JP2009122360A - Lens drive device, spring member and manufacturing method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lens drive device, which is provided with a spring member in which accuracy of a spring constant of its plate spring-shaped arm part is improved, and to provide the spring member and a manufacturing method therefor. <P>SOLUTION: The spring member 14y has the plate spring-shaped arm part 140 which connects a support body side fixing part 149 and a movable body side fixing part 148. To manufacture the spring member 14y, the arm part 140 is formed in a cutting process to a thin metal plate by press working or by etching processing utilizing a photo lithography technique. In a laser trimming process, the spring constant of the arm part is measured. Based on the measurement results, a cut portion 145 for extending a second slit part 142 is formed by a laser. The spring constant is corrected by changing the length dimension of the arm part 140. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a lens driving device in which a movable body including a lens is supported by a spring member so as to be displaceable in the optical axis direction, a spring member including a plate spring-like arm portion, and a method of manufacturing the same.

  A camera mounted on a camera-equipped mobile phone, a digital camera, or the like has a lens driving device that drives the lens to be displaced in the optical axis direction. Such a lens driving device includes a support, a moving body including a lens, and a spring member that supports the moving body so as to be movable along the lens optical axis. The spring member is disposed on the support side. A support-side fixing portion to be fixed, a moving-body-side fixing portion fixed to the moving-body side, and a plurality of leaf spring-like arm portions that connect the support-side fixing portion and the moving-body-side fixing portion (Patent Document) 1).

Here, the spring member is generally manufactured by cutting a thin plate by wet etching using a photolithography technique.
JP 2006-201525 A

  In such a lens driving device, the moving body is driven in the optical axis direction by a magnetic driving mechanism configured between the support body side and the moving body side, and the movement of the moving body is regulated by a spring member, and the stop position of the moving body is set. Stipulate. For this reason, although high precision is calculated | required with respect to the spring constant of the arm part of a spring member, in the conventional manufacturing method, there exists a problem that such a highly accurate spring constant cannot be obtained. Such a problem is not limited to the spring member used in the lens driving device, but can be applied to all spring members used in devices that regulate the position of the moving body by the spring member. However, especially in the lens driving device, as the size and thickness of the lens driving device are reduced, the demand for the thinning of the spring member and the narrowing of the arm portion is severe, and accordingly, the control of the spring constant is becoming difficult.

  In view of the above problems, an object of the present invention is to provide a lens driving device including a spring member with improved accuracy of a spring constant of a plate spring-like arm portion, the spring member, and a manufacturing method thereof. It is in.

  In order to solve the above-described problems, in the present invention, a lens driving device including a support, a moving body including a lens, and a spring member that supports the moving body so as to be movable along the lens optical axis. The spring member includes a plurality of support-side fixing portions that are fixed to the support side, a moving-body-side fixing portion that is fixed to the moving-body side, and a plurality of links that connect the support-side fixing portion and the moving-body-side fixing portion. A plate spring-like arm portion, and at least one of the plurality of arm portions is provided with a laser cutting portion at a part of the edge portion.

  That is, in a method of manufacturing a lens driving device including a support, a moving body including a lens, and a spring member that supports the moving body along the lens optical axis, the spring member is on the support side. A support body side fixing portion fixed to the movable body side, a moving body side fixing portion fixed to the mobile body side, and a plurality of leaf spring-like arm portions connecting the support body side fixing portion and the mobile body side fixing portion, In manufacturing the spring member, the thin plate is cut to form the support side fixing portion, the movable body side fixing portion, and the arm portion, and the spring constant of the arm portion formed by the cutting step is determined. And performing a laser trimming step of correcting the spring constant by changing the shape and dimensions of the arm portion with a laser based on the measurement result of the spring constant.

  In the present invention, after forming the support member side fixing portion, the movable body side fixing portion, and the arm portion of the spring member in the cutting step, the laser trimming step measures the spring constant of the arm portion, and based on the measurement result of the spring constant. Then, a laser trimming process is performed to correct the spring constant. For this reason, even if the accuracy of the spring constant is low only by the cutting process, the spring member has a highly accurate spring constant after the laser trimming process. Therefore, when the position of the moving body is controlled by the biasing force of the spring member, the accuracy of the spring constant of the spring member is high, so that the position of the moving body can be controlled with high accuracy.

  In the lens driving device to which the present invention is applied, the edge portion of the arm portion other than the cutting portion by the laser is, for example, a cutting portion by press processing or etching processing using a photolithography technique. That is, in the manufacturing method of the lens driving device to which the present invention is applied, in the cutting step, for example, the support-side fixing portion, the moving-body-side fixing portion by the press processing on the thin plate or the etching processing using photolithography technology, And forming the arm portion.

  In the present invention, in the spring member, the laser cutting portion is preferably formed so as to extend a length of the arm portion by extending a notch sandwiching the arm portion on both sides. If comprised in this way, compared with the case where the shape of an arm part is changed, even when the width dimension of an arm part is narrow, laser trimming is easy.

