JP2005234089A - Lens drive device - Google Patents

Abstract

Provided is a lens driving device that is low in driving loss, excellent in responsiveness and mobility, and suitable for mounting in a small camera.
The lens driving device includes a first yoke 7 having a U-shaped cylindrical shape and a cylindrical shape having a U-shaped cross section disposed substantially concentrically with the first yoke 7 outside the first yoke 7. A second yoke 12 having a shape, a base 2 on which the first and second yokes 7 and 12 are mounted, and magnets 6 and 11 disposed inside the U-shapes of the first and second yokes 7 and 12, respectively. And the coils 4 and 9, the first lens support 5 disposed on the inner peripheral side of the first yoke 7 and having the coil 4 fixed to the outer periphery, and the coils disposed on the inner peripheral side of the second yoke 12 and on the outer periphery. The first and second lens supports 5 and 10 move linearly in the optical axis direction of the lens by electromagnetic force generated by energizing the coils 4 and 9. .
[Selection] Figure 1

Description

  The present invention relates to a lens driving device for driving a zoom lens and an autofocus lens used in a portable small camera or the like built in a digital camera or a mobile phone.

  In general, a lens driving device that can perform both automatic focusing (autofocus) and change in magnification by using a zoom lens and a focus lens is conventionally known. In such a lens driving device, the lens is usually moved in the optical axis direction by converting a rotational motion using a ball screw or the like into a linear motion (see, for example, Patent Document 1).

JP 7-140523 A

  By the way, in a lens driving device used for a portable small camera, it is required to efficiently move the lens by a desired amount in the optical axis direction in a narrow space.

  However, when the conventional structure for moving the lens in the optical axis direction by converting the rotational motion using a ball screw or the like into a linear motion is used for a portable small camera, the thrust direction and the lens moving direction are the same. Therefore, there is a possibility that the drive loss increases, and accordingly, the moving speed of the lens becomes slow or the response becomes dull.

  The present invention has been made paying attention to the above-mentioned circumstances, and its object is to provide a lens driving device that has low driving loss, excellent response and mobility, and is suitable for mounting on a small camera. There is to do.

  The invention according to claim 1 is a first yoke having a U-shaped cylindrical shape and a cylindrical shape having a U-shaped cross-section disposed substantially concentrically with the first yoke outside the first yoke. Two yokes, a base to which the first and second yokes are mounted, a magnet and a coil disposed inside each of the first and second yokes, and an inner peripheral side of the first yoke; A first lens support having a coil fixed to the outer periphery, and a second lens support disposed on the inner peripheral side of the second yoke and having a coil fixed to the outer periphery. The first and second lens supports are: Further, it is characterized in that it moves linearly in the optical axis direction of the lens by electromagnetic force generated by energizing the coil.

  According to a second aspect of the present invention, in the first aspect of the invention, the first lens support is slid in the optical axis direction by frictional engagement with the first yoke, and the second lens support is The second yoke is characterized by sliding in the optical axis direction by frictional engagement with the second yoke.

  The invention according to claim 3 is the invention according to claim 2, wherein the first and second yokes have an inner peripheral wall and an outer peripheral wall arranged substantially concentrically with each other. A plurality of legs are formed at predetermined intervals along the direction, and these legs are in sliding contact with the inner surfaces of the first and second lens supports.

  According to a fourth aspect of the present invention, in the third aspect of the invention, the first and second lens supports include an inner peripheral wall and an outer peripheral wall, and an inner peripheral wall and an outer peripheral wall, which are arranged substantially concentrically with each other. A partition wall that is connected to form a plurality of partitioned spaces between the inner peripheral wall and the outer peripheral wall, and the leg portions of the first and second yokes are individually accommodated in the space, The leg is in sliding contact with the peripheral walls of the first and second lens supports.

  The invention according to claim 5 is the invention according to any one of claims 1 to 4, wherein the first lens support and the second lens support are separated from each other along the optical axis direction. It is located.

  According to a sixth aspect of the present invention, in the first or fifth aspect of the present invention, the first and second lens supports are held by a spring, and the spring is not energized in the coil. The support is biased toward the base.

