JP2015084003A - Lens actuator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lens actuator mainly used for camera and electronic apparatus such as mobile phone capable of reducing undesired resonance.SOLUTION: A lens actuator 100 includes plural guide balls 67 disposed between a lens holder 61 and a fixed holder 63 to ensure a predetermined distance between a lens holder 61 and a fixed holder 63. When an electronic apparatus is subjected to a camera shake, since undesired resonance generated on the lens holder 61 is reduced, shake correction control is carried out at a high speed.

Description

  The present invention relates to a lens actuator mainly used in electronic devices such as cameras and mobile phones.

  In electronic devices such as cameras and mobile phones, there has been proposed a lens actuator provided with a shake correction drive unit capable of suppressing image distortion due to camera shake during shooting.

  Such a conventional lens actuator will be described with reference to FIGS.

  Here, FIG. 11 is a sectional perspective view of a conventional lens actuator 30, and FIG. 12 is an exploded perspective view thereof. This lens actuator 30 includes a movable portion 1 and a fixed portion 2, and when the hand shake or the like occurs, the movable portion 1 is tilted to suppress disturbance of an image or an image.

  First, the movable part 1 will be described.

  The movable unit 1 includes an autofocus unit 11, a holding unit 12, and an imaging unit 13.

  The autofocus unit 11 includes a fixed holder 14, a first magnet 15 disposed in the fixed holder 14, a lens holder 16 movable in the vertical direction with respect to the fixed holder 14, and a first holder disposed in the lens holder 16. A coil 17 and a leaf spring 18 for connecting the fixed holder 14 and the lens holder 16 are provided.

  Here, the first magnet 15 is fixed to the fixed holder 14 side by side in two stages on the front, rear, left and right inner surfaces.

  The lens holder 16 includes a circular hole 16A in which the lens is fixed, and is stored inside the fixed holder 14. The lens holder 16 has a first coil 17 wound around the outer periphery thereof in two upper and lower stages, and the first coil 17 faces the first magnet 15 disposed on the inner surface of the fixed holder 14. Yes.

  Then, the lens holder 16 moves up and down with respect to the fixed holder 14 by the electromagnetic force generated between the first magnet 15 and the first coil 17 to perform autofocus control.

  Here, the leaf spring 18 has an outer peripheral portion connected to the fixed holder 14, an inner peripheral portion connected to the lens holder 16, and the lens holder 16 is operated smoothly with respect to the fixed holder 14.

  The holding unit 12 has a second magnet 19 disposed on the outer surface.

  Further, an image pickup device 20 is disposed on the upper surface of the image pickup unit 13. The image pickup device 20 is located below the center of the circular hole 16A, and by moving the lens holder 16 up and down, autofocus control can be performed to automatically adjust the image captured by the image pickup device 20 or the focus of the image.

  Next, the fixing part 2 will be described.

  The fixed portion 2 includes a second coil 21, four coil holders 22, a lower cover 23, four suspension wires 24, and an upper cover 25.

  The suspension wire 24 is connected to the four corners of the lower cover 23 and the four corners of the holding unit 12 of the movable part 1, and the movable part 1 is tiltably held on the lower cover 23. Furthermore, the coil holding body 22 is disposed on the front, rear, left, and right sides of the movable portion 1, and the second coil 21 is disposed in a state of facing the second magnet 19.

  That is, the lens actuator 30 is held by the four suspension wires 24 so that the movable portion 1 can tilt. When a shake such as a hand shake occurs, an electric current is passed through the second coil 21 to cause an electromagnetic force generated between the second coil 21 and the second magnet 19 constituting the shake correction drive unit. The movable part 1 is tilted.

  When the lens actuator 30 is shaken due to camera shake or the like when the electronic device is used, shake correction control is performed to correct the photographed image by tilting the movable portion 1.

  As prior art document information related to the invention of this application, for example, Patent Document 1 is known.

International Publication No. 2009/133691

  However, when the conventional lens actuator performs shake correction control, the leaf spring may cause unnecessary resonance, and shake correction control may take time, or the accuracy of shake correction control may be reduced.

  The present invention solves such a conventional problem, and an object thereof is to provide a lens actuator capable of reducing unnecessary resonance.

  In order to achieve the above object, in the present invention, in particular, a lens actuator is configured by arranging a plurality of guide balls between a lens holder and a fixed holder.

