JP4294843B2 - Magneto-optical disk unit - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a magneto-optical disk apparatus that performs recording / reproduction with respect to a magneto-optical disk.
[0002]
[Prior art]
In the case where data is recorded on an optical disk by laser beam irradiation, it is effective to reduce the diameter of the beam spot in order to improve the recording density of the optical disk. On the other hand, the magnetic field modulation method is advantageous in improving the linear recording density of the magneto-optical disk and direct overwriting. In the magnetic field modulation method, data recording is performed by irradiating a desired region of the recording layer of the magneto-optical disk with a laser beam to increase the temperature of the region, and appropriately reversing the magnetization direction of the region according to the data to be recorded. Is done. When data is recorded on the magneto-optical disk by the magnetic field modulation method, for example, in the MSR (magnetic super-resolution) reproduction method, the magneto-optical disk is irradiated with a laser beam, and the magnetization direction of the recording layer (record mark) Is transferred to the reproducing layer, and data is read from the polarization direction of the reflected light in accordance with the magnetic direction of the reproducing layer. Therefore, in a magneto-optical disk apparatus configured to record data using a magnetic field modulation method and to reproduce data using light, the recording density of the magneto-optical disk is improved and reading is performed. To increase the accuracy, it is effective to reduce the beam spot diameter.
[0003]
As a magneto-optical disk device configured for the purpose of reducing the diameter of the beam spot, there is one having an optical unit 7 and a magnetic unit 8 as shown in FIG. In the magneto-optical disk apparatus 6 shown in the figure, two objective lens systems 70 are arranged so that the numerical aperture (NA) of the objective lens system 70 of the optical unit 7 as a whole becomes large, for example, 0.8 or more. It is constituted by lenses 70a and 70b. More specifically, one lens 70a is mounted on the slider 71, and the other lens 70b is mounted on the actuator 72 and supported by the carriage 73, and these lenses 70a and 70b are arranged on the same optical axis. Is.
[0004]
When the NA of the objective lens system 70 is increased, the optical aberration caused by the tilt or thickness unevenness of the magneto-optical disk D becomes large. Therefore, in order to compensate for this optical aberration, at least the other lens 70b is arranged in the optical axis direction. Focusing control and the like are performed. Such movement of the lens 70b is performed by moving the actuator 72 using a magnetic field generated by the magnetic circuit MC.
[0005]
On the other hand, the magnetic unit 8 has a magnetic head 80, and this magnetic head 80 is arranged to face the slider 71 with the magneto-optical disk D interposed therebetween. In general, the magnetic head 80 is required to have a magnetic field generation capability of several hundred Oe (Oersted) and high-speed modulation of several tens of MHz, and high-speed and high-density with the magnetic head 80 as close as possible to the magneto-optical disk. In order to enable data recording, the magnetic head 80 is mainly configured as a flying slider. The magnetic head 80 is configured such that a coil 84 that covers the center core portion 83 is disposed in a region surrounded by the side core portion 81 and the back core portion 82. In the magnetic head 80, the center core portion 83 and the like are formed of a soft magnetic material such as MnZn ferrite. Then, when the coil 84 is energized, the magnetic flux is released from the center core portion 83.
[0006]
[Problems to be solved by the invention]
However, the magneto-optical disk device 6 having the above configuration is configured such that the other lens 70b is moved at least in the optical axis direction by the magnetic circuit MC. In many cases, neodymium-based magnets having excellent maximum energy product (BHmax) characteristics are used for the magnetic circuit MC. In this case, there may occur a case in which the magnetic flux leaks to the outside of the magnetic circuit MC due to saturation of the magnetic yoke, and the leakage magnetic flux concentrates on the center core portion 83 of the magnetic head 80. As a result, the magnetic field generated by the magnetic head 80 is affected by the leakage flux of the magnetic circuit MC. When the direction of the current flowing through the coil 84 is repeatedly reversed according to the data to be recorded, the change in magnetic flux changes with time centering on zero as shown in FIG. However, if the magnetic head 80 is affected by the leakage magnetic flux from the magnetic circuit MC, as shown in FIG. That is, since the center of the amplitude of the magnetic flux change is offset from zero, a phenomenon that data cannot be properly recorded on the magneto-optical disk D may occur.
