Lens driving device and camera module

Abstract

A lens driving device (101) comprises a piezoelectric driving unit (PD), a receiving member (5) that contacts the piezoelectric driving unit (PD), and a biasing member (6) that biases the piezoelectric driving unit (PD) toward the receiving member (5). The biasing member (6) has a fixed part (6A), a support part (6S) that supports the piezoelectric driving unit (PD), and an elastic deformation part (6E) that is provided between the fixed part (6A) and the support part (6S). The piezoelectric driving unit (PD) has a contacting member (9) that is fixed to one surface on an X2 side of a piezoelectric element (8), and a flexible wiring substrate (10) that is fixed to the other surface of the piezoelectric element (8). The piezoelectric element (8) and the contacting member (9) are fixed by a first adhesive (AD1), the flexible wiring substrate (10) and the support part (6S) are fixed by a third adhesive (AD3), and the Young's modulus of the third adhesive (AD3) is smaller than the Young's modulus of the first adhesive (AD1).

Description

[Technical Field]

[0001] The present disclosure relates to a lens driving device and a camera module that are mounted on, for example, a mobile device with a camera. [Background technology]

[0002] Conventionally, there is known a lens driving unit (lens driving device) that can move a lens carrier (lens holding member) in the optical axis direction relative to a module base (base member) by friction drive using bending vibration of a piezoelectric element (see Patent Document 1). In this device, a piezoelectric driving section including a piezoelectric element is biased toward the lens holding member by multiple coil springs and pressed against an axial guide section (receiving member) fixed to the lens holding member. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-097216 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the configuration in which the piezoelectric drive unit is biased toward the receiving member by a plurality of coil springs as described above may result in a complex structure.

[0005] Therefore, it is desirable to provide a lens driving device that can bias the piezoelectric driving portion toward the receiving member with a simpler structure. [Means for solving the problem]

[0006] A lens driving device according to an embodiment of the present invention includes a fixed-side member, a lens holding member capable of holding a lens body, a piezoelectric driving unit provided on one of the fixed-side member and a movable-side member including the lens holding member and having a piezoelectric element extending in a direction intersecting an optical axis direction, a receiving member provided on the other of the movable-side member and the fixed-side member and in contact with the piezoelectric driving unit, and a biasing member that biases the piezoelectric driving unit toward the receiving member, and the lens holding member moves relative to the fixed-side member due to the movement of the piezoelectric element, and the biasing member is a leaf spring member. and has a fixed portion fixed to one of the movable-side member and the fixed-side member, a support portion supporting the piezoelectric drive portion, and an elastically deformable elastic portion provided between the fixed portion and the support portion, wherein the piezoelectric drive portion has a contact member fixed to one surface of the piezoelectric element on the receiving member side, and a flexible wiring board fixed to the other surface of the piezoelectric element, wherein the piezoelectric element and the contact member are fixed with one adhesive, and the flexible wiring board and the support portion are fixed with another adhesive, and the Young's modulus of the other adhesive is smaller than the Young's modulus of the one adhesive. [Effects of the Invention]

[0007] The lens driving device described above can bias the piezoelectric driving portion toward the receiving member with a simpler structure. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 2 is an exploded perspective view of a camera module including a lens driving device. [Figure 2] FIG. 2 is an exploded perspective view of the lens driving device shown in FIG. [Figure 3] FIG. 3 is an exploded perspective view of the piezoelectric driving unit shown in FIG. 2. [Figure 4] FIG. 3 is a top view of the base member shown in FIG. [Figure 5] FIG. 3 is a right side view of the lens holding member shown in FIG. [Figure 6] FIG. 3 is a perspective view of the biasing member shown in FIG. 2. [Figure 7] FIG. 3 is a rear view of the biasing member shown in FIG. 2. [Figure 8] FIG. 3 is a left side view of the urging member shown in FIG. 2. [Figure 9] 3 is a diagram showing the relationship between the frequency of bending vibration caused by the piezoelectric driving unit shown in FIG. 2 and thrust force. [Figure 10] FIG. 10 is a perspective view of another example of the configuration of the lens driving device. [Figure 11] FIG. 11 is an exploded perspective view of the lens driving device shown in FIG. [Figure 12] FIG. 12 is a top view of the base member shown in FIG. [Figure 13] FIG. 12 is a right side view of the lens holding member shown in FIG. [Figure 14] FIG. 12 is a perspective view of the biasing member shown in FIG. [Figure 15] FIG. 12 is a rear view of the biasing member shown in FIG. [Figure 16] FIG. 12 is a left side view of the urging member shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0009] A lens driving device 101 according to an embodiment of the present disclosure will be described below with reference to Figures 1 and 2. Figure 1 is an exploded perspective view of a camera module CM including the lens driving device 101. Figure 2 is an exploded perspective view of the lens driving device 101.

[0010] In FIG. 1, X1 represents one direction of the X axis constituting the three-dimensional Cartesian coordinate system, and X2 represents the other direction of the X axis. Y1 represents one direction of the Y axis constituting the three-dimensional Cartesian coordinate system, and Y2 represents the other direction of the Y axis. Z1 represents one direction of the Z axis constituting the three-dimensional Cartesian coordinate system, and Z2 represents the other direction of the Z axis. In this embodiment, the X1 side of the lens driving device 101 corresponds to the front side (front surface side) of the lens driving device 101, and the X2 side of the lens driving device 101 corresponds to the rear side (rear surface side) of the lens driving device 101. The Y1 side of the lens driving device 101 corresponds to the left side of the lens driving device 101, and the Y2 side of the lens driving device 101 corresponds to the right side of the lens driving device 101. The Z1 side of the lens driving device 101 corresponds to the upper side (subject side) of the lens driving device 101, and the Z2 side of the lens driving device 101 corresponds to the lower side (image sensor side) of the lens driving device 101. The same applies to the other figures.

[0011] The camera module CM is composed of a lens driving device 101, a lens body LS, and an image sensor IS mounted on a substrate (not shown) so as to face the lens body LS. The lens driving device 101 has a substantially rectangular parallelepiped outer shape and is attached to the substrate on which the image sensor IS is mounted.

[0012] In this embodiment, the lens driving device 101 includes a fixed member FB and a movable member MB, as shown in FIGS. 1 and 2. In the illustrated example, the fixed member FB includes a cover member 1, a base member 3, and a guide shaft 4, while the movable member MB includes a lens holding member 2 and a receiving member 5. The movable member MB is configured to be guided in the optical axis direction by a guide mechanism GM. The optical axis direction includes the direction of the optical axis OA of the lens body LS held by the lens holding member 2 and a direction parallel to the optical axis OA. The lens body LS is, for example, a cylindrical lens barrel equipped with at least one lens. The movable member MB is configured to be moved in the optical axis direction by a force generated by a piezoelectric driving unit PD.

[0013] The cover member 1 is configured to cover the upper side of the movable member MB. In this embodiment, the cover member 1 is made by subjecting a metal plate to punching, drawing, and the like. However, the cover member 1 may be made of other materials such as synthetic resin. Specifically, as shown in FIG. 1, the cover member 1 has a flat, rectangular, annular top plate portion 1T. A circular opening 1K is formed in the center of the top plate portion 1T.

[0014] The base member 3 is a member that constitutes a part of the housing HS. In this embodiment, the base member 3 is made of synthetic resin. However, the base member 3 may also be made of metal. The cover member 1 is joined to the base member 3 with an adhesive or the like, and together with the base member 3, constitutes the housing HS.

[0015] As shown in FIG. 2, the lens holding member 2 is configured to hold the lens body LS on the tubular portion 2C with an adhesive. In the example shown in FIG. 2, the lens holding member 2 is made by injection molding a synthetic resin such as liquid crystal polymer (LCP). The lens holding member 2 has a protrusion 2T and a guide portion 2G that protrude radially (outward) from the outer circumferential surface of the cylindrical portion 2C. The protrusion 2T includes a front protrusion 2TF that protrudes forward from the outer circumferential surface of the tubular portion 2C, a left protrusion 2TL that protrudes leftward from the outer circumferential surface of the tubular portion 2C, and a right protrusion 2TR that protrudes rightward from the outer circumferential surface of the tubular portion 2C. The guide portion 2G has a through hole that receives a guide shaft 4.

[0016] The receiving member 5 is a member that receives the driving force generated by the piezoelectric driver PD. In this embodiment, the receiving member 5 is a cylindrical member that is made of a metal such as titanium copper or stainless steel and extends in the optical axis direction. The receiving member 5 may be made of other metals, and the other metals may be either magnetic or non-magnetic. In the example shown in FIG. 2, the receiving member 5 is fitted and fixed in a U-shaped groove 2U formed in the front protrusion 2TF of the lens holding member 2, and is configured to be able to move in the optical axis direction together with the lens holding member 2.

[0017] The biasing member 6 is configured to be able to bias the piezoelectric driver PD toward the receiving member 5. In the example shown in FIG. 2, the biasing member 6 is configured as a leaf spring member formed by pressing a titanium copper metal plate using a progressive die. The metal plate may be formed of other metals such as stainless steel. In the example shown in FIG. 2, both ends of the biasing member 6 are fixed to the inner circumferential surface of the base member 3, and the biasing member 6 is configured to be able to press the piezoelectric driver PD toward the receiving member 5 fixed to the lens holding member 2.

[0018] The piezoelectric drive unit PD is configured to be able to move the lens holding member 2 along the optical axis direction. In this embodiment, the piezoelectric drive unit PD is an example of a friction drive unit that uses the drive system disclosed in U.S. Patent No. 7,786,648, and includes a piezoelectric element 8, a contact member 9, and a flexible wiring board 10. The piezoelectric drive unit PD is configured to be biased inward (in the direction approaching the optical axis OA) by a biasing member 6 and pressed against the receiving member 5.

