JP2014021165A - Lens barrel and imaging apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve accuracy in aligning an optical member.SOLUTION: A lens barrel comprises: a hold member having one of a cam groove and a cam pin which engage with each other, and holding an optical member; and a drive member having the other of the cam groove and the cam pin, and configured to drive the hold member in a moving direction parallel to the optical axis of the optical member. The cam groove has a drive section along which the hold member is driven, and a non-drive section communicating with the end of the drive section and extending in a direction orthogonal to the optical axis. In the lens barrel, the cam groove may engage with the cam pin in the non-drive section when the lens barrel is in a collapsed state.

Description

  The present invention relates to a lens barrel and an imaging apparatus.

There is an optical apparatus having a structure in which another frame member holding another lens is further attached to the frame member holding the lens (see Patent Document 1).
[Patent Document 1] JP 2002-333564 A

  When a frame member to be added is fixed, a force applied to the screw may act on the cam, and the alignment of the lens may become unsatisfactory.

  In the first aspect of the present invention, the optical member has one of a cam groove and a cam pin that engage with each other and holds the optical member, and the other of the cam groove and the cam pin, and the optical axis of the optical member A driving member that drives the holding member in a parallel movement direction, and the cam groove communicates with a driving section that drives the holding member and an end of the driving section, and extends in a direction perpendicular to the optical axis. A lens barrel having a section is provided.

  In the second aspect of the present invention, an imaging apparatus including the lens barrel is provided.

  The above summary of the present invention does not enumerate all necessary features of the present invention. Sub-combinations of these feature groups can also be an invention.

1 is a schematic cross-sectional view of a single-lens reflex camera 100. FIG. 2 is a schematic cross-sectional view of a lens unit 200. FIG. 3 is a schematic cross-sectional view orthogonal to the optical axis of the lens unit 200. FIG. It is a typical sectional view of the rear part of lens unit 200. 3 is a schematic development view of a fixed cylinder 201. FIG. FIG. 6 is a schematic development view of a front side moving frame 207. 3 is a schematic development view of a cam cylinder 290. FIG. It is a typical sectional view of the rear part of lens unit 200. It is a typical sectional view of the rear part of lens unit 200.

  Hereinafter, the present invention will be described through embodiments of the invention. The following embodiments do not limit the invention according to the claims. Not all combinations of features described in the following embodiments are essential for the solution of the invention.

  FIG. 1 is a schematic cross-sectional view of a single-lens reflex camera 100. The single-lens reflex camera 100 includes a lens unit 200 and a camera body 300.

  For the purpose of simplifying the description, in the following description, the object side with respect to the lens unit 200 attached to the camera body 300 is described as the front side or the front side of the single-lens reflex camera 100. Further, the side far from the object with respect to the lens unit 200 is referred to as a rear side or a back side in the single-lens reflex camera 100.

  The lens unit 200 includes a first lens group 210, a second lens group 220, a third lens group 230, a fourth lens group 240, a fifth lens group 250, and a sixth lens group arranged along the optical axis X. Has an optical system. The first lens group 210, the second lens group 220, the third lens group 230, the fourth lens group 240, the fifth lens group 250, and the sixth lens group have lens holding frames 212, 222, 232, 242, 252, respectively. 262 individually held.

  The illustrated lens unit 200 is in a retracted state in which the first lens group 210, the second lens group 220, the third lens group 230, the fourth lens group 240, the fifth lens group 250, and the sixth lens group 260 are close to each other. is there. Thereby, the length of the lens unit 200 in the optical axis X direction is shortened, and portability is improved. However, the lens unit 200 in the retracted state cannot be used as an optical device.

  The lens unit 200 includes a lens barrel including a fixed cylinder 201, a zoom ring 202, a rectilinear cylinder 203, a front cylinder 204, a cam cylinder 290, a guide cylinder 206, a front side moving frame 207 and a rear side moving frame 209. The fixed cylinder 201 has a lens side mount 208 at the rear end. The fixed cylinder 201 is coupled to the camera body 300 by coupling the lens side mount unit 208 to the body side mount unit 360 on the front surface of the camera body 300.

  The coupling between the lens side mount portion 208 and the body side mount portion 360 can be released. Therefore, the camera body 300 can be used in combination with another lens unit 200 having the lens side mount portion 208 that conforms to the standard.

