JP2000207748A - Management method for address of optical recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical recording medium address management method that can prevent crosstalks that mix into address information. SOLUTION: Groove G and land L are defined as recording/reproducing tracks. An address information 3 is recorded on the boundary of the adjacent recording/reproducing tracks. The recording/reproducing tracks of the adjacent groove G and land L are designated to different addresses and the recording/ reproducing tracks of the groove G and land L are designated to the address continuous to the recording/reproducing tracks of the groove G and land L.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an address management method for an optical recording medium such as a magneto-optical disk in which address information of a recording / reproducing track is recorded in advance by using a pit array of pits.

[0002]

2. Description of the Related Art Magneto-optical disks are being researched and developed as rewritable optical disks, and some magneto-optical disks have already been put into practical use as external memories for computers.

[0003] A magneto-optical disk uses a perpendicular magnetization film as a recording medium and performs recording and reproduction using light. Therefore, the magneto-optical disk is characterized by having a larger recording capacity than a floppy disk or a hard disk using an in-plane magnetization film. .

As shown in FIG. 12, on a land 52 between grooves 51 formed on a magneto-optical disk, address information of a track on which information is recorded / reproduced is recorded by an uneven pit row 53. Light spot 5
The address information of the track corresponding to the land 52 on which the scan 5 is scanning can be obtained.

The track pitch is set to be about the diameter of the light spot 55, and the diameter of the light spot 55 is determined by the wavelength of the laser light and the numerical aperture of the objective lens for condensing the laser light as the light spot 55. I have. The wavelength of the laser beam is usually 780 to 830 nm, and the numerical aperture of the objective lens is 0.45 to 0.6. Therefore, the diameter of the light spot 55 is 1.2 to 1.4 μm, and the track pitch is also set to 1.4 to 1.6 μm. Therefore, the size of the recording domain 54 whose magnetization is upward or downward is about 0.8 μm at the minimum.

In recent years, the recording density of this magneto-optical disk has been improved by increasing the number of magnetic layers of the recording film to allow reproduction of recording bits far smaller than the size of the light spot 55 by magnetic super-resolution. For example, Japanese Patent Application Laid-Open No. 5-81717 and the Journal of the Japan Society of Applied Magnetics, vol. 15, No. 5, 1991, pp. 838-
845). According to these proposals, approximately 1 /
Since a recording bit having a size of 2 can be reproduced, the track pitch can be reduced to about 0.8 μm, which is almost １ ／.

[0007] Further, as shown in FIG.
A method has also been proposed for reducing crosstalk of a recording signal, which is noise mixing from an adjacent track, in a phase-change optical disk in which recording domains 58 are formed in a recording domain 58 and a land 57, respectively (for example, the 53rd JSAP). Proceedings of the Lectures No.3, 18a-T-2, 1992 p.948 and
Improvement of track density by land and gr
oove recording onphase change optical disk;
CONFERENCE DIGEST July, 1993 pp.57-58; JOINT
INTER-NATIONAL SYMPOSIUM ON OPTICAL MEMORY
AND OPTICALDATA STORAGE).

[0008]

However, in the above-mentioned conventional configuration, for example, if the track pitch is reduced to が, the distance between the pits 53 of the adjacent track is reduced to 、. There is a problem that the crosstalk in which the address signals of 53 are mixed increases, and accurate address information cannot be obtained.

Further, when the pit row 53 for giving address information to each of the groove 56 and the land 57 is formed, there is a problem that the manufacturing process of the optical disk becomes complicated.

An object of the present invention is to provide an address management method for an optical recording medium that can prevent crosstalk in which address information is mixed.

[0011]

An address management method for an optical recording medium according to the present invention uses a groove and a land as recording / reproducing tracks, and manages the address of an optical recording medium in which address information is recorded at a boundary between adjacent recording / reproducing tracks. In the method, the recording and reproduction tracks of adjacent grooves and lands are
In addition to specifying different addresses, the recording and reproducing tracks of the groove and the land are specified as addresses that are continuous to the recording and reproducing tracks of the groove and the land, respectively.

Further, one of the recording and reproduction tracks adjacent to each other is designated at the same address as the address information, and the other is designated by converting by the formula (address by the address information) + (total number of tracks) / 2. It is characterized by the following.

