JP2007316395A - Lens drive device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lens drive device which is easy to assemble. <P>SOLUTION: In the lens drive device 1, the outer circumference part 9b of a front spring 9 is fixed between a base 5 and a yoke 3. The inner circumference part 9a of the front spring 9 is disposed in contact with the front end of the lens support 7. A rear spring 11 is disposed between the base 5 and the lens support 7. Thus, the lens support 7 is supported on the base 5 so as to freely move forward or backward. Additionally, the lens support 7 is moved forward or backward along the direction of the optical axis of the lens by magnetic force generated by supplying power to a coil 15 disposed in the lens support 7. In such a lens drive device, engaging parts 10, which engage with the front spring 9, are formed at the front end of the lens support 7. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an autofocus lens driving device used for a small camera.

  In Patent Document 1, annular springs are arranged on the front side and the rear side of a lens support body of a small camera, the inner peripheral side portion of the front spring is disposed in contact with the front end of the lens support body, and the outer peripheral side portion is arranged. It is disclosed to fix by sandwiching between a yoke and a frame.

JP 2005-128405 A

  However, in the manufacturing process of the conventional lens driving device, the rear spring, the lens support with the coil fixed, the yoke with the magnet, the front spring and the frame (housing) are arranged in this order on the base (rear housing). The front spring and the frame are sandwiched by tweezers and are simultaneously disposed on the front side of the lens support, and the frame is assembled and fixed to the base. After assembly, the front end of the lens support and the inner peripheral side of the front spring were fixed with an adhesive.

  The front spring and frame are clamped together and assembled together because the front spring is attached to the front end of the lens support when the frame is assembled after the front spring is placed on the front end of the lens support. The front spring will become unstable if it is just placed, and the position of the front support will shift with respect to the front end (tip) of the lens support, or when the outer periphery of the front spring is pressed against the yoke by the frame, Since the front spring may spring off due to the urging force, when assembling the front spring, the frame and the front spring are overlapped at a predetermined position with tweezers and assembled at the same time.

  Therefore, in the manufacturing process of the lens driving device, it is necessary to hold the front spring and the frame at the same time and to assemble with the overlapping position of the front spring and the frame at a predetermined position. In particular, since the lens driving device for a small camera has an outer diameter of about 1 mm, it is difficult to hold the two parts in a predetermined positional relationship, and it is difficult to assemble the parts.

  Therefore, an object of the present invention is to provide a lens driving device that can be easily assembled.

  The invention according to claim 1 is an annular yoke, a magnet disposed inside the yoke, a lens support disposed on the inner peripheral side of the yoke and having a coil fixed to the outer periphery, and an annular front spring. A rear spring, a base disposed on the rear side of the yoke, and a frame disposed on the front side of the yoke, and an outer peripheral side portion of the front spring is fixed between the base and the yoke. The inner peripheral side of the lens is placed in contact with the front end of the lens support, and the rear spring is provided between the base and the lens support so that the lens support can be moved back and forth with respect to the base. The lens driving device moves the lens support back and forth along the optical axis direction of the lens by electromagnetic force generated by energizing the coil, and an engagement portion with a front spring is provided at the front end of the lens support. Tako The features.

  According to a second aspect of the present invention, in the first aspect of the present invention, the engaging portion is a plurality of protrusions arranged at intervals in the circumferential direction on the front end of the lens support, The periphery is provided with a recessed portion that is recessed toward the outer peripheral side, and the engaging portion engages with the recessed portion.

  According to a third aspect of the present invention, in the first aspect of the present invention, the front spring is arranged such that the inner peripheral side portion projects from the outer peripheral side portion to the front side in the optical axis direction, and the elastic force of the spring causes the lens to move. The supporting member is always biased toward the rear side.

  According to the first aspect of the present invention, the lens driving device is assembled on the base by a rear spring (the rear spring may be fixed to the lens support in advance) and a lens support in which a coil is fixed. The body, the yoke with the magnet fixed, the front spring, and the frame are stacked and assembled in this order. The front spring has an inner peripheral side portion placed on the front side end of the lens support, and an inner peripheral side portion of the front spring is engaged with the engaging portion of the lens support. As a result, the front spring engages with the lens support while the front spring is mounted on the lens support, so that the front spring can be prevented from being displaced or dropped with respect to the lens support and can be stably mounted. it can.

