JPWO2011105470A1 - Lens driving device and camera module - Google Patents

Abstract

An object of the present invention is to displace the holder smoothly in the optical axis direction of a lens while applying a current while holding the holder at a position when the application of current is stopped by imbalance the magnetic force between a magnet and a magnetic plate. Provided are a lens driving device and a camera module. A magnetic plate 31 is arranged so that the center of the magnetic plate 31 approaches the groove 63 from the center of the magnet 70 in plan view. In this case, the magnetic force generated between the magnetic plate 31 and the magnet 70 is biased toward the kerf 63 side. Thereby, the cut groove 63 is pressed against the shaft 90 more strongly than the hole 62. For this reason, the movement of the holder 60 when a current is applied to the coil 20 becomes smooth. When the application of current to the coil 20 is stopped, the holder 70 is pressed against the shaft 90 by the magnetic force generated between the magnetic plate 31 and the magnet 70, and the holder 60 is held in that position. [Selection] Figure 1

Description

  The present invention relates to a lens driving device and a camera module including the same.

  Conventionally, a camera module is mounted on a mobile phone or the like. Such a camera module includes a lens driving device for focus adjustment. The lens driving device displaces the lens in the optical axis direction according to the control signal. Thereby, the focus adjustment with respect to the subject is performed.

  As one of the lens driving devices, a moving magnet type lens driving device is known (for example, Patent Document 1). In this type of lens driving device, a magnet is attached to a holder that holds a lens. The holder is supported so as to be displaceable in the optical axis direction of the lens with respect to the base. A coil is arranged on the base so as to face the magnet on the holder side. The holder is driven along with the magnet in the optical axis direction of the lens by an electromagnetic driving force generated by applying a current to the coil.

  In this configuration, the magnetic plate can be disposed so as to face the magnet with the coil interposed therebetween. In this case, a magnetic force is generated between the magnet and the magnetic plate. By making this magnetic force unbalanced with respect to the optical axis of the lens, a force in a direction perpendicular to the optical axis of the lens can be applied to the holder. For example, the holder is pressed against the support portion by this force. Thereby, even if the application of the current to the coil is stopped, the holder can be positioned at the position when the current application is stopped.

JP 2008-185749 A

  In the lens driving device, the holder is supported by a pair of shafts attached to the base so as to be displaceable in the optical axis direction of the lens. In this case, the holder is provided with an engaging portion that engages with each shaft. Each of the engaging portions can be a hole having substantially the same diameter as the shaft.

  However, if this is done, there is a risk that the engagement between the hole and the shaft will be strengthened due to misalignment of the shaft, hole formation error, etc., and the holder will not be smoothly displaced along the shaft. In order to avoid this, one of the two engaging portions is a hole having a diameter substantially the same as that of the shaft, and the other is a hole or cut having an ellipse or a straight portion so as to allow the above-described displacement and formation error. A grooved configuration can be taken.

  However, in this case, the contact area with the shaft is large in the hole having the same diameter as the shaft of the two engaging portions, whereas the contact with the shaft is in the hole or the groove having the ellipse or the straight portion. The area becomes smaller. In this state, if the magnetic force between the magnet and the magnetic plate is imbalanced as described above and a force is applied to the holder, the difference between the contact areas causes the shaft and the corresponding hole or kerf to be separated. The friction force is different. As a result, the holder may not be smoothly displaced along the shaft when a current is applied.

  The present invention has been made to solve such a problem, and by applying an imbalance in the magnetic force between the magnet and the magnetic plate, the current is applied while holding the holder at the position when the current application is stopped. In some cases, an object of the present invention is to provide a lens driving device that can smoothly displace the holder in the optical axis direction of the lens and a camera module using the lens driving device.

  A first aspect of the present invention relates to a lens driving device. The lens driving device according to this aspect includes a base, two shafts having a circular cross section attached to the base, a holder that holds the lens and is supported by the shaft so as to be displaceable in the optical axis direction of the lens. And a magnet mounted on the holder, a coil mounted on the base so as to face the magnet, and a magnetic plate disposed on the base side so as to face the magnet across the coil. The holder is provided with a first engaging portion and a second engaging portion that respectively engage with the two shafts. In the first engagement portion and the second engagement portion, the contact area between the first engagement portion and the shaft is larger than the contact area between the second engagement portion and the shaft. Configured as follows. In addition, the magnetic force generated between the magnetic plate and the magnet is unbalanced in a plane perpendicular to the optical axis of the lens, and the magnetic force is applied to the first engagement portion and the second engagement. It is comprised so that it may apply more largely in the direction of the said 2nd engaging part among joint parts.

