JP3427016B2 - Magneto-optical recording medium and method of manufacturing the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magneto-optical recording medium capable of detecting a reference shape for generating a signal recording / reproducing clock in a well-balanced manner by a land and a groove, and a manufacturing method thereof.

[0002]

2. Description of the Related Art Magneto-optical recording media have been attracting attention as rewritable recording media having a large storage capacity and high reliability, and are being put to practical use as computer memories and the like. In addition, recently, the recording capacity is 6.0 Gby.
tes magneto-optical recording medium is AS-MO (Advance
d Storage Magneto Optica
l disk) standard and is about to be put into practical use.

The planar structure of the magneto-optical recording medium according to the AS-MO standard is as shown in FIG.
Grooves and lands are alternately formed in the radial direction 00 (direction perpendicular to the track direction DR1), and the grooves include discontinuous regions 130 composed of lands at regular intervals, and the lands are groove at regular intervals. A discontinuous region 14 consisting of
Including 0. An address area 110 is formed between the adjacent discontinuous areas 130 and 130 of the magneto-optical recording medium 100 and between the adjacent discontinuous areas 140 and 140, and a data area 120 is formed following the address area 110. Has been done.

In the address area 110, address information is recorded on one wall of the groove by the wobble 111, and the same address information as the address information recorded by the wobble 111 is recorded on the other wall of the groove by the wobble 112. ing. In FIG. 20, it is considered that the same address information is recorded by the wobbles 111, 112 on the walls on both sides of each groove 3, 3, ..., However, in reality, one groove 3 and another groove 3 are recorded. The recorded address information is different between 3 and 3.

In the magneto-optical recording medium 100, the length of the discontinuous area 130 in the track direction DR1 is equal to the length of the discontinuous area 140 in the track direction DR1, and the discontinuous areas 130, 140 are so-called tangential push. The pull method is used to generate a clock for recording or reproducing a signal on or from the magneto-optical recording medium 100 based on the detected optical signal.

[0006]

Since the discontinuous region 130 is composed of the land and the discontinuous region 140 is composed of the groove, the length of the discontinuous region 130 and the discontinuous region 140 in the track direction DR1 is small. Equal to discontinuous region 1
There is a difference between the optical signals for detecting 30 and the discontinuous region 140, and a difference occurs in the clock generated when the laser light travels on the land of the magneto-optical recording medium 100 and when it travels on the groove. As a result, there is a problem that accurate signal recording and reproduction cannot be performed.

That is, referring to FIG. 21, translucent substrate 10
S on the discontinuous area 130 composed of land on one main surface
When the dielectric layer 102 made of iN and the magnetic layer 103 made of GdFeCo or the like are formed, the translucent substrate 10
When the discontinuous region 130 is irradiated with laser light from the first side and the reflected light is to be detected, the reflected light is almost reflected at the interface between the dielectric layer 102 and the magnetic layer 103 whose refractive index greatly changes. As a result, the length of the discontinuous area 130 in the track direction DR1 becomes longer than the original length, and the signal (A) is detected when the reflected light from the discontinuous area 130 is detected by the tangential push-pull method.

On the other hand, when the dielectric layer 102 made of SiN and the magnetic layer 103 made of GdFeCo or the like are formed on the discontinuous region 140 made of a groove on one main surface of the transparent substrate 101, the light is transmitted. When laser light is irradiated to the discontinuous region 140 from the side of the flexible substrate 101 and the reflected light is to be detected, the reflected light also changes the refractive index greatly at the interface between the dielectric layer 102 and the magnetic layer 103 in this case as well. Mostly reflected. As a result, the track direction DR of the discontinuous area 140
The length of 1 becomes shorter than the original length, and the discontinuous area 14
When the reflected light from 0 is detected by the tangential push-pull method, the signal (B) is detected.

A clock for recording and reproducing a signal is generated by specifying the center positions C and D of the detected signals (A) and (B) and using the specified positions as a reference.

However, comparing the signal (A) with the signal (B), the slope is steep near the point D, which is the center of the signal (B), and it is easy to identify the point D, which is the center. ) The slope around the point C, which is the center of
It is difficult to identify the points. As a result, when the laser light travels in the groove of the magneto-optical recording medium 100, the signal (A) is detected, and the laser light emits the magneto-optical recording medium 100.
When traveling on the land, the signal (B) is detected, and the clock generated based on the signal (A) and the clock generated based on the signal (B) are different, and recording and reproduction of the signal are accurately performed. The problem is that it is difficult.

Therefore, the present invention solves such a problem, and when the laser light travels on both the land and the groove of the magneto-optical recording medium, the discontinuous area formed on the land and the discontinuous area formed on the groove. It is an object of the present invention to provide a magneto-optical recording medium in which substantially the same optical signals are detected from different areas and the clocks generated from the respective optical signals are the same, and a method for manufacturing the same.

[0012]

According to a first aspect of the present invention, there is provided a light-transmissive substrate in which tracks composed of lands and grooves are formed in a spiral or concentric shape, and formed on the lands and grooves. In the magneto-optical recording medium including a dielectric layer formed on the dielectric layer and a magnetic layer formed on the dielectric layer, the land includes a first discontinuous region including grooves formed at regular intervals, The groove includes a second discontinuous region composed of lands formed at regular intervals, and the first discontinuity is formed at a depth of about one half of the groove forming the first discontinuous region. The length of the region in the track direction is Lg, and the thickness of the dielectric layer in the direction perpendicular to the inclined part of the groove at a depth of approximately ½ of the groove forming the first discontinuous region is d, Inclination of the groove The inclination angle of theta, the second at approximately 1 height half of the lands constituting the second discrete area
When the length in the track direction of the discontinuous area of is Ll,
Lg−2 × (d / sin θ) = Ll + 2 × (d / sin
The magneto-optical recording medium satisfies the relationship of θ).

In the magneto-optical recording medium according to the first aspect, the length in the track direction of the first discontinuous region formed by the groove in the land formed on the transparent substrate is from the land in the groove. It is longer than the length in the track direction of the second discontinuity region. Then, a dielectric layer and a magnetic layer are formed on the first and second discontinuous regions, and the first and second discontinuous regions are formed.
The laser light applied to the discontinuous region of is almost reflected at the interface between the dielectric layer and the magnetic layer. As a result, the length in the track direction of the first discontinuous region detected by the laser light irradiated on the first discontinuous region and the second discontinuity detected by the laser light irradiated on the second discontinuous region. The difference from the length of the continuous area in the track direction is reduced.

Therefore, according to the first aspect of the present invention, the signal obtained by detecting the reflected light from the first discontinuous region by the tangential push-pull method and the reflected light from the second discontinuous region are detected. Is almost the same as the signal detected by the tangential push-pull method, and the generated clocks are almost the same when the laser light travels on the land of the magneto-optical recording medium and when it travels on the groove. Therefore, it is possible to record and reproduce signals on the land and the groove with reference to the same clock.

