JP3038622B2 - Lens drive mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens driving mechanism used for a video camera, a still camera and the like.

[0002]

2. Description of the Related Art In recent years, there has been a strong demand for downsizing and high performance / high performance cameras. In particular, needs for zoom speed, autofocus speed / accuracy, noise reduction, and low power consumption are particularly strong in video cameras. The lens drive mechanism of a camera needs to respond to these needs. Conventionally, as a lens driving mechanism, a method of moving a zoom lens and a focus lens in the optical axis direction by using a stepping motor or a DC motor to reduce gears, and further, to change the rotation operation of the motor into linear motion, has been widely adopted. I have. On the other hand, in a disk device such as a compact disk (CD), a direct drive system for generating linear motion by combining a plate magnet and a movable coil has been conventionally proposed for performing high-speed tracking.

FIG. 23 is a front view of a lens drive mechanism in an example to which a direct drive system is applied, FIG. 24 is a cross sectional view thereof, and FIG. 25 is a plan view thereof. 23 to 25, a lens moving frame 32 integrally formed with a lens 30 on an optical axis 31 is provided with a first bearing on two guide shafts 20a and 20b arranged vertically with the optical axis 31 interposed therebetween. It is slidably supported in the direction of the optical axis 31, that is, in the axial direction of the guide shafts 20a and 20b, via the portions 10a and 10b and the second bearing portion 11. The first bearing portions 10a and 10b are two cylindrical sliding bearings that fit into the guide shaft 20a with a predetermined gap therebetween. As shown in FIG. 23, the second bearing 11 is a slide bearing that also serves to restrict the rotation of the lens moving frame 32 in a plane perpendicular to the guide shafts 20a and 20b. The bearings are fixedly lubricated with polytetrafluoroethylene (PTFE), molybdenum disulfide, or the like in order to reduce frictional resistance and avoid the effects of temperature changes. When oil or grease is used, the frictional coefficient significantly increases under a light load like the mover in the present embodiment due to the adhesive force between the lubricant molecules, and the viscosity of the lubricant also increases. Are easily affected by the temperature, and the coefficient of friction may exceed 1 at a low temperature. The lens moving frame 32 is provided with the first bearings 10a and 10a as shown in FIG.
The configuration is such that the lens 30 is disposed substantially near the center of b. A substantially rectangular drive coil 7 is fixed to the lens moving frame 32 by bonding or the like. The drive coil 7 is disposed around the first bearing 10a, and its conductor is wound around the first bearing 10a. Further, permanent magnets 1a and 1b are fixed around the drive coil 7 to back yokes 4a and 4b provided on a lens barrel member (not shown). The back yoke 4a, 4b has a U-shaped cross section as shown in FIG. 25, and has an integral shape with the main yokes 3a, 3b. The main yokes 3a, 3b are opposed to the permanent magnets 1a, 1b via a predetermined gap. FIG. 23 shows a line connecting the centers of the surfaces of the main yokes 3a and 3b facing the magnetic pole surfaces of the permanent magnets 1a and 1b and a line connecting the centers of the magnetic pole surfaces of the permanent magnets 1a and 1b. And on the same plane H. The drive coil 7 includes the main yoke 3a,
3b and the permanent magnets 1a and 1b. Further, the main yokes 3a, 3b and the back yoke 4a,
Flat plate-shaped magnetic short member 6 for shorting the magnetic path of 4b
a and 6b are detachably attached. Permanent magnet 1
Reference numerals a and 1b denote plane-symmetric positions with respect to a plane K including the two guide shafts 20a and 20b, and their pole faces are arranged so as to be parallel to the plane K, and the pole faces are the same. A static magnetic field is formed with the polarities facing each other. The operation of the conventional lens driving mechanism configured as described above will be described. Drive coil 7 fixed to lens moving frame 32
, A propulsive force to move in the direction of the optical axis 31 between the permanent magnets 1a and 1b is received by Fleming's left-hand rule. In this manner, the present configuration can be directly driven, and does not involve a deceleration mechanism or the like, so that the lens moving frame 32 can be driven at high speed with low noise and low power consumption.

[0004]

However, the above configuration has the following problems. First, when a rotary motor such as a stepping motor or a DC motor is employed, the number of rotations of the motor must be greatly increased in order to improve the lens moving speed. In this case, it is impossible to cope with the situation without increasing the volume of the motor. However, increasing the rotation speed of the motor increases motor noise and power consumption. In the case of a microlens that vibrates at a high frequency, such as a focus lens, the moment of inertia of the motor suffers, resulting in poor response and positioning accuracy. Also deteriorates. On the other hand, in the examples shown in FIGS. 23, 24 and 25, high-speed driving is possible,
There is an advantage that low noise and low power consumption can be achieved, but the first bearings 10a and 10b and the guide shaft 20a
26, when the lens 30 reciprocates, as shown in FIG. 26, the play becomes unstable due to backlash, and there is a problem that the optical axis 31 greatly varies depending on the direction of movement. Similarly, when the gap between the second bearing 11 and the guide shaft 20b is large, as shown in FIG.
With the guide shaft 20a as the center of rotation, the guide shaft 20b rotates by the play of the play. In order to eliminate the influence of the play, it is necessary to equalize the linear expansion coefficients of the materials forming the guide shafts 20a and 20b and the first bearing portions 10a and 10b and the second bearing portion 11 and to increase the processing accuracy. However, the guide shafts 20a and 20b are generally high in accuracy because the material is polished and applied to a silicon unidirectional switch (SUS) material, but the first bearing portions 10a and 10b are high in accuracy.
Is difficult to achieve accuracy because of the inner diameter machining. In general, brass or resin material is used as the material of the bearing, but since the linear expansion coefficient is larger than SUS, even if the play is small at room temperature, the play becomes large or the temperature becomes low at high temperatures. Occasionally, an interference may occur and the lens moving frame may not move.

Further, as shown in FIG. 28, when the attitude of the camera as a whole changes, the frictional force between the guide shaft 20a and the first bearings 10a and 10b is significantly increased due to squeezing as compared with when the camera is in a horizontal state. Sometimes. In video cameras and the like, a method is known in which a focus lens is slightly vibrated by several tens of μm in the direction of the optical axis 31 at a high frequency so as to maximize the high frequency component of a video signal captured by an image sensor, and a focus position is searched. However, for that purpose, the lens 30 needs to follow the current applied to the drive coil 7. However, when the frictional force is significantly increased, the movement of the lens 30 is delayed with respect to the drive current applied to the drive coil 7, and when the frictional force is significantly increased, the drive control of the lens moving frame 32 becomes unstable. As a result, a situation may occur in which micro vibration cannot be performed. This will be described below. Here, taking the end point of the first bearing portion 10a as a reference in the XY coordinate system,
The X and Y axes are set as shown in FIG. Then, the lens moving frame 32, lens 30, X-direction center-of-gravity position X _W of the mover comprising including driving coil 7 will be present between the center of gravity of the driving coil 7, and the center of gravity of the lens 30. The Y-direction gravity center position Y _W of the mover is present between the optical axis 31 and the guide shaft 20a. On the other hand, the permanent magnets 1 of the main yokes 3a, 3b
A line segment connecting the centers of the surfaces facing the magnetic pole surfaces of a and 1b and a line segment connecting the centers of the magnetic pole surfaces of the permanent magnets 1a and 1b are on the same plane H. The intersection point of the plane H and the plane K including the two guide shafts 20a and 20b, that is, the thrust center of gravity position P of the actuator portion is located outside the axis of the guide shaft 20a. FIGS. 29, 30, and 31 show the calculation results of the frictional force when the camera is tilted in such a state. For simplicity of calculation, the lens moving frame 32 and the whole of the members fixed thereto are balanced in the left-right direction in FIG. 23 so that no side pressure is generated in the second bearing 11, and the guide shaft is Plane K including 20a and 20b
Assumes that there is no tilt in the left-right direction. Further, the coefficient of friction is always constant without depending on the attitude difference and the reaction force from the guide shaft 20a. Further, it is assumed that the axes of the first bearing portions 10a and 10b are completely aligned. 29, 30, and 31, the horizontal axis is the inclination angle θ of the guide shafts 20a and 20b. The vertical axis represents the thrust required to drive the mover. The thin solid line Fr in FIG.
At 8