[0007]
Also, when performing MSR reproduction, the leakage magnetic flux from the magnetic circuit MC affects the magnetic head 80, resulting in a transfer failure of the recording mark from the recording layer to the reproduction layer, which may impair the reproduction characteristics. obtain.
[0008]
The present invention has been conceived under the above circumstances, and a lens for recording data on a magneto-optical disk by a magnetic head and focusing the light on the magneto-optical disk can be moved by a magnetic circuit. Another object of the present invention is to suppress the influence of the magnetic flux generated by the magnetic circuit on the magnetic head and the magneto-optical disk.
[0009]
DISCLOSURE OF THE INVENTION
  In order to solve the above problems, the present invention takes the following technical means. That is, the present inventionFirst side ofIn the magneto-optical disk device provided by the above-described optical disk device, at least one lens that is displaceable by a magnetic circuit and disposed on the first surface side of the magneto-optical disk, and the first surface of the magneto-optical disk are: A magneto-optical disk device comprising a magnetic head disposed on the opposite second surface side, wherein a magnetic shield means is provided so as to be positioned between the magnetic circuit and the magneto-optical disk. HaveIn addition, an additional lens mounted on a slider and disposed on the same optical axis as that of the first lens is provided between the first lens and the magneto-optical disk. And the magnetic circuit is mounted on a movable body movable along the first surface, and the magnetic shield means is an opposing surface of the slider facing the magneto-optical disk or a non-opposing surface opposite thereto. And a through hole that allows light to enter from the first lens to the additional lens and is disposed on the non-facing surface so as to surround the additional lens. In addition to being a soft magnetic member, the through hole defines the diameter of the light beam incident on the additional lens.It is characterized by that.
[0010]
In this magneto-optical disk apparatus, even if the magnetic flux generated in the magnetic circuit is directed toward the magnetic head, the magnetic shield means prevents the magnetic flux from reaching the magnetic head or the magneto-optical disk. That is, the magnetic head can apply a magnetic field to the magneto-optical disk without being affected by the magnetic field generated by the magnetic circuit. As a result, even if the direction of the magnetic flux is changed with time according to the data to be recorded by the magnetic head, the amplitude of the magnetic flux change becomes symmetric with respect to zero. As a result, data can be properly recorded on the magneto-optical disk without being affected by the magnetic circuit. In addition, since the magnetic flux leakage does not affect the magneto-optical disk, when reproducing a disk using magnetic super-resolution technology, transfer the recording mark from the recording layer to the reproduction layer properly. Therefore, the reproduction characteristics are not impaired by the magnetic circuit.
[0012]
  In this magneto-optical disk apparatus, an additional lens is provided and an objective lens system is configured by a plurality of lenses, and the numerical aperture of the objective lens system is increased. Even when the objective lens system is composed of a plurality of lenses, the position of one lens is usually displaced by a magnetic circuit in order to manage the focal point formed on the magneto-optical disk. Therefore, it is useful to provide the magnetic shield means even in the magneto-optical disk apparatus having such a configuration.Furthermore, since the soft magnetic member functions also as an aperture, the configuration of the optical system can be simplified.
[0013]
Preferably, the magnetic shield means is arranged so as to spread in parallel with the first surface. In this way, the magnetic shield means can reliably receive the magnetic flux from the magnetic circuit, and a higher magnetic shield effect can be exhibited. As a result, the influence of the magnetic flux from the magnetic circuit on the magnetic head and the magneto-optical disk is avoided as much as possible, and it is possible to more reliably avoid the loss of recording characteristics and reproducing characteristics due to leakage magnetic flux from the magnetic circuit.
