JP2002260286A - Information recording medium, its reproducing device and recording device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an information recording medium that reduces cross erasing and to provide a reproducing device and recording device. SOLUTION: The base 13 has at least a fine pattern 20 of parallel grooves consisting of grooves G and lands L alternately formed, a recording layer 12 formed on this pattern 20 and a light transmissive layer 11 0.07-0.12 mm thick further on the recording layer 12. When P represents the pitch of the groove G or land L, λ the wavelength of the reproducing light, and NA the opening area ratio of the objective lens, the fine pattern is made to the relation P<λ/NA and λ is 350-450 nm, NA is 0.75-0.9, and recording is made only either on the grooves G or the lands L on the basis of either the reflectance of 5% or more or the phase difference.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reproducing apparatus for reading out information by making a relative movement with respect to an information recording carrier, and an information recording carrier used for the recording apparatus, and more particularly to recording and / or reproducing by optical means. The present invention relates to an information record carrier, a reproducing device thereof, and a recording device.

[0002]

2. Description of the Related Art Hitherto, there has been a system for reading information by moving an information record carrier relative to each other, and an optical means, a magnetic means, a capacitance means and the like are used for reproducing the system. Of these, systems that perform recording and / or reproduction by optical means are deeply penetrating into everyday life. For example, as a read-only type information recording carrier using light having a wavelength of λ = 650 nm, a DVD video in which image information is recorded in advance, a DVD-ROM in which programs are recorded in advance, and music information are recorded in advance. DVD audio and SACD are known.

Further, DVD-R is a recordable / reproducible information recording carrier using a dye, and DVD-RAM, DVD is a recordable / reproducible information recording carrier using a phase change.
-RW and DVD + RW include ASMO, iD, and GIGAMO as recordable / reproducible information record carriers using magneto-optics. On the other hand, in order to increase the recording density of the information record carrier,
Research on shortening the wavelength of lasers has been ongoing for many years. The second harmonic oscillation element and the gallium nitride-based compound semiconductor light-emitting element (for example, described in Japanese Patent No. 2778405) recently invented emit light in the vicinity of λ = 350 to 450 nm. It can be a light emitting element.

Further, the design of an objective lens corresponding to a wavelength in the vicinity of this is also progressing. In particular, a lens having an NA (numerical aperture) exceeding 0.7 used in DVD and having 0.7 or more is under development. is there. As described above, an information recording carrier reproducing apparatus in which λ is reduced to 350 to 450 nm and NA is 0.7 or more is being developed.
It is expected that an optical disk system far exceeding the recording capacity of VD will be developed.

[0005] By using a short wavelength exceeding the DVD and a high NA as described above, an information recording carrier having a remarkably high recording density can be designed. However, since the coma aberration when the information recording carrier is tilted becomes extremely large, an information recording carrier having a light transmitting thickness much smaller than that of a DVD is required. Specifically, DV
A disk system called an R land groove has been proposed. In this system, a light-emitting element having a wavelength of 405 nm and an objective lens having an NA of 0.85 are used, and the thickness for transmitting light is designed to be 0.1 mm.

A conventional information recording carrier will be described with reference to FIGS. FIG. 18 is a sectional view showing a conventional information recording carrier. FIG. 19 is an enlarged plan view of a conventional information recording medium viewed from above. As shown in FIG.
The information recording carrier 100 includes a recording layer 120 sequentially formed on a support 130 and a light transmitting layer 110. Support 1
30 has a fine pattern 200 formed thereon, on which the recording layer 120 is directly formed. The fine pattern 200 has a fine pattern including a land portion L and a groove portion G. At the time of recording, as shown in FIG. 19, a recording mark M is formed on both the land portion L and the groove portion G (so-called land-groove recording). Focusing on the dimensions of the fine pattern 200, if the shortest distance between the center of the groove portion G and the center of the groove portion G is a pitch P (the shortest distance between the center of the land portion L and the center of the land portion L is also the pitch P), The reproducing spot diameter S is formed so as to satisfy the relationship of P> S.

The reproduction spot diameter S is calculated from the wavelength λ of the laser used for reproduction and the numerical aperture NA of the objective lens.
= Λ / NA, in other words, the pitch P is designed to satisfy the relationship of P> λ / NA.

[0008] The information recording carrier 100 includes a light transmitting layer 110.
After reproducing light enters from the side to read information recorded in the recording layer 120, the information is reflected on the surface of the recording layer 120, taken out from the light transmitting layer 110 side, and reproduced.

[0009]

However, the present inventor has actually manufactured the information recording carrier 100 on a trial basis and has a wavelength of 350 to 350 nm.
Light emitting device emitting at a single wavelength in the range of 450 nm and high N
When a recording / reproducing experiment was performed using an A objective lens (NA 0.75 to 0.9), it was found that the cross erase phenomenon was remarkable. The cross-erase phenomenon is a phenomenon in which, for example, when information is recorded on the land L, the information is superimposed on a signal previously recorded on the groove G. In other words, the information recorded in the land portion L is erased by the information recorded in the groove portion G. This phenomenon can also be seen in the opposite case, that is, when information is recorded on the groove portion G and the recorded information on the land portion L is observed.

[0010] When the cross erase occurs as described above, the next erase occurs.
Since the information on the contact tracks is damaged, a large amount of information
The amount of loss information is very large in the stem
Therefore, the effect on users is enormous. Because of this,
Using the information recording carrier 100, the land portion L or the groove
It is conceivable to record in only one of section G
However, the recording capacity has decreased, and
The merit of the information record carrier is reduced. Therefore,
Reduce cross-erase to solve conventional problems
Record carrier, high-density-recorded information record carrier, reproducing apparatus and recording medium
It is intended to provide a recording device. In particular, 350-4
Information recording responsible for recording / reproducing at 50 nm wavelength
To provide a body, its playback device and its recording device.
Target.

[0011]

