing arm, for example, when retracting, a motor as a power source is driven and repeated. Each lens barrel is rotated and retracted by the insertion operation, the lens group comes into contact with the protrusion, and the drive lever is driven to retract the lens group out of the optical path along the guide shaft. As described above, there are many processes in which the power from the motors serving as all power sources is transmitted, and considerable steps are required to drive the retracted lens group. Therefore, this process has caused power loss and operation error.
Further, in the above camera, the lens group is configured to come into contact with the protruding portion of the wall portion of the lens barrel body as the retracting operation is performed, so that unnecessary force is applied to the wall portion of the lens barrel body. Since the wall portion itself needs a certain level of strength, it is necessary to ensure the thickness of the wall portion, and it is difficult to realize a reduction in thickness.

  The present invention has been made in view of the above circumstances, and it is difficult to tilt the optical axis, is resistant to external impact, can be thinned, and prevents power loss and operation error. It is an object of the present invention to provide a lens barrel drive mechanism that can do this.

In order to solve the above-described problem, the invention of claim 1 includes a lens group (for example, a third lens group L3a) as shown in FIGS.
A lens barrel drive mechanism 100 including a cam barrel 5 that moves the lens group in the optical axis direction with a predetermined displacement;
A lens group holding cylinder 3 that is movable in the optical axis direction with respect to the cam cylinder is provided inside the cam cylinder,
In the lens group holding cylinder, it extends vertically and supports both ends of the outer periphery of the lens group (for example, the third lens group L3a). The lens group is placed in the optical path and outside the optical path. A pair of guide shafts 31 that are movable between the retracted positions are provided,
The lens group holding cylinder is rotated by the rotation of the cam cylinder accompanying the retraction operation, and moves from the position where the lens group is disposed in the optical path along the guide shaft to a position where the lens group is retracted outside the optical path. The lens group moving means 9 is provided.

According to the first aspect of the present invention, the lens group moving means is given a rotational movement by the rotation of the cam cylinder accompanying the retraction operation, and the lens group is moved out of the optical path from the position arranged in the optical path along the guide shaft. Since the lens group is moved to the retracted position, unlike the conventional case, the lens group can be moved in a stable state by being supported at two locations by a pair of guide shafts, and even when subjected to external impact, the lens group can be moved. The inclination of the optical axis caused by the above can be prevented, thus leading to the prevention of performance degradation.
In addition, the lens group can be placed in the retracted state and the photographing state by the lens group moving means that is given rotational movement with the rotation of the cam barrel as direct power. Then, the power transmission process until the lens group moves in or out of the optical path is short, which leads to prevention of power loss and operation error.

The invention of claim 2 is a lens barrel drive mechanism according to claim 1, for example, as shown in FIGS.
The lens group moving means includes a cam cylinder convex portion 91 formed on the inner peripheral surface of the cam cylinder,
A lever member 92 that is rotatable about the shaft center by abutting the convex portion of the cam barrel rotating with the rotation of the cam barrel;
The lever member supports the lens group at a tip portion thereof, and moves the lens group between the inside and outside of the optical path along the guide shaft by the rotation of the lever member.

  According to the second aspect of the present invention, the lens group moving means includes the cam tube convex portion and the lever member, and rotates around the axis by the lever member coming into contact with the cam tube convex portion as the cam tube rotates. As a result, the lever member supports the lens group at its distal end and moves between the inside and outside of the optical path along the guide axis. Because of such a configuration, unlike the conventional configuration in which the lens group is in contact with the projection of the wall portion of the barrel main body, no unnecessary force is applied to the wall portion of the barrel main body. Therefore, it is possible to reduce the thickness of the lens barrel drive mechanism without securing the thickness of the lens barrel body. Furthermore, it is possible to reduce the thickness of a camera or the like provided with this lens barrel drive mechanism.

The invention of claim 3 is, for example, as shown in FIGS. 1 to 6, in the lens barrel drive mechanism according to claim 1 or 2,
Rotation restricting means (for example, a first stopper portion 98 and a second stopper portion 99) for stopping the rotation of the lever member at a position where the lens group is disposed in the optical path and a position where the lens group is retracted outside the optical path, respectively. It is characterized by.

