JP2002157789A - Optical information medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the error rate of a data signal low by eliminating a reading error caused by the difference of an optical condition due to the existence of a land pre-pit showing address information in optically reading a recorded signal. SOLUTION: The shape of a groove-shaped tracking guide 3 is made to be different from the other part in a part adjacent to the land pre-pit 6 provided on a land 8 showing the address information. Concretely, the depth or width of the tracking guide 3 of the part adjacent to the land pre-pit 6 is changed. Thus, the difference of the optical condition due to the existence of the land pre-pit 6 is adjusted and modified. The land pre-pit 6 is also offset from the center of the land 8 to the inner peripheral side of a light-transmitting substrate 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical information medium on which optically reproducible information can be recorded.
The present invention relates to a high-density recording medium recorded and reproduced by a short-wavelength red laser beam of 70 nm, which has land prepits indicating address information and the like on lands between groove-like tracking guides of a light-transmitting substrate. .

[0002]

2. Description of the Related Art With the recent development and commercialization of short wavelength lasers, DVDs (Digi
With the standardization of the tal versatile disc standard, its practical use is progressing. In this DVD, a data recording area is set on at least one main surface, pits serving as information recording means are formed in the data recording area, and a reflective layer made of a metal film is formed thereon.

[0003] In the DVD, a different standard is defined for higher density as compared with a CD (Compact Disc) which is a standard of an optical information medium at present. For example,
In an optical pickup, a wavelength of 630 nm to 670
The use of a short wavelength red laser of nm
A is to use a high aperture ratio objective lens of 0.6.

In order to cope with the warpage of the disk, a disk having a thickness of 0.6 mm, which is about half the thickness of a CD, has been adopted. However, disk thickness 1.2mm
In order to ensure the dimensional compatibility with the CD, two discs are bonded together. According to the DVD standard, 1
It is standardized that a maximum recording capacity of about 4.7 GB is recorded on a single disc as a standard, and an average of about 133 minutes of video and audio are recorded.

Heretofore, in a recordable CD such as a CD-R, the wobble of a spiral groove-shaped tracking guide is FM-modulated to obtain address information called ATIP (Absolute Time In Pregroove). In contrast, DVD
In a recordable DVD such as -R, address information such as position information on an optical information medium is obtained by land prepits provided in advance in a land portion between a tracking guide and wobbles, instead of ATIP.

[0006]

The land pre-pits used in the DVD, which is a high-density recording medium as described above, are read together with the pits of a recording signal by an optical pickup. At this time, since the optical pickup is subjected to tracking servo along the tracking guide, it should be read by discriminating between land pre-pits and pits recording data signals formed on the grooves.

However, the portion where the land pre-pit exists has optical conditions partially different from those of the other portions. Therefore, an RF signal obtained from a pit in which data content is recorded in the portion where the land pre-pit exists, that is, the original portion, Changes will appear in the signal. More specifically, in an unrecorded state, the reflectance at the portion where the land pre-pits exist is lower or higher than that at other portions, indicating a state similar to a defect (defect). Sometimes. In the recording state, the presence of the land pre-pit causes a phenomenon that the reproduced signal becomes longer or shorter than the actual signal of the recorded pit. This phenomenon causes an error in reading the data signal.

Since a considerable number of land prepits exist on the recording surface of an optical information medium, an error occurs with a considerable probability when the above-mentioned phenomena occur. In particular, since the land pre-pit exists on the land between the tracking guides, the spot of the reproduction light passes through the tracking guide on the inner side of the land pre-pit and passes through the tracking guide on the outer side of the land pre-pit. There are times when two errors can occur, and the probability of errors caused by land pre-pits is quite high.

In view of the above-mentioned problems associated with the existence of land pre-pits for reading address information of an optical information medium compatible with high-density recording, the present invention aims at optically recording recorded signals. An object of the present invention is to provide an optical information medium capable of eliminating a reading error caused by a difference in optical conditions due to the presence of a land prepit indicating address information and suppressing a data signal error rate. .

