JP2000311395A - Stamper, substrate for optical information medium, optical information medium and recording method thereof - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To enable an address signal to be reliably read from prepits during recording, and to eliminate an error in reading a signal indicating address information and recorded data when reading a recorded signal. An optical information medium includes a light-transmitting substrate that transmits recording light, and a recording layer formed on the light-transmitting substrate.
And a reflective layer 13 formed on the recording layer 12 and reflecting the reproduction light, and recording an optically readable signal by the recording light incident from the translucent substrate 1. It is. A spiral groove-shaped tracking guide 3 is provided on the surface of the translucent substrate 1 where the recording layer 12 is formed, and pre-pits 6 indicating address information are formed on lands 8 between the tracking guides 3. . This pre-pit 6
Are formed off the center of the land 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a stamper used during molding, a substrate for an optical information medium formed by the stamper, and an optical information medium on which optically reproducible information can be recorded using the substrate. Especially 630-670n
The present invention relates to a device having sector information detecting means optimal for a high-density recording medium recorded and reproduced by a short-wavelength red laser beam of m.

[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 the maximum recording capacity is about 4.7 GB and the video and audio are recorded on average about 133 minutes on one disc.

Hitherto, in a recordable CD such as a CD-R, a spiral tracking guide meanders (Wo).
bble) FM modulation and ATIP (Absolute Time In Pregr)
oove). On the other hand, in a recordable DVD such as a DVD-R, address information such as position information on an optical information medium is obtained by pre-pits provided in advance in a land portion between a tracking guide and wobbles, instead of ATIP.

[0006]

The pre-pits employed in the DVD which is a high-density recording medium as described above are read together with the pits of the recording signal by an optical pickup. At this time, the optical pickup moves along a tracking guide. Since the tracking servo is performed, in a normal state, the pre-pits and the pits on which the data signals formed on the grooves are recorded are discriminated and read. However, depending on the shape and size of the pre-pits, the pre-pits may be mixed with the RF signal obtained from the data signal recording pits and read. In this case, an error occurs in reading the data signal.

In DVD-Rs and DVD-RWs, prepits are necessary for obtaining address information such as position information on an optical information medium at the time of recording. However, it is not used at the time of reproduction, and RF indicating recording data is used.
The mixing of the signal from the pre-pit into the signal
This may cause an error in reading the RF data signal. However, on the other hand, if the pre-pits are difficult to read during recording, information such as addresses during recording cannot be read normally, and the recording becomes unstable, thereby making it impossible to reproduce the recording signal itself.

In view of the above-mentioned problems associated with reading pre-pits for reading address information of an optical information medium corresponding to high-density recording, the present invention aims to access an unrecorded area and reach a recording start position. The address signal can be reliably read from the pre-pit during recording, including the movement information when moving the pickup, and the signal obtained from the pre-pit indicating the address information and the tracking when reading the recorded signal optically. An optical information medium, an optical information medium substrate, and an optical information medium capable of eliminating a reading error due to interference with recording data read from a pit on a guide and eliminating mixing of a signal obtained from a pre-pit into a data signal during reproduction. It is to provide a stamper for forming a substrate.

[0009]

In order to achieve the above object, according to the present invention, a pre-pit 6 provided on a land 8 indicating address information is formed so as to be deliberately shifted from the land 8, thereby achieving tracking. Increase the strength to the error signal and weaken the leakage to the RF signal,
The RF signals obtained from the pits on the groove 3 can be clearly distinguished from each other to prevent them from being erroneously read.

A stamper according to the present invention is a stamper which is formed concentrically or spirally and has an uneven step. A concave portion of the stamper is connected to at least one of a convex portion adjacent to the concave groove. It is characterized by having a protruding portion. Further, the optical information medium substrate according to the present invention is an optical information medium substrate which is formed concentrically or spirally and is resin-molded by a stamper having uneven steps, wherein the substrate has a concave portion of the stamper. A pre-pit indicating address information is provided by a projecting portion which is provided and is connected to at least one of the convex portions adjacent to the concave groove.

