JP5248670B2 - Lens barrel linear guide mechanism - Google Patents

Description

  The present invention relates to a linear guide mechanism that constitutes a lens barrel.

  In a lens barrel, a member that holds an optical element such as a lens group is moved in the optical axis direction by a combination of a rectilinear guide mechanism that performs linear guide in the optical axis direction and a rotating ring such as a cam ring. It is generally done.

JP 2004-151710 A

  The straight guide mechanism in the lens barrel is provided with a portion such as a long groove having a guide surface extending in the optical axis direction or a guide key on a straight guide member (for example, a straight guide ring) on the side that performs straight guide, and receives a straight guide. It is a general structure that a linearly moving member (for example, a linearly moving ring) is provided with a sliding portion that slidably contacts the guide surface. The upper limit of the amount of movement of the rectilinear movement member is determined by the length of the guide surface on the rectilinear guide member, and the length of the guide surface is limited by the length of the rectilinear guide member in the optical axis direction. In other words, since the amount of movement beyond the length of the linear guide member in the optical axis direction cannot be given to the linear movement member, the amount of movement of the linear movement member and the compactness of the linear guide member in the optical axis direction have a trade-off relationship. there were. For example, if an attempt is made to increase the movement distance of each lens group in order to achieve a high zoom ratio of the zoom lens, the size of the linear guide member that performs linear guide to the lens group becomes large (long), and the lens mirror It is constrained to make the cylinder compact, particularly to reduce the thickness in the optical axis direction. On the other hand, a small (short) linear guide member having a small size in the optical axis direction cannot give a large amount of movement.

  The present invention is based on the above-mentioned problem awareness, and linearly guides the lens barrel capable of giving a large amount of movement in the optical axis direction to the linearly moving member while reducing the size of the linearly guided member in the optical axis direction. The purpose is to obtain the mechanism.

  The present invention focuses on the fact that there are a plurality of members that are not rotated in the lens barrel, and the linear guide mechanism is configured across these members, thereby limiting the length of the individual linear guide members in the optical axis direction. This is based on the idea that the amount of straight travel can be set. That is, according to the present invention, in a lens barrel that linearly moves a linearly moving member that holds an optical element in the optical axis direction by rotation of a rotating ring, the linearly moving member is divided into a plurality of different moving ranges in the optical axis direction relative to one linearly moving member. A rectilinear guide mechanism is constituted by a plurality of partial rectilinear guide members that perform rectilinear guidance, and the moving ranges of the rectilinear guides with respect to one rectilinear moving member by the plural partial rectilinear guide members have mutually overlapping portions, It is characterized in that switching of the rectilinear guide between a plurality of partial rectilinear guide members for one rectilinear moving member is performed.

  In a lens barrel of a type that can be operated in a shooting state and a storage state in which shooting is not performed, one linear movement member is provided by a first partial rectilinear guide member in the shooting state and a second partial rectilinear guide member in the storage state. In the middle of the transition from the storage state of the lens barrel to the photographing state, the linear guide by the second partial linear guide member for the one linearly moving member is canceled during the transition from the retracted state of the lens barrel to the photographing state. It is preferable that the partial rectilinear guide member starts the rectilinear guide. At this time, it is possible to set the timing at which the linear guide by the first partial linear guide member is started earlier than the timing at which the linear guide by the second partial linear guide member is released with respect to one linearly moving member. preferable.

  When the optical system of the lens barrel is a zoom optical system, the first partial rectilinear guide member has one rectilinear moving member in the entire zoom photographing region moving range from the wide end to the tele end of the zoom optical system. It is preferable to guide straight in the optical axis direction. As described above, the optical element can be guided with high accuracy by keeping the members in charge of the straight-ahead guidance consistent in the photographing state (zoom photographing region).

  The rotating ring that applies a moving force in the optical axis direction to one linearly moving member guided linearly by the first and second partial linearly guiding members is, for example, a cam engaged with a cam follower provided on the linearly moving member. A cam ring having a groove (first cam groove).

  In this case, the first partial rectilinear guide member may be coupled to the cam ring so as to be relatively rotatable and to be relatively rotatable in the optical axis direction. When the cam ring rotates, the first partial rectilinear guide member integrated with the cam ring in the optical axis direction and one linearly moving member that moves in the optical axis direction according to the cam groove (first cam groove) As a result, the relative position in the optical axis direction is changed, so that the first partial rectilinear guide member can be switched between a state in which one rectilinearly moving member is rectilinearly guided and a state in which the rectilinear guidance is released.