[0010]

In order to achieve the above object, according to the present invention, a groove-shaped tracking guide 3 is formed at a portion adjacent to a land prepit 6 provided on a land 8 indicating address information. It is different from other parts. Specifically, the depth or width of the tracking guide 3 in the portion adjacent to the land pre-pit 6 is changed. Thereby, the difference in the optical conditions due to the presence of the land pre-pits 6 is adjusted and corrected.

An optical information medium according to the present invention has a light-transmitting substrate 1 through which recording light is transmitted, a recording layer 12 formed on the light-transmitting substrate 1, and a recording layer 12 formed on the recording layer 12 for reproduction. A light-reflecting layer 13 for recording an optically readable signal with the recording light incident from the light-transmitting substrate 1, wherein the recording layer 12 of the light-transmitting substrate 1 is provided. Is formed on the surface side on which is formed a spiral groove-shaped tracking guide 3. Land pre-pits 6 indicating address information are formed on lands 8 between the tracking guides 3, and light is transmitted from the land pre-pits 6. The shape of a portion of the tracking guide 3 on the inner peripheral side of the conductive substrate 1 adjacent to the land pre-pit 6 is different from other portions of the tracking guide 3.

More specifically, the depth of a portion of the tracking guide 3 located on the inner peripheral side of the translucent substrate 1 from the land prepit 6 and adjacent to the land prepit 6 is different from other portions of the tracking guide 3. Is what it is. Even more specifically, the light transmitting substrate 1
The depth of the portion of the tracking guide 3 on the inner peripheral side adjacent to the land pre-pit 6 is
Shallower than the other parts of.

Further, not only the depth of the portion of the tracking guide 3 adjacent to the land prepit 6 but also the width of the portion of the tracking guide 3 adjacent to the land prepit 6 may be changed. Specifically, the width of a portion of the tracking guide 3 on the inner peripheral side of the translucent substrate 1 from the land prepit 6 and adjacent to the land prepit 6 is made narrower than other portions of the tracking guide 3. is there.

As described above, the depth and width of the land pre-pit 6 of the tracking guide 3 and the portion adjacent to the inner peripheral side of the translucent substrate 1 are changed. Specifically, the depth is reduced or the width is reduced. Makes the optical conditions of this portion different from those of the other portions of the tracking guide 3. As mentioned above, tracking guide 3 originally
Although the portion adjacent to the land pre-pit 6 has optical conditions different from the other portions of the tracking guide 3, the depth of the portion adjacent to the land pre-pit 6 of the tracking guide 3 may be reduced as described above. By narrowing the width and appropriately setting the optical condition of the portion, the difference in the optical condition due to the presence of the land prepit 6 can be eliminated.

The land pre-pit 6 is recorded so that the spot of the read laser beam can be read normally when passing through the tracking guide 3 on the inner peripheral side of the land pre-pit 6. Therefore, land pre-pit 6
Can be read only when the spot of the reading laser beam passes through the tracking guide 3 on the inner peripheral side.
Rather, when the spot of the read laser beam passes through the tracking guide 3 outside the land pre-pit 6, if the land pre-pit 6 is read, there is only a danger of occurrence of an error.

Therefore, the land pre-pit 6 is offset from the center of the land 8 to the inner peripheral side of the light-transmitting substrate 1. Thus, when the spot of the read laser beam passes through the tracking guide 3 outside the land pre-pit 6, the influence of the land pre-pit 6 is reduced, and the spot of the read laser beam is more inward than the land pre-pit 6. When passing through the tracking guide 3 on the side, the signal of the land pre-pit 6 can be reliably read.
In particular, when the depth of the tracking guide 3 adjacent to the land pre-pit 6 is reduced or reduced, the offset amount of the land pre-pit 6 can be increased, which is effective.

