JP5143643B2 - Lens drive device - Google Patents

Description

  The present invention relates to a lens driving device in which a lens driving mechanism and a spring member are disposed between a moving body having a lens and a support.

A camera mounted on a mobile phone with a camera, a digital camera, or the like includes a lens driving device including a support, a moving body including a lens, and a lens driving mechanism that magnetically drives the moving body in the lens optical axis direction. Have. Further, in such a lens driving device, a spring member is disposed between the support and the moving body, and the spring member has a function of assisting the driving of the moving body. Here, as the spring member, a first spring member disposed on the imaging element side in the lens optical axis direction and a second spring member disposed on the subject side with respect to the first spring member are used. The first spring member and the second spring member have the same basic configuration, and the same spring member is used for the longitudinal spring constant in the lens optical axis direction and the lateral spring constant in the direction orthogonal to the lens optical axis direction. (See Patent Document 1).
JP 2006-201525 A

  The first spring member and the second spring member used in such a lens driving device are required to have a constant spring constant over a wide deformation range in the lens optical axis direction as a longitudinal spring constant, and a lateral spring constant. However, it is difficult to satisfy both of these requirements with one type of spring member. For example, as shown in FIG. 3A, the arm portion 241 extends in an arc shape between a support body side connection portion 249 connected to the support body and a mobile body side connection portion 248 connected to the mobile body. Since the first type spring member 240 has a large transverse spring constant, there is an advantage that the moving body can be supported so as not to move in a direction orthogonal to the lens optical axis. It is difficult to extend the arm portion 241 any more in order to make the longitudinal spring constant constant over the range. On the other hand, as shown in FIG. 5 (a), there are a plurality of arm portions 341 between a support body side connection portion 349 connected to the support body and a mobile body side connection portion 348 connected to the mobile body. The meandering second type spring member 340 has a longitudinal spring over a wide deformation range in the lens optical axis direction even if the arm portion 341 is disposed within a narrow range in the circumferential direction because the arm portion 341 is meandering. Although the constant is constant, since the lateral spring constant is small, it is difficult to support the moving body so as not to shake in the direction orthogonal to the lens optical axis.

  In view of the above problems, an object of the present invention is to provide a lens driving device capable of suitably magnetically driving a moving body in the lens optical axis direction by making the best use of two spring members. It is to provide.

In order to solve the above problems, in the present invention, a support body, a moving body provided with a lens, a lens driving mechanism that magnetically drives the moving body in the lens optical axis direction, the support body, and the movement And a spring member connected between the body and the first spring member disposed on the image sensor side in the lens optical axis direction as the spring member, and the first spring member. A second spring member disposed on the subject side, wherein the first spring member and the second spring member have at least different lateral spring constants in a direction orthogonal to the lens optical axis direction, and the moving body The center of gravity is located at a position biased to one side in the lens optical axis direction with respect to the center position in the lens optical axis direction of the movable body, and of the first spring member and the second spring member, in the lens optical axis direction At the center of gravity A lateral spring constant of one of the near spring members is larger than a lateral spring constant of the other spring member far from the center of gravity in the lens optical axis direction, and the other spring member is more than the lens optical axis than the one spring member. The range in which the longitudinal spring constant in the direction is constant in the optical axis direction of the lens is wide .

  That is, the present invention focuses on the use of two spring members and is characterized by meeting the demands required of the spring members by configuring the two spring members differently. For this reason, the requirements that cannot be satisfied by one type of spring member, for example, 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 are satisfied. Can do. Therefore, by realizing a sufficient level of lateral spring constant, it is possible to prevent blurring in the direction orthogonal to the optical axis (lateral blurring) and to make the vertical spring constant constant over a wide displacement range in the lens optical axis direction. can do. Therefore, according to the present invention, even when the moving body is magnetically driven by the lens driving mechanism, the position of the moving body in the lens optical axis direction is highly accurate without causing blurring in the direction orthogonal to the optical axis. Can be controlled.