  Further, when the lens barrel changes from the housed state to the photographing state, the cam ring itself may move forward in the optical axis direction while rotating with respect to the fixed ring. In this case, it is preferable that the first partial rectilinear guide member whose position in the optical axis direction changes with the cam ring is linearly guided in the optical axis direction by the rectilinear guide portion provided in the fixed ring.

  The cam ring is provided with a second cam groove having a locus different from that of the first cam groove with which the cam follower of the linearly moving member is engaged, and the second cam groove is used to form the second partial linear guide member. The position in the optical axis direction can be controlled. The second partial rectilinear guide member holds an optical element different from the one rectilinear moving member described above, and linearly moves in the optical axis direction along a different path from the one rectilinear moving member according to the rotation of the cam ring. Is done. Thereby, the relative position in the optical axis direction changes between the one linearly moving member and the second partial linearly guiding member, and the second partial linearly guiding member linearly guides the one linearly moving member, and It is possible to switch to a state in which the straight guidance is canceled.

  When the second partial rectilinear guide member itself is movable in the optical axis direction in this way, the second rectilinear guide member that receives the rectilinear guide in the optical axis direction by the rectilinear guide portion provided in the fixed ring is used to provide the second partial rectilinear guide member itself. It is preferable that the partial rectilinear guide member be guided linearly in the optical axis direction.

  As an example, each of the one rectilinear moving member and the first partial rectilinear guide member can be an appearance ring of a lens barrel that changes the amount of superposition according to the rotation of the cam ring.

  As a specific rectilinear guide structure in the rectilinear guide mechanism of the present invention, each of the plurality of partial rectilinear guide members is formed with a rectilinear guide groove having at least one end portion opened in the optical axis direction and extending in the optical axis direction. The moving member is preferably provided with a plurality of kinds of rectilinear guide keys that are inserted into and removed from the rectilinear guide grooves of the plurality of partial rectilinear guide members through the opening end.

  In this case, by forming the opening end of the rectilinear guide groove as a tapered opening that gradually increases the groove width, the rectilinear guide key that is out of the rectilinear guide groove can be inserted smoothly. Alternatively, the same effect can be obtained by forming a tapered tip end portion that gradually decreases in width toward the tip end at the insertion end portion of the rectilinear guide key into the straight guide groove.

  According to the present invention, since it is possible to give the linear movement member a moving amount in the optical axis direction that is larger than the length in the optical axis direction of each partial linear guide member, it is possible to reduce the size of the linear guide member in the optical axis direction. In this manner, a linear guide mechanism for the lens barrel capable of giving a large amount of movement in the optical axis direction to the linearly moving member can be obtained.

It is sectional drawing in the zoom imaging | photography area | region (an upper half part is a wide end and a lower half part is a tele end) which shows one Embodiment of the zoom lens barrel provided with the linear guide mechanism by this invention. It is sectional drawing in the accommodation state of the zoom lens barrel. It is a disassembled perspective view of the state which removed the movable lens block from the housing of the zoom lens barrel. It is a disassembled perspective view of a movable lens block. It is a disassembled perspective view of a 2nd delivery cylinder and the 1st lens group supported by it. It is a back perspective view of the 2nd feeding cylinder. It is a front perspective view of a 1st delivery cylinder. It is a disassembled perspective view of a 2nd lens group moving frame and the 2nd lens group supported by it. It is an expansion | deployment top view which shows a part of 2nd delivery cylinder transparently. It is an expansion | deployment top view of a 1st delivery cylinder. It is a development top view of the 2nd group lens movement frame. FIG. 6 is a developed plan view showing a rectilinear guide relationship between a second feeding cylinder, a first feeding cylinder, and a second group lens moving frame when the zoom lens barrel is stored. It is an expansion | deployment top view which shows delivery (switching) of the rectilinear guidance in the same rectilinear guidance relationship. FIG. 5 is a developed plan view showing the straight-ahead guide relationship when the zoom lens barrel is in a zoom photographing region (wide end). It is a fragmentary perspective view which shows the state which the 2nd group lens movement frame is guiding the 2nd delivery cylinder straightly. It is a fragmentary perspective view which shows the state by which the straight advance guidance of the 2nd delivery cylinder by the 2nd group lens moving frame was cancelled | released.

  1 and 2 show an embodiment of a zoom lens barrel ZL provided with a linear guide mechanism according to the present invention. The imaging optical system of the zoom lens barrel ZL includes a first lens group (optical element) LG1, a second lens group (another optical element) LG2, a third lens group LG3, and a low-pass filter 25 in order from the object (subject) side. And an image sensor 26. In the following description, the optical axis direction means a direction parallel to the optical axis O of the photographing optical system, the front means front in the optical axis direction (subject side), and the rear means rear in the optical axis direction (image). Surface side).

