JP6843589B2 - Lens barrel and imaging device - Google Patents

Description

The present invention relates to a zoom-type lens barrel mounted on an image pickup device such as a digital camera, and an image pickup device including a zoom-type lens barrel.

It has been proposed that a zoom-type lens barrel mounted on an imaging device such as a digital camera moves the lens holder engaged with the cam groove of the cam cylinder in the optical axis direction by rotating the cam cylinder. (Patent Document 1). In this proposal, the driving force of the motor unit provided on the outer side in the radial direction of the cam cylinder is decelerated via the gear train and transmitted to the cam cylinder, whereby the cam cylinder is rotationally driven.

Further, a zoom type lens barrel has been proposed in which a lens holder movably supported in the optical axis direction by a guide bar is driven in the optical axis direction by a driving device such as a stepping motor (Patent Document 2). In this proposal, stepping motors are provided for the number of a plurality of lens groups constituting the photographing optical system, and each lens group is driven independently.

Japanese Unexamined Patent Publication No. 2015-4759 Japanese Unexamined Patent Publication No. 2007-271649

However, in Patent Document 1, since the cam cylinder that drives the lens holder in the optical axis direction is rotationally driven by a motor unit provided on the radial outside of the cam cylinder, it causes an increase in the diameter of the lens barrel. Become. On the other hand, in Patent Document 2, although there is a degree of freedom in shape such that the shape of the lens barrel does not have to be cylindrical, stepping motors are required for the number of a plurality of lens groups, and as a result, the lens mirror There is a problem that the cylinder becomes large and the control of the motor becomes complicated.

Therefore, an object of the present invention is to provide a technique for realizing miniaturization of a lens barrel without complicating the control of a driving device for moving a plurality of optical members in the optical axis direction.

In order to achieve the above object, the lens barrel of the present invention includes a first optical member that moves in the optical axis direction of the lens barrel, a second optical member that moves in the optical axis direction, and the first optical member. A cam member that is cam-engaged with each of the optical member and the second optical member, is arranged parallel to the optical axis and is rotatably held, and a linear actuator that drives the first optical member. The cam member is rotated by a cam action between the cam member and the first optical member that moves in the optical axis direction by the linear actuator, and the second optical member is rotated by the cam member. As a result, the second optical member and the cam member move in the optical axis direction due to the cam action, and the cam member is arranged on the outer peripheral portion of the first optical member.

According to the present invention, it is possible to reduce the size of the lens barrel without complicating the control of the driving device for moving the plurality of optical members in the optical axis direction.

It is sectional drawing of the lens barrel which is 1st Embodiment of this invention. It is a graph which shows the relationship between the movement amount from the initial position of the 1st to 5th optical units, and the position in the optical axis direction. It is a perspective view which shows the main part of the lens barrel which is 2nd Embodiment of this invention. FIG. 5 is a schematic cross-sectional view taken along the optical axis direction at the position of the camshaft when the lens barrel shown in FIG. 3 is in the wide position. FIG. 5 is a schematic cross-sectional view taken along the optical axis direction at the position of the camshaft when the lens barrel shown in FIG. 3 is in the tele position. It is a graph which shows the relationship between the movement amount from the initial position of the 2nd to 4th optical units, and the position in the optical axis direction. It is a perspective view which shows the main part of the lens barrel which is the 3rd Embodiment of this invention. It is a perspective view which looked at the lens barrel shown in FIG. 7 from the back side. FIG. 5 is a schematic cross-sectional view taken along the optical axis direction at the position of the camshaft when the lens barrel shown in FIG. 7 is in the wide position. FIG. 5 is a schematic cross-sectional view taken along the optical axis direction at the position of the camshaft when the lens barrel shown in FIG. 7 is in the tele position. It is a schematic diagram when the cam part of a camshaft is developed with a predetermined diameter. It is a schematic diagram explaining the molding method of a camshaft. It is a schematic diagram explaining the molding method of a camshaft. FIG. 5 is a schematic cross-sectional view taken along the optical axis direction at the position of the camshaft of the lens barrel according to the fourth embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First Embodiment)
FIG. 1 is a schematic cross-sectional view of a lens barrel according to the first embodiment of the present invention. Although the followers of each lens holder are shown in FIG. 1 for convenience of explanation, in reality, the followers of each lens holder are provided so as to be out of phase in the rotation direction centered on the optical axis. , Not provided on the same cross section. Further, in FIG. 1, the upper side of the optical axis is a schematic cross-sectional view of the lens barrel at the wide position, and the lower side of the optical axis is a schematic cross-sectional view of the lens barrel at the tele position. In this embodiment, a lens barrel provided in a digital camera or the like as an example of an imaging device is taken as an example.

As shown in FIG. 1, the lens barrel of the present embodiment includes first to sixth optical units 11 to 16, cam cylinder 21 and fixed cylinder 22, and includes first to fifth optical units 11 to 15. A zoom operation is performed to change the shooting magnification by moving each in the optical axis direction. The cam cylinder 21 corresponds to an example of the cam member of the present invention.

The first optical unit 11 holds the first lens group 11a, and a plurality of first followers 11b are provided at substantially equal intervals in the circumferential direction on the inner peripheral portion of the end portion on the image plane side. The first follower 11b is engaged with a cam groove provided on the outer peripheral portion of the cam cylinder 21, and when the cam cylinder 21 rotates, the first follower 11b moves in the optical axis direction along the cam groove.