[0017]

Embodiments of the present invention will now be described specifically and in detail with reference to the drawings. As an example of the optical information medium according to the present invention, an example of a write-once optical information medium having a single-sided recording / reproducing structure by double-sided bonding is shown in FIGS. The translucent substrate 1 is a transparent disk-shaped substrate having a center hole 9 at the center. The translucent substrate 1 is generally made by injection molding a transparent resin such as polycarbonate and polymethyl methacrylate (PMMA).

A clamping area is set outside the center hole 4 on one side of the translucent substrate 1 having translucency, and the outer peripheral side of the clamping area is a data recording area. A tracking guide 3 formed of a spiral groove is formed in the data recording area of the translucent substrate 1. This tracking guide 3
Is set to 0.74 μm as a standard.

As shown in FIG. 3, in the land 8 between the tracking guides 3, when recording a signal on an optical information medium, a land-shaped land pre-pit 6 for indicating address information or the like is provided at an appropriate interval. It is formed with. The land pre-pits 6 are formed in advance together with the tracking guide 3 at the time of injection molding of the translucent substrate 1.

FIGS. 4 to 6 show details of an example of the portion having the land pre-pits 6 of the light-transmitting substrate 1. As shown in these figures, in the example of the light-transmitting substrate 1, a raised portion 7 is provided in a part of the tracking guide 3, and the position thereof is located between the land pre-pit 6 and the inner periphery of the light-transmitting substrate 1. It is a portion adjacent to the side (left side in the figure). As shown in FIG. 5, the height of the raised portion 7 is the same as the height of the land 8. In other words, the depth of the tracking guide 3 at that portion becomes flush with the surface of the land 8 by the raised portion 7,
Its depth is zero. The portion of the tracking guide 3 not adjacent to the land pre-pit 6 is as shown in FIG.
That is, the portion of the raised portion 7 on the inner peripheral side adjacent to the land prepit 6 has no groove and is shallower than other portions of the tracking guide 3.

Further, in the example shown in FIGS. 7 and 8, the protruding portion 7 is provided in a portion adjacent to the land pre-pit 6 of the tracking guide 3 and the inner peripheral side of the translucent substrate 1 as described above. In addition to the above, the tracking guide 3 is offset from the center of the land 8 to the inner peripheral side of the translucent substrate 1, that is, to the raised portion 7 side of the tracking guide 3.

By offsetting the land pre-pit 6 inside the translucent substrate 1 in this manner, when the spot of the read laser beam passes through the tracking guide 3 outside the land pre-pit 6, the land pre-pit 6 6 can be reduced. Moreover, when the spot of the read laser beam passes through the tracking guide 3 inside the land pre-pit 6, the signal of the land pre-pit 6 can be read reliably.

FIGS. 9 and 10 show details of another example of the portion of the translucent substrate 1 having the land prepits 6. FIG. As shown in these figures, in the example of the light-transmitting substrate 1, a protrusion 7 is formed in a portion adjacent to the land prepit 6 of the tracking guide 3 and the inner peripheral side of the light-transmitting substrate 1. Is the same as in the previous example. However, the height of the raised portion 7 in this example is, as shown in FIG.
Is about 部分 of the depth of the other part. In other words, the depth of the tracking guide 3 in the inner portion adjacent to the land prepit 6 due to the raised portion 7 is about の of the other portion of the tracking guide 3.

In the above three examples, the land pre-pits 6 are present by reducing the depth of the land pre-pits 6 of the tracking guide 3 and the portion adjacent to the inner peripheral side of the translucent substrate 1. This is to correct that the optical conditions are different from those of the other parts of the tracking guide 3. Therefore, the height of the raised portion 7, that is, the depth of the tracking guide 3 at that portion is set so as to eliminate the difference in the optical conditions between the portion where the land prepit 6 of the tracking guide 3 is adjacent and the other portion. .

