JP6024798B1 - Lens drive device - Google Patents

Abstract

A lens driving device capable of suppressing vibration of a lens holder is provided. A lens holder includes a barrel portion having a cylindrical shape, and first and second abutting portions having a plane located on an outer peripheral surface of the barrel portion and abutting against a shaft. 37. One end portion 71 of the spring member 70 is located between the second corner portion 11 b to the third triangular portion 11 c when viewed from the optical axis direction OA of the lens held by the lens holder 30, and the other end of the spring member 70. The part 72 is in contact with the shaft 40 so that the urging force is directed toward the optical axis Z of the lens held by the lens holder 30. [Selection] Figure 2

Description

The present invention relates to a lens driving device that drives a lens.

  A base, a shaft disposed on the base, a lens holder disposed on the base so as to contact the shaft, a piezoelectric actuator that applies a driving force to the shaft to move the lens holder, and the shaft and the lens holder There is known a lens driving device that includes a spring member that applies a biasing force to a shaft so as to abut the shaft (see, for example, Patent Document 1).

JP 2013-250297 A Japanese Patent Laying-Open No. 2015-089183

  However, the lens driving device described in Patent Document 1 may have the following problems.

  In the lens driving device described in Patent Document 1, one end of the spring member is formed in an L shape, and the spring member and the shaft are in contact with each other at two locations. The shaft and the lens holder are in contact at one place. Since the urging force of the spring member acts at two locations in contact with the shaft, the shaft receives the urging force from the spring member at two locations in contact with the spring member. The resultant force of each urging force acts on the shaft, and the direction of the resultant force is the direction in which the spring portion presses the shaft.

  It is difficult to properly abut the end portion formed in an L shape and the shaft, and each urging force does not necessarily act appropriately at the two locations. For example, of the L-shaped portion at one end, the portion extending in the direction along the movable direction of the spring member has a sufficient urging force compared to the portion extending in the direction intersecting the movable direction of the spring member. Since it is difficult to obtain, each urging force may not act properly at the two locations. If each urging force does not act properly, a desired resultant force cannot be obtained, and the direction of the resultant force is different from the desired direction. In this case, the biasing force of the spring member does not act properly, and it becomes difficult to suppress the vibration of the lens holder.

  An object of this invention is to provide the lens drive device which can suppress the vibration of a lens holder.

  A lens driving device according to the present invention has a rectangular shape in a plan view, and includes a base having first and second corners diagonally positioned with each other and third and fourth corners diagonally positioned with respect to each other. A shaft disposed at the first corner, a lens holder disposed on the base so as to be in contact with the shaft and holding the lens, and a lens light disposed at the first corner and retained by the lens holder A piezoelectric actuator that applies a driving force to the shaft so as to move the lens holder in the axial direction, and an end portion that is disposed along the lens holder on the side of the lens holder and fixed to the lens holder, and the shaft And a spring member that applies a biasing force to the shaft from the other end so that the shaft and the lens holder come into contact with each other, and the lens holder has a cylindrical body When A first contact portion and a second contact portion located on the outer peripheral surface of the body portion and having a flat surface that contacts the shaft, and one end portion of the spring member is from the optical axis direction of the lens held by the lens holder. When viewed, the second end portion of the spring member is positioned between the second corner portion and the triangular portion, and the other end portion of the spring member is in contact with the shaft so that the urging force is directed to the optical axis of the lens held by the lens holder. .

  In the lens driving device according to the present invention, the lens holder is in contact with the shaft at two locations of the first and second contact portions. For this reason, the other end part of a spring member should just contact | abut to a shaft in one place. Therefore, the other end portion of the spring member is appropriately brought into contact with the shaft, and the biasing force acting from the other end portion is applied to the shaft at a desired value and in a desired direction. Since the urging force acting from the other end is applied to the shaft in a desired direction and in a desired direction, the shaft and the first and second abutting portions abut on each other appropriately. Therefore, the urging force acting from the other end of the spring member is appropriately transmitted to the lens holder as a resultant force from the first and second contact portions via the shaft and the first and second contact portions. One end portion of the spring member is located between the second corner portion and the third triangle portion when viewed from the optical axis direction of the lens held by the lens holder. For this reason, the reaction force acting on the lens holder is applied to the lens holder from a position facing the urging force acting from the other end. That is, a force toward the optical axis of the lens is applied to the lens holder from both one end and the other end of the spring member. As a result, the vibration of the lens holder can be effectively suppressed.