  The low-pass filter 25 and the image sensor 26 are unitized and fixed to the image sensor holder 23, and the image sensor holder 23 is fixed to the rear portion of the housing (fixed ring) 22.

  The third group lens frame 51 that holds the third lens group LG3 is supported so as to be movable in the optical axis direction with respect to the housing 22, and is driven by an AF motor 160 (FIG. 3).

  As shown in FIG. 3, a movable lens (cam ring) block 110 is movably supported inside the housing 22. As shown in FIG. 4, the movable lens (cam ring) block 110 includes a second group linear guide ring (intermediate linear guide member) 10, a cam ring (rotary ring) 11, a second feeding cylinder (linearly moving member) 12, A first feed cylinder (partially rectilinear guide member, first part rectilinear guide member) 13, cam ring coupling ring 14, and second group lens block 80 are included. Each of the second feeding cylinder 12 and the first feeding cylinder 13 constitutes an outer appearance cylinder of the two feeding steps of the zoom lens barrel ZL. As will be described later, the light of each other depends on the rotation of the cam ring 11. The amount of superimposition in the axial direction is changed.

  The cam ring 11 has a guide protrusion 11 a that is slidably fitted into a cam ring guide groove 22 a formed on the inner peripheral surface of the housing 22. As shown in FIG. 3, the cam ring guide groove 22a has a lead groove part 22a1 inclined with respect to the optical axis O and an annular groove part 22a2 centered on the optical axis O connected to the front end part of the lead groove part 22a1. doing. A zoom gear 28 (only part of which is shown in FIG. 3) meshes with a gear 11b formed at the rear end of the cam ring 11, and the zoom gear 28 is rotated by the driving force of the zoom motor 150 (FIG. 3). When the cam ring 11 is rotated by receiving the driving force of the zoom motor 150 through the zoom gear 28 and the gear 11b, the cam ring 11 extends from the retracted state of the zoom lens barrel ZL (FIG. 2) to the zoom photographing region (FIG. 1). The guide projection 11a moves in the optical axis direction while rotating under the guidance of the lead groove portion 22a1, and in the zoom photographing region (FIG. 1), the guide projection 11a is guided in the optical groove direction by receiving the guide of the annular groove portion 22a2. Rotated in place.

  The first feeding cylinder 13 and the second group linear guide ring 10 are positioned in front of and behind the cam ring 11 (combined body of the cam ring 11 and the cam ring coupling ring 14). Each of the second group linear guide ring 10 and the first feeding cylinder 13 is slidably engaged with the linear guide protrusions 10a and 13a in the optical axis direction linear guide groove 22b formed in the housing 22, It is guided so as to be movable relative to the housing 22 in the optical axis direction. The second group linear guide ring 10 has a rotation guide claw 10b that engages with a rotation guide claw 11c formed on the inner peripheral surface near the rear end of the cam ring 11, and the cam ring 11 On the other hand, relative rotation is possible, and they are coupled (bayonet coupling) so as to move together in the optical axis direction. The first feeding cylinder 13 can be rotated relative to the cam ring 11 by the sliding contact relationship between the rotation guide claw 14 a and the rotation guide claw 13 b provided on the outer peripheral surface of the cam ring coupling ring 14 coupled to the cam ring 11. Are coupled so as to move together in the optical axis direction (bayonet coupling). That is, the three members of the second group linear guide ring 10, the cam ring 11, and the first feeding cylinder 13 move together in the optical axis direction, and are linearly guided to the housing 22 in the optical axis direction. The cam ring 11 is relatively rotatable with respect to the rectilinear guide ring 10 and the first feeding cylinder 13.

  The second-group linear guide ring 10 guides the second-group lens block 80 (FIG. 4) so that it can move relatively in the optical axis direction through three linear guide bars 10c protruding forward in the optical axis direction. As shown in FIG. 8, the second group lens block 80 includes a second group lens moving frame (a partial straight guide member, a second partial straight guide) that supports the second group lens holding frame 2 that holds the second lens group LG2 therein. Member 8, and the linear guide bar 10 c is slidably engaged with the linear guide groove 8 a formed in the second group lens moving frame 8 in the optical axis direction, so that the linear guide is guided. A variable aperture stop mechanism 70 and a shutter block 100 are respectively supported by the second group lens moving frame 8 so as to be movable in the optical axis direction so as to be positioned in front of and behind the second group lens holding frame 2 (FIGS. 1 and 2). ).