Further, one of the recording and reproduction tracks adjacent to each other is designated to the same address as the address information, and the other is converted and designated by the formula of (total number of tracks)-(address by the address information) +1. It is characterized by.

Further, in the address management method for an optical recording medium having a recording / reproducing track having address information recorded on a boundary, different addresses are designated for recording / reproducing tracks adjacent to each other, and a continuous address is assigned to the recording / reproducing track 1. It is characterized in that it is specified every other book.

According to the address management method for an optical recording medium of the present invention as described above, the access speed can be increased.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS.

The magneto-optical disk used in this embodiment includes:
As shown in FIG. 1, a groove 1 and a land 2 between the grooves 1 are formed in a spiral shape or concentric shape. Since information is recorded as the recording bit string 4 in each of the groove 1 and the land 2, one round of each of the groove 1 and the land 2 becomes a track for recording and reproduction. Further, the width of the groove 1 and the width of the land 2 are set so that the reproduction signal quality of the recording bit string 4 recorded on the groove 1 and the reproduction signal quality of the recording bit string 4 recorded on the land 2 are almost the same. They are set to be substantially equal to each other.

At the boundary between the adjacent groove 1 and land 2, an uneven pit row 3 described later in detail is formed, and the pit row 3 is formed at every other boundary. Address information indicating the address of each recording / reproducing track on the magneto-optical disk is recorded by this pit string 3.

For convenience of explanation, as shown in FIG. 1, each groove 1 is sequentially given a sub-sign [G1, G2, G3], and each land 2 and each pit row 3 are also sequentially assigned [L1 , L2, L3] and [P1, P2, P3], and when it is necessary to identify each groove 1 in the following description, the sub-symbol will be used. The same applies to the land 2 and the pit row 3.

Here, the adjacent groove 1 and land 2 are considered as one set. That is, the adjacent groove G1
And the land L1, the adjacent groove G2 and the land L2, and the adjacent groove G3 and the land L3 are considered as one set.

As is apparent from FIG. 1, a series of pit rows 3 is formed for each pair of the groove 1 and the land 2. That is, the pit row P1 is formed on the boundary between the groove G1 and the land L1, the pit row P2 is formed on the boundary between the groove G2 and the land L2, and the pit row P3 is formed on the boundary between the groove G3 and the land L3. . Therefore,
In other words, the pit rows 3 are formed at every other boundary on the boundary between the adjacent groove 1 and land 2.

In this case, the groove G1 and the land L1
Is recorded by the pit train P1, the same address is given to the groove G1 and the land L1. Similarly, the groove G2 and the land L2
, The same address is given by the pit row P2,
The same address is given to the groove G3 and the land L3 by the pit row P3.

FIG. 10A is a cross-sectional view of the substrate 7 having a pit row 3 formed at the boundary between the groove 1 and the land 2 as seen from the direction of arrows AA. In FIG. 10A, the pit row 3 is
By drilling one corner of the top surface of the land 2 and further drilling one corner of the bottom surface of the groove 1,
It can be seen that they are formed at the boundary between the land 2 and the land 2.

In the above configuration, the recording bit string 4 is formed by using the high power light spot 5 to record information on the magneto-optical disk, and by scanning the recording bit string 4 with the low power light spot 5. When information is reproduced from the magneto-optical disk, tracking control for the groove 1 or tracking control for the land 2 is performed.

As an example, as shown in FIG. 1, when the light spot 5 scans the recording / reproducing track of the groove G2, the address information is obtained from the pit row P2 formed on the boundary between the groove G2 and the land L2. can get. At this time, in this embodiment, the adjacent groove 1 and land 2
The pit rows 3 are arranged every other on the boundary of, so that the interval between adjacent pit rows 3 is twice the track pitch. To further explain the relationship between the irradiation center of the light spot 5 and the pit row 3, the distance between the center of the groove G2 coincident with the irradiation center of the light spot 5 and the adjacent pit row P1 is 1.5 times the track pitch. The distance between the center of the groove G2 and the pit row P3 on the opposite side is 2.5 times the track pitch.