  The zoom ring 202 is disposed on the outer peripheral surface of the fixed cylinder 201, and is rotated about the optical axis X of the optical system as a rotation axis by a user operation. The zoom ring 202 in the lens unit 200 is rotated by the user when the lens unit 200 is expanded to cancel the retracted state. The zoom ring 202 is also rotated by the user when the optical system of the lens unit 200 is scaled.

  In the lens unit 200, the lens holding frame 242 that holds the fourth lens group 240 is supported so as to be movable with respect to the front side moving frame 207. The lens holding frame 242 is driven by a feed screw assembly 270 fixed to the front side moving frame 207.

  The feed screw assembly 270 includes a stepping motor 272, a feed screw 274 and a frame 276. The frame 276 integrally supports the stepping motor 272 and the feed screw 274 and is fixed to the front side moving frame 207. The stepping motor 272 drives the feed screw 274 to rotate. The feed screw 274 engages with the lens holding frame 242 via the rack member 278.

  Thereby, the fourth lens group 240 held by the lens holding frame 242 can be moved. When the fourth lens group 240 moves, the focal position of the optical system of the lens unit 200 changes. Therefore, the lens unit 200 can be focused by electrically controlling the stepping motor 272 based on the signal from the camera body 300 side.

  The camera body 300 includes a mirror unit 370 disposed behind the body side mount portion 360. A focusing optical system 380 is disposed below the mirror unit 370. A focusing screen 352 is disposed above the mirror unit 370.

  A pentaprism 354 is disposed further above the focusing screen 352, and a finder optical system 356 is disposed behind the pentaprism 354. The rear end of the viewfinder optical system 356 is exposed as a viewfinder 350 on the back surface of the camera body 300.

  Behind the mirror unit 370, a shutter unit 310, a low-pass filter 332, an image sensor 330, a substrate 320, and a display unit 340 are sequentially arranged. A display unit 340 formed by a liquid crystal display panel or the like appears on the back surface of the camera body 300. A control unit 322, an image processing unit 324, and the like are mounted on the substrate 320.

  The mirror unit 370 includes a main mirror 371 and a sub mirror 374. The main mirror 371 is supported by a main mirror holding portion 372 that is pivotally supported by a main mirror rotating shaft 373.

  The sub mirror 374 is supported by a sub mirror holding portion 375 that is pivotally supported by a sub mirror rotating shaft 376. The sub mirror holding unit 375 rotates with respect to the main mirror holding unit 372. Therefore, when the main mirror holding part 372 rotates, the sub mirror holding part 375 is also displaced together with the main mirror holding part 372.

  When the front end of the main mirror holding portion 372 is lowered, the main mirror 371 is positioned obliquely on the incident light beam incident from the lens unit 200. When the main mirror holding part 372 moves up, the main mirror 371 retracts to a position avoiding the incident light beam.

  When the main mirror 371 is positioned on the incident light beam, the incident light beam incident through the lens unit 200 is reflected by the main mirror 371 and guided to the focusing screen 352. The focusing screen 352 is disposed at a position conjugate with the optical system of the lens unit 200, and visualizes an image formed by the optical system of the lens unit 200.

  The image on the focusing screen 352 is observed from the viewfinder 350 through the pentaprism 354 and the viewfinder optical system 356. Here, an erect image can be observed from the viewfinder 350 by observing the image through the pentaprism 354.

  The photometric sensor 390 is disposed above the finder optical system 356 and receives a part of the branched incident light beam. The photometric sensor 390 detects the subject brightness and causes the control unit 322 to calculate an exposure condition that is a part of the photographing condition.

  The main mirror 371 has a half mirror region that transmits a part of the incident light beam. The sub mirror 374 reflects a part of the incident light beam incident from the half mirror region toward the focusing optical system 380. The focusing optical system 380 guides a part of the incident incident light beam to the focus detection sensor 382. Thereby, the control unit 322 determines the target position of the lens that moves when the optical system of the lens unit 200 is focused.

  When the release button is half-pressed in the single-lens reflex camera 100 including the lens unit 200 and the camera body 300 as described above, the focus detection sensor 382 and the photometric sensor 390 are enabled, and a subject image can be taken under appropriate shooting conditions. It becomes a state.

  Next, when the release button is fully pressed, the main mirror 371 and the sub mirror 374 move to the retracted position, and the shutter unit 310 is opened. Thereby, the incident light beam incident from the lens unit 200 passes through the low-pass filter 332 and enters the image sensor 330. In this way, an image formed on the imaging surface of the imaging element 330 is captured by the optical system of the lens unit 200.

