JP2015175879A - lens driving device and imaging device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lens driving device capable of miniaturizing a whole device, easily increasing the diameter of a lens, improving the position detecting characteristics of the lens, and easily assembling a magnetic position detecting member and an imaging device.SOLUTION: A lens driving device 10 includes: a lens holding frame 4 for holding a lens 55; an actuator 3 for moving the lens holding frame 4 in an optical axis direction; a magnet 81 fixed to the lens holding frame 4; a casing 1 for holding the actuator 3; and a hall element 82 fixed to the casing 1 for detecting the position of the magnet 81. The hall element 82 is arranged so as to be overlapped with a part or whole part of the magnet 81 when viewed from the optical axis direction.

Description

  The present invention relates to a lens driving device and an imaging device that can be suitably mounted on a mobile phone or the like.

  In recent years, a lens driving device that can be mounted on a cellular phone or the like is equipped with a lens position detection mechanism to enable faster and more accurate autofocusing.

  For example, Patent Document 1 includes a lens holding frame, a housing that accommodates the lens holding frame so as to be movable in the optical axis direction, and a lens position detection mechanism that includes a magnet and a Hall element (magnet position detection member). In the case, the magnet is fixed to the outer periphery of the lens holding frame, and the Hall element is fixed to the case so as to be opposed to the magnet at a distance outside the radial direction of the lens holding frame orthogonal to the optical axis direction. An imaging device is disclosed.

  Further, Patent Document 2 includes a lens barrel, a housing in which the lens barrel is movably accommodated in the optical axis direction, and a lens position detection mechanism having a magnet and a hall element, and the magnet is disposed on the outer periphery of the lens barrel. There is disclosed a camera module in which a Hall element is fixed to a housing so as to be opposed to the magnet on the outer side in the radial direction of a lens barrel perpendicular to the optical axis direction.

Japanese Patent No. 4880309 JP2011-197626A

However, Patent Document 1 and Patent Document 2 have the following problems.
That is, in Patent Document 1 and Patent Document 2, since the Hall element is fixed to the housing and the housing so as to be opposed to the outside in the radial direction perpendicular to the optical axis direction with respect to the magnet, the lens position The size of the housing or housing as viewed from the optical axis direction of the lens, that is, the installation area is increased by the detection mechanism, and as a result, the entire apparatus is increased in size and when the lens is increased in diameter, the housing is further increased. The size of the body and housing will increase, making it difficult to increase the diameter of the lens.

  In addition, the Hall element is electrically connected to the circuit board mounted with the image sensor and the peripheral circuit and attached to the image side of the lens, and electrical connection to the outside of the Hall element may be performed on the image side of the lens. Many. In many cases, since the electrical signal from the Hall element is a minute analog signal, it is vulnerable to noise and is required to be connected to a circuit (for example, an amplifier) with a short wiring distance. However, if the Hall element is attached to the outside in the radial direction of the magnet as in Patent Document 1 and Patent Document 2, a wiring member (for example, FPC) to the circuit board or an external electrical connection portion is required. It is difficult to shorten the wiring, and as a result, it is easy to receive noise, and there is a possibility that the lens position detection accuracy and controllability are deteriorated.

  Furthermore, since the Hall element is attached to the outside in the radial direction of the magnet via the wiring member (for example, FPC), the outer shape accuracy and mounting accuracy of the wiring member, for example, FPC, affect the mounting accuracy of the Hall element. Further, there is a concern that the position detection characteristic is likely to change due to temperature and time, and the position detection characteristics change.

  Further, since the Hall element is attached to the outer side in the radial direction of the magnet together with the wiring member, it is attached from the direction orthogonal to the lens optical axis of the housing, which makes it difficult to cope with the deterioration of assembling workability, in particular, the assembly automation. . In addition, the Hall element is usually mounted in advance on an FPC or the like which is a wiring member, and is difficult to handle than a single package of the Hall element, which makes it difficult to cope with the deterioration of assembly workability, in particular, the assembly automation.

  The present invention provides a lens driving device and an imaging device that can reduce the size of the entire device, easily increase the diameter of the lens, and improve the position detection characteristics of the lens, and can easily assemble a magnet position detection member. With the goal.

  The lens driving device of the present invention includes a lens holding frame that holds one or more lenses, an actuator that moves the lens holding frame in the optical axis direction of the lens, a magnet that is fixed to the lens holding frame, and the actuator And a magnet detection member that is fixed to the housing and detects the position of the magnet in the lens holding frame movement direction, the magnet detection member as seen from the lens holding frame movement direction. It arrange | positions so that it may overlap with a part or whole of a magnet, It is characterized by the above-mentioned.

  According to this, since the magnet detection member is disposed at a position overlapping the magnet as viewed from the lens holding frame moving direction, the area occupied by the magnet and the magnet detecting member as viewed from the lens holding frame moving direction can be reduced. Thereby, the diameter of the lens can be increased without increasing the installation area of the entire apparatus, and the entire apparatus can be made compact.

