KR20070045084A - Lens driving apparatus - Google Patents

Abstract

According to the present invention, a lens driving device capable of retaining the lens at a predetermined position in the optical axis direction while reducing power consumption and at the same time hardly causing shaking or movement in the lens holder due to external impact, and having an excellent impact resistance will be.

The lens drive device 1 of the present invention comprises a lens 15, 16, a lens holder 3, 5 holding the lens 15, 16, and a guide member for guiding movement of the lens holder 3, 5; (13), the guide part 33 provided in the lens holders 3 and 5, the coil 23, and the magnet 19 provided in accordance with the moving direction of the lens holders 3 and 5, The coil 23 is energized to move the lens in the optical axis direction, and the lens holders 3 and 5 are provided with a magnetic body 27 for position retention, and the magnetic body 27 is attracted to the magnetic force of the magnet 19. When the guided portion 33 and the guide member 13 are pressed against each other and the lens holders 3 and 5 stop, the lens is subjected to frictional force between the guided portion 33 and the guide member 13. Holders 3 and 5 are held in a constant position.

Description

Lens drive device {LENS DRIVING APPARATUS}

1 is a vertical sectional view of a lens driving apparatus according to a first embodiment.

Fig. 2 is a cross sectional view of the lens drive device according to the first embodiment, in which the drawing taken out by a dashed-dotted line shows a state where the guide member is in contact with the inner circumferential surface of the guide portion.

3 is a perspective view taken along the line A-A of the lens driving device shown in FIG. 2;

4 is a perspective view showing the lens holder of the lens driving device shown in FIG.

Fig. 5 is a cross sectional view of a lens drive device according to a second embodiment.

FIG. 6 is a perspective view taken along the line B-B of the lens driving device shown in FIG. 5; FIG.

Fig. 7 is a cross sectional view of a lens drive device according to a third embodiment.

FIG. 8 is a perspective view taken along the line C-C of the lens driving device shown in FIG. 7; FIG.

* Explanation of symbols for main parts of the drawings

1: Lens drive device 3: First lens holder (lens holder)

5: second lens holder (lens holder) 13: guide member

15: Lens for optical zoom 16: Lens for focus

17: York 19: Magnet

23: coil 25a: one side wall portion

25b: other side wall portion 25c: intermediate wall portion

27: magnetic substance (positional magnetic substance) 33: guided portion

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a lens driving apparatus for driving a lens for use in a portable compact camera or the like incorporated in a digital camera, a cellular phone, or the like, and more particularly to a lens driving apparatus capable of moving a lens linearly by an electromagnetic force.

BACKGROUND ART In general, a lens driving apparatus for driving a lens linearly is known by an electric force caused by a current flowing through a coil and a magnetic field formed by a magnet. For example, Japanese Patent Laid-Open No. 2002-23037 discloses a lens driving apparatus for magnetically driving a lens used in a camera or the like.

However, in the prior art described in the above-mentioned patent publication, when the lens is driven in the optical axis direction to reach a certain position, in order to retain the lens at that position, it is necessary to continuously flow a current through the coil. There was a problem that power consumption was wasted. Further, for example, when a camera shakes or impacts when carrying a camera, shakes or movements are likely to occur in the holder of the lens, and a lens driving device excellent in impact resistance is desired.

An object of the present invention is to obtain a lens drive device having excellent impact resistance, while being able to hold a lens at a predetermined position in the optical axis direction while reducing power consumption, and less likely to cause shake or movement in the lens holder due to external impact. do.

In order to solve the above problems, the invention described in claim 1 includes a lens, a lens holder holding a lens, a guide member for guiding movement of the lens holder, a guide portion provided in the lens holder, And a coil provided in the lens holder and a magnet provided in accordance with the moving direction of the lens holder, the lens driving device for energizing the coil and moving the lens in the optical axis direction, the lens holder having a magnetic body for position holding, The magnetic body for position holding is attracted by the magnetic force of the magnet, so that the guided portion and the guide member are press-contacted, and when the lens holder stops, the lens holder is held in a fixed position by the frictional force between the guided portion and the guide member. It is characterized by.

