JPH0954967A - Optical pickup device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To independently respectively set desired resonance frequencies in a focusing and in a tracking by forming inner yokes to specific shapes. SOLUTION: A lens holder 24 is supported by a supporting shaft 25 to enable the focusing and the tracking movements of an objective 22. Driving magnets 30, 32 for focusing and tracking form magnetic fluxes acting on driving coils 26, 28 for focusing and tracking by being respectively opposed to inner yokes 34a, 34b. The magnetic flux densities from the driving magnets 30 are maximum in the center parts of the magnets and generate the restoring force to a neutral position by attracting magnetic pieces 39 fixed to the lens holder 24. Adjustment protrusion parts 34c having shapes long and thin in a focusing direction are formed on the surfaces of the inner yokes 34a opposed to the driving magnets 30 and then desired resonance frequencies are obtained by changing the magnitudes and distribution shapes of the magnetic fluxes while adjusting heights of the protrusion parts.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical pickup device incorporated in an optical disc device or the like. More specifically, the present invention relates to a driving device for a lens holder that holds an objective lens of an optical pickup device.

[0002]

2. Description of the Related Art As an optical pickup device incorporated in an optical disc device for reproducing an optical disc which is a digital recording medium, a conventional optical pickup device is disclosed in, for example, Japanese Patent Laid-Open No. 7-11095.
Some are disclosed in No. 5. As shown in FIG.
In this optical pickup device 1, a lens holder 2 is supported by a support shaft 4 so as to be rotatable and axially slidable. A focusing drive coil 6 and a tracking drive coil 8 are fixed to the outer peripheral surface of the lens holder 2 in pairs at target positions sandwiching the support shaft 4.

Around the lens holder 2, an arc-shaped outer yoke 10 centering on the support shaft 4 is formed. An arcuate drive magnet 12 centered on the support shaft 4 is fixed to the inner surface of the outer yoke 10. Here, a groove portion 12 a parallel to the support shaft 4 is formed in the middle portion of the inner surface of the drive magnet 12. The groove 12a forms a focusing drive magnet portion 12b and a tracking drive magnet portion 12c.

Further, inside the yoke hole 2a of the lens holder 2, an arc-shaped inner yoke 14 centered on the support shaft 4 is provided.
Is arranged. The inner yoke 14 faces the drive magnet 12. Furthermore, the lens holder 2
A magnetic piece 16 is fixed to a position facing the central portion of the focusing drive magnet portion 12b on the outer peripheral surface of the magnetic piece 16.

On the other hand, between the focusing drive magnet portion 12b and the inner yoke 14, as shown in FIG.
A distribution of the magnetic flux density is formed so that the central portion of the focusing drive magnet portion 12b is maximized. For this reason,
When the drive coils 6 and 8 are not energized, the magnetic piece 16 is attracted to the center of the focusing drive magnet portion 12b. This state is the neutral state. When the drive coils 6 and 8 are energized in the neutral state, the lens holder 2 is rotated around the support shaft 4 to perform a tracking operation, or the lens holder 2 is slid along the support shaft 4 to perform a focusing operation. Is done. In any case, when the energization is stopped, the magnetic piece 16 is attracted to the central portion of the focusing drive magnet portion 12b to be in a neutral state.

By the way, as shown in FIG. 9, the relationship between the frequency of the input current and the gain when the lens holder 2 is rotated depends on the resonance frequency of the lens holder 2. Here, at frequencies above the resonance frequency, the gain decreases in proportion to the input frequency. At a frequency that does not exceed the resonance frequency, the gain is almost constant regardless of the input frequency. At this time, the higher the resonance frequency, the smaller the gain,
The lower the resonance frequency, the larger the gain. Therefore, the relationship between the input frequency and the gain at frequencies lower than the resonance frequency is
It is determined by the resonance frequency of the lens holder 2.

