JP5323528B2 - Lens drive device - Google Patents

Description

  The present invention relates to a lens driving device in which a moving body including a lens is supported by a spring member so as to be displaceable in an optical axis direction.

  A camera mounted on a camera-equipped mobile phone, a digital camera, or the like has a lens driving device that drives the lens to be displaced in the optical axis direction. Such a lens driving device has a moving body provided with a lens and a support body on which the moving body is mounted via one or more spring members, and drives the moving body by a magnetic drive mechanism. The spring member includes a support side fixing portion that is fixed to the support side, a moving body side fixing portion that is fixed to the moving body side, and a plurality of arm portions that couple the support side fixing portion and the moving body side fixing portion. Such a spring member is generally manufactured by subjecting a thin plate to a wet etching process or a press process using a photolithography technique (see Patent Document 1).

JP 2006-201525 A

  In the lens driving device described above, the degree of freedom in design of the spring member has been reduced with downsizing of the lens driving device. For example, if the arm portion is thickened, the spring constant can be increased accordingly, but if the lens driving device is downsized, the space around the moving body is narrowed, so it is difficult to thicken the arm portion. . If the thickness of the spring member is increased, the spring constant can be increased. However, if the spring member is increased in thickness, the arm width is affected by side etching during wet etching and burrs during pressing. The accuracy of dimensions and shapes is reduced. Furthermore, regarding the spring member, it is desired to support the moving body evenly in all directions, and for this purpose, it is necessary to perform a design with an increased number of arm portions or a design in which the arm portions are routed in a complicated manner. However, when the space around the moving body is reduced with the miniaturization of the lens driving device, such a design becomes difficult.

  In view of the above problems, an object of the present invention is to provide a lens driving device that can increase the degree of freedom of design for a spring member even if there is a restriction such as a narrow space around a moving body. It is in.

In order to solve the above-described problems, in the present invention, a moving body provided with a lens, a supporting body that supports the moving body, one or more spring members that are connected to the supporting body and the moving body, and the movement And a magnetic drive mechanism that magnetically drives the body, wherein at least one of the one or more spring members includes a support-side fixing portion that is fixed to the support side, and a movement that is fixed to the movable body side. A plurality of plate springs each including a body side fixing portion and an arm portion connecting the support body side fixing portion and the movable body side fixing portion are stacked, and the plurality of plate springs are adjacent in the optical axis direction. In the plate spring, the shape of the arm portion is different, and the longitudinal spring constant of the plate spring located on the subject side is smaller than the longitudinal spring constant of the plate spring located on the side opposite to the subject side. It is characterized by that.

  The lens driving device according to the present invention includes a support-side fixing portion that is fixed to the support side, a moving-body-side fixing portion that is fixed to the moving-body side, and an arm portion that connects the support-side fixing portion and the moving-body-side fixing portion. Unlike the case where a single plate spring is used to form a spring member, a configuration in which the width of the arm is narrow and the thickness of the arm are different because a spring member made up of a plurality of plate springs is used. The spring constant is large even in a thin structure. Also, since a single plate-like spring may be thin, even when a spring member is manufactured by wet etching or pressing, side etching effects and burrs are less likely to occur. High accuracy. Furthermore, since one spring member is constituted by a plurality of plate springs, a configuration in which the shape of the arm portion is made different for each plate spring, a configuration in which plate springs having the same arm shape are stacked in the same direction The degree of freedom in designing the spring member is extremely high, such as a configuration in which plate springs having the same arm shape are stacked in different directions.

  In the present invention, it is preferable that the plate springs adjacent to each other in the lens optical axis direction of the plurality of plate springs are not joined at any position. According to such a configuration, since each arm portion of the plurality of plate springs functions independently, the spring constant can be easily set.

  In the present invention, it is preferable that an angular direction in which the movable body is easily displaced in a direction perpendicular to the lens optical axis direction is shifted between the plurality of plate springs. According to such a configuration, the moving body can be prevented from being displaced in a specific direction around the lens optical axis direction.

  In the present invention, the plurality of plate-like springs are arranged such that angular directions where the movable body is likely to be displaced in a direction orthogonal to the lens optical axis direction are alternately and equiangularly spaced around the lens optical axis. It is preferable. According to such a configuration, it is possible to more reliably avoid displacement of the moving body in a specific direction around the lens optical axis direction.

In the present invention, it is preferable that at least a part of the arm portions of the plurality of plate springs adjacent to each other in the lens optical axis direction are in contact with each other in the lens optical axis direction. According to such a configuration, when the moving body is about to be displaced, the frictional force applied when the arms slide is applied to the moving body, so that the moving body is displaced in the direction perpendicular to the lens optical axis direction. It can be surely prevented.

