JP2012203196A - Lens barrel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lens barrel in which a load applied on a cam cylinder during rotation is kept almost constant.SOLUTION: A lens barrel 25 includes a front lens unit 41, a rear lens unit 42, a supporting cylinder 43, and a cam cylinder 44. With the cam cylinder 44, a front cam hole 61, a rear cam hole 62, and a rotation regulation hole 66 are provided. The cam holes 61 and 62 are composed of first inclination parts 61a and 62a and second inclination parts 61b and 62b, respectively. The inclination angles of the second inclination parts 61b and 62b with respect to an optical axis direction are smaller than those of the first inclination parts 61a and 62a. The rotation regulation hole 66 is composed of a first regulation part 66a to which a regulation member 68 engages when zoom rollers 51 move along the first inclination parts 61a and 62a, and a second regulation part 66b to which the regulation member 68 engages when the zoom rollers 51 move along the second inclination parts 61b and 62b. The hole width of the first regulation part 66a is smaller than that of the second regulation part 66b. The regulation member 68 is provided to be elastically deformable, and deforms following the change of the hole width of the first and second regulation holes 66a and 66b.

Description

  The present invention relates to a lens barrel.

  A lens barrel used in various optical devices such as projectors and digital cameras is provided with a cam barrel for moving the lens in the optical axis direction and a support barrel for rotatably supporting the cam barrel. The lens is held by a lens frame, and this lens frame is arranged inside the cam barrel. An elongated cam hole for moving the lens frame is formed on the outer periphery of the cam cylinder, and a cam follower such as a roller or a shaft that engages with the cam hole is attached to the outer periphery of the lens frame. When the cam cylinder is rotated and the cam follower is moved along the cam hole, the lens frame moves in the optical axis direction, and the projection image and the captured image are zoomed by the movement of the lens frame.

  The cam hole is formed continuously with the first inclined portion having a large inclination angle with respect to the optical axis direction and a small movement amount for moving the lens frame during rotation, and the inclination angle with respect to the optical axis direction is the first inclination angle. Generally, it is composed of a second inclined portion that is smaller than one inclined portion and has a large movement amount for moving the lens frame during rotation. In the cam cylinder in which such a cam hole is formed, the load applied to the cam cylinder differs depending on whether the cam follower moves the first inclined portion or the second inclined portion. In the moving device and the optical member moving device described in Patent Literature 1, the contact frictional force between the cam cylinder and the cam follower is reduced by vibration, and the load applied to the cam cylinder is made constant, so that the cam cylinder is rotated with a constant rotational force. I can move.

JP 2005-316394 A

  In Patent Document 1, since the contact friction force between the cam cylinder and the cam follower is reduced by vibration, a vibration generator is required, which increases the number of parts and increases the cost. Furthermore, the lens frame may be displaced due to vibration.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a lens barrel capable of making the load applied to the cam barrel almost constant during rotation with a simple configuration.

  In order to solve the above problems, a lens barrel according to the present invention includes a lens frame that holds a lens, a cam follower provided in the lens frame, and a cam hole that engages with the cam follower. A cam cylinder that moves the frame in the optical axis direction, wherein a rotation limiting hole that limits a rotation range is formed, and the cam hole is inclined with respect to the optical axis direction, and the cam hole is in the optical axis direction. A cam cylinder composed of a second inclined part having an inclination angle smaller than that of the first inclined part and having a larger amount of movement for moving the lens frame than the first inclined part during rotation, and the cam cylinder can be rotated. And a support cylinder attached to the support cylinder and engaged with the rotation limiting hole, and the rotation limiting hole is formed when the cam follower moves the first inclined portion. The engagement member engages The limiting portion includes a second limiting portion that engages with the engaging member when the cam follower moves on the second inclined portion, and the first limiting portion includes the first inclined portion and the second inclined portion. The engagement member is provided so as to be elastically deformable in the hole width direction of the first restriction part and the second restriction part, according to the inclination angle of the second restriction part. The first limiting portion and the second limiting portion are deformed following the change in the hole width. In addition, polyacetal is mentioned as a raw material which comprises the said engagement member.

  Moreover, it is preferable that the engaging member is formed in a cylindrical shape, and is formed with a slit for making it deformable, or is formed in a deformable thin cylindrical shape.