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. And a reflection layer 13 that reflects light, and records an optically readable signal by the recording light incident from the translucent substrate 1. According to the present invention, in such an optical information medium, 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. , And pre-pits 6 indicating address information are formed, and the pre-pits 6 are formed off the center of the lands 8. As a result, the pre-pit 6 is open on the tracking guide 3 side adjacent to the land 8.

In such a stamper and a substrate for an optical information medium formed by the stamper, and in the optical information medium using the substrate, the prepits 6 are formed to be shifted from the center of the land 8. More specifically, since the prepit 6 is formed so as to be shifted from the center of the land 8 in the inner circumferential direction of the disc, the prepit is formed as a prepit closer to the center of the beam spot during tracking. It is possible to obtain a larger signal amplitude than when the prepit is formed at the center of the land, and it is possible to reliably read the signal.

[0013] In addition, by configuring as described above,
The shape of the prepit 6 can be made smaller than when the prepit 6 is formed at the center of the land 8. This is because the pre-pits 6 are offset from the center of the lands 8 in the inner circumferential direction of the disk as described above, so that a larger signal amplitude is obtained than when the pre-pits are formed at the center of the lands 8. In this case, the shape of the prepit 6 can be physically reduced to a readable level (for example, the signal amplitude when the prepit 6 is formed at the center of the land 8). Pre-pit signal is R
Even when the signal leaks into the F signal, when it is decoded into the EFM signal, it becomes sufficiently smaller than the time length of the minimum signal as the data signal. It is possible to prevent reading of a signal by the pre-pit.

For example, when a data pit formed on the tracking guide 3 is read while tracking the optical pickup along the tracking guide 3, the signal obtained from the pre-pit 6 is further different from the signal obtained from the data pit. It becomes weak. This allows
The signal of the pre-pit 6 mixed into the RF signal obtained from the data pit becomes weak, and the mixing of noise into the data signal hardly causes a problem.

The pre-pit 6 is located at the center of the land 8
It is preferable that the light transmitting substrate 1 is shifted in the inner circumferential direction.
This is because, as described above, by forming the prepits closer to the center of the beam spot during tracking, a larger signal amplitude is obtained as a reproduction signal of the prepits than when the prepits are formed at the center of the land 8. is there.

The pitch p of the tracking guide 3 is 0.7.
The half-width w is 0.23 μm ≦ w ≦
It is better to be in the range of 0.38. The half width d of the pre-pit 6 is preferably set to 0.20 μm ≦ d ≦ 0.33. From this relationship, the ratio w / d of the half width w of the tracking guide 3 to the half width d of the pre-pit 6 is 0.5 ≦ w / d.
≦ 1.7. The offset dimension δ of the prepit 6 from the center of the land 8 depends on the width of the land 8 but is 0 μm.
.Ltoreq..delta..ltoreq.0.2 .mu.m, and the width 1 from the boundary between the tracking guide 3 and the land 8 to the prepit 6 is preferably in the range of 0 .mu.m.ltoreq.0.2 .mu.m.

[0017]

Embodiments of the present invention will now be described specifically and in detail with reference to the drawings. As an example of an 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 bonding both sides is shown in FIGS. The translucent substrate 1 is a transparent disk-shaped substrate having a center hole 4 at the center. The translucent substrate 1 is generally made by injection molding a transparent resin such as polycarbonate and polymethyl methacrylate (PMMA).

Here, in molding the light-transmitting substrate 1, a stamper 21 formed concentrically or spirally as shown in FIG. 7 and having uneven steps is used. The concave portion 23 of the stamper 21 has at least one of the convex portions 24 adjacent to the concave portion 23, and in this case, the convex portion 24 on the inner peripheral side.
Is provided. In addition,
The connecting portion between the protruding portion 22 and the protruding portion 24 has a shape in which sagging occurs or swells.

