ZOOM LENS DEVICE AND OPTICAL DEVICE

Provided is a zoom lens device and an optical device with which it is possible to increase a moving distance of a moving cylinder in an optical axis direction without an increase in number of components, the moving cylinder including a lens group closest to a subject side. A zoom lens device (1) includes a fixed cylinder (30), a cam cylinder (20) that is positioned outside the fixed cylinder (30), a first movement group that is positioned outside the cam cylinder (20) and that includes a first lens group (H1) provided at a distal end portion, and a second movement group that is positioned inside the fixed cylinder (30) and that includes a second lens group (H2). The first movement group includes a first straight groove (4) that guides the first movement group straight and a first cam follower pin (3) that engages with a first cam groove formed at the cam cylinder (20), and the second movement group includes a second cam follower pin (2) that penetrates a second straight groove formed at the fixed cylinder (30) and a second cam groove formed at the cam cylinder (20) and that engages with the first straight groove (4).

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a zoom lens device and an optical device.

2. Description of the Related Art

In the related art, a technique related to movement of a movement group that moves in the case of a magnification change operation in a zoom lens device has been proposed.

Disclosed in WO2016/104547A is a zoom lens device in which two protrusion portions are separately formed on a first linear movement cylinder and two straight grooves that respectively engage with the two protrusion portions are formed on a fixed cylinder so that the length of a portion where the fixed cylinder and the first linear movement cylinder engage with each other is increased, the fixed cylinder and the first linear movement cylinder moving relative to each other.

SUMMARY OF THE INVENTION

An embodiment of the present disclosed technology provides a zoom lens device and an optical device with which it is possible to increase a moving distance of a moving cylinder in an optical axis direction without an increase in number of components, the moving cylinder including a lens group closest to a subject side.

A zoom lens device according to an aspect of the present invention includes a fixed cylinder, a cam cylinder that is positioned outside the fixed cylinder, a first movement group that is positioned outside the cam cylinder and that includes a first lens group provided at a distal end portion, and a second movement group that is positioned inside the fixed cylinder and that includes a second lens group. The first movement group and the second movement group move so that a magnification change operation is performed in a case where the cam cylinder rotates, the first movement group includes a first straight groove that guides the first movement group straight and a first cam follower pin that engages with a first cam groove formed at the cam cylinder, and the second movement group includes a second cam follower pin that penetrates a second straight groove formed at the fixed cylinder and a second cam groove formed at the cam cylinder and that engages with the first straight groove.

A zoom lens device according to another aspect of the present invention includes a fixed cylinder, a cam cylinder that is positioned outside the fixed cylinder, a first movement group that is positioned outside the cam cylinder and that includes a first lens group provided at a distal end portion, and a second movement group that is positioned inside the fixed cylinder and that includes a second lens group. The first movement group and the second movement group move so that a magnification change operation is performed in a case where the cam cylinder rotates, the first movement group includes a first straight groove that guides the first movement group straight and a first cam follower pin that engages with a first cam groove formed at the cam cylinder, and the second movement group includes a second cam follower pin that engages with the first straight groove of the first movement group via the fixed cylinder and the cam cylinder and a third cam follower pin that engages with a second straight groove formed at the fixed cylinder and a second cam groove formed at the cam cylinder.

It is preferable that the first straight groove is formed at an inner peripheral surface of the first movement group.

It is preferable that the first movement group includes one or more first straight grooves in a circumferential direction.

It is preferable that the first cam follower pin engages only with the first cam groove.

It is preferable that the cam cylinder includes a third cam groove that engages with a fourth cam follower pin provided at the fixed cylinder and the cam cylinder rotates to move in an optical axis direction with respect to the fixed cylinder.

An optical device according to still another aspect of the present invention includes the zoom lens device described above.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

First Embodiment

Hereinafter, preferred embodiments of a zoom lens device and an optical device according to the present invention will be described with reference to the accompanying drawings.

First, the related art will be described.

To be considered below is movement of a first movement group including a first lens group closest to a subject side that is made in a direction along an optical axis in a case where a magnification change operation of a zoom lens device is performed. In many cases, restriction of rotation of the first lens group and the first movement group, which includes a moving cylinder that moves integrally with the first lens group, is performed by means of a cam follower pin provided at the moving cylinder and a straight groove of a fixed cylinder. Specifically, the cam follower pin formed at the moving cylinder engages with a cam groove of a cam cylinder so that a drive force is applied to the first movement group and the cam follower pin engages with the straight groove of the fixed cylinder so that rotation of the first movement group is restricted. However, in a case where the rotation of the first movement group is restricted by means of the straight groove of the fixed cylinder in such a manner, the required length of the straight groove exceeds the length of the fixed cylinder in a case where the amount of movement of the first movement group is large, so that restriction of rotation of the first movement group cannot be performed. As a technique for solving this problem, there is also a technique of providing another set of a cam cylinder and a straight groove. However, the number of components of the zoom lens device increases and thus there is an increase in cost. In addition, there is a problem that the component cumulative error increases.

