Lens drive unit

Abstract

A lens holding part that holds at least one lens, a support shaft that movably supports the lens holding part in a first direction that is the optical axis direction of the lens, an actuator having a drive shaft that extends in the first direction and vibrates in the first direction, and a base to which the support shaft and the actuator are fixed, wherein the lens holding part has a first engaging part having a pair of friction surfaces that sandwich the drive shaft.

Description

Technical Field

[0001] The present invention relates to a lens drive unit that drives a lens in the optical axis direction.

Background Art

[0002] Conventionally, a lens drive unit that includes a small actuator using a piezoelectric element that expands and contracts in a predetermined direction and drives a lens in the optical axis direction is known (see Japanese Patent Application Laid-Open No. 2015-105988).

[0003] As shown in FIGS. 8 and 9, this lens drive unit 100 includes a device main body 101, an actuator 104 held by the device main body 101, and a moving member 105 driven by the actuator 104.

[0004] The device main body 101 includes a holding member 102 and a cover 103. The holding member 102 includes an actuator holding portion 121 that holds the actuator 104 at a first corner portion 102a, and has a third support column 120c at a third corner portion 102c disposed at a diagonal position to the first corner portion 102a. This third support column 120c has a regulation portion receiving groove 122 into which a part (rotation regulation portion) 161 of the moving member 105 is fitted so as to be movable in the vertical direction.

[0005] The actuator 104 includes a piezoelectric element 141 that expands and contracts in a predetermined direction, and a drive shaft 142 joined to one end of the piezoelectric element 141.

[0006] The moving member 105 has a substantially cylindrical moving member main body portion 106 and an engaging member 107 that engages with the drive shaft 142 with a predetermined frictional force.

[0007] The moving member main body portion 106 holds at least one lens on the inner peripheral side, and has a rotation regulation portion 161 that protrudes in the radial direction of the lens and regulates the rotation of the moving member 105 with respect to the drive shaft 142 on the outer periphery.

[0008] The engaging member 107 includes a strip-shaped engaging member body 171 made of metal and having elasticity, and a strip-shaped elastic body 173 made of metal and having elasticity.

[0009] The engaging member body 171 is provided with a drive bearing portion 172 formed by a first receiving portion 172a and a second receiving portion 172b extending substantially at a right angle from the first receiving portion 172a on one end side in the longitudinal direction.

[0010] The elastic body 173 is provided with a pressing portion 173a that presses the drive shaft 142 against the drive bearing portion 172 on one end side in the longitudinal direction. Then, the drive shaft 142 is sandwiched between the drive bearing portion 172 and the pressing portion 173a of the engaging member 107 connected to the moving member main body portion 106. Thereby, the engaging member 107 engages with the drive shaft 142 so as to be slidable in the axial direction.

[0011] In the lens drive unit 100 configured as described above, when power is supplied from a drive circuit provided in a mobile terminal or the like to the piezoelectric element 141, the piezoelectric element 141 vibrates in the axial direction, and the drive shaft 142 reciprocates due to the vibration (expansion and contraction), and the moving member 105 moves in the axial direction (optical axis direction) of the drive shaft 142 due to the reciprocating movement.

[0012] However, in this lens drive unit 100, the moving member 105 holding at least one lens reciprocates in the axial direction (optical axis direction) of the drive shaft 142 while being supported only by the actuator 104, that is, the weight of the lens, the moving member 105, etc. is all applied to the actuator 104. Therefore, when an impact is applied to a mobile phone or the like equipped with the lens drive unit 100, the actuator 104 may be damaged.

Prior Art Documents

Patent Documents

[0013]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0014] Therefore, an object of the present invention is to provide a lens drive unit in which it is difficult for a load to be applied to an actuator.

Means for Solving the Problems

[0015] The lens drive unit according to the present invention includes: a lens holding part that holds at least one lens; a support shaft that movably supports the lens holding part in a first direction that is the optical axis direction of the lens; an actuator having a drive shaft that extends in the first direction and vibrates in the first direction; a base to which the support shaft and the actuator are fixed, wherein the lens holding part has a first engagement part having a pair of friction surfaces that sandwich the drive shaft.

[0016] In the lens drive unit, the actuator may have a piezoelectric element that is connected to one end of the drive shaft and reciprocates the drive shaft in the first direction by expanding and contracting in the first direction.

[0017] Also, in the lens drive unit, the support shaft may movably support the lens holding part in the first direction by magnetic force.

[0018] Also, in the lens drive unit, the support shaft extends in the first direction and is formed of a magnetic material, and the lens holding part may have a second engagement part that engages with the support shaft.