  FIG. 2 is a cross-sectional view of the lens unit 200. In FIG. 2, a cross section of the lens unit 200 that is scaled to the wide angle side is shown on the upper side of the optical axis X in the drawing. Further, in FIG. 2, a cross section of the lens unit 200 that is zoomed to the telephoto side is shown below the optical axis X in the drawing.

  In FIG. 2, the same elements as those in FIG. However, although FIG. 2 is common to FIG. 1 in that it is a cross section including the optical axis X, it shows a cross section different from FIG. Therefore, some of the common elements are drawn in a shape different from that in FIG.

  In the lens unit 200, the rectilinear cylinder 203 engages with the zoom ring 202 at the lead portion 281. Since the rectilinear cylinder 203 is suppressed from rotating with respect to the fixed cylinder 201, when the zoom ring 202 is rotated, a driving force that translates in the direction of the optical axis X is received from the zoom ring 202.

  The cam cylinder 290 engages in the vicinity of the rear end of the rectilinear cylinder 203 by a bayonet claw 286 disposed in the vicinity of the rear end of itself. Since the bayonet claw 286 engages with the bayonet groove extending in the circumferential direction on the inner surface of the rectilinear cylinder 203, the cam cylinder 290 can rotate around the optical axis X. However, when the rectilinear cylinder 203 translates in the optical axis X direction, the cam cylinder 290 also moves in the optical axis direction along with the rectilinear cylinder 203. In other words, the cam cylinder 290 and the rectilinear cylinder 203 are engaged only in the optical axis X direction.

  The cam cylinder 290 engages with a rectilinear groove 405 provided on the inner surface of the zoom ring 202 in parallel with the optical axis X through a connecting pin 285 fixed to the outer peripheral surface of the cam cylinder 290. Thereby, when the zoom ring 202 is rotated, the cam barrel 290 also rotates.

  As described above, when the zoom ring 202 is rotated, the rectilinear cylinder 203 translates in the optical axis X direction, and the cam cylinder 290 translates along with the rectilinear cylinder 203. Therefore, when the zoom ring 202 is rotated, the cam barrel 290 translates in the direction of the optical axis X while rotating around the optical axis X.

  The guide tube 206 is located inside the cam tube 290 and is coupled to the fixed tube 201 and fixed. Therefore, when the zoom ring 202 is rotated, the rectilinear cylinder 203 and the cam cylinder 290 also translate relative to the guide cylinder 206. Since the guide tube 206 extends toward the front end side of the lens unit 200 in the direction of the optical axis X, the guide tube 206 supports the cam tube 290 from the inner surface side and is associated with a key 287 provided at the rear end of the rectilinear tube 203. The rectilinear groove 288 is combined to restrict the rotation of the rectilinear cylinder 203.

  The front tube 204 supports the lens holding frame 212 of the first lens group 210 at the tip. Further, the front tube 204 is supported from both sides by engaging with the rectilinear tube 203 and the cam tube 290 by the cam pins 282 and the like. Therefore, when the rectilinear cylinder 203 and the cam cylinder 290 translate in the optical axis X direction, the leading cylinder 204 also translates in the optical axis X direction.

  Further, when the zoom ring 202 is rotated, the leading cylinder 204 is driven between the rectilinear cylinder 203 that translates without rotating and the cam cylinder 290 that translates while rotating, and the rectilinear cylinder 203 and the cam cylinder. Translate to 290 as well. As a result, the first lens group 210 held at the tip of the front tube 204 is largely extended forward from the fixed tube 201.

  The front-side moving frame 207 is disposed inside the cam cylinder 290 and the guide cylinder 206 and supports the lens holding frames 232 and 252 that hold the third lens group 230 and the fifth lens group 250 together. The rear moving frame 209 is disposed further inside the front moving frame 207 and supports the lens holding frame 262 that holds the sixth lens group 260. The front-side moving frame 207 and the rear-side moving frame 209 are engaged with the cam cylinder 290 and moved in the optical axis X direction when the zoom ring 202 is rotated. In the figure, a cam pin 264 for engaging the rear moving frame 209 with the cam cylinder 290 is visible.

  The sixth lens group 260 further includes an additional lens group 261 arranged on the back side of the lens holding frame 262. The additional lens group 261 is held by an additional lens holding frame 263, and the additional lens holding frame 263 is fixed to the back surface of the lens holding frame 262.

