JP2008268405A - Voice coil type lens drive device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lens drive device achieving excellent focusing of a lens by maintaining the relative positions of a coil of a movable unit and a fixed magnet in a normal state and stabilizing the relative position of the movable unit to an entire device. <P>SOLUTION: The voice coil type lens drive device for performing the focusing of the lens comprises a base 1, conduction springs 2 and 2 arranged on the base 1, a metallic yoke 6 arranged on the conduction spring 2, the magnet 5 attached inside the yoke 6, the movable unit M1 inserted in the yoke 6 while it is opposed to the magnet 5, a leaf spring 7 arranged on the yoke 6, and a cover frame 8 coupled with the base 1 while it is superposed and arranged on the leaf spring 7. The lower end projection 8c of the cover frame 8 is fit in the hollow part 1f of the base 1 so as to achieve integration, and also a notch 6d formed on the yoke 6 is fit to a projection 1e of the base 1. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a voice coil type lens driving device that adjusts the focus of a lens by a repulsive magnetic force generated between a magnetic field generated by energizing a coil and a fixed magnet facing the coil.

  2. Description of the Related Art Conventionally, in a voice coil type lens driving apparatus that adjusts the focus of a lens by a repulsive magnetic force generated between a magnetic field generated by energizing a coil and a fixed magnet facing the coil, the relative movement between the coil of the movable unit and the fixed magnet For example, Patent Document 1 discloses a method for maintaining the position in a normal state and stabilizing the relative position of the movable unit with respect to the entire apparatus.

As shown in FIG. 15, the metal rear cover 114 to which the fixed magnet M is attached is fitted to the fixed frame 110, and the support cover 140 and the front cover 150 are coupled to the fixed frame 110. It is.
Registered utility model No. 3126325 (see FIG. 6)

  As described above, in the form disclosed in Patent Document 1, the metal rear cover 114 to which the fixed magnet M is attached is fitted to the fixed frame 110, and the support cover 140 and the front cover 150 are attached to the fixed frame 110. The whole lens driving device is configured by combining them.

  However, the above apparatus is not particularly defective in terms of function, but improvement of the following problems is desired.

  In other words, when there is a processing error or assembly error between the above components, or there is a case where play occurs in the fitting gap due to slack or the like that occurs during long-term use. It becomes difficult to stabilize the relative position.

  As a result, the play that occurs in the fitting gaps between the component parts can destabilize the position of the lens mounted inside the movable unit depending on the posture of the entire device to be used, and can exhibit the predetermined performance of the lens. There is a risk of disappearing.

  The present invention solves such a problem, maintains the relative position between the coil of the movable unit and the fixed magnet in a normal state, and stabilizes the relative position of the movable unit with respect to the entire apparatus. An object of the present invention is to provide a voice coil type lens driving device that performs focus adjustment.

In order to solve the above problem, the means of the present invention is a voice that adjusts the focus of a lens by a repulsive magnetic force generated between a magnetic field generated by energizing a coil of a movable unit equipped with a lens and a fixed magnet facing the coil. In the coil type lens driving device,
A lower base, a pair of conduction springs arranged on the base, a metallic yoke arranged on the conduction springs, a magnet mounted in the yoke, and a movable inserted into the yoke while facing the magnet A unit, a leaf spring disposed on the yoke, and an upper cover frame coupled to the base while being disposed on the leaf spring,
The base is a plate-shaped main body molded from synthetic resin, four struts projecting upward at the four corners of the main body, a lens opening formed in the center of the main body, and an attachment formed on the inner periphery of the strut Having a dimple as a reference,
The yoke has a quadrangular bottomed cylindrical box body in which one surface in the optical axis direction is released and a lens opening is formed in the center of the other bottom surface, and a bent portion that rises downward from the four corners of the bottom surface. And incisions formed at the tip of the box opposite to the bent portion at the four corners of the box,
The cover frame has a plate-like main body formed of a synthetic resin, four pillars standing at the four corners of the main body, a lens opening formed at the center of the main body, and a protrusion provided at the tip of the four pillars. And
The tip projection of the cover frame is fitted and integrated with the recess of the base, and the notch formed in the yoke is fitted to the projection of the base.

  In this case, the base is a plate-shaped main body formed of synthetic resin, four pillars projecting upward at the four corners of the main body, a lens opening formed in the center of the main body, and a lip of the lens opening. A guide cylinder standing up around, a groove formed on the outer side of the guide cylinder, a protrusion formed on the inner base of the support column, and a recess serving as a reference for attachment to the inner periphery of the support column above the protrusion. It is preferable that it is comprised from these.

