WO2010021150A1 - Lens barrel and imaging device - Google Patents

Abstract

A lens barrel equipped with an object-side lens guided by a guide bar, wherein the lens barrel is provided with a first guide shaft provided on the inner peripheral side of a fixed tube so as to extend in the direction of the axis thereof, a second guide shaft provided on the outer peripheral side of the fixed tube so as to extend in the direction of the axis and having at least a portion thereof overlapping the first guide shaft in the longitudinal direction thereof, a first holding member for holding a first lens, having a first engaging section engaging with the first guide shaft, and moving along the first guide shaft, and a second holding member for holding a second lens located on the object side of the first lens, having a second engaging section engaging with the second guide shaft, and moving along the second guide shaft.  The range of movement of the first engaging section along the first guide shaft and the range of movement of the second engaging section along the second guide shaft at least partially overlap each other in the direction of the axis.

Description

Lens barrel and imaging device

The present invention relates to a lens barrel and an imaging apparatus. This application is related to the following Japanese application. For designated countries where incorporation by reference of documents is permitted, the contents described in the following application are incorporated into this application by reference and made a part of this application.
Japanese Patent Application No. 2008-213360 Application date: August 21, 2008 Japanese Patent Application No. 2008-257562 Application date: October 02, 2008 Patent Application No. 2009-166161 Application date: July 14, 2009

Patent Document 1 listed below includes a moving cylinder that is guided by a guide pipe provided in a fixed cylinder and moves relative to the fixed cylinder, and a front group lens that is guided by a guide bar disposed in the movable cylinder. A lens barrel is described.

Patent Document 2 below describes a lens barrel that includes a guide bar that guides the moving direction, and a lens frame that has a sleeve that engages with the guide bar and holds the lens. The sleeve is further provided with a cam follower, and the lens frame is moved along the optical axis direction of the lens by rotating a cam cylinder having a cam groove engaged with the cam follower.

Japanese Patent Laid-Open No. 02-210314 Japanese Patent Laid-Open No. 06-174998

The above lens barrel has a structure for driving the front lens group with respect to individual guide bars. However, the rear group lens moves relative to the moving cylinder, and cannot be moved independently of the movement of the front group lens. Further, when a plurality of lens groups that move independently are provided for one guide bar, a guide bar having a length corresponding to the amount of movement is required. The structure for providing such a guide bar is a lens. This leads to an increase in the size of the lens barrel. Further, in the conventional lens barrel, an external impact is applied to the cam groove and the cam follower, and the cam groove and the cam follower may be damaged.

Therefore, in order to solve the above problems, as a first aspect of the present invention, a first guide shaft (142) provided along the axial direction of the fixed cylinder on the inner peripheral side of the cylindrical fixed cylinder (140), A second guide shaft (194) provided along the axial direction on the outer peripheral side of the fixed cylinder, and at least a part of which is overlapped with the first guide shaft in the longitudinal direction of the first guide shaft; A first holding member (122) that holds the lens (124) and has a first engagement portion (161) that engages with the first guide shaft and moves along the first guide shaft; The second lens (114) positioned on the object side of the lens is held, and a second engaging portion (117) that engages with the second guide shaft is provided and moved along the second guide shaft. A holding member (112), a moving range of the first engaging portion on the first guide shaft, and a second plan of the second engaging portion. A moving range in the axial, the lens barrel, characterized in that with overlapping at least a portion the axial direction (100) is provided.

As a second aspect of the present invention, a lens holding member (212) that holds the lens (211), a guide shaft (242) that guides the lens holding member to be movable, and a first cam follower provided on the lens holding member. The first cam follower and the first cam have a first cam surface (251) that engages with (217) and a second cam surface (252) that can engage with a second cam follower (219) provided on the lens holding member. A cam member (250) for driving the lens holding member along the guide shaft by the engagement of the surfaces, wherein the cam member has a gap between the second cam follower and the second cam surface. A lens barrel (100) is provided.

Furthermore, as a third aspect of the present invention, an imaging device (400) including the lens barrel (100) and an imaging unit (300) that captures an image by the lens is provided.

1 is a cross-sectional view of a lens barrel 100. FIG. 2 is an exploded perspective view of a lens barrel 100. FIG. 4 is a perspective view of a fixed cylinder 240. FIG. FIG. 10 is another perspective view of the fixed cylinder 240. 3 is a perspective view of an intermediate unit 160. FIG. 4 is a rear view of the intermediate unit 160. FIG. 4 is a perspective view of a rear group unit 130. FIG. 4 is a rear view of the rear group unit 130. FIG. FIG. 6 is a perspective view showing the movement of the intermediate unit 160 and the rear group unit 130. FIG. 6 is a perspective view showing the movement of the intermediate unit 160 and the rear group unit 130. 4 is a perspective view of a cam cylinder 250. FIG. 6 is another perspective view of the cam cylinder 250. FIG. 4 is a perspective view showing an assembly of a fixed cylinder 240, an intermediate unit 160, a rear group unit 130, and a cam cylinder 250. FIG. 3 is a perspective view of a front group unit 110. FIG. 4 is a rear view of a front group unit 110. FIG. It is a perspective view which shows the state which assembled | attached the front group unit 110 to the assembly of FIG. 1 is a cross-sectional view of a lens barrel 100. FIG. It is a perspective view which shows the cam cylinder 250 independently. 4 is a perspective view showing a relationship between a fixed cylinder 240 and a cam cylinder 250. FIG. FIG. 6 is a development view of the cam cylinder 250. 3 is a cross-sectional view schematically showing the relationship among a fixed cylinder 240, a cam cylinder 250, and a sliding cylinder 216. FIG. 1 is a diagram schematically illustrating a structure of an imaging apparatus 400 including a lens barrel 100. FIG.

