JP4139629B2 - Lens barrel drive - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a lens barrel drive device, and more particularly, to a lens barrel drive device used for equipment having an optical system.
[0002]
[Prior art]
The lens barrel driving device is used to adjust the position of a group of lenses constituting the imaging optical system with respect to a light receiving unit that captures a still image or a moving image. For example, a lens barrel driving device is used when a lens unit for zooming in a zooming mechanism of a camera is moved toward and away from the light receiving means.
In earlier lens barrel driving devices, the lens barrel is moved via a movable mechanism that moves the lens barrel along the center line direction of the fixed cylinder holding the light receiving means such as a light receiving element on the inner bottom surface thereof. It was supported. Such a movable mechanism has a movable cylinder that supports the lens barrel, and this movable cylinder is supported by a helicoid screw inside the fixed cylinder. Thus, by rotating the movable cylinder, the movable cylinder moves along the direction of the rotation center line, and accordingly, the lens barrel contacts and separates from the light receiving element.
[0003]
However, since the above configuration employs a helicoid screw, the moving direction and moving speed of the lens barrel are constant and can be changed as long as the movable cylinder is rotated in a constant direction at a constant speed. There wasn't. For cameras that shoot on film, zooming can be achieved simply by moving the zoom lens group in a certain direction, so the above configuration is sufficient, but an image sensor such as a CCD is received. In the case of a so-called digital camera or digital video camera used as a means, the moving direction of the zooming lens may be reversed in the process of zooming operation, and the above configuration is the reverse of the moving direction. It was not suitable for switching.
[0004]
Therefore, another conventional lens barrel drive device adopts a configuration in which the lens barrel is supported by a cam mechanism instead of the movable mechanism. Such a cam mechanism has a cam cylinder that supports the lens barrel and has a driven protrusion on the outer peripheral surface thereof, and is configured to be engaged with a cam groove provided on the inner peripheral surface of the fixed cylinder. . By adopting such a configuration, even when the cam cylinder is rotated at a constant direction and at a constant speed, by changing the direction of the cam groove with respect to the peripheral surface as appropriate, the change in the forward / reverse direction of the movement of the cam cylinder is changed. And it was possible to realize a change in moving speed.
[0005]
[Problems to be solved by the invention]
By the way, in recent years, it is required to drive the lens barrel without causing a rotation operation around the optical axis of the lens group supported by the lens barrel. Therefore, even in the case of the conventional barrel driving device, in order to meet such a demand, the barrel is rotatably supported with respect to the cam barrel, and the barrel is rotated along with the rotation of the cam barrel. In order to prevent rotation, the key member is bitten between the lens barrel and the fixed barrel. The key groove into which the key member is fitted is formed over the entire movement range of the lens barrel along the center line direction on the inner peripheral surface of the fixed cylinder so as not to prevent the movement of the lens barrel with respect to the light receiving means. It had been.
On the other hand, a cam groove that engages a driven projection of the cam cylinder is also formed on the inner peripheral surface of the fixed cylinder. Since the cam groove is formed in a direction slightly inclined in the direction of the center line from the circumferential direction of the inner peripheral surface, if the entire length is set long, the cam groove intersects with the key groove. In such a case, when the driven projection moves along the cam groove and passes through the intersection with the key groove, the driven projection is detached from the cam groove, resulting in a malfunction.
[0006]
For this reason, in the conventional lens barrel drive device, in order to avoid the intersection of the key groove and the cam groove, the inclination angle of the cam groove in the center line direction must be set large, thereby making the more complicated There are inconveniences that it is difficult to perform an operation with high accuracy and that the smoothness of the operation is lowered.
[0007]
It is an object of the present invention to provide a lens barrel drive device that improves the disadvantages of the conventional example and can cope with complicated operations. Another object is to improve the operation accuracy. Another object is to improve the smoothness of operation.
[0008]
[Means for Solving the Problems]
According to the first aspect of the present invention, the lens barrel (110, 120) holding the lens group (111, 121) is moved along the optical axis with respect to the light receiving means (100) arranged on the optical axis. A lens barrel drive device (10) for holding a light receiving means therein (20), a cam mechanism (30) for moving the lens barrel at a predetermined displacement along the optical axis direction, Rotation restricting means (40) for restraining the rotation of the lens barrel relative to the housing.
The cam mechanism includes a cam cylinder (31) that is rotatably arranged inside the casing with its outer peripheral surface facing the inner peripheral surface of the casing, and supports the lens barrel, and the cam cylinder. And a cam groove portion (33) for forming a cam groove for guiding the driven protrusion on the inner peripheral surface of the housing.
