JP2014062975A - Leaf spring for camera module drive mechanism and manufacturing method for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a leaf spring for a camera module drive mechanism, which enables use of solder with better wettability.SOLUTION: A method of manufacturing a leaf spring with electrical connection terminals for a camera module drive mechanism includes the steps of: preparing a leaf spring material 40; etching and half-etching the leaf spring material 40 using resist 41; and removing the resist 41 from the leaf spring material 40. An external shape of the leaf spring material 40 is formed through the etching process and connection terminals 11d, 11e are formed through the half-etching process.

Description

  The present invention relates to a leaf spring for a driving mechanism of a camera module and a method for manufacturing the same, and more particularly to a leaf spring for a driving mechanism for a camera module capable of improving solder wettability and a method for manufacturing the same.

  In a camera-equipped mobile phone or the like, the lens unit can be displaced in the direction of the optical axis by the interaction between the current flowing through the coil and the magnetic field of the magnetic circuit composed of the yoke and magnet for the purpose of autofocus and zooming. A known camera module drive mechanism (voice coil motor) is known.

  In such a camera module drive mechanism, a leaf spring is used for supporting the holder holding the lens unit in the housing so as to be displaceable in the optical axis direction.

  This leaf spring is obtained by preparing a leaf spring material, etching the leaf spring material using a resist, and then peeling off the resist on the surface of the leaf spring material.

  By the way, a leaf | plate spring is connected with a coil and an electric current is sent from the leaf | plate spring to the coil side. In this case, since the leaf spring and the coil are joined by solder, a leaf spring that can improve solder wettability is required.

  In other words, the leaf spring and the coil are bonded using cream solder containing flux, but in consideration of mass production, the flux contains low flux activity so that the flux does not decompose and accumulate dirt on the lens etc. Cream solder is used. However, cream solder containing a flux with low activity may be inferior in solder wettability.

  In addition to this, it has been found that a phenomenon called “concentration” occurs in which trace elements that inhibit solder wettability aggregate on the surface of the leaf spring material.

JP2009-122360A

  The present invention has been made in view of such points, and provides a leaf spring for a driving mechanism of a camera module and a method for manufacturing the same that can improve solder wettability while suppressing contamination on a lens or the like. With the goal.

  The present invention relates to a method of manufacturing a leaf spring for a driving mechanism of a camera module including an electrical connection terminal, a step of preparing a leaf spring material made of a Cu-based alloy, and an outer shape process by etching the leaf spring material using a resist. And a plate spring for a drive mechanism of a camera module, comprising: a step of half-etching to form an electrical connection terminal; and a step of peeling the resist from the plate spring material after etching and half-etching It is a manufacturing method.

  The present invention is a method for manufacturing a leaf spring for a drive mechanism of a camera module, comprising preparing a leaf spring material made of a copper alloy containing at least one of Be, Ni, Cr, Si, Ti, and Sn. .

  The present invention is a leaf spring for a drive mechanism of a camera module including an electrical connection terminal obtained by the method for manufacturing a leaf spring for a drive mechanism of a camera module described above.

  According to the present invention, it is possible to remove trace elements that hinder solder wettability by half-etching a leaf spring material made of a Cu-based alloy, thereby improving adhesion with solder. Moreover, since the surface area of the electrical connection terminal is increased by half-etching, it is possible to improve the adhesion to the solder.

  In particular, when the leaf spring material is made of a copper alloy containing at least one of Be, Ni, Cr, Si, Ti, and Sn, a connection terminal for a concentration area of trace elements that hinder solder wettability remaining on the surface of the leaf spring material It can be removed from the surface, which can improve solder wettability.

FIG. 1 is an exploded perspective view showing a drive mechanism of a camera module. FIG. 2 is a plan view showing an upper leaf spring incorporated in a camera module drive mechanism. FIG. 3 is a plan view showing a lower leaf spring incorporated in the drive mechanism of the camera module. FIG. 4 is a schematic side view showing the camera module. FIGS. 5A to 5D are views showing a method for manufacturing an upper leaf spring and a lower leaf spring.