In the optical information medium substrate resin-molded by the stamper 21, a projecting land 8 is formed on the substrate 1 by the concave portion 23 of the stamper 21, and the stamper 2
The concave tracking guide 3 is formed on the substrate 1 by the one protrusion 24. Further, a concave pre-pit 6 indicating address information is provided on the substrate 1 by a projecting portion 22 formed in a concave portion 23 of the stamper 21 so as to be continuous with the convex portion 24 of the stamper 21. The pre-pit 6 is formed on a part of the land 8 adjacent to the tracking guide 3 so as to be continuous with the tracking guide 3 on the substrate 1.

A clamping area is set outside the center hole 4 on one side of the translucent substrate 1 having translucency, and an 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 FIGS. 3 to 6, in the land 8 between the tracking guides 3, when recording a signal on the optical information medium, a concave pre-pit 6 for indicating address information or the like is appropriate. It is formed at intervals. The pre-pit 6 is provided together with the tracking guide 3 together with the translucent substrate 1.
Is formed in advance at the time of injection molding.

As shown in these figures, the pre-pit 6
Are formed offset from the center of the land 8 by an offset dimension δ. For this reason, the pre-pit 6 is open at one edge of the land 8. The direction of displacement of the prepit 6 with respect to the center of the land 8 is the same,
In the illustrated example, the pre-pit 6 is open to the left of the land 8 in FIG. A raised rim 7 is formed in this open portion. As a matter of course, the depth of the rim 7 is lower than the depth of the tracking guide 3 or the pre-pit 6, that is, the height of the land 8 from the bottom surface of the tracking guide 3. The rim 7 may be interrupted on the way.

Since the rim portion is lower than the height of the land 8, the contribution to the amount of reflected light at the land portion during laser beam irradiation is reduced. In order to maximize the LPP signal amplitude at this time, it is advantageous to reduce the amount of reflected light at the land portion, and it is desirable that the rim portion be low.

The offset dimension δ of the prepit 6 with respect to the center of the land 8 depends on the width of the land 8 but is 0 μm.
It is preferable that m ≦ δ ≦ 0.2 μm, and the width l from the boundary between the tracking guide 3 and the land 8 to the pre-pit 6 be in the range of 0 μm ≦ l ≦ 0.2 μm. By the way, the pitch p = 0.
The half-width w is 0.23 μm ≦ w ≦ 0.
It is in the range of 38 μm.

The diameter d of the prepit 6 is made different from the length of the pit formed on the optical information medium during recording. For example, in a DVD, the data pit length is about 0.4 to about 1.9.
μm, but the diameter d of the pre-pit 6 is made shorter than the minimum pit length of 0.4 μm. More specifically, the diameter d of the pre-pit 6 is set to 50 to 83% of the minimum pit length.
For example, in a DVD, the minimum pit length is three channel clocks, but the length of the pre-pit 6 is set to 1.5 to 2.
The length is 5 channel clocks. As specific dimensions, the diameter d of the prepit 6 is set to 0.20 μm ≦ d ≦ 0.
33 μm. From this relationship, Tracking Guide 3
The ratio w / d of the half width w of the pre-pit 6 and the half width d of the pre-pit 6 is 0.5 ≦ w / d ≦ 1.7. In this way, necessary signal outputs can be obtained for each of the data pits formed on the tracking guide 3 and the pre-pits formed on the lands 8, and the two signals do not interfere with each other. Thus, signal leakage due to prepending can be suppressed.

As shown in FIG. 3, both ends of the pre-pit 6 formed in the land 8 are substantially curved outwardly from the outer periphery of the pre-pit when viewed in plan, as shown by reference numeral 6a. Tracking guide 3 and land 8
It is desirable to form it so as to be in contact with the boundary portion between.
By doing so, the surface shape of the pre-pit 6 expands at that portion, so that the contribution of the land 8 to the amount of reflected light is small when viewed optically, and the pre-pit signal amplitude can be increased. Therefore, even when the shape of the pre-pits varies and becomes smaller than the reference shape, the output signal of the pre-pit signal at the time of the reference shape can be secured, and the reading error of the pre-pit signal can be reduced.