Further, the rotation restricting means includes a key member (43) provided between the lens barrel and the casing, and an inner peripheral surface of the casing. Linear along the optical axis A key groove (41) that forms a key groove, and the cam groove and the key groove intersect And the keyway is deeper than the cam groove. Is formed.
Further, in addition to the above configuration, when the driven projection is at a position passing through the intersection (S) between the cam groove and the key groove, the guide means (50) guides the cam cylinder in the same direction as the intersection of the cam groove. ).
[0009]
In the above configuration, the lens barrel is supported by the cam barrel of the cam mechanism. On the other hand, the casing has an inner peripheral surface with which the outer peripheral surface of the cam cylinder is in sliding contact, and the cam cylinder is rotatably supported by the casing. Then, there are driven projections on the outer peripheral surface of the cam cylinder, and there are cam groove portions on the inner peripheral surface of the housing. Therefore, by rotating the cam cylinder, the cam cylinder is made to respond to displacement in the center line direction of the cam groove. Can be moved in the same direction.
[0010]
On the other hand, the lens barrel supported by the cam barrel moves in the direction of the center line together with the cam barrel, but since the rotation operation is restricted by the key member of the rotation restricting means, the lens barrel rotates as the cam barrel rotates. Never do.
Furthermore, the cam groove is provided on the inner peripheral surface of the housing so as to intersect with the key groove. When the driven projection passes through these intersecting portions, the cam cylinder passes through the driven projection at the intersecting portion. Since the guide means guides the cam barrel along the same direction as the direction in which the guide is guided, the driven projection passes through the intersection without deviating from the cam groove, and the cam barrel and the lens barrel are continuously passed through the driven projection. Are guided in a direction along the cam groove.
[0011]
The invention according to claim 2 has the same configuration as that of the invention according to claim 1, and the guide means is on either one of the outer peripheral surface of the cam cylinder and the inner peripheral surface of the housing. It has a configuration in which an engaging protrusion (51) provided and a guide groove (52) for forming a guide groove for guiding the engaging protrusion on the other surface are provided.
[0012]
In the above configuration, any of the engagement protrusion and the guide groove may be provided as long as the engagement protrusion and the guide groove are provided separately on the inner peripheral surface of the housing and the outer peripheral surface of the cam cylinder.
In the above configuration, the same operation as that of the first aspect of the invention is performed, and when the driven projection passes through the intersection of the cam groove and the key groove, the cam cylinder is guided through the driven projection at the intersection. Since the engaging protrusion is guided along the guide groove along the same direction as the direction of being driven, the driven protrusion passes through the intersection without deviating from the cam groove, and as a result, continuously through the driven protrusion. The cam barrel and the lens barrel are guided in a direction along the cam groove.
[0013]
The invention described in claim 3 has the same configuration as that of the invention described in claim 1 or 2, and includes a plurality of lens barrels, and each of these lens barrels is supported inside the cam cylinder, The lens barrel cam mechanism (60, 70) that causes a predetermined displacement along the optical axis direction by rotation of the cam barrel is provided between the outer peripheral surface of each barrel and the inner peripheral surface of the cam barrel. The composition is taken.
[0014]
In the above configuration, the same operation as that of the first or second aspect of the invention is performed, and a plurality of lens barrels are supported by the cam barrel. Further, between each lens barrel and the cam barrel, a lens barrel cam mechanism that generates a unique displacement along the optical axis direction for each lens barrel is provided corresponding to each lens barrel individually. Since each lens barrel is restricted in rotation by the rotation restricting means, when the cam barrel is rotated, it does not rotate with the cam barrel, and a unique displacement is caused for each barrel along the optical axis direction. Will occur. On the other hand, since the cam barrel itself is displaced along the center line direction by the cam mechanism, each lens barrel has a combined displacement of the displacement of the cam barrel and the displacement generated for each barrel relative to the light receiving means. It becomes. For this reason, when light is received by the light receiving means through a plurality of lens groups, if the position of one lens group is determined, the other lens groups can be arranged at appropriate positions corresponding to this. Positioning associated with each lens group is also possible.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
(Overall configuration of the embodiment)
An embodiment of the present invention will be described with reference to FIGS. In the present embodiment, a case where the lens barrel driving device 10 is applied to a zooming mechanism of a digital camera will be described as an example. FIG. 1 is a cross-sectional view along the optical axis of the lens groups 111 and 121 of the lens barrels 110 and 120 supported by the lens barrel driving apparatus 10 according to this embodiment (more precisely, a cross section along the line XX in FIG. 3). FIG. 2 is a cross-sectional view showing a retracted state, and FIG. 3 is a partially cutaway view along a plane perpendicular to the optical axis. It is explanatory drawing shown.