[0016]
The magnetic shield means may be provided by forming the entire slider from a soft magnetic material. Then, it is not necessary to separately form a soft magnetic member and attach it to the slider, or to apply a plating or the like on the slider, and to provide the magnetic shielding means simultaneously with the formation of the slider. Therefore, the magnetic shield means can be easily manufactured.
[0017]
It is preferable that at least a part of the peripheral portion of the magnetic shield means be a magnetic path forming portion that rises toward one lens side with respect to the first surface of the magneto-optical disk. If it does in this way, magnetic flux can be emitted towards a magnetic circuit from a magnetic path formation part, and it can return to a magnetic circuit reliably. As a result, the magnetic flux of the magnetic circuit and the magnetic head can be reliably separated, and the magnetic flux from the magnetic circuit can be more reliably avoided from affecting the magnetic head and the magneto-optical disk.
[0018]
The soft magnetic material constituting the magnetic shield means is a magnetic head against the magnetic field strength (generally 10 to 100 Oe) received from the magnetic circuit when there is no magnetic shield means in the vicinity of the recording / reproducing portion of the magneto-optical disk. It is preferable that the magnetic permeability is higher than that of the core portion. On the other hand, when the slider is configured as a floating type, it is desirable that the material has a low specific gravity and a high saturation magnetic flux density in consideration of the dynamic characteristics of the slider. Since it is difficult to satisfy these conditions at a high level, specific material selection is performed according to individual cases. In the present invention, iron or carbon steel is preferably used as the soft magnetic material.
[0019]
  The magneto-optical disk apparatus provided by the second aspect of the present invention comprises at least one lens that is displaceable by a magnetic circuit and disposed on the first surface side of the magneto-optical disk, and the magneto-optical disk A magneto-optical disk apparatus comprising: a magnetic head disposed on a second surface side opposite to the first surface of the optical disk; and positioned between the magnetic circuit and the magneto-optical disk, Magnetic shield means is provided, and an additional lens is provided between the lens 1 and the magneto-optical disk, which is mounted on a slider and arranged on the same optical axis as the lens 1. And the first lens and the magnetic circuit are mounted on a movable body movable along the first surface, and the magnetic shield means includes the magneto-optical disk in the slider. Is provided on at least a part of the facing surface facing the surface or the non-facing surface opposite to the surface, and a through hole is provided to allow light to enter from the first lens to the additional lens. The ferromagnetic member is disposed on the non-facing surface so as to surround the additional lens, and the through hole defines a diameter of a light beam incident on the additional lens.In this configuration, the magnetic flux of the ferromagnetic member prevents the magnetic flux from the magnetic circuit from moving toward the magnetic shield means, and the magnetic flux of the magnetic circuit is prevented from affecting the magnetic head and the magneto-optical disk.
[0020]
Other features and advantages of the present invention will become more apparent from the detailed description given below with reference to the accompanying drawings.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be specifically described with reference to the drawings. 1 to 3 show the main part of the magneto-optical disk apparatus according to the present invention.
[0022]
In a state where the magneto-optical disk D mounted on the spindle Sp is rotated, the magneto-optical disk apparatus 1 records data on the magneto-optical disk D by a magnetic field modulation method, and reproduces the data using light. First surface D of the magneto-optical disk D₁On the side, the carriage 2 is supported by the guide member 20 so as to be movable in the radial direction of the magneto-optical disk D (arrow A direction or B direction in FIG. 1: tracking direction). Such movement of the carriage 2 is performed by a rectilinear drive mechanism 21 such as a rectilinear voice coil motor.
[0023]
The carriage 2 holds an actuator 3 that can be displaced in the thickness direction (focusing direction) of the magneto-optical disk D by the magnetic circuit MC. A first lens 31 is mounted on the actuator 3 such that its lens axis faces the thickness direction of the magneto-optical disk D.
[0024]
The magnetic circuit MC is composed of, for example, a neodymium-based magnet having excellent maximum energy product (BHmax) characteristics, a coil held by the actuator 3, a current-carrying means (not shown), and the like. Reference numerals are given only to the parts to be performed. In the embodiment shown in the figure, the first lens 31 is composed of a single lens. However, the first lens 31 may be configured by combining a plurality of lenses, and the actuator 3 is arranged in two directions, the tracking direction and the focus direction. You may comprise so that a displacement is possible.