FIGS. 11 and 12 show details of another example of the portion of the light-transmitting substrate 1 having the land pre-pits 6. FIG. As shown in these drawings, in the example of the light-transmitting substrate 1, the land pre-pit 6 of the tracking guide 3 and both sides of the portion adjacent to the inner peripheral side of the light-transmitting substrate 1 are located on the center side of the tracking guide 3. A protruding portion 9 protruding toward is provided. Therefore, the width of that part of the tracking guide 3 is narrower than other parts of the tracking guide 3.

The examples shown in FIGS. 13 and 14 correspond to the land pre-pit 6 of the tracking guide 3 as described above.
In addition to providing a projection 9 at a portion adjacent to the inner peripheral side of the light-transmitting substrate 1 and narrowing the portion, the tracking guide 3 is provided inside the light-transmitting substrate 1, that is, the tracking guide 3.
It is offset to the side.

As in these examples, the portion adjacent to the land prepit 6 of the tracking guide 3 and the inner peripheral side of the light-transmitting substrate 1 is made narrower than the other portions of the tracking guide 3 to achieve the above-described operation. In the same manner as in the example, the optical conditions are different from those of the other parts of the tracking guide 3 due to the presence of the land pre-pits 6.

The land pre-pit 6 of the tracking guide 3 and the portion adjacent to the inner peripheral side of the light-transmitting substrate 1 are made narrower than other portions of the tracking guide 3, and Making adjacent portions shallower than other portions may be used together.

After preparing such a light-transmitting substrate 1, as shown in FIGS. 1 to 3, a recording layer 1 is formed on the main surface of the light-transmitting substrate 1.
2 are formed. For example, an organic dye or the like is applied by a method such as a spin coating method, and the recording layer 12 is formed. Further, on the recording layer 12, a reflective layer 13 made of a metal film of gold, aluminum, silver, copper, palladium, or the like, an alloy film thereof, or an alloy film in which a trace component is added to these metals is formed. Further, a protective film 14 such as an ultraviolet curable resin is formed on the reflective layer 13.

In addition to the light-transmitting substrate 1, another substrate 5
Prepare The substrate 5 is of the same size and made of the same material as the translucent substrate 1, but has a main surface
The tracking guide 3, the recording layer 12, and the reflection layer 13 as in the translucent substrate 1 are not provided. Needless to say, the recording layer 12 and the reflective layer 1 are formed on the substrate 5 having the tracking guide 3 similarly to the translucent substrate 1.
3 and the like can also be provided.

Next, these two substrates 1 and 5 are bonded together. For example, a reactive curable resin is applied as an adhesive to at least one main surface of the two substrates 1 and 5 by means of a spin coating method, a screen printing method, or the like, and these surfaces are superimposed on each other. And the reactive curable resin is cured. Thereby, the adhesive layer 1 formed by curing the reactive cured resin is formed.
1, the main surfaces of the two substrates 1 and 5 are bonded to each other. In this case, the light-transmitting substrate 1 is bonded with the protective layer 14 formed thereon.

In the above example, the recording layer 12 and the reflection layer 13 are formed on the transmission substrate having the tracking guide 3, and the recording layer 12 and the reflection layer 13 are not formed. This is an example in which another substrate 5 is bonded. In these cases, recording / reproduction is possible on only one side. The other substrate 5 may have no translucency, may be colored to maintain light resistance, or may have a surface provided with a character, pattern, or writable area.

On the other hand, two translucent substrates 1 having a recording layer 12 and a reflective layer 13 provided on a translucent substrate 1 having a tracking guide 3 are prepared. An optical information medium having a so-called double-sided recording / reproducing structure in which the optical information media are bonded together with their 13 sides facing each other can also be used.