The second optical unit 12 holds the second lens group 12a, and a plurality of second followers 12b are provided on the outer peripheral portion of the end portion on the image plane side at substantially equal intervals in the circumferential direction. The second follower (cam pin) 12b is engaged with a cam groove provided in the inner peripheral portion of the cam cylinder 21, and when the cam cylinder 21 rotates, the second follower (cam pin) 12b moves in the optical axis direction along the cam groove.

The third optical unit 13 constitutes an aperture unit, and a third follower 13b is provided on the outer peripheral portion thereof. The third optical unit 13 is fitted and supported so as to be movable in the optical axis direction in a state where rotation is restricted with respect to the guide bars 23a and 23b. The third follower 13b is engaged with a cam groove provided in the inner peripheral portion of the cam cylinder 21, and when the cam cylinder 21 rotates, the third follower 13b moves in the optical axis direction along the cam groove.

The fourth optical unit 14 holds the third lens group 14a and is driven in the optical axis direction by the linear actuator 24. A plurality of fourth followers 14b are provided on the outer peripheral portion of the fourth optical unit 14 at substantially equal intervals in the circumferential direction, and the fourth followers 14b engage with cam grooves provided on the inner peripheral portion of the cam cylinder 21. ing. The details of the fourth optical unit 14 will be described later.

The fifth optical unit 15 holds the fourth lens group 15a and is fitted and supported so as to be movable in the optical axis direction in a state in which rotation is restricted with respect to the guide bars 23a and 23b. One fifth follower 15b is provided on the outer peripheral portion of the fifth optical unit 15. The linear actuator 24 corresponds to an example of the drive device of the present invention.

The sixth optical unit 16 holds the fifth lens group 16a constituting the focus lens, and moves in the optical axis direction by an actuator (not shown) to perform a focusing operation. An image sensor 25 such as a CCD sensor or a CMOS sensor is provided on the back side of the sixth optical unit 16. The image sensor 25 photoelectrically converts the subject image formed by passing through the first lens group 11a, the second lens group 12a, the third lens group 14a, the fourth lens group 15a, and the fifth lens group 16a into an electric signal. Is output to an image processing unit (not shown).

The linear actuator 24 is an ultrasonic motor that generates a driving force by generating ultrasonic vibration in the vibrator, and is a motor that drives the linear actuator in a straight line. Although the ultrasonic motor is small, it has a high output and almost no operating noise, so it is most suitable for driving a lens barrel. Although the detailed structure of the linear actuator 24 is omitted, when the vibrator is held in a pressurized contact state with the contact portion of the fourth optical unit 14, and the vibrator excites ultrasonic vibration, the fourth optical The unit 14 receives a driving force and moves.

Next, the zoom operation of the lens barrel will be described. In order to move the lens barrel from the upper wide position in FIG. 1 to the lower tele position, a linear actuator 24 arranged on the inner peripheral side of the cam cylinder 21 is driven to move the fourth optical unit 14 to the subject side ( Move in the direction of the optical axis toward the left side of the figure). Since the fourth follower 14b of the fourth optical unit 14 is engaged with the cam groove provided on the inner peripheral portion of the cam cylinder 21, the fourth optical unit 14 is caused by the cam action between the cam groove and the fourth follower 14b. Moves in the optical axis direction, and the cam cylinder 21 rotates.

When the cam cylinder 21 rotates, the first to third optical units 11 to 13 and the fifth optical unit 15 in which the followers 11b to 13b and the followers 15b are engaged with the corresponding cam grooves of the cam cylinder 21 correspond to each other. It moves toward the subject side by the cam action with the cam groove. By driving the linear actuator 24 to move the fourth optical unit 14 in the optical axis direction in this way, the other first to third optical units 11 to 13 and the fifth optical unit 15 move in the optical axis direction. The zoom operation is performed by moving to.

Next, with reference to FIG. 2, a reason for moving the fourth optical unit 14 in the optical axis direction by the linear actuator 24 when performing the zoom operation of the lens barrel will be described. FIG. 2 is a graph showing the relationship between the amount of movement of the first to fifth optical units 11 to 15 from the initial position and the position in the optical axis direction. In FIG. 2, the left side of the horizontal axis is the wide position, and the tele position approaches the right side. Further, the movement amount on the vertical axis is set to the initial position with the wide position as 0.

As shown in FIG. 2, the fourth optical unit 14 moves substantially linearly in one direction from the wide position to the tele position. By driving the fourth optical unit 14 that moves substantially linearly between the wide position and the tele position by the linear actuator 24, the cam cylinder 21 that cam engages with the fourth optical unit 14 is stably rotationally driven. Can be done.

For example, in the first optical unit 11, the optical unit 11 moves toward the subject side again after being transferred to the imaging surface side once. When the first optical unit 11 that follows the movement locus in which the movement direction changes is driven by the linear actuator 24 in this way, the cam inclination angle with respect to the optical axis of the cam groove of the cam cylinder 21 that cam engages with the first optical unit 11 is loose. A position is created. If the cam inclination angle is loose, the load for converting the force in the optical axis direction into the rotational force becomes large, and a stable rotational force of the cam cylinder 21 cannot be obtained. Therefore, in order to stably rotate the cam cylinder 21, it is preferable that the fourth optical unit 14 that follows a substantially linear movement locus in one direction is moved in the optical axis direction by the linear actuator 24.

As described above, in the present embodiment, a zoom operation is performed by driving a relatively small linear actuator 24 arranged on the inner peripheral side of the cam cylinder 21 to move the fourth optical unit 14 in the optical axis direction. It can be performed. Therefore, it is not necessary to lay out an actuator, a gear train of a reduction system, or the like on the radial outer side of the cam cylinder 21, and it is not necessary to provide as many motors as there are a plurality of lens groups. As a result, it is possible to reduce the size of the lens barrel without complicating the control of the motor that drives a plurality of lens groups in the optical axis direction.