Further, the lateral spring constant of the spring member closer to the center of gravity of the first spring member and the second spring member is larger than the lateral spring constant of the spring member farther from the center of gravity. For this reason, since the side where the center of gravity is located in the moving body is supported by the spring member having a large lateral spring constant, it is possible to reliably prevent the lateral displacement of the lens.

In the present invention, the moving body may be configured to have a center of gravity on the side where the imaging element is located with respect to a center position in the lens optical axis direction of the moving body. In this case, a lateral spring constant of the first spring member Is larger than the lateral spring constant of the second spring member, and the second spring member preferably has a wider range in which the longitudinal spring constant is constant in the lens optical axis direction than the first spring member . If comprised in this way, since the image pick-up element side in which a gravity center is located among a moving body is supported by the 1st spring member with a large transverse spring constant, the position shift of the moving body in the horizontal direction can be prevented reliably. .

  In the present invention, each of the first spring member and the second spring member includes a support body side connection portion connected to the support body, a mobile body side connection portion connected to the mobile body, and the support body side connection portion. An arm portion extending between the movable body side connecting portion, and the first spring member and the second spring member are formed with the formation pattern of the arm (length, shape, extending direction, etc. of the arm portion). ) Can be adopted.

  In the present invention, among the first spring member and the second spring member, in the spring member having the larger lateral spring constant, the arm portion extends in the circumferential direction with an arc shape, and the spring having the smaller lateral spring constant. The member can employ a configuration in which the arm portion extends in the circumferential direction while meandering at a plurality of locations.

  In the present invention, of the first spring member and the second spring member, the spring member having the smaller lateral spring constant has a predetermined angular range at least at one location radially outward from the movable body side connecting portion. It is preferable that the support-side connecting portion and the arm have no gap. If comprised in this way, the processus | protrusion for winding the edge part of the coil used for the lens drive mechanism, the protrusion for preventing the inclination of a moving body, etc. can be arrange | positioned using a space | gap.

  The present invention pays attention to the use of two spring members and is characterized in that the two spring members are configured differently to meet the demands required for the spring members. For this reason, the requirements that cannot be satisfied by one type of spring member, for example, 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 are satisfied. Can do. Therefore, by realizing a sufficient level of lateral spring constant, it is possible to prevent blurring in the direction perpendicular to the optical axis (lateral blurring) and to maintain a constant vertical spring constant over a wide displacement range in the lens optical axis direction. Can be. Therefore, according to the present invention, even when the moving body is magnetically driven by the lens driving mechanism, the position of the moving body in the lens optical axis direction is highly accurate without causing blurring in the direction orthogonal to the optical axis. Can be controlled.

  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.

[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. 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.

  1A, 1B, and 2, the lens driving device 1 according to the present embodiment is a thin camera used for a camera-equipped mobile phone or the like. It has a substantially rectangular parallelepiped shape for moving in both directions, the A direction (front side) approaching the object side and the B direction (rear side) approaching the opposite side (image side) from the subject. The lens driving device 1 generally has a moving body 3 having a cylindrical lens holder 12 having one or more lenses 121 and a fixed diaphragm inside, and moves the moving body 3 along the optical axis direction. It has a lens driving mechanism 5 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.

  Here, the moving body 3 includes a lens 121 at one position in the optical axis direction relative to the center position of the moving body 3 in the optical axis X direction. For this reason, the moving body 3 has a center of gravity located at a position that is biased toward the subject side in the lens optical axis direction rather than the center position of the moving body 3 in the optical axis X direction.

  The support 2 includes a rectangular holder 19 for holding an image pickup device (not shown) on the image side, a box-shaped yoke 18 and a spacer 11 located on the subject side, and the yoke 18 and the spacer 11. Are formed with circular incident windows 110 and 180 for taking light from the subject into the lens 121. 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 lens driving mechanism.

  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 first spring member 14x and a second spring connected to the support 2 and the movable body 3 between the holder 19 and the sleeve 13 and between the spacer 11 and the sleeve 13, respectively. A member 14y is provided. Each of the first spring member 14x and the second spring member 14y is made of metal such as beryllium copper or SUS steel, and is formed by pressing a thin plate having a predetermined thickness or etching using a photolithography technique. is there.