  Further, for example, the wiring to the processing circuit disposed on the image side of the lens can be shortened, it is difficult to receive noise, the lens position detection accuracy and controllability are improved, and high-speed and high-precision autofocus is possible.

  According to another aspect, in the lens driving device described above, the housing is provided alongside the lens storage unit that movably stores the lens holding frame and the lens storage unit along the optical axis direction. An image sensor housing portion for housing the image sensor, a plate-like portion formed between the lens housing portion and the image sensor housing portion in the optical axis direction, and a metal insert-molded in the plate-like portion Wiring member, the plate-like portion includes a magnet detection member holding portion holding the magnet detection member, and the wiring member is electrically connected to the magnet detection member held by the magnet detection member holding portion. It is arrange | positioned at the said magnet detection member holding | maintenance part so that connection is possible. The plate-like portion is formed with a through-hole for guiding the light from the lens to the image sensor at the center portion, and the wiring member is disposed exposed to the magnet detection member holding portion. It is preferable.

  According to this, since the magnet detection member is directly held by the magnet detection member holding portion of the housing, the positional accuracy of the Hall element is further improved, and the accuracy is maintained over a long period of time. Moreover, the magnet detection member and the wiring member can be easily electrically connected, and the assembly of the magnet detection member to the housing can be further facilitated.

  According to another aspect, in the lens driving device described above, the housing includes a lens storage unit that stores the lens holding frame, and an imaging device that is provided alongside the lens storage unit along the optical axis direction. An image sensor housing portion for housing a wire, a plate-like portion formed between the lens housing portion and the image sensor housing portion in the optical axis direction, and a wiring having a wiring pattern and cut out from a copper-clad laminate A board, wherein the plate-like part includes a magnet detection member holding part holding the magnet detection member, and the wiring board is a cut surface cut from the copper-clad laminate, and the imaging element storage part And the lens storage portion are covered with a covering member, and the wiring pattern is electrically connected to the magnet detection member held by the magnet detection member holding portion. Possible magnet detection member Characterized in that it is arranged in the lifting unit. The plate-like portion is formed with a through-hole for guiding light from the lens to the imaging element at a central portion, and the wiring board is a cut surface cut from the copper-clad laminate, and A cutting surface disposed in one or both of the imaging element storage unit and the lens storage unit is covered with a covering member, and a part or all of the cutting surface is covered with a covering member, and the covering A part or all of the cut surface is disposed in one to three of the imaging element storage unit, the lens storage unit, and the through hole, and the wiring pattern is held by the magnet detection member holding unit. It is preferable that the magnet detection member is disposed so as to be electrically connected to the magnet detection member.

  According to this, a magnet detection member and a wiring board can be electrically connected easily, and the assembly | attachment to the housing | casing of a magnet detection member can be made still easier.

  Moreover, the wiring board cut and formed from the copper-clad laminate is likely to generate dust from the cut surface, and when this dust adheres to the image sensor, the shadow is recorded by the image sensor. Since the cut surface disposed in one or both of the storage unit and the lens storage unit is covered with the covering member, dust is generated from the cut surface without being exposed to the image sensor storage unit or the lens storage unit. It can be made with less fear.

  According to another aspect, in the lens driving device described above, the magnet detection member holding portion is formed so as to receive the magnet detection member from the optical axis direction.

  According to this, it becomes easy to mechanically dispose the magnet detection member to the magnet detection member holding portion, and the assembly workability of the magnet detection member is further facilitated, and automation is also possible. Can be mass-produced.

  An imaging apparatus according to the present invention includes the lens driving device according to any one of the above, an imaging device that is attached to the housing and converts an optical image into an electrical signal, and one or more lenses. An imaging optical system that forms an optical image on a light receiving surface of the imaging device, and a lens that moves along an optical axis direction among one or a plurality of lenses in the imaging optical system is a lens driving device. It is attached to the lens holding frame.

  According to this, the occupation area of the magnet and the magnet detection member as seen from the optical axis direction can be reduced, whereby the diameter of the lens can be easily increased, and the entire apparatus can be made compact.

  In addition, since the magnet detection member is attached to the lens holding frame, the wiring to the processing circuit disposed on the image side of the lens can be shortened, it is difficult to receive noise, and the lens position detection accuracy and controllability are improved. High-speed and high-precision autofocus is possible. In addition, the positioning accuracy and reliability of the magnet detection member are improved, and the imaging apparatus can maintain the autofocus accuracy over a long period of time.

  An imaging apparatus according to the present invention includes any of the lens driving devices described above, an imaging optical system that includes one or more lenses and forms an optical image of an object, and imaging that converts the optical image into an electrical signal. A lens that moves along the optical axis direction of one or a plurality of lenses in the imaging optical system is attached to a lens holding frame of the lens driving device. The circuit board is attached to the housing, and the magnet detection member is attached on the circuit board.