  Since the frame and the front spring are separately assembled sequentially, each positioning can be performed individually, and the assembly is easy. In particular, it is not necessary to align two parts as in the prior art and sandwich them with tweezers at the same time.

  In addition, you may adhere and fix the engaging part of a lens support body and a front side spring with an adhesive agent after the assembly | attachment of each component.

  According to the second aspect of the present invention, the function and effect of the first aspect can be obtained, and the engaging portion is a protruding portion. Therefore, the engaging portion can be easily formed on the lens support by molding, for example. Since the front spring is only formed with a recess, the front spring can be easily molded during the manufacturing process.

  In addition, the springs can be easily positioned by arranging the engaging portions at intervals in the circumferential direction.

  According to the third aspect of the present invention, the effect of the first aspect can be obtained, and the outer peripheral side portion is placed on the yoke while the inner peripheral side portion of the front spring is placed on the tip of the lens support. The front spring is likely to become unstable during assembly because it needs to be pressed to the side, but even in such a case, the front spring can be engaged with the front end of the lens support so that it can be held stably. It is possible to easily suppress the outer peripheral side portion with a frame against this.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is an exploded perspective view of a lens driving device according to an embodiment of the present invention, FIG. 2 is a perspective view showing an assembled state of a lens support and a front spring, and FIG. FIG. 4 is a perspective view of the lens driving device showing a previous assembled state, and FIG. 4 is a longitudinal sectional view of the lens driving device.

  A lens driving device 1 according to the present embodiment is a lens driving device for an autofocus camera incorporated in a mobile phone. The lens driving device 1 includes an annular yoke 3, a lens support 7, an annular front spring 9, a rear spring 11, a base 5 disposed on the rear side of the yoke 3, and a front side of the yoke. And an insulator (spacer) 17 is disposed between the yoke 3 and the rear spring 11.

  The yoke 3 has an outer periphery that is a quadrangle in plan view, an inner periphery that is a circular shape in plan view, a substantially U-shaped cross section, and a magnet 13 that is fixed inside the U shape.

  The base 5 has an outer wall 5 a located on the outer peripheral surface of the yoke 3 and a base portion 5 b located on the rear side of the yoke 3 (rear side in the optical axis direction of the lens). The outer peripheral side portion 11b of the rear spring 11 is placed.

  The lens support 7 has a substantially cylindrical shape. A lens (not shown) is attached to the inner periphery of the lens support 7 so that the inner periphery of the yoke 3 can be moved in the optical axis direction. A coil 15 is fixed to the outer peripheral side portion of the lens support 7 and the coil 15 enters the inside of the yoke 3 so as to move through a U-shaped gap of the yoke 3.

  An engagement portion 10 with the front spring 9 is provided at the front end (tip) 7 a of the lens support 7. In the present embodiment, the engaging portions 10 are protrusions protruding toward the front side, and four engaging portions 10 are provided at equal intervals in the circumferential direction of the lens support 7.

  The front spring 9 is an annular leaf spring, and is provided with an inner peripheral side portion 9a and an outer peripheral side portion 9b. The inner peripheral side portion 9a is attached to the lens support 7, and the outer peripheral side portion 9b is connected to the yoke 3. It is sandwiched and fixed between the frame 6. In the inner peripheral side portion 9a of the front spring 9, four concave portions 9c are formed on the inner peripheral edge at equal intervals. The concave portion 9c is formed with an engaging portion 10 of the lens support 7 in the concave portion 9c. Is designed to fit. The size of the recess 9c is slightly larger than that of the engaging portion 10 to such an extent that the rattling occurs when the engaging portion 10 of the lens support 7 is inserted.