  According to the invention of claim 3, since the rotation of the lever member is stopped by the rotation restricting means, the lens group supported by the lever member can be reliably arranged at a predetermined position inside or outside the optical path.

According to the lens barrel driving mechanism according to the present invention, the lens group moving means is given a rotational movement by the rotation of the cam cylinder accompanying the retraction operation, and from the position where the lens group is arranged in the optical path along the guide axis. Since the lens group is moved to a position to be retracted out of the optical path, the lens group can be supported in two positions by a pair of guide shafts and can be moved in a stable state. The resulting tilt of the optical axis can be prevented, leading to prevention of performance degradation.
In addition, since the lens group can be arranged in the retracted state and the photographing state by the lens group moving means provided with the rotational movement using the rotation of the cam cylinder as direct power, the lens after the motor as the power source is driven. The power transmission process until the group moves in or out of the optical path is short, thus leading to prevention of power loss and operation error.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
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 along the optical axis of the lens barrel driving mechanism according to the present embodiment and shows a retracted state, FIG. 2 is a top view in FIG. 1, and FIG. FIG. 4 is a front view in the wide state.
In the following description, the wide state refers to a state in which the digital camera can capture the widest range of subjects (capable of capturing images in the widest range), and the retracted state refers to a state in which the digital camera is not used. The state where each member is accommodated and made the most compact shall be said.

First, the main configuration of the lens barrel drive mechanism will be described with reference to FIGS.
The lens barrel drive mechanism 100 mainly includes a lens barrel body 1, a first lens frame L1, a second lens frame L2, a shutter unit 2, a third lens frame L3, a fourth lens frame L4, a lens group holding cylinder 3, and a straight advance. It is composed of a cylinder 4, a cam cylinder 5, a rotating cylinder 6, and a fixed cylinder 7. And each member L1-L4, 1-7 is hold | maintained in the lens-barrel main body 1 in the state in which the optical axis which passes along the approximate center of each member L1-L4, 1-7 substantially corresponds.

The lens barrel body 1 is provided on the outermost side, and an imaging unit 8 is attached to the rear end opening.
The imaging unit 8 includes a receiving part attached to the inner peripheral rear end of the lens barrel body 1, a low-pass filter fitted into the receiving part, a light receiving element provided via an elastic body at the rear part of the low-pass filter, A holding plate or the like that sandwiches the light receiving element with a low-pass filter is provided.

  A fixed cylinder 7 is provided inside the lens barrel body 1. A rotating cylinder 6 is provided inside the fixed cylinder 7, and a helicoid 71 formed on the inner peripheral surface of the fixed cylinder 7 and a helicoid 61 formed on the outer peripheral surface of the rotating cylinder 6 are screwed together. Yes. The helicoid 61 on the outer peripheral surface of the rotary cylinder 6 is provided with a gear portion (not shown) and is gear-connected to a drive motor (not shown).

A rectilinear cylinder 4 is fitted in the rotating cylinder 6. The rectilinear cylinder 4 is provided with a rotation restricting portion 41 that protrudes outward on the side wall portion at the rear end portion thereof. When the rotation restricting portion 41 is engaged with the rectilinear groove 72 formed in the fixed cylinder 7, the rectilinear cylinder 4 can move straight in the optical axis direction without rotating.
Further, the connecting piece 51 protruding from the outer periphery of the cam cylinder 5 is inserted into the insertion groove 42 formed in the rectilinear cylinder 4. The connecting piece 51 is engaged with a cam cylinder driving rectilinear groove 62 formed on the inner periphery of the rotating cylinder 6. As a result, when the rotary cylinder 6 rotates, the cam cylinder 5 rotates in the same manner.