According to a second aspect of the present invention, there is provided a light-transmissive substrate in which tracks made of lands and grooves are spirally or concentrically formed, a dielectric layer formed on the lands and grooves, and In a magneto-optical recording medium including a magnetic layer formed on a dielectric layer, the land is
The groove includes a first discontinuous region formed of grooves formed at regular intervals, the groove includes a second discontinuous region formed of lands formed at regular intervals, and the first discontinuous region includes The length of the first discontinuous region in the track direction at a depth of approximately one half of the groove that is formed is L.
g, about 2 of the grooves forming the first discontinuous region
The thickness of the dielectric layer in the direction perpendicular to the slanted portion of the groove at a depth of 1 / d, the slanted angle of the slanted portion of the groove is θ, and the land forming the second discontinuous region is approximately 2 If the length of the second discontinuous region in the track direction at a height of 1 / l is Ll, then Lg-2 * (d / sin)
θ) = Ll + 2 × (d / sin θ), which is approximately one half of the groove forming the first discontinuous region.
The radial length of the first discontinuous region at the depth of the second discontinuous region is approximately one-half the height of the land forming the second discontinuous region. The length of the magneto-optical recording medium is longer than the length.

In a magneto-optical recording medium according to a second aspect of the present invention, the lengths of the first discontinuous area formed by the groove in the land formed on the transparent substrate in the track direction and the tracking direction (radial direction). Is longer than the length in the track direction and the tracking direction (radial direction) of the second discontinuous region formed by the land in the groove. Then, a dielectric layer and a magnetic layer are formed on the first and second discontinuous regions,
The laser light applied to the first and second discontinuous regions is almost reflected at the interface between the dielectric layer and the magnetic layer. As a result, the length in the track direction of the first discontinuous region detected by the laser light irradiated on the first discontinuous region and the second discontinuity detected by the laser light irradiated on the second discontinuous region. The difference from the length of the continuous area in the track direction is reduced.
Further, there is almost no difference between the tracking error signal generated from the first discontinuous area and the tracking error signal generated from the second discontinuous area.

Therefore, according to the second aspect of the invention, there is almost no difference in the generated clock between when the laser light travels on the land of the magneto-optical recording medium and when it travels on the groove. There is almost no difference in tracking servo. Therefore, the land and the groove can be similarly irradiated with the laser light, and the recording and the reproduction of the signal can be performed based on the same clock.

According to a third aspect of the present invention, there is provided a light-transmissive substrate in which tracks made of lands and grooves are spirally or concentrically formed, a dielectric layer formed on the lands and grooves, and In a magneto-optical recording medium including a magnetic layer formed on a dielectric layer, the land is
The groove includes a first discontinuous area formed at regular intervals, and the groove has second discontinuous areas formed at regular intervals and at least one of the walls has address information. And a wobble that is approximately 1/2 of the groove that constitutes the first discontinuous region.
Lg is the length of the first discontinuous region in the track direction at a depth of, and the sloped portion of the groove of the dielectric layer is at a depth of approximately ½ of the groove forming the first discontinuous region. The thickness in the direction perpendicular to the groove, the inclination angle of the inclined portion of the groove is θ, and the track of the second discontinuous region at a height of approximately one half of the land that constitutes the second discontinuous region. When the length in the direction is L1, Lg-2 × (d /
sin θ) = Ll + 2 × (d / sin θ) holds, and the wobble has a first wavelength wobble that is convex toward the land adjacent to the wall of the groove in which the wobble is formed, and the first wobble. The second convex on the side opposite to the wobble of the wavelength
And a wobble having a wavelength of, wherein the first wavelength is longer than the second wavelength.

In the magneto-optical recording medium according to a third aspect of the present invention, the length in the track direction of the first discontinuous region formed by the groove in the land formed on the transparent substrate is from the land in the groove. It is longer than the length in the track direction of the second discontinuity region. Further, the wobble formed in the groove, which is address information, has a long wavelength in a region that is convex on the adjacent land side and a short wavelength in a region that is convex on the opposite side. Then, a dielectric layer and a magnetic layer are formed on the first and second discontinuous regions, and the laser light applied to the first and second discontinuous regions is almost reflected at the interface between the dielectric layer and the magnetic layer. To be done. In addition, a dielectric layer and a magnetic layer are formed on a wobble having a long wavelength and a wobble having a short wavelength,
The laser light applied to the area where the wobble is formed is almost reflected at the interface between the dielectric layer and the magnetic layer.

As a result, the length in the track direction of the first discontinuous area detected by the laser light irradiated on the first discontinuous area and the first length detected by the laser light irradiated on the second discontinuous area. The difference from the length in the track direction of the two discontinuous areas becomes small. Further, the reflected light from the wobble can be detected as the reflected light from the wobble having a uniform wavelength.

Therefore, according to the invention described in claim 3, a signal obtained by detecting the reflected light from the first discontinuous region by the tangential push-pull method and the reflected light from the second discontinuous region are detected. Is almost the same as the signal detected by the tangential push-pull method, and the generated clocks are almost the same when the laser light travels on the land of the magneto-optical recording medium and when it travels on the groove. Therefore, it is possible to record and reproduce signals on the land and the groove with reference to the same clock.

Further, the address information can be accurately detected.

According to a fourth aspect of the invention, there is provided a light-transmissive substrate in which tracks composed of lands and grooves are spirally or concentrically formed, a dielectric layer formed on the lands and grooves, and In a magneto-optical recording medium including a magnetic layer formed on a dielectric layer, the land is
The groove includes a first discontinuous area formed at regular intervals, and the groove has second discontinuous areas formed at regular intervals and at least one of the walls has address information. And a wobble that is approximately 1/2 of the groove that constitutes the first discontinuous region.
Lg is the length of the first discontinuous region in the track direction at a depth of, and the sloped portion of the groove of the dielectric layer is at a depth of approximately ½ of the groove forming the first discontinuous region. The thickness in the direction perpendicular to the groove, the inclination angle of the inclined portion of the groove is θ, and the track of the second discontinuous region at a height of approximately one half of the land that constitutes the second discontinuous region. When the length in the direction is L1, Lg-2 × (d /
sin θ) = Ll + 2 × (d / sin θ) holds, and approximately 2 of the grooves forming the first discontinuous region are formed.
The radial length of the first discontinuous region at a depth of one half is such that the second discontinuous region is at a height that is approximately one half of the land forming the second discontinuous region. Longer than the radial length of the wobble, the wobble has a first wavelength wobble that is convex toward the land adjacent to the wall of the groove in which the wobble is formed, and a wobble that is opposite to the wobble of the first wavelength. And a wobble of a second wavelength, which is a magneto-optical recording medium in which the first wavelength is longer than the second wavelength.