[0019] The piezoelectric element 8 is configured to be able to realize bending vibration in response to an applied voltage. In this embodiment, as shown in Fig. 3, the piezoelectric element 8 extends in the Y-axis direction orthogonal to the optical axis direction (the direction perpendicular to the optical axis OA), and is configured to be able to realize bending vibration having two nodes (nodes ND). In other words, when bending vibration is generated, the two nodes ND hardly vibrate.

[0020] FIG. 3 is an exploded perspective view of the piezoelectric driver PD supported by the biasing member 6. For clarity, in FIG. 3, cross patterns are applied to the positions of the nodes ND of the piezoelectric element 8 and the positions AP of the flexible wiring substrate 10 corresponding to the nodes ND. The positions of the nodes ND of the piezoelectric element 8 include the positions of a first node ND1 and a second node ND2. The positions of the nodes ND correspond to positions that are a predetermined distance from the end of the piezoelectric element 8 in the Y-axis direction. The predetermined distance is, for example, approximately one-fourth of the overall length of the piezoelectric element 8. Specifically, the position of the first node ND1 is located at a distance D1 from the left end LE of the piezoelectric element 8, and the position of the second node ND2 is located at a distance D2 from the right end RE of the piezoelectric element 8. Both the distance D1 and the distance D2 are approximately one-fourth of the overall length of the piezoelectric element 8.

[0021] In the example shown in FIG. 3, the piezoelectric element 8 has a two-layer structure stacked in the X-axis direction, consisting of a first layer that realizes a first bending vibration on an imaginary plane parallel to the XY plane and a second layer that realizes a second bending vibration on an imaginary plane parallel to the YZ plane. The piezoelectric driver PD can cause the piezoelectric element 8 to perform bending vibration (circular motion) so that the path traced by the midpoint of the piezoelectric element 8 forms a circular orbit centered on the rotation axis 8X when viewed from the left side, when voltage is applied to the piezoelectric element portion of the first layer and the piezoelectric element portion of the second layer at appropriate timings. In other words, the piezoelectric element 8 can achieve circular motion (circular motion) with its midpoint tracing a circular orbit. Note that in the example shown in FIG. 3, the rotation axis 8X is parallel to the Y-axis. Furthermore, by applying voltage at appropriate timings, the piezoelectric driver PD can switch the movement direction (rotation direction) of the midpoint tracing the circular orbit between clockwise and counterclockwise as viewed from the Y1 side. By switching the rotation direction, the piezoelectric driver PD can switch the movement direction along the optical axis of the lens holding member 2. Note that the circle (circular orbit) described by the midpoint of the piezoelectric element 8 does not have to be a perfect circle (true circle), as long as it is approximately circular.

[0022] 3, the arrows drawn around the piezoelectric element 8 represent the bending vibration of the piezoelectric element 8 (circular motion in which the piezoelectric element 8 rotates clockwise around the rotation axis 8X as viewed from the Y1 side while bending). In this case, the movable member MB, including the receiving member 5 in contact with the contact member 9 of the piezoelectric drive unit PD, moves upward (in the Z1 direction). Although not indicated by an arrow, the piezoelectric element 8 can also rotate counterclockwise around the rotation axis 8X as viewed from the Y1 side while bending. In this case, the movable member MB, including the receiving member 5 in contact with the contact member 9 of the piezoelectric drive unit PD, moves downward (in the Z2 direction).

[0023] That is, the lens holding member 2 to which the receiving member 5 is attached is moved upward (in the Z1 direction) when the rotation direction of the midpoint of the piezoelectric element 8 is clockwise as viewed from the left side, and is moved downward (in the Z2 direction) when the rotation direction of the midpoint of the piezoelectric element 8 is counterclockwise. In the example shown in Fig. 3, the midpoint of the piezoelectric element 8 is a point corresponding to the peak of the amplitude of the first bending vibration (a point corresponding to the antinode of the first bending vibration) and also a point corresponding to the peak of the amplitude of the second bending vibration (a point corresponding to the antinode of the second bending vibration).

[0024] The contact member 9 is attached to the piezoelectric element 8 and configured to come into contact with the receiving member 5. In this embodiment, the contact member 9 is bonded to the inner surface of the piezoelectric element 8 with a first adhesive AD1 so as to cover the entire inner surface (X2 side, which is the side facing the optical axis OA) of the piezoelectric element 8. The contact member 9 is formed of a metal such as titanium copper or stainless steel, and configured with an appropriate thickness so that it can perform bending vibration (circular motion) in response to the bending vibration (circular motion) of the piezoelectric element 8. In the example shown in FIG. 3, the contact member 9 is a friction plate made of stainless steel. The contact member 9 extends in the Y-axis direction, which is the same as the extension direction of the piezoelectric element 8. The contact member 9 is configured to come into contact with the receiving member 5 at a central portion in the extension direction. Specifically, the contact member 9 is configured to come into contact with the receiving member 5 at a portion where the amplitude of the bending vibration (circular motion) is maximum (a portion corresponding to the antinode of the bending vibration). In the example shown in FIG. 3, the surface 9S of the contact member 9 on the side (X2 side) that comes into contact with the receiving member 5 is a convex curved surface that is convex toward the X2 side. That is, the surface 9S is configured to form a surface having one convex portion. However, the surface 9S may be configured to form a surface having two or more convex portions (for example, see the surface 9Sa indicated by the dashed line in the lower diagram of FIG. 8).

[0025] The reason for bringing the metal receiving member 5 and the metal contact member 9 into contact is to prevent wear of the lens holding member 2 due to contact between the synthetic resin lens holding member 2 and the metal contact member 9. Note that, as long as contact between the receiving member 5 and the contact member 9 can be obtained, the length dimension of the contact member 9 in the Y-axis direction does not have to be the same as the length dimension of the piezoelectric element 8 in the Y-axis direction. For example, the length dimension of the contact member 9 in the Y-axis direction may be smaller than the length dimension of the piezoelectric element 8 in the Y-axis direction.

[0026] The flexible wiring board 10 is a board including a conductive pattern (not shown), and is configured to be able to electrically connect an external voltage supply source (control circuit) and the piezoelectric element 8. In this embodiment, the flexible wiring board 10 is configured to be able to apply a voltage to the piezoelectric element 8. Specifically, the flexible wiring board 10 includes a joint 10B that is joined to the piezoelectric element 8, and an extension 10E that extends outward from the joint 10B.

[0027] As shown in FIG. 3, the piezoelectric element 8 is bonded to the inner surface (X2 side, which is the side facing the optical axis OA) of the flexible wiring board 10 by a second adhesive AD2. In the illustrated example, the second adhesive AD2 is an anisotropic conductive film. However, the second adhesive AD2 may be an isotropic conductive film, an anisotropic conductive adhesive, or an isotropic conductive adhesive. In the illustrated example, the piezoelectric element 8 has electrodes ED at each of the four corners of its outer surface (X1 side). The electrodes ED of the piezoelectric element 8 are bonded to a conductive portion (conductive pattern) formed on the inner surface of the flexible wiring board 10 via the second adhesive AD2.

[0028] The piezoelectric driver PD is configured to be biased inward (toward the optical axis OA) by a biasing member 6 fixed to the base member 3, and pressed against the receiving member 5. In the example shown in Fig. 3, the biasing member 6 is configured to come into contact with the outer surface (the X1 side, which is the side farther from the optical axis OA) of the flexible wiring board 10 at positions AP corresponding to two nodes ND formed during bending vibration of the piezoelectric element 8. The biasing member 6 and the flexible wiring board 10 are bonded together by, for example, a third adhesive AD3.

[0029] As shown in FIG. 2, the base member 3 has a generally rectangular cylindrical outer wall portion 3A that defines the storage section 3S, and a flat, rectangular, annular bottom plate portion 3B. Specifically, the outer wall portion 3A includes a first side plate portion 3A1 to a fourth side plate portion 3A4. The first side plate portion 3A1 and the third side plate portion 3A3 face each other, and the second side plate portion 3A2 and the fourth side plate portion 3A4 face each other. The second side plate portion 3A2 and the fourth side plate portion 3A4 extend perpendicular to the first side plate portion 3A1 and the third side plate portion 3A3. That is, the first side plate portion 3A1 and the third side plate portion 3A3 extend perpendicular to the second side plate portion 3A2 and the fourth side plate portion 3A4.

[0030] A pair of restricting portions 3N that restrict movement of the lens holding member 2 is formed on the inner surface of each of the second side plate 3A2 and the fourth side plate 3A4. A groove 3G that receives the protrusion 2T of the lens holding member 2 is formed between the pair of restricting portions 3N. Specifically, a pair of left-side restricting portions 3NL is formed on the inner surface of the second side plate 3A2, and a pair of right-side restricting portions 3NR is formed on the inner surface of the fourth side plate 3A4. A left-side groove 3GL that receives the left-side protrusion 2TL of the lens holding member 2 is formed between the pair of left-side restricting portions 3NL, and a right-side groove 3GR that receives the right-side protrusion 2TR of the lens holding member 2 is formed between the pair of right-side restricting portions 3NR.

[0031] An upwardly protruding columnar portion 3P is formed at each of the four corners of the bottom plate portion 3B. An upwardly protruding cylindrical adhesive reservoir portion 3C is provided on the top surface of the bottom plate portion 3B, and a circular opening 3K is formed in the center of the bottom plate portion 3B.

