JP2003067996A - Memory head for magneto-optical - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reproduce the recorded information with high precision. SOLUTION: A memory head for the magneto-optical disk has base members BS and SP facing the recording tracks arranged in the radial direction on the magneto-optical disk 10, and a magnetic reproduction section RA secured to these base members BS, SP to reproduce the information recorded on the recording tracks. Especially, the magnetic reproduction section RA includes an array 30A composed of GMR elements 30 arranged almost in a matrix to detect the information recorded as the changes of the magnetizing directions on the tracks and to convert those changes into electric resistance changes. The reproduction element array 30A has a small inclination in the tangential direction orthogonal to the radial direction of the disk 10 to allocate each GMR element to each track.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention generally relates to a magneto-optical disk memory head for recording / reproducing information on / from a magneto-optical disk, and more particularly to information recorded on a magneto-optical disk at a super high density by a semiconductor laser device. The present invention relates to a memory head for a magneto-optical disk for reproducing data.

[0002]

2. Description of the Related Art In recent years, various types of memory heads using a magneto-optical disk as a recording medium have been developed. A typical memory head is configured so that laser light oscillated from a single semiconductor laser device is converged by, for example, a lens and irradiated onto a recording medium as a spot beam, and the physical change of the recording medium due to the irradiation of this laser light. To record the information as. With this configuration, even if a lens with a large numerical aperture is used, the beam diameter can be narrowed to only a fraction of the wavelength due to the diffraction phenomenon of laser light. Therefore, even if the wavelength 41
Even if 0 nm violet laser light is used, the recording capacity of a recording medium having a diameter of 120 mm is limited to about 10 to 30 gigabytes.

Recently, a contact-type memory head, which comes into contact with a recording medium covered with a lubricating protective film, can be drastically increased in recording density of the recording medium by application of near-field optics. This memory head uses vertical cavity surface emission (VCSEL).
ace Emitting Laser) A semiconductor laser device is used as a light source, and the laser light is totally reflected and confined by the inner surface of a cone-shaped total reflection prism that is integrated with this semiconductor laser device to promote the generation of a strong standing wave. An evanescent wave of laser light is directed toward the recording medium from the tip of the reflecting prism. With this configuration, the beam diameter of the laser light can be set to about 1/20 to 1/100 of the wavelength. When the wavelength of the laser light is, for example, 830 nm, an evanescent wave having a diameter of 40 nm to 10 nm can be obtained on the recording medium under appropriate conditions.
If recording tracks having a width of 10 to 20 nm are arranged without a gap so as to correspond to a beam spot having a diameter of 10 nm, a recording medium having a diameter of 120 mm can have a recording capacity of 1 to 2 terabytes.

By the way, the contact type memory head described above can be used for reproducing information recorded on a recording medium as a physical change by adding a reproducing component. The information recorded on the magneto-optical disk is
For example, a laser beam is emitted from a VCSEL semiconductor laser element to a magneto-optical disk, and a change in laser oscillation based on reflected light reflected by the magneto-optical disk and incident on the tip of a total reflection prism is reflected by a non-output side mirror of the VCSEL semiconductor laser element. It is reproduced by detecting with a photodiode which is arranged behind in consideration of the phase change of light.

[0005]

However, in a recording medium such as a magneto-optical disk, it is necessary to reproduce recorded information based on a very small amount of reflected light, and it is necessary to achieve a required reproduction accuracy. It is difficult to obtain a sufficient signal noise ratio.

An object of the present invention is to provide a magneto-optical disk memory head capable of reproducing recorded information with higher accuracy.

[0007]

According to the present invention, a base member facing a plurality of recording tracks arranged in a radial direction of a magneto-optical disk and a base member for reproducing information recorded on these recording tracks are provided. A fixed magnetic reproducing unit is provided, and the magnetic reproducing unit is a reproducing unit in which a plurality of magnetoresistive elements that detect changes in the magnetization direction recorded as information on a plurality of recording tracks as changes in electrical resistance are arranged in a substantially matrix form. The reproducing element array includes an element array, and the reproducing element array has a small angle inclination with respect to the tangential direction perpendicular to the radial direction of the magneto-optical disk in order to allocate these magnetoresistive elements to different recording tracks. Will be provided.