  According to this, the occupation area of the magnet and the magnet detection member as seen from the optical axis direction can be reduced, whereby the diameter of the lens can be easily increased, and the entire apparatus can be made compact.

  In addition, since the magnet detection member is attached to the lens holding frame, the wiring to the processing circuit disposed on the image side of the lens can be shortened, it is difficult to receive noise, and the lens position detection accuracy and controllability are improved. High-speed and high-precision autofocus is possible. In addition, the positioning accuracy and reliability of the magnet detection member are improved, and the imaging apparatus can maintain the autofocus accuracy over a long period of time.

  The lens driving device and the imaging device of the present invention can reduce the size of the entire device, can easily increase the diameter of the lens, can improve the lens position detection characteristics, and can be easily assembled with a magnet position detection member.

It is a disassembled perspective view which abbreviate | omitted the cover of the imaging device of 1st Embodiment of this invention. It is the top view which abbreviate | omitted the cover of the imaging device of FIG. It is sectional drawing of the principal part of the imaging device of FIG. It is a bottom view of the modification of the imaging device of 1st Embodiment. It is sectional drawing of the principal part of the modification of FIG. It is the top view which abbreviate | omitted the cover of the imaging device of 2nd Embodiment. It is sectional drawing of the principal part of FIG. It is the top view which omitted the cover of the imaging device of a 3rd embodiment. It is sectional drawing of the principal part of FIG.

  Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. 1 is an exploded perspective view in which the cover of the image pickup apparatus according to the first embodiment of the present invention is omitted, FIG. 2 is a plan view of the image pickup apparatus in FIG. 1, and FIG. 3 is a cross-sectional view of the main part of the image pickup apparatus in FIG. FIG. 1, 3, 5, 7, and 9, the X direction is the vertical direction (optical axis direction), the −X direction is the upper side (object side), and the + X direction is the lower side (image side). Will be described.

  The imaging apparatus 100 of this embodiment includes a lens driving device 10 and an imaging element 9. As shown in FIG. 1, the lens driving device 10 includes a housing 1, an actuator 3 held by the housing 1, a lens holding frame 4, a lens position detection mechanism unit 8, and a cover 7 (shown in FIG. 3). ).

  The housing 1 is made of a resin material such as LCP (liquid crystal polymer), and is formed by injection molding or the like. The housing 1 of this embodiment includes a housing body 2 and support columns 20a to 20d. The casing main body 2 has a rectangular shape having four corners of the first corner 4a to the fourth corner 2d in a plan view as viewed from the optical axis direction, and a circle serving as an optical path at the center. It consists of a plate-like body having a through-hole 21 having a shape.

  Further, the housing body 2 includes an image sensor housing portion 24 for housing the image sensor 9 on the lower surface. The image sensor housing portion 24 is formed to be recessed in a rectangular shape with a predetermined depth upward from the lower surface. With this image sensor housing portion 24, the housing main body portion 2 captures an image between the lens housing portion 25 and the imaging device housing portion 24 between a lens housing portion 25 and an image sensor housing portion 24, which will be described later, formed above the housing body portion 2. A plate-like portion 26 interposed so as to partition the element storage portion 24 is provided.

  Further, the plate-like portion 26 is provided with a hall element 82 of the lens position detecting mechanism portion 8 to be described later on the upper surface of the second corner portion 2b formed adjacent to the first corner portion 2a in the clockwise direction in FIG. A hall element holding part (magnet detection member holding part) 23 for holding is provided. The hall element holding part 23 is formed to be recessed from the upper surface of the housing body part 2 in a square shape at a predetermined depth in plan view.

  In this embodiment, the hall element holding portion 23 includes first holding pieces 23 a to fourth holding pieces 23 d that protrude inward from each of the four inner side surfaces, and these first holding pieces 23 a to fourth. A fitting portion 23e into which the hall element 82 is fitted is defined on the inner side of the holding piece 23d.

  Specifically, the first holding piece 23a and the third holding piece 23c facing the first holding piece 23a are formed at a distance similar to the width of the Hall element 82, and the second holding piece 23b and the fourth holding piece facing the second holding piece 23b. The piece 23d is formed at a distance similar to the length of the Hall element 82. As a result, the Hall element 82 is fitted into the fitting portion 23e, and the Hall element 82 after being fitted is held by the first holding piece 23a to the fourth holding piece 23d with a slight gap. It has become. The size of the gap is approximately 0.05 to 0.15 mm, with a gap that is not press-fitted in consideration of the package dimension tolerance of the Hall element 82 and the molding dimension tolerance of the housing 1.

  Further, a metal wiring member 27 that electrically connects a Hall element 82 and a circuit board 91 that holds an imaging element 9 described later is insert-molded in the plate-like portion 26. Specifically, the wiring member 27 is made of, for example, a copper alloy used for a lead frame of a semiconductor package, and one end of the wiring member 27 is below the Hall element 82 held by the Hall element holding portion 23. Thus, the other end of the wiring member 27 is arranged so as to extend from the hall element holding part 23 to the outside of the housing main body part 2. .