  Furthermore, it is preferable that the first limiting portion and the second limiting portion are connected by an inclined surface so that the hole width changes smoothly.

  The lens barrel of the present invention includes a lens frame that holds a lens, a cam follower provided in the lens frame, and a cam hole that engages the cam follower, and the lens frame is moved in the optical axis direction by rotation. The cam cylinder includes a first inclined portion inclined with respect to the optical axis direction, and an inclination angle with respect to the optical axis direction is smaller than that of the first inclined portion, and the cam hole is rotated from the first inclined portion during rotation. And a support cylinder that rotatably supports the cam cylinder, and the first inclination part includes the first inclination part. The cam follower is formed to be narrower than the second inclined portion according to the inclination angle of the inclined portion and the second inclined portion, and the cam follower can be elastically deformed in the hole width direction of the first inclined portion and the second inclined portion. Of the first inclined portion and the second inclined portion. Characterized by deformed following the change in the width.

  Further, the cam follower is preferably formed in a cylindrical shape, and is formed with a slit for enabling deformation, or formed into a deformable thin cylindrical shape.

  Furthermore, it is preferable that the first inclined portion and the second inclined portion are connected by an inclined surface so that the hole width changes smoothly.

  A plurality of the lens frames are provided, and the cam cylinder is formed with a plurality of cam holes having different inclination angles with respect to an optical axis direction, and the lens frame has the largest inclination angle among the plurality of cam holes. One of the smallest movement amounts to move the first inclined portion is formed with a narrower hole width than the second inclined portion, and the other cam holes include the first inclined portion, the second inclined portion, and the like. Are formed with the same hole width, and one of the cam followers attached to each of the cam followers is engaged with a cam hole of which the hole width is changed, and is elastic following the change of the hole width of the cam hole. Preferably, the other cam followers are provided so as not to be deformed.

  Further, it is preferable that a rotation limiting hole for limiting a rotation range is formed in the cam cylinder, and an engagement member that engages with the rotation limiting hole is attached to the support cylinder.

  The cam cylinder is preferably rotated by a motor.

  According to the present invention, the first limiting portion of the limiting hole is formed narrower than the second limiting portion according to the inclination angles of the first inclined portion and the second inclined portion of the cam hole, and the engaging member is Since the first follower and the second restrictor are deformed following the change in the hole width, the load applied to the cam cylinder is made substantially the same when the cam follower moves between the first inclined part and the second inclined part. be able to. Thereby, when rotating a cam cylinder with a motor, the load concerning a motor becomes fixed and the drive sound of a motor can be made constant. Further, when the cam cylinder is manually rotated by the operator, the operation load applied to the operator when the cam cylinder is rotated becomes substantially constant, so that the operability can be improved.

It is a perspective view which shows a projector. It is explanatory drawing which shows the schematic structure of a projector. It is a perspective view which shows a lens-barrel. It is a perspective view which shows a support cylinder. It is a perspective view which shows a cam cylinder. It is a perspective view which shows a front lens unit. It is front sectional drawing which shows the lens-barrel before roller attachment. It is front sectional drawing which shows the lens barrel after roller attachment. It is a side view which shows a cam cylinder, a roller, and a restriction member when a restriction member is located in the 1st restriction part of a rotation restriction hole. It is a side view which shows a cam cylinder, a roller, and a restriction member when a restriction member is located in the 2nd restriction part of a rotation restriction hole. It is side surface sectional drawing which shows a support cylinder, a cam cylinder, and a restriction member when a restriction member is located in the 2nd restriction part of a rotation restriction hole. It is side surface sectional drawing which shows a support cylinder, a cam cylinder, and a restriction member when a restriction member is located in the 1st restriction part of a rotation restriction hole. It is a side view which shows a cam cylinder, a cam follower, a zoom roller, and a restriction | limiting roller when the cam follower of embodiment which made the 1st inclination part of the front cam hole narrower than the 2nd inclination part is located in a 1st inclination part. . It is a side view which shows a cam cylinder, a cam follower, a zoom roller, and a restriction | limiting roller when the cam follower of embodiment shown in FIG. 13 is located in a 2nd inclination part. It is a side view which shows the cam cylinder of the embodiment which provided the side hole in the both sides of the linear rotation restriction hole, the zoom roller, and the restriction roller.

