CN102047164A - Lens drive device - Google Patents

Abstract

A lens drive device provided with an electric power supplying member capable of being easily soldered to a module board. The electric power supplying member mounted between a lower plate spring and a base and supplying electric power to a drive coil has a flexible printed board sandwiched between the lower plate spring and the base and electrically connected to a pair of lead wires of the drive coil, and also has a pair of elastic, sheet metal terminals extending downward from the flexible printed board to the module board.

Description

lens driver

technical field

The present invention relates to a lens driving device, in particular to a lens driving device for autofocus used in a portable compact camera.

Background technique

A portable compact camera is mounted on a mobile phone with a camera. A lens driving device for autofocus is used in this portable compact camera. Various autofocus lens driving devices have previously been proposed.

For example, Patent Document 1 (Japanese Unexamined Patent Application Publication No. 2006-258969) discloses a mobile phone with a camera that shortens the time required for automatic focusing. The portable phone with a camera (lens driving device) disclosed in this patent document 3 is provided with: a frame (lens frame) having a cylindrical portion on which a lens (lens frame, lens barrel) is mounted at one end; A drive coil fixed around the frame (lens frame); a yoke with a permanent magnet facing the drive coil; A pair of plate springs that displaceably support the frame (lens frame) in the optical axis direction in a state where the frame is positioned in the radial direction. By energizing the driving coil, the position of the lens (lens group) can be adjusted in the optical axis direction by utilizing the interaction between the magnetic field of the permanent magnet and the magnetic field generated by the current flowing in the driving coil. Of the pair of leaf springs, one is called an upper leaf spring (front spring), and the other is called a lower leaf spring (rear spring). The inner peripheral end portion of the upper leaf spring (front spring) is sandwiched between the upper end (tip) of the frame and the stopper, and fitted into the frame (lens frame).

The lens driving device disclosed in this Patent Document 1 further includes: an actuator and a base that are disposed outside the lower leaf spring in the optical axis direction and sandwich the lower leaf spring with the end surface of the yoke in the optical axis direction; A sheet-shaped electrode (power supply part) arranged between the lower leaf spring, the driver, and the base to supply power to the driving coil. The chip electrode has: a substantially circular annular portion (electrode portion) formed of a polyimide thin plate; and an extension portion extending radially outward from the annular portion. The extension part extends to the outside of the driver and the base through the insertion holes of the driver and the base. The extension part is connected to the module substrate and functions to supply current to the driving coil. By soldering the tips of the pair of lead wires of the drive coil to the terminal portion provided on the annular portion of the chip electrode, power can be supplied to the drive coil.

prior art literature

patent documents

Patent Document 1: Japanese Unexamined Patent Publication No. 2006-258969 (Fig. 2, Fig. 3, Fig. 7)

Contents of the invention

In the lens driving device disclosed in Patent Document 1, since the sheet electrodes are flexible, they need to be led out to the module substrate on the side of the lens driving device. Since the sheet electrodes are flexible, it is difficult to solder the protrusions of the sheet electrodes to the module substrate. In addition, there is a danger that the extended portion of the chip electrode is exposed outside the outer shape of the lens driving device.

An object of the present invention is to provide a lens driving device including a power supply member that can be easily soldered to a module substrate.

Another object of the present invention is to provide a lens driving device including a power supply member that is not exposed outside the outer shape of the lens driving device.

Another object of the present invention will become clear through further description.

If the gist of the illustrated embodiment of the present invention is described, the lens driving device has: a lens holder having a cylindrical portion for holding the lens group; a driving coil fixed to the lens holder around the cylindrical portion; The yoke of the permanent magnet opposite to the drive coil; and the yoke that is arranged on both sides of the optical axis direction of the cylindrical part of the lens holder and can support the displacement of the lens holder in the direction of the optical axis in the state where the lens holder is positioned radially. Upper leaf spring and lower leaf spring. Each of the upper leaf spring and the lower leaf spring has an inner peripheral end attached to the lens holder; and an outer peripheral end attached to the yoke. The lens driving device can adjust the position of the lens holder in the direction of the optical axis by energizing the driving coil and utilizing the interaction between the magnetic field of the permanent magnet and the magnetic field generated by the current flowing in the driving coil. The lens driving device also includes: a base, when the base is mounted with a yoke, the base and the yoke clamp the outer peripheral end of the lower leaf spring; A power supply component that supplies power to the drive coil. According to an example of the present invention, the power supply part has: a flexible printed circuit board sandwiched between the lower leaf spring and the base and electrically connected to a pair of lead-out wires of the drive coil; A pair of resilient sheet metal terminals extending to the module base plate.