In the following description, a state in which the digital camera can capture the widest range of subjects is referred to as a wide state (a state in which imaging can be performed in the widest range), and a state in which the subject can be captured at the highest magnification in the narrowest range. Is called a tele state (a state in which imaging can be performed in the narrowest range), and when the digital camera is not used, each of the lens barrels 110 and 120 and a cam barrel 31 to be described later are all stored in a fixed barrel 20 to be described later. The state is called a retracted state.
[0016]
The lens barrel drive device 10 includes a first lens barrel 110 that holds the first lens group 111 for zooming and a second lens barrel 120 that holds the second lens group 121 for zooming. In addition to supporting the optical axes of all the lenses in the lens groups 111 and 121 to be on the same axis, the lens barrels 110 and 120 are positioned so as to be arranged in accordance with each magnification.
[0017]
In order to realize the above function, the lens barrel driving device 10 moves the fixed cylinder 20 as a housing for holding the light receiving element 100 and the lens barrels 110 and 120 with a predetermined displacement along the optical axis direction. The cam mechanism 30, a drive mechanism 90 that is a driving source for moving the lens barrels 110 and 120 by the cam mechanism 30, and a rotation restricting unit that prevents the rotation of the lens barrels 110 and 120 relative to the fixed barrel 20 40, guide means 50 for assisting the movement of the respective lens barrels 110 and 120 by the cam mechanism 30, and a first mirror for applying a displacement in the optical axis direction inherent to the first lens barrel 110 to the cam barrel 31 described later. Holds a barrel cam mechanism 60, a second barrel cam mechanism 70 that imparts a displacement in the optical axis direction inherent to the second barrel 120 to the cam barrel 31, and a third lens group 131 for focusing. Focusing the lens barrel 130 And a third lens driving unit 80 for moving and positioning along the optical axis direction for Align. Hereinafter, each part will be described in detail.
[0018]
(Fixed cylinder)
The fixed cylinder 20 constitutes a bottomed casing in which a substantially cylindrical tubular portion and a bottom plate that closes one end of the tubular portion are integrally connected and the other end is opened. is doing. The open end of the fixed cylinder 20 is directed toward the subject when the digital camera is photographing.
At the center of the inner bottom surface of the fixed cylinder 20 (the inner surface of the bottom plate), the image sensor 100 is held with its light receiving surface facing the opening end side. Further, on the inner peripheral surface of the fixed cylinder 20, three key groove portions 41 described later of the rotation restricting means 40 are formed at intervals of 120 ° with respect to the center line of the fixed cylinder 20. Further, three cam groove portions 33 (to be described later) of the cam mechanism 30 are also formed on the inner peripheral surface at intervals of 120 ° with respect to the center line of the fixed cylinder 20.
The center line of the fixed cylinder 20, the center line of the cam cylinder 31 described later, the center line of the key ring member 42 described later, the center line of the first lens barrel 110, the center line of the second lens barrel 120, and the Each part is set so that the optical axis of one lens group 111, the optical axis of the second lens group 121, and the optical axis of the third lens group 131 are all on the same straight line.
[0019]
(Cam mechanism)
The cam mechanism 30 is a cylindrical body whose both ends are opened, and a cam cylinder 31 that supports the first lens barrel 110 and the second lens barrel 120 therein, and an outer peripheral surface of the cam cylinder 31. And a cam groove portion 33 that forms a cam groove engaged with the driven protrusion 32 on the inner peripheral surface of the fixed cylinder 20.
[0020]
The outer diameter of the cam cylinder 31 is set to be slightly smaller than the inner diameter of the fixed cylinder 20, and the inner surface of the fixed cylinder 20 is opposed to the inner peripheral surface of the fixed cylinder 20. It is arrange | positioned so that rotation is possible. The cam cylinder 31 is disposed inside the fixed cylinder 20 such that the center line is on the same axis as the fixed cylinder 20 and can move along the center line direction. Yes. The cam cylinder 31 is rotatable inside the fixed cylinder 20 and movable in the center line direction by the configuration of the rotation restricting means 40 described in detail later.
Further, the length of the cam tube 31 in the center line direction is substantially equal to the length of the fixed tube 20, and when the lens barrel drive device 10 is in the retracted state, the entire length is stored in the fixed tube 20. In the case of the wide state, the fixed tube 20 protrudes to the outside from the open end portion to the maximum extent.