  The second feeding cylinder 12 holding the first lens group LG1 has an optical axis via the first feeding cylinder 13 guided so as to be linearly movable relative to the housing 22 in the optical axis direction, and the second-group linear guide ring 10. By two members of the second group lens moving frame 8 guided so as to be linearly movable in the direction (strand), it is guided so as to be movable in the optical axis direction. As shown in FIGS. 5, 6, and 9, in the second feeding cylinder 12, there are three outer straight guide keys 12 a at the rear end and three inner guide keys 12 b inside at substantially equal intervals in the circumferential direction. It is provided one by one. An annular flange portion 12c for holding the first lens group LG1 is provided in the inner periphery of the second feeding cylinder 12, and the three inner straight guide keys 12b are respectively rearward in the optical axis direction from the annular flange portion 12c. It is formed on the outer peripheral surface of the partially cylindrical rear protruding piece 12d that protrudes toward (see FIGS. 6, 15, and 16). A tapered front end portion 12e is formed at the front end portion (rear end portion in the optical axis direction) of each inner straight guide key 12b. The tapered front end portion 12e gradually decreases in width toward the rear in the optical axis direction, that is, the front end side.

  As shown in FIGS. 7 and 10, three rectilinear guide grooves 13 c are formed on the inner peripheral surface of the first feeding cylinder 13 at substantially equal intervals in the circumferential direction. The rectilinear guide groove 13c is a long groove in the optical axis direction in which both the front and rear end portions in the optical axis direction are opened, and responds to changes in the relative position of the first feeding cylinder 13 and the second feeding cylinder 12 in the optical axis direction. Thus, the outer straight guide key 12a is slidably fitted in the optical guide direction with respect to the straight guide groove 13c, and the outer straight guide key 12a is separated rearward from the straight guide groove 13c. In the fitted state of the outer straight guide key 12a and the straight guide groove 13c, the second feeding cylinder 12 is guided by the first feeding cylinder 13 so as to be relatively movable in the optical axis direction. At the rear end in the optical axis direction of the rectilinear guide groove 13c, a tapered opening 13d is formed which gradually widens the groove width as it goes rearward in the optical axis direction. By this tapered opening 13d, the outer straight guide key 12a detached from the straight guide groove 13c can be smoothly inserted into the straight guide groove 13c.

  Further, as shown in FIGS. 8 and 11, three rectilinear guide grooves 8 b are formed on the inner peripheral surface of the second group lens moving frame 8 at substantially equal intervals in the circumferential direction. The rectilinear guide groove 8b is a long groove in the optical axis direction in which the front end in the optical axis direction is opened, and responds to changes in the relative position of the second group lens moving frame 8 and the second feeding cylinder 12 in the optical axis direction. Thus, the inner straight guide key 12b is slidably fitted to the straight guide groove 8b in the optical axis direction, and the inner straight guide key 12b is disengaged forward from the straight guide groove 8b. When the inner straight guide key 12b and the straight guide groove 8b are fitted, the second feeding cylinder 12 is guided by the second group lens moving frame 8 so as to be relatively movable in the optical axis direction. The opening at the front end in the optical axis direction of the rectilinear guide groove 8b is a tapered opening 8c that gradually increases in width as it advances forward in the optical axis direction. By the tapered opening 8c and the tapered tip 12e, the inner straight guide key 12b detached from the straight guide groove 8b can be smoothly inserted into the straight guide groove 8b.

  The second feeding cylinder 12 has a first group cam follower CF1 which is located behind the outer straight guide key 12a and protrudes in the inner diameter direction. The first group cam follower CF1 is formed on the outer peripheral surface of the cam ring 11. The group control cam groove (first cam groove) CG1 is slidably fitted. Since the second feeding cylinder 12 is guided linearly in the optical axis direction via the first feeding cylinder 13 and the second group lens moving frame 8, when the cam ring 11 rotates, the second feeding cylinder 12 follows the shape of the first group control cam groove CG1. The two-feed cylinder 12, that is, the first lens group LG1 moves along the optical axis in a predetermined locus.

  The second group cam follower CF2 provided on the outer peripheral surface of the second group lens moving frame 8 is engaged with the second group control cam groove (second cam groove) CG2 formed on the inner peripheral surface of the cam ring 11. Since the second group lens moving frame 8 is guided linearly in the optical axis direction via the second group linear guide ring 10, when the cam ring 11 rotates, the second group lens moving frame 8 follows the shape of the second group control cam groove CG2. 8, that is, the second lens group LG2 moves along a predetermined locus in the optical axis direction.

  A group biasing spring 27 made of a compression spring is inserted between the second group lens moving frame 8 and the second feeding cylinder 12, and the second group lens moving frame 8 and the second feeding cylinder 12 are separated from each other. Is being energized.

