Patent Publication Number: US-2023152555-A1

Title: Zoom lens device and optical device

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application is a Continuation of PCT International Application No. PCT/JP2021/027446 filed on Jul. 26, 2021 claiming priority under 35 U.S.c §119(a) to Japanese Patent Application No. 2020-130635 filed on Jul. 31, 2020. Each of the above applications is hereby expressly incorporated by reference, in its entirety, into the present application. 
    
    
     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. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a cross-sectional view of a main part of a zoom lens device in the case of a magnification change operation. 
         FIG.  2    is a cross-sectional views of the main part of the zoom lens device in the case of the magnification change operation. 
         FIG.  3    is a perspective view of the main part moving in the case of the magnification change operation of the zoom lens device. 
         FIG.  4    is a perspective sectional view showing a second cam follower pin. 
         FIG.  5    is a view showing a second straight groove provided at a fixed cylinder and the second cam follower pin engaging with the second straight groove. 
         FIG.  6    is a perspective sectional view showing the second cam follower pins and a third cam follower pin. 
         FIG.  7    is a perspective sectional view showing the second cam follower pin. 
         FIG.  8    is a view showing one of specific examples of the second cam follower pin. 
         FIG.  9    is a cross-sectional view showing a schematic internal configuration of an interchangeable lens. 
         FIG.  10    is a view showing the configuration of a zoom locking mechanism. 
         FIG.  11    is a geometry net of a lock ring cam cylinder. 
         FIG.  12    is a cross-sectional view showing the state of the zoom locking mechanism in the case of a zoom unlocking operation. 
         FIG.  13    is a cross-sectional view showing the state of the zoom locking mechanism in the case of a zoom locking operation. 
         FIG.  14    is a view showing the position of a lock ring in the case of the zoom unlocking operation. 
         FIG.  15    is a view showing the way in which the lock ring is operated in a case where the zoom locking operation is performed. 
         FIG.  16    is a view showing the position of the lock ring in the case of the zoom locking operation. 
     
    
    
     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 to  FIGS.  1  to  3   . 
       FIG.  1    and  FIG.  2    are cross-sectional views of a main part of the zoom lens device in the case of a magnification change operation. 
       FIG.  1    is a cross-sectional view of a zoom lens device  1  in a telephoto end state and  FIG.  2    is a cross-sectional view of the zoom lens device  1  in a wide angle end state.  FIG.  3    is 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 device  1 . Note that, an optical axis L of lens groups of the zoom lens device  1  is shown in  FIGS.  1  to  3   . In addition, in  FIGS.  1  to  3   , a part of the zoom lens device  1  that is directly related to the present embodiment is shown and the other portions are not shown. For example, in  FIG.  1    and  FIG.  2   , a stop and the like are not shown. 
     The zoom lens device  1  includes a moving cylinder  10 , a cam cylinder  20 , and a fixed cylinder  30  arranged in this order from the outside. 
     The moving cylinder  10  includes a first lens holding portion  7 , a first lens group H 1 , a first cam follower pin  3 , and a first straight groove  4 . Here, the moving cylinder  10 , the first lens holding portion  7 , the first lens group H 1 , the first cam follower pin  3 , and the first straight groove  4  constitute a first movement group that integrally moves in a direction along the optical axis L. 
     The moving cylinder  10  is positioned outside the cam cylinder  20  and includes the first lens holding portion  7  provided on a distal end side, which is a subject side. The first lens holding portion  7  holds the first lens group H 1 . The moving cylinder  10  includes the first cam follower pin  3  provided on a rear end side. The first cam follower pin  3  protrudes from an inner peripheral surface of the moving cylinder  10  and engages with a first cam groove  22  (refer to  FIG.  3   ) of the cam cylinder  20 . Note that, as described above, in the related art, the first cam follower pin  3  also engages with a straight groove formed at the fixed cylinder  30  so that restriction of rotation of the first movement group is performed. However, the first cam follower pin  3  of the present embodiment engages only with the first cam groove  22  of the cam cylinder  20  and a straight groove for the first movement group is not formed at the fixed cylinder  30 . 