[0032] Specifically, the columnar portion 3P includes a left rear columnar portion 3PBL, a right rear columnar portion 3PBR, a left front columnar portion 3PFL, and a right front columnar portion 3PFR. A cylindrical connecting pin 3T protruding upward is formed on the top surface of each of the left rear columnar portion 3PBL, the right rear columnar portion 3PBR, the left front columnar portion 3PFL, and the right front columnar portion 3PFR. The four connecting pins 3T are formed to fit into four circular through-holes 1H formed in the four corners of the cover member 1. In the illustrated example, the cover member 1 and the base member 3 are joined by applying an adhesive to the through-holes 1H and the connecting pins 3T with the connecting pins 3T fitted into the through-holes 1H as shown in FIG. 1 .

[0033] The left front columnar portion 3PFL and the right front columnar portion 3PFR are formed with clamping portions 3W. The clamping portions 3W are slit-shaped grooves configured to be able to clamp the biasing member 6, and include a left clamping portion 3WL and a right clamping portion 3WR. In the example shown in Fig. 2, the left clamping portion 3WL is formed on the right side surface of the left front columnar portion 3PFL, and the right clamping portion 3WR is formed on the left side surface of the right front columnar portion 3PFR.

[0034] The guide mechanism GM is configured to guide the lens holder 2 movably in the optical axis direction relative to the fixed-side member FB. In this embodiment, the guide mechanism GM includes a combination of a guide portion 2G formed on the outer peripheral surface of the cylindrical portion 2C of the lens holder 2 and a guide shaft 4. Note that the combination of the left protrusion 2TL formed on the cylindrical portion 2C of the lens holder 2 and the left groove 3GL formed on the second side plate 3A2 of the base member 3, or the combination of the right protrusion 2TR formed on the cylindrical portion 2C of the lens holder 2 and the right groove 3GR formed on the fourth side plate 3A4 of the base member 3, may be configured to function as part of the guide mechanism GM. Alternatively, the combination of the left protrusion 2TL and the left groove 3GL and the combination of the right protrusion 2TR and the right groove 3GR may function as the guide mechanism GM. In this case, the combination of the guide portion 2G and the guide shaft 4 may be omitted. This is because if each of the three combinations functions as the guide mechanism GM, poor dimensional accuracy of the parts may prevent smooth guidance of the lens holder 2. However, each of the three combinations may be configured to function as the guide mechanism GM.

[0035] In the illustrated example, the guide mechanism GM includes two guide mechanisms (a left guide mechanism GML and a right guide mechanism GMR) that are arranged to face each other across the lens holder 2 on either side (the Y1 side and the Y2 side) of a line segment L1 that passes through the optical axis OA and the center of the receiving member 5, as shown in the lower diagram of FIG. 4 . FIG. 4 is a top view of the base member 3. Specifically, the upper diagram of FIG. 4 is a top view of the base member 3 without the lens holder 2, guide shaft 4, receiving member 5, biasing member 6, and piezoelectric drive unit PD attached, and the lower diagram of FIG. 4 is a top view of the base member 3 with the lens holder 2, guide shaft 4, receiving member 5, biasing member 6, and piezoelectric drive unit PD attached. Note that, for clarity, a dot pattern is applied to the base member 3 in the upper diagram of FIG. 4 , and a dot pattern is applied to the lens holder 2 in the lower diagram of FIG. 4 .

[0036] As shown in the upper diagram of FIG. 4, the guide shaft 4 is adhesively fixed to the base member 3 with an adhesive applied to the inside of a cylindrical adhesive reservoir 3C formed in the bottom plate 3B of the base member 3. Specifically, the guide shaft 4 is fixed to the base member 3 with the adhesive, with its lower end fitted into a circular recess 3Q formed in the inner bottom surface of the adhesive reservoir 3C. As shown in the lower diagram of FIG. 4, the guide shaft 4 is inserted into a through-hole 2H that has a rounded rectangular shape in a top view and is formed in the guide portion 2G of the lens holding member 2. The rounded rectangle has two sides of equal length and two semicircles, and the radius of the semicircles is approximately the same as the radius of the guide shaft 4. The sides of the rounded rectangle are parallel to a line segment L2 that passes through the optical axis OA and the center of the guide shaft 4.

[0037] In the illustrated example, the guide portion 2G is configured so that the length dimension HT1 in the optical axis direction is smaller than the length dimension HT2 of the cylindrical portion of the guide shaft 4, as shown in FIG.

[0038] Fig. 5 is a right side view of the lens holder 2, guide shaft 4, receiving member 5, urging member 6, and piezoelectric driver PD. Specifically, Fig. 5 shows the positional relationship between the lens holder 2 and the guide shaft 4, receiving member 5, urging member 6, and piezoelectric driver PD when the lens holder 2 is in the lowest position. Note that in Fig. 5, a dot pattern is added to the lens holder 2 for clarity.

[0039] The lens holding member 2 is configured so that, when the lens holding member 2 is at its lowest position, three lower stopper portions 2SD provided at the lower end of the cylindrical portion 2C come into contact with three protrusions 3M (see FIG. 2) provided so as to protrude upward from the upper surface of the bottom plate portion 3B of the base member 3. Furthermore, when the lens holding member 2 is at its highest position, three upper stopper portions 2SU provided at the upper end of the cylindrical portion 2C come into contact with three protrusions 1M (see FIG. 2) provided so as to protrude downward from the lower surface of the top plate portion 1T of the cover member 1.

[0040] 5, the guide portion 2G is configured so that the length dimension HT1 in the optical axis direction is greater than the length dimension HT3. The length dimension HT3 is the distance between the contact point CP between the receiving member 5 and the contact member 9 and the lower end of the cylindrical portion of the receiving member 5 when the lens holding member 2 is at its lowest position.

[0041] With this configuration, the guide portion 2G can keep at least a portion of the cylindrical portion of the guide shaft 4 within the through hole 2H even when the lens holding member 2 reaches its highest position, thereby stabilizing the movement of the lens holding member 2 over the entire range of movement of the lens holding member 2 in the optical axis direction.

[0042] As shown in the lower diagram of Figure 4, the receiving member 5 and at least one of the guide mechanisms GM (the right guide mechanism GMR) are arranged to face each other on both sides (the X1 side and the X2 side) of a line segment L3 that is perpendicular to the line segment L1 and passes through the optical axis OA, sandwiching the lens holding member 2. With this arrangement, the guide mechanism GM can stably move the lens holding member 2 along the optical axis direction.

[0043] In the above-described lens driving device 101, the piezoelectric element 8 is connected to an external voltage supply source (control circuit) via the flexible wiring board 10. When a voltage is applied to the piezoelectric element 8, the piezoelectric element 8 performs a first bending vibration and a second bending vibration, generating a force that moves the lens holding member 2 along the optical axis direction. This force is a frictional force caused by contact between the receiving member 5 attached to the lens holding member 2 and the contact member 9 bonded to the piezoelectric element 8.

[0044] The lens driving device 101 utilizes this force to move the lens holding member 2 along the optical axis direction on the Z1 side (subject side) of the image sensor IS, thereby realizing an autofocus function. Specifically, the lens driving device 101 moves the lens holding member 2 away from the image sensor IS to enable macro photography, and moves the lens holding member 2 toward the image sensor IS to enable infinity photography.

[0045] Next, the biasing member 6 will be described in detail with reference to FIGS. 6 to 8. FIG. 6 is a perspective view of the biasing member 6. Specifically, the upper view of FIG. 6 is a perspective view of the biasing member 6 with the piezoelectric drive unit PD removed. The lower view of FIG. 6 is a perspective view of the biasing member 6 with the piezoelectric drive unit PD attached. FIG. 7 is a rear view of the biasing member 6. Specifically, the upper view of FIG. 7 is a rear view of the biasing member 6 with the piezoelectric drive unit PD removed. The lower view of FIG. 7 is a rear view of the biasing member 6 with the piezoelectric drive unit PD attached. FIG. 8 is a left side view of the biasing member 6. Specifically, the upper view of FIG. 8 is a left side view of the biasing member 6 with the piezoelectric drive unit PD removed. The lower view of FIG. 8 is a left side view of the biasing member 6 with the piezoelectric drive unit PD attached. Note that in the lower views of FIGS. 6 to 8, a dot pattern is applied to the biasing member 6 for clarity.

[0046] In this embodiment, the biasing member 6 is configured by a leaf spring member formed from a single metal plate. Specifically, as shown in the upper views of each of FIGS. 6 to 8, the biasing member 6 has a fixed portion 6A fixed to the base member 3, a support portion 6S supporting the piezoelectric driver PD, an elastically deformable elastic deformation portion 6E provided between the fixed portion 6A and the support portion 6S, and a bent portion 6N bent in an L-shape from the support portion 6S and protruding toward the side where the lens holding member 2 is located (X2 side). The fixed portion 6A is a portion that is clamped by the clamping portion 3W of the base member 3. The fixation of the fixed portion 6A to the base member 3 may be reinforced with an adhesive in addition to being clamped by the clamping portion 3W.

[0047] Specifically, the fixed portion 6A includes a left fixed portion 6AL and a right fixed portion 6AR, and the support portion 6S includes a base portion 6SC, a left support portion 6SL, and a right support portion 6SR. The elastic deformation portion 6E includes a left elastic deformation portion 6EL provided between the left fixed portion 6AL and the left support portion 6SL, and a right elastic deformation portion 6ER provided between the right fixed portion 6AR and the right support portion 6SR. The bending portion 6N includes a left bending portion 6NL extending rearward (in the X2 direction) from the left support portion 6SL, and a right bending portion 6NR extending rearward (in the X2 direction) from the right support portion 6SR. The left bending portion 6NL includes an upper-left bending portion 6NUL extending rearward (in the X2 direction) from the upper end of the left support portion 6SL, and a lower-left bending portion 6NDL extending rearward (in the X2 direction) from the lower end of the left support portion 6SL. The right bent portion 6NR includes an upper right bent portion 6NUR extending rearward (in the X2 direction) from the upper end of the right support portion 6SR, and a lower right bent portion 6NDR extending rearward (in the X2 direction) from the lower end of the right support portion 6SR.