100 lens barrel, 101 imaging optical system, 110 front group unit, 111 front cylinder, 112, 122, 132 lens frame, 113, 133, 163, 269, 218, 279 U-groove, 114 first lens group, 116, 136, 166, 268, 278 Cam follower, 117, 131, 161 engaging part, 118 screw, 119 screw hole, 121 middle cylinder, 124 second lens group, 130 rear group unit, 134 third lens group, 135 rear cylinder, 137, 167 V-shaped groove, 138, 141, 158 Notch part, 139, 169 Leaf spring, 140, 240 Fixed cylinder, 142, 144, 192, 194, 242, 261 Guide bar, 143, 147, 149 Bearing part, 145 rib part, 146 base part, 152, 154, 156 cam groove, 150 Cam cylinder, 151 zoom ring, 160 intermediate unit, 162, 264 diaphragm, 164, 262 vibration correction unit, 170 microcomputer, 210 first group, 211 front lens, 212, 265, 275 lens frame, 213 male lead, 214 lead Ring, 216 sliding cylinder, 217 driving cam follower, 215, 267, 277 fitting part, 219 buffering cam follower, 220 zoom ring, 222 non-slip, 241 opening, 244 mounting part, 246 cover part, 250 cam cylinder, 251, 253, 254 driving cam, 252 buffer cam, 258 notch, 260 second group, 266, 276 lens, 270 third group, 300 imaging unit, 310 imaging element, 312 optical filter, 320 shutter, 330 Ranging unit, 340 Mirror, 342 secondary mirror, 350 main controller, 360 mount, 370 pentaprism 372 focusing screen, 380 photometric unit, 390 a finder optical system, 392 a half mirror, 394 a finder LCD, 396 main LCD, 400 imaging device

Hereinafter, the present invention will be described through embodiments of the invention. However, the following embodiments do not limit the claimed invention. In addition, not all the combinations of features described in the embodiments are essential for the solving means of the invention.

FIG. 1 is a sectional view of the entire lens barrel 100. The lens barrel 100 includes an imaging optical system 101 having a first lens group 114, a second lens group 124 and a third lens group 134. The lens barrel 100 has a structure for adjusting a focal position, a focal length, and the like by moving at least one of the lens groups along the optical axis direction of the imaging optical system 101. The first lens group 114, the second lens group 124, and the third lens group 134 are held by lens frames 112, 122, and 132, respectively.

The fixed tube 140 has a base 146 connected to other members such as a camera body, and does not move or rotate with respect to the camera body or the like when the lens barrel 100 is attached. . In addition, the fixed cylinder 140 supports the guide bar 142 and the guide bar 144 in parallel to each other at positions facing the radial direction.

Further, the fixed cylinder 140 has another pair of guide bars 192 and 194. In FIG. 1, the outer guide bars 192 and 194 are arranged on the same cross section as the guide bars 142 and 144. However, this only indicates that the outer guide bars 192 and 194 are arranged outside the fixed tube 140.

The first lens group 114 is held by the front cylinder 111 via the lens frame 112, and forms a front group unit 110 including the front cylinder 111 and the lens frame 112. The front cylinder 111 is supported by the guide bars 192 and 194 by engaging the engaging portion 117 and the U-shaped groove 113 with the outer guide bars 192 and 194, and is driven by the cam cylinder 150 via the cam follower 116. Is done. Thereby, the front group unit 110 is displaced with respect to the fixed cylinder 140 along the optical axis of the imaging optical system 101 together with the first lens group 114. More specifically, the front group unit 110 moves to the object side (left side in the figure) or the image side (right side in the figure).

The second lens group 124 is held by the middle cylinder 121 via the lens frame 122. The middle cylinder 121 holds the diaphragm unit 162 and the vibration correction unit 164 together to form the intermediate unit 160. The vibration correcting unit 164 corrects vibration such as camera shake by moving the second lens group 124 so as to have a component in a direction substantially orthogonal to the optical axis of the imaging optical system 101.

The middle cylinder 121 has the engaging portion 161 and the U-shaped groove 163 engaged with the guide bars 142 and 144 (see FIGS. 5 and 6), and is along the optical axis of the imaging optical system 101 with respect to the fixed cylinder 140. Move. As a result, the lens frame 122 and the second lens group 124 held by the middle cylinder 121 also move along the guide bars 142 and 144.

When the longitudinal directions of the guide bars 142, 144, 192, 194 are compared, the guide bars 142, 144 on the inner side of the fixed tube 140 and the guide bars 192, 194 on the outer side of the fixed tube 140 are engaged portions 117. 161 and the U-shaped grooves 113 and 163 are overlapped with each other. The cam cylinder 150 is disposed between the guide bars 142 and 144 and the guide bars 192 and 194, and the front group unit 110 positioned on the outer side in the radial direction, and the intermediate unit 160 positioned on the inner side in the radial direction. Is also driven.

The third lens group 134 is held by the rear cylinder 135 via the lens frame 132. The rear cylinder 135 and the lens frame 132 form a rear group unit 130. The rear cylinder 135 also moves along the optical axis of the imaging optical system 101 with respect to the fixed cylinder 140 when the engaging portion 131 and the U-shaped groove 133 are engaged with the guide bars 142 and 144. As a result, the lens frame 132 and the third lens group 134 held by the rear cylinder 135 also move along the guide bars 142 and 144.

The intermediate unit 160 and the rear group unit 130 are disposed on the inner diameter side of the fixed cylinder 140. On the other hand, the front group unit 110 is disposed outside the fixed cylinder 140. The cam barrel 150 can be rotated with the same rotation center with respect to the fixed barrel 140 by operating a zoom ring 151 provided on the outer periphery of the lens barrel 100.

As will be described later, the cam cylinder 150 drives the front group unit 110, the intermediate unit 160, and the rear group unit 130 via the cam followers 116, 136, and 166. Hereinafter, each element will be described individually.

Further, the lens barrel 100 incorporates a microcomputer 170 in addition to the above members. The microcomputer 170 executes communication control when transmitting and receiving electrical signals to and from the outside of the lens barrel 100.

FIG. 2 is an exploded perspective view of the lens barrel 100. The lens barrel 100 is formed by assembling a front group unit 110, a cam cylinder 150, a fixed cylinder 140, an intermediate unit 160, and a rear group unit 130 in order from the left side of the drawing corresponding to the object side (front end side).