  In the present invention, in the spring member, it is preferable that the number of the plate springs is two. If the number of plate springs is two, it is possible to sufficiently meet the demands required of the spring member in the lens driving device, and it is possible to reduce the cost compared to the case where three or more plate springs are used.

  The lens driving device according to the present invention includes a support-side fixing portion that is fixed to the support side, a moving-body-side fixing portion that is fixed to the moving body side, and an arm portion that couples the support-side fixing portion and the moving body-side fixing portion. Unlike the case where a single plate spring is used to form a spring member, a configuration in which the width of the arm is narrow and the thickness of the arm are different because a spring member made up of a plurality of plate springs is used. The spring constant is large even in a thin structure. Also, since a single plate-like spring may be thin, even when a spring member is manufactured by wet etching or pressing, side etching effects and burrs are less likely to occur. High accuracy. Furthermore, since one spring member is constituted by a plurality of plate springs, a configuration in which the shape of the arm portion is made different for each plate spring, a configuration in which plate springs having the same arm shape are stacked in the same direction The degree of freedom in designing the spring member is extremely high, such as a configuration in which plate springs having the same arm shape are stacked in different directions.

(A), (b) is the external view which looked at the lens drive device to which this invention is applied from diagonally upward, and an exploded perspective view, respectively. The operation of the lens driving equipment shown in FIG. 1 is an explanatory view schematically showing. (A), (b), (c) is a plan view of a spring member used for the lens driving device according to Embodiment 1 of the present invention, and of the two plate springs used for this spring member, FIG. 4 is a plan view of an upper plate spring and a plan view of a lower plate spring. (A), (b) is the top view of the upper plate-shaped spring used for the spring member of the lens drive device which concerns on the reference example of this invention, respectively, and the top view of a lower plate-shaped spring. (A), (b) is the top view of the upper plate-shaped spring used for the spring member of the lens drive device which concerns on Embodiment 2 of this invention, respectively, and the top view of a lower plate-shaped spring. (A), (b), (c) is a plan view of a spring member used for the lens driving device according to Embodiment 3 of the present invention, and of the two plate springs used for this spring member, FIG. 4 is a plan view of an upper plate spring and a plan view of a lower plate spring.

  The best mode for carrying out the present invention will be described below with reference to the drawings. The lens driving device described below can be attached to various electronic devices in addition to the camera-equipped mobile phone. For example, it can be used for a thin digital camera, PHS, PDA, bar code reader, surveillance camera, camera for checking the back of a car, a door having an optical authentication function, and the like. In the following description, the directions perpendicular to each other are described as the X direction, the Y direction, and the Z direction, and the direction along the optical axis is described as the Z direction. In the following description, for convenience of explanation, the subject side is shown as “up / front side” as the + Z direction, and the image side (side where the image sensor is arranged) is shown as “down / rear side” in the −Z direction.

[Embodiment 1]
(Entire configuration of lens driving device)
FIGS. 1A and 1B are an external view and an exploded perspective view, respectively, of the lens driving device according to Embodiment 1 of the present invention viewed obliquely from above.

  1A and 1B, a lens driving device 1 according to the present embodiment is a thin camera used for a camera-equipped mobile phone or the like. For example, three lenses 121 are arranged along a lens optical axis direction L as a subject (object). For moving in the A direction (front side) approaching the side) and the B direction (rear side) approaching the side opposite to the subject (image side), and has a substantially rectangular parallelepiped shape. The lens driving device 1 generally includes a moving body 3 that holds a cylindrical lens holder 12 that includes three lenses 121 and a fixed aperture (not shown) on the inside, and the moving body 3 in the optical axis direction L. It has a lens driving mechanism 5 that moves along, and a support 2 on which the lens driving mechanism 5 and the moving body 3 are mounted. The moving body 3 includes a cylindrical sleeve 13, and a cylindrical lens holder 12 is fixed to the inside thereof. Therefore, the outer shape of the moving body 3 is defined by the sleeve 13 and has a substantially cylindrical shape.

  The support 2 includes a rectangular holder 19 for holding an image sensor (not shown) on the image side, a box-shaped yoke 18 positioned on the subject side, and a rectangular frame-shaped spacer 11. In the center of the top plate portion 185 of the yoke 18 and the spacer 11, circular incident windows 110 and 180 for taking light from the subject into the lens 121 are formed. The yoke 18 is made of a ferromagnetic plate such as a steel plate, and constitutes a linkage magnetic field generator 4 that generates a linkage magnetic field in the drive coil 30 held by the sleeve 13 together with the magnet 17 as will be described later.