  In this invention, the said arm part is extended in the circumferential direction, and the said spring member is cut | disconnected toward the connection part of the said arm part and the said mobile body side fixing | fixed part inside the said arm part. A slit part, and a second slit part cut out toward a connecting part between the arm part and the support side fixing part outside the arm part, and the cutting part by the laser is the first slit part or A configuration may be employed in which the second slit portion is extended to extend the length of the arm portion. If comprised in this way, compared with the case where the shape of an arm part is changed, even when the width dimension of an arm part is narrow, laser trimming is easy.

  In this case, in any of the plurality of arm portions, the first slit portion located inside the arm portion is located outside the arm portion formed at a position adjacent to the arm portion in the circumferential direction. It is preferable that the second slit portion forms a notch connected in the circumferential direction. If comprised in this way, when manufacturing a spring member from a thin plate, since the cutting pattern with respect to a thin plate can be simplified, while the cutting process of a spring member can be simplified, the precision of a cutting pattern can be raised.

  In the present invention, it is preferable that the laser cut portion is formed so as to extend the length of the arm portion by extending the second slit portion. Since the connecting part between the arm part and the movable body side fixed part is often set in shape and width in consideration of its strength and the like, when the first slit part is extended by the laser, the arm part and the movable body side fixed part are fixed. There is a risk that the strength of the connecting portion with the portion may be impaired, but such a problem can be avoided when the second slit portion is extended by a laser.

  In the present invention, the movable body side fixed portion is formed in an annular frame shape to which the plurality of arm portions are connected, and the plurality of arm portions are configured to be curved along the movable body side fixed portion. be able to.

  In the present invention, a support body side fixing portion fixed to the support body side, a moving body side fixing portion fixed to the moving body side, and a plate spring-like arm portion connecting the support body side fixing portion and the moving body side fixing portion. The provided spring member is characterized in that the arm portion includes a laser cutting portion at a part of the edge portion.

  That is, in the present invention, a support body side fixing portion fixed to the support body side, a moving body side fixing portion fixed to the moving body side, and a leaf spring-like arm connecting the support body side fixing portion and the moving body side fixing portion. In the method of manufacturing a spring member provided with a portion, a cutting step of cutting a thin plate to form the support side fixing portion, the moving body side fixing portion, and the arm portion, and a spring of the arm portion formed by the cutting step A laser trimming step of measuring a constant and correcting the spring constant by changing a shape and a dimension of the arm portion with a laser based on a measurement result of the spring constant.

  In the present invention, after forming the support member side fixing portion, the movable body side fixing portion, and the arm portion of the spring member in the cutting step, the laser trimming step measures the spring constant of the arm portion, and based on the measurement result of the spring constant. Then, a laser trimming process is performed to correct the spring constant. For this reason, even if the accuracy of the spring constant is low only by the cutting process, the spring member has a highly accurate spring constant after the laser trimming process.

  In the spring member to which the present invention is applied, the edge portion other than the cutting portion by the laser in the arm portion is a cutting portion by, for example, press processing or etching processing using a photolithography technique. That is, in the method for manufacturing a spring member according to the present invention, in the cutting step, for example, the support-side fixing portion, the movable body-side fixing portion, and the movable body-side fixing portion are formed by pressing the thin plate or etching using a photolithography technique. An arm part is formed.

  In the present invention, after forming the support member side fixing portion, the movable body side fixing portion, and the arm portion of the spring member in the cutting step, the laser trimming step measures the spring constant of the arm portion, and based on the measurement result of the spring constant. Then, a laser trimming process is performed to correct the spring constant. For this reason, even if the accuracy of the spring constant is low only by the cutting process, the spring member has a highly accurate spring constant after the laser trimming process. Therefore, when the spring member to which the present invention is applied is used in the lens driving device, the accuracy of the spring constant of the spring member is high, so that the position of the moving body can be controlled with high accuracy.

  The best mode for carrying out the present invention will be described below with reference to the drawings. The lens driving device described below can be attached to various electronic devices in addition to the camera-equipped mobile phone. For example, it can be used for a thin digital camera, PHS, PDA, bar code reader, surveillance camera, camera for checking the back of a car, a door having an optical authentication function, and the like.

(Entire configuration of lens driving device)
1A and 1B are an external view and an exploded perspective view, respectively, of a lens driving device to which the present invention is applied as viewed obliquely from above.

  1A and 1B, a lens driving device 1 according to the present embodiment is a thin camera used for a camera-equipped mobile phone or the like. For example, three lenses 121 are placed along a subject (object side) along the optical axis direction. For moving in both directions, A direction (front side) approaching and B direction (rear side) approaching the opposite side (image side) to the subject, and has a substantially rectangular parallelepiped shape. The lens driving device 1 generally includes a moving body 3 that holds a cylindrical lens holder 12 that includes three lenses 121 and a fixed stop inside, and a lens drive that moves the moving body 3 along the optical axis direction. It has a mechanism 5 and a support 2 on which a lens driving mechanism 5 and a moving body 3 are mounted. The moving body 3 includes a cylindrical sleeve 13, and a cylindrical lens holder 12 is fixed to the inside thereof. Therefore, the outer shape of the moving body 3 is defined by the sleeve 13 and has a substantially cylindrical shape.