[0006]

[Outside 1]

[0007] The sum of the frictional force and the component force of the mover weight in the direction of gravity. If the component of the weight of the mover in the gravitational direction is equal to or less than the thrust of the actuator, it completely follows the drive current applied to the drive coil 7, so that there is no problem in control. However, the component of the frictional force has a phase lag, which causes a problem in control. Since the gravity direction component can be represented by F, the frictional force Ff is obtained by subtracting F from Fr and is represented by a thick solid line in the drawing. The calculation parameters in FIGS. 29, 30, and 31 were set as follows. First, what is common to FIGS. 29, 30 and 31 is L _O : bearing span 16 mm Y _W : center of gravity in the Y direction 7 mm W: mass of mover 4 g D: guide shaft diameter 1.5 mm μ: coefficient of friction 0.25. On the other hand, each of the order that is changed with respect to FIG. 29, 30, 31, X _W: X-direction center-of-gravity position 4,4,8mm Y _P: thrust centroid 3 is -0.5,3Mm. As shown in FIG. 29, the frictional force Ff is 9.5 in a horizontal state.
It is mN, but reaches 1.36 times when the attitude is tilted about -70 degrees. When the frictional force Ff increases as described above, there is a possibility that the control becomes unstable. FIG. 30 shows the thrust center of gravity P closer to the optical axis 31. In this case, the frictional force Ff
Is only 9.8mN in the horizontal state, and does not exceed this even if the posture changes. FIG. 31 shows an example in which the position of the center of gravity X _{W in the} X direction is set at the center of the bearing span L _O with respect to the one shown in FIG. 29. In this case, the increase in the frictional force Ff is smaller than the result in FIG. It is suppressed and reduced to 1.26 times.

[0008] or this way the thrust center of gravity P of the optical axis 31 closer, by setting the X-direction center-of-gravity position X _W in the vicinity of the center of the bearing span L _O, it is possible to suppress an increase in the frictional force Ff . However, actually setting the thrust center of gravity P near the optical axis 31 is based on a conventional method in which a line segment connecting the centers of the magnetic poles of the permanent magnets 1a and 1b and the centers of the main yokes 4a and 4b exists on the same plane H. Then, it is often difficult to set the lens drive mechanism in order to reduce its size. The lens 30 first bearing portion 10a, to set in the vicinity of the center of 10b, and sets the direction of the optical axis center-of-gravity position X _W of considering the driving coil 7 mover first bearing portion 10a, the center of 10b Is extremely difficult to design the lens moving frame 32. Even if this is possible, for example, the bearing span L _O becomes large, and as a result, the whole lens driving mechanism becomes large. In order to cope with the above-mentioned phenomenon, it is conceivable that the bearing portion is composed of a bearing material having a small friction coefficient from the beginning, but such a material is likely to be extremely expensive in practice when considering solid lubrication. Even if such a material is used, when the humidity increases, the coefficient of friction significantly increases due to the presence of adhesion between water molecules under a light load. It becomes meaningless in equipment used in harsh environments.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and solves the above-mentioned problems by the following means.

A first technical means is that a lens moving frame is supported by two guide shafts, and a pair of permanent magnets and a yoke member constituting a magnetic circuit are arranged so as to sandwich one guide shaft, In addition, one of the permanent magnet and the yoke member is biased toward the optical axis, and the magnetic flux linked to the drive coil is biased toward the optical axis. As a result, the thrust center of gravity is biased toward the optical axis. A second technical means is that the lens moving frame is supported by two guide shafts, and a pair of first permanent magnets and a yoke member constituting a magnetic circuit are arranged so as to sandwich one guide shaft, In addition, with the addition of the magnetic circuit, the line segment connecting the centers of the magnetic poles of the pair of first permanent magnets is further away from the optical axis than the intersection of the second plane including the two guide shafts. A second permanent magnet having a magnetic pole surface at a position where the magnetic flux is generated from the first permanent magnet and weakening a magnetic flux component interlinking the drive coil is provided. The intersecting magnetic flux is deviated toward the optical axis, and as a result, the thrust center of gravity is deviated toward the optical axis. A third technical means is that a lens moving frame is supported by two guide shafts, and a pair of permanent magnets and a yoke member constituting a magnetic circuit are arranged so as to sandwich one of the guide shafts. In addition to the circuit, the superconducting member is located further away from the optical axis than an intersection of a line connecting the magnetic pole centers of the pair of permanent magnets and a second plane including the two guide shafts. By weakening the magnetic flux component generated from the permanent magnet and linked to the drive coil by the Meissner effect of the superconducting member, the magnetic flux linked to the drive coil is deflected to the optical axis side. The thrust center of gravity is deviated toward the optical axis. A fourth technical means is that a lens moving frame is supported by two guide shafts, and a pair of permanent magnets and a yoke member constituting a magnetic circuit are arranged so as to sandwich one of the guide shafts. The center of gravity in the optical axis direction is biased toward one end of the bearing, and the center of gravity in the optical axis direction of the drive coil is biased toward the other end of the bearing. The position of the center of gravity in the axial direction is substantially coincident with the center of the first bearing portion. A fifth technical means is that a lens moving frame is supported by two guide shafts, a pair of permanent magnets and a yoke member constituting a magnetic circuit are arranged so as to sandwich one of the guide shafts, and a drive coil is provided. By disposing an attraction member made of a magnetic material integrally formed in close proximity to either one of the pair of permanent magnets, the play caused by the gap between the bearing portion and the guide shaft is canceled, and the bearing is always provided with the bearing. The sliding position with the guide shaft is the same so that the lens posture is stabilized.