In the magneto-optical recording medium according to the fourth aspect, the length in the track direction and the tracking direction (radial direction) of the first discontinuous region formed by the groove in the land formed on the transparent substrate. Is longer than the length in the track direction and the tracking direction (radial direction) of the second discontinuous region formed by the land in the groove. Further, the wobble formed in the groove, which is address information, has a long wavelength in a region that is convex on the adjacent land side and a short wavelength in a region that is convex on the opposite side. Then, a dielectric layer and a magnetic layer are formed on the first and second discontinuous regions, and the laser light applied to the first and second discontinuous regions is almost reflected at the interface between the dielectric layer and the magnetic layer. To be done. Further, a dielectric layer and a magnetic layer are formed on a wobble having a long wavelength and a wobble having a short wavelength, and the laser light irradiated to the area where the wobble is formed is almost reflected at the interface between the dielectric layer and the magnetic layer. It

As a result, the length in the track direction of the first discontinuous region detected by the laser light emitted to the first discontinuous region and the first length of the laser beam irradiated to the second discontinuous region are detected. The difference from the length in the track direction of the two discontinuous areas becomes small. Further, there is almost no difference between the tracking error signal generated from the first discontinuous area and the tracking error signal generated from the second discontinuous area. Further, the reflected light from the wobble can be detected as the reflected light from the wobble having a uniform wavelength.

Therefore, according to the invention described in claim 4, there is almost no difference in the generated clock between when the laser light travels on the land of the magneto-optical recording medium and when it travels on the groove. There is almost no difference in tracking servo. Therefore, the land and the groove can be similarly irradiated with the laser light, and the recording and the reproduction of the signal can be performed based on the same clock. Further, the address information can be accurately detected.

[0027]

[0028]

[0029]

[0030]

[0031]

[0032]

[0033]

[0034]

[0035]

[0036]

[0037]

[0038]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described with reference to the drawings. With reference to FIG. 1, a planar structure of a translucent substrate 10 constituting the magneto-optical recording medium according to the present invention will be described. The translucent substrate 10 has a planar structure in which the grooves 3 and the lands 4 are alternately formed in the tracking direction (direction perpendicular to the track direction DR1, hereinafter the same). The grooves 3 are formed from the lands at regular intervals. The land 4 has a discontinuous region 6 formed of grooves at the same intervals as the discontinuous region 5. The discontinuous areas 5 and 6 serve as a reference for generating a clock when recording or reproducing a signal on the magneto-optical recording medium, and the length of the discontinuous area 5 in the track direction DR1 is discontinuous. It is shorter than the length of the area 6 in the track direction DR1. The widths of the groove 3 and the land 4 in the tracking direction are the same and are about 0.6 μm. The interval at which the discontinuous regions 5 and 6 are formed is about 120 μm.

The transparent substrate 10 has an address area 1 and a data area 2. In the address area 1, address information is recorded by wobbles 111 and 112 on the wall of the groove 3. The wobbles 111 and 112 have the same address information, are formed on the walls of the grooves 3 on the opposite sides, and do not face one wobble. This address information recording method is called a one-sided stagger method. By recording the address information by the one-sided stagger method, the address information can be accurately detected even when the transparent substrate 10 is tilted due to tilting or the like and the irradiation position of the laser light is deviated from the center of the land or groove. In FIG. 1, it is considered that the same address information is recorded by the wobbles 111 and 112 on the walls on both sides of each groove 3, 3, ..., However, in reality, one groove 3 and another groove 3 are recorded. The recorded address information is different between 3 and 3.

FIG. 2 shows a sectional structure in the track direction DR1 near the discontinuous regions 5 and 6. A dielectric layer 12 made of SiN is formed on the discontinuous region 5 made of lands formed on the transparent substrate 10, and a magnetic layer 13 made of GdFeCo or the like is formed on the dielectric layer 12.
Are formed. Further, the dielectric layer 12 and the magnetic layer 13 are also formed on the discontinuous region 6 formed of the groove formed on the transparent substrate 10.

Referring to FIG. 3, the magnetic layer 13 is made of GdFe.
It has a sectional structure in which a reproducing layer 131 made of Co, a non-magnetic layer 132 made of SiN, and a recording layer 133 made of TbFeCo are sequentially deposited from the dielectric layer 12 side.

Therefore, the reproducing layer 131 is the transparent substrate 10.
Since it is located on the side, the laser beam is irradiated from the transparent substrate 10 side, the magnetic domain of the recording layer 133 is transferred to the reproducing layer 131 via the non-magnetic layer 132, and the transferred magnetic domain is detected by the laser beam. The signal is reproduced by. Further, at the time of recording a signal, it is necessary to apply a magnetic field of a predetermined intensity to the magnetic layer 13, so a magnetic head (not shown) is arranged on the recording layer 133 side. Therefore, the laser light is emitted from the side of the transparent substrate 10 even when the signal is recorded.

Referring again to FIG. 2, when laser light is irradiated to the discontinuous region 5 from the transparent substrate 10 side, the interface between the dielectric layer 12 and the magnetic layer 13 is caused by the difference in refractive index. Is reflected by the tangential push-pull method, a signal (LS) is detected, and when the laser light is applied to the discontinuous region 6, the dielectric layer is caused by the difference in refractive index. Almost reflected at the interface between the magnetic layer 12 and the magnetic layer 13, and when the reflected light is detected by the tangential push-pull method, a signal (GS) is detected. The lengths of the signal (LS) and the signal (GS) in the track direction DR1 are both the same as Lgl, and the inclination near point A which is the center of the signal (LS) and the center B of the signal (GS). The slope around the point is almost the same. Therefore, since the points A and B can be specified in the same manner, a reference signal for generating a clock can be similarly generated when the laser light travels in the groove and when the laser light travels in the land.

The length of the discontinuous regions 5 and 6 formed on the transparent substrate 10 in the track direction DR1 will be described with reference to FIG. Let H be the height of the discontinuous region 5 composed of lands, and in the direction perpendicular to the slope of the discontinuous region 5 of the dielectric layer 12 at a height (H / 2) of half the height H. If the film thickness is d and the inclination angle of the discontinuous region 5 is θ,
The film thickness x of the dielectric layer 12 in the track direction DR1 at a height of half the height H is x = d / sin θ. Therefore, when the length in the track direction DR1 at the height H / 2 of the discontinuous region 5 formed on the transparent substrate 10 is Ll, the length Lgl between the E point and the F point is Lgl = Ll + 2d / sin θ (1) (see FIG. 4A).

On the other hand, the depth of the discontinuous region 6 made of a groove is H, and the slope of the discontinuous region 6 of the dielectric layer 12 at a depth (H / 2) of half the depth H. Assuming that the film thickness in the direction perpendicular to the direction is d and the inclination angle of the discontinuous region 6 is θ, the film thickness x of the dielectric layer 12 in the track direction DR1 at the depth H / 2 is x = d / sin θ. Become. Therefore, the depth H / 2 of the discontinuous region 6 formed in the translucent substrate 10 is
Let Lg be the length in the track direction DR1 at G
The length Lgl between the point and the H point is Lgl = Lg-2d / sin θ (2) (see (b) of FIG. 4).