  The support 2 includes a rectangular holder 19 for holding an image pickup device (not shown) on the image side, a box-shaped yoke 18 and a spacer 11 located on the subject side, and the yoke 18 and the spacer 11. Are formed with circular incident windows 110 and 180 for taking light from the subject into the lens 121. The yoke 18 is made of a ferromagnetic plate such as a steel plate, and constitutes a linkage magnetic field generator 4 that generates a linkage magnetic field in the drive coil 30 held by the sleeve 13 together with the magnet 17 as will be described later. Note that the side plate portion 181 of the yoke 18 covers the upper surface of the holder 19.

  The lens driving mechanism 5 includes a drive coil 30 wound around the outer peripheral surface of the sleeve 13 and a linkage magnetic field generator 4 that generates a linkage magnetic field in the drive coil 30. The drive coil 30 and the linkage magnetic field generator 4 constitutes a magnetic drive mechanism 5a. The interlinkage magnetic field generator 4 includes four magnets 17 that face the drive coil 30 on the outer peripheral side. The yoke 18 is also used as a component of the lens driving mechanism.

  The yoke 18 has a box shape that covers the side surface and the upper surface of the drive coil 30, and can reduce leakage magnetic flux from a magnetic path formed between the magnet 17 and the drive coil 30. The linearity between the amount of movement of the sleeve 13 and the current passed through the drive coil 30 can be improved. In the yoke 18, the pair of side surfaces 181 facing each other is formed in a flat shape, and the other pair of side surfaces 182 facing each other protrudes outwardly in a stepped manner at the center because both ends 182 a are recessed inward. A convex portion 182b is formed.

  In this embodiment, each of the four magnets 17 has a substantially triangular prism shape, and is fixed to the four corners of the inner peripheral surface of the yoke 18 in a state of being separated in the circumferential direction. Each of the four magnets 17 is divided into two in the optical axis direction, and in any case, the inner surface and the outer surface are magnetized to different poles. In the four magnets 17, for example, the inner surface is magnetized to the N pole in the upper half, the outer surface is magnetized to the S pole, and the inner surface is magnetized to the S pole in the lower half, and the outer surface is magnetized to the N pole. It is magnetized. Therefore, the drive coil 30 is divided into two corresponding to the upper half and the lower half of the magnet 17, and the winding direction of the divided drive coil is opposite. As described above, if the magnet 17 is divided into four corners, a thin portion is generated in the magnet 17 even when the gap between the yoke 18 and the sleeve 13 is narrow in the central portion of the side portion of the yoke 18. This can be prevented, the strength of the magnet 17 can be increased, and the magnetic force of the magnet 17 can be efficiently applied to the drive coil 30 mounted on the moving body 3. In addition, by effectively using the four corner spaces between the moving body 3 and the yoke 18 as the arrangement space for the magnets 17, the entire lens driving device 1 can be reduced in size.

  The lens driving mechanism 5 further includes spring members 14x and 14y between the holder 19 and the sleeve 13 and between the spacer 11 and the sleeve 13, respectively. The two spring members 14x and 14y are both made of metal such as beryllium copper or SUS steel, and are formed by pressing a thin plate having a predetermined thickness or etching using a photolithography technique.

  Although the detailed configuration of the spring members 14x and 14y will be described later, the spring member 14x is connected to the holder 19 and the sleeve 13, and is supported by the support 2 so that the movable body 3 is movable along the lens optical axis. State. The spring member 14y is connected to the spacer 11 and the sleeve 13, and the movable body 3 is supported by the support body 2 so as to be movable along the lens optical axis.

  Further, of the spring members 14x and 14y, the spring member 14x disposed on the holder 19 side is divided into two spring pieces 14a and 14b, and two ends of the drive coil 30, a winding start end and a winding end. The end portions are respectively connected to the spring pieces 14a and 14b. At that time, of the two terminals of the drive coil 30, the object-side terminal passes under a groove (not shown) formed on the outer peripheral surface of the sleeve 13, and then dive under the drive coil 30 and spring pieces. It is routed to 14a. In the spring member 14x, the spring pieces 14a and 14b are each formed with a terminal 12c, and the spring member 14x (spring pieces 14a and 14b) also functions as a power supply member for the drive coil 30.

  In this embodiment, the lens driving mechanism 5 further includes a ring-shaped magnetic piece 130 held at the upper end of the sleeve 13, and the magnetic piece 130 is attracted by the attractive force acting between the magnet 17. An urging force in the optical axis direction is applied to the moving body 3. For this reason, since it is possible to prevent the mobile body 3 from being displaced by its own weight when no current is applied, it is possible to maintain the mobile body 3 in a desired posture and to further improve the impact resistance. Further, the magnetic piece 130 acts as a kind of back yoke, and can reduce the leakage magnetic flux from the magnetic path formed between the magnet 17 and the drive coil 30. In addition, as a magnetic piece, a rod-shaped magnetic body may be used.