Therefore, in the present embodiment, in order to solve these problems, restriction of rotation of a first movement group is performed by means of a straight groove formed at a moving cylinder, which is a part of the first movement group, and a cam follower pin formed at a second movement group different from the first movement group. Hereinafter, the present embodiment will be described.

The configuration of the zoom lens device will be described with reference toFIGS.1to3.

FIG.1andFIG.2are cross-sectional views of a main part of the zoom lens device in the case of a magnification change operation.

FIG.1is a cross-sectional view of a zoom lens device1in a telephoto end state andFIG.2is a cross-sectional view of the zoom lens device1in a wide angle end state.FIG.3is a perspective view of a moving cylinder, a cam cylinder, and a fixed cylinder in the case of the magnification change operation of the zoom lens device1. Note that, an optical axis L of lens groups of the zoom lens device1is shown inFIGS.1to3. In addition, inFIGS.1to3, a part of the zoom lens device1that is directly related to the present embodiment is shown and the other portions are not shown. For example, inFIG.1andFIG.2, a stop and the like are not shown.

The zoom lens device1includes a moving cylinder10, a cam cylinder20, and a fixed cylinder30arranged in this order from the outside.

The moving cylinder10includes a first lens holding portion7, a first lens group H1, a first cam follower pin3, and a first straight groove4. Here, the moving cylinder10, the first lens holding portion7, the first lens group H1, the first cam follower pin3, and the first straight groove4constitute a first movement group that integrally moves in a direction along the optical axis L.

The moving cylinder10is positioned outside the cam cylinder20and includes the first lens holding portion7provided on a distal end side, which is a subject side. The first lens holding portion7holds the first lens group H1. The moving cylinder10includes the first cam follower pin3provided on a rear end side. The first cam follower pin3protrudes from an inner peripheral surface of the moving cylinder10and engages with a first cam groove22(refer toFIG.3) of the cam cylinder20. Note that, as described above, in the related art, the first cam follower pin3also engages with a straight groove formed at the fixed cylinder30so that restriction of rotation of the first movement group is performed. However, the first cam follower pin3of the present embodiment engages only with the first cam groove22of the cam cylinder20and a straight groove for the first movement group is not formed at the fixed cylinder30.

At the inner peripheral surface of the moving cylinder10, the first straight groove4for the first movement group, which does not penetrate the inner peripheral surface, is formed. The first straight groove4is formed to extend in a linear shape connecting a proximal end portion side and a distal end portion side of the moving cylinder10in the direction along the optical axis L. The first straight groove4has, for example, a recessed shape and engages with a second cam follower pin2that has a protruding shape. In a case where the first movement group including the moving cylinder10moves, the moving cylinder10moves in the direction along the optical axis L with the second cam follower pin2abutting against and sliding on the first straight groove4. Note that, one or more first cam follower pins3and one or more first straight grooves4may be provided in a circumferential direction of the moving cylinder10and it is preferable that three first cam follower pins3and three first straight grooves4are formed at equal intervals in the circumferential direction. In addition, the number of second cam follower pins2formed is the same as the number of first straight grooves4formed.

The moving cylinder10moves in the direction along the optical axis L with the cam cylinder20rotating around the optical axis L. Specifically, the first cam follower pin3formed at the moving cylinder10engages with the first cam groove22(FIG.3) of the cam cylinder20. Therefore, in a case where the cam cylinder20rotates, the first cam follower pin3is driven and the moving cylinder10moves in a front-rear direction along the optical axis L. Here, in the case of movement in the direction along the optical axis L, a rotational force acts on the moving cylinder10with the first cam follower pin3being driven. However, since the first straight groove4engages with the second cam follower pin2, rotation of the moving cylinder10is restricted and the moving cylinder10is guided straight.