  A cam cylinder 5 is provided inside the rotary cylinder 6. The first frame portion K1 protruding from the inner periphery of the first lens frame L1 is engaged with the first cam groove 52 formed on the outer peripheral surface of the cam cylinder 5. Further, the second frame portion K2 protruding from the outer periphery of the second lens frame L2 is engaged with the second cam groove 53 formed on the inner peripheral surface of the cam cylinder 5. The first cam groove 52 is formed deeper than the second cam groove 53 in order to easily withstand the impact when the camera is dropped.

A lens group holding cylinder 3 is provided inside the cam cylinder 5 and behind the second lens frame L2. Three third frame portions K3 are provided on the outer peripheral surface of the lens group holding cylinder 3, and these third frame portions K3 engage with a third cam groove 54 formed on the inner peripheral surface of the cam tube 5. (See FIGS. 2 and 3). Thus, when the cam cylinder 5 rotates, the lens group holding cylinder 3 also rotates in the same manner.
A shutter unit 2 is provided in front of the opening of the lens group holding cylinder 3. The shutter unit 2 includes a shutter substrate 21 on which an exposure opening is formed, a shutter blade 22 that opens and closes or opens the exposure opening, a drive source (not shown) that drives the shutter blade 22, and the like. A spring 23 is attached between the shutter unit 2 and the second lens frame L2.

In the lens group holding cylinder 3, as shown in FIGS. 3 and 4, the third lens frame L3 is arranged in the optical path, extending vertically and supporting both ends of the outer periphery of the third lens frame L3. A pair of guide shafts 31 that are movable between a position to be retracted and a position to be retracted outside the optical path are provided.
The guide shaft 31 is inserted into the side wall portion of the third lens frame L3, and one guide shaft 31 is inserted with a compression spring 32 that urges the third lens frame L3 downward in the drawing.
Further, as will be described later, the lens group holding cylinder 3 is rotated by the rotation of the cam cylinder 5 as the cam cylinder 5 is retracted, and the third lens frame L3 is moved along the guide shaft 31 into the optical path. There is a lens group moving means 9 for moving the lens from a position where it is disposed to a position where it is retracted from the optical path.

  A fourth lens frame L4 that holds the fourth lens unit L4a at its front end is provided behind the third lens frame L3. A motor (not shown) for adjusting the position of the fourth lens unit L4a is connected to the outer periphery of the fourth lens frame L4. As the motor rotates, the distance between the fourth lens unit L4a and the imaging unit 8 disposed behind the fourth lens unit L4a is adjusted to achieve focus.

Next, the lens group moving means 9 which is a characteristic part of the present invention will be described with reference to FIGS.
The lens group moving means 9 includes a cam cylinder convex portion 91 and a lever member 92. The cam cylinder protrusion 91 is formed on the inner peripheral surface of the cam cylinder 5 so as to protrude from the inner peripheral surface.

The lever member 92 is pivotally supported on a rear end surface (that is, a surface facing the optical axis direction) of the lens group holding cylinder 3 by a shaft portion 93 protruding from the rear end surface in the optical axis direction. 3 to 5 are provided with a first lever portion 94 and a second lever portion 95 which are provided to be rotatable clockwise or counterclockwise in FIGS.
The first lever portion 94 and the second lever portion 95 are coaxially supported by the shaft portion 93, and a spring 96 is hung between the first lever portion 94 and the second lever portion 95 in a direction to draw each other. Yes. The first lever portion 94 and the second lever portion 95 are usually integrated by a spring 96. For example, the second lever portion 95 is further rotated clockwise while the first lever portion 94 is stationary. If it does, the 1st lever part 94 and the 2nd lever part 95 will be in the state opened mutually against the urging | biasing force of the spring 93. FIG.
The distal end portion of the first lever portion 94 is supported by the lever member 92 rotating around the shaft portion 93 so as to be in contact with the third lens frame L3, thereby supporting the third lens frame L3 along the guide shaft 31. It is moved up and down, that is, between the inside of the optical path and the outside of the optical path.
Further, around the outer periphery of the first lever portion 94 and the second lever portion 95 supported by the shaft portion 93, the cam member 5 rides on the cam tube convex portion 91 to rotate to the lever member 92. A lever convex portion 97 that imparts motion is formed.