  According to the present invention, since a plurality of guide balls are arranged between the lens holder and the fixed holder, the lens holder and the fixed holder can maintain a predetermined distance, and unnecessary resonance is performed during shake correction control. Can be provided.

1 is an exploded perspective view of a lens actuator according to Embodiment 1 of the present invention. Cross section of the lens actuator Partial cutaway perspective view of the lens actuator Detailed exploded perspective view of the lens actuator Sectional view from above of lens actuator Sectional view from the side of the lens actuator FIG. 6 is an exploded perspective view of a lens actuator according to Embodiment 2 of the present invention. Detailed exploded perspective view of the lens actuator The perspective view which compares the base member used for Embodiment 1 of this invention with the base member used for Embodiment 2 of this invention The figure explaining the flow of the electric current of the lens actuator by Embodiment 2 of this invention. Cross-sectional perspective view of a conventional lens actuator Exploded perspective view

(Embodiment 1)
Hereinafter, the lens actuator according to the first embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is an exploded perspective view of a lens actuator 100 according to an embodiment of the present invention, and FIG. Here, the lens actuator 100 includes a fixed portion 31, a movable portion 32 that tilts within the fixed portion 31, and a tilt spring 33 that connects the fixed portion 31 and the movable portion 32.

  The lens actuator 100 has, for example, a width in the left-right direction (Y-axis direction) of 5 mm to 20 mm, a depth in the front-rear direction (X-axis direction) of 5 mm to 20 mm, and a height in the vertical direction (Z-axis direction) of 2 mm to 10 mm. The width in the left-right direction and the depth in the front-rear direction are substantially the same.

  Next, the configuration of the fixed portion 31, the movable portion 32, and the tilt spring 33 will be described.

  The fixing portion 31 includes a cover 41, a control block 42 accommodated in the cover 41, and a bottom plate 43 disposed on the lower surface of the control block 42.

  Here, the cover 41 has a circular hole 41A on the upper surface, and is configured in a rectangular box shape with the lower surface open.

  The control block 42 has a square hole 42A in the center and is formed in a rectangular cylinder shape. Here, a plurality of electronic components are arranged on the inner side surface and the outer side surface of the control block 42 and are electrically connected to each other. The control block 42 is accommodated in the cover 41. The movable portion 32 is disposed in the square hole 42A.

  The bottom plate 43 is formed in a square plate shape. The bottom plate 43 is disposed so as to cover the opening surface of the cover 41 from below the movable portion 32.

  Next, the movable portion 32 includes a cylindrical lens barrel 51 in which a plurality of lenses are arranged, an autofocus unit 52 that houses the lens barrel 51, and a cover glass 53 that is disposed below the lens barrel 51. The imaging unit 54 is provided below the cover glass 53.

  A lens is fixedly disposed inside the lens barrel 51. For example, 3 to 5 lenses are arranged in the optical axis direction.

  The autofocus unit 52 has a circular hole 52A in the center, and holds the lens barrel 51 in the circular hole 52A. Here, the autofocus unit 52 includes an autofocus drive unit that moves the lens barrel 51 in the optical axis direction of the lens disposed inside the lens barrel 51.

  Further, the cover glass 53 is disposed in the optical axis direction of the lens barrel 51. The cover glass 53 may be provided with a filter function such as absorbing infrared rays.

  The imaging unit 54 includes a wiring board 55, a solid-state imaging element 56, and a first magnetic field detection element 57.

  Here, the wiring board 55 is wired on the upper and lower surfaces, and electronic components such as capacitors and resistors arranged on the upper surface and the solid-state imaging device 56 are electrically connected. Further, a connector portion 55A for outputting a signal to the outside is formed at one end of the wiring board 55. Further, a part of the wiring board 55 is bent upward to form an auxiliary board portion 55B. A first magnetic field detection element 57 is disposed at the inner tip of the bent auxiliary substrate portion 55B.

  The solid-state imaging element 56 is an integrated circuit of photoelectric conversion elements, and for example, a semiconductor element such as a CCD (Charge Coupled Device) image sensor or a CMOS (Complementary Metal Oxide Semiconductor) image sensor is used. The solid-state image sensor 56 digitizes the captured image and outputs it as an image signal.