  When the first virtual plane including the plane of the first contact portion and the second virtual plane including the plane of the second contact portion are viewed from the optical axis direction of the lens held by the lens holder, the body portion You may cross | intersect inside the trunk | drum rather than the outer peripheral surface of. In this case, since the outer peripheral surface of the trunk portion can be brought closer to the shaft, the trunk portion can be designed to increase the outer diameter and inner diameter of the trunk portion. If the inner diameter of the barrel can be enlarged, a lens having a larger aperture can be held by the lens holder.

  A magnet disposed on the lens holder; and a magnetism detecting element disposed on the lens holder so as to face the magnet. The magnet is positioned on the opposite side of the lens holder from the spring member. You may do it. In this case, since the spring member is located on the third triangle side and the magnet is located on the fourth square side with respect to the imaginary line so as to connect one end and the other end of the spring member, the lens holder, the spring In the mass system including the member and the magnet, mass unbalance with respect to the imaginary line is reduced. Thereby, the vibration of the lens holder can be more reliably suppressed.

  There may be further provided a restricting member that is disposed on the opposite side of the lens holder from the spring member and restricts the movement of the spring member in the direction away from the lens holder. In this case, the spring member is prevented from being detached from the lens holder and the shaft, and the biasing force of the spring member is appropriately applied to the shaft. Thereby, the vibration of the lens holder can be more reliably suppressed.

  ADVANTAGE OF THE INVENTION According to this invention, the lens drive device which can suppress the vibration of a lens holder can be provided.

It is a perspective view which shows the lens drive device which concerns on one Embodiment of this invention. It is a disassembled perspective view which shows the lens drive device which concerns on this embodiment. It is a disassembled perspective view which shows a base and its periphery. It is a disassembled perspective view which shows a lens holder and its periphery. It is a schematic diagram which shows a shaft and its periphery. It is a perspective view which shows a spring member. It is a schematic diagram for demonstrating the urging | biasing force which acts from a spring member. It is a schematic diagram for demonstrating the drive state of the lens drive device which concerns on this embodiment. It is a schematic diagram for demonstrating the drive state of the lens drive device which concerns on a comparative example.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Note that in the description of the drawings, the same reference numerals are used for the same elements or elements having the same functions, and redundant description is omitted.

  First, the configuration of the lens driving device 1 will be described with reference to FIGS. FIG. 1 is a perspective view showing a lens driving device according to this embodiment. FIG. 2 is an exploded perspective view showing the lens driving device according to the present embodiment. FIG. 3 is an exploded perspective view showing the base and its periphery. FIG. 4 is an exploded perspective view showing the lens holder and its periphery. FIG. 5 is a schematic view showing the shaft and its periphery. FIG. 6 is a perspective view showing the spring member.

  The lens driving device 1 includes a base 10, a cover 20, a lens holder 30, a piezoelectric actuator unit, a spring member 70, a regulating member 80, and a position detection unit, as shown in FIGS. The lens driving device 1 is a device that drives a camera lens mounted on, for example, a portable information terminal. In the present embodiment, the planar shape of the lens driving device 1 is set to, for example, 8.5 mm × 8.5 mm. In the present embodiment, the base 10 and the cover 20 function as a housing.

  As shown in FIG. 3, the base 10 has a bottom 11, a first side wall 12a, a second side wall 12b, a third side wall 12c, and a fourth side wall 12d. The base 10 is formed of, for example, a liquid crystal polymer containing a filler (such as glass fiber or inorganic material). The base 10 (bottom part 11) has a rectangular shape in plan view. In the present embodiment, the rectangular shape includes not only a shape whose corner is a right angle but also a shape whose corner is chamfered or rounded.

  The bottom portion 11 includes a first corner portion 11a, a second corner portion 11b, a third triangular portion 11c, and a fourth corner portion 11d. The first and second corner portions 11a and 11b are located diagonally to each other, and the third and fourth corner portions 11c and 11d are located diagonally to each other. A perfect circular opening 11 e is formed in the bottom 11.