Therefore, in the present invention, the length Ll in the track direction DR1 at the height H / 2 of the discontinuous region 5 formed on the transparent substrate 10 and the non-continuity formed on the transparent substrate 10. Between the length Lg of the continuous region 6 at the depth H / 2 in the track direction DR1 is Ll + 2d / sin θ = Lg-2d / sin θ (3) That is, Lg-Ll = 4d / sin θ ... (4) The following relationship is established.

Referring to FIG. 5, the film thickness of the dielectric layer 12 at a height that is ½ of the height H of the discontinuous region 5 and the depth H of the discontinuous region 6 is ½. In consideration of the film thickness of the dielectric layer 12 at the depth, the length L1 of the discontinuous region 5 formed in the transparent substrate 10 in the track direction DR1 and the length of the discontinuous region 6 formed in the track direction DR1. The reason why Lg is determined will be described. Area D where the focused spot diameter of the laser light does not change when the laser light is irradiated from the transparent substrate 10 side
Since P is equal to or higher than the height H of the discontinuous area 5 and the depth H of the discontinuous area 6, the height H of the discontinuous area 5 is half or more. Depth H of continuous area 6
It is considered that the intensity of the reflected light from a depth of 1/2 of the above becomes dominant. Therefore, the film thickness of the dielectric layer 12 at a height that is ½ of the height H of the discontinuous region 5, and the dielectric layer at a depth that is ½ of the depth H of the discontinuous region 6. 12
The length Ll of the discontinuous region 5 formed in the transparent substrate 10 in the track direction DR1 and the length Lg of the discontinuous region 6 formed in the track direction DR1 are determined in consideration of the film thickness of Is.

In Japanese Unexamined Patent Publication No. 10-261242, a dielectric layer and a magnetic layer are deposited on the groove and the land, and the translucency so that the width of the groove and the width of the land on the magnetic layer are the same. It is described that a groove and a land having different widths are formed on a substrate.
In Japanese Patent Application Laid-Open No. 0-261242, attention is paid to making the width of the groove and the width of the land on the magnetic layer the same, whereas in the present invention, the dielectric layer and the magnetic layer formed on the translucent substrate are used. In view of the large proportion of laser light reflected at the interface with the layer, the length in the track direction DR1 of the discontinuous region 5 made of lands at the interface between the dielectric layer and the magnetic layer and the discontinuity made of the groove. Track direction D in area 6
The two are completely different in that they try to make the length of R1 the same.

In Japanese Patent Laid-Open No. 10-261242, the difference between the film thickness of the magnetic layer on the flat surface of the land and the film thickness of the inclined portion of the land in the normal direction of the magneto-optical recording medium is used as a standard. Then, the width of the groove and the width of the land on the magnetic layer are made the same. On the other hand, according to the present invention, the dielectric layer 1 in the direction perpendicular to the inclined portion of the discontinuous region 5 composed of lands.
The film thickness of 2 or the film thickness of the dielectric layer 12 in the direction perpendicular to the slope of the discontinuous region 6 composed of a groove, and the length in the track direction DR1 of the discontinuous region 5 composed of lands, The two are completely different in that the length of the discontinuous area 6 formed of the groove is made equal to the length in the track direction DR1.

The discontinuous areas 5 and 6 also serve as a reference for generating a tracking error signal when the laser light is applied to the center of the groove and the land. Therefore, preferably, in the transparent substrate 10 shown in FIG. 1, not only the length in the track direction but also the length in the tracking direction is tracked in a discontinuous region composed of grooves formed at regular intervals on the land 4. It includes the groove 3 which forms a discontinuous region shorter than the length in the direction. In this case, the difference between the length in the tracking direction of the discontinuous area formed in the groove 3 at regular intervals and the length in the tracking direction of the discontinuous area formed in the lands 4 at regular intervals is This is the same difference as the length difference 4d / sin θ in the track direction shown by (4). By forming a discontinuous area having such a difference in length in the groove 3 and the land 4, the tracking error signal detected due to the discontinuous area when the laser light travels in the groove 3 and the laser light When traveling on the land 4, the tracking error signal detected due to the discontinuous area can be made substantially the same, and the center of the groove 3 and the center of the land 4 can be irradiated with laser light.

In the present invention, the transparent substrate is the same as that shown in FIG.
The transparent substrate 10 shown in FIG. 6 may be used instead of the transparent substrate 10 shown in FIG. The transparent substrate 20 is the transparent substrate 1
The wobbles 111 and 112 of 0 are changed to the wobbles 7 and 8, and the others are the same as those of the translucent substrate 10. In FIG. 6, it is considered that the same address information is recorded by the wobbles 7 and 8 on the walls on both sides of each groove 3, 3, ..., However, in reality, one groove 3 and another groove 3 are recorded. The recorded address information is different between 3 and 3.

Referring to FIG. 7, the wobble 7 has a wavelength of λ1.
Address information is recorded by forming a wobble 70 having a wavelength λ, which is composed of a wobble 71 and a wobble 72 having a wavelength λ2 shorter than the wavelength λ1, on one wall of the groove 3 in the track direction DR1. In this case, wobble 7
Reference numeral 1 is convex on the land 4 side adjacent to one side of the groove 3, and wobble 72 is convex on the side opposite to the wobble 71. Therefore, since the area 73 surrounded by the wobbles 71 is lower than the area 74 surrounded by the wobbles 72, the dielectric layer 12 and the magnetic layer 13 are formed on the wobbles 71 and 72, and the wobbles 71 and 72 are formed. When the laser light is irradiated from the transparent substrate 20 side, the wobble shape reflected on the reflected light is not the shape of the wobbles 71 and 72, but the dielectric at a depth of half the depth H of the groove 3. Layer 12
Of the interface shape between the magnetic layer 13 and the magnetic layer 13 and the height H of the land 3
It is the interface shape between the dielectric layer 12 and the magnetic layer 13 at a height of a half. Therefore, this relationship is similar to that described with reference to FIG. 4, and between the wavelengths λ1 and λ2, λ1-2d / sin θ = λ2 + 2d / sin θ (5) That is, λ1- The relationship of λ2 = 4d / sin θ (6) holds.

On the other hand, a wobble 8 is formed on the other wall of the groove 3, and the wobble 8 records the same address information as the address information recorded by the wobble 7. The wobble 8 has a wobble 80 having a wavelength λ, which is composed of a wobble 81 having a wavelength λ2 and a wobble 82 having a wavelength λ1 longer than the wavelength λ2, and is formed on the other wall of the groove 3 in the track direction DR1. in this case,
Since the relationship between the area 83 surrounded by the wobble 81 and the area 84 surrounded by the wobble 82 is the same as the relationship between the area 74 and the area 73, the wavelength λ2 of the wobble 81 forming the wobble 80. And the wavelength λ1 of the wobble 82 have the same relationship as the above equation (6). Therefore,
By making the wavelength of the wobble convex to the land 4 side longer than the wavelength of the wobble convex to the groove 3 side, the transparent substrate 2
The wobble detection signal when the wobble is irradiated with laser light from the 0 side can be detected as the detection signal from the wobble having a uniform wavelength.