(Second embodiment)
Next, the lens barrel according to the second embodiment of the present invention will be described with reference to FIGS. 3 to 6. FIG. 3 is a perspective view showing a main part of the lens barrel. FIG. 4 is a schematic cross-sectional view taken along the optical axis direction at the position of the camshaft 121 when the lens barrel shown in FIG. 3 is in the wide position. FIG. 5 is a schematic cross-sectional view taken along the optical axis direction at the position of the camshaft 121 when the lens barrel shown in FIG. 3 is in the tele position.

As shown in FIGS. 3 to 5, the lens barrel of the present embodiment includes a first optical unit 111 fixed to the storage case 110, and second to fifth optical units 112 to 115 movable in the optical axis direction. It includes a camshaft 121, guide bars 123a and 123b, and a storage case 110. The camshaft 121 and the guide bars 123a and 123b are arranged parallel to the optical axis, the camshaft 121 is rotatably supported by the storage case 110, and the guide bars 123a and 123b are fixed to the storage case 110. There is. The second optical unit 112 corresponds to an example of the first optical member of the present invention.

The first optical unit 111 holds the first lens group 111a and is fixed to the storage case 110. The first lens group 111a has two lenses provided orthogonal to each other, and a prism is provided between the two lenses. In the present embodiment, the first optical unit 111 is a fixed optical group, but it may be a mobile optical group. Further, the first lens group 111a does not necessarily have to include a prism, and may not have a prism, or may be provided in a lens group of another optical unit on the imaging surface side.

The second optical unit 112 holds the second lens group 112a, is fitted and held by the guide bar 123a, and is movably supported in the optical axis direction by being engaged and held by the guide bar 123b. ing. On the outer peripheral portion of the second optical unit 112, a first follower 112b that engages with the first cam portion 121a provided on the cam shaft 121 and a contact portion 112c with the linear actuator 124 are provided. The second optical unit 112 receives thrust in the optical axis direction from the linear actuator 124 when the contact portion 112c comes into contact with the linear actuator 124.

The third optical unit 113 holds the third lens group 113a, is fitted and held by the guide bar 123b, and is movably supported in the optical axis direction by being engaged and held by the guide bar 123a. ing. A second follower 113b that engages with the second cam portion 121b provided on the camshaft 121 is provided on the outer peripheral portion of the third optical unit 113.

The fourth optical unit 114 holds the fourth lens group 114a, is fitted and held by the guide bar 123b, and is movably supported in the optical axis direction by being engaged and held by the guide bar 123a. ing. A third follower 114b that engages with the third cam portion 121c provided on the cam shaft 121 is provided on the outer peripheral portion of the fourth optical unit 114.

The fifth optical unit 115 holds the fifth lens group 115a constituting the focus lens, is fitted and held by the guide bar 123b, and is engaged and held by the guide bar 123a in the optical axis direction. It is supported so that it can be moved.

The fifth optical unit 115 is independently driven in the optical axis direction by an actuator (not shown) to perform a focusing operation. An image sensor 125 is provided on the back side of the fifth optical unit 115.

The image sensor 125 is composed of a CCD sensor, a CMOS sensor, or the like, and is fixed to the storage case 110. The image sensor 125 photoelectrically converts the subject image formed by passing through the first lens group 111a, the second lens group 112a, the third lens group 113a, the fourth lens group 114a, and the fifth lens group 115a into an electric signal. Is output to an image processing unit (not shown).

The linear actuator 124 is an ultrasonic motor that generates a driving force by generating ultrasonic vibration in the vibrator, and is a motor that drives the linear actuator in a straight line. Although the ultrasonic motor is small, it has a high output and almost no operating noise, so it is most suitable for driving a lens barrel. Although the detailed structure of the linear actuator 124 is omitted, when the vibrator is held in a pressurized contact state with the contact portion 112c of the second optical unit 112 and the vibrator is excited by ultrasonic vibration, the second optical unit 112 is second. The optical unit 112 is driven.

Next, the operation of the lens barrel will be described. As described above, the second optical unit 112 receives thrust from the linear actuator 124 via the contact portion 112c and moves to a position corresponding to the zoom position. In the second optical unit 112, the first follower 112b is engaged with the first cam portion 121a of the cam shaft 121. Therefore, as the second optical unit 112 moves in the optical axis direction, the cam shaft 121 rotates due to the cam action between the first cam portion 121a and the first follower 112b.

In the camshaft 121, the second follower 113b of the third optical unit 113 is engaged with the second cam portion 121b, and the third follower 114b of the fourth optical unit 114 is engaged with the third cam portion 121c. Therefore, as the cam shaft 121 rotates, the cam action of the second cam portion 121b and the second follower 113b and the cam action of the third cam portion 121c and the third follower 114b cause the third optical unit 113 and the fourth. The optical unit 114 moves in the optical axis direction. As a result, the lens barrel is zoomed.

Next, with reference to FIG. 6, a reason for moving the second optical unit 112 in the optical axis direction by the linear actuator 124 when performing the zoom operation of the lens barrel will be described. FIG. 6 is a graph showing the relationship between the amount of movement of the second to fourth optical units 112 to 114 from the initial position and the position in the optical axis direction. In FIG. 6, the left side of the horizontal axis is the wide position, and the tele position approaches the right side. Further, the movement amount on the vertical axis is set to the initial position with the wide position as 0.