As a result, since the radius of the light spot 5 is smaller than the track pitch, when the light spot 5 scans, for example, the pit row P2, the adjacent pit row P1 or pit row P3 illuminates the irradiation area of the light spot 5. Will have a considerable distance from Therefore, compared with the case where a pit row is formed in each of the groove and the land, crosstalk from an adjacent pit row is extremely small, and accurate address information can be obtained.

Similarly, even when the light spot 5 scans the track of the land L2, accurate address information can be obtained from the same pit row P2.

At this time, the discrimination between the recording / reproducing track of the groove G2 and the recording / reproducing track of the land L2 is made by the tracking signal between when the light spot 5 irradiates the groove 1 and when the light spot 5 irradiates the land 2. , The polarity can be easily detected by detecting the polarity. The tracking signal can be obtained by, for example, a push-pull method. Further, the detection of the polarity of the tracking signal is performed, for example, in order to count the number of times the light spot crosses the track at the time of a track jump,
What is necessary is just to apply the structure which compares a tracking signal with a threshold value.

Therefore, the groove G2 or the land L
In the recording / reproducing using the recording / reproducing track 2 as the recording / reproducing track, even if the same address information is obtained from the same pit row P2, which recording / reproducing track of the groove G2 or the land L2 is being recorded or reproduced by taking the polarity of the tracking signal into consideration. Can be easily specified.

As another method for discriminating between the groove 1 and the land 2, as shown in FIG. 2, a discriminating pit 11 is previously formed on one of the groove 1 and the land 2. Alternatively, the determination can be made by using a reproduction signal from the determination pit 11. The pit 11 for discrimination
May be formed before or after the pit row 3. As shown in FIG. 2, when the pits 11 for discrimination are formed on each land 2, when the refractive index of the substrate is n, the track pitch is T, and the wavelength of the light spot 5 is λ, the depth is about λ / 4n, 0.3 width
It is preferable to form a discrimination pit 11 of T to 0.4T. This is because, in this case, the reproduction signal of the discrimination pit 11 is maximized, and the crosstalk from the adjacent discrimination pit 11 is suppressed to be small.

When the light spot 5 is scanning over the land 2, the reproduced signal intensity is different from the signal intensity obtained from the pit row 3 and can be clearly distinguished. On the other hand, when the light spot 5 is scanning over the groove 1, the signal obtained from the discrimination pit 11 is much smaller than when scanning over the land 2. Therefore, the groove 1 and the land 2 can be distinguished from each other by the change in the signal intensity obtained from the distinction pit 11.

In this embodiment, the pit row 3 is formed, for example, at the boundary between the groove G2 and the land L2, and when the light spot 5 scans the groove G2, the pit row 3 moves in the moving direction of the light spot 5. Although the case where the pit row 3 is arranged on the right side is shown, it is also possible to form the pit row 3 on the boundary between the groove G2 and the land L1 and arrange the pit row 3 on the left side in the moving direction of the light spot 5. There is no difference in the signal amount obtained from the pit row 3 in either case.
Alternatively, the relative position between the land 2 and the pit row 3 needs to be limited.

Next, an address management method according to the present invention will be described.

First, in the first method, which is a reference example on which the present invention is based, as shown in FIG. 8A, both the groove and the land where the pit row 3 is formed at the boundary have the same address. Is managed by In this case, since the address read from the pit row 3 is used as it is, the pit row 3
There is a merit that the management of the address becomes easier as compared with the method of converting the address read from the address into the address of the groove or the land.

Next, in a second method which is a reference example on which the present invention is based, as shown in FIG.
Each pit row 3 is formed so as to increase in increments. Then, one of the groove and the land is designated to the same address as the address of the pit string 3, and the other is converted and designated by adding 1 to the address of the pit string 3. Thus, the groove and the land where the pit row 3 is formed at the boundary are managed by different addresses. In this case, the addresses are continuous in the radial direction of the optical disc,
There is a merit that the recording / reproducing track of the target address can be easily accessed.

In the third method, which is the method of the present invention, as shown in FIG. 8C, each pit row 3 is formed so that the address is incremented by one, as in the first method. deep. Then, one of the groove and the land is placed in the pit row 3
And the other address is converted and specified by the formula of (address by pit string) + (total number of tracks) / 2. Thus, the groove and the land where the pit row 3 is formed at the boundary are managed by different addresses. In this case, since the address is continuous in each of the groove and the land, the servo switching between the groove and the land becomes unnecessary when searching for a continuous address and accessing the target recording / reproducing track. There is an advantage that the speed can be increased.