  The first side wall portion 12a is erected from the first corner portion 11a. The second side wall portion 12b is erected from the second corner portion 11b. The third side wall portion 12c is erected from the third triangular portion 11c. The fourth side wall portion 12d is erected from the fourth corner portion 11d. The first, second, third, and fourth side wall portions 12 a, 12 b, 12 c, and 12 d are formed integrally with the bottom portion 11. The first, second, third, and fourth side wall portions 12a, 12b, 12c, and 12d have inner peripheral surfaces that are curved along the shape of the opening 11e. The bottom portion 11 and the first, second, third, and fourth side wall portions 12a, 12b, 12c, and 12d define a space that accommodates a lens holder 30 described later.

  A semi-cylindrical notch 13a is formed inside the first side wall 12a. In the first corner portion 11a, a circular hole portion 11f having a central axis substantially the same as the notch portion 13a is formed. A weight 52 of a piezoelectric actuator 50 described later is inserted into the hole 11f. A lead wire notch 13b is formed in the first side wall 12a. Respective lead wires 53a and 53b described later are inserted into the lead wire cutout portion 13b.

  On the inner side of the second, third, and fourth side wall portions 12b, 12c, and 12d, positions corresponding to a first protrusion 33, a second protrusion 34, and a third protrusion 35 (see FIG. 4) described later. In addition, the notches 13c, 13d, and 13e are formed. Each notch part 13c, 13d, 13e is formed away from each other so as not to contact the corresponding projecting part 33, 34, 35.

  As shown in FIG. 2, the cover 20 has a hollow, substantially rectangular parallelepiped shape that is open on one side. The cover 20 includes a surface portion 21 that faces the bottom portion 11 of the base 10 and side surface portions 22 that respectively extend from the four sides of the surface portion 21. In the surface portion 21, a perfectly circular opening 21 a is formed at a position facing the opening 11 e of the bottom portion 11. The cover 20 is made of, for example, SPCC (cold rolled steel).

  As shown in FIG. 4, the lens holder 30 includes a body portion 31, a first contact portion 36, and a second contact portion 37. The lens holder 30 is disposed in an accommodation space (on the base 10) defined by the bottom portion 11 and the first, second, third, and fourth side wall portions 12a, 12b, 12c, and 12d.

  The trunk | drum 31 is exhibiting the cylinder shape and becomes cross-sectional perfect circle shape. The body portion 31 is formed of, for example, LCP (liquid crystal polymer). An internal thread portion 31 b is formed inside the body portion 31. The body portion 31 includes a first projecting portion 33, a second projecting portion 34, and a third projecting portion 35. Each protrusion part 33,34,35 protrudes toward the outer side from the outer peripheral surface 31a. Each protrusion 33, 34, 35 is formed integrally with the body 31.

  The female screw portion 31b corresponds to the male screw portion of the lens barrel LB that holds the lens. The lens barrel LB is attached to the lens holder 30 via the female screw portion 31b. As a result, the lens is indirectly held by the lens holder via the lens barrel LB. The lens may be held by the lens holder without using the lens barrel LB. The lens is exposed to the outside through the opening 11 e of the bottom 11 and the opening 21 a of the cover 20.

  The 1st protrusion part 33 is arrange | positioned in the position corresponding to the 2nd corner | angular part 11b. The 1st protrusion part 33 has the protrusion part 33a and the spring fixing | fixed part 33b. The protrusion 33a has a substantially rectangular parallelepiped shape. The protruding portion 33a is formed with a hemispherical spherical portion 33c protruding from the side surface when viewed from the optical axis direction of the lens. The spring fixing portion 33b is formed at the base of the protruding portion 33a. The spring fixing portion 33b has a protruding shape so that one end portion 71 of a spring member 70 described later is engaged.

  The 2nd protrusion part 34 is arrange | positioned in the position corresponding to the 1st triangular part 11c. The 2nd protrusion part 34 has two protrusion part 34a, 34b. Each protruding portion 34a, 34b has a substantially triangular shape in plan view. The protruding portions 34a and 34b are spaced apart from each other along the optical axis direction OA of the lens. The interval between the protruding portions 34a and 34b is wider than the width of a base 73 of a spring member 70 described later. Holes 34c and 34d are formed in the protruding portions 34a and 34b, respectively. The holes 34c and 34d are formed so that their central axes are substantially the same. A regulating member 80 described later is inserted into each of the holes 34c and 34d.

  The 3rd protrusion part 35 is arrange | positioned in the position corresponding to the 4th square part 11d. A magnet 91 described later is fixed to the third protrusion 35.