According to a first aspect of the present invention, there is provided a support having a fine pattern comprising a continuous body of substantially parallel grooves in which grooves and lands are alternately formed, And a light-transmitting layer formed on the recording layer and having a thickness of 0.07 to 0.12 mm. The pitch of the groove portion or the land portion is P, Is the wavelength of λ and the numerical aperture of the objective lens is NA, the fine pattern is P <λ / NA
Λ is 350 to 450 nm
Where the NA is 0.75 to 0.9, and the reflectance difference or the phase difference performed so that the reflectance is 5% or more only in one of the groove portion and the land portion. An information record carrier characterized in that recording based on at least one of the following has been performed. 2. The information record carrier according to claim 1, wherein recording based on at least one of the reflectance difference and the phase difference is selectively performed only on the land portion. Further, the reflectance is 12 to
2. The information recording medium according to claim 1, wherein the information recording medium has a range of 26%. According to a second aspect, the recording layer includes:
2. The information recording carrier according to claim 1, wherein the information recording carrier is a phase change material. In a third aspect, the phase change material is Ge-Sb-Te, Ag-In-Te-Sb, Cu
The information recording medium according to claim 2, wherein the information recording medium is an alloy material containing at least one of -Al-Sb-Te and Ag-Al-Sb-Te. A fourth invention provides the information recording carrier according to any one of claims 1 to 3, wherein a hard coat layer is provided on a side of the light transmitting layer opposite to the recording layer. The fifth invention provides the information recording carrier according to any one of claims 1 to 4, wherein auxiliary information is shape-recorded on a part or all of the fine pattern by amplitude modulation. . The sixth invention provides the information recording carrier according to any one of claims 1 to 4, wherein auxiliary information is shape-recorded in a part or all of the fine pattern by frequency modulation. . The seventh invention provides the information recording carrier according to claim 6, wherein the frequency modulation is a frequency modulation in which a phase is selected such that a wave is continuous at a frequency switching point. The eighth invention provides the information recording carrier according to any one of claims 1 to 4, wherein auxiliary information is shape-recorded in part or all of the fine pattern by phase modulation. . The ninth aspect of the present invention is the information recording carrier according to claim 6 or 7, wherein a phase difference between a high frequency portion and a low frequency portion constituting the frequency modulation is ± π / 2.5. A tenth invention provides the information record carrier according to claim 6 or 7, wherein a phase difference between a high frequency part and a low frequency part constituting the frequency modulation is ± π / 4. The eleventh invention is characterized in that the auxiliary information is data which has been subjected to baseband modulation so that the continuation of the same bit is limited to a predetermined value or less in advance. An information record carrier is provided. A twelfth invention provides the information record carrier according to claim 11, wherein the baseband modulation is a Manchester code. Thirteenth
The present invention provides the information recording carrier according to any one of claims 5 to 12, wherein the auxiliary information is recorded while being dispersed in a part of the fine pattern.
According to a fourteenth aspect, the wavelength of the reproduction light is λ and RIN-125
a light emitting element having a noise of dB / Hz or less, and a numerical aperture N
A reproducing apparatus having at least an objective lens of A, and reproducing an information recording carrier having a fine pattern composed of a substantially parallel groove continuous body in which groove portions and land portions are alternately formed, wherein λ is 14. The information recording carrier according to claim 1, wherein the information recording carrier is mounted at 350 to 450 nm and the NA is 0.75 to 0.9, and the reproduction light is applied to only one of the groove portion and the land portion. And a reproducing apparatus characterized in that the reproduction is performed. 15. The reproducing apparatus according to claim 14, wherein the reproducing is performed by selectively irradiating the land with the reproducing light. Fifteenth
In the invention of the present invention, the wavelength of the recording light is λ, and RIN-125 dB /
An information recording carrier having at least a light emitting element having a noise of not more than Hz and an objective lens having a numerical aperture NA, and having a fine pattern of a substantially parallel groove continuous body in which groove portions and land portions are alternately formed. A recording apparatus for recording, wherein the λ is 350 to 450 nm and the NA is 0.75
14. A recording apparatus comprising: mounting the information recording medium according to claim 1; and irradiating only one of the groove portion and the land portion with the recording light. I will provide a. 16. The recording apparatus according to claim 15, wherein recording is performed by selectively irradiating the land with the recording light.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a sectional view showing an information recording carrier according to the first embodiment of the present invention. FIG.
FIG. 2 is an enlarged plan view of the information recording carrier according to the first embodiment of the present invention as viewed from above. FIG. 3 is a sectional view showing an information recording carrier according to a second embodiment of the present invention. FIG.
FIG. 8 is a sectional view showing an information recording carrier according to a third embodiment of the present invention. FIG. 5 is a sectional view showing an information recording carrier according to a fourth embodiment of the present invention. FIG. 6 is a sectional view showing an information recording carrier according to a fifth embodiment of the present invention.
FIG. 7 is an enlarged plan view showing an amplitude modulation address recorded on the information recording carrier in the present invention. FIG. 8 is an enlarged plan view showing a frequency modulation address recorded on the information recording carrier in the present invention. FIG. 9 is an enlarged plan view showing the phase modulation address recorded on the information recording carrier in the present invention. FIG. 10 is an enlarged plan view showing the phase modulation address recorded on the information recording carrier in the present invention. FIG. 11 is a diagram showing changes in basic data before and after baseband modulation. FIG. 12 is a diagram illustrating a specific example of a change in a data string before and after baseband modulation. FIG. 13 is a block diagram showing a first reproducing apparatus according to the present invention. Figure 1
FIG. 4 is a diagram showing the relationship between the reflectance and the error rate.
FIG. 15 is a diagram showing the reflectance and the reproduction characteristics of Examples 1 to 7 and Comparative Examples 1 and 2. FIG. 16 shows a second embodiment of the present invention.
FIG. 2 is a block diagram showing a reproducing apparatus of FIG. FIG. 17 is a block diagram showing a recording apparatus according to the present invention.

A first embodiment of the present invention will be described with reference to FIGS. The information recording carrier 1 according to the first embodiment of the present invention includes at least a recording layer 12 sequentially formed on a support 13 on which an uneven fine pattern 20 is formed, and a light transmitting layer 11. The unevenness in the fine pattern 20 forms a substantially parallel groove continuous body. The information recording carrier 1 is a reproduction-only device having a light emitting element that emits light at a single wavelength in the range of 350 to 450 nm and an objective lens having an NA of 0.75 to 0.9. Further, the shape of the information recording carrier 1 may be a disk shape, a card shape or a tape shape. The shape may be circular, square, or elliptical. Further, a hole may be formed.

Here, the support 13, the recording layer 12, and the light transmitting layer 11 will be described in detail. The support 13 is a base having a function of mechanically holding the recording layer 12 and the light transmitting layer 11 formed thereon. As this material, any one of synthetic resin, ceramic, and metal is used. Representative examples of synthetic resins include polycarbonate and polymethyl methacrylate, polystyrene, polycarbonate / polystyrene copolymer, polyvinyl chloride,
Various thermoplastic resins and thermosetting resins such as alicyclic polyolefins and polymethylpentenes, and various types of energy ray curable resins (including examples of ultraviolet curable resins, visible light curable resins, and electron beam curable resins) can be suitably used. . Note that these may be synthetic resins containing metal powder or ceramic powder.

As typical examples of the ceramic, soda lime glass, soda aluminosilicate glass, borosilicate glass, quartz glass and the like can be used. As a typical example of a metal, a metal plate having no light-transmitting property such as aluminum can also be used. The thickness of the support 13 is preferably 0.3 to 3 mm, and more preferably 0.5 to 2 mm because of the necessity of mechanical holding. When the information recording carrier 1 is disk-shaped, it is most preferable that the total thickness of the support 13, the recording layer 12, and the light-transmitting layer 11 be 1.2 mm for compatibility with a conventional optical disk. desirable.

The recording layer 12 is a thin film layer having a function of reading information or recording or rewriting information. In the recording layer 12, information is recorded on either the land L or the groove G. This recording layer 12
A material that causes a change in the reflectance and / or the refractive index before and after recording is used. Examples of the material of the recording layer 12 include a phase change material and a dye material which cause a change in reflectance and / or a change in refractive index between amorphous and crystal due to thermal recording.

Ge-Sb-Te is used as the phase change material.
System, Ag-In-Te-Sb system, Cu-Al-Sb-T
e type and Ag-Al-Sb-Te type. These notes
Cu, Ba, Co, Cr, N
i, Pt, Si, Sr, Au, Cd, Li, Mo, M
n, Zn, Fe, Pb, Na, Cs, Ga, Pd, B
i, Sn, Ti, V, Ge, Se, S, As, Tl, I
at least one selected from the group consisting of n, Pd, Pt, and Ni
0.01 atomic% or more and less than 10 atomic% in total of the above elements
It can also be contained. The composition of each element is, for example,
Ge as a Ge-Sb-Te system_TwoSb_TwoTe_Five, Ge₁Sb
_TwoTe_Four, Ge₈Sb₆₉Te_{twenty three}, Ge₈Sb₇₄Te₁₈, Ge_Five
Sb₇₁Te_{twenty four}, Ge_FiveSb₇₆Te₁₉, Ge_TenSb₆₈Te_{twenty two},
Ge_TenSb₇₂Te ₁₈, Ge-Sb-Te based Sn, In
Ag-In-Sb-Te system with added metals such as
And Ag_FourIn_FourSb₆₆Te₂₆, Ag_FourIn_FourSb₆₄T
e₂₈, Ag_TwoIn₆Sb₆₄Te₂₈, Ag_ThreeIn_FiveSb₆₄Te
₂₈, Ag_TwoIn₆Sb₆₆Te₂₆, Ag-In-Sb-Te
A system in which a metal or semiconductor such as Cu, Fe, Ge or the like is added to the system,
Cu-Al-Sb-Te system, Ag-Al-Sb-Te system
and so on. In addition, porphyrin color
Element, cyanine dye, phthalocyanine dye, naphthalocyanine
Nin dye, azo dye, naphthoquinone dye, fulgide color
Use of nitrogen, polymethine dye, acridine dye, etc.
Can be.

