JP6737095B2 - Lens barrel - Google Patents

Description

The present invention relates to a lens barrel capable of displacing a lens in an optical axis direction.

In a lens barrel mounted on a digital still camera or the like capable of zoom photography, a cam follower provided on a moving frame holding a zoom lens is engaged with a cam groove formed on the cam barrel to separate the moving frame and the cam barrel. By relatively rotating the zoom lens, the displacement of the zoom lens in the optical axis direction can be accurately performed.

By the way, for example, when a user carelessly touches a digital still camera or the like mounted on the edge of a table, it may be dropped on the floor or the like. In this case, when the cam follower is pressed against the side surface of the cam groove and plastically deforms due to a strong load caused by the inertia of the moving frame when receiving a shock at the time of drop, fluctuations in the distance between the lenses exceeding the allowable value or It may cause eccentricity of the lens. In particular, due to the demand for higher zoom ratio and larger image pickup device, the lens barrel itself tends to be larger in recent years, and the weight of the lens barrel and the moving frame itself tends to increase. The impact of is likely to increase.

On the other hand, in Patent Document 1, it is possible to disperse and support the impact force by engaging three cam followers made of metal and three cam followers made of resin in the cam groove. A lens barrel having improved impact resistance is disclosed.

JP, 2009-258295, A

By the way, a cam cylinder having a cam groove formed on its peripheral surface is generally made of resin in consideration of cost and weight reduction. Also in the lens barrel of Patent Document 1, the frame member, which is the cam barrel, is made of resin and is integrated with the resin pin. If the cam barrel is made of resin, the shapes of the actually molded cam grooves may differ from each other due to manufacturing errors, even if the cam grooves are designed to have the same shape. It is highly likely. When 6 cam followers are simultaneously engaged with the cam grooves having different shapes, a plurality of cam followers compete through the cam grooves when the moving frame and the cam barrel are relatively rotated. May occur, which may impede smooth zoom movement.

On the other hand, although there is no specific description in Patent Document 1, a gap may be provided between the three cam followers made of resin and the cam grooves. With such a configuration, since the shapes and the like of the three metal cam followers can be adjusted individually, even if the shapes of the cam grooves are different, they can be engaged with each other without competing with each other, thereby smoothing the operation. Zoom movement can be secured. On the other hand, the three resin cam followers do not interfere with the zoom movement by not normally contacting the cam groove, and when impact force is applied, they can contact each other to receive a load, This can improve impact resistance.

However, it has been found that when a digital still camera or the like having such a lens barrel is dropped, a certain problem occurs. This problem will be specifically described. In the lens barrel having the above-described configuration, the three metal cam followers first receive the reaction force F1 from the cam groove due to the impact force at the time of dropping, and after the elastic deformation occurs in each part, the three The impact force is absorbed in two steps such that the resin cam follower contacts the cam groove and receives the reaction force F2. As long as this total reaction force (F1 + F2) is within the allowable range, it has little effect, but if the impact force is excessive such as dropping from a high position, the deformation of the metal cam follower attachment part that receives the impact force first, There is a risk of exceeding the elastic region and reaching the plastic region. If the metal cam follower mounting part is plastically deformed, the contact position between the cam follower and the cam groove may change, which may cause fluctuations in the distance between the lenses that exceed the allowable value and decentering of the lens. .. On the other hand, if it is attempted to increase the rigidity of the mounting portion of the cam follower in order to withstand the impact force, it is not preferable because the lens barrel is further increased in size. Such a problem is likely to be a particular problem when a digital still camera or the like is accidentally dropped with the lens barrel retracted into the camera body.

The present invention is intended to solve the above problems, and an object of the present invention is to provide a lens barrel that can be accurately downsized while ensuring compactness and impact resistance. ..

Lenses lens barrel of the present invention is the lens barrel for holding the displacement in the lens in the optical axis direction,
A tubular member having a main engagement groove and a sub engagement groove on the circumferential surface,
A frame member that includes a main engagement piece that engages with the main engagement groove, and a sub engagement piece that is disposed in the sub engagement groove.
The lens is held on at least one of the tubular member and the frame member,
When the tubular member and the frame member are relatively rotated, the main engaging piece relatively moves along the main engaging groove, and the sub engaging along the sub engaging groove. The pieces move relative to each other,
At the time of shooting, the sub-engaging piece is not in contact with the sub-engaging groove, the main engaging piece is in contact with the main engaging groove, thereby performing positioning of the lens in the optical axis direction,
The main engagement piece is in contact with the main engagement groove and the sub-engagement piece is in contact with the sub-engagement groove during non-shooting.
Another lens barrel of the present invention is a lens barrel that holds a lens displaceably in the optical axis direction,
A tubular member having a main engagement groove and a sub engagement groove on the circumferential surface,
A frame member that includes a main engagement piece that engages with the main engagement groove, and a sub engagement piece that is disposed in the sub engagement groove.
The lens is held on at least one of the tubular member and the frame member,
When the tubular member and the frame member are relatively rotated, the main engaging piece relatively moves along the main engaging groove, and the sub engaging along the sub engaging groove. The pieces move relative to each other,
At the time of shooting, the main engagement piece is in contact with the main engagement groove to perform positioning of the lens in the optical axis direction,
The main engagement piece is in contact with the main engagement groove at the time of non-imaging, and the sub engagement piece is in contact with the sub engagement groove,
The sub-engagement groove connects the 21st area in which the sub-engagement piece is located during shooting, the 22nd area in which the sub-engagement piece is located during non-shooting, and the 21st area and the 22nd area. If the minimum gap between the 21st region and the sub-engaging piece is C and the minimum gap between the 23rd region and the sub-engaging piece is D, then C>D. It holds.