  A second aspect of the present invention relates to a camera module. A camera module according to this aspect includes the lens driving device according to the first aspect, an image sensor that receives light collected by the lens, and a control unit that applies a control signal for the coil.

  According to the present invention, since the magnetic force between the magnet and the magnetic plate is unbalanced in a plane orthogonal to the optical axis of the lens, the holder can be held at the position when the current application is stopped. In addition, since the magnetic force is applied more to the second engaging portion having a smaller contact area with the shaft, the first engaging portion and the second engaging portion, so that the holder is applied when a current is applied. Can be smoothly displaced in the optical axis direction of the lens.

  The effects and significance of the present invention will become more apparent from the following description of embodiments. However, the following embodiment is merely an example when the present invention is implemented, and the present invention is not limited to what is described in the following embodiment.

It is a figure which shows the structure of the lens drive device which concerns on embodiment. It is a figure which shows the structure of the base which concerns on embodiment. It is a figure explaining the attachment method of the holder and shaft which concern on embodiment. It is a figure which shows the attachment form of the magnetic board which concerns on embodiment. It is a figure which shows the relationship between the hole and shaft which concern on embodiment. It is a figure which shows the relationship between the groove and shaft which concerns on embodiment. It is a figure explaining operation | movement of the lens drive device which concerns on embodiment. It is a figure which shows the structure of the camera module which concerns on embodiment. It is a figure which shows the verification example which concerns on arrangement | positioning of the magnetic board which concerns on embodiment. It is a figure which shows the structure of the lens drive device which concerns on the example of a change of embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram illustrating a configuration of a lens driving device. FIG. 1A is an exploded perspective view of the lens driving device. FIG. 1B is a perspective view showing the configuration of the lens driving device before the cover 100 is attached, and FIG. 1C is a perspective view of the lens driving device with the cover 100 attached. . In the present embodiment, the lens is not shown for convenience.

  Referring to FIG. 1, the lens driving device includes a base 10, a coil 20, magnetic plates 31 and 32 (the magnetic plate 32 is not shown in FIG. 1), a printed circuit board 40, a filter 50, and a holder 60. A magnet 70, a shaft holder 80, a shaft 90, and a cover 100.

  The base 10 has a square shape with chamfered corners in plan view. A series of coils 20 are attached to the base 10 in two stages. The winding direction of the coils 20 at each stage is opposite to each other. Magnetic plates 31 and 32 are bonded to the outer surface of the coil 20. A printed circuit board 40 is attached to the side surface of the base 10, and two ends of the coil 20 are soldered to the printed circuit board 40. Further, a step (not shown) is formed on the back surface of the base 10, and the filter 50 is attached to the step. The filter 50 is an infrared ray removal filter.

  The holder 60 has an octagonal shape in plan view. A circular opening 61 for accommodating the lens barrel is formed in the holder 60 at the center position. The optical axis of the lens coincides with the center of the octagon defined by the outer shape of the holder 60 in plan view. The eight side surfaces of the holder 10 are arranged so as to be symmetric with respect to the optical axis of the lens mounted in the opening 61. Of these eight side surfaces, magnets 70 are mounted on four side surfaces that are not adjacent to each other.

  The four magnets 70 are, for example, sintered magnets made of neodymium or the like, and have a two-pole arrangement structure in which N and S are magnetized on one side. The size and magnetic strength of each magnet 70 are equal to each other. Further, each magnet 70 is arranged at a position where the center thereof is shifted upward by a certain distance from the center of the corresponding side surface. The two magnets 70 are arranged symmetrically with respect to the optical axis of the lens, and the remaining two magnets 70 are also arranged symmetrically with respect to the optical axis of the lens.

  The holder 60 is formed with holes 62 and kerfs 63 at diagonal positions. A shaft 90 is passed through the hole 62 and the cut groove 63, and the holder 60 is supported so as to be displaceable in the optical axis direction of the lens. The shaft 90 is made of a metal member and has a circular cross section.