  The spacer 11 is attached to the inner surface of the top plate portion 185 of the yoke 18 and has a plate portion 115 in which an incident window 110 is formed at the center. At the four corners of the plate portion 115, small protrusions 112 protruding toward the image sensor are formed.

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

  Protrusions 13a and 13b projecting toward the outer peripheral side are formed on the outer peripheral surface of the sleeve 13, and the protrusions 13a and 13b are located on both sides of the lens 121 (lens holder 12) with respect to the optical axis X. It protrudes in the orthogonal direction. When the sleeve 13 (moving body 3) configured as described above is arranged in the support body 2, the projections 13a and 13b are arranged inside the convex portion 182b of the yoke 18 between the adjacent magnets 17. Here, the convex portion 182b extends in the optical axis direction, and the convex portion 182b allows the movement of the protrusions 13a and 13b in the optical axis direction when the moving body 3 moves in the optical axis direction. Function as. Further, when the moving body 3 is displaced in a direction (right and left direction or circumferential direction) perpendicular to the optical axis direction due to an impact or the like, the protrusions 13a and 13b come into contact with the inner wall of the convex portion 182b of the yoke 18, so that the movement further takes place. Displacement in the left-right direction orthogonal to the optical axis direction of the body 3 and rotational displacement in the circumferential direction can be prevented.

  A plurality of small protrusions 13y for connecting the spring member 14y are formed in the circumferential direction on the upper end surface (the subject-side end surface) of the sleeve 13, and on the lower end surface (the end surface on the image sensor side) of the sleeve 13. Has a plurality of small protrusions 13x for connecting the spring member 14x in the circumferential direction.

(Basic operation)
FIG. 2 is an explanatory diagram schematically showing the operation of the lens driving device 1 shown in FIG. The left half of FIG. 2 shows a view when the sleeve 13 is at an infinite position (normal photographing position), and the right half of FIG. 2 is that the sleeve 13 is at a macro position (close-up photographing position). Figure shows when.

  In the lens driving device 1 of the present embodiment, the moving body 3 is normally located on the imaging element side (image side). When a current in a predetermined direction is passed through the driving coil 30 in such a state, the driving coil 30 is moved. Each receive an upward (front) electromagnetic force. Thereby, the sleeve 13 to which the drive coil 30 is fixed starts to move toward the subject side (front side). At this time, elastic forces that restrict the movement of the sleeve 13 are generated between the spring member 14y and the front end of the sleeve 13 and between the spring member 14x and the rear end of the sleeve 13, respectively. For this reason, when the electromagnetic force that attempts to move the sleeve 13 to the front side and the elastic force that restricts the movement of the sleeve 13 are balanced, the sleeve 13 stops. At that time, the sleeve 13 (moving body 3) can be stopped at a desired position by adjusting the amount of current flowing through the drive coil 30 according to the elastic force acting on the sleeve 13 by the spring members 14x and 14y. In this embodiment, since the spring members 14x and 14y in which a linear relationship is established between the elastic force (stress) and the displacement amount (strain amount) are used, the amount of movement of the sleeve 13 and the current flowing through the drive coil 30 are Linearity can be improved. In addition, since the two spring members 14x and 14y are used, a large balance force is applied in the direction of the optical axis X when the sleeve 13 is stopped, and centrifugal force and impact force are applied in the direction of the optical axis X. Even if other forces such as these work, the sleeve 13 can be stopped more stably. Further, in the lens driving device 1, the sleeve 13 is not stopped by colliding with a collision material (buffer material) or the like, but is stopped using a balance between electromagnetic force and elastic force. Therefore, it is possible to prevent the occurrence of a collision sound.

(Detailed configuration of the spring member 14y)
The configuration of the spring member 14y will be described with reference to FIGS. FIGS. 3A and 3B are a plan view of the spring member 14y used in the lens driving device to which the present invention is applied, and a plan view showing the configuration of the spring member 14y before laser trimming.

  As shown in FIG. 1 and FIG. 3A, the spring member 14y is fixed to the support body side fixing portion 149 having a rectangular frame shape fixed to the support body 2 (spacer 11) and the movable body 3 (sleeve 13). An annular moving body side fixing portion 148, and four leaf spring-like arm portions 140 that connect the supporting body side fixing portion 149 and the moving body side fixing portion 148. The support-side fixing portion 149 is formed with small holes 149a into which the small protrusions 112 of the spacer 11 are fitted in each of the four corner portions. The small protrusion 112 is fitted into the small hole 149a so that the support-side fixing portion 149 and the spacer 11 are fitted. After the positioning, the support-side fixing portion 149 and the spacer 11 are fixed by a method such as applying and curing an adhesive in the small hole 149a. Further, in the movable body side fixing portion 148, rectangular concave portions 148b recessed inward in the radial direction are formed in portions facing the four corner portions of the supporting body side fixing portion 149, and the rectangular concave portions 148b are disposed on both sides in the circumferential direction. A small hole 148a is formed so as to be sandwiched between the two. Therefore, after the small protrusion 13y is fitted in the rectangular recess 148b and the movable body side fixing portion 148 and the sleeve 13 are positioned, the moving body side fixing portion 148 and the sleeve 13 are applied by a method such as applying and curing an adhesive in the small hole 148a. And fixing.