  Although detailed configurations of the first spring member 14x and the second spring member 14y will be described later, the first spring member 14x is connected to the holder 19 and the sleeve 13, and the movable body 3 can be moved along the lens optical axis. It is set as the state supported by the support body 2. The second 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 first spring member 14x and the second spring member 14y, the first spring member 14x disposed on the holder 19 side is divided into two spring pieces 14a and 14b, and two terminals of the drive coil 30 are provided. The winding start end and the winding end end are connected to the spring pieces 14a and 14b, respectively. At that time, of the two terminals of the drive coil 30, the object-side terminal passes under a groove (not shown) formed on the outer peripheral surface of the sleeve 13, and then dive under the drive coil 30 and spring pieces. It is routed to 14a. In the first spring member 14x, the spring pieces 14a and 14b are each formed with a terminal 14c, and the first spring member 14x (spring pieces 14a and 14b) also functions as a power supply member for the drive coil 30.

  In this embodiment, the lens driving mechanism 5 further includes a ring-shaped magnetic piece 130 held at the upper end of the sleeve 13, and the magnetic piece 130 is attracted by the attractive force acting between the magnet 17. An urging force in the optical axis direction is applied to the moving body 3. 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 spacer 11 is attached to the inner surface of the top plate portion 185 of the yoke 18 and has a plate portion 115 in which an incident window 110 is formed at the center. Small protrusions 112 are formed at the four corners of the plate portion 115 so as to protrude to the opposite side to the subject side.

  In addition, the holder 19 has small protrusions 192 extending toward the subject at the four corners. The small protrusion 192 of the holder 19 and the small protrusion 112 of the spacer 11 are used when the first spring member 14x and the second spring member 14y are connected to the support 2 respectively.

  Protrusions 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 located on both sides of the lens 121 (lens holder 12) with respect to the optical axis X. It protrudes in the orthogonal direction. When the sleeve 13 (moving body 3) configured as described above is arranged in the support body 2, the projections 13a and 13b are arranged inside the convex portion 182b 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 second spring member 14y are formed in the circumferential direction on the upper end surface (end surface on the subject side) of the sleeve 13, and the lower end surface (end surface on the image sensor side) of the sleeve 13 is formed. ), A plurality of small protrusions 13x for connecting the first spring members 14x are formed in the circumferential direction.

(Basic operation)
In the lens driving device 1 of the present embodiment, the moving body 3 is normally located on the imaging element side (image side). When a current in a predetermined direction is passed through the driving coil 30 in such a state, the driving coil 30 is moved. Each receive 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 second spring member 14y and the front end of the sleeve 13 and between the first 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) is brought to 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 first spring member 14x and the second spring member 14y. Can be stopped. In this embodiment, since the first spring member 14x and the second spring member 14y are plate springs (gimbal springs) in which a linear relationship is established between the elastic force (stress) and the displacement amount (distortion amount), Linearity between the amount of movement of the sleeve 13 and the current passed through the drive coil 30 can be improved. In addition, since two spring members including the first spring member 14x and the second spring member 14y are used, a large balance force is applied in the direction of the optical axis X when the sleeve 13 is stopped. Even if other force such as centrifugal force or impact force acts in the direction of the axis X, the sleeve 13 can be stopped more stably. Further, 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. Therefore, it is possible to prevent the occurrence of a collision sound.

  When such a driving method is adopted, the first spring member 14x and the second spring member 14y have a constant spring constant as a longitudinal spring constant in a wide deformation range in the lens optical axis direction, that is, the sleeve 13. Is required to have a constant spring force generated by the first spring member 14x and the second spring member 14y when moving in the direction of the optical axis X, and the lateral spring constant is large, that is, the moving body 3 is light Although it is calculated | required that it does not shift | deviate to the direction orthogonal to the axis | shaft X, it is difficult to satisfy | fill both these requests | requirements with one kind of spring member. Therefore, in this embodiment, the configuration described below is adopted.