In the invention described in claim 2, in the invention described in claim 1, the yoke is formed of one side wall portion and the other side wall portion that are provided in parallel along the moving direction of the lens holder, and one side wall portion and the other side wall portion. The intermediate wall part provided in between is provided, The magnet is provided in the side wall part of one side wall part, and the other side wall part, each magnet is arrange | positioned toward the same magnetic pole in the middle wall part, and the coil is It is formed in a ring shape, and it arrange | positions between the one side wall part and the other side wall part by inserting the inner peripheral side of a ring part into an intermediate wall part.

In the invention described in claim 3, in the invention described in claim 1, the guide portion has a polygonal cross section, the guide member has an arc-shaped cross section, and at least two points on the outer circumferential surface of the guide member are guide portions. It is characterized in that the contact with the inner peripheral surface.

In the invention described in claim 4, in the invention described in claim 1, the magnetic body for position holding is provided between the coil and the lens holder.

In the invention described in claim 5, in the invention described in claim 4, the magnetic body for position holding is a thin plate shape.

Best Mode for Carrying Out the Invention

EMBODIMENT OF THE INVENTION Below, embodiment of this invention is described in detail, referring an accompanying drawing. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a longitudinal sectional view of a lens drive device according to a first embodiment, and Fig. 2 is a cross sectional view of a lens drive device according to a first embodiment. The drawing taken out by a dashed-dotted line shows the guide member abutting against the inner peripheral surface of the guide portion. FIG. 3 is a perspective view of the lens driving device shown in FIG. 2 taken along the line AA, and FIG. 4 is a perspective view showing the lens holder of the lens driving device shown in FIG.

The lens drive device 1 according to the first embodiment is an autofocus camera with an optical zoom which is incorporated into a cellular phone. The lens driving apparatus 1 includes a first driving mechanism 7 for driving a first lens holder (lens holder) 3 and a second driving mechanism 9 for driving a second lens holder (lens holder) 5. ).

The structure of the 1st drive mechanism 7 is demonstrated. In addition, since the first drive mechanism 7 and the second drive mechanism 9 have almost the same configuration, the same reference numerals are used for parts of the second drive mechanism 9 that exhibit the same effects as the first drive mechanism 7. Omit the description of that part by appending.

The first drive mechanism 7 is composed of a yoke 17, a magnet 19, and a coil 23. The yoke 17 is fixed to the box 11, and the coil 23 is attached to the first lens holder 3. The first lens holder 3 and the second lens holder 5 are moved in the optical axis direction with respect to the yoke 17.

The yoke 17 has a substantially spherical cross section and closes the magnetic field, and has one side wall portion 25a and the other side wall portion 25b provided in substantially parallel to the moving directions of the lens holders 3 and 5. And an intermediate wall portion 25c provided between one side wall portion 25a and the other side wall portion 25b, and each of the wall portions 25a, 25b, and 25c is provided in substantially parallel with each other. One magnet 19a is attached to the surface facing the middle wall portion 25c of the one side wall portion 25a, and the other magnet (on the surface facing the middle wall portion 25c is attached to the other sidewall portion 25b. 19b) is attached. Moreover, the closed wall part 25d is provided in the both ends of the optical-axis direction of each wall part 25a, 25b, 25c, and it is hard to produce the leakage of magnetic flux.

The magnets 19a and 19b on one side and the middle wall portion 25c are respectively N poles and the opposite poles are S poles, and N → is moved from the middle wall portion 25c toward one side wall portion 25a. A magnetic field in the S direction is formed, and a magnetic field in the N → S direction is formed from the middle wall portion 25c toward the other side wall portion 25b.

The coil 23 has a rectangular cylinder shape, a cross section is annular, and an intermediate wall portion 25c is inserted into the inner circumferential side of the annulus.

Next, the configuration of the first lens holder 3 will be described. In addition, since the first lens holder 3 and the second lens holder 5 have almost the same configuration, the same reference numerals are used for parts of the second lens holder 5 that exhibit the same effects as the first lens holder 3. Omit the description of that part by appending.

The first lens holder 3 is made of resin, and includes a lens aperture hole 29 to which the zoom lens (lens) 15 is attached, a coil attachment surface 31 to which the coil 23 is attached, and a guide. The guide portion 33 into which the member 13 is inserted, the wall insertion hole 35 through which the middle wall portion 25c of the yoke 17 is inserted, and the guide member 13 of the second lens holder 5 are hooked. The engaging part 37 is provided. The first lens holder 3 is free to slide in the optical axis direction by the guide member 13.