  Further, as shown in FIG. 1, an actuator holding portion 22 holding the actuator 3 is provided at the first corner portion 2 a on the upper surface of the plate-like portion 26. The actuator holding part 22 is formed in a circular shape with a predetermined depth from the upper surface of the housing body part 2.

  The support pillars 20a to 20d are formed so as to protrude upward from the upper surface of the housing body 2 at positions corresponding to the first corner 2a to the fourth corner 2d of the housing 2. It is comprised from four of the support pillar 20a-the 4th support pillar 20d.

  Specifically, the first support column 20a is formed at the first corner 2a, and the second support column 20b is formed at the second corner 2b. The third support column 20a is formed in a third corner 2c disposed diagonally to the first corner 2a, and the fourth support column 20a is adjacent to the third corner 2c. However, it is formed at the fourth corner 2d arranged in the clockwise direction in FIG.

  And the lens storage part 25 which accommodates the lens holding frame 4 is formed in the upper side of the housing body 2 by the first support pillar 20a to the fourth support pillar 20d.

  The third support pillar 20c is formed with a restricting portion receiving groove 29 for receiving a rotation restricting stopper 52 of the lens holding frame 4 to be described later so as to be movable in the vertical direction. Then, on both inner side surfaces of the restricting portion receiving groove 29, when the lens holding frame 4 rotates around an axis of a drive shaft 32 of the actuator 3 described later, a rotation restricting stopper 52 of the lens holding frame 4 is provided. Is provided with a rotation restricting stopper 29a for restricting the rotation and restricting the rotation.

  As shown in FIG. 1, the actuator 3 includes a piezoelectric element 31 that is an electromechanical conversion element that expands and contracts in the axial direction, a drive shaft 32 that is joined to one end of the piezoelectric element 31, and a joint that is joined to the other end of the piezoelectric element 31. A weight 33 is provided.

  The weight 33 is for generating more displacement due to expansion and contraction of the piezoelectric element 31 on the drive shaft 32 side. In this embodiment, the weight 33 is made of a material having a high specific gravity such as tungsten or a tungsten alloy.

  Further, the weight 33 is formed of a columnar shape whose outer diameter protrudes from the outer periphery of the piezoelectric element 31 over the entire periphery in the outer peripheral direction.

  The piezoelectric element 31 converts input electric energy into a mechanical expansion / contraction motion by a piezoelectric effect. Such a piezoelectric element includes, for example, a laminated body and a pair of external electrodes.

  The laminated body is formed by alternately laminating a plurality of thin film (layered) piezoelectric layers made of a piezoelectric material and a conductive thin film (layered) internal electrode layer. In the present embodiment, the laminate has a quadrangular prism shape, but is not limited to this, and may be, for example, a polygonal column shape or a cylindrical shape.

Examples of the piezoelectric material include lead zirconate titanate (so-called PZT), crystal, lithium niobate (LiNbO ₃ ), potassium tantalate niobate (K (Ta, Nb) O ₃ ), barium titanate (BaTiO ₃ ), Inorganic piezoelectric materials such as lithium tantalate (LiTaO ₃ ) and strontium titanate (SrTiO ₃ ).

  Each of the plurality of internal electrode layers is configured to face the outside on a pair of outer peripheral side surfaces that are alternately opposed to each other in order.

  In addition, the pair of external electrodes is connected to the pair of side surfaces facing each other such that the first external electrode and the second external electrode are connected to each other in parallel to supply the electrical energy to the laminate. It is formed by sputtering.

  The lower end surface of the piezoelectric element 31 is bonded to the upper end surface of the weight 33 with an adhesive such as an epoxy adhesive.

  The drive shaft 32 is formed into a cylindrical shape with resin so that carbon fibers are arranged in the axial direction. The drive shaft 32 of this embodiment is formed so that the outer diameter protrudes from the outer periphery of the piezoelectric element 31 to the outer periphery over the entire periphery.

  The lower end surface of the drive shaft 32 is bonded to the upper end surface (one end) of the piezoelectric element 31 with an adhesive such as an epoxy adhesive. As this adhesive, the same adhesive as the adhesive that bonds the piezoelectric element 31 and the weight 33 can be used.

  In this embodiment, although not shown, the adhesive is an adhesive (fillet) that protrudes from the joint surface between the drive shaft 32 and the piezoelectric element 31 and is formed on the piezoelectric element side. The entire region can be used for sliding with the lens holding frame 4, and a large stroke can be realized with the short drive shaft 32.

  The actuator 3 is attached to the actuator holding portion 22 of the housing 1 from the weight 33 side, and the bottom surface and inner peripheral wall of the actuator holding portion 22 and the weight 33 are bonded by an adhesive (not shown). It is fixed.

  The weight 33 is omitted when the lower end surface of the piezoelectric element 31 can be mounted and held directly on the housing 1 to exhibit the same function as the weight 33. Also good.