(Detailed configuration of spring member)
With reference to FIG. 1, FIG. 3 (a), and (b), the structure of the spring member (1st spring member 14x and 2nd spring member 14y) used for the lens drive device which concerns on Embodiment 1 of this invention. explain. 3A and 3B are a plan view of the second spring member 14y disposed on the subject side and a side opposite to the subject side (imaging) in the lens driving device 1 according to Embodiment 1 of the present invention. It is a top view of the 1st spring member 14x arrange | positioned at the element side.

  In the present embodiment, as shown in FIGS. 1B and 3A, a first type spring member 240 in which the arm portion 241 extends in an arc shape in the circumferential direction is used as the second spring member 14y. As shown in FIGS. 1B and 3B, as the first spring member 14x, a second type spring member 340 is used in which the arm portion 341 extends in the circumferential direction while meandering at a plurality of locations. ing. Of the two types of spring members 240 and 340, the first type spring member 240 shown in FIG. 3A has a large lateral spring constant so that it does not shake in the direction orthogonal to the optical axis X. Although there is an advantage that the movable body 3 can be supported, it has a property that it is difficult to extend the arm part 140 further in order to make the longitudinal spring constant constant over a wide deformation range in the optical axis X direction. . On the other hand, the second type spring member 340 shown in FIG. 3B has a lens optical axis even if the arm portion 341 is disposed within a narrow range in the circumferential direction because the arm portion 341 meanders. The longitudinal spring constant is constant over a wide range of deformation in the direction, but the transverse spring constant is small. Hereinafter, the configuration of the first type spring member (second spring member 14y) and the second type spring member (first spring member 14x) will be described in detail.

(Configuration of first type spring member 240 and second spring member 14y)
As shown in FIG. 2 and FIG. 3A, the first type spring member 240 (second spring member 14y) is a rectangular frame-shaped support side connecting portion 249 fixed to the support 2 (spacer 11). And an annular moving body side connecting portion 248 fixed to the moving body 3 (sleeve 13), and four plate spring-like arm portions 241 for connecting the supporting body side connecting portion 249 and the moving body side connecting portion 248. ing. A small hole 249 a into which the small protrusion 112 of the spacer 11 is fitted is formed in each of the four corner portions of the support body side connection portion 249. The small protrusion 112 is fitted into the small hole 249 a to connect the support body side connection portion 249 and the spacer 11. After the positioning, the support side connecting portion 249 and the spacer 11 are fixed by a method such as applying and curing an adhesive in the small hole 249a. Further, in the moving body side connecting portion 248, rectangular concave portions 248 b that are recessed radially inward are formed at portions facing the four corner portions of the supporting body side connecting portion 249, and the rectangular concave portions 248 b are disposed on both sides in the circumferential direction. A small hole 248a is formed so as to be sandwiched between the two. Therefore, after the small protrusion 13y is fitted into the rectangular recess 248b, the movable body side connecting portion 248 and the sleeve 13 are positioned, and then the moving body side connecting portion 248 and the sleeve 13 are applied by a method such as applying and curing an adhesive in the small hole 248a. And fixing.

  The first type spring member 240 (second spring member 14y) is formed by pressing a metal thin plate or etching using a photolithography technique. At this time, the moving body side connecting portion 248 and Four notches 243 extending in the circumferential direction are formed between the support-side connecting portions 249 and the four arm portions 241 extending in the circumferential direction are formed by the notches 243.

  That is, each of the four notches 243 extends in the circumferential direction, but extends so as to shift from the inner peripheral side to the outer peripheral side at a midway position in the clockwise CW direction, and adjacent notches in the circumferential direction. The portions corresponding to about ½ of the length direction of 243 overlap in the radial direction. For this reason, a narrow arm portion 241 whose inner peripheral edge portion is defined by a portion located on the counterclockwise CCW side in the notch 243 is formed in a portion where the notches 243 adjacent in the circumferential direction overlap each other. The outer peripheral edge portion of the arm portion 241 is defined by a portion located on the clockwise CW side in the notch 243 adjacent to the notch 243 in the counterclockwise CCW direction.