On the other hand, the finished product of the optical pickup device 1 is required to have the sensitivity of the tracking operation and the focusing operation with respect to the input current of the lens holder 2 within a predetermined range. Therefore, the resonance frequency of the lens holder 2 must be set in advance in order to set the sensitivity and the gain to predetermined values. Since the setting of the resonance frequency is related to the magnetic flux density acting on the magnetic piece 16, it is performed by changing the shape, surface area, and volume of the magnetic piece 16.

[0008]

However, in the optical pickup device 1 described above, the resonance frequency of the lens holder 2 is set by changing the shape, surface area, and volume of the magnetic piece 16, so that the desired resonance frequency is obtained. In order to obtain the above, it was necessary to repeat trial and error of changing the shape, surface area and volume of the magnetic piece 16. That is, it is unknown how to determine the shape and the like of the magnetic piece 16 in order to set the resonance frequency to a predetermined value. The one that matches the value was adopted. For this reason, the work of setting the resonance frequency is extremely complicated and requires a lot of time and labor.

Further, when it is necessary to change the resonance frequency during the focusing operation, if the shape of the magnetic piece 16 is changed, the resonance frequency during the tracking operation is also changed. On the contrary, when the resonance frequency during the tracking operation is changed and the shape of the magnetic piece 16 is changed, the resonance frequency during the focusing operation is also changed. Therefore, the work of setting the resonance frequency becomes more complicated.

Therefore, a first object of the present invention is to provide an optical pickup device capable of easily performing the setting work of the resonance frequency of the lens holder. Also,
A second object of the present invention is to provide an optical pickup device capable of separately and independently setting the resonance frequencies of the focusing operation and the tracking operation.

[0011]

In order to achieve the above object, an optical pickup device according to a first aspect of the present invention holds an objective lens, and a lens holder movable in a tracking direction and a focusing direction and fixed to the lens holder. A drive coil, a drive magnet that faces the drive coil, an inner yoke that faces the opposite side of the drive magnet with the drive coil in between, and a magnet that is attached to the lens holder and is attracted to the drive magnet by magnetic force. In the optical pickup device including the one piece, an adjusting protrusion protruding toward the driving magnet is formed at a portion on the facing surface of the inner yoke facing at least the central portion of the driving magnet.

Therefore, the magnetic flux density between the drive magnet and the inner yoke becomes maximum in the central portion of the drive magnet and becomes smaller as it approaches the end portion of the drive magnet.
Then, by changing the height of the adjusting protrusion of the inner yoke, the distance between the drive magnet and the inner yoke is changed, so that the distribution of the magnetic flux density is changed.

Therefore, when the adjusting protrusion is raised, the distance between the central portion of the drive magnet and the inner yoke is shortened.
As a result, the maximum value of the magnetic flux density increases and the overall shape of the magnetic flux density distribution also changes. On the other hand, when the adjusting protrusion is lowered, the space between the central portion of the drive magnet and the inner yoke is expanded. As a result, the maximum value of the magnetic flux density becomes small, and the overall shape of the magnetic flux density distribution also changes. Here, if the relationship between the height of the adjusting protrusion and the maximum value of the magnetic flux density of the driving magnet is obtained in advance by experiments, etc., the height of the adjusting protrusion for obtaining the predetermined value of the magnetic flux density can be easily calculated. can do.

Therefore, when a predetermined sensitivity is required for the lens holder of the finished optical pickup device, the gain for achieving this sensitivity is obtained, and the resonance of the lens holder is obtained from the Bode diagram as shown in FIG. Calculate the frequency. Then, the height of the adjusting protrusion is determined so that the magnetic flux density is the resonance frequency, and the inner yoke is molded. By using this inner yoke, it is possible to secure the predetermined sensitivity required for the lens holder.

According to the optical pickup device of claim 2,
The adjusting protrusion is formed in a shape whose longitudinal direction is the focusing direction.