The cam cylinder20includes at least the first cam groove22, a second cam groove24, and a third cam groove26(refer toFIG.3(note that, the third cam groove26is not shown inFIG.3)). The first cam groove22engages with the first cam follower pin3formed at the moving cylinder10. The second cam groove24engages with a fixation cam follower pin6(a fourth cam follower pin) formed at the fixed cylinder30. The third cam groove26engages with the second cam follower pin2formed at a base frame9.

The cam cylinder20rotates around the optical axis L. In a case where the cam cylinder20rotates, the first cam follower pin3engaging with the first cam groove22is guided in the direction along the optical axis L and the circumferential direction. In addition, in a case where the cam cylinder20rotates, the cam cylinder20is guided with respect to the fixed cylinder30in the direction along the optical axis L and the circumferential direction because of the action of the fixation cam follower pin6and the second cam groove24engaging with each other.

The fixed cylinder30includes the base frame9, a focus unit5, a proximal end portion lens holding portion11, and the fixation cam follower pin6. The base frame9includes a second lens holding portion9A, a third lens holding portion9B, and the second cam follower pin2. The base frame9, the second lens holding portion9A, the third lens holding portion9B, and the second cam follower pin2constitute a second movement group. The second lens holding portion9A holds a second lens group H2and the third lens holding portion9B holds a third lens group H3. In addition, the second cam follower pin2that engages with the first straight groove4is formed on a distal end side of the base frame9.

The focus unit5includes a focus lens group and adjusts the focus of a subject image by moving the focus lens group along the optical axis L. Note that a detailed description of the focus unit5will be omitted.

The proximal end portion lens holding portion11includes a proximal end portion lens group H4. In addition, a proximal end side of the fixed cylinder30is fixed by a base member40. A mount (not shown) is integrally attached to the base member40and is attached to a main body (the optical device). Note that the zoom lens device1can be attached to various optical devices. For example, examples of the optical device to which the zoom lens device1is attached include a binocle, a microscope, an interchangeable lens camera, and an integrated-lens camera.

The fixation cam follower pin6is formed to protrude from the fixed cylinder30and engages with the second cam groove24formed at the cam cylinder20. In a case where the cam cylinder20rotates around the optical axis L, the cam cylinder20moves forward and backward with respect to the fixed cylinder30along the optical axis L.

Next, the second cam follower pin2of the present embodiment will be described with reference toFIGS.4and5.FIG.4is a perspective sectional view showing the second cam follower pin2of the present embodiment. In addition,FIG.5is a view showing a second straight groove32provided at the fixed cylinder30and the second cam follower pin2engaging with the second straight groove32.

The second cam follower pin2of the present embodiment penetrates the fixed cylinder30and the cam cylinder20. Specifically, the second cam follower pin2engages with and penetrates the second straight groove32for the second movement group that is provided at the fixed cylinder30and the second cam follower pin2engages with and penetrates the third cam groove26provided at the cam cylinder20. In addition, the second cam follower pin2penetrating the cam cylinder20engages with the first straight groove4formed at the moving cylinder10.

The second cam follower pin2engages with the first straight groove4, restricts rotation of the moving cylinder10, and guides the moving cylinder10straight along the optical axis L.

In addition, since the second cam follower pin2engages with the third cam groove26formed at the cam cylinder20and engages with the second straight groove32formed at the fixed cylinder30, the second cam follower pin2is driven along the optical axis L in a case where the cam cylinder20rotates around the optical axis L. Accordingly, the second movement group including the base frame9moves along the optical axis L.

As described above, in the present embodiment, the first straight groove4for guiding the first movement group straight is formed at the moving cylinder10included in the first movement group. In addition, the second cam follower pin2formed at the base frame9included in the second movement group penetrates the fixed cylinder30and the cam cylinder20and engages with the first straight groove4. Therefore, restriction of rotation of the moving cylinder10is performed by means of the first straight groove4and the second cam follower pin2. Accordingly, a moving distance of the moving cylinder10in the direction along the optical axis L can be made large regardless of the length of the fixed cylinder30. In addition, according to the present embodiment, a cam cylinder does not need to be added to form a long straight groove, so that it is possible to make the number of components of the zoom lens device1small.

Furthermore, in the present embodiment, the second cam follower pin2engages with the first straight groove4, engages with the second straight groove32formed at the fixed cylinder30, and engages with the third cam groove26formed at the cam cylinder20. Therefore, the second cam follower pin2guides the moving cylinder10straight and is driven in the direction along the optical axis L of the second movement group. Accordingly, it is possible to make the number of components of the zoom lens device1small in comparison with a case where a cam follower pin that engages with the first straight groove4and a cam follower pin that engages with the third cam groove26and the second straight groove32are formed.

