JP4364006B2 - Lens drive device - Google Patents

Description

  The present invention relates to a lens driving device used for a camera or the like.

As a lens driving device mounted on a camera-equipped mobile phone or the like, a type that transmits the rotation of a motor to a moving lens body via a gear mechanism and a cam mechanism and drives the lens in the optical axis direction has been proposed ( For example, see Patent Document 1).
JP 2003-309756 A

  However, the lens driving device disclosed in Patent Document 1 has a complicated structure of movable parts such as a gear mechanism and a cam mechanism, so that it is difficult to reduce the size, the weight, and the cost. In addition, since mechanical parts are used, there is a problem that sound is generated at the gear meshing part and the sliding part between the mechanical parts, and the reliability is low.

  In view of the above problems, the object of the present invention is to reduce the size, weight, and cost by performing lens driving only by magnetic action without using any gear mechanism or cam mechanism for lens driving. An object of the present invention is to provide a lens driving device capable of improving reliability and suppressing generation of sound.

In order to solve the above-described problem, in the present invention, a moving lens body including a lens is provided between a first position and a second position that is separated from the first position in the optical axis direction of the lens . A lens driving device that moves along the optical axis between the first magnetic means formed on the moving lens body, and a lens barrel that is disposed so as to surround the moving lens body on the outer peripheral side; The lens barrel is arranged on the outer peripheral side of the lens barrel so as to be movable in the optical axis direction, and when moving in the optical axis direction, the moving lens body is moved to the optical axis by a magnetic action with the first magnetic means. A second magnetic means for following the direction; and a third magnetic means for moving the second magnetic means in the direction of the optical axis by a magnetic action of the second magnetic means. Characterized by

In the present invention, when the second magnetic means is moved in the optical axis direction outside the lens barrel by the magnetic action between the second magnetic means and the third magnetic means, Due to the magnetic action between the magnetic means and the second magnetic means, the moving lens body follows the movement of the second magnetic means. Therefore, the lens can be moved along the optical axis.

  In the present invention, the first magnetic means is composed of a magnet or a magnetic material, the second magnetic means is composed of one of a magnet and a coil, and the third magnetic means is It is comprised with the other of a magnet or a coil.

  In the present invention, the second magnetic means moves in the optical axis direction while sliding on the outer peripheral surface of the lens barrel.

  In the present invention, it is preferable that the first magnetic means move in the optical axis direction in a non-contact state with the inner peripheral surface of the lens barrel. With this configuration, since friction does not occur between the first magnetic means and the inner peripheral surface of the lens barrel, the load can be reduced, so that the size of each magnetic means can be reduced. Further, since the first magnetic means does not slide on the inner peripheral surface of the lens barrel, no foreign matter is generated due to wear. Therefore, the reliability can be improved and the reflection of foreign matters can be prevented.

In the present invention, at least one of the first position and the second position is provided with lens centering means for receiving the moving lens body so as to position the center of the lens on the optical axis. Preferably it is. With this configuration, even if a clearance is provided between the first magnetic means and the lens barrel so as to keep them in a non-contact state, the lens is stopped with the center of the lens positioned on the optical axis. be able to.

  In the present invention, it is preferable that at least one of the first position and the second position is configured with a stopper that abuts the moving lens body and defines a stop position of the moving lens body. . With this configuration, the lens can be accurately stopped at a predetermined position.

  In the present invention, it is preferable that a magnetic pressure generating means for applying a pressure in a direction in which the movable lens body whose position is defined by the stopper is further brought into contact with the stopper mechanism is provided. If comprised in this way, even if a vibration etc. are added from the outside, a lens can be stopped exactly in a predetermined position.

  In the present invention, it is preferable that the periphery of the movable lens body is sealed by the lens barrel. If comprised in this way, the penetration | invasion of foreign materials, such as dust and dust, can be prevented inside the lens barrel in which the moving lens body is arranged. Therefore, the reliability can be improved and the reflection of foreign matters can be prevented.

The lens driving device according to the present invention moves the second magnetic means in the optical axis direction outside the lens barrel by the magnetic action between the second magnetic means and the third magnetic means. The moving lens body follows the movement of the second magnetic means by the magnetic action between the first magnetic means and the second magnetic means, and the lens is moved along the optical axis. For this reason, since the lens can be driven only by a magnetic action, no gear mechanism or cam mechanism is required. Therefore, size reduction, weight reduction, cost reduction, and improvement in reliability can be achieved, and generation of sound due to sliding or the like can be suppressed.