In this memory head, instead of indirectly detecting the physical change of the magneto-optical disk corresponding to the recorded information from the slight amount of reflected light from the magneto-optical disk, the physical change is detected by the magnetoresistive element. A change in a certain magnetization direction is directly detected as a change in electric resistance. In addition, since the magnetoresistive element has high sensitivity, the detection operation can be performed with an extremely high signal noise ratio as compared with the case where the reflected light is used. Therefore, the reproduction accuracy of the recorded information can be sufficiently improved.

Further, the reproducing element array has a slight angle inclination with respect to the tangential direction perpendicular to the radial direction of the magneto-optical disk in order to allocate a plurality of magnetoresistive elements to different recording tracks. That is, even if a large number of recording tracks exist between the magnetoresistive elements arranged in the column direction, these recording tracks can be traced by the magnetoresistive elements in the row direction. Further, since it is possible to collectively perform the tracking control of the memory head on these recording tracks, a tracking error does not occur for each recording track. Therefore, the reproduction speed of the recorded information can be dramatically improved without lowering the reproduction accuracy due to such a tracking error.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION A memory head for a magneto-optical disk according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a memory head HD for a magneto-optical disk.
2 shows the cross-sectional structure of FIG. 2, and FIG. 2 shows the planar positional relationship between the magneto-optical disk 10 and the memory head HD. This memory head HD is used for recording and reproducing information on a magneto-optical (MO) disk 10 which rotates in one direction around a central axis O as shown in FIG. The magneto-optical disk 10 includes a disk substrate 11, a magneto-optical recording medium layer 12 formed on the disk substrate 11 in order to obtain a plurality of recording tracks 10T that are concentrically arranged in the radial direction R, and the magneto-optical recording medium layer 12 is formed. A lubrication protective film 13 formed on the
And a predetermined number (for example, M × N) of recording tracks 10T
These recording tracks 1 are embedded in the disk substrate 11 for each
The tracking control magnetic layers 14 are arranged in the radial direction R so as to draw a concentric circle with respect to 0T.

When the M × N recording tracks 10T are set spirally in the magneto-optical recording medium layer 12, the tracking control magnetic layer 14 is also similarly formed in the magneto-optical recording medium layer 12. It is set in a spiral shape along 10T.

The magneto-optical recording medium layer 12 is made of TbFeCo or the like and has a thickness of about 5 to 10 nm. The lubrication protection film 13 is composed of a Si ₃ N ₄ film, a SiO ₂ film, an amorphous carbon film, etc., and a lubrication surface having a thickness of about 1 nm obtained by applying a lubricant such as perfluoropolyether to such a film. Have 15.

The memory head HD is constructed so as to be movable in the radial direction R of the magneto-optical disk 10, and has a supporting base BS facing the plurality of recording tracks 10T and two fixed bases BS. The cylindrical leading pad LP and the three-point support spacer SP composed of one cylindrical trailing pad TP are provided as base members. The upper surface of this support base BS is fixed to a gimbal GB integrally provided at the tip of the suspension SP, and the three-point support spacer SP is kept in contact with the lubrication protective film 13 of the magneto-optical disk 10 so that the suspension SP is maintained. It can be pressed down lightly using its elasticity.
Further, a meniscus is generated around the pads LP and TP by the surface tension of the lubricant forming the lubricated surface 15 of the lubrication protective film 13, and the jump amount of the memory head HD accompanying the rotation of the magneto-optical disk 10 is reduced.