Further, in a fourth method which is another method of the present invention, as shown in FIG. 8D, each pit row 3 is formed so that the address is increased by one similarly to the first method. Keep it. Then, one of the groove and the land is specified at the same address as the address of the pit row 3, and the other is converted and specified by the expression (total number of tracks) − (address by pit row) +1. Thus, the groove and the land where the pit row 3 is formed at the boundary are managed by different addresses. In this case, when accessing a target recording / reproducing track by searching for a continuous address, servo switching between the groove and the land becomes unnecessary. further,
In the last address of the pit string, (total number of tracks) / 2 and (total number of tracks) / 2 + 1 are the addresses of the adjacent groove and land. Since it is sufficient to search for the address of the target track, the access speed can be further increased.

Next, the pit shape of the pit row 3 suitable for the optical recording medium used in the present invention will be described below.

FIGS. 3 to 5 show the width of the groove 1 and the land 3.
Are 0.8 μm each (that is, the track pitch is 0.8 μm).
9 is a graph showing the result of obtaining the relationship between the diffraction intensity of the pit row 3 and the pit shape of the pit row 3 when the light spot 5 scans the land 2 when the light spot 5 scans the land 2.

Here, as a condition, the substrate has a refractive index n of 1.
The groove is 55n deep using 58 polycarbonate.
m. The wavelength λ of the reproduction light is 780 nm, and the numerical aperture NA of the focusing objective lens is 0.55. Note that the signal intensity was obtained as a ratio to the reflection intensity at the flat portion of the substrate.

FIG. 3 shows a change in the pit signal intensity with respect to a change in the pit width when the pit length of the pit row 3 is fixed. The pit length was 2.4 μm (long pit) and 0.7 to 0.8 μm (short pit), and the pit depth was 130 nm. Short pit row is 1.52μm
, The signal intensity is slightly affected by the adjacent short pits, and the signal intensity is reduced by only one short pit.
It is smaller than the case of irradiation.

FIG. 4 shows the result of determining the relationship between the pit width and the intensity of the crosstalk signal mixed in from the adjacent pit row 3 when the pit length is 2.4 μm and the pit depth is 130 nm.

From the results of FIGS. 3 and 4, according to the present invention,
When the pit width is in the range of about 0.3 to 0.7 μm, the pit signal intensity exceeds about 0.2, and the crosstalk from the adjacent pit row 3 is also almost 0, so that a sufficient address signal can be obtained. Can be.

FIG. 5 shows that each pit width of the pit row 3 is 0.5 μm.
When m is set, the change in the pit signal intensity with respect to the change in the pit depth is obtained. The pit length is shown in FIG.
2.4 μm (long pit) and 0.7 to
Two short pitches of 0.8 μm (short pits) were formed, and short pit rows were formed at a period of 1.52 μm. The result of the long pit is indicated by a solid line, and the result of the short pit is indicated by a broken line.

From the results shown in FIG. 5, in the present invention, when the pit depth is in the range of about 100 to 160 nm, the pit signal intensity exceeds about 0.2, and a sufficient address signal can be obtained.

Also, when the light spot 5 scans on the groove 1, the same result as in the case of scanning on the land 2 as described above can be obtained.

Here, for comparison, FIG. 4 and FIG.
FIG. 7 shows the results of forming a pit row in each of a groove and a land having a width of 0.8 μm, and determining the relationship between the diffraction intensity of the pit row and the pit shape of the pit row. As shown in FIG. 4 and FIG.
The conditions in each case are the same between the present invention and the comparative example.

From the results shown in FIGS. 4 and 11, in the conventional example, the pit signal intensity is large, but as the pit width increases, the amount of croxtalk from the adjacent pit row increases, so that it is impossible to obtain an accurate address signal. Have difficulty. Also, from the results shown in FIG. 11, it can be seen that the pit width dependency is large in the conventional example, especially in the pit signal intensity of the long pit. As a result, in the conventional example, if the pit row is not formed in an accurate shape, erroneous detection of the address signal occurs,
The crosstalk amount is likely to increase.