[0019] The second engagement part has an insertion hole that penetrates in the first direction and into which the support shaft is inserted, It may also have a magnet disposed at a position where the inner peripheral surface of the insertion hole is pressed in a second direction orthogonal to the first direction with respect to the support shaft.

[0020] Also, in the lens drive unit, the lens holding portion has a holding portion main body that surrounds the periphery of the at least one lens, the first engaging portion and the second engaging portion may be disposed on both sides of the holding portion main body in the radial direction of the lens as viewed from the first direction.

[0021] Also, in the lens drive unit, the pair of friction surfaces may each extend in a surface direction orthogonal to a third direction orthogonal to each of the first direction and the second direction and sandwich the drive shaft in the third direction.

[0022] Also, in the lens drive unit, the lens holding portion has a holding portion main body that surrounds the periphery of the at least one lens, and a plurality of extending portions each extending from the holding portion main body at intervals in the first direction, each of the plurality of extending portions may have the insertion hole at a position overlapping as viewed from the first direction.

[0023] Also, in the lens drive unit, the lens holding portion has a holding portion main body that surrounds the periphery of the at least one lens, and a pair of extending portions extending from the holding portion main body at intervals in the first direction, the pair of extending portions are included in the second engaging portion and engage with the support shaft so as to be movable in the first direction with respect to the support shaft, the center of gravity of the lens holding portion in a state of holding the at least one lens may be located between the pair of extending portions in the first direction.

[0024] Also, the lens drive unit A cover member that constitutes a housing together with the base portion may be provided.

[0025] Also, in the lens driving unit, at the support shaft, one side portion in the first direction of the engagement portion with the second engagement portion may be fixed to the base portion, and the other side portion in the first direction of the engagement portion with the second engagement portion may be fixed to the housing.

[0026] Also, in the lens driving unit, the first engagement portion may be configured by bending a strip-shaped metal member into a predetermined shape.

[0027] Also, in the lens driving unit, the pair of friction surfaces may be included in the surface of the strip-shaped metal member.

[0028] Also, in the lens driving unit, the force with which the pair of friction surfaces sandwich the drive shaft may be generated by the spring property of the strip-shaped metal member.

Brief Description of the Drawings

[0029]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

DETAILED DESCRIPTION OF THE INVENTION

[0030] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

[0031] The lens driving unit of this embodiment is incorporated in a portable terminal such as a smartphone, and is used to drive a lens or a lens group in the optical axis direction to focus in the camera of the portable terminal (that is, perform autofocus).

[0032] As shown in FIGS. 1 to 6, this lens driving unit 1 includes a lens holding portion 2 that holds at least one lens R, a support shaft 3 that movably supports the lens holding portion 2 in the direction D1 in which the optical axis C of the lens R extends (optical axis direction (first direction)), and an actuator 4 that drives the lens holding portion 2 in the optical axis direction D1. Further, the lens driving unit 1 includes a housing 5 that surrounds the lens holding portion 2, the support shaft 3, and the actuator 4, and a substrate portion 6 that is disposed in the housing 5 and controls the driving of the actuator 4.

[0033] The support shaft 3 movably supports the lens holding portion 2 in the optical axis direction D1 by magnetic force. Specifically, the support shaft 3 is a member that extends in the optical axis direction D1 and is formed of a magnetic material such as iron (specifically, a ferromagnetic material). The support shaft 3 of this embodiment is a cylindrical member that extends in the optical axis direction D1, and the outer diameter at each position in the optical axis direction D1 is the same.

[0034] The actuator 4 is a so-called piezoelectric actuator having a piezoelectric element 42, and the actuator 4 of the present embodiment is a Smooth Impact Drive Mechansim (SIDM).

[0035] Specifically, the actuator 4 has a drive shaft 41 extending in the optical axis direction D1, and a piezoelectric element 42 connected to one end of the drive shaft 41 and expanding and contracting in the optical axis direction D1. Further, the actuator 4 has a weight portion 43 connected to the side opposite to the drive shaft 41 of the piezoelectric element 42.

[0036] The drive shaft 41 of the present embodiment is a cylindrical shaft member extending in the optical axis direction D1. Further, the piezoelectric element 42 is an element that converts input electrical energy into mechanical energy that expands and contracts, that is, mechanical motion. For example, it is an element that converts input electrical energy into mechanical expansion and contraction motion by the piezoelectric effect. This piezoelectric element 42 reciprocates the drive shaft 41 in the optical axis direction D1 using this expansion and contraction motion. These drive shaft and piezoelectric element 42 are connected by an adhesive. Further, the weight portion 43 is for generating displacement due to the expansion and contraction of the piezoelectric element 42 only on the drive shaft 41 side.