  Similarly, the movable unit has a coil base formed of a cylindrical body having a lens mounting portion at the center and a rectangular outer shape, and projections formed on the outer four surfaces of the cylindrical body, and a coil wound around each of the projections. It is preferable to comprise.

According to the first aspect of the present invention, the voice coil type adjusts the focus of the lens by the repulsive magnetic force generated between the magnetic field generated by energizing the coil of the movable unit equipped with the lens and the fixed magnet facing the coil. In the lens driving device of
A base, a conductive spring disposed on the base, a metallic yoke disposed on the conductive spring, a magnet mounted in the yoke, a movable unit inserted in the yoke while facing the magnet, and a yoke And a cover frame coupled to the base while being stacked on the leaf spring,
The base is a plate-shaped main body molded from synthetic resin, four struts projecting upward at the four corners of the main body, a lens opening formed in the center of the main body, and an attachment formed on the inner periphery of the strut Having a dimple as a reference,
The yoke has a quadrangular bottomed cylindrical box body in which one surface in the optical axis direction is released and a lens opening is formed in the center of the other bottom surface, and a bent portion that rises downward from the four corners of the bottom surface. And incisions formed at the tip of the box opposite to the bent portion at the four corners of the box,
The cover frame has a plate-like main body formed of a synthetic resin, four pillars standing at the four corners of the main body, a lens opening formed at the center of the main body, and a protrusion provided at the tip of the four pillars. And
Since the lower end protrusion of the cover frame is fitted and integrated with the recess of the base and the notch formed in the yoke is fitted to the protrusion of the base, the relative position between the coil of the movable unit and the fixed magnet is adjusted. By maintaining the normal state and stabilizing the relative position of the movable unit with respect to the entire apparatus, it is possible to perform favorable lens focus adjustment.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. As shown in FIG. 1, a lens driving device using a voice coil motor according to the present invention includes a leaf spring 7, a yoke 6, a magnet 5, a coil base 4, a washer 3, a conduction spring 2, and a cover frame 8. The base 1 is constructed by sequentially stacking. The assembly exploded perspective view of FIG. 1 shows a state in which the upper cover frame 8 is originally placed on the lower side, and the lower components are sequentially assembled on the cover frame 8 as can be seen from FIG. .

  As shown in FIG. 2, the base 1 is formed of synthetic resin in a plate shape in which the main body forms a quadrangle, and four support pillars 1a projecting upward are formed at the four corners of the main body. A hole serving as a lens opening 1b is formed in the center of the main body, and a cylindrical guide tube 1c stands up around the edge of the hole.

  A cutout 1g is formed in one piece of the main body.

  Further, as described in FIGS. 8, 13, and 14, arcs are formed on the outer side of the base of the cylindrical protrusion 1c, and slightly deep grooves 1d are formed at four equal intervals. . Further, a semicircular protrusion 1e is formed on the inner base portion of the support 1a, and a semicircular recess 1f is formed above the protrusion 1e and bites into the inner periphery of the support 1a.

The conduction spring 2 is composed of a thin plate made of a material having conductivity such as phosphor bronze and having excellent spring characteristics, and is composed of a pair of leaf springs arranged symmetrically opposite each other. As shown in FIGS. 11 (A) and 11 (B), this is formed by an outer U-shaped spring body 2b and a semicircular thin spring piece 2a formed inside the spring body 2b. A support piece 2c is formed at one end of the outer spring body 2b by bending it into an L shape. Similarly, two concave corners 2d chamfered at 45 degrees are formed at two outer corners of the spring body 2b. .

Further, the inner spring piece 2a and the outer spring body 2b are connected by a thin spring wire body. The spring wire body has one end connected to the inner spring piece 2a and a horizontal curved portion 2e that repeats a U-turn, and the outer spring body. 2b and a longitudinal curve portion 2f that repeats a U-turn by connecting the other end. In this case, the curved portion 2e that repeats the U-turn by contacting one end with the inner spring piece 2a and the curved portion 2f that repeats the U-turn by coupling the other end to the outer spring body intersect, for example, at 90 degrees. . That is, the other vertical curve portion 2f is connected to the one horizontal curve portion 2e with a displacement of 90 degrees.

Further, both end portions 2g of the inner semicircular spring piece 2a are provided with a groove so that a terminal of a coil C, which will be described later, can be attached, and are formed in a hook shape. A groove-shaped guide portion 2h is formed for attachment to the coil base 4 to be performed.

 In the above embodiment, the conduction spring 2 is divided into two parts, but it can also be formed integrally. In that case, one conduction terminal may be pulled out from the leaf spring 7.