  Further, the first magnetic field detection element 57 is disposed to face the autofocus unit 52. The first magnetic field detection element 57 is an element that detects a magnetic field, such as a Hall element, and outputs a magnetic field detection signal.

  That is, the movable unit 32 is configured such that light incident from the lens barrel 51 is imaged by the solid-state image sensor 56 through the cover glass 53 and is output as an image signal from the solid-state image sensor 56.

  The tilt spring 33 is a metal spring such as a leaf spring configured in a predetermined shape. Here, the tilt spring 33 has a square hole 33A at the center, and connects the fixed portion 31 and the movable portion 32 at the outer periphery and the inner periphery. Here, when the movable portion 32 tilts with respect to the fixed portion 31, the tilt spring 33 is configured to bend.

  Here, the connection state of the tilt spring 33 with respect to the fixed portion 31 and the movable portion 32 will be described with reference to FIG. The movable portion 32 is disposed inside the square hole 33 </ b> A of the tilt spring 33, and the inner periphery of the tilt spring 33 is fixed to the outer periphery of the autofocus unit 52. More specifically, the inner circumference of the tilt spring 33 is connected to the outer circumference of a base member 68 described later.

  Further, the outer periphery of the tilt spring 33 is fixed to the fixing portion 31. More specifically, the outer periphery of the tilt spring 33 is connected to the inner periphery of a frame 75 described later so as to match the upper end of the rectangular groove 75D.

  For example, fixing between the tilt spring 33 and the autofocus unit 52 is performed by an adhesive, and fixing between the tilt spring 33 and the frame 75 is performed by welding.

  The tilt spring 33 connects the fixed portion 31 and the movable portion 32, and the tilt of the movable portion 32 with respect to the fixed portion 31 is performed with the X-axis direction and the Y-axis direction as central axes.

  The overall configuration of the lens actuator 100 is as described above.

  Here, the configuration of the autofocus unit 52 and the control block 42 will be described in more detail using the exploded perspective view of FIG.

  First, the autofocus unit 52 will be described.

  The autofocus unit 52 includes a lens holder 61, a first magnet 62 disposed in the lens holder 61, a fixed holder 63 in which the lens holder 61 is accommodated, a first coil 64 disposed in the fixed holder 63, A suction yoke 65, a second magnet 66, a plurality of guide balls 67 disposed between the lens holder 61 and the fixed holder 63, and a base member 68 are provided.

  Here, the lens holder 61 is made of, for example, an insulating resin such as glass-containing polycarbonate, and includes a circular hole 61A penetrating vertically in the center, and is formed in a rectangular cylinder shape. Guide grooves 61B are formed on the left and right ends of the lens holder 61, respectively. The circular hole 61A may have a constant diameter or may change. Moreover, you may provide shapes, such as a screw for fixing a lens inside.

  The first magnet 62 is a magnet in which different magnetic poles are magnetized on the upper and lower sides. The first magnet 62 is disposed on only a total of two side surfaces, one of the side surfaces in the front-rear direction and the one side surface in the left-right direction of the lens holder 61, and is fixed to the lens holder 61.

  One of the two first magnets 62 faces the first magnetic field detection element 57, and the electromagnetic field radiated by the first magnet 62 is detected by the first magnetic field detection element 57. The

  The fixed holder 63 is made of, for example, an insulating resin such as glass-filled polycarbonate, and has four column portions 63C extending downward from the respective corners of the square top plate portion 63B provided with the circular holes 63A. Is done. Here, a guide groove 63D is formed in the vertical direction in the two pillar portions 63C at the diagonal positions.

  The lens holder 61 is arranged inside the column portion 63C of the fixed holder 63 so as to be movable up and down.

  The first coil 64 is formed, for example, by winding a coil wire having a wire diameter of Φ40 μm to Φ60 μm with the front-rear direction or the left-right direction as an axis, and is in contact with the outer surface of the column portion 63C. Here, the first coil 64 is disposed at a position facing the lens holder 61 and the first magnet 62 fixed. For this reason, when a current is passed through the first coil 64, the lens holder 61 and the first magnet 62 are integrated and can be moved up and down by electromagnetic force in the fixed holder 63.

  The second magnet 66 is a magnet in which different magnetic poles are magnetized on the upper side and the lower side of the side surface. The second magnet 66 is disposed only on a total of two side surfaces of either one of the side surfaces in the front-rear direction and the side surface in the left-right direction of the fixed holder 63, and is fixed to the fixed holder 63.