     At the inner peripheral surface of the moving cylinder  10 , the first straight groove  4  for the first movement group, which does not penetrate the inner peripheral surface, is formed. The first straight groove  4  is formed to extend in a linear shape connecting a proximal end portion side and a distal end portion side of the moving cylinder  10  in the direction along the optical axis L. The first straight groove  4  has, for example, a recessed shape and engages with a second cam follower pin  2  that has a protruding shape. In a case where the first movement group including the moving cylinder  10  moves, the moving cylinder  10  moves in the direction along the optical axis L with the second cam follower pin  2  abutting against and sliding on the first straight groove  4 . Note that, one or more first cam follower pins  3  and one or more first straight grooves  4  may be provided in a circumferential direction of the moving cylinder  10  and it is preferable that three first cam follower pins  3  and three first straight grooves  4  are formed at equal intervals in the circumferential direction. In addition, the number of second cam follower pins  2  formed is the same as the number of first straight grooves  4  formed. 
     The moving cylinder  10  moves in the direction along the optical axis L with the cam cylinder  20  rotating around the optical axis L. Specifically, the first cam follower pin  3  formed at the moving cylinder  10  engages with the first cam groove  22  ( FIG.  3   ) of the cam cylinder  20 . Therefore, in a case where the cam cylinder  20  rotates, the first cam follower pin  3  is driven and the moving cylinder  10  moves 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 cylinder  10  with the first cam follower pin  3  being driven. However, since the first straight groove  4  engages with the second cam follower pin  2 , rotation of the moving cylinder  10  is restricted and the moving cylinder  10  is guided straight. 
     The cam cylinder  20  includes at least the first cam groove  22 , a second cam groove  24 , and a third cam groove  26  (refer to  FIG.  3    (note that, the third cam groove  26  is not shown in  FIG.  3   )). The first cam groove  22  engages with the first cam follower pin  3  formed at the moving cylinder  10 . The second cam groove  24  engages with a fixation cam follower pin  6  (a fourth cam follower pin) formed at the fixed cylinder  30 . The third cam groove  26  engages with the second cam follower pin  2  formed at a base frame  9 . 
     The cam cylinder  20  rotates around the optical axis L. In a case where the cam cylinder  20  rotates, the first cam follower pin  3  engaging with the first cam groove  22  is guided in the direction along the optical axis L and the circumferential direction. In addition, in a case where the cam cylinder  20  rotates, the cam cylinder  20  is guided with respect to the fixed cylinder  30  in the direction along the optical axis L and the circumferential direction because of the action of the fixation cam follower pin  6  and the second cam groove  24  engaging with each other. 
     The fixed cylinder  30  includes the base frame  9 , a focus unit  5 , a proximal end portion lens holding portion  11 , and the fixation cam follower pin  6 . The base frame  9  includes a second lens holding portion  9 A, a third lens holding portion  9 B, and the second cam follower pin  2 . The base frame  9 , the second lens holding portion  9 A, the third lens holding portion  9 B, and the second cam follower pin  2  constitute a second movement group. The second lens holding portion  9 A holds a second lens group H 2  and the third lens holding portion  9 B holds a third lens group H 3 . In addition, the second cam follower pin  2  that engages with the first straight groove  4  is formed on a distal end side of the base frame  9 . 
     The focus unit  5  includes 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 unit  5  will be omitted. 
     The proximal end portion lens holding portion  11  includes a proximal end portion lens group H 4 . In addition, a proximal end side of the fixed cylinder  30  is fixed by a base member  40 . A mount (not shown) is integrally attached to the base member  40  and is attached to a main body (the optical device). Note that the zoom lens device  1  can be attached to various optical devices. For example, examples of the optical device to which the zoom lens device  1  is attached include a binocle, a microscope, an interchangeable lens camera, and an integrated-lens camera. 
     The fixation cam follower pin  6  is formed to protrude from the fixed cylinder  30  and engages with the second cam groove  24  formed at the cam cylinder  20 . In a case where the cam cylinder  20  rotates around the optical axis L, the cam cylinder  20  moves forward and backward with respect to the fixed cylinder  30  along the optical axis L. 