  The lens driving mechanism 5 includes a drive coil 30 wound around the outer peripheral surface of the sleeve 13 and a linkage magnetic field generator 4 that generates a linkage magnetic field in the drive coil 30. The drive coil 30 and the linkage magnetic field generator 4 constitutes a magnetic drive mechanism 5a. The interlinkage magnetic field generator 4 includes four magnets 17 that face the drive coil 30 on the outer peripheral side. The yoke 18 is also used as a component of the interlinkage magnetic field generator 4.

  The yoke 18 has a box shape that covers the side surface and the upper surface of the drive coil 30, and can reduce leakage magnetic flux from a magnetic path formed between the magnet 17 and the drive coil 30. The linearity between the amount of movement of the sleeve 13 and the current passed through the drive coil 30 can be improved. In the yoke 18, the pair of side surfaces 181 facing each other is formed in a flat shape, and the other pair of side surfaces 182 facing each other protrudes outwardly in a stepped manner at the center because both ends 182 a are recessed inward. A convex portion 182b is formed.

  In this embodiment, each of the four magnets 17 has a substantially triangular prism shape, and is fixed to the four corners of the inner peripheral surface of the yoke 18 in a state of being separated in the circumferential direction. Each of the four magnets 17 is divided into two in the optical axis direction, and in any case, the inner surface and the outer surface are magnetized to different poles. In the four magnets 17, for example, the inner surface is magnetized to the N pole in the upper half, the outer surface is magnetized to the S pole, and the inner surface is magnetized to the S pole in the lower half, and the outer surface is magnetized to the N pole. It is magnetized. Therefore, the drive coil 30 is divided into two corresponding to the upper half and the lower half of the magnet 17, and the winding direction of the divided drive coil is opposite. As described above, if the magnet 17 is divided into four corners, a thin portion is generated in the magnet 17 even when the gap between the yoke 18 and the sleeve 13 is narrow in the central portion of the side portion of the yoke 18. This can be prevented, the strength of the magnet 17 can be increased, and the magnetic force of the magnet 17 can be efficiently applied to the drive coil 30 mounted on the moving body 3. In addition, by effectively using the four corner spaces between the moving body 3 and the yoke 18 as the arrangement space for the magnets 17, the entire lens driving device 1 can be reduced in size.

  The lens driving mechanism 5 further includes a ring-shaped magnetic piece 130 held at the upper end of the sleeve 13, and such a magnetic piece 130 is applied to the moving body 3 by an attractive force acting between the magnet 17. On the other hand, an urging force in the optical axis direction is applied. For this reason, since it is possible to prevent the mobile body 3 from being displaced by its own weight when no current is applied, it is possible to maintain the mobile body 3 in a desired posture and to further improve the impact resistance. Further, the magnetic piece 130 acts as a kind of back yoke, and can reduce the leakage magnetic flux from the magnetic path formed between the magnet 17 and the drive coil 30. In addition, as a magnetic piece, a rod-shaped magnetic body may be used.

  The lens driving device 1 of the present embodiment further includes spring members 14x and 14y between the holder 19 and the sleeve 13 and between the spacer 11 and the sleeve 13, respectively. Both of the two spring members 14x and 14y are made of metal such as beryllium copper or SUS steel, and are formed by pressing a thin plate having a predetermined thickness or etching using a photolithography technique.

  Although the detailed configuration of the spring members 14x and 14y will be described later, the lower spring member 14x is connected to the holder 19 and the sleeve 13, and the movable body 3 is moved to the support body 2 so as to be movable along the lens optical axis. The state is supported. The upper spring member 14y is connected to the spacer 11 and the sleeve 13, and the movable body 3 is supported by the support body 2 so as to be movable along the lens optical axis.

  Of the spring members 14x and 14y, the spring member 14x disposed on the holder 19 side is divided into two spring pieces 14a and 14b, and the winding start end and the winding end end of the drive coil 30 are respectively spring pieces. 14a and 14b. In the spring member 14 x, terminals 12 c are formed on the spring pieces 14 a and 14 b, respectively, and the spring member 14 x (spring pieces 14 a and 14 b) also functions as a power supply member for the drive coil 30.

  The spacer 11 is attached to the inner surface of the top plate portion 185 of the yoke 18 and has a rectangular frame portion 115 in which an incident window 110 is formed at the center. At the four corners of the rectangular frame portion 115, small projections 112 protruding toward the image sensor are formed. The holder 19 also has small protrusions 192 extending toward the subject at its four corners. The small protrusion 192 of the holder 19 and the small protrusion 112 of the spacer 11 are used when connecting the two spring members 14x and 14y to the support body 2, respectively.