  Next, the lens holding frame 4 will be described. As shown in FIGS. 1 and 2, the lens holding frame 4 according to this embodiment has a substantially cylindrical lens holding frame main body 5 made of a resin material such as LCP (liquid crystal polymer) and a predetermined friction against the drive shaft 32. The engaging member 6 is slidably engaged by force.

  The lens holding frame main body 5 includes a lens holding portion 54 on the inner peripheral side, and one or a plurality of lenses 55 are held in the lens holding portion 54.

  The lens holding frame main body 5 has an engagement member holding portion 51 for holding the engaging member 6 on the outer periphery, and a rotation restricting cover for restricting the rotation of the lens holding frame 4 with respect to the drive shaft 32. The stop part 52 is provided.

  The engaging member holding part 51 is formed over substantially the outer circumference of the lens holding frame main body part 5. Further, the engaging member holding part 51 is provided with a drive bearing holding part 51b for holding an engaging member 6 described later on one end side thereof.

  The rotation restricting stopper 52 is formed in the lens holding frame main body 5 at a position approximately 180 ° away from the drive bearing holder 51 b in the circumferential direction.

  The rotation restricting stopper 52 of this embodiment includes a restricting main body 52a and a hemispherical protrusion 52b formed on the restricting main body 52a.

  The restriction main body 52 a is projected in a quadrangular prism shape from the outer periphery of the engaging member holding portion 51 to the radially outer side. Further, the protrusion 52b protrudes outward from both outer side surfaces of the restriction main body 52a. The outer width of the protrusions 52b is set to be slightly narrower than the inner width of the restricting portion receiving groove 29 of the housing 1, that is, the distance between the rotation restricting stopping portions 29a.

  The engaging member 6 includes an engaging member main body 61 having metal elasticity and a belt-like elastic body 62 having metal elasticity. In this embodiment, the engaging member main body 61 is formed of a belt-like shape, and includes a drive bearing portion 63 on one end side in the longitudinal direction.

  The drive shaft receiving portion 63 includes a first receiving portion 63a and a second receiving portion 63b that is bent at a substantially right angle from the first receiving portion 63a, and thereby receives the drive shaft 32 slidably.

  The elastic body 62 includes a pressing portion 62 a that presses the drive shaft 32 against the drive bearing portion 63 on one end side in the longitudinal direction. In this embodiment, the pressing portion 62 a is formed such that the vertical width is smaller than the width of the drive bearing portion 63.

  The elastic body 62 is arranged on one side in the thickness direction of the engaging member main body 61 such that the pressing portion 62a faces the drive bearing portion 63, and in this state, the elastic body 62 extends in the longitudinal direction. The other end side is fixedly connected to the engaging member main body 61.

  The engaging member 6 configured in this manner is arranged so that the other surface side in the thickness direction of the engaging member main body 61 faces the engaging member holding portion 51 of the lens holding frame main body portion 5. The engaging member main body 61 and the engaging member holding part 51 are bonded together by an adhesive interposed therebetween.

  Then, the drive shaft 32 is received between the pressing portion 62 a of the engagement member 6 connected to the lens holding frame main body portion 5 and the drive bearing portion 63, and the engagement member 6 can slide in the axial direction with the drive shaft 32. Are frictionally engaged. In this state, the lens holding frame 4 is housed in the lens housing portion 25 of the housing 1 so as to be movable in the optical axis direction, and the Hall element holding portion 23 of the housing 1 is below the lens 55 (image side). Is located.

  The lens position detection mechanism unit 8 detects the position of the lens holding frame 4 in the optical axis direction with respect to the housing 1. The lens position detection mechanism unit of this embodiment includes a magnet 81 and a magnetic flux accompanying the movement of the magnet 81. It comprises a Hall element (magnet detection member) 82 which is a magnetic flux density detection means for detecting the position of the magnet 81 by detecting a density change.

  The magnet 81 is attached at a position between the drive bearing holding portion 51 b and the rotation restricting stopper 52 on the outer periphery of the lens holding frame main body 5, and the engaging member 6 of the lens holding frame 4. Is disposed above the hall element holding portion 23 in the housing 1 in a state of being frictionally engaged with the drive shaft 32.

  In this embodiment, the Hall element 82 is composed of a GaAs Hall element. In this embodiment, the Hall element 82 is held in the Hall element holding portion 23 as follows.

  The hall element 82 is inserted into the hall element holding portion 23 by being mounted from above by a mounter or the like, is electrically connected to one end of the wiring member 27 by solder, and is connected to the circuit board via the wiring member 27 and the solder bridge 27a. 91 is electrically connected. The connection between the hall element 82 and the wiring member 27 is not limited to solder, and a conductive adhesive or the like may be used. In that case, it is preferable to use a reinforcing adhesive. When the connection is made with solder or a thermosetting conductive adhesive, the resin used for molding is preferably a resin having excellent heat deformation temperature such as a liquid crystal polymer from the viewpoint of heat resistance.

