JPH10143933A - Recording medium and information recording / reproducing device - Google Patents

Abstract

(57) [Problem] To reproduce a magneto-optical recording medium for high-density recording, it is impossible to reproduce unless the beam diameter of the reproducing laser beam is reduced. In addition, signals recorded on lands, signals recorded on grooves, and signals recorded as wobbles on both side walls of the groove cannot be independently reproduced. SOLUTION: A wobble for read-only data is provided on a wall on both sides of a groove of a magneto-optical recording medium passing through a track composed of a land and a groove. Further, a means for receiving the laser light and generating at least a first diffracted light and a second diffracted light from the received laser light, wherein the grating is formed so as to form a predetermined angle with respect to the polarization plane of the laser light. Formed,
A signal is reproduced using an optical system including a diffracting unit for guiding the first and second diffracted lights to the objective lens.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording medium and an information recording / reproducing apparatus which achieve high-density recording by improving the quality of a medium and a recording technique, and more particularly, to record a signal using a magnetic field. The present invention relates to a magneto-optical recording medium and a recording / reproducing apparatus for the medium.

[0002]

2. Description of the Related Art Magneto-optical recording media have attracted attention as rewritable, large-capacity, and highly reliable recording media, and have begun to be put to practical use as computer memories and the like. However, with the increase in the amount of information and the downsizing of the apparatus, a higher density recording / reproducing technique is required.

[0003] The high-density recording / reproducing technique includes a medium-side technique and an apparatus-side technique. As the former technique, there are techniques for narrowing the pitch of a medium and improving reproduction resolution by using a magnetic multilayer film. Here, the technology for improving the reproduction resolution by using a magnetic multilayer film selectively transfers the state of the recording layer to the reproduction layer by utilizing the fact that the temperature distribution of the laser spot has a Gaussian distribution that is highest near the center. And read out the state of the reproduction layer. Currently, FAD,
There are three types, RAD and CAD. In these technologies, the front or back of the laser spot is used as a mask,
Thereby, the reproduction density can be made smaller than the laser spot diameter. As a result, it is possible to increase the reproduction density. As the latter technique, there are an optical super-resolution technique for obtaining a condensed spot exceeding the diffraction limit of the laser beam, a reduction in the wavelength of the laser beam, and the like. Further, high-density recording can be realized by modulating the applied magnetic field during recording and pulsing the laser beam, and recording with a minimum domain length of 0.15 μm has been confirmed at present.

[0004]

However, in reproducing a magneto-optical recording medium on which high-density recording has been performed by reducing the shortest domain length, it is usually necessary to reduce the beam diameter of the laser beam used for reproduction. Therefore, there is a limit to reducing the beam diameter. When a super-resolution magneto-optical recording medium is used, it is possible to extract and reproduce only a small domain without reducing the beam diameter of a laser beam. However, in this case, there is a problem that a reproduced signal is small.

Therefore, in the method of recording at a high density by reducing the shortest domain length, even if the recording density can be increased, the reproduction technology cannot follow. The present invention
In order to solve such a problem, a recording medium capable of reproducing data from a magneto-optical recording medium on which high-density recording has been performed without reducing the beam diameter of a laser beam used during reproduction, and a recording / reproducing apparatus for the recording medium are provided. Things.

[0006]

According to the present invention, in a recording medium having a track composed of a land and a groove, wobbles on which signals are recorded are provided on both side walls of the groove, and a recordable material is formed on the surface of the track. It is characterized by having done. Further, the invention is characterized in that the recordable material is a magnetic film.

Further, the present invention is characterized in that the magnetic film includes a first magnetic layer for recording a signal, and a second magnetic layer to which a signal is transferred from the first magnetic layer. Further, the invention is characterized in that the second magnetic layer is formed in contact with the first magnetic layer. Further, the invention is characterized in that a non-magnetic film is formed between the first magnetic layer and the second magnetic film.