  The zoom lens barrel ZL having the above structure operates as follows. 2, the length of the optical system in the optical axis direction (distance from the object side surface of the first lens group LG1 to the imaging surface of the image sensor 26) is larger than that in the imaging state shown in FIG. It is getting shorter. In the lens barrel storage state, the second group lens moving frame 8, the second feeding cylinder 12, and the first feeding cylinder 13 have a large amount of overlapping with each other, and as shown in FIGS. 12, the inner straight guide key 12 b is fitted in the straight guide groove 8 b of the second group lens moving frame 8, while the outer straight guide key 12 a is rearwardly separated from the straight guide groove 13 c of the first feeding cylinder 13. It is in. Therefore, the second feeding cylinder 12 is guided in a straight line in the optical axis direction by the relative sliding of the inner straight guide key 12b and the straight guide groove 8b. That is, in the lens barrel storage state, the second group lens moving frame 8 guides the second feeding cylinder 12 straightly, and the first feeding cylinder 13 is not related to the rectilinear guidance of the second feeding cylinder 12.

  When a transition signal to the photographing state in the lens barrel storage state (for example, a main switch provided in a camera on which the zoom lens barrel ZL is mounted) is input, the zoom motor 150 is driven in the lens barrel feeding direction, Due to the relationship between the lead groove portion 22a1 of the cam ring guide groove 22a and the guide projection 11a, the cam ring 11 is extended forward in the optical axis direction while rotating with respect to the housing 22. The second group linear guide ring 10 and the first feeding cylinder 13 move forward together with the cam ring 11. When the cam ring 11 rotates, on the outer side, the second feeding cylinder 12 guided linearly through the second group lens moving frame 8 is moved in the optical axis direction by the relationship between the first group cam follower CF1 and the first group control cam groove CG1. It is moved along a predetermined trajectory. Specifically, at this time, the second feeding cylinder 12 is moved relative to the cam ring 11 forward in the optical axis direction. Since the cam ring 11 and the first feeding cylinder 13 are integrated in the optical axis direction, the outer rectilinear guide key 12a is guided by the first feeding cylinder 13 by the relative movement of the second feeding cylinder 12 to the front. The groove 13c is approached from the rear. Further, when the cam ring 11 is rotated, the second group lens moving frame 8 guided linearly through the second group linear guide ring 10 is moved inside by the relationship between the second group cam follower CF2 and the second group control cam groove CG2. The cam ring 11 is moved in the optical axis direction along a predetermined locus different from that of the second feeding cylinder 12. As a result, the position of the inner rectilinear guide key 12b in the rectilinear guide groove 8b changes.

When the zoom motor 150 is driven by a predetermined amount in the lens barrel feeding direction from the lens barrel retracted state, the outer rectilinear guide key 12a enters the rear end portion of the rectilinear guide groove 13c as shown in FIG. At this time, due to the shape of the tapered opening 13d, the outer rectilinear guide key 12a can surely enter the rectilinear guide groove 13c without being caught. In the state of FIG. 13, most of the inner straight guide key 12b is detached forward from the straight guide groove 8b, and the taper tip 12e is only slightly positioned near the taper opening 8c. The rectilinear guide due to the relationship between the inner rectilinear guide key 12b and the rectilinear guide groove 8b is substantially canceled. That is, the second
Switching of the rectilinear guide member in the optical axis direction with respect to the feeding cylinder 12 occurs, and the state changes from the state in which the second group lens moving frame 8 is in charge of rectilinear guidance to the state in which the first feeding cylinder 13 is in charge of rectilinear guidance. ing. The timing of switching the straight travel guide is such that after the outer straight travel guide key 12a is fitted (entered) into the straight travel guide groove 13c, the inner straight travel guide key 12b is detached from the straight travel guide groove 8b, that is, outside. Both the rectilinear guide key 12a and the inner rectilinear guide key 12b are set so as not to leave the corresponding rectilinear guide grooves 13c and 8b at the same time. Specifically, immediately before the state shown in FIG. 13 during the lens barrel feeding operation, a region D1 (FIG. 10) near the rear end of the rectilinear guide groove 13c and a region D2 (FIG. 11) near the front end of the rectilinear guide groove 8b. On the other hand, there is a state in which the corresponding linear guide keys 12a and 12b are simultaneously fitted. In other words, out of the movement range of the second feeding cylinder 12 in the optical axis direction, a part of the range in which the first feeding cylinder 13 (straight guide groove 13c) guides straight travel and the second group lens moving frame 8 (straight travel). A part of the range in which the straight guide is provided by the guide groove 8b) is overlapped with each other, and switching of the member in charge of the straight guide with respect to the second feeding cylinder 12 is performed in this overlapping portion. Thereby, when the member in charge of the straight advance guidance is switched from the second group lens moving frame 8 to the first advance cylinder 13 (or vice versa), the straight advance guide for the second advance cylinder 12 is not interrupted, and smooth operation is achieved. Can be achieved.