  When the zoom ring 202 is rotated in the lens unit 200 as described above, the first lens group 210, the second lens group 220, the third lens group 230, the fifth lens group 250, and the sixth lens group 260 are fixed. Move relative to the tube 201. Thereby, the magnification of the optical system formed in the lens unit 200 changes. In addition, when the zoom ring 202 is rotated beyond the range of zooming of the lens unit 200, the lens unit 200 is contracted into a retracted state.

  FIG. 3 is a schematic cross-sectional view showing a cross section orthogonal to the optical axis X of the lens unit 200. Elements common to those in FIGS. 1 and 2 are denoted by the same reference numerals, and redundant description is omitted. In the lens unit 200, the zoom ring 202, the fixed cylinder 201, the front side moving frame 207, the cam cylinder 290 and the rear side moving frame 209 are arranged coaxially with respect to the optical axis X, and mutually around the optical axis X. Rotate.

  In the lens unit 200, the connecting pin 285 fixed to the cam cylinder 290 engages with a rectilinear groove 405 disposed on the inner surface of the zoom ring 202. As a result, the cam cylinder 290 rotates together with the zoom ring 202. Further, the cam pin 292 provided on the outer peripheral surface of the cam cylinder 290 engages with the cam groove 402 disposed on the inner surface of the fixed cylinder 201.

  Furthermore, the cam cylinder 290 has a cam pin 296 that protrudes to the outer peripheral surface, and a cam groove 294 provided on the inner peripheral surface. The cam pin 296 engages with a cam groove 256 formed on the inner peripheral surface of the front side moving frame 207. The cam groove 294 engages with a cam pin 264 fixed to the outer peripheral surface of the rear moving frame 209.

  The rectilinear projection 259 of the front side moving frame 207 engages with the rectilinear groove 401 disposed on the inner surface of the fixed cylinder 201. The rectilinear protrusion 269 of the rear moving frame 209 engages with a rectilinear groove 404 disposed on the inner surface of the fixed cylinder 201. Thereby, the rotation of the front side moving frame 207 and the rear side moving frame 209 with respect to the fixed cylinder 201 is restricted.

  Three of the cam pins 264, 292, 296, the connecting pin 285 and the cam grooves 256, 294, 402, the rectilinear protrusions 259, 269, and the rectilinear grooves 401, 404, 405 are approximately three in the circumferential direction of the lens unit 200. Arranged at equal intervals. As a result, the cam cylinder 290, the front side moving frame 207, the cam cylinder 290, and the rear side moving frame 209 are driven in a balanced manner in the circumferential direction of the lens unit 200 and are prevented from being inclined with respect to the optical axis X. .

  In the cam cylinder 290, the connecting pin 285 is disposed in the vicinity of the cam pin 292 in the circumferential direction of the lens unit 200. Thereby, when the connecting pin 285 is driven, it is possible to suppress the inclination of the cam cylinder 290 with respect to the optical axis X caused by the displacement of the position with the cam pin 292. Similarly, the cam pin 264 is preferably disposed in the vicinity of the rectilinear protrusion 269 in the circumferential direction of the lens unit 200.

  FIG. 4 is a schematic diagram showing a partial cross section of the lens unit 200 in the retracted state. Although the shape is simplified for the purpose of simplifying the drawing, the same reference numerals are assigned to the same elements as those in FIGS. 1 and 2 to omit redundant description.

  As shown in FIG. 3, the cam pins 264, 292, 296, the connecting pin 285 and the cam grooves 256, 294, 402, the rectilinear protrusions 259, 269 and the rectilinear grooves 401, 404, 405 are the lens unit 200. Are arranged at different positions in the circumferential direction. Thus, these elements do not all appear in a single cross section. However, FIG. 4 shows these elements together for the purpose of showing the positional relationship of each element in the optical X direction.

  In the lens unit 200, the rectilinear protrusion 259 of the front moving frame 207 and the rectilinear protrusion 269 of the rear moving frame 209 individually engage with the rectilinear grooves 401 and 404 that are independent from each other. Thus, when the lens unit 200 is in the retracted state, the rear end portions of the front side moving frame 207 and the rear side moving frame 209 can overlap in a cross section including the optical axis X. Therefore, the rear end of the front side moving frame 207 and the rear side moving frame 209 can be retracted until they abut against the rear surface of the fixed cylinder 201, and the length of the lens unit 200 in the optical axis X direction can be shortened.

  The lens holding frame 262 that holds the sixth lens group 260 has a locking hole 267. The locking hole 267 is disposed on the back surface of the lens holding frame 262 and is recessed in a direction parallel to the optical axis X. Further, the locking hole 267 has a tapered cross-sectional shape in which the inner diameter increases as it approaches the back surface of the lens holding frame 262. Thereby, a tool can be easily inserted into the locking hole 267 from the rear of the lens unit 200.