     Next, the second cam follower pin  2  of the present embodiment will be described with reference to  FIGS.  4  and  5   .  FIG.  4    is a perspective sectional view showing the second cam follower pin  2  of the present embodiment. In addition,  FIG.  5    is a view showing a second straight groove  32  provided at the fixed cylinder  30  and the second cam follower pin  2  engaging with the second straight groove  32 . 
     The second cam follower pin  2  of the present embodiment penetrates the fixed cylinder  30  and the cam cylinder  20 . Specifically, the second cam follower pin  2  engages with and penetrates the second straight groove  32  for the second movement group that is provided at the fixed cylinder  30  and the second cam follower pin  2  engages with and penetrates the third cam groove  26  provided at the cam cylinder  20 . In addition, the second cam follower pin  2  penetrating the cam cylinder  20  engages with the first straight groove  4  formed at the moving cylinder  10 . 
     The second cam follower pin  2  engages with the first straight groove  4 , restricts rotation of the moving cylinder  10 , and guides the moving cylinder  10  straight along the optical axis L. 
     In addition, since the second cam follower pin  2  engages with the third cam groove  26  formed at the cam cylinder  20  and engages with the second straight groove  32  formed at the fixed cylinder  30 , the second cam follower pin  2  is driven along the optical axis L in a case where the cam cylinder  20  rotates around the optical axis L. Accordingly, the second movement group including the base frame  9  moves along the optical axis L. 
     As described above, in the present embodiment, the first straight groove  4  for guiding the first movement group straight is formed at the moving cylinder  10  included in the first movement group. In addition, the second cam follower pin  2  formed at the base frame  9  included in the second movement group penetrates the fixed cylinder  30  and the cam cylinder  20  and engages with the first straight groove  4 . Therefore, restriction of rotation of the moving cylinder  10  is performed by means of the first straight groove  4  and the second cam follower pin  2 . Accordingly, a moving distance of the moving cylinder  10  in the direction along the optical axis L can be made large regardless of the length of the fixed cylinder  30 . 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 device  1  small. 
     Furthermore, in the present embodiment, the second cam follower pin  2  engages with the first straight groove  4 , engages with the second straight groove  32  formed at the fixed cylinder  30 , and engages with the third cam groove  26  formed at the cam cylinder  20 . Therefore, the second cam follower pin  2  guides the moving cylinder  10  straight 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 device  1  small in comparison with a case where a cam follower pin that engages with the first straight groove  4  and a cam follower pin that engages with the third cam groove  26  and the second straight groove  32  are formed. 
     Second Embodiment 
     Next, a second embodiment will be described. In the present embodiment, as with the first embodiment, the second cam follower pin  2  guides the moving cylinder  10  straight. Furthermore, in the present embodiment, a third cam follower pin  8  is formed and the third cam follower pin  8  guides the second movement group straight. 
     Next, the second cam follower pin  2  and the third cam follower pin  8  of the present embodiment will be described with reference to  FIGS.  6  and  7   .  FIG.  6    is a perspective sectional view showing the second cam follower pins  2  and the third cam follower pin  8 . Note that, in  FIG.  6   , the first cam groove  22  with which the first cam follower pin  3  engages is not shown.  FIG.  7    is a perspective sectional view showing the second cam follower pin  2 . Note that, in  FIG.  7   , the second lens holding portion  9 A is not shown. 
     The second cam follower pins  2  and the third cam follower pin  8  are formed at the base frame  9 . 
     The second cam follower pins  2  engage with the first straight grooves  4  formed at the moving cylinder  10  via the fixed cylinder  30  and the cam cylinder  20 . Specifically, the second cam follower pins  2  penetrate the fixed cylinder  30  and the cam cylinder  20  and engage with the first straight grooves  4  without abutting against and engaging with the fixed cylinder  30  and the cam cylinder  20 . In addition, in a case as shown in  FIG.  6   , three second cam follower pins  2  are provided at equal intervals in the circumferential direction. 