[0037] The housing 5 has a base portion 51 to which the support shaft 3 and the actuator 4 are fixed, and a cover member 52 that constitutes the housing 5 in cooperation with the base portion 51. The housing 5 of the present embodiment has a substantially rectangular parallelepiped shape and is substantially square when viewed from the optical axis direction D1.

[0038] The base portion 51 extends in a direction orthogonal to the optical axis direction D1 and has a first optical path opening 511 penetrating in the optical axis direction D1 at the center. Further, the base portion 51 has a first holding portion 512 that holds the support shaft 3 and a second holding portion 513 that holds the actuator 4. These first holding portion 512 and second holding portion 513 are arranged at two corner portions (first corner portion 51a, second corner portion 51b) facing in a predetermined diagonal direction (second direction) D2 of the base portion 51 when viewed from the optical axis direction D1.

[0039] The first holding portion 512 of the present embodiment is a through hole that penetrates in the optical axis direction D1, and the support shaft 3 is fixed to the first holding portion (through hole) 512 with one end portion of the support shaft 3 inserted therein (see FIG. 6). Further, the second holding portion 513 of the present embodiment is also a through hole that penetrates in the optical axis direction D1, and the actuator 4 (weight portion 43) is fixed to the second holding portion 513 with the weight portion 43 of the actuator 4 inserted therein (see FIG. 5).

[0040] The cover member 52 has a plate-like portion 521 that extends in a direction orthogonal to the optical axis direction D1, and a peripheral wall portion 522 that extends from the periphery of the plate-like portion 521 toward the base portion 51. The plate-like portion 521 has a first optical path opening 523 that penetrates in the optical axis direction D1 at the center. Further, the plate-like portion 521 has a cover-side holding portion 524 at a position corresponding to the first holding portion 512 and the second holding portion 513 of the base portion 51, and a through hole 525 that penetrates in the optical axis direction D1. The driving shaft 41 (specifically, the tip portion of the driving shaft 41) of the actuator 4 is inserted into the through hole 525 so as to be reciprocally movable (vibratable) in the optical axis direction D1. Further, the cover-side holding portion 524 of the present embodiment is a through hole that penetrates in the optical axis direction D1, and the support shaft 3 is fixed to the cover-side holding portion 524 with the other end portion of the support shaft 3 inserted therein.

[0041] The lens holding portion 2 has a holding portion main body 20 that holds the lens R or a lens group (a plurality of lenses), a first engaging portion 21 that engages with the actuator 4, and a second engaging portion 22 that engages with the support shaft 3. Further, the lens holding portion 2 also has a detection magnet 23 for detecting the position or movement amount of the lens holding portion 2 in the optical axis direction D1.

[0042] The holding portion main body 20 is a cylindrical or frame-shaped member that holds the lens R or the lens group (a plurality of lenses) so as to surround the periphery of the lens R or the lens group. The holding portion main body 20 of the present embodiment is made of resin and holds one lens R. In the case where the holding portion main body 20 holds a lens group including a plurality of lenses R, each lens R is held so that their optical axes C coincide with each other.

[0043] The first engaging portion 21 has a pair of friction surfaces 211 that sandwich the drive shaft 41 of the actuator 4 (see FIG. 5), and is arranged at one end of the holding portion main body 20 in a predetermined diagonal direction D2, which is the direction connecting the first corner portion 51a and the second corner portion 51b of the base portion 51 (specifically, the direction connecting the support shaft 3 and the actuator 4). The first engaging portion 21 of the present embodiment is configured by bending a metal strip-shaped member into a predetermined shape.

[0044] The pair of friction surfaces 211 of the first engaging portion 21 extend in a surface direction orthogonal to the sandwiching direction (third direction) D3 that is orthogonal to each of the optical axis direction D1 and the diagonal direction D2, and sandwich the drive shaft 41 in the sandwiching direction. The force for sandwiching the drive shaft 41 by the pair of friction surfaces 211 is a force generated by the elastic force (spring property) of the first engaging portion 21 (metal strip-shaped member), and is set such that a predetermined frictional force acts between the drive shaft 41 and the first engaging portion 21.

[0045] The second engaging portion 22 has an insertion portion 220 that penetrates in the optical axis direction D1 and through which the support shaft 3 is inserted, and a support magnet 225 that exerts a magnetic attraction force on the support shaft 3, and is arranged at the other end of the holding portion main body 20 in the diagonal direction D2.