  The first contact portion 36 includes a protruding portion 36a and a slider 36b. The protruding portion 36a has a substantially triangular prism shape. The protruding portion 36 a is disposed on the outer peripheral surface 31 a of the body portion 31. The protrusion 36a is formed integrally with the outer peripheral surface 31a. The protrusion 36a is located at the first corner 11a. The protrusion 36a has a first surface and a second surface extending along the optical axis direction OA of the lens. The direction in which the ridgeline formed by the first surface and the second surface extends is parallel to the optical axis direction OA of the lens.

  The slider 36b is fixed to the protruding portion 36a. The slider 36b has a first portion that faces the first surface of the protruding portion 36a and a second portion that extends in a direction intersecting the first portion (in the present embodiment, a direction orthogonal to the first portion). The first portion of the slider 36b is in contact with the first surface of the protruding portion 36a, and the second portion of the slider 36b is in contact with one end surface of the protruding portion 36a. The first portion of the slider 36b has a flat surface 36c on the side opposite to the surface that contacts the first surface of the protruding portion 36a. That is, the first contact portion 36 has a flat surface 36c. The slider 36b is formed of, for example, a stainless steel plate.

  The second contact portion 37 includes a projecting portion 37a and a slider 37b. The protruding portion 37a has a substantially triangular prism shape. The protruding portion 37 a is disposed on the outer peripheral surface 31 a of the body portion 31. The protrusion 37a is formed integrally with the outer peripheral surface 31a. The protrusion 37a is located at the first corner 11a so as to be adjacent to the protrusion 36a when viewed from the optical axis direction OA of the lens. The protruding portion 37a has a first surface and a second surface extending along the optical axis direction OA of the lens. The direction in which the ridgeline formed by the first surface and the second surface extends is parallel to the optical axis direction OA of the lens. The first surface of the projecting portion 36 a and the first surface of the projecting portion 37 a face each other in the circumferential direction of the body portion 31.

  The slider 37b is fixed to the protruding portion 37a. The slider 37b has a first portion that faces the first surface of the protruding portion 37a, and a second portion that extends in a direction intersecting the first portion (in the present embodiment, a direction orthogonal to the first portion). The first portion of the slider 37b is in contact with the first surface of the protruding portion 37a, and the second portion of the slider 37b is in contact with one end surface of the protruding portion 36a. The first portion of the slider 37b has a flat surface 37c on the side opposite to the surface that contacts the first surface of the protruding portion 37a. That is, the second contact portion 37 has a flat surface 37c. The slider 37b is formed of, for example, a stainless steel plate.

  The flat surface 36c and the flat surface 37c face each other in the circumferential direction of the body portion 31 in a state where the sliders 36b and 37b are fixed to the projecting portions 36a and 37a. As shown in FIG. 5, the first virtual plane 38a including the plane 36c of the first contact portion 36 and the second virtual plane 38b including the plane 37c of the second contact portion 37 are at a predetermined angle θ. Crossed. When viewed from the optical axis direction OA of the lens, the intersection point P between the first virtual plane 38a and the second virtual plane 38b is located on the inner side of the body portion 31 with respect to the outer peripheral surface 31a. In the present embodiment, the first virtual plane 38a and the second virtual plane 38b are orthogonal (θ = 90 °).

  As shown in FIG. 3, the piezoelectric actuator unit includes a piezoelectric actuator 50, a shaft 40, and a flexible substrate 60 that is electrically connected to the piezoelectric actuator 50.

  The piezoelectric actuator 50 electrically connects the piezoelectric element 51, which is an electromechanical conversion element that expands and contracts in the optical axis direction OA of the lens, the weight 52 connected to one end of the piezoelectric element 51, and the flexible substrate 60. Two lead wires 53a and 53b.

  The piezoelectric element 51 is a so-called multilayer piezoelectric actuator, and includes an element body in which a plurality of piezoelectric layers and internal electrodes are alternately stacked, and a pair of external electrodes 51a and 51b. One of the plurality of internal electrodes facing each other with the piezoelectric layer interposed therebetween is exposed on one side surface of the piezoelectric element 51 and connected to the external electrode 51a disposed on the side surface. Of the plurality of internal electrodes, the other internal electrode facing the piezoelectric layer is exposed on the side surface facing the one side surface and connected to the external electrode 51b disposed on the side surface. The pair of external electrodes 51a and 51b are connected to the flexible substrate 60 via corresponding lead wires 53a and 53b.