Further, the present invention is characterized in that the first magnetic layer is made of a perpendicular magnetic film, and the second magnetic layer is made of an in-plane magnetic film. Further, the present invention provides a single-layer magnetic film or a multi-layer magnetic film of Pt, Pd in which the perpendicular magnetization film is made of TbFeCo or at least one element selected from Tb, Dy, and Nd and Fe, Co, and Ni. , A single-layer magnetic film or a multilayer magnetic film comprising at least one element selected from the group consisting of Fe, Co, and Ni, wherein the in-plane magnetization film is GdFeCo or GdF.
e, or GdCo, or TbCo, or H
at least one selected from o, Gd, Tb, and Dy
The magnetic film is characterized by being a magnetic film comprising an element and at least one element selected from Fe, Co and Ni.

Further, the present invention is non-magnetic film is SiN or AlN,, or TiN, or SiO _2, or Al ₂ O ₃ or SiC, or TiC or ZnO,,, or SiAlON, or ITO, or with SnO ₂ There is a feature. Further, the present invention is characterized in that the structures of the perpendicular magnetization film and the in-plane magnetization film are amorphous structures.

Further, the present invention is characterized in that the structure of the perpendicular magnetic film and the in-plane magnetic film is a polycrystalline or single crystal structure. Further, the invention is characterized in that the shape of the wobble is a sine curve. Further, the present invention is characterized in that the shape of the wobble is a triangular waveform. Also,
The present invention is characterized in that the shape of the wobble is a rectangular waveform.

Further, according to the present invention, the wobble amplitude is 5-4.
It is characterized by being in the range of 0 nm. Further, the present invention is characterized in that the signal recorded on the wobble is a reproduction-only signal. Further, the present invention has a track composed of a land and a groove provided with wobbles for recording signals on both side walls, and faces a recording surface of a recording medium having a recordable material formed on the surface of the track. An objective lens, a laser light generating means for generating a laser light, and means for receiving the laser light and generating at least a first diffracted light and a second diffracted light from the received laser light; A grid is formed so as to form a predetermined angle with respect to
Diffraction means for guiding the first diffracted light and the second diffracted light to the objective lens, and detecting the reflected light of the first diffracted light and the second diffracted light from the recording surface as a push-pull signal or a magneto-optical signal And a light detecting means.

Further, the present invention provides a recording medium having a track composed of a land and a groove provided with wobbles on both sides of which a signal is recorded, wherein a recordable material is formed on the surface of the track. An objective lens provided opposite thereto, laser light generating means for generating laser light, receiving the laser light, and converting the first, second, and third diffracted lights from the received laser light. Means for generating, wherein a grid is formed at a predetermined angle to the track,
Diffracting means for guiding the first, second, and third diffracted lights to the objective lens, and a first diffracted light, a second diffracted light, and a third diffracted light from a recording surface. Light detecting means for detecting the reflected light as a push-pull signal or a magneto-optical signal.

According to the present invention, there is provided a track comprising a land and a groove provided with wobbles on both sides of which a signal is recorded, and a recording surface of a recording medium having a recordable material formed on the surface of the track. An objective lens provided opposite to the first semiconductor laser chip, the first semiconductor laser chip generating a first laser light, and the second semiconductor laser chip generating a second laser light; Receiving a first laser beam and a second laser beam; a laser beam generating unit arranged so that a direction in which the second semiconductor laser chip is arranged and a direction of the track form a predetermined angle; A collimator lens that converts the received laser light into parallel light and guides the collimated light to an objective lens, and the reflected light of the first laser light and the second laser light from the recording surface as a push-pull signal or a magneto-optical signal. Characterized in that it comprises a light-detecting means for output.

According to the present invention, there is further provided a track comprising a land and a groove provided with wobbles on which signals are recorded on both side walls, and a recording surface of a recording medium having a recordable material formed on the surface of the track. An objective lens provided opposite to the first semiconductor laser chip for generating the first laser light, a second semiconductor laser chip for generating the second laser light, and a second semiconductor laser chip for generating the third laser light. And a direction in which the first semiconductor laser chip, the second semiconductor laser, and the third semiconductor laser chip are arranged and a direction of the track are arranged at a predetermined angle. Laser light generating means and light detecting means for detecting reflected light of the first laser light, the second laser light, and the third laser light from the recording surface as a push-pull signal or a magneto-optical signal. And wherein the Mukoto.