  The spring member 14y is formed by pressing a thin metal plate or etching using a photolithography technique. At that time, between the movable body side fixing portion 148 and the supporting body side fixing portion 149, Four notches 143 extending in the circumferential direction are formed, and the four arm portions 140 extending in the circumferential direction are formed by the notches 143.

  That is, each of the four notches 143 extends in the circumferential direction. However, in the example shown in FIG. 3A, the notches 143 extend so as to be shifted from the inner circumferential side to the outer circumferential side at a midway position in the clockwise CW direction. The notches 143 that are adjacent to each other in the circumferential direction overlap with each other in a portion corresponding to about ½ of the length direction in the radial direction. For this reason, a narrow arm portion 140 whose inner peripheral edge portion is defined by a portion located on the counterclockwise CCW side in the notch 143 is formed in a portion where the notches 143 adjacent in the circumferential direction overlap each other. The outer peripheral edge portion of the arm portion 140 is defined by a portion located on the clockwise CW side in the notch 143 adjacent to the notch 143 in the counterclockwise CCW direction.

  In the spring member 14y configured as described above, all of the four notches 143 extend in a slit shape. Therefore, in the spring member 14y, the arm part 140 and the movable body side fixing part 148 are located inside the arm part 140. The first slit portion 141 is cut toward the connecting portion with the arm portion 140, and the second slit portion 142 is cut outside the arm portion 140 toward the connecting portion between the arm portion 140 and the support side fixing portion 149. The length dimension of the arm part 140 is prescribed | regulated by the cut depth of this 1st slit part 141 and the 2nd slit part 142. In other words, in any of the four arm portions 140, the first slit portion 141 located inside the arm portion 140 and the outside of the arm portion 140 formed at a position adjacent to the arm portion 140 in the circumferential direction. The second slit portion 142 located at a portion constitutes a cutout 143 connected in the circumferential direction, and the length of the cutout 143 defines the length dimension of the arm portion 140. In this embodiment, the length dimension of the arm part 140 is 3 to 5 mm.

(Manufacturing method of the spring member 14y)
FIGS. 4A and 4B are an explanatory view of a laser trimming process when the spring member 14y is manufactured, and an explanatory view of a laser cut portion.

  In the lens driving device 1 of the present embodiment, the spring member 14y restricts the position of the moving body 3 by the urging force as described with reference to FIG. For this reason, high accuracy is required for the spring constant of the arm portion 140. Therefore, in this embodiment, the spring member 14y is manufactured by the following manufacturing method.

  First, in the cutting process, as shown in FIG. 3 (b), a notch 143 or the like is formed in the thin plate by pressing a metal thin plate such as beryllium copper or SUS steel, or by etching using a photolithographic technique. Then, the support body side fixing portion 149, the moving body side fixing portion 148, and the arm portion 140 are formed.

  Next, in the laser trimming process, the spring constant of the arm part 140 formed by the cutting process is measured, and the spring constant is corrected by changing the shape and dimensions of the arm part 140 with a laser based on the measurement result of the spring constant. . Specifically, in the spring member 14y shown in FIG. 3B, the second slit portion 142 of both ends (the first slit portion 141 and the second slit portion 142) of any of the four notches 143. A laser spot is irradiated to the end of the arm portion, and a partial cut is made at the connecting portion between the arm portion 140 and the support side fixing portion 149 so as to extend the second slit portion 142.

  More specifically, as shown in FIG. 4A, a laser beam (for example, YAG laser / wavelength 1064 nm) is applied to the connecting portion between the arm portion 140 and the support-side fixing portion 149, and the laser beam is emitted. The position of the spot P is shifted. The conditions at that time are, for example, a scanning speed of 50 mm / s, a Q switch frequency (laser on-off frequency) of 100 kHz, and a repetition number of 50 times. As a result, for example, as shown in FIG. 4B, a laser cut portion 145 is formed so as to extend the second slit portion 142. Therefore, most of the edge of the arm portion 140 is a linear or curved cut portion by press processing on a thin plate or etching processing using a photolithography technique, but the arm portion 140 and the support-side fixing portion 149 A cut portion 145 by a laser in the laser trimming process is formed in the connecting portion. In the cut portion 145, fine irregularities 145a are formed. That is, when cutting with a laser, a groove called a kerf is formed, and a groove is continuously formed in the cut portion 145, but a trace of the groove shape remains, so that press working or photolithography technology is used. The portion cut by the etching process and the cut portion 145 by the laser are different in the shape of the cut edge, and even when the unevenness 145a is hardly left, the laser cut generates heat and can be discolored by heat. Therefore, there is a difference in color between the portion cut by the press processing or the etching processing using the photolithography technique and the cut portion 145 by the laser. Therefore, it is possible to distinguish a portion cut by an etching process using a press process or a photolithography technique and a cut part 145 by a laser.