Second Embodiment

Next, a second embodiment will be described. In the present embodiment, as with the first embodiment, the second cam follower pin2guides the moving cylinder10straight. Furthermore, in the present embodiment, a third cam follower pin8is formed and the third cam follower pin8guides the second movement group straight.

Next, the second cam follower pin2and the third cam follower pin8of the present embodiment will be described with reference toFIGS.6and7.FIG.6is a perspective sectional view showing the second cam follower pins2and the third cam follower pin8. Note that, inFIG.6, the first cam groove22with which the first cam follower pin3engages is not shown.FIG.7is a perspective sectional view showing the second cam follower pin2. Note that, inFIG.7, the second lens holding portion9A is not shown.

The second cam follower pins2and the third cam follower pin8are formed at the base frame9.

The second cam follower pins2engage with the first straight grooves4formed at the moving cylinder10via the fixed cylinder30and the cam cylinder20. Specifically, the second cam follower pins2penetrate the fixed cylinder30and the cam cylinder20and engage with the first straight grooves4without abutting against and engaging with the fixed cylinder30and the cam cylinder20. In addition, in a case as shown inFIG.6, three second cam follower pins2are provided at equal intervals in the circumferential direction.

In addition, in the present embodiment, the third cam follower pin8is formed at the base frame9. The third cam follower pin8engages with the second straight groove32formed at the fixed cylinder30. In addition, the third cam follower pin8penetrates the fixed cylinder30and engages with the third cam groove26formed at the cam cylinder20. Accordingly, the third cam follower pin8is driven in the circumferential direction and the direction along the optical axis L and the second movement group is moved in a case where the cam cylinder20rotates around the optical axis L. Note that, as with the second cam follower pins2, three third cam follower pins8may be provided at equal intervals in the circumferential direction.

As described above, in the present embodiment, the first straight grooves4for guiding the first movement group straight are formed at the moving cylinder10included in the first movement group. In addition, the second cam follower pins2formed at the base frame9included in the second movement group penetrate the fixed cylinder30and the cam cylinder20and engage with the first straight grooves4. Therefore, restriction of rotation of the moving cylinder10is performed by means of the first straight groove4and the second cam follower pin2. Accordingly, a moving distance of the moving cylinder10in the direction along the optical axis L can be made large regardless of the length of the fixed cylinder30. In addition, according to the present embodiment, a cam cylinder and a linear movement cylinder do not need to be added to form a long straight groove, so that it is possible to make the number of components of the zoom lens device1small.

Furthermore, in the present embodiment, movement of the second movement group in the direction along the optical axis L is performed in a case where the third cam follower pin8separated from the second cam follower pins2is driven. Accordingly, a function for movement in the magnification change operation can be distributed to the second cam follower pins2and the third cam follower pin8.

<Example of Cam Follower Pin>

Next, a specific example of the above-described second cam follower pin2will be described. Regarding the above-described the second cam follower pin2, various forms can be adopted as long as the second cam follower pin2can engage with the first straight groove4and restrict rotation of the moving cylinder10. Hereinafter, a specific example of the second cam follower pin2will be described with reference toFIG.8.

FIG.8is a view showing one of specific examples of the second cam follower pin2.

The second cam follower pin2is composed of a screw2aand a pin shaft portion2b. The pin shaft portion2bhas a hollow columnar shape and includes a hollow portion2cextending along an axis. The hollow portion2cfunctions as an insertion portion for the screw2ain a case where the screw2ais attached to the base frame9. An upper portion of the pin shaft portion2babuts against the first straight groove4of the moving cylinder10and slides on the first straight groove4in a case where the moving cylinder10moves. Therefore, the pin shaft portion2bis formed of a material that is slidable with respect to the first straight groove4. The second cam follower pin2slides on the first straight groove4so that rotation of the moving cylinder10is restricted. Accordingly, the second cam follower pin2guides the first movement group straight, the first movement group including the moving cylinder10.

The following appendix will be disclosed in relation to the zoom lens device1described above.

In the related art, regarding a zoom lens device, a technique in which rotation of a zoom ring is restricted and a zoom locking operation is performed in a state where a lens is moved to a WIDE end for the purpose of improving convenience in carrying a zoom lens device is known.

