WO2008007653A1

WO2008007653A1 - Drive regulation structure of piezoelectric actuator and lens drive equipped with the same

Info

Publication number: WO2008007653A1
Application number: PCT/JP2007/063701
Authority: WO
Inventors: Katsuyuki Ishiguro; Yasuaki Kameyama
Original assignee: Alps Electric Co., Ltd.
Priority date: 2006-07-14
Filing date: 2007-07-09
Publication date: 2008-01-17
Also published as: KR20090027765A; JPWO2008007653A1; CN101490945A

Abstract

A drive regulation structure of a piezoelectric actuator for efficiently regulating parallel translation of the rotating shaft of the piezoelectric actuator without causing any damage on the peripheral member or abrasion thereof. The drive regulation structure of a piezoelectric actuator for rotating the rotating shaft by controlling application of a voltage to a piezoelectric element and translating the rotating shaft to the axial direction is characterized by comprising a stopper (7c) projecting in the direction intersecting the axial direction of a rotating shaft (7b) perpendicularly and rotating integrally with the rotating shaft (7b), and regulation pieces (16a, 16b) abutting against the stopper (7c) when the rotating shaft (7b) translates up to a predetermined position and regulating rotation of the rotating shaft (7b).

Description

Specification

Piezoelectric actuator drive restricting structure and lens drive device having the same

TECHNICAL FIELD [0001] The present invention relates to a drive restricting structure of a piezoelectric actuator and a lens driving device including the same, and in particular, driving of a piezoelectric actuator that rotates a rotating shaft and translates in the axial direction by controlling voltage application to a piezoelectric element. The present invention relates to a regulation structure and a lens driving device including the regulation structure.

Background art

Conventionally, piezoelectric actuators have been widely used for precision control of semiconductor manufacturing and industrial equipment. In recent years, the application to digital cameras and camera-equipped mobile phones has been rapidly expanding. For example, it is used in various fields such as the camera shake correction function in digital cameras and the drive control of auto focus lenses. And

As such a piezoelectric actuator, a rotating shaft having a thread formed on the outer peripheral surface, a nut having a thread corresponding to the thread of the rotating shaft formed on the inner peripheral surface, and the rotating shaft and the nut The housing is equipped with a housing to which a plurality of piezoelectric elements are affixed, and the piezoelectric element is expanded and contracted by switching the voltage applied to the piezoelectric element, rotating the rotating shaft and simultaneously rotating it in the axial direction. There has been proposed a piezoelectric actuator that translates in parallel (see Patent Document 1, for example).

Patent Document 1: US Pat. No. 6,940,209

Disclosure of the invention

[0004] In the piezoelectric actuator as described above, a propulsive force is generated on the rotating shaft by sliding contact between the threads along with expansion and contraction of the piezoelectric element. It is necessary to give a certain load to the. In addition, it is necessary to regulate the parallel movement of the rotating shaft at a fixed position. Here, when such a linear movement of the rotating shaft is restricted by a contact member orthogonal to the moving direction, the regulating force of the contact member with respect to the rotating shaft becomes the load of the rotating shaft as it is and the propulsive force is increasingly increased. It will increase. As a result, the contact member is damaged, or the rotating shaft bites into the contact member and the stop state force cannot escape. There is a problem that.

[0005] The present invention has been made in view of the serious problem, and the piezoelectric actuator capable of efficiently regulating the parallel movement of the rotating shaft of the piezoelectric actuator without damaging or wearing the peripheral members. It is an object of the present invention to provide a drive regulating structure and a lens driving device using the same.

[0006] A drive restriction structure for a piezoelectric actuator according to the present invention is a drive restriction structure for a piezoelectric actuator that controls voltage application to a piezoelectric element to rotate a rotating shaft and translate it in the axial direction. A protruding member that protrudes in a direction perpendicular to the axial direction of the rotating shaft and rotates integrally with the rotating shaft, and contacts the protruding member when the rotating shaft moves in parallel to a certain position, thereby restricting the rotation of the rotating shaft. And a restricting member.

[0007] According to the drive restricting structure of the piezoelectric actuator, since the rotation of the rotating shaft is restricted by the restricting member when the rotating shaft moves in parallel to a certain position, the contact member orthogonal to the moving direction of the rotating shaft. Therefore, the rotation of the rotating shaft can be controlled with a small force compared to the case where the propulsive force generated by the rotating shaft is received, so that the parallel movement of the rotating shaft of the piezoelectric actuator can be efficiently performed without damaging or wearing the surrounding members. It becomes possible to regulate.