  Projections 13a and 13b projecting toward the outer peripheral side are formed on the outer peripheral surface of the sleeve 13, and the protrusions 13a and 13b are arranged in the lens optical axis direction L at both side positions sandwiching the lens 121 (lens holder 12). It protrudes in a direction perpendicular to the direction. When the sleeve 13 (moving body 3) configured in this way is arranged in the support 2, the protrusions 13 a and 13 b are arranged inside the convex portion 182 b of the yoke 18 between the adjacent magnets 17. Here, the convex portion 182b extends in the optical axis direction, and the convex portion 182b allows the movement of the protrusions 13a and 13b in the optical axis direction when the moving body 3 moves in the optical axis direction. Function as. Further, when the moving body 3 is displaced in a direction (right and left direction or circumferential direction) perpendicular to the optical axis direction due to an impact or the like, the protrusions 13a and 13b come into contact with the inner wall of the convex portion 182b of the yoke 18, so that the movement further takes place. Displacement in the left-right direction orthogonal to the optical axis direction of the body 3 and rotational displacement in the circumferential direction can be prevented.

  A plurality of small protrusions 13y for connecting the spring member 14y are formed in the circumferential direction on the upper end surface (the subject-side end surface) of the sleeve 13, and on the lower end surface (the end surface on the image sensor side) of the sleeve 13. Has a plurality of small protrusions 13x for connecting the spring member 14x in the circumferential direction.

(Basic operation)
FIG. 2 is an explanatory diagram schematically showing the operation of the lens driving device 1 shown in FIG. The left half of FIG. 2 shows a view when the sleeve 13 is at an infinite position (normal photographing position), and the right half of FIG. 2 is that the sleeve 13 is at a macro position (close-up photographing position). Figure shows when.

  As shown in FIG. 2, the moving body 3 is normally located on the image sensor side (image side). When a current in a predetermined direction is passed through the drive coil 30 in such a state, the drive coil 30 is Each receives an upward (front) electromagnetic force. Thereby, the sleeve 13 to which the drive coil 30 is fixed starts to move toward the subject side (front side). At this time, elastic forces that restrict the movement of the sleeve 13 are generated between the spring member 14y and the front end of the sleeve 13 and between the spring member 14x and the rear end of the sleeve 13, respectively. For this reason, when the electromagnetic force that attempts to move the sleeve 13 to the front side and the elastic force that restricts the movement of the sleeve 13 are balanced, the sleeve 13 stops. At that time, the sleeve 13 (moving body 3) can be stopped at a desired position by adjusting the amount of current flowing through the drive coil 30 according to the elastic force acting on the sleeve 13 by the spring members 14x and 14y. In this embodiment, since the spring members 14x and 14y in which a linear relationship is established between the elastic force (stress) and the displacement amount (strain amount) are used, the amount of movement of the sleeve 13 and the current flowing through the drive coil 30 are Linearity can be improved. Further, since the two spring members 14x and 14y are used, a large balance force is applied in the lens optical axis direction L when the sleeve 13 is stopped, and centrifugal force and impact force are applied in the lens optical axis direction L. Even if other forces such as these work, the sleeve 13 can be stopped more stably. Furthermore, in the lens driving device 1, the sleeve 13 is not stopped by colliding with a collision material (buffer material) or the like, but is stopped using a balance between electromagnetic force and elastic force. It is also possible to prevent the generation of sound.

(Detailed configuration of the spring member 14y)
3A, 3B, and 3C are plan views of the spring member 14y used in the lens driving device 1 according to Embodiment 1 of the present invention, respectively, and the two plates used in the spring member 14y. It is a top view of an upper plate-shaped spring among planar springs, and a plan view of a lower plate-shaped spring.

  As shown in FIG. 3 (a), the spring member 14y of this embodiment is formed by overlapping the upper plate spring 14s shown in FIG. 3 (b) and the lower plate spring 14t shown in FIG. 3 (c). Combined. Each of the plate springs 14s and 14t is formed by wet etching using a photolithography technique or press working on a thin metal plate made of a copper alloy or the like.

  In the spring member 14y, the upper plate spring 14s includes a rectangular frame-shaped support side fixing portion 149s fixed to the support 2 (spacer 11) and an annular shape fixed to the moving body 3 (sleeve 13). The movable body side fixing portion 148s, and four plate-like spring-like arm portions 140s that connect the supporting body side fixing portion 149s and the moving body side fixing portion 148s are provided. The four arm portions 140s are arranged rotationally symmetrically and are formed at 90 ° intervals in the circumferential direction. A small hole 147s into which the small protrusion 112 of the spacer 11 is fitted is formed in each of the four corner portions in the support side fixing portion 149s. Further, in the outer peripheral edge of the movable body side fixing portion 148s, notches 146s recessed inward in the radial direction are formed in each of the portions facing the four side portions of the supporting body side fixing portion 149s.