  Embodiments of the present invention will be described below with reference to the drawings.

  As shown in FIGS. 1 to 4, the camera module drive mechanism 1 according to the present invention includes a housing 2A composed of a cover 2 and a base 13, a lens unit 26A composed of a plurality of lenses 26 constituting an optical system, A holder 9 which is disposed in the housing 2A and accommodates the lens unit 26A and is movable in the optical axis direction of the lens unit 26A, a coil 8 provided on the outer periphery of the holder 9, and a base 13 of the housing 2A. A yoke 6 and a magnet piece 7 for providing a magnetic field to the coil 8 are provided.

  An upper leaf spring 5 is interposed between the cover 2 of the housing 2A and the upper portion of the yoke 6, and a lower leaf spring 11 is interposed between the base 13 of the housing 2A and the lower portion of the yoke 6. Yes. In this case, an adjustment plate 4 for adjusting the thickness of the upper leaf spring 5 is provided between the upper leaf spring 5 and the cover 2.

  The lower leaf spring 11 and the coil 8 are soldered via a connection terminal 11d described later.

  Then, when an electric current is passed through the coil 8 via the lower leaf spring 11, an upward force acts on the holder 9, and the lens unit 26A moves upward as a whole against the forces of the upper leaf spring 5 and the lower leaf spring 11. Can be lifted (see FIG. 4).

  Also, by adjusting the amount of current to be input, the force that moves the holder 9 upward is changed, and the balance between the force of the upper leaf spring 5 and the lower leaf spring 11 allows the holder 9 to move up and down. Position adjustment can be performed.

  As shown in FIG. 4, the housing 2 </ b> A is fixed above the base body 20 via the intermediate support body 21, supported by the infrared support glass 22 on the intermediate support body 21, and the image sensor 25 is disposed on the base body 20. Has been.

  Thus, the camera module 1 </ b> A is configured by the camera module drive mechanism 1 having the housing 2 </ b> A, the intermediate support 21 that supports the infrared cut glass 22, and the base body 20 on which the image sensor 25 is disposed.

  In the above configuration, as shown in FIG. 2, the upper leaf spring 5 includes an outer frame portion 5a on the housing 2A side, an inner frame portion 5b on the holder 9 side, an outer frame portion 5a, and an inner frame portion 5b. And a spring portion 5c having a spring property provided between them. Further, as shown in FIG. 3, the lower leaf spring 11 is provided between the outer frame portion 11a on the housing 2A side, the inner frame portion 11b on the holder 9 side, and between the outer frame portion 11a and the inner frame portion 11b. And a spring portion 5c having a spring property.

  Next, each component of the camera module drive mechanism 1 will be further described.

  As described above, the holder 9 holding the lens unit 26A is accommodated in the space in the housing 2A composed of the cover 2 and the base 13 so as to be displaceable in the optical axis direction of the lens unit 26A.

  An inner frame portion 5b of the upper leaf spring 5 and an inner frame portion 11b of the lower leaf spring 11 are respectively attached to the upper and lower cylindrical edge portions of the holder 9, and the outer frame portion 5a of the upper leaf spring 5 (FIG. 2). Is attached to the upper surface of the yoke 6 fixed to the base 13 of the housing 2A, and the outer frame portion 11a (see FIG. 3) of the lower leaf spring 11 is attached to the base 13 of the housing 2A.

  A plurality of magnet pieces 7 are bonded to the yoke 6 to constitute a magnetic circuit of the actuator mechanism 1. A coil 8 is disposed in the magnetic field formed by this magnetic circuit. The coil 8 is wound around the outer periphery of the holder 9, and the holder 9 can be displaced in the optical axis direction of the lens unit 26 </ b> A by supplying a current to the coil 8. In FIG. 5, a member indicated by reference numeral 12 is a conductor (flexible printed circuit board or the like) for supplying a current from an external power source to the coil 8, and a member indicated by reference numeral 4 is the upper surface of the upper leaf spring 5 as described above. The adjustment plate is attached to the upper plate spring 5 and adjusts the thickness of the upper leaf spring 5.