The lens barrel 100 includes a step in which one end (object side end) of the guide bars 142 and 144 is attached to the inside of the fixed barrel 140, and the intermediate unit 160 from the other end (image side end) side of the guide bars 142 and 144. And a step of sequentially performing the process of attaching the rear group unit 130. Also included is a procedure for sequentially executing a step of attaching the guide bars 192 and 194 to the outside of the fixed cylinder 140 and a step of attaching the front group unit 110 to the guide bars 192 and 194. The order of executing the former procedure and the latter procedure can be arbitrarily selected. In the following description, the object side end of each element is referred to as “tip”. In addition, an image side end portion of each element is referred to as a “rear end”.

FIG. 3 is a perspective view showing a state in which the fixed barrel 140 is looked down from the obliquely rear side of the lens barrel 100. FIG. 4 is a perspective view showing a state in which the fixed barrel 140 is looked down from the oblique front side of the lens barrel 100.

The fixed cylinder 140 has a cylindrical shape as a whole and includes guide bars 142, 144, 192, 194 and a base 146. The base 146 is an annular member formed at the rear end of the fixed barrel 140, and a mount for fixing the lens barrel 100 to another member is attached. A cutout 141 is formed on the peripheral surface of the fixed cylinder 140, and the function thereof will be described later.

The pair of guide bars 142 and 144 are arranged inside the fixed cylinder 140 in parallel with the longitudinal direction of the cylinder. As shown in FIG. 3, the rear ends of the guide bars 142 and 144 are inserted into and supported by bearing portions 147 and 149 on the image side of the lens barrel 100, that is, on the right side in the drawing. Further, as shown in FIG. 4, on the object side in the lens barrel 100, that is, on the left side in the drawing, the front ends of the guide bars 142, 144 are also inserted into and supported by the bearing portions 147, 149. Thus, the guide bars 142 and 144 are positioned at both ends, and the guide direction is prevented from being shaken.

The other pair of guide bars 192 and 194 are arranged outside the fixed cylinder 140 in parallel with the longitudinal direction of the cylinder. As shown in FIGS. 3 and 4, the rear ends (image side) of the guide bars 192 and 194 are inserted into and supported by a rib portion 145 formed on the outer periphery in the middle in the longitudinal direction of the fixed tube 140. As shown in FIG. 4, the front ends of the guide bars 142 and 144 are inserted and supported by a bearing portion 143 formed at the front end of the fixed cylinder. Thereby, the guide bars 192 and 194 are positioned at both ends, and the guide direction is prevented from being shaken.

FIG. 5 is a perspective view of the intermediate unit 160. FIG. 6 is a rear view of the intermediate unit 160. 5 and 6, a part of the intermediate unit 160 is omitted.

As shown in FIG. 5, the intermediate unit 160 is supported by the pair of guide bars 142 and 144 via the engaging portion 161 and moves along the guide bars 142 and 144. Since the intermediate unit 160 holds the guide bar 142 by the leaf spring 169 and the V-shaped groove 167 of the engaging portion 161, the intermediate unit 160 does not rattle.

Further, the intermediate unit 160 has a cam follower 166 adjacent to the engaging portion 161 in the circumferential direction. Thereby, it drives to the cam groove 154 of the cam cylinder 150 mentioned later. Thereby, in the imaging optical system 101, the second lens group 124 can be moved along the optical axis.

Further, as shown in FIG. 6, the middle cylinder 121 of the intermediate unit 160 has an engaging portion 161 and a U-shaped groove 163. The engaging portion 161 and the U-shaped groove 163 are arranged symmetrically with respect to the center C in the radial direction of the middle cylinder 121 indicated by a one-dot chain line A. As a result, the U-shaped groove 163 is arranged far away from the engaging portion 161 in the circumferential direction of the middle cylinder 121.

Therefore, rattling between the U-shaped groove 163 and the guide bar 144 and between the engaging portion 161 and the guide bar 142 can be suppressed. The second lens group 124 is accurately positioned in a plane orthogonal to the optical axis, so that the center C of the second lens group 124 can be prevented from deviating from the entire optical axis of the imaging optical system 101.

The V-shaped groove 167 of the engaging portion 161 has a symmetrical shape with respect to the circumferential direction of the middle cylinder 121 with respect to the alternate long and short dash line A. Thus, the plurality of surfaces forming the V-shaped groove 167 may be symmetric with respect to the surface including the optical axis of the imaging optical system 101 and the guide bar 142. Thereby, the resultant force of the force with which the guide bar 142 presses the plurality of surfaces of the V-shaped groove 167 is directed toward the center of the optical axis of the imaging optical system 101, and therefore the position of the second lens group 124 within the surface orthogonal to the optical axis Can be stabilized.

FIG. 7 is a perspective view showing a state in which the rear group unit 130 is looked down from the oblique front side of the lens barrel 100. FIG. 8 is a rear view when the rear group unit 130 is viewed from directly behind the lens barrel 100.

In the rear group unit 130, the rear cylinder 135 holds the third lens group 134 inside via the lens frame 132. Further, an engaging portion 131, a cam follower 136, and a U-shaped groove 133 are disposed on the outer peripheral surface of the rear cylinder 135, respectively.

Here, the lens frame 132 and the third lens group 134 held by the lens frame 132 are arranged near the rear end (left side in the drawing) of the rear cylinder 135. On the other hand, the engaging portion 131 is disposed closer to the front end (right side in the drawing) of the rear cylinder 135. Thereby, the third lens group 134 is arranged closer to the image side with respect to the engaging portion 131 in the optical axis direction of the imaging optical system 101.

A notch 138 is formed on the outer peripheral surface of the rear cylinder 135 along the longitudinal direction of the rear cylinder 135. In the region where the notch 138 is formed, a plurality of engaging portions 131 are arranged along the circumferential direction of the rear cylinder 135. As described above, the rear cylinder 135 is partly cut off by the notch 138 and appears discontinuous, but the rear cylinder 135 is connected by the engaging part 131 and becomes a cylinder as a whole.

As shown in FIG. 7, the engaging portion 131 is arranged away along the extending direction of the guide bar 142. Thereby, it can suppress that the guide bar 142 and the longitudinal direction of the rear cylinder 135 incline relatively. In addition, a V-shaped groove 137 formed by a pair of contact surfaces facing each other that contact the guide bar 142 is formed on the upper surface of each engagement portion 131.