[0046] The insertion portion 220 has a plurality of extended portions 221 that extend from the holding portion main body 20 in the other side of the diagonal direction D2 (the direction away from the holding portion main body 20). Each of these plurality of extended portions 221 extends from the holding portion main body 20 at intervals in the optical axis direction D1. In the insertion portion 220 of the present embodiment, a pair of extended portions 221 extend from the holding portion main body 20 at intervals in the optical axis direction D1.

[0047] Each extended portion 221 is a plate-shaped portion that extends in a surface direction orthogonal to the optical axis direction D1, and is arranged at intervals in the optical axis direction D1. Each extended portion 221 of the present embodiment is arranged at intervals in the optical axis direction D1 such that the center of gravity G of the lens holding portion 2 in a state where the lens R is held is located at any position between the pair of extended portions 221 in the optical axis direction D1 (see FIG. 7).

[0048] In addition, each extended portion 221 has a through hole (insertion hole) 222 that penetrates in the optical axis direction D1 at a position overlapping when viewed from the optical axis direction D1. The through hole 222 of the present embodiment is a circular hole, and the inner diameter of each through hole 222 is slightly larger than or the same as the outer diameter of the support shaft 3.

[0049] The support magnet 225 is disposed at a position that presses against the inner peripheral surface 223 of the through hole (insertion hole) 222 of each extended portion 221 in the diagonal direction D2 with respect to the support shaft 3. Specifically, the support magnet 225 is disposed at a position on the other side (the right side in FIG. 6) of the support shaft 3 in the diagonal direction D2. More specifically, the support magnet 225 is disposed at a position on the other side of each extended portion 221 in the diagonal direction D2. This support magnet 225 has magnetic poles arranged in the diagonal direction D2 and extends from the position of one extended portion 221 to the position of the other extended portion 221 in the optical axis direction D1.

[0050] The strength of this support magnet 225 (the strength of the magnetic attraction force) is set so that when the lens drive unit 1 is arranged such that the optical axis direction D1 coincides with the vertical direction, the lens holding portion 2 in the state of holding the lens R does not rattle (tilt) with respect to the support shaft 3. In the lens drive unit 1 of the present embodiment, it is as follows.

[0051] As shown in FIG. 7, the distance from the center of gravity G of the lens holding portion 2 in the state of holding the lens R to the axis of the support shaft 3 is defined as L1, and the distance from the center of gravity G of the support shaft 3 in the optical axis direction D1 to the contact positions (in FIG. 7, the center positions in the dimension of the inner peripheral surface 223 in the optical axis direction D1) α1, α2 with the inner peripheral surface 223 of each extended portion 221 is defined as L2, the force (gravity) applied at the center of gravity G position is defined as F1, and the force due to the magnetic attraction force of the support magnet 225 is defined as F2. Note that the contact point α1 is a point assumed to be the contact position in the inverted state described later, and the contact point α2 is a point assumed to be the contact position in the upright state described later.

[0052] In this embodiment, when the axial direction of the support shaft 3 coincides with the vertical direction and the upward direction is defined as the direction in which the lens holding portion 2 moves away from the base portion 51 (the posture shown in FIG. 7), it is defined as the upright position. When it faces the opposite direction of the upright position (when the downward direction is defined as the direction in which the lens holding portion 2 moves away from the base portion 51), it is defined as the inverted position. When the axis of the support shaft 3 coincides with the horizontal direction and the lens holding portion 2 is located below the support shaft 3, it is defined as the horizontal position. The following relationships hold. Upright position: L1 × F1 = L2 × F2 ···(1) Inverted position: L1 × F1 = L2 × F2 ···(2) Horizontal position: F1 = F2 ···(3) In the lens drive unit 1 of this embodiment, assuming that L1 = 7.5 mm, L2 = 1.5 mm, and the self-weight of the lens holding portion 2 in the state of holding the lens R is 1.5 g, F1 = mfg = 1.5fg = 15 mN Therefore, From the above (1), F2 = 75 mN From the above (2), F2 = 75 mN From the above (3), F2 = 15 mN are obtained. Assuming a safety factor of 2, F2 = 150 mN = 15 gf From the above, the magnetic attraction force of the support magnet 225 is set to 15 gf. In the above calculation, it is assumed that the engagement between the first engagement portion 21 of the lens holding portion 2 and the actuator 4 is not considered, and the lens holding portion 2 in the state of holding the lens R is supported only by the support shaft 3.

[0053] Returning to FIGS. 1 to 6, the detection magnet 23 is disposed on the circumferential surface of the holding portion main body 20. The detection magnet 23 of this embodiment is disposed at a position facing the substrate portion 6 on the circumferential surface of the holding portion main body 20 (see FIG. 4).