Therefore, when the lens holder rotates in the tracking direction, the magnetic flux density distribution hardly changes depending on the position of the lens holder in the focusing direction. That is, the magnetic flux density acting on the magnetic piece during the tracking operation is not affected by the focusing operation. As a result, the height of the adjusting protrusion can be changed to set the resonance frequency in the tracking operation without being affected by the focusing operation. Moreover, since the resonance frequency in the focusing operation hardly changes even if the height of the adjusting protrusion is changed, only the resonance frequency in the tracking operation can be set independently.

Further, in the optical pickup device of the third aspect, the adjusting protrusion is formed in a shape having the tracking direction as the longitudinal direction.

Therefore, when the lens holder slides in the focusing direction, the magnetic flux density distribution hardly changes depending on the position of the lens holder in the tracking direction. That is, the magnetic flux density acting on the magnetic piece during the focusing operation is not affected by the tracking operation. This makes it possible to change the height of the adjusting protrusion and set the resonance frequency in the focusing operation without being affected by the tracking operation. Moreover, since the resonance frequency in the tracking operation hardly changes even if the height of the adjusting protrusion is changed, only the resonance frequency in the focusing operation can be set independently.

According to the optical pickup device of claim 4,
The adjusting protrusion includes a focusing direction protrusion having a longitudinal direction in the focusing direction and a tracking direction protrusion having a longitudinal direction in the tracking direction.

Therefore, when the lens holder rotates in the tracking direction, the magnetic flux density distribution in the tracking operation hardly depends on the position of the lens holder in the focusing direction. Further, when the lens holder slides in the focusing direction, the magnetic flux density distribution in the focusing operation hardly depends on the position of the lens holder in the tracking direction. This makes it possible to change the height of the protruding portion in the focusing direction and set the resonance frequency in the tracking operation without being affected by the focusing operation. Further, the height of the tracking direction protrusion can be changed to set the resonance frequency in the focusing operation without being affected by the tracking operation.

Moreover, even if the height of the protruding portion in the focusing direction is changed, the resonance frequency in the focusing operation hardly changes, and even if the height of the protruding portion in the tracking direction is changed, the resonance frequency in the tracking operation hardly changes. Therefore, the resonance frequency in the tracking operation and the resonance frequency in the focusing operation can be set independently of each other.

Further, the resonance frequency in the tracking operation and the resonance frequency in the focusing operation can be set at the same time by simultaneously changing the heights of the projections in the focusing direction and the projections in the tracking direction.

Further, in the optical pickup device of the fifth aspect, the drive magnet is arranged in an arc shape along the tracking direction of the lens holder and is arranged on the outer peripheral side of the drive coil, and the inner yoke is formed in a flat plate shape facing the drive coil. And is arranged on the inner peripheral side of the drive coil.

Therefore, the distance between the drive magnet and the inner yoke excluding the adjusting protrusion is large at the center of the drive magnet and short at the end of the drive magnet in the tracking direction. As a result, the magnetic flux density between the drive magnet and the inner yoke becomes maximum at the central portion of the drive magnet and gradually decreases toward the end portion of the drive magnet in the tracking direction. By providing the adjusting protrusion on the inner yoke, the maximum value of the magnetic flux density can be set.

Therefore, even if the magnetic piece moves with respect to the drive magnet when the rotation angle of the lens holder or the sliding amount in the axial direction becomes large, the amount of change in the magnetic flux density acting on the magnetic piece from the drive magnet is small. small. Since the change amount of the magnetic flux density is small, the change amount of the resonance frequency of the lens holder is small. Therefore, the amount of change in gain at a frequency lower than the resonance frequency with respect to the input voltage to the drive coil is small.

According to the optical pickup device of claim 6,
A support shaft that supports the lens holder so as to be rotatable in the tracking direction and slidable in the focusing direction is provided. Therefore, the lens holder is rotated or slid while being supported by the support shaft.

Further, in the optical pickup device of the seventh aspect, the drive coil is a focusing drive coil, and the drive magnet is a focusing drive magnet.