  Thus, the Hall element 82 can be mechanically assembled by a mounter or the like by being inserted into the Hall element holding portion 23 from the upper side (optical axis direction side).

  The cover 7 is made of metal sheet metal, and includes a cover optical path through hole 71 serving as an optical path at the center as shown in FIG. And the cover 7 is arrange | positioned so that the outer peripheral side of the 1st support pillar 20a-the 4th support pillar 20d may be covered from the upper side of the 1st support pillar 20a-the 4th support pillar 20d, and the 1st support pillar 20a-the 2nd. The upper surface of the cover 7 is bonded and bonded to the upper surface of each of the four support columns 20d with an adhesive in a state where the inner surface of the upper wall of the cover 7 is placed. Then, the cover 7 covers and hides the lens storage portion 25 of the housing 1.

  The image sensor 9 is an image of each component of R (red), G (green), and B (blue) according to the amount of light in an optical image of an object (subject) imaged by an imaging optical system (not shown) as a whole. It is an element that photoelectrically converts a signal and outputs it to a predetermined image processing circuit (not shown). The imaging element 9 is, for example, a CCD type image sensor, a CMOS type image sensor, or the like.

  The imaging optical system includes one or more lenses 55 and forms an optical image of an object on the light receiving surface of the imaging device 9. The lens 55 is a lens that moves along the optical axis of the one or more lenses in such an imaging optical system. The lens 55 may be a single lens or may include a plurality of lenses. The lens 55 may be, for example, a lens that moves along the optical axis to perform focusing (focusing), or a lens that moves along the optical axis to perform zooming (magnification), for example. It may be. An optical image of the object is guided by the imaging optical system including the lens 55 to the light receiving surface of the imaging device 9 along the optical axis thereof, and the optical image of the object is captured by the imaging device 9. .

  The image sensor 9 is held on the circuit board 91. As shown in FIG. 3, the circuit board 91 is held on the lower surface of the housing 1 and is electrically connected to the other end of the wiring member 27. In this state, the image sensor 9 is housed in the image sensor housing section 24 and converts the subject image formed by the lens 55 into an electrical signal. The converted electrical signal passes through the circuit board 91 and is not transmitted. The image is transmitted to the illustrated external processing circuit and recorded as an image, for example.

  The imaging device 100 configured as described above is used by being mounted on, for example, a mobile phone. When power is supplied to the piezoelectric element 31 from a drive circuit provided in the mobile phone, an autofocus operation is performed.

  Specifically, when a sawtooth voltage is applied to the piezoelectric element 31 of the actuator 3 from the drive circuit, the piezoelectric element 31 is gently extended and displaced in the optical axis direction (Z direction) at the gently rising portion of the sawtooth waveform. The drive shaft 32 is also gradually displaced in the same direction. At this time, the lens holding frame 4 frictionally coupled to the drive shaft 32 is displaced together with the drive shaft 32.

  At the rapidly falling portion of the sawtooth waveform, the piezoelectric element 31 is rapidly contracted and displaced in the optical axis direction, and the drive shaft 32 is also rapidly displaced in the same direction. At this time, the lens holding frame 4 frictionally coupled to the drive shaft 32 overcomes the frictional coupling force by the inertial force, slips between the drive shaft 32, stays at that position, and does not substantially move. By repeating this, the lens holding frame 4 continuously moves in the optical axis direction along the drive shaft 32.

  Further, when the lens holding frame 4 moves in the axial direction of the drive shaft 32, the Hall element 82 provided in the housing 1 detects a change in magnetic flux density due to the movement of the magnet 81 provided in the lens holding frame 4. Then, the position of the lens holding frame 4 with respect to the housing 1 in the optical axis direction is detected. Thereby, the autofocus operation is performed while controlling the position of the lens in the optical axis direction.

  At this time, since the Hall element 82 is disposed on the lower side, which is the image side of the lens, the wiring to the circuit board 91 is shortened and is less susceptible to noise, and the lens position detection accuracy and controllability are reduced. Is improved, and high-speed and high-precision autofocus is possible.

  Since the imaging device 100 configured as described above has a configuration in which the magnet 81 and the Hall element 82 overlap (overlap) when viewed from the optical axis direction, the arrangement efficiency in a plane orthogonal to the optical axis. The lens has a large diameter, and the diameter of the lens can be increased.

  Further, it is not necessary to use another member such as an FPC as the wiring member of the Hall element 82, and the Hall element 82 is not positioned and held via the FPC as in the case of using the FPC, and more directly. It is fixed to the housing 1, thereby improving the positional accuracy of the Hall element 82 and maintaining the accuracy over a long period of time.

  Further, the Hall element 82 can be incorporated into the housing 1 from the optical axis direction, and it is not necessary to rotate the whole during the assembling work, and the assembling workability is also good. In addition, since a member that is difficult to handle with an automatic machine such as an FPC or a lead wire is not used, it is suitable for assembly automation. Further, if insert molding is performed with a hoop, the Hall element 82 is installed by a mounter, and reflow soldering is performed, these operations can be almost completely automated.