  The first magnet 62 and the second magnet 66 are neodymium magnets, which are rare earth magnets mainly composed of neodymium, iron, and boron. Although a magnet other than a neodymium magnet can be used, a neodymium magnet is more preferable because it has a large magnetic force. Further, it is desirable to use a neodymium magnet having a holding power of 500 kA / m to 3000 kA / m and a residual magnetic flux density of 1.3 to 1.5 T.

  Further, since the first magnet 62 and the second magnet 66 are magnets having different magnetic poles on the upper side and the lower side of the side surface, the generated magnetic field can be rectified to generate a stronger magnetic field. It has become a structure.

  The plurality of guide balls 67 are disposed between the lens holder 61 and the fixed holder 63, and rotate when the position of the lens holder 61 changes with respect to the fixed holder 63. The guide ball 67 preferably has a diameter of 0.5 mm to 1.5 mm, and is made of a metal such as stainless steel, a resin, a ceramic, or the like.

  Here, the arrangement of the guide ball 67 will be described in more detail using the cross-sectional views of FIGS. 5 and 6.

  As shown in FIG. 5, the guide ball 67 is disposed between the guide grooves 61 </ b> B provided at two left and right locations and the guide grooves 63 </ b> D provided at two right and left locations. Here, in order for the lens holder 61 to suppress vibration in the front-rear and left-right directions in the fixed holder 63, the contact point of the guide ball 67 with respect to the guide groove 61B and the guide groove 63D may be one point or two points for each. preferable. For example, in the arrangement shown in the figure, the guide ball 67 is in contact with the guide groove 61B at two points A1 and A2, and is in contact with the guide groove 63D at two points B1 and B2. That is, the guide ball 67 is in contact with the lens holder 61 and the fixed holder 63 at two points, for a total of four points. In addition, it is desirable to contact at a total of four points on one side (for example, the right side) guide grooves 61B and 63B, and to contact at a total of three points on the opposite side (for example, the left side) guide grooves 61B and 63B. This is because the contact position is stabilized even if dimensional variations in manufacturing occur.

  Further, as shown in FIG. 6, two guide balls 67 are arranged with respect to the two guide grooves 61B and the two guide grooves 63D provided diagonally in a top view, and a total of four guide balls 67 are arranged. Here, when the centers of the four guide balls 67 are connected and a virtual area S as shown in FIG. 4 is set, the larger the area of the virtual area S suppresses vibrations of the lens holder 61 in the front-rear and left-right directions with respect to the fixed holder 63. it can. For this reason, it is desirable to provide the guide groove 61B and the guide groove 63D diagonally in the top view of the lens holder 61 and the fixed holder 63.

  The guide ball 67 can be arranged as long as at least the area of the virtual region S can be secured. That is, the guide balls 67 may be three or more, and the virtual region S connecting the centers thereof may have an area, in other words, the virtual region S may be an arrangement that forms a polygon.

  The suction yoke 65 is disposed outside the first coil 64 and is fixed to the fixed holder 63. Here, the attracting yoke 65 is formed of a ferromagnetic material such as iron in the shape of a square plate. By facing the first magnet 62, the first magnet 62 is attracted to the attracting yoke 65 by a magnetic force. Thereby, the lens holder 61 is pressed against the fixed holder 63, and vibrations in the front-rear and left-right directions of the guide ball 67 are further suppressed.

  Next, the control block 42 will be described.

  The control block 42 includes a spacer 71, a wiring substrate 72, a shake detection element 73 disposed on the wiring substrate 72, and a control circuit 74 disposed on the wiring substrate 72.

  Further, the control block 42 includes a frame 75 on which the wiring board 72 is disposed, a second coil 76 disposed on a side surface of the frame 75, a shake correction board 77 on which the second coil 76 is disposed, and a shake correction. A second magnetic field detection element 78 disposed on the substrate 77 is provided.

  Here, the spacer 71 has a rectangular frame shape and has a predetermined thickness.

  Moreover, the wiring board 72 is comprised with a flexible printed wiring board, for example.