(Configuration of Second Type Spring Member 340 and First Spring Member 14x)
As shown in FIGS. 2 and 3 (b), the second type spring member 340 (first spring member 14x) is composed of four annular small support-side connecting portions held by the support 2 (holder 19). 349, an annular frame-shaped movable body side coupling portion 348 coupled to the upper end of the sleeve 15, and four arm portions 341 that couple the support body side coupling portion 349 and the movable body side coupling portion 348. All of the four arm portions 341 extend in the clockwise CW direction while meandering at a plurality of locations from the connecting portion with the moving body side connecting portion 348, and then turn back in the counterclockwise CCW direction to return to the moving body side connecting portion. 349. A plurality of small holes 348 a are formed in the moving body side connecting portion 348, and small protrusions 13 y formed at the lower end portion of the sleeve 13 are fitted into these small holes 348 a, so that the moving body side connecting portion 348 and the sleeve 13 are connected. The lower end is connected.

  Here, the first spring member 14 x is divided into two spring pieces 14 a and 14 b by a slit-shaped moving body side connecting portion 348 having an annular frame shape. However, the first spring member 14x is connected by a connecting portion 14e indicated by a one-dot chain line until the middle of manufacture, and is cut at the constricted portion 14f during the assembly to the lens driving device 1, thereby providing a spring having a terminal 14c. It is divided into pieces 14a and 14b.

  In the second type spring member 340 (first spring member 14x) configured as described above, even if the length of the arm 340 is sufficiently secured because the arm portion 341 meanders, the circumferential range is narrow. Is only occupied by the arm portion 341. Therefore, in the second type spring member 340 (first spring member 14x), the support body side connection portion 349 and the support body side connection portion 349 over the predetermined angle range are provided at two opposite positions on the outside of the annular frame-shaped moving body side connection portion 348. A gap 14g where the arm 340 does not exist is formed, and a protrusion 14h that protrudes outward from the moving body side coupling portion 348 is formed in the gap 14g. The projection 14h includes a constricted portion 14i at the base portion, and in this embodiment, the projection 14h is used to hold and hold the coil terminal. In this embodiment, the inner peripheral edge of the movable body side connecting portion 348 is formed with a concave portion 14j that is recessed outward in the radial direction at a portion where the protrusion 14h is formed.

(Main effects of this form)
As described above, in this embodiment, paying attention to the use of two spring members (the first spring member 14x and the second spring member 14y), the two spring members are configured differently, so that the spring It is characterized by responding to demands required for members. In other words, in the present embodiment, a first type spring member 240 in which the arm portion 241 extends in an arc shape in the circumferential direction is used as the second spring member 14y, and the first type spring member 240 has an optical axis X. Although it is difficult to extend the arm portion 140 beyond this in order to make the longitudinal spring constant constant over a wide deformation range in the direction, there is an advantage that the lateral spring constant is large. On the other hand, as the first spring member 14x, a second type spring member 340 is used in which the arm portion 341 extends in the circumferential direction while meandering at a plurality of locations. Although the spring constant is small, the longitudinal spring constant is constant over a wide deformation range in the lens optical axis direction even when the arm portion 341 is disposed within a narrow range in the circumferential direction because the arm portion 341 meanders. There is. In the present embodiment, different types of spring members (first type spring member 240 and second type spring member 340) are used in combination as the first spring member 14x and the second spring member 14y. 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. Therefore, by realizing a sufficient level of lateral spring constant, it is possible to prevent the moving body 3 from shifting in the lateral direction and to make the longitudinal spring constant constant over a wide displacement range in the optical axis X direction. Therefore, when the moving body 3 is driven by the magnetic drive by the lens driving mechanism 5, it is possible to prevent blurring in the direction orthogonal to the optical axis X and the position of the moving body 3 in the optical axis X direction with high accuracy. Can be controlled.