The memory head HD further includes an optical recording section WA fixed to the bottom surface of the support base BS for recording information on the plurality of recording tracks 10T, and these recording tracks 1
A magnetic reproducing unit RA fixed to the bottom surface of the support base BS in parallel with the optical recording unit WA in order to reproduce the information recorded at 0T. By the way, since the optical recording unit WA heats up during operation due to a reactive current in the laser injection current and becomes high in temperature, the support base BS cooperates with the gimbal GB and the suspension SP to serve as a heat sink for the optical recording unit WA. Function.

The optical recording unit WA includes a recording element array 20A in which M × N VCSEL semiconductor laser elements 20 are arranged in a matrix and maintains a state in which a predetermined external magnetic field is applied to the magneto-optical disk 10. These VCSELs
The evanescent wave of laser light generated corresponding to information by the oscillation of the semiconductor laser device 20 is generated by the magneto-optical disk 1.
Irradiate vertically toward 0. On the other hand, the magnetic reproducing unit RA has at least M × N spin valve giant magnetoresistive (GM
R: Giant Magneto Resistance) element 30 includes a reproducing element array 30A in which the recording element array 30A is arranged in the same manner as the recording element array 20A.
A change in the magnetization direction recorded as information in T is detected as a change in electric resistance. The evanescent wave forms a rectangular beam spot with a width of about 10 nm (or a circular beam spot with a diameter of about 10 nm) on the magneto-optical recording medium layer 12 of the magneto-optical disk 10, and the recording track 10T is magnetized in the magnetization direction corresponding to the information. So that the magneto-optical recording medium layer 12 is heated. In this case, the plurality of recording tracks 10T are arranged in the radial direction R without a gap with a width of, for example, 20 nm determined based on the beam size. Incidentally, the recording element array 20A and the reproducing element array 30A are the same as those shown in FIG.
The point support spacer SP is maintained substantially horizontally with respect to the magneto-optical recording medium layer 12 while being in contact with the magneto-optical disk 10.

As shown in FIG. 2, the recording element array 20A
Is fixed to the support base BS as an optical recording unit WA, and M ×
In order to allocate N VCSEL semiconductor laser devices 20 to different recording tracks 10T, the magneto-optical disk 1
It has a small angle θ with respect to a tangential direction (tangential direction) K that is perpendicular to the radial direction R of 0. The reproducing element array 30A is fixed to the support base BS as a magnetic reproducing portion RA, and in order to allocate at least M × N GMR elements 30 to different recording tracks 10T, the reproducing element array 30A is arranged in the radial direction of the magneto-optical disk 10 like the recording element array 20A. It has an inclination of a small angle θ with respect to the tangential direction K perpendicular to R. 1 and 2, the structures of the optical recording unit WA and the magnetic reproducing unit RA are shown in a simplified manner than they actually are. More specifically, the numbers of the VCSEL semiconductor laser device 20 and the GMR device 30 are M = 100 and N = 1.
It is 00.

FIG. 3 shows a VCSEL semiconductor laser device 20 and a GMR device 30 for a plurality of recording tracks 10T.
The arrangement of is shown in detail. Here, the VCSEL semiconductor laser device 20 and the GMR device 30 are set to have the same plane size, and the emission point of the evanescent wave is at each V
It is set at the center of the CSEL semiconductor laser device 20, and the detection point of the change in the magnetization direction is set at the center of each GMR device 30.

The VCSEL semiconductor laser device 2 in which the recording device array 20A is arranged in M columns × N rows as shown in FIG.
When the matrix is 0, each column is composed of N VCSEL semiconductor laser devices 20, and each row is composed of M VCSEs.
The L semiconductor laser device 20 is used. VCSE of each row
The L semiconductor laser device 20 is set parallel to the axis L1 inclined by a small angle θ with respect to the radial direction R of the magneto-optical disk 10, and the VCSEL semiconductor laser devices 20 in each row are perpendicular to the radial direction R of the magneto-optical disk 10. It is set parallel to the axis L2 inclined by a small angle θ with respect to the tangential direction K. As a result, the M recording tracks 10T face the centers of the M VCSEL semiconductor laser devices 20 in each row, and the M × N recording tracks 10T in the entire recording device array 20A are M × N VCSEL semiconductors. It faces the center of the laser element 20, respectively.