  The cover 100 has a square shape with chamfered corners in plan view. The outer shape of the cover 100 in plan view is substantially equal to the outer shape of the base 10. The shape of the inner surface of the cover 100 in plan view is substantially the same as the outer shape of the portion of the base 10 where the coil 20 and the magnetic plates 31 and 32 are mounted. The cover 100 is formed with an opening 101 through which light passes. Further, a flange portion 102 and a hole 102 a are formed on the side surface of the cover 100.

  2A is a perspective view showing the configuration of the base 10, and FIG. 2B is a perspective view when the base 10 is viewed from the back side. As illustrated, the base 10 is made of a frame-shaped member. The base 10 is formed with an opening 11 for allowing light to pass through. Further, coil mounting portions 12 a and 12 b for winding the coil 20 are formed on the side surface of the base 10 over the entire circumference.

  A shaft holding portion 13 is formed on the upper surface of the base 10, and a hole 13 a for press-fitting the shaft 90 is formed in the shaft holding portion 13. A hole 13b for press-fitting the shaft 90 is formed at a position coaxial with the hole 13a.

  Referring to FIG. 2B, a receiving portion 14 to which the shaft holder 80 is attached is formed on the upper surface of the base 10 at a position that is diagonally related to the shaft holding portion 13. The receiving portion 14 is formed with a hole portion 14a that fits with the protrusion 83 (see FIG. 3A) of the shaft holder 80. Further, in the vicinity of the receiving portion 14, a notch 14 b that engages with the flange portion 81 of the shaft holder 80 is formed. Further, a hole 14 c into which the shaft 90 is press-fitted is formed below the receiving portion 14. When the shaft holder 80 is attached to the receiving portion 14, the hole 14c faces the hole 82 (see FIG. 3A) of the shaft holder 80.

  Referring to FIG. 1A, a step portion 15 is formed on the side surface of the base 10, and a locking piece 15 a is formed on the step portion 15. Further, a recess 16 is formed on the other side surface of the base 10, and two protrusions 16 a are formed in the recess 16. As shown in the figure, the printed board 40 has two holes 41 at positions corresponding to the two protrusions 16a. The protrusions 16 a are inserted into the two holes 41 and the printed circuit board 40 is mounted in the recess 16.

  Further, a groove 17 is formed in the base 10 above the step portion 15. The groove 17 functions as an adhesive reservoir groove when the magnetic plate 31 is bonded to the outer surface of the coil 20 as will be described later.

  At the time of assembly, first, the coil 20 is attached to the base 10 shown in FIG. Further, the printed circuit board 40 is mounted, and the end of the coil 20 is soldered to the printed circuit board 40. Thereafter, the holder 60 to which the lens and the magnet 70 are attached is accommodated in the frame of the base 10 from above the base 10.

  FIG. 3A is a diagram illustrating a state in which the holder 60 is accommodated in the base 10. Thereafter, the shaft holder 80 is mounted on the receiving portion 14 so that the protrusion 83 is fitted into the hole 14a on the base side (see FIG. 2B). At this time, the flange portion 81 of the shaft holder 80 is engaged with the notch 14 b on the upper surface of the base 10.

  FIG. 3B is a view showing a state in which the shaft holder 80 is thus attached to the receiving portion 14. In this state, the holes 13a and 13b and the hole 62 of the holder 60 are aligned, and one shaft 90 is press-fitted from the hole 13a. The tip of the shaft 90 is press-fitted into the hole 13a, passes through the hole 62, and is then press-fitted into the hole 13b (see FIG. 2A). In this state, the rear end of the shaft 90 is supported by the hole 13a. Thus, the mounting of one shaft 90 to the base 10 and the engagement between the shaft 90 and the hole 62 are completed.

  Further, in this state, the hole 82 of the shaft holder 80, the hole 14c of the base 10 (see FIG. 2B), and the kerf 63 of the holder 60 (see FIG. 1A) are aligned, and the other The shaft 90 is press-fitted from the hole 82. The tip of the shaft 90 is press-fitted into the hole 82, passes through the kerf 63, and is then press-fitted into the hole 13c. In this state, the rear end of the shaft 90 is supported by the hole 82. Thus, the mounting of the other shaft 90 to the base 10 and the engagement between the shaft 90 and the kerf 63 are completed.

  By mounting the two shafts 90 in this manner, the holder 60 is mounted on the base 10 so that it can be displaced in the optical axis direction of the lens. Thereafter, the two magnetic plates 31 and 32 are bonded to the outer surface of the coil 20.

