JP2007248684A - Camera module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a step motor for forward and backward rotation by which downsizing and thinning of a camera module are attained and large drive torque is obtained with low power consumption. <P>SOLUTION: The camera module is provided with a columnar lens barrel which stores a lens and the step motor which moves the lens barrel in the optical axis direction of the lens. The step motor has a rotary body magnetized to two poles in a direction perpendicular to the axis of rotary body, and a first excitation means and a second excitation means for freely rotatably driving the rotary body. The rotary body and the first and second excitation means arranged so that the longitudinal direction becomes the optical axis direction of the lens are arranged, respectively along the outer periphery of the cylindrical lens barrel. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a camera module provided with a forward / reverse rotating step motor for driving a lens unit for performing an autofocus function (autofocus) used in a digital camera or a mobile phone.

  In the technical field, there is an increasing demand for downsizing of a camera module including a forward / reverse rotating step motor for driving a lens unit, such as a reduction in plane area and a reduction in thickness in the optical axis direction. Under such circumstances, a camera module is disclosed in which the axial direction of the coil body of the step motor is orthogonal to the optical axis direction of the camera module in order to reduce the thickness in the optical axis direction (for example, Patent Documents). 1, see Patent Document 2).

  The camera module described in Patent Document 1 includes at least one movable lens holder that holds a movable lens and is provided with a cam drive shaft, a one-phase step motor having a coil body that is long in one direction, and a movable A lens barrel that supports the lens holder so as to be movable in the optical axis direction. Then, the cam drive shaft of the movable lens holder is arranged so that the axial direction thereof is a first direction orthogonal to the optical axis direction, and the coil body of the one-phase step motor is arranged, and the axial direction thereof is the optical axis. The configuration is such that the second direction is perpendicular to the direction and perpendicular to the first direction.

  However, since the step motor described in Patent Document 1 is composed of a single-phase step motor, it is excellent in small size and low power consumption. However, the high speed of the step motor necessary for performing the autofocus function (autofocus) Forward / reverse rotation and high-precision positioning characteristics cannot be obtained. In addition, it is difficult to apply this step motor to a camera module that is small and requires high torque.

Next, a step motor that is small in size and excellent in high-speed forward / reverse rotation and high-accuracy positioning characteristics and capable of obtaining high torque will be described. FIG. 11 is a plan view for explaining the step motor for forward / reverse rotation described in Patent Document 2. FIG.
The step motor described in Patent Document 2 is provided with a rotor 101 having a permanent magnet and a stator 111 that is rotatably attached and has three magnetic pole faces around the rotor 101. The stator 111 includes a first arm 107, a second arm 109, and a third arm 108. A first electric coil 103 is attached to the first arm 107, and a second electric coil 105 is attached to the second arm 109.

  A control circuit (which is electrically connected to the first and second electric coils 103, 105, applies an electric pulse independently to the first and second electric coils 103, 105 and controls the polarity thereof) (Not shown), and by this control circuit, the rotor 101 can rotate 360 degrees per rotation in two steps in response to the magnetic field.

Next, a configuration of a camera module in which a conventional bi-directional step motor is placed flat and combined with a lens unit will be described. FIG. 12 is a plan view showing the configuration of a camera module in which a bidirectional step motor 115 is placed flat on a base (not shown) on which the lens unit 113 is placed.
As shown in the drawing, in the camera module in which the step motor 115 is placed flat, the optical axis 43 direction (Z-axis direction) of the lens unit 113 and the rotation axis direction of the rotor 101 of the bi-directional step motor 115 are Arranged to be parallel. In this way, the camera module in which the step motor 115 is laid flat is only the height of the lens unit in the Z-axis direction, so that the camera module can be reduced in height, but the area of the XY plane is a dotted line. Because it is an enclosed area, it becomes larger. For this reason, it is difficult to reduce the size of the camera module in which the step motor 115 and the lens unit 113 are arranged.