According to the present invention, it is possible to provide a lens barrel that can be accurately downsized while ensuring downsizing and impact resistance.

It is an external view of a digital still camera which is an example of an image pickup apparatus including the lens barrel according to the present embodiment. 3 is a perspective view of the lens barrel 100 according to the present embodiment attached to the digital still camera 1. FIG. FIG. 3 is a front view of the lens barrel 100 as viewed from the object side in the optical axis direction. It is the figure which saw the lens barrel 100 of FIG. 3 by the IV-IV line, and was seen in the arrow direction. 6 is a perspective view of a third holding frame 115 and a shutter mechanism 119. FIG. FIG. 3 is a perspective view showing a straight barrel 120 and a rotary barrel 130 removed from the lens barrel 100. It is the front view which looked at the structure of FIG. 6 from the object side in the optical axis direction. It is the side view which looked at the structure of FIG. 6 from the optical axis orthogonal direction. FIG. 9 is a sectional view of the configuration of FIG. 7 taken along line IX-IX and viewed in the direction of the arrow. FIG. 9 is a cross-sectional view of the configuration of FIG. 8 taken along line XX and viewed in the direction of the arrow. FIG. 11 is an enlarged view of a portion indicated by an arrow XI in the configuration of FIG. 10, which is a state of a photographing region. FIG. 11 is an enlarged view of a portion indicated by an arrow XII in the configuration of FIG. 10, showing a state of a photographing region. FIG. 6 is a development view of an outer peripheral surface of a rotary cylinder 130. It is a figure which expands and shows the site|part shown by the arrow XIV of FIG. 13 in the cam groove 131. It is a figure which expands and shows the site|part shown by the arrow XV of FIG. 13 in the cam groove 132. As shown in FIG. FIG. 12 is a sectional view similar to FIG. 11, but in a state of a non-imaging region. FIG. 13 is a sectional view similar to FIG. 12, but showing a state of a non-imaging region. FIG. 4 is a development view of an inner peripheral surface of a rotary cylinder 130. FIG. 15 is a view similar to FIG. 14 of a cam groove 131 ′ according to another embodiment. FIG. 8 is a development view similar to FIG. 6 of a helicoid cylinder 230 according to another embodiment.

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an external view of a digital still camera which is an example of an image pickup apparatus including the lens barrel according to the present embodiment. FIG. 1A is a front view of the digital still camera 1, and FIG. 1B is a rear view.

As shown in FIG. 1, the digital still camera 1 is composed of an image pickup section 2 having a lens barrel and an image pickup element, and a camera body section 3.

The image pickup unit 2 includes a lens barrel capable of zooming and a solid-state image pickup device such as a CCD, and a subject image formed via the lens barrel can be converted into an image signal by the solid-state image pickup device.

The camera body 3 includes an LCD display unit 6 including an LCD (Liquid Crystal Display), an EVF (Electronic View Finder) 7, and an external connection terminal for connecting the digital still camera 1 to a personal computer (not shown). The image signal captured by the image pickup unit 2 is subjected to predetermined signal processing to display an image on the LCD display unit 6 or the EVF 7, record an image on a recording medium such as a memory card (not shown), or use a personal computer. Processing such as image transfer to a computer can be performed.

On the front surface of the camera body portion 3, a flash light emitting portion 4 is provided at an appropriate place on the upper portion. Further, on the rear surface of the camera body 3, an LCD display unit 6 and an EVF 7 are provided for displaying captured images and reproducing and displaying recorded images.

On the upper surface of the camera body 3, there are provided a shutter button 5 and a shooting mode selector switch (not shown) for switching between the “recording mode” and the “playback mode” near the shutter button 5. The recording mode is a mode in which a photograph is taken from the photographing standby state through the exposure control process to the photographing, and the reproduction mode is a mode in which the photographed image recorded in the memory card is reproduced and displayed on the LCD display unit 6 or the EVF 7. is there.