[0008] In the drive restricting structure of the piezoelectric actuator, the two restricting members spaced apart from each other may be disposed along the axial direction of the rotating shaft. In this case, the translation of the rotary shaft is allowed within the range of the interval provided between the two regulating members, and the translational movement of the rotary shaft in both axial directions is regulated by the two regulating members. It becomes possible

[0009] In the drive restricting structure of the piezoelectric actuator, the restricting member may be formed integrally with a holding member that holds the piezoelectric actuator. In this case, it is not necessary to provide a configuration for holding the regulating member, so that the number of parts can be reduced and the manufacturing cost of the structure can be reduced.

[0010] It should be noted that the piezoelectric actuator drive regulating structure according to any one of claims 1 to 3 may be applied to a lens driving device. By applying these piezoelectric actuator drive restricting structures to the lens driving device, the lens driving device is also described above. An effect can be obtained.

[0011] According to the present invention, it is possible to efficiently regulate the parallel movement of the rotating shaft of the piezoelectric actuator without damaging or wearing the peripheral members.

Brief Description of Drawings

FIG. 1 is an exploded perspective view of a lens driving device to which a drive restricting structure for a piezoelectric actuator according to an embodiment of the present invention is applied.

FIG. 2 is an external perspective view when the lens driving device shown in FIG. 1 is assembled.

FIG. 3 is a perspective view showing the internal configuration of the lens driving device according to the embodiment.

FIG. 4 is a top view showing an internal configuration of the lens driving device according to the embodiment.

[Fig.5] Cross section along solid line A-A shown in Fig.4

[Fig. 6] Cross section along line BB in Fig. 4

FIG. 7 is an exploded view for explaining a configuration of a motor included in the lens driving device according to the embodiment.

FIG. 8 is a perspective view for explaining a configuration of a stagger plate included in the lens driving device according to the embodiment.

FIG. 9 is a perspective view for explaining the relationship between the stopper and the stopper plate included in the lens driving device according to the embodiment.

FIG. 10 is a perspective view for explaining the relationship between the stopper and the stopper plate of the lens driving device according to the embodiment.

FIG. 11 is a schematic diagram for explaining a configuration of a lens holder included in the lens driving device according to the embodiment.

FIG. 12 is a schematic diagram for explaining a configuration of a first lens held by a lens holder included in the lens driving device according to the embodiment.

FIG. 13 is a schematic diagram for explaining a configuration of a second lens held by a lens holder included in the lens driving device according to the embodiment.

FIG. 14 is a schematic diagram for explaining a configuration of a third lens held by a lens holder included in the lens driving device according to the embodiment.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is an exploded perspective view of a lens driving device to which a drive restricting structure for a piezoelectric actuator according to an embodiment of the present invention is applied. FIG. 2 is an external perspective view when the lens driving device shown in FIG. 1 is assembled.

As shown in FIG. 1, a lens driving device 1 according to the present embodiment includes a substrate 3 on which an image sensor 2 is mounted, a base 5 on which an IR cut filter 4 is mounted, a lens holder 6 and A case 8 to which a motor 7 or the like as a piezoelectric actuator is attached and a shield case 9 for housing the case 8 are configured.

The substrate 3 is provided in a square shape with reference to the upper side force shown in FIG. The image sensor 2 is provided in a rectangular shape when viewed from the upper side force shown in FIG. 1, and is mounted on the substrate 3 such that its long side and short side are parallel to the side of the substrate 3. In FIG. 1, the image sensor 2 is mounted on the substrate 3 so that the long side 2a and the short side 2b of the image sensor 2 are parallel to the sides 3a and 3b of the substrate 3. Show me!

The base 5 is made of an insulating resin material and is provided in a square shape corresponding to the substrate 3. Near the center of the base 5, a rectangular opening 5a is formed at a position corresponding to the image sensor 2, and a circular recess 5b is formed around the opening 5a. The IR cut filter 4 is mounted in a position corresponding to the opening 5a in the recess 5b. In addition, at the four corners of the base 5, recesses 5c are formed to accommodate mounting legs 9b of a shield case 9 described later.