Therefore, the magnetic flux density between the focusing drive magnet and the inner yoke becomes maximum at the central portion of the focusing drive magnet, and gradually decreases as it approaches the end portion of the focusing drive magnet.

[0029]

BEST MODE FOR CARRYING OUT THE INVENTION The structure of the present invention will be described below in detail based on the embodiments shown in the drawings.

As shown in FIGS. 1 to 3, the optical pickup device 20 of the present invention includes a lens holder 24 for holding an objective lens 22 and a support shaft 2 for supporting the lens holder 24.
5, a driving coil for focusing 26 and a driving coil for tracking 28 as driving coils fixed to the outer periphery of the lens holder 24, and focusing as driving magnets arranged outside the respective driving coils 26, 28 to face each other. Driving magnet 30, tracking driving magnet 32, and focusing driving magnet 30
Along with the focusing drive yoke 26, the focusing inner yoke 34a and the tracking drive magnet 32 are used together with the tracking drive coil 2.
An inner tracking yoke 34b positioned with 8 in between,
Adjustment protrusion 3 provided on the inner yoke 34a for focusing
4c and the magnetic piece 38 provided on the outer peripheral portion of the lens holder 24.
And an outer yoke 4 for fixing the drive magnets 30 and 32 to each other.
0a and 0a.

The lens holder 24 is supported by a support shaft 25 so as to be rotatable and axially slidable. In the present embodiment, the lens holder 24 is supported by the support shaft 25, but the structure may be such that the lens holder is supported by, for example, four hinges without using the support shaft. The objective lens 22 is held in the lens holder 24 with its optical axis parallel to the support shaft 25. Also,
A balancer 42 is fixed to the lens holder 24 on the opposite side of the objective lens 22 about the support shaft 25. A focusing drive coil 26 and a tracking drive coil 28, which are paired with each other with the support shaft 25 interposed therebetween, are fixed to the outer peripheral surface of the lens holder 24.

The outer yoke 40a is supported by an outer yoke support plate 40b which is perpendicular to the support shaft 25. The outer yoke 40a and the outer yoke support plate 40b are formed of the same metal plate 40. A through hole is provided in the central portion of the outer yoke support plate 40b to form a boss portion 40c. The support shaft 25 is fixed to the boss portion 40c by press fitting or adhesion. A pair of focusing drive magnets 30 and a pair of tracking drive magnets 32 are fixed to the outer yoke 40a at positions facing each other with the support shaft 25 in between. Further, the focusing drive magnet 30 and the tracking drive magnet 32 are arranged so as to face the focusing drive coil 26 and the tracking drive coil 28, respectively.

Further, a magnetic piece 38 is attached to the outer peripheral surface of the lens holder 24 at a position facing the center of the focusing drive magnet 30. In this embodiment, the magnetic piece 38 is provided at a position facing the central portion of the focusing drive magnet 30, but as shown by the chain double-dashed line in FIG.
It may be provided at a position facing the central portion of the. In any structure, the magnetic piece 38 is attracted to the central portions of the drive magnets 30 and 32 and is in a neutral state.

On the other hand, an inner yoke support plate 34g is superposed on the outer yoke support plate 40b. Inner yoke support plate 34g
A flat plate-shaped focusing inner yoke 34a facing the focusing drive magnet 30 and a flat plate-shaped tracking inner yoke 34b facing the tracking drive magnet 32 are provided at both ends facing each other with the support shaft 25 in between. It is provided. The focusing inner yoke 34a, the tracking inner yoke 34b, and the inner yoke support plate 34g are formed of the same metal plate 34. Here, the distance between each drive magnet 30, 32 and each inner yoke 34a, 34b is determined by
The drive magnets 30 and 32 are large at the center of 0 and 32.
It is supposed to be small at the side edge of.

Further, the inner yoke 34a for focusing is used.
On the surface facing the focusing drive magnet 30, there is formed an adjusting projection 34c including the portion facing the central portion of the focusing drive magnet 30 and having the longitudinal direction parallel to the support shaft 25. Further, a groove 34d is formed at a position corresponding to the back side of the adjusting protrusion 34c of the focusing inner yoke 34a.