[0011]

The operation of the first technical means is as follows. That is, as described above, one of the permanent magnet and the yoke member is deflected toward the optical axis, and the magnetic flux linked to the drive coil is deflected toward the optical axis. As a result, the thrust center of gravity is deflected toward the optical axis. As a result, an increase in frictional force can be eliminated, controllability is improved, and even a bearing material having a relatively large friction coefficient can be used. The operation of the second technical means is as follows. That is, as described above, by providing the second permanent magnet that generates a magnetic flux component generated from the first permanent magnet and weakening the magnetic flux component linked to the drive coil, the magnetic flux linked to the drive coil is reduced. By shifting the thrust center of gravity toward the optical axis as a result of biasing toward the optical axis, it is possible to eliminate an increase in frictional force, improve controllability, and provide a relatively large friction coefficient bearing material. Can also be used. The third
The effect of the technical means is as follows. That is,
As described above, the superconducting member is provided, and the Meissner effect of the superconducting member weakens the magnetic flux component generated from the permanent magnet and interlinking the drive coil, thereby changing the magnetic flux interlinking the drive coil to the optical axis. By shifting the thrust center of gravity toward the optical axis side, it is possible to eliminate the increase in frictional force, improve controllability, and use even bearing materials with a relatively large friction coefficient. It becomes possible to do.
The operation of the fourth technical means is as follows. That is, as described above, the position of the center of gravity in the optical axis direction of the lens is biased toward one end of the bearing, and the position of the center of gravity in the optical axis direction of the drive coil is biased toward the other end of the bearing. By aligning the axial center of gravity of the integrally formed member with the center of the first bearing portion, an increase in frictional force can be suppressed, controllability is improved, and the friction coefficient is reduced. Even relatively large bearing materials can be used. The operation of the fifth technical means is as follows. That is, as described above, by disposing the magnetic material attraction member integrally formed with the drive coil close to one of the pair of permanent magnets, the gap between the bearing portion and the guide shaft is increased. It is possible to stabilize the lens posture by canceling the backlash and always making the location of the impulse between the bearing and the guide shaft the same.

[0012]

Embodiments of the first invention will be described with reference to the drawings. A detailed description of the same points as those in the conventional embodiment will be omitted. FIG. 1 is a front view of a lens driving mechanism according to a first embodiment of the present invention, FIG. 2 is a transverse sectional view thereof, and FIG. 3 is a plan view thereof. In FIG. 1, an intersection Pm of a line Hm connecting the centers of the magnetic pole surfaces of the permanent magnets 1a and 1b with a plane K including the two guide shafts 20a and 20b is closer to the optical axis 31 than the axis of the guide line 20a. Is bizarre. The gap δ1 between the drive coil 7 and the permanent magnets 1a, 1b is set slightly smaller than the gap δ2 between the main yokes 3a, 3b, so that the drive coil 7 is close to the permanent magnets 1a, 1b. , 1b. The operation and action of the lens driving mechanism of the present embodiment configured as described above will be described below. Permanent magnet 1
As shown in FIG. 1, the magnetic flux Φ leaks from a and 1b and is linked to the drive coil 7. Here, the permanent magnets 1a and 1b are optical axes.
Since the magnetic flux Φ is uneven to the side 31, the distribution of the magnetic flux Φ becomes non-uniform, and the magnetic flux Φ linked to the drive coil 7 is entirely on the optical axis 31.
The distribution will be shifted to the side. Therefore, the driving coil 7
The thrust center of gravity of the thrust generated in step (1) is also biased toward the optical axis 31 and almost coincides with the point Pm. Accordingly, the optical axis thrust centroid 31
It becomes possible to make the side largely biased. Therefore, FIG.
Score and becomes possible without an increase in the frictional force Ff as shown in, it is possible to improve the controllability becomes better without employing the bearing material resulting low coefficient of friction, it can reduce the cost become.

Next, a second embodiment will be described. FIG.
FIG. 9 is a front view of a lens driving mechanism according to a second embodiment of the present invention. In FIG. 4, an intersection P between a line segment Hy connecting the centers of the surfaces of the main yokes 3a and 3b facing the magnetic pole surfaces of the permanent magnets 1a and 1b and a plane K including the two guide shafts 20a and 20b.
y is deviated more toward the optical axis 31 than the axis of the guide shaft 20a. The gap δ1 between the drive coil 7 and the permanent magnets 1a, 1b
Is set slightly larger than the gap δ2 between the main yokes 3a and 3b so that the drive coil 7 is closer to the main yokes 3a and 3b, and is strongly affected by the magnetic flux Φ near the main yokes 3a and 3b. is there. The operation and action of the lens driving mechanism of the present embodiment configured as described above will be described below. As shown in FIG. 4, the magnetic flux Φ leaks from the permanent magnets 1 a and 1 b and links with the drive coil 7. Here, since the main yokes 3a and 3b are deviated toward the optical axis 31,
The distribution of the magnetic flux Φ becomes non-uniform, and the magnetic flux Φ linked to the drive coil 7 is disproportionately distributed toward the optical axis 31 as a whole. Therefore, the thrust center of gravity of the thrust generated by the drive coil 7 substantially coincides with the point Py. Therefore, it is possible to deviate significantly thrust centroid to the optical axis 31. Thus enables the score without an increase in the frictional force Ff as shown in FIG. 30, it is possible to improve the controllability becomes better without employing the bearing material resulting low coefficient of friction, the cost It becomes possible to plan.

Next, a third embodiment will be described. FIG.
FIG. 9 is a front view of a lens driving mechanism according to a third embodiment of the present invention. Permanent magnets 1a and 1b are integrally formed on the lens moving frame 32 via back yokes 4a and 4b. The back yokes 4a, 4b have a U-shaped cross section (not shown), and are integral with the main yokes 3a, 3b. The main yokes 3a, 3b are opposed to the permanent magnets 1a, 1b via a predetermined gap. The intersection Py between the line segment Hy connecting the centers of the surfaces of the main yokes 3a and 3b facing the magnetic pole surfaces of the permanent magnets 1a and 1b and the plane K including the two guide shafts 20a and 20b is the axis of the guide shaft 20a. It is more deviated toward the optical axis 31 than the core. The polarities of the permanent magnets 1a, 1b fixed to the back yokes 4a, 4b are set to be the same.
Further, a flat magnetic short-circuit member (not shown) for short-circuiting the magnetic path between the main yokes 3a, 3b and the back yokes 4a, 4b is detachably attached. On the other hand, a drive coil 7 having a substantially rectangular shape is fixed to a lens barrel member (not shown). The drive coil 7 is disposed around the first bearing 10a, and its conductor is wound around the first bearing 10a. The drive coil 7 is connected to the main yoke 3a,
3b and the permanent magnets 1a and 1b. The gap δ2 between the drive coil 7 and the permanent magnets 1a and 1b
Is set slightly larger than the gap δ1 between the main yokes 3a and 3b so that the drive coil 7 is closer to the main yokes 3a and 3b, and is strongly affected by the magnetic flux Φ near the main yokes 3a and 3b. is there. The operation and action of the lens driving mechanism of the present embodiment configured as described above will be described below. As shown in FIG. 5, the magnetic flux Φ leaks from the permanent magnets 1a and 1b and is linked to the drive coil 7. Here, since the main yokes 3a and 3b are deviated toward the optical axis 31,
The distribution of the magnetic flux Φ becomes non-uniform, and the magnetic flux Φ linked to the drive coil 7 is disproportionately distributed toward the optical axis 31 as a whole. Therefore, the thrust center of gravity of the thrust generated by the drive coil 7 substantially coincides with the point Py. Therefore, in the present embodiment, a line segment H connecting the center points of the permanent magnets 1a and 1b.
Although m exists outside the optical axis 31 with respect to the guide shaft 20a, the thrust center of gravity can be biased toward the optical axis 31 near the point Py. Therefore, as shown in FIG. 30, it is possible to eliminate the increase in the frictional force Ff, and to improve the controllability. As a result, it is not necessary to use a bearing material having a low friction coefficient, and the cost can be reduced. It becomes possible to plan. In this embodiment, the intersection Py between the line segment Hy connecting the centers of the main yokes 3a and 3b and the plane K is set so as to be closer to the optical axis 31, but as in the first embodiment, it is permanent. The line Hm connecting the centers of the magnets 1a and 1b is the optical axis.
It may be set to be on the 31st side.