[0025]
A reflection mirror 22 such as a galvano mirror is disposed below the actuator 3, and is configured such that light from a laser light source (not shown) is reflected by the reflection mirror 22 and incident on the first lens 31. ing.
[0026]
A slider 4 is supported on the carriage 2 via a suspension member 40. The slider 4 is normally supported so as to be swingable about a predetermined pivot, for example, via a gimbal spring (not shown) with respect to the tip of the suspension member 40.
[0027]
The slider 4 has a base material 41 made of AlTiC (aluminum titanium alloy), calcium titanate, or the like, and the base material 41 has a through hole 41a penetrating in the thickness direction. The second lens 42 is fitted in the through hole 41a. One end of the base material 41 is tapered, and the slider 4 floats by taking an air flow generated by the rotation of the magneto-optical disk D into the facing surface 41b side of the base material 41 facing the magneto-optical disk D. It is configured as follows. Of course, the shape of the slider 4 is not limited to a so-called taper type, and may be, for example, a cylindrical shape.
[0028]
On the non-facing surface 41c opposite to the facing surface 41b of the base material 41, a soft magnetic member 43 as a magnetic shield means is disposed. The soft magnetic member 43 is made of, for example, a soft magnetic material such as iron or carbon steel, and is fixed to the non-facing surface 41c of the base member 41, for example. The soft magnetic member 43 has a magnetic path forming portion 43a that rises toward the actuator 3 at the periphery thereof, and is provided with a through hole 43b so that the second lens 42 is exposed. The peripheral portion of the through hole 43b covers the periphery of the second lens 42 as shown in FIG. 3, and the diameter of the light beam incident on the second lens 42 is defined by the diameter of the through hole 43b. Has been made. That is, the soft magnetic member 43 has a function as an aperture.
[0029]
Note that the thickness of the soft magnetic member 43 is appropriately set so that the magnetic flux from the magnetic circuit MC at the recording / reproducing portion of the magneto-optical disk D is, for example, 30 Oe or less, and when the soft magnetic member 43 is made of iron. Even at about 0.1 mm, a sufficient magnetic shielding effect can be obtained.
[0030]
On the other hand, the first surface D of the magneto-optical disk D₁Second side D opposite to₂On the side, a magnetic head 5 is arranged. In the magnetic head 5, a coil 52 that covers the center core portion 52 is disposed in a region surrounded by the back core portion 50 and the side core portion 51. Each core part 50-52 is formed, for example with soft magnetic materials, such as a MnZn type ferrite. The magnetic head 5 is urged toward the magneto-optical disk D via the suspension member 54 and is configured in a slider shape as a whole. Like the slider 4, the magnetic head 5 floats by the rotation of the magneto-optical disk D. .
[0031]
In the magneto-optical disk apparatus 1 configured as described above, recording and reproduction of data with respect to the magneto-optical disk D are performed as follows. The magneto-optical disk D utilizes a magnetic super-resolution (MSR) technique and has a magnetic film d composed of a recording layer and a reproducing layer.
[0032]
Data recording on the magneto-optical disk D is performed on the second surface D of the magneto-optical disk D with respect to a predetermined area of the recording layer in the magnetic film d of the magneto-optical disk D as shown in FIG.₂This is performed by applying a magnetic field in a predetermined direction from the magnetic head 5 and defining the magnetization direction in the area according to data to be recorded.
[0033]
Such definition of the magnetization direction is determined by the first surface D of the magneto-optical disk D.₁The above-described region of the recording layer is irradiated with light from the side, and the temperature of the region is raised above the Curie temperature of the recording layer. More specifically, light emitted from a light source (not shown) such as a semiconductor laser is converted into parallel light by a collimator lens (not shown), and the light beam reflected by the reflection mirror 22 is reflected by the first lens 31 and the second lens 42. Focusing is performed by forming a laser spot in the region.