Further, as the recording layer 12, a magneto-optical material that reproduces by changing the Kerr rotation angle can be used.
Specifically, terbium, cobalt, iron, gadolinium,
Alloys of chromium, neodymium, dysprosium, bismuth, palladium, samarium, holmium, proseodymium, manganese, titanium, palladium, erbium, ytterbium, lutetium, tin, etc. (Alloys are oxides, nitrides, carbides, sulfides, fluorides In particular, TbFeCo, GdFeCo, DyF
It is preferable to use a transition metal and a rare earth alloy as typified by eCo. Further, the recording layer 12 may be formed using an alternately laminated film of cobalt and platinum.

Methods of forming these phase change materials, dye materials, and magneto-optical materials include resistance heating type and electron beam type vacuum evaporation, DC sputtering, high frequency sputtering, reactive sputtering, ion beam sputtering, ion plating, and chemical vapor deposition. A layer deposition method (CVD) or the like can be used. Among dye materials, particularly, for a material soluble in a solvent, a liquid layer coating method such as dip coating, spin coating, bar coating, knife coating, and roll coating can be used.

The light transmitting layer 11 has a function of guiding the converged reproduction light to the recording layer 12 with little optical distortion (the reproduction light is indicated by an arrow in FIG. 1). For example, a material having a transmittance of 70% or more, preferably 80% or more at the reproduction wavelength λ can be suitably used. The light-transmitting layer 11 needs to have a small optical anisotropy, and specifically has a birefringence of 90 degrees (perpendicular) in consideration of suppressing a decrease in reproduction light.
± 100 nm or less in incident double pass, preferably ± 5
A material having a thickness of 0 nm or less, more preferably ± 30 nm is used.

Materials having such properties include polycarbonate, polymethyl methacrylate, cellulose triacetate, cellulose diacetate, polystyrene, polycarbonate / polystyrene copolymer, polyvinyl chloride,
Alicyclic polyolefin, polymethylpentene, and the like can be used.

The light transmitting layer 11 may have a function of mechanically and chemically protecting the recording layer 12.
As a material having such a function, a material having high rigidity can be used. For example, a transparent ceramic (for example, soda lime glass, soda aluminosilicate glass, borosilicate glass, quartz glass), a thermosetting resin, or an energy ray curing resin (For example, an ultraviolet curable resin, a visible light curable resin, and an electron beam curable resin) are preferably used. The thickness of the light transmitting layer 11 is desirably 0.120 mm or less from the viewpoint of suppressing coma when the information recording carrier 1 is inclined with respect to the reproduction light / recording light, and also prevents scratches on the recording layer 12. From a viewpoint, 0.07 mm or more is desirable. That is, 0.0
It is in the range of 70 to 0.120 mm. Assuming that the light transmitting layer 11 is made of the above material, the refractive index (z) is 1.4.
Since it is 5 to 1.7, a particularly desirable thickness range is 0.093 to 0.107 mm in consideration of the optical element. Also, the variation in one side of the thickness is up to ±
0.003 mm, preferably ± 0.002 mm or less. More preferably, it is set to ± 0.001 mm or less.

Next, the fine pattern 2 which is a feature of the present invention
0 will be described with reference to FIG. As described above, the fine pattern 20 is composed of a series of grooves that are substantially parallel to each other microscopically. When viewed macroscopically, the fine pattern 20 may be not only linear but also concentric or spiral. Good thing. As shown in FIG. 2, the projections in the fine pattern 20 are the land portions L, and the depressions are the groove portions G, and the land portions L and the groove portions G are alternately formed in parallel.

Here, the groove portion G is an "optical disk understood by this" (edited by the Patent Office, Invention Association 2000).
Year issuance) according to the definition in Table 4.4-1. That is, the groove portion G is a “concave groove that is provided in advance in a spiral or concentric manner in order to form a recording track on the substrate surface” of the disk. The land L also follows the definition in the same book. That is, the land L is
"Protrusions provided in advance in a spiral or concentric manner to form recording tracks on the substrate surface of the disk". Here, the “substrate” corresponds to the support 13 in the present invention.

If the shortest distance between the groove portions G is the pitch P (the shortest distance between the land portions L is also the pitch P), P <S with respect to the reproduction spot diameter S. The relationship is to be fulfilled. Here, the reproduction spot diameter S is calculated from the wavelength λ of the laser beam used for reproduction and the numerical aperture NA of the objective lens as S = λ / NA. In other words, the pitch P satisfies the relationship of P <λ / NA. For example, the pitch P is 25
It is set to 0 to 600 nm. When considering recording HDTV images for about 2 hours, 250-450n
m is desirable. Note that the depth of the groove G is 10 to 30.
0 nm is appropriate, and especially considering the λ of the reproducing optical system,
λ / (8z) to λ / (18z) are preferred. here,
z represents the refractive index of the transmission layer 11 at λ. For example,
λ = 405 nm, z = 1.6 (polycarbonate resin)
When it is assumed, 14 to 32 nm is a range that can be suitably used.

Microscopically, the groove portion G and the groove portion G, the land portion L and the land portion L, and the groove portion G and the land portion L are parallel to each other. May meander. For example, these grooves may be recorded at a single frequency to embed the clock, resulting in a meandering sinusoidal shape on the surface of the support 13. Amplitude modulation (AM) or frequency modulation (F) to embed auxiliary information (sub information) such as an address
M) or phase modulated (PM) and may meander in various patterns. In other words, at least one of the area where the single frequency for clock is recorded and the modulation recording area for embedding the address is formed by the groove G and the land L.
Can be formed beforehand. Modulation for embedding auxiliary information (sub-information) such as addresses will be described later in detail.

When the information recording medium 1 is in the form of a disk, the meandering is caused by a constant angular velocity (constant angular velocity).
(Velocity, CAV), or may be recorded at a constant linear velocity (CLV). Alternatively, different zones are formed for different radii, and ZCAV (zone constant angular) having different control for each zone.
velocity) and ZCLV (zone constant linear velocit)
y) may be adopted.

Although not shown, in order to embed the address, the groove G or the land L may be cut over a certain area to form a unique pit. Alternatively, a unique pit may be arranged in the groove G adjacent to the land L, or a unique pit may be arranged in the land L adjacent to the groove G to embed the address. In addition, a hologram for recognizing the information recording carrier 1 or a fine pattern that can be viewed may be formed in a region other than the recording area.

The information recording carrier 1 receives reproduction light from the light transmitting layer 11 side, reads information recorded on the recording layer 12, reflects the information on the surface of the recording layer 12, and reflects the information on the surface of the recording layer 12. And played back. It should be noted that the information recording carrier 1 can function as it is because the surface of the recording layer 12 itself has a certain degree of reflectance. A reflective layer or a protective film may be provided close to the recording layer 12 for the purpose of providing other functions such as improvement of weather resistance. The materials of the reflective layer and the protective film will be described later in detail.

Here, the cross erase of the information recording medium 1 of the present invention was evaluated in comparison with the conventional information recording medium 100. The configuration of the information recording carriers 1 and 100 is such that the supports 13 and 130 are made of polycarbonate resin, the recording layer 12,
120 is AgInSbTe which is a kind of phase change material, and the light transmitting layers 11 and 110 are polycarbonate resins. After recording and reproducing on the second track, the first track and the third track were evaluated.
Recording was performed 10 times on the track at a frequency different from that of the second track, and the output of the second track was measured again.