[0048] The base 6SC includes four protruding portions 6P protruding rearward (in the X2 direction) and having circular end faces, and one protruding portion 6Q protruding rearward (in the X2 direction) and having a rounded rectangular end face. In the illustrated example, the protruding portions 6Q are drawn beads formed by drawing. The protruding portion 6Q may be omitted. In the illustrated example, the four protruding portions 6P and the one protruding portion 6Q are formed by drawing, doweling, or half-blanking, rather than bending, and are formed so that their end faces are flat. Therefore, as shown in FIG. 3, recesses corresponding to the four protruding portions 6P and the one protruding portion 6Q are formed on the front surface (the surface on the X1 side) of the base 6SC. Note that the protruding portion 6Q may be formed to protrude forward (in the X1 direction). In this case, recesses corresponding to the protruding portions 6Q are formed on the rear surface (the surface on the X2 side) of the base 6SC.

[0049] Although the end face of the protrusion 6P has a circular shape, it may have other shapes, such as an ellipse or a rounded rectangle. The same applies to the end face of the protrusion 6Q. Specifically, as shown in the upper diagram of FIG. 7 , the protrusion 6Q extends along the extension direction (Y-axis direction) of the piezoelectric element 8 and is formed to have a width WD2 that is larger than the width WD1, which is the distance between the left bent portion 6NL and the right bent portion 6NR. The protrusion 6P includes an upper-left protrusion 6PUL arranged above the left end of the protrusion 6Q, a lower-left protrusion 6PDL arranged below the left end of the protrusion 6Q, an upper-right protrusion 6PUR arranged above the right end of the protrusion 6Q, and a lower-right protrusion 6PDR arranged below the right end of the protrusion 6Q. Note that, hereinafter, the upper-left protrusion 6PUL and the lower-left protrusion 6PDL may be referred to as the left protrusion 6PL, and the upper-right protrusion 6PUR and the lower-right protrusion 6PDR may be referred to as the right protrusion 6PR. Furthermore, the positions at which the convex portions 6P are arranged are preferably positions corresponding to the nodes ND of the piezoelectric element 8, and specifically include a first position PS1 and a second position PS2 arranged spaced apart from each other in the extension direction (Y-axis direction) of the piezoelectric element 8. The upper left convex portion 6PUL and the lower left convex portion 6PDL are arranged at the first position PS1, and the upper right convex portion 6PUR and the lower right convex portion 6PDR are arranged at the second position PS2.

[0050] The elastically deforming portion 6E may have a wide portion 6W that suppresses twisting of the biasing member 6 caused by bending vibration of the piezoelectric element 8. In the illustrated example, the wide portion 6W is formed to have a vertical width WT2 that is larger than the vertical width WT1 of the other portions of the elastically deforming portion 6E, as shown in the upper diagram of FIG. 7 . The wide portion 6W also includes a left wide portion 6WL extending leftward (in the Y1 direction) from the left support portion 6SL and a right wide portion 6WR extending rightward from the right support portion 6SR. A through-hole 6H is also formed in the wide portion 6W. Specifically, a left wide portion 6HL is formed in the left wide portion 6WL, and a right wide portion 6HR is formed in the right wide portion 6WR. More specifically, the left wide portion 6HL includes an upper-left through-hole 6HUL and a lower-left through-hole 6HDL, and the right wide portion 6HR includes an upper-right through-hole 6HUR and a lower-right through-hole 6HDR. Therefore, the left wide portion 6WL is divided into three connecting portions (upper left connecting portion 6WUL, left central connecting portion 6WML, and lower left connecting portion 6WDL), and the right wide portion 6WR is divided into three connecting portions (upper right connecting portion 6WUR, right central connecting portion 6WMR, and lower right connecting portion 6WDR).

[0051] In the illustrated example, the wide portion 6W is formed so that the width WD3, which is the distance between the left end of the left wide portion 6WL and the right end of the right wide portion 6WR, is greater than the width WD4 of the piezoelectric drive portion PD (piezoelectric element 8), as shown in the lower diagram of Fig. 7. Note that in the illustrated example, the support portion 6S is formed so that the width WD5, which is the distance between the left end of the left support portion 6SL and the right end of the right support portion 6SR, is smaller than the width WD4 of the piezoelectric drive portion PD (piezoelectric element 8), as shown in the lower diagram of Fig. 7.

[0052] As shown in the lower diagrams of Figures 6 to 8, the piezoelectric driver PD is arranged so that its left portion is located between the upper-left bent portion 6NUL and the lower-left bent portion 6NDL, and its right portion is located between the upper-right bent portion 6NUR and the lower-right bent portion 6NDR. Specifically, as shown in the lower diagram of Figure 8, the piezoelectric driver PD is arranged so that the bottom piece DE of the upper-left bent portion 6NUL faces the top edge portion UG of the piezoelectric driver PD (the top surface of the piezoelectric element 8) without contact, and so that the top piece UE of the lower-left bent portion 6NDL faces the bottom edge portion DG of the piezoelectric driver PD (the bottom surface of the piezoelectric element 8) without contact. The same applies to the relationship between the bottom end of the upper-right bent portion 6NUR and the top edge portion UG of the piezoelectric driver PD (the top surface of the piezoelectric element 8), and the relationship between the top end of the lower-right bent portion 6NDR and the bottom edge portion DG of the piezoelectric driver PD (the bottom surface of the piezoelectric element 8). In this way, the bent portion 6N and the piezoelectric element 8 are combined so as to face each other without contacting each other.

[0053] 8, the piezoelectric driving unit PD is attached to the biasing member 6 so that the front surface (X1-side surface) of the joint portion 10B of the flexible wiring board 10 is adhesively fixed to the end surfaces of the upper-left convex portion 6PUL and the lower-left convex portion 6PDL with a third adhesive AD3 (see the upper diagram of FIG. 7). On the other hand, as shown in the lower diagram of FIG. 8, the piezoelectric driving unit PD is attached to the biasing member 6 so that the front surface (X1-side surface) of the joint portion 10B of the flexible wiring board 10 does not come into contact with the protrusion 6Q, i.e., so that a gap GP is formed between the front surface (X1-side surface) of the joint portion 10B of the flexible wiring board 10 and the end surface of the protrusion 6Q. Specifically, as shown in the upper diagram of FIG. 8, the protrusion 6P is formed to protrude rearward from the rear surface of the support portion 6S by a protrusion height PT1, and the protrusion 6Q is formed to protrude rearward from the rear surface of the support portion 6S by a protrusion height PT2 (<protrusion height PT1). Since the protrusions 6P are formed by drawing, the protrusion height PT1 can be made smaller than when they are formed by bending.

[0054] The third adhesive AD3 is an adhesive for bonding and fixing the joint portion 10B of the flexible wiring board 10 and the support portion 6S of the biasing member 6. Specifically, the third adhesive AD3 is applied to each of the four protrusions 6P as shown in the upper diagram of FIG. 7 in order to bond and fix positions AP (see FIG. 3) in the joint portion 10B corresponding to the nodes ND of the piezoelectric element 8 to the four protrusions 6P on the base portion 6SC of the support portion 6S. In the illustrated example, the third adhesive AD3 is applied so as to cover the entire end face and entire circumferential surface of each of the four protrusions 6P, but not to adhere to the protrusions 6Q.

[0055] In this embodiment, the third adhesive AD3 is an ultraviolet curing adhesive, but the third adhesive AD3 may be another type of adhesive, such as a moisture curing or heat curing adhesive.

[0056] As shown in the lower diagram of FIG. 8, the left convex portion 6PL is formed so that its height dimension HT11 in the optical axis direction is greater than the height dimension HT12 of the piezoelectric driver PD in the optical axis direction. In the illustrated example, the height dimension HT11 is the distance between the upper end of the upper-left convex portion 6PUL, which has a diameter DM1, and the lower end of the lower-left convex portion 6PDL, which has a diameter DM2. The upper-left convex portion 6PUL and the lower-left convex portion 6PDL are spaced apart by a distance DS1 in the optical axis direction, and the diameters DM1 and DM2 are the same. That is, the left convex portion 6PL is formed so that it protrudes upward by a distance DS2 from the upper edge portion UG of the piezoelectric driver PD and downward by a distance DS3 from the lower edge portion DG of the piezoelectric driver PD in the optical axis direction.

[0057] In the above-described embodiment, the left protrusion 6PL is configured by a combination of an upper-left protrusion 6PUL and a lower-left protrusion 6PDL, but it may be configured by a single elongated protrusion extending in the Z-axis direction. Even in this case, the left protrusion 6PL is formed so that the height dimension HT11, which is the distance between its upper end and lower end in the optical axis direction, is greater than the height dimension HT12 of the piezoelectric driver PD in the optical axis direction. The same is true for the right protrusion 6PR.

[0058] In this way, the protrusions 6P are formed so as to protrude outward from both ends of the piezoelectric driver PD in the optical axis direction, and therefore can reliably support both ends of the joint 10B of the flexible wiring board 10 in the optical axis direction. Therefore, the protrusions 6P support the joint 10B at the position AP (see FIG. 3) corresponding to the node ND of the piezoelectric element 8, and can prevent the joint 10B from peeling off from the end face of the protrusion 6P due to bending vibration of the piezoelectric element 8, causing the joint 10B to tilt relative to the end face of the protrusion 6P.