[0034]
Data recording is normally performed continuously along the track of the magneto-optical disk D. At this time, since defocusing occurs due to tilt or uneven thickness of the magneto-optical disk D, the defocus is compensated by displacing the position of the first lens 31 together with the actuator 3 by the magnetic circuit MC.
[0035]
Since the magnetic circuit MC has a magnet, the magnetic flux leaks to the outside of the magnetic circuit MC due to the saturation of the magnetic yoke, and this tends to go to the core portions 50 to 52 of the magnetic head 5. On the other hand, in the magneto-optical disk device 1, the soft magnetic member 43 is disposed on the non-facing surface 41c of the slider 4, and this is interposed between the magnetic head 5 and the magnetic circuit MC.
[0036]
For this reason, as clearly shown in FIG. 3, the leakage magnetic flux from the magnetic circuit MC is collected in the soft magnetic member 43 and returns to the magnetic circuit MC again. In particular, if the soft magnetic member 43 has the magnetic path forming portion 43a raised on the magnetic circuit MC side, the magnetic flux can be returned to the magnetic circuit MC more efficiently. Thus, by interposing the soft magnetic member 43 between the magnetic circuit MC and the magnetic head 5 (the magneto-optical desk D), the magnetic flux of the magnetic circuit MC and the magnetic flux of the magnetic head 5 are appropriately separated. . Thereby, the strength of the magnetic field in the recording layer and hence the magnetic film d is hardly affected by the magnetic flux from the magnetic circuit MC. For this reason, if the energization direction of the coil 53 is changed over time according to the data to be recorded, the strength of the magnetic field in the recording layer becomes zero over time as shown in FIG. The amplitude will be the center, and data can be recorded appropriately.
[0037]
On the other hand, data reproduction is performed on the first surface D of the magneto-optical disk D.₁This is performed by irradiating the magnetic film d with light from the side. More specifically, the magnetization direction of the recording layer of the magnetic film d is transferred to the reproducing layer of the magnetic film d, and the recorded data is reproduced from the polarization state of the reflected light from the reproducing layer according to the magnetization direction of the reproducing layer. Is called. As described above, in the magneto-optical disk apparatus 1, the slider 4 is provided with the soft magnetic member 43 so that the magnetic flux from the magnetic circuit MC hardly affects the magneto-optical disk D. For this reason, at the time of transfer of the magnetization direction (record mark) from the recording layer to the reproduction layer at the time of reproduction, the reproduction characteristics are not impaired by the magnetic flux from the magnetic circuit.
[0038]
Here, the light irradiation to the magneto-optical disk D is the same as the light irradiation to the magneto-optical disk D at the time of data recording. Further, the reflected light from the reproducing layer is divided by, for example, a beam splitter (not shown), and then each light is introduced into a photodetector such as a photoelectric conversion element. The reproduction information of the data recorded on the magneto-optical disk D can be obtained from the electrical output from each photodetector. At the same time, for example, a focusing signal is detected by the Foucault method and a tracking signal is detected by the push-pull method. Is done.
[0039]
Using the focusing signal thus obtained, the actuator 3 is displaced in the focus direction, the distance between the first lens 31 and the second lens 42 is optimized, the defocus is adjusted, and the tracking signal is generated. Using this, the actuator 3 is displaced, or the angle of the reflecting surface of the reflecting mirror 22 is adjusted to perform track control.
[0040]
In the magneto-optical disk apparatus 1, the magnetic shield means is provided by fixing the soft magnetic member 43 to the second surface 41c of the slider 4. However, the slider 4 is entirely formed of a soft magnetic material and the slider is formed. 4 may be provided with a magnetic shield function. In addition, the magnetic path forming portion 43 a in the soft magnetic member 43 is not necessarily provided, and it is not necessary to provide the soft magnetic member 43 over the entire area of the second surface 41 c of the slider 4.