[0017] The case 8 is formed of an insulating resin material, and a circular opening 8a is formed at the center thereof. Around the opening 8a, a cam receiving portion 8b having an annular shape on which a cam gear 13 to be described later is placed is erected. The side surface 8c of the case 8 is formed with a notch 8d to which a hall element 10 for detecting a magnet position of a cam gear 13 (to be described later) is fixed, and a shaft that passes through a hole 12d of a link member 12 (to be described later). 8e is erected. On the side surfaces 8f and 8g adjacent to the side surface 8c, a pair of protrusions 8h are formed to be engaged with a hole 9c of a shield case 9 described later. A groove portion 8i that accommodates a rack portion 11a of a rack plate 11 to be described later is formed at a position inside the side surface 8 beam device. One end of the side surface ¾ of the case 8 has one end of a biasing spring that biases a rack plate 11 described later in the direction of the side surface 8c. A wall 8k that restricts the movement is formed.

The lens holder 6, the motor 7, the hall element 10, the rack plate 11, and the link member 12 are attached to the case 8 having such a configuration. In this case, the lens holder 6 is attached to the case 8 via the cam gear 13, and the motor 7 is attached to the case 8 via the motor holder 14.

[0019] The lens holder 6 is made of an insulating resin material, and holds a plurality of lenses 19 to 21 described later in a space formed inside. The lens holder 6 is provided in a shape along the shape of the plurality of lenses to be held, and has a small diameter portion 6a and a large diameter portion 6b. The large-diameter portion 6b is formed with a housing portion 6c that houses a part of the motor 7 along the side surface 8g of the case 8. The detailed configuration of the lens holder 6 and the configuration of the lens held in the lens holder 6 will be described later.

[0020] The small diameter portion 6a has an opening 6d functioning as a light entrance on the upper surface thereof. In addition, a pair of protruding pieces 6e protruding to the side of the lens driving device 1 are formed. The protruding piece 6e is accommodated in a groove portion 17c formed in a rotation restricting member 17 described later, and assists the vertical movement of the lens holder 6 shown in FIG. The large-diameter portion 6b is formed with a plurality of protruding pieces 6f that protrude to the side of the lens driving device 1. The protruding piece 6f has an inclined surface 6g that slides on the upper surface of the cam gear 13 on the lower surface. Further, a locking piece 6h for locking a lower end portion of a biasing spring 17 described later is formed on the upper surface of the large diameter portion 6b.

[0021] The cam gear 13 is formed of an insulating resin material and has an annular shape. The cam gear 13 has approximately the same diameter as the cam receiving portion 8b, a cam portion 13a placed on the cam receiving portion 8b, and a hole attached to the case 8 disposed on the outer peripheral side of the cam portion 13a. It has the magnet part 13b which opposes the element 10. FIG. A plurality of bottom surface portions 13c, inclined surfaces 13d, and top surface portions 13e are formed on the upper surface of the cam portion 13a along the circumferential direction. A rack portion 13f that mates with the rack portion 11a of the rack plate 11 is attached to a fixed position of the magnet portion 13b.

[0022] The Hall element 10 is fixed at a fixed position in the notch 8d of the side surface 8c. The hall element 10 detects the position of the magnet portion 13b of the cam gear 13. The detection result is output to a main control unit such as a digital camera or a mobile phone on which the lens driving device 1 is mounted. [0023] The rack plate 11 is formed of an insulating resin material, and includes a rack portion 11a accommodated in the groove portion 8i, and a flat surface portion 1 lb extending in a direction orthogonal to the rack portion 1la. The rack portion 11a and the flat surface portion l ib form a T-shaped cross section, and only the rack portion 11a is accommodated in the groove portion 8i. One end portion (the end portion on the side surface 8c side) of the plane portion l ib is bent toward the inner side of the lens driving device 1 and is engaged with the hole portion 12e of the link member 12 on the upper surface of the bent portion. Shaft 1 lc is upright. Further, on the upper surface of the other end portion (the end portion on the side surface 3 side) of the flat surface portion l ib, a locking piece 11 that locks one end of a biasing spring 15 that biases the rack plate 11 toward the side surface 8c. d is provided.