Next, a fourth embodiment will be described. FIG.
FIG. 11 is a front view of a lens driving mechanism according to a fourth embodiment of the present invention. In the first to third embodiments, the permanent magnet 1
Although a and 1b were fixed to the back yoke, in this embodiment, in order to reduce the size of the actuator and the number of components, the permanent magnet is attached to the end face in the direction of the optical axis 31 without using the back yoke member. And is fixed to a lens barrel member (not shown) by bonding or the like. Here, the plane K including the two guide shafts 20a and 20b of the line segment Hy that connects the center of the object surfaces with the magnetic pole surfaces of the permanent magnets 1a and 1b of the main yokes 3a and 3b is an intersection Py.
Is deviated toward the optical axis 31 from the axis of the guide shaft 20a.
The gap δ1 between the drive coil 7 and the permanent magnets 1a and 1b is
The gap is set to be slightly larger than the gap δ2 between the main yokes 3a and 3b, the drive coil 7 is made closer to the main yokes 3a and 3b, and is strongly affected by the magnetic flux Φ near the main yokes 3a and 3b. The operation and action of the lens driving mechanism of the present embodiment configured as described above will be described below. From the permanent magnets 1a and 1b, as shown in FIG.
The magnetic flux Φ leaks and links the drive coil 7. Here, since the main yokes 3a and 3b are deviated toward the optical axis 31, the distribution of the magnetic flux Φ becomes non-uniform, and the thrust centroid of the thrust generated by the drive coil 7 substantially coincides with the point Py. Therefore, in this embodiment, the thrust barycenter is pointed toward the optical axis 31 side even though the line segment Hm connecting the center points of the permanent magnets 1a and 1b exists outside the optical axis 31 with respect to the guide shaft 20a. Py
It becomes possible to deviate to the vicinity. Therefore, as shown in FIG. 30, it is possible to eliminate the increase in the frictional force Ff, and to improve the controllability. As a result, it is not necessary to use a bearing material having a low friction coefficient, and the cost can be reduced. It becomes possible to plan. In this embodiment, the intersection Py between the line segment Hy connecting the centers of the main yokes 3a and 3b and the plane K is set so as to be closer to the optical axis 31.
As in the embodiment, the line segment Hm connecting the centers of the permanent magnets 1a and 1b may be set to be on the optical axis 31 side.

Next, a fifth embodiment will be described. FIG.
FIG. 14 is a front view of a lens driving mechanism according to a fifth embodiment of the present invention. In the first to third embodiments, the permanent magnet 1
Although a and 1b are set so that the polarities of the magnetic pole surfaces fixed to the back yokes 4a and 4b are the same, in this embodiment,
They are set to be opposite to each other. Here, the intersection point Pm of the line segment Hm that connects the centers of the magnetic pole surfaces of the permanent magnets 1a and 1b with the plane K including the two guide shafts 20a and 20b is the guide shaft 20.
It is deviated toward the optical axis 31 side from the axis of a. In addition, two are provided corresponding to the drive coil 7 and the permanent magnets 1a and 1b. However, the directions in which the current applied to the drive coil 7 flows are set to be opposite to each other. The drive coil 7
The gap δ1 between the main yoke 3 and the permanent magnets 1a and 1b
a, 3b are set slightly smaller than the gap δ2 between the permanent magnets 1a, 1b.
It is designed to be strongly affected by the magnetic flux Φ near a and 1b. The operation and action of the lens driving mechanism of the present embodiment configured as described above will be described below. Permanent magnets 1a, 1b
7, the magnetic flux Φ leaks and interlinks with the drive coil 7, as shown in FIG. Here, since the permanent magnets 1a and 1b are deviated toward the optical axis 31, the distribution of the magnetic flux Φ becomes non-uniform, and the thrust centroid of the thrust generated by the drive coil 7 substantially matches the point Pm. Therefore, in this embodiment, the line segment Hy connecting the centers of the main yokes 3a and 3b is formed by the guide shaft 20.
Despite being outside the optical axis 31 with respect to a, the center of gravity of the thrust can be biased near the point Pm on the optical axis 31 side. Therefore, as shown in FIG. 30, it is possible to eliminate an increase in the frictional force Ff, thereby improving controllability.
As a result, it is not necessary to use a bearing material having a low friction coefficient, and cost can be reduced. In this embodiment, a line segment H connecting the centers of the permanent magnets 1a and 1b is used.
The intersection point Pm between the m and the plane K is set so as to be closer to the optical axis 31, but a line segment H connecting the centers of the main yokes 3a and 3b.
y may be set to be on the optical axis 31 side.

Next, a sixth embodiment will be described. FIG.
FIG. 14 is a front view of a lens driving mechanism according to a sixth embodiment of the present invention. Permanent magnets 1a and 1b are integrally formed on the lens moving frame 32 via back yokes 4a and 4b. The back yokes 4a, 4b have a U-shaped cross section (not shown), and are integral with the main yokes 3a, 3b. The main yokes 3a, 3b are opposed to the permanent magnets 1a, 1b via a predetermined gap. The intersection point Pm between the line segment Hm connecting the centers of the magnetic pole faces of the permanent magnets 1a and 1b and the plane K including the two guide shafts 20a and 20b is closer to the guide shaft 20a by the optical axis 31 than the axis.
Is bizarre to the side. The polarities of the permanent magnets 1a and 1b fixed to the back yokes 4a and 4b are set to be opposite to each other. Further, a flat magnetic short-circuit member (not shown) for short-circuiting the magnetic path between the main yokes 3a, 3b and the back yokes 4a, 4b is detachably attached.
On the other hand, two substantially rectangular drive coils 7 are fixed to a lens barrel member (not shown) corresponding to the permanent magnets 1a and 1b. However, the directions in which the current applied to the drive coil 7 flows are set to be opposite to each other. The drive coil 7 is fitted in a space defined by the main yokes 3a, 3b and the permanent magnets 1a, 1b. The drive coil 7 and the permanent magnet 1
The gap δ1 with the main yoke 3a, 3b is set slightly smaller than the gap δ2 with the main yokes 3a, 3b.
a, 1b so as to be strongly affected by the magnetic flux Φ near the permanent magnets 1a, 1b. The operation and action of the lens driving mechanism of the present embodiment configured as described above will be described below. As shown in FIG. 8, the magnetic flux Φ leaks from the permanent magnets 1a and 1b and is linked to the drive coil 7.
Here, since the permanent magnets 1a and 1b are deviated toward the optical axis 31, the distribution of the magnetic flux Φ becomes non-uniform, and the thrust centroid of the thrust generated by the drive coil 7 substantially matches the point Pm. Therefore, in this embodiment, the main yoke 3a,
The line segment Hy connecting the centers of 3b is the optical axis with respect to the guide axis 20a.
Despite being outside of 31, the thrust center of gravity is
It can be biased to the vicinity of the side point Pm. Therefore, as shown in FIG. 30, it is possible to eliminate the increase in the frictional force Ff, and to improve the controllability. As a result, it is not necessary to use a bearing material having a low friction coefficient, and the cost is reduced. It becomes possible. In this embodiment, the intersection P between the line Hy connecting the centers of the main yokes 3a and 3b and the plane K is set to be closer to the optical axis 31, but the line connecting the centers of the permanent magnets 1a and 1b. The minute may be set to be on the optical axis 31 side. Although the magnetic circuit is arranged around the guide shaft 20a in the first to sixth embodiments, it may be arranged around the guide shaft 20b. As described above, one of the permanent magnets 1a, 1b and the main yokes 3a, 3b is connected to the optical axis.
Deflected to the 31 side, the magnetic flux Φ linked to the drive coil
By shifting the thrust center of gravity toward the optical axis 31 as a result, the increase in frictional force can be eliminated, controllability is improved, and the bearing material has a relatively large friction coefficient. Can also be used.