  In the first embodiment, the Hall element holding portion 23 is formed to be recessed from the upper surface of the plate-like portion 26 in the housing body 2, that is, from the lens storage portion 25 side at a predetermined depth. However, it is not limited to this form, and can be changed as appropriate.

  For example, as shown in FIGS. 4 and 5, the housing body 2 may be formed to be recessed from the lower surface of the plate-like portion 26, that is, from the image sensor housing portion 24 side at a predetermined depth.

  In the first embodiment, the wiring member 27 is formed only for connection to the Hall element 82. However, the wiring member 27 is not limited to this configuration, and can be changed as appropriate. For example, the power supply line of the actuator 3 can be formed by insert molding. It may be formed. Further, other circuits such as an amplifier for output of the Hall element 82, a driver IC for the actuator 3, and a feedback control IC in which these are integrated may be mounted. Thereby, improvement in noise sensitivity of the position detection of the lens holding frame and generation of noise from the actuator drive line can be suppressed.

  Next, the imaging apparatus 200 according to the second embodiment will be described. As shown in FIGS. 6 and 7, in the imaging device 200 according to the second embodiment, the Hall element holding portion 223 of the plate-like portion 226 in the case main body 202 of the case 201 is arranged from the upper surface to the lower surface of the plate-like portion 226. It is formed so as to penetrate through.

  The housing body 202 of the housing 201 includes a wiring board 227 fixedly attached to the plate-like portion 226. The wiring board 227 is cut out from a glass epoxy board (copper-clad laminate) and formed into a small glass epoxy board piece (small copper-clad laminate board) having a predetermined size. A wiring pattern 228 for electrically connecting to the element 82 is formed.

  The wiring board 227 is attached to the lower surface side of the plate-like part 226 so as to close the lower side of the hall element holding part 223 and is disposed in the image sensor housing part 24. 228 is exposed in the Hall element holding portion 23.

  Further, the wiring board 227 of this embodiment has a cut surface 227a disposed in the image sensor housing portion 24 among the cut surfaces cut from the glass epoxy substrate (copper-clad laminate), and a covering member made of a synthetic resin. 227b.

  The cut surface 227a cut from the glass epoxy substrate is likely to generate dust, and when the dust adheres to the image sensor, the shadow is recorded by the image sensor. Therefore, in the second embodiment, the cut surface 227a is covered with the covering member 227b so as not to be exposed to the image sensor housing portion 24.

  The hall element 82 is fitted into the hall element holding part 23 from the lens housing part 25 side and mounted on the wiring pattern 228 of the wiring board 227. Thereby, the Hall element 82 is electrically connected to the circuit board 91 via the wiring pattern 228 of the wiring board 227 and the solder bridge 227c.

  Also in the imaging apparatus 200 of the second embodiment configured as described above, the magnet 81 and the Hall element 82 are arranged so as to overlap each other when viewed from the optical axis direction, and therefore, in a plane orthogonal to the optical axis. Arrangement efficiency is high, and the diameter of the lens can be increased.

  The Hall element 82 is more directly fixed to the housing 201, thereby improving the positional accuracy of the Hall element 82 and maintaining the accuracy over a long period of time.

  Further, the Hall element 82 can be incorporated into the housing 201 from the optical axis direction, and it is not necessary to rotate the whole during the assembling work, and the assembling workability is also good. In addition, since a member that is difficult to handle with an automatic machine such as an FPC or a lead wire is not used, it is suitable for assembly automation. Further, insert molding is performed in a state where a plurality of small glass epoxy substrate pieces (small copper-clad laminate pieces) are connected to the glass epoxy substrate (copper-clad laminate) outside the image sensor housing portion 24, and a Hall element 82 by a mounter is used. After performing the installation and reflow soldering, if the portion where the small glass epoxy board piece (small copper clad laminate piece) is connected outside the image pickup device storage section 24 is cut, these operations can be almost completely automated.

  In the second embodiment, the wiring board 227 is attached to the lower surface side of the plate-like part 226 so as to close the lower side of the hall element holding part 223 and is disposed in the imaging element storage part 24. Not only the form but also can be changed as appropriate.

  For example, the wiring board 227 is attached to the upper surface side of the plate-like part 226 so as to block the upper side of the hall element holding part 223, and the wiring pattern 228 of the wiring board 227 is exposed in the hall element holding part 23 in the lens housing part 25. The hall element 82 may be fitted into the hall element holding part 223 from the image sensor housing part 24 side.

  In this case, since the cut surface of the wiring board 227 is disposed in the lens housing portion 25, the cut surface disposed in the lens housing portion 25 should be covered with a covering member. preferable.

  Also, in the second embodiment, it is used only for connection to the Hall element 82. However, for example, the power supply line of the actuator 3 is formed by a wiring pattern on the wiring board 227, and other circuits, for example, the Hall element 82 are used. An output amplifier, a driver IC for the actuator 3, a feedback control IC in which these are integrated may be mounted. Thereby, improvement in noise sensitivity of the position detection of the lens holding frame and generation of noise from the actuator drive line can be suppressed.