[0024] The link member 12 is formed of an insulating resin material and has a substantially arcuate shape with both ends bent to the inside of the lens driving device 1. The link member 12 connects the contact portion 12a with which the tip end portion of the rotating shaft 7b of the motor 7 described later contacts, the engagement portion 12b with which the rack plate 11 is engaged, and the contact portion 12a with the engagement portion 12b. Connecting portion 12c for transmitting the driving force of rotating shaft 7b to rack plate 11. A hole 12d that accommodates the shaft 8e is formed between the contact portion 12a and the connecting portion 12c, and a long hole 12e that accommodates the shaft 11c is formed in the engaging portion 12b.

[0025] The motor 7 includes a housing 7a having a rectangular parallelepiped shape, and a rotating shaft 7b that is accommodated in the housing 7a and whose one end force also moves in the axial direction. As will be described later, the rotary shaft 7b is configured to translate in the axial direction by controlling the voltage application timing to a plurality of piezoelectric elements attached to the outer surface of the housing 7a to displace the housing 7a. Yes. A ring 7d having a stagger 7c is fixed in the vicinity of the tip of the rotating shaft 7b. The stopper 7d functions as a protruding member, and comes into contact with restricting pieces 16a and 16b of a stopper plate 16 described later in accordance with the parallel movement of the rotating shaft 7b. The configuration of the motor 7 will be described later.

[0026] The motor holder 14 is formed of an insulating resin material, and is fixed to the upper surface of the side surface 8g of the case 8. The motor holder 14 has a base portion 14a fixed to the side surface 8g and a motor holding portion 14b for holding the vicinity of the end portion of the motor 7 (the end portion on the side surface 8i side of the case 8). The inner part of the device in the base part 14a is provided in an arc shape along the shape of the cam receiving part 8b.

[0027] The stagger plate 16 is fixed to the end of the base portion 14a (the end of the side surface 8c of the case 8). It is. The stopper plate 16 is formed with a pair of restricting pieces 16a and 16b that come into contact with the strobe 7c fixed to the rotating shaft 7b when the rotating shaft 7b moves to a fixed position and restrict the driving of the motor 7. . These restricting pieces 16a and 16b function as restricting members. The detailed configuration of the stopper plate 16 will be described later.

[0028] The rotation restricting member 17 is formed of an insulating grease material and is provided in a shape corresponding to the upper surface of the large diameter portion 6b of the lens holder 6. Specifically, it has a shape in which a part of the circular shape is missing corresponding to the space in which the motor 7 is arranged. The rotation restricting member 17 is formed with a hole 17a that holds an upper end of a biasing spring 18 to be described later. One end of a biasing spring 18 that biases the lens holder 6 downward is held in the hole 17a. In the center of the rotation restricting member 17, an opening 17b corresponding to the small diameter portion 6a is formed. A pair of groove portions 17c for accommodating the protruding pieces 6d formed in the small diameter portion 6a are formed at fixed positions of the opening portion 17b.

[0029] The shield case 9 is made of a metal material such as stainless steel, and is composed of a box-shaped member having an opening at the bottom. On the upper surface, a circular opening 9a is formed at the center. The four corners of the shield case 9 have a slightly recessed shape inside the apparatus, and mounting legs 9b are formed at the lower end thereof. The mounting leg portion 9 b protrudes slightly below the lower end portion of the shield case 9 and is accommodated in the concave portion 5 c of the base 5. Hole portions 9c that engage with the pair of protrusions 8h are formed on the side surfaces corresponding to the side surfaces 8f and 8g in the shield case.

When assembling the lens driving device 1 having such a configuration, first, the base 5 on which the IR cut filter 4 is mounted is fixed above the substrate 3 on which the image sensor 2 is mounted. Then, the lens holder 6 is attached via the cam gear 13, the hall element 10, the rack plate 11 and the link member 12 are attached, and the case 8 to which the motor 7 is attached via the motor holder 14 is mounted above the base 5. Placed on. Then, with the rotation restricting member 17 attached with the urging spring 18 mounted on the lens holder 6, the shield case 9 is covered from above and fixed to the base 5, whereby the lens driving device 1 is Assembled.