[0041]
Next, another example of the magnetic shield means will be described with reference to FIG. In the figure, members or elements equivalent to those of the magneto-optical disk apparatus 1 described above with reference to FIGS. 1 to 3 are denoted by the same reference numerals, and description thereof will be given here. Then, it shall be omitted.
[0042]
The magnetic shield means employed in the magneto-optical disk device 1 ′ shown in FIG. 1 is provided by arranging the ferromagnetic member 43 ′ on the second surface 41 c of the slider 4. The ferromagnetic member 43 ′ is provided with a through hole 43 b ′ so that the second lens 42 is exposed. For this reason, the ferromagnetic member 43 'forms a magnetic field by, for example, polarizing the periphery of the through hole 43b' to the N pole and the peripheral portion to the S pole. This magnetic field prevents leakage magnetic flux from the magnetic circuit MC from moving toward the magnetic head 5 side. As a result, the strength of the magnetic field in the magnetic film (recording layer) at the time of data recording is the same as in the case of the magnetic shield means (see FIGS. 2 and 3) configured as the soft magnetic member 43 described above. Data can be recorded appropriately without being affected by the magnetic flux from the magnetic circuit MC. Of course, even when data is reproduced by MSR reproduction, since the influence from the magnetic circuit MC is hardly received, the reproduction characteristics are not impaired.
[0043]
The magneto-optical disk devices 1 and 1 'shown in the drawings are configured such that the carriage 2 as a moving body moves straight in the radial direction of the magneto-optical disk D. However, the technical idea of the present invention is that The present invention can also be applied to a swing arm type magneto-optical disk apparatus in which the swing arm is movable in a substantially radial direction of the magneto-optical disk.
[0044]
(Supplementary Note 1) At least one lens that is displaceable by a magnetic circuit and disposed on the first surface side of the magneto-optical disk, and a second surface opposite to the first surface of the magneto-optical disk A magneto-optical disk apparatus comprising a magnetic head disposed on the side,
A magneto-optical disk apparatus, wherein a magnetic shield means is provided so as to be positioned between the magnetic circuit and the magneto-optical disk.
(Additional remark 2) Between the said 1 lens and the said magneto-optical disc, the additional lens mounted in the slider and arrange | positioned on the same optical axis as the said 1 lens is provided, and
2. The magneto-optical disk apparatus according to appendix 1, wherein the lens 1 and the magnetic circuit are mounted on a movable body that is movable along the first surface.
(Supplementary note 3) The magneto-optical disk apparatus according to supplementary note 1 or 2, wherein the magnetic shield means is arranged so as to extend in parallel with the first surface.
(Supplementary Note 4) The magneto-optical disk apparatus according to Supplementary Note 2, wherein the magnetic shield means is provided on at least a part of an opposing surface of the slider facing the magneto-optical disk or a non-opposing surface opposite thereto. .
(Supplementary Note 5) The magneto-optical disk apparatus according to Supplementary Note 4, wherein the magnetic shield means is provided by disposing a soft magnetic member made of a soft magnetic material on the non-facing surface.
(Supplementary Note 6) The magnetic shield means is provided with a through hole that allows light to enter from the first lens to the additional lens and is disposed on the non-facing surface so as to surround the additional lens. The magneto-optical disk device according to appendix 5, wherein the magneto-optical disk device is a member and defines the diameter of a light beam incident on the additional lens.
(Additional remark 7) The said magnetic shielding means is a magneto-optical disc apparatus of Additional remark 4 provided by forming the whole said slider with a soft magnetic material.
(Appendix 8) Any one of appendices 3 to 7, wherein at least a part of the peripheral portion of the magnetic shield means is a magnetic path forming portion that rises toward the first lens side with respect to the first surface. 2. A magneto-optical disk device according to 1.
(Supplementary note 9) The magneto-optical disk apparatus according to any one of supplementary notes 5 to 8, wherein the soft magnetic material is iron or carbon steel.
(Supplementary note 10) The magneto-optical disk apparatus according to supplementary note 4, wherein the magnetic shield means is a ferromagnetic member provided on the non-facing surface.