[0034]

Next, embodiments of the present invention will be described with specific numerical values. (Example 1) An outer diameter of 120 mmφ, an inner diameter of 15 mmφ, and a thickness of 0.59 were obtained by resin molding using a stamper.
7 mm, a polycarbonate substrate having a refractive index of 1.59, and a half-value width of 0.31 μm and a depth of 140 on one main surface.
A light-transmitting substrate 1 having a tracking guide 3 with a pitch of 0.74 μm was prepared. In the land 8 between the tracking guides 3, the half width of the diameter d is 0.27.
A plurality of land pre-pits 6 having a variation of ± 0.02 μm are formed. In the portion of the tracking guide 3 adjacent to the land pre-pit 6 and the inner peripheral side of the translucent substrate 1, a raised portion 7 having the same height as the land 8 as shown in FIGS. The depth of the tracking guide 3 at the portion is 0. The dimension of the raised portion 7 along the longitudinal direction of the tracking guide 3 is 0.3 μm.
It is.

A trimethine dye (cyanine dye) is provided on the surface of the light-transmitting substrate 1 having the tracking guide 3.
Was spin-coated to form a film, thereby forming a recording layer 12 having a thickness of 60 nm. The leveling ratio when a solution of a trimethine dye (cyanine dye) was spin-coated was 0.38.
Met.

Further, gold was sputtered on the recording layer 3 to form a reflection layer 13. An ultraviolet-curing resin was spin-coated thereon, and the coating was cured by irradiating ultraviolet rays to form a protective layer 14. An adhesive made of an ultraviolet-curable resin was applied to the protective layer 14, a substrate 5 having the same material and shape as described above was bonded, and the adhesive was irradiated with ultraviolet rays to be cured and bonded. Thus, an optical information medium was produced.

With respect to the optical information medium thus manufactured, a signal was read from the land pre-pit 6 using an optical pickup (aperture ratio: 0.6) that emits a laser beam having a wavelength of 655 nm. 22. The signal had an excellent error rate of 1.0%.

Further, for this optical information medium, the same system as described above was used, and the recording power was 10 mW and the EFM-P
rus signal was recorded. After that, when the recording signal was read using an optical pickup (aperture ratio: 0.6) that emits a laser beam having a wavelength of 655 nm, the data signal could be read stably. The error rate of the data signal was as low as 50/8 ECC, and stable reproduction was possible. 61% signal modulation and 7.8% jitter
In each case, favorable results were obtained.

(Embodiment 2) In Embodiment 1 described above, FIG.
As shown in FIG. 8 and FIG. 8, the land pre-pit 6 formed on the land 8 is offset from the center of the land 8 by 0.07 μm toward the inner peripheral side of the land 1. Produced an optical information medium in the same manner as in Example 1.

With respect to the optical information medium thus produced, a signal was read from the land pre-pit 6 using an optical pickup (aperture ratio: 0.6) that emits a laser beam having a wavelength of 655 nm. 23. The signal had an excellent error rate of 1.0%.

Further, for this optical information medium, the same system as described above was used, and the recording power was 10 mW and the EFM-P
rus signal was recorded. After that, when the recording signal was read using an optical pickup (aperture ratio: 0.6) that emits a laser beam having a wavelength of 655 nm, the data signal could be read stably. The error rate of the data signal was as low as 35/8 ECC, and stable reproduction was possible. 62% signal modulation and 7.7% jitter
In each case, favorable results were obtained.

(Embodiment 3) In Embodiment 1 described above, FIG.
As shown in FIG. 10 and FIG. 10, a ridge 7 having a height of 70 nm is formed in a portion adjacent to the land land prepits 6 of the tracking guide 3 and the inner peripheral side of the light-transmitting substrate 1. An optical information medium was produced in the same manner as in Example 1 except that a light-transmitting substrate 1 having a depth of 70 nm was used.

With respect to the optical information medium thus produced, a signal was read from the land pre-pit 6 using an optical pickup (aperture ratio: 0.6) that emits a laser beam having a wavelength of 655 nm. 23. The signal error rate was as good as 0.7%.