On the back surface of the camera body 3, there is provided a playback frame advance switch/zoom switch 9 for frame-by-frame advancement of reproduced images and zoom operation during shooting. The frame advance of the reproduced image by the reproduction frame advance switch/zoom switch 9 means that the camera is set in the reproduction mode and the images recorded in the memory card are sequentially displayed on the LCD display unit 6 together with the frame number. It should be noted that it is also possible to instruct to change the image display on the LCD display unit 6 in the ascending order direction (shooting order direction) or the descending order direction (direction opposite to the shooting order). In the zoom operation at the time of shooting, by operating the reproduction frame advance switch/zoom switch 9, the image pickup optical system, which is a zoom lens, can be zoomed in the tele direction or in the wide direction.

Further, on the back surface of the camera body 3, an EVF changeover switch 8 for selecting the LCD display 6 for displaying an image and the EVF 7 is provided.

A battery (not shown) as a power source for operating the digital still camera 1 is provided inside the bottom surface of the camera body 3.

FIG. 2 is a perspective view of the lens barrel 100 according to the present embodiment attached to the digital still camera 1, and FIG. 3 is a front view of the lens barrel 100 seen from the object side in the optical axis direction. 4 is a view of the lens barrel 100 of FIG. 3 taken along line IV-IV and viewed in the direction of the arrow.

The lens barrel 100 according to the present embodiment will be described by taking a zoom lens having a five-group configuration as an example. The lens barrel 100 has an optical system including a first lens group L1, a second lens group L2, a third lens group L3, a fourth lens group L4, and a fifth lens group L5 in order from the object side. The first lens group L1, the second lens group L2, the third lens group L3, and the fourth lens group L4 move (displace) in the optical axis direction while changing the distance between the groups to perform zooming. The fourth lens unit L4 also independently moves in the optical axis direction to perform focusing. The fifth lens group L5 is a lens group that does not move in the optical axis direction during imaging.

A schematic configuration of the lens barrel 100 will be described with reference to FIG. The lens barrel 100 is provided with an outer fixed barrel 110, a rectilinear barrel (frame member) 120, a rotary barrel (tubular member) 130, and an inner fixed barrel 140 coaxially from the outside in the direction orthogonal to the optical axis, all of which are made of resin. It is made. The outer fixed cylinder 110 whose end is fixed to the camera body 3 has a pair of guide grooves 111 extending in the optical axis direction on its inner side surface. A protrusion 121 that engages with the guide groove 111 is provided on the outer periphery of the straight-moving barrel 120, which allows the straight-moving barrel 120 to move in the optical axis direction with respect to the outer fixed barrel 110 without rotating. There is. A first holding frame 112 that holds the first lens unit L1 is attached to the inner periphery of the object-side end (the left end in FIG. 4) of the rectilinear barrel 120.

As will be described later in detail, a metal pin (main engagement piece) 150 and a resin pin (sub-engagement piece) 160 are provided on the inner circumference of the rectilinear barrel 120. A cam groove (main engagement groove) 131 for accommodating the pin 150 is formed on the outer periphery of the rotary cylinder 130 held so as to be rotatable only about the optical axis, and a cam groove (accommodating sub-engagement) for accommodating the pin 160 is formed. A groove) 132 is formed. The second holding frame 113 that holds the second lens group L2 is fixed to the ends of two guide shafts 114 (only one is shown in FIG. 4) extending in the optical axis direction. The guide shaft 114 is engaged with a hole (not shown) in the inner fixed barrel 140, and is slidable in the hole so as to be movable in the optical axis direction together with the second holding frame 113. The third lens group L3 provided in the inner fixed barrel 140 is held by a third holding frame (frame member) 115.

In the inner fixed barrel 140, the fourth lens group L4 is held by a fourth holding frame 117, and the fourth holding frame 117 is fixed to the inner fixed barrel 140 and has two guides extending in the optical axis direction. It is movable along the axis 116 in the optical axis direction. The fifth lens group L5 is fixed to the end of the outer fixed barrel 110 by the fifth holding frame 118. A shutter mechanism 119 is arranged on the object side of the third lens unit L3.

FIG. 5 is a perspective view of the third holding frame 115 and the shutter mechanism 119. As shown in the figure, the third holding frame 115 is held by two guide shafts 116. Further, an arm portion 115a is integrally formed so as to extend in the optical axis direction from the outer periphery of the third holding frame 115, and a metal pin 170 and a resin pin 180 are further formed from the arm portion 115a. , Are fixedly arranged so as to project radially outward. As shown by a dotted line in FIG. 9 described later, the pin 170, which is a main engagement piece, is housed in a cam groove (main engagement groove) 133 formed on the inner circumference of the rotary cylinder 130, and the auxiliary engagement is performed. The pin 180, which is one piece, is housed in a cam groove (sub-engagement groove) 134 formed on the inner circumference of the rotary cylinder 130.