  Similarly to the upper plate spring 14s, the lower plate spring 14t is also fixed to the rectangular frame-shaped support body side fixing portion 149t fixed to the support body 2 (spacer 11) and the movable body 3 (sleeve 13). An annular moving body side fixing portion 148t, and four plate-like spring-like arm portions 140t that connect the supporting body side fixing portion 149t and the moving body side fixing portion 148t. The four arm portions 140t are arranged rotationally symmetrical and are formed at 90 ° intervals in the circumferential direction. A small hole 147t into which the small protrusion 112 of the spacer 11 is fitted is formed in each of the four corner portions in the support side fixing portion 149t. Further, in the outer peripheral edge of the movable body side fixing portion 148t, notches 146t recessed inward in the radial direction are formed in each of the portions facing the four side portions of the supporting body side fixing portion 149t.

  When the plate-like springs 14s and 14t having such a configuration are used as the spring member 14y in the lens driving device 1, the small protrusion 112 of the spacer 11 is fitted into the small holes 147s and 147t of the plate-like springs 14s and 14t, and the support-side fixing portion. After positioning 149s, 149t and the spacer 11, the support-side fixing portions 149s, 149t and the spacer 11 are fixed by a method such as applying and curing an adhesive in the small holes 147s, 147t. The small protrusion 13y of the sleeve 13 is fitted into the notches 146s and 146t of the plate springs 14s and 14t to position the movable body side fixing portions 148s and 148t and the sleeve 13, and then the notches 146s and 146t. The movable body side fixing portions 148s and 148t and the sleeve 13 are fixed by a method such as applying and curing an adhesive.

  As a result, the plate springs 14s and 14t are overlapped in a close state. Therefore, the arm portion 140s of the plate spring 14s and the arm portion 140t of the plate spring 14t are overlapped with each other. However, the arm portion 140s of the plate spring 14s and the arm portion 140t of the plate spring 14t are not joined at all.

  In the spring member 14y configured as described above, in the plate springs 14s and 14t, the support side fixing portions 149s and 149t have substantially the same configuration, and the moving body side fixing portions 148s and 148t also have substantially the same configuration. doing.

  However, the configuration of the arm part 140s and the arm part 140t is different. First, the arm portion 140s of the plate spring 14s is meandering in the radial direction while meandering from the connecting portion with the movable body side fixed portion 148s, and extending in the circumferential direction from the meandering portion 141s. A folding portion 142s that folds back and a meandering portion 143s that extends in the circumferential direction while meandering in the radial direction from the folded portion 142s to the connecting portion of the support side fixing portion 149s.

  On the other hand, the arm portion 140t of the plate spring 14t includes a meandering portion 141t extending in the circumferential direction while meandering in the radial direction from a connecting portion with the movable body side fixed portion 148t, and extending in the circumferential direction from the meandering portion 141t. It is provided with a folded portion 142t that is folded back and reaches the connecting portion with the support side fixing portion 149t.

  Comparing the plate springs 14s and 14t having such a configuration, the plate spring 14s has two meandering portions 141s and 143s, and has a small transverse spring constant, but has a meandering portion, so that the lens light is reduced. This has the advantage that the longitudinal spring constant is constant over a wide deformation range in the axial direction L. On the other hand, the plate spring 14t has only one meandering portion 141t, and thus has a small range in which the longitudinal spring constant in the lens optical axis direction L is constant, but has an advantage that the lateral spring constant is large. . Therefore, according to the present embodiment, it is possible to satisfy the requirement that the lateral spring constant is large and the requirement that the longitudinal spring constant is constant over a wide range in the lens optical axis direction L. In this embodiment, the plate spring 14s having a small longitudinal spring constant is arranged on the subject side in the lens optical axis direction L from the plate spring 14t. Therefore, when the movable body 3 moves to the subject side, the arm portions 140s and 140t are moved. There is an advantage of not preventing mutual deformation.

(Main effects of this form)
As described above, in the lens driving device 1 of the present embodiment, the spring member 14y in which the two plate springs 14s and 14t are overlapped is used, and therefore, the spring member 14y is configured by one plate spring. In contrast, the spring constant is large even when the width of the arm portions 140s and 140t is narrow or the thickness of the arm portions 140s and 140t is thin. That is, assuming that the spring constant, longitudinal elastic modulus, width dimension, plate thickness, and length dimension of the arm portions 140s and 140t are k, E, b, t, and a, respectively, these are the following relationships: k = E · b · t ^3/4 · a ³
Since the spring constant k can be increased by increasing the width and thickness of the arm portions 140s and 140t, in this embodiment, the two plate springs 14s and 14t are used. The spring constant of the spring member 14y is increased. For this reason, since it is not necessary to increase the width dimension of the arm portions 140s and 140t, even when the space around the moving body 3 is narrow due to downsizing of the lens driving device 1 or the like, the spring member 14y ( The arm portions 140s, 140t of the plate springs 14s, 14t) can be arranged. Further, since the single plate springs 14s and 14t may be thin, even when manufactured by wet etching, they are not easily affected by side etching. Therefore, the accuracy of the width dimension and shape of the arm portions 140s and 140t of the spring member 14y (plate springs 14s and 14t) is high.