  The shake detection element 73 is an element that detects shake, such as an angular velocity sensor or an acceleration sensor, and outputs a shake signal. Here, when a biaxial angular velocity sensor is arranged as the shake detection element 73, for example, the angular velocity in which one axis is in the yaw direction and the other axis is in the pitch direction is detected. For example, when a biaxial acceleration sensor is arranged as the shake detection element 73, one axis detects acceleration in the front-rear direction and the other axis detects left-right acceleration. Note that the shake detection element 73 may not be biaxial, but may be provided with a plurality of uniaxial shake detection elements, or may be triaxial. When a plurality of shake detection elements are provided, one is an angular velocity sensor. Another type of sensor may be arranged such that the other is an acceleration sensor.

  Furthermore, the control circuit 74 is a semiconductor element such as an IC (Integrated Circuit). The control circuit 74 is electrically connected to the shake detection element 73 and receives a shake signal. Then, the control circuit 74 calculates the tilt angle of the control block 42 based on the shake signal, controls the tilt of the movable portion 32, and performs shake correction control.

  The frame 75 is made of a conductive metal and is formed in a square cylinder shape. The frame 75 includes an outer surface 75A and an inner surface 75B, a square hole 75C is formed on the upper surface, and a square groove 75D is formed on the outer surface 75A. Then, the wiring board 72 is bent and disposed on the three surfaces of the outer surface 75A.

  The second coil 76 is formed by winding a coil wire having a wire diameter of Φ40 μm to Φ60 μm with the front-rear direction or the left-right direction as an axis. The second coil 76 is disposed facing the inner side surface 75 </ b> B and is housed in the frame 75. In addition, as a coil wire which forms the 2nd coil 76, enamel wires, such as a polyurethane copper wire, a polyester copper wire, and a polyamide-type copper wire, are preferable.

  The shake correction board 77 is, for example, a flexible printed wiring board, is bent at a right angle, faces the inner side surface 75B, and is disposed at a position below the second coil 76.

  And the 2nd magnetic field detection element 78 is arrange | positioned on the two surfaces corresponding to the front-back direction and the left-right direction of the shake correction board | substrate 77, respectively. The second magnetic field detection element 78 is an element that detects a magnetic field, such as a Hall element, and outputs a magnetic field detection signal.

  The second coil 76 and the second magnetic field detection element 78 are electrically connected to the control circuit 74 via the wiring of the shake correction board 77.

  The lens actuator 100 configured as described above is built in an electronic device such as a mobile phone, and is disposed on a wiring board (not shown) of the electronic device. The electronic device is used when taking an image using a camera function.

  When photographing or imaging is performed using the lens actuator 100, the lens actuator 100 performs autofocus control and shake correction control.

  When performing autofocus control, a current flows through the first coil 64. Then, the lens holder 61 in which the lens barrel 51 is inserted moves up and down to perform autofocus control.

  At this time, the control circuit 74 uses the image data input from the solid-state image sensor 56 to determine the position where the lens holder 61 moves. The first magnetic field detection element 57 detects the magnetic field radiated by the first magnet 62, and the lens holder 61 reaches a desired position based on the magnetic field detection signal output from the first magnetic field detection element 57. The control circuit 74 controls the current that flows through the first coil 64.

  In addition, when the lens holder 61 moves up and down with respect to the fixed holder 63, the guide ball 67 serves as a bearing so that the lens holder 61 is smoothly operated.

  Further, when shake correction control is performed, a shake signal output from the shake detection element 73 is input to the control circuit 74, and the control circuit 74 performs a tilt angle of the movable portion 32 according to a predetermined algorithm based on the shake signal. Is calculated.

  Then, the control circuit 74 causes an electric current to flow through the second coil 76, generates an electromagnetic force with the second magnet 66 disposed in the autofocus unit 52, and tilts the movable portion 32.

  Here, the magnetic field of the second magnet 66 is detected by the second magnetic field detection element 78, and the control circuit 74 determines the desired tilt angle based on the magnetic field detection signal output from the second magnetic field detection element 78. The movable part 32 is controlled.

  In the lens actuator 100, since the distance between the lens holder 61 and the fixed holder 63 is maintained at a predetermined distance by the guide ball 67 during shake correction control, unnecessary vibration of the lens holder 61 is suppressed. From this, it is possible to reduce the time of shake correction control or improve the accuracy of shake correction control.

  Note that the autofocus unit 52 alone has the effect of suppressing unnecessary vibration of the lens holder 61 by keeping the distance between the lens holder 61 and the fixed holder 63 at a predetermined distance by the guide ball 67. Thereby, it is possible to shorten the time of autofocus control or improve the accuracy of autofocus control.