     In addition, in the present embodiment, the third cam follower pin  8  is formed at the base frame  9 . The third cam follower pin  8  engages with the second straight groove  32  formed at the fixed cylinder  30 . In addition, the third cam follower pin  8  penetrates the fixed cylinder  30  and engages with the third cam groove  26  formed at the cam cylinder  20 . Accordingly, the third cam follower pin  8  is 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 cylinder  20  rotates around the optical axis L. Note that, as with the second cam follower pins  2 , three third cam follower pins  8  may be provided at equal intervals in the circumferential direction. 
     As described above, in the present embodiment, the first straight grooves  4  for guiding the first movement group straight are formed at the moving cylinder  10  included in the first movement group. In addition, the second cam follower pins  2  formed at the base frame  9  included in the second movement group penetrate the fixed cylinder  30  and the cam cylinder  20  and engage with the first straight grooves  4 . Therefore, restriction of rotation of the moving cylinder  10  is performed by means of the first straight groove  4  and the second cam follower pin  2 . Accordingly, a moving distance of the moving cylinder  10  in the direction along the optical axis L can be made large regardless of the length of the fixed cylinder  30 . 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 device  1  small. 
     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 pin  8  separated from the second cam follower pins  2  is driven. Accordingly, a function for movement in the magnification change operation can be distributed to the second cam follower pins  2  and the third cam follower pin  8 . 
     &lt;Example of Cam Follower Pin&gt; 
     Next, a specific example of the above-described second cam follower pin  2  will be described. Regarding the above-described the second cam follower pin  2 , various forms can be adopted as long as the second cam follower pin  2  can engage with the first straight groove  4  and restrict rotation of the moving cylinder  10 . Hereinafter, a specific example of the second cam follower pin  2  will be described with reference to  FIG.  8   . 
       FIG.  8    is a view showing one of specific examples of the second cam follower pin  2 . 
     The second cam follower pin  2  is composed of a screw  2   a  and a pin shaft portion  2   b . The pin shaft portion  2   b  has a hollow columnar shape and includes a hollow portion  2   c  extending along an axis. The hollow portion  2   c  functions as an insertion portion for the screw  2   a  in a case where the screw  2   a  is attached to the base frame  9 . An upper portion of the pin shaft portion  2   b  abuts against the first straight groove  4  of the moving cylinder  10  and slides on the first straight groove  4  in a case where the moving cylinder  10  moves. Therefore, the pin shaft portion  2   b  is formed of a material that is slidable with respect to the first straight groove  4 . The second cam follower pin  2  slides on the first straight groove  4  so that rotation of the moving cylinder  10  is restricted. Accordingly, the second cam follower pin  2  guides the first movement group straight, the first movement group including the moving cylinder  10 . 
     &lt;Appendix&gt; 
     The following appendix will be disclosed in relation to the zoom lens device  1  described 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; and   a 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, and   the 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.  9    is a cross-sectional view showing a schematic internal configuration of an interchangeable lens of the present embodiment. 
     An interchangeable lens  101  (corresponding to the zoom lens device  1  described 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 lens  101  is attachably and detachably mounted to a camera body (not shown) via a mount  102  provided at a proximal end portion. 
     As shown in  FIG.  9   , a lens barrel  110  of the interchangeable lens  101  of the present embodiment includes a first fixed cylinder  112 , a cam cylinder  114 , a moving cylinder  116 , and a second fixed cylinder  118  arranged in this order from an inner side. 
     The first fixed cylinder  112  and the second fixed cylinder  118  are fixed members with respect to the mount  102 . Both of the first fixed cylinder  112  and the second fixed cylinder  118  are fixed to a base member  111  on a proximal end portion side (an image side). The mount  102  is integrally attached to the base member  111 . 
     The cam cylinder  114  is a member that rotates around the first fixed cylinder  112  in a circumferential direction. The cam cylinder  114  is rotated in a case where a zoom ring  103  is rotationally operated. That is, the cam cylinder  114  is manually rotated. The zoom ring  103  is provided outside the second fixed cylinder  118  and is connected to the cam cylinder  114  via a connecting member (not shown). Note that, in addition to the zoom ring  103 , a lock ring  120 , a focus ring  104 , a stop ring  105 , and the like are provided outside the second fixed cylinder  118 . Note that a zoom locking mechanism including the lock ring  120  will be described later. 