  FIGS. 4A and 4B are diagrams showing the mounting state of the magnetic plates 31 and 32. 1A is a perspective view when the lens driving device is viewed from substantially the same angle as FIG. 1B, and FIG. 1B is a perspective view of the lens driving device from the state of FIG. It is a perspective view of the state rotated about 90 degrees in the counterclockwise direction about the axis. As shown in FIG. 2B, a magnetic plate 32 is bonded to the outer surface of the coil 20 in addition to the magnetic plate 31. A groove 18 is formed in the vicinity of the magnetic plate 32 of the base 10. At the time of bonding of the magnetic plates 31 and 32, the grooves 17 and 18 function as an adhesive reservoir groove.

  After the magnetic plates 31 and 32 are thus mounted, the cover 100 is mounted on the base from above as shown in FIG. At this time, the flange portion 102 of the cover is fitted into the step portion 15 of the base 10, and the hole 102 a of the flange portion 102 is engaged with the locking piece 15 a of the step portion 15. In this way, the assembly of the lens driving device is completed as shown in FIG.

  FIG. 5 is a diagram illustrating an engagement relationship between the hole 62 formed in the holder 60 and the shaft 90. 4A is a top view of the holder 60, FIG. 2B is a cross-sectional view taken along the line BB ′ of FIG. 1A, and FIG. 4C is a hole 62 in a state where the shaft 90 is inserted. It is a top view of the part.

  As shown in FIG. 5B, the depth of the portion of the hole 62 where the shaft 90 is inserted is Q. The diameter R of the hole 62 is slightly larger than the diameter P of the shaft 90. Therefore, the holder 60 can be displaced in the optical axis direction of the lens while being in sliding contact with the shaft 62.

  FIG. 6 is a view showing an engagement relationship between the kerf 63 formed in the holder 60 and the shaft 90. 2A is a top view of the holder 60, FIG. 2B is a cross-sectional view taken along the line CC ′ of FIG. 1A, and FIG. 2C is a kerf with the shaft 90 inserted therein. It is a top view of the part of 63. FIG.

  As shown in FIG. 5B, the depth of the portion of the kerf 63 into which the shaft 90 is inserted is S. As shown in FIG. 5C, the cut groove 63 is formed with a semicircular arc portion 63 a and two wall surface portions 63 b following the arc portion 63. The two wall surface parts 63b are parallel to each other and parallel to the optical axis of the lens. The shaft 90 is inserted between the two wall surface parts 63b. The distance T between the two wall surface parts 63b is slightly larger than the diameter P of the shaft 90. With this configuration, the holder 60 can be displaced in the optical axis direction of the lens while being in sliding contact with the shaft 62.

  FIG. 7 is a diagram illustrating the driving operation of the lens driving device. This figure is a diagram schematically showing the A-A 'cross section of FIG. In the figure, a black dot mark on the circle and a cross mark on the circle indicate the direction of current flow. A black dot mark on the circle indicates a direction toward the drawing reference person, and a cross mark on the circle indicates a direction away from the drawing reference person.

  As shown in the figure, the N pole region of the magnet 70 is opposed to the upper portion 21 of the coil 20, and the S pole region of the magnet 70 is opposed to the lower portion 22. When a current in the direction shown in FIG. 7A flows through the coil 20, an upward driving force acts on the magnet 70, and the lens holder 60 is displaced in the upward direction in the figure. As a result, the lens holder 60 is displaced upward as shown in FIG. In this state, when the application of current is stopped, the holder 60 is pressed against the shaft 90 by the magnetic force between the magnetic plates 31 and 32 and the magnet 70 and is held at the position when the current application is stopped. 7B, when a reverse current is applied to the coil 20, the lens holder 60 is displaced downward.

  In this manner, the lens is positioned at the on-focus position by moving the lens holder 60 upward and downward. The home position of the lens holder 60 is a position where the lower surface of the lens holder 60 comes into contact with the base 10.

  FIG. 8 is a diagram showing a schematic configuration of a camera module in which the lens driving device having the above configuration is mounted. In the figure, reference numeral 1 denotes a lens driving device.

  An image sensor 200 is disposed below the base 10. The base 10 is provided with a hall element 110 as a position sensor, and the position of the lens holder 60 is detected based on a signal from the hall element 110.