As shown in FIGS. 1, 2, 5, and 6, a recording layer 12 is formed on the main surface of the data recording area of the light transmitting substrate 1. 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. 5 and 6 are cross-sectional views of the translucent substrate 1 in the radial direction. As is clear from FIG. 6, the pre-pit 6 is shifted to the left side of the land 8, that is, to the inner circumferential side of the disk, and as a result, the left side of the land 8 is open. Further, a raised rim 7 shallower than the depth of the tracking guide 3 is formed in a portion of the pre-pit 6 which is open on one side of the land 8.

Here, generally, the intensity of the laser beam has the strongest normal distribution at its center, and when the prepit 6 is offset to the inner periphery of the land 8 as described above, the tracking Since the pre-pit 6 is closer to the center of the beam, more diffraction intensity can be obtained than when the pre-pit is located at the center of the land 8. The pre-pit 6 is for obtaining a signal serving as address information of the optical information medium. However, the pre-pit 6 may be used together with the pre-pit 6 to obtain rotation control information of the tracking guide 3 by wobble.

As shown in FIGS. 1, 2, 5 and 6,
On the recording layer 12 formed as described above, a reflection layer 13 made of a metal film of gold, aluminum, silver, copper, or the like or an alloy film thereof is formed. Further, a protective film 14 such as an ultraviolet curable resin is formed on the reflective layer 13. As shown in FIGS. 1 and 2, another substrate 5 is prepared in addition to the light-transmitting substrate 1. The substrate 5 is of the same size and made of the same material as the light-transmitting substrate 1, but has, on its main surface, a tracking guide 3 such as the light-transmitting substrate 1, a recording layer 12, and a reflective layer. 13 is not provided.
Needless to say, the recording layer 1 is formed on the substrate 5 having the tracking guide 3 similarly to the light-transmitting substrate 1.
2 and the reflective layer 13 can 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 surface of the translucent substrate 1 on which the recording layer 12 and the reflective layer 13 are formed is bonded.

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 light-transmitting substrates 1 having a recording layer 12 and a reflective layer 13 provided on a light-transmitting 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. In FIGS. 1 and 2, reference numeral 9 denotes a ridge 9 formed in a ring shape outside the data recording region r on the recording light incident surface side on the front side of the translucent substrate 1. This prevents the recording surface from touching the surface of another optical information medium when the optical information medium is superimposed.

[0033]

Next, embodiments of the present invention will be described with specific numerical values. (Example 1) A photosensitizer (photoresist) is applied very thinly on a polished glass substrate, and a laser beam is spirally moved from the inner circumference to the outer circumference while rotating the glass disk to perform cutting. The cutting machine is
It is called LBR (Laser Beam Recorder) and has a wavelength of 35
A krypton / argon laser of 1 to 458 nm is used as a light source. This laser beam is a mastering signal applied to an optical modulator that can adjust the intensity of light that is electrically transmitted, and whips to irradiate a spot on a rotating photosensitive film in a spiral manner. At that time, the laser beam that has passed through another irradiation path is
It is turned off, and the exposed portion of the photosensitive film is dissolved with a dedicated developer to form a concave groove and a pre-pit in that portion. After that, the surface is coated with a conductive agent, and the surface is coated with Ni using the electrode as an electrode. Further, a mother stamper can be obtained by plating the surface of the master stamper as an electrode in the same manner as described above and peeling it off.