[0021]
The driven protrusion 32 and the cam groove portion 33 will be described with reference to FIGS. 4-7 is explanatory drawing which developed the side surface of the fixed cylinder 20 in the shape of a belt, and represents the position change of the cam cylinder 31 and the driven projection 32 in the process of shifting from the wide state to the retracted state in the order of FIGS. Yes.
The driven protrusion 32 is provided in the vicinity of the end on the back side in a state in which the cam cylinder 31 is stored in the fixed cylinder 20 and protrudes outward from the outer peripheral surface thereof. An infinite number of gear teeth as a driven portion 91 of a drive mechanism 90 to be described later are formed on the outer peripheral surface on the back side of the cam cylinder 31, and the driven projection 32 protrudes further to the outside of the teeth.
Further, three follower protrusions 32 are provided at intervals of 120 ° on the same circumference with the center line of the cam cylinder 31 as the center.
[0022]
The cam groove 33 is formed with a cam groove having a cross section corresponding to the tip of the driven protrusion on the inner peripheral surface of the fixed cylinder 20. As shown in FIGS. 4 to 7, the cam groove portion 33 is inclined more in the center line direction than the circumferential direction of the inner peripheral surface of the fixed cylinder 20. By adopting such a shape, the distal end portion of the driven projection 32 is inserted and the cam cylinder 31 is rotated so that the driven projection 32 moves along the cam groove portion 33 and follows this. The cam cylinder 31 also moves along the center line direction while rotating. Further, when the cam cylinder 31 is rotated at a constant angular velocity in a constant direction, the cam cylinder 31 moves forward and backward along the center line according to the inclination angle in the center line direction at each part of the cam groove portion 33 as shown in the figure. The movement of the direction is switched or the movement displacement is changed.
Further, in the cam groove portion 33, when there is a follower protrusion 32 at the position shown in FIG. 4, a wide state is reached, and a state in which the follower protrusion 32 is moved to the right in FIG. .
Similar to the driven protrusion 32, three cam groove portions 33 are provided on the inner peripheral surface of the fixed cylinder 20 at intervals of 120 ° centering on the center line.
[0023]
(Drive mechanism)
As shown in FIG. 3, the drive mechanism 90 is provided on the outer peripheral surface of the fixed cylinder 20 (not shown in FIGS. 1 and 2). The drive mechanism 90 includes a driven portion 91 that is a gear tooth formed by making a round on the outer peripheral surface of the cam cylinder 31 described above, a small-diameter main drive gear 92 that meshes with the driven portion 91, and the main drive A stepping motor (not shown) that rotationally drives the gear 92.
[0024]
The main driving gear 92 is rotatably mounted outside the fixed cylinder 20 (see FIG. 3), and the driven portion 91 inside the fixed cylinder 20 is passed through a through hole 94 that penetrates the side wall surface of the fixed cylinder 20. Are engaged.
Further, since the cam cylinder 31 moves in the direction of the center line as described above, the main driving gear 92 is divided into three parts corresponding to this, and they are arranged along the center line direction of the fixed cylinder 20 of the cam cylinder. It is divided and arranged within a range that can cover 31 movements (see FIG. 4).
[0025]
(Rotation restricting means)
The rotation restricting means 40 includes a cylindrical key ring member 42 that is rotatably supported with respect to the cam cylinder 31 inside the cam cylinder 31, and an end (key ring member 42) on the back side of the key ring member 42. A key member 43 provided with a convex portion 43a that is fixedly mounted on the back of the cam barrel 31 and protrudes to the outside of the cam barrel 31, and a convex portion 43a. And a key groove portion 41 that forms a key groove on the inner peripheral surface of the fixed cylinder 20.
[0026]
The key ring member 42 is provided with a flange 42a at the back end portion thereof, and the front end portion of the flange 42a is fitted into a circumferential groove formed on the inner peripheral surface at the back end portion of the cam cylinder 31. The cam cylinder 31 can be rotated. On the other hand, the key ring member 42 can be moved along the center line direction by the key member 43, but is supported so as not to rotate with respect to the fixed cylinder 20. Therefore, when the cam cylinder 31 is rotationally driven and moves along the center line direction, the key ring member 42 follows the movement along the center line direction but does not rotate.