In the present invention, the power supply part to the drive coil is composed of a flexible printed circuit board that is clamped between the lower leaf spring and the base and is electrically connected with a pair of lead-out wires of the drive coil; and from the flexible printed circuit board A pair of elastic sheet metal terminals extending downward to the module substrate makes it easy to solder the power supply components to the module substrate without exposing the power supply components to the outside of the lens driver.

Description of drawings

FIG. 1 is a perspective view of a lens driving device according to an embodiment of the present invention.

FIG. 2 is an exploded perspective view of the lens driving device shown in FIG. 1 .

FIG. 3 is a front sectional view of a main part of the lens driving device shown in FIG. 1 .

Detailed ways

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

A lens driving device 10 according to an embodiment of the present invention will be described with reference to FIGS. 1 to 3 . FIG. 1 is a perspective view showing a lens driving device 10 . FIG. 2 is an exploded perspective view of the lens driving device 10 . FIG. 3 is a front cross-sectional view of main parts of the lens driving device 10 .

Here, as shown in FIGS. 1 to 3 , a rectangular coordinate system (X, Y, Z) is used. In the states shown in Figures 1 to 3, in the Cartesian coordinate system (X, Y, Z), the X-axis direction is the front-back direction (depth direction), the Y-axis direction is the left-right direction (width direction), and the Z-axis direction is is the up-down direction (height direction). In addition, in the examples shown in FIGS. 1 to 3 , the up-down direction Z is the direction of the optical axis O of the lens.

However, in an actual use situation, the direction of the optical axis O, that is, the Z-axis direction becomes the front-rear direction. In other words, the upward direction of the Z axis becomes the front direction, and the downward direction of the Z axis becomes the rear direction.

The illustrated lens driving device 10 is installed in a mobile phone with an auto-focusing camera. The lens driving device 10 is used to move a lens group (lens barrel) (not shown) in the optical axis O direction. The lens driving device 10 has a base 12 disposed on the lower side (rear side) in the Z-axis direction (optical axis O direction). On the lower part (rear part) of the base 12, although not shown in the figure, an imaging element arranged on a module substrate is mounted. The imaging element captures a subject image formed by the lens group and converts it into an electrical signal. The imaging element can be constituted by, for example, a CCD (charge coupled device) type image sensor, a CMOS (complementary metal oxide semiconductor) type image sensor, or the like. Thus, a camera unit is constituted by a combination of the lens driving device 10, the module substrate, and the imaging element.

The lens driving device 10 has: a lens frame 14 having a cylindrical portion 140 for holding a lens group (lens barrel); a drive coil 16 fixed to the lens frame 14 around the cylindrical portion 140; The yoke 20 of the permanent magnet 18 facing the coil 16 , and a pair of leaf springs 22 and 24 provided on both sides of the cylindrical portion 140 of the lens holder 14 in the direction of the optical axis O. The pair of leaf springs 22 and 24 can support the displacement of the lens holder 14 in the direction of the optical axis O in a radially positioned state. Of the pair of leaf springs 22 , 24 , one leaf spring 22 is called an upper leaf spring, and the other leaf spring 24 is called a lower leaf spring.

In addition, as mentioned above, in actual use, the upward direction in the Z-axis direction (direction of the optical axis O) is the front direction, and the downward direction in the Z-axis direction (direction of the optical axis O) is the rearward direction. Therefore, the upper leaf spring 22 is also called a front spring, and the lower leaf spring 24 is also called a rear spring.

As shown in FIG. 2 , the yoke 20 has a square cylindrical shape. That is, the yoke 20 has a square cylindrical outer cylinder portion 202 and a square annular end portion 204 provided at the upper end (tip end) of the outer cylinder portion 202 .

Therefore, the drive coil 16 is also made into a substantially square cylindrical shape that matches the shape of the square cylindrical yoke 20 . The cylindrical portion 140 of the lens holder 14 has four contact portions 140 - 1 protruding radially outward at positions corresponding to the four corners of the driving coil 16 . The four corners of the drive coil 16 are bonded to the four contact portions 140-1. That is, the drive coil 16 is bonded to the four contact portions 140 - 1 of the cylindrical portion 140 .

On the other hand, the permanent magnet 18 is composed of four permanent magnet pieces 182 with a triangular cross-section arranged on the four corners of the yoke 20, and two permanent magnets with a rectangular cross-section opposite to the two faces facing the drive coil 16. Sheet 184 constitutes. That is, the permanent magnet 18 is composed of a total of six permanent magnet pieces 182 and 184 arranged on the four corners and both sides of the square cylindrical outer tube portion 202 of the yoke 20 .

The permanent magnet 18 is arranged on the inner peripheral surface of the outer cylindrical portion 202 of the yoke 20 at a distance from the drive coil 16 .