The present invention also provides a sample and hold circuit for holding the signal strength of a signal reproduced from a wobble, a signal strength held by the sample and hold circuit as an AGC signal, and a magneto-optical signal based on the AGC signal. And an AGC circuit that amplifies the signal.

[0016]

An embodiment of the present invention will be described with reference to the drawings. Referring to FIG. 1, a magneto-optical recording medium 10 of the present invention is a magneto-optical recording medium in which tracks T are formed spirally. Further, the shape of the track T is not limited to a spiral shape, but may be a concentric shape.
Referring to FIG. 2, the track T includes a land L and a groove G, and wobbles 3 are formed on both sides of the groove. The lands L, the grooves G, and the wobbles 3 are formed when the light-transmitting substrate 1 such as polycarbonate is formed. After the formation of the substrate, a recordable material 2 is formed so as to cover the lands L and the surfaces of the grooves G. In the present embodiment,
A case where a magnetic film is used as the recordable material 2 will be described. In the present invention, not only the address but also the data dedicated to reproduction is recorded in the form of a wobble on both side walls of the groove G, and the recording of rewritable data on the land L or the groove G is one of the methods. Features. That is, the magneto-optical recording medium 10 is a recording medium having a read-only area and a rewritable area.

The details of the magnetic film 2 will be described with reference to FIG. The magnetic film 2 includes an underlayer 21 and a reproducing layer 2.
2, recording layer 24, protective layer 25, and ultraviolet curable resin 2
6 are sequentially formed on the translucent substrate 1. The underlayer 21 is made of SiN, the reproducing layer 2
Reference numeral 2 denotes an in-plane magnetized film, which includes GdFeCo, GdFe, and Gd
A magnetic film made of at least one element selected from Co, TbCo, Ho, Gd, Tb, and Dy and at least one element selected from Fe, Co, and Ni is suitable for the reproducing layer 22. The recording layer 24 is a perpendicular magnetic film, and is a single-layer magnetic film composed of at least one element selected from TbFeCo, Tb, Dy, and Nd and at least one element selected from Fe, Co, and Ni. Or a multilayer magnetic film, at least one element of Pt and Pd and F
e, a single-layer magnetic film or a multi-layer magnetic film comprising at least one element selected from Co, Ni and the recording layer 24.
Suitable for. As the protective layer 25, SiN is suitable. The reproducing layer 22 is not limited to the in-plane magnetization film, but may be a perpendicular magnetization film.

The underlayer 21, the reproducing layer 22,
The recording layer 24 and the protective layer 25 are formed by a magnetron sputtering method. The thickness of each layer is 600 to 800 ° for the underlayer 21 and 50 to 1000 ° for the reproducing layer 22.
Å, the recording layer 24 has a thickness of 500〜3000Å, and the protective layer 25 has a thickness of 500〜1000Å. The thickness of the ultraviolet curable resin is about 10 μm.

Further, the film structure of the magnetic film used for the reproducing layer 22 and the recording layer 24 may be amorphous, polycrystalline or single crystal, but is preferably amorphous. The magnetic film 2 is not limited to the one shown in FIG. 3, but may have a structure in which a nonmagnetic layer 23 is inserted between the reproducing layer 22 and the recording layer 24. The non-magnetic layer 23
The materials used for SiN, AlN, TiN,
SiO ₂ , Al ₂ O ₃ , SiC, TiC, ZnO, SiAl
ON, ITO, and SnO ₂ are suitable, and these materials are formed by magnetron sputtering. The thickness of the nonmagnetic layer 23 is suitably in the range of 50 to 300 °.

The shape of the wobble 3 provided on both sides of the groove G will be described with reference to FIG. In the present invention, the shapes of the wobbles 3 provided on both sides of the groove G need not necessarily be the same. This is for recording a read-only signal in the form of wobbles formed on the walls on both sides of the groove G. Referring to FIG. 6, the wobbles formed on both sides of the groove G may have a sine curve. In FIG.
Although the phases of the sine curves match, the phases may be different.