In the present invention, the transparent substrate may be the transparent substrate 30 shown in FIG. Translucent substrate 30
6 changes the discontinuous area 5 of the transparent substrate 20 shown in FIG. 6 into a discontinuous area 50, and discontinuous area 6 becomes discontinuous area 6
The transparent substrate 20 is the same as the transparent substrate 20 except that the transparent substrate 20 is replaced by 0.

Discontinuous area 50 formed in groove 3
Has a length in the track direction DR1 shorter than the length of the discontinuous region 60 formed in the land 4 in the track direction DR1, and is shorter than the length of the discontinuous region 60 formed in the land 4 in the tracking direction. Directional length. That is, the discontinuous area 50 is the track direction DR.
1 and the discontinuous area 60 in the tracking direction
It is shorter. By adopting such discontinuous regions 50 and 60, a signal serving as a reference for generating a clock can be detected uniformly in the groove 3 and the land 4, and
Tracking servo to the groove 3 and the land 4 can be performed uniformly.

Referring to FIG. 9, translucent substrates 10, 20,
A master cutting device for producing 30 will be described. The master cutting device includes a motor 91 for rotating a circular glass substrate 90 serving as a master, a motor driver 92 for driving the motor 91, and a first laser 93 for generating a laser beam for irradiating the glass substrate 90. , A second laser 94, a first laser drive circuit 166 that first drives the laser 93, a second laser drive circuit 167 that drives the second laser 94, and a laser beam from the first laser 93. A first deflector 95 that deflects and a second deflector 96 that deflects the laser light from the second laser 94.
A reflection mirror 98 that reflects the laser light from the second deflector 96 in the normal direction of the glass substrate 90; and a reflection mirror that reflects the laser light from the first deflector 95 in the normal direction of the glass substrate 90. The mirror 97 that transmits the laser light from the mirror 98 and the objective lens 99 that focuses the two laser lights from the mirror 97 on the surface of the glass substrate 90 are provided.

To manufacture a master for a zone CAV type magneto-optical recording medium, the motor 91 rotates the glass substrate 90 so that the linear velocity of the glass substrate 90 is constant between the zones. As the first laser 93 and the second laser 94, for example, an argon laser that generates laser light having a wavelength of 457.9 nm is used. Regarding the diameter of the laser light, for example, the diameter φrad in the radial direction is 0.6 μm and the diameter φtan in the tangential direction is 0.3 μm. The power of the laser light is usually 30 mW.

The first deflector 95 has an input voltage VI.
The second deflector 96 changes the deflection angle of the laser light according to 1, and the second deflector 96 changes the deflection angle of the laser light according to the input voltage VI2. For example, a crystal of ADP is used. The ADP crystal has a characteristic that the distribution gradient of the refractive index continuously changes depending on the input voltage.

The cutting device for the master of the magneto-optical recording medium further includes the input voltage VI of the first deflector 95.
A first interface 150, which receives a data signal from the outside to generate 1, and a first interface 15
The data signal DT1 input through 0
For example, bi-phase modulation method, NRZI (NonRe
turn zero inverted) plus a first encoder 151 for encoding according to a modulation scheme, and a first carrier generator 152 for generating a carrier signal CR1.
A first amplitude modulator 153 for modulating the amplitude of the carrier signal CR1 in response to the fine clock mark signal FCM1 encoded by the first encoder 151;
Modulation signal MD11 modulated by the amplitude modulator 153
A first amplifier 154 that amplifies R, a first rectifier 155 that rectifies the modulated signal MD12 amplified by the first amplifier 154, and a rectified signal RC1 rectified by the first rectifier 155 with a constant offset added to the cutting data. A first offset device 156 for generating the signal CD1,
In order to generate the input voltage VI1 for supplying the first deflector 95 in response to the cutting data signal CD1 and the input voltage VI2 for the second deflector 96, a data signal is externally supplied. A second interface 158 for accepting, and a second
Data signal D input through interface 158
T2 is a predetermined system, for example, bi-phase modulation system, N
RZI (Non Return Zero Inver)
sed) a second encoder 159 that encodes according to a plus modulation method and a second encoder that generates a carrier signal CR2
The carrier generator 160, the second amplitude modulator 161 that modulates the amplitude of the carrier signal CR2 in response to the fine clock mark signal FCM2 encoded by the second encoder 159, and the second amplitude modulator 161 modulate A second amplifier 162 for amplifying the modulation signal MD21;
Modulated signal MD22 amplified by the second amplifier 162
In response to the second rectifier 163 for rectifying, the second offset 164 for adding a constant offset to the rectified signal RC2 rectified by the second rectifier 163 to generate the cutting data signal CD2, and the second rectifier 164 for responding to the cutting data signal CD2. A second deflector driver 165 that generates an input voltage VI2 for supplying to the second deflector 96.
And a microcomputer 17 for controlling the entire device
With 0 and.

First and second encoders 151, 159
Generates fine clock mark signals FCM1 and FCM2 (a) as shown in FIG. 10, for example. First
And the second carrier generators 152 and 160 generate square-wave carrier signals CR1 and CR2 as shown in FIG. 10B, for example. In addition, the first and second carrier generators 152 and 160 have a square-wave carrier signal C.
Instead of R1 and CR2, triangular wave carrier signals CR1 and CR2 as shown in FIG.
Sinusoidal carrier signal CR as shown in (d) of
1, CR2 may be generated.

The first and second rectifiers 155, 163 are
For example, it is composed of a diode 171 as shown in FIG. First and second deflector driver 15
7 and 165 are the cutting data signals C from the first offset device 156 and the second offset device 164.
Since D1 and CD2 are weak, the cutting data signals CD1 and CD2 are amplified so that the first and second deflector drivers 157 and 165 can be driven, respectively.

Next, the operation of producing the master of the magneto-optical recording medium having the above-mentioned structure will be described. In the first amplitude modulator 153, the amplitude of the square-wave carrier signal CR1 is modulated in response to the fine clock mark signal FCM1 as shown in FIG. 12, and the modulation signal MD11 is generated.

Then, in the first amplifier 154, the modulation signal MD11 is amplified and a modulation signal MD12 having an amplitude larger than that of the modulation signal MD11 is generated.

Subsequently, in the first rectifier 155, the modulated signal MD12 is rectified and the rectified signal RC1 is generated. That is, the first rectifier 155, specifically, the diode 171 blocks a portion of the modulation signal MD12 having a negative voltage.

Then, in the first offset device 156, a constant offset (± X volts) is added to the rectified signal RC1.
Is added to generate a cutting data signal CD1.

Then, this cutting data signal CD
An input voltage VI1 proportional to 1 is supplied from the first deflector driver 157 to the first deflector 95.