As shown in FIG. 6, of the second to fourth optical units 112 to 114, the second optical unit 112 moves substantially linearly from the wide position to the tele position. Therefore, by driving the second optical unit 112 in one direction with the linear actuator 124, the camshaft 121 engaged with the second optical unit can be stably rotationally driven.

For example, the third optical unit 113 moves from the wide position to the tele position by drawing a gentle curve toward the imaging surface. When the third optical unit 113 that follows such a movement locus is driven by the linear actuator 124, a position where the tilt angle of the second cam portion 121b of the cam shaft 121 that cam engages with the third optical unit 113 with respect to the optical axis is loose is formed. It ends up. If the inclination angle is loose, the load for converting the force in the optical axis direction into the rotational force becomes large, and the camshaft 121 does not rotate stably. Therefore, in order to stably rotate the camshaft 121, it is preferable to move the second optical unit 112, which has a moving direction in one direction and follows a substantially linear movement locus, in the optical axis direction by a linear actuator 124. ..

Further, among the cam portions 121a to 121c provided on the cam shaft 121, the inclination angle of the first cam portion 121a that engages with the second optical unit 112 driven by the linear actuator 124 with respect to the optical axis is the steepest. Is preferable. The reason is that the cam portion for rotating the cam shaft 121 requires a smaller thrust to rotate the cam shaft 121 when the inclination angle with respect to the optical axis is as steep as possible.

Further, when the inclination angle of the cam portions 121b and 121c of the cam shaft 121 with respect to the optical axis is as loose as possible, the rotational force of the cam shaft 121 for moving the third and fourth optical units 113 and 114 in the optical axis direction is reduced. It can be suppressed. The fact that the rotational force of the camshaft 121 can be reduced means that the thrust of the linear actuator 124 can be reduced. In order to realize such a relationship of the inclination angle of the cam portions 121a to 121c with respect to the optical axis, in the present embodiment, the second optical unit 112, which is the lens group most moving from the wide state to the tele state, is driven and the cam is driven. The diameter at which each cam of the shaft 121 is created is changed.

As described above, in the present embodiment, the zoom operation can be performed by moving the second optical unit 112 in the optical axis direction by a relatively small linear actuator 124 arranged in the storage case 110. Therefore, it is not necessary to lay out an actuator, a gear train of a reduction system, or the like on the radial outer side of the cam cylinder, and it is not necessary to provide as many motors as there are a plurality of lens groups. As a result, it is possible to reduce the size of the lens barrel without complicating the control of the motor that drives a plurality of lens groups in the optical axis direction.

Further, in the present embodiment, since the camshaft 121, the guide bars 123a, 123b and the linear actuator 124 are arranged in one direction orthogonal to the optical axis (arrow X direction in FIG. 3), the lens barrel can be made thinner. Can be planned.

Further, in the linear actuator 124 used in the present embodiment, the vibrator is held in contact with the contact portion 112c of the second optical unit 112 in a pressurized state, so that the guide bar 123 of the second optical unit 112 is held. It acts as an offset against. Therefore, the second optical unit 112 can realize smooth and stable movement.

Further, in the present embodiment, the second to fourth optical units 112 to 114 are moved in the optical axis direction by the rotation of the shaft-shaped camshaft 121 arranged in the storage case 110. For this reason, the degree of freedom in layout is increased as compared with the case of using a cam cylinder, and it is possible to form a lens barrel that is not tubular.

(Third Embodiment)
Next, the lens barrel according to the third embodiment of the present invention will be described with reference to FIGS. 6 to 11. FIG. 7 is a perspective view showing a main part of the lens barrel. FIG. 8 is a perspective view seen from the back side of FIG. 7. FIG. 9 is a schematic cross-sectional view taken along the optical axis direction at the position of the camshaft 121 when the lens barrel shown in FIG. 7 is in the wide position. FIG. 10 is a schematic cross-sectional view taken along the optical axis direction at the position of the camshaft 121 when the lens barrel shown in FIG. 7 is in the tele position. FIG. 11 is a schematic view when the cam portion of the cam shaft 121 is developed with a predetermined diameter.

As shown in FIGS. 7 to 11, the lens barrel of the present embodiment includes a first optical unit 111 fixed to the storage case 110 and second to fifth optical units 112 to 115 movable in the optical axis direction. , Camshaft 121, urging cam 122, guide bars 123a, 123b. The camshaft 121, the urging cam 122, and the guide bars 123a and 123b are arranged parallel to the optical axis, the camshaft 121 is rotatably supported by the storage case 110, and the guide bars 123a and 123b are the storage cases. It is fixed at 110. The second optical unit 112 corresponds to an example of the first optical member of the present invention, and the third optical unit 113 corresponds to an example of the second optical member of the present invention.

The first optical unit 111 holds the first lens group 111a and is fixed to the storage case 110. The first lens group 111a has two lenses provided orthogonal to each other, and a prism is provided between the two lenses. In the present embodiment, the first optical unit 111 is a fixed optical group, but it may be a mobile optical group. Further, the first lens group 111a does not necessarily include a prism, and the prism may be provided in the lens group of another optical unit on the imaging surface side.

The second optical unit 112 holds the second lens group 112a, is fitted and held by the guide bar 123a, and is movably supported in the optical axis direction by being engaged and held by the guide bar 123b. ing. On the outer peripheral portion of the second optical unit 112, a first follower 112b that engages with the first cam portion 121a provided on the cam shaft 121 and a contact portion 112c with the linear actuator 124 are provided. The second optical unit 112 receives thrust in the optical axis direction from the linear actuator 124 when the contact portion 112c comes into contact with the linear actuator 124. The first cam portion 121a corresponds to an example of the first engaging portion of the present invention, and the second cam portion 121b corresponds to an example of the second engaging portion of the present invention.