  When the zoom motor 150 is further driven in the lens barrel feeding direction from the state of FIG. 13, the second feeding cylinder 12 relatively moves forward with respect to the combined body of the cam ring 11 and the first feeding cylinder 13, and guides outward straight travel. The key 12a further enters the straight guide groove 13c. On the other hand, the second feeding cylinder 12 is moved forward relative to the second group lens moving frame 8, and the inner rectilinear guide key 12b is completely detached forward from the rectilinear guide groove 8b (see FIGS. 14 and 16). . Eventually, when the zoom lens barrel ZL is extended by a predetermined amount, it reaches the wide end of the zoom photographing region shown in the upper half section of FIG. When the zoom photographing area is reached, the guide projection 11a of the cam ring 11 is positioned in the annular groove 22a2 of the cam ring guide groove 22a, and the movement of the cam ring 11 in the optical axis direction is stopped.

  The first lens group LG1 and the second lens group LG2 are fed out from the lens barrel retracted state by the former moving amount of the cam ring 11 with respect to the housing 22 and the cam of the second feeding cylinder 12 with respect to the cam ring 11, respectively. The latter is determined as the sum of the amount of forward movement of the cam ring 11 relative to the housing 22 and the amount of cam extension of the second group lens moving frame 8 relative to the cam ring 11. Zooming is performed by moving the first lens group LG1 and the second lens group LG2 along the photographing optical axis O while changing the air interval between them. When the zoom motor 150 is further driven in the telephoto direction (the same direction as when extending from the lens barrel storage state to the wide end) from the wide end extended state shown in the upper half section of FIG. 1, eventually the lower half cross section of FIG. The tele end shown in FIG. In the zoom photographing region from the wide end to the tele end, the cam ring 11 is guided by the annular groove 22a2 of the cam ring guide groove 22a and rotates at a fixed position in the optical axis direction, and does not advance or retreat in the optical axis direction.

  As can be seen from the upper half section of FIG. 1 and FIG. 14, at the wide end, the outer straight guide key 12a is fitted in the straight guide groove 13c to receive the straight guide, while the inner straight guide key 12b is received from the straight guide groove 8b. It is out of the front. Further, not only at the wide end, but also at the tele end of the lower half cross section of FIG. 1, the straight guide relation by the fitting of the outer straight guide key 12a and the straight guide groove 13c is maintained. The fitting between the outer straight guide key 12a and the straight guide groove 13c is maintained in the entire zoom photographing region including the wide end and the tele end shown in FIG. In other words, in the zoom shooting area, the second feeding cylinder 12 always receives the straight guidance by the first feeding cylinder 13. As shown in the lower half cross section of FIG. 1, at the tele end, the inner rectilinear guide key 12b is fitted in the rectilinear guide groove 8b as the second lens group LG2 is moved closer to the first lens group LG1. In this state, the fitting clearance between the inner rectilinear guide key 12b and the rectilinear guide groove 8b is such that the outer rectilinear guide key 12a and the rectilinear guide groove 13c do not interfere with the rectilinear guide of the second feed cylinder 12 by the first feed cylinder 13. It is set slightly looser than the mating clearance.

  When a transition signal from the shooting state (zoom shooting area) to the storage state (for example, turning off the main switch of the camera) is input, the zoom motor 150 is driven in the lens barrel storage direction, and the zoom lens barrel ZL The storing operation opposite to the feeding operation is performed. At the wide end, as shown in FIG. 14, the outer rectilinear guide key 12a is fitted in the rectilinear guide groove 13c, and the inner rectilinear guide key 12b is disengaged from the rectilinear guide groove 8b, but in the middle of the operation in the lens barrel storing direction. (Specifically, when the movement from the position shown in FIG. 13 to the lens barrel storage direction is performed), the outer straight guide key 12a is released rearward from the straight guide groove 13c, and the inner straight guide key 12b is moved straight instead. It comes to fit in the guide groove 8b. At this time, as in the case of the lens barrel feeding operation, the second group lens is arranged such that after the inner rectilinear guide key 12b is fitted (entered) into the rectilinear guide groove 8b, the outer rectilinear guide key 12a is detached from the rectilinear guide groove 13c. A part of the range of the rectilinear guidance by the moving frame 8 and a part of the range of the rectilinear guidance by the first feeding cylinder 13 overlap each other. As a result, the second feeding cylinder 12 is switched from the state in which it is guided straight by the first feeding cylinder 13 to the state in which it is guided by the second group lens moving frame 8. When switching the straight guide, when the inner straight guide key 12b enters the straight guide groove 8b, it is caught by the relationship between the tapered tip 12e and the tapered opening 8c formed at the tip of the inner straight guide key 12b. It can enter smoothly without generating. Thereafter, until the lens barrel feeding operation is performed again, the second feeding cylinder 12 receives the rectilinear guidance by the second group lens moving frame 8, and the first feeding cylinder 13 is not involved in the rectilinear guidance of the second feeding cylinder 12.