Further, in the second amplitude modulator 161,
As shown in FIG. 13, the amplitude of the square-wave carrier signal CR2 is modulated in response to the fine clock mark signal FCM2, and the modulation signal MD21 is generated.

Then, in the second amplifier 162, the modulation signal MD21 is amplified and a modulation signal MD22 having an amplitude larger than that of the modulation signal MD21 is generated.

Then, in the second rectifier 163, the modulated signal MD22 is rectified and the rectified signal RC2 is generated. That is, the second rectifier 163, specifically, the diode 171 blocks a portion of the modulation signal MD22 having a positive voltage.

Then, in the second offset device 164, a constant offset (± X volt) is applied to the rectified signal RC2.
Is added to generate a cutting data signal CD2.

Then, this cutting data signal CD
An input voltage VI2 proportional to 2 is supplied from the second deflector driver 165 to the second deflector 96.

When the input voltage VI1 proportional to the cutting data signal CD1 as shown in FIG. 12 is supplied to the first deflector 95, the first deflector 95 receives the laser beam from the first laser 93 as its input. Voltage VI1
Deflection in response to. In addition, the input voltage VI2 proportional to the cutting data signal CD2 as shown in FIG.
Are supplied to the second deflector 96, the second deflector 96 deflects the laser light from the second laser 94 in response to the input voltage VI2. Here, it is necessary to deflect the laser light from the first laser 93 and the second laser 94 so that the laser light irradiated onto the glass substrate 90 repeatedly reciprocates in the radial direction of the glass substrate 90.

Referring to FIG. 14, the first deflector 9
Laser light generated from the first and second lasers 93 and 94 in synchronism with the timing when the amplitudes of the cutting data signal CD1 input to the signal 5 and the cutting data signal CD2 input to the second deflector 96 increase. Drive signal (e) for increasing the intensity of the signal is input from the microcomputer 170 to the first and second laser drive circuits 166 and 167, and the first and second laser drive circuits 166 and 167 drive the drive signal (e). On the basis of,
The first laser 93 and the second laser 94 are driven, respectively. Then, the first and second lasers 93, 94
Has a normal intensity of 30 mW and 45 m in a region where the amplitudes of the cutting data signals CD1 and CD2 are large.
Laser light having an intensity of W is generated (see (f) in FIG. 14).

When the glass substrate 90 is irradiated with two laser beams, the two laser beams cut the groove 3 while reciprocating in the opposite radial directions of the glass substrate 90. That is, referring to FIG. 15, the laser beam LB1 generated from the first laser 93 keeps the intensity of 30 mW and reciprocates in the radial direction DR2 of the glass substrate 90 to follow the locus 180 of the glass substrate 90. When moving to the track direction DR1 and reaching the position where the discontinuous regions 5 and 6 are formed, the laser beam LB1 moves to the position where the land 4 located in the radial direction DR2 of the groove 3 is to be formed. Then, at the same time as the movement, the intensity is changed from 30 mW to 4
The laser beam LBI1 increased to 5 mW is converted into the laser beam LBI1, and the laser beam LBI1 travels in the track direction DR1 for a predetermined period, and is discontinuous region 6
When the position where the formation of the groove ends is reached, the groove 3 moves to the position where the groove should be formed, and at the same time, the strength is increased to 45 mW.
To 30 mW, and returns to the laser beam LB1. After that, it proceeds in the track direction DR1. Further, the laser beam LB2 generated from the second laser 94 has an intensity of 30 mW.
While holding the locus 1, while reciprocating in the radial direction DR2 of the glass substrate 90 in the direction opposite to the laser beam LB1, the trajectory 1
81 is moved in the track direction DR1 of the glass substrate 90,
At the position where the discontinuous regions 5 and 6 are formed, the laser beam LB2 moves to the position where another land 4 located in the direction opposite to the radial direction DR2 of the groove 3 is to be formed. Then, at the same time as the movement, the intensity is changed from 30 mW to 4
The laser beam LBI2 increased to 5 mW is converted into the laser beam LBI2, which travels in the track direction DR1 for a predetermined period, and is discontinuous region 6
When the position where the formation of the groove ends is reached, the groove 3 moves to the position where the groove should be formed, and at the same time, the strength is increased to 45 mW.
To 30 mW, and returns to the laser beam LB2. After that, it proceeds in the track direction DR1.

As a result, the length in the track direction DR1 of the discontinuous area 5 composed of lands formed in the groove 3 at regular intervals is set to be the discontinuous area composed of grooves formed in the lands 4 at regular intervals. 6 in the track direction DR1 to make the groove 3 and the land 4 in the radial direction D.
It is possible to fabricate masters formed alternately on R2.

The discontinuous regions 50 and 60 shown in FIG.
In order to cut the master disk having the following, cutting data signals CD11 and CD21 as shown in FIG. 16 are generated, and the first deflector 95 and the second deflector 95 of FIG.
Is input to the deflector 96. Since the same drive signal (e) as in the case of FIG. 14 is input to the first and second laser drive circuits 166 and 167, the laser light generated from the first and second lasers 93 and 94 is The intensity change is also the same as in the case of FIG. However, of the cutting data signals CD11 and CD21, the amplitude of the area where the amplitude is large is the cutting data signals CD1 and CD21.
2 is smaller than that of the first and second lasers 9
Region 50 in which the laser light generated from 3, 94 is discontinuous,
The distance moved in the radial direction DR2 to form 60 is smaller than in the case of FIG. That is, when the glass substrate 90 is cut based on the cutting data signals CD11 and CD21 shown in FIG. 16, the laser beam LB1 generated from the first laser 93 maintains the intensity of 30 mW and the radius of the glass substrate 90. While reciprocating in the direction DR2, the locus 185 follows the track direction D of the glass substrate 90.
When the laser beam LB1 moves to R1 and reaches the position where the discontinuous regions 50 and 60 are formed, the laser beam LB1 is directed in the radial direction D of the groove 3.
The land 4 located at R2 moves to the position where it should be formed. In this case, the distance moved in the radial direction DR2 is as shown in FIG.
Shorter than the case of 5. And at the same time as that movement
When the laser beam LBI1 is increased from 0 mW to 45 mW, travels in the track direction DR1 for a predetermined period, and reaches the position where the formation of the discontinuous region 60 ends, the groove 3 moves to the position where the groove 3 should be formed. , And at the same time reduce the intensity from 45mW to 30mW
Return to 1. After that, it proceeds in the track direction DR1. In addition, the laser beam LB2 generated from the second laser 94
Moves the locus 186 in the track direction DR1 of the glass substrate 90 while reciprocating in the radial direction DR2 of the glass substrate 90 in the direction opposite to the laser beam LB1 while maintaining the intensity of 30 mW, and the discontinuous region 50, When the position 60 is formed, the laser beam LB2 moves to a position where another land 4 located in the direction opposite to the radial direction DR2 of the groove 3 is to be formed. Also in this case, the radial direction DR2
The distance to move to is shorter than in the case of FIG. Then, at the same time as the movement, the laser beam LBI2 whose intensity is increased from 30 mW to 45 mW is converted into the laser beam LBI2, which advances in the track direction DR1 for a predetermined period to reach the position where the formation of the discontinuous region 60 ends. The laser beam moves to the position where it should be formed, and at the same time, the intensity is reduced from 45 mW to 30 mW and the laser beam LB2 is returned. After that, it proceeds in the track direction DR1.