  FIG. 5 is a development view of the fixed cylinder 201 and shows a layout of the rectilinear grooves 401 and 404 and the cam groove 402 on the inner surface of the fixed cylinder 201. Elements that are the same as those in FIG. 4 are given the same reference numerals, and redundant descriptions are omitted. FIG. 5 shows one of the three rectilinear grooves 401, 404 and the cam groove 402 provided in each case.

  In the fixed cylinder 201, the straight grooves 401 and 404 are arranged in a direction parallel to the optical axis X of the lens unit 200. Therefore, the rectilinear protrusions 259 and 269 engaged with the rectilinear grooves 401 and 404 are restricted from being displaced in the circumferential direction of the lens unit 200 while being allowed to be displaced in the optical axis X direction.

  The cam groove 402 includes a built-in section 297, a driving section 298, and a non-driving section 299. The built-in section 297 extends in parallel with the optical axis X, and one end opens at the end surface of the fixed cylinder 201. The other end of the built-in section 297 communicates with one end of the drive section 298. Accordingly, the cam pin 292 that engages with the cam groove 402 can be incorporated into the drive section 298 of the cam groove 402 from the optical axis X direction.

  The drive section 298 has a profile inclined with respect to the optical axis X between the built-in section 297 and the non-drive section 299. Therefore, when the cam pin 292 is displaced with respect to the cam groove 402 in the drive section 298, the cam cylinder 290 moves in the optical axis X direction in the lens unit 200.

  The drive section 298 includes a scaling section adjacent to the built-in section 297. When the cam pin 292 is displaced with respect to the cam groove 402 in the zooming section, the magnification of the lens unit 200 changes from the telephoto end to the wide angle end.

  When the cam pin 292 is displaced beyond the wide-angle end in the drive section of the cam groove 402, the lens unit 200 starts to shrink toward the retracted state. Since the non-drive section 299 is arranged following the drive section 298 of the cam groove 402, when the cam pin 292 passes through the retracted position in the cam groove 402 where the lens unit 200 is in the retracted state, the cam pin 292 is in the non-drive section 299. Engages with the cam groove 402.

  In the non-driving section 299 provided in communication with the other end of the driving section 298, the cam groove 402 extends in a direction orthogonal to the optical axis X. Therefore, when the cam pin 292 is engaged with the non-driving section 299 of the cam groove 402, the cam cylinder 290 is not driven in the optical axis X direction even if it rotates with respect to the fixed cylinder 201. Further, even if the cam pin 292 is displaced in the optical axis X direction and the cam groove 402 is pushed in the optical axis X direction from the inside, no force for rotating the cam cylinder 290 is generated.

  In the above structure, when the cam pin 292 is provided in the fixed cylinder 201 and the cam groove 402 is provided in the cam cylinder 290, a drive mechanism having the same function as the above example can be formed. Also, when the rectilinear groove 404 is provided in the rear moving frame 209 and the rectilinear protrusion 269 is provided in the fixed cylinder 201, a drive mechanism having the same function as the above example can be formed.

Further, as described above, the cam groove 402 does not contribute to driving of the cam pin 292 in the non-drive section 299. For this reason, in the section from the cam pin 292 passing through the zooming section to the retracted position, the inclination of the cam groove 402 increases as shown by the angle θ ₁ in the drawing, and the constant required for the cam cylinder 290 is obtained. The effective rotation amount of the cam cylinder 290 decreases with respect to the drive amount.

  FIG. 6 is a development view of the front side moving frame 207, and shows a layout of the rectilinear protrusions 259 and the cam grooves 256 on the outer surface of the front side moving frame 207. Elements that are the same as those in FIG. 5 are given the same reference numerals, and redundant description is omitted. In addition, FIG. 6 shows one each of the rectilinear protrusions 259 and the cam grooves 256 provided by three each.

  In the front side moving frame 207, the cam groove 256 includes a built-in section 297, a driving section 298, and a non-driving section 299. The built-in section 297 extends in parallel with the optical axis X, and one end opens at the end surface of the front side moving frame 207. The other end of the built-in section 297 communicates with one end of the drive section 298. Thereby, the cam pin 296 engaged with the cam groove 256 can be incorporated into the drive section 298 of the cam groove 256 from the optical axis X direction.