The coil attachment surface 31 is provided in substantially parallel with each wall part 25a, 25b, 25c of the yoke 17. As shown in FIG. A thin plate-like magnetic body (position-holding magnetic body) 27 is attached to the coil attachment surface 31, and the magnetic body 27 is sandwiched between the outer circumferential side of the coil 23 and the coil attachment surface 31. It is. The magnetic body 27 is in the magnetic field range of one magnet 19a, and the magnetic body 27 is attracted to the magnetic force of one magnet 19a, and the guide part 33 is forced down to the outer circumferential surface of the guide member 13. ) As the magnetic body 27, a stainless alloy having a thickness of about 50 µm and a size of about 3 mm x 5 mm is used.

The guide portion 33 has a substantially rectangular cross section, the guide member 13 has a circular cross section, and two points 13a and 13b of the outer circumferential surface of the guide member 13 have an inner circumferential surface of the guide portion 33. Abuts on

The second lens holder 5 holds the focus lens (lens) 16 in the lens opening hole 29, and the slide is freely provided in the optical axis direction by the guide member 13. In addition, the zoom lens 15 and the focus lens 16 have the same optical axis.

Next, the effect of the lens driving apparatus 1 according to the first embodiment will be described. When photographing a subject with a mobile phone camera equipped with the lens driving apparatus 1, when optical zoom is used, a current is sent to the coil 23 to drive the first driving mechanism 7. By driving of the first driving mechanism 7, the first lens holder 3 attracts the magnetic material 27 to the magnetic force of one magnet 19a, and the guide portion 33 is pressed against the outer circumferential surface of the guide member 13. It moves from the solid line position shown in FIG. 1 to the position shown by the dashed-two dotted line. When the first lens holder 3 reaches this position, energization to the coil 23 is stopped.

When the first lens holder 3 stops, the first lens holder 3 is subjected to friction between the guide portion 33 and the guide member 13 generated by the magnetic body 27 being pulled by the magnetic force of one magnet 19a. Is held at that position.

Also, the second lens holder 5 in which the focus lens 16 is assembled is also moved from the solid line position shown in FIG. 1 to the position indicated by the two-dot chain line by the same driving operation as the first lens holder 3. do.

In the first embodiment, when the lens holders 3 and 5 stop, the lens is subjected to friction between the guide portion 33 and the guide member 13 generated by the magnetic body 27 being pulled by the magnetic force of one magnet 19a. Since the holders 3 and 5 are held, it is not necessary to continuously flow current to the coil 23 in order to hold the lens holders 3 and 5, and the waste of power consumption can be reduced.

In the non-energization of the coil 23, the magnetic body 27 is attracted by the magnetic force of one magnet 19a, and the lens holders 3 and 5 are brought into friction by the friction force between the guide portion 33 and the guide member 13. In this case, even when a shake or an impact occurs, for example, when the camera is carried, shakes and movements are unlikely to occur in the lens holders 3 and 5, and the shock resistance is excellent.

In addition, the coil 23 inserted into the intermediate wall portion 25c is wound in a ring shape around the intermediate wall portion 25c, and between one side wall portion 25a of the yoke 17 and the intermediate wall portion 25c. Currents reverse to each other flow in the coil portion between the first magnetic field formed and the second magnetic field formed between the other side wall portion 25b and the intermediate wall portion 25c. Therefore, according to the Fleming's left-hand law, the propulsion force in the same direction acts on the coil 23 in the first magnetic field and the second magnetic field, respectively, so that the sum of the two propulsion forces is obtained to obtain the sum propulsion force, thereby providing the first propulsion force with a high propulsion force. The lens holder 3 and the second lens holder 5 may be moved.

Since the lens holders 3 and 5 can be moved with such a high propulsion force, even if the suction force on one magnet 19a is increased by increasing the size of the magnetic body 27 or the like, the lens holders 3 and 5 are not moved. Necessary propulsion force can be secured, and as a result, the holding force of the lens holders 3 and 5 at a fixed position when the energization to the coil 23 is stopped by a large suction force can be enlarged.