Furthermore, when the rear group unit 130 is viewed from the back, a cam follower 136 is disposed adjacent to the engaging portion 131 on the outer peripheral surface of the rear cylinder 135. The cam follower 136 protrudes in the radial direction from the surface of the rear cylinder 135.

In the vicinity of the cam follower 136, a leaf spring 139 has one end fixed to the rear cylinder 135. The other end of the leaf spring 139 contacts the guide bar 142. Thereby, the leaf spring 139 attracts the engaging portion 131 toward the guide bar 142. Therefore, the V-shaped groove 137 and the guide bar 142 are in close contact with each other. This prevents the center of the third lens group 134 from being shifted from the optical axis of the entire imaging optical system 101.

On the other hand, as shown in FIG. 8, the U-shaped groove 133 engages with the guide bar 144 at a position different from the engaging portion 131. The U-shaped groove 133 sandwiches the side surface of the guide bar 144 from the circumferential direction of the rear cylinder 135 by a pair of contact surfaces parallel to each other. Thereby, it is possible to suppress the rear cylinder 135 from rotating in a plane orthogonal to the optical axis of the imaging optical system 101.

FIG. 9 shows a state where the intermediate unit 160 and the rear group unit 130 assembled to the fixed barrel 140 are located on the rear end side of the lens barrel 100. That is, the intermediate unit 160 and the rear group unit 130 are inserted inside the fixed cylinder 140.

The engaging portion 131 of the rear cylinder 135 is engaged with the guide bar 142. In addition, the cam follower 136 of the rear cylinder 135 protrudes from the fixed cylinder 140 through the notch 141. The engaging part 161 of the intermediate unit 160 is engaged with the guide bar 142, and the cam follower 166 is exposed to the outside through the notch part 141 of the fixed cylinder 140.

Here, since the leaf springs 169 and 139 of the intermediate unit 160 and the rear group unit 130 are both thin, they are within the thickness range of the fixed cylinder 140. Therefore, the leaf springs 169 and 139 do not protrude outward from the outer peripheral surface of the fixed cylinder 140.

Further, the cam followers 166 and 136 are located on the opposite sides with respect to the guide bar 142 in the circumferential direction of the fixed cylinder 140. Therefore, even when the cam followers 166 and 136 approach in the extending direction of the guide bar 142, they do not interfere with each other.

FIG. 10 shows a state in which the intermediate unit 160 and the rear group unit 130 assembled to the fixed barrel 140 are located on the front end side of the lens barrel 100. Also in this case, since the cam followers 166 and 136 are located on the opposite side with respect to the guide bar 142, they do not interfere with each other.

Thus, the cam follower 166 of the intermediate unit 160 and the cam follower 136 of the rear group unit 130 are located on the opposite sides of the guide bar 142 in the circumferential direction of the fixed barrel 140. Therefore, even when the pair of cam followers 166 and 136 approach in the extending direction of the guide bar 142, they do not interfere with each other. As a result, both the intermediate unit 160 and the rear group unit 130 are guided by the single guide bar 142, but the movement range of the intermediate unit 160 and the rear group unit 130 can be widened.

FIG. 11 is a perspective view showing a state in which the left side surface is looked down from the rear of the single cam cylinder 150. FIG. 12 is a perspective view showing a state in which the right side surface is looked down from the rear of the cam cylinder 150.

The cam cylinder 150 as a whole has a cylindrical shape in which a notch 158 is provided in a part of the peripheral surface. Further, a plurality of cam grooves 152, 154, and 156 are formed on the circumferential surface of the cam cylinder 150 so as to extend without intersecting with either the circumferential direction or the longitudinal direction.

In the cam cylinder 150, cam grooves 152, 154, and 156 are formed in order from the front end side. In addition, the cam grooves 154 and 156 are removed from the rear portion of the cam cylinder 150 to form a notch 158. On the other hand, the front portion of the cam cylinder 150 has no notch 158, and the cam cylinder 150 has a cylindrical shape. As a result, when the cam cylinder 150 is mounted on the outer peripheral surface of the fixed cylinder 140, the cam cylinder 150 rotates along the outer peripheral surface of the fixed cylinder 140.

FIG. 13 is a perspective view showing a state where the cam cylinder 150 is assembled to the assembly shown in FIGS. 11 and 12. Constituent elements common to other drawings are denoted by the same reference numerals, and redundant description is omitted.

The cam cylinder 150 is attached to the outside of the assembly in which the intermediate unit 160 and the rear group unit 130 are assembled to the fixed cylinder 140. As a result, the cam followers 166 and 136 projecting radially outward from the fixed cylinder 140 engage with the cam grooves 154 and 156.

The cam followers 136 and 166 may be configured to be attached to the middle cylinder 121 or the rear cylinder 135 from the outside of the cam cylinder 150 through the cam grooves 154 and 156 after the cam cylinder 150 is mounted on the outer side of the fixed cylinder 140. Further, at the stage shown in FIG. 13, the outer guide bars 192 and 194 are exposed through the front portion of the cam cylinder 150.

The cam follower 166 of the intermediate unit 160 engages with the cam groove 154 of the cam cylinder 150. The moving direction of the intermediate unit 160 is limited to the extending direction of the guide bars 142 and 144 by the engaging portion 161 and the U-shaped groove 163. Therefore, when the cam cylinder 150 rotates along the fixed cylinder 140 around the optical axis of the imaging optical system 101, the cam follower 166 pushed by the cam groove 154 moves in the optical axis direction of the lens barrel 100. Thus, the second lens group 124 held by the middle cylinder 121 moves along the optical axis direction.

Similarly, the cam follower 136 of the rear group unit 130 engages with the cam groove 156 of the cam barrel 150. The movement direction of the rear group unit 130 is limited to the extending direction of the guide bars 142 and 144 by the engaging portion 131 and the U-shaped groove 133. Therefore, when the cam cylinder 150 rotates with respect to the fixed cylinder 140 around the optical axis of the imaging optical system 101, the cam follower 136 pushed by the cam groove 156 moves in the optical axis direction of the lens barrel 100. Thus, the third lens group 134 held by the rear group unit 130 also moves along the optical axis direction.