As a result, a cross erase of -5 dB at the maximum was observed in the conventional information record carrier 100, and a cross erase of -2 dB was observed in the information record carrier 1 of the present invention.
That is, as compared with the output of the second track when the recording is not performed on the first track and the third track, the output of the conventional information recording carrier 100 is reduced by 5 dB, whereas the output of the information carrier of the present invention is reduced. In No. 1, there was only a 2 dB reduction in output. In other words, when the information recording medium 1 according to the present invention is used, the cross erase is improved by 3 dB as compared with the conventional information recording medium 100.

As described above, according to the first embodiment of the present invention, when the pitch between the grooves G or the lands L is P, the wavelength of the laser beam is λ, and the numerical aperture of the objective lens is NA,
Since the fine pattern 20 is formed so as to satisfy the pitch P <λ / NA and recording is performed on either the land L or the groove G, cross erase can be reduced and high density recording can be performed. An information record carrier is obtained.

Next, an information recording carrier 2 according to a second embodiment of the present invention will be described with reference to FIG. The same components as those in the first embodiment of the present invention are denoted by the same reference numerals, and description thereof will be omitted. As shown in FIG. 3, in the information recording carrier 2 of the second embodiment of the present invention, the light transmitting layer 11 of the first embodiment of the present invention comprises a light transmitting layer 11a and an adhesive light transmitting layer 11b. Other than the above are the same.

The light transmitting layer 11a is the same as the light transmitting layer 11 described above. The adhesive light transmitting layer 11b is a layer for firmly bonding the recording layer 12 and the light transmitting layer 11a, and has a wavelength λ.
, 70% or more, desirably 80% or more, and adhesive thermosetting resin, various energy ray curable resins (including ultraviolet curable resin, visible light curable resin, and electron beam curable resin), moisture curable resin, A multi-liquid mixed cured resin, a solvent-containing thermoplastic resin, or the like can be used. The thickness of the adhesive light-transmitting layer 11b is 0.1 mm as the minimum thickness at which the adhesive force is exerted.
The thickness is preferably 001 mm or more and 0.04 mm or less in consideration of preventing the occurrence of stress cracking of the adhesive resin, and more preferably 0.001 mm or more and 0.03 mm or less. More desirably, it is 0.001 mm or more and 0.02 mm, but considering the warpage of the entire information recording carrier 2, most desirably 0.001 mm or more and 0.01 mm or less. Coating methods include spin coating, spraying, dipping, blade coating, roll coating, knife coating,
A screen printing method, an offset printing method, or the like can be used.

Similar to the first embodiment of the present invention, when the cross erase of the information recording medium 2 of the second embodiment of the present invention was evaluated, similar results were obtained. Therefore, according to the second embodiment of the present invention, the first embodiment of the present invention
The same effect as the embodiment can be obtained.

Next, an information recording carrier 3 according to a third embodiment of the present invention will be described with reference to FIG. The same components as those in the first embodiment of the present invention are denoted by the same reference numerals, and description thereof will be omitted. As shown in FIG. 4, the information recording carrier 3 according to the third embodiment of the present invention comprises a resin layer having a fine pattern 21 formed on the surface of the support 13 of the information recording carrier 1 according to the first embodiment of the present invention. Recording layer 12 sequentially formed on
And the light transmitting layer 11. The third embodiment of the present invention
The fine pattern 2 is formed not on the surface of the support 13 but on the resin layer 14.
1 in that it is different from the first embodiment of the present invention.

The resin layer 14 is made of a thermosetting resin, various energy ray-curable resins (ultraviolet curable resin, visible light curable resin,
An electron beam-curable resin), a moisture-curable resin, a multi-liquid mixed-curable resin, a solvent-containing thermoplastic resin, and the like. Since light does not reach the resin layer 14, there is no limitation on the transmittance. The thickness of the resin layer 14 is desirably 0.02 mm or less in consideration of the warpage of the entire information recording carrier 3.

Similar to the first embodiment of the present invention, when the cross erase of the information recording carrier 3 of the third embodiment of the present invention was evaluated, similar results were obtained. Therefore, according to the third embodiment of the present invention, the first embodiment of the present invention is described.
The same effect as the embodiment can be obtained.

Next, an information recording carrier 4 according to a fourth embodiment of the present invention will be described with reference to FIG. The same components as those in the first embodiment of the present invention are denoted by the same reference numerals, and description thereof will be omitted. As shown in FIG. 5, an information recording carrier 4 according to a fourth embodiment of the present invention includes a pattern transfer layer 15 having a fine pattern 22 sequentially formed on a support 13, a recording layer 12, and an adhesive transparent layer. It comprises a light layer 11b and a light transmitting layer 11a. And the fourth embodiment of the present invention is the
The second embodiment differs from the second embodiment in that the surface is flat and the fine pattern 22 is formed on the pattern transfer layer 15 in contact with the support 13.

Here, the pattern transfer layer 15 is a very thin film for providing the fine pattern 22. The material of the pattern transfer layer 15 is selected from metals and alloys thereof (alloys include examples of oxides, nitrides, carbides, sulfides, and fluorides) and resins.
m to about 0.020 mm is selected. Representative examples of the resin include a novolak photosensitive resin that can be developed with an alkali and a polyhydroxystyrene photosensitive resin that can be developed with an alkali.

Similar to the first embodiment of the present invention, when the cross erase of the information recording carrier 4 of the fourth embodiment of the present invention was evaluated, similar results were obtained. Therefore, according to the fourth embodiment of the present invention, the first embodiment of the present invention is provided.
The same effect as the embodiment can be obtained.

As described below, the components of the information recording carriers 1 to 4 shown in FIGS. 1 to 5 may be replaced or combined with each other as long as the reproduction characteristics are not deteriorated. For example, two information recording carriers 1 to 4 may be prepared, and the supports 13 may be attached to each other so as to face each other. Further, on the light transmitting layers 11 and 11a of the information recording carriers 1 to 4,
The recording layer 12 and the light-transmitting layers 11 and 11a may be stacked one on another. In this way, the capacity of the information recording carriers 1 to 4 can be approximately doubled.

Although not shown, the recording layer 12 of the light transmitting layer 11 is used to reduce the adhesion of dust to the light transmitting layers 11 and 11a.
A known antistatic layer may be formed on the opposite side. The objective lens 50b constituting the pickup 50 of the first reproducing apparatus 40 shown in FIG. On the opposite side, a hard coat layer, a lubricating layer, etc. may be formed (not shown). Specific examples of the material of the hard coat layer include a thermosetting resin that transmits 70% or more of light having a wavelength λ, various energy ray-curable resins (including an ultraviolet-curable resin, a visible light-curable resin, and an electron beam-curable resin), and moisture. A cured resin, a mixed-curing resin of a plurality of liquids, and a thermoplastic resin containing a solvent can be used.

The hard coat layer comprises a light-transmitting layer 11
In consideration of the abrasion resistance of a, it is desirable that the pencil scratch test value of JIS K5400 be a certain value or more. The hardest material of the objective lens 50b is glass,
In consideration of this, the pencil scratch test value of the hard coat layer is particularly preferably H or more. If the value is less than this test value, dust is remarkably generated due to scraping of the hard coat layer, and the error rate is rapidly deteriorated.

The thickness of the hard coat layer is desirably 0.001 mm or more in consideration of impact resistance, and desirably 0.01 mm or less in consideration of warpage of the entire information recording carrier 1. Application methods include spin coating, spraying,
Dipping, blade coating, roll coating, knife coating, screen printing, offset printing, and the like can be used.

As another material of the hard coat layer, a simple substance such as carbon, molybdenum, silicon or the like which transmits at least 70% of light having a wavelength λ and has a pencil scratch test value of H or more, or an alloy thereof (oxide, nitride, sulfide). (Including examples of materials, fluorides and carbides) (film thickness 1 to 1000 n)
m). Examples of the forming method include resistance heating type or electron beam type vacuum deposition, DC sputtering, high frequency sputtering, reactive sputtering, ion beam sputtering, ion plating, and chemical vapor deposition (CV).
D) and the like can be used.