Further, for this optical information medium, the same system as described above was used, and a recording power of 10 mW and an EFM-P
rus signal was recorded. After that, when the recording signal was read using an optical pickup (aperture ratio: 0.6) that emits a laser beam having a wavelength of 655 nm, the data signal could be read stably. The error rate of the data signal was as low as 30/8 ECC, and stable reproduction was possible. 63% signal modulation and 7.6% jitter
In each case, favorable results were obtained.

(Embodiment 4) FIG.
As shown in FIG. 1 and FIG. 12, the land adjacent to the land land prepits 6 of the tracking guide 3 and the inner peripheral side of the light-transmitting substrate 1 does not have a raised portion 7, and a length of 0.3
As a result, the half width of that portion is 0.2 μm, which is narrower than the other portion of the tracking guide 3, and the depth thereof is 140 nm, which is the same as the other portion of the tracking guide 3. An optical information medium was produced in the same manner as in Example 1 except that the transparent substrate 1 was used.

With respect to the optical information medium thus manufactured, a signal was read from the land pre-pit 6 using an optical pickup (aperture ratio: 0.6) that emits a laser beam having a wavelength of 655 nm. 20, the signal error rate was 1.2%, showing good characteristics.

For this optical information medium, the same system as described above was used, and a recording power of 10 mW and an EFM-Pl
The us signal was recorded. After that, when the recording signal was read using an optical pickup (aperture ratio: 0.6) that emits a laser beam having a wavelength of 655 nm, the data signal could be read stably. The error rate of the data signal was as low as 45/8 ECC, and stable reproduction was possible. Signal modulation 61%, jitter 7.7%
And a favorable result was obtained.

(Embodiment 5) In Embodiment 4 shown in FIG.
As shown in FIG. 3 and FIG. 14, the land land prepits 6 formed on the lands 8 extend from the center of the lands 8 to the transparent substrate 1.
An optical information medium was manufactured in the same manner as in Example 1 except that the light-transmitting substrate 1 offset by 0.1 μm on the inner peripheral side of was used.

Using the optical pickup (aperture ratio: 0.6) that emits a laser beam having a wavelength of 655 nm, a signal was read from the land prepit 6 with respect to the optical information medium thus produced. 20, the signal error rate was 0.9%, showing good characteristics.

For this optical information medium, the same system as described above was used, with a recording power of 10 mW and an EFM-Pl
The us signal was recorded. After that, when the recording signal was read using an optical pickup (aperture ratio: 0.6) that emits a laser beam having a wavelength of 655 nm, the data signal could be read stably. The error rate of the data signal was as low as 25/8 ECC, and stable reproduction was possible. 62% signal modulation and 7.7% jitter
In each case, favorable results were obtained.

(Comparative Example 1) In the first embodiment, there is no raised portion 7 or protruded portion 9 in a portion adjacent to the land land prepit 6 of the tracking guide 3 and the inner peripheral side of the translucent substrate 1, and the portion An optical information medium was manufactured in the same manner as in Example 1 except that the light-transmitting substrate 1 having a depth and width different from those of the other parts of the tracking guide 3 was used.

Using the optical pickup (aperture ratio: 0.6) that emits a laser beam having a wavelength of 655 nm, a signal was read from the land prepit 6 for the optical information medium thus produced. 21. Excellent characteristics with a signal error rate of 1.2%.

For this optical information medium, the same system as described above was used, and a recording power of 10 mW and an EFM-Pl
The us signal was recorded. Thereafter, when the recording signal was read using an optical pickup (aperture ratio: 0.6) that emits a laser beam having a wavelength of 655 nm, the reading of the data signal was unstable compared to Examples 1 to 5. The error rate of the data signal is 300/8 ECC and the first embodiment.
And reproduction was unstable. The degree of modulation of the signal was 62% and the jitter was 7.9%, which was a favorable result.

[0054]

As described above, in the optical information medium according to the present invention, when a recorded signal is optically read, a reading error caused by the presence of the land prepit 6 indicating address information is eliminated, and the data signal is read. Error rate can be kept low. This makes it possible to reproduce the recorded signal stably.