[0059] Next, the relationship between the frequency of bending vibrations generated by the piezoelectric driver PD and thrust force will be described with reference to FIG. 9. FIG. 9 is a diagram showing the relationship between the frequency of bending vibrations generated by the piezoelectric driver PD and thrust force. The thrust force generated by the piezoelectric driver PD is a force generated by the piezoelectric driver PD to move the lens holding member 2 along the optical axis direction. Specifically, the upper diagram in FIG. 9 is a table showing the characteristics of adhesives used in the piezoelectric driver PD according to the first and second embodiments of the lens driving device 101. The center diagram in FIG. 9 is a graph showing the relationship between the frequency of bending vibrations generated by the piezoelectric driver PD according to the first embodiment and thrust force. The bottom diagram in FIG. 9 is a graph showing the relationship between the frequency of bending vibrations generated by the piezoelectric driver PD according to the second embodiment and thrust force.

[0060] The first and second embodiments differ from each other in that the first adhesive AD1 bonding the piezoelectric element 8 to the contact member 9, the second adhesive AD2 bonding the piezoelectric element 8 to the flexible wiring board 10, and the third adhesive AD3 bonding the flexible wiring board 10 to the biasing member 6 have different properties. In the illustrated examples, the first adhesive AD1 is an epoxy adhesive and the second adhesive AD2 is an acrylic adhesive in the first embodiment and the second embodiment. The third adhesive AD3 is an acrylic adhesive in the first embodiment and a silicone adhesive in the second embodiment.

[0061] 9, the glass transition temperature (40°C) of the first adhesive AD1 in the first example is lower than the glass transition temperature (150°C) of the first adhesive AD1 in the second example, and the Young's modulus (4.5 GPa) of the first adhesive AD1 in the first example is higher than the Young's modulus (4.4 GPa) of the first adhesive AD1 in the second example. In addition, the glass transition temperature (-6°C) of the third adhesive AD3 in the first example is higher than the glass transition temperature (-65°C) of the third adhesive AD3 in the second example, and the Young's modulus (0.003 GPa) of the third adhesive AD3 in the first example is higher than the Young's modulus (0.0004 GPa) of the third adhesive AD3 in the second example. The glass transition temperature (62°C) of the second adhesive AD2 in the first embodiment is the same as the glass transition temperature (62°C) of the second adhesive AD2 in the second embodiment, and the Young's modulus (0.1 GPa) of the second adhesive AD2 in the first embodiment is the same as the Young's modulus (0.1 GPa) of the second adhesive AD2 in the second embodiment.

[0062] That is, in both the first and second examples, the Young's modulus of the second adhesive AD2 (0.1 GPa) is smaller than the Young's modulus of the first adhesive AD1 (4.5 GPa or 4.4 GPa) and larger than the Young's modulus of the third adhesive AD3 (0.003 GPa or 0.0004 GPa). That is, in both the first and second examples, the second adhesive AD2 is softer than the first adhesive AD1 and harder than the third adhesive AD3. In this embodiment, it is desirable that the Young's modulus of the first adhesive AD1 is 1 to 9 GPa, the Young's modulus of the second adhesive AD2 is 0.01 to 0.9 GPa, and the Young's modulus of the third adhesive AD3 is 0.0001 to 0.9 GPa.

[0063] The glass transition temperatures differ between Example 1 and Example 2. Specifically, in Example 1, the glass transition temperature of the first adhesive AD1 (40°C) is lower than the glass transition temperature of the second adhesive AD2 (62°C) and higher than the glass transition temperature of the third adhesive AD3 (-6°C). On the other hand, in Example 2, the glass transition temperature of the second adhesive AD2 (62°C) is lower than the glass transition temperature of the first adhesive AD1 (150°C) and higher than the glass transition temperature of the third adhesive AD3 (-65°C).

[0064] In the first embodiment, the glass transition temperatures of the first adhesive AD1 (40°C) and the third adhesive AD3 (-6°C) are within the operating temperature range of the lens driving device 101, and the glass transition temperature of the second adhesive AD2 (62°C) is higher than the upper limit of the operating temperature range. The operating temperature range of the lens driving device 101 is, for example, -10°C to 60°C. In the second embodiment, the first adhesive AD1, the second adhesive AD2, and the third adhesive AD3 are all outside the operating temperature range. Specifically, in the second embodiment, the glass transition temperatures of the first adhesive AD1 (150°C) and the second adhesive AD2 (62°C) are higher than the upper limit of the operating temperature range (60°C), and the glass transition temperature of the third adhesive AD3 (-65°C) is lower than the lower limit of the operating temperature range (-10°C). Therefore, in the second embodiment, the hardness of each of the first adhesive AD1 to third adhesive AD3 does not change significantly as long as the lens driving device 101 is used within the operating temperature range. Therefore, compared to the first embodiment, the second embodiment has the advantage that the characteristics of the piezoelectric driving unit PD are less likely to change even when the ambient temperature (operating temperature) changes.

[0065] Next, the relationship between the frequency of bending vibration generated by the piezoelectric actuator PD and thrust will be explained with reference to the graphs in the center and bottom diagrams of Figure 9. In both the center and bottom diagrams of Figure 9, the vertical axis represents thrust [mN] and the horizontal axis represents frequency [Hz], and the scale is the same. In both the center and bottom diagrams of Figure 9, the solid line represents the relationship when the operating temperature is 22°C, the dashed line represents the relationship when the operating temperature is 60°C, and the dash-dot line represents the relationship when the operating temperature is -10°C.

[0066] In the central diagram of Figure 9, which shows the relationship between the frequency of bending vibration by the piezoelectric drive unit PD of the first embodiment and thrust, at frequency fa, the thrust when the operating temperature is 22°C and the thrust when the operating temperature is -10°C are approximately the same value n1, and the difference with the thrust when the operating temperature is 60°C is also approximately n1.

[0067] 9, which shows the relationship between the frequency of bending vibration and thrust force generated by the piezoelectric driver PD according to the second embodiment, at frequency fb, the thrust force when the operating temperature is 22° C. and the thrust force when the operating temperature is 60° C. are approximately the same value n2, and the difference with the thrust force when the operating temperature is -10° C. is approximately n1. Note that value n2 is twice as large as value n1.

[0068] In other words, assuming that the operating temperature range is from -10°C to 60°C and that a configuration is used in which bending vibration of the piezoelectric drive unit PD is achieved at a single frequency, the piezoelectric drive unit PD of the second embodiment has the effect of being able to achieve a greater thrust than the piezoelectric drive unit PD of the first embodiment, while maintaining the magnitude of thrust fluctuation in response to changes in operating temperature at the same level as that of the piezoelectric drive unit PD of the first embodiment.

[0069] Next, with reference to FIGS. 10 to 13, a lens driving device 101V, which is another configuration example of the lens driving device 101 according to the embodiment of the present disclosure, will be described. FIG. 10 is a perspective view of the lens driving device 101V. FIG. 11 is an exploded perspective view of the lens driving device 101V. FIG. 12 is a top view of the base member 3 constituting the lens driving device 101V. Specifically, the upper view of FIG. 12 is a top view of the base member 3 in a state where the lens holding member 2, guide shaft 4, receiving member 5V, biasing member 6, and piezoelectric driving unit PD are not attached, and the lower view of FIG. 12 is a top view of the base member 3 in a state where the lens holding member 2, guide shaft 4, receiving member 5V, biasing member 6, and piezoelectric driving unit PD are attached. Note that, for clarity, a dot pattern is applied to the base member 3 in the upper view of FIG. 12, and a dot pattern is applied to the lens holding member 2 in the lower view of FIG. 12. Figure 13 is a right side view of the lens holder 2, guide shaft 4, receiving member 5V, urging member 6, and piezoelectric driver PD. Specifically, Figure 13 shows the positional relationship between the lens holder 2 and the guide shaft 4, receiving member 5V, urging member 6, and piezoelectric driver PD when the lens holder 2 is in the lowest position. Note that a dot pattern is added to the lens holder 2 in Figure 13 for clarity.

[0070] The lens driving device 101V differs from the lens driving device 101, in that the piezoelectric driving unit PD is provided on the movable-side member MB (lens holding member 2), in that the piezoelectric driving unit PD is provided on the fixed-side member FB (base member 3). In other respects, the lens driving device 101V is the same as the lens driving device 101. Therefore, in the following, a description of common parts will be omitted, and differences will be described in detail. Furthermore, the same reference symbols are used for the same or corresponding parts in the lens driving device 101 and the lens driving device 101V.

[0071] Specifically, the lens driving device 101V differs from the lens driving device 101 having the receiving member 5 fixed to the lens holding member 2 in that the lens driving device 101V has a receiving member 5V fixed to the base member 3.

[0072] The receiving member 5V is a fixed member FB that receives the driving force generated by the piezoelectric driver PD. In the illustrated example, the receiving member 5V is a columnar member made of titanium copper and extending in the optical axis direction. Its upper end is fixed to the top plate 1T of the cover member 1 and its lower end is fixed to the bottom plate 3B of the base member 3. Specifically, the upper end of the receiving member 5V is fitted into a through-hole 1Q (see FIG. 11) formed in the inner bottom surface of an adhesive reservoir 1C (see FIG. 10) that is a recessed portion that opens upward and is provided in the top plate 1T of the cover member 1, and is fixed to the cover member 1 by an adhesive applied to the adhesive reservoir 1C. The lower end of the receiving member 5V is fitted into a recess 3QV (see the upper view of FIG. 12) formed in the inner bottom surface of a cylindrical adhesive reservoir 3CV that is open upward and is provided in the bottom plate 3B of the base member 3, and is fixed to the base member 3 by an adhesive applied to the adhesive reservoir 3CV.