In recent years, the angle of a cam groove has become sharper with reduction in diameter of a lens barrel. In addition, in the case of a design in which a feeding amount of a first movement group positioned closest to a subject side is large, the angle of the cam groove needs to be sharp. In a case where the angle of the cam groove is sharp as described above, a lens barrel is likely to fall because of the own weight thereof. Here, falling because of the own weight thereof means an unintentional magnification change operation performed because of the weight of a zoom lens device. In the case of an imaging operation performed by means of a lens barrel that is likely to fall because of the own weight thereof, there is a problem that the angle of view is unintentionally changed because of the influence of the posture of a lens and the ambient temperature of the lens at the time of the imaging operation even after a photographer determines the angle of view.

The technology disclosed below has been made in view of such circumstances and an object thereof is to provide a locking mechanism of a zoom lens device, a zoom lens device, and an optical device of which an object is to prevent falling because of the own weight thereof by performing a zoom locking operation at any magnification.

The following aspects (means) are disclosed for achievement of the above-described object.

According to a first aspect, there is provided a locking mechanism for a zoom lens device according to a first aspect including:a lock ring that is provided adjacent to a zoom ring and that is moved in an optical axis direction by being rotationally operated, the zoom ring rotating a cam cylinder of the zoom lens device;a linear movement ring that engages with the lock ring and that moves only in the optical axis direction as the lock ring moves in the optical axis direction; anda stopper that is fixed to the linear movement ring, that abuts against the zoom ring or a rotary member rotating together with the zoom ring, and that is formed of an elastic body,in which the linear movement ring moves in a direction toward the zoom ring and the stopper abuts against the zoom ring or the rotary member so that the zoom ring is fixed in a case where the lock ring is rotationally operated in a lock direction.

According to a second aspect, in the locking mechanism related to the first aspect, the stopper is preferably formed of rubber.

According to a third aspect, in the locking mechanism related to the first aspect or the second aspect, the stopper in the first aspect has a plate-like shape.

According to a fourth aspect, in the locking mechanism related to any one of the first to third aspects, the stopper abuts against the zoom ring or a shoulder-shaped abutting portion of the rotary member.

According to a fifth aspect, in the locking mechanism related to any one of the first to fourth aspects,the lock ring includes a cam cylinder that includes a cam groove engaging with a fixed pin and that engages with the linear movement ring,the cam cylinder is rotationally interlocked with the lock ring and moves together with the lock ring in the optical axis direction, andthe linear movement ring moves as the cam cylinder moves.

According to a sixth aspect, there is provided a zoom lens device including the locking mechanism for a zoom lens device related to any one of the first to fifth aspects,

According to a seventh aspect, there is provided an optical device including the zoom lens device related to the sixth aspect. Here, examples of the optical device include a binocle, a microscope, an interchangeable lens camera, and an integrated-lens camera.

[Overall Configuration of Lens Barrel]

Here, a case where the present disclosed technology is applied to an interchangeable lens of an interchangeable lens camera will be described as an example.

FIG.9is a cross-sectional view showing a schematic internal configuration of an interchangeable lens of the present embodiment.

An interchangeable lens101(corresponding to the zoom lens device1described above) shown in the drawing is an interchangeable lens for a digital still camera including a focus mechanism, a zoom mechanism, and an optical image stabilizer (OIS). The interchangeable lens101is attachably and detachably mounted to a camera body (not shown) via a mount102provided at a proximal end portion.

As shown inFIG.9, a lens barrel110of the interchangeable lens101of the present embodiment includes a first fixed cylinder112, a cam cylinder114, a moving cylinder116, and a second fixed cylinder118arranged in this order from an inner side.

The first fixed cylinder112and the second fixed cylinder118are fixed members with respect to the mount102. Both of the first fixed cylinder112and the second fixed cylinder118are fixed to a base member111on a proximal end portion side (an image side). The mount102is integrally attached to the base member111.

The cam cylinder114is a member that rotates around the first fixed cylinder112in a circumferential direction. The cam cylinder114is rotated in a case where a zoom ring103is rotationally operated. That is, the cam cylinder114is manually rotated. The zoom ring103is provided outside the second fixed cylinder118and is connected to the cam cylinder114via a connecting member (not shown). Note that, in addition to the zoom ring103, a lock ring120, a focus ring104, a stop ring105, and the like are provided outside the second fixed cylinder118. Note that a zoom locking mechanism including the lock ring120will be described later.

The moving cylinder116is a member that moves at an inner peripheral portion of the second fixed cylinder118along the optical axis L. In a case where the cam cylinder114is rotated, the moving cylinder116is moved forward and backward along the optical axis L by a cam mechanism (not shown).