Further, as shown in FIG. 3, the reproducing element array 30A has GMR elements 30 arranged in M columns × (N + 2) rows.
In the matrix, each column is composed of N + 2 GMR elements 30, and each row is composed of M GMR elements 30. The GMR elements 30 in each column are set parallel to the axis L1 inclined by a small angle θ with respect to the radial direction R of the magneto-optical disk 10, and the GMR elements 30 in each row are set in the magneto-optical disk 10.
Is set parallel to the axis L2 that is inclined by a small angle θ with respect to the tangential direction K that is perpendicular to the radial direction R. As a result, M recording tracks 10T have M recording tracks 10T for each row.
The M × N recording tracks 10T in the entire reproducing element array 30A face the centers of the MR elements 30 and the M × N GMR elements 30 respectively. here,
GMR element 30 in the first row and GMR in the (N + 2) th row
The element 30 is left for tracking control.

Further, as can be seen from FIG. 3, each recording track 10T faces both the center of the corresponding VCSEL semiconductor laser device 20 and the center of the corresponding GMR device 30. This is because the information recorded on the recording track 10T immediately after the information is recorded on the recording track 10T by the VCSEL semiconductor laser device 20 as the magneto-optical disk 10 rotates.
This is because reproduction is possible with the MR element 30.

In the structure of the reproducing element array 30A shown in FIG. 3, the number of elements of the GMR element 30 excluding those for tracking control is the semiconductor laser element 2 in order to facilitate understanding of the invention.
The number of elements is set to M × N, which is equal to the number of elements. In practice, in order to compensate for the tracking error caused by the eccentricity when the magneto-optical disk 10 is rotated, it is preferable to set the number of semiconductor laser elements 20 to about twice. That is, since the recording tracks 10T are arranged with an extremely narrow width, it is virtually impossible to mechanically correct the head position so as to eliminate the tracking error due to the eccentricity of the magneto-optical disk 10T.
The redundancy of the MR element 30 is necessary to perform an electrical tracking process that makes the signals output in parallel from the GMR elements 30 effective within a predetermined range shifted based on the tracking error.

FIG. 4 shows the structure of the optical recording unit WA in detail.
The optical recording unit WA includes an external magnetic field generation unit 21 fixed to the bottom surface of the support base BS, and a recording element array 20A fixed to the bottom surface of the external magnetic field generation unit 21. The external magnetic field generation unit 21 is composed of a magnet, a magnetic body, or a coil that generates a predetermined external magnetic field, and the recording element array 20A has M × N VCSEL semiconductors obtained by integrating the substrate unit 22 and the laser transmission unit 25. It is composed of a laser element 20. The substrate portion 22 has a laser active layer 23 and an AlGaAs / G layer for causing laser oscillation to generate laser light.
MxN VCSs with multi-layer reflective mirror 23 of aAs
It is driven via M × N individual electrodes and a single common electrode corresponding to the EL semiconductor laser device 20, respectively.
In the recording element array 20A, M × N VCSEL semiconductor laser elements 20 are arranged in a matrix without gaps. Each VCSEL semiconductor laser device 20 has, for example, 2 μm
It is a square of width. The laser light transmitting unit 25 is composed of M × N total reflection prisms 26 that are cantilevers integrated with the substrate unit 22 corresponding to the arrangement of these VCSEL semiconductor laser devices 20, for example. These total reflection prisms 26 are made of silicon (Si) crystal or gallium arsenide (G).
aAs) A quadrangular pyramid (or cone) formed by using a crystal or the like, with the widest part having a width (or diameter) of 1 μm.
have. The tip of each total reflection prism 26 has a width of 10 nm.
Square window with a diameter of about 10 nm or circular beam with a diameter of about 10 nm 2
7 is placed. The bottom of the total reflection prism 26 may have a prismatic shape (or a cylindrical shape). Further, the crystal material of the total reflection prism 26 has a higher refractive index than the atmosphere in which the total reflection prism 26 is in contact, and may be replaced with another crystal material as long as it is a material capable of totally reflecting the laser wave therein. . Furthermore, the total reflection prism 26 may be formed to have a coaxial optical fiber tube having a diameter of 10 nm, for example, and to have an evanescent wave emitting rod protruding from the tip. In FIG. 3, the total reflection prism 26 is shown as a quadrangular pyramid.