More specifically, in the process of covering the shield case 9 with the case 8, the protrusion 8 h formed on the side surface of the case 8 engages with the hole 9 c of the shield case 9. Is locked to case 8. And this lens drive by sticking with adhesive etc. Device 1 is assembled. As shown in FIG. 2, the lens driving device 1 assembled in this manner is held in a state where the opening 9d formed in the small diameter portion 6a of the lens holder 6 faces the opening 9a of the shield case 9. As will be described later, the lens holder 6 is configured to move up and down in accordance with the drive of the motor 7.

Hereinafter, an internal configuration of the lens driving device 1 assembled in this way will be described with reference to FIGS. 3 to 6. FIG. FIG. 3 is a perspective view showing the internal configuration of the lens driving device 1, and FIG. 4 is a top view showing the internal configuration of the lens driving device 1. 5 is a cross-sectional view taken along a solid line AA shown in FIG. 4, and FIG. 6 is a cross-sectional view taken along a solid line BB shown in FIG. In FIGS. 5 and 6, the lens held by the lens holder 6 is omitted.

[0033] When the lens driving device 1 is assembled in this manner, the side surface 8f of the case 8 has the rack portion 11a accommodated in the groove portion 8i so as to be mated with the rack portion 13f as shown in FIG. A rack plate 11 is attached. In this case, an urging spring 15 is disposed between the locking piece l id of the rack plate 11 and the wall portion 8k, and urges the rack plate 11 in the direction of arrow A shown in FIG. Yes.

In addition, on the side surface 8c of the case 8, as shown in FIG. 3, the Hall element 10 is fixed to the notch 8d. Further, as shown in FIGS. 3 and 4, the link member 12 is arranged so that the shaft 8e is accommodated in the hole 12d and the shaft 11c (see FIG. 4) is accommodated in the hole 12e on the upper surface of the side surface 8c. It is attached.

Further, as shown in FIGS. 3 and 4, a motor holder 14 (see FIG. 4) is attached to the upper surface of the side surface 8 g of the case 8. The motor 7 is held by the motor holding portion 14b of the motor holder 14. In this case, the tip end of the rotating shaft 7b of the motor 7 is in contact with the contact portion 12a of the link member 12, and the stopper 7c of the ring 7d fixed in the vicinity of the tip portion (FIG. 4). Is in a state of being arranged below the regulating piece 16b formed on the stagger plate 16 (initial state).

Also, the assembled lens driving device 1 has a lower end of the lens holder 6 accommodated in the opening 8a of the case 8, as shown in FIGS. It is attached to the case 8 via a cam gear 13 placed on the portion 8b. In this case, on the substrate 3 The center position of the mounted image sensor 2 is arranged so as to coincide with the center positions of the small diameter part 6a and the large diameter part 6b of the lens holder 6.

In addition, as shown in FIG. 5, the large-diameter portion 6 b of the lens holder 6 is formed with a housing portion 6 c that houses a part of the motor 7. The motor 7 is held by the motor holder 14 while being accommodated in the accommodating portion 6c. The motor 7 is held without shifting the center position of the lens holder 6 by accommodating a part of the motor 7 in the accommodating portion 6c formed in the lens holder 6 region outside the lens holder 6 in this way. It is possible to do. In the present embodiment, the inner surface of the accommodating portion 6c is provided in parallel with one side of the image sensor 2 (side 2b shown in FIG. 1). As a result, even when the accommodating portion 6c is formed, the range of image data acquired by the image sensor 2 is not limited.

Here, the configuration of the motor 7 will be described with reference to FIG. FIG. 7 is an exploded view for explaining the configuration of the motor 7 according to the present embodiment. In FIG. 7, the components described in FIG. 1 are denoted by the same reference numerals and description thereof is omitted.

[0039] The motor 7 according to the present embodiment is composed of, for example, a well-known piezoelectric actuator shown in the prior art. In the motor 7 shown in FIG. 7, the housing 7a is made of brass or the like, and is provided, for example, in the shape of a rectangular parallelepiped with its corners cut off. The rotating shaft 7b is made of, for example, a metal material such as stainless steel, and a thread having a constant pitch is formed on the outer peripheral surface thereof. A through-hole through which the rotary shaft 7b passes is formed inside the housing 7a, and a screw thread that mates with a screw thread of the rotary shaft 7b is formed on the inner peripheral surface of one of the openings. A nut 7e is attached, and a bearing 7f that rotatably holds the rotating shaft 7b is attached to the other opening. A ring 7d having a stopper 7c is fixed in the vicinity of the tip of the rotating shaft 7b protruding from the nut 7e. Piezoelectric elements 7g and 7h are attached to the upper and lower surfaces of the housing 7a, while piezoelectric elements 7i and 7j are attached to the side surfaces of the housing 7a. For example, the piezoelectric elements 7g to 7j are attached to the outer surface of the housing 7a with an adhesive or the like.