  The third lens group frame 51 that supports the third lens group LG3 is moved back and forth in the optical axis direction by the AF motor 160 independently of the driving of the first lens group LG1 and the second lens group LG2 by the zoom motor 150 described above. Can be made. Then, when the optical system is in the zoom photographing area from the wide end to the tele end, the third lens group LG3 is moved in the optical axis direction by driving the AF motor 160 according to the subject distance information obtained by the distance measuring means. To move to and focusing is executed.

  As described above, in the zoom lens barrel ZL according to the present embodiment, the means for guiding the second feeding cylinder 12 in the optical axis direction includes two members each having a different partial linear guide range, that is, the linear guide groove 13c. This is divided into a first feed cylinder 13 and a second-group lens moving frame 8 having a rectilinear guide groove 8b, and these divided partial rectilinear guide members function in a mutually complementary manner to form one rectilinear guide mechanism. I am letting. According to this configuration, the straight guide amount in the optical axis direction (the length in the optical axis direction of each straight guide groove 13c, 8b) that each straight guide groove 13c, 8b takes charge is based on the total movement amount of the second feed cylinder 12. Therefore, the size in the optical axis direction of the first feeding cylinder 13 and the second group lens moving frame 8 can be made smaller than the movement amount of the second feeding cylinder 12. In other words, a larger amount of movement in the optical axis direction can be given to the second feeding cylinder 12 without being restricted by the size in the individual optical axis direction of the first feeding cylinder 13 and the second group lens moving frame 8. The second feeding cylinder 12 holds the first lens group LG1, and setting the movement amount in the optical axis direction to a large value is effective in increasing the zooming magnification of the zoom lens barrel ZL. Then, by reducing the size of the first feeding cylinder 13 and the second group lens moving frame 8 in the optical axis direction as compared with the movement amount of the second feeding cylinder 12, the zoom lens mirror in the lens barrel storage state shown in FIG. The storage length of the tube ZL can be shortened. That is, the amount of feeding of the second feeding cylinder 12 (first lens group LG1) can be increased while being compact in the housed state.

  As mentioned above, although demonstrated based on illustration embodiment, this invention is not limited to this embodiment. For example, in the illustrated embodiment, the cam ring 11 is drawn forward in the optical axis direction while rotating with respect to the housing 22 when changing from the lens barrel storage state to the photographing state. As a result, the amount of extension of the first lens group LG1 and the second lens group LG2 indirectly supported by the cam ring 11 with respect to the image plane (imaging element 26) can be increased. However, even if the cam ring 11 does not move in the optical axis direction and always rotates at a fixed position, the first feeding cylinder 13 (straight guide groove 13c) and the second group lens moving frame 8 (straight guide groove). The above-mentioned effect is obtained that the movement amount in the optical axis direction of the second feeding cylinder 12 can be set larger than the individual optical axis size in 8b). Therefore, the present invention is also effective for a lens barrel of a type in which the rotating ring corresponding to the cam ring 11 does not move in the optical axis direction.

  In the illustrated embodiment, the second advance cylinder 12 is guided straight by the two members of the first extension cylinder 13 and the second group lens moving frame 8, but three or more portions are provided for one rectilinear movement member. It is also possible to perform a straight-ahead guide by a straight-ahead guide member.

8 2 group lens moving frame (partial linear guide member, second partial linear guide member)
8a rectilinear guide groove 8b rectilinear guide groove 8c taper opening 10 rectilinear guide ring for second group (intermediate rectilinear guide member)
10a rectilinear guide protrusion 10c rectilinear guide bar 11 cam ring (rotating ring)
12 Second delivery cylinder (straight forward moving member)
12a Outer rectilinear guide key 12b Inner rectilinear guide key 12d Backward projecting piece 12e Taper tip 13 First delivery cylinder (partial rectilinear guide member, first part rectilinear guide member)
13a rectilinear guide protrusion 13c rectilinear guide groove 13d taper opening 14 cam ring coupling ring 22 housing (fixed ring)
22b Straight guide groove 80 2nd lens block 110 Movable lens (cam ring) block 150 Zoom motor 160 AF motor CF1 1st cam follower CF2 2nd cam follower CG1 1st control cam groove (first cam groove)
CG2 2 group control cam groove (second cam groove)
LG1 First lens group (optical element)
LG2 Second lens group (another optical element)
LG3 Third lens group O Optical axis ZL Zoom lens barrel