[0027]
Further, the cam cylinder 31 and the key ring member 42 are arranged and set so that their center lines are on the same axis. The key ring member 42 has a length in the center line direction slightly shorter than the cam cylinder 31, and the key ring member 42 and the cam cylinder 31 are arranged so that the end surfaces of the respective rear side end portions are aligned on the same plane. Has been. Further, a gap is formed between the outer peripheral surface of the key ring member 42 and the inner peripheral surface of the cam barrel 31, and the cylindrical side wall portion of the first lens barrel 110 is inserted.
The first lens barrel key member 44 projecting toward the key ring member 42 is provided on the inner peripheral surface of the cylindrical side wall portion of the first lens barrel 110. On the outer peripheral surface of the key ring member 42, a first lens barrel key groove portion 45 is provided that forms a key groove along the center line direction. Accordingly, when the first lens group 111 is moved, the first lens barrel 110 is guided by the first lens barrel key member 44 along the first lens barrel key groove 45, thereby causing the key ring member to move. No rotational displacement occurs with respect to 42 and the fixed cylinder 20.
The first lens barrel key member 44 and the first lens barrel key groove 45 have different angular arrangements that do not appear in the cross sections of FIGS. 1 and 2 with respect to the center line. For convenience, the two-dot chain line is used in FIGS.
[0028]
Further, a second lens barrel 120 is disposed inside the key ring member 42, and the second lens barrel 120 will be described later and projects to the inner peripheral surface of the cam tube 31 toward the radially outer side. Three driven projections 71 are provided. Each of the key ring members 42 has guide holes 46 for causing the driven projections 71 to function as key members for restricting the second lens barrel 120 from rotating relative to the key ring member 42. Three are provided corresponding to the driven protrusions 71. The guide hole 46 is a through hole provided in the center line direction from the back end portion of the key ring member 42, and the second lens barrel 120 is inserted by inserting the substantially rod-shaped driven projection 71. When the second lens group 121 is moved, the driven projection 71 is guided along the guide hole 46 so that the key ring member 42 and the fixed barrel 20 are not rotationally displaced.
[0029]
The key groove portion 41 forms a key groove on the inner peripheral surface of the fixed cylinder 20 along the center line direction of the fixed cylinder 20. Three such key groove portions 41 are also provided at an angular interval of 120 ° with respect to the center line of the fixed cylinder 20. And these key groove parts 41 cross | intersect the cam groove part 33 mentioned above, as shown in FIG.
[0030]
On the other hand, the key member 43 is a substantially annular flat plate, and is fixedly mounted on the back end surface of the key ring member 42 as described above. Since the convex portion 43a projecting outward in the radial direction of the key member 43 is inserted into the key groove portion 41 on the outer peripheral surface of the fixed cylinder 20, the key ring member 42 has The rotation is prevented and the movement along the center line direction is guided.
[0031]
(Guide means)
As described above, the cam groove portion 33 of the cam mechanism 30 and the key groove portion 41 of the rotation restricting means 40 intersect each other. Therefore, in the cam cylinder 31 in which the driven projection 32 follows the cam groove portion 33 and is displaced in the center line direction, the driven projection 32 approaches the intersection S (see FIGS. 5 and 6) of the cam groove portion 33 and the key groove portion 41. The driven protrusion 32 falls off from the cam groove 33, and there is a possibility that the driven protrusion 32 may be in a malfunction.
The guide means 50 is for eliminating the above-described malfunction, and has a function of guiding the cam cylinder 31 in an intended direction in advance when the driven protrusion 32 reaches the intersection S.
[0032]
That is, the guide means 50 includes an engaging protrusion 51 that protrudes toward the center on the inner peripheral surface of the fixed cylinder 20 and a guide groove portion 52 that forms a guide groove on the outer peripheral surface of the cam cylinder 31. ing.
As shown in FIGS. 5 and 6, the guide groove 52 forms a guide groove so that the cam groove 33 coincides with the direction in which the cam cylinder 31 is guided via the driven projection 32 at the intersection S. The engaging projection 51 is also provided with its longitudinal direction facing the same direction as the guide groove 52.
[0033]
Further, as described above, the guide means 50 achieves its purpose if it guides the movement of the cam cylinder 31 at least until the driven projection 32 has passed from before the intersection S of the cam groove 33 until it has passed. The guide groove 52 is formed with a length substantially the same as the length of the intersection S of the cam groove 33.
Three guide groove portions 52 are provided at an interval of 120 ° on the same circumference centered on the center line of the cam cylinder 31, and the engagement protrusions 51 are also centered on the center line of the fixed cylinder 20. Three are provided at intervals of 120 ° on the same circumference.