[0040] In the motor 7 having such a configuration, for example, a first power source is connected to the piezoelectric elements 7g and 7h, a second power source is connected to the piezoelectric elements 7i and 7j, and the housing 7a is grounded. Has been. When voltage is applied to the piezoelectric elements 7g and 7h, the reverse piezoelectric effect is applied. One piezoelectric element 7g (or piezoelectric element 7h) expands and the other piezoelectric element 7h (or piezoelectric element 7g) contracts. Similarly, when a voltage is applied to piezoelectric elements 7i and 7j, one piezoelectric element 7i (or piezoelectric element 7j) expands due to the reverse piezoelectric effect, and the other piezoelectric element 7j (or piezoelectric element 7i) contracts. . In the motor 7, the housing 7a is displaced by sequentially switching the timing of the voltages applied to the piezoelectric elements 7g and 7h and the piezoelectric elements 7i and 7j. Then, by causing the nut 7e attached to the housing 7a to perform an arc motion, the rotating shaft 7b engaged therewith is translated in the axial direction.

In the present lens driving device 1, such horizontal movement of the rotating shaft 7 b by the motor 7 is transmitted to the lens holder 6 through the link member 12, the rack plate 11 and the cam gear 13, and is vertically transmitted along the transmission path. Changes to movement, and the lens holder 6 moves up and down. That is, when the rotary shaft 7b moves in parallel and pushes out the contact portion 12a, the engagement portion 12b moves the rack plate 11 against the urging direction of the urging spring 15 accordingly. When the rack plate 11 moves, the cam gear 13 rotates accordingly. When the cam gear 13 rotates, the protruding piece 6f is pushed up along the shape of the cam portion 13a. As a result, the lens holder 6 moves upward. On the other hand, when the rotating shaft 7b moves in parallel and the contact portion 12a returns to the original position, the cam gear 13 rotates in the same manner, and the protruding piece 6f is pushed down along the shape of the cam portion 13a, so that the lens holder 6 Will move downward.

Next, the configuration of the stopper plate 16 will be described, and the relationship between the stopper 7c and the stopper plate 16 will be described. FIG. 8 is a perspective view for explaining the configuration of the stopper plate 16, and FIGS. 9 and 10 are perspective views for explaining the relationship between the stopper 7 c and the stopper plate 16. FIG. 8 shows the case where the stopper 7c is disposed between the restricting piece 16a and the restricting piece 16b.

The stopper plate 16 is attached to one end of the base portion 14a of the motor holder 14 as shown in FIG. The restricting pieces 16a and 16b are arranged at regular intervals along the axial direction of the rotating shaft 7b. Specifically, it is formed by bending a part of the upper side of the stopper plate 16 to the motor 7 side. A notch 16c is formed between the restricting piece 16a and the restricting piece 16b. When fixed to the motor holder 14, the tip of the stopper 7c is positioned at a position corresponding to the regulating pieces 16a and 16b, or the regulating pieces 16a and 1b. It arrange | positions in the position corresponding to the notch part 16c between 6b.

[0044] In an initial state where the motor 7 is fixed to the motor holder 14, the stopper 7c is in a state of being disposed in a lower region of the regulating piece 16b as shown in FIG. In other words, the rotating shaft 7b is in a state that does not enter the inside of the housing 7a any more. When a voltage is also applied to the piezoelectric elements 7g to 7j of the motor 7 at a predetermined timing, the rotating shaft 7b moves in the forward direction shown in FIG. 9 while rotating in the arrow direction shown in FIG. When the stopper 7c is disposed at a position passing through the notch 16c, the rotary shaft 7b moves in parallel without being restricted by the restriction pieces 16a and 16b. Then, when it moves parallel to a certain position, as shown in FIG. 10, the stopper 7c comes into contact with the upper surface of the restricting piece 16a, and the rotation of the rotating shaft 7b is restricted. As a result, the parallel movement of the rotating shaft 7b in the forward direction shown in FIG. 10 is restricted.