  In the above description, the example in which the autofocus drive unit is configured using the electromagnetic force generated between the first magnet 62 and the first coil 64 has been described. However, as other examples, a shape memory alloy, a piezoelectric element, and the like are used. It is also possible to configure the autofocus drive unit using another actuator such as an electrostatic actuator.

  Furthermore, the example in which the shake correction drive unit is configured using the electromagnetic force generated between the second magnet 66 and the second coil 76 has been shown. Other examples include shape memory alloys, piezoelectric elements, electrostatic It is also possible to configure the shake correction drive unit using another actuator such as an actuator.

  It should be noted that the present invention can be implemented even in an arrangement in which the arrangement relationship between the first magnet 62 and the first coil 64 is exchanged, and in an arrangement in which the arrangement relationship between the second magnet 66 and the second coil 76 is exchanged. The invention can be implemented.

  That is, the present invention can be implemented even when the first magnet 62 is fixed to the fixed holder 63 and the first coil 64 is fixed to the lens holder 61. The present invention can also be implemented by fixing the second magnet 66 to the frame 75 and fixing the second coil 76 to the fixing holder 63.

  Further, the image photographed by the lens actuator 100 may be a still image or a moving image.

  In the above description, the configuration in which the first magnet 62 is arranged on the side surface of the lens holder 61 and the second magnet 66 is arranged on the side surface of the fixed holder 63 has been described, but the first magnet 62 and the second magnet 66 are arranged. The structure arrange | positioned at each corner position may be sufficient.

  In addition, the first magnetic field detection element 57 and the second magnetic field detection element 78 have been described as examples of the position detection elements for detecting the positions of the lens holder 61 and the movable portion 32, but a photo reflector using infrared reflection, etc. An element using a method other than magnetic field detection may be used.

  Note that the autofocus control method may be controlled using only image information. In this case, since the first magnetic field detection element 57 can be omitted, the auxiliary substrate part 55B for transmitting the magnetic field detection signal for autofocus control can be omitted, which is preferable for low-cost production.

  In addition, an example in which the tilting spring 33 is used to support the movable portion 32 so that the movable portion 32 can tilt with respect to the fixed portion 31 has been shown. However, by providing a convex portion on the bottom surface of the movable portion 32, It is also possible to support the movable part 32 so that it can tilt.

  Moreover, there is no restriction | limiting in the number of the 1st magnet 62, the 1st coil 64, the 2nd magnet 66, and the 2nd coil 76, For example, it is also possible to arrange | position four each.

  When the first magnet 62 is disposed in the lens holder 61 and the second magnet 66 is disposed in the fixed holder 63, the magnetic force between the first magnet 62 and the second magnet 66 is controlled by autofocus control and vibration. In order to reduce the influence on the correction control, it is desirable to arrange the two first magnets 62 and the two second magnets 66 at positions where they do not face each other, as described in the present embodiment. .

  As described above, according to the present embodiment, since the plurality of guide balls 67 are arranged between the lens holder 61 and the fixed holder 63, the lens holder 61 and the fixed holder 63 can maintain a predetermined interval. It is possible to provide the lens actuator 100 capable of high-speed shake correction control by reducing unnecessary resonance generated in the lens holder 61 when the electronic device is shaken.

  Further, since there are three or more guide balls 67 and are arranged so as to form a virtual region S when the centers of the guide balls 67 are connected, the positional relationship of the lens holder 61 with respect to the fixed holder 63 can be defined. Suitable for reducing unnecessary resonance.

  Further, since the position of the guide ball 67 is projected on a plane orthogonal to the optical axis direction of the lens, the guide ball 67 is disposed on the diagonal line of the fixed holder 63. Therefore, the area of the virtual region S connecting the centers of the guide balls 67 can be increased and is unnecessary. It is suitable for reducing the resonance.

  Further, by using the tilt spring 33, the positional relationship of the movable part 32 with respect to the fixed part 31 can be stabilized.

(Embodiment 2)
Hereinafter, the lens actuator 200 according to Embodiment 2 of the present invention will be described with reference to FIGS.