     The moving cylinder  116  is a member that moves at an inner peripheral portion of the second fixed cylinder  118  along the optical axis L. In a case where the cam cylinder  114  is rotated, the moving cylinder  116  is moved forward and backward along the optical axis L by a cam mechanism (not shown). 
     Inside the lens barrel  110 , a first lens group G 1 , a second lens group G 2 , a third lens group G 3 , a fourth lens group G 4 , a fifth lens group G 5 , a sixth lens group G 6 , and a seventh lens group G 7  are provided in this order from an object side (the left side in  FIG.  9   ) along the optical axis L. A stop is provided between the second lens group G 2  and the third lens group G 3 . Each lens group is composed of at least one lens. The first lens group G 1  to the sixth lens group G 6  are lens groups that move in the case of zooming. The seventh lens group G 7  is a lens group fixed in the case of zooming. 
     The first lens group G 1  is held by a first lens group holding frame  123 . The first lens group holding frame  123  is held by being fixed to a distal end of the moving cylinder  116 . Therefore, the first lens group holding frame  123  is moved as the moving cylinder  116  moves. 
     The second lens group G 2  is a lens group that constitutes a shake-correction lens. The second lens group G 2  is held by a movable frame  125 . The movable frame  125  is held to be movable in a plane orthogonal to the optical axis L with respect to a base frame  126 . The base frame  126  is held to be movable along the optical axis L inside the first fixed cylinder  112 . In a case where the cam cylinder  114  is rotated, the base frame  126  is moved forward and backward along the optical axis L by a cam mechanism (not shown). 
     The third lens group G 3  to the sixth lens group G 6  are held by a moving lens frame  128 . The moving lens frame  128  is held to be movable along the optical axis L inside the first fixed cylinder  112 . In a case where the cam cylinder  114  is rotated, the moving lens frame  128  is moved forward and backward along the optical axis L by a cam mechanism (not shown). 
     Here, the third lens group G 3 , the fourth lens group G 4 , and the sixth lens group G 6  are held by being fixed to the moving lens frame  128 . 
     Meanwhile, the fifth lens group G 5  is held to be movable along the optical axis L with respect to the moving lens frame  128 . The fifth lens group G 5  is a lens group that constitutes a focus lens and focus adjustment is performed by moving the fifth lens group G 5  forward and backward along the optical axis L. The fifth lens group G 5  is held by a focus lens frame  130  and supported to be movable along the optical axis L. In addition, the fifth lens group G 5  is moved by being driven by an actuator provided at the moving lens frame  128 . 
     The seventh lens group G 7  is held by a seventh lens group holding frame  132 . The seventh lens group holding frame  132  is held by being fixed to a proximal end portion of the first fixed cylinder  112 . 
     Regarding a stop, a stop unit  134  including the drive mechanism therefor is integrally attached to a distal end portion of the moving lens frame  128  and 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 ring  120 , a lock ring cam cylinder  120 A, a linear movement ring  122 , a sliding ring  124 , and the zoom ring  103 . Note that the lock ring cam cylinder  120 A may be a part of the lock ring  120  and the sliding ring  124  may be a part of the zoom ring  103 . That is, the lock ring cam cylinder  120 A and the lock ring  120  may be integrated with each other and the sliding ring  124  and the zoom ring  103  may be integrated with each other. The zoom locking mechanism is provided between the focus ring  104  and the stop ring  105 . 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 ring  120  (refer to  FIG.  9   ) is rotationally operated and is moved forward and backward along the optical axis L. 
       FIG.  10    is a view showing the configuration of the zoom locking mechanism provided between the focus ring  104  and the stop ring  105  of the lens barrel  110  described with reference to  FIG.  9   . Note that the lock ring  120  and the zoom ring  103 , which are operation systems, are not shown for the purpose of showing the internal configuration. 
     The lock ring cam cylinder  120 A is provided inside the lock ring  120  (not shown in  FIG.  10   ). The lock ring cam cylinder  120 A is provided to be rotationally interlocked with the lock ring  120 . In addition, the lock ring cam cylinder  120 A rotates around the optical axis L together with the lock ring  120  rotating around the optical axis L. A cam groove  121  is formed at the lock ring cam cylinder  120 A and the cam groove  121  engages with a cam follower pin  131  formed at the second fixed cylinder  118 . 