[0054] The substrate portion 6 includes a circuit portion 61 for supplying power to the piezoelectric element 42 of the actuator 4 and a position sensor 62 for detecting the position or movement amount of the lens holding portion 2 in the optical axis direction D1. The position sensor 62 of this embodiment is a Hall element.

[0055] In the lens drive unit 1 configured as described above, in the actuator 4, when power is supplied from the circuit unit 61 to the piezoelectric element 42, the piezoelectric element 42 vibrates (expands and contracts) in the optical axis direction D1, and due to this vibration, the drive shaft 41 reciprocates in the optical axis direction D1, and due to this reciprocation, the lens holding unit 2 moves in the axial direction (optical axis direction D1) of the drive shaft 41. As a result, in the camera of a mobile terminal such as a smartphone incorporating the lens drive unit 1, the lens R moves in the optical axis direction D1, and autofocus is performed.

[0056] More specifically, when a rectangular wave with a predetermined duty ratio is applied to the piezoelectric element 42, the displacement of the drive shaft 41 becomes triangular wave-shaped, and by changing the duty ratio of the rectangular wave, triangular waves with different slopes are generated during the rising and falling of the amplitude. The drive mechanism of the actuator 4 utilizes this.

[0057] For example, by slowly moving the drive shaft 41 in the extending direction of the piezoelectric element 42, the lens holding unit 2 engaged with the drive shaft 41 by the pair of friction surfaces 211 also moves according to the movement in the extending direction, and instantaneously when exceeding the static frictional force between the pair of friction surfaces 211 and the drive shaft 41, if the drive shaft 41 is moved in the contracting direction of the piezoelectric element 42, the lens holding unit 2 is left at the same position due to the inertial force. By repeating such reciprocation in the axial direction of the drive shaft 41, the lens holding unit 2 moves in the axial direction (optical axis direction D1) of the drive shaft 41.

[0058] The above lens drive unit 1 includes a lens holding unit 2 that holds at least one lens R, a support shaft 3 that movably supports the lens holding unit 2 in the optical axis direction (first direction) D1 of the lens R, an actuator 4 having a drive shaft 41 that extends in the optical axis direction D1 and vibrates in the optical axis direction D1, and a base portion 51 to which the support shaft 3 and the actuator 4 are fixed. And the lens holding unit 2 has a first engaging portion 21 having a pair of friction surfaces 211 that sandwich the drive shaft 41.

[0059] In this way, with the support shaft 3 supporting the lens holding part 2 so as to be movable in the optical axis direction D1, by adopting a configuration in which the actuator 4 supplies a driving force for moving the lens holding part 2 in the optical axis direction D1, the load caused by the weight of the lens R and the lens holding part 2 or the like can be prevented from being applied to the actuator 4. That is, it becomes difficult for a load to be applied to the actuator 4.

[0060] Further, in the lens driving unit 1 of the present embodiment, the actuator 4 has a piezoelectric element 42 that is connected to one end of the drive shaft 41 and expands and contracts in the optical axis direction (first direction) D1 to reciprocate the drive shaft 41 in the optical axis direction D1.

[0061] Further, in the lens driving unit 1 of the present embodiment, the support shaft 3 supports the lens holding part 2 so as to be movable in the optical axis direction D1 by magnetic force.

[0062] According to such a configuration, by adjusting the magnitude of the magnetic force, when the driving force from the actuator 4 is not applied to the lens holding part 2, the position of the lens holding part 2 in the optical axis direction with respect to the support shaft 3 is fixed, while when the driving force from the actuator 4 is applied to the lens holding part 2, a configuration that allows the lens holding part 2 to move in the optical axis direction D1 with respect to the support shaft 3 can be easily realized.

[0063] Further, in the lens driving unit 1 of the present embodiment, the support shaft 3 is formed of a magnetic material, and the lens holding part 2 has a second engaging part 22 that engages with the support shaft 3.

[0064] Further, in the lens driving unit 1 of the present embodiment, the second engaging part 22 has a through hole (insertion hole) 222 that penetrates in the optical axis direction (first direction) D1 and through which the support shaft 3 is inserted, and a support magnet (magnet) 225 that is disposed at a position where the inner peripheral surface 223 of the through hole 222 is pressed against the support shaft 3 in the diagonal direction (second direction) D2 with respect to the support shaft 3.

[0065] By using the magnetic force of the support magnet 225 in this way, a configuration in which the support shaft 3 supports the lens holding part 2 so as to be movable in the optical axis direction D1 can be easily realized.