  The weight 52 is connected to one end of the piezoelectric element 51 so that the displacement due to the expansion and contraction of the piezoelectric element 51 is generated only on the shaft 40 side. In the present embodiment, the weight 52 has a cylindrical shape. The weight 52 is made of, for example, a tungsten alloy. The weight 52 is inserted into the hole portion 11f of the first corner portion 11a. Each lead wire 53a, 53b extends from the inner side of the base 10 to the outer side through a notch 13b formed in the first corner portion 11a.

  The shaft 40 is connected to the other end of the piezoelectric element 51 and can move in the optical axis direction OA by expansion and contraction of the piezoelectric element 51. The shaft 40 has a cylindrical shape, and is formed of, for example, CFRP (carbon-fiber-reinforced plastic). The shaft 40 is disposed at the first corner portion 11 a via the piezoelectric actuator 50. As shown in FIG. 5, the shaft 40 abuts against the flat surfaces 36 c and 37 c by the outer peripheral surface 41 of the shaft. The outer peripheral surface 41 generates friction between the flat surfaces 36c and 37c. A gap t is provided between the outer peripheral surface 41 and the outer peripheral surface 31a. Thereby, the outer peripheral surface 41 is contact | abutted only to each plane 36c, 37c.

  The flexible substrate 60 is a so-called flexible printed circuit (FPC). As shown in FIG. 3, the flexible substrate 60 is attached to the outside of the second side wall portion 12b and the fourth side wall portion 12d.

  With the above configuration, the piezoelectric actuator 50 applies a driving force to the shaft 40 so as to move the lens holder 30 in the optical axis direction OA of the lens. The shaft 40 transmits a driving force to the lens holder 30 by a frictional force. The piezoelectric actuator 50 can move the lens holder 30 together with the shaft 40 when the piezoelectric element 51 is slowly extended in the optical axis direction OA. On the other hand, when the piezoelectric element 51 is contracted instantaneously, only the shaft 40 moves and the lens holder 30 remains in that position. As described above, the lens holder 30 can be moved in the optical axis direction OA by repeatedly extending and contracting the piezoelectric element 51. As the piezoelectric actuator 50, for example, a known smooth impact drive mechanism is used.

  Next, the spring member 70 will be described with reference to FIG. As shown in FIG. 6, the spring member 70 has one end 71, the other end 72, and a base 73. The spring member 70 is a plate-like spring and has a curved shape. The spring member 70 is formed of, for example, a spring stainless steel strip. The spring member 70 is disposed on the side of the lens holder 30 so as to be along the lens holder 30 (the outer periphery of the body portion 31). The one end portion 71 is located at the second corner portion 11b when viewed from the optical axis direction OA of the lens. The other end portion 72 is located at the first corner portion 11a when viewed from the optical axis direction OA of the lens.

  The one end portion 71 is bifurcated so as to avoid the protruding portion 33a of the lens holder 30, and the tip end has a shape bent to the inside of the curve. The one end portion 71 is attached to the lens holder 30 (body portion 31) by engaging with the spring fixing portion 33b. The other end 72 has a contact surface 72 a facing the inside of the curve, and the contact surface 72 a contacts the outer peripheral surface 41. The other end 72 applies a biasing force to the shaft 40 so that the shaft 40 and the lens holder 30 are brought into contact with each other. The intersection P between the first virtual plane 38a and the second virtual plane 38b is a position where the spring member 70 (the other end 72) and the shaft 40 abut against the lens light when viewed from the optical axis direction OA of the lens. It is substantially located on a straight line connecting the axis Z.

  The base 73 connects the one end 71 and the other end 72. The base 73 has a curved shape. The base 73 has a shape that decreases in width as it approaches the one end 71 and the other end 72, and increases in width as it approaches the central portion that is farthest from the one end 71 and the other end 72. ing. That is, the base 73 has a shape in which the width of the central portion of the base 73 that is likely to generate a large stress is widened, and the width in the vicinity of the one end 71 and the other end 72 is smaller than that of the central portion of the base 73. ing.

  As shown in FIG. 4, the regulating member 80 has a cylindrical shape, and is formed of, for example, a stainless steel wire. The restricting member 80 is inserted into the hole 34c and the hole 34d formed in the protruding portions 34a and 34b. The restriction member 80 is disposed on the opposite side of the lens holder 30 with respect to the spring member 70. The outer peripheral surface 81 of the regulating member 80 contacts the base 73 of the spring member 70 when the spring member 70 moves in a direction away from the lens holder 30.