  Next, the upper leaf spring 5 and the lower leaf spring 11 will be further described with reference to FIGS.

  As shown in FIG. 2, the upper leaf spring 5 includes a rectangular outer frame portion 5a, a ring-shaped inner frame portion 5b on the holder 9 side, and a spring provided between the outer frame portion 5a and the inner frame portion 5b. And a spring portion 5c.

  A first positioning hole 5A that functions as a positioning hole for attaching the upper leaf spring 5 to the upper surface of the yoke 6 fixed to the base 13 of the housing 2A is provided between the outer frame portion 5a and the spring portion 5c. It has been.

  The first positioning holes 5A are provided at the four corners of the outer frame portion 5a and in the vicinity of the connecting portion with the spring portion 5c. The first positioning hole 5A engages with a positioning protrusion (not shown) provided on the upper surface side of the yoke 6 fixed to the base 13 of the housing 2A, and the upper leaf spring 5 is engaged with the base 13 of the housing 2A. Is positioned accurately on the upper surface side of the yoke 6 fixed to the head. Further, an adhesive region 30 for adhering the upper leaf spring 5 on the first positioning hole 5A to the upper surface of the yoke 6 fixed to the base 13 of the housing 2A via an adhesive (not shown) is provided in the first positioning hole 5A. Overlaid with.

  In addition, a second positioning hole 5 </ b> B that functions as a positioning hole when the upper plate spring 5 is attached to the holder 9 is provided between the inner frame portion 5 b and the spring portion 5 c of the upper plate spring 5.

  This 2nd positioning hole 5B is provided in the connection part 17 vicinity with the spring part 5c among the ring-shaped inner frame parts 5b (refer FIG. 2). The second positioning hole 5B engages with a positioning protrusion (not shown) provided on the holder 9 side to accurately position the upper leaf spring 5 on the holder 9 side. An adhesive region 30 for adhering the upper leaf spring 5 to the holder 9 via an adhesive (not shown) is formed on the second positioning hole 5B so as to overlap the second positioning hole 5B.

  Thus, the spring constant of the spring part 5c can be stabilized by positioning the both ends of the spring part 5c of the upper leaf spring 5 with high precision and firmly fixing to the housing 2A and the holder 9, respectively. .

  Next, the spring portion 5c of the upper leaf spring 5 will be further described. As shown in FIG. 2, the spring portion 5 c has a plurality of circular curved portions and a linear portion that connects the curved portions.

  Next, the lower leaf spring 11 will be described with reference to FIG.

  As shown in FIG. 3, the lower leaf spring 11 has a rectangular outer frame portion 11a on the housing 2A side, a ring-shaped inner frame portion 11b on the holder 9 side, and an outer frame portion 11a and an inner frame portion 11b. And a spring portion 11c having a spring property.

  A first positioning hole 11A that functions as a positioning hole for attaching the lower leaf spring 11 to the base 13 of the housing 2A is provided between the outer frame portion 11a and the spring portion 11c.

  The first positioning holes 11A are provided at the four corners of the outer frame portion 11a and in the vicinity of the connecting portion with the spring portion 11c. The first positioning hole 11A engages with a positioning protrusion (not shown) provided on the base 13 side of the housing 2A to accurately position the lower leaf spring 11 on the housing 2A side. In addition, an adhesive region 30 for adhering the lower leaf spring 11 to the base 13 of the housing 2A via an adhesive (not shown) is formed on the first positioning hole 11A so as to overlap the first positioning hole 11A.

  A second positioning hole 11 </ b> B that functions as a positioning hole when the lower plate spring 11 is attached to the holder 9 is provided in the vicinity of the connecting portion 17 between the inner frame portion 11 b and the spring portion 11 c of the lower plate spring 11. .