FIG. 6 is a perspective view showing the lens barrel 100 with the rectilinear barrel 120 and the rotary barrel 130 removed, and FIG. 7 is a front view of the configuration of FIG. 6 seen from the object side in the optical axis direction. 6 is a side view of the configuration of FIG. 6 viewed from the direction orthogonal to the optical axis, FIG. 9 is a cross-sectional view of the configuration of FIG. 7 taken along the line IX-IX and viewed in the direction of the arrow, and FIG. FIG. 9 is a cross-sectional view of the configuration of FIG. 8 taken along line XX and viewed in the direction of the arrow. 11 and 12 are enlarged views of the portions indicated by arrows XI and XII in the configuration of FIG.

As shown in FIGS. 6 and 10, projections 121 that are raised in a substantially rectangular shape are formed at 60-degree intervals on the outer periphery of the image-side end of the straight-moving barrel 120. A stepped hole 122 is formed in the upper projection 121 in FIG. 10 and in the projection 121 arranged 120° away from the upper projection 121.

As shown in FIG. 11, the stepped hole 122 has an enlarged diameter hole portion 122a and a reduced diameter hole portion 122b. Further, the metal pin 150 has a shape in which a cylindrical portion 150a, a disc portion 150b, and a truncated cone portion 150c are coaxially connected. The pin 150 is attached to the stepped hole 122 by inserting the cylindrical portion 150a into the reduced diameter hole portion 122b and abutting the disk portion 150b against the enlarged diameter hole portion 122a.

On the other hand, the inner peripheral sides of the three protrusions 121 in which the stepped holes are not formed in the straight advancing cylinder 120 are raised in a truncated cone shape as shown in FIG. 12, and this constitutes a resin pin 160. The pin 160 has a flat top surface 160a and a conical surface 160b connecting to the top surface 160a.

The pin 150 is housed and arranged in a cam groove 131 formed on the outer circumference of the rotary cylinder 130, and the pin 160 is housed and arranged in a cam groove 132 formed on the outer circumference of the rotary cylinder 130. The cam grooves 131 and 132 are formed at equal intervals in the circumferential direction. The cam grooves 131 and 132 have the same shape in design, and are tapered so that both side surfaces approach each other toward the bottom in the cross sections of FIGS. More specifically, the cam groove 131 has a bottom surface 131a and a pair of side surfaces 131b connected to the bottom surface 131a. The cam groove 132 also has a bottom surface 132a and a pair of side surfaces 132b connected to the bottom surface 132a.

FIG. 13 is a development view of the outer peripheral surface of the rotary cylinder 130. 14 is an enlarged view of a portion of the cam groove 131 indicated by an arrow XIV in FIG. 13, and FIG. 15 is an enlarged view of a portion of the cam groove 132 indicated by an arrow XV in FIG. The groove width is exaggerated for ease of understanding, and the outlines of the main parts of the pins 150 and 160 viewed in the same direction are schematically shown by dotted lines.

In FIG. 14, the cam groove 131 has a photographing area (eleventh area) 131A in which the pin 150 is located at the time of photographing, and a non-photographing area 131B in which the pin 150 is located at times other than during photographing (referred to as non-photographing time). .. The non-imaging area 131B has a transition area (thirteenth area) 131C which is connected to the imaging area 131A and whose groove width gradually increases as the distance from the imaging area 131A increases. The non-imaging area 131B other than the transition area 131C is the twelfth area.

In the photographing area 131A, as shown in FIG. 11, the pin 150 relatively slides while being in contact with the side surface 131b of the cam groove 131. By moving the pin 150 in the shooting area 131A away from the non-shooting area 131B, the straight lens barrel 120 is driven so that the zoom lens approaches the tele end side, or moves toward the non-shooting area 131B. As a result, the rectilinear barrel 120 is driven so that the zoom lens is on the wide end side, and thereby the zoom lens can be accurately positioned in the optical axis direction. On the other hand, in the non-photographing area 131B, as shown in FIG. 16, the pin 150 is not in contact with the side surface 131b of the cam groove 131.

Here, when the minimum gap between the truncated conical portion 150c of the pin 150 and the side surface 131b of the cam groove 131 is Δ1, the minimum gap Δ1 in the non-imaging region 131B other than the transition region 131C is A, and in the transition region 131C. Assuming that the minimum gap Δ1 is B, B increases as the pin 150 moves away from the imaging region 131A, but A>B is always satisfied. The minimum gap Δ1 (=B) in the transition area 131C increases as the pin 150 is displaced from the photographing area 131A side to the non-photographing area 131B side. By providing the transition area 131C by gradually changing the minimum gap Δ1 in this manner, it is possible to suppress a sudden change in the driving sound when the pin 150 moves between the shooting area 131A and the non-shooting area 131B. ..