The upper leaf spring (front spring) 22 is disposed on the upper side (front side) of the lens holder 14 in the direction of the optical axis O, and the lower leaf spring (rear spring) 24 is disposed below the direction of the optical axis O in the lens holder 14. side (back side). The upper leaf spring (front spring) 22 and the lower leaf spring (rear spring) 24 have substantially the same structure.

Specifically, the upper leaf spring (front spring) 22 has an inner peripheral end 222 attached to the lens holder 14 and an outer peripheral end 224 attached to the yoke 20 . Three arm portions are provided between the inner peripheral end portion 222 and the outer peripheral end portion 224 . Each arm portion connects the inner peripheral end portion 222 and the outer peripheral end portion 224 .

Similarly, the lower leaf spring (rear spring) 24 has an inner peripheral end 242 attached to the lens holder 14 and an outer peripheral end 244 attached to the yoke 20 . Three arm portions are provided between the inner peripheral end portion 242 and the outer peripheral end portion 244 . Each arm portion connects the inner peripheral end portion 242 and the outer peripheral end portion 244 .

In addition, the inner peripheral end is also referred to as an inner ring, and the outer peripheral end is also referred to as an outer ring.

The inner peripheral end 222 of the upper leaf spring (front spring) 22 is sandwiched and fixed between the lens holder 14 and the stop piece 26 . In other words, the stopper 26 fits into the lens holder 14 so as to sandwich the inner peripheral end 222 of the upper leaf spring (front spring) 22 with the lens holder 14 . On the other hand, the outer peripheral end portion 224 of the upper leaf spring (front spring) 22 is sandwiched and fixed between the yoke 20 and the cover 28 . Furthermore, an annular plate 34 is disposed between the outer peripheral end portion 224 of the upper leaf spring (front spring) 22 and the cover 28 .

The flap 26 has functions as described below. That is, the stopper 26 has the function of closely contacting the inner peripheral end 222 of the upper leaf spring (front spring) 22 to the lens holder 14 without deviation and with high precision. Thereby, variation in VCM (Voice Coil Motor) characteristics can be improved. In addition, the stop piece 26 has a function of increasing the bonding strength of the upper leaf spring (front side spring) 22 . Accordingly, the impact resistance of the lens driving device 10 is improved. Furthermore, the stopper 26 has a function of preventing deformation of the upper leaf spring (front spring) 22 when the lens driving device 10 is dropped and impacted. This also improves the impact resistance of the lens driving device 10 . In addition, the blocking plate 26 has the function of determining the mechanical stroke of the lens driving device 10 .

On the other hand, the outer peripheral end 244 of the lower leaf spring (rear spring) 24 is fixed to the yoke 20 via the spacer 30 . In other words, the spacer 30 and the outer peripheral end portion 244 of the lower leaf spring (rear spring) 24 are sandwiched and fixed between the yoke 20 and the base 12 . The inner peripheral end 242 of the lower leaf spring (rear spring) 24 is fixed to the lower end (rear end) side of the lens holder 14 .

An internal thread 142 is cut on the inner peripheral wall of the cylindrical portion 140 of the lens holder 14 . On the other hand, although not shown in the figure, an external thread that is helically combined with the above-mentioned internal thread 142 is cut on the outer peripheral wall of the lens group (lens barrel). Thus, when the lens group (lens barrel) is mounted on the lens holder 14, the lens group (lens barrel) is screwed together by rotating the cylindrical portion 140 of the lens holder 14 around the optical axis O and screwing the lens group (lens barrel) along the optical axis O direction. , so that the lens group (lens barrel) is accommodated in the lens holder 14, and bonded to each other with an adhesive or the like.

By energizing the drive coil 16, the position of the lens holder 14 (lens group) can be adjusted in the optical axis O direction by the interaction between the magnetic field of the permanent magnet 18 and the magnetic field generated by the current flowing in the drive coil 16.

The power supply member 32 is disposed between the lower leaf spring (rear spring) 24 and the base 12 . The power supply part 32 is used to supply power to the driving coil 16 .

The power supply part 32 has: a flexible printed circuit board 322 sandwiched between the lower leaf spring 24 and the base 12 and electrically connected to a pair of lead wires 162 of the driving coil 16; A pair of flexible metal sheet terminals 324 extend to the above-mentioned module substrate.

As shown in FIG. 3 , each of the pair of sheet metal terminals 324 has an elastic contact portion 324-1 accommodated in the base 12 and having a front end portion 324-1a elastically contacting the electrode 322a of the flexible printed circuit board 322, And a rod-shaped extension part 324-2 extending from the elastic contact part 324-1 to the module substrate. The base 12 has a pair of recesses 12 a that receive and hold the elastic contact portions 324 - 1 of a pair of sheet metal terminals 324 . The base 12 has a guide 122 having a pair of through holes 122 a for the bar-shaped extensions 324 - 2 of a pair of sheet metal terminals 324 to pass through.