  The second positioning hole 11B engages with a positioning protrusion (not shown) provided on the holder 9 side to accurately position the lower leaf spring 11 on the holder 9 side. An adhesive region 30 for bonding the lower leaf spring 11 to the holder 9 via an adhesive (not shown) is formed on the second positioning hole 11B so as to overlap with the second positioning hole 11B.

  In FIG. 3, the outer frame 11a of the lower leaf spring 11 is provided with a connection terminal 11e connected to an external power source, and the inner frame 11b is provided with a connection terminal 11d connected to the coil 8 side. A current can flow from the power source to the coil 8 side via the lower leaf spring 11.

By the way, as shown in FIG. 3, the outer frame part 11a consists of a pair of outer frame members 11a ₁ and 11a ₂ which are separated from each other, so that the connection terminals 11e and 11e are not short-circuited. The inner frame portion 11b is composed of a pair of inner frame members 11b ₁ and 11b ₂ that are spaced apart from each other, so that the connection terminals 11d and 11d are not short-circuited.

  Next, the spring portion 11c of the lower leaf spring 11 will be further described. As shown in FIG. 3, the spring portion 11 c includes a plurality of circular curved portions and a linear portion that connects the curved portions.

  Next, a method for manufacturing the upper leaf spring 5 and the lower leaf spring 11 will be described with reference to FIGS. Each of the upper leaf spring 5 and the lower leaf spring 11 is a copper alloy containing at least one of Be, Ni, Cr, Si, Ti, Sn, in particular, a Cu—Ni—Sn alloy, a Cu—Ti alloy, etc. The metal plate (leaf spring material) 40 made of a Cu-based alloy is etched and manufactured.

  By the way, the upper leaf spring 5 and the lower leaf spring 11 are manufactured by substantially the same method. Hereinafter, a method for manufacturing the lower leaf spring 11 having the electrical connection terminals 11d and 11e will be described.

  Specifically, first, as shown in FIG. 5A, a metal plate (leaf spring material) 40 is prepared. As the leaf spring material 40, the above-described copper alloy can be used.

  Next, as shown in FIG. 5B, a casein resist (resist) 41 is applied on the leaf spring material 40 and dried. Next, a glass pattern is placed on the resist 41 and exposed for a predetermined time with an ultrahigh pressure mercury lamp. Next, after the resist 41 is developed, post-baking is performed, and the resist 41 having a predetermined pattern is formed on the leaf spring material 40.

  In this case, the resist 41 includes an upper resist 41 a disposed on the upper surface of the leaf spring material 40 and a lower resist 41 b disposed on the lower surface of the leaf spring material 40. Further, as shown in FIG. 5B, the upper resist 41a forms an opening 45 in the portion corresponding to the electrical connection terminals 11d, 11e of the lower leaf spring 11 in the leaf spring material 40, and the connection terminals 11d, The surface of the part corresponding to 11e is exposed. The lower resist 41b covers the back surface of the part corresponding to the connection terminals 11d and 11e.

  Thereafter, the leaf spring material 40 to which the resist 41 composed of the upper resist 41a and the lower resist 41b is applied is etched using an etching solution such as a ferric chloride solution. In this case, the outer shape is processed so that the leaf spring material 40 has a predetermined shape by etching. At the same time, the leaf spring material 40 is half-etched through the opening 45 of the upper resist 41a to form the electrical connection terminals 11d and 11e (FIG. 5C).

  Next, the resist 41 is stripped from the leaf spring material 40 using a resist stripping solution such as a sodium hydroxide solution (see FIG. 5D).

  Next, the leaf spring material 40 is cut and separated into a spring shape, and thus the lower leaf spring 11 is obtained from the leaf spring material 40.