  As shown in FIG. 1, when the projector 10 is used, the front projection lens 11 is exposed on the front surface of the case 14 by opening the lens cover. A rear projection lens 12 is disposed behind the front projection lens 11 in the case 14. A screen 15 (see FIG. 2) is disposed in front of the front projection lens 11, and an image is projected from the front projection lens 11. A rotary zoom dial 16 is provided on the upper surface of the case 14, and the zoom dial 16 is operated (rotated) in the A direction and the B direction in FIG. Zoom adjustment of the image projected on the screen 15 is performed.

  As shown in FIG. 2, a light source 21, an illumination optical system 22, a total reflection prism 23, a DMD 24, a lens barrel 25 that is a projection optical system, a zoom adjustment mechanism 26, and the like are provided inside the case 14. As the light source 21, for example, a white light source such as a xenon lamp or a mercury lamp is used. The illumination light emitted from the light source 21 enters the illumination optical system 22.

  The illumination optical system 22 includes a color wheel 31, a rod integrator 32, relay lenses 33 and 34, and a mirror 35. The color wheel 31 separates the illumination light from the light source 21 into B, G, and R colors in a time-sharing manner. The color wheel 31 has three color filters, a B filter that transmits only B light, a G filter that transmits only G light, and an R filter that transmits only R light, from the rotation center of the substrate. They are arranged at approximately the same distance. The color wheel 31 rotates at high speed and sequentially inserts the filters of each color into the illumination optical path. As a result, the illumination light is color-separated into three colors of B, G, and R in a time-sharing manner, and the separated light of each color is sequentially emitted toward the DMD 24.

  The rod integrator 32 is made of, for example, glass and has a reflection surface formed on the inner side. The light separated by the color wheel 31 is homogenized by repeating reflection while passing through the rod integrator 32. The relay lenses 33 and 34 relay the light beam emitted from the rod integrator 32 to the mirror 35. The mirror 35 reflects this light beam toward the total reflection prism 23.

  The total reflection prism 23 is composed of two triangular prisms, and an air gap is provided between the two triangular prisms to form the reflection surface 23a. The incident light incident on the total reflection prism 23 from the mirror 35 has a larger incident angle than the critical angle, and therefore is totally reflected by the reflection surface 23a and incident on the DMD 24. On the other hand, the reflected light reflected by the DMD 24 is transmitted through the reflecting surface 23a because the incident angle is smaller than the critical angle.

  As is well known, the DMD 24 has a large number of mirror elements corresponding to pixels arranged in a matrix on the light receiving surface. Each mirror element changes the reflection direction of the received illumination light by changing the angle based on the projected image. When displaying a pixel brightly, the mirror element is displaced to the ON position, and the received light is reflected toward the lens barrel 25 as ON light. On the other hand, when a pixel is displayed darkly, the mirror element is displaced to the off position, and the received light is reflected as off light in a direction away from the lens barrel 25. The image light is constituted by a set of on-lights toward the lens barrel 25.

  As shown in FIGS. 2 to 9, the lens barrel 25 is arranged in front of the front lens unit 41 and the rear lens unit 42 arranged in order from the front side, the support cylinder 43, and the support cylinder 43. And a cam cylinder 44 rotatably supported by 43. The cam cylinder 44 is covered with a cover cylinder 45 (see FIG. 1).

  The image light generated by the DMD 24 is imaged on the screen 15 by the lens units 41 and 42 of the lens barrel 25, and an image is projected on the screen 15.

  The front lens unit 41 includes a front projection lens 11 and a lens frame 47 that holds the front projection lens 11.

  Three roller mounting portions 47 a are formed on the outer peripheral surface of the lens frame 47 at a 120 ° pitch. A zoom roller 51 is rotatably attached to each of these three roller attachment portions 47a by attachment pins 52. An insertion recess 47b into which an end of the zoom roller 51 is inserted is formed in the roller mounting portion 47a.

  The mounting pin 52 includes a head portion 52a, a shaft portion 52b, and a screw portion 52c threaded with a diameter smaller than that of the shaft portion 52b. The screw portion 52 c is screwed into a screw hole 47 c formed in the roller mounting portion 47 a, the shaft portion 52 b is inserted through the insertion hole 51 a formed in the zoom roller 51, and the head portion 52 a is formed in the zoom roller 51. Is stored in the storage recess 51b.

