JP2003149537A - Lens driving device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lens driving device which is small-sized and lightweight. SOLUTION: The device is equipped with a front lens 2, a front support frame 3 which supports the front lens 2, a front coil which is fitted behind the front support frame 3, a front metal piece 21 which is fitted on the inner circumferential surface of the front coil 4, a front spring 5 which is fitted behind the outer circumferential part of the front support frame 3, a rear lens 6, a rear support frame 7 which supports the rear lens 6, a rear metal piece 22 which is fitted on the outer circumferential surface of the rear coil 8, a rear spring 9 which is fitted behind the inner circumferential part of the rear support frame 7, a magnet 10, a front bearing 23 which is fitted on the outer circumferential surface of the magnet 10, a rear bearing 24 which is fitted on the inner circumferential surface of the magnet 10, and a yoke 11; and the front coil 4 is arranged in the outside gap between the magnet 10 and yoke 11 and the rear coil 8 is arrange din the internal gap between the magnet 10 and yoke 11. Then a current is applied to the front coil 4 to move the front lens 2 forward and applied to the rear coil 8 to move the rear lens 6 forward.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens driving device used in a portable compact camera for zooming a subject.

[0002]

2. Description of the Related Art As a lens driving device of this type, a device in which a stepping motor and a feed screw transmission mechanism are combined is known, and this lens driving device is shown in FIG.
As shown in FIG. 7, the lens driving device 100 transmits the rotating shaft of the stepping motor 101 to the feed screw 103 via the gear 102 to convert the rotational movement into the linear movement. A lens 105 is fixed on a nut 104 which is guided and driven on the feed screw 103. Therefore, the linear position of the lens 105 is determined according to the rotation angle of the stepping motor 101.

[0003]

However, the above-described technique requires a complicated transmission mechanism such as the stepping motor 101, the gear 102, the feed screw 103, and the nut 104, which makes the device large and the lens. There is a problem that 105 is shaken in the radial direction.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a lens driving device which is small and lightweight and which does not cause radial blur even if the lens is moved linearly.

[0005]

According to a first aspect of the present invention, there is provided a front lens, a front support frame for supporting the front lens, and a front coil mounted behind the front support frame.
A front metal piece mounted on the inner peripheral surface of the front coil,
A front spring attached to the rear of the outer peripheral portion of the front support frame,
A rear lens, a rear support frame that supports the rear lens, a rear coil that is attached to the rear of the rear support frame, a rear metal piece that is attached to the outer peripheral surface of the rear coil, and an inner rear portion of the rear support frame A rear spring mounted on the magnet, a magnet, a front bearing mounted on the outer peripheral surface of the magnet, a rear bearing mounted on the inner peripheral surface of the magnet, and a yoke. And the rear coil is arranged in the inner gap between the magnet and the yoke, and the rear coil is arranged in the inner gap between the magnet and the yoke. By applying a current to the front coil, the front lens is moved forward and a current is applied to the rear coil. Therefore, the rear lens is moved forward.

According to the first aspect of the invention, the front coil is arranged in the outer gap between the magnet and the yoke, and the rear coil is arranged in the inner gap between the magnet and the yoke. Therefore, a current is applied to the front coil. Then, the front lens can be moved forward by the action of the electromagnetic force of the outer gap, and the rear lens can be moved forward by the action of the electromagnetic force of the inner gap when a current is applied to the rear coil. As a result, the structure of the device can be made simple and small.

According to a second aspect of the present invention, in the first aspect of the invention, the moving amount of the front lens is balanced by the elastic force of the front spring and the electromagnetic force based on the amount of current applied to the front coil. The moving amount of the rear lens is determined by a balance between the elastic force of the rear spring and the electromagnetic force based on the amount of current applied to the rear coil.

According to the invention described in claim 2, claim 1
While exhibiting the same effect as the invention described in (1), the moving amount of the front lens is determined by the elastic force of the front spring and the electromagnetic force based on the amount of current applied to the front coil being balanced, The amount of movement is determined by the balance between the elastic force of the rear spring and the electromagnetic force based on the amount of current applied to the rear coil, so that each of the front lens and the rear lens can be easily moved by a desired amount. be able to. This allows the structure of the device to be more compact and less expensive.