As a result, the length in the track direction DR1 of the discontinuous area 50 composed of lands formed at regular intervals in the groove 3 is set to be the discontinuous area composed of grooves formed at regular intervals in the land 4. 60 track direction DR
The length in the tracking direction DR2 of the discontinuous region 50 formed of lands formed at regular intervals in the groove 3 is also made shorter than the length of 1. It is possible to manufacture a master in which the groove 3 and the land 4 are alternately formed in the radial direction DR2 by making the length shorter than the length of the region 60 in the tracking direction DR2.

To cut the master having the wobbles 7 and 8 shown in FIG. 7, the cutting data signals CD12 and CD22 shown in FIG. 18 are used. The cutting data signals CD12 and CD22 are input to the first deflector 95 and the second deflector 96 of FIG. 9, respectively. The drive signal (g1) is input to the first laser drive circuit 166 from the microcomputer 170, and the drive signal (g1) is input to the second laser drive circuit 167.
2) is input from the microcomputer 170. In this case, the drive signal (g1) is a drive signal that changes the intensity of the laser light according to the amplitude variation of the cutting data signal CD12, and the drive signal (g2) is the laser signal according to the amplitude variation of the cutting data signal CD22. This is a drive signal that changes the intensity of light.

The first laser drive circuit 166 drives the first laser 93 based on the drive signal (g1), and the first laser 93 generates laser light having the intensity change shown in (h1) of FIG. To do. Further, the second laser drive circuit 167 drives the second laser 94 based on the drive signal (g2), and the second laser 94 generates the laser light having the intensity change shown in (h2) of FIG. .

With reference to FIG. 19, the laser light generated from the first laser 93 reciprocates in the radial direction DR2 of the glass substrate 90 while changing the intensity shown in (h1) of FIG. The path 190 is moved in the track direction DR1 of the glass substrate 90. In this case, when the wobble 71 is formed, it is changed to the laser beam LBI1 having the intensity of 45 mW, and when the wobble 72 is formed and when the wobble is formed, the laser beam L having the intensity of 30 mW is formed.
It becomes B1. The laser light generated from the second laser 94 changes in intensity as shown in (h2) of FIG. 18, while the laser light LB1 is emitted in the radial direction DR2 of the glass substrate 90.
The locus 191 is moved in the track direction DR1 of the glass substrate 90 while reciprocating in the opposite direction. In this case, when the wobble 82 is formed, it is changed to the laser beam LBI2 having the intensity of 45 mW, and when the wobble 81 is formed and when the wobble is formed, the laser beam LB2 has the intensity of 30 mW. Thereby, as shown in FIG. 7, the groove 3 having the wobbles 7 and 8 on both side walls can be cut.

In order to manufacture the translucent substrate 10 shown in FIG. 1, the translucent substrate 20 shown in FIG. 6 is manufactured by using the master cut by the cutting method described with reference to FIGS. The above-mentioned FIGS.
The transparent substrate 30 shown in FIG. 8 is formed by using the master cut by the cutting method described with reference to FIGS.
In order to fabricate, the master disk cut by the cutting method described with reference to FIGS. 16, 17, 18, and 19 is used.

Then, the transparent substrates 10, 20 and 30 are manufactured using the respective masters, and then the transparent substrates 10 and 2 are prepared.
S on the surface where the grooves 3 and lands 4 of 0 and 30 are formed
A dielectric layer 12 made of iN is deposited by a sputtering method, and a reproducing layer 1 made of GdFeCo is formed on the dielectric layer 12.
31, non-magnetic layer 132 made of SiN, and TbFe
A recording layer 133 made of Co is sequentially deposited by a sputtering method to manufacture a magneto-optical recording medium.

The transparent substrates 10 and 2 as described above.
By producing a magneto-optical recording medium using 0 and 30, the clock generated due to the discontinuous regions 5 and 50 when the laser light travels in the groove 3 and the laser light travels in the land 4. In this case, the clock generated due to the discontinuous regions 6 and 60 can be almost the same clock,
It is possible to record and reproduce signals on the groove 3 and the land 4 at the same timing.

Further, the address information recorded by wobble can be accurately detected.

Furthermore, the tracking error signal generated due to the discontinuous areas 5 and 50 when the laser light travels in the groove 3 and the discontinuous areas 6 and 60 when the laser light travels in the land 4 are produced. The tracking error signal generated due to can be made almost the same tracking error signal, the center of the groove 3 and the center of the land 4 can be irradiated with the same laser beam, and accurate signal recording and reproduction can be performed.

In the above description, the translucent substrates 10, 20, 30 are arranged so that the groove 3 and the land 4 have the same width.
Although the width of the groove 3 and the width of the land 4 formed in the above are not mentioned, it goes without saying that the dielectric layer 12 and the magnetic layer 13 deposited on the translucent substrate 10, 20, 30 are not described. The width of the groove 3 and the width of the land 4 formed on the translucent substrate 10, 20, 30 may be different so that the width of the groove and the width of the land at the interface with and are the same. In this case, if the width of the groove is Wg and the width of the land is Wl, then Wg-Wl = 4d / sin θ (7) holds.

As a result, the recording and reproducing characteristics of the signal in the groove and the recording and reproducing characteristics of the signal in the land can be made substantially the same.

[Brief description of drawings]

FIG. 1 is a plan view of a translucent substrate according to the present invention.

FIG. 2 is a cross-sectional view in the track direction of a discontinuous area in a magneto-optical recording medium.

3 is a sectional structural view of a magnetic layer formed on the transparent substrate of FIG.

FIG. 4 is a diagram illustrating in detail a discontinuous region formed on the transparent substrate of FIG.

FIG. 5 is a diagram illustrating the basis for determining the length in the track direction of a discontinuous region formed on the transparent substrate of FIG.

FIG. 6 is another plan structure diagram of the translucent substrate according to the present invention.

7 is a diagram illustrating in detail wobbles formed on the translucent substrate illustrated in FIG.

FIG. 8 is still another plan structure view of the translucent substrate according to the present invention.

FIG. 9 is a block diagram of a translucent substrate cutting device according to the present invention.

10 is an example of input data and carrier signals in the cutting device shown in FIG.

11 is a circuit diagram showing a specific configuration of a rectifier of the cutting device shown in FIG.

12 is a diagram for explaining the operation of the cutting device shown in FIG.

13 is a diagram for explaining the operation of the cutting device shown in FIG.

FIG. 14 is a view for explaining the operation of the cutting device shown in FIG.