The washer 3 is composed of a thin film formed of an electrically insulating material, and is formed of a rectangular frame 3a as shown in FIGS. 1 and 2, and is formed by small arcs at four outer corners of the frame 3a. A formed recess 3b is provided.

As shown in FIGS. 9 and 10, the coil base 4 has a cylindrical body having a rectangular outer shape and a lens opening 4a formed at the center of the cylindrical body. The whole is formed and processed with a synthetic resin. Two projections 4d are formed on each outer surface 4c of the outer periphery of the rectangular cylinder, and the projections 4d are formed so that the base is thin and the outside is thick. For example, an upwardly tapered surface is formed on the outer surface of the protrusion 4d to increase the outer diameter.

One coil C is wound around the outer periphery of these protrusions 4d, that is, around two protrusions 4d formed on each outer surface 4c of the cylinder.

In this case, when a predetermined number of times of winding is finished at one place, the cylindrical body is rotated 90 degrees and the coil C is wound on the next outer surface 4c.

In this way, the respective protrusions 4d of the four outer surfaces 4c are sequentially wound, and the terminals are attached to the support pieces 2g of the inner spring side 2a of the conduction spring 2 by soldering or the like in the attaching step described later.

The lens mounting screw 4b portion of the coil base 4 has a cylinder 4f standing upright in a cylindrical shape, and small cylinders 4g formed at four locations on the outer periphery at equal intervals. Furthermore, deep and long rectangular holes 4h are formed in parallel with the optical axis direction so as to be in contact with the outer peripheral side of the cylinder 4f erected in the cylindrical shape at the four corners of the cylindrical body of the coil base 4.

On the other hand, as shown in FIG. 12, on the upper surface of the cylindrical body opposite to the above in the optical axis direction of the coil base 4, in other words, on the lower surface side of the coil base 4 shown in FIG. Subsequently, arc-shaped protruding pieces 4i that are partially extended and stand up are formed at four positions at equal intervals, and a flat surface 4j is formed outside the protruding pieces 4i. Small guide pins 4k are erected on the four corners of the cylindrical body outside the flat surface 4i. The arc-shaped protruding piece 4i is fitted into the arc-shaped groove 1d of the base 1 when assembled.

The magnet 5 is magnetized as a permanent magnet, and is composed of four pieces of magnets as shown in FIGS. 1 and 4 and is attached to the inner walls of the four sides of the following yoke 6 formed of a magnetic material of a thin metal plate. Is fixed.

As shown in FIGS. 1 and 2, the yoke 6 has one lower surface in the optical axis direction (the lower surface in FIG. 2) released and the other bottom surface (the upper surface in FIG. 2) in the center. A rectangular bottomed cylindrical box having a lens opening 6a formed thereon, bent portions 6b erected downward from the four corners of the bottom surface, and opposite to the bent portions 6b at the four corners of the box. And a notch 6d formed at the tip (upper end in FIG. 1).

  The fixed magnets 5 are attached to the insides of the four sides of the box, and the movable unit is disposed inside the box so that the magnet C faces the magnet 5.

  In the above case, the corner of the box in the yoke 6 has a surface 6c chamfered at an angle of 45 degrees with respect to the side wall having four sides, and the bent portion 6b extends from the bottom along the inside of the surface 6c. Similarly, a square cut 6d is formed at the release end of the surface 6c. This square notch 6d is elaborately formed and is fitted to the semicircular protrusion 1e formed on the base 1, and serves as a reference for an attachment position for exerting the performance of the entire apparatus.

The leaf spring 7 is composed of a thin plate made of a material having conductivity such as phosphor bronze and having excellent spring characteristics like the conduction spring 2, and is composed of a single part as shown in FIG. The frame is composed of a thin spring frame 7a having a square edge, a thin spring ring 7b having a round inner edge, and a linear body having a spring property that connects the spring frame 7a and the spring ring 7b.

Four corners of the rectangular outer spring frame 7a are formed by inclined surfaces 7c chamfered at 45 degrees so as to serve as guides for attachment, and attachment guides are provided at four outer peripheral portions of the inner spring ring 6b. The semicircular depressions 7d are formed at equal intervals.

As in the case of the conductive spring 2, the connecting wire is connected to the inner spring ring 7b with one end and a horizontal curved portion 7e that repeats a U-turn, and the outer spring frame 7a with the other end. Thus, a vertical curved portion 6f that repeats the U-turn is formed. Also in this case, similarly to the conductive spring 2 described above, the curved portion 6e and the curved portion 6f are displaced at an angle that intersects at 90 degrees.