Since two points on the outer circumferential surface of the guide member 13 abut against the inner circumferential surface of the guided portion 33, movement of the lens holders 3 and 5 in the lateral direction can be prevented as compared with the case where the two points of the guide member 13 are abutted. Shake and movement become harder to (3, 5).

Since at least two points of the outer circumferential surface of the guide member 13 abut against the inner circumferential surface of the guided portion 33, the friction force between the guided portion 33 and the guide member 13 can be reduced, and the lens holders 3, 5 Can be made small.

Since the magnetic body 27 is provided between the outer circumferential side of the coil 23 and the coil attachment surface 31, the magnetic body 27 is simple and does not require an attachment part for attaching the magnetic body 27. Note that a space (space) to which is attached is not required, so that space can be saved, and the lens driving apparatus 1 can be miniaturized.

Since the magnetic body 27 is thin plate-shaped, processing is easy, and by changing the size of the plate, it is possible to freely change the size of the suction force attracted to the magnetic force of the magnet. Moreover, since the stainless steel alloy is used for the magnetic body 27, the magnitude | size of the suction force attracted by the magnetic force of a magnet can be changed freely by changing the iron content of an alloy. Therefore, it is possible to easily adjust the frictional force generated between the guide members 13 when the lens holders 3 and 5 are moved, and to easily adjust the moving speeds of the lens holders 3 and 5. .

Next, although 2nd Embodiment is described, in the following description, the part which shows the effect similar to 1st Embodiment mentioned above is attached | subjected with the same code | symbol, and detailed description of the part is abbreviate | omitted, In the following description The difference from 1st Embodiment mentioned above is mainly demonstrated. 5 is a cross sectional view of the lens drive device according to the second embodiment, and FIG. 6 is a perspective view taken along the line B-B of the lens drive device shown in FIG. 5.

2nd Embodiment shows the autofocus lens drive apparatus 1, and the guide part 33 which the guide member 13 penetrates is formed in two places of the lens holder 5 which holds a lens for focusing. The straight line connecting each guide portion 33 is substantially parallel to the magnet 19. Moreover, the guide part 33 has a circular cross section. The coil 23 attached to the coil attaching surface 31 of the lens holder 5 has a substantially rectangular tube shape and a longitudinal cross section is annular. And the magnetic body 27 is arrange | positioned in the inner peripheral position of a ring.

Moreover, the yoke 17 is arrange | positioned in the part which cut | disconnected one side surface of the box 11, and the magnet 19 is arrange | positioned at the inner peripheral side of the yoke 17. As shown in FIG. The magnet 19 is comprised from one magnet 19a arrange | positioned at the one end side in the optical axis direction, and the other magnet 19b arrange | positioned at the other end side of the optical axis direction, and the one magnet 19a ), The inner side (coil side) is the N pole, and the outer side (the yoke side) is the S pole. The other magnet 19b has the inner side (coil side) as the S pole and the outer side (the yoke side) as the N pole.

In the first embodiment, the magnetic body 27 is disposed at the inner circumferential position of the ring of the coil 23 on the coil attaching surface 31, so that between the coil attaching surface 31 and the magnet 19. The magnetic body 27 can be arrange | positioned using a space, and the thickness of the magnetic body 27 and the distance between the magnetic body 17 and the magnet 19 can be changed freely.

Since the two guide parts 33 are provided to be substantially parallel to the magnet 19, the guide parts 33 are guided by the suction force of the magnet 19, even if the guide parts 33 have a circular cross section. The lens holder 5 can be stably retained when pressed against the outer circumferential surface thereof.

Next, a third embodiment will be described. 7 is a cross-sectional view of the lens drive device according to the third embodiment, and FIG. 8 is a perspective view taken along the line C-C of the lens drive device shown in FIG. 7.

In the third embodiment, the longitudinal cross-shaped yoke 17 is disposed on one side surface of the box 11, the magnet 19 is arranged inside the outer yoke 17b, and the cross section is annular. The inner circumferential side of the coil 23 is inserted into the inner yoke 17a. Moreover, the annular magnetic body 27 is arrange | positioned along the inner peripheral surface of the coil 23. As shown in FIG.