In FIG. 15, the cam groove 132 has a photographing region (21st region) 132A in which the pin 160 is located at the time of photographing, and a non-imaging region 132B in which the pin 160 is located at a time other than during photographing (referred to as non-photographing time). .. The non-imaging region 132B has a transition region (23rd region) 132C which is connected to the photographing region 132A and whose groove width gradually increases as the distance from the photographing region 132A increases. The non-imaging area 132B other than the transition area 132C is the 22nd area.

In the non-imaging area 132B, as shown in FIG. 17, the pin 160 relatively slides while being in contact with the side surface 131b of the cam groove 131. Therefore, by moving the pin 160 in the non-photographing region 132B to the side away from the photographing region 132A to drive the rectilinear barrel 120, the lens barrel is retracted. On the other hand, in the photographing area 132A, as shown in FIG. 12, the pin 160 is not in contact with the side surface 132b of the cam groove 132.

Here, when the minimum clearance between the conical surface 160b of the pin 160 and the side surface 132b of the cam groove 132 is Δ2, and the minimum clearance Δ2 in the imaging area 132A is C, and the minimum clearance Δ2 in the transition area 132C is D, Although D decreases as the pin 160 moves away from the shooting area 132A, C>D is always satisfied. The minimum gap Δ2 (=D) in the transition area 132C decreases as the pin 160 is displaced from the shooting area 132A side to the non-shooting area 132B side. By providing the transition area 132C by gradually changing the minimum gap Δ2 in this manner, it is possible to suppress a sudden change in the driving sound when the pin 160 moves between the shooting area 132A and the non-shooting area 132B. ..

FIG. 18 is a development view of the inner peripheral surface of the rotary cylinder 130. In the figure, on the inner peripheral surface of the rotary cylinder 130, a cam groove 133 facing the pin 170 (see FIGS. 6 and 9), a cam groove 134 facing the pin 180 (see FIGS. 6 and 9), and a cam groove 133. Also, a common introduction path 135 that connects each end of the cam groove 134 and the peripheral edge of the rotary cylinder 130 is formed. At the time of assembly, the rotary cylinder 130 and the third holding frame 115 (FIG. 6) are relatively moved in the optical axis direction so that the pins 170 and 180 enter through the common introduction path 135, and then the rotary cylinder 130 and the By rotating the 3 holding frame 115 relative to each other, the pin 170 can be arranged in the cam groove 133 and the pin 180 can be arranged in the cam groove 134.

The cam groove 133 has a photographing region (eleventh region) 133A in which the pin 170 is located during photographing, and a non-photographing region 133B in which the pin 170 is located except during photographing (referred to as non-photographing). The non-imaging area 133B has a transition area (thirteenth area) 133C which is connected to the imaging area 133A and whose groove width gradually increases as the distance from the imaging area 133A increases. The non-imaging area 133B other than the transition area 133C is the twelfth area.

In the photographing area 133A, the pin 170 relatively slides while being in contact with the side surface of the cam groove 133. Therefore, the pin 170 drives the third holding frame 115 so that the zoom lens approaches the telephoto end side by moving the pin 170 away from the non-shooting area 133B in the shooting area 133A, or approaches the non-shooting area 131B. By moving the zoom lens to the side, the third holding frame 115 is driven so that the zoom lens moves to the wide end side, and thereby the zoom lens can be accurately positioned in the optical axis direction. On the other hand, in the non-photographing area 133B, the pin 170 is not in contact with the cam groove 131.

Here, although not shown, when the minimum clearance between the pin 170 and the cam groove 133 is Δ1, the minimum clearance Δ1 in the non-imaging area 133B other than the transition area 133C is A, and the minimum clearance Δ1 in the transition area 133C is If B is set, B increases as the pin 170 moves away from the photographing area 133A, but A>B is always satisfied. The minimum gap Δ1 (=B) in the transition area 133C increases as the pin 170 is displaced from the photographing area 133A side to the non-photographing area 133B side. By providing the transition area 133C by gradually changing the minimum gap Δ1 in this manner, it is possible to suppress a sudden change in the driving sound when the pin 170 moves between the shooting area 133A and the non-shooting area 133B. ..

Further, in FIG. 18, the cam groove 134 has a photographing region (21st region) 134A in which the pin 180 is located at the time of photographing (meaning that the lens group is at a photographing position), and at a time other than photographing (non-photographing). (Time: means that there is a lens group in a position where shooting is not possible) and a non-shooting area 134B in which the pin 180 is located. The non-imaging area 134B has a transition area (23rd area) 134C which is connected to the imaging area 134A and whose groove width gradually increases as the distance from the imaging area 134A increases. The non-imaging area 134B other than the transition area 134C is the 22nd area.