  Here, the laser irradiation may be performed from one side of the spring member 14y or from both sides, but the situation where the arm part 140 warps to one side by the heat when the laser is irradiated. From the viewpoint of avoiding this, it is preferable to perform laser irradiation from both surfaces of the spring member 14y.

In this embodiment, trimming by laser is performed on any of the four arm portions 140. Therefore, as shown in FIG. 3A, in any of the four arm portions 140, a laser cut portion 145 is formed at the connecting portion between the arm portion 140 and the support-side fixing portion 149, and the arm portion 140 is formed. The length dimension of is extended by the dimension cut by the laser. When cutting with such a laser, the cutting dimension is set based on the result of measuring the spring constant of the arm portion 140. That is, the spring constant of the arm portion 140, longitudinal elastic modulus, thickness, respectively the length, k, E, b, t, When a, which are the following relation ^{k = E · b · t 3} /4 · a ³
Therefore, if the length dimension a of the arm part 140 is corrected, the spring constant k can be corrected.

  In the laser trimming step, the spring constant of the arm part 140 may be measured for one spring member 14x and then trimmed by laser may be performed, or the spring constant of the arm part 140 may be set for all of the plurality of spring members 14x. After the measurement, each of the plurality of spring members 14x may be trimmed with a laser. In any case, after the arm portion 140 is designed so that the spring constant becomes larger than the final target value, a method of performing trimming by laser for all the spring members 14x may be employed, or the spring constant may be the final target value. After the arm unit 140 is designed so that only the spring member 14x deviated from the final target value is trimmed by laser, a method of performing trimming by laser may be employed.

(Main effects of this form)
FIG. 5 is an explanatory diagram of the shape of a cut portion by a laser in a spring member to which the present invention is applied. FIG. 6 is an explanatory diagram showing changes in the spring constant before and after laser trimming in the spring member to which the present invention is applied.

  In the spring member 14y to which the present invention is applied, the spring constant of the arm portion 140 is corrected to an optimal value by forming the cut portion 145 by the laser in the laser trimming process. Therefore, the spring member 14y with high accuracy of the spring constant can be manufactured, and in the lens driving device 1 using the spring member 14y, the position of the moving body 3 can be controlled with high accuracy.

  In this embodiment, since the length of the arm portion 140 is increased by the laser trimming process, unlike the case where the shape of the arm portion 140 is changed, the trimming can be easily performed even when the width of the arm portion 140 is narrow. Can be performed.

  In this embodiment, when extending the length of the arm part 140 in the laser trimming step, the length of the arm part 140 is increased by extending the second slit part 142 of the first slit part 141 and the second slit part 142. The dimensions are extended. For this reason, generation | occurrence | production of the bad effect by laser trimming is suppressed. That is, since the connecting portion between the arm portion 140 and the movable body side fixed portion 148 is often set in shape and width in consideration of its strength and the like, when the first slit portion 141 is extended by a laser, the arm The strength of the connecting portion between the portion 140 and the movable body side fixing portion 148 may be impaired, but such a problem can be avoided when the second slit portion 142 is extended by a laser.

  Here, the shape of the cut portion 145 by the laser can be arbitrarily set according to the irradiation condition of the laser to the end portion of the second slit portion 142 shown in FIG. For example, as shown in FIG. 5B, the width dimension (for example, 0.05 mm) narrower than the width dimension (for example, 0.155 mm) of the second slit section 142 from the substantially central portion of the second slit section 142 in the width direction. ) Of the cut portion 145 having a short length (for example, 0.3 mm) can be employed. Further, as shown in FIG. 5C, for example, a cut portion 145 having a width dimension of 0.05 mm is formed with a length dimension of 0.3 mm from a substantially central portion in the width direction of the second slit portion 142. Can be adopted. Further, as shown in FIG. 5 (d), for example, a cut portion 145 having a width dimension of 0.1 mm is formed from a substantially central portion in the width direction of the second slit portion 142 with a length dimension of 0.5 mm. Can be adopted.

  When such a form is adopted, as shown in FIG. 6, the spring member 14y without laser processing shown in FIG. 5A has a spring constant of 5.55, but the spring shown in FIG. The member 14y can correct the spring constant to 5.11, the spring member 14y shown in FIG. 5C can correct the spring constant to 4.68, and the spring member 14y shown in FIG. 54 can be corrected.

  In addition, the shape of the cutting part 145 by the laser is not limited to the state shown in FIGS. 5B to 5D, for example, as shown in FIG. As shown in FIG. 5 (f), a portion in which the laser cut portion 145 is extended from a portion located on the portion 140 side, a portion located on the opposite side of the arm portion 140 from the end portion of the second slit portion 142. Alternatively, a configuration in which the cut portion 145 by the laser is extended, or a shape in which the cut portion 145 by the laser is extended wider than the second slit portion 142 as shown in FIG.

(Detailed configuration of the spring member 14x)
The configuration of the spring member 14x will be described with reference to FIGS. 7A and 7B are a plan view of the spring member 14y used in the lens driving device 1 to which the present invention is applied, and a plan view showing a state before the spring member 14y is separated from the frame. In addition, since the basic structure of the spring member 14x is the same as that of the spring member 14y, as much as possible, common portions are denoted by the same reference numerals, and description thereof is omitted.