[0034]
Note that the engagement protrusion 51 and the guide groove 52 may be arranged so that the engagement protrusion 51 and the guide groove 52 can engage with each other until the driven protrusion 32 finishes passing from before the intersection S of the cam groove 33, and particularly the arrangement shown in FIGS. It is not limited to. Further, the engaging protrusion 51 may be provided on the outer peripheral surface of the cam cylinder 31 and the guide groove 52 may be provided on the inner peripheral surface of the fixed cylinder 20.
[0035]
(First and second lens barrel)
The first lens barrel 110 is formed in a cylindrical shape, and a first lens group 111 is held at the center of one end. Further, a caliper ring 112 and a barrier mechanism 113 are attached to the end of the first lens barrel 110 where the first lens group 111 is provided.
As described above, the first lens barrel 110 is set such that the outer diameter and inner diameter of the first lens barrel 110 can be inserted into the gap between the cam cylinder 31 and the key ring member 42. In a state where the first lens barrel 110 is inserted and supported in the gap, the first lens barrel key member 44 and the first lens barrel key groove portion 45 described above are attached to the key ring member 42. Is non-rotatable and can only move along its centerline.
[0036]
The second lens barrel 120 is formed in a cylindrical shape, and a second lens group 121 is held at the center of one end. A shutter stop mechanism 122 is provided on the end of the second lens barrel 120 where the second lens group 121 is provided. Reference numeral 11 in FIGS. 1 and 2 denotes a flexible substrate for transmitting / receiving a drive command signal of the shutter mechanism 122, and a fixed cylinder through a not-shown groove for inserting a substrate provided in the key ring member 42 and the key groove portion 41. It is wired to 20 outside.
The second lens barrel 120 is disposed on the inner side at the back end of the key ring member 42, and is supported by the cam barrel 31 via the second lens barrel cam mechanism 70. As described above, the second lens barrel 120 cannot rotate with respect to the key ring member 42 by the driven projection 71 of the second lens barrel cam mechanism 70 and the guide hole 46 of the key ring member 42. However, only movement along the center line direction is possible.
[0037]
(First barrel cam mechanism and second barrel cam mechanism)
The first lens barrel cam mechanism 60 is provided between the first lens barrel 110 and the cam barrel 31, and the first lens barrel 110 is predetermined in the center line direction according to the rotation amount of the cam barrel 31. Position to the position. The first lens barrel cam mechanism 60 forms a cam groove in which the driven projection provided on the outer peripheral surface of the first lens barrel 110 engages with the driven projection on the inner peripheral surface of the cam barrel 31. And a cam groove portion (not shown). Since the cam barrel 31 itself is displaced in the center line direction according to the cam groove portion 33 by its own rotation, the first lens group 111 supported by the first lens barrel 110 is rotated by the rotation of the cam barrel 31. A combined displacement between the cam mechanism 30 and the first barrel cam mechanism 60 is produced.
[0038]
On the other hand, the second barrel cam mechanism 70 is provided between the second barrel 120 and the cam barrel 31, and moves the second barrel 120 in the center line direction according to the rotation amount of the cam barrel 31. Is positioned at a predetermined position. The second lens barrel cam mechanism 70 includes a cam groove in which the driven protrusion 71 provided on the outer peripheral surface of the second lens barrel 120 and the driven protrusion 71 on the inner peripheral surface of the cam cylinder 31 engage. And a cam groove 72 that forms the shape. Since the cam barrel 31 is displaced in the center line direction by its own rotation as described above, the second lens group 121 supported by the second lens barrel 120 is camped by the rotation of the cam barrel 31. A combined displacement between the mechanism 30 and the second barrel cam mechanism 70 is produced.
[0039]
The first lens group 111 and the second lens group 121 have a function of changing the imaging magnification according to the distance to the light receiving element 100. When the distance between one lens group is determined, the distance between the other lens group is determined. Is appropriately determined. Accordingly, the cam groove portions of the first and second lens barrel cam mechanisms 60 and 70 have a groove direction in consideration of the movement of the cam barrel 31 so as to satisfy the relative distance conditions of these lens groups. It has been decided. Accordingly, by rotating the cam cylinder 31 by the drive mechanism 90, the imaging magnification is appropriately changed, and the lens groups 111 and 121 are positioned so as to enable good imaging at the magnification. It becomes.
The first lens barrel cam mechanism 60 has a different angular arrangement that does not appear in the cross section of FIGS. 1 and 2 with respect to the center line. Displayed with a dotted line.