  The position detection unit includes a magnet 91 and a magnetic detection element 92. As shown in FIG. 4, the magnet 91 has a substantially rectangular parallelepiped shape and is fixed to the third protruding portion 35. The magnet 91 is located on the side opposite to the spring member 70 with respect to the lens holder 30. The magnet 91 is formed by a neodymium magnet, for example.

  The magnetic detection element 92 is composed of, for example, a Hall element, and is attached to the flexible substrate 60 as shown in FIG. The magnetism detecting element 92 is arranged to be separated from the magnet 91 so as to face the magnet 91. The magnetic detection element 92 detects the change in the strength of the magnetic field formed by the magnet 91 when the lens holder 30 moves in the optical axis direction OA of the lens, and detects the position of the lens holder 30.

  Next, the biasing force that acts on the lens holder 30 and the shaft 40 from the spring member 70 will be described with reference to FIG. FIG. 7 is a schematic diagram for explaining the biasing force acting from the spring member. FIG. 7 is a schematic diagram to the last, and is not a diagram that accurately shows the position of a force application point.

  The other end 72 of the spring member 70 contacts the shaft 40 at one location. Actually, the other end 72 and the shaft 40 are in line contact. The other end 72 of the spring member 70 applies an urging force A toward the optical axis Z of the lens to the shaft 40. That is, in this embodiment, the urging force A is applied to the shaft 40 in the direction X that connects the other end 72 and the optical axis Z. When the urging force A is applied, the shaft 40 contacts the first and second contact portions 36 and 37 and presses the first and second contact portions 36 and 37, respectively.

  The pressing forces B and C are applied to the lens holder 30 from the first and second contact portions 36 and 37, respectively. The pressing forces B and C generate a resultant force D in the direction X. In the present embodiment, the contact state between the shaft 40 and the first and second contact portions 36 and 37 is appropriately maintained. Therefore, the resultant force D in the X direction with the pressing forces B and C is approximately the same as the urging force A. Since the one end 71 of the spring member 70 receives the resultant force D from the X direction, a similar reaction force E is applied to the lens holder 30 in the direction opposite to the X direction. In this way, a force from both sides of the one end portion 71 and the other end portion 72 of the spring member 70 toward the optical axis Z of the lens is applied to the lens holder 30.

  Next, with reference to FIGS. 8 and 9, the operation and effect of the lens driving device 1 according to the present embodiment will be described in comparison with the lens driving device 100 according to the comparative example. Specifically, the driving state of the lens driving devices 1 and 100, that is, the vibration state of the lens holders 30 and 130 when the lens holders 30 and 130 are moved will be described.

  FIG. 8 is a schematic diagram for explaining a driving state of the lens driving device according to the present embodiment. (A) of FIG. 8 is the schematic diagram which looked at the lens drive device 1 from the optical axis direction OA. (B) in FIG. 8 is a schematic view of the lens driving device 1 as viewed from a direction orthogonal to the optical axis direction OA. In (a), illustration of the cover 20 and the like is omitted. In (b), illustration of the base 10 and the cover 20 is omitted. FIG. 9 is a schematic diagram for explaining a driving state of the lens driving device according to the comparative example. FIG. 9A is a schematic view of the lens driving device 100 viewed from the optical axis direction OA. (B) in FIG. 9 is a schematic view of the lens driving device 100 viewed from a direction orthogonal to the optical axis direction OA. In (a), illustration of a cover etc. is omitted. In (b), illustration of a base, a cover, etc. is omitted.

  When the piezoelectric actuator 50 applies driving force to the shaft 40, the lens holder 30 moves in the optical axis direction OA of the lens. The lens holder 30 vibrates in the optical axis direction OA as shown in (b) of FIG. 8 by the inertial force generated in the lens holder 30 when the movement is started and when the movement is stopped. Since the lens holder 30 is pressed against the shaft 40 by the spring member 70, a frictional force is generated between the lens holder 30 (first and second contact portions 36 and 37) and the shaft 40. For this reason, with the portion on the shaft 40 side (the portion on the first corner portion 11a side) of the lens holder 30 as a fulcrum, the portion (the portion on the second corner portion 11b side) away from the shaft 40 of the lens holder 30 vibrates (shakes). Move). In this embodiment, since the lens holder 30 is applied with a force from both sides of the one end portion 71 and the other end portion 72 of the spring member 70 toward the optical axis Z of the lens, the vibration of the lens holder 30 is suppressed. The