Further, the rear end surface of the lens group holding cylinder 3 projects in the optical axis direction in the same manner as the shaft portion 93, and a first stopper portion 98 and a second stopper portion 99 (rotation restricting means) that restrict the rotation of the lever member 92. ) Is attached.
The first stopper portion 98 abuts on the first lever portion 94 to stop the rotation of the first lever portion 94, and the third lens group L3a supported by the first lever portion 94 is disposed in the optical path. keeping.
The second stopper portion 99 abuts on the first lever portion 94 to stop the rotation of the first lever portion 94, and the third lens group L3a supported by the first lever portion 94 is retracted out of the optical path. keeping.

Next, the operation of the lens group moving means 9 configured as described above will be described.
As shown in FIGS. 5A and 6B, in the wide state in which the cam cylinder 5 is extended, the cam cylinder convex portion 91 of the cam cylinder 5 is located on the upper side in FIG. The cam cylinder protrusion 91 and the lever protrusion 97 are separated from each other. On the other hand, the third lens frame L3 inserted through the guide shaft 31 is urged downward by the urging force of the compression spring 32, is rotated downward about the shaft portion 93, and abuts on the first stopper portion 98. Thus, the rotation is supported at the distal end portion of the first lever portion 94 whose rotation is stopped. In this way, the third lens unit L3a is arranged in the optical path and is in the wide state.

  When changing from the wide state to the retracted state, the cam cylinder 5 rotates with the retraction operation, so that the cam cylinder convex portion 91 abuts on the lever convex portion 97. Then, the lever member 92 rotates clockwise around the shaft portion 93, and the third lens frame L3 supported by the distal end portion of the first lever portion 94 is pushed up against the urging force of the compression spring 32 and guided. It moves upward along the axis 31 (see FIG. 5B).

  Further, when the cam cylinder 5 rotates clockwise, the lever convex portion 97 rides on the cam cylinder convex portion 91 and moves on the cam cylinder convex portion 91. As a result, the tip end portion of the first lever portion 94 further rotates clockwise, comes into contact with the second stopper portion 99 and stops its rotation. In this way, the third lens unit L3a is pushed upward along the guide shaft 31 and retracted out of the optical path to be in a retracted state (see FIGS. 5C and 6A).

Furthermore, when the retracted state is changed to the wide state again, the cam cylinder 5 rotates counterclockwise with the feeding operation, so that the cam cylinder convex portion 91 also rotates counterclockwise. After the lever convex portion 97 riding on the portion 91 moves on the cam tube convex portion 91, it is separated from the cam tube convex portion 91. Then, the first lever portion 94 rotates counterclockwise about the shaft portion 93, and the third lens frame L3 supported by the tip end portion of the first lever portion 94 is pushed down by the urging force of the compression spring 32 and guided. It moves downward along the axis 31 (see FIG. 5B).
Further, when the cam cylinder 5 is rotated counterclockwise, the first lever portion 94 is rotated counterclockwise around the shaft portion 93, and the tip end portion abuts on the first stopper portion 98 to stop the rotation. Is done. In this way, the third lens unit L3a is pushed down along the guide shaft 31 and is disposed in the optical path to enter the wide state (see FIGS. 5A and 6B).