Next, an embodiment of the second invention will be described. A detailed description of the same points as those in the conventional embodiment will be omitted. FIG. 9 is a front view of the lens driving mechanism according to the first embodiment of the present invention, and FIG. 10 is a cross-sectional view thereof. In FIG. 9, a pair of first permanent magnets 1a and 1b are guide shafts.
It is arranged around 20a, and its magnetic pole face is parallel to a plane K including two guide shafts 20a and 20b. The polarities of the magnetic pole surfaces fixed to the back yokes 4a and 4b are set to be the same. A line H connecting the centers of the magnetic poles of the pair of first permanent magnets 1a and 1b.
and a magnetic flux component that has a magnetic pole surface at a position more distant from the optical axis 31 than an intersection Pm between the m and the plane K, and weakens a magnetic flux component generated from the first permanent magnet and linked to the drive coil. The generated second permanent magnet 1c is provided. Therefore, the polarity of the magnetic pole surface fixed to the back yoke 4c of the second permanent magnet 1c is set to be opposite to that of the permanent magnets 1a and 1b. Also, the first permanent magnets 1a, 1b
The permanent magnet 1c has a low energy product, such as a ferrite magnet, while the magnet used in Example 1 has a high energy product like a rare earth magnet. The operation and operation of the lens driving mechanism of the present embodiment configured as described above will be described below. As shown in FIG. 9, the magnetic flux Φ leaks from the permanent magnets 1a, 1b, 1c and links with the drive coil 7. Here, a thrust is generated between the first permanent magnets 1a and 1b and the drive coil 7, and the thrust center of gravity coincides with the point Pm. On the other hand, since the second permanent magnet 1c is present, a thrust is generated in a direction opposite to that by the first permanent magnets 1a and 1b. Therefore, in this embodiment, the permanent magnets 1a, 1b
A line segment Hm connecting the center points of the optical axes 3 to the guide axis 20a
Despite being outside of 1, the total thrust center of gravity of the first and second permanent magnets 1a, 1b, 1c can be deviated toward the optical axis 31 side. As a result, as shown in FIG. 30, an increase in the frictional force Ff can be eliminated, controllability can be improved, and as a result, it is not necessary to use a bearing material having a low friction coefficient, and cost can be reduced. It becomes possible to plan.

In this embodiment, the second permanent magnet 1
Although only the back yoke 4c was provided with respect to c and the main yoke member was not arranged, a second embodiment of the present invention is shown in FIGS. A back yoke 4c formed in a letter shape and integrated with the main yoke 3c may be used. In this case, it is possible to further reduce the volume of the second permanent magnet 1c. Also, the back yoke 4c necessarily fixed to the second permanent magnet 1c
Is not necessary, and the second permanent magnet 1c is a lens barrel member.
(Not shown). In this case, the size of the second permanent magnet 1c is slightly increased, but the number of parts can be reduced. Similarly, the first permanent magnets 1a, 1b
As shown in FIG. 13, the back yokes 4a and 4b are not always necessary as the third embodiment of the present invention, and the first permanent magnets 1a and 1b are attached to a lens barrel member (not shown). It may be fixed directly. In this case, the first permanent magnets 1a, 1b
Is slightly larger, but the number of parts can be reduced. In addition, the material is changed between the first permanent magnets 1a and 1b and the second permanent magnet 1c. However, the material is not limited to this. It may be smaller than 1a and 1b. Further, the shape and dimensions of the second permanent magnet 1c are exactly the same as those of the first permanent magnets 1a and 1b, and the number of main yokes corresponding to the second permanent magnet 1c is reduced as shown in the first embodiment.
In addition, a configuration may be adopted in which the gap between the second permanent magnet 1c and the drive coil 7 is set large.

Next, a fourth embodiment of the second invention will be described. A detailed description of the same points as those in the conventional embodiment will be omitted. FIG. 14 is a front view of a lens driving mechanism according to a fourth embodiment of the present invention. In FIG. 14, a pair of first
The permanent magnets 1a and 1b are disposed around the guide shaft 20a, and their magnetic pole faces are parallel to a plane K including the two guide shafts 20a and 20b. The polarities of the magnetic pole surfaces fixed to the back yokes 4a and 4b are set to be the same. This magnetic circuit is further added, and the magnetic pole is positioned further away from the optical axis 31 than an intersection Pm between the line Hm connecting the centers of the magnetic poles of the pair of first permanent magnets 1a and 1b and the plane K. A second permanent magnet 1c having a surface and generating a magnetic flux component generated from the first permanent magnet and weakening a magnetic flux component linked to the drive coil is provided. Therefore, the polarity of the magnetic pole surface fixed to the back yoke 4c of the second permanent magnet 1c is set to be the same as that of the permanent magnets 1a and 1b. The magnets used for the first permanent magnets 1a and 1b have a high energy product like a rare earth magnet, but the permanent magnet 1c has a low energy product like a ferrite magnet. The operation and operation of the lens driving mechanism of the present embodiment configured as described above will be described below. As shown in FIG. 14, the magnetic flux Φ leaks from the permanent magnets 1a, 1b, 1c and is linked to the drive coil 7. Here, a thrust is generated between the first permanent magnets 1a and 1b and the drive coil 7, and the thrust center of gravity coincides with the point Pm. On the other hand, since the second permanent magnet 1c exists, the first permanent magnet 1a,
Thrust will be generated in the opposite direction to that of 1b. Therefore, in the present embodiment, the line segment Hm connecting the center points of the permanent magnets 1a and 1b is located on the optical axis 31 with respect to the guide axis 20a.
, It is possible to deviate the total thrust center of gravity of the first and second permanent magnets 1a, 1b, 1c toward the optical axis 31 side. As a result, as shown in FIG. 30, it is possible to eliminate the increase in the frictional force Ff, and to improve the controllability. As a result, it is not necessary to use a bearing material having a low frictional coefficient, and the cost can be reduced. It becomes possible to plan. In the fourth embodiment of the present invention, only the back yoke 4c is provided for the second permanent magnet 1c.
As a fifth embodiment, the back yoke member 4c may not be provided as shown in FIG. Conversely, both the back yoke 4c and the main yoke member may be provided. Also the second
In the first to fifth embodiments of the present invention, the driving coil 7
Is fixed to the lens moving frame 32, but is not necessarily limited to this, and the first and second permanent magnets 1a, 1b, 1
The configuration may be such that c and the yoke member are fixed to the lens drive frame 32, and the drive coil 7 is fixed to a lens barrel member (not shown). Further, the first permanent magnets 1a, 1b are
The polarities of the magnetic pole faces fixed to 4b are set to be the same as each other. However, as shown in the fifth and sixth embodiments of the first invention, the polarities are set to be opposite to each other. The magnet is a pair of magnets 2 each corresponding to the first permanent magnets 1a and 1b.
Alternatively, the magnetic pole faces may be set so that the magnetic pole faces having opposite polarities face the drive coil 7. The first and second aspects of the second invention
Although the magnetic circuit is disposed around the guide shaft 20a in the embodiment, the magnetic circuit may be disposed around the guide shaft 20b.