[0040]
(Third lens barrel and third lens driving means)
The third lens barrel 130 holding the third lens group 131 for performing focusing is disposed inside the fixed cylinder 20 and in front of the light receiving element 100 via the third lens driving means 80. ing. The third lens driving means 80 includes a stepping motor 81, a feed screw mechanism 82 that moves the third lens barrel 130 along the optical axis direction of the third lens group 131 by the rotational driving of the stepping motor 81, and a third screw driving mechanism 82. And a guide means (not shown) for linearly moving the lens barrel 130 along the optical axis. The distance from the third lens group 131 to the light receiving element 100 is appropriately determined in consideration of the distance from the first and second lens groups 111 and 121 to the light receiving element. Therefore, the third lens driving unit 80 detects the amount of rotation of the stepping motor of the driving mechanism 90, determines the driving amount of the stepping motor 81, and moves the third lens group 131 to an appropriate position on the optical axis. Position it.
[0041]
(Operation of the embodiment)
When the cam cylinder 31 is rotated by driving of the drive mechanism 90 from the retracted state shown in FIGS. 2 and 7, the driven projection 32 moves along the cam groove portion 33 in the lens barrel driving device 10 having the above configuration. The cylinder 31 moves along the center line direction with the rotation operation. In the course of moving the cam cylinder 31 from the retracted state to the wide state shown in FIGS. 1 and 4, the driven protrusion 32 approaches the intersection S of the cam groove 33.
[0042]
At that time, as shown in FIG. 6, in the guide means 50, the engaging protrusion 51 starts to engage with the guide groove 52 on the cam cylinder 31 side, and the driven protrusion 32 finishes passing through the intersection S. As shown in FIG. 5, the cam cylinder 31 is fed in a predetermined direction by the guide means 50. Therefore, the cam cylinder 31 is smoothly fed even when the driven protrusion 32 passes through the intersection S.
[0043]
As the cam barrel 31 moves, the first barrel cam mechanism 60 moves the first barrel 110 in a direction protruding from the cam barrel 31 and positions the first barrel 110 in a wide state. Further, the second lens barrel 120 is also positioned at a predetermined position where the second lens barrel 120 is in the wide state by the second lens barrel cam mechanism 70.
[0044]
When shifting from the wide state to the tele state, the cam cylinder 31 is further rotated by the drive mechanism 90, and the cam cylinder 31 and the lens barrels 110 and 120 are temporarily moved to the fixed cylinder 20 side according to the shape of the cam groove 33. And move again in the protruding direction. Then, the lens barrels 110 and 120 are positioned at positions suitable for the tele state by the synthetic positional displacement of the cam mechanism 30 and the lens barrel cam mechanisms 60 and 70.
[0045]
(Effect of embodiment)
When the driven projection 32 of the cam mechanism 30 passes through the intersection S between the cam groove portion 33 and the key groove portion 41, the lens barrel drive device 10 guides the cam barrel 31 in a predetermined direction by guide means 50 independent of the cam mechanism 30. Therefore, it is possible to effectively avoid the occurrence of a malfunction in the feeding operation of each of the lens barrels 110 and 120 due to the presence of such an intersection S, to facilitate the feeding operation, and to improve reliability. Is possible.
[0046]
Further, since the cam means 33 can be provided across the key groove portion 41 on the inner peripheral surface of the fixed cylinder 20 due to the presence of the guide means 50, the cam groove is inclined in the circumferential direction and formed with a gentler inclination. Thus, the feeding operation of each of the lens barrels 110 and 120 can be performed smoothly. Further, since the amount of movement of each barrel 110, 120 in the optical axis direction can be reduced with respect to the amount of rotation of the cam barrel 31, the barrels 110, 120 can be positioned more accurately.
Further, the arrangement of the driven protrusions 32 in the wide state and the tele state is the same side with respect to the intersection S in the cam groove 33 (the driven protrusion 32 is located on the right side of the intersection S in both states in FIG. 4). Therefore, it is not necessary to increase the processing accuracy of the engaging projections 51 and the guide groove portions 52 of the guide means 50 in the process of zooming, and the productivity can be improved.
[0047]
Further, in the lens barrel driving device 10, since the two lens barrels 110 and 120 are engaged with the cam barrel via the lens barrel cam mechanisms 60 and 70, respectively, if the cam barrel 31 is driven to rotate, The lens barrels 110 and 120 can be positioned appropriately, and productivity can be improved by reducing the number of parts.