  Similar to the front lens unit 41, the rear lens unit 42 includes a rear projection lens 12 and a lens frame 47, and three zoom rollers 51 are rotatably attached to the lens frame 47.

  The zoom rollers 51 of the lens units 41 and 42 are inserted into the outer peripheral surface of the support cylinder 43, and extend straight along the optical axis direction so as to guide the movement of the lens units 41 and 42 in the optical axis direction. A guide hole 43a is formed. The three rectilinear guide holes 43a are formed at a 120 ° pitch. A flange portion 43 b is formed at the rear end portion of the support cylinder 43, and the flange portion 43 b is fixed to the case 14 of the projector 10. A support portion (not shown) for rotatably supporting the cam cylinder 44 is provided on the outer peripheral surface of the support cylinder 43.

  The zoom rollers 51 of the lens units 41 and 42 are inserted into the outer peripheral surface of the cam cylinder 44, and the lens units 41 and 42 are moved in the direction of the optical axis when the cam cylinder 44 is rotated. A cam hole (hereinafter referred to as a front cam hole) 61 and a rear cam hole for movement (hereinafter referred to as a rear cam hole) 62 are formed. Three each of the cam holes 61 and 62 are formed at a 120 ° pitch.

  As shown in FIGS. 9 and 10, the front cam hole 61 includes a first inclined portion 61a and a second inclined portion 61b that are inclined with respect to the optical axis direction. The second inclined portion 61b has a smaller inclination angle with respect to the optical axis direction than the first inclined portion 61a, and has a larger amount of movement for moving the front lens unit 41 than the first inclined portion 61a when the cam cylinder 44 rotates. Similarly, the rear cam hole 62 includes a first inclined portion 62a and a second inclined portion 62b, and the second inclined portion 62b has an inclination angle with respect to the optical axis direction smaller than that of the first inclined portion 62a.

  A rotation restricting hole 66 for restricting the rotation region of the cam cylinder 44 is formed along the rotation direction behind the rear cam hole 62 of the cam cylinder 44. A limiting member 68 attached to the support cylinder 43 is engaged with the rotation limiting hole 66. The rotation restriction hole 66 is formed continuously with the first restriction part 66a with which the restriction member 68 engages when each zoom roller 51 moves on the first inclined parts 61a and 62a, and the first restriction part 66a. The zoom roller 51 includes a second restricting portion 66b with which a restricting member 68 engages when the second inclined portions 61b and 62b move. The first restricting portion 66a has a narrower hole width than the second restricting portion 66b. The portion where the hole width changes from the first restricting portion 66a to the second restricting portion 66b is inclined so that the hole width changes smoothly.

  As shown in FIG. 11, the limiting member 68 is attached to the attachment hole 43 c (see FIG. 4) of the support cylinder 43. The restricting member 68 is made of an elastically deformable material (for example, polyacetal and is formed in a cylindrical shape having a flange portion 68 b. The flange portion 68 b is fixed to the support cylinder 43.

  The restriction member 68 is formed with two slits 68a (see FIG. 4), and the restriction member 68 can be deformed in the hole width direction of the rotation restriction hole 66 by the slit 68a. As shown in FIGS. 9 and 12, when the first restricting portion 66a is moved, the restricting member 68 moves in a state of being deformed into an elliptical shape. As shown in FIGS. 10 and 11, when the restricting member 68 moves in the second restricting portion 66 b of the rotation restricting hole 66, the restricting member 68 moves in a state of returning to the original substantially circular shape. The restricting member 68 may be formed in a deformable thin cylindrical shape.

  The zoom adjustment mechanism 26 includes a motor 71 and a transmission mechanism 72 (all of which are shown in FIG. 2) including a plurality of gears that transmit the rotation of the motor 71 to the cam cylinder 44. The zoom adjustment mechanism 26 drives the motor 71 according to the rotation (operation) of the rotary zoom dial 16 to rotate the cam cylinder 44 via the transmission mechanism 72. By the rotation of the cam cylinder 44, zoom adjustment of the projected image (image projected on the screen 15) is performed.

  Next, the operation of the above embodiment will be described. Illumination light emitted from the light source 21 enters the color wheel 31. The illumination light incident on the color wheel 31 is color-separated into three colors B, G, and R by time division by the color wheel 31.