As a specific material of the lubricating layer, a liquid lubricant obtained by modifying a hydrocarbon polymer with silicon or fluorine and adjusting the surface energy can be used. The thickness of the lubricating layer is desirably about 0.1 nm to 10 nm. Application methods include spin coating, spraying,
Dipping, blade coating, roll coating, knife coating, tampo coating, screen printing, offset printing, and the like can be used.

Although not shown, label printing may be performed on the side of the support 13 opposite to the recording layer 12. For example, various energy ray-curable resins (including ultraviolet ray-curable resins, visible light-curable resins, and electron beam-curable resins) containing various pigments and dyes can be suitably used.
mm or more, and the information recording carriers 1, 2, 3,
4 0.05 mm or less is desirable in consideration of the entire warpage.
As a printing method, a screen printing method, an offset printing method, or the like can be used.

Each of the information recording carriers 1 to 4 may have a configuration in which the entire information recording carrier is placed in a cartridge in order to improve the mountability to a reproducing apparatus and the protection in handling. Further, when the information recording carriers 1 to 4 are disk-shaped, their size is not limited, and for example, the diameter is 20 to 40.
It can take various sizes of 0mm, diameter 32, 4
1, 51, 60, 65, 80, 88, 120, 130,
It may be 200, 300, 356 mm or the like.

The recording layer 12 may be made of a plurality of thin film materials for the purpose of improving recording characteristics and reproduction characteristics, and will be described in detail with reference to the following embodiments. An information recording carrier 5 according to a fifth embodiment of the present invention in which the recording layer 12 of the information recording carrier 1 has four thin film materials will be described with reference to FIG. The same components as those in the first embodiment of the present invention are denoted by the same reference numerals, and description thereof will be omitted. As shown in FIG.
The information record carrier 5 of the fifth embodiment of the present invention is different from the information record carrier 1 of the first embodiment of the present invention in that
A reflective layer 121, a first protective layer 122, and a recording layer 12 sequentially formed on a support 13 having a fine pattern 20;
3, the second protective layer 124, and the light transmitting layer 11.

As a material of the reflective layer 121, a metal such as Al, Au, or Ag having light reflectivity, an alloy containing these as a main component and containing one or more kinds of metal or an additive element composed of a semiconductor, or Al, Au , Ag, or the like, and a metal compound such as a metal nitride, a metal oxide, or a metal chalcogenide. Metals such as Al, Au, and Ag, and alloys containing these as main components are preferable because of high light reflectivity and high thermal conductivity. In addition, since the reflection layer 121 also has a role of optimizing heat conduction when performing recording on the recording layer 123, it may be called a heat sink layer.

For the above alloys, Al, Ag and Si, Mg, Cu, Pd, T
i, Cr, Hf, Ta, Nb, Mn, Pd, Zr, Rh
5 at% or less in total with at least one element such as
1 atomic% or more, or Au to which at least one element such as Cr, Ag, Cu, Pd, Pt, or Ni is added as an additional element in a total amount of 20 atomic% or less and 1 atomic% or more and so on. In particular, Al-Cr alloys, Al-Ti alloys containing Al as a main component and having a total of 0.5 to less than 3 atomic% as a total of additional elements because of good corrosion resistance and improved repetition performance. Al-Ta
Alloy, Al-Zr alloy, Al-Ti-Cr alloy, Al-
It is preferable to be composed of any of the Si-Mn alloys.

As the additive element, it is preferable to add a metal or a semiconductor rather than a simple metal, because the crystal grains become small and the noise level at the time of reproduction decreases. Further, in order to improve the stability under high temperature and high humidity, it is better to include an additive. For example, Al-Ti, Al-Cr, Al
-Zr, Al-Si, Ag-Pd-Cu, Ag-Rh-
Alloys such as Cu can be used. When a blue semiconductor laser having a wavelength of about 400 nm is used, higher reflectance can be obtained by using an Al-based or Ag-based alloy. The thickness of these reflective layers 121 is 10 nm or more and 300 nm or less.

This film thickness changes depending on the magnitude of the thermal conductivity of the metal or alloy forming the reflection layer 121. For example, in the case of an Al—Cr alloy, the thermal conductivity decreases as the Cr content increases, so that it is not suitable for a recording strategy unless the thickness of the reflective layer 121 is increased. C
When the r content is large, the recording layer 123 is easily heated and hardly cooled, and has a so-called slow cooling structure. In order to control the formation of the recording mark by the recording strategy, it is necessary to devise a technique such as shortening the leading pulse, shortening the multi-pulse, or extending the cooling pulse.

When the thickness of the reflective layer 121 is 50 nm or more, it does not change optically and does not affect the value of the reflectivity, but greatly affects the cooling rate. The thickness is 300
Since it takes time in manufacturing to make the thickness not less than nm, the film thickness is suppressed as much as possible by using the reflective layer 121 made of a material having high thermal conductivity.

When the reflection layer 121 is divided into two or more layers, the noise level when the information recording carrier 5 is reproduced can be reduced. The reflection layer 121 is formed, for example, as follows. Using a single-wafer sputtering apparatus that transports the support 13 one by one and deposits each layer in a plurality of vacuum chambers,
When forming the reflective layer 121 having a total thickness of 150 nm, the first reflective layer is formed in the first vacuum chamber at a deposition rate of 2 nm / s.
If the second and third reflective layers are formed at a film formation rate of 6.5 nm / s in the second and third vacuum chambers, disks can be formed one after another in a short time of 10 seconds. Can be. As described above, since the crystal grains can be made finer by changing the film forming rate, it is possible to reduce the noise level when the information recording carrier 5 is reproduced.

First protective layer 122 and second protective layer 124
The signal at the time of reproduction is obtained by an effect of protecting the support 13 and the recording layer 123 from heat and an optical interference effect, such as preventing the substrate, the recording layer, and the like from being deformed by heat during recording and deteriorating the recording characteristics. This has the effect of improving contrast. These protective layers 122 and 124 are transparent at the wavelength of the recording / reproducing light and have a refractive index n of 1.9 ≦ n ≦.
It is in the range of 2.5.

The first protective layer 122 and the second protective layer 124 do not have to be made of the same material and composition, and may be made of different materials. The thickness of the second protective layer 122 determines a wavelength at which the spectral reflectance has a minimum value. Further, the first protective layer 122 and the second protective layer 124 also have the effect of promoting crystallization of the recording layer and improving the erasing rate. As a material of these protective layers 122 and 124, ZnS, SiO
_2. There are inorganic thin films such as silicon nitride and aluminum oxide.

In particular, Si, Ge, Al, Ti, Zr, T
a or a thin film of a metal or semiconductor oxide, Si, G
e, thin film of nitride of metal or semiconductor such as Al, T
Carbonization of metal or semiconductor such as i, Zr, Hf, Si
Thin film, ZnS, In_TwoS _Three, TaS_Four, GeS_TwoEtc.
Thin films of metal or semiconductor sulfides and their compounds
A film of a mixture of two or more types of materials has high heat resistance and
It is preferable because it is stable.

Further, it is preferable that the material of the protective layers 122 and 124 does not diffuse into the recording layer 121. These oxides, sulfides, nitrides, and carbides do not necessarily need to have a stoichiometric composition, and it is effective to control the composition for controlling the refractive index and the like, or to use a mixture thereof. The refractive index n is controlled by changing the contents of oxygen, sulfur, nitrogen and carbon. As these contents increase, the refractive index decreases.

In particular, a mixed film of ZnS and SiO ₂ is preferable because deterioration of recording sensitivity, C / N, erasing rate, etc. hardly occurs even when recording and erasing are repeated.
The thickness of each of the first protective layer 122 and the second protective layer 124 is approximately 10 to 500 nm. First protective layer 122
Is preferably 10 to 50 nm because recording characteristics such as C / N and erasing rate and stable rewriting can be performed many times.