  As shown in FIGS. 1 and 7A, the spring member 14x includes a support-side fixing portion 149 that is fixed to the support 2 (holder 19) and an annular shape that is fixed to the moving body 3 (sleeve 13). The movable body side fixing portion 148, and four leaf spring-like arm portions 140 that connect the supporting body side fixing portion 149 and the moving body side fixing portion 148 are provided. Unlike the spring member 14y, the spring member 14x is used as a power feeding member for the drive coil 30, and thus is divided into two spring pieces 14a and 14b. That is, in the spring member 14x, the support-side fixing portion 149 is divided into four, and the support-side fixing portion 149 is also equally divided into two by the slit 147a. However, until the spring member 14x is incorporated in the lens driving device 1, as shown in FIG. 7B, the two spring pieces 14a and 14b are connected by the frame 147 and the connecting plate portion 147d, and the lens After being incorporated in the drive device 1, the cut portions 147b and 147c are cut and divided into two spring pieces 14a and 14b.

  Similarly to the spring member 14y, the spring member 14x is formed by pressing a thin metal plate or etching using a photolithography technique. At that time, the movable body side fixing portion 148 and the supporting body side fixing portion 149 Between the two, four notches 143 extending in the circumferential direction are formed, and by the notches 143, four arm portions 140 extending in the circumferential direction are formed. Here, each of the four notches 143 extends in the circumferential direction, but in the example shown in FIGS. 7A and 7B, the inner circumferential side to the outer circumferential side at a midway position in the clockwise CW direction. It extends so as to slip. For this reason, an arm portion 140 whose inner peripheral edge portion is defined by a portion located on the counterclockwise CCW side in the notch 143 is formed in a portion where the notches 143 adjacent in the circumferential direction overlap each other. The outer peripheral edge portion of the portion 140 is defined by a portion located on the clockwise CW side in the notch 143 adjacent to the notch 143 in the counterclockwise CCW direction.

  In the spring member 14y configured as described above, all of the four notches 143 extend in a slit shape. Therefore, in the spring member 14y, the arm part 140 and the movable body side fixing part 148 are located inside the arm part 140. The first slit portion 141 is cut toward the connecting portion with the arm portion 140, and the second slit portion 142 is cut outside the arm portion 140 toward the connecting portion between the arm portion 140 and the support side fixing portion 149. According to the structure, the length dimension of the arm part 140 is regulated to 3 to 5 mm, for example, by the depth of cut of the first slit part 141 and the second slit part 142.

  In the lens driving device 1 of the present embodiment, high accuracy is required for the spring constant of the arm unit 140 even in the spring member 14x. Therefore, in the present embodiment, first, in the cutting process, as shown in FIG. 7B, a notch 143 or the like is formed on the thin plate by pressing the thin plate or etching using a photolithography technique to support the thin plate. The body side fixing portion 149, the moving body side fixing portion 148, the arm portion 140, the frame 147, and the connecting plate portion 147d are formed.

  Next, in the laser trimming process, the spring constant of the arm part 140 formed by the cutting process is measured, and the spring constant is corrected by changing the shape and dimensions of the arm part 140 with a laser based on the measurement result of the spring constant. . Specifically, in any of the four cutouts 143 shown in FIG. 7B, the laser is applied to the end of the second slit portion 142 among the both ends (the first slit portion 141 and the second slit portion 142). By irradiating the spot, a partial cut is made at the connecting portion between the arm part 140 and the support-side fixing part 149 so as to extend the second slit part 142. As a result, in any of the four arm portions 140, a laser cut portion 145 is formed at the connecting portion between the arm portion 140 and the support side fixing portion 149, and the length of the arm portion 140 is cut by the laser. Stretched by the specified dimension. When cutting with such a laser, the cutting dimension is set based on the result of measuring the spring constant of the arm portion 140.

  Since the other configuration is the same as that of the spring member 14y, the description thereof will be omitted. However, the spring constant of the arm member 140 is set to an optimum value by forming the cut portion 145 by the laser in the laser trimming process. Since the correction is made, the same effect as that of the spring member 14y is obtained, for example, the accuracy of the spring constant is high.

(Other embodiments)
In the two spring members 14x and 14y, the plate thickness, the length of the arm portion 140, and the extending direction may be the same, but these configurations may be different. In the above embodiment, laser trimming is performed on all of the four arm portions 140 formed on the spring members 14x and 14y. However, laser trimming may be performed on only a part of the four arm portions 140. Further, the present invention may be applied to a spring member in which the arm part 140 is bent or bent halfway.

  Furthermore, in the above embodiment, the present invention is applied to the spring members 14x and 14y used in the lens driving device 1. However, the present invention may be applied to a spring member mounted on another device.