Inside the lens barrel110, a first lens group G1, a second lens group G2, a third lens group G3, a fourth lens group G4, a fifth lens group G5, a sixth lens group G6, and a seventh lens group G7are provided in this order from an object side (the left side inFIG.9) along the optical axis L. A stop is provided between the second lens group G2and the third lens group G3. Each lens group is composed of at least one lens. The first lens group G1to the sixth lens group G6are lens groups that move in the case of zooming. The seventh lens group G7is a lens group fixed in the case of zooming.

The first lens group G1is held by a first lens group holding frame123. The first lens group holding frame123is held by being fixed to a distal end of the moving cylinder116. Therefore, the first lens group holding frame123is moved as the moving cylinder116moves.

The second lens group G2is a lens group that constitutes a shake-correction lens. The second lens group G2is held by a movable frame125. The movable frame125is held to be movable in a plane orthogonal to the optical axis L with respect to a base frame126. The base frame126is held to be movable along the optical axis L inside the first fixed cylinder112. In a case where the cam cylinder114is rotated, the base frame126is moved forward and backward along the optical axis L by a cam mechanism (not shown).

The third lens group G3to the sixth lens group G6are held by a moving lens frame128. The moving lens frame128is held to be movable along the optical axis L inside the first fixed cylinder112. In a case where the cam cylinder114is rotated, the moving lens frame128is moved forward and backward along the optical axis L by a cam mechanism (not shown).

Here, the third lens group G3, the fourth lens group G4, and the sixth lens group G6are held by being fixed to the moving lens frame128.

Meanwhile, the fifth lens group G5is held to be movable along the optical axis L with respect to the moving lens frame128. The fifth lens group G5is a lens group that constitutes a focus lens and focus adjustment is performed by moving the fifth lens group G5forward and backward along the optical axis L. The fifth lens group G5is held by a focus lens frame130and supported to be movable along the optical axis L. In addition, the fifth lens group G5is moved by being driven by an actuator provided at the moving lens frame128.

The seventh lens group G7is held by a seventh lens group holding frame132. The seventh lens group holding frame132is held by being fixed to a proximal end portion of the first fixed cylinder112.

Regarding a stop, a stop unit134including the drive mechanism therefor is integrally attached to a distal end portion of the moving lens frame128and is disposed at a predetermined position.

[Configuration of Zoom Locking Mechanism]

Next, the configuration of the zoom locking mechanism will be described.

The zoom locking mechanism is mainly composed of the lock ring120, a lock ring cam cylinder120A, a linear movement ring122, a sliding ring124, and the zoom ring103. Note that the lock ring cam cylinder120A may be a part of the lock ring120and the sliding ring124may be a part of the zoom ring103. That is, the lock ring cam cylinder120A and the lock ring120may be integrated with each other and the sliding ring124and the zoom ring103may be integrated with each other. The zoom locking mechanism is provided between the focus ring104and the stop ring105. In the zoom locking mechanism, a switch between a zoom locking operation and a zoom unlocking operation is performed in a case where the lock ring120(refer toFIG.9) is rotationally operated and is moved forward and backward along the optical axis L.

FIG.10is a view showing the configuration of the zoom locking mechanism provided between the focus ring104and the stop ring105of the lens barrel110described with reference toFIG.9. Note that the lock ring120and the zoom ring103, which are operation systems, are not shown for the purpose of showing the internal configuration.

The lock ring cam cylinder120A is provided inside the lock ring120(not shown inFIG.10). The lock ring cam cylinder120A is provided to be rotationally interlocked with the lock ring120. In addition, the lock ring cam cylinder120A rotates around the optical axis L together with the lock ring120rotating around the optical axis L. A cam groove121is formed at the lock ring cam cylinder120A and the cam groove121engages with a cam follower pin131formed at the second fixed cylinder118.

FIG.11is a geometry net of the lock ring cam cylinder120A.

The cam groove121of the lock ring cam cylinder120A is formed such that the lock ring cam cylinder120A moves in a direction (an arrow113) along the optical axis L in a case where the lock ring cam cylinder120A rotates around the optical axis L. The cam groove121is composed of a groove central portion P1, a groove end portion P2, and a groove end portion P3. The groove central portion P1is a groove for movement of the lock ring cam cylinder120A in a direction along the arrow113and is a straight groove that is inclined such that the lock ring cam cylinder120A moves in the direction along the arrow113as the lock ring cam cylinder120A rotates. The groove end portion P2and the groove end portion P3are grooves for fixation of the position of the lock ring cam cylinder120A in the case of the zoom locking operation or the zoom unlocking operation. Since the cam groove121of the lock ring cam cylinder120A is formed in such a manner, the zoom locking mechanism can be operated stably. Note that, although one cam groove121is shown inFIG.11, three cam grooves121may be disposed at equal intervals in the circumferential direction of the lock ring cam cylinder120A.