In the non-imaging area 134B, the pin 180 relatively slides while being in contact with the side surface of the cam groove 134. Therefore, by moving the third holding frame 115 by moving the pin 180 in the non-photographing region 134B to the side away from the photographing region 134A, the lens barrel is retracted. On the other hand, in the photographing area 134A, the pin 180 is not in contact with the cam groove 134.

Here, although not shown, when the minimum gap Δ2 in the photographing region 134A is C and the minimum gap Δ2 in the transition region 134C is D when the minimum gap between the pin 180 and the cam groove 134 is Δ2, D is Although the pin 180 decreases as the pin 180 moves away from the photographing area 134A, C>D is always satisfied. The minimum gap Δ2 in the transition area 134C decreases as the pin 180 is displaced from the photographing area 134A side to the non-photographing area 134B side. By providing the transition region 134C so that the minimum gap Δ2 (=D) is gradually changed in this way, a rapid change in the driving sound when the pin 180 moves between the photographing region 134A and the non-photographing region 134B. Etc. can be suppressed. The pins 170 and 180 and the cam grooves 133 and 134 have the same configurations as those of the pins 150 and 160 and the cam grooves 131 and 132 except those described above.

The operation of the lens barrel 100 will be described. During the zoom operation, the motor MT shown in FIG. 2 rotates so that the rotary cylinder 130 rotates via a power transmission mechanism (not shown). Then, the cam groove 131 of the rotary cylinder 130 is rotationally moved, so that the pin 150 receives a driving force in the optical axis direction and the rotational direction, but the straight-moving cylinder 120 can only go straight by the projection 121 engaging with the guide groove 111. Therefore, it is moved in the optical axis direction according to the rotation of the rotary cylinder 130. As a result, the first lens unit L1 is displaced to a predetermined position in the optical axis direction.

Furthermore, the second holding frame 113 has pins (not shown) that engage with cam grooves (not shown) provided on the inner periphery of the rotary cylinder 130, and accordingly, depending on the rotation of the rotary cylinder 130. The guide shaft 114 moves in the optical axis direction along a hole (not shown) in which the guide shaft 114 slides. As a result, the second lens unit L2 is displaced to a predetermined position in the optical axis direction.

Further, since the third holding frame 115 receives a driving force from the cam groove 132 provided on the inner circumference of the rotary cylinder 130 via the pin 170, the third lens group L3 is guided by the guide shaft 116, Displace to a predetermined position in the direction.

The fourth holding frame 117 is configured to be displaced in the optical axis direction via a motor and a power transmission mechanism (not shown). The motor MT for rotating the rotary cylinder 130 and the motor for driving the fourth holding frame 117 are interlocked with each other in response to a signal from the digital still camera 1 during the zoom operation, and therefore the first lens group L1 to the fourth lens group L4. Can be respectively displaced to positions suitable for zooming. The fifth lens unit L5 does not move. Further, since the motor for driving the fourth holding frame 117 is independently driven according to the signal from the digital still camera 1, only the fourth lens unit L4 can be displaced in the optical axis direction during focusing.

On the other hand, when the power switch (not shown) is turned off, the pin 160 engages with the non-photographing region 132B of the cam groove 132, the straight-moving barrel 120 is driven to the image side, and the second holding frame 113 is also moved to the image side. The pin 180 is engaged with the non-photographing region 134B of the cam groove 134 to drive the third holding frame 115 toward the image side, and the fourth holding frame 117 is also moved in the same direction to move the lens mirror. The cylinder 100 is in the collapsed state shown in FIG.

According to the present embodiment described above, the pin 150 contacts the cam groove 131 and the pin 170 contacts the cam groove 133 during shooting, so that the zoom lens can be accurately positioned in the optical axis direction. .. Further, since the pin 160 is not in contact with the cam groove 132 and the pin 180 is not in contact with the cam groove 134 at the time of photographing, even if the shapes of the cam grooves 132 and 134 are different due to manufacturing errors or the like, it is necessary. Bidding through the cam groove can be suppressed.

On the other hand, at the time of non-shooting, the pin 160 is in contact with the cam groove 132 and the pin 180 is in contact with the cam groove 134, but the pin 150 is not in contact with the cam groove 131 and the pin 170 is in contact with the cam groove 133. Therefore, if the digital still camera 1 is accidentally dropped, the impact force is first absorbed by the pin 160 and the cam groove 132, and the pin 180 and the cam groove 134 which are in contact with each other. As a result, the contact between the pin 150 and the cam groove 131 or the contact between the pin 170 and the cam groove 133 is suppressed, and high-precision zoom lens drive can be ensured even after dropping. Further, when the impact force is excessive, there is a possibility that the pin 150 and the cam groove 131 may come into contact with each other, or the pin 170 and the cam groove 133 may come into contact with each other. Since the pin 160 and the cam groove 132, and the pin 180 and the cam groove 134 absorb much of the impact force, the plastic deformation of the pins 150 and 170 can be effectively avoided to ensure a highly accurate zoom lens drive. it can. Incidentally, since the resin pin 160 is in contact with the cam groove 132 and the resin pin 180 is in contact with the cam groove 134 at the time of non-shooting, it is expected that the positioning accuracy of each lens will be lowered to some extent. Therefore, there is no particular problem.