  In the lens driving device 100 according to the comparative example, the end 171 of the spring member 170 forms a predetermined angle α (in this comparative example, α = 45 °), not in the direction toward the optical axis Z of the lens. A biasing force J is applied to the shaft 140 in the direction. The contact portions 136 and 137 of the lens holder 130 each have a flat surface that contacts the shaft 140. A virtual plane including the plane of the contact portion 136 and a virtual plane including the plane of the contact portion 137 intersect each other. When viewed from the optical axis direction OA of the lens, the intersection of these virtual planes is substantially located on a virtual straight line extending from the contact portion between the end 171 and the shaft 140 in the direction in which the biasing force J is applied.

  The shaft 140 is pressed against the lens holder 130 by the biasing force from the spring member 170. The direction in which the shaft 140 is pressed against the lens holder 130 is the direction in which the imaginary straight line extends when viewed from the optical axis direction OA of the lens. That is, in this comparative example, unlike the present embodiment, no force is applied to the lens holder 130 from the spring member 170 toward the optical axis Z of the lens. For this reason, in the lens driving device 100 according to the comparative example, it is difficult to suppress the vibration of the lens holder 130 as compared with the present embodiment.

  As described above, in the present embodiment, the lens holder 30 is in contact with the shaft 40 at the two locations of the first and second contact portions 36 and 37. For this reason, the other end part 72 of the spring member 70 should just contact | abut with respect to the shaft 40 at one place. Therefore, the other end portion 72 of the spring member 70 is appropriately brought into contact with the shaft 40, and the urging force A acting from the other end portion 72 is applied to the shaft 40 at a desired value and in a desired direction. Since the urging force A is applied to the shaft 40 at a desired value and in a desired direction, the shaft 40 and the first and second abutting portions 36 and 37 abut properly. Therefore, the biasing force A is appropriately transmitted to the lens holder 30 as the resultant force D from the first and second contact portions 36 and 37 via the shaft 40 and the first and second contact portions 36 and 37. . One end portion 71 of the spring member 70 is positioned at the second corner portion 11b when viewed from the optical axis direction OA of the lens held by the lens holder 30. For this reason, the reaction force acting on the lens holder 30 is applied to the lens holder 30 from a position facing the urging force A (the resultant force D). That is, a force toward the optical axis Z of the lens is applied to the lens holder 30 from both one end 71 and the other end 72 of the spring member 70. As a result, the vibration of the lens holder 30 can be effectively suppressed.

  In the present embodiment, the first virtual plane 38a and the second virtual plane 38b intersect each other on the inner side of the barrel 31 than the outer peripheral surface 31a of the barrel 31 when viewed from the optical axis direction OA of the lens. . Thereby, since the outer peripheral surface of the trunk | drum 31 can be brought closer to the shaft 40, the trunk | drum 31 which can enlarge the outer diameter and internal diameter of the trunk | drum 31 is attained. If the inner diameter of the body 31 can be enlarged, a lens having a larger aperture can be held in the lens holder 30.

  In the present embodiment, the magnet 91 for detecting the position of the lens holder 30 in cooperation with the magnetic detection element 92 is located on the opposite side of the lens member 30 from the spring member 70. As a result, the spring member 70 is positioned on the side of the third triangular portion 11c with respect to the imaginary line so as to connect the one end portion 71 and the other end portion 72 of the spring member 70, and the magnet 91 is positioned on the fourth square portion 11d side. Therefore, in the mass system including the lens holder 30, the spring member 70, and the magnet 91, mass imbalance with respect to the imaginary line is reduced. Thereby, the vibration of the lens holder 30 can be more reliably suppressed.

  In the present embodiment, the regulating member 80 is disposed on the opposite side of the lens holder 30 with respect to the spring member 70, and the regulating member 80 regulates the movement of the spring member 70 in the direction away from the lens holder 30. Yes. Thereby, the spring member 70 is prevented from being detached from the lens holder 30 and the shaft 40, and the urging force A of the spring member 70 is appropriately applied to the shaft 40. Thereby, the vibration of the lens holder 30 can be more reliably suppressed.

  In the present embodiment, a hemispherical spherical portion 33c is disposed in the first projecting portion. Accordingly, even when the lens holder 30 rotates with the central axis of the shaft 40 as the rotation axis, the spherical portion 33c contacts the second side wall portion 12b, and therefore the rotation of the lens holder 30 can be suppressed.