As described above, according to the lens barrel driving mechanism 100 of the embodiment of the present invention, the lever convex portion 97 rides on the cam cylindrical convex portion 91 due to the rotation of the cam barrel 5 accompanying the retraction operation, thereby the lever member 92. Rotates clockwise around the shaft 93, and the third lens frame L3 supported by the tip of the first lever portion 94 is pushed upward along the guide shaft 31 and retracted out of the optical path. Further, due to the rotation of the cam cylinder 5 accompanying the feeding operation, the lever convex portion 97 that has been ridden on the cam cylinder convex portion 91 is separated from the cam cylinder convex portion 91, whereby the lever member 92 is centered on the shaft portion 91. The third lens frame L3 that rotates counterclockwise and is supported by the distal end portion of the first lever portion 94 is pushed down along the guide shaft 31 and is disposed in the optical path. In this way, the lens group moving means 9 having the cam cylinder convex portion 91 and the lever member 92 is given a rotational movement by the rotation of the cam cylinder 5 to move the third lens frame L3, and therefore the third lens frame L3. Can be moved in a stable state by being supported at two locations by a pair of guide shafts 31, and even when subjected to external impact, the tilt of the optical axis caused by the movement of the third lens frame L3 can be prevented, Therefore, it leads to prevention of performance degradation.
Further, since the third lens frame L3 can be arranged in the retracted state and the photographing state by the lens group moving means 9 given a rotational motion with the rotation of the cam cylinder 5 as a direct power, a motor as a power source is provided. The power transmission process from when the third lens frame L3 is moved to when the third lens frame L3 moves in or out of the optical path is short, which leads to prevention of power loss and operation error.

Furthermore, since the lens group is different from the conventional configuration in which the lens group is in contact with the projection on the wall of the barrel main body, the thickness of the barrel main body 1 is not secured, and the lens barrel driving mechanism 100 is thinned. can do. Further, a camera or the like provided with the lens barrel driving mechanism 100 can be made thin.
In addition, since the rotation of the lever member 92 is stopped by the first stopper portion 98 and the second stopper portion 99, the third lens frame L3 can be reliably disposed at a predetermined position inside or outside the optical path.

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 embodiment, the fixed cylinder 7 and the rotating cylinder 6 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 said embodiment, it is good also as a structure which drives the member driven by a cam structure by a helicoid structure.

  Furthermore, in the above-described embodiment, the four lens groups of the first lens group L1a, the second lens group L2a, the third lens group L3a, and the fourth lens group L4a are provided. It may be a configuration.

FIG. 5 is a cross-sectional view taken along the optical axis in the retracted state of the lens barrel drive mechanism for illustrating an embodiment of the present invention. It is a top view in the retracted state of the lens barrel driving mechanism. It is a front view in the retracted state of the lens barrel drive mechanism. FIG. 3 is a front view of the lens barrel drive mechanism in a wide state. (A)-(c) is a front view for demonstrating operation | movement of a lens-barrel drive mechanism. (A) is a development view of the cam cylinder in the retracted state, and (b) is a development view of the cam cylinder in the wide state.

Explanation of symbols

3 lens group holding cylinder 5 cam cylinder 9 lens group moving means 31 guide shaft 91 cam cylinder convex part 92 lever member 98 first stopper part (rotation restricting means)
99 Second stopper (rotation restricting means)
100 Lens barrel drive mechanism L3a Third lens group (lens group)

Claims (3)

A lens group;
A lens barrel drive mechanism comprising a cam barrel that moves the lens group in the optical axis direction with a predetermined displacement;
A lens group holding cylinder that is movable in the optical axis direction with respect to the cam cylinder and holds the lens group therein is provided inside the cam cylinder,
In the lens group holding cylinder, it extends vertically and supports both outer peripheral ends of the lens group, and is movable between a position where the lens group is disposed in the optical path and a position where the lens group is retracted outside the optical path. A pair of guide shafts are provided,
The lens group holding cylinder is rotated by the rotation of the cam cylinder accompanying the retraction operation, and moves from the position where the lens group is disposed in the optical path along the guide shaft to a position where the lens group is retracted outside the optical path. A lens barrel driving mechanism comprising lens group moving means for moving the lens group. The lens group moving means includes a cam cylinder convex portion formed on an inner peripheral surface of the cam cylinder,
A lever member that is rotatable about the shaft center by abutting on the convex portion of the cam barrel rotating with the rotation of the cam barrel;
The lever member supports the lens group at a tip portion thereof, and moves the lens group between the inside and outside of the optical path along the guide shaft by rotation of the lever member. The lens barrel drive mechanism according to 1. 3. The lens barrel drive according to claim 1, further comprising a rotation restricting unit that stops the rotation of the lever member at a position where the lens group is disposed in the optical path and a position where the lens group is retracted outside the optical path. mechanism.

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