FIG. 19 is a view similar to FIG. 14 of a cam groove 131 ′ according to another embodiment. In the present embodiment, the cam groove 131' has a shooting area 131A in which the pin 150 is located during shooting and a non-shooting area 131B in which the pin 150 is located during non-shooting. However, as shown in the drawing, the cross-sectional shapes of the cam grooves 131' in the photographing area 131A and the non-photographing area 131B are the same. Therefore, in the present embodiment, the pin 150 comes into contact with the cam groove 131' throughout the shooting and non-shooting. The other configuration is the same as that of the above-described embodiment.

Unlike the above-described embodiment, in the present embodiment, the pin 160 contacts the cam groove 132, the pin 180 contacts the cam groove 134, and the pin 150 contacts the cam groove 131 during non-shooting. Further, since the pins 170 are in contact with the cam grooves 133, that is, the six pins are in contact with the six cam grooves. Therefore, when the digital still camera 1 is accidentally dropped, the impact force is dispersed and absorbed by the 6 pairs of pins and the cam grooves, so that it is possible to ensure a highly accurate zoom lens drive even after the drop. .. Other effects are similar to those of the above-described embodiment.

20 is a development view of a helicoid cylinder 230 according to another embodiment, similar to FIG. In the helicoid cylinder (cylindrical member) 230 of this modification, three helicoid grooves (main engagement grooves) HG and three sub engagement grooves DG are formed at equal intervals instead of the cam grooves. Metallic helicoids (main engaging pieces) HC protruding from a frame member (not shown) are respectively arranged in the helicoid grooves HG, and protruded from a frame member holding a lens (not shown) in the sub engaging groove DG. The sub-helicoids (sub-engagement pieces) DH made of resin are arranged.

The helicoid groove HG has a photographing region (11th region) HGA where the helicoid HC is located at the time of photographing, a non-photographing region HGB where the helicoid HC is located at a time other than photographing (referred to as non-photographing time), and an introduction path HGC. Have. Each helicoid HC is arranged in the non-imaging region HGB through the introduction path HGC from the outside of the helicoid cylinder 230. The non-shooting area HGB may be provided with a transition area which is connected to the shooting area HGA and whose groove width gradually increases as the distance from the shooting area HGA increases. In this case, the transition area becomes the 13th area, and the non-imaging area HGB other than this transition area becomes the 12th area. The relationship of the minimum gap Δ1 between the helicoid HC and the helicoid groove HG in this case is the same as that of the above-described embodiment.

In the photographing area HGA, the helicoid HC relatively slides while being in contact with the helicoid groove HG. Therefore, the helicoid HC moves toward the side away from the non-shooting area HGB in the shooting area HGA to move the zoom lens toward the tele end side, or moves toward the non-shooting area HGB to move the zoom lens wide. By approaching the end side, it is possible to accurately position the zoom lens in the optical axis direction. On the other hand, in the non-imaging region HGB, the helicoid HC is not in contact with the helicoid groove HG. Therefore, when the digital still camera is accidentally dropped in such a state, the collision between the helicoid HC and the helicoid groove HG can be suppressed. Therefore, it is possible to ensure highly accurate zoom lens driving even after the drop.

In FIG. 20, the sub-engagement groove DG includes a photographing area (21st area) DGA in which the sub-helicoid DH is positioned during photographing, and a non-photographing area in which the sub-helicoid DH is positioned during non-photographing (non-photographing). It has a region DGB. The sub helicoid DH is arranged in the non-imaging region DGB from the outside of the helicoid cylinder 230 through the introduction path DGC. The non-imaging area DGB may be provided with a transition area which is connected to the imaging area DGA and whose groove width gradually narrows as the distance from the imaging area DGA increases. In this case, the transition area becomes the 23rd area, and the non-imaging area DGB other than this transition area becomes the 22nd area. The relationship of the minimum gap Δ2 between the sub helicoid DH and the sub engagement groove DG in this case is the same as that of the above-described embodiment.

In the non-imaging region DGB, the sub helicoid DH relatively slides while being in contact with the sub engagement groove DG. Therefore, when the sub helicoid DH moves in the non-shooting area DGB to the side away from the shooting area DGA, the lens barrel is retracted, and if the digital still camera is accidentally dropped in such a state, The impact force can be suppressed by the auxiliary helicoid DH and the auxiliary engagement groove DG which are in contact with each other. On the other hand, in the imaging area DGA, the sub helicoid DH is in a state of not contacting the sub engagement groove DG, so that the zoom operation is not hindered. The other configuration is the same as that of the above-described embodiment.