Claims (11)

In a lens barrel that linearly moves a linearly moving member that holds an optical element in the direction of the optical axis by rotating a rotary ring,
A plurality of partial rectilinear guide members that divide into a plurality of different moving ranges and perform rectilinear guidance in the optical axis direction with respect to the one rectilinear moving member
The moving ranges of the linear guides with respect to the one linearly moving member by the plurality of partial linearly guiding members have portions that overlap each other, and in the overlapping portion, between the plurality of partial linearly guided members with respect to the one linearly moving member. A linear guide mechanism for a lens barrel, wherein the guide guide is switched. In the linear guide mechanism of the lens barrel according to claim 1,
The plurality of partial rectilinear guide members include a first partial rectilinear guide member that guides the one rectilinearly moving member in the optical axis direction when the lens barrel is in a photographing state, and the lens barrel does not perform photographing. A second partial rectilinear guide member that linearly guides the one rectilinear moving member in the optical axis direction when in the retracted state;
During the transition from the retracted state of the lens barrel to the photographing state, the rectilinear guidance by the second partial rectilinear guide member for the one rectilinear moving member is released, and the first partial rectilinear guide member starts rectilinear guidance. A linear guide mechanism for a lens barrel. 3. The linear guide mechanism for a lens barrel according to claim 2, wherein the linear guide by the second partial guide member is released with respect to the one linearly moving member when the lens barrel shifts from the housed state to the photographing state. A lens barrel rectilinear guide mechanism characterized in that the timing at which the linear guide by the first partial rectilinear guide member is started is earlier than the timing at which the first partial rectilinear guide member is started. 4. The linear movement guide mechanism for a lens barrel according to claim 2, wherein the optical element constitutes a part of a zoom optical system, and the first partial linear movement guide member extends from the wide end to the tele end of the zoom optical system. A linear movement guide mechanism for a lens barrel, wherein the linear movement member is linearly guided in the direction of the optical axis within a movement range of the entire zoom photographing area. 5. The linear guide mechanism for a lens barrel according to claim 2, wherein the rotating ring includes a first cam groove engaged with a cam follower provided on the one linearly moving member, and the first cam groove. A cam ring having a second cam groove of a different locus from the cam groove of
The first partial rectilinear guide member is coupled to the cam ring so that relative movement in the optical axis direction is restricted and is relatively rotatable,
The second partial rectilinear guide member has a cam follower that holds an optical element different from the optical element held by the one rectilinear movement member and engages with the second cam groove of the cam ring, A linear guide mechanism for a lens barrel, which is linearly moved in the optical axis direction along a locus different from that of the one linearly moving member in accordance with the rotation of the cam ring. 6. The linear guide mechanism for a lens barrel according to claim 5, wherein the cam ring moves forward in the optical axis direction while rotating with respect to the fixed ring when the lens barrel changes from the housed state to the photographing state.
The lens barrel rectilinear guide mechanism, wherein the first partial rectilinear guide member is linearly guided in the optical axis direction by a rectilinear guide portion provided on the fixed ring. 7. The linear movement guide mechanism for a lens barrel according to claim 5, wherein the second partial linear movement guide member is interposed via an intermediate linear movement guide member that receives the linear movement guide in the optical axis direction by the linear movement guide portion provided on the fixed ring. A linear guide mechanism for a lens barrel, characterized by being guided straight in the direction of the optical axis. 8. The linear movement guide mechanism for a lens barrel according to claim 5, wherein the first linear movement member and the first partial linear movement guide member overlap each other according to the rotation of the cam ring. A lens barrel linear guide mechanism characterized by being an appearance ring of a lens barrel that changes the lens. 9. The linear guide mechanism for a lens barrel according to claim 1, wherein each of the plurality of partial straight guide members has a straight guide groove that is open at least at one end in the optical axis direction and extends in the optical axis direction. Have
The one linear movement member has a plurality of kinds of linear guide keys inserted into and removed from the respective linear guide grooves of the plurality of partial linear guide members through the opening end portion, and the linear guide of the lens barrel mechanism. 10. The linear guide mechanism for a lens barrel according to claim 9, wherein the opening end of the straight guide groove is a tapered opening that gradually increases the groove width. 10. The linear guide mechanism for a lens barrel according to claim 9, wherein the linear guide key is formed with a tapered tip at the insertion end into the straight guide groove so that the taper gradually decreases in width toward the tip. A lens barrel straight-ahead guide mechanism.

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