  The drive section 298 has a profile inclined with respect to the optical axis X between the built-in section 297 and the non-drive section 299. Therefore, when the cam pin 296 is displaced with respect to the cam groove 256 in the drive section 298, the front side moving frame 207 moves in the optical axis X direction with respect to the cam cylinder 290 in the lens unit 200.

  The drive section 298 includes a scaling section adjacent to the built-in section 297. When the cam pin 296 is displaced with respect to the cam groove 256 in the zooming section, the magnification of the lens unit 200 changes from the telephoto end to the wide angle end.

When the cam pin 296 is displaced beyond the wide-angle end in the drive section of the cam groove 256, the lens unit 200 starts to shrink toward the retracted state. The cam groove 256 is not provided with a non-drive section 299. Therefore, even in the section where the cam pin 296 passes through the zooming section and reaches the retracted position, the inclination of the cam groove 256 does not increase as shown by the angle θ ₂ in the figure, and the front moving frame 207 is required. For a certain driving amount, the load on the cam pin 296 is small.

  In the above structure, even when the cam pin 296 is provided in the front side moving frame 207 and the cam groove 256 is provided in the cam cylinder 290, a drive mechanism having the same function as the above example can be formed. Further, when the rectilinear groove 401 is provided in the front side moving frame 207 and the rectilinear protrusion 259 is provided in the fixed cylinder 201, a drive mechanism having the same function as the above example can be formed.

  FIG. 7 is a development view of the cam cylinder 290, and shows the layout of the cam pins 264 and 292 on the outer surface of the cam cylinder 290 and the layout of the cam groove 294 on the inner surface of the cam cylinder 290. Elements that are the same as those in FIG. 5 are given the same reference numerals, and redundant description is omitted. Of the cam pins 292 and 296 and the cam grooves 294 that are provided in three, one is shown in FIG.

  In the cam cylinder 290, the cam groove 294 includes a built-in section 297, a drive section 298 and a non-drive section 299. The built-in section 297 extends in parallel with the optical axis X, and one end opens at the end surface of the cam cylinder 290. The other end of the built-in section 297 communicates with one end of the drive section 298. Thereby, the cam pin 264 engaged with the cam groove 294 can be incorporated into the drive section 298 of the cam groove 294 from the optical axis X direction.

  The drive section 298 has a profile inclined with respect to the optical axis X between the built-in section 297 and the non-drive section 299. Therefore, when the cam pin 264 is displaced with respect to the cam groove 294 in the drive section 298, the rear side moving frame 209 moves in the optical axis X direction with respect to the cam cylinder 290 in the lens unit 200.

  The drive section 298 includes a scaling section adjacent to the built-in section 297. When the cam pin 264 is displaced with respect to the cam groove 294 in the zooming section, the magnification of the lens unit 200 changes from the telephoto end to the wide angle end.

  When the cam pin 264 is displaced beyond the wide angle end in the drive section of the cam groove 294, the lens unit 200 starts to shrink toward the retracted state. When the cam pin 264 reaches the retracted position in the cam groove 294, the cam groove 294 becomes a non-drive section 299. The non-drive section 299 is formed in a direction orthogonal to the optical axis X. Therefore, when the cam pin 264 is displaced in the non-driving section 299, the rear moving frame 209 does not move in the optical axis X direction.

In the above structure, even when the cam pin 264 is provided in the cam cylinder 290 and the cam groove 294 is provided in the rear moving frame 209, a drive mechanism having the same function as the above example can be formed. Further, as described above, in the non-drive section 299, the cam groove 294 does not contribute to driving of the cam pin 264. Therefore, in the section where the cam pin 264 reaches from leaves the zooming section to the collapsed position, the inclination of the cam groove 294 as shown by the angle theta ₃ in the figure increases, it is required for the rear movable frame 209 The effective drive amount of the cam cylinder 290 decreases with respect to a certain drive amount.

  FIG. 8 is a schematic cross-sectional view showing the state in which the lens unit 200 is expanded in the cross section shown in FIG. Although the shape is simplified for the sake of brevity, the same reference numerals are given to the same elements as those up to FIG.

  When the zoom ring 202 is rotated in the lens unit 200, the cam cylinder 290 engaged by the connecting pin 285 also rotates together. The cam cylinder 290 also translates in the optical axis X direction with respect to the fixed cylinder 201 according to the profile of the cam groove 402 of the fixed cylinder 201 with which the cam pin 292 is engaged.