Next, a camera module in which a conventional bi-directional step motor is placed vertically and combined with a lens unit will be described. FIG. 13A shows a perspective view of the camera module showing the positional relationship between the bidirectional step motor 115 and the lens unit 113, and FIG. 13B shows a plan view of FIG. ing.
As shown in the drawing, the camera module in which the step motor 115 is installed vertically has an arrangement in which the optical axis 43 direction (Z-axis direction) of the lens unit 113 and the coil body axis direction of the step motor 115 are parallel. The flat area of the module is a range surrounded by a dotted line shown in FIG. Therefore, the area of the XY plane can be reduced as compared with the camera module shown in FIG.

  Further, as shown in FIG. 13B, the step motor 115 in the camera module is disposed at a position close to the lens unit 113, so that the plate cam 35 incorporated in the output shaft 33 and the lens unit 113. Due to the contact with a part, the driving force of the step motor 115 can be efficiently transmitted to the lens unit 113.

Japanese Unexamined Patent Publication No. 2004-191657 (page 2-4, FIG. 1) US Pat. No. 6,731,093 (FIG. 1)

  However, the camera module using the step motor described in Patent Document 2 has the following problems.

  The small camera module incorporated in the cellular phone has a lower height in the direction of the optical axis 43 and a smaller plane area perpendicular to the direction of the optical axis 43 as shown in FIGS. Therefore, there is a demand for downsizing the module. The longitudinal direction of the first and second electric coils 103 and 105 of the step motor 115 is arranged so that the axial direction of the first and second electric coils 103 and 105 is parallel to the direction of the optical axis 43 of the lens unit 113. In this case, the plane area of the XY plane can be reduced as described above, but it has been difficult to reduce the height in the direction of the optical axis 43.

  In order to reduce the height in the direction of the optical axis 43, the coil length L of the first and second electric coils 103 and 105 must be shortened. However, if the coil length L in the first and second electric coils 103 and 105 is shortened, the resistance value decreases when a coil having the same wire diameter as that of the conventional coil is wound. Power consumption will be increased if installed in the system. Further, when a thin wire diameter coil is wound around the first and second electric coils 103 and 105, the driving torque of the rotor 101 is insufficient, so that low power consumption becomes difficult.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above-described problems and to provide a camera module that uses a forward and reverse rotating step motor and achieves a small size and a small thickness.

In order to achieve the above object, the present invention basically employs a technical configuration as described below.

  The camera module of the present invention includes a cylindrical lens barrel that accommodates a lens, and a step motor that moves the lens barrel in the optical axis direction of the lens, and the step motor is in a direction orthogonal to the rotating body axis. The rotating body magnetized in two poles, the first exciting means for driving the rotating body, the second exciting means, the rotating body and the first and second exciting means are magnetized. A rotating body, and first and second excitation means arranged so that the longitudinal direction is the optical axis direction of the lens, along the outer periphery of the cylindrical lens barrel Each of them is arranged.

  Further, the camera module of the present invention has a magnetic circuit in which the yoke described above returns the magnetic flux generated by the first excitation means to the first excitation means via the first magnetic pole, the rotating body, and the central magnetic pole. And forming a magnetic circuit for returning the magnetic flux generated by the second excitation means to the second excitation means via the second magnetic pole, the rotating body, and the central magnetic pole. It is a feature.

  The camera module of the present invention using the forward / reverse rotating step motor has the effect that the camera module can be reduced in size and thickness, and a large driving torque can be obtained with low power consumption.