[0073] As shown in Figure 11, a pair of V-grooves 2V are formed in the front protrusion 2TF of the lens holding member 2, and the receiving member 5V is clamped between the pair of V-grooves 2V and a piezoelectric driving unit PD that is biased inward (toward the optical axis OA) by a biasing member 6.

[0074] The biasing member 6 is configured to bias the piezoelectric driver PD toward the receiving member 5V. In the example shown in FIG. 11 , the biasing member 6 is configured as a leaf spring member formed by pressing a titanium copper metal plate. The metal plate may be made of stainless steel. The biasing member 6 has both ends fixed to the front protrusion 2TF of the lens holding member 2. Specifically, a clamping portion 2W is formed in the front protrusion 2TF of the lens holding member 2. The clamping portion 2W is a groove configured to clamp the fixed portion 6A of the biasing member 6, and includes a left clamping portion 2WL and a right clamping portion 2WR. In this way, the biasing member 6 is fixed to the lens holding member 2 and configured to press the piezoelectric driver PD toward the receiving member 5V fixed to the fixed-side member FB (the cover member 1 and the base member 3). The biasing member 6 is also configured to press a pair of V-shaped grooves 2V toward the receiving member 5V. The biasing member 6 is configured to be movable in the optical axis direction together with the lens holding member 2.

[0075] Next, with reference to FIGS. 14 to 16, the biasing member 6 constituting the lens driving device 101V will be described in detail. FIG. 14 is a perspective view of the biasing member 6 and corresponds to FIG. 6. Specifically, the upper view of FIG. 14 is a perspective view of the biasing member 6 in a state where the piezoelectric drive unit PD has been removed. The lower view of FIG. 14 is a perspective view of the biasing member 6 in a state where the piezoelectric drive unit PD has been attached. FIG. 15 is a rear view of the biasing member 6 and corresponds to FIG. 7. Specifically, the upper view of FIG. 15 is a rear view of the biasing member 6 in a state where the piezoelectric drive unit PD has been removed. The lower view of FIG. 15 is a rear view of the biasing member 6 in a state where the piezoelectric drive unit PD has been attached. FIG. 16 is a left side view of the biasing member 6 and corresponds to FIG. 8. Specifically, the upper view of FIG. 16 is a left side view of the biasing member 6 in a state where the piezoelectric drive unit PD has been removed. The lower view of FIG. 16 is a left side view of the biasing member 6 in a state where the piezoelectric drive unit PD has been attached.

[0076] The biasing member 6 constituting the lens driving device 101V differs from the linear biasing member 6 (see the upper diagram of FIG. 6) constituting the lens driving device 101 in that the elastic deformation portion 6E is bent into a U-shape, as shown in the upper diagram of FIG. 14. Furthermore, the biasing member 6 constituting the lens driving device 101V differs from the linear fixed portion 6A (see the upper diagram of FIG. 6) constituting the lens driving device 101 in that the fixed portion 6A is bent into an L-shape, as shown in the upper diagram of FIG. 14.

[0077] Furthermore, the elastic deformation portion 6E of the biasing member 6 constituting the lens driving device 101V differs from the elastic deformation portion 6E of the biasing member 6 constituting the lens driving device 101 in that it has a narrow width portion 6C. In other respects, the biasing member 6 constituting the lens driving device 101V and the biasing member 6 constituting the lens driving device 101 are the same.

[0078] The narrow width portions 6C are used to adjust the pressing load of the biasing member 6 when the biasing member 6 presses the piezoelectric driver PD against the receiving member 5V. Typically, the pressing load of the biasing member 6 is adjusted to be smaller as the width of the narrow width portions 6C in the Z-axis direction becomes smaller, and is adjusted to be smaller as the number of narrow width portions 6C increases.

[0079] In the illustrated example, the elastic deformation portion 6E includes a left-side elastic deformation portion 6EL and a right-side elastic deformation portion 6ER. The left-side elastic deformation portion 6EL includes a left-side narrow portion 6CL, and the right-side elastic deformation portion 6ER includes a right-side narrow portion 6CR. The left-side narrow portion 6CL includes a first left-side narrow portion 6CL1 and a second left-side narrow portion 6CL2, and the right-side narrow portion 6CR includes a first right-side narrow portion 6CR1 and a second right-side narrow portion 6CR2.

[0080] Specifically, the first left narrow portion 6CL1 is formed by cutting out a portion of each of the upper and lower edges of the left elastic deformation portion 6EL so that the upper and lower edges are vertically symmetrical. However, the first left narrow portion 6CL1 may be formed by cutting out a portion of each of the upper and lower edges of the left elastic deformation portion 6EL so that the upper and lower edges are vertically asymmetrical, or by cutting out a portion of either the upper or lower edge of the left elastic deformation portion 6EL. The same applies to the second left narrow portion 6CL2, the first right narrow portion 6CR1, and the second right narrow portion 6CR2. In the illustrated example, the narrow portion 6C is realized by notching using a circular punch, and the width of the narrow portion 6C in the Z-axis direction is adjusted by changing the diameter of the circular punch. Specifically, the width of the narrow portion 6C in the Z-axis direction is adjusted so that it decreases as the diameter of the circular punch increases.

[0081] In this way, the pressing load of the biasing member 6 can be easily adjusted by forming the narrow width portion 6C, without changing the plate thickness of the metal plate that constitutes the biasing member 6. Therefore, employing a biasing member 6 having an elastically deforming portion 6E that can form the narrow width portion 6C brings about the effect of being able to flexibly absorb variations in the pressing load caused by manufacturing tolerances of the biasing member 6, etc.

[0082] As described above, the lens driving device 101 (or lens driving device 101V) according to an embodiment of the present disclosure includes the fixed member FB, the lens holding member 2 capable of holding the lens body LS, the piezoelectric driving unit PD provided on one of the fixed member FB and the movable member MB including the lens holding member 2 and the movable member MB, and configured to have a piezoelectric element 8 extending in a direction intersecting the optical axis direction, the receiving member 5 (or receiving member 5V) provided on the other of the movable member MB and the fixed member FB and in contact with the piezoelectric driving unit PD, and the biasing member 6 that biases the piezoelectric driving unit PD toward the receiving member 5 (or receiving member 5V). In the example shown in FIG. 2, the piezoelectric driving unit PD is provided on the fixed member FB (base member 3), and in the example shown in FIG. 11, the piezoelectric driving unit PD is provided on the movable member MB (lens holding member 2).

[0083] In the lens driving device 101 (or lens driving device 101V), the movement of the piezoelectric element 8 moves the lens holding member 2 in the optical axis direction relative to the fixed-side member FB. The biasing member 6 is formed of a leaf spring member and, as shown in the upper diagram of FIG. 6 or the upper diagram of FIG. 14, has a fixed portion 6A fixed to one of the movable-side member MB and the fixed-side member FB, a support portion 6S supporting the piezoelectric driver PD, and an elastically deformable elastic portion 6E provided between the fixed portion 6A and the support portion 6S. The support portion 6S has a plate-shaped base portion 6SC facing the piezoelectric driver PD and a convex portion 6P protruding from one surface of the base portion 6SC toward the piezoelectric driver PD. The base portion 6SC faces, for example, the surface of the piezoelectric driver PD opposite the side on which the receiving member 5 (or receiving member 5V) is disposed. The piezoelectric driver PD is fixed to the convex portion 6P. This configuration has the effect of realizing fixing and biasing of the piezoelectric driver PD with a simple structure.

[0084] 7, the protrusions 6P may be provided at a first position PS1 and a second position PS2 that are spaced apart from each other in the extension direction (Y-axis direction) of the piezoelectric element 8. This configuration brings about the effect of appropriately fixing the piezoelectric driver PD that moves with two nodes ND.

[0085] At least two protrusions 6P may be provided at each of the first position PS1 and the second position PS2, side by side in a direction intersecting the extension direction of the piezoelectric element 8. For example, as shown in the upper diagram of FIG. 7, at the first position PS1, an upper left protrusion 6PUL and a lower left protrusion 6PDL are provided side by side in a direction (Z-axis direction) perpendicular to the extension direction (Y-axis direction) of the piezoelectric element 8, and at the second position PS2, an upper right protrusion 6PUR and a lower right protrusion 6PDR are provided side by side in a direction (Z-axis direction) perpendicular to the extension direction (Y-axis direction) of the piezoelectric element 8. In this configuration, a wider range in the Z-axis direction on the front surface (X1-side surface) of the piezoelectric driver PD is supported by the protrusions 6P compared to a configuration in which one protrusion 6P is provided at each of the first position PS1 and the second position PS2. Therefore, this configuration has the effect of stably fixing the piezoelectric driver PD.

[0086] The base portion 6SC may have an elongated protrusion 6Q protruding from one surface. In this case, the protrusion 6Q may be formed to be located at least between the first position PS1 and the second position PS2 and extend in the extension direction (Y-axis direction) of the piezoelectric element 8. In the illustrated example, the base portion 6SC has one elongated rounded rectangular protrusion 6Q, but two elongated protrusions may be formed. In this case, each of the two elongated protrusions is formed to be partially parallel to each other in the Y-axis direction. The same applies to the case where three or more elongated protrusions are formed on the base portion 6SC. This configuration has the effect of increasing the rigidity of the base portion 6SC. In other words, this configuration has the effect of suppressing bending of the base portion 6SC due to bending vibration of the piezoelectric driver PD, and therefore suppressing variations in the pressing load applied by the biasing member 6.