As described above, in the lens driving mechanism 1 according to the present embodiment, when the rotation shaft 7b is translated to the fixed position, the rotation of the rotation shaft 7b is restricted by the restriction piece 16a. The rotation of the rotating shaft 7b can be regulated with a smaller force than when the propulsive force generated on the rotating shaft 7b is received by the contact member orthogonal to the moving direction of 7b. This makes it possible to efficiently regulate the parallel movement of the rotating shaft 7b without damaging or wearing the peripheral members.

Next, the configuration of the lens holder 6 and the configuration of the lens held by the lens holder 6 will be described with reference to FIGS. FIG. 11 is a schematic diagram for explaining the configuration of the lens holder 6 and the lens held by the lens holder 6 according to the present embodiment. FIG. 11 (a) shows a cross-sectional view of the lens holder 6 with the lens held, and FIG. 11 (b) is a top view of the lens held by the lens holder 6. FIG. In FIG. 11 (b), the lens holder 6 is omitted for convenience of explanation. FIGS. 12, 13, and 14 are schematic diagrams for explaining the configurations of the first lens, the second lens, and the third lens held by the lens holder 6 according to the present embodiment, respectively.

[0047] As shown in FIG. 11 (a), the lens holder 6 has three first lenses 19, a second lens 20, and a third lens, which are formed of a resin material and have different shapes on the inner side. Store 21 along the optical axis. Here, the first lens 19 has a smaller diameter than the second lens 20, and the first lens 19 2 Located at a predetermined position on the lens 20. The second lens 20 is formed with a smaller diameter than the third lens 21 and is disposed at a predetermined position on the third lens 21. The lens holder 6 is provided in a shape along the external shape of the first lens 19, the second lens 20, and the third lens 21 that are arranged in this manner.

[0048] The first lens 19 has a lens portion 19a including a convex lens as shown in FIG. As shown in FIG. 12 (a), the lens portion 19a has a substantially circular shape when viewed from the top surface. Further, as shown in FIG. 12 (b), a bulging portion 19b that bulges upward is formed in the central portion, and an annular positioning that protrudes downward is formed on the outer peripheral edge portion thereof. Part 19c is formed. The positioning portion 19c is formed as a part of the lens portion 19a and is formed with the same accuracy as the lens portion 19a.

The second lens 20 has a lens portion 20a including a concave lens and a concave lens as shown in FIG. As shown in FIG. 13 (a), the lens portion 20a has a circular shape in which a part on the left side as viewed from above is missing. Further, as shown in FIG. 13 (b), a circular protrusion 20b that protrudes slightly upward is formed at the center, and an arc-shaped protrusion that protrudes downward is formed at the outer peripheral edge. A positioning portion 20c is formed. The central portion of the protruding portion 20c is slightly recessed downward. The positioning portion 20c is formed as a part of the lens portion 20a in the same manner as the positioning portion 19c.

As shown in FIG. 14, the third lens 21 has a lens portion 21a including an aspheric lens. As shown in FIG. 14 (a), the lens portion 21a has a substantially circular shape when viewed from above. Further, as shown in FIG. 14 (b), an arcuate positioning portion 21b protruding upward is formed on the outer peripheral edge portion thereof. The positioning portion 21b is formed as a part of the lens portion 21a, like the positioning portion 19c and the positioning portion 20c. Further, as shown in FIG. 14 (b), the lens portion 21a is formed with a flat surface portion 21c in a constant region on the left side. The flat surface portion 21c has a shape corresponding to a portion where the circular shape of the second lens 20 is missing.

[0051] When the first lens 19, the second lens 20, and the third lens 21 are stored in the lens holder 6, as shown in FIG. 11 (a), the positioning portion 19c of the first lens 19 is The first lens 19 is arranged above the second lens 20 so as to coincide with the outer peripheral surface of the protrusion 20c of the second lens 20. Then, the positioning part 20c of the second lens 20 is replaced with the positioning part 21b of the third lens 21. The second lens 20 is disposed above the third lens 21 so as to coincide with the outer peripheral surface of the second lens 20. Then, these lenses are accommodated in the lens holore 6 so that the peripheral surface portion corresponding to the flat surface portion 21 c comes into contact with the inner peripheral surface of the lens holder 6.