The third optical unit 113 holds the third lens group 113a, is fitted and held by the guide bar 123b, and is movably supported in the optical axis direction by being engaged and held by the guide bar 123a. ing. A second follower 113b that engages with the second cam portion 121b provided on the camshaft 121 is provided on the outer peripheral portion of the third optical unit 113.

The third optical unit 113 is urged by the first spring 126 in a direction in which the second optical unit 112 and the third optical unit 113 are separated from each other. Specifically, the third optical unit 113 is urged downward in FIG. 7. Therefore, it is possible to maintain a state of constant contact with the second cam portion 121b of the cam shaft 121, and as the cam shaft 121 rotates, the third optical unit 113 illuminates following the surface of the second cam portion 121b. It can be moved in the axial direction.

The fourth optical unit 114 holds the fourth lens group 114a, is fitted and held by the guide bar 123b, and is movably supported in the optical axis direction by being engaged and held by the guide bar 123a. ing. A third follower 114b that engages with the third cam portion 121c provided on the cam shaft 121 is provided on the outer peripheral portion of the fourth optical unit 114.

The fourth optical unit 114 is held so that the third follower 114b is sandwiched between the third cam portion 121c and the urging cam 122 described later. By doing so, the state in which the third follower 114b is always in contact with the third cam portion 121c can be maintained, and when the cam shaft 121 rotates, it follows the surface of the third cam portion 121c and is oriented in the optical axis direction. It is movable.

The fifth optical unit 115 holds the fifth lens group 115a constituting the focus lens, is fitted and held by the guide bar 123b, and is engaged and held by the guide bar 123a in the optical axis direction. It is supported so that it can be moved. The fifth optical unit 115 is independently driven in the optical axis direction by an actuator to perform a focusing operation. An image sensor 125 is provided on the back side of the fifth optical unit 115.

The camshaft 121 has a shaft shape with a step, and a first cam portion 121a, a second cam portion 121b, and a third cam portion 121c are provided on the outer peripheral portion thereof. The first cam portion 121a is formed in a groove shape, and is engaged so that the first follower 112b provided in the second optical unit 112 is supported on two surfaces so as to be sandwiched between the grooves. Further, the second cam portion 121b is provided on a convex portion having a diameter different from the diameter provided with the first cam portion 121a, and a cam surface is formed on a side surface in the direction in which the first cam portion 121a is located. As described above, the third optical unit 113 is urged downward in FIG. 11 so that it can move in accordance with the second cam portion 121b. Further, the third cam portion 121c has substantially the same diameter as the diameter provided with the second cam portion 121b, and is formed on a surface in a direction opposite to that of the second cam portion 121b.

The urging cam 122 is arranged coaxially with the cam shaft 121 and has a second spring 127 inside. The camshaft 121 and the urging cam 122 can be moved to each other in the rotation axis direction by key fitting, and the rotation directions are integrally rotated. Further, the camshaft 121 and the urging cam 122 are urged in a direction approaching each other by the second spring 127. At the upper end of the urging cam 122, a third B cam 122a having a locus similar to that of the third cam portion 121c of the cam shaft 121 is provided. The third follower 114b of the fourth optical unit 114 is engaged so as to be sandwiched between the third B cam 122a and the third cam portion 121c. Due to the urging of the second spring 127, the third follower 114b is constantly pressed against the third cam portion 121c and is held without rattling.

The image sensor 125 is composed of a CCD sensor, a CMOS sensor, or the like, and is fixed to the storage case 110. The image sensor 125 photoelectrically converts the subject image formed by passing through the first lens group 111a, the second lens group 112a, the third lens group 113a, the fourth lens group 114a, and the fifth lens group 115a into an electric signal. Is output to an image processing unit (not shown).

Next, the shape and molding method of the camshaft 121 will be described in detail with reference to FIGS. 11 to 13. FIG. 11 is a schematic view showing a state in which the first to third cam portions 121a to 121c are deployed with a predetermined diameter. FIG. 12 schematically shows a die-cutting method when molding a camshaft with a mold, and FIG. 13 schematically shows a die-cutting direction of the molding die by deploying the camshaft with a predetermined diameter. It is a thing.

Since the camshaft 121 and the second to fourth optical units 112 to 114 move in conjunction with each other, the loci of the cam portions 121a to 121c shown in FIG. 11 coincide with the lens movement loci at each zoom position.

As is clear from FIG. 11, the first cam portion 121a is formed linearly at a predetermined inclination angle α, and the second cam portion 121b and the third cam portion 121c are formed non-linearly. is there. At this time, when the inclination angle of the maximum inclined portion in the second cam portion 121b is β, the relationship of α ≧ β is established.

12 and 13 show how the upper and lower molds 131 and 132 are pulled out when molding the camshaft 121 set in this way to release the shape from the molded product. When molding the camshaft 121, the first cam portion 121a and the second cam portion 121b are rotationally punched out at an inclination angle α by the integral piece 131 capable of molding (in FIG. 13, the second cam portion 121b of the mold 131). The ridges that form 131-1 and 131-2 move). The third cam portion 121c can be formed by sliding the third cam portion 121c downward in FIG. 12 with the mold 132. In this way, while the first cam portion 121a is formed in a groove shape, both the first cam portion 121a and the second cam portion 121b can be formed without a mold dividing line inserted in the middle.