[0066] Also, in the lens driving unit 1 of the present embodiment, the lens holding unit 2 has a holding unit main body 20 that surrounds the periphery of the lens R, and the first engaging portion 21 and the second engaging portion 22 are arranged on both sides of the holding unit main body 20 in a predetermined radial direction (diagonal direction D2 in the example of the present embodiment) of the lens R when viewed from the optical axis direction (first direction) D1.

[0067] In this way, by arranging the first engaging portion 21 on the opposite side of the diagonal direction D2 of the holding unit main body 20 with respect to the second engaging portion 22, the force from the holding unit main body 20 applied to the support shaft 3 via the second engaging portion 22 (such as the force caused by the own weight of the holding unit main body 20 and the lens R), that is, the load can be suppressed.

[0068] Also, in the lens driving unit 1 of the present embodiment, the pair of friction surfaces 211 each extend in a surface direction orthogonal to the clamping direction (third direction) D3 and sandwich the drive shaft 41 in the clamping direction D3.

[0069] Since the lens holding unit 2 is supported by the support shaft 3 by the magnetic force (magnetic attraction force) of the support magnet 225 pressing each inner peripheral surface 223 of the through hole 222 against the support shaft 3 in the diagonal direction D2, when an impact or the like is applied to the device or the like including the lens driving unit 1, the lens holding unit 2 may slightly move in the diagonal direction (the direction in which each inner peripheral surface 223 separates from the support shaft 3) D2 with respect to the support shaft 3. However, since the pair of friction surfaces 211 sandwich the drive shaft 41 in the clamping direction (direction orthogonal to the diagonal direction D2) D3, the pair of friction surfaces 211 can relatively move in the diagonal direction D2 with respect to the drive shaft 41. Thereby, it is possible to prevent a large load caused by the movement of the lens holding unit 2 in the diagonal direction D2 from being applied to the actuator 4 (drive shaft 41).

[0070] In addition, in the lens driving unit 1 of the present embodiment, the lens holding unit 2 includes a holding unit main body 20 that surrounds the periphery of the lens R, and a plurality of extending portions 221 that extend from the holding unit main body 20 at intervals in the optical axis direction (first direction) D1. Each of the plurality of extending portions 221 has an insertion hole 222 at a position that overlaps when viewed from the optical axis direction D1.

[0071] It is possible to reduce the weight compared to the block-shaped second engaging portion that occupies the entire arrangement region of the plurality of extending portions 221, and the postures of the plurality of extending portions 221 with respect to the support shaft 3 of the lens holding unit 2 are stabilized by arranging them at intervals in the optical axis direction D1.

[0072] In addition, in the lens driving unit 1 of the present embodiment, the lens holding unit 2 includes a holding unit main body 20 that surrounds the periphery of the lens R, and a pair of extending portions 221 that extend from the holding unit main body 20 at intervals in the optical axis direction (first direction) D1. The pair of extending portions 221 are included in the second engaging portion 22 and engage with the support shaft 3 so as to be movable in the optical axis direction D1 with respect to the support shaft 3. The center of gravity G of the lens holding unit 2 in the state of holding the lens R is located between the pair of extending portions 221 in the optical axis direction D1.

[0073] When the center of gravity G of the lens holding unit 2 or the like is located between the pair of extending portions 221 in the optical axis direction D1 in this way, when the lens driving unit 1 is in a posture such that the extending direction of the support shaft 3 (that is, the optical axis direction D1) is the vertical direction, the direction of the force (such as the force caused by the own weight of the lens holding unit or the like) applied to the support shaft 3 through the inner peripheral surface 223 of each insertion hole 222 of the pair of extending portions 221 is reversed. In this way, the load on the support shaft 3 is suppressed by changing the direction of the force applied to the support shaft 3.

[0074] In addition, the lens driving unit 1 of the present embodiment includes a cover member 52 that forms the housing 5 together with the base 51.

[0075] According to such a configuration, since each component member such as the actuator 4, the support shaft 3, and the lens holding unit 2 is surrounded by the housing 5, it is protected.

[0076] In addition, in the lens drive unit 1 of the present embodiment, at the support shaft 3, at the engagement site with the second engagement portion 22 (in the example of the present embodiment, the site from one extension portion 221 to the other extension portion 221 in the optical axis direction (first direction) D1), one side portion in the optical axis direction D1 is fixed to the base portion 51, and the other side portion in the optical axis direction D1 of the engagement site with the second engagement portion 22 is fixed to the cover member 52.