  Next, an imaging apparatus 300 according to the third embodiment will be described. As shown in FIGS. 8 and 9, in the imaging apparatus 300 of the third embodiment, the Hall element 82 is fixedly mounted in advance on the circuit board 391 together with the imaging element and peripheral circuit components.

  Also in the imaging apparatus 300 of the third embodiment configured as described above, the magnet 81 and the Hall element 82 are arranged so as to overlap each other when viewed from the optical axis direction, and therefore, in a plane orthogonal to the optical axis. Arrangement efficiency is high, and the diameter of the lens can be increased.

  Further, the Hall element 82 can be mounted on the circuit board 391 together with the image pickup element 9 and peripheral circuit components by a mounter and reflow solder, and it is not necessary to use another member such as an FPC as a wiring member for the Hall element. The Hall element assembly can be completed within the process of incorporating the existing image sensor 9 into the circuit board 391. The Hall element 82 is held by the housing 301 via the circuit board. However, when the circuit board 391 is assembled, the position of the circuit board 391 is precisely adjusted by the image pickup element image, and the fixing means is also the image pickup element. Therefore, position accuracy and reliability equivalent to those of the image sensor 9 can be obtained without requiring an additional special process.

  Further, if the Hall element 82 and the Hall element amplifier (or a feedback control IC incorporating the Hall element 82) are arranged on the circuit board 391 in the immediate vicinity, noise sensitivity to position detection can be minimized.

  In the first to third embodiments, the Hall element 82 is disposed so as to overlap with a part of the magnet 81 when viewed from the optical axis direction. For example, the Hall element 82 may be disposed so as to overlap the entire magnet 81 when viewed from the optical axis direction, and can be changed as appropriate.

1, 201, 301 Housing 2 Housing body 3 Actuator 4 Lens holding frame 5 Lens holding frame body 6 Engaging member 9 Imaging element 10 Lens driving device 23 Hall element holding part 81 Magnet 82 Hall element (magnet position detecting member)
91, 391 Circuit board 100, 200, 300 Imaging device

Claims (6)

A lens holding frame holding one or more lenses;
An actuator for moving the lens holding frame in the direction of the optical axis of the lens;
A magnet fixed to the lens holding frame;
A housing holding the actuator;
A magnet detection member fixed to the casing for detecting the position of the magnet in the lens holding frame movement direction;
The lens driving device, wherein the magnet detection member is disposed so as to overlap a part or the whole of the magnet as viewed from the moving direction of the lens holding frame. The housing includes a lens housing portion that movably houses the lens holding frame;
An image sensor housing section that is provided alongside the lens housing section along the optical axis direction and houses an image sensor;
A plate-like portion formed between the lens housing portion and the image sensor housing portion in the optical axis direction, and a metal wiring member insert-molded in the plate-like portion,
The plate-like portion includes a magnet detection member holding portion that holds the magnet detection member,
The lens drive according to claim 1, wherein the wiring member is disposed in the magnet detection member holding portion so as to be electrically connectable to the magnet detection member held in the magnet detection member holding portion. apparatus. The housing includes a lens storage unit that stores the lens holding frame;
An image sensor housing portion that is provided alongside the lens housing portion along the optical axis direction and houses an image sensor, and a plate formed between the lens housing portion and the image sensor housing portion in the optical axis direction And a wiring board having a wiring pattern and cut out from a copper-clad laminate,
The plate-like portion includes a magnet detection member holding portion that holds the magnet detection member,
The wiring board is a cut surface cut from the copper clad laminate, and a cut surface disposed on one or both of the imaging element storage portion and the lens storage portion is covered with a covering member,
The lens drive according to claim 1, wherein the wiring pattern is disposed in the magnet detection member holding portion so as to be electrically connectable to the magnet detection member held in the magnet detection member holding portion. apparatus.   The lens driving device according to claim 2, wherein the magnet detection member holding portion is formed so as to be able to receive the magnet detection member from the optical axis direction. The lens driving device according to any one of claims 1 to 4,
An image sensor that is mounted on the housing and converts an optical image into an electrical signal;
An imaging optical system that includes one or a plurality of lenses, and that forms an optical image of an object on a light receiving surface of the imaging device;
An imaging apparatus, wherein a lens that moves in the optical axis direction among one or a plurality of lenses in the imaging optical system is attached to a lens holding frame of the lens driving apparatus. The lens driving device according to any one of claims 1 to 4,
An imaging optical system that includes one or more lenses and forms an optical image of the object;
An image sensor for converting the optical image into an electrical signal;
A circuit board coupled to the imaging device,
The lens that moves along the optical axis direction among one or a plurality of lenses in the imaging optical system is attached to a lens holding frame of the lens driving device,
The circuit board is attached to the housing,
The image pickup apparatus, wherein the magnet detection member is mounted on the circuit board.

Images