As shown in FIGS. 1 and 2, the cover frame 8 includes a plate-like main body 8d formed of a synthetic resin in a quadrangular shape, and four columns 8a that stand downward in FIG. 2 at the four corners of the main body 8d. And a lens opening 8b formed at the center of the main body 8d. The support column 8a is formed as a right-angled isosceles triangular column having an inclined inner angle of 45 degrees on the inside. A semicircular protrusion 8c serving as a coupling portion is provided on the tips (upper ends in FIG. 1) of the four columns 8a.

Next, the order of assembling these components will be described in detail. Basically, as shown in FIG. 1, a plate spring 7, a yoke 6, a magnet 5, a coil base 4, a washer 3, a conduction spring 2 and a base 1 are sequentially stacked in a cover frame 8.

First, the slopes 7c at the respective corners of the spring 7 are attached so as to be in contact with the slopes of the columns 8a of the cover frame 8. The yoke 6 is inserted into the lens 6a so that the lens opening 6a is at the bottom, and the inclined surface 6c at the corner is aligned with the inclined surface of the column 8a. Accordingly, the leaf spring 7 is sandwiched between the cover frame 8 and the yoke 6.

Next, the four pieces of magnets 5 are attached and fixed to the inner periphery of each side wall of the yoke 6. In this case, the magnet 5 is magnetized as a permanent magnet, and the yoke 6 is also a magnetic material.

Subsequently, the movable unit M1 is configured by the coil base 4 and the coil C wound around each of the four outer peripheral surfaces of the cylindrical body of the coil base 4, and this movable unit M1 is passed through the inside of the magnet 5 to the yoke 6. The four coils C are attached so as to face the fixed magnet 5. In this case, the square holes 4 h formed at the four corners of the coil base 4 are inserted into the bent portions 6 b inside the yoke 6. That is, the movable unit M1 is attached using the bent portion 6b inside the yoke 6 as a guide, and simultaneously moves along the bent portion 6b during operation.

By adopting such an attachment method, the movable unit M1 in which the coil C is wound around the coil base 4 as described above has a relatively improved dimensional accuracy, so that the gap between the coil C and the magnet 5 is reduced. A stable distance can be secured between the two while taking a small size. Accordingly, the coil C can be energized to generate a magnetic field, and the repulsive force with the magnet 5 can be made stable and strong.

In this case, when the movable unit M1 is attached using the bent portion 6b as a guide, the cylindrical portion 4f formed on the lower side (upper side in FIG. 2) of the coil base 4 faces the inner spring ring 6b of the leaf spring 7. At the same time, the cylinder 4g is fitted into the recess 7d of the leaf spring 7.

Next, the washer 3 and the two conduction springs 2 are sequentially placed on the flat surface 4j formed on the coil base 4. The washer 3 is placed so that the recesses 3b at the four corners face the inner side of the support column 8a of the cover frame 8, and the two conduction springs 2 have four arc-shaped guides 2h on the inner side of the coil base 4. The guide pin 4k is fitted and placed.

The terminals of the coil C are soldered to the inner ends 2g of the two conduction springs 2, respectively. Since the washer 3 is formed of an insulating material, electrical insulation is ensured so that the coil C and the conduction spring 2 do not inadvertently come into contact with each other and become electrically conductive. The work described above can be completed in advance in the state of the movable unit M1.

Finally, when the base 1 is attached, the entire unit is completed. In attaching, the support 1a of the base 1 and the support 8a of the cover frame 8 are brought together. Then, a semicircular protrusion 8 c formed at the front end of the support frame 8 is fitted into a recess 1 f formed in the support 1 a of the base 1.

Further, at this time, the semicircular protrusion 1e formed on the inner side of the column 1a of the base 1 has a rectangular cut 6d formed on the slope of the corner of the yoke 6, the recess 3b of the washer 3, and the conduction spring 2. It fits into the recess 2d. Further, the surface 6 c chamfered at the corner of the yoke 6 is fitted into the inside of the support column 8 a of the cover frame 8 to be regulated in position, and is aligned with the base 1.

Accordingly, the movable unit M1 is controlled along with the cover frame 8 and the base 1 along the yoke 6 while maintaining the positional accuracy, and a highly accurate and smooth operation can be secured. That is, the semicircular protrusion 1e formed on the inner side of the support column 1a of the base 1 is fitted into a square notch 6d formed on the slope of the corner of the yoke 6, and the inner side of the support column 8a of the cover frame 8 The position is regulated by fitting to the base 1 and the positioning with the base 1 is also performed. When confirmation of the final assembled state is completed, an adhesive is applied to the joint between the cover frame 8 and the base 1, or a joint tape is stretched on the outer peripheral portion of the joint to complete the coupling between the two. Is completed.