[0077] In this way, since both sides of the engagement site of the support shaft 3 with the second engagement portion 22 are fixed to the housing 5, the strength of the support shaft 3 against the force applied from the lens holding portion 2 is improved, so that damage to the support shaft 3 when an impact is applied to a mobile terminal or the like in which the lens drive unit is disposed can be prevented.

[0078] In addition, in the lens drive unit 1 of the present embodiment, the first engagement portion 21 is configured by bending a strip-shaped metal member into a predetermined shape. In this way, by configuring the first engagement portion 21 by bending the strip-shaped metal member, the configuration of the first engagement portion 21 can be simplified.

[0079] In addition, in the lens drive unit 1 of the present embodiment, the pair of friction surfaces 211 are included in the surface of the strip-shaped metal member. By adopting such a configuration in which the drive shaft 41 of the actuator 4 is sandwiched by one member (the strip-shaped metal member), the number of parts can be reduced as compared with a configuration in which the drive shaft 41 is sandwiched by a plurality of members.

[0080] In addition, in the lens drive unit 1 of the present embodiment, the force with which the pair of friction surfaces 211 sandwich the drive shaft 41 is generated by the spring property of the strip-shaped metal member. By adopting such a configuration in which the drive shaft 41 is sandwiched by utilizing the spring property of the strip-shaped metal member, the configuration can be simplified.

[0081] Furthermore, the lens driving unit of the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the present invention. For example, the configuration of one embodiment can be added with the configuration of another embodiment, and a part of the configuration of one embodiment can be replaced with the configuration of another embodiment. Further, a part of the configuration of one embodiment can be deleted.

[0082] In the lens driving unit 1 of the above embodiment, the support magnet 225 is arranged on the holding part main body 20 side (the right side in FIG. 6) with respect to the support shaft 3 in the diagonal direction D2, but is not limited to this configuration. In the diagonal direction D2, the support magnet 225 may be arranged on the side opposite to the holding part main body 20 with respect to the support shaft 3 (the left side in FIG. 6).

[0083] Also, in the lens driving unit 1 of the above embodiment, the support shaft 3 supports the lens holding part 2 so as to be movable in the optical axis direction D1 by applying the magnetic attraction force of the support magnet 225 that constitutes the second engagement part 22 of the lens holding part 2 to the support shaft 3 made of a magnetic material, but is not limited to this configuration. For example, the support shaft 3 may be constituted by a magnet, and a magnetic material (specifically, a ferromagnetic material such as iron) may be arranged at the second engagement part 22 of the lens holding part 2, and the support shaft 3 supports the lens holding part 2 so as to be movable in the optical axis direction D1 by applying the magnetic attraction force of this support shaft 3 to the magnetic material of the second engagement part 22.

[0084] Also, the specific configuration in which the support shaft 3 supports the lens holding part 2 so as to be movable in the optical axis direction D1 is not limited. The configuration in which the support shaft 3 supports the lens holding part 2 so as to be movable in the optical axis direction D1 does not have to be a configuration using magnetic force.

[0085] Also, in the lens driving unit 1 of the above embodiment, the support shaft 3 and the actuator 4 are arranged on both sides of the lens holding part 2 in the radial direction (diagonal direction D2) of the lens R, that is, at positions sandwiching the lens R in the radial direction (specifically, the diameter direction passing through the optical axis C position of the lens R), but they may be arranged at other positions.

[0086] In addition, in the lens driving unit 1 of the above-described embodiment, although the pair of friction surfaces 211 are arranged on one member, the present invention is not limited to this configuration. Each of the pair of friction surfaces 211 may be arranged on different members.

[0087] Further, in the insertion portion 220 of the lens driving unit 1 of the above-described embodiment, the through hole (insertion hole) 222 through which the support shaft 3 is inserted is a circular hole, but may be a polygonal hole.

[0088] In addition, in the lens driving unit 1 of the above-described embodiment, although the support shaft 3 supports the lens holding portion 2 so as to be movable in the optical axis direction D1 by magnetic force, the present invention is not limited to this configuration. Any other configuration may be used as long as the support shaft 3 can support the lens holding portion 2 so as to be movable in the optical axis direction D1.

[0089] In order to describe the present invention, the present invention has been appropriately and fully described through embodiments with reference to the drawings above. However, it should be recognized that those skilled in the art can easily make changes and / or improvements to the above-described embodiments. Therefore, as long as the changes or improvements made by those skilled in the art do not depart from the scope of the claims described in the claims, such changes or improvements are construed as being included in the scope of the claims of the claims.