[0045]
【The invention's effect】
As described above, in the optical disk apparatus according to the present invention, the magnetic head applies a magnetic field to a predetermined area of the magnetic film (recording layer) of the magneto-optical disk without being affected by the magnetic flux from the magnetic circuit that displaces the lens. Can be formed. As a result, the direction of the magnetic field can be defined as desired in the area, and data can be recorded appropriately. Even if a magneto-optical disk using magnetic super-resolution technology is used, it is not affected by the magnetic flux from the magnetic circuit, so that the transfer of the recording mark from the recording layer to the reproducing layer can be performed appropriately. The reproduction characteristics are not impaired.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a main part of a magneto-optical disk apparatus according to the present invention.
2 is a cross-sectional view taken along line II-II in FIG.
3 is a cross-sectional view further enlarging the main part of FIG.
FIG. 4 is an enlarged cross-sectional view of a main part of a magneto-optical disk apparatus for explaining another example of magnetic shield means.
FIG. 5 is an enlarged cross-sectional view of a main part of a conventional magneto-optical disk device.
6A and 6B are graphs showing changes over time in the strength of a magnetic field in a magnetic layer, in which FIG. 6A shows an example in which the magnetic layer is not affected by magnetic flux from the magnetic circuit of the optical head, and FIG. An example in the case of receiving the influence of the magnetic flux from is shown.
[Explanation of symbols]
1 Magneto-optical disk unit
2 Carriage (moving body)
31 1st lens (1 lens)
4 Slider (moving body)
41b Opposite surface (of slider)
41c Non-facing surface (slider)
42 Second lens (additional lens)
43 Soft magnetic members (magnetic shield means)
43a Magnetic path forming part (of soft magnetic member)
43b Through hole (of soft magnetic member)
43 'Ferromagnetic member (magnetic shield means)
43b 'through hole (for ferromagnetic member)
5 Magnetic head
MC magnetic circuit
D magneto-optical disk
D₁  First side (of magneto-optical disk)
D₂  Second side (of magneto-optical disk)

Claims (3)

At least one lens that is displaceable by a magnetic circuit and disposed on the first surface side of the magneto-optical disk, and is disposed on the second surface side of the magneto-optical disk opposite to the first surface. A magneto-optical disk device comprising:
Magnetic shield means is provided so as to be positioned between the magnetic circuit and the magneto-optical disk ,
An additional lens mounted on the slider and disposed on the same optical axis as the first lens is provided between the first lens and the magneto-optical disk, and
The 1 lens and the magnetic circuit are mounted on a movable body movable along the first surface,
The magnetic shield means is provided on at least a part of a facing surface facing the magneto-optical disk in the slider or a non-facing surface opposite thereto, and
A through-hole that allows light to enter from the first lens to the additional lens is provided and is a soft magnetic member disposed on the non-facing surface so as to surround the additional lens. A magneto-optical disk apparatus characterized in that a diameter of a light beam incident on an additional lens is defined . 2. The magneto- optical disk apparatus according to claim 1, wherein at least a part of a peripheral portion of the magnetic shield means is a magnetic path forming portion that rises toward the first lens side with respect to the first surface . At least one lens that is displaceable by a magnetic circuit and disposed on the first surface side of the magneto-optical disk, and is disposed on the second surface side of the magneto-optical disk opposite to the first surface. A magneto-optical disk device comprising:
Magnetic shield means is provided so as to be positioned between the magnetic circuit and the magneto-optical disk,
An additional lens mounted on the slider and disposed on the same optical axis as the first lens is provided between the first lens and the magneto-optical disk, and
The 1 lens and the magnetic circuit are mounted on a movable body movable along the first surface,
The magnetic shield means is provided on at least a part of a facing surface facing the magneto-optical disk in the slider or a non-facing surface opposite thereto, and
The first lens is a ferromagnetic member that is provided on the non-facing surface so as to surround the additional lens with a through hole that allows light to enter the additional lens. A magneto-optical disk apparatus characterized in that a diameter of a light beam incident on an additional lens is defined .

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