  The camera module of the present invention includes a cylindrical lens barrel that houses a lens, and a step motor that moves the lens barrel in the optical axis direction of the lens. The step motor includes a rotating body magnetized in two poles in a direction perpendicular to the rotating body axis, two first excitation means and a second excitation for driving the rotating body rotatably. Means. Furthermore, this camera module has a configuration including a yoke that magnetically connects the rotating body and the first and second excitation means. The most characteristic feature of the camera module of the present invention is that the rotating body and the first and second exciting means arranged so that the longitudinal direction is the optical axis direction of the lens are formed by a cylindrical lens mirror. It exists in having arrange | positioned along the outer periphery of a pipe | tube with each predetermined gap. Hereinafter, the configuration of the camera module of the present invention and the arrangement of the first and second excitation means, which are the above-described feature points, will be mainly described.

Hereinafter, the configuration of the camera module of the present invention will be described. FIG. 1 is a diagram showing a configuration of a camera module of the present invention using a step motor. FIG. 1 (a) is a perspective view of the camera module of the present invention, and FIG. 1 (b) is a plan view. Is shown.
As shown in FIGS. 1A and 1B, the camera module of the present invention includes a lens barrel 25 that holds a plurality of lenses. The lens barrel 25 has an axis passing through the center of the lens in the direction of the optical axis 43. It is held on a base (not shown) so as to be movable. Also, on the lower surface side of the lens barrel 25, there is a substrate (not shown) on which components such as an infrared filter (not shown), an image sensor, (not shown), and IC components and capacitors are mounted. Has been placed. Further, the step motor 1 provided so as to enclose the lens barrel 25 is rotatably held inside the yoke 7 and the rotating body accommodation hole 15 and is polarized in a direction perpendicular to the rotating body axis 3. A rotating body 5 made of a permanent magnet is provided, and a first exciting means 17 and a second exciting means 19 that perform excitation through a yoke 7 in order to rotate the rotating body 5 in the forward and reverse directions.

The magnetic flux generated by the first excitation means 17 configured as described above is transmitted to the first excitation means 17 via the first magnetic pole 9, the rotating body 5, and the central magnetic pole 11. Form. The magnetic path between the first excitation means 17 and the first magnetic pole 9 is provided with a substantially right-angled bent portion 42a, and the magnetic field between the first excitation means 17 and the central magnetic pole 11 is provided. The road is also provided with a substantially right-angled bent portion 42b.

  The magnetic flux generated by the second excitation means 19 forms a magnetic circuit that returns to the second excitation means 19 via the second magnetic pole 13, the rotating body 5, and the central magnetic pole 11. Similarly, a substantially right-angled bent portion 42 c is provided in the magnetic path between the second excitation means 19 and the second magnetic pole 13, and between the second excitation means 19 and the central magnetic pole 11. The magnetic path is also provided with a substantially right-angled bent portion 42d.

  In this way, the rotating body 5, the first excitation means 17, and the second excitation means 19 are arranged at predetermined intervals along the outer periphery of the cylindrical lens barrel 25, respectively. The flat area of the camera module shown in (1) can be kept within the range surrounded by the dotted line. That is, the longitudinal directions of the first and second exciting means 17 and 19 are aligned with the direction of the optical axis 43, and the first and second exciting means 17 and 19 together with the rotating body 5 are arranged on the outer periphery of the lens barrel 25. By arranging along the part, the plane area size of the camera module can be remarkably reduced as compared with the conventional configuration.

  The first exciting means 17 and the second exciting means 19 are configured by winding the same wire diameter with the same winding number N. Both ends of the windings of the first excitation means 17 and the second excitation means 19 are connected to an electrical connection portion 51, and the electrical connection portion 51 is connected to a drive circuit (not shown). A voltage pulse can be applied.

Next, the connection form between the yoke 7 constituting the step motor 1, the first excitation means 17, and the second excitation means 19 will be described in more detail. FIG. 2 is an exploded perspective view of the yoke 7, the first excitation means 17, and the second excitation means 19.
As shown in FIG. 2, the yoke 7 is provided with screw holes 61a and 61b. Similarly, the first and second exciting means 17 and 19 are also provided with screw holes 61a and 61b. The yoke 7 and the first excitation means 17 are aligned by a screw hole 61a and are closely fixed with screws to establish a magnetic connection. Similarly, the yoke 7 and the second exciting means 19 are aligned by the screw holes 61b and are closely fixed with screws to establish a magnetic connection.