  During the focus operation, a CPU (Central Processing Unit) 301 controls the driver 302 to displace the lens holder 60 from the home position to a predetermined position in the optical axis direction of the lens. At this time, a position detection signal from the Hall element 110 is input to the CPU 301. At the same time, the CPU 301 processes a signal input from the image sensor 200 and acquires a contrast value of the captured image. Then, the position of the lens holder 60 with the best contrast value is acquired as the on-focus position.

  Thereafter, the CPU 301 drives the lens holder 60 toward the acquired on-focus position. At that time, the CPU 301 monitors the signal from the hall element 110 and drives the lens holder 60 until the signal from the hall element 110 reaches a state corresponding to the on-focus position. Thereby, the lens holder 60 is positioned at the on-focus position.

  In the present embodiment, as shown in FIG. 4, two magnetic plates 31 and 32 are arranged. A force in a direction perpendicular to the optical axis of the lens is applied to the holder 60 by the magnetic force between the two magnetic plates 31 and 32 and the magnet 70. With this force, the lens holder 60 is pressed against the shaft 90 as described above. Thereby, even if the application of the current to the coil 20 is stopped, the holder 60 can be positioned at the position at the time of stopping the current application.

  In addition, in the present embodiment, the positions of the magnetic plates 31 and 32 are adjusted to positions deviated from the center position of the side surface of the holder 60 around which the coil 20 is wound toward the shaft holder 80 side. Thereby, the movement of the holder 60 at the time of an electric current application is performed smoothly.

  FIG. 9 is a diagram for explaining the effect when the positions of the magnetic plates 31 and 32 are adjusted as described above. FIGS. 5A to 5C schematically show the resultant magnetic forces F1 and F2 generated between the magnetic plates 31 and 32 and the magnet 70 when the positions of the magnetic plates 31 and 32 are changed. Yes. Further, the centers of the magnets 70 in plan view are indicated by L1 and L2. FIG. 4D schematically shows a contact state between the shaft 90 and the hole 62 and the kerf 63.

  In FIG. 2A, the magnetic plates 31 and 32 are arranged so that the centers of the magnetic plates 31 and 32 coincide with the centers L1 and L2 of the magnet 70 in plan view. In this case, the resultant magnetic force generated between the magnetic plates 31 and 32 and the magnet 70 is F1. With this resultant force F1, the hole 62 and the kerf 63 are pressed against the shaft 90 as shown in FIG. In this case, the hole 62 has an arc portion having substantially the same diameter as the shaft 90 and is in contact with the outer periphery of the shaft 90, and the cut groove 63 is in contact with the outer periphery of the shaft 90 with a flat surface portion (wall surface 63 b). For this reason, the contact area with the shaft 90 is considerably larger in the hole 62. That is, the coefficient of friction with the shaft 90 is greater in the hole 62 than in the kerf 63. Therefore, the frictional force with the shaft 90 due to the resultant force F <b> 1 when the holder 60 is displaced in the optical axis direction of the lens is larger in the hole 62 than in the groove 63. Due to this difference in frictional force, the movement of the holder 60 when a current is applied to the coil 20 is less likely to be performed smoothly.

  In FIG. 4B, the magnetic plate 31 is disposed so that the center of the magnetic plate 31 approaches the kerf 63 from the center L1 of the magnet 70 in plan view. In this case, the resultant force F2 of the magnetic force generated between the magnetic plates 31 and 32 and the magnet 70 is biased toward the kerf 63 as compared with the case of FIG. As a result, the groove 63 having a smaller friction coefficient is pressed against the shaft 90 more strongly than the hole 62 having a larger friction coefficient. For this reason, the difference in the frictional force between the shaft 90 and the hole 62 and the kerf 63 due to the resultant force F2 is smaller than that in the case of FIG. As a result, the movement of the holder 60 when a current is applied to the coil 20 is smoother than in the case of FIG.

  In FIG. 3C, the magnetic plate 32 is further arranged so that the center of the magnetic plate 32 approaches the kerf 63 from the center L2 of the magnet 70 in plan view. In this case, the resultant force F3 of the magnetic force generated between the magnetic plates 31 and 32 and the magnet 70 is further biased toward the kerf 63 as compared with the case of FIG. As a result, the kerf 63 with a small friction coefficient is pressed more strongly against the shaft 90 than the hole 62 with a large friction coefficient. For this reason, the difference in the frictional force between the shaft 90 and the hole 62 and the kerf 63 due to the resultant force F3 is further reduced as compared with the case of FIG. As a result, the movement of the holder 60 when a current is applied to the coil 20 becomes smoother than in the case of FIG.