[0048]
【The invention's effect】
In the present invention, the cam cylinder is guided in a predetermined direction by guide means independent of the cam mechanism when the driven projection of the cam mechanism passes through the intersection of the cam groove and the key groove. It is possible to effectively avoid the occurrence of malfunctions in the cylinder feeding operation, smooth the feeding operation, and improve the reliability.
Furthermore, since the cam groove portion can be provided across the key groove portion on the inner peripheral surface of the housing, the cam groove can be formed in a more gentle inclination by inclining in the circumferential direction, and the feeding operation of the lens barrel can be performed. It becomes possible to carry out smoothly. In addition, since the amount of movement of the lens barrel in the optical axis direction can be reduced with respect to the amount of rotation of the cam barrel, the lens barrel can be positioned more accurately.
Further, it is possible to eliminate the necessity of designing the lens group so as to correspond to the cam groove having a tight inclination as in the prior art.
[0049]
In addition, when a configuration is provided in which a plurality of lens barrels are provided and a lens barrel cam mechanism is provided for each lens barrel, each lens barrel can be appropriately positioned only by rotating the cam barrel, and the number of parts can be reduced. It becomes possible to improve the productivity.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view along the optical axis of a lens group of a lens barrel supported by a lens barrel driving apparatus according to an embodiment of the present invention, showing a case in a wide state.
FIG. 2 is a cross-sectional view along the same plane as FIG. 1 and shows a case in a retracted state.
FIG. 3 is an explanatory view showing a state in which a part is cut out along a plane perpendicular to the optical axis of the lens group of the lens barrel driving device;
FIG. 4 is an explanatory diagram in which the side surface of the fixed cylinder is developed in a band shape, and shows the positions of the cam cylinder and the driven projection in the wide state.
FIG. 5 is an explanatory diagram in which the side surface of the fixed cylinder is developed in a band shape, and shows the positions of the cam cylinder and the driven protrusion in the process of shifting from the wide state to the retracted state.
6 is an explanatory diagram in which the side surface of the fixed cylinder is developed in a band shape, and shows the position change of the cam cylinder and the driven projection following FIG. 5 in the process of shifting from the wide state to the retracted state.
FIG. 7 is an explanatory diagram in which the side surface of the fixed cylinder is developed in a band shape, and shows the positions of the cam cylinder and the follower projection in the retracted state.
[Explanation of symbols]
10 Lens barrel drive
20 Fixed cylinder (housing)
30 Cam mechanism
31 Cam cylinder
32 Follower projection
33 Cam groove
40 Rotation restricting means
41 Keyway
43 Key members
50 Guide means
51 engaging protrusion
52 Guide groove
60 First lens barrel cam mechanism
70 Second lens barrel cam mechanism
100 Light receiving element (light receiving means)
110 First barrel
111 First lens group
120 Second barrel
121 Second lens group
S intersection

Claims (3)

A lens barrel driving device that moves a lens barrel holding a lens group along a light receiving means arranged on the optical axis along the optical axis,
A housing for holding the light receiving means therein;
A cam mechanism for moving the lens barrel at a predetermined displacement along the optical axis direction;
A rotation restricting means for restricting the rotation of the lens barrel with respect to the housing;
The cam mechanism is rotatably disposed inside the casing with its outer peripheral surface facing the inner peripheral surface of the casing, and supports the barrel, and an outer periphery of the cam cylinder A follower projection provided on the surface, and a cam groove portion that forms a cam groove for guiding the follower projection on the inner peripheral surface of the housing;
The rotation restricting means includes a key member provided between the lens barrel and the housing, and a key groove portion that forms a linear key groove along the optical axis on the inner peripheral surface of the housing. Have
The cam groove and the key groove intersect and the key groove is formed deeper than the cam groove ,
A mirror having guide means for guiding the cam cylinder in the same direction as the intersecting portion of the cam groove when the driven projection is at a position passing through the intersecting portion of the cam groove and the key groove. Tube drive device. The guide means guides the engagement protrusion provided on one surface between the outer peripheral surface of the cam cylinder and the inner peripheral surface of the housing and the engagement protrusion on the other surface. The lens barrel drive device according to claim 1, further comprising a guide groove portion that forms a guide groove to be formed. A plurality of the lens barrels are provided, and all of these lens barrels are supported inside the cam barrel,
A lens barrel cam mechanism for causing a predetermined displacement along the optical axis direction by rotation of the cam barrel for each of the lens barrels is provided between the outer peripheral surface of the lens barrel and the inner peripheral surface of the cam barrel. The lens barrel drive device according to claim 1, further comprising:

Images