  The front side moving frame 207 is restricted from rotating by engaging the rectilinear protrusions 259 with the rectilinear grooves 401 of the fixed cylinder 201. Therefore, when the cam cylinder 290 rotates and translates, the front moving frame 207 is driven according to the profile of the cam groove 256 that engages with the cam pin 296 provided on the outer surface of the cam cylinder 290 and translates in the optical axis X direction. To do.

  Further, as described above, since the cam cylinder 290 itself translates in the optical axis X direction, the front-side moving frame 207 includes the fixed cylinder 201 of the cam cylinder 290 in addition to the amount of movement of the front-side moving frame 207 with respect to the cam cylinder 290. The amount of movement with respect to is also moved. Thereby, the lens unit 200 can move the fifth lens group 250 greatly, and the change rate of magnification can be increased.

  The rear movement frame 209 is restricted from rotating by engaging the rectilinear protrusion 269 with the rectilinear groove 404 of the fixed cylinder 201. Therefore, when the cam cylinder 290 rotates and translates, the rear moving frame 209 translates in the optical axis X direction by driving the cam pin 264 according to the profile of the cam groove 294 formed on the inner surface of the cam cylinder 290.

  Furthermore, the front side moving frame 207 engages with the cam pin 296 of the cam cylinder 290 in a cam groove 256 formed on the inner surface. Thereby, when the cam cylinder 290 rotates and translates, the front-side moving frame 207 is driven with a driving amount that combines the translation of the cam cylinder 290 and the driving by the profile of the cam groove 256.

  Further, as described above, since the cam cylinder 290 itself translates in the optical axis X direction, the rear movement frame 209 has a fixed cylinder 201 of the cam cylinder 290 in addition to the amount of movement of the rear movement frame 209 relative to the cam cylinder 290. The amount of movement with respect to is also moved. Thereby, the lens unit 200 can move the sixth lens group 260 greatly.

  FIG. 9 is a schematic cross-sectional view showing a part of the assembly process of the lens unit 200 and a process of attaching the additional lens holding frame 263 holding the additional lens group 261 in the same cross section as FIG. Although the shape is simplified for the purpose of simplifying the drawing, the same reference numerals are given to the elements common to those shown in FIG.

  In the assembly of the lens unit 200, the additional lens holding frame 263 that holds the additional lens group 261 is a lens from the rear of the lens unit 200 after the lens holding frame 262 that holds the sixth lens group 260 is assembled in the fixed cylinder 201. Attached to the holding frame 262. The additional lens holding frame 263 is formed by first aligning the additional lens group 261 with another optical member already formed in the fixed cylinder 201 and then tightening the set screw 265 into the screw hole 266. Fix at the position after alignment.

  Here, the additional lens holding frame 263 has an insertion hole 268. The insertion hole passes through the additional lens holding frame 263 in a direction parallel to the optical axis of the additional lens group 261. Further, the insertion hole 268 has an inner diameter larger than the outer diameter of the set screw 265. Accordingly, the additional lens holding frame 263 can be moved and aligned in the direction intersecting the optical axis with the tip of the set screw 265 slightly screwed into the screw hole 266.

  Further, when the set screw 265 is tightened into the screw hole 266, the force with which the fastening tool 407 presses the set screw 265 may act on the rear moving frame 209 through the lens holding frame 262. In such a case, if the cam pin 264 of the rear moving frame 209 is engaged with the drive section 298 of the cam groove 294 of the cam cylinder 290, the cam cylinder 290 may be driven and rotated. When the cam cylinder 290 rotates, the characteristics of the optical system of the lens unit 200 change, so that the additional lens 261 cannot be effectively adjusted.

  However, when the lens unit 200 is in the retracted state, the cam pin 264 of the rear moving frame 209 is engaged with the non-drive section 299 of the cam groove 294 of the cam cylinder 290. In the non-driving section 299, the cam groove 294 extends in a direction orthogonal to the optical axis X. Therefore, even if the cam pin 264 pushes the cam groove 294 in the optical axis direction, the action of rotating the cam cylinder 290 does not occur.

  When the lens unit 200 is in the retracted state, the cam pin 292 of the cam cylinder 290 is engaged with the non-drive section 299 also in the cam groove 402 provided in the fixed cylinder 201. Therefore, when the force that pushes the lens holding frame 262 in the direction of the optical axis X acts on the cam cylinder 290 through the rear movement frame 209, the operation of rotating the cam cylinder 290 by the cam groove 402 of the fixed cylinder 201 is also prevented. .