  In addition, since one spring member 14y is configured by the two plate springs 14s and 14t, the shape of the arm portions 140s and 140t is made different for each plate spring to optimize the spring constant as in this embodiment. The degree of freedom of design for the spring member 14y is extremely high.

  Further, in the present embodiment, the arm portions 140s and the arm portions 140t are not joined at any place in the plate springs 14s and 14t. For this reason, since each arm part 140s and 140t function independently, the setting of a spring constant is easy. Further, the arm portion 140s and the arm portion 140t are not joined at any point, but are in contact with each other in the lens optical axis direction L. For this reason, when the moving body 3 is about to be displaced, a frictional force applied when the arm portion 140s and the arm portion 140t slide is applied to the moving body 3, so that the moving body 3 is orthogonal to the lens optical axis direction L. Can be more reliably prevented.

  Furthermore, in this embodiment, the spring member 14y is composed of two plate springs 14s and 14t. If the number of plate springs is two, the lens drive device 1 requires the spring member 14y. The cost can be reduced compared to the case of using three or more plate springs.

[ Reference example ]
4A and 4B are a plan view of an upper plate spring used for the spring member 14y of the lens driving device 1 according to the reference example of the present invention, and a plan view of the lower plate spring, respectively. is there. Since the basic configuration of this embodiment is the same as that of Embodiment 1, common portions are denoted by the same reference numerals and description thereof is omitted.

  Also in this embodiment, the spring member 14y shown in FIG. 1 includes the upper plate spring 14s shown in FIG. 4A and the lower plate spring 14t shown in FIG. Are superimposed. The plate springs 14s and 14t are formed by wet etching using a photolithography technique or press working on a thin metal plate made of a copper alloy or the like. In this embodiment, each of the plate springs 14s and 14t is a rectangular frame-shaped support body side fixing portion 149s and 149t, an annular mobile body side fixing portion 148s and 148t, a support body side fixing portion 149s and 149t, and a mobile body side fixing. Four plate-like spring-shaped arm portions 140s and 140t that connect the portions 148s and 148t are provided. The four arm portions 140s and 140t are arranged rotationally symmetrical and are formed at 90 ° intervals in the circumferential direction.

  Here, each of the plate springs 14s and 14t has the configuration described with reference to FIG. 3B, and the support-side fixing portions 149s and 149t have substantially the same configuration, and the movable body side The fixing portions 148s and 148t also have substantially the same configuration.

  The arm portions 140s and 140t have the same configuration. That is, the arm portion 140s includes a meandering portion 141s extending in the circumferential direction while meandering in the radial direction from a connection portion with the movable body side fixed portion 148s, and a folded portion 142s that is folded back while extending in the circumferential direction from the meandering portion 141s. It has. Similarly to the arm portion 140s, the arm portion 140t also folds while meandering from the connecting portion with the movable body side fixed portion 148t while extending in the circumferential direction while meandering in the radial direction and extending from the meandering portion 141t in the circumferential direction. And a folded portion 142t.

  The plate springs 14s and 14t are arranged in the same direction and completely overlap in the lens optical axis direction L. For this reason, the arm portion 140s of the plate spring 14s and the arm portion 140t of the plate spring 14t are overlapped in close contact with each other. However, the arm portion 140s of the plate spring 14s and the arm portion 140t of the plate spring 14t are not joined at all.

  Even in this configuration, the spring member 14y in which the two plate springs 14s and 14t are overlapped is used as in the first embodiment. Therefore, unlike the case where the spring member 14y is constituted by a single plate spring, the spring constant is constant even when the width of the arm portions 140s and 140t is narrow or the thickness of the arm portions 140s and 140t is thin. large. Therefore, since it is not necessary to increase the width dimension of the arm portions 140s and 140t, even when the space around the moving body 3 is narrow due to downsizing of the lens driving device 1 or the like, the spring member 14y (plate) is formed around the moving body 3. Arm portions 140s, 140t of the springs 14s, 14t) can be arranged. In addition, since the single plate springs 14s and 14t may be thin, even when manufactured by wet etching or pressing, the width and shape accuracy of the arm portions 140s and 140t are high, and the like. The effect is almost the same.

  Further, in this embodiment, since the two plate springs 14s and 14t have the same shape, the number of component types can be reduced.

[ Embodiment 2 ]
5A and 5B are a plan view of an upper plate spring used for the spring member 14y of the lens driving device 1 according to Embodiment 2 of the present invention, and a plane of the lower plate spring, respectively. FIG. Since the basic configuration of this embodiment is the same as that of Embodiment 1 , common portions are denoted by the same reference numerals and description thereof is omitted.