The linear movement ring122engages with the adjacent lock ring cam cylinder120A in the direction along the optical axis L (refer toFIGS.12and13). In addition, the linear movement ring122includes a straight groove117. The straight groove117engages with a cam follower pin119fixed to the second fixed cylinder118, so that the linear movement ring122is restricted from rotating around the optical axis L. Therefore, the linear movement ring122is restricted from rotating around the optical axis L and moves forward and backward in the direction along the optical axis L as the lock ring cam cylinder120A moves in the same direction. Further, stoppers S are fixed to the linear movement ring122(refer toFIG.13). Each stopper S is formed of an elastic body and has a plate-like shape. For example, the stoppers S are plate-shaped members formed of rubber, and a set of two stoppers S is provided at each of three positions in a circumferential direction of the linear movement ring122at equal intervals. The number of stoppers S is not particularly limited and may be one as long as the rotation of the sliding ring124can be restricted. An end portion of each stopper S includes a mount portion SA with respect to the linear movement ring122. In addition, an end portion of each stopper S that is opposite to the mount portion SA includes a protruding portion SB protruding from an end portion of the linear movement ring122. The protruding portion SB abuts against an abutting portion124A of the sliding ring124. A switch between the zoom locking operation and the zoom unlocking operation is performed based on an abutting state of the protruding portion SB and the abutting portion124A. Note that an abutting state of the mount portion SA and the abutting portion124A in the case of the zoom locking operation and the zoom unlocking operation will be described later.

The sliding ring124is provided inside the zoom ring103(not shown inFIG.10). The sliding ring124is rotationally interlocked with the zoom ring103and is a rotary member of the zoom ring103. The sliding ring124is connected to the cam cylinder114by a connecting member (not shown). In addition, in a case where the sliding ring124rotates around the optical axis L, the cam cylinder114also rotates and thus a magnification change operation is performed. Note that, in the present example, the zoom ring103and the sliding ring124are formed separately from each other. However, the zoom ring103and the sliding ring124may be integrally formed with each other. That is, the abutting portion124A that abuts against the stoppers S may be formed on a part of the zoom ring103.

Next, the way in which each part of the zoom locking mechanism is operated in a case where the zoom locking operation is performed will be described with reference toFIGS.12and13.

First, the state of the zoom locking mechanism in the case of the zoom unlocking operation will be described with reference toFIG.12.FIG.12is a cross-sectional view showing the state of the zoom locking mechanism in the case of the zoom unlocking operation.

In the case of the zoom unlocking operation, the lock ring120is positioned on the focus ring104side. In addition, the lock ring cam cylinder120A that is rotationally interlocked with the lock ring120and the linear movement ring122that engages with the lock ring cam cylinder120A in the direction along the optical axis L are also positioned on the focus ring104side. A gap a is provided between the linear movement ring122and the sliding ring124. The protruding portions SB of the stoppers S provided at the linear movement ring122abut against the abutting portion124A of the sliding ring124. In this case, the protruding portions SB simply abut against the abutting portion124A without being crushed between the linear movement ring122and the sliding ring124. Therefore, the protruding portions SB and the abutting portion124A slide on each other. Accordingly, it is possible to perform any magnification change operation by operating the zoom ring103since rotation of the sliding ring124in the circumferential direction is not restricted. Note that, various shapes are adopted for the abutting portion124A of the sliding ring124. For example, as shown inFIG.12, the abutting portion124A is formed in a shoulder-like shape.

As described above, in the case of the zoom unlocking operation, the lock ring120is positioned on the focus ring104side. Accordingly, the protruding portions SB of the stoppers S simply abut against the abutting portion124A without being crushed between the linear movement ring122and the sliding ring124, rotation of the sliding ring124in the circumferential direction is not restricted, and the zoom ring103can be operated in any manner.

Next, the state of the zoom locking mechanism in the case of the zoom locking operation will be described with reference toFIG.13.FIG.13is a cross-sectional view showing the state of the zoom locking mechanism in the case of the zoom locking operation.