FIG. 15 is a diagram for explaining the locus of laser light by the cutting device shown in FIG. 9.

16 is a view for explaining the operation of the cutting device shown in FIG.

FIG. 17 is a diagram for explaining the locus of laser light by the cutting device shown in FIG. 9.

FIG. 18 is a diagram for explaining the operation of the cutting device shown in FIG. 9.

FIG. 19 is a diagram for explaining the locus of laser light by the cutting device shown in FIG. 9.

FIG. 20 is a plan view of a conventional transparent substrate.

FIG. 21 is a diagram for explaining a conventional problem.

[Explanation of symbols]

1, 110 ... Address area 2, 120 ... Data recording area 3 ... Groove 4 ... Land 5, 6, 50, 60, 130, 140 ... Discontinuous area 10, 20, 30 , 101 ... Translucent substrate 12, 102 ... Dielectric layer 13, 103 ... Magnetic layer 7, 8, 71, 72, 81, 82, 111, 112 ...
Wobbles 73, 74, 83, 84 ... Area 90 ... Glass substrate 91 ... Motor 92 ... Motor driver 93 ... First laser 94 ... Second laser 95 ... 1st deflector 96 ... 2nd deflector 97 ... Mirror 98 ... Reflecting mirror 99 ... Objective lens 100 ... Magneto-optical recording medium 131 ... Reproducing layer 132 ... Nonmagnetic layer 133 ... Recording layer 150 ... First interface 151 ... First encoder 152 ... First carrier generator 153 ... First amplitude modulator 154 ... First amplifier 155 ... 1 rectifier 156 ... 1st offset device 157 ... 1st deflector driver 158 ... 2nd interface 159 ... 2nd encoder 160 ... 2nd carrier generator 161 ... 2nd amplitude Regulator 162 ... Second amplifier 163 ... Second rectifier 164 ... Second offset device 165 ... Second deflector driver 166 ... First laser drive circuit 167 ... Second laser drive circuit 171 ... Diodes 180, 181, 185, 186, 190, 191 ...
·Trajectory

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-11-73685 (JP, A) JP-A-7-105569 (JP, A) JP-A-10-261242 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) G11B 11/105 G11B 7/24

Claims (4)

(57) [Claims] 1. A light-transmissive substrate in which tracks composed of lands and grooves are formed spirally or concentrically, a dielectric layer formed on the lands and grooves, and a dielectric layer formed on the dielectric layer. In a magneto-optical recording medium including a magnetic layer, the land includes a first discontinuous region including grooves formed at regular intervals, and the groove includes second lands formed at regular intervals. Including a discontinuity region of the first discontinuity region,
Track direction of the first discontinuous region at a depth of 1
Is Lg, the glue forming the first discontinuous region is
Glue in the dielectric layer at a depth of approximately one half
The thickness in the direction perpendicular to the inclined portion of the groove is d, and the inclination of the groove is
The inclination angle of the slope is θ, and the land forming the second discontinuous region
Of the second discontinuity region at a height of approximately one half of
If the length in the track direction is L1, then Lg−2 × (d / sin θ) = Ll + 2 × (d / sin
A magneto-optical recording medium satisfying the relationship of θ) . 2. A light-transmissive substrate in which tracks made of lands and grooves are spirally or concentrically formed, a dielectric layer formed on the lands and grooves, and a dielectric layer formed on the dielectric layer. In a magneto-optical recording medium including a magnetic layer, the land includes a first discontinuous region including grooves formed at regular intervals, and the groove includes second lands formed at regular intervals. Including a discontinuity region of the first discontinuity region,
Track direction of the first discontinuous region at a depth of 1
Is Lg, the glue forming the first discontinuous region is
Glue in the dielectric layer at a depth of approximately one half
The thickness in the direction perpendicular to the inclined portion of the groove is d, and the inclination of the groove is
The inclination angle of the slope is θ, and the land forming the second discontinuous region
Of the second discontinuity region at a height of approximately one half of
If the length in the track direction is L1, then Lg−2 × (d / sin θ) = Ll + 2 × (d / sin
θ) is established, and the radial length of the first discontinuous region at a depth of approximately ½ of the groove forming the first discontinuous region is the second discontinuous region. A magneto-optical recording medium that is longer than the radial length of the second discontinuous region at a height of approximately one-half of the land that constitutes the region. 3. A light-transmissive substrate in which tracks made of lands and grooves are spirally or concentrically formed, a dielectric layer formed on the lands and grooves, and a dielectric layer formed on the dielectric layers. In a magneto-optical recording medium including a magnetic layer, the land includes a first discontinuous region including grooves formed at regular intervals, and the groove includes second lands formed at regular intervals. And a wobble, which is address information, on at least one of the walls, and is approximately half of the groove forming the first discontinuous area.
Track direction of the first discontinuous region at a depth of 1
Is Lg, the glue forming the first discontinuous region is
Glue in the dielectric layer at a depth of approximately one half
The thickness in the direction perpendicular to the inclined portion of the groove is d, and the inclination of the groove is
The inclination angle of the slope is θ, and the land forming the second discontinuous region
Of the second discontinuity region at a height of approximately one half of
If the length in the track direction is L1, then Lg−2 × (d / sin θ) = Ll + 2 × (d / sin
θ) holds , and the wobble has a first wavelength wobble that is convex toward the land adjacent to the wall of the groove in which the wobble is formed, and a wobble that is opposite to the wobble of the first wavelength. And a wobble of a second wavelength that is
Recording media longer than the wavelength of. 4. A translucent substrate in which tracks made of lands and grooves are formed spirally or concentrically, a dielectric layer formed on the lands and grooves, and a dielectric layer formed on the dielectric layer. In a magneto-optical recording medium including a magnetic layer, the land includes a first discontinuous region including grooves formed at regular intervals, and the groove includes second lands formed at regular intervals. And a wobble, which is address information, on at least one of the walls, and is approximately half of the groove forming the first discontinuous area.
Track direction of the first discontinuous region at a depth of 1
Is Lg, the glue forming the first discontinuous region is
Glue in the dielectric layer at a depth of approximately one half
The thickness in the direction perpendicular to the inclined portion of the groove is d, and the inclination of the groove is
The inclination angle of the slope is θ, and the land forming the second discontinuous region
Of the second discontinuity region at a height of approximately one half of
If the length in the track direction is L1, then Lg−2 × (d / sin θ) = Ll + 2 × (d / sin
θ) is established, and the radial length of the first discontinuous region at a depth of approximately ½ of the groove forming the first discontinuous region is the second discontinuous region. The wobble is longer than the radial length of the second discontinuous region at a height that is approximately one half of the land that constitutes the region, and the wobble is convex toward the land adjacent to the wall of the groove in which the wobble is formed. And a wobble of a second wavelength that is convex on the opposite side of the wobble of the first wavelength, and the first wavelength is the second wobble of the second wavelength.
Recording media longer than the wavelength of.