  Also in this embodiment, as in the first embodiment, the spring member 14y shown in FIG. 1 includes an upper plate spring 14s shown in FIG. 5A and a lower plate spring 14t shown in FIG. 5B. Are superimposed. The plate springs 14s and 14t are formed by wet etching using a photolithography technique or press working on a thin metal plate made of a copper alloy or the like. In this embodiment, each of the plate springs 14s and 14t is a rectangular frame-shaped support body side fixing portion 149s and 149t, an annular mobile body side fixing portion 148s and 148t, a support body side fixing portion 149s and 149t, and a mobile body side fixing. Four plate-like spring-shaped arm portions 140s and 140t that connect the portions 148s and 148t are provided. The four arm portions 140s and 140t are arranged rotationally symmetrical and are formed at 90 ° intervals in the circumferential direction.

  Here, the plate spring 14s has the same configuration as that described with reference to FIG. 3C, and the arm portion 140s meanders in the radial direction from the connecting portion with the movable body side fixing portion 148s. However, a meandering portion 141s extending in the circumferential direction and a folded portion 142s that folds back while extending in the circumferential direction from the meandering portion 141s are provided.

  The plate spring 14t has substantially the same configuration as the plate spring 14s, but the arm portion 140t of the plate spring 14t is different in direction from the arm portion 140s of the plate spring 14s. More specifically, the arm part 140s is folded back while extending in the circumferential direction from the meandering part 141s and the meandering part 141s extending in the circumferential direction while meandering in the radial direction from the connection part with the movable body side fixed part 148s. The folded portion 142s is provided, but is offset from the arm portion 140t of the plate spring 14t by an angle of about 45 °. For example, the arm portion 140s of the plate spring 14s is located at the corner portion of the support side fixing portion 149s, but the arm portion 140t of the plate spring 14t is located at the side portion of the support side fixing portion 149t. . In the plate spring 14t, a part of the side portion of the support-side fixing portion 149t is cut away from the viewpoint of preventing interference between the arm portion 140t and the support-side fixing portion 149t.

Even when configured in this manner, substantially the same effects as those of the first embodiment can be obtained. Furthermore, in this embodiment, the angle direction in which the movable body 3 is easily displaced in the direction orthogonal to the lens optical axis direction L is shifted between the plate springs 14s and 14t. For example, the plate-like spring 14s is indicated by an arrow S because the arm part 140s supports the moving body 3 in a direction shifted by about 60 ° clockwise CW with respect to the X-direction axis X1 and the Y-direction axis Y1. Furthermore, the moving body 3 has directivity that it is easy to move in a direction shifted by an angle Θ ₁ of about 15 ° clockwise CW with respect to the X-direction axis X1 and the Y-direction axis Y1. On the other hand, the plate-like spring 14t supports the moving body 3 in the direction shifted by about 15 ° clockwise CW with respect to the X-direction axis X1 and the Y-direction axis Y1, and therefore the arrow T As shown, the moving body 3 has directivity that it is easy to move in a direction shifted by an angle Θ ₂ of about 60 ° clockwise CW with respect to the X-direction axis X1 and the Y-direction axis Y1. For this reason, the movable body 3 is supported in a total of eight directions in the circumferential direction by the spring members 14y (plate springs 14s and 14t). In addition, the moving body 3 is supported by a spring member 14y (plate springs 14s and 14t) in a total of eight directions at equiangular intervals in the circumferential direction. For this reason, it is possible to reliably avoid displacement of the moving body 3 in a specific direction around the lens optical axis direction L.

[ Embodiment 3 ]
6 (a), 6 (b), and 6 (c) are plan views of the spring member 14x used in the lens driving device 1 according to Embodiment 3 of the present invention, respectively, and the two plates used for the spring member 14x. It is a top view of an upper plate-shaped spring among planar springs, and a plan view of a lower plate-shaped spring. Since the basic configuration of this embodiment is the same as that of Embodiments 1 and 2, common portions are denoted by the same reference numerals and description thereof is omitted.

In the first and second embodiments, the present invention is applied to the subject-side spring member 14y of the spring members 14x and 14y shown in FIGS. 1 and 2, but the present invention is applied to the imaging-element-side spring member 14x. The invention may be applied.

  Also in such a form, the spring member 14x shown in FIG. 6A overlaps the upper plate spring 14s shown in FIG. 6B and the lower plate spring 14t shown in FIG. 6C. Combined. Since the plate springs 14s and 14t are the same as those in the first embodiment, detailed description thereof is omitted. However, the plate springs 14s and 14t are rectangular frame-shaped fixed to the support 2 (holder 19). The support side fixing portions 149s and 149t, the annular moving body side fixing portions 148s and 148t fixed to the moving body 3 (sleeve 13), and the support side fixing portions 149s and 149t and the moving body side fixing portions 148s and 148t are connected. Four plate-like spring-like arm portions 140s and 140t.