The resin is molded using the stamper thus formed, so that the outer diameter is 120 mm and the inner diameter is 15 m.
A polycarbonate substrate having a diameter of mφ, a thickness of 0.597 mm and a refractive index of 1.59, and a half-value width of 0.3 on one main surface.
A translucent substrate 1 having a tracking guide 3 of 1 μm, a depth of 140 nm, and a pitch of 0.74 μm was prepared. The land d between the tracking guides 3 has a diameter d.
Has a half width of 0.27 μm, and its variation is ± 0.02 μm.
A plurality of m pre-pits 6 are formed. The pre-pits 6 are shifted by 0.1 μm at the maximum, 0.05 μm at the minimum, and 0.07 μm on average. A solution of a cyanine dye was spin-coated on the surface of the light-transmitting substrate 1 having the tracking guide 3 to form a film.

Further, Au was sputtered on the recording layer 3 to form a reflective layer 13. An ultraviolet-curable resin (SD211 manufactured by Dainippon Ink and Chemicals, Inc.) was spin-coated thereon, and was cured by irradiating it with 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 having the same material and shape as described above was adhered, 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, an address signal was read using an optical pickup (aperture ratio: 0.6) that emits a laser beam having a wavelength of 637 nm. As a result, the address information could be stably taken out. . In addition, using this system, a recording power of 10 mW and an 8/1
Six modulation signals (8 bits converted to 16 bits) were recorded. When the optical information medium after the recording was reproduced by a DVD player, the PI error of reading the data signal was 8E.
3 counts per CC block (average per minute)
And stable reproduction was possible. Preferable results were obtained in which the modulation degree of the recorded signal was 61%, the maximum value of the length error of the pit and land 8 of each signal was 6.0 ns, and the jitter was 7.5%.

(Embodiment 2) In the same manner as in Embodiment 1 except that the half width of the diameter d of the land prepit 6 is 0.28 μm and the variation is ± 0.02 μm. Optical media. Using the optical pickup (aperture ratio: 0.6) that emits laser light having a wavelength of 650 nm, the sector information was read from the optical information medium thus manufactured, and the address information could be stably extracted. Using the same system, an 8/16 modulated signal (8 bits converted to 16 bits) was recorded at a recording power of 10.5 mW. The optical information medium after this recording is
When the data was read by a DVD player, the PI error of reading the data signal was 5 counts per 8 ECC blocks (1 count).
Average value per minute), and stable reproduction was possible. The desirable results were obtained when the modulation degree of the recorded signal was 65%, the maximum value of the length error of the pit and land 8 of each signal was 5.8 ns, and the jitter was 7.3%.

Comparative Example 1 In Example 1, the offset amount of the prepit 6 from the center of the land 8 in the disk outer peripheral direction was 0.1 μm, the half width d of the land prepit 6 was 0.41 μm, and the tracking guide 3 was used. In the same manner as in Example 1 except that the half width w of the light guide was 0.20 μm (the half width d of the land pre-pit 6 and the ratio w / d to the half width w of the tracking guide 3 = 0.49). I made an information medium. For the optical information medium thus produced, the wavelength 63
When the sector information was read using an optical pickup (aperture ratio: 0.6) that emits a laser beam of 5 nm, the address information could be taken out stably. Using the same system, an 8/16 modulated signal (8 bits converted to 16 bits) was recorded at a recording power of 10.0 mW. When the optical information medium after recording is reproduced by a DVD player, the PI error of reading the data signal is 300 counts per 8 ECC blocks (average value per minute), which is not preferable for data reproduction. there were. The modulation degree of the recorded signal was 65%, the maximum value of the length error of the pit and land 8 of each signal was 6.5 ns, and the jitter was 9%.

(Comparative Example 2) In Example 1, the displacement of the land pre-pit 6 was 0.3 μm at the maximum and 0.2 μm at the minimum.
m, the same as Example 1 except that the average was 0.25 μm.
An optical information medium was made in the same manner as described above. With respect to the optical information medium thus produced, an address signal was read using an optical pickup (aperture ratio: 0.6) that emits a laser beam having a wavelength of 650 nm. As a result, no address information could be read.