  By the way, when the copper alloy containing any one or more of Be, Ni, Cr, Si, Ti, and Sn is used as the leaf spring material 40, the enriched area of the trace element is formed over the entire surface of the leaf spring material 40. In some cases, this concentrated area also causes a decrease in solder wettability.

  In the present embodiment, since the electrical connection terminals 11d and 11e are formed by half etching, the concentrated area remaining on the surface of the leaf spring material 40 can be removed from the surfaces of the connection terminals 11d and 11e. For this reason, it is possible to suppress a decrease in solder wettability of the connection terminals 11d and 11e. Further, the connection terminals 11d and 11e can be formed by half-etching, the surface area of the connection terminals 11d and 11e can be increased, and thereby the solder wettability can be kept good and the surface of the connection terminals 11d and 11e can be maintained. It is possible to improve the adhesion between the solder and the solder.

  Since the solder wettability can be kept good as described above, when mass production is taken into consideration, the joint portion between the coil 8 and the connection terminal 11d of the lower leaf spring 11 prevents the flux from being decomposed by heating and accumulation of dirt. Even when cream solder containing a flux with low activity due to heating is used, the lower plate spring 11 has good solder wettability, so that troubles such as poor connection do not occur.

  Further, by forming the connection terminals 11d and 11e by half etching, the surface area of the connection terminals 11d and 11e can be increased, and the adhesion between the surfaces of the connection terminals 11d and 11e and the solder can be improved.

  As described above, the lower leaf spring 11 can be manufactured by processing the outer shape by etching using the leaf spring material 40 and forming the connection terminals 11d and 11e by half etching.

  Similarly, the upper leaf spring 5 can be manufactured from the leaf spring material 40. In this case, since the upper leaf spring 5 does not have a connection terminal, the only difference is that it does not include the point of forming the connection terminal by half-etching, and the other is the same as the manufacturing method of the lower body spring 11. The upper leaf spring 5 can be manufactured.

  The “half-etching” in the present embodiment is not limited to etching the leaf spring material to approximately half the thickness, but etching to the extent that the concentrated area existing on the surface of the leaf spring material is removed. Shall be included.

  Next, the operation of the camera module drive mechanism will be described with reference to FIG.

  In the camera module drive mechanism shown in FIG. 4, a current is passed through the coil 8 via the lower leaf spring 11. As a result, an upward force acts on the holder 9, and the lens unit 26A can be lifted upward as a whole against the forces of the upper leaf spring 5 and the lower leaf spring 11 (see FIG. 4).

  Further, by adjusting the amount of current flowing through the coil 8, the force that moves the holder 9 upward is changed, and the balance between the force of the upper leaf spring 5 and the lower leaf spring 11 is made, so that the holder 9 moves up and down. And its position can be adjusted.

  In this case, the first positioning holes 5A and 11A are provided in the vicinity of the connecting portion of the outer plate portions 5a and 11a of the upper plate spring 5 and the lower plate spring 11 with the spring portions 5c and 11c, and the inner frame portions 5b and 11b. Second positioning holes 5B and 11B are provided in the vicinity of the connecting part 17 with the spring parts 5c and 11c, and further, an adhesive region 30 is provided on the first positioning holes 5A and 11A and the second positioning holes 5B and 11B. As a result, both ends of the spring portions 5c and 11c having the spring properties of the upper leaf spring 5 and the lower leaf spring 11 are accurately attached to the yoke 6, the base 13 and the holder 9 fixed to the base 13 of the housing 2A. Positioning can be performed well, and both end portions of the spring portions 5c and 11c can be firmly fixed to the yoke 6, the base 13 and the holder 9 fixed to the base 13 of the housing 2A.

  In this way, both ends of the spring portions 5c, 11c of the upper leaf spring 5 and the lower leaf spring 11 are accurately positioned on the yoke 6, the base 13 and the holder 9 fixed to the base 13 of the housing 2A, and By fixing firmly, the spring constant of the spring parts 5c and 11c can be stabilized.