[Brief description of the drawings]

FIG. 1 is an exploded half-sectional perspective view showing an example of an optical information medium according to the present invention in a state before two substrates are bonded together.

FIG. 2 is a perspective view, partially in vertical section, showing the optical information medium.

FIG. 3 is a vertical sectional side view showing a main part of the optical information medium.

FIG. 4 is an essential part enlarged plan view showing an example of a light transmitting substrate used for the optical information medium.

FIG. 5 is a cross-sectional view taken along a line AA in FIG.

FIG. 6 is a sectional view taken along a line BB in FIG. 4;

FIG. 7 is an enlarged plan view of a main part showing another example of a light-transmitting substrate used for the optical information medium.

8 is a cross-sectional view taken along a line CC in FIG.

FIG. 9 is an enlarged plan view of a main part showing another example of a light-transmitting substrate used for the optical information medium.

FIG. 10 is a sectional view taken along a line DD in FIG. 9;

FIG. 11 is an enlarged plan view of a main part showing another example of a light-transmitting substrate used for the optical information medium.

FIG. 12 is a cross-sectional view taken along a line EE in FIG. 11;

FIG. 13 is an enlarged plan view of a main part showing another example of a light-transmitting substrate used for the optical information medium.

FIG. 14 is a cross-sectional view taken along a line FF in FIG.

[Explanation of symbols]

 Reference Signs List 1 translucent substrate 3 tracking guide 6 land prepit 8 land 12 recording layer 13 reflection layer

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Satoshi Ishikawa 6-16-20 Ueno, Taito-ku, Tokyo Inside Taiyo Denki Co., Ltd. (72) Inventor Toru Fujii 6-16-20 Ueno, Taito-ku, Tokyo Taiyo F-term (in reference) in Denki Co., Ltd. 5D029 JA04 JB47 KB03 WA27 WB11 WB17 WD16 5D090 AA01 BB03 CC04 CC14 DD03 EE13 GG10

Claims (6)

[Claims] 1. A light-transmitting substrate (1) that transmits recording light,
Recording layer (12) formed on this translucent substrate (1)
And a reflective layer (13) formed on the recording layer (12) and reflecting reproduction light, and optically readable by recording light incident from the light-transmitting substrate (1). In an optical information medium for recording various signals, a spiral groove-shaped tracking guide (3) is provided on the surface of the light-transmitting substrate (1) on which the recording layer (12) is formed. A land pre-pit (6) indicating address information is formed on a land (8) between the tracking guides (3) on the inner peripheral side of the translucent substrate (1) with respect to the land pre-pit (6). An optical information medium characterized in that the shape of a portion adjacent to the land prepit (6) is different from other portions of the tracking guide (3). 2. The tracking guide (3) located on the inner peripheral side of the translucent substrate (1) from the land prepit (6) has a depth adjacent to the land prepit (6). 2. The optical information medium according to claim 1, wherein the optical information medium is different from other parts. 3. The tracking guide (3) located on the inner peripheral side of the translucent substrate (1) from the land pre-pit (6) has a depth adjacent to the land pre-pit (6). 3. The optical information medium according to claim 2, wherein the optical information medium is shallower than the other parts. 4. The tracking guide (3), which is located on the inner peripheral side of the translucent substrate (1) with respect to the land prepit (6), has a width adjacent to the land prepit (6). 2. The optical information medium according to claim 1, wherein the optical information medium is different from the other parts. 5. The tracking guide (3) having a width adjacent to the land prepit (6) of the tracking guide (3) located on the inner peripheral side of the translucent substrate (1) from the land prepit (6). The optical information medium according to claim 4, wherein the optical information medium is narrower than other portions of the optical information medium. 6. The land pre-pit (6) is a land (8).
The optical information medium according to any one of claims 1 to 5, wherein the optical information medium is offset from the center of the transparent substrate (1) to the inner peripheral side of the transparent substrate (1).