Also in this regard, as is apparent from the results of FIGS. 3 and 4, according to the present invention, the pit width of the pit row 3 is small because the pit signal intensity and the crosstalk amount are less dependent on the pit width. There is an advantage that the required accuracy is eased and the formation of the pit row 3 is facilitated.

The degree to which the pit signal intensity depends on the pit width is related to the degree of light diffraction by the pits. In the conventional example, a pit row is formed at the center of a groove or a land, and each pit is irradiated at the center of a light spot, so that the degree of light diffraction by the pits is increased. On the other hand, according to the present invention, the pit train 3 is adjacent to the groove 1.
Pit row 3
Is applied at the outer periphery of the light spot 5 that irradiates the center of the groove 1. When the pit row 3 is irradiated on the outer periphery of the light spot 5, the diffraction intensity of the light becomes small.
The pit signal intensity must be smaller than the conventional example, but the pit width dependency can be reduced instead.

Next, when the track pitch is changed, the relationship between the diffraction intensity of the pit row 3 when the light spot 5 scans the land 2 and the pit shape of the pit row 3 is shown in Table 1. And Table 2. For comparison,
Tables 1 and 2 also show the results of the conventional example in which a pit row was formed in each of a groove and a land having a width of 0.8 μm.

In Table 1, the substrate is polycarbonate having a refractive index n of 1.58, the groove depth is 55 nm, the wavelength λ of the reproduction light is 780 nm, the numerical aperture NA of the objective lens for focusing is 0.55, and the pits are The depth is 130 nm.

On the other hand, in Table 2, except that the wavelength λ of the reproduction light was changed to 680 nm and the light beam radius r ₀ (1 / e ^{2 of the} center intensity) was changed from 0.60 in Table 1 to 0.55. Is the same as

[0054]

[Table 1]

In Table 1 above, in each of the present invention and the conventional example, the pit width at which the long pit signal is maximum for each track pitch is selected, and the value of the crosstalk signal mixed from the adjacent long pit row at that time is selected. Is underlined. FIG. 6 is a graph obtained by plotting the underlined values against the track pitch.

[0056]

[Table 2]

In Table 2 above, in each of the present invention and the conventional example, the pit width at which the long pit signal is maximum for each track pitch is selected, and the value of the crosstalk signal mixed from the adjacent long pit row at that time is selected. Is underlined. FIG. 7 is a graph obtained by plotting the underlined values against the track pitch.

As is apparent from the values of the long pit signal and the short pit signal in Tables 1 and 2, according to the present invention, even if the track pitch is 0.4 μm, a sufficient signal intensity exceeding 0.2 is obtained. can get. Table 1 and FIG.
From the results, it can be said that when the wavelength λ is 780 nm, up to a track pitch of about 0.6 μm, the crosstalk signal intensity from the adjacent pit row is sufficiently small, and a good pit signal can be obtained. Furthermore, from the results in Table 2 and FIG.
When the wavelength λ is 680 nm, the track pitch is 0.5
Up to about μm, it can be said that the crosstalk signal intensity from the adjacent pit row is sufficiently small and a good pit signal can be obtained.

On the other hand, in the conventional example, when the track pitch is reduced, the intensity of the crosstalk signal from the adjacent pit row sharply increases, making it difficult to obtain an accurate pit signal.

In the above description, a pit shape suitable for the case where the wavelength λ is 780 nm and 680 nm, the numerical aperture NA of the objective lens is 0.55, and the refractive index n of the substrate is 1.58 has been described. If the track pitch is T
(In the present invention, the pit width is Pw, the pit depth is Pd, the wavelength is λ,
Assuming that the refractive index of the substrate is n, the track pitch T can be reduced to T ≧ 0.35 × λ / NA, and the pit width Pw
If 0.4T ≦ Pw ≦ 1.2T, a sufficiently good pit signal can be obtained.

Further, when T ≧ 0.35 × λ / NA and 0.5T ≦ Pw ≦ 1.0T, a higher quality pit signal can be obtained, which is preferable. The pit depth is λ / 6n ≦ Pd ≦ λ /
A sufficiently good pit signal can be obtained in the range of 3n.