When the laser light is generated by the substrate 22, the reflection is repeated on the prism surface of the total reflection prism 26 and the substrate 22, and the evanescent wave of the laser light is emitted by the beam window 27 (or the coaxial optical fiber tube). And is emitted vertically toward the magneto-optical disk 20 to form a beam spot on the magneto-optical medium layer 12 of the magneto-optical disk 10. The other laser waves are totally reflected by the prism surface of the total reflection prism 26, are confined inside as reflected laser waves so as not to go out, and contribute to the generation of a strong standing wave. The beam spot of the evanescent wave is generated by the external magnetic field generator 21.
An information bit is recorded by reversing the magnetization direction of the recording track 10T of the magneto-optical recording medium layer 12 under a magnetic field from.

FIG. 5 shows the structure of the magnetic reproducing portion RA in detail. The magnetic reproducing portion RA is laminated and laminated so as to form the reproducing element array 30A, and the supporting base B is formed at the end portion.
It is composed of M array substrates AS fixed to the bottom surface of S. Each array substrate AS is a shield plate 31A and 31B.
And (N + 2) spin valve GMR elements 30 held between these shield plates 31A and 31B. On each array substrate AS, (N + 2) spin valve GMR elements 30 are arranged in a line.
1st GMR element 30 and N + 2nd GMR
The element 30 detects the magnetization direction recorded as a tracking control signal in the pair of magnetic layers 14 embedded in the disk substrate 11 of the magneto-optical disk 10 on both sides of the M × N recording tracks 10T as a change in electric resistance. The second to (N + 1) th GMR elements 30 detect a change in the magnetization direction recorded as information bits on M × N recording tracks 10T in the magneto-optical recording medium layer 12 as a change in electrical resistance.

The magnetic reproducing section RA is a reproducing element array 30.
It is composed of (N + 2) number of array substrates AS that are laminated and bonded to form A and are fixed to the bottom surface of the support base BS at the end portions, and each array substrate AS is a shield plate 31.
A and 31B and these shield plates 31A and 31B
There may be provided M spin valve GMR elements 30 held between B.

Each GMR element 30 is formed on an MR (Magneto Resistance) element section 32 for converting a change in the magnetization direction into a change in electric resistance, permanent magnets 33 arranged on both sides of the MR element section 32, and on this permanent magnet. It is composed of sense electrodes 34A and 34B for flowing a sense current through the MR element section 32. The MR element section 32 includes a magnetization free layer 32A, a magnetic separation layer 32B, a magnetization fixed layer 32C, and an antiferromagnetic layer 32.
It has a structure in which D is sequentially stacked between the shield layers 31A and 31B. As a more specific configuration example, the magnetization free layer 32A is made of NiFe having a thickness of 70 angstroms, the magnetic separation layer 32B is made of Cu having a thickness of 25 angstroms, and the magnetization fixed layer 32C is made of Co having a thickness of 60 angstroms. And the antiferromagnetic layer 32D has a thickness of 12
It consists of 0 Å FeMn.