  In this way, the electrical connection portion 51 can be provided in a plane parallel to the XY plane. Therefore, the length of the coils provided in the first and second excitation means 17 and 19 is determined by the optical axis of the camera module. 43 (refer to FIG. 1) can be ensured substantially corresponding to the thickness in the direction, and a coil having the same wire diameter as the conventional one can be sufficiently wound. Therefore, the camera module of the present invention can reduce the thickness in the direction of the optical axis 43, and can be a camera module with low power consumption and high torque.

Next, the operation of the forward / reverse rotation step motor used in the camera module of the present invention will be described with reference to FIGS. First, the first state will be described. FIG. 3 shows a drawing showing the first state.
As shown in FIG. 3, the N pole of the rotating body 5 faces the central magnetic pole 11 direction. At this time, the first excitation is performed so that the first magnetic pole 9 becomes the N pole and the second magnetic pole 13 becomes the S pole. A voltage pulse is applied to the means 17 and the second excitation means 19 to generate a magnetic flux. As a result, the magnetic fluxes of the first excitation means 17 and the second excitation means 19 are, as shown by arrows in the figure, the first magnetic pole 9, the rotating body 5, the second magnetic pole 13, and the second excitation. The magnetic circuit is configured to return to the means 19 and the first excitation means 17.

At this time, the N pole of the permanent magnet of the rotating body 5 and the N pole of the first magnetic pole 9 repel each other, and the S of the permanent magnet
Since the pole and the S pole of the second magnetic pole 13 repel each other, a rotating torque that rotates counterclockwise with respect to the drawing acts on the rotating body 5 so that the N pole faces the second magnetic pole 13. You can make it.

Next, the second state will be described. FIG. 4 shows a drawing showing the second state.
As shown in FIG. 4, the N pole of the rotating body 5 faces the second magnetic pole 13. At this time, the first magnetic pole 9 is the S pole, the second magnetic pole 13 is the S pole, and the central magnetic pole 11 is the N pole. A voltage is applied to the first exciting means 17 and the second exciting means 19 so as to be poles to generate magnetic flux. As a result, the magnetic flux of the first excitation means 17 forms a magnetic circuit that returns to the first excitation means 17 through the central magnetic pole 11, the rotating body 5, and the first magnetic pole 9, as shown by the arrows in the figure. To do. The magnetic flux of the second exciting means 19 constitutes a magnetic circuit that passes through the central magnetic pole 11, the rotating body 5, and the second magnetic pole 13 and returns to the second exciting means 19.

  At this time, the S pole of the rotating body 5 and the S pole of the first magnetic pole 9 repel each other, and the N pole of the rotating body 5 and the N pole of the center magnetic pole 11 repel each other. On the other hand, rotational torque in the counterclockwise direction acts, and the N pole can be directed 180 degrees opposite to the central magnetic pole 11 (the S pole is in the central magnetic pole 11 direction).

Next, the third state will be described. FIG. 5 shows a drawing showing the third state.
As shown in FIG. 5, when the S pole of the rotator 5 is oriented in the direction of the central magnetic pole 11, the first excitation means is set so that the first magnetic pole 9 becomes the S pole and the second magnetic pole 13 becomes the N pole. 17. A voltage is applied to the second excitation means 19 to generate a magnetic flux. As a result, the magnetic fluxes of the first excitation means 17 and the second excitation means 19 are, as shown by the arrows in the figure, the second excitation means 19, the second magnetic pole 13, the rotating body 5, the first excitation means 19. The magnetic circuit which flows like the magnetic pole 9 and the 1st excitation means 17 is comprised.