[0040]

As described above, in the optical information medium according to the present invention, a signal is optically recorded on an optical information medium compatible with high-density recording by using an optical pickup, and an address signal is reliably recorded from prepits during recording. When reading recorded signals optically, eliminate errors in reading signals obtained from land pre-pits indicating sector information and recording data read from pits on tracking guides, The address information at the time of recording and the data signal at the time of reproduction can be accurately separated and read.

[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 partial longitudinal sectional perspective view showing the optical information medium.

FIG. 3 is a main part plan view showing a part of a light-transmitting substrate used for the optical information medium.

FIG. 4 is a perspective view showing a cross section at a position AA in FIG. 3;

FIG. 5 is a vertical sectional side view of a main part of the optical information medium.

FIG. 6 is an enlarged vertical sectional side view of a main part of the optical information medium.

FIG. 7 is a perspective view of a stamper.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 translucent substrate 3 tracking guide 6 pre-pit 8 land 12 recording layer 13 reflection layer 21 stamper

Claims (11)

[Claims] 1. A stamper formed concentrically or spirally and having an uneven step, wherein a concave portion (23) of the stamper has a convex portion (2) adjacent to the concave portion (23).
Projection (22) leading to at least one of 4)
A stamper characterized in that a stamper is provided. 2. An optical information medium substrate which is formed concentrically or spirally and is resin-molded by a stamper (21) having an uneven step.
A projecting land (8) is formed on the substrate (1) by the concave portion (23) of the stamper (2).
4), a concave tracking guide (3) is formed on the substrate (1), and is formed in the concave portion (23) of the stamper (21) so as to be continuous with the convex portion (24) of the stamper (21). A concave pre-pit (6) indicating address information on the substrate (1) by the raised protrusion (22).
The pre-pit (6) is formed on a part of a land (8) adjacent to the tracking guide (3) so as to be continuous with the tracking guide (3) on the substrate (1). For optical information media 3. A translucent 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. An optical information medium characterized in that a pre-pit (6) indicating address information is formed on a land (8) between the lands (8), and the pre-pit (6) is formed off the center of the land (8). 4. The pre-pit (6) is formed off the center of the land (8), so that the pre-pit (6) is open to the tracking guide (3) adjacent to the land (8). The optical information medium according to claim 3, wherein: 5. The optical information medium according to claim 4, wherein a rim is formed at an opening of the pre-pit. 6. An opening of a pre-pit (6) formed on a land (8), both ends of which are opposite to the inside of the pre-pit in a plan view and have a substantially curved tracking guide (3). The optical information medium according to claim 4, wherein the optical information medium is formed so as to be in contact with a boundary between the land and the land (8). 7. The optical information medium according to claim 3, wherein the pre-pits (6) are displaced from the center of the land (8) in an inner circumferential direction of the translucent substrate (1). 8. The optical information medium according to claim 3, wherein an offset dimension δ of the pre-pit from the center of the land is in a range of 0 μm ≦ δ ≦ 0.2 μm. 9. The width l from the boundary between the tracking guide (3) and the land (8) to the pre-pit (6) is:
4. The optical information medium according to claim 3, wherein 0 μm ≦ l ≦ 0.2 μm. 10. The half width w of the tracking guide (3).
And the ratio w / d of the half width d of the land pre-pit (6) is
4. The optical information medium according to claim 3, wherein 0.5 ≦ w / d ≦ 1.7. 11. A translucent substrate (1) that transmits recording light.
And a recording layer (1) formed on the translucent substrate (1).
2) and an optical information medium having a reflective layer (13) formed on the recording layer (12) and reflecting the reproduction light by the recording light incident from the translucent substrate (1). In a method for recording an optical information medium for recording an optically readable signal, the optical information medium according to any one of claims 3 to 11, wherein the recording light incident from the light-transmissive substrate (1) is used. An optical information medium for recording an optically readable signal while tracking along the tracking guide (3).