  FIG. 5E is a diagram showing the verification result of the above effect. In the figure, A1, A2, and A3 correspond to the cases of (a), (b), and (c), respectively. As the verification results, the moving speed and the tilt amount of the holder when the same current (current in a direction to move the holder 60 upward from the home position) is applied to the coil in each case are shown. The tilt amount is the maximum tilt angle of the holder with respect to the reference surface of the base 10. Each value is a relative value with the value in A1 being 1.

  The verification conditions are as follows.

・ Vertical and horizontal dimensions of holder 60 in plan view: vertical and horizontal 7.6 mm
・ Height dimension of holder 60: 2 mm
-Weight of holder 60 as a whole: 0.5 g
・ Distance between shafts 90: 7.6 mm
・ Vertical and horizontal dimensions of the opposing surface of the magnet 70: 1.5 mm length, 4 mm width
・ Vertical and horizontal dimensions of magnetic plates 31 and 32: Vertical 2.3 mm, horizontal 2 mm
-Shift position of the magnetic plate 31 in A2: Arrange the magnetic plate 31 so that the end face of the shift direction of the magnetic plate 31 coincides with the end face of the magnet 70-Shift position of the magnetic plate 32 in A3: End face of the shift direction of the magnetic plate 32 The magnetic plate 31 is disposed so that the end face of the magnet 70 coincides with the diameter P of the shaft 90 (see FIG. 5B): 0.4 mm
-Depth Q of the hole 62 (see FIG. 5B): 1.5 mm
-Diameter R of the hole 62 (see FIG. 5B): 0.41 mm
-Depth 63 of the kerf 63 (see FIG. 6B): 1.5 mm
・ Gap T of the kerf 63 (see FIG. 6B): 0.41 mm
In the state of A3, the groove 63 having a smaller coefficient of friction than the hole 62 having a larger coefficient of friction is more strongly pressed against the shaft 90 by the resultant force F3, and the frictional force between the hole 62 and the groove 63 on the shaft 90 is substantially equal. It is even.

  From the verification result of FIG. 5E, both or one of the magnetic plates 31 and 32 is brought close to the groove 63, and the magnetic force between the magnetic plate and the magnet is biased toward the groove 63 having a smaller friction coefficient. This shows that the operating characteristics of the holder 60 are improved. In the present embodiment, as shown in FIG. 4, since both of the magnetic plates 31 and 32 are brought close to the cut groove 63, the holder 60 is smoothly moved when a current is applied to the coil 20. Can do. As a result, the characteristics of the autofocus function of the camera module can be improved.

  In the above embodiment, both of the magnetic plates 31 and 32 are brought close to the kerf 63, but either one may be made closer to the kerf 63. Also in this case, the movement characteristics of the holder 60 can be improved as shown in FIG.

  Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications can be made to the embodiment of the present invention other than the above.

  For example, in the above-described embodiment, one magnet 70 is arranged on one side of the holder 60, but two or more magnets may be arranged on each side. For example, as shown in FIG. 10, the magnets 70 arranged on the respective side surfaces may be arranged separately in two parallel to the corresponding side surfaces and in the direction around the optical axis of the lens. FIG. 4B is a perspective view of the holder 60 portion in this case, and FIG. 4A is a top view when the upper portion is removed by cutting the same FIG. In this configuration example, the shape of the base 10 is changed compared to the above embodiment. For example, as can be seen from FIG. 5B, the base 10 is not provided with a configuration for arranging the printed circuit board 40. A current is applied to the coil 20 via a terminal 41 in the figure.

  Referring to FIG. 5A, in this modification, two magnets 70 arranged on one side surface are arranged at a position away from the center of the side surface by a certain distance in plan view. Thus, the opening 61 can be enlarged by arranging the magnet 70 separately. Thereby, a larger lens can be mounted on the same size lens driving device, and the size of the lens driving device can be reduced if the lens size is the same.

  In addition, the magnetic plates 31 and 32 are arrange | positioned so that it may oppose on both sides of the coil 20 with respect to the magnet 70 near the cut groove 63 among the two magnets arrange | positioned at the corresponding side surface. As a result, like the above embodiment, the kerf 63 is pressed against the shaft 90 more strongly than the hole 62, and the holder 60 can be moved smoothly when a current is applied to the coil 20. .