The magnetization direction of the magnetization fixed layer 32C is fixed by the antiferromagnetic layer 32D, and the magnetization direction of the magnetization free layer 32A is changed by the external magnetic field from the recording track 10T. The magnetization direction of the magnetization fixed layer 32C is parallel to the direction of change of the external magnetic field, and the anisotropic magnetization direction of the magnetization free layer 32A is set at right angles to the direction of the external magnetic field which is the sense current direction. The magnetization direction of the magnetization free layer 32A is fixed by the external magnetic field.
The resistance value also changes when the magnetization direction changes to either parallel or substantially antiparallel to the magnetization direction of 2C. The permanent magnet 33 generates a strong unidirectional uniaxial anisotropic magnetic field to control the magnetic domain in which the magnetic free layer 32A has a single domain structure, and mainly causes Barkhausen noise caused by the domain wall motion of the magnetic domain of the magnetic free layer 32A. Suppress.

Here, as described above, the recording element array 20 is used.
VCSEL semiconductor laser device 2 in which A is 100 rows and 100 columns
0, and the reproducing element array 30A has 102 rows and 100
The operation in the case of being composed of the spin valve GMR elements 30 in a row will be described. When a total of 10,000 evanescent wave laser beams are emitted from the semiconductor laser elements 20 in 100 rows and 100 columns toward the magneto-optical disk 10,
In the magneto-optical recording medium layer 12 of the magneto-optical disk 10, a total of 10,000 beam spots are formed on a total of 10,000 recording tracks 10T having a width of about 200 μm, and the magnetization direction is recorded as information bits on these recording tracks 10T. Furthermore, these recording tracks 10T
The information bit recorded in (1) is detected as a change in electrical resistance in the spin valve GMR element 30 of 100 rows and 100 columns excluding the one for tracking control of the spin valve GMR element 30 of 102 rows and 100 columns.

Such an operation is performed by the recording element array 20A.
And the reproducing element array 30A has an inclination of a small angle with respect to the tangential direction K of the magneto-optical disk 10,
It is realized only when it is possible to trace 10,000 traces of 10,000 continuous beam spots that do not overlap each other with a width of about 20 nm on the recording medium layer 12 of the magneto-optical disk 10. Specifically, in the recording element array 20A and the reproducing element array 30A, θ = a with respect to the tangential direction K of the magneto-optical disk 10.
rctan (2/199) = installed at an angle of 0.57582 degrees. In this state, it is possible to simultaneously record and simultaneously reproduce 10000 tracks of information, that is, 10000 bits of information. Therefore, if 10,000 laser beams have a total width of 200 μm and the disk tangential velocity is 10 mm / sec, 10 Gbit / sec data can be obtained by simultaneously tracing 10000 tracks at 1 Mbit / sec. The transfer speed can be obtained. Further, the magneto-optical disk 10 has, for example, a diameter of 12.
If it is 0 mm, the total recording capacity of the magneto-optical disk 10 reaches about 1 to 2 terabytes.

Here, how to obtain a minute angle when the recording element array 20A and the reproducing element array 30A are tilted will be described. For example, assume that the recording element array 20A is composed of N rows and M columns of the VCSEL semiconductor laser elements 20 as shown in FIG. 3, and the dimension (width or diameter) of the beam window 27 of each VCSEL semiconductor laser element 20 is set. D,
If the spacing between the beam windows 27 in the column direction parallel to the axis L1 is E and the spacing between the beam windows 27 in the row direction parallel to the axis L2 is F, the recording element array 20A has MD + (M-1) in the row direction. It has a length of F and a length of ND + (N-1) E in the column direction. Since each beam window 27 is provided at a distance of E + D from each other in the column direction, M × N laser beams emitted from all the beam windows 27 draw a continuous trajectory without overlapping each other. The angle θ formed by the recording element array 20A and the tangential direction K of the magneto-optical disk 10 is θ = arctan
The relationship of {(D + E) / [MD + M-1) F]} is satisfied. Here, θ is strictly an angle formed by the axis L2 and the tangential direction K of the magneto-optical disk 10.

The inclination of the reproducing element array 30A with respect to the tangential direction is determined so as to match the inclination of the recording element array 20A obtained as described above.