In this embodiment, since the magnetic piece 38 is provided so as to face the focusing drive magnet 30, it is hardly affected by the magnetic flux of the tracking drive magnet 32. Therefore, the lens holder 24
From the viewpoint of setting the resonance frequency of, the inner tracking yoke 34b may be formed in an arc shape as in the conventional case, and the distance between the tracking drive magnet 32 and the inner tracking yoke 34b may be constant.

The inner yokes 34a and 34b penetrate the yoke hole 24a formed in the lens holder 24 with a spatial margin. Therefore, the focusing drive magnet 30 and the focusing inner yoke 34a
The focusing drive coil 26 is located between the tracking drive coil 32 and the tracking drive magnet 32, and the tracking drive coil 28 is located between the tracking drive magnet 32 and the tracking inner yoke 34b.

The operation of the optical pickup device 20 described above will be described below.

A magnetic flux is generated by energizing the focusing drive coil 26, and a thrust is generated between the magnetic flux generated by the focusing drive magnet 30 and the magnetic flux. As a result, the lens holder 24 slides in the axial direction of the support shaft 25, and the focusing operation is performed. Further, when the tracking drive coil 28 is energized, a magnetic flux is generated,
Thrust is generated between the magnetic flux generated from the tracking drive magnet 32. As a result, the lens holder 24 rotates about the support shaft 25, and the tracking operation is performed.

Here, the distance between the focusing drive magnet 30 and the focusing inner yoke 34a is large in the central portion of the focusing drive magnet 30.
It is made small at the side end of the focusing drive magnet 30. In addition to this, focusing inner yoke 3
By the adjusting protrusion 34c of 4a, the focusing drive magnet 3 in the central portion of the lens holder 24 in the rotation direction is provided.
The distance from 0 is small. Therefore, the magnetic piece 38
As shown by the solid line in FIG. 4, the magnetic flux density that acts on the magnetic flux density becomes maximum at the central portion of the focusing drive magnet 30, and gradually decreases toward the side end portion thereof.

Therefore, in the neutral state, the magnetic piece 38 is attracted to the focusing driving magnet 30 and is positioned close to the central portion where the magnetic flux density is maximum. When the tracking operation is performed, the magnetic piece 38 is positioned away from the center of the focusing drive magnet 30, but the magnetic flux density acting at that position is the same as the magnetic flux density acting in the neutral state. There is no big difference.
Therefore, the resonance frequency of the lens holder 24, which varies depending on the magnetic flux density acting on the magnetic piece 38, does not change significantly even by the tracking operation. Therefore, since the resonance frequency does not change significantly, the gain at a frequency lower than the resonance frequency does not change significantly and becomes stable. Therefore, the tracking operation of the lens holder 24 can be easily controlled by energization with the input voltage calculated from the gain, and the control time can be shortened.

When the inner yoke 34a for focusing is molded, the height of the adjusting protrusion 34c is changed to change the distance from the driving magnet 30 for focusing. As a result, as shown by the broken line in FIG.
The distribution of the magnetic flux density in the tracking operation is changed. For example, when the adjusting protrusion 34c is made high, the interval between the center portion of the focusing drive magnet 30 and the focusing inner yoke 34a is shortened, so that the maximum value of the magnetic flux density is increased. On the other hand, when the adjusting protrusion 34c is lowered, the interval between the central portion of the focusing drive magnet 30 and the focusing inner yoke 34a is expanded, so that the maximum value of the magnetic flux density is reduced. In either case, not only the maximum value of the magnetic flux density changes but also the shape of the distribution changes.

Even when the lens holder 34 is performing the focusing operation, since the adjusting projection 34c has the longitudinal direction parallel to the support shaft 25, the distribution of the magnetic flux density during the tracking operation hardly changes.