  In the above embodiment, the two magnetic plates 31 and 32 are arranged on the base 10, but one or three or more magnetic plates may be arranged on the base 10. However, also in this case, the magnetic force generated between the magnet and the magnetic plate is unbalanced with respect to the optical axis of the lens, and the resultant force of the magnetic force is biased toward the groove 63 rather than the hole 62. A magnetic plate needs to be arranged.

  In the magnetic plate, for example, as in A3 of FIG. 9E, the frictional force between the shaft and the two engaging portions (in the above embodiment, the hole 62 and the cut groove 63) is uniform. It is most preferable to adjust the arrangement or shape thereof. If it carries out like this, since the frictional force applied to two engaging parts will become equal at the time of a movement of a holder, a holder can be moved most smoothly.

  In the above embodiment, the kerfs 63 absorb the positional deviation of the shaft 90, the formation error of the holes 63 or the kerfs 63, and the like. Alternatively, an elliptical hole or the like may be provided so as to absorb such positional deviation or formation error.

  Furthermore, the diameter of the shaft 90, the diameter, depth, and shape of the hole 62, and the gap, depth, and shape of the kerf 63 are not limited to those exemplified in the above-described embodiment and verification conditions. It can be changed. The dimensions and the like shown in the verification conditions are merely examples, and it is naturally possible to change the values of the parameters other than those exemplified above. Further, the shapes of the base 10, the holder 60, and the like are not limited to the above, and can be changed as appropriate. The diameters of the two shafts 90 may not be the same.

  In addition, the embodiment of the present invention can be variously modified as appropriate within the scope of the technical idea shown in the claims.

DESCRIPTION OF SYMBOLS 1 ... Lens drive device 10 ... Base 20 ... Coil 31, 32 ... Magnetic board 60 ... Holder 62 ... Hole (1st engaging part)
63 ... kerf (second engaging portion)
63b ... Wall surface (wall surface)
70 ... Magnet 90 ... Shaft 200 ... Image sensor (imaging device)
301 ... CPU (control unit)

Claims (6)

Base and
Two shafts with a circular cross section mounted on the base;
A holder that holds the lens and is supported by the shaft so as to be displaceable in the optical axis direction of the lens;
A magnet mounted on the holder;
A coil mounted on the base to face the magnet;
A magnetic plate disposed on the base side so as to face the magnet across the coil,
The holder is provided with a first engagement portion and a second engagement portion that engage with the two shafts, respectively, and the first engagement portion and the second engagement portion are the first engagement portion and the second engagement portion, respectively. A contact area between the first engaging portion and the shaft is configured to be larger than a contact area between the second engaging portion and the shaft;
In the magnetic plate, the magnetic force generated between the magnetic plate is unbalanced in a plane perpendicular to the optical axis of the lens, and the magnetic force is generated by the first engaging portion and the second engaging portion. The second engagement portion is configured so as to be applied more greatly.
A lens driving device. The lens driving device according to claim 1,
The first engaging portion is a hole having a circular cross section equal to or larger than the diameter of the corresponding shaft,
The second engaging portion is a pair of wall surfaces having a distance equal to or larger than the diameter of the corresponding shaft.
A lens driving device. The lens driving device according to claim 1,
The drive unit has a plurality of the magnets mounted on the holder,
The magnetic plate is arranged to face at least one of the plurality of magnets;
A lens driving device. The lens driving device according to claim 3,
The holder has an octagon in which two opposing sides are parallel to each other in plan view, and has a shape in which the center of the octagon coincides with the optical axis of the lens;
The four magnets are arranged on each of the four side surfaces that are not adjacent to each other among the eight side surfaces of the holder so that the center of each side surface matches the center of the magnet,
Two magnetic plates are arranged so as to face two adjacent magnets among the four magnets, and the center of these two magnetic plates is closer to the second engaging portion than the center of the corresponding magnet. The two magnetic plates are positioned so as to shift,
A lens driving device. The lens driving device according to claim 4,
The four magnets are respectively arranged on the corresponding side surfaces in parallel to the corresponding side surfaces and separated into two in the direction around the optical axis of the lens.
A lens driving device. A lens driving device according to claim 1;
An image sensor for receiving the light collected by the lens;
A control unit for applying a control signal of the coil,
A camera module characterized by that.

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