  Although the rear spring 11 is an annular leaf spring as a whole, in the present embodiment, it is composed of a first side portion 12 and a second side portion 14 that are divided into left and right sides. The outer peripheral side portion 11 b is sandwiched between the base 5 and the yoke 3 via an insulator (spacer) 17, and the insulator 17 aims at electrical insulation between the rear spring 11 and the yoke 3. Yes. The inner peripheral side portion 11 a is in contact with the rear end of the lens support 7.

  In the present embodiment, a terminal 19 is formed on one side 12 constituting the rear spring 11, a terminal 20 is formed on the other side 14, and each terminal 19, 20 is connected to a power supply terminal. It has come to be. The one side portion 12 and the other side portion 14 are electrically connected to the coil 15 by soldering or the like, respectively, and the coil 15 is energized from the rear spring 11.

  The front spring 9 and the rear spring 11 are provided with arm portions 25 between the inner peripheral side portions 9a and 11a and the outer peripheral side portions 9b and 11b, respectively, and each arm portion 25 is connected to the inner peripheral side portion 9a. 11a and the outer peripheral side portions 9b and 11b are connected with elasticity.

  The front spring 9 and the rear spring 11 are flat in a natural state before assembly (a state before the frame 6 is assembled) (see FIG. 2), but at least the front spring 9 is not illustrated after the assembly. As shown in FIG. 4, it is attached in a state of being elastically deformed so that the inner peripheral side portion 9a is positioned forward of the outer peripheral side portion 9b. As a result, the inner peripheral side portion 9a constantly urges the lens support 7 with the urging force directed toward the base 5 by the restoring force (urging force) of the spring.

  The frame 6 is disposed on the front side of the lens support 7, holds the outer peripheral side portion 9 b of the front spring 6 with the yoke 3, and is fitted and fixed to the base 5 to fix the base 5 and the frame 6. The casing is formed with.

Next, assembly, operation, and effect of the lens driving device 1 according to the present invention will be described.
In the assembly, the coil 15 is fixed to the outer periphery of the lens support 7, and the inner peripheral side portions 11 a and 11 a of the one side portion 12 of the rear spring 11 and the other side portion 14 are attached to the rear end portion of the lens support 7. Attach and solder the one side portion 12 and the other side portion 14 of the rear spring to the coil 15. Inside the yoke 3, magnets 13 are fixed to the respective corners of a square in plan view (preliminary process).

  The lens support 7 is disposed on the base 5 together with the coil 15 and the rear spring 11, and the outer peripheral side portion 11b of the rear spring 11 is placed on the base portion 5b of the base 5 (first step).

  Next, an insulator (spacer) 17 is placed on the outer peripheral side portion 11b of the rear spring 11 (second step), and the yoke 3 with the magnet 13 fixed thereon is placed on the insulator 17 and the yoke The coil 15 is disposed inside the U-shaped cross section (third step).

  Subsequently, the front spring 9 is disposed at the front end 7 a of the lens support 7. The front spring 9 inserts the engaging portion 10 provided at the tip of the lens support 7 into the concave portion 9c formed on the inner peripheral edge of the inner peripheral side portion 9a, and engages the concave portion 9c with each engaging portion 10. (4th process). Since the front end 7a of the lens support 7 protrudes forward from the yoke, the outer peripheral side of the front spring 9 is obtained when the inner peripheral side 9a of the front spring 9 is engaged with the engaging portion 10. The part 9b is in a state of floating from the yoke 3 (a state in which a gap is left).

  Next, the lens support 7 and the front spring 9 are finely adjusted so that their centers are aligned, and the engaging portion 10 of the lens support and the recess 9c of the front spring 9 are fixed with an adhesive. Work is easy because it is flat and can be bonded.

  Thereafter, the frame 6 is arranged so as to cover the front spring 9 and is fitted and fixed to the outer wall 5 a of the base 5. When fitting the frame 6 to the base 5, the outer peripheral side portion 9 b of the front spring 9 is pressed against the front surface of the yoke 3 against the urging force of the front spring 9, and the outer peripheral side portion 9 b is pressed between the yoke 3 and the frame. (5th process).

  Finally, the base 5 and the frame 6 are fixed with an adhesive.