  The light separated by the color wheel 31 is homogenized by repeating reflection while passing through the rod integrator 32. The light beam emitted from the rod integrator 32 is relayed to the mirror 35 by the relay lenses 33 and 34, and this light beam is reflected by the mirror 35 toward the total reflection prism 23.

  The incident light reflected by the mirror 35 and incident on the total reflection prism 23 is incident on the DMD 24 after being totally reflected by the reflection surface 23a because the incident angle is larger than the critical angle.

  The DMD 24 changes the reflection direction of the received illumination light by changing the angles of a large number of mirror elements arranged in a matrix on the light receiving surface based on the projected image. The image light generated by the DMD 24 is incident on the lens barrel 25 through the reflecting surface 23 a because the incident angle is smaller than the critical angle.

  The image light incident on the lens barrel 25 passes through the rear projection lens 12 and the front projection lens 11 and is imaged on the screen 15. As a result, an image is projected on the screen 15.

  When the zoom dial 16 is rotated (operated), the zoom adjustment mechanism 26 drives the motor 71 in accordance with the rotation angle (operation amount) of the rotary zoom dial 16 and transmits it via the transmission mechanism 72. The cam cylinder 44 is rotated.

  When the cam cylinder 44 is rotated, the zoom rollers 51 of the lens units 41 and 42 move along the cam holes 61 and 62 while rotating, whereby the lens units 41 and 42 move in the optical axis direction. . At this time, since each zoom roller 51 moves along the rectilinear guide hole 43a of the support cylinder 43, each lens unit 41, 42 moves in the optical axis direction without rotating. As the lens units 41 and 42 move, zoom adjustment of the projected image (image projected on the screen 15) is performed. In the present embodiment, the lens units 41 and 42 move forward by the clockwise rotation of the cam cylinder 44, and the lens units 41 and 42 move backward by the rotation of the cam cylinder 44 counterclockwise. To do.

  As the cam cylinder 44 rotates in the clockwise direction, each zoom roller 51 of the front lens unit 41 moves through the front cam hole 61, and each zoom roller 51 of the rear lens unit 42 moves through the rear cam hole 62. Further, the limiting member 68 moves through the rotation limiting hole 66. When each zoom roller 51 of the front lens unit 41 moves along the first inclined portion 61a of the front cam hole 61, each zoom roller 51 of the rear lens unit 42 moves along the first inclined portion 62a, as shown in FIGS. As shown, the restricting member 68 moves through the first restricting portion 66a of the rotation restricting hole 66 while being deformed into an elliptical shape.

  As shown in FIGS. 10 and 11, when each zoom roller 51 of the front lens unit 41 moves from the first inclined portion 61a to the second inclined portion 61b, each zoom roller 51 of the rear lens unit 42 becomes the first inclined portion 62a. The restricting member 68 moves from the first restricting portion 66a to the second restricting portion 66b, and is elastically deformed into the original substantially circular shape.

  When the zoom rollers 51 of the lens units 41 and 42 move along the second inclined portions 61b and 62b, the limiting member 68 has a substantially perfect circle shape and moves the second limiting portion 66b. When the restriction member 68 is elastically deformed from an elliptical shape to a perfect circle shape, a load applied from the restriction member 68 to the cam cylinder 44 is reduced. That is, when the restricting member 68 moves the second restricting portion 66b, the load applied to the cam cylinder 44 becomes smaller than when the restricting member 68 moves the first restricting portion 66a.

  Since the second inclined portions 61b and 62b have a smaller inclination angle with respect to the optical axis direction than the first inclined portions 61a and 62a, when each zoom roller 51 moves through the second inclined portions 61b and 62b, each zoom roller 51 The load applied to the cam cylinder 44 becomes larger than when the first inclined portions 61a and 62a are moved.

  In this embodiment, when each zoom roller 51 moves the first inclined portions 61a and 62a, the load applied to the cam tube 44, and when the limiting member 68 is elliptical and moves the first limiting portion 66a, the cam tube 44 is moved. The first addition load to which the load applied to the first load is added and the load applied to the cam cylinder 44 when each zoom roller 51 moves on the second inclined portions 61b and 62b, the second limiting portion 66b having a perfect circle shape as the limiting member 68. The second addition load to which the load applied to the cam cylinder 44 is added when moving is substantially the same. As a result, the load applied to the motor 71 when the cam cylinder 44 is rotated is substantially constant, so that the driving sound of the motor 71 is constant.