The invention described in claim 3 is the invention according to claim 1 or 2.
In any one of the inventions described above, the front metal piece and the front bearing are brought into close contact with each other with suction force, and the rear metal piece and the rear bearing are brought into close contact with each other with suction force.

In the invention described in claim 3, claim 1
In addition to the same effect as the invention described in any one of 1 to 2, the front metal piece and the front bearing are brought into close contact with each other by suction force, and the rear metal piece and the rear bearing are brought into close contact with each other with suction force. It is possible to prevent directional blurring.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings. 1 is a sectional view showing a lens driving device according to the present invention, FIG. 2 is an exploded perspective view of the lens driving device of FIG. 1, and FIG.
FIG. 4 is a plan view of the bearing shown in FIG. 4, FIG. 4 is a plan view of the metal piece shown in FIGS. 1 and 2, FIG. 5 is an enlarged perspective view of the spring shown in FIGS. FIG. 9 is a cross-sectional view showing the operation of the lens driving device of

The lens driving device 1 includes a front lens 2, a front support frame 3, a front coil 4, a front spring 5, a front metal piece 21, a rear lens 6, a rear support frame 7, and a rear coil 8. The rear spring 9, the rear metal piece 22, the magnet 10, the front metal piece 23, the rear bearing 24, and the yoke 11 are provided, and by applying a direct current to the front coil 4, By moving the lens 2 forward and applying a direct current to the coil 8, the rear lens 6 is moved forward. In this specification, the words “front” and “rear” are used as appropriate, but this means a relative front and rear positional relationship from the camera toward the subject.

The ring-shaped front support frame 3 is an electrical insulator such as a synthetic resin, supports the front lens 2 at the center, has a front coil 4 on the rear on the outer peripheral projection, and has an outermost peripheral portion. ,
The inner peripheral portion (a) of the front spring 5 is fixed, and the front metal piece 21 is fixed to the reference angle point on the inner circumference of the front coil 4.

Similarly, the ring-shaped rear support frame 7 is an electrical insulator such as a synthetic resin, supports the rear lens 6 in the central portion, and is provided with a rear coil 8 on the rear side on the outer peripheral convex portion. The inner peripheral portion (a) of the rear spring 9 is fixed to the inner peripheral portion,
A rear metal piece 22 is fixed to a reference angle point on the outer circumference of the rear coil 8.

The ring-shaped yoke 11 has a shape composed of an outer wall 11a, an inner wall 11b and a bottom surface 11c.
The wall height of a is larger than that of the inner wall 11b, and the ring-shaped magnet 10 is fixed on the bottom surface 11c. The magnet 10 is magnetized in the radial direction, and the bearings 23 and 24 are fixed on the inner and outer peripheral surfaces of the reference angle point on the circumference.
A magnetic path is formed by 1a, the inner wall 11b, and the bottom surface 11c.

The front coil 4 includes a magnet 10 and an outer wall 1.
1a, the rear coil 8 is likewise arranged between the magnet 10 and the inner wall 11b. The outer peripheral portion (b) of the front spring 5 is fixed to the upper end of the outer wall 11a via the outer peripheral insulating ring 12, and similarly, the outer peripheral portion (b) of the rear spring 9 is connected to the inner wall via the inner peripheral insulating ring 13. It is fixed to the upper end of 11b.

3A and 3B respectively show the front bearing 23.
3 is a plan view showing a rear bearing 24, which is curved along the outer peripheral surface and the inner peripheral surface of the magnet 10, respectively, and is adhered onto a reference angle point of a ring-shaped magnet, and is made of a material such as oilless metal. It is the sliding bearing used.