[0087] As shown in the upper diagram of FIG. 8, the protrusion 6Q may be formed to protrude rearward (in the X2 direction), which is the same direction as the protrusion 6P, from the rear surface (the surface on the X2 side) of the base 6SC, and the protrusion amount (protrusion height PT2) may be smaller than the protrusion amount (protrusion height PT1) of the protrusion 6P. Alternatively, as shown in the upper diagram of FIG. 7, the protrusion 6Q may be formed to extend continuously at least from the first position PS1 to the second position PS2. That is, the first position PS1 and the second position PS2 may be included within the formation area of ​​the protrusion 6Q. In the example shown in the upper diagram of FIG. 7, the protrusion 6Q is formed so that the width WD2, which is the distance between the left end and the right end, is greater than the width WD1, which is the distance between the left bent portion 6NL and the right bent portion 6NR. This configuration has the effect of increasing the rigidity of the base 6SC while enabling the base 6SC to be thinned. That is, this configuration has the effect of realizing a thin and less flexible base 6SC.

[0088] As shown in the lower diagram of FIG. 8, the piezoelectric driver PD may have a first edge (upper edge UG) and a second edge (lower edge DG) that face each other in a direction (Z-axis direction) perpendicular to its extension direction (Y-axis direction). Furthermore, the protrusion 6P provided at each of the first position PS1 and the second position PS2 may have a first portion that contacts the first edge (upper edge UG) and a second portion that contacts the second edge (lower edge DG). Specifically, as shown in the upper diagram of FIG. 7, at the first position PS1, the protrusion 6P may have an upper-left protrusion 6PUL as the first portion that contacts the first edge (upper edge UG) and a lower-left protrusion 6PDL as the second portion that contacts the second edge (lower edge DG). Furthermore, at the second position PS2, the convex portion 6P may have an upper right convex portion 6PUR as a first portion that contacts the first edge portion (upper edge portion UG) and a lower right convex portion 6PDR as a second portion that contacts the second edge portion (lower edge portion DG). As shown in the lower diagram of Fig. 7, the first portions (upper left convex portion 6PUL and upper right convex portion 6PUR) may be provided so that a portion (upper half) of each of the first portions extends outside (toward the Z1 side) of the first edge portion (upper edge portion UG), and the second portions (lower left convex portion 6PDL and lower right convex portion 6PDR) may be provided so that a portion (lower half) of each of the second portions extends outside (toward the Z2 side) of the second edge portion (lower edge portion DG). In this configuration, the first edge (upper edge UG) and second edge (lower edge DG), which are positioned apart from each other in the vertical direction (Z-axis direction), which is perpendicular to the extension direction (Y-axis direction) of the moving piezoelectric drive unit PD, are supported by the tip surface ES (see the upper diagram in Figure 8) of the convex portion 6P. Therefore, this configuration has the effect of stably supporting the piezoelectric drive unit PD.

[0089] The protrusion 6P is preferably configured so that the tip surface ES is flat, and the third adhesive AD3 is attached to the outer peripheral surface CS, as shown in the upper diagram of FIG. 8. In the illustrated example, the third adhesive AD3 is applied so as to adhere to the entire tip surface ES and the entire periphery of the outer peripheral surface CS, as shown in the upper diagram of FIG. 7. However, the third adhesive AD3 may be applied so as to adhere to only a portion of the tip surface ES or only a portion of the outer peripheral surface CS. This configuration prevents a wide area of ​​the front surface of the flexible wiring board 10 from being adhesively fixed to the base portion 6SC of the support portion 6S, thereby preventing interference with the bending vibration of the piezoelectric driver PD.

[0090] The first position PS1 and the second position PS2 preferably correspond to the position of a node ND (see FIG. 3) of the piezoelectric element 8 that performs bending vibration. This configuration prevents portions of the flexible wiring board 10 other than the position AP (see FIG. 3) that corresponds to the node ND from being adhesively fixed to the base portion 6SC of the support portion 6S, thereby providing the effect of preventing interference with the bending vibration of the piezoelectric drive portion PD.

[0091] 14, the elastic deformation portion 6E may have a narrow width portion 6C for adjusting the load (pressing load) caused by the urging member 6. This configuration brings about the effect of making it easier to adjust the load (pressing load) caused by the urging member 6 compared to changing the plate thickness of the metal plate constituting the urging member 6 or the length in the extension direction of the elastic deformation portion 6E.

[0092] As shown in the upper diagram of FIG. 6, the elastic deformation portion 6E may have a wide portion 6W for suppressing twisting of the biasing member 6. The wide portion 6W may be disposed on both sides of the support portion 6S and include at least two connecting portions. In the illustrated example, as shown in the upper diagram of FIG. 6, the wide portion 6W includes a left wide portion 6WL disposed on the left side of the support portion 6S and a right wide portion 6WR disposed on the right side of the support portion 6S. The left wide portion 6WL includes three connecting portions (upper left connecting portion 6WUL, left central connecting portion 6WML, and lower left connecting portion 6WDL), and the right wide portion 6WR includes three connecting portions (upper right connecting portion 6WUR, right central connecting portion 6WMR, and lower right connecting portion 6WDR). This configuration has the effect of suppressing twisting of the biasing member 6 due to bending vibration of the piezoelectric driver PD. In addition, this configuration prevents the rear surface (X2 side surface) of the base 6SC from tilting relative to the YZ plane, which in turn has the effect of preventing the bonding portion 10B from peeling off from the tip surface ES of the convex portion 6P due to bending vibration of the piezoelectric element 8.

[0093] The piezoelectric driver PD may be provided on the fixed member FB. In the example shown in Fig. 2, the piezoelectric driver PD is fitted and fixed, via a biasing member 6, into a pair of clamping portions 3W formed on each of the left front column portion 3PFL and the right front column portion 3PFR of the base member 3. This configuration has the effect of realizing a lighter weight for the movable member MB compared to when the piezoelectric driver PD is provided on the movable member MB.

[0094] Furthermore, in the lens driving device 101 according to the embodiment of the present disclosure, as shown in FIG. 3 , the piezoelectric driving unit PD includes a contact member 9 fixed to one surface (X2-side surface) of the piezoelectric element 8 facing the receiving member 5, and a flexible wiring board 10 fixed to the other surface (X1-side surface) of the piezoelectric element 8, on which a plurality of conductive portions (conductive patterns) are formed and which are electrically connected to the electrodes ED of the piezoelectric element 8. The piezoelectric element 8 and the contact member 9 are fixed with one adhesive (first adhesive AD1), and the flexible wiring board 10 and the support portion 6S of the biasing member 6 are fixed with another adhesive (third adhesive AD3). The Young's modulus of the other adhesive (third adhesive AD3) is smaller than that of the first adhesive (first adhesive AD1), as shown in the table of FIG. 9 . This configuration has the effect of realizing holding and biasing of the piezoelectric driving unit PD with a simple structure. In addition, this configuration has the advantage that the movement of the piezoelectric element 8 can be appropriately transmitted to the contact member 9 compared to when the one adhesive (first adhesive AD1) placed on one side of the piezoelectric element 8 is harder than the other adhesive (third adhesive AD3) placed on the other side of the piezoelectric element 8.

[0095] The piezoelectric element 8 and the flexible wiring board 10 may be fixed via an anisotropic conductive film as the second adhesive AD2. This configuration has the effect of facilitating connection between the piezoelectric element 8 and the flexible wiring board 10.

[0096] The Young's modulus of the anisotropic conductive film serving as the second adhesive AD2 may be smaller than that of the first adhesive AD1. In the first embodiment shown in FIG. 9, the Young's modulus of the anisotropic conductive film serving as the second adhesive AD2 is 0.1 [GPa], and the Young's modulus of the first adhesive AD1 is 4.5 [GPa]. In the second embodiment shown in FIG. 9, the Young's modulus of the anisotropic conductive film serving as the second adhesive AD2 is 0.1 [GPa], and the Young's modulus of the first adhesive AD1 is 4.4 [GPa]. In these configurations, the first adhesive AD1 disposed between the piezoelectric element 8 and the contact member 9 on the vibration transmission direction side of the piezoelectric element 8 (the rear side, or X2 side) is harder than the second adhesive AD2 disposed between the piezoelectric element 8 and the flexible wiring substrate 10 on the opposite side of the piezoelectric element 8 (the front side, or X1 side). Therefore, this configuration has the effect of more appropriately transmitting the motion of the piezoelectric element 8 to the contact member 9 compared to when the first adhesive AD1 is softer than the second adhesive AD2.

[0097] The glass transition temperature (glass transition point) of the third adhesive AD3 is preferably −10°C (the lower limit of the predetermined operating temperature range) or lower, more preferably −20°C or lower. In the second embodiment shown in FIG. 9 , the glass transition temperature of the third adhesive AD3 is approximately −65°C. In this case, the predetermined operating temperature range, which is the temperature range of the environment in which a device such as a smartphone incorporating the camera module CM is expected to be normally used, is higher than the glass transition temperature of the third adhesive AD3. Therefore, the third adhesive AD3 is softer than when the environmental temperature is below the glass transition temperature. Therefore, as long as the device is used within the predetermined operating temperature range, the characteristics of the piezoelectric actuator PD, such as the thrust generated by the piezoelectric actuator PD, do not suddenly change. This is because the temperature of the third adhesive AD3 does not fall below the glass transition temperature and harden. This configuration therefore has the effect of efficiently transmitting vibrations, such as circular motion, of the piezoelectric element 8 to the contact member 9.