       FIG.  11    is a geometry net of the lock ring cam cylinder  120 A. 
     The cam groove  121  of the lock ring cam cylinder  120 A is formed such that the lock ring cam cylinder  120 A moves in a direction (an arrow  113 ) along the optical axis L in a case where the lock ring cam cylinder  120 A rotates around the optical axis L. The cam groove  121  is composed of a groove central portion P 1 , a groove end portion P 2 , and a groove end portion P 3 . The groove central portion P 1  is a groove for movement of the lock ring cam cylinder  120 A in a direction along the arrow  113  and is a straight groove that is inclined such that the lock ring cam cylinder  120 A moves in the direction along the arrow  113  as the lock ring cam cylinder  120 A rotates. The groove end portion P 2  and the groove end portion P 3  are grooves for fixation of the position of the lock ring cam cylinder  120 A in the case of the zoom locking operation or the zoom unlocking operation. Since the cam groove  121  of the lock ring cam cylinder  120 A is formed in such a manner, the zoom locking mechanism can be operated stably. Note that, although one cam groove  121  is shown in  FIG.  11   , three cam grooves  121  may be disposed at equal intervals in the circumferential direction of the lock ring cam cylinder  120 A. 
     The linear movement ring  122  engages with the adjacent lock ring cam cylinder  120 A in the direction along the optical axis L (refer to  FIGS.  12  and  13   ). In addition, the linear movement ring  122  includes a straight groove  117 . The straight groove  117  engages with a cam follower pin  119  fixed to the second fixed cylinder  118 , so that the linear movement ring  122  is restricted from rotating around the optical axis L. Therefore, the linear movement ring  122  is 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 cylinder  120 A moves in the same direction. Further, stoppers S are fixed to the linear movement ring  122  (refer to  FIG.  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 ring  122  at equal intervals. The number of stoppers S is not particularly limited and may be one as long as the rotation of the sliding ring  124  can be restricted. An end portion of each stopper S includes a mount portion SA with respect to the linear movement ring  122 . 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 ring  122 . The protruding portion SB abuts against an abutting portion  124 A of the sliding ring  124 . 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 portion  124 A. Note that an abutting state of the mount portion SA and the abutting portion  124 A in the case of the zoom locking operation and the zoom unlocking operation will be described later. 
     The sliding ring  124  is provided inside the zoom ring  103  (not shown in  FIG.  10   ). The sliding ring  124  is rotationally interlocked with the zoom ring  103  and is a rotary member of the zoom ring  103 . The sliding ring  124  is connected to the cam cylinder  114  by a connecting member (not shown). In addition, in a case where the sliding ring  124  rotates around the optical axis L, the cam cylinder  114  also rotates and thus a magnification change operation is performed. Note that, in the present example, the zoom ring  103  and the sliding ring  124  are formed separately from each other. However, the zoom ring  103  and the sliding ring  124  may be integrally formed with each other. That is, the abutting portion  124 A that abuts against the stoppers S may be formed on a part of the zoom ring  103 . 
     [Zoom Locking Operation] 
     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 to  FIGS.  12  and  13   . 
     First, the state of the zoom locking mechanism in the case of the zoom unlocking operation will be described with reference to  FIG.  12   .  FIG.  12    is 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 ring  120  is positioned on the focus ring  104  side. In addition, the lock ring cam cylinder  120 A that is rotationally interlocked with the lock ring  120  and the linear movement ring  122  that engages with the lock ring cam cylinder  120 A in the direction along the optical axis L are also positioned on the focus ring  104  side. A gap a is provided between the linear movement ring  122  and the sliding ring  124 . The protruding portions SB of the stoppers S provided at the linear movement ring  122  abut against the abutting portion  124 A of the sliding ring  124 . In this case, the protruding portions SB simply abut against the abutting portion  124 A without being crushed between the linear movement ring  122  and the sliding ring  124 . Therefore, the protruding portions SB and the abutting portion  124 A slide on each other. Accordingly, it is possible to perform any magnification change operation by operating the zoom ring  103  since rotation of the sliding ring  124  in the circumferential direction is not restricted. Note that, various shapes are adopted for the abutting portion  124 A of the sliding ring  124 . For example, as shown in  FIG.  12   , the abutting portion  124 A is formed in a shoulder-like shape. 