In the second embodiment, since the magnetic body 27 is arranged in an annular shape along the inner circumferential surface of the coil 23, the area of the magnetic body 27 can be large, and the suction force attracted to the magnet 19 is reduced. I can make it big.

In addition, this invention is not limited to embodiment mentioned above, Needless to say that it can implement in various ways in the range which does not deviate from the summary.

In the above-described first embodiment, the guide portion is referred to as a cross section, but the cross section is not limited to this, and the cross section may be triangular or hexagonal.

The lens drive device 1 is not limited to a camera related to a cellular phone, but may be used for a digital camera.

According to the invention as set forth in claim 1, when the movement of the lens holder stops, the magnet is held by the magnetic force of the magnet and the lens holder is held by the friction force generated between the guide portion and the guide member. There is no need to continuously flow current to the coil to retain it, and the waste of power consumption can be reduced.

In the case of non-energization of the coil, the position retaining magnetic material is attracted by the magnetic force of the magnet and holds the lens holder with the friction force generated between the guided portion and the guide member. Even in this case, the lens holder is less likely to shake or move, and is excellent in impact resistance.

In addition, when the lens holder is energized by moving the coil, the lens holder moves with a driving force larger than the friction force between the guide portion and the guide member.

According to the invention described in claim 2, the first magnetic field formed between the side wall portion and the intermediate wall portion of the yoke, the other side wall portion and the intermediate wall portion, Currents in opposite directions flow through the coil portion between the second magnetic field formed between the two and the second magnetic field. Therefore, according to Fleming's left-hand rule, the propulsion force in the same direction is applied to the coil in the first magnetic field and the second magnetic field, respectively, so that the lens holder can be moved with a high propulsion force by the sum of the two propulsion forces. have.

In this way, the lens holder can be moved with a high propulsion force. Therefore, even if the size of the magnetic body is increased and the force (suction force) attracted to the magnet is increased, the propulsion force necessary for the movement of the lens holder can be sufficiently secured. By the suction force, the holding force of the lens holder when the energization to the coil is stopped can be increased.

According to the invention described in claim 3, the same effect as the invention described in claim 1 is achieved, and at least two points of the outer circumferential surface of the guide member are in contact with the inner circumferential surface of the guided portion, so that it is in contact with one point. The lens holder can be stably held.

Since at least two points of the outer circumferential surface of the guide member are in contact with the inner circumferential surface of the guided portion, the frictional force between the guided portion and the guide member can be reduced, and the amount of energization of the coil at the start of the lens holder can be reduced. .

According to the invention described in claim 4, the same effect as in the invention described in claim 1 is provided, and a position retaining magnetic body is provided between the coil and the lens holder, so that an attachment portion for attaching the magnetic material is not required. As a result, the configuration is simple, and a space for attaching the magnetic material is not required, and the space can be saved.

According to the invention set forth in claim 5, the magnetic body for position holding exhibits the same effect as the invention set forth in claim 4, and is easy to process because it is a thin plate shape. The suction force attracted can be easily changed.

Claims (5)

A lens, a lens holder holding the lens, a guide member for guiding the movement of the lens holder, a guide portion provided in the lens holder, a coil provided in the lens holder, and a magnet installed in accordance with the moving direction of the lens holder. And a lens holder having a position holding magnetic body, and the position holding magnetic body is attracted to the magnetic force of the magnet, and the guide portion and the guide member are press-contacted. And the lens holder is held at a predetermined position by the frictional force between the guided member and the guide member when the lens holder is stopped. The yoke is provided with one side wall portion and the other side wall portion that are provided in parallel in accordance with the moving direction of the lens holder, and an intermediate wall portion provided between the one side wall portion and the other side wall portion. The magnet is provided on the side of the middle wall and the other side wall part, and each magnet is arranged toward the same magnetic pole on the side of the middle wall, and the coil is formed in a ring shape. A lens drive device which is inserted between one side wall portion and another side wall portion through insertion. The lens according to claim 1, wherein the guide portion has a polygonal cross section, the guide member has an arc-shaped cross section, and at least two points of the outer circumferential surface of the guide member abut on the inner circumferential surface of the guide portion. Drive system. The lens drive device according to claim 1, wherein the position retaining magnetic body is provided between the coil and the lens holder. The lens drive device according to claim 4, wherein the position retaining magnetic body has a thin plate shape.

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