As a magneto-optical recording medium, for example, Japanese Unexamined Patent Publication No.
When a magnetic super-resolution recording medium as disclosed in Japanese Patent No. 81717 is used, the size of the recording bit 4 can be reduced to about 0.4 μm, and in addition, the recording bit can be reproduced from an adjacent track when reproducing the recording bit. The present invention is particularly suitable because recording and reproduction can be easily performed even when the track width (the width of each of the grooves 1 and the lands 2 in this embodiment) is 0.8 μm or less.

If the above magnetic super-resolution recording medium is applied to this embodiment, the track pitch can be reduced to 0.8 μm or less, so that the recording density can be greatly improved. Moreover, according to the present invention, accurate address information can be obtained.

If the wavelength of the laser beam used for recording / reproduction is reduced, the track pitch can be further reduced. For example, the wavelength of the laser light is changed from 830 nm to 458
When the length is reduced to nm, the track pitch can be further reduced to about 1/2, and the recording density can be further increased.

Next, the mastering process of the magneto-optical disk shown in this embodiment will be described with reference to FIGS. 9A to 9F.

First, as shown in FIG. 9A, a photoresist 8 is applied to one surface of a substrate 7 made of quartz glass. Next, a laser beam is focused on the photoresist 8 and the photoresist 8 is exposed in a desired pattern of the groove 1 and the pit row 3. At this time, the pit train 3
The power of the laser beam when forming the pattern is increased. When this is developed to remove the unnecessary photoresist 8, as shown in FIG. 9B, the photoresist 8 having the pattern of the groove portion 8b and the pit portion 8a corresponding to the groove 1 and the pit row 3 is formed on the substrate 7. Remain on top.

Next, as shown in FIG.
The substrate 7 is dry-etched using the dist 8 as a mask.
You. As a specific method of dry etching, for example,
CF _FourHalogen gas such as
Reactive ion etching is suitable. etching
Thereafter, when the photoresist 8 is removed, as shown in FIG.
As described above, on the substrate 7, the groups corresponding to the groove portions 8b are provided.
The pit pattern corresponds to the pit portion 8a.
A pattern 7a is formed and an adjacent groove pattern 7b
A land pattern 7c is formed between them.

Subsequently, as shown in FIG. 9E, a metal layer 9 made of Ni is formed by electroforming. When this is peeled off, a stamper made of the metal layer 9 having the projection 9a is obtained as shown in FIG. 9 (f). By molding a plastic such as polycarbonate using the stamper, a substrate for a magneto-optical disk having desired grooves 1 and pit rows 3 is manufactured. When a recording medium layer is provided on this substrate, the magneto-optical disk of this embodiment can be obtained.

Further, after exposing the photoresist 8 to a desired pattern of the groove 1 and the pit row 3 by a laser beam, a photomask is manufactured as disclosed in, for example, Japanese Patent Publication No. 4-2939. The magneto-optical disk may be manufactured by directly forming the grooves 1 and the pit rows 3 on the glass substrate by a contact exposure method using a mask and a dry etching method.

In any case, the formation of the groove 1 and the pit row 3 starts when the photoresist 8 is exposed by, for example, an argon laser beam. A device for exposing a photoresist by argon laser light is usually called a cutting device. A method of forming both the groove 1 and the pit row 3 with one argon laser light beam is formed by one beam cutting method and two beams. The method is called a two-beam method.

When the pit row 3 is formed at the boundary between the groove 1 and the land 2 as in this embodiment, for example, a three-beam method may be used. In this case, the groove 1 may be formed by two beams, and the pit row 3 may be formed by the remaining one beam.
In the three-beam method, the groove width can be controlled by changing the interval between the two beams, and the groove depth and pit depth can be controlled by changing the intensity of each beam.

In the above description, the pit depth of the pit row 3 is made constant, but it is not always necessary to make it constant. For example, as shown in FIG. 10B, the depth of the pit row 3 may be different between a part belonging to the groove 1 and a part belonging to the land 2, and a step may be provided at the bottom of the pit row 3. In this case, the limited range of the pit width and the pit depth of the pit row 3 has the merit of being wider than the limited range of the above-described embodiment, and the accuracy of the pit depth is relaxed to form the pit row 3. There is also a merit that manufacturing of the magneto-optical disk becomes easy.