     As described above, in the case of the zoom unlocking operation, the lock ring  120  is positioned on the focus ring  104  side. Accordingly, the protruding portions SB of the stoppers S simply abut against the abutting portion  124 A without being crushed between the linear movement ring  122  and the sliding ring  124 , rotation of the sliding ring  124  in the circumferential direction is not restricted, and the zoom ring  103  can 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 to  FIG.  13   .  FIG.  13    is 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 ring  120  is positioned on the zoom ring  103  side. In addition, the lock ring cam cylinder  120 A that is rotationally interlocked with the lock ring  120  and the linear movement ring  122  that engages with the lock ring cam cylinder  120 A in the direction along the optical axis L are also positioned on the zoom ring  103  side. In this case, the linear movement ring  122  and the sliding ring  124  are 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 ring  122  abut against the abutting portion  124 A of the sliding ring  124  and are crushed between the linear movement ring  122  and the sliding ring  124 . This is because, for example, movement of the sliding ring  124  in 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 ring  122  pressed toward the sliding ring  124  side along the optical axis L and the abutting portion  124 A. In addition, since the protruding portions SB are crushed, the protruding portions SB and the abutting portion  124 A are restricted from sliding on each other and the sliding ring  124  (the zoom ring  103 ) is restricted from rotating. Accordingly, the sliding ring  124  (the zoom ring  103 ) 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 ring  120  is positioned on the zoom ring  103  side. Accordingly, the protruding portions SB of the stoppers S are crushed between the linear movement ring  122  and the sliding ring  124  and the protruding portions SB and the abutting portion  124 A 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 ring  103  at any position (at any focal length). Specifically, the user can perform the zoom locking operation by operating the lock ring  120  with the zoom ring  103  positioned at any position. 
     [Operation] 
     Next, the way in which the lock ring  120  is operated in a case where the zoom unlocking operation and the zoom locking operation are performed will be described. 
       FIGS.  14  to  16    are views for description about a rotary operation of the lock ring  120  and are views showing the appearance of the lens barrel  110 . 
       FIG.  14    is a view showing the position of the lock ring  120  in the case of the zoom unlocking operation,  FIG.  15    is a view showing the way in which the lock ring  120  is operated in a case where the zoom locking operation is performed, and  FIG.  16    is a view showing the position of the lock ring  120  in the case of the zoom locking operation. 
     As shown in  FIG.  14   , the lock ring  120  is positioned on the focus ring  104  side in the case of the zoom unlocking operation. Specifically, the lock ring  120  is positioned adjacent to the focus ring  104 . In addition, in the case of the zoom unlocking operation, the gap a is provided between the lock ring  120  and the zoom ring  103 . 
     As shown in  FIG.  15   , in a case where the zoom locking operation is to be performed, the lock ring  120  is rotated around the optical axis L as represented by an arrow in the drawing. Note that the rotation direction of the lock ring  120  and forward and backward movement along the optical axis L are appropriately designed. The lock ring  120  moves in the direction along the optical axis L (toward a proximal end side of the lens barrel  110 ) as the lock ring  120  rotates around the optical axis L. 
     In a case where the lock ring  120  is operated as described with reference to  FIG.  15   , the lock ring  120  is positioned adjacent to the zoom ring  103  in the case of the zoom locking operation as shown in  FIG.  16   . In a case where the lock ring  120  is positioned adjacent to the zoom ring  103  in this manner, the protruding portions SB of the stoppers S and the abutting portion  124 A of the sliding ring  124  are 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 ring  124  is 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 ring  124  can be restricted from rotating with the sliding ring  124  at 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 
       9 A: second lens holding portion 
       9 B: third lens holding portion 
       10 : moving cylinder 
       11 : proximal end portion lens holding portion 
       20 : cam cylinder 
       22 : first cam groove 
       24 : second cam groove 
       26 : third cam groove 
       30 : fixed cylinder 
       32 : second straight groove 
       40 : base member