For example, when α <β, if the rotation is pulled out at an inclination angle of α, the mold cannot be removed so as to avoid the surface of the second cam portion 121b, resulting in an undercut. In the actual molding, as shown in FIG. 12, the mold structure is such that the mold 131 is rotated and pulled out upward. Further, the second cam portion 121a having a groove shape needs to have a straight groove of α degree so as not to be undercut, but in the present embodiment, the second cam portion 121b and the third cam portion 121c are The cam portion has a surface shape. As a result, the locus of the cam is non-linear and can be molded without forming an undercut shape.

Further, assuming that the first to third cam portions 121a to 121c provided on the cam shaft 121 are within about 120 °, the cam can be molded by the integrated piece 131 in a die-cutting structure from the circumferential direction. There is no mold step on the way. However, in the present embodiment, even if the rotation angle is as large as 120 ° or more, it can be molded by the integrated piece. The camshaft 121 is formed to have a relatively small diameter, and if the camshaft is designed to have a sufficient length so that the optical unit can move with high accuracy, the rotation angle becomes large, so this configuration is effective. is there. If a mold step is generated in the middle of the cam, it leads to shaking of each optical unit that moves according to the cam, which is not preferable because the performance is deteriorated and the image is not visible.

Further, in the wide state of the second cam portion 121b, a dropout wall 121d as an example of the fallout prevention portion of the present invention is provided at a position further advanced in the direction opposite to the tele direction from the position where the second follower 113b is engaged. .. As a result, it is possible to prevent the camshaft 121 from being inadvertently rotated due to an impact applied in the wide state and the second follower 113b from falling off.

Further, the third cam portion 121c is formed by pulling out the mold 132 downward as described above. Therefore, in the present embodiment, the first to third cam portions 121a to 121c are formed in a range that does not exceed approximately 360 °. Specifically, it is assumed that the camshaft 121 rotates 320 ° in the wide position-tele position.

Next, the operation of the lens barrel will be described. As described above, the second optical unit 112 receives thrust from the linear actuator 124 via the contact portion 112c and moves to a position corresponding to the zoom position. In the second optical unit 112, the first follower 112b is engaged with the first cam portion 121a of the cam shaft 121. Therefore, as the second optical unit 112 moves in the optical axis direction, the cam shaft 121 rotates due to the cam action between the first cam portion 121a and the first follower 112b.

In the camshaft 121, the second follower 113b of the third optical unit 113 is engaged with the second cam portion 121b, and the third follower 114b of the fourth optical unit 114 is engaged with the third cam portion 121c. Therefore, as the cam shaft 121 rotates, the cam action of the second cam portion 121b and the second follower 113b and the cam action of the third cam portion 121c and the third follower 114b cause the third optical unit 113 and the fourth. The optical unit 114 moves in the optical axis direction. As a result, the lens barrel is zoomed.

Next, the reason for moving the second optical unit 112 in the optical axis direction by the linear actuator 124 when performing the zoom operation of the lens barrel of the present embodiment by diverting FIG. 6 used in the second embodiment. Will be described. As described above, FIG. 6 is a graph showing the relationship between the amount of movement of the second to fourth optical units 112 to 114 from the initial position and the position in the optical axis direction. In FIG. 6, the left side of the horizontal axis is the wide position, and the tele position approaches the right side. Further, the movement amount on the vertical axis is set to the initial position with the wide position as 0.

As shown in FIG. 6, of the second to fourth optical units 112 to 114, the second optical unit 112 moves substantially linearly from the wide position to the tele position. Therefore, by driving the second optical unit 112 in one direction with the linear actuator 124, the camshaft 121 that engages with the second optical unit 112 can be stably rotationally driven.

For example, the third optical unit 113 moves from the wide position to the tele position by drawing a gentle curve toward the imaging surface. When the third optical unit 113 that follows such a movement locus is driven by the linear actuator 124, a position where the tilt angle of the second cam portion 121b of the cam shaft 121 that cam engages with the third optical unit 113 with respect to the optical axis is loose is formed. It ends up. Therefore, in order to stably rotate the camshaft 121, it is preferable that the second optical unit 112, which follows a substantially linear movement locus in one direction, is moved in the optical axis direction by the linear actuator 124.

Further, among the first to third cam portions 121a to 121c provided on the cam shaft 121, the optical unit driven by the linear actuator 124 is the optical unit in which the inclination angle of the cam portion with respect to the optical axis is the steepest. preferable. The reason is that the cam portion for rotating the cam shaft 121 requires a smaller thrust to rotate the cam shaft 121 when the inclination angle with respect to the optical axis is as steep as possible.

Further, when the inclination angle of the cam portions 121b and 121c of the cam shaft 121 with respect to the optical axis is as loose as possible, the rotational force of the cam shaft 121 for moving the third and fourth optical units 113 and 114 in the optical axis direction is reduced. It can be suppressed. The fact that the rotational force of the camshaft 121 can be reduced means that the thrust of the linear actuator 124 can be reduced. In order to realize such a relationship of the inclination angle of the cam portions 121a to 121c with respect to the optical axis, in the present embodiment, the diameter of the cam shaft 121 is changed in the optical axis direction.

As described above, in the present embodiment, the camshaft 121 having a small diameter is arranged outside the optical units 112 to 114 to realize thinning and miniaturization in which a plurality of optical units 112 to 114 can be moved. It is a lens barrel. Even if the angle range of the cam portions 121a to 121c formed on the cam shaft 121 is relatively large, the cam shape is formed so that it can be formed by an integral mold piece. As a result, it is assumed that there is no mold split step in the middle of the cam.