Further, as shown in FIG. 10C, the pit depth of the pit row 3 and the depth of the groove 1 may be the same. In this case, there is no need to change the depths of the pit row 3 and the groove 1, and therefore, there is an advantage that the manufacturing becomes easier as compared with the above embodiment.

In the above embodiments, a magneto-optical disk has been described. However, the present invention can be widely applied to an optical disk in which address information is recorded by uneven pits, for example, a phase-change optical disk. Further, the present invention can be applied to a write-once (write-once) disc if a crosstalk canceling technique for a recording signal is developed in the future. Further, the present invention can be applied not only to a disk-shaped optical recording medium but also to, for example, a card-shaped optical recording medium.

[0075]

According to the address management method for an optical recording medium of the present invention, the access speed can be increased.

[Brief description of the drawings]

FIG. 1 is a plan view schematically showing a configuration of a magneto-optical disk used in the present invention having a pit row for giving address information.

FIG. 2 is a plan view schematically showing a configuration of a magneto-optical disk having a discrimination pit and a pit row used in the present invention.

FIG. 3 is a graph showing a change in pit signal intensity with respect to a pit width obtained from the pit train shown in FIG. 1;

FIG. 4 is a graph showing a change in crosstalk signal intensity with respect to a pit width in an optical recording medium used in the present invention and a conventional example.

FIG. 5 is a graph showing a change in pit signal intensity with respect to a pit depth obtained from the configuration of the pit row shown in FIG. 1;

FIG. 6 is a graph showing a change in crosstalk signal strength with respect to a track pitch between an optical recording medium used in the present invention and a conventional example.

FIG. 7 is a graph showing a change in crosstalk signal intensity with respect to a track pitch when the result of FIG. 6 is obtained and when the wavelength of light is changed, comparing the optical recording medium used in the present invention with a conventional example. is there.

FIG. 8 is an explanatory diagram showing an address management method of the present invention.

FIGS. 9A to 9F are schematic longitudinal sectional views sequentially showing the steps of manufacturing a magneto-optical disk having the configuration shown in FIG.

FIGS. 10A to 10C are schematic longitudinal sectional views each showing a possible shape of the pit row shown in FIG. 1;

FIG. 11 is a graph showing a change in a pit signal intensity with respect to a pit width obtained from a pit row giving address information in a magneto-optical disk having a conventional configuration.

FIG. 12 is a plan view schematically showing a configuration of a conventional magneto-optical disk having a pit row.

FIG. 13 is a perspective view schematically showing a configuration of a conventional phase change disk.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Groove 2 Land 3 Pit row 4 Recording bit string 5 Light spot 11 Discrimination pit (mark part)

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Akira Takahashi 22-22, Nagaikecho, Abeno-ku, Osaka City, Osaka Inside Sharp Corporation (72) Inventor Kenji O22-22, Nagaikecho, Abeno-ku, Osaka City, Osaka (72) Inventor Shigeo Terashima 22-22 Nagaikecho, Abeno-ku, Osaka City, Osaka Sharp Corporation

Claims (4)

[Claims] 1. An address management method for an optical recording medium in which a groove and a land are used as recording / reproducing tracks and address information is recorded at a boundary between adjacent recording / reproducing tracks. And a recording / reproducing track of the groove and the land is designated as an address continuous to the recording / reproducing track of the groove and the land, respectively. 2. The address management method for an optical recording medium according to claim 1, wherein one of adjacent recording / reproducing tracks is designated to the same address as the address information, and the other is (address according to the address information) + An address management method characterized by conversion and designation by an expression of (total number of tracks) / 2. 3. The address management method for an optical recording medium according to claim 1, wherein one of recording and reproduction tracks adjacent to each other is designated to the same address as the address information, and the other is (total number of tracks)-(the total number of tracks). An address management method characterized by conversion and designation by an expression of (address based on address information) +1. 4. An address management method for an optical recording medium having a recording / reproducing track in which address information is recorded at a boundary, wherein different addresses are designated for recording / reproducing tracks adjacent to each other, and a continuous address is assigned to the recording / reproducing track 1. An address management method for an optical recording medium, which is designated every other book.