FIG. 4A is a plan view showing the front metal piece 21 and FIG. 4B is a plan view showing the rear metal piece 22, respectively, along the inner peripheral surface of the front coil 5 and the outer peripheral surface of the rear coil 8. It is a curved magnetic body, and is bonded to the front coil 5 and the rear coil 8 at reference angle points on the circumference. The front and rear bearings 23, 24 are extremely thin in the radial direction, and similarly, the front and rear metal pieces 21, 22 are also extremely thin in the radial direction. As a structure, the magnet 10, the outer wall 11a, and the inner wall 11b are formed. The thickness does not affect the gap between them.

FIGS. 5 (a) and 5 (b) are perspective views showing the structures of the front spring 5 and the rear spring 9, in which (a) is a folded state and (b) is an extruded state. Shows the shape of. The front spring 5 and the rear spring 9 are divided in half, and the spring property maintains the shape of the folded (a) when no external force is applied, and is pushed out when an external force is applied (b). Transforms into the shape of.

Since the inner peripheral portion (a) of the front spring 5 is fixed to the outermost peripheral portion of the front support frame 3 and the outer peripheral portion (b) is fixed to the upper end of the outer wall 11a, when no external force is applied. The front support frame 3 is located almost in contact with the upper end of the outer wall 11a. Similarly, the inner peripheral portion (a) of the rear spring 9 is fixed to the innermost peripheral portion of the rear support frame 7, and the outer peripheral portion (b) is the inner wall 11b.
Since it is fixed to the upper end of the, when no external force is applied,
The rear support frame 7 is located almost in contact with the upper end of the inner wall 11b.

Both the winding start and the winding end of the front coil 4 are arranged on the front support frame 3 side, and the winding start is connected to one of the halves of the inner peripheral portion (a) of the front spring 5 to finish the winding. Connect to the other half. Further, at the upper end of the outer wall 11a, the front coil 4 is attached to one of the halves of the outer peripheral portion (b) of the front spring 5.
Connect the positive side of the current terminal for connection, and connect the negative side to the other half.

Due to this connection, the current applied to the front coil 4 is passed from the positive side to the front coil 4 through one outer half (b) and one inner half (a) of the front spring 5. The voltage is applied at the beginning of winding and the end of winding flows out to the minus side via the other half of the inner circumference (a) and the outer circumference (b).

Similarly, the winding start and winding end of the rear coil 8 are both arranged on the rear support frame 7 side, and the winding start is connected to one of the inner halves of the rear spring 9 (a). , Connect the end of winding to the other half. Further, at the upper end of the inner wall 11b, the positive side of the current terminal for the rear coil 8 is connected to one half of the outer peripheral portion (b) of the rear spring 9, and the negative side is connected to the other half.

Due to this connection, the current applied to the rear coil 8 passes through the outer side (b) and the inner side (a) of one of the halves of the rear spring 9 from the positive side of the rear coil 8. The voltage is applied at the beginning of winding and the end of winding flows out to the minus side via the other half of the inner circumference (a) and the outer circumference (b).

The outer peripheral insulating ring 12 and the inner peripheral insulating ring 13 are respectively provided on the outer peripheral portion (b) of the front spring 5 and the outer wall 1.
Between the upper ends of 1a and the outer peripheral portion (b) of the rear spring 9 and the inner wall 1
A spring and a yoke, which are electric conductors, are interposed between the upper ends of 1b.
Insulates between 1

Next, the operation of this embodiment will be described based on the above-mentioned configuration. To assemble the lens driving device 1, first, the front lens 2 is assembled into the front support frame 3, and the front spring 5 and the outer peripheral insulating ring 12 are fixed (adhered) in this order. Subsequently, the front coil 4 is fixed (adhered) to the convex portion of the front support frame 3, and then the front metal piece 21 is adhered to the reference angle point on the inner peripheral surface of the front coil 4, so that the winding start and winding end are respectively performed. , The inner peripheral portion (a) is connected to one side and the other side.