  At this time, the N pole of the rotating body 5 and the S pole of the first magnetic pole 9 are attracted, and the N pole of the rotating body 5 and the N pole of the second magnetic pole 13 are repelled. Rotational torque in the counterclockwise direction acts on this figure, and the N pole can be directed to the first magnetic pole 9 direction.

Next, the fourth state will be described. FIG. 6 shows a drawing showing the fourth state.
As shown in FIG. 6, when the N pole of the rotating body 5 faces the first magnetic pole 9, the first magnetic pole 9 is the N pole, the second magnetic pole 13 is the N pole, and the central magnetic pole 11 is the S pole. A voltage is applied to the first excitation means 17 and the second excitation means 19 so that a magnetic flux is generated. As a result, the magnetic flux of the first excitation means 17 passes through the first magnetic pole 9, the rotating body 5, and the central magnetic pole 11 and returns to the first excitation means 17 as indicated by the arrows in the figure. The magnetic flux of the 2nd excitation means 19 comprises, and the magnetic circuit which returns to the 2nd excitation means 19 through the 2nd magnetic pole 13, the rotary body 5, and the center magnetic pole 11 is comprised.

  At this time, the N pole of the rotator 5 and the N pole of the first magnetic pole 9 repel each other, the N pole of the rotator 5 and the S pole of the center magnetic pole 11 are attracted, and the S pole and the center pole of the rotator 5 are attracted. Since the S pole of 11 is repelled, the rotating body 5 is rotated by receiving a rotational torque in the counterclockwise direction with respect to this figure, and the N pole can face the direction of the central magnetic pole 11.

Next, a description will be given of a reduction mechanism that transmits the driving force of the step motor and a plate cam arrangement that converts the linear movement of the lens unit. FIG. 7 shows a cross-sectional view of the stepping motor and the lens barrel.
A rotor kana 39 having 10 teeth is assembled on the rotating body 5, and a first speed reducer gear 27 having 50 teeth is meshed with the gear of the rotor kana 39. There is a reducer pinion 29 with 10 teeth coaxially with the first reducer gear 27, and a second reducer gear 31 with 60 teeth is arranged at a position where the reducer pinion 29 meshes with the gear of the reducer pinion 29. Yes. An output shaft 33 is provided coaxially with the second reduction gear 31.

  As described above, the rotary motion of the rotating body 5 is transmitted by the rotor kana 39, the first and second speed reducer gears 27 and 31, and the gears and kana in the speed reducer kana 29, and rotates the output shaft 33. .

  Further, a plate cam 35 for converting a rotational motion into a linear motion in the direction of the optical axis 43 is fixed to the tip of the output shaft 33 by press-fitting or screwing. The plate cam 35 is in contact with the support portion 37 of the lens barrel 25 in a slidable state. Then, the driving force is transmitted by the reduction mechanism by the rotation of the rotating body 5, and the support portion 37 moves in the direction of the optical axis 43 as the plate cam 35 rotates, thereby moving the lens barrel 25 in the direction of the optical axis 43. be able to.

  The number of reduction gears, the number of teeth, the number of reduction gears, and the number of teeth of the first and second reduction gears 27 and 31 and reduction gear pinion 29 are not limited to the above. The lens barrel 25 is designed according to the moving distance, moving pitch, and moving speed.

Next, a mechanism in which the support portion 37 linearly moves up and down by the rotational movement of the plate cam 35 will be described. FIG. 8 shows the positional relationship between the plate cam 35 and the support portion 37. FIG. 8A shows the plate cam 35 and the support when the lens barrel connected to the support portion 37 is located at the lowest position. FIG. 4B shows the positional relationship between the plate cam 35 and the support portion 37 when the lens barrel is positioned at the uppermost position.
As shown in FIGS. 8A and 8B, the plate cam 35 has a substantially elliptical shape and is fixed to the output shaft 33 by press-fitting or screwing. Further, a support portion 37 provided so as to extend from the lens barrel (see FIG. 7) so as to come into contact with the outer periphery of the plate cam 35 is pressed against the plate cam 35 by an appropriate force by the coil spring 41, so that the plate cam 35. It is possible to slide on the outer periphery of.