In the above embodiment, the recording element array 20A has M × N VCSEL semiconductor laser elements 2.
When the reproducing element array 30A is composed of 0, the reproducing element array 30A is composed of at least M × N spin valve GMR elements 30. That is, the spin valve GMR element 30 of at least 100 rows and 100 columns is provided for the VCSEL semiconductor laser element 20 of 100 rows and 100 columns. However, in consideration of the tracking error described above, the reproducing element array 30
A may be composed of, for example, spin valve GMR elements 30 of 200 rows and 200 columns, independently of the number of VCSEL semiconductor laser elements 20 that form the recording element array 20A. In this case, when the position of the magnetic layer 14 is significantly displaced from the reference position, the memory head HD is moved to the magneto-optical disk 10.
Rough tracking control that mechanically shifts in the radial direction to reduce this misalignment is performed, and in the state in which the misalignment is reduced, a predetermined range is electrically shifted based on this misalignment amount (tracking error). GMR element 3
Fine tracking control is performed to enable parallel output signals from 0.

Although the spin valve GMR element 30 has been described as being sufficiently smaller than the VCSEL semiconductor laser element 20 in the above-described embodiment, it has been described in various ways when miniaturized in an actual manufacturing process. Subject to dimensional constraints. Currently, the MR element part 32 has a size of 25 nm × 1.
A rectangular GMR element 30 of 00 nm has been developed. When the GMR element 30 having such a size is applied to the recording track 10T having a relatively narrow width, each of the M Gs is recorded.
A reproducing element array 30A is formed by stacking (N + 2) array substrates AS having the MR element 30. In addition to the above-described inclination of the reproducing element array 30A, the reproducing element array 30 is formed.
If the GMR element 30 of A (specifically, the MR element section 32) is uniformly set in the orientation shown in FIG. 6, an effective dimension capable of assigning each MR element section 32 to the corresponding recording track 10T can be obtained. it can.

Further, in the above-described embodiment, the spin valve GMR element 30 is used to form the reproducing element array 30A, but a general magnetoresistive element (MR), spin tunnel magnetoresistive element (TMR), ceramic. It may be replaced with a magnetoresistive element (CMR).

As described above, in the memory head HD of this embodiment, instead of indirectly detecting the physical change of the magneto-optical disk 10 corresponding to the recorded information from the slight amount of reflected light from the magneto-optical disk 10. In addition, the GMR element 30 directly detects the change in the magnetization direction, which is the physical change, as the change in the electric resistance. In addition, since the GMR element 30 has an extremely high sensitivity, the detection operation can be performed with an extremely high signal noise ratio as compared with the case where the reflected light is used. Therefore, the reproduction accuracy of the recorded information can be sufficiently improved.

Further, the reproducing element array 30A has a plurality of GMs.
In order to allocate the R elements to the recording tracks 10T different from each other, there is a slight angle θ with respect to the tangential direction K perpendicular to the radial direction R of the magneto-optical disk 10. That is, a GMR in which a large number of recording tracks 10T are arranged in the column direction
These recording tracks 10T even if they exist between elements
Can be traced with GMR elements in the row direction. Further, since it is possible to collectively perform the tracking control of the memory head HD for these recording tracks 10T, no tracking error occurs for each recording track 10T. Therefore, the reproduction speed of the recorded information can be dramatically improved without lowering the reproduction accuracy due to such a tracking error.

Further, a plurality of GMR elements 30 are arranged in a matrix and the recording tracks 10 are different from each other.
By allocating to T, the bit rate per one of these GMR elements 30 can be reduced to 1 / total number of GMR elements when reproducing a predetermined amount of recorded information, so that all recorded information is reproduced by a single GMR element. It is possible to use an amplifier with a very narrow bandwidth for the amplifier needed. Therefore, the signal noise ratio of the finally obtained recorded information can be dramatically improved.