Similarly, the rear lens 6 is incorporated into the rear support frame 7, and the rear spring 9 and the inner peripheral insulating ring 13 are respectively
Stick (bond) in this order. Continuing, rear support frame 7
The rear coil 8 is fixed (adhered) to the convex portion of, and then the rear metal piece 22 is adhered to the reference angle point on the outer peripheral surface of the rear coil 8 so that the winding start and the winding end are respectively the inner peripheral portion (a).
Connect to one and the other.

The front bearing 23 and the rear bearing 24 are adhered to each other so as to face each other on the circumferential surface of the magnet 10 to form a reference angle point. Pre-position on the bottom surface 11c of the yoke 11,
The magnet 10 with the bearings 23 and 24 attached is fixed (adhered). While inserting the rear coil 8 into the gap between the magnet 10 and the inner wall 11b, the inner insulating ring 13 is fixed (adhered) to the upper end of the inner wall 11b, and one and the other outer peripheral portions (b) are respectively attached to the rear coil 8. Connect the positive and negative sides of the current terminal for use.

Similarly, while inserting the front coil 4 into the gap between the magnet 10 and the outer wall 11a, the outer peripheral insulating ring 12 is fixed (adhered) to the upper end of the outer wall 11a so that one and the other of the outer peripheral portion (b) are connected. Each is connected to the plus side and minus side of the front coil 4 current terminal.

The positive and negative connections for the rear coil 8 are led out to the outside by lead wires along the outer peripheral side of the inner wall 11b, and the positive and negative connections for the front coil 4 are lead wires along the outer peripheral side of the outer wall 11a. It has a structure in which a DC current is applied to each of them by drawing them out to the outside.

Since the metal pieces 21 and 22 are magnetic bodies, an attractive force acts between the metal pieces 21 and 22 and the front and rear bearings 23 and 24 are in close contact with each other. That is, the front support frame 3
The rear support frame 7 and the rear support frame 7 are supported and positioned by the front spring 5 and the rear spring 9, respectively, but there is play in the radial direction. Due to the close contact effect by the attraction force, the movement of the magnet 10 according to the reference angle point can be realized, and the radial blurring can be prevented.

FIG. 6 shows a front coil 4 and a rear coil 8.
FIG. 3 is a cross-sectional view when a DC current is applied to the lens driving device 1 to operate the lens driving device 1 in a zoom state.

When a current is applied to the front coil 4, a forward (upward in FIG. 4) electromagnetic force acts on the front lens 2, but the elastic force of the front spring 5 moves backward (FIG. 4) in proportion to the displacement. Then, work downward). Therefore, the position of the front lens 2, that is, the moving distance to the front, is a point where the electromagnetic force and the elastic force are balanced.

As a result, the amount of movement of the front lens 2 can be determined by the amount of current applied to the front coil 4. Similarly, the amount of current applied to the rear coil 8 can determine the amount of movement of the rear lens 6.

That is, the amount of movement of each of the front lens 2 and the rear lens 6 can be determined by the amount of each current applied to the front coil 4 and the rear coil 8. CCD) together with the action of the fixed lens 14 located inside the camera (below)
A subject image can be zoomed and focused on the image plane 15 such as by.

Here, the front support frame 3 includes the front metal piece 21.
And the front bearing 23 are in close contact with each other, and the rear support frame 7 moves forward with the rear metal piece 24 and the rear bearing 24 in close contact, so that the bearings 23, 24 are in close contact with each other. It is possible to minimize the blurring in the radial direction.

If a pulsed current is applied to the front coil 4 and the rear coil 8, the sliding friction between the metal pieces 21 and 22 and the bearings 23 and 24 is not affected, and
A smooth forward movement can be achieved while maintaining a close contact with a stable friction coefficient.

In this way, 2 is supplied to the lens driving device 1.
Only by controlling one current amount, the movement amount of each of the front lens 2 and the rear lens 6 can be controlled to zoom the image. Further, if the applied current is zero, no zooming occurs, so a DC current is required only during zooming, power consumption can be saved, and support due to external factors can be provided by the suction force acting on the metal pieces 21 and 22. The displacement of the frames 3 and 7 can be prevented.