  A lens driving device to which the present invention is applied will be described below with reference to the drawings.

[Embodiment 1]
(overall structure)
FIG. 1 is a cross-sectional view of a lens driving device to which the present invention is applied. In FIG. 1, the lens driving device 1 according to the present embodiment includes, as a lens system, a fixed lens 11, a moving lens 21, and a fixed lens 31 in order from the subject side in the optical axis direction (the direction along the optical axis L). A cylindrical lens barrel 4 is arranged so as to surround the lenses 11, 21, and 31. A diaphragm 23 is fixed to the rear side (back side in the optical axis direction) of the moving lens 21. Of the three lenses, the fixed lens 11 is fixed to the tip portion of the lens barrel 4 by a step and a ring-shaped lens retainer 2. The fixed lens 31 is fixed to the base end portion of the cylindrical lens barrel 4 using a step. The moving lens 21 is configured as a moving lens body 20 that is integral with a cylindrical lens holder portion 22 on the outer peripheral side. Here, the lower end part 221 of the lens holder part 22 is formed as a plurality of protrusions spaced in the circumferential direction, and the upper end part 222 of the lens holder part 22 is also formed as a plurality of protrusions spaced in the circumferential direction. The fixed lenses 21 and 31 and the moving lens body 20 are made of a resin such as PC, POM, PA, AS, ABS, and PE.

  A plurality of recesses 111 are formed on the rear end surface of the fixed lens 11 so as to be spaced apart from each other in the circumferential direction. These recesses 111 cooperate with an upper end portion 222 of the lens holder portion 22 of the moving lens 21 and will be described later. It functions as a stopper and lens centering means. In addition, a plurality of concave portions 311 are formed on the subject-side end surface of the fixed lens 31 so as to be separated from each other in the circumferential direction. These concave portions 311 cooperate with the lower end portion 221 of the lens holder portion 22 of the moving lens 21, It functions as a stopper and lens centering means described later.

  In the lens driving device 1 of this embodiment, the optical system, the lens barrel 4 and the like are housed in a case 9. The case 9 includes a case main body 91 and a case lid 92 that fits into the case main body 91 from the optical axis direction. The case lid 92 and the case main body 91 are formed with openings for securing an optical path. The lens barrel 4 has a lower end held by the case body 91 and an upper end held by the case lid 92.

(Drive mechanism)
In this embodiment, the optical axis between the first position on the far side separating the moving lens 21 in the optical axis direction and the second position on the subject side (the position where the moving lens 21 is stopped in FIG. 1). For the purpose of driving in the direction, first, a ring-shaped magnet 5 (first magnetic means) is fixed to the outer peripheral side of the moving lens body 20, and this magnet 5 is fixed in the circumferential direction. Radially magnetized to have the number of poles. Here, a predetermined clearance is provided between the outer peripheral surface of the magnet 5 and the inner peripheral surface of the lens barrel 4, and the outer peripheral surface of the magnet 5 and the inner peripheral surface of the lens barrel 4 are in a non-contact state. .

  Further, a ring-shaped magnet 6 (second magnetic means) is disposed on the outer peripheral side of the lens barrel 4, and this magnet 6 has the same number of poles as the magnet 5 in the circumferential direction. Radial magnetized. Here, the inner peripheral surface of the magnet 6 is loosely in contact with the outer peripheral surface of the lens barrel 4 and can move in the optical axis direction. Further, when the magnet 6 moves in the optical axis direction, the inner peripheral surface slides on the outer peripheral surface of the lens barrel 4.

  Furthermore, in this embodiment, a ring-shaped first stator 71 and a ring-shaped second stator 72 are arranged as third magnetic means on both sides of the magnet 6 in the optical axis direction. The first stator 71 includes an annular yoke 711 and an annular coil 712 in an annular recess 912 formed by an annular protrusion 911 protruding in the optical axis direction inside the case main body 91. The second stator 72 includes an annular yoke 721 and an annular coil 722 in an annular recess 922 formed by an annular protrusion 921 protruding in the optical axis direction inside the case lid 92.