  As mentioned above, although embodiment of this invention has been described, this invention is not necessarily limited to embodiment mentioned above, A various change is possible in the range which does not deviate from the summary.

  In the present embodiment, the one end portion 71 of the spring member 70 is located at the second corner portion 11b when viewed from the optical axis direction OA of the lens. 11c. If the biasing force A of the other end 72 is directed toward the optical axis Z of the lens, the vibration of the lens holder 30 can be effectively suppressed.

  The lens driving device 1 may not include the sliders 36b and 37b. In this case, each protrusion 36a, 37a directly contacts the shaft 40. Each slider 36b, 37b may have only the first portion.

  The angle θ formed by the first virtual plane 38a and the second virtual plane 38b is not necessarily 90 °, and may be an angle other than 90 ° (for example, θ = 60 °). In this case, the other end portion 72 of the spring member 70 and the first and second contact portions 36 and 37 are arranged at equal intervals every 120 ° with respect to the shaft. In this arrangement, the force acting on the shaft 40 from the other end 72 of the spring member 70 is a plane (abutting surface) of the magnitude in the direction perpendicular to the abutting surface 72a and the force acting on the shaft 40 from the slider 36b. ) The size of 36c in the direction perpendicular to the surface is equal to the size of the force acting on the shaft 40 from the slider 37b in the direction perpendicular to the plane of the flat surface (contact surface) 37c. Therefore, when the friction coefficient between the shaft 40 and each member (the other end portion 72, the slider 36b, and the slider 37b) is equal, the friction force and the vertical drag force between the shaft 40 and each member are equal, and each member is Therefore, the force acting on the shaft 40 is balanced on the central axis of the shaft 40. As a result, the transmission efficiency of the driving force applied from the piezoelectric actuator 50 to the shaft 40 to the lens holder 30 is improved, and the vibration of the lens holder 30 can be further suppressed.

DESCRIPTION OF SYMBOLS 1 ... Lens drive device, 10 ... Base, 11a ... 1st corner | angular part, 11b ... 2nd corner | angular part, 11c ... 3rd triangle part, 11d ... 4th corner | angular part, 30 ... Lens holder, 31 ... trunk | drum, 31a ... outer periphery 36, first contact portion, 37 ... second contact portion, 36c, 37c ... plane, 38a ... first virtual plane, 38b ... second virtual plane, 40 ... shaft, 50 ... piezoelectric actuator, 70 ... spring 71, one end portion, 72, the other end portion, 80, a regulating member, 91, a magnet, 92, a magnetic detection element, Z, an optical axis, OA, an optical axis direction.

Claims (4)

A base that has a rectangular shape in plan view, and has a first and second corners that are diagonal to each other and a third and fourth corners that are diagonal to each other;
A shaft disposed at the first corner,
A lens holder disposed on the base so as to abut against the shaft and holding a lens;
A piezoelectric actuator that is disposed at the first corner and applies a driving force to the shaft so as to move the lens holder in the optical axis direction of the lens held by the lens holder;
The lens holder is disposed on the side of the lens holder and has one end fixed to the lens holder and the other end abutting on the shaft, and the shaft and the lens holder. A spring member that applies a biasing force to the shaft from the other end so as to abut,
The lens holder has a cylindrical barrel portion, and first and second contact portions each having a plane located on the outer peripheral surface of the barrel portion and abutting against the shaft,
The one end of the spring member is located between the second corner to the third triangle when viewed from the optical axis direction of the lens held by the lens holder,
The lens driving device, wherein the other end portion of the spring member is in contact with the shaft so that the urging force is directed toward an optical axis of a lens held by the lens holder.   The first virtual plane including the plane of the first contact portion and the second virtual plane including the plane of the second contact portion are viewed from the optical axis direction of the lens held by the lens holder. 2. The lens driving device according to claim 1, wherein the lens driving device sometimes intersects the inner side of the body part with respect to the outer peripheral surface of the body part. A magnet disposed on the lens holder;
A magnetic detection element disposed apart from the magnet so as to face the magnet, and
The lens driving device according to claim 1, wherein the magnet is located on the opposite side of the lens holder from the spring member.   The control member according to any one of claims 1 to 3, further comprising a restricting member that is disposed on a side opposite to the lens holder with respect to the spring member and restricts movement of the spring member in a direction away from the lens holder. The lens driving device described.

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