  According to the first aspect of the present invention, the first and second lens supports move linearly in the optical axis direction of the lens by electromagnetic force generated by energizing the coil. The direction of movement of the lens) coincides, and therefore the drive loss is extremely small. As a result, the moving speed of the lens can be increased and the responsiveness can be improved. In other words, since the drive loss is small and the response and mobility are excellent, the lens can be efficiently moved by a desired amount in the optical axis direction in a narrow space, which is suitable for mounting on a small camera.

  In addition, since the first yoke and the second yoke (and thus the magnets and coils housed in the yoke) are arranged concentrically with each other, the entire lens driving device can be reduced in size.

  In addition, the lens support is moved by electromagnetic force, and since there is no engagement with a gear or cam groove as in the conventional case, it is possible to prevent rattling due to these precision errors, and there is no gear or cam, so the size can be reduced. Can be planned.

  According to the second aspect of the invention, the same effect as that of the first aspect of the invention can be obtained, and the first and second lens supports are frictionally engaged with the first and second yokes. Because it is designed to slide in the direction of the optical axis, the lens support is highly retainable and maneuverable, and sufficiently satisfies the subtle movements of the focus lens, etc., and the fixed magnification of the zoom lens, etc. be able to.

  According to the invention described in claim 3, the same effect as that of the invention described in claim 2 can be obtained, and the plurality of leg portions of the yoke disposed in the circumferential direction are slid on the inner surface of the lens support. Since they are in contact with each other, smooth sliding can be obtained with a sufficient holding force of the lens support against the yoke.

  According to the fourth aspect of the invention, the same effect as that of the third aspect of the invention can be obtained, and the leg portions of the yoke are individually accommodated in the space defined by the lens support. As a result, since the leg portion is in sliding contact with the peripheral wall of the lens support, it is possible to reliably prevent rattling of the yoke and the lens support in the circumferential direction, and the linear movement of the lens support is ensured and good. Can be realized.

  According to the fifth aspect of the present invention, the same effect as the first aspect of the present invention can be obtained, and the first lens support and the second lens support. Are spaced apart from each other along the optical axis direction. For example, if the zoom lens and the focus lens are respectively supported by the first lens support and the second lens support, the autofocus mechanism and A compact device having a magnification changing function can be realized efficiently.

  According to the sixth aspect of the invention, the same effect as that of the first or fifth aspect of the invention can be obtained, and the first and second lens supports are held by the spring, and the spring is Since the lens support is biased toward the base when the coil is not energized, it is possible to secure a sufficient holding force of the lens support against the yoke, Even when an impact occurs, the lens support is hardly shaken or rattled and has excellent impact resistance.

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

  1 to 3 show a first embodiment of the present invention. 1 is a cross-sectional view of the lens driving device of the present embodiment, FIG. 2A is a perspective view of the lens driving device of FIG. 1 viewed from above, and FIG. 2B is a lower side of the lens driving device. FIG. 3 is an exploded perspective view of the lens driving device of FIG.

  The lens driving device 1 according to the present embodiment is a lens driving device for an autofocus camera incorporated in a mobile phone, and as clearly shown in FIGS. 1 and 3, the first lens driving unit A and the second lens driving device. Part B. The first lens driving unit A has a first yoke 7 having a U-shaped cross section and a cylindrical shape. The first yoke 7 is attached to the base 2.

  The first yoke 7 has an inner peripheral wall 7b and an outer peripheral wall 7a arranged substantially concentrically, and a plurality of leg portions 25 are formed on the inner peripheral wall 7b at predetermined intervals along the circumferential direction. Has been. The magnet 6 is disposed inside the U-shape of the first yoke 7, and the coil 4 is disposed on the inner peripheral side of the magnet 6 inside the U-shape. In this case, the magnet 6 is fixed to the base 2 while being accommodated in a gap between the inner peripheral wall 7 b and the outer peripheral wall 7 a of the first yoke 7.

  A first lens support 5 is disposed on the inner peripheral side of the first yoke 7. A coil 4 is fixed to the outer periphery of the first lens support 5. The lens support 5 has a substantially cylindrical shape, and the lens 3 is housed therein, and is attached to the inner peripheral side of the first yoke 7 so as to be movable along the optical axis.