On the other hand, the cam follower 116 engages with the cam groove 152 alone. The cam follower 116 has a screw hole 119 at the center thereof. Thereby, when the front group unit 110 described later is mounted, the front tube 111 and the cam follower 116 can be coupled.

FIG. 14 is a perspective view of the front group unit 110. FIG. 15 is a rear view of the front group unit 110. As already described, the guide bars 192 and 194 are members fixed to the fixed cylinder 140, but are drawn together with FIGS. 14 and 15 for the purpose of easily understanding the function of the front group unit 110. .

As shown in FIG. 14, the front cylinder unit includes a front cylinder 111, an engagement portion 117, a U-shaped groove 113, and a cam follower 116. The front cylinder 111 forms a cylinder as a whole, and has a lens frame 112 at its front end (left end in the figure). On the other hand, the engaging portion 117 and the U-shaped groove 113 are arranged near the rear end (left side in the drawing) of the front cylinder 111. Thereby, the first lens group 114 is arranged closer to the object side with respect to the optical axis direction of the imaging optical system 101 with respect to the engaging portion 117 and the U-shaped groove 113.

The engaging portion 117 and the U-shaped groove 113 are formed on the inner side of the front cylinder 111 so as to protrude radially inward. The positions of the engaging portion 117 and the U-shaped groove 113 correspond to the positions of the pair of guide bars 192 and 194 supported by the fixed cylinder 140. Furthermore, each of the engaging portions 117 has a through hole having an inner diameter through which the guide bar 194 can be smoothly inserted. As a result, the front group unit 110 is smoothly displaced along the guide bars 192 and 194.

The cam follower 116 is disposed in the vicinity of the engaging portion 117 along the circumferential direction of the front cylinder 111. Further, when viewed in the extending direction of the guide bar 194, the cam follower 116 is disposed at the center of the pair of engaging portions 117. Thereby, when the cam follower 116 receives a driving force, the driving force is evenly applied to the pair of engaging portions 117, so that the front group unit 110 moves smoothly. In addition, when the front cylinder 111 is formed with resin etc., you may shape | mold the engaging part 117 and the U-shaped groove 113 integrally.

Also, when the front group unit 110 moves, the distance between the pair of engaging portions 117 that support the front cylinder 111 does not change. Accordingly, the posture of the front cylinder 111 is stabilized regardless of the position of the front group unit 110, and the change in the optical characteristics of the first lens group 114 is prevented.

Further, as shown in FIG. 15, the cam follower 116 protrudes inward in the radial direction of the front cylinder 111. Thereby, when the front group unit 110 is assembled to the lens barrel 100, the cam follower 116 and the cam groove 152 are engaged. Therefore, when the cam cylinder 150 rotates around the fixed cylinder 140, the cam follower 116 is pushed by the cam groove 152 to drive the entire front group unit 110.

Further, the cam follower 116 is coupled to the inside of the front cylinder 111 by a screw 118. Therefore, for example, as shown in FIG. 13, the front group unit is assembled by attaching the front cylinder 111 after the cam follower 116 is assembled to the cam cylinder 150 and connecting the front cylinder 111 and the cam follower 116 with the screws 118. 110 can be assembled to the fixed cylinder 140.

FIG. 16 is a perspective view showing a state in which the front group unit 110 is assembled to the assembly shown in FIG. As illustrated, the front group unit 110 is mounted on the outside of the assembly so that the front cylinder 111 surrounds the guide bars 192 and 194 from the outside. As a result, a structure is formed in which the front group unit 110 holding the first lens group 114 positioned further forward than the tip of the fixed cylinder 140 on the object side is supported by the guide bars 192 and 194.

As described above, the cam follower 116 protruding inward of the front cylinder 111 engages with the cam groove 152 on the front end side of the cam cylinder 150. Therefore, when the cam cylinder 150 rotates, the front group unit 110 also has a cam groove. It moves according to the cam profile of 152. Therefore, by operating the single cam barrel 150, the lens barrel 100 can perform a zoom operation with a large magnification, for example.

In addition, each of the front group unit 110, the intermediate unit 160, and the rear group unit 130 is guided to the guide bars 142 and 194 by a pair of engaging portions 117, 131, and 161, respectively. Therefore, each of the front group unit 110, the intermediate unit 160, and the rear group unit 130 moves without the respective optical axes being shaken.

FIG. 17 is a cross-sectional view showing the structure of the lens barrel 100. Moreover, the upper side of FIG. 17 shows a state in which the first group 210 has moved backward, and the lower side in FIG. 17 shows a state in which the first group 210 has advanced by zooming.

The lens barrel 100 includes a fixed barrel 240, a cam barrel 250, a sliding barrel 216, and a zoom ring 220 that are arranged coaxially with respect to the optical axis C thereof. The fixed cylinder 240 has a mount portion 244 at the rear end corresponding to the right side in the drawing. The mount portion 244 is fitted to a mount provided on a body such as a camera and supports the fixed cylinder 240.

Also, the fixed cylinder 240 includes a pair of guide bars 242 on the outer peripheral side in the vicinity of the front end corresponding to the left side in the drawing. Both ends of the guide bar 242 are fixed to the fixed cylinder 240, and the guide bar 242 is arranged in parallel with the optical axis C. Further, a cam cylinder 250 is disposed between the fixed cylinder 240 and the guide bar 242 along the outer peripheral surface of the fixed cylinder 240. The fixed cylinder 240 includes a pair of guide bars 261 on the inner peripheral side. Both ends of the guide bar 261 are fixed to the fixed cylinder 240, and the guide bar 261 is arranged in parallel with the optical axis C.

A sliding cylinder 216 is disposed outside the guide bar 242. The sliding cylinder 216 includes a fitting portion 215 and a U-shaped groove 218 that extend toward the radially inner side of the lens barrel 100. In the illustrated example, the fitting portion 215 and the U-shaped groove 218 are disposed along the guide bar 242. Each of the fitting portion 215 and the U-shaped groove 218 is fitted to the guide bar 242. As a result, the sliding cylinder 216 is guided by the guide bar 242 and moves along a direction parallel to the optical axis C.

The sliding cylinder 216 has a male lead 213 on the outer surface. The male lead 213 engages with the female lead on the inner peripheral surface of the lead ring 214. As a result, the lead ring 214 is focused by moving with respect to the sliding cylinder 216.