Further, referring to FIG. 7, the wobbles formed on both sides of the groove G may have a rectangular waveform. Also in FIG. 7, the phases of the wobbles on both sides of the groove G do not match, but may match.
The formation of the wobble is not limited to those shown in FIGS. 5, 6, and 7, but may be other waveforms such as a triangular waveform, or a mixture of a triangular waveform and a rectangular waveform.

Referring to FIG. 8, there is shown a polarization microscope photograph when wobbles are formed on both sides of the groove. In FIG. 8, white portions are grooves, and black portions are lands. FIG. 8 is a photograph when a wobble having a sine curve is formed. It can be seen that the wobble is periodically formed and a polarization signal is recorded. With reference to FIG. 9, an optical system for recording and reproducing information on the above-described magneto-optical recording medium will be described. Optical system wavelength 680 (tolerance ± 15)
a semiconductor laser 91 that generates a laser beam of nm, a collimator lens 92 that converts the laser beam into parallel light, and generates 0th-order and ± 1st-order diffracted light from the laser beam,
Of the generated 0th-order and ± 1st-order diffracted lights, the 0th-order diffracted light (hereinafter referred to as first diffracted light) is applied to the center of the land L or the groove G of the magneto-optical recording medium, and the + 1st order (Hereinafter referred to as second diffracted light) on one wall of the groove G, and -1st-order diffracted light (hereinafter referred to as third diffracted light) on the other wall of the groove G. Diffraction means 93 formed so that the direction of the diffraction grating and the direction of the track form a predetermined angle so as to irradiate, a polarizing beam splitter 94, an objective lens 95, and the laser light is applied to the magneto-optical recording. Of the light reflected on the recording surface of the medium, the polarization beam splitter 94
It comprises a converging lens 96 for converging the reflected light reflected in the direction of the degree, a cylindrical lens 97, and a photodetector 98. Accordingly, the laser light generated by the semiconductor laser 91 is converted into parallel light by the collimator lens 92, and the first, second, and third diffracted lights are diffracted by the diffraction means 93. Is generated, enters the objective lens 95 via the polarizing beam splitter 94, is condensed by the objective lens 95, and is irradiated on the recording film 2 through the light transmitting substrate 1. The first diffracted light, the second diffracted light, and the third
The reflected light of the diffracted light returns to the polarizing beam splitter 94 via the light transmitting substrate 1 and the objective lens 95, and the polarization beam splitter 94 changes the direction to the incident direction.
The light is reflected by being changed to a direction forming 0 degree, and is condensed and irradiated on the photodetector 98 via the focusing lens 96 and the cylindrical lens 97. The second diffracted light and the third diffracted light are The first diffracted light is detected as a push-pull signal and the magneto-optical signal. The angle between the direction of the diffraction grating of the diffraction means 93 and the direction of the track is in the range of 1 to 10 degrees.

The number of diffracted lights applied to the magneto-optical recording medium 10 is not necessarily three, and the first diffracted light applied to the center of the land or the groove and the one diffracted light applied to one wall of the groove. It suffices if there are two diffracted lights including the second diffracted light. In this case, the signal recorded in the groove is reproduced by the first diffracted light, and the signal recorded as a wobble on the left wall of the groove is reproduced by the second diffracted light. Next, when regenerating the land,
The signal recorded on the land is reproduced by the first diffracted light, and the signal recorded as a wobble on the left wall of the land is reproduced by the second diffracted light.

Referring to FIG. 10, a reproducing method of the magneto-optical recording medium will be described. The first diffracted light 104 generated by the diffracting means 93 is at the center of the groove 101, the second diffracted light 106 is on the right wall 103 of the groove 101, and the third diffracted light 105 is Is illuminated on the left wall. The first diffracted light 104 and the second diffracted light 10 generated according to the present invention
6 and the third diffracted light 105 are different from the three beams that are normally generated, and are respectively the + 1st-order diffracted light and −
The center of the second diffracted light 106 corresponding to the first-order diffracted light and the center of the third diffracted light 105 are aligned with the groove 101.
Irradiation is performed so as to be at the positions of the walls 103 and 102 on both sides. Therefore, the signal recorded in the groove 101 and the signal recorded in the form of a wobble on the left and right walls can be reproduced. The reproduction of the signals recorded on the walls on both sides is detected as a difference in light intensity detected between the area 107a and the area 107b of the two-piece sensor 107. On the other hand, a polarization signal is detected as a signal recorded in the groove 101 as a sum of light intensities detected in the area 107a and the area 107b. When the land 109 is reproduced, the center of the land 109 is irradiated with the first diffracted light. In this case, the second diffracted light 106 irradiates the right wall 110 of the land 109 and the third diffracted light 105 irradiates the left wall 103. The signal is not reproduced. That is, the reproduction of the signal recorded in the form of wobble on the walls on both sides of the groove is performed when the first diffracted light is applied to the groove. Will be