  As shown in FIG. 8A, when the lens barrel 25 is located at the lowest position, the support portion 37 is in contact with the short diameter portion of the plate cam 35, and the output shaft 33 and the support portion 37 are the most. It will be in a state of approaching. The distance between the center of the output shaft 33 and the center of the support portion 37 at this time is assumed to be L1.

  As shown in FIG. 8B, when the lens barrel 25 is positioned at the uppermost position, the output shaft 33 rotates approximately 90 degrees with respect to the state of FIG. The cam 35 comes into contact with the long diameter portion. At this time, the output shaft 33 and the support portion 37 are farthest from each other, and the lens barrel 25 is positioned at the top with respect to the direction of the optical axis 43 (see FIG. 7). The distance between the center of the output shaft 33 and the center of the support portion 37 at this time is assumed to be L2.

  Accordingly, the movement amount of the support portion 37, that is, the lens barrel 25 (see FIG. 7) is L2-L1, and the position of the lens barrel 25 in the direction of the optical axis 43 is controlled by controlling the rotation angle of the output shaft 33. Can be arbitrarily moved or stopped between the distances L2-L1.

  Note that the shape of the plate cam 35 is not limited to the elliptical shape shown in FIGS. 8A and 8B, but is an optimum shape with design values determined by the moving amount, moving pitch, moving speed, etc. of the lens barrel 25. Should be selected.

Next, a second embodiment according to the present invention will be described. FIG. 9 is a plan view showing another configuration example of the camera module of the present invention, and FIG. 10 is a perspective view of a step motor in the camera module.
As shown in FIGS. 9 and 10, the configuration example shown in the second embodiment is the yoke 7 connected to the first and second exciting means 17 and 19 in the camera module shown in the first embodiment. The other configurations are the same except that the shape of each is different. Therefore, in the following description, this difference will be mainly described. Since the operation and action of this stepping motor are the same as those described in the first embodiment, the description here is omitted.

  As shown in FIG. 9, the camera module of the present invention includes a lens barrel 25 holding a plurality of lenses, as in the configuration example in the first embodiment, and the lens barrel 25 has an axis passing through the center of the lens. It is held so as to be movable in the direction of the optical axis 43. Further, the step motor 1 includes a yoke 7, a rotating body 5, first excitation means 17, and second excitation means 19. Further, as shown in FIG. 10, the rotating body 5 made of a permanent magnet is rotatably held inside the rotating body accommodation hole 15, and is two-pole magnetized in a direction perpendicular to the rotating body axis 3. .

  As shown in FIG. 10, the first magnetic pole 9 and the second magnetic pole 13 constituting the yoke 7 extend from the vicinity of the rotor housing hole 15 in the Z-axis direction, and then the lens barrel 25 (FIG. 9). First and second excitation means 17, which are bent at a position exceeding the upper surface of the lens barrel 25 and arranged on the back surface of the lens barrel 25 with respect to the rotating body 5 along the upper surface of the lens barrel 25. 19 is cross-linked and connected.

  The magnetic flux generated by the first exciting means 17 shown in FIG. 10 by the first and second magnetic poles 9 and 13 arranged in this way is the first magnetic pole 9, the rotating body 5, and the central magnetic pole 11. And a magnetic circuit returning to the first excitation means 17 is formed. The magnetic path between the first excitation means 17 and the first magnetic pole 9 is provided with a substantially right-angled bent portion 42a, and the magnetic field between the first excitation means 17 and the central magnetic pole 11 is provided. The road is also provided with a substantially right-angled bent portion 42b.