Here, if the relationship between the height of the adjusting protrusion 34c and the maximum value of the magnetic flux density of the focusing drive magnet 30 is previously obtained by an experiment or the like, the adjusting protrusion for obtaining a predetermined value of the magnetic flux density can be obtained. The height of 34c can be easily calculated.

The above embodiment is an example of a preferred embodiment of the present invention, but the present invention is not limited to this, and various modifications can be made without departing from the gist of the present invention. For example, in the present embodiment, the adjusting protrusion 34c of the focusing inner yoke 34a is shaped such that the direction parallel to the support shaft 25 is the longitudinal direction. However, as shown in FIG. 5, the rotation direction of the lens holder 24 is the longitudinal direction. It is also possible to make the shape. According to this structure, the magnetic flux density in the focusing operation can be changed by changing the height of the adjusting protrusion 34c. Further, even when the lens holder 34 is performing the tracking operation, the distribution of the magnetic flux density during the focusing operation hardly changes.

Further, as shown in FIG. 6, the adjusting protrusion 34c of the focusing inner yoke 34a is attached to the support shaft 25.
It can also be formed by a focusing direction protrusion 34e having a longitudinal direction parallel to and a tracking direction protrusion 34f having a rotational direction as a longitudinal direction. According to this structure, both the magnetic flux density in the tracking operation and the magnetic flux density in the focusing operation can be changed at the same time by changing the height of the adjusting protrusion 34c. Further, the magnetic flux density in the tracking operation can be set by changing the height of the focusing direction protrusion 34e, and the magnetic flux density in the focusing operation can be set by changing the height of the tracking direction protrusion 34f.

Further, in this embodiment, the focusing drive magnet 30 and the tracking drive magnet 32 are used as the drive magnets, but the drive magnets 30 and 32 may be the same. According to this structure, it is possible to provide the pair of drive magnets including the focusing portion and the tracking portion, and dispose the focusing drive coil and the tracking drive coil facing each other. Then, the number of parts can be reduced.

[0048]

As is apparent from the above description, in the optical pickup device according to the first aspect, the distribution of the magnetic flux density is changed by changing the height of the adjusting protrusion of the inner yoke, and the magnetic flux density is dealt with. The resonance frequency can be obtained to obtain a predetermined gain and sensitivity. Therefore, in order to set the sensitivity of the lens holder of the optical pickup device to a predetermined size, the inner yoke may be molded based on the calculated value, so that the sensitivity can be easily set without trial and error. You can As a result, the sensitivity setting work is simplified, and the manufacturing time and manufacturing cost can be reduced.

Further, in the optical pickup device of the second aspect, the resonance frequency in the tracking operation can be set independently of the resonance frequency in the focusing operation. Therefore, the sensitivity in the tracking operation of the lens holder of the optical pickup device can be easily set.

Further, in the optical pickup device of the third aspect, the resonance frequency in the focusing operation can be set independently of the resonance frequency in the tracking operation. Therefore, the sensitivity in the focusing operation of the lens holder of the optical pickup device can be easily set.

Further, in the optical pickup device of the fourth aspect, the resonance frequency in the tracking operation and the resonance frequency in the focusing operation can be set independently of each other. Therefore, the sensitivity in the tracking operation and the sensitivity in the focusing operation of the lens holder of the optical pickup device can be easily set simultaneously or separately.

Further, in the optical pickup device of the fifth aspect, since the amount of change in the magnetic flux density acting on the magnetic piece from the drive magnet is small, the amount of change in the resonance frequency of the lens holder is small, which corresponds to the input frequency to the drive coil. The amount of change in gain at frequencies lower than the resonance frequency becomes small. As a result, when the lens holder is driven, the input voltage to the drive coil is calculated based on the sensitivity in order to drive the lens holder to the target position. However, if the change amount of the sensitivity is small, the calculated input voltage is accurate. As a result, the driving can be performed accurately. Therefore, control of the lens holder is facilitated, accurate positioning can be performed with a small number of times of driving, the control time is shortened, and the response speed is improved.