Next, a first embodiment of the third invention will be described. A detailed description of the same points as those in the conventional embodiment will be omitted. FIG. 16 is a front view of the lens driving mechanism according to the first embodiment of the present invention, and FIG. 17 is a cross-sectional view thereof. Figure
In FIG. 16, a pair of permanent magnets 1a and 1b are disposed around a guide shaft 20a, and the pole faces thereof are two guide shafts 20a.
a, 20b so as to be parallel to the plane K. The polarities of the magnetic pole surfaces fixed to the back yokes 4a and 4b are set to be the same. Further, in addition to the magnetic circuit, a line segment Hm connecting the centers of the magnetic poles of the pair of permanent magnets 1a and 1b, and a magnetic pole surface at a position farther from the optical axis 31 than an intersection Pm with the plane K are provided. In addition, a superconducting member 40 is provided which partially eliminates a magnetic flux component generated from the first permanent magnet and linked to the drive coil by the Meissner effect. The operation and operation of the lens driving mechanism of the present embodiment configured as described above will be described below.
As shown in FIG. 16, the magnetic flux Φ leaks from the permanent magnets 1a and 1b and is linked to the drive coil 7. Here the drive coil 7
Due to the presence of the superconducting member 40, the center of gravity of the magnetic flux Φ linked to
The position is shifted more toward the optical axis 31 than m. Therefore, in this embodiment, the thrust center of gravity is located on the optical axis 31 side even though the line segment Hm connecting the center points of the permanent magnets 1a and 1b exists outside the optical axis 31 with respect to the guide shaft 20a. It becomes possible to skew. Therefore, as shown in FIG.
An increase in f can be eliminated, controllability can be improved, and as a result, it is not necessary to use a bearing material having a low coefficient of friction, and cost can be reduced.
Further, of the magnetic flux Φ generated from the permanent magnets 1a and 1b, it is possible to converge a component that does not link with the drive coil 7 so as to link with the drive coil 7, and the magnetic flux Φ from the permanent magnets 1a and 1b. Can be used more effectively. The position where the superconducting member 40 is disposed is not necessarily limited to the position shown in the present embodiment, but as the second embodiment of the present invention, as shown in FIG. The permanent magnets 1a and 1b may be integrally formed on a lens barrel (not shown). Here, even if the position where the superconducting member 40 is further disposed is brought closer to the guide shaft 20a side and the position is hidden from the permanent magnets 1a and 1b by the main yokes 3a and 3b,
When the main yokes 3a and 3b are magnetically saturated,
Similar effects can be expected. In the first and second embodiments, the drive coil 7 is fixed to the lens moving frame 32. However, the present invention is not limited to this.
The configuration may be such that a, 1b and the yoke member are fixed to the lens moving frame 32, and the drive coil 7 is fixed to the lens barrel member (not shown). Further, the permanent magnets 1a and 1b are used as back yokes 4a and 4b.
Although the polarities of the magnetic pole faces fixed to the first and second magnetic poles are made identical to each other, they may be made mutually opposite polarities as shown in the fifth and sixth embodiments of the first invention. Although the magnetic circuit is arranged around the guide shaft 20a in this embodiment,
It may be arranged around the guide shaft 20b. Also permanent magnet 1
Although the back yokes 4a and 4b are provided in a and 1b, they may be omitted.

Next, an embodiment of the fourth invention will be described. A detailed description of the same points as those in the conventional embodiment will be omitted. FIG. 19 is a cross-sectional view of the lens driving mechanism according to the embodiment of the present invention. In FIG. 19, the lens 30 is disposed at a position deviated near the first bearing portion 10a. In the lens moving frame 32, the drive coil 7 having a substantially rectangular shape is disposed at a position deviated near the first bearing portion 10b. Accordingly, as described above, the position of the center of gravity of the lens 30 in the direction of the optical axis 31 is biased toward the first bearing portion 10a, and the position of the center of gravity of the drive coil 7 in the direction of the optical axis 31 is biased toward the first bearing portion 10b. Accordingly, and integrally the axial center-of-gravity position X _W of the overall structure with members the first bearing portion 10a, is matched to the approximate center of 10b of the lens frame 32 and the lens frame 32. The operation and operation of the lens driving mechanism of the present embodiment configured as described above will be described below. Wherein the lens frame 32 and the lens frame 32 in the axial direction center-of-gravity position X _W of the entire members integrally formed first bearing portion 10a, by which is matched to the approximate center of 10b, and not necessarily the lens 30 the first bearing portion 10a , 10b, it is possible to suppress an increase in the frictional force Ff as shown in FIG. 31, thereby improving the controllability, and as a result, the movable state including the lens moving frame 32 is possible. The degree of freedom in the design of the child can be improved, and the size can be further reduced.
In this embodiment, the drive coil 7 is connected to the lens moving frame.
The permanent magnets 1a, 1b and the yoke member are fixed to the lens moving frame 32.
, And the drive coil 7 may be fixed to a lens barrel member (not shown). In this embodiment, the magnetic circuit is provided around the guide shaft 20a, but may be provided around the guide shaft 20b.