The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the invention. For example, in FIGS. 1, 2 and 6, the front metal piece 21 is bonded to the outer peripheral surface of the front coil 4, and the front bearing 23 is fixed to the inner peripheral surface of the outer wall 11a of the yoke.
If the rear metal piece 22 is adhered to the inner peripheral surface of the rear coil 8 by suction adhesion, and the rear bearing 24 is fixed to the outer peripheral surface of the inner wall 11b of the yoke and suction adhered, the outer wall 1 respectively.
The movement of 1a and the inner wall 11b according to the reference angle point can be realized, and the radial deviation can be minimized.

Further, in FIGS. 1, 2 and 6, the metal pieces 21, 22 and the bearing 2 are made to face each other at the same reference angle point in the circumferential direction.
3, 24 are arranged, but not limited to this, for example, the rear metal piece 22 and the rear bearing 24 are the front metal piece 2
Even if they are arranged at an angle of 180 ° opposite to the arrangement angle of 1 and the front bearing 23, the same effect can be obtained.

Further, in FIG. 3, the front spring 5 and the rear spring 9 have a half-split structure, and they are used for the plus side and the minus side energizing paths, respectively. A sex lead wire may be used.

[0039]

According to the first aspect of the invention, the front lens can be moved forward by applying a current to the front coil, and the rear lens can be moved forward by applying a current to the rear coil. Therefore, the structure of the device can be made simple and small.

According to the second aspect of the invention, the same effect as that of the first aspect of the invention can be obtained, and by controlling the amount of current to be applied, the amounts of movement of the front lens and the rear lens can be controlled. Therefore, the structure of the device can be made more compact and inexpensive.

The invention described in claim 3 has the same effect as that of the invention described in any one of claims 1 and 2, and since the lens can be moved in a close contact state by the suction force, the lens blurring can occur. Can be blocked.

[Brief description of drawings]

FIG. 1 is a sectional view showing a lens driving device according to the present invention.

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

FIG. 3 is a plan view of the bearing shown in FIGS.

FIG. 4 is a plan view of the metal piece shown in FIGS.

FIG. 5 is an enlarged perspective view of the spring shown in FIGS.

6 is a cross-sectional view showing the operation of the lens driving device of FIG.

FIG. 7 is a perspective view showing a conventional lens driving device.

[Explanation of symbols]

1 Lens drive 2 front lens 3 Front support frame 4 front coil 5 front spring 6 rear lens 7 Rear support frame 8 rear coil 9 rear spring 10 magnets 11 York 21 front metal piece 22 Rear metal piece 23 Front bearing 24 Rear bearing

Claims (3)

[Claims] 1. A front lens, a front support frame for supporting the front lens, a front coil attached to the rear of the front support frame, a front metal piece attached to an inner peripheral surface of the front coil, and a front support. A front spring attached to the rear of the outer periphery of the frame, a rear lens, a rear support frame supporting the rear lens, a rear coil attached to the rear of the rear support frame, and an outer peripheral surface of the rear coil. The rear metal piece, the rear spring attached to the rear of the inner peripheral portion of the rear support frame, the magnet, the front bearing attached to the outer peripheral surface of the magnet, and the rear bearing attached to the inner peripheral surface of the magnet. A bearing and a yoke are provided, the front coil is arranged in an outer gap between the magnet and the yoke, and the rear coil is arranged in an inner gap between the magnet and the yoke.
A lens driving device characterized in that a front lens is moved forward by applying a current to a front coil, and a rear lens is moved forward by applying a current to a rear coil. 2. The amount of movement of the front lens is determined by balancing the elastic force of the front spring and the electromagnetic force based on the amount of current applied to the front coil, and the amount of movement of the rear lens is
The lens driving device according to claim 1, wherein the elastic force of the rear spring and the electromagnetic force based on the amount of current applied to the rear coil are determined by a balance. 3. The lens driving device according to claim 1, wherein the front metal piece and the front bearing are brought into close contact with each other by suction force, and the rear metal piece and the rear bearing are brought into close contact with each other with suction force.