If the thickness of the first protective layer 122 is small, the reflectivity increases and the recording sensitivity decreases. In addition, a large recording power is required to form a mark due to a narrow space between the reflective layer 121 and the rapid cooling structure. Conversely, the first protective layer 12
When the thickness of No. 2 is increased, the distance between the reflective layer 121 and the reflective layer 121 is widened, and a slow cooling structure is formed, whereby the rewriting performance is deteriorated and the number of repetitive overwriting is reduced.

The thickness of the first protective layer 122 is
It is thinner than 24 and has a so-called quenching structure, and the film thickness is preferably 2 to 50 nm in order to reduce thermal damage. Preferably, the deposition rate of the first protective layer 122 is lower than the deposition rate of the second protective layer 124. This suppresses an increase in jitter due to rewriting and increases the number of rewriting.

The material of the recording layer 123 is the same as that of the recording layer 1 described above.
2, the same phase change material can be used. The thickness of the recording layer is 5 to 100 nm, preferably 10 to 30 nm in order to increase the reproduction signal. The same material as the first protective layer 122 is used for the second protective layer 124.
The thickness of the second protective layer 124 is in the range of 10 to 200 nm. The optimum film thickness varies depending on the wavelength of the light source to be used, but it is preferable to use 40 to
The thickness is preferably 150 nm. If the recording laser beam is blue-violet (wavelength: about 400 nm), the modulation amplitude can be increased by setting it to 40 to 60 nm.

As described above, according to the fifth embodiment of the present invention, in addition to the effects of the first to fourth embodiments of the present invention, the recording characteristics and the reproduction characteristics of the information recording carrier 5 can be improved. . Note that these laminated structures may be applied to the information recording carriers 2 to 4 as well as the information recording carrier 1. Further, in order to further improve the recording characteristics and the reproduction characteristics, a further auxiliary thin film may be formed on each layer or between layers. As described above, since the information recording carriers 1 to 5 of the first to fifth embodiments of the present invention are recorded on either the groove G or the land L, cross erase can be reduced.

Further, from the viewpoint of signal quality, it was examined whether the information recording carrier 5 according to the present invention should be recorded on the groove G or the land L, and it was found that recording on the land L had a lower error rate. It was also found that the rewriting characteristics were excellent. This means that considering that the land L is closer to the light transmitting layer 11 than the groove G, and that the reproduction light is incident from the light transmitting layer 11 side, the land L region easily accumulates heat in the material, This is considered to be due not only to high sensitivity, but also to the property of enabling ideal recording with a uniform shape of the recording mark. (On the other hand, when recording is performed on the groove G, it is considered that ideal recording cannot be performed because heat is easily dissipated.)

Next, with respect to the information recording carrier of the present invention,
Analog or digital assistance such as address data
Modulation pattern for embedding information (sub-information)
It will be described in detail. The auxiliary information (sub-information) is
Width modulation (AM) or frequency modulation (FM) or phase modulation
Shape recording as meandering pattern by key (PM)
Is done. In other words, as a meandering pattern,
(Recorded as a groove on the support 13 or the light transmitting layer 11)
Recorded), so even permanent information that cannot be rewritten
You. When the information recording carrier 1 is in a disk shape,
Since the tangentially extending groove is recorded in a meandering manner,
The row direction is the radial direction.

The address data in the auxiliary information (sub-information) to be recorded in the present invention includes an absolute address assigned to the entire surface of the information recording medium 1, a relative address assigned to a partial area, a track number, and a sector. Number, frame number, field number, time information, error correction code, etc.
This is data converted from binary notation or hexadecimal notation into binary (including examples of BCD codes and Gray codes).

It is to be noted that auxiliary information other than address data can be handled. For example, the type of information record carrier, the size of the information record carrier, the assumed recording capacity of the information record carrier, the assumed recording linear density of the information record carrier, the information record carrier Assumed recording linear velocity,
Track pitch of information record carrier, recording strategy information,
Playback power information, manufacturer information, serial number, lot number,
At least one of the following: management number, copyright-related information, encryption key, decryption key, encrypted data, recording permission code, recording rejection code, reproduction permission code, reproduction rejection code, etc. Code data may be mentioned, and may be accompanied by an error correction code for these data.

In the following description, it is assumed that the auxiliary information (sub-information) is an address for simplification. FIG.
Is an address 250 recorded by amplitude modulation (AM).
The address 250 is a groove portion G or a land portion L constituting the fine pattern 20.
The shape is partially or entirely recorded in any of the above. In amplitude modulation (AM), data "1" or data "0" is recorded depending on the presence or absence of amplitude. In the example of FIG. 11, data “1” is recorded as an amplitude portion 251 and data “0” is recorded as an amplitudeless portion 252.

As an example of address data, 101
In the case of recording 10, as shown in FIG. 7, the shape is recorded in the order of the amplitude portion 251, the amplitudeless portion 252, the amplitude portion 251, the amplitude portion 251, and the amplitudeless portion 252. Such a method of recording data based on the presence or absence of amplitude has an advantage that demodulation can be performed even in a low C / N environment because of a simple signal format. In particular, in the information recording carrier 1 according to the present invention in which the influence of crosstalk from an adjacent track can be minimized and the track pitch P is shorter than the reproduction spot diameter S, this is an effective address recording method.

Here, the amplitude portion 251 and the amplitudeless portion 251
The length of 52 may be the same or different,
To optimize the demodulation error rate, it is desirable that the lengths be the same. The number of waves constituting the amplitude portion 251 is arbitrary, but is plural in order to prevent a reading error, and a non-redundant number is appropriate so as not to lower the recording density of address recording. From such a viewpoint, the number of waves is preferably about 2 to 10. The amplitude widths of the amplitude portions 251 may be different from each other, but are preferably the same in consideration of ease of setting a slice level at the time of demodulation.

When an area in which a single frequency for clock is recorded is provided separately from the address 250, the single frequency and the frequency of the amplitude portion 251 may be different or the same. However, if they are the same,
Since the physical length used for extracting the clock can be slightly increased, the stable extraction of the clock is facilitated, which is advantageous.

FIG. 8 is an enlarged view of an address 300 recorded by frequency modulation (FM).
The shape of the address 300 is partly or entirely recorded in either the groove portion G or the land portion L constituting the fine pattern 20. In frequency modulation (FM),
Data "1" or data "0" depending on the frequency
Is recorded. In the example of FIG. 8, data “1” is recorded as a high frequency portion 301 and data “0” is recorded as a low frequency portion 302. And as an example of address data, 1
In the case of recording 0110, as shown in FIG. 8, the shape is recorded in the order of the high frequency portion 301, the low frequency portion 302, the high frequency portion 301, the high frequency portion 301, and the low frequency portion 302.

The method of recording data according to the frequency level has the advantage that demodulation can be performed with a simple circuit configuration. In particular, as shown in FIG. 8, when the phase is selected so that the waves are continuous at the switching point of the frequency, the reproduction envelope becomes substantially constant, and stable address extraction can be realized. Here, the lengths of the high-frequency portion 301 and the low-frequency portion 302 may be the same or different. desirable.

The number of waves constituting the high frequency part 301 and the low frequency part 302 is arbitrary. The amplitude widths of the high frequency portion 301 and the low frequency portion 302 may be different from each other, but are desirably the same in consideration of ease of demodulation. The selection of the frequencies of the high frequency part 301 and the low frequency part 302 is arbitrary,
It is desirable to set the phase difference between the two frequencies to be ± π / 12 to ± π / 0.75. In particular, as shown in the drawing example of FIG. 8, the frequency ratio (high frequency / low frequency) is 1.
Assuming a factor of 5, the two frequencies have a single wave phase of -π /
The relationship is shifted to 2.5 and + π / 2.5. These two
One frequency can be represented by an integral multiple (here, three and two times) of a single frequency (here, 0.5). Therefore, there is an advantage that the demodulation circuit can be simplified. In addition, demodulation can be performed by synchronous detection, and the error rate can be significantly reduced.