[0098] Preferably, the glass transition temperature of the anisotropic conductive film serving as the second adhesive AD2 is higher than the glass transition temperature of the third adhesive AD3. Also, preferably, the glass transition temperature of the first adhesive AD1 is 60°C (the upper limit of the operating temperature range) or higher, higher than the glass transition temperature of the anisotropic conductive film serving as the second adhesive AD2. In the second embodiment shown in FIG. 9, the glass transition temperature of the first adhesive AD1 is 150°C, the glass transition temperature of the second adhesive AD2 is 62°C, and the glass transition temperature of the third adhesive AD3 is -65°C. That is, the glass transition temperature of the second adhesive AD2 (62°C) is higher than the glass transition temperature of the third adhesive AD3 (-65°C). Also, the glass transition temperature of the first adhesive AD1 (150°C) is higher than the upper limit of the operating temperature range (60°C) and higher than the glass transition temperature of the anisotropic conductive film serving as the second adhesive AD2 (62°C). This configuration can prevent the temperature of the first adhesive AD1 from exceeding the glass transition temperature and softening the first adhesive AD1, as long as the device is used within a predetermined operating temperature range. Therefore, this configuration has the effect of efficiently transmitting vibrations such as circular motion of the piezoelectric element 8 to the contact member 9.

[0099] The glass transition temperature of the anisotropic conductive film used as the second adhesive AD2 is preferably equal to or higher than the upper limit (60°C) of the operating temperature range. In the example shown in FIG. 9, the glass transition temperature of the anisotropic conductive film used as the second adhesive AD2 is 62°C, which is higher than the upper limit (60°C) of the operating temperature range. This configuration can prevent the temperature of the second adhesive AD2 from exceeding the glass transition temperature and softening the second adhesive AD2, as long as the device is used within a predetermined operating temperature range. Therefore, this configuration has the effect of efficiently transmitting vibrations, such as circular motion, of the piezoelectric element 8 to the contact member 9.

[0100] As shown in FIG. 8, the support portion 6S of the biasing member 6 may have a plate-shaped base portion 6SC facing the piezoelectric driver PD at a distance from the base portion 6SC and a portion (protrusion 6P) protruding from the base portion 6SC toward the piezoelectric driver PD. The flexible wiring board 10 and the protruding portion (protrusion 6P) may be fixed with a third adhesive AD3 (see the upper diagram in FIG. 7). This configuration forms a gap between the base portion 6SC and the flexible wiring board 10 corresponding to the protrusion height PT1 of the protruding portion (protrusion 6P), thereby preventing the movement of the piezoelectric element 8 from being hindered by the support portion 6S (base portion 6SC). In the illustrated example, the portion protruding from the base portion 6SC toward the piezoelectric driver PD is the protrusion 6P having a circular end face formed by drawing, doweling, or half-blanking. However, it may also be a portion formed by bending (an L-shaped folded piece), such as the bent portion 6N. In this case, the biasing member 6 may be configured, for example, so that each rectangular end surface of the pair of folded pieces contacts a position AP (see Figure 3) corresponding to a node ND at the joint 10B of the flexible wiring board 10, and is adhesively fixed to the joint 10B by a third adhesive AD3.

[0101] The preferred embodiments of the present disclosure have been described above in detail. However, the present invention is not limited to the above-described embodiments. Various modifications or substitutions may be applied to the above-described embodiments without departing from the scope of the present invention. Furthermore, the features described with reference to the above-described embodiments may be combined as appropriate unless technically inconsistent.

[0102] For example, in the lens driving device 101 (or lens driving device 101V) in the above-described embodiment, the lens holding member 2 moves in the optical axis direction relative to the fixed-side member FB due to the movement of the piezoelectric element 8. However, the movement direction of the lens holding member 2 relative to the fixed-side member FB is not limited to the optical axis direction, and may be a direction intersecting the optical axis direction.

[0103] This application claims priority based on Japanese Patent Application No. 2022-117511, filed on July 22, 2022, the entire contents of which are incorporated herein by reference. [Explanation of symbols]

[0104] 1...Cover member 1C...Adhesive reservoir 1H...Through hole 1K...Opening 1M...Protrusion part 1Q...Through hole 1T...Top plate part 2...Lens holding member 2C...Cylindrical part 2G...Guiding part 2H...Through hole 2SD...Lower stopper part 2SU...Upper stopper part 2T... Protruding part 2TF... Front protruding part 2TL... Left protruding part 2TR... Right protruding part 2U... U-shaped groove 2V... V-shaped groove 3... Base member 3A... Outer peripheral wall part 3A1... First side plate part 3A2... Second side plate part 3A3... Third side plate part 3A4...Fourth side plate part 3B...Bottom plate part 3C, 3CV...Adhesive reservoir 3G...Groove 3GL...Left side groove 3GR...Right side groove 3K...Opening 3M...Protrusion 3N...Restriction part 3NL...Left side regulation part 3NR...Right side regulation part 3P...Columnar part 3PBL...Left rear columnar part 3PBR...Right rear columnar part 3PFL...Left front columnar part 3PFR...Right front columnar part 3Q, 3QV...Concave part 3S...Accommodating part 3T...Connecting pin 3W...Clip part 3WL...Left side clamping part 3WR...Right side clamping part 4...Guide shaft 5, 5V...Receiving member 6...Biasing member 6A...Fixing part 6AL...Left side fixed part 6AR Right side fixed part 6C Narrow part 6CL Left side narrow part 6CL1 First left side narrow part 6CL2 Second left side narrow part 6CR Right side narrow part 6CR1 First right side narrow part 6CR2 Second right side narrow part 6E Elastic deformation part 6EL Left side elastic deformation part 6ER Right side elastic deformation part 6H Through hole 6HDL Lower left through hole 6HDR Lower right through hole 6HL Left side through hole 6HR Right side through hole 6HUL Upper left through hole 6HUR Upper right through hole 6N Bending part 6NDL Lower left bending part 6NDR Lower right bending part 6NL Left side bending part 6NR···Right side bent part 6NUL···Upper left bent part 6NUR···Upper right bent part 6P···Protruding part 6PL···Left side bent part 6PDL···Lower left side bent part 6PDR···Lower right side bent part 6PR···Right side bent part 6PUL···Upper left side bent part 6PUR···Upper right side bent part 6Q···Protruding part 6S···Support part 6SC···Base part6SL···Left side support part 6SR···Right side support part 6W···Wide part 6WDL···Lower left connecting part 6WDR···Lower right connecting part 6WL···Left side wide part 6WML···Left center connecting part 6WMR···Right center connecting part 6WR···Right side wide part 6WUL···Upper left connecting part 6WUR···Upper right connecting part 8···Piezoelectric element 9···Contact member 9S, 9Sa···Surface 10···Flexible wiring board 10B···Joint part 10E···Extension part 101, 101V···Lens drive unit AD1···First adhesive AD2···Second adhesive AD3···Third adhesive AP···Position CM···Camera module CP···Contact point CS···Outer surface DE···Bottom end piece DG···Lower edge ED··Electrode ES···Tip surface FB··Fixed side member GM···Guide mechanism GML···Left side guide mechanism GMR···Right side guide mechanism HS···Housing IS···Image sensor LE···Left end LS··Lens body MB···Movable side member ND···Node ND1···Section 1 ND2···Section 2 OA···Optical axis PD···Piezoelectric actuator PS1···First position PS2···Second position RE···Right end UE···Upper end piece UG···Upper edge

Claims

1. A fixed side member; a lens holding member capable of holding a lens body; a piezoelectric driving unit provided on one of the movable-side member including the lens holding member and the fixed-side member, the piezoelectric driving unit including a piezoelectric element extending in a direction intersecting with the optical axis direction; a receiving member provided on the other of the movable member and the fixed member, the receiving member being in contact with the piezoelectric driving unit; a biasing member that biases the piezoelectric driving portion toward the receiving member, a lens driving device in which the lens holding member moves relative to the fixed member by movement of the piezoelectric element, the biasing member is configured by a leaf spring member, and has a fixed portion fixed to one of the movable-side member and the fixed-side member, a support portion supporting the piezoelectric drive unit, and an elastically deformable portion provided between the fixed portion and the support portion, the piezoelectric driving unit has a contact member fixed to one surface of the piezoelectric element on the receiving member side, and a flexible wiring board fixed to the other surface of the piezoelectric element, the piezoelectric element and the contact member are fixed by an adhesive; the flexible wiring board and the support portion are fixed by another adhesive; The Young's modulus of the second adhesive is smaller than the Young's modulus of the first adhesive. A lens driving device characterized by:

2. the piezoelectric element and the flexible wiring board are fixed via an anisotropic conductive film; The lens driving device according to claim 1 .

3. the Young's modulus of the anisotropic conductive film is smaller than the Young's modulus of the first adhesive; 3. The lens driving device according to claim 2.

4. The glass transition temperature of the other adhesive is −10° C. or lower. The lens driving device according to any one of claims 1 to 3.

5. the glass transition temperature of the anisotropic conductive film is higher than the glass transition temperature of the other adhesive; the glass transition temperature of the first adhesive is 60° C. or higher, which is higher than the glass transition temperature of the anisotropic conductive film; 4. The lens driving device according to claim 2 or 3.

6. The glass transition temperature of the anisotropic conductive film is 60°C or higher.

6. The lens driving device according to claim 5.

7. The glass transition temperature of the other adhesive is −10° C. or lower.

6. The lens driving device according to claim 5.

8. the support portion has a plate-shaped base portion facing the piezoelectric drive portion while being spaced apart from the piezoelectric drive portion, and a portion protruding from the base toward the piezoelectric drive portion, and the flexible wiring board and the portion are fixed together by the separate adhesive.

5. The lens driving device according to claim 4.

9. a lens driving device according to claim 1, claim 2, or claim 3; the lens body held by the lens holding member; an imaging element disposed opposite the lens body, Camera module.

Images