Finally, a first embodiment of the fifth invention will be described. A detailed description of the same points as in the conventional embodiment will be omitted. FIG. 20 is a front view of the lens driving mechanism according to the first embodiment of the present embodiment, and FIG. 21 is a plan view thereof. In FIG. 20, a pair of permanent magnets 1a and 1b are guide shafts.
It is arranged around 20a, and its magnetic pole face is parallel to a plane K including two guide shafts 20a and 20b. The polarities of the magnetic pole surfaces fixed to the back yokes 4a and 4b are set so that the same polarity is the same. Further, a rectangular magnetic material adsorbing member 41 integrally formed with the drive coil 7 is attached to the pair of permanent magnets 1a and 1b.
In this embodiment, any one of them is disposed close to the permanent magnet 1b. The operation and operation of the lens driving mechanism of the present embodiment configured as described above will be described below.
As shown in FIG. 20, the magnetic flux Φ leaks from the permanent magnets 1a and 1b, and the drive coil 7 is linked. Here, a part of the magnetic flux Φ also links with the attraction member 41, so that the attraction member 41 tries to attract to the permanent magnet 1b side. As a result, the lens frame 32 tends to rotate in the counterclockwise direction in the figure, and the guide shafts 20a, 20b, the first bearing portions 10a, 10b, and the second bearing portion 11 The contact surface always tries to be constant. Therefore, the guide shafts 20a, 20b and the first bearing portions 10a, 1
Even if the gap between 0b and the second bearing portion 11 becomes large, the movement of the lens 30 becomes unstable due to the play, and it is solved that the optical axis 31 largely fluctuates depending on the direction of movement. Therefore,
As the material of the lens frame 32, a material having a small coefficient of linear expansion does not have to be selected , and a general-purpose resin material can be sufficiently used. The shape of the suction member 41 is not limited to the one shown in FIG. 21. For example, a plurality of suction members 41 may be formed as shown in FIG. 22 as a second embodiment. Also, it is not limited to a rectangular flat plate. In addition, if the size and position of the suction member are appropriately set, the lateral pressure load and the eddy current loss of the bearing portion do not need to increase so much, so that the control at the time of minute vibration in the focusing operation does not become unstable. In the present embodiment, the drive coil 7 is fixed to the lens moving frame 32, but is not necessarily limited to this.
The permanent magnets 1a and 1b and the yoke member may be fixed to the lens moving frame 32, and the drive coil 7 may be fixed to a lens barrel member (not shown). Further, the polarities of the magnetic pole surfaces where the permanent magnets 1a, 1b are fixed to the back yokes 4a, 4b are the same as each other, but are opposite to each other as shown in the fifth and sixth embodiments of the first invention. Polarity may be used. In this embodiment, the magnetic circuit is provided around the guide shaft 20a, but may be provided around the guide shaft 20b. Although the permanent magnets 1a and 1b have the back yokes 4a and 4b, they may be omitted. Furthermore, in each of the first to fifth inventions, the first bearing portion is a bearing portion having two cylindrical shapes. However, the present invention is not limited to this, and one cylindrical bearing having a long axial distance. It is good. Further, the first bearing portions 10a and 10b and the second bearing portion 11 are resin molded products integral with the lens frame 32, but the present invention is not limited to this, and may be separate pieces.

[0024]

As apparent from the above, the present invention has the following effects. According to the lens driving mechanism of the first aspect, one of the permanent magnet and the yoke member is biased toward the optical axis, and the magnetic flux linked to the drive coil is biased toward the optical axis. By shifting the center of gravity toward the optical axis, an increase in frictional force can be eliminated, controllability is improved, and even a bearing material having a relatively large friction coefficient can be used. According to the lens driving mechanism according to the second aspect of the present invention, the drive is provided by disposing the second permanent magnet that generates a magnetic flux component generated from the first permanent magnet and weakening a magnetic flux component linked to the drive coil. The magnetic flux linked to the coil is deviated to the optical axis side, and as a result, the thrust center of gravity is deviated to the optical axis side, thereby eliminating the increase in frictional force, improving controllability, and comparing the friction coefficient. It is possible to use even large bearing materials. According to the lens driving mechanism of the third aspect, the superconducting member is disposed, and the Meissner effect of the superconducting member weakens a magnetic flux component generated from the permanent magnet and linked to the driving coil, thereby driving the lens. By deviating the magnetic flux linked to the coil to the optical axis side and consequently to deviating the thrust center of gravity to the optical axis side, it is possible to eliminate the increase in frictional force, improve controllability, and compare the friction coefficient. It is possible to use even large bearing materials. According to the lens drive mechanism of the fourth aspect, the center of gravity of the lens in the optical axis direction is biased toward one end of the bearing, and the center of gravity of the drive coil in the optical axis direction is biased toward the other end of the bearing. As a result, the axial center of gravity of the lens frame and the entire member integrally formed with the lens frame are substantially aligned with the center of the first bearing portion, whereby the degree of freedom in designing the lens frame is improved and the size is reduced. This makes it possible to suppress an increase in frictional force, improve controllability, and use a bearing material having a relatively large friction coefficient.

According to the lens drive mechanism of the fifth aspect, the magnetic material attraction member integrally formed with the drive coil is disposed close to one of the pair of permanent magnets. Thereby, the play caused by the gap between the bearing portion and the guide shaft is canceled, and the position of the impulse between the bearing and the guide shaft is always the same so that the lens posture can be stabilized.

[Brief description of the drawings]

FIG. 1 is a front view of a lens driving mechanism according to a first embodiment of the first invention.

FIG. 2 is a cross-sectional view of the lens driving mechanism in the embodiment.

FIG. 3 is a plan view of a lens driving mechanism in the embodiment.

FIG. 4 is a front view of a lens driving mechanism according to a second embodiment of the first invention.

FIG. 5 is a front view of a lens driving mechanism according to a third embodiment of the first invention.

FIG. 6 is a front view of a lens driving mechanism according to a fourth embodiment of the first invention.

FIG. 7 is a front view of a lens driving mechanism according to a fifth embodiment of the first invention.

FIG. 8 is a front view of a lens driving mechanism according to a sixth embodiment of the first invention.

FIG. 9 is a front view of a lens driving mechanism according to the first embodiment of the second invention.

FIG. 10 is a cross-sectional view of the lens driving mechanism in the embodiment.

FIG. 11 is a front view of a lens driving mechanism according to a second embodiment of the second invention.

FIG. 12 is a cross-sectional view of the lens driving mechanism in the same embodiment.

FIG. 13 is a front view of a lens driving mechanism according to a third embodiment of the second invention.

FIG. 14 is a front view of a lens driving mechanism according to a fourth embodiment of the second invention.

FIG. 15 is a front view of a lens driving mechanism according to a fifth embodiment of the second invention.

FIG. 16 is a front view of the lens driving mechanism according to the first embodiment of the third invention.

FIG. 17 is a cross-sectional view of the lens driving mechanism in the same embodiment.

FIG. 18 is a front view of a lens driving mechanism according to a second embodiment of the third invention.

FIG. 19 is a cross-sectional view of the lens driving mechanism according to the first embodiment of the fourth invention.

FIG. 20 is a front view of the lens driving mechanism according to the first embodiment of the fifth invention.

FIG. 21 is a plan view of a lens drive mechanism in the same embodiment.

FIG. 22 is a plan view of a lens driving mechanism according to a second embodiment of the fifth invention.

FIG. 23 is a front view of a lens driving mechanism in a conventional example.

FIG. 24 is a cross-sectional view of a lens driving mechanism in a conventional example.

FIG. 25 is a plan view of a lens driving mechanism in a conventional example.

FIG. 26 is a cross-sectional view showing a change in an optical axis when a lens driving mechanism in a conventional example is minutely vibrated.

FIG. 27 is a front view showing a fluctuation of an optical axis due to backlash of a lens driving mechanism in a conventional example.

FIG. 28 is a cross-sectional view showing a ridge of a bearing portion when a lens driving mechanism in a conventional example is inclined.