As another example, the frequency ratio (high frequency /
If the low frequency is 1.28 times, the two frequencies have a relationship in which the phase of a single wave is shifted to −π / 4 and + π / 4.
Therefore, also in this case, demodulation can be performed by synchronous detection, and the error rate can be significantly reduced.

When an area in which a single frequency for a clock is recorded is provided separately from the address 300, the single frequency, the high frequency part 301 and the low frequency part 302 are provided.
May be different from each other. However, if one of the high frequency part 301 and the low frequency part 302 and the single frequency in the clock domain are the same, the physical length used for clock extraction can be slightly increased, so that the clock can be stably extracted. It is easier and more advantageous.

FIG. 9 is an enlarged view of a first phase modulation address 400 recorded by phase modulation (PM). G or land L
The shape is partially or entirely recorded in any of the above. In the phase modulation (PM), data “1” or data “0” is recorded depending on the phase difference. In the example of FIG. 9, data “1” is recorded as a sin0 portion 401 and data “0” is recorded as a sinπ portion 402. When 10110 is recorded as an example of the address data, as shown in FIG.
The shape is recorded in the order of a sinπ portion 402, a sin0 portion 401, a sin0 portion 401, and a sinπ portion 402.

The method of recording data based on the difference in phase as described above has an advantage that the data can be reproduced even in a low C / N environment by demodulation by synchronous detection. Here, the length of the sin0 portion 401 and the length of the sinπ portion 402 may be the same or different. . Also, sin0 part 401 and si
The amplitude widths of the nπ portions 402 may be different from each other, but are desirably the same in consideration of ease of demodulation. In addition, two phase differences are set to π, and binary recording of 0 and π is performed. However, the present invention is not limited to this. For example, the phase difference is set to π / 2, and -3π / 4, -π / 4, + π / 4, + 3π / 4
Quaternary recording.

When a region for recording a single frequency for a clock is provided separately from the first phase modulation address 400, even if the single frequency and the frequency of the sin0 portion 401 or the sinπ portion 402 are different from each other. Good.
However, if they match, the physical length used for clock extraction can be slightly increased, so that stable extraction of the clock is facilitated and advantageous.

The first phase modulation address 400
However, a single clock frequency may be superimposed and recorded. That is, the phase modulation address is multiplied by an integer (1).
Or a frequency that is a fraction of an integer. When the clock frequency is superimposed as described above, the frequency can be separated by a known band-pass filter, but it is preferable that the difference between the first phase modulation address 400 and the clock frequency is large. For example, if the frequency of the first phase modulation address 400 is 1 and the frequency of the clock is １ ／, these frequencies are suitably separated, and stable extraction of both the address and the clock becomes possible.

FIG. 10 is an enlarged view of the second phase modulation address 450 recorded by the phase modulation (PM). The shape is formed in either the groove portion G or the land portion L constituting the fine pattern 20. Has been recorded. In this example, the wave is regarded as an asymmetrical shape of rising and falling, and the phase difference is expressed by controlling each of them separately. That is, in the example of FIG.
(Hereinafter referred to as a steep falling part 451), data "0" is a steep rising and a gentle falling part 452 (hereinafter, referred to as a steep falling part).
(Referred to as a steep climb portion 452).

Then, as an example of address data, 101
In the case of recording 10, as shown in FIG.
The shape is recorded in the descending steep part 451, the ascending steep part 452, the descending steep part 451, the descending steep part 451, and the ascending steep part 452 in this order. The method of recording data based on the phase difference as described above has an advantage that demodulation can be performed by inputting the data to a high-band filter and extracting a differential component, and reproduction can be performed even in a low C / N environment. Here, the steep descent part 45
1. The length of the steeply rising portion 452 may be the same or different, but it is desirable that the lengths be the same in order to optimize the demodulation error rate.

A steep descent portion 451 and an ascending steep portion 452
May be different from each other, but are desirably the same in consideration of ease of demodulation. Also,
When an area in which a single frequency for a clock is recorded is provided separately from the second phase modulation address 450, the single frequency may be different from the frequency of the steep falling part 451 or the steep rising part 452. . However, when they match, the physical length used for extracting the clock can be slightly increased, so that the stable extraction of the clock is facilitated, which is advantageous.

In the above description, the amplitude modulation (A
M), frequency modulation (FM), and phase modulation (PM) have been described by using a method of directly recording address data as a meandering groove. And
The fundamental wave of the groove meandering is assumed to have a sin shape, but the present invention is not limited to this. For example, it is needless to say that the same effect can be obtained even when the fundamental wave of the groove meandering is formed into a cos shape.

Address data may be multiplex-recorded by a different method or may be time-division-recorded. For example, A
Different methods such as M + FM, AM + PM, and FM + PM may be combined and recorded. Also, for example, time-division recording with AM for a certain time and FM for another certain time, or time-division recording with AM for a certain time and PM for another certain time, or FM for another certain time, Time-division recording may be performed with a certain period of time as PM. Also, as mentioned above,
In addition to this, time-division recording in which a single frequency region for extracting a clock is recorded at different fixed times may be used.

By the way, regarding the meandering width of the groove, the amplitude due to the meandering can be satisfactorily reproduced by setting the value to be equal to or less than the pitch P. Specifically, by setting the amplitude due to the meandering to be equal to or less than the pitch P, an address that does not physically contact an adjacent track can be recorded, so that crosstalk due to recording can be avoided. In addition, when random data is written by phase change recording in a groove in which an address is recorded with the meandering amplitude being equal to or less than the pitch P and address reproduction is attempted by a push-pull method, the limit of address signal detection is as follows. The meandering amplitude (peak to peak) is 2% or more of the reproduction spot diameter S, and in a groove formed below this, random data by phase change recording is remarkably superimposed as noise, resulting in an address error. The rate has soared.

On the other hand, the meandering amplitude is 9% of the reproduction spot diameter S.
In the case described above, the crosstalk of the adjacent track was remarkably superimposed on the push-pull signal, and the address error rate increased rapidly. Therefore, the meandering amplitude must be equal to or less than the pitch P, and the range of 2 to 9% of the reproduction spot diameter S is most suitable.

The present invention is not limited to this direct recording.
That is, in the direct recording, when recording a long address data string, 0s may be continuous or 1s may be continuous, and a DC component may be generated in the data. In order to avoid this, a method of recording data by baseband modulation in advance may be adopted. In other words, 0 and 1 are replaced in advance with another code, and the continuation of 0 and 1 is reduced to a certain value or less. Such methods include Manchester codes,
PE modulation, MFM modulation, M2 modulation, NRZI modulation, NR
Z modulation, RZ modulation, differential modulation and the like can be used alone or in combination.

As a method of baseband modulation particularly suitable for the information recording medium 1 according to the present invention, there is a Manchester code (bi-phase modulation, two-phase modulation). This is for one bit of data to be recorded, as shown in FIG.
This is a method of applying 2 bits. That is, 00 or 11 is assigned to data 0 to be recorded, and 01 or 10 is assigned to data 1. When connecting data, the data must always be entered from the reverse sign of the previous sign.

As shown in FIG. 12, the address data of 100001 becomes a code string of 001010101011. The original address data is asymmetric data that includes four consecutive 0s and the appearance probability of 0 is twice as large as 1. On the other hand, when the modulation is performed, a maximum of two consecutive 0s or 1s is required, and the occurrence probability of 0s and 1s is converted to symmetrical data having the same appearance probability. Since the baseband modulation in which the continuation of the same bit is limited to a certain value or less has an effect of improving the reading stability, it is a suitable preprocessing when handling long address data.