  In the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  Here, the lens actuator 200 includes a fixed portion 131, a movable portion 132, a plurality of suspension wires 133 that connect the fixed portion 131 and the movable portion 132, and a connection substrate 134 that connects the fixed portion 131 and the movable portion 132. Configured.

  The lens actuator 200 is mainly different from the lens actuator 100 in that shake correction control is performed by using the suspension wire 133 and the movable portion 132 moving in parallel back and forth and right and left with respect to the fixed portion 131.

  First, the fixing unit 131 includes a cover 141, a control block 142 accommodated in the cover 141, and a bottom plate 143 disposed on the lower surface of the control block 142.

  Here, the cover 141 has a circular hole 141A on the upper surface, and is configured in a rectangular box shape with the lower surface open.

  Further, the control block 142 has a storage portion 142A inside, and is configured in a rectangular cylinder shape. Here, a plurality of electronic components are arranged on the inner side surface and the outer side surface of the control block 142 and are electrically connected to each other. The control block 142 is accommodated in the cover 141. And the movable part 132 is arrange | positioned in 142 A of accommodating parts.

  The bottom plate 143 is formed in a square plate shape. The bottom plate 143 is disposed so as to cover the opening surface of the cover 141 from below the movable portion 132.

  Next, the movable portion 132 includes a lens barrel 51 having a cylindrical shape and a plurality of lenses disposed therein, and an autofocus unit 152 that houses the lens barrel 51.

  The autofocus unit 152 has a circular hole 152A at the center, and the lens barrel 51 is accommodated in the circular hole 152A. Here, the autofocus unit 152 includes a moving mechanism that moves the lens barrel 51 in the optical axis direction of the lens disposed inside the lens barrel 51.

  Next, the control block 142 and the autofocus unit 152 will be described with reference to FIG. The suspension wire 133 and the connection substrate 134 will be described together.

  The control block 142 includes a wiring board 172, a frame 175 on which the wiring board 172 is disposed, and a second coil 176 disposed on a side surface of the frame 175.

  Here, since the wiring board 172 is formed by folding a plurality of times, a flexible wiring board is suitable. In addition, the second magnetic field detection element 178 is provided on each of the two surfaces of the wiring board 172 facing the second magnet 66. When performing shake correction control, the second magnetic field detection element 178 detects the magnetic field of the second magnet 66, and based on the magnetic field detection signal output from the second magnetic field detection element 178, the movable portion 132. The amount of movement of the front, rear, left and right is controlled.

  One end of the wiring board 172 constitutes a connector portion 172A for transmitting / receiving signals to / from the outside of the lens actuator 200 and supplying current to the lens actuator 200. In FIG. 8, the connector is omitted. In addition, electrodes 172B are formed in the shape of through holes on the four sides of the upper surface of the wiring board 172, and are electrically connected to the connector portion 172A.

  Further, the frame 175 is formed in a rectangular frame shape. Here, the wiring board 172 is disposed on the frame 175, and the second coil 176 is disposed on the outer surface of the frame 175. The second coil 176 is electrically connected to the electrode 172B of the wiring board 172.

  Further, the autofocus unit 152 according to the present embodiment is the same as the autofocus unit 52 according to the first embodiment except that the base member 68 is changed to the configuration of the base member 168.

  9A, the base member 68 (see) of the first embodiment is compared with the base member 168 of the present embodiment in FIG.

  Here, the base member 68 is made of an insulating material such as an insulating resin, whereas the base member 168 includes a base 181 made of an insulating material and a pair of left and right wiring boards 182 made of a conductive material. . Note that holes 182A are provided at the four ends of the wiring board 182.

  The suspension wire 133 has one end connected to the hole 182A and the other end connected to the electrode 172B of the wiring board 172. As the suspension wire 133, for example, a metal wire having a diameter of 50 μm or more and less than 110 μm is used, and when the movable part 132 moves back and forth and right and left, the suspension wire 133 is also deformed to keep the movable part 132 horizontal. A suitable material for the suspension wire 133 is beryllium copper wire or phosphor bronze wire.

  Here, the current flowing through the first coil 64 in the autofocus unit 152 will be described with reference to FIG.

  As shown in the figure, both ends of the first coil 64 in the autofocus unit 152 are connected to the wiring board 182. Here, the left and right wiring boards 182 are electrically connected via the first coil 64.