The lead ring 214 extends to the front of the guide bar 242 outside the sliding cylinder 216 and holds the lens frame 212 inside. The lens frame 212 holds the front ball 211. With such a structure, the front ball 211 also moves as the sliding cylinder 216 moves. The front lens 211 is not limited to a single lens, but may be a lens group in which a plurality of lenses are combined.

The zoom ring 220 is disposed outside the lead ring 214. When the zoom ring 220 is rotated, the cam cylinder 250 is rotated, and the sliding cylinder 216 moves along the guide bar, so that the sliding cylinder 216 moves integrally with the second group and the third group described later. Zoom.

The space between the rear end of the zoom ring 220 and the mount portion 244 of the fixed barrel 240 is covered by a cover portion 246 to prevent dust and the like from entering the lens barrel 100. The cover portion 246 is fixed to the fixed cylinder 240 and does not rotate. Further, the zoom ring 220 is provided with a non-slip 222 that is grasped by the user.

The lens barrel 100 further has a second group 260 and a third group 270. The second group 260 and the third group 270 are supported by the guide bar 261. The second group 260 and the third group 270 move in the direction of the optical axis C by receiving the driving force from the cam cylinder 250 and being guided by the guide bar 261.

The second group 260 includes a diaphragm unit 264 and a lens 266, a vibration correction unit 262 that corrects the vibration of the lens 266, and a lens frame 265 that holds the lens 266 via the vibration correction unit 262. The lens frame 265 includes a pair of fitting portions 267 that are spaced apart from each other along the guide bar 261, and a U-shape that is provided on the opposite side of the optical axis C with respect to the pair of fitting portions 267. A groove 269. The second group 260 is slidably supported on the guide bar 261 by fitting the pair of fitting portions 267 into one guide bar 261 and fitting another guide bar 261 into the U-shaped groove 269. The lens frame 265 further has a cam follower 268 protruding in the radial direction.

The third group 270 includes a lens 276 and a lens frame 275 that holds the lens 276. Similarly to the lens frame 265 of the second group 260, the lens frame 275 includes a pair of fitting portions 277, a U-shaped groove 279, and a cam follower 278. Since the configuration and operation of the fitting portion 277 and the U-shaped groove 279 are the same as those of the fitting portion 267 and the U-shaped groove 269, description thereof is omitted.

FIG. 18 is a perspective view showing the cam cylinder 250 alone. The cam cylinder 250 has a plurality of cam grooves including drive cams 251, 253, and 254 and a buffer cam 252. The driving cam 251 engages with the sliding cylinder 216 to drive the first group 210 as will be described later.

In the cam cylinder 250, areas where the drive cams 251, 253, and 254 and the buffer cam 252 are not formed are removed to form notches 258. Thereby, the lens barrel 100 can be reduced in weight, and the material of the cam barrel 250 can be saved.

FIG. 19 is a perspective view showing the relationship between the fixed cylinder 240 and the cam cylinder 250. As illustrated, the cam cylinder 250 is mounted along the outer surface of the fixed cylinder 240 and rotates along the peripheral surface of the fixed cylinder 240.

In FIG. 19, the driving cam follower 217 and the buffering cam follower 219 are inserted into the driving cam 251 and the buffering cam 252. The sliding cylinder 216 is coupled to the outer ends of the drive cam follower 217 and the buffer cam follower 219.

The driving cam 253 of the cam cylinder 250 drives the second group 260, and the driving cam 254 drives the third group 270. Correspondingly, the fixed tube 240 has an opening so that the fitting portion 267 and the cam follower 268 of the second group 260 and the fitting portion 277 and the cam follower 278 of the third group 270 can move relative to the fixed tube 240. 241 is provided.

FIG. 20 is a development view of the cam cylinder 250. The cross sections of the driving cam follower 217 and the buffering cam follower 219 that are engaged with the driving cam 251 and the buffering cam 252 are also shown.

As shown in the figure, the drive cam 251 and the buffer cam 252 have the same shape. On the other hand, the driving cams 253 and 254 have individual shapes different from the driving cam 251 and the buffer cam 252.

On the other hand, the driving cam follower 217 that engages with the cam surface of the driving cam 251 and the buffering cam follower 219 that can engage with the cam surface of the buffering cam 252 have different diameters. That is, the drive cam follower 217 has a diameter substantially the same as the width of the drive cam 251. For this reason, the driving cam follower 217 is in contact with the cam surface of the driving cam 251.

On the other hand, the buffer cam follower 219 has a radius smaller than the width of the buffer cam 252. For this reason, there is a gap between the cam surface of the buffer cam 252 and the buffer cam follower 219.

The cam follower 268 of the second group 260 is inserted into the driving cam 253. A cam follower 278 of the third group 270 is inserted into the drive cam 254. Here, the width of the drive cam 253 and the diameter of the cam follower 268 are substantially the same, and the width of the drive cam 254 and the diameter of the cam follower 278 are substantially the same. As a result, the cam follower 268 is driven along the driving cam 253 and the cam follower 278 is driven along the driving cam 254 as the cam cylinder 250 rotates.

FIG. 21 is a cross-sectional view schematically showing the relationship between the fixed cylinder 240, the cam cylinder 250, and the sliding cylinder 216. As shown in the figure, a cam cylinder 250 is mounted on the outer periphery of the fixed cylinder 240, and a sliding cylinder 216 is further disposed on the outer periphery thereof. A guide bar 242 extending in a direction perpendicular to the paper surface is disposed between the cam cylinder 250 and the sliding cylinder 216. Furthermore, the sliding cylinder 216 includes a driving cam follower 217 and a buffering cam follower 219 that protrude toward the optical axis of the lens barrel 100, a fitting portion 215 that engages with the guide bar 242, and a U-shaped groove 218.

The drive cam follower 217 and the buffer cam follower 219 are inserted into the drive cam 251 and the buffer cam 252, respectively. However, although the drive cam follower 217 is in contact with the cam surface of the drive cam 251, there is a gap between the buffer cam follower 219 and the cam surface of the buffer cam 252.