(Operation and main effect of this form)
In the lens driving device 1 configured as described above, when power is supplied to both or one of the coils 712 and 722, a magnetic attractive force or repulsive force (magnetic action) is generated between the coils 712 and 722 and the magnet 6. The magnet 6 moves in the optical axis direction until it hits the annular protrusion 921 or the annular protrusion 911. For this reason, the moving lens body 20 moves in the optical axis direction and the moving lens 21 moves in the optical axis direction due to the magnetic attractive force (magnetic action) generated between the magnet 6 and the magnet 5.

At this time, when the movable lens body 20 moves to the subject side, the upper end 222 of the lens holder portion 22 enters the recess 111 formed on the fixed lens 11 side, and the upper end portion 222 of the lens holder portion 22. Comes into contact with the bottom (stopper) of the concave portion 111 of the fixed lens 11. Therefore, the moving lens 21 stops at the second position. Further, the upper end portion 222 of the lens holder portion 22 is fitted into the concave portion 111 (lens centering means) of the fixed lens 11 so that the center position of the moving lens 21 is defined on the optical axis L at the second position. It becomes a state.

Conversely, when the movable lens body 20 moves to the back side, the lower end 221 of the lens holder portion 22 enters the recess 311 formed on the fixed lens 31 side, and the lower end portion 221 of the lens holder portion 22. Comes into contact with the bottom (stopper) of the recess 311 of the fixed lens 31. Accordingly, the moving lens 21 stops at the first position. Further, when the lower end portion 221 of the lens holder portion 22 is fitted into the concave portion 311 (lens centering means) of the fixed lens 31, the center position of the moving lens 21 is in a state defined on the optical axis L.

As described above, in the lens driving device 1 of the present embodiment, the magnet 6 is moved in the optical axis direction outside the lens barrel 4 by the magnetic action between the magnet 6 and the stators 71 and 72, and the magnet 5. And the magnet 6 cause the moving lens body 20 to follow the movement of the magnet 6 and move the moving lens 21 along the optical axis L. For this reason, since the lens can be driven only by a magnetic action, no gear mechanism or cam mechanism is required. Therefore, size reduction, weight reduction, cost reduction, and improvement in reliability can be achieved, and generation of sound due to sliding or the like can be suppressed.

  Further, in this embodiment, since a clearance is secured between the outer peripheral surface of the magnet 5 and the inner peripheral surface of the lens barrel 4, the magnet 5 is not in contact with the inner peripheral surface of the lens barrel 4. Move in the direction of the optical axis. Therefore, since no friction occurs between the magnet 5 and the inner peripheral surface of the lens barrel 4, the load can be reduced. Therefore, downsizing of members such as the magnets 5 and 6 can be achieved. Further, since the magnet 5 does not slide on the inner peripheral surface of the lens barrel 4, no foreign matter is generated due to wear. Therefore, the reliability can be improved and the reflection of foreign matters can be prevented.

  Moreover, stoppers (concave portions 111 and 311) that cooperate with the lens holder portion 22 of the moving lens 21 are formed at both the first position and the second position. For this reason, the movable lens 21 can be accurately stopped at a predetermined position in both the first position and the second position. In both the first position and the second position, lens centering means (concave portions 111 and 311) that cooperate with the lens holder portion 22 of the moving lens 21 are formed. For this reason, the center of the moving lens 21 is set to the optical axis even if a clearance is provided between the outer peripheral surface of the magnet 5 and the inner peripheral surface of the lens barrel 4 in both the first position and the second position. It can be stopped in a state of being positioned on L.

  Furthermore, in this embodiment, the moving lens body 20 is completely sealed around the lens barrel 14. Therefore, it is possible to prevent foreign matters such as dust and dust from entering the lens barrel 4 in which the movable lens body 20 is disposed. Therefore, the reliability can be improved and the reflection of foreign matters can be prevented.

[Embodiment 2]
2A and 2B are a cross-sectional view of a lens driving device according to Embodiment 2 of the present invention and an explanatory view showing the stopper mechanism in an enlarged manner. The basic configuration of the lens driving device according to the present embodiment and later-described third embodiment is the same as that of the first embodiment. Therefore, common portions are denoted by the same reference numerals and description thereof is omitted. To do.