The beam is not limited to the light diffracted by the diffraction grating, and the same effect as described above can be obtained by using a plurality of lasers or split prisms. When a plurality of lasers are used, a plurality of semiconductor laser chips are included in the semiconductor laser 91 of FIG. 9 described above, and the plurality of semiconductor laser chips are installed on one straight line in one plane. I have. Therefore, the angle between the direction of the straight line and the direction of the track is in the range of 1 to 10 degrees as described above. In this case, the optical system is an optical system in which the diffraction grating is removed from the optical system shown in FIG. In the present invention, preferably, the semiconductor laser 91 includes two or three semiconductor laser chips.

The signal format will be described with reference to FIG. FIG. 11 shows a signal format when an address is recorded by wobble. The address is recorded twice as GnL on the right wall of the groove, and the address is recorded as GnR on the left wall. Also, fine clock marks (Fine Clock marks) are provided at predetermined intervals.
kMark). This fine clock mark is used for synchronizing signal reproduction.

FIG. 12 shows the recorded address GnL,
5 shows a GnR reproduction signal. It can be seen that the addresses recorded on both sides of the groove as wobbles can be taken out as reproduction signals. FIG. 13 shows a polarization reproduction waveform when the wobble is formed with a sine curve waveform, and FIG. 14 shows a wobble as a biphase waveform in which one sine curve and a sine curve having a period half that of one sine curve are superimposed. 5 is a polarization reproduction waveform in the case. Also in this case, it can be seen that it can be extracted as a reproduction signal.

Referring to FIG. 15, the relationship between the wobble amplitude and the reproduction signal level will be described. As the amplitude of the wobble increases, the level of the polarization reproduction signal increases. In the present invention, an amplitude in the range of 5 to 40 nm is suitable.
Further, in the present invention, the reproduction signal of the signal magnetically recorded on the land or groove is amplified based on the signal intensity of the polarization reproduction signal of the wobble shown in FIG.
That is, as shown in FIG. 16, the signal intensity from the wobble detected by the photodetector 98 is held by the sample and hold circuit 160, and this is held by the AGC (Aut).
o Gain Control) signal as AGC (A
(autoGain Control) circuit 161. The AGC circuit 161 amplifies the magneto-optical signal obtained by the photodetector 98 based on the transmitted AGC signal, and extracts the signal as a reproduction signal. Therefore, since a wobble polarization signal is recorded, signal processing is simplified by using this signal as a reference.

[0029]

According to the present invention, the read-only data can be recorded as a push-pull signal or a polarization signal by wobble, and the rewritable data can be recorded as magnetism. A magneto-optical recording medium in which regions are mixed can be realized.

According to the present invention, a magneto-optical recording medium in which a read-only area and a rewritable area are mixed can be realized, so that the recording capacity of the magneto-optical recording medium can be increased. Further, according to the present invention, it is possible to realize an optical system capable of independently reproducing signals recorded on lands, grooves, and walls on both sides of the grooves. Further, according to the present invention, since the signals recorded on the lands, the grooves, and the walls on both sides of the grooves can be independently reproduced, a large-capacity magneto-optical recording medium capable of recording and reproducing can be realized.

[Brief description of the drawings]

FIG. 1 is a plan view of a magneto-optical recording medium.

FIG. 2 is a perspective view showing the structure of a magneto-optical recording medium.

FIG. 3 is a diagram showing a cross-sectional structure of a magneto-optical recording medium.

FIG. 4 is a diagram showing another cross-sectional structure of the magneto-optical recording medium.