Here, the drive cam follower 217 is arranged closer to the fitting portion 215 than the buffer cam follower 219 in the circumferential direction. As a result, the driving force received by the driving cam follower 217 can be efficiently transmitted to the sliding cylinder 216. Further, it is possible to suppress the front ball 211 from being tilted.

The fitting portion 215 is inserted through the guide bar 242, and the guide bar 242 is fixed to the fixed cylinder 240. Therefore, when the cam cylinder 250 rotates and the driving cam follower 217 is pushed by the driving cam 251, the sliding cylinder 216 does not rotate.

Since the drive cam follower 217 is in contact with the cam surface of the drive cam 251, the sliding cylinder 216 moves along the guide bar 242 when the drive cam 251 drives the drive cam follower 217. As a result, the lead ring 214, the lens frame 212, and the front lens 211 also move together with the sliding cylinder 216.

On the other hand, since there is a gap between the cam surface of the buffer cam 252 and the buffer cam follower 219, the buffer cam follower 219 is not driven by the buffer cam 252. However, when the driving cam follower 217 or the like is deformed by a mechanical load applied to the first group unit including the front lens 211, the lens frame 212, the lead ring 214, and the sliding cylinder 216 from the outside, the buffering cam follower 219 is The load is distributed in contact with the cam surface of the buffer cam 252. Thereby, damage to the driving cam 251 and the driving cam follower 217 is suppressed.

In this way, the lens frame 212 including the lens frame 212 that holds the front lens 211, the lead ring 214, and the sliding cylinder 216, the guide bar 242 that guides the lens holding section to be movable, and the sliding cylinder 216 are provided. The driving cam follower 217 and the driving cam 251 include a driving cam 251 that engages with the driving cam follower 217 and a buffering cam 252 that can engage with the buffering cam follower 219 provided on the sliding cylinder 216. And the cam barrel 250 that drives the lens holding portion along the guide bar 242. The buffer cam follower 219 and the buffer cam 252 form the lens barrel 100 having a gap therebetween.

Thus, when an external load is applied to the first group, the load is distributed to the buffer cam 252 and the buffer cam follower 219, so that the practical strength is high and the durability is also increased. Therefore, the front ball 211 can be accurately guided by the guide bar 242 to prevent the optical performance of the lens barrel 100 from deteriorating.

In view of the action of the buffer cam follower 219 and the buffer cam 252 as described above, the drive cam follower 217 and the buffer cam follower 219 are arranged at equal intervals along the direction around the optical axis C of the lens barrel 100. . As a result, the load acting on the first group 210 can be more evenly distributed.

In the above embodiment, the first group 210, which is often subjected to external loads or impacts, has been described as an example. However, for example, when acceleration acts on the entire lens barrel 100, the members inside the lens barrel 100 are also subjected to the same impact as in the first group. Therefore, by adopting a structure like the first group 210 of the lens barrel 100, other lens groups can be protected.

In the above embodiment, the widths of the drive cam follower 217 and the buffer cam follower 219 are changed by making the widths of the drive cam 251 and the buffer cam 252 the same, so A gap was formed. However, a gap is formed between the buffer cam 252 and the buffer cam follower 219 by changing the widths of the drive cam 251 and the buffer cam 252 using the drive cam follower 217 and the buffer cam follower 219 having the same diameter. You can also

Furthermore, by making the elastic modulus of the buffer cam follower 219 lower than the elastic modulus of the drive cam follower 217, the impact dispersion effect by the buffer cam follower 219 and the buffer cam 252 can be further improved.

FIG. 22 is a diagram schematically showing the structure of the image pickup apparatus 400 provided with the lens barrel 100. In FIG. 22, the lens barrel 100 is schematically illustrated for the purpose of avoiding the complexity of the drawing. However, the lens barrel 100 in FIG. 22 has the same structure as the lens barrel 100 shown in FIG. Therefore, the same components are denoted by the same reference numerals, and redundant description is omitted.

The lens barrel 100 is detachably attached to the imaging unit 300 via the mount unit 360. In the imaging device 400, the lens barrel 100 and the imaging unit 300 are also electrically coupled via a connection terminal (not shown). Thereby, the lens barrel 100 is supplied with power from the imaging unit 300. In some cases, a sub-control unit is provided in the lens barrel 100 to exchange signals with the main control unit 350 of the imaging unit 300.

In the embodiment shown in FIGS. 17 to 21, the first group 210 is moved by the male lead 213 and the lead ring 214 during focusing. However, the focusing operation is not limited to this, and the first group 210 is moved by the guide bar 242. May be moved linearly. Similarly to the first group 210, the second group 260 and the third group 270 may have a structure including the buffer cam 252 and the buffer cam follower 219.

The imaging unit 300 accommodates an optical system including a main mirror 340, a pentaprism 370, and a finder optical system 390, and a main control unit 350. The main mirror 340 includes a standby position that is inclined on the optical path of incident light that has entered through the imaging optical system 101 of the lens barrel 100, and an imaging position that rises while avoiding incident light (indicated by a dotted line in the figure). Move between

The primary mirror 340 at the standby position guides most of the incident light to the focusing screen 372 disposed above. The focusing screen 372 is disposed at the in-focus position of the imaging optical system 101 of the lens barrel 100 and forms an image formed by the imaging optical system 101.

The image formed on the focusing screen 372 is observed from the finder optical system 390 via the pentaprism 370. As a result, the image on the focusing screen 372 can be viewed as a normal image from the finder optical system 390.

Between the pentaprism 370 and the finder optical system 390, a half mirror 392 that superimposes the display image formed on the finder LCD 394 on the image of the focusing screen 372 is disposed. Thereby, at the exit end of the finder optical system 390, the image on the focusing screen 372 and the image on the finder LCD 394 can be seen together. Note that information such as shooting conditions and setting conditions of the imaging apparatus 400 is displayed on the finder LCD 394.

Also, part of the light emitted from the pentaprism 370 is guided to the photometry unit 380. The photometry unit 380 measures the intensity of incident light, its distribution, and the like, and refers to the measurement result when determining imaging conditions.