In the above-described embodiment, the optical recording unit W in which the memory head HD is fixed in parallel to the support base BS.
Although A and the magnetic reproducing unit RA are provided, an optical recording unit having the same structure may be added in parallel as a spare unit. That is, in the manufacturing process, V of the optical recording unit WA
This is because when a defect occurs in any of the CSEL semiconductor laser devices 20, recording is performed on the corresponding recording track 10T instead of the defective semiconductor laser device 20.
A spare unit may be provided in the magnetic reproducing unit RA as well. With such a configuration, the memory head H
The yield of D can be dramatically improved.

[0040]

According to the present invention, it is possible to provide a magneto-optical disk memory head capable of reproducing recorded information with higher accuracy.

[Brief description of drawings]

FIG. 1 is a sectional view showing the structure of a magneto-optical disk memory head HD according to an embodiment of the present invention.

FIG. 2 is a plan view showing a positional relationship between the magneto-optical disk shown in FIG. 1 and a memory head.

FIG. 3 shows a VCS for a plurality of recording tracks shown in FIG.
FIG. 3 is a plan view showing the arrangement of EL semiconductor laser devices and GMR devices in detail.

FIG. 4 is a partial cross-sectional view showing in detail the structure of the optical recording section shown in FIG.

5 is a partial perspective view showing the structure of the magnetic reproducing unit shown in FIG. 3 in detail.

FIG. 6 is a plan view showing a modified example of the reproducing element array shown in FIG.

[Explanation of symbols]

HD ... Memory head BS ... Support base SP: 3-point support spacer 10 ... Magneto-optical disk 10T ... recording track 11 ... Disk substrate 12 ... Magneto-optical recording medium layer 13 ... Lubrication protective film 14 ... Magnetic layer for tracking control 20 ... VCSEL semiconductor laser device 20A ... Recording element array 30 ... Spin valve GMR element 30A ... Reproducing element array

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Claims (5)

[Claims] 1. A plurality of recording tracks for recording information as a change in a magnetization direction by irradiation of an evanescent wave of a semiconductor laser and a plurality of magnetic layers for tracking control embedded in a predetermined number of recording tracks are arranged in a radial direction. A memory head for a magneto-optical disk, comprising: a base member facing the magneto-optical disk; and a magnetic reproducing section fixed to the base member for reproducing information recorded on the predetermined number of recording tracks. In the magnetic reproducing section, a plurality of magnetoresistive elements exceeding a predetermined number are arranged in a matrix so as to detect each tracking control magnetic layer and are recorded on the predetermined number of recording tracks corresponding to the tracking control member. A reproducing element array for detecting a change in the magnetization direction as a change in electric resistance, and the reproducing element array includes a plurality of reproducing element arrays. One of the tracking control members is assigned to a part of the plurality of magnetoresistive elements, and the predetermined number of recording tracks corresponding to the tracking control members are assigned to the rest of the plurality of magnetoresistive elements at right angles to the radial direction. Memory head for a magneto-optical disk characterized by having a small angle of inclination with respect to various tangential directions. 2. The memory head for a magneto-optical disk according to claim 1, wherein the reproducing element array is formed by stacking a plurality of substrates each having one row of magnetoresistive elements arranged side by side. 3. A plurality of magnetoresistive elements having a rectangular shape are uniformly set in a direction in which an effective dimension suitable for the width of the recording track can be obtained. A memory head for a magneto-optical disk as described above. 4. An optical recording unit fixed to the base member for irradiating the magneto-optical disk with the evanescent wave to record information on the predetermined number of recording tracks. 1. A magneto-optical disk memory head according to 1. 5. The optical recording section includes a recording element array in which a predetermined number of semiconductor laser elements that generate the evanescent wave are arranged in a substantially matrix for the predetermined number of recording tracks, and the recording element array is the predetermined number. 5. The memory head for a magneto-optical disk according to claim 4, wherein the number of semiconductor laser elements is inclined to a predetermined angle so as to be assigned to each of the predetermined number of recording tracks, and the inclination of the reproducing element array has a minute angle.