FIG. 5 is a diagram showing a wobble shape.

FIG. 6 is a diagram showing another example of a wobble shape.

FIG. 7 is a diagram showing another example of a wobble shape.

FIG. 8 is a polarization microscope photograph of a magneto-optical recording medium having wobbles formed on both sides of a groove.

FIG. 9 is a diagram illustrating a configuration of an optical system.

FIG. 10 is a diagram illustrating a method of reproducing a polarization, a push-pull signal recorded on a groove, a land, and walls on both sides of the groove.

FIG. 11 is a diagram showing a signal format.

FIG. 12 is a diagram showing a push-pull reproduction signal of a signal recorded as a wobble on the wall on both sides of the groove.

FIG. 13 is a diagram illustrating a polarization reproduction signal of a signal recorded as a wobble having a sine curve waveform.

FIG. 14 is a diagram showing a polarization reproduction signal of a signal recorded as a wobble having a waveform obtained by superimposing one sine curve and a sine curve having a half cycle of one sine curve.

FIG. 15 is a diagram showing the relationship between the amplitude of a wobble and the level of a polarization reproduction signal.

FIG. 16 is a diagram illustrating a mechanism for amplifying a magneto-optical signal.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Substrate 2 ... Recording film 3 ... Wobble 10 ... Magneto-optical recording medium 21 ... Underlayer 22 ... Reproducing layer 23 ... Non-magnetic layer 24 ... Recording layer 25 ... Protective layer 26 ... Ultraviolet curable resin 91 ... Semiconductor laser 92 ... Collimator lens 93 ... Diffraction means 94 ... Polarization beam splitter 95 ... Objective lens 96 ... Converging lens 97 ... Cylindrical lens 98 ... Photodetector 101 ... Gleave 102,103 ... Wobble 104,105,106 ... Diffraction light 109 ... Land

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Jun Yamaguchi 2-5-5 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd.

Claims (23)