  In particular, in the present embodiment, the first lens support 5 slides in the optical axis direction by frictional engagement with the first yoke 7. Specifically, the first lens support 5 connects the inner peripheral wall 5b and the outer peripheral wall 5a, the inner peripheral wall 5b and the outer peripheral wall 5a, and the inner peripheral wall 5b and the outer peripheral wall 5a. And a partition wall 27 that forms a plurality of partitioned spaces 29. The leg portions 25 of the first yoke 7 are individually accommodated in the spaces 29, so that the leg portions 25 are the first ones. The lens support 5 is in sliding contact with the inner surface of the outer peripheral wall 5a (the leg portion 25 may be in sliding contact with the outer surface of the inner peripheral wall 5b).

  On the other hand, the second lens driving section B has a second yoke 12 having a U-shaped cross section and a cylindrical shape. The second yoke 12 is disposed on the outside of the first yoke 7 so as to be substantially concentric with the first yoke 7 and is mounted on the base 2 in a state where the U-shape is reversed with respect to the first yoke 7. The second yoke 12 has an inner peripheral wall 12b and an outer peripheral wall 12a arranged substantially concentrically, and a plurality of leg portions 30 are formed on the inner peripheral wall 12b at predetermined intervals along the circumferential direction. Has been. A magnet 11 is arranged inside the U-shape of the second yoke 12, and a coil 9 is arranged on the inner peripheral side of the magnet 11 inside the U-shape. In this case, the magnet 11 is fixed to the base 2 while being accommodated in a gap between the inner peripheral wall 12b and the outer peripheral wall 12a of the second yoke 12.

  A second lens support 10 is disposed on the inner peripheral side of the second yoke 12. A coil 9 is fixed to the outer periphery of the second lens support 10. The lens support 10 has a substantially cylindrical shape. The lens 8 is housed therein, and is attached to the inner peripheral side of the second yoke 12 so as to be movable along the optical axis.

  In particular, in the present embodiment, the second lens support 10 slides in the optical axis direction by frictional engagement with the second yoke 12. Specifically, the second lens support 10 connects the inner peripheral wall 10b and the outer peripheral wall 10a, and the inner peripheral wall 10b and the outer peripheral wall 10a by connecting the inner peripheral wall 10b and the outer peripheral wall 10a substantially concentrically with each other. And a partition wall 40 that forms a plurality of partitioned spaces 42. The leg portions 30 of the second yoke 12 are individually accommodated in the spaces 42, so that the leg portions 30 are second. The lens support 10 is in sliding contact with the inner surface of the outer peripheral wall 10a (the leg portion 30 may be in sliding contact with the outer surface of the inner peripheral wall 10b).

  In the above configuration, as can be seen from the drawing, the first lens support 5 and the second lens support 10 are positioned apart from each other along the optical axis direction. In such a lens driving device 1, the first and second lens supports 5 and 10 are linear in the optical axis direction of the lens by electromagnetic force (Fleming's left-hand rule) generated by energizing the coils 4 and 9. Move to.

  As described above, in the present embodiment, the first and second lens supports 5 and 10 move linearly in the direction of the optical axis of the lens by the electromagnetic force generated by energizing the coils 4 and 9, and therefore the direction of thrust And the moving direction of the lens support (lens) coincide with each other, and therefore the driving loss is extremely small. As a result, the moving speed of the lens can be increased and the responsiveness can be improved. That is, since the lens driving device 1 of the present embodiment has low driving loss and excellent response and mobility, the lens can be efficiently moved by a desired amount in the optical axis direction in a narrow space. Suitable for mounting on small cameras.

  In the present embodiment, the first yoke 7 and the second yoke 12 (and thus the magnets 4 and 9 and the coils 6 and 11 housed in the yokes 7 and 12) are arranged concentrically with each other. Therefore, it is possible to reduce the size of the entire lens driving device.

  Further, in this embodiment, the lens supports 5 and 10 are moved by electromagnetic force, and since there is no engagement with a conventional gear or cam groove, it is possible to prevent rattling due to these accuracy errors, and to prevent the gear from rotating. Since there is no cam or cam, miniaturization can be achieved.

  In the present embodiment, the first and second lens supports 5 and 10 slide in the optical axis direction by frictional engagement with the first and second yokes 7 and 12, The lens supports 5 and 10 are excellent in retainability and mobility, and can sufficiently satisfy the delicate movements of the focus lens and the like and the magnification fixing in the zoom lens and the like.