  As shown in FIG. 2A, the lens driving device 1 of the present embodiment is also a fixed lens in order from the subject side in the optical axis direction (direction along the optical axis L) as a lens system, as in the first embodiment. 11, a moving lens 21 and a fixed lens 31, and the moving lens 21 is configured as a moving lens body 20 that is integral with a cylindrical lens holder portion 22 on the outer peripheral side. In this embodiment, the fixed lens 11 is fixed to a ring-shaped lens holder 2, and the lens holder 2 is fixed to the lens barrel 4.

  In this embodiment as well, as in Embodiment 1, the stopper 111 and the recess 111 that functions as lens centering means are formed in cooperation with the upper end portion 222 of the lens holder portion 22 of the moving lens 21. Then, the recessed part 11 is formed in the lens holding | suppressing 2 side.

  In this embodiment, as shown in an enlarged view in FIG. 2B, the upper end portion 222 of the lens holder portion 22 has a taper 223 formed on the outer peripheral side. Further, the recess 111 has a structure in which a corner on the outer peripheral side is cut off to form a taper 112 and an inner peripheral side surface parallel to the optical axis L extends from the end of the taper 112 to the back.

  For this reason, when the upper end 222 of the lens holder part 22 enters the recess 111, the tapers 112 and 223 function as a guide, so that the upper end 222 of the lens holder part 22 smoothly enters the recess 111, and the taper 112, Since the two contacts 223 contact each other, the center position of the moving lens 21 is reliably defined on the optical axis L at the second position.

  In this embodiment, the concave portion 311 that functions as a stopper and lens centering means in cooperation with the lower end portion 221 of the lens holder portion 22 of the moving lens 21 is formed in the lens barrel 4. Here, the lower end portion 221 and the concave portion 311 of the lens holder portion 22 have a taper similar to the taper as shown in FIG. Therefore, the center position of the moving lens 21 is reliably defined on the optical axis L even at the first position.

[Embodiment 3]
FIG. 3 is a cross-sectional view of a lens driving device according to Embodiment 3 of the present invention. Since the basic configuration of the lens driving device of the present embodiment is the same as that of the first and second embodiments, common portions are denoted by the same reference numerals and description thereof is omitted.

  As shown in FIG. 3, the lens driving device 1 of the present embodiment also moves the fixed lens 11 in order from the subject side in the optical axis direction (direction along the optical axis L) as a lens system, as in the first embodiment. The movable lens 21 includes a lens 21 and a fixed lens 31. The movable lens 21 is configured as a movable lens body 20 integrated with a cylindrical lens holder portion 22 on the outer peripheral side.

When power is supplied to both or one of the coils 712 and 722, a magnetic attractive force or repulsive force (magnetic action) is generated between the coils 712 and 722 and the magnet 6, and the magnet 6 has an annular protrusion 921. Alternatively, it moves in the optical axis direction until it hits the annular protrusion 911. Further, the moving lens body 20 moves in the optical axis direction and the moving lens 21 moves in the optical axis direction by a magnetic attractive force (magnetic action) generated between the magnet 6 and the magnet 5.

At this time, when the movable lens body 20 moves to the subject side, the upper end 222 of the lens holder portion 22 enters the recess 111 formed on the fixed lens 11 side, and the upper end portion 222 of the lens holder portion 22. Comes into contact with the bottom (stopper) of the concave portion 111 of the fixed lens 11. Therefore, the moving lens 21 stops at the second position. Conversely, when the movable lens body 20 moves to the back side, the lower end 221 of the lens holder portion 22 enters the recess 311 formed on the fixed lens 31 side, and the lower end portion 221 of the lens holder portion 22. Comes into contact with the bottom (stopper) of the recess 311 of the fixed lens 31. Accordingly, the moving lens 21 stops at the first position.

  In the lens driving device 1 configured as described above, in the present embodiment, a pressure generating means is configured. That is, when performing the lens driving described above, the magnetic center of the magnet 5 in the optical axis direction moves within the range indicated by the arrow L5. On the other hand, the magnetic center of the magnet 6 in the optical axis direction moves in the range indicated by the arrow L6 and is slightly wider than the moving range of the magnet 5.

  Therefore, in the present embodiment, the magnetic center in the optical axis direction of the magnet 6 is more than the magnetic center in the optical axis direction of the magnet 5 with the moving lens 21 stopped at the second position as shown by the solid line. Located on the subject side. Therefore, a magnetic pressure is applied to the moving lens body 20 to urge the moving lens body 20 whose position is regulated by the stopper toward the subject side. 21 can be accurately stopped at the second position.