  In this embodiment, since the moving body 3 includes the lens 121 at a position biased toward the subject, the moving body 3 is positioned closer to the subject than the center position of the moving body 3 in the optical axis X direction. The first type spring member 240 having a large lateral spring constant is disposed as the second spring member 14y on the subject side. For this reason, it is possible to reliably prevent the lateral displacement and inclination of the lens 121. Further, it is possible to reliably prevent the displacement and inclination of the moving body 3 in the lateral direction.

[ Reference example ]
4A and 4B are an external view and an exploded perspective view, respectively, of the lens driving device according to the reference example of the present invention viewed obliquely from above. FIGS. 5A and 5B are a plan view of the second spring member 14y disposed on the subject side in the lens driving device 1 according to the reference example of the present invention, and a side opposite to the subject side (on the image sensor side). 2) is a plan view of the first spring member 14x disposed in (1). 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.

  In the present embodiment, contrary to the first embodiment, as shown in FIG. 4, as the second spring member 14y located on the subject child side, the arm portion 341 extends in the circumferential direction while meandering at a plurality of locations. Two types of spring members 340 are used, and the first type spring member 240 in which the arm portion 241 extends in an arc shape in the circumferential direction is used as the first spring member 14x located on the imaging element side.

  Of the two types of spring members 240 and 340, the first type spring member 240 shown in FIG. 5B has a large transverse spring constant, and therefore can support the moving body 3 so that the optical axis X does not shift. However, it is difficult to extend the arm portion 140 further in order to make the longitudinal spring constant constant over a wide deformation range in the optical axis X direction. On the other hand, the second type spring member 340 shown in FIG. 5A has a lens optical axis even if the arm portion 341 is disposed within a narrow range in the circumferential direction because the arm portion 341 meanders. Although the longitudinal spring constant is constant over a wide range of deformation in the direction, the transverse spring constant is small.

  As shown in FIG. 5 (a), the second type spring member 340 (second spring member 14y) includes four annular small support body side coupling portions 349 held by the support body 2 (holder 19), An annular frame-shaped movable body side coupling portion 348 coupled to the upper end of the sleeve 15, and four arm portions 341 that couple the support body side coupling portion 349 and the movable body side coupling portion 348 are provided. These four arm portions 341 extend in the clockwise CW direction while meandering at a plurality of locations from the connecting portion with the moving body side connecting portion 348, and then turn back in the counterclockwise CCW direction to return to the moving body side connection. It extends to part 349. The moving body side connecting portion 348 is formed with a plurality of small holes 348 a and rectangular recesses 348 b and is connected to the upper end portion of the sleeve 13.

  The first type spring member 240 (first spring member 14x) includes four support body side connecting portions 249 having small holes 249a, and an annular moving body side connecting portion 248 fixed to the moving body 3 (sleeve 13). , And four leaf spring-like arm portions 241 extending in a circular arc shape in the circumferential direction between the support body side connecting portion 249 and the moving body side connecting portion 248. A plurality of small holes 248 a are formed in the moving body side connecting portion 248 for connection with the lower end portion of the sleeve 13.

  Here, the first spring member 14 x is divided into two spring pieces 14 a and 14 b by a slit-shaped moving body side connecting portion 248 having an annular frame shape. However, the first spring member 14x is connected by a connecting portion (not shown) until the middle of manufacture, and is cut at the constricted portion during the assembly to the lens driving device 1, whereby the spring piece 14a provided with the terminal 14c. , 14b. The arm portion 241 is also formed by a notch 243 extending in the circumferential direction. Since other configurations are the same as those of the first embodiment, description thereof is omitted.