On the other hand, a secondary mirror 342 is disposed on the back surface of the primary mirror 340 with respect to the incident light incident surface. The secondary mirror 342 guides part of the incident light transmitted through the primary mirror 340 to the distance measuring unit 330 disposed below. Thereby, when the primary mirror 340 is in the standby position, the distance measuring unit 330 measures the distance to the subject. When the primary mirror 340 is moved to the photographing position, the secondary mirror 342 is also retracted from the optical path of the incident light.

The shutter 320, the optical filter 312 and the image sensor 310 are sequentially arranged behind the main mirror 340 with respect to the incident light from the lens barrel 100. When the shutter 320 is opened, the primary mirror 340 moves to the photographing position immediately before that, so that the incident light goes straight and enters the image sensor 310. As a result, the image formed by the incident light is converted into an electrical signal in the image sensor 310.

In addition, the imaging unit 300 includes a main LCD 396 facing the outside on the rear surface with respect to the lens barrel 100. The main LCD 396 can display various setting information for the imaging unit 300, and can also display an image formed on the imaging element 310 when the primary mirror 340 is moved to the imaging position.

The main control unit 350 comprehensively controls the various operations as described above. In addition, an autofocus mechanism that drives the lens barrel 100 can be formed by referring to the distance information to the subject detected by the distance measuring unit 330 on the imaging unit 300 side. Further, the distance measurement unit 330 can refer to the operation amount of the lens barrel 100 to form a focus aid mechanism.

In this manner, the imaging device 400 having the lens barrel 100 including the buffer cam 252 and the buffer cam follower 219 is formed. Thereby, the effect of the lens barrel 100 can be enjoyed in the imaging apparatus 400. However, the use of the lens barrel 100 is not limited to this, and can be used for a focusing mechanism, a zoom mechanism, and the like in an optical system such as a motion picture camera, binoculars, a microscope, and a surveying instrument.

As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. In addition, it will be apparent to those skilled in the art that various modifications or improvements can be added to the above embodiment. Further, it is apparent from the scope of the claims that the embodiments added with changes or improvements can be included in the technical scope of the present invention.

Claims (20)

A first guide shaft provided along the axial direction of the fixed cylinder on the inner peripheral side of the cylindrical fixed cylinder;
A second guide shaft provided on the outer peripheral side of the fixed cylinder along the axial direction, and at least a portion of the second guide shaft overlapping with the first guide shaft in the longitudinal direction of the first guide shaft;
A first holding member that holds the first lens and has a first engagement portion that engages with the first guide shaft and moves along the first guide shaft;
A second lens that holds the second lens located on the object side of the first lens and has a second engagement portion that engages with the second guide shaft, and moves along the second guide shaft. A holding member,
The moving range of the first engaging portion on the first guide shaft and the moving range of the second engaging portion on the second guide shaft are at least partially overlapped in the axial direction. Lens barrel. The lens barrel according to claim 1,
A lens barrel having a drive member that is disposed between the first guide shaft and the second guide shaft and that drives the first holding member and the second holding member in common. The lens barrel according to claim 2,
The first holding member and the second holding member have a cam follower,
The lens barrel according to claim 1, wherein the driving member is provided with a cam groove to be engaged with the cam follower and is a cam cylinder fitted into the fixed cylinder. In the lens barrel according to any one of claims 1 to 3,
The length with which the first engaging portion is engaged with the first guide shaft is constant regardless of the position of the first engaging portion engaged with the first guide shaft, and The length of the second engaging portion engaged with the second guide shaft is constant regardless of the position of the second engaging portion engaged with the second guide shaft. Lens barrel to be used. In the lens barrel according to any one of claims 1 to 4,
The lens barrel, wherein the first guide shaft and the second guide shaft are fixed to the fixed tube at a plurality of locations of the guide shaft. In the lens barrel according to any one of claims 1 to 5,
At least one of the first guide shaft and the second guide shaft is provided as a pair in parallel with an axial direction perpendicular to the radial direction of the fixed tube. In the lens barrel according to any one of claims 1 to 6,
At least one of the first lens and the first engaging portion in the axial direction and the second lens and the second engaging portion in the axial position are shifted in the optical axis direction. A lens barrel characterized by In the lens barrel according to claim 7,
The lens barrel, wherein the second lens is disposed closer to the object side than the second engaging portion. In the lens barrel according to claim 7,
When the second lens is disposed on the image side of the first lens with respect to the second engagement portion, the first lens is disposed on the image side with respect to the first engagement portion. A lens barrel characterized by that. The lens barrel according to any one of claims 1 to 6,
An imaging apparatus comprising: an imaging unit that captures an image by an optical system including the first lens and the second lens. A lens holding member for holding the lens;
A guide shaft for movably guiding the lens holding member;
A first cam surface that engages with a first cam follower provided on the lens holding member; a second cam surface that can engage with a second cam follower provided on the lens holding member; and the first cam follower and the first cam follower. A cam member that drives the lens holding member along the guide shaft by engagement of one cam surface;
The lens barrel according to claim 1, wherein the cam member has a gap between the second cam follower and the second cam surface. The lens barrel according to claim 11, wherein the lens holding member further includes a fitting portion that fits into the guide shaft. The lens barrel according to claim 12, wherein the first cam follower is disposed closer to the fitting portion than the second cam follower. The lens barrel according to claim 11, wherein the elastic modulus of the first cam follower is higher than the elastic modulus of the second cam follower. The lens barrel according to claim 11, wherein the first cam follower and the second cam follower are arranged at equal intervals along a direction around an optical axis of the lens. The lens barrel according to claim 11, wherein the lens is a first group. A second lens holding member for holding a second lens different from the lens;
A second guide shaft for movably guiding the second lens holding member;
The lens barrel according to claim 11, further comprising: The lens barrel according to claim 17, wherein the cam member drives the second lens holding member along the second guide shaft. A lens barrel according to any one of claims 11 to 18, and
An imaging apparatus comprising: an imaging unit that captures an image by the lens. A lens holding member for holding the lens;
A guide shaft for movably guiding the lens holding member;
A first cam surface that engages with a first cam follower provided on the lens holding member; a second cam surface that can engage with a second cam follower provided on the lens holding member; and the first cam follower and the first cam follower. A cam member that drives the lens holding member along the guide shaft by engagement of one cam surface;
The lens barrel according to claim 1, wherein the cam member has a gap between the second cam follower and the second cam surface.

Images