  In the present embodiment, the first limiting portion 66a is set at the inclination angles of the first inclined portions 61a and 62a and the second inclined portions 61b and 62b so that the first additional load and the second additional load are substantially the same. Accordingly, it is formed narrower than the second restricting portion 66b, and the hole width of the first restricting portion 66a is determined according to the hole width of the second restricting portion 66b. Specifically, as the difference in inclination angle between the first inclined portions 61a and 62a and the second inclined portions 61b and 62b increases, the hole width of the first restricting portion 66a becomes narrower.

  When the cam cylinder 44 is rotated, the rotation of the cam cylinder 44 is restricted by the limiting member 68 coming into contact with both ends of the rotation limiting hole 66. When the restricting member 68 comes into contact with both ends of the rotation restricting hole 66, the zoom rollers 51 of the lens units 41 and 42 do not come into contact with both ends of the cam holes 61 and 62.

  Further, as shown in FIGS. 13 and 14, a front cam hole 81, a rear cam hole 62, and a linear rotation restriction hole 82 are formed in the cam cylinder 80, and the first inclined portion 81a of the front cam hole 81 is The width may be narrower than the second inclined portion 81b. The hole width changes smoothly from the first inclined portion 81a to the second inclined portion 81b. The zoom roller 83 engaged with the front cam hole 81 is formed in a deformable thin cylindrical shape. The limiting member 84 engages with the rotation limiting hole 82. Note that the zoom roller 83 may be formed in a cylindrical shape, and a slit may be formed to allow deformation.

  As shown in FIG. 13, the zoom roller 83 moves in a state of being deformed into an elliptical shape when moving the first inclined portion 81a. As shown in FIG. 14, when moving the second inclined portion 81b, the zoom roller 83 moves in a substantially circular state. Also in this embodiment, the load applied to the cam cylinder 44 when the zoom roller 83 and the zoom roller 51 move the first inclined portions 81a and 62a, and the zoom roller 83 and the zoom roller 51 move the second inclined portions 81b and 62b. When this is done, the load applied to the cam cylinder 44 is substantially the same.

  Although the hole width of the rear cam hole may be changed, it is preferable to change the hole width of the front cam hole having a large inclination angle with respect to the optical axis direction and a small movement range of the lens unit (small zoom amount). Further, both the rotation limiting hole and the front cam hole may be changed in width, and both the limiting member and the zoom roller may be provided so as to be elastically deformable.

  Further, as shown in FIG. 15, a straight rotation limiting hole 91 is formed in the cam cylinder 90, and side holes 92 are formed on both sides of the rotation limiting hole 91 in the same range as the second inclined portions 61b and 62b. It may be formed. A limiting member 93 is engaged with the rotation limiting hole 91. When the restricting member 93 moves in a portion where the side hole 92 is not formed, the restricting member 93 receives a load from the side wall that forms the rotation restricting hole 91. When the restricting member 93 moves in the portion where the side hole 92 is formed, the side wall can be deformed, so that the load received from the side wall is reduced.

  Furthermore, in the above-described embodiment, the present invention is implemented for a projector that rotates a cam cylinder by a motor. However, the present invention can also be implemented for a projector that manually rotates a cam cylinder. In this manual type projector, the operating load on the operator when rotating the cam cylinder is always almost constant, so that the operability is improved.

  In the above embodiment, the limiting member is formed in a cylindrical shape, but may be formed in a cylindrical shape such as a quadrangle or a pentagon.

  Further, in the above embodiment, the cam cylinder is arranged outside the support cylinder, but the cam cylinder may be arranged inside the support cylinder.

  In the above-described embodiment, the projector that performs zoom adjustment by moving the front projection lens and the rear projection lens is described. However, the present invention can also be applied to a projector that performs focus adjustment by movement of each projection lens. it can.

  Furthermore, in the above embodiment, a projector using DMD is described, but a transmissive liquid crystal panel or a reflective liquid crystal panel may be used as an image forming element.