  Thus, in this embodiment, paying attention to the use of two spring members (the first spring member 14x and the second spring member 14y), the two spring members are configured differently to obtain the spring member. It is characterized by responding to the demands. In other words, in the present embodiment, a first type spring member 240 in which the arm portion 241 extends in an arc shape in the circumferential direction is used as the first spring member 14x, and the first type spring member 240 has an optical axis X. Although it is difficult to extend the arm portion 140 beyond this in order to make the longitudinal spring constant constant over a wide deformation range in the direction, there is an advantage that the lateral spring constant is large. On the other hand, as the second spring member 14y, a second type spring member 340 is used in which the arm portion 341 extends in the circumferential direction while meandering at a plurality of locations. Although the spring constant is small, the longitudinal spring constant is constant over a wide deformation range in the lens optical axis direction even when the arm portion 341 is disposed within a narrow range in the circumferential direction because the arm portion 341 meanders. have. Therefore, according to the present embodiment, there is a demand for a large lateral spring constant that cannot be satisfied by one type of spring member, and a demand for a constant longitudinal spring constant over a wide range in the lens optical axis direction. Can be satisfied. Therefore, by realizing a sufficient level of lateral spring constant, it is possible to prevent the moving body 3 from shifting in the lateral direction and to make the longitudinal spring constant constant over a wide displacement range in the optical axis X direction. Therefore, when the moving body 3 is driven by the magnetic drive by the lens driving mechanism 5, it is possible to prevent blurring in the direction orthogonal to the optical axis X and the position of the moving body 3 in the optical axis X direction with high accuracy. Can be controlled.

  In this embodiment, the first type spring member 240 having a large lateral spring constant is used as the first spring member 14x on which the image sensor is arranged. For this reason, even when an external force in a direction orthogonal to the optical axis direction is applied to the moving body 3, it is possible to prevent deterioration in image quality. That is, in the small lens driving device 1, blurring in the direction orthogonal to the optical axis X on the imaging element side of the moving body 3 and blurring in the direction orthogonal to the optical axis X on the subject side of the moving body 3 In the present embodiment, the blur on the image sensor side has a larger influence on the image quality. However, in this embodiment, the lateral spring constant of the first spring member 14x arranged on the larger influence side is increased. The influence of can be suppressed small.

  Further, in the second type spring member 340 (second spring member 14y), the arm portion 341 meanders, and even if the length of the arm 340 is sufficiently secured, the narrow range in the circumferential direction is maintained. 341 only occupies. Accordingly, in the second type spring member 340 (second spring member 14y), the support body side connection portion 349 and the support body side connection portion 349 and the two opposite positions outside the annular frame-shaped moving body side connection portion 348 over a predetermined angle range. Since the gap 14g where the arm 340 does not exist is formed, various structures can be provided to the sleeve 13 by using the gap 14g. For example, as shown by a one-dot chain line f in FIG. 5A, the protrusion 13f is provided at a position corresponding to the gap 14g in the sleeve 13, while the support 2 side (for example, the spacer 11 shown in FIG. 1B). If a stopper (not shown) with which the protrusion 13f abuts when the moving body 3 is inclined is provided on the side, a structure that prevents the inclination of the moving body 3 using the gap 14g can be employed.

[ Embodiment 2 ]
In the above reference example , the lateral spring constant of the first spring member 14x disposed on the image sensor side is increased regardless of whether the center of gravity of the moving body 3 is shifted in the direction of the image sensor side or the subject side. In this embodiment, the movable body 3 has a center of gravity located at a position that is biased toward the image sensor side with respect to the center position of the movable body 3 in the optical axis X direction. A first type spring member 240 having a large constant is used, and a second type spring member 340 is used for the second spring member 14y on the subject side.

  For this reason, in the present embodiment, of the image pickup device side and the subject side of the moving body 3, the image blur due to lateral blurring has a great influence on the image quality, and the image pickup device side close to the center of gravity is the first type having a large lateral spring constant. Since it is supported by the spring member 240 (first spring member 14x), it is possible to effectively prevent the image quality from being deteriorated due to the lateral blurring of the moving body 3.

  Note that when the center of gravity is disposed at a position biased toward the image sensor in the moving body 3, the configuration in which the lens 121 is disposed at a position biased toward the image sensor and the position of the lens 121 are the same as in the first embodiment. Instead of arranging at a position biased toward the subject, a configuration in which the structure of the sleeve 13 is changed may be employed.