  When a current flows through the first coil 64, a current is supplied from the outside of the lens actuator 200 via the wiring board 172, and a current flows through the electrode 172B to the right suspension wire 133 in FIG. (See arrow A). Then, a current flows from the suspension wire 133 to the first coil 64 via the wiring board 182 on the right side in the drawing (see arrow B). Further, a current flows from the first coil 64 to the left wiring board 182 in the drawing (see arrow C). Further, current is circulated from the wiring board 182 to the wiring board 172 via the left suspension wire 133 in the drawing (see arrow D).

  The connection board 134 connects the autofocus unit 152 and the wiring board 172, and the first magnetic field detection element 157 is disposed at a position facing the autofocus unit 152. Here, the magnetic field detection signal output from the first magnetic field detection element 157 is used to detect the position of the lens holder 61 in the autofocus unit 152.

  The lens actuator 200 configured as described above is built in an electronic device such as a mobile phone, and is disposed on a wiring board (not shown) of the electronic device. The electronic device is used when taking a still image or moving image using a camera function.

  A control circuit (not shown) and a shake detection element (not shown) are arranged on the wiring board of the electronic device.

  Then, the control circuit performs autofocus control and shake correction control when performing shooting or imaging using the lens actuator 200.

  Note that the autofocus control method may be controlled using only image information. In this case, since the first magnetic field detection element can be omitted, the connection substrate 134 for transmitting the magnetic field detection signal for autofocus control can be omitted, which is preferable for low-cost production.

  Thus, according to the present embodiment, the autofocus unit 152 using the guide ball 67 can also be used when performing shake correction control using the suspension wire 133.

  Further, by using the suspension wire 133, the positional relationship of the movable part 132 with respect to the fixed part 131 can be stabilized.

  Note that, as a holding mechanism for holding the positional relationship between the fixed portion and the movable portion at a predetermined position, a case other than the one using the tilt spring described in the first embodiment or the one using the suspension wire 133 described in the second embodiment is used. However, the present invention can be implemented by using the guide ball 67 for driving the lens holder 61 in the autofocus unit.

  The lens actuator according to the present invention can reduce unnecessary resonance, and is mainly useful for lens operation of electronic devices such as cameras and mobile phones.

31, 131 Fixed part 32, 132 Movable part 33 Tilt spring 33A Square hole 41, 141 Cover 41A, 141A Circular hole 42, 142 Control block 42A Square hole 51 Lens barrel 52, 152 Autofocus unit 52A, 152A Circular hole 53 Cover glass 54 Imaging unit 55 Wiring board 55A Connector part 55B Auxiliary board part 56 Solid-state imaging element 57, 157 First magnetic field detection element 61 Lens holder 61A Circular hole 61B Guide groove 62 First magnet 63 Fixed holder 63A Circular hole 63B Top plate part 63C Column 63D Guide groove 64 First coil 65 Adsorption yoke 66 Second magnet 67 Guide ball 71 Spacer 72, 172 Wiring board 73 Vibration detection element 74 Control circuit 75, 175 Frame 75A Outer surface 75B Inner surface 75C Square hole 5D square grooves 76, 176 second coil 77 shake compensation board 78,178 second magnetic field detecting elements 100 and 200 lens actuator 133 suspension wires 134 connect the substrate 142A accommodating portion 172A connector 172B electrode 181 base 182 wiring board 182A holes

Claims (5)

A lens holder that can hold a lens, a fixed holder in which the lens holder is accommodated, an autofocus driving unit that changes the position of the lens holder with respect to the fixed holder, and an arrangement between the lens holder and the fixed holder A guide ball that rotates when the position of the lens holder changes relative to the fixed holder, a shake correction holder that houses the lens holder, the fixed holder, and the autofocus driving unit, and a position of the fixed holder A lens actuator including a shake correction drive unit that changes the shake correction holder. The lens actuator according to claim 1, wherein there are three or more guide balls, and the guide balls are arranged to form a polygon when connecting the centers of the guide balls. The lens actuator according to claim 1, wherein the position of the guide ball is disposed on a diagonal line of the fixed holder when projected onto a plane orthogonal to the optical axis direction of the lens. The lens actuator according to claim 1, further comprising a tilt spring connected directly or indirectly to the fixed holder and the shake correction holder. The lens actuator according to claim 1, further comprising a suspension wire connected directly or indirectly to the fixed holder and the shake correction holder.

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