  According to the present embodiment, the lens driving device 1 is manufactured in the order of the first to fifth steps described above, and the lens support 7 to which the base 5, the rear spring 11 and the coil 15 are fixed. Since the yoke 3, the front spring 9, and the frame 6 to which the magnet 13 is fixed are stacked one by one in this order, the assembly can be simplified.

  When the front spring 9 is placed on the front end 7 a of the lens support 7, the front spring 9 engages the inner peripheral side portion 9 a with the engagement portion 10 of the front end 7 a of the lens support 7, thereby supporting the lens support. 7 and fixed with an adhesive, the front spring 9 can be prevented from being displaced and dropped before the frame 6 is assembled, and can be stably placed.

  Since the engaging portion 10 provided on the lens support 7 is a protruding portion, it can be easily formed integrally when the lens support 7 is molded, and only the recess 9c is formed in the front spring 9. Therefore, it can be formed at the same time as the punching of the front spring 9 or the like, and the manufacturing is easy.

  Since the engaging portions 10 are arranged at intervals in the circumferential direction, not only can the engaging portions 10 be engaged and held with the front spring 9 but also the front spring 9 can be positioned.

  When the inner spring side 9a of the front spring 9 is assembled in a state of being displaced with respect to the outer peripheral side part 9b so as to always urge the lens support 7, the front spring 9 tends to become unstable. Since the side portion 9a is held by engagement, even when the outer peripheral side portion 9b is held by the frame 6 against the urging force of the front side spring 9, misalignment hardly occurs.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the present invention.

  For example, the rear spring 11 is not limited to being divided into two parts, one side part 12 and the other side part 14, but is integrated, and the front spring 9 and the rear spring 11 are respectively soldered to the coil 15. You may make it electrically connect and electrically energize.

  The shape and dimensions of the engagement portion 10 are not particularly limited, and for example, the tip (front end) may be tapered to facilitate engagement during assembly, or the front side may be curved. Further, the number of the engaging portions 10 may be any number, for example, three.

  The insulator (spacer) 17 is not limited to being separated from the yoke 3 and the rear spring 11, but an insulating layer is formed on the base side surface of the yoke 3 or the yoke side surface of the rear spring 11, or an insulating tape is applied. It may be.

It is a disassembled perspective view of the lens drive device concerning an embodiment of the invention. It is a perspective view which extracts and shows the assembly state of a lens support and a front side spring. It is a perspective view of a lens drive device which shows a state before attaching a frame. It is a longitudinal cross-sectional view of a lens drive device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Lens drive device 3 Yoke 5 Base 6 Frame 7 Lens support body 9 Front side spring 9a Inner peripheral side part 9b Outer peripheral side part 9c Recessed part 10 Engagement part 11 Rear side spring 11a Inner peripheral side part 11b Outer peripheral side part 13 Magnet 15 Coil 25 arms

Claims (3)

An annular yoke, a magnet disposed inside the yoke, a lens support disposed on the inner peripheral side of the yoke and having a coil fixed to the outer periphery, an annular front spring, a rear spring, and the rear of the yoke A base disposed on the side and a frame disposed on the front side of the yoke, the outer peripheral side portion of the front spring is fixed between the base and the yoke, and the inner peripheral side portion of the front spring is a lens support. The rear spring is provided between the base and the lens support, and supports the lens support so that it can move back and forth with respect to the base. A lens driving device that moves the lens support back and forth along the optical axis direction of the lens,
A lens driving device characterized in that an engaging portion with a front spring is provided at a front end of the lens support.   The engaging portions are a plurality of projecting portions arranged at intervals in the circumferential direction at the front end of the lens support, and a concave portion recessed toward the outer peripheral side is provided on the inner peripheral edge of the front spring. The lens driving device according to claim 1, wherein the joint portion engages with the recess portion. The front spring is characterized in that the inner peripheral side portion is arranged so as to protrude forward in the optical axis direction from the outer peripheral side portion, and the lens support is always biased toward the rear side by the elastic force of the spring. The lens driving device according to claim 1.

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