(Other embodiments)
In the first type spring member 240 used in the above-described embodiment, the arm portion 241 is formed in a single layer. However, after the arm portion 241 extends in an arc shape in the circumferential direction, the arm portion 241 is folded back and again in the circumferential direction. The structure extended in circular arc shape may be sufficient. Further, in the second type spring member 340 used in the above embodiment, the four arm portions 341 are formed so as to be substantially rotationally symmetric so as to extend in the same direction. You may employ | adopt the structure etc. in which two are formed in line symmetry.

(A), (b) is the external view which looked at the lens drive device based on Embodiment 1 of this invention from diagonally upward, and an exploded perspective view, respectively. It is explanatory drawing which shows typically operation | movement of the lens drive device shown in FIG. (A), (b) is the top view of the 2nd spring member arrange | positioned at the to-be-photographed object side in the lens drive device which concerns on Embodiment 1 of this invention, respectively, and the object side (image sensor side) opposite side It is a top view of the arrange | positioned 1st spring member. (A), (b) is the external view which looked at the lens drive device which concerns on the reference example of this invention from diagonally upward, and an exploded perspective view, respectively. (A), (b) is the top view of the 2nd spring member arrange | positioned at the to-be-photographed object side in the lens drive device which concerns on the reference example of this invention, respectively, and it has arrange | positioned to the object side (image sensor side). It is a top view of the 1st spring member.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Lens drive device 2 Support body 3 Moving body 11 Spacer 13 Sleeve 14x 1st spring member 14y 2nd spring member 17 Magnet 18 Yoke 19 Holder 30 Drive coil 240 1st type spring member 340 2nd type spring members 241 and 341 Arm part 248, 348 Moving body side connection part 249, 349 Support body side connection part

Claims (5)

A lens having a support, a movable body including a lens, a lens driving mechanism that magnetically drives the movable body in the lens optical axis direction, and a spring member connected between the support and the movable body In the drive device,
As the spring member, a first spring member disposed on the imaging element side in the lens optical axis direction, and a second spring member disposed on the subject side with respect to the first spring member,
The first spring member and the second spring member have at least different lateral spring constants in a direction perpendicular to the lens optical axis direction,
The moving body has a center of gravity located at a position biased to one side in the lens optical axis direction from the center position in the lens optical axis direction of the moving body,
Of the first spring member and the second spring member, the lateral spring constant of one spring member close to the center of gravity in the lens optical axis direction is the lateral spring constant of the other spring member far from the center of gravity in the lens optical axis direction. Greater than the spring constant,
2. The lens driving device according to claim 1, wherein the other spring member has a wider range in which the longitudinal spring constant in the lens optical axis direction is constant in the lens optical axis direction than the one spring member . The movable body includes the center of gravity on the side where the imaging element is located with respect to the center position in the lens optical axis direction of the movable body,
The lateral spring constant of the first spring member is larger than the lateral spring constant of the second spring member,
2. The lens driving device according to claim 1, wherein the second spring member has a wider range in which a longitudinal spring constant is constant in the lens optical axis direction than the first spring member . Each of the first spring member and the second spring member includes a support-side connecting portion connected to the support, a moving-body-side connecting portion connected to the moving body, the support-side connecting portion, and the moving-body side connection. An arm part extending between the parts,
The lens driving device according to claim 1, wherein the first spring member and the second spring member have different formation patterns of the arms . Of the first spring member and the second spring member, in the spring member having a larger lateral spring constant, the arm portion extends in the circumferential direction in an arc shape, and in the spring member having a smaller lateral spring constant, The lens driving device according to claim 3 , wherein the arm portion extends in the circumferential direction while meandering at a plurality of locations . Of the first spring member and the second spring member, in the spring member having the smaller lateral spring constant, the support side connecting portion is provided at least at one place radially outside the moving body side connecting portion over a predetermined angle range. The lens driving device according to claim 3, further comprising a gap in which the arm does not exist .

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