  Further, in the lens unit 200, the lens holding frame 262 has a locking hole 267. By inserting the tip of the locking tool 406 into the locking hole 267, the rotation of the lens holding frame 262 around the optical axis X can be locked. Therefore, when the set screw 265 for fixing the additional lens holding frame 263 is fastened, the sixth lens group can be more reliably controlled by inserting the locking tool 406 into the locking hole 267 and restricting the rotation of the lens holding frame 262. 260 and the like can be prevented from moving in the optical axis X direction.

  The tip of the locking tool 406 is formed into a tapered shape so that insertion into the locking hole 267 can be facilitated. Further, if the cam cylinder 290 is prevented from rotating with respect to the fixed cylinder 201, the force that pushes the cam cylinder 290 does not act on the front side moving frame 207. Therefore, the non-driving section 299 may not be provided in the cam groove 256 of the front side moving frame 207.

  As described above, in the lens unit 200, the force generated when the additional lens holding frame 263 is attached to the lens holding frame 262 is suppressed from rotating the cam cylinder 290. Therefore, the additional lens group 261 can be aligned with high accuracy. Even if the additional lens holding frame 263 that holds the aligned additional lens group 261 is fixed by the set screw 265, the alignment of the additional lens group 261 is prevented from being shifted. Therefore, the lens unit 200 with high optical performance can be manufactured.

  The single-lens reflex camera 100 including the replaceable lens unit 200 has been described above as an example, but the above-described structure can be applied even to a non-flex camera that does not include a quick return mirror. In addition to a camera in which the lens unit 200 and the camera body 300 are integrally formed, the above-described structure can be applied to a telescope, a surveying instrument, a microscope, and the like provided with an optical member driven by a cam mechanism.

  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. It will be apparent to those skilled in the art that various modifications or improvements can be added to the above-described embodiment. It is apparent from the scope of the claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention.

100 single-lens reflex camera, 200 lens unit, 201 fixed cylinder, 202 zoom ring, 203 rectilinear cylinder, 204 front cylinder, 206 guide cylinder, 207 front side moving frame, 209 rear side moving frame, 208 lens side mount part, 210 1st Lens group, 212, 222, 232, 232, 242, 252, 262 Lens holding frame, 220 Second lens group, 230 Third lens group, 240 Fourth lens group, 250 Fifth lens group, 256, 294, 402 Cam Groove, 259, 269 Straight projection, 260 Sixth lens group, 261 Additional lens group, 263 Additional lens holding frame, 264, 282, 292, 296 Cam pin, 265 Set screw, 266 Screw hole, 267 Lock hole, 268 Insertion Hole, 298 Drive section, 299 Non-drive section, 270 Lead screw assembly, 272 Ping motor, 274 feed screw, 276 frame, 278 rack member, 285 connecting pin, 286 bayonet claw, 287 key, 288, 401, 404, 405 straight groove, 290 cam cylinder, 297 installation section, 298 drive section, 299 non-drive section , 300 camera body, 310 shutter unit, 320 substrate, 322 control unit, 324 image processing unit, 330 imaging device, 332 low-pass filter, 340 display unit, 350 finder, 352 focusing screen, 354 pentaprism, 356 finder optical system, 360 Body side mount part, 370 mirror unit, 371 main mirror, 372 main mirror holding part, 373 main mirror rotating shaft, 374 sub mirror, 375 sub mirror holding part, 37 Submirror pivot shaft, 380 focusing optics, 382 focus detection sensor 390 photometer, 406 locking tool, 407 the fastening tool

Claims (6)

A holding member having either one of a cam groove and a cam pin that engage with each other and holding an optical member;
A driving member that has the other of the cam groove and the cam pin and drives the holding member in a moving direction parallel to the optical axis of the optical member;
The cam groove has a driving section for driving the holding member, and a non-driving section that communicates with an end of the driving section and extends in a direction orthogonal to the optical axis.   The lens barrel according to claim 1, wherein the cam groove is engaged with the cam pin in the non-driving section when the lens barrel is in a retracted state.   The lens barrel according to claim 1, further comprising another holding member that is fixed to the holding member while holding another optical member different from the optical member.   The lens barrel according to claim 3, wherein the other holding member is fixed to the holding member by a fixing member that is rotated around a rotation axis that is parallel to the optical axis with respect to the holding member.   The lens barrel according to claim 4, wherein the holding member has a locking portion that locks when the holding member is restricted from rotating around the optical axis.   An imaging device comprising the lens barrel according to any one of claims 1 to 5.

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