  Further, in the present embodiment, the plurality of leg portions 25 and 30 of the yokes 7 and 12 arranged in the circumferential direction are in sliding contact with the inner surfaces of the lens supports 5 and 10, so Smooth sliding can be obtained in a state in which the holding force of the lens supports 5 and 10 is sufficiently secured.

  Further, in the present embodiment, the leg portions 25 and 30 of the yokes 7 and 12 are individually accommodated in the partitioned spaces 29 and 42 of the lens supports 5 and 10, so that the leg portions 25 and 30 are the lens. Since it is in sliding contact with the peripheral walls of the supports 5 and 10, the rattling of the yokes 7 and 12 and the lens supports 5 and 10 in the circumferential direction is reliably prevented, and the linear support of the lens supports 5 and 10 is prevented. The movement can be realized surely and satisfactorily.

  In the present embodiment, since the first lens support 5 and the second lens support 10 are spaced apart from each other along the optical axis direction, for example, the first lens support 5 and the second lens If the zoom lens and the focus lens are supported on the support 10, respectively, a compact device having both an autofocus mechanism and a magnification changing function can be efficiently realized.

  FIG. 4 shows a second embodiment of the present invention. In the present embodiment, the first and second lens supports 5 and 10 are held by springs 60 and 62, and the springs 60 and 62 are based on the lens supports 5 and 10 in a state where no current is supplied to the coils. Energizing towards 2. Other configurations are the same as those in the first embodiment.

  According to such a configuration, since the first and second lens supports 5 and 10 are held by the springs 60 and 62, there is no need to slidably hold the lens supports 5 and 10 on the yokes 7 and 12. . However, it may be combined with the sliding contact holding configuration as in this embodiment.

  According to the present embodiment, the holding force of the lens supports 5 and 10 with respect to the yokes 7 and 12 can be sufficiently ensured, and the lens support can be used even when, for example, shaking or impact occurs when the camera is carried. It does not easily shake or rattle and has excellent impact resistance.

It is sectional drawing of the lens drive device which concerns on 1st Embodiment of this invention. (A) is the perspective view which looked at the lens drive device of FIG. 1 from the upper side, (b) is the perspective view which looked at the lens drive device from the lower side. It is a disassembled perspective view of the lens drive device of FIG. It is sectional drawing of the lens drive device which concerns on 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Lens drive device 2 Base 4,9 Coil 5 1st lens support body 6,11 Magnet 7 1st yoke 10 2nd lens support body 12 2nd yoke

Claims (6)

A first yoke having a U-shaped cross section and a cylindrical shape;
A second yoke having a cylindrical shape with a U-shaped cross section disposed substantially concentrically with the first yoke on the outside of the first yoke;
A base on which the first and second yokes are mounted;
A magnet and a coil disposed inside each U-shape of the first and second yokes;
A first lens support disposed on the inner peripheral side of the first yoke and having a coil fixed to the outer periphery;
A second lens support disposed on the inner peripheral side of the second yoke and having a coil fixed to the outer periphery;
With
The lens driving device, wherein the first and second lens supports are linearly moved in the optical axis direction of the lens by electromagnetic force generated by energizing the coil.   The first lens support slides in the optical axis direction by frictional engagement with the first yoke, and the second lens support slides in the optical axis direction by frictional engagement with the second yoke. The lens driving device according to claim 1.   The first and second yokes have an inner peripheral wall and an outer peripheral wall disposed substantially concentrically with each other, and a plurality of legs are formed at predetermined intervals along the circumferential direction on the inner peripheral wall. 3. The lens driving device according to claim 2, wherein the leg portion is in sliding contact with the inner surfaces of the first and second lens supports.   The first and second lens supports have a plurality of partitioned spaces between the inner peripheral wall and the outer peripheral wall by connecting the inner peripheral wall and the outer peripheral wall disposed substantially concentrically with each other, and the inner peripheral wall and the outer peripheral wall. And the leg portions of the first and second yokes are individually accommodated in the space so that the leg portions are in sliding contact with the peripheral walls of the first and second lens supports. The lens driving device according to claim 3, wherein:   5. The lens driving device according to claim 1, wherein the first lens support body and the second lens support body are spaced apart from each other along the optical axis direction. . The first and second lens supports are held by a spring, and the spring biases the lens support toward the base in a state where the coil is not energized. Item 6. The lens driving device according to Item 5.

Images