  Moreover, although the projector has been described in the above embodiment, the present invention can also be applied to a digital camera or a film camera.

DESCRIPTION OF SYMBOLS 10 Projector 11 Front projection lens 12 Rear projection lens 25 Lens barrel 41 Front lens unit 42 Rear lens unit 43 Support cylinder 44, 80, 90 Cam cylinder 51, 83 Zoom roller 61, 81 Front cam hole 61a, 81a 1st inclination part 61b, 81b Second inclined portion 62 Rear cam hole 62a First inclined portion 62b Second inclined portion 66, 82, 91 Rotation restriction hole 66a First restriction portion 66b Second restriction portion 68, 93 Restriction member 68a Slit

Claims (11)

A lens frame for holding the lens;
A cam follower provided in the lens frame;
A cam hole that engages with the cam follower is formed, and a cam cylinder that moves the lens frame in the optical axis direction by rotation, a rotation limiting hole that limits a rotation range is formed, and the cam hole is formed in the optical axis direction. And a second inclination having a smaller inclination angle with respect to the optical axis direction than the first inclination part and a larger amount of movement for moving the lens frame than the first inclination part during rotation. A cam cylinder composed of a portion,
A support cylinder that rotatably supports the cam cylinder;
An engagement member attached to the support cylinder and engaged with the rotation restriction hole,
The rotation restricting hole includes a first restricting portion with which the engaging member engages when the cam follower moves on the first inclined portion, and an engaging member when the cam follower moves on the second inclined portion. The first restricting portion is formed to be narrower than the second restricting portion according to the inclination angle of the first inclined portion and the second inclined portion,
The engaging member is provided so as to be elastically deformable in the hole width direction of the first restricting portion and the second restricting portion, and deforms following the change in the hole width of the first restricting portion and the second restricting portion. A lens barrel characterized by   The lens barrel according to claim 1, wherein the engaging member is formed in a cylindrical shape and is formed with a slit for enabling deformation.   The lens barrel according to claim 1, wherein the engaging member is formed in a deformable thin cylindrical shape.   The lens barrel according to any one of claims 1 to 3, wherein the first restricting portion and the second restricting portion are connected by an inclined surface so that the hole width changes smoothly. A lens frame for holding the lens;
A cam follower provided in the lens frame;
A cam cylinder that is formed with a cam hole that engages with the cam follower and moves the lens frame in the optical axis direction by rotation; the cam hole being inclined with respect to the optical axis direction; A cam cylinder composed of a second inclined portion having an inclination angle with respect to the optical axis direction smaller than that of the first inclined portion and a large amount of movement for moving the lens frame relative to the first inclined portion during rotation;
A support cylinder that rotatably supports the cam cylinder,
The first inclined part is formed narrower than the second inclined part according to the inclination angle of the first inclined part and the second inclined part,
The cam follower is provided so as to be elastically deformable in a hole width direction of the first inclined portion and the second inclined portion, and is deformed following the change in the hole width of the first inclined portion and the second inclined portion. A lens barrel.   6. The lens barrel according to claim 5, wherein the cam follower is formed in a cylindrical shape and is formed with a slit for enabling deformation.   6. The lens barrel according to claim 5, wherein the cam follower is formed in a deformable thin cylindrical shape.   The lens barrel according to any one of claims 5 to 7, wherein the first inclined portion and the second inclined portion are connected by an inclined surface so that the hole width changes smoothly. A plurality of the lens frames are provided,
The cam cylinder is formed with a plurality of cam holes having different inclination angles with respect to the optical axis direction,
One of the plurality of cam holes having the largest inclination angle and the smallest movement amount for moving the lens frame is such that the first inclined portion has a hole width narrower than the second inclined portion, In the cam hole, the first inclined portion and the second inclined portion are formed with the same hole width,
One of the cam followers attached to each cam follower is engaged with the cam hole whose hole width changes, and is provided so as to elastically deform following the change in the hole width of the cam hole. 9. The lens barrel according to claim 5, wherein the cam follower is provided so as not to be deformed. The cam cylinder is formed with a rotation limiting hole for limiting a rotation range,
The lens barrel according to claim 5, wherein an engagement member that engages with the rotation restriction hole is attached to the support cylinder.   The lens barrel according to claim 1, wherein the cam barrel is rotated by a motor.

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