In the present embodiment, when the cam shaft 121 is molded, the first cam portion 121a and the second cam portion 121b are formed by rotationally pulling out the first cam portion 121a and the second cam portion 121b with an integrated piece, and the third cam portion 121c is formed. Is not a non-rotating configuration. However, it may have a cam portion that allows the third cam portion 121c to be rotated out, and further, it has a fourth cam portion, and the third cam portion and the fourth cam portion are rotated by an integrated piece. It does not matter if it is configured to be pulled out.

Further, in the present embodiment, an ultrasonic type linear actuator 124 is used to rotate the camshaft 121, but the present invention is not limited to this, and the camshaft 121 does not have to be an ultrasonic type and is linear. It does not have to have an output. For example, a stepping motor may rotate the camshaft 121 directly or via a plurality of gears. At that time, the second optical unit 112, the third optical unit 113, and the fourth optical unit 114 move with the rotation of the camshaft 121.

(Fourth Embodiment)
Next, the lens barrel according to the fourth embodiment of the present invention will be described with reference to FIG. FIG. 14 is a schematic cross-sectional view taken along the optical axis direction at the position of the camshaft 221 of the lens barrel. In this embodiment, the parts that overlap with those of the third embodiment are designated by the same reference numerals, and only the differences will be described.

As shown in FIG. 14, the lens barrel of the present embodiment includes a first optical unit 111 fixed to a storage case 110, second to fourth optical units 212 to 214 movable in the optical axis direction, and a fifth. The optical unit 115 is provided. The lens barrel includes a camshaft 221 and an urging cam 222, and guide bars 123a and 123b. The cam shaft 221 and the urging cam 222, and the guide bars 123a and 123b are arranged in parallel with the optical axis, respectively, and the cam shaft 221 and the urging cam 222 are rotatably supported by the storage case 110.

The first optical unit 111 is the same as that of the third embodiment. The second optical unit 212 holds the second lens group 212a and is supported so as to be movable in the optical axis direction, as in the third embodiment. A first follower 212b that engages with the first cam portion 221a provided on the camshaft 221 is provided on the outer peripheral portion of the second optical unit 212. The first follower 212b has a different shape from the first follower 112b of the third embodiment, and has a cylindrical wedge shape having a larger diameter toward the outside.

The third optical unit 213 holds the third lens group 213a and is supported so as to be movable in the optical axis direction, as in the third embodiment. A second follower 213b that engages with the second cam portion 221b provided on the camshaft 221 is provided on the outer peripheral portion of the third optical unit 213. The second follower 213b has a cylindrical wedge shape in which the diameter becomes larger toward the outside like the first follower 212b. Further, the second follower 213b is urged downward in FIG. 14 as in the third embodiment, and can always maintain a state of being in contact with the cam portion 221b of the camshaft 221. it can.

The fourth optical unit 214 holds the fourth lens group 214a and is supported so as to be movable in the optical axis direction, as in the third embodiment. A third follower 214b that engages with the third cam portion 221c provided on the camshaft 221 is provided on the outer peripheral portion of the fourth optical unit 214. The third follower 214b has a cylindrical wedge shape in which the diameter becomes larger toward the outside like the first follower 212b.

The third follower 214b of the fourth optical unit 214 is held so as to be sandwiched between the third cam portion 221c and the urging cam 222. By doing so, the state in which the third follower 214b is always in contact with the third cam portion 221c can be maintained, and when the cam shaft 221 rotates, it follows the surface of the third cam portion 221c and moves in the optical axis direction. It is movable. The fifth optical unit 115 is a focus lens group similar to the third embodiment.

Similar to the third embodiment, the camshaft 221 has a stepped shaft shape, and the first cam portion 221a, the second cam portion 221b, and the third cam portion 221c are provided on the outer peripheral portion thereof. ing. The first cam portion 221a is formed in a groove shape, and is engaged so that the first follower 212b provided on the second optical unit 212 is supported on two surfaces so as to be sandwiched between the grooves of the first cam portion 221a. doing.

As described above, the first follower 212b has a cylindrical wedge shape, and the groove shape of the first cam portion 221a with which the first follower 212b engages also has a wedge shape whose diameter becomes smaller toward the outer peripheral portion. It is formed like this. Further, the second cam portion 221b is provided on the cam shaft 221 different from the diameter provided with the first cam portion 221a, and the cam surface is formed in the direction in which the first cam portion 221a is located. The second cam portion 221b is formed by a wedge surface corresponding to the wedge shape of the second follower 213b that engages with the second cam portion 221b.

Further, the third cam portion 221c has substantially the same diameter as the diameter provided with the second cam portion 221b, and is formed on a surface of the cam shaft 221 in a direction opposite to that of the second cam portion 221b. Similar to the second cam portion 221b, the third cam portion 221c is formed by a wedge surface corresponding to the wedge shape of the engaging third follower 214b.

The urging cam 222 is arranged coaxially with the cam shaft 221 and has a second spring 127 inside. A third B cam 222a having a locus similar to that of the third cam portion 221c of the cam shaft 221 is provided at the upper end of the urging cam 222, and the third B cam 222a has a wedge surface corresponding to the wedge shape of the third follower 214b. It was formed in.

The deployment locus of the first to third cam portions 221a to 221c provided on the camshaft 221 at a predetermined diameter is the same as that of the camshaft 121 of the third embodiment (FIG. 11). That is, as described above, the first cam portion 221a and the second cam portion 221b are formed while being rotated out by an integral mold piece. The difference between the camshaft 221 and the camshaft 121 of the third embodiment is that the cross-sectional shape when viewed from the direction perpendicular to the movement locus is wedge-shaped. This wedge-shaped camshaft 221 is not molded because it is undercut when punched from the radial direction. As shown in FIGS. 12 and 13, it can be created by pulling out the first cam portion 221a and pulling out the second cam portion 221b and the third cam portion 221c made of surfaces from the direction of the rotation axis. As a result, it is possible to mold without undercutting.