Explanation of Reference Numerals

[0090] 1…Lens driving unit, 2…Lens holding part, 20…Holding part main body, 21…First engaging part, 211…Friction surface, 22…Second engaging part, 220…Insertion part, 221…Extended part, 222…Through hole (insertion hole), 223…Inner peripheral surface, 225…Support magnet (magnet), 23…Detection magnet, 3…Support shaft, 4…Actuator, 41…Drive shaft, 42…Piezoelectric element, 43…Weight part, 5…Housing, 51…Base part, 51a…First corner part, 51b…Second corner part, 511…First optical path opening part, 512…First holding part, 513…Second holding part, 52…Cover member, 521…Plate-like part, 522…Peripheral wall part, 523…First optical path opening part, 524…Cover side holding part, 525…Through hole, 6…Substrate part, 61…Circuit part, 62…Position sensor, 100…Lens driving unit, 101…Device main body, 102…Holding member, 102a…First corner part, 102c…Third corner part, 120c…Third support column, 121…Actuator holding part, 122…Regulation part receiving groove, 103…Cover, 104…Actuator, 141…Piezoelectric element, 142…Drive shaft, 105…Moving member, 106…Moving member main body part, 161…Rotation regulation part, 107…Engaging member, 171…Engaging member main body, 172…Drive shaft receiving part, 172a…First receiving part, 172b…Second receiving part, 173…Elastic body, 173a…Pressing part, C…Optical axis, D1…Optical axis direction, D2…Diagonal direction, D3…Clamping direction, G…Center of gravity, R…Lens, α1, α2…Contact points

Claims

1. a lens holding part that holds at least one lens; a support shaft that movably supports the lens holding part in a first direction which is the optical axis direction of the lens; an actuator having a drive shaft that extends in the first direction and vibrates in the first direction; a base to which the support shaft and the actuator are fixed, and comprising: The lens holding unit has a first engaging portion having a pair of friction surfaces that sandwich the drive shaft.

2. The actuator has a piezoelectric element that is connected to one end of the drive shaft and reciprocates the drive shaft in the first direction by expanding and contracting in the first direction, according to the lens drive unit of Claim 1.

3. The support shaft movably supports the lens holding part in the first direction by magnetic force, according to the lens drive unit of Claim 1 or 2.

4. The support shaft extends in the first direction and is formed of a magnetic material, The lens holding unit has a second engaging portion that engages with the support shaft, according to any one of Claims 1 to 3.

5. The second engaging portion is a through hole that penetrates in the first direction and through which the support shaft is inserted, a magnet disposed at a position where the inner peripheral surface of the through hole is pressed against the support shaft in a second direction orthogonal to the first direction, according to the lens drive unit of Claim 4.

6. The lens holding unit has a holding part main body that surrounds the periphery of the at least one lens, The first engaging portion and the second engaging portion are disposed on both sides of the holding part main body in the radial direction of the lens as viewed from the first direction, according to the lens drive unit of Claim 4 or 5.

7. The pair of friction surfaces each extend in a plane direction orthogonal to a third direction orthogonal to each of the first direction and the second direction and sandwich the drive shaft in the third direction, according to any one of Claims 1 to 6.

8. The lens holding unit is a holding part main body that surrounds the periphery of the at least one lens, a plurality of extending parts each extending from the holding part main body at intervals in the first direction, and having: Each of the plurality of extending parts has the through hole at a position overlapping as viewed from the first direction, according to the lens drive unit of Claim 5.

9. The lens holding unit is a holding part main body that surrounds the periphery of the at least one lens, a pair of extending portions extending from the holding portion main body at intervals in the first direction; the pair of extending portions are included in the second engaging portion and engage with the support shaft so as to be movable in the first direction with respect to the support shaft; the center of gravity of the lens holding portion in a state where the at least one lens is held is located between the pair of extending portions in the first direction. The lens driving unit according to any one of claims 4 to 6 and 8. **Claim 10** The lens driving unit according to any one of claims 4 to 6, 8, and 9, further comprising a cover member that constitutes a housing together with the base portion. **Claim 11** On the support shaft, one side portion in the first direction of the engaging portion with the second engaging portion is fixed to the base portion, and the other side portion in the first direction of the engaging portion with the second engaging portion is fixed to the cover member. The lens driving unit according to claim 10. **Claim 12** The first engaging portion is configured by bending a strip-shaped metal member into a predetermined shape. The lens driving unit according to any one of claims 1 to 11. **Claim 13** The pair of friction surfaces are included in the surface of the strip-shaped metal member. The lens driving unit according to claim 12. **Claim 14** The force with which the pair of friction surfaces sandwich the drive shaft is generated by the spring property of the strip-shaped metal member. The lens driving unit according to claim 13.

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