  Thus, a camera module drive mechanism having stable spring characteristics can be obtained.

  Specifically, when a current is passed through the coil 8 via the lower leaf spring 11, an interaction occurs between the current and the magnetic field of the magnet 7, and the holder 9 moves up and down. At this time, the upper leaf spring 5 and the lower leaf spring 11 suppress the movement of the holder 9 according to the spring constant k.

  In this case, three elements (i) (ii) (iii) consisting of (i) a current flowing through the coil 8, (ii) a magnetic force of the magnet 7, and (iii) a spring constant of the upper leaf spring 5 and the lower leaf spring 11 ), The focus of the lens unit 26A can be adjusted by moving the holder 9 up and down and adjusting its position.

  Therefore, in order to perform the adjustment with the lens unit 26A with high accuracy, it is required to determine the above three elements (i), (ii), and (iii), particularly the element (iii) with high accuracy and to design stably. Yes.

  As described above, by stabilizing the spring constants of the spring portions 5c and 11c, among the above three elements (i), (ii), and (iii), in particular, (iii) the upper leaf spring 5 and the lower leaf spring 11 The spring constant can be stabilized. Accordingly, the vertical movement of the holder 9 and the position adjustment thereof can be performed with high accuracy, and the focal point by the lens unit 26A can be adjusted with high accuracy.

  Further, since the connection terminals 11d and 11e of the lower leaf spring 11 are formed by half-etching as described above, it is possible to remove as much as possible the trace element concentration area that hinders the solder wettability remaining on the surface. (See FIGS. 5A to 5D). For this reason, the solder wettability on the surfaces of the connection terminals 11d and 11e of the lower leaf spring 11 can be kept good. Further, since the connection terminals 11d and 11e are formed by half-etching, the surface area can be increased, thereby improving the adhesion between the connection terminals 11d and 11e and the solder.

  Accordingly, in consideration of mass production, cream solder containing a flux with low activity by heating at the joint between the coil 8 and the connection terminal 11d of the lower leaf spring 11 so that the flux is not decomposed by heating and dirt is not accumulated in the lens or the like. Even in the case where is used, since the solder wettability of the connection terminal 11d of the lower leaf spring 11 is kept good, a failure such as poor connection does not occur.

DESCRIPTION OF SYMBOLS 1 Camera module drive mechanism 1A Camera module 2 Cover 2A Housing | casing 4 Adjustment board 5 Upper leaf | plate spring 5a Outer frame part 5b Inner frame part 5c Spring part 5A 1st positioning hole 5B 2nd positioning hole 6 Yoke 7 Magnet piece 8 Coil 9 Holder 11 Lower leaf spring 11a Outer frame portion 11b Inner frame portion 11c Spring portion 11A First positioning hole 11B Second positioning hole 12 Conductor (flexible printed circuit board, etc.)
13 Base 17 Connecting portion 18 Wide portion 20 Base 21 Intermediate support 22 Infrared cut glass 25 Image sensor 26 Lens 26A Lens unit 30 Adhesion region 32 Curved portion 33 Straight portion 40 Leaf spring material 41 Resist 41a Upper resist 41b Lower resist 45 Opening

Claims (3)

In the manufacturing method of the leaf spring for the drive mechanism of the camera module including the electrical connection terminal,
Preparing a leaf spring material made of a Cu-based alloy;
Etching the leaf spring material with a resist to form an outer shape, and half-etching to form an electrical connection terminal;
Removing the resist from the leaf spring material after etching and half-etching;
A method of manufacturing a leaf spring for a drive mechanism of a camera module.   3. A leaf spring material for a driving mechanism of a camera module according to claim 1, wherein a leaf spring material made of a copper alloy containing at least one of Be, Ni, Cr, Si, Ti, and Sn is prepared. Method.   A leaf spring for a drive mechanism of a camera module, comprising an electrical connection terminal obtained by the method for producing a leaf spring for a drive mechanism of a camera module according to claim 1.

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