By doing so, if the first cam portion 221a and the first follower 212b are inserted from the end portions, there is no possibility that the first follower 212b will come off from the first cam portion 221a during the rotation of the camshaft 221. .. Similarly, the second follower 213b and the third follower 214b can be prevented from being easily detached from the second cam portion 221b and the third cam portion 221c. As a result, even if the camshaft is deformed by applying an external force such as dropping or impact to the lens barrel, the first to third followers 212b, 213b, and 214b are the first to third cam portions 221a to. It will be hard to come off from 221c.

The camshaft 221 of the present embodiment has a shape in which the groove of the cam portion is wider on the inner side (inner diameter direction) than on the inlet (outer diameter direction) because the mold is formed by rotary punching. A wedge-shaped groove can be realized. In the present embodiment, the cams are provided so that the cross section of each of the first to third cam portions has a wedge shape, but only a part of the cam portions may have a wedge shape.

The configuration of the present invention is not limited to those exemplified in each of the above embodiments, and the material, shape, dimensions, form, number, arrangement location, etc. are appropriately changed as long as the gist of the present invention is not deviated. It is possible.

110 Storage cases 11, 111 1st optical unit 12, 112 2nd optical unit 13, 113 3rd optical unit 14, 114 4th optical unit 15, 115 5th optical unit 16 6th optical unit 21 Cam cylinder 22 Fixed cylinder 23a , 23b Guide bar 24, 124 Linear actuator 25, 125 Image sensor

Claims (15)

A first optical member that moves in the optical axis direction of the lens barrel,
The second optical member that moves in the optical axis direction and
A cam member that is cam-engaged with each of the first optical member and the second optical member, is arranged parallel to the optical axis, and is rotatably held.
A linear actuator for driving the first optical member is provided.
The cam member is rotated by the cam action of the cam member and the first optical member that moves in the optical axis direction by the linear actuator.
The second optical member moves in the optical axis direction due to the cam action between the second optical member and the cam member due to the rotation of the cam member.
A lens barrel characterized in that the cam member is arranged on the outer peripheral portion of the first optical member. The cam member is formed with a first cam groove with which a cam pin constituting the first optical member is engaged and a second cam groove with which a cam pin constituting the second optical member is engaged. ,
The lens barrel according to claim 1, wherein the cam tilt angle of the first cam groove is larger than the cam tilt angle of the second cam groove. A guide bar for guiding the first optical member and the second optical member in the optical axis direction is provided.
The lens barrel according to claim 1 or 2, wherein the cam member, the guide bar, and the linear actuator are arranged in one direction orthogonal to the optical axis. Any one of claims 1 to 3, wherein when the first optical member moves from the wide position to the tele position, the movement direction of the first optical member with respect to the cam member is only one direction. The lens barrel according to item 1. An imaging device including the lens barrel according to any one of claims 1 to 4. Cams axis, the lens barrel according to any one of claims 1 to 4 and the linear actuator about said optical axis and being arranged in the opposite position. A first optical member that moves in the optical axis direction of the lens barrel,
The second optical member that moves in the optical axis direction and
The combined each cam engagement of the first optical member and the second optical member, arranged parallel to the optical axis, and Luca arm member is rotatably held,
An actuator for driving the first optical member is provided.
The cam member rotates due to the cam action of the cam member and the first optical member that moves in the optical axis direction by the actuator.
The second optical member moves in the optical axis direction due to the cam action between the second optical member and the cam member due to the rotation of the cam member.
The cam member comprises a first cam engaging member formed by itself and to which a second cam engaging member constituting the first optical member engages, and a second cam member forming the second optical member. It has a third cam engaging member with which the cam engaging member of 4 engages.
A lens barrel characterized in that the cam tilt angle of the first cam engaging member is larger than the cam tilt angle of the third cam engaging member. Each of the first cam engaging member and the third cam engaging member includes a cam groove, and each of the second cam engaging member and the fourth cam engaging member includes a cam pin. The lens barrel according to claim 7. By moving at least the first optical member and the second optical member in the optical axis direction of the lens barrel, the photographing magnification is changed from the wide position to the tele position.
The lens barrel according to claim 7 or 8, wherein the first cam engaging member has a first cam groove, and the third cam engaging member has a second cam groove. .. The first cam groove has a groove shape in which its two surfaces engage with the first optical member, and the second cam groove is on the side where the first cam groove is provided. The lens barrel according to claim 9, further comprising a convex portion provided with a surface that engages with the optical member of 2. The lens barrel according to claim 10, wherein the second cam groove is provided with a fall-out preventing portion for preventing the second cam groove from being disengaged from the second optical member. Claims 9 to 11 are characterized in that the diameter of the portion of the cam member where the first cam groove is formed and the diameter of the portion of the cam member where the second cam groove is formed are different from each other. The lens barrel according to any one of the above. The invention according to any one of claims 9 to 12, wherein when the cam member is molded, the first cam groove and the second cam groove are formed by one rotary punching piece. Lens barrel. The invention according to any one of claims 9 to 13, wherein the cam member is arranged on the outer peripheral portion of the first optical member and the second optical member and has a shaft shape with a step. Lens barrel. 9. The cam groove of either the first cam groove or the second cam groove has a wedge shape in which the groove width becomes wider as it is closer to the center of rotation of the cam member. The lens barrel according to any one of items 14 to 14.

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