[Claims] 1. A recording medium having a track including a land and a groove, wherein a wobble on which signals are recorded is provided on both side walls of the groove, and a recordable material is formed on the surface of the track. 2. The recording medium according to claim 1, wherein the recordable material is a magnetic film. 3. The recording medium according to claim 2, wherein the magnetic film includes a first magnetic layer for recording a signal, and a second magnetic layer to which a signal is transferred from the first magnetic layer. 4. The recording medium according to claim 3, wherein the second magnetic layer is formed in contact with the first magnetic layer. 5. The recording medium according to claim 3, wherein a non-magnetic film is formed between said first magnetic layer and said second magnetic film. 6. The recording medium according to claim 3, wherein the first magnetic layer is made of a perpendicular magnetic film, and the second magnetic layer is made of an in-plane magnetic film. 7. The method according to claim 6, wherein the perpendicular magnetization film is made of TbFeCo or Tb, D
y, Nd and at least one element selected from Fe, C
a single-layer magnetic film or a multilayer magnetic film composed of
a single-layer magnetic film or a multilayer magnetic film composed of at least one element of t and Pd and at least one element selected from Fe, Co, and Ni, wherein the in-plane magnetized film is GdFeCo or GdFe ,
Or GdCo, or TbCo, or Ho,
A recording medium which is a magnetic film including at least one element selected from Gd, Tb, and Dy and at least one element selected from Fe, Co, and Ni. 8. The recording medium according to claim 5, wherein the first magnetic layer is made of a perpendicular magnetic film, and the second magnetic layer is made of an in-plane magnetic film. 9. The method according to claim 8, wherein the perpendicular magnetization film is made of TbFeCo or Tb, D
y, Nd and at least one element selected from Fe, C
a single-layer magnetic film or a multilayer magnetic film composed of at least one element selected from the group consisting of at least one element selected from the group consisting of Pt and Pd and at least one element selected from the group consisting of Fe, Co and Ni. A single-layer magnetic film or a multi-layer magnetic film, wherein the in-plane magnetized film is GdFeCo or GdFe,
Or GdCo, or TbCo, or Ho,
A recording medium which is a magnetic film including at least one element selected from Gd, Tb, and Dy and at least one element selected from Fe, Co, and Ni. 10. The nonmagnetic film according to claim 9, wherein the nonmagnetic film is made of SiN, AlN, or TN.
iN or SiO _TwoOr Al_TwoO_ThreeOr S
iC, or TiC, or ZnO, or Si
AlON, ITO, or SnO_TwoNote that is
Recording medium. 11. The recording medium according to claim 6, wherein the perpendicular magnetization film and the in-plane magnetization film have an amorphous structure. 12. The recording medium according to claim 6, wherein the structure of the perpendicular magnetization film and the structure of the in-plane magnetization film are a polycrystalline or single crystal structure. 13. The recording medium according to claim 1, wherein the shape of the wobble is a sine curve. 14. The recording medium according to claim 1, wherein the wobble has a triangular waveform. 15. The recording medium according to claim 1, wherein the wobble has a rectangular waveform. 16. The recording medium according to claim 13, wherein the wobble has an amplitude in a range of 5 to 40 nm. 17. The recording medium according to claim 1, wherein the signal recorded in the wobble is a read-only signal. 18. A track comprising a land and a groove provided with wobbles recording signals on both side walls,
An objective lens provided to face a recording surface of a recording medium on which a recordable material is formed on the surface of the track; a laser beam generating means for generating a laser beam; Means for generating at least a first diffracted light and a second diffracted light, wherein a grating is formed so as to form a predetermined angle with respect to the track, and the first diffracted light and the second diffracted light are formed. Diffractive means for guiding diffracted light to the objective lens; and light detecting means for detecting reflected light of the first diffracted light and the second diffracted light from the recording surface as a push-pull signal or a magneto-optical signal. Information recording and reproducing device including. 19. A track comprising a land and a groove provided with wobbles recording signals on both side walls,
An objective lens provided to face a recording surface of a recording medium on which a recordable material is formed on the surface of the track; a laser beam generating means for generating a laser beam; Means for generating a first diffracted light, a second diffracted light, and a third diffracted light, wherein a grating is formed so as to form a predetermined angle with respect to the track, and the first diffracted light, Diffracting means for guiding the second diffracted light and the third diffracted light to the objective lens; the first diffracted light, the second diffracted light, and the third diffracted light.
A light detecting means for detecting reflected light of the diffracted light from the recording surface as a push-pull signal or a magneto-optical signal. 20. A track comprising a land and a groove provided with wobbles recording signals on both side walls,
An objective lens provided to face a recording surface of a recording medium having a recordable material formed on the surface of the track; a first semiconductor laser chip for generating a first laser beam;
And a second semiconductor laser chip for generating a second laser light, wherein the first semiconductor laser chip and the second
A laser light generating means arranged such that a direction in which the semiconductor laser chip is arranged and a direction of the track form a predetermined angle; and the first laser light and the second laser light. A collimator lens that receives and converts the received laser light into parallel light and guides the laser light to the objective lens; and a push-pull signal or a magneto-optical signal that reflects reflected light of the first laser light and the second laser light from the recording surface. An information recording / reproducing apparatus including: 21. A track comprising a land and a groove provided with wobbles recording signals on both side walls,
An objective lens provided to face a recording surface of a recording medium having a recordable material formed on the surface of the track; a first semiconductor laser chip for generating a first laser beam;
A second semiconductor laser chip that generates a second laser beam,
And a third semiconductor laser chip for generating a third laser beam, wherein the first semiconductor laser chip and the second
A laser light generating means arranged so that a direction in which the semiconductor laser and the third semiconductor laser chip are arranged and the direction of the track form a predetermined angle; and the first laser light, An information recording / reproducing apparatus including: a light detecting unit configured to detect reflected light of the second laser light and the third laser light from the recording surface as a push-pull signal or a magneto-optical signal. 22. The sample and hold circuit according to claim 17, wherein the sample and hold circuit holds the signal strength of the signal reproduced from the wobble, and receives the signal strength held by the sample and hold circuit as an AGC signal. An information recording / reproducing apparatus including an AGC circuit for amplifying a magneto-optical signal on the basis of a reference. 23. The information recording / reproducing apparatus according to claim 18, wherein the predetermined angle is in a range of 1 to 10 degrees.