In a case where the zoom locking operation is performed, the lock ring120is positioned on the zoom ring103side. In addition, the lock ring cam cylinder120A that is rotationally interlocked with the lock ring120and the linear movement ring122that engages with the lock ring cam cylinder120A in the direction along the optical axis L are also positioned on the zoom ring103side. In this case, the linear movement ring122and the sliding ring124are made close to each other, and there is no gap a therebetween (the gap a is made small). The protruding portions SB of the stoppers S provided at the linear movement ring122abut against the abutting portion124A of the sliding ring124and are crushed between the linear movement ring122and the sliding ring124. This is because, for example, movement of the sliding ring124in the direction along the optical axis L is restricted by a fixation pin (not shown) and the protruding portions SB are interposed between the linear movement ring122pressed toward the sliding ring124side along the optical axis L and the abutting portion124A. In addition, since the protruding portions SB are crushed, the protruding portions SB and the abutting portion124A are restricted from sliding on each other and the sliding ring124(the zoom ring103) is restricted from rotating. Accordingly, the sliding ring124(the zoom ring103) does not rotate freely and the zoom locking operation is performed.

As described above, in a case where the zoom locking operation is performed, the lock ring120is positioned on the zoom ring103side. Accordingly, the protruding portions SB of the stoppers S are crushed between the linear movement ring122and the sliding ring124and the protruding portions SB and the abutting portion124A are restricted from sliding on each other, so that the zoom locking operation is performed. Note that, since the zoom locking mechanism is provided separately from a zoom mechanism that performs the magnification change operation, the magnification change operation is not performed in a case where the zoom locking operation is performed. Therefore, a user can perform the zoom locking operation with the zoom ring103at any position (at any focal length). Specifically, the user can perform the zoom locking operation by operating the lock ring120with the zoom ring103positioned at any position.

Next, the way in which the lock ring120is operated in a case where the zoom unlocking operation and the zoom locking operation are performed will be described.

FIGS.14to16are views for description about a rotary operation of the lock ring120and are views showing the appearance of the lens barrel110.

FIG.14is a view showing the position of the lock ring120in the case of the zoom unlocking operation,FIG.15is a view showing the way in which the lock ring120is operated in a case where the zoom locking operation is performed, andFIG.16is a view showing the position of the lock ring120in the case of the zoom locking operation.

As shown inFIG.14, the lock ring120is positioned on the focus ring104side in the case of the zoom unlocking operation. Specifically, the lock ring120is positioned adjacent to the focus ring104. In addition, in the case of the zoom unlocking operation, the gap a is provided between the lock ring120and the zoom ring103.

As shown inFIG.15, in a case where the zoom locking operation is to be performed, the lock ring120is rotated around the optical axis L as represented by an arrow in the drawing. Note that the rotation direction of the lock ring120and forward and backward movement along the optical axis L are appropriately designed. The lock ring120moves in the direction along the optical axis L (toward a proximal end side of the lens barrel110) as the lock ring120rotates around the optical axis L.

In a case where the lock ring120is operated as described with reference toFIG.15, the lock ring120is positioned adjacent to the zoom ring103in the case of the zoom locking operation as shown inFIG.16. In a case where the lock ring120is positioned adjacent to the zoom ring103in this manner, the protruding portions SB of the stoppers S and the abutting portion124A of the sliding ring124are restricted from sliding on each other as described above and the zoom locking operation is performed.

As described above, according to the zoom locking mechanism, the sliding ring124is restricted from rotating around the optical axis L by the protruding portions SB of the stoppers S and the zoom locking operation is performed. Accordingly, in the case of the zoom lens device including the zoom locking mechanism, falling because of the own weight thereof can be suppressed. In addition, according to the present zoom locking mechanism, the sliding ring124can be restricted from rotating with the sliding ring124at any position other than a wide angle end or a telephoto end. In addition, according to the zoom locking mechanism, since the zoom locking mechanism is provided separately from a zoom mechanism that performs the magnification change operation, the magnification change operation is not performed in a case where the zoom locking operation is performed.

Although examples of the present invention have been described above, it is needless to say that the present invention is not limited to the above-described embodiments and various modifications can be made without departing from the spirit of the present invention.

EXPLANATION OF REFERENCES

1: zoom lens device

2: second cam follower pin

3: first cam follower pin

4: first straight groove

5: focus unit

6: fixation cam follower pin

7: first lens holding portion

8: third cam follower pin

9: base frame

9A: second lens holding portion

9B: third lens holding portion

10: moving cylinder

11: proximal end portion lens holding portion

22: first cam groove

24: second cam groove

26: third cam groove

30: fixed cylinder

32: second straight groove

40: base member