Furthermore, gold plating is applied to the front end portion 324-1a of the elastic contact portion 324-1, and gold plating is applied to the electrode 322a of the flexible printed circuit board 322 in contact with the front end portion 324-1a of the elastic contact portion 324-1.

In this way, since the power supply part 32 is clamped between the lower leaf spring 24 and the base 12 and electrically connected to the pair of lead wires 162 of the driving coil 16, the flexible printed circuit board 322 and the flexible printed circuit board 322 A pair of elastic sheet metal terminals 324 extending downward to the module substrate constitutes, so the power supply part 32 can be easily connected to the module substrate by soldering, and the power supply part 32 will not be more obtrusive than the shape of the lens driving device 10. The outside is exposed. Accordingly, a printed circuit board having low heat resistance can be used as the base 12 .

In the lens driving device according to the exemplary mode of the present invention described above, each of the pair of sheet metal terminals has: an elastic contact portion accommodated in the base and having a front end portion elastically in contact with an electrode of the flexible printed circuit board; The elastic contact part may extend to the bar-shaped extension part of the module substrate, and the base has: a pair of recesses for accommodating and holding the elastic contact part of a pair of sheet metal terminals; and a bar-shaped extension for penetrating the pair of sheet metal terminals A pair of through-holes at the top is also acceptable. Preferably, the front end of the elastic contact portion is plated with gold, and the electrodes of the flexible printed circuit board that are in contact with the front end of the elastic contact portion are plated with gold.

As mentioned above, although this invention was demonstrated specifically with reference to this embodiment, this invention is not limited to this embodiment. It is understood that various changes in form and details can be made by those skilled in the art without departing from the spirit and scope of the present invention defined in the claims.

This application is based on and claims the priority of Japanese Patent Application No. 2008-136289 filed on May 26, 2008, the disclosure of which is incorporated herein as a reference in its entirety.

Claims (3)

1. A lens driving device (10), comprising: a lens holder (14) having a cylindrical portion (140) for holding the lens group; A driving coil (16) fixed on the lens holder around the cylindrical portion; a yoke (20) having a permanent magnet (18) opposite the drive coil; and An upper plate spring that is provided on both sides of the cylindrical portion of the lens holder in the direction of the optical axis (O) and supports the displacement of the lens holder in the direction of the optical axis (O) while the lens holder is positioned in the radial direction. (22) and lower side leaf spring (24), Each of the above-mentioned upper leaf spring (22) and the above-mentioned lower leaf spring (24) has an inner peripheral end (222; 242) mounted on the above-mentioned lens holder (14); and mounted on the above-mentioned yoke (20) On the outer peripheral side end (224; 244), By energizing the above-mentioned driving coil (16), the interaction between the magnetic field of the above-mentioned permanent magnet (18) and the magnetic field generated by the current flowing in the above-mentioned driving coil (16) is used, so that the above-mentioned lens driving device (10) can operate in the light Adjust the position of above-mentioned lens holder (14) on the axis (O) direction, Above-mentioned lens driving device (10) also has: A base (12) for mounting the yoke (20) on the base (12), and clamping the outer peripheral side of the lower leaf spring (24) with the base (12) and the yoke (20) end (244); and a power supply member (32) disposed between the lower leaf spring (24) and the base (12) to supply power to the drive coil, Above-mentioned power supply part (32) has: A flexible printed circuit board (322) clamped between the above-mentioned lower side leaf spring (24) and the above-mentioned base (12) and electrically connected to a pair of lead-out wires (162) of the above-mentioned driving coil (16); and A pair of resilient metal sheet terminals (324) extend downward from the flexible printed circuit board to the module substrate. 2. The lens driving device according to claim 1, wherein: Each of the above-mentioned pair of sheet metal terminals (324) has a front end portion (324-1a) accommodated in the above-mentioned base (12) and having an elastic contact with the electrode (322a) of the above-mentioned flexible printed circuit board (322). an elastic contact portion (324-1); and a rod-shaped extension portion (432-2) extending from the elastic contact portion to the above-mentioned module substrate, The above-mentioned base (12) has: a pair of recesses (12a) for accommodating and holding the above-mentioned elastic contact parts of the above-mentioned pair of sheet metal terminals; hole (122a). 3. The lens driving device according to claim 2, wherein: The above-mentioned front end portion (324-1a) of the above-mentioned elastic contact portion (324-1) is gold-plated, The electrode (322a) of the flexible printed circuit board (322) that is in contact with the front end portion of the elastic contact portion is plated with gold.

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