FIG. 29 is a diagram illustrating a relationship between an inclination angle and a frictional force when the lens driving mechanism is inclined.

FIG. 30 is a diagram illustrating a relationship between an inclination angle and a frictional force when the lens driving mechanism is inclined.

FIG. 31 is a diagram illustrating a relationship between an inclination angle and a frictional force when the lens driving mechanism is inclined.

[Explanation of symbols]

1a, 1b, 1c: permanent magnet, 3a, 3b, 3c: main yoke, 4a, 4b, 4c: back yoke, 6a, 6b ...
Magnetic short member, 7: drive coil, 10a, 10b: first bearing portion, 11: second bearing portion, 20a, 20b: guide shaft,
30 ... Lens, 31 ... Optical axis, 32 ... Lens moving frame, 40 ...
Superconducting members, 41 ... adsorption members.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G02B 7/04 G11B 7/09

Claims (5)

(57) [Claims] 1. A lens arranged on an optical axis, two guide shafts sandwiching the lens and arranged in parallel with the optical axis, and a first bearing fitted to one of the guide shafts Part, a second bearing part which engages with the other one of the two guide shafts, and also serves to restrict rotation in a first plane perpendicular to the guide shafts, and the two guides. Second comprising an axis
At the plane symmetrical position with respect to the plane of
A pair of permanent magnets that are parallel to the plane of and are disposed around one of the first and second bearing portions; and one of the permanent magnets that is integrally formed with the permanent magnets. A pair of yoke members opposed to each other with a predetermined gap between the magnetic pole surfaces and a gap between the yoke member and the permanent magnet.
A drive coil that generates thrust in the axial direction of the guide shaft;
Either the permanent magnet or the drive coil and the lens are integrally formed, and are slidably supported in the axial direction of the two guide shafts by the first and second bearings. A lens moving frame, a line segment connecting the magnetic pole centers of the permanent magnets, and the second
A second intersection between the first intersection with the plane and a line segment connecting the centers of the surfaces of the yoke members facing the permanent magnet, and a second intersection with the second plane are defined by the guide axis and the optical axis. Between the first intersection and the second intersection.
A lens drive mechanism disposed closer to the optical axis . 2. A lens arranged on an optical axis, and a lens arranged on both sides of the lens and parallel to the optical axis.
Two guide shafts, a first bearing portion fitted to one of the guide shafts, and engaged with the other guide shaft of the two guide shafts, in a first plane perpendicular to the guide shafts. The second that also controls the rotation of
And a magnetic pole surface parallel to the second plane at a position symmetrical with respect to a second plane including the two guide shafts, and the first and second bearings. A pair of permanent magnets disposed around one of the bearing portions of the first and the second permanent magnets;
A pair of yoke members disposed opposite to each other on one magnetic pole surface of the permanent magnet with a predetermined gap therebetween; and a pair of yoke members arranged in a gap between the yoke member and the first permanent magnet. And a drive coil that generates thrust in the axial direction of the two guide shafts, and a line segment that is integrally formed with the first permanent magnet and connects the magnetic pole centers of the pair of first permanent magnets. And a magnetic flux component having a magnetic pole surface at a position further away from the optical axis than the intersection with the second plane, and weakening a magnetic flux component generated from the first permanent magnet and linked to the drive coil. The second permanent magnet to be generated, any one of the first and second permanent magnets or the drive coil, and the lens are integrally formed, and the first and second bearings are used to form the second permanent magnet. A lens slidably supported in the axial direction of two guide shafts Lens driving mechanism, characterized by comprising a dynamic frame. 3. A lens arranged on the optical axis, and a lens arranged on both sides of the lens and parallel to the optical axis.
Two guide shafts, a first bearing portion fitted to one of the guide shafts, and engaged with the other guide shaft of the two guide shafts, in a first plane perpendicular to the guide shafts. The second that also controls the rotation of
And a magnetic pole surface parallel to the second plane at a position symmetrical with respect to a second plane including the two guide shafts, and the first and second bearings. A pair of permanent magnets disposed around one of the bearing portions, and a pair of permanent magnets integrally formed with the permanent magnet and disposed so as to face one magnetic pole surface of the permanent magnet with a predetermined gap therebetween. A drive coil disposed in a gap between the yoke member and the permanent magnet and generating a thrust in the axial direction of the two guide shafts between the yoke member and the permanent magnet when energized; A line segment connecting the magnetic pole centers of the pair of permanent magnets, and a member made of a superconducting material disposed at a position further away from the optical axis than an intersection with the second plane; Either the permanent magnet or the drive coil and the lens The integrally formed, the first, the second bearing portion, the two guide shafts lens driving mechanism, characterized in that the axial direction; and a slidably supported by the lens moving frame. 4. A lens disposed on an optical axis, and a lens disposed on both sides of the lens and parallel to the optical axis.
Two guide shafts, a first bearing portion fitted to one of the guide shafts, and engaged with the other guide shaft of the two guide shafts, in a first plane perpendicular to the guide shafts. The second that also controls the rotation of
And a magnetic pole surface parallel to the second plane at a position symmetrical with respect to a second plane including the two guide shafts, and the first and second bearings. A pair of permanent magnets disposed around one of the bearing portions, and a pair of permanent magnets integrally formed with the permanent magnet and disposed so as to face one magnetic pole surface of the permanent magnet with a predetermined gap therebetween. A drive coil disposed in a gap between the yoke member and the permanent magnet and generating a thrust in the axial direction of the two guide shafts between the yoke member and the permanent magnet when energized; Lens movement in which one of a magnet or the drive coil and the lens are integrally formed, and the first and second bearings are slidably supported in the axial direction of the two guide shafts. And a frame, and a center of gravity position of the lens in the axial direction. The first bearing portion is biased toward one end and the axial center of gravity of a member other than the lens integrally formed with the lens frame is biased toward the other end of the first bearing portion. A lens driving mechanism, wherein the position of the center of gravity in the axial direction of the lens frame and a member integrally formed with the lens frame is set substantially at the center of the first bearing portion. 5. A lens disposed on an optical axis, and a lens disposed on both sides of the lens and parallel to the optical axis.
Two guide shafts, a first bearing portion fitted to one of the guide shafts, and engaged with the other guide shaft of the two guide shafts, in a first plane perpendicular to the guide shafts. The second that also controls the rotation of
And a magnetic pole surface parallel to the second plane at a position symmetrical with respect to a second plane including the two guide shafts, and the first and second bearings. A pair of permanent magnets disposed around one of the bearing portions, and a pair of permanent magnets integrally formed with the permanent magnet and disposed so as to face one magnetic pole surface of the permanent magnet with a predetermined gap therebetween. A yoke member, a drive coil disposed in a gap between the yoke member and the permanent magnet, and generating a thrust in the axial direction of the two guide shafts between the yoke member and the permanent magnet by energization; An attraction member made of a magnetic material integrally formed with a coil and disposed close to one of the pair of permanent magnets; one of the permanent magnet or the drive coil; and the lens The first and second bearing portions are integrally formed. Therefore, the lens driving mechanism, characterized by comprising a slidably supported by the lens moving frame in the axial direction of the two guide shafts.