(A), (b) is the external view which looked at the lens drive device to which this invention is applied from diagonally upward, and an exploded perspective view, respectively. It is explanatory drawing which shows typically operation | movement of the lens drive device 1 shown in FIG. (A), (b) is a top view which shows the structure before laser trimming of one spring member used for the lens drive device to which this invention is applied, and the said spring member. (A), (b) is explanatory drawing of the laser trimming process at the time of manufacturing the spring member to which this invention is applied, and explanatory drawing of the cutting part by a laser. It is explanatory drawing of the cutting shape by the laser in the spring member to which this invention is applied. It is explanatory drawing which shows the change of the spring constant before and behind laser trimming in the spring member to which this invention is applied. (A), (b) is the top view of the other spring member used for the lens drive device to which this invention is applied, and the top view which shows the state before isolate | separating the said spring member from a flame | frame.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Lens drive device 2 Support body 3 Moving body 11 Spacer 13 Sleeve 14x, 14y Spring member 17 Magnet 18 Yoke 19 Holder 30 Drive coil 140 Arm part 141 First slit part 142 Second slit part 143 Notch 145 Laser cutting part 148 Moving body side fixing portion 149 Supporting body side fixing portion

Claims (13)

In a lens driving device having a support, a moving body including a lens, and a spring member that supports the moving body so as to be movable along the lens optical axis.
The spring member includes a support body-side fixing portion that is fixed to the support body side, a moving body-side fixing portion that is fixed to the moving body side, and a plurality of leaf springs that connect the support body-side fixing portion and the moving body-side fixing portion. Arm-shaped part,
At least one of the plurality of arm portions includes a laser cutting portion at a part of the edge portion.   2. The lens driving device according to claim 1, wherein an edge portion of the arm portion other than the cutting portion by the laser is a cutting portion by press processing or etching processing using a photolithography technique.   In the spring member, the laser cut portion is formed so as to extend a length of the arm portion by extending a notch sandwiching the arm portion on both sides. The lens drive device described in 1. The arm portion extends in the circumferential direction,
The spring member includes a first slit portion cut toward a connecting portion between the arm portion and the movable body side fixed portion inside the arm portion, and the arm portion and the support body side outside the arm portion. A second slit portion cut toward the connecting portion with the fixed portion,
The cut portion by the laser is formed so as to extend the length of the arm portion by extending the first slit portion and / or the second slit portion. Lens drive device.   In any of the plurality of arm portions, the first slit portion positioned inside the arm portion and the second slit positioned outside the arm portion formed at a position adjacent to the arm portion in the circumferential direction. The lens driving device according to claim 4, wherein the slit portion forms a notch connected in the circumferential direction.   6. The lens driving device according to claim 4, wherein the laser cut portion is formed to extend the length of the arm portion by extending the second slit portion. The movable body side fixed portion is formed in an annular frame shape in which the plurality of arm portions are connected,
The lens driving device according to claim 4, wherein the arm portion is curved along the movable body side fixed portion. In a method for manufacturing a lens driving device, comprising: a support body; a moving body including a lens; and a spring member that supports the moving body so as to be movable along the lens optical axis.
The spring member includes a support body-side fixing portion that is fixed to the support body side, a moving body-side fixing portion that is fixed to the moving body side, and a plurality of leaf springs that connect the support body-side fixing portion and the moving body-side fixing portion. Arm-shaped part,
In manufacturing the spring member,
A cutting step of cutting a thin plate to form the support side fixing portion, the moving body side fixing portion, and the arm portion;
A laser trimming step of measuring the spring constant of the arm portion formed by the cutting step, and correcting the spring constant by changing the shape and dimensions of the arm portion by a laser based on the measurement result of the spring constant;
A method for manufacturing a lens driving device.   The said cutting process WHEREIN: The said support body side fixing | fixed part, the said mobile body side fixing | fixed part, and the said arm part are formed by the press process with respect to the said thin plate, or the etching process using photolithography technique, The said arm part is formed. Method for manufacturing the lens driving device of the present invention. A spring member provided with a support body side fixing portion fixed to the support body side, a moving body side fixing portion fixed to the moving body side, and a plate spring-like arm portion connecting the support body side fixing portion and the moving body side fixing portion. Because
The arm part is provided with a laser cutting part at a part of the edge part.   11. The spring member according to claim 10, wherein an edge portion of the arm portion other than a portion cut by the laser is a portion cut by an etching process using a press process or a photolithography technique. A spring member provided with a support body side fixing portion fixed to the support body side, a moving body side fixing portion fixed to the moving body side, and a plate spring-like arm portion connecting the support body side fixing portion and the moving body side fixing portion. A manufacturing method of
A cutting step of cutting a thin plate to form the support side fixing portion, the moving body side fixing portion, and the arm portion;
A laser trimming step of measuring the spring constant of the arm portion formed by the cutting step, and correcting the spring constant by changing the shape and dimensions of the arm portion by a laser based on the measurement result of the spring constant;
The manufacturing method of the spring member characterized by performing.   The said cutting part WHEREIN: The said support body side fixing | fixed part, the said mobile body side fixing | fixed part, and the said arm part are formed by the press process with respect to the said thin plate, or the etching process using a photolithographic technique, The said arm part is formed. Of manufacturing the spring member.

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