  Further, with the moving lens 21 stopped at the first position as indicated by the dotted line, the magnetic center of the magnet 6 in the optical axis direction is further back than the magnetic center of the magnet 5 in the optical axis direction. . Therefore, a magnetic pressure is applied to the moving lens body 20 to urge the moving lens body 20 whose position is defined by the stopper toward the back side. 21 can be accurately stopped at the first position.

[Other embodiments]
In the above embodiment, the example in which the moving lens 21 is stopped at the first position on the far side and the second position on the subject side that are separated in the optical axis direction has been described. However, the magnet 6 is magnetized. In addition, the feeding of the coils 712 and 722 may be controlled to stop the moving lens 21 at the center in the optical axis direction as shown in FIG.

  In the above embodiment, a magnet is used as the first magnetic means and the second magnetic means, and a coil is used as the third magnetic means. However, a magnetic material is used as the first magnetic means, and the second magnetic means is the second magnetic means. One of the magnet and the coil may be used as the magnetic means, and the other of the magnet and the coil may be used as the third magnetic means.

The lens driving device according to the present invention moves the second magnetic means in the optical axis direction outside the lens barrel by the magnetic action between the second magnetic means and the third magnetic means. The moving lens body follows the movement of the second magnetic means by the magnetic action between the first magnetic means and the second magnetic means, and the lens is moved along the optical axis. For this reason, since the lens can be driven only by a magnetic action, no gear mechanism or cam mechanism is required. Therefore, size reduction, weight reduction, cost reduction, and improvement in reliability can be achieved, and generation of sound due to sliding or the like can be suppressed.

It is sectional drawing of the lens drive device which concerns on Embodiment 1 of this invention. (A), (B) is sectional drawing of the lens drive device which concerns on Embodiment 2 of this invention, and explanatory drawing which expands and shows the stopper mechanism. It is sectional drawing of the lens drive device which concerns on Embodiment 3 of this invention. It is sectional drawing of the lens drive device which concerns on other embodiment of this invention.

DESCRIPTION OF SYMBOLS 1 Lens drive device 2 Lens holding | maintenance 4 Lens barrel 5 Magnet (1st magnetic means)
6 Magnet (second magnetic means)
11, 31 Fixed lens 20 Moving lens body 21 Moving lenses 71, 72 Stator (third magnetic means)
111, 311 recess (stopper, lens centering means)
112, 223 taper

Claims (8)

A lens driving device that moves a moving lens body provided with a lens along the optical axis between a first position and a second position that is separated from the first position in the optical axis direction of the lens. Because
First magnetic means formed on the moving lens body;
A lens barrel arranged to surround the moving lens body on the outer peripheral side;
The lens barrel is arranged on the outer peripheral side of the lens barrel so as to be movable in the optical axis direction. When the lens barrel moves in the optical axis direction, the moving lens body is moved in the optical axis direction by a magnetic action with the first magnetic means. A second magnetic means to follow,
A lens driving device comprising: third magnetic means for moving the second magnetic means in the optical axis direction by a magnetic action with the second magnetic means. In Claim 1, said 1st magnetic means comprises a magnet or a magnetic body,
The second magnetic means comprises one of a magnet and a coil;
3. The lens driving device according to claim 3, wherein the third magnetic means is constituted by the other of a magnet and a coil.   3. The lens driving device according to claim 1, wherein the second magnetic means moves in the optical axis direction while sliding on an outer peripheral surface of the lens barrel.   4. The lens driving device according to claim 1, wherein the first magnetic means moves in the optical axis direction in a non-contact state with an inner peripheral surface of the lens barrel. 5. The lens centering means according to claim 4, wherein at least one of the first position and the second position includes a lens centering unit that receives the moving lens body so as to position the center of the lens on the optical axis. A lens driving device.   6. The stopper according to claim 1, wherein at least one of the first position and the second position is a stopper that abuts the moving lens body and defines a stop position of the moving lens body. A lens driving device.   The magnetic pressure generating means according to claim 6, further comprising a magnetic pressure generating means for applying a pressure in a direction in which the movable lens body whose position is defined by the stopper is further brought into contact with the stopper. Lens drive device.   8. The lens driving device according to claim 1, wherein the moving lens body is hermetically sealed by the lens barrel.

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