  Here, in the case of the spring member 14x on the imaging element side, the spring member 14x is divided into two spring pieces 14a and 14b because it is used as a power feeding member. For this reason, in the upper plate-like spring 14s, the support body side fixing portion 149s is divided by the slit 144s, and the moving body side fixing portion 148s is divided by the slit 145s. In the lower plate spring 14t, the support-side fixing portion 149t is divided by the slit 144t, and the moving-body-side fixing portion 148t is divided by the slit 145t.

  Even when such a configuration is adopted, until the plate spring 14s is connected to the sleeve 13 or the holder 19, the support-side fixing portion 149s divided by the slit 144s is connected via the frame 14e. The moving body side fixed portion 148s divided at 145s is connected via the connecting plate 14g. Then, after the plate spring 14s is connected to the sleeve 13, the frame 14e and the connecting plate 14g are bent and cut off at the constricted portion. Further, until the plate spring 14t is connected to the sleeve 13 or the holder 19, the support side fixing portion 149t divided by the slit 144t is connected via the frame 14f, and the moving body side fixing divided by the slit 145t. The part 148t is connected via the connecting plate 14h. Then, after connecting the plate spring 14t to the sleeve 13, the frame 14f and the connecting plate 14h are bent and cut off at the constricted portion.

  In adopting this method, when the connecting plates 14g and 14h are compared, the connecting plate 14h is larger than the connecting plate 14g. For this reason, when the plate-like springs 14s and 14t are overlapped and connected to the sleeve 13, the connecting plate 14h projects from the connecting plate 14g as shown in FIG. 6B. Therefore, after the connecting plate 14h is picked and cut, when the connecting plate 14g is picked and cut, it is easy to pick the connecting plate 14h.

(Other embodiments)
In the first and second embodiments , the present invention is applied to the spring member 14y out of the spring members 14x and 14y, and the third embodiment is an example in which the present invention is applied to the spring member 14x. The present invention may be applied to both the members 14x and 14y.

Moreover, although the said Embodiment 1-3 was an example which has two spring members 14x and 14y, it is this invention to the lens drive device 1 which has one or three or more spring members. May be applied.

Further, in the first to third embodiments , the present invention is applied to the spring members 14x and 14y used in the lens driving device 1 that drives the moving body 3 including the lens 121 in the optical axis direction by the magnetic driving mechanism 5a. In the lens driving device 1 that corrects camera shake of the moving body including the lens 121 by a magnetic driving mechanism, the present invention may be applied to a spring member that supports the moving body.

DESCRIPTION OF SYMBOLS 1 Lens drive device 2 Support body 3 Moving body 5 Lens drive mechanism 5a Magnetic drive mechanism 11 Spacer 13 Sleeve 14x, 14y Spring member 14s, 14t Plate spring 17 Magnet 18 Yoke 19 Holder 30 Drive coil 140s, 140t Arm part 148s, 148t Moving body side fixing portion 149s, 149t Supporting body side fixing portion

Claims (6)

A movable body including a lens, a support that supports the movable body, one or more spring members that are connected to the support and the movable body, and a magnetic drive mechanism that magnetically drives the movable body. A lens driving device having:
At least one of the one or more spring members includes a support side fixing portion fixed to the support side, a moving body side fixing portion fixed to the moving body side, and the support side fixing portion and the moving body side fixing portion. be stacked a plurality of plate-shaped spring having an arm portion connecting,
In the plate springs adjacent to each other in the optical axis direction in the plurality of plate springs, the shape of the arm portion is different, and the longitudinal spring constant of the plate spring located on the subject side is opposite to the subject side. A lens driving device characterized in that the lens driving device is smaller than a longitudinal spring constant of a plate-like spring located at the center .   2. The lens driving device according to claim 1, wherein the arm portions of the plurality of plate springs adjacent to each other in the lens optical axis direction are not joined at any position. 3. The lens driving device according to claim 1 , wherein an angle direction in which the movable body is easily displaced in a direction orthogonal to a lens optical axis direction is shifted between the plurality of plate springs. The plurality of plate springs are arranged such that angular directions in which the movable body is easily displaced in a direction perpendicular to the lens optical axis direction are alternately and equiangularly spaced around the lens optical axis. The lens driving device according to claim 3 , wherein: 5. The plate springs adjacent to each other in the lens optical axis direction of the plurality of plate springs are such that at least a part of the arm portion is in contact with the lens optical axis direction . The lens driving device according to one item. 6. The lens driving device according to claim 1 , wherein the number of the plate springs is two in the spring member .

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