[0052] By overlapping the first lens 19 to the third lens 21 having such a shape in the optical axis direction, as shown in FIG. 11 (a), above the flat portion 21c of the third lens 21, No other lens is placed. Since the lens holder 6 is provided in a shape along the shapes of the first lens 19 to the third lens 21 stacked in this manner, a fixed space is provided above the flat portion 21d and outside the lens holder 6. Will be secured. In the lens driving device 1, as shown in FIG. 11 (a), a housing portion 6c is provided in this space to house the motor 7.

As described above, according to the drive restricting structure of the piezoelectric actuator according to the present embodiment, when the rotating shaft 7b is translated to the fixed position, the rotation of the rotating shaft 7b is restricted by the restricting pieces 16a and 16b. That is, the rotation of the rotating shaft 7b can be restricted with a smaller force than when the propulsive force generated on the rotating shaft 7b is received by the contact member orthogonal to the moving direction of the rotating shaft 7b. This makes it possible to efficiently regulate the parallel movement of the rotating shaft 7b without damaging or wearing the peripheral members.

[0054] In particular, according to the drive restricting structure of the piezoelectric actuator according to the present embodiment, the two restricting pieces 16a, 16b spaced apart from each other are provided along the axial direction of the rotating shaft 7b. As a result, the rotary shaft 7b is allowed to move in parallel within the interval (notch portion 16c) provided between the restricting pieces 16a and 16b, and the restricting pieces 16a and 16b can both move in the axial direction of the rotary shaft 7b. It becomes possible to regulate the parallel movement of the direction.

Note that the present invention is not limited to the above-described embodiment, and can be implemented with various modifications. In the above embodiment, the size, shape, and the like illustrated in the accompanying drawings are not limited to these, and can be appropriately changed within a range in which the effects of the present invention are exhibited. In addition, various modifications can be made without departing from the scope of the object of the present invention.

[0056] For example, in the drive restricting structure of the piezoelectric actuator described above, the force plate that constitutes the stopper plate 16 having the restricting pieces 16a and 16b as a separate member from the motor holder 14 is used. The top plate 16 may be formed integrally with the motor holder 14! In such a change, there is no need to fix the stopper plate 16 to the motor holder 14, so that the number of parts can be reduced and the manufacturing cost of the structure can be reduced.

[0057] In addition, in the above embodiment, the description will be given of the case where the drive restricting structure of the piezoelectric actuator is applied to the lens driving device 1. However, the drive of the piezoelectric actuator is described. The content of the device body to which the regulatory structure is applied is not limited to this, and can be changed as appropriate. For example, the present invention can be applied to valve devices used for various opening / closing mechanisms. In this case, it is possible to obtain the effects described above in the valve device.

Industrial applicability

As described above, the piezoelectric actuator drive restricting structure according to the present invention and the lens driving device equipped with the piezoelectric actuator control the voltage application to the piezoelectric element to rotate the rotating shaft and translate in the axial direction. When the rotary shaft moves in parallel to a certain position, the propulsive force generated on the rotary shaft by the abutting member orthogonal to the moving direction of the rotary shaft is regulated by regulating the rotation of the rotary shaft by the regulating member. The rotation of the rotating shaft is regulated with a small force compared with the case of receiving it, and the parallel movement of the rotating shaft of the piezoelectric actuator without damaging or wearing the peripheral members is efficiently regulated. There is a possibility.

Claims

The scope of the claims

[1] A drive restricting structure of a piezoelectric actuator that controls the voltage application to the piezoelectric element to rotate the rotating shaft and move in parallel in the axial direction, and projects in a direction perpendicular to the axial direction of the rotating shaft. A projecting member that rotates integrally with the shaft; and a regulating member that abuts the projecting member when the rotational shaft is translated to a certain position and regulates the rotation of the rotating shaft. Piezoelectric actuator drive restriction structure.

[2] The drive restricting structure for a piezoelectric actuator according to claim 1, wherein the two restricting members spaced apart from each other are arranged along the axial direction of the rotating shaft.

[3] The drive restriction structure for a piezoelectric actuator according to claim 1 or 2, wherein the restriction member is formed integrally with a holding member for holding the piezoelectric actuator.

[4] A lens driving device comprising the piezoelectric actuator drive restricting structure according to any one of claims 1 to 3.