Further, since the drive magnet is formed in an arc shape along the rotation direction of the lens holder and is arranged on the outer peripheral side of the drive coil, the size of the optical pickup device is not increased.

Further, in the optical pickup device of the sixth aspect, since the lens holder is supported by the support shaft, rotation and sliding can be performed smoothly. Therefore, the focusing operation and the tracking operation can be performed accurately and surely. Moreover, the optical pickup device is not increased in size.

Further, in the optical pickup device of the seventh aspect, since the driving coil is the focusing driving coil and the driving magnet is the focusing driving magnet, the magnetic piece is hardly affected by the magnetic flux of the tracking driving magnet. Therefore, the shape of the tracking drive magnet and the shape of the inner yoke facing the tracking drive magnet can be the same as the conventional one, and the manufacturing cost is not increased.

[Brief description of drawings]

FIG. 1 is a plan view showing an embodiment of an optical pickup device of the present invention.

FIG. 2 is a vertical cross-sectional view of the optical pickup device showing a state cut along line II-II in FIG.

FIG. 3 is a perspective view showing an inner yoke for focusing and an adjusting protrusion.

FIG. 4 is a graph showing a distribution of magnetic flux density received by a magnetic piece.

FIG. 5 is a perspective view showing another inner yoke for focusing and an adjusting protrusion.

FIG. 6 is a perspective view showing another focusing inner yoke and an adjustment protrusion.

FIG. 7 is a plan view showing a conventional optical pickup device.

FIG. 8 is a graph showing a distribution of magnetic flux density received by a magnetic piece of a conventional optical pickup device.

FIG. 9 is a Bode diagram showing the relationship between the input frequency to each drive coil and the gain.

[Explanation of symbols]

20 Optical Pickup Device 24 Lens Holder 25 Support Shaft 26 Focusing Drive Coil (Drive Coil) 28 Tracking Drive Coil (Drive Coil) 30 Focusing Drive Magnet (Drive Magnet) 32 Tracking Drive Magnet (Drive Magnet) 34a Inside Focusing Yoke (inner yoke) 34b Tracking inner yoke (inner yoke) 34c Adjusting protrusion 34e Focusing direction protrusion 34f Tracking direction protrusion 38 Magnetic piece

Claims (7)

[Claims] 1. A lens holder which holds an objective lens and is movable in a tracking direction and a focusing direction,
A drive coil fixed to the lens holder, a drive magnet arranged to face the drive coil, an inner yoke arranged to face the opposite side of the drive magnet with the drive coil interposed therebetween, and the lens holder to the lens holder. In an optical pickup device provided with a magnetic piece attracted to the drive magnet by magnetic force, in a portion on the facing surface of the inner yoke facing at least the central portion of the drive magnet,
An optical pickup device, characterized in that an adjusting protrusion portion protruding toward the driving magnet is formed. 2. The optical pickup device according to claim 1, wherein the adjusting protrusion is formed in a shape having a longitudinal direction in the focusing direction. 3. The optical pickup device according to claim 1, wherein the adjusting protrusion is formed in a shape having the tracking direction as a longitudinal direction. 4. The adjusting protrusion comprises a focusing direction protrusion having a longitudinal direction in the focusing direction and a tracking direction protrusion having a longitudinal direction in the tracking direction. The optical pickup device according to claim 1. 5. The drive magnet is formed in an arc shape along the tracking direction of the lens holder and arranged on the outer peripheral side of the drive coil, and the inner yoke is formed in a flat plate shape facing the drive coil. The optical pickup device according to any one of claims 1 to 4, wherein the optical pickup device is arranged on the inner peripheral side of the. 6. The support shaft according to claim 1, further comprising a support shaft that supports the lens holder so as to be rotatable in a tracking direction and slidable in a focusing direction. Optical pickup device. 7. The optical pickup device according to claim 1, wherein the drive coil is a focusing drive coil, and the drive magnet is a focusing drive magnet.