Therefore, since the parts that require positional accuracy are directly connected to each other and attached, the play based on each part error is reduced, the relative position of the movable unit with respect to the entire apparatus is maintained at the reference position, and high precision is achieved. The configuration can be realized.

In the coupled state, the L-shaped support piece 2 c of the conduction spring 2 is configured to protrude from the notch 1 g of the base 1.

Hereinafter, an operation method of the lens driving device in the embodiment configured as described above will be described in detail. By inputting an output signal of a lens control circuit (not shown but known) to the L-shaped support piece 2c of the conduction spring 2, a current is supplied to the coil C, and the magnetic field according to the left hand rule of framing is changed to the coil C. appear.

Due to the magnetic field generated in the coil C, a repulsive force acts between the magnetic field of the magnet 5 attached to the yoke 6 so as to face the coil C, and the movable unit M1 moves by a distance corresponding to the output signal of the lens control circuit. To do. Thereby, the focal position of a predetermined lens can be controlled. That is, the subject image light beam incident from the cover frame 8 side can be appropriately formed on the light receiving element behind the base 1.

In addition, this invention is not limited to the said embodiment, It can implement by changing suitably within the range of the technical idea of this invention.

1 is a perspective view of a voice coil type lens driving apparatus according to an embodiment of the present invention. It is the disassembled perspective view which looked at the arrangement | positioning of FIG. 1 from the reverse direction. (A) is a plan view of a voice coil type lens driving device according to an embodiment of the present invention, (B) is a right side view, and (C) is a rear view. It is an AA line crossing top view in FIG. It is a BB line vertical side view in FIG. It is CC sectional view taken on the line in FIG. (A) is a perspective view of a spring, (B) is a partial enlarged perspective view of a spring. It is a partial expanded sectional view of FIG. (A) is a top view of a coil base, (B) is a right view. It is a perspective view of the coil base which attached a part of coil. (A) is a conduction spring perspective view, (B) is a partially enlarged perspective view. It is a perspective view which shows the assembly | attachment state of a base and a coil base. It is a perspective view of the state which assembled | attached the coil base to the base. It is a cross-sectional top view of a base. It is a disassembled perspective view of the conventional voice coil type lens drive device.

Explanation of symbols

1 Base 2 Conducting Spring 3 Washer 4 Coil Base 5 Magnet 6 Yoke 7 Leaf Spring 8 Cover Frame M1 Movable Unit C Coil

Claims (3)

In a voice coil type lens driving device that adjusts the focus of a lens by a repulsive magnetic force generated between a magnetic field generated by energizing a coil of a movable unit equipped with a lens and a fixed magnet facing the coil,
A base, a conductive spring disposed on the base, a metallic yoke disposed on the conductive spring, a magnet mounted in the yoke, a movable unit inserted in the yoke while facing the magnet, and a yoke And a cover frame coupled to the base while being stacked on the leaf spring,
The base is a plate-shaped main body molded from synthetic resin, four struts projecting upward at the four corners of the main body, a lens opening formed in the center of the main body, and an attachment formed on the inner periphery of the strut Having a dimple as a reference,
The yoke has a quadrangular bottomed cylindrical box body in which one surface in the optical axis direction is released and a lens opening is formed in the center of the other bottom surface, and a bent portion that rises downward from the four corners of the bottom surface. And incisions formed at the tip of the box opposite to the bent portion at the four corners of the box,
The cover frame has a plate-like main body formed of a synthetic resin, four pillars standing at the four corners of the main body, a lens opening formed at the center of the main body, and a protrusion provided at the tip of the four pillars. And
A voice coil type lens driving device characterized in that a tip projection of the cover frame is fitted and integrated with a recess of the base and the notch formed in the yoke is fitted to the projection of the base. The base is a plate-shaped main body molded from synthetic resin, four pillars projecting upward at the four corners of the main body, a lens opening formed in the center of the main body, and standing around the edge of the lens opening A guide cylinder, a groove formed on the outer side of the guide cylinder, a protrusion formed on the inner base of the support column, and a recess that is connected to the upper periphery of the support column and serves as an attachment reference that bites into the inner periphery of the support column. The voice coil type lens driving device according to claim 1. The movable unit is composed of a coil base formed of a cylindrical body having a lens mounting portion at the center and a quadrilateral outer shape, and projections formed on the outer four surfaces of the cylindrical body, and coils wound around the projections. The voice coil type lens driving device according to claim 1 or 2.

Images