  The magnetic flux generated by the second excitation means 19 forms a magnetic circuit that returns to the second excitation means 19 via the second magnetic pole 13, the rotating body 5, and the central magnetic pole 11. Similarly, a substantially right-angled bent portion 42 c is provided in the magnetic path between the second excitation means 19 and the second magnetic pole 13, and between the second excitation means 19 and the central magnetic pole 11. The magnetic path is also provided with a substantially right-angled bent portion 42d.

  In this way, the rotating body 5, the first excitation means 17, and the second excitation means 19 are arranged along the outer periphery of the cylindrical lens barrel 25, respectively, and the first of the camera module shown in FIG. The planar shape in the XY plane connecting the first excitation means 17, the second excitation means 19, and the rotating body 5 is a substantially trapezoidal shape indicated by a dotted line in FIG. 9. That is, the longitudinal directions of the first and second exciting means 17 and 19 are aligned with the direction of the optical axis 43, and the first and second exciting means 17 and 19 together with the rotating body 5 are arranged on the outer periphery of the lens barrel 25. By arranging them at predetermined intervals along the part, the plane area size of the camera module can be remarkably reduced as compared with the conventional configuration.

  In the camera module of the present invention, the electrical connection portion 51 between the first and second magnetic poles 9 and 13 and the first and second exciting means 17 and 19 is provided on a plane parallel to the XY plane. Therefore, the lengths of the coils of the first and second exciting means 17 and 19 can be ensured substantially corresponding to the thickness 43 in the optical axis direction of the camera module. In the exciting means 17 and 19, a coil having the same wire length as in the prior art can be sufficiently wound, so that a camera module that can achieve a reduction in thickness and has high torque and low power consumption can be obtained.

It is a figure which shows the structural example of the camera module of this invention. It is a disassembled perspective view of the step motor in the camera module of this invention. It is a figure which shows the 1st state of the step motor in the camera module of this invention. It is a figure which shows the 2nd state of the step motor in the camera module of this invention. It is a figure which shows the 3rd state of the step motor in the camera module of this invention. It is a figure which shows the 4th state of the step motor in the camera module of this invention. It is sectional drawing explaining the driving force transmission mechanism in the camera module of this invention. It is a figure explaining the cam mechanism in the camera module of this invention. It is a top view which shows the other structural example of the camera module of this invention. It is a perspective view of the step motor in the camera module of the present invention. It is a top view which shows the structure of the step motor in the conventional camera module. It is a figure which shows schematic structure of the conventional camera module. It is a figure which shows schematic structure of the conventional camera module.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Step motor 3 Rotating body axis | shaft 5 Rotating body 7 Yoke 9 1st magnetic pole 11 Center magnetic pole 13 2nd magnetic pole 15 Rotating body accommodation hole 17 1st excitation means 19 2nd excitation means 25 Lens barrel 27 1st Reducer gear 29 Reducer gear 31 Second reducer gear 33 Output shaft 35 Plate cam 37 Support portion 39 Rotor kana 41 Coil springs 42a to 42d Bending portion 43 Optical axis 51 Electrical connection portion 61a, 61b Screw hole

Claims (2)

A cylindrical lens barrel that houses the lens;
A step motor for moving the lens barrel in the optical axis direction of the lens,
The step motor is
A rotating body magnetized in two poles in a direction perpendicular to the rotating body axis;
A first excitation means and a second excitation means for driving the rotating body rotatably;
A yoke that magnetically connects the rotating body and the first and second excitation means,
The rotating body and the first and second excitation means arranged so that the longitudinal direction thereof is the optical axis direction of the lens are respectively disposed along the outer periphery of the cylindrical lens barrel. A camera module characterized by The yoke forms a magnetic circuit for returning the magnetic flux generated by the first excitation means to the first excitation means via the first magnetic pole, the rotating body, and the central magnetic pole, and the second A magnetic circuit is formed to return the magnetic flux generated by the exciting means to the second exciting means via the second magnetic pole, the rotating body, and the central magnetic pole. The camera module according to claim 1.

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