As yet another embodiment, the helicoid HC may be in contact with the helicoid groove HG in both the shooting area HGA and the non-shooting area HGB. As a result, the helicoid HC is in contact with the helicoid groove HG and the sub-helicoid DH is in contact with the sub-engaging groove DG at the time of non-imaging, so that 6 pairs of helicoids are in contact with the groove. Therefore, when the digital still camera 1 is accidentally dropped, the impact force is dispersed and absorbed by the six pairs of helicoids and grooves, so that the zoom lens drive with high accuracy can be ensured even after the drop. .. Other effects are similar to those of the above-described embodiment.

1 Digital Still Camera 2 Imaging Unit 3 Camera Body 4 Flash Light Emitting Unit 5 Shutter Button 6 Display Unit 7 EVF
8 Changeover switch 9 Switch/zoom switch 100 Lens barrel 110 Outer fixed barrel 111 Guide groove 112 First holding frame 113 Second holding frame 114 Guide shaft 115 Third holding frame 115a Arm portion 116 Guide shaft 117 Fourth holding frame 118 5 holding frame 119 shutter mechanism 120 rectilinear barrel 121 projection 122 hole 122a diameter expansion hole 122b diameter reduction hole 130 rotating cylinder 131 cam groove 131A shooting area 131B non-shooting area 131C transition area 131a bottom surface 131b side surface 132 cam groove 132A shooting area 132B Non-shooting area 132C Transition area 132a Bottom surface 132b Side surface 133 Cam groove 133A Shooting area 133B Non-shooting area 133C Transition area 134 Cam groove 134A Shooting area 134B Non-shooting area 134C Transition area 135 Introducing path 140 Inner fixed tube 150 pin 150a Cylindrical part 150b Disk 150c truncated cone 160 pin 160a top surface 160b conical surface 170 pin 180 pin 230 helicoid cylinder DG sub-engagement groove DGA shooting area DGB non-shooting area DGC introduction path DH sub-helicoid HC helicoid HG helicoid groove HGA shooting area HGB non-shooting Region HGC Introductory path L1-L5 Lens group MT Motor Δ1 Minimum gap Δ2 Minimum gap

Claims (5)

In the lens barrel that holds the lens displaceably in the optical axis direction,
A tubular member having a main engagement groove and a sub engagement groove on the circumferential surface,
A frame member that includes a main engagement piece that engages with the main engagement groove, and a sub engagement piece that is disposed in the sub engagement groove.
The lens is held on at least one of the tubular member and the frame member,
When the tubular member and the frame member are relatively rotated, the main engaging piece relatively moves along the main engaging groove, and the sub engaging along the sub engaging groove. The pieces move relative to each other,
At the time of shooting, the sub-engaging piece is not in contact with the sub-engaging groove, the main engaging piece is in contact with the main engaging groove, thereby performing positioning of the lens in the optical axis direction,
A lens barrel in which the main engaging piece is in contact with the main engaging groove and the sub-engaging piece is in contact with the sub-engaging groove during non-shooting. In the lens barrel that holds the lens displaceably in the optical axis direction,
A tubular member having a main engagement groove and a sub engagement groove on the circumferential surface,
A frame member that includes a main engagement piece that engages with the main engagement groove, and a sub engagement piece that is disposed in the sub engagement groove.
The lens is held on at least one of the tubular member and the frame member,
When the tubular member and the frame member are relatively rotated, the main engaging piece relatively moves along the main engaging groove, and the sub engaging along the sub engaging groove. The pieces move relative to each other,
At the time of shooting, the main engagement piece is in contact with the main engagement groove to perform positioning of the lens in the optical axis direction,
The main engagement piece is in contact with the main engagement groove at the time of non-imaging, and the sub engagement piece is in contact with the sub engagement groove,
The sub-engagement groove connects the 21st area in which the sub-engagement piece is located during shooting, the 22nd area in which the sub-engagement piece is located during non-shooting, and the 21st area and the 22nd area. If the minimum gap between the 21st region and the sub-engagement piece is C and the minimum gap between the 23rd area and the sub-engagement piece is D, then C>D. A lens barrel that holds. The lens barrel according to claim 2 , wherein the minimum gap D decreases as the sub-engagement piece is displaced from the 21st region side to the 22nd region side. The Fukukakarigohen lens barrel according to any one of claims 1 to 3 not in contact with the sub-engaging groove at the time of shooting. The main engagement piece is a metal pin, the Fukukakarigohen the lens barrel according to any one of claims 1 to 4, which is a resin pin.

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