Further, the address data is highly decomposed,
There is also a distributed recording method. For example, dummy data "10"
This is a recording method in which data is recorded in a combination of data “10X” (X is 0 or 1) and this data string is arranged at regular intervals. If only X is extracted using “10” as a data trigger, data can be restored. This method is effective in a format in which a data string to be handled can be read over time.

As another example of the distributed recording, a first specific data pattern (for example, “101”) which is easy to read is arranged (recorded) at regular intervals. Then, the second specific data pattern that is easy to read (for example, “111”)
1 ") are arranged between the first specific data patterns.
The position at which the second specific data pattern is arranged is a position that is advanced by a predetermined distance (time) with respect to the first specific data pattern. Record as

In reading, the presence or absence of the second specific data pattern can be read by focusing on a predetermined position. This makes it possible to read the recorded address data. Also the second
Of the specific data pattern is prepared in advance as a position that is two types of predetermined distances (time) ahead of the first specific data pattern, and which of the positions is where the second specific pattern is located By the data 1,
Data 0 may be recorded.

In the above description, the distributed recording method using the distance difference between the first specific data pattern and the second specific data pattern has been described. Can be prepared, the first specific data pattern and the second specific data pattern may be the same. Data 1 and data 0 may be specified by extracting a specific pattern shorter than the specific data pattern recorded at a fixed time interval and measuring the specific time interval.

The recording of auxiliary information (address information and other specific code data) by meandering the groove has been described above. Note that, again, the recording described here is not the recording on the recording layer 12, but the shape recording by the meandering of the groove (groove portion G or land portion L). The shape record of the auxiliary information and the clock information (clock extraction single frequency) by meandering the groove is permanent information, and cannot be modified and has high confidentiality. Such recording can be performed with a shape change by using a method of molding the support 13 or the light transmitting layer 11. Here, a stamper recorded with groove meandering is used for molding, but the stamper itself can be manufactured by a so-called mastering method of forming a meandering pattern using energy rays.

As described above, recording on the recording layer 12 (for example, phase change recording) is also performed on the groove portion G or the land portion L. At the time of recording on the recording layer 12, the recording is performed while referring to the auxiliary information and the clock information by the meandering groove (for example, recording is performed while reading the address). Must match. For example, when the track to be recorded is the land L, the track on which the auxiliary information and the clock information have been recorded must also be the land L. If this is different, although recording on the recording layer 12 can be performed physically without any problem, auxiliary information and clock information will be extracted by mixing information of two adjacent tracks by 50% each. Information and clock information cannot be extracted.

For example, when a track to be recorded is a land L and a track on which auxiliary information and clock information are recorded is a groove G, recording on the recording layer 12 in the land L itself is performed. However, if it is attempted to extract auxiliary information such as an address or clock information during recording, information of two adjacent groove portions G with the land portion L interposed therebetween is read. Auxiliary information and clock information are mixed and taken out by 50%.

The two pieces of mixed information cannot be separated, so that recording on the intended track cannot be performed. Therefore, the track to be used for recording,
It is necessary to match the track on which auxiliary information and clock information are recorded in shape. As described above, the recording on the recording layer 12 is particularly preferably performed on the land portion L from the viewpoint of reducing the error rate. Therefore, it is most preferable that the track to be used for recording is the land L, and the track on which auxiliary information and clock information are recorded in the form of a groove is the land L.

Next, a first reproducing apparatus 40 for reproducing the information recording carriers 1 to 5 will be described with reference to FIG. Here, the information record carrier 1 is used for simplifying the description, but the same applies to other information record carriers (information record carriers 2, 3, 4, and 5). As shown in FIG. 13, the first reproducing apparatus 40 controls a pickup 50 for reading reflected light from the information recording carrier 1, a motor 51 for rotating the information recording carrier 1, and driving of the pickup 50 and the motor 51. Servo 52 and pickup 5
0, a demodulator 54 for demodulating the information signal read at 0, an interface (I / F) 55 for transmitting the signal demodulated by the demodulator 54 to the outside, and a controller 60 for controlling the whole.
And at least. Here, the demodulator 54 is, for example, a digital converter that performs an operation of returning 16-bit data to original 8-bit data in the case of 8/16 modulation (EFM plus) used in DVD.

Although the turntable 53 and the information recording carrier 1 are connected to each other with the center hole Q being filled, they may be fixed connections or semi-fixed connections that can be freely attached and detached. The information recording carrier 1 may be mounted on a cartridge, and a known cartridge having an opening and closing mechanism in the center can be used as it is.

The motor 51 is connected to a turntable 53, and the turntable 53 and the information recording carrier 1 are connected to each other by inserting a center hole Q therebetween. The motor 51 holds the information record carrier 1 via a turntable 53 and gives relative movement for reproduction. The signal output may be connected to an external output terminal (not shown), or may be directly connected to a display device, audio device, or printing device (not shown).

The pickup 50 is λ = 350-450
a light emitting element 50a emitting at a single wavelength between 400 nm and 435 nm, preferably an objective lens 50b having a numerical aperture of 0.75 to 0.9, and reflection from the information recording medium 1. An unillustrated photodetector (photodetector) for receiving light is provided. The reproduction light 70 is formed by these. Light emitting element 5 described above
Oa may be a gallium nitride-based compound semiconductor laser or a laser having a second harmonic generation element. The number of the servos 52 is one in the description of the drawings, but may be divided into two, that is, a servo for drive control of the pickup 50 and a servo for drive control of the motor 51.

The demodulator 54 may include a well-known equalizer (not shown) and a PRML decoding circuit. For example, as an equalizer (waveform equalizer), a plurality of conversion systems having non-linear input / output characteristics are connected with independent variable weights to form a neural network. A so-called neural network equalizer (Japanese Patent No. 2797035)
A so-called limit equalizer (Japanese Patent Laid-Open No. 11-259985) that limits the amplitude level of a reproduced signal to a predetermined value and performs a filtering process, finds an error between the reproduced signal and a waveform equalization target value, and minimizes the error. A so-called error-selective equalizer (described in JP-A-2001-110146), which adaptively changes the frequency of the waveform equalizer as described above, can be used particularly preferably.

Also, among the known PRML decoding circuits, a prediction value control / equalization error calculation circuit is included to calculate a prediction value used for decoding the Viterbi algorithm, and to minimize the equalization error of the waveform equalizer. A so-called adaptive Viterbi decoder that optimizes frequency characteristics to perform
00-228064 and JP-A-2001-186
027) can be particularly preferably used.

Next, the operation of the first reproducing apparatus 40 will be described. The reproduction light 70 is emitted from the light emitting element 50 a of the pickup 50, and the fine pattern 20 of the information recording carrier 1 is
To collect light. Specifically, the fine pattern 20 having a depth of 0.07 to 0.12 mm corresponding to the thickness of the light transmitting layer 11
Focus on Then, groove part G, land part L
Tracking is performed on any one of the. Although this tracking is performed by selecting a predetermined side, it is best to select the land portion L as described above. Then, the reflected light from the fine pattern 20 is received by a photodetector (not shown) and the recording signal is read. Here, the photodetector is 4
The sum signal (so-called Ia + Ib + Ic + Id) of all divided detector outputs is output to the demodulator 5.
4 Here, Ia, Ib, Ic, Id are J
It corresponds to the output of the photodetector divided into four in the DVD defined in IS standard X6241: 1997.
The reading of the recording signal is performed by reproducing the recording mark M recorded in the groove portion G or the land portion L on the fine pattern 20.

Although the description has been omitted, it is necessary to generate a focus error signal for focusing and a tracking error signal for tracking. The focus error signal and the tracking error signal are a difference signal (so-called (Ia + Ib) −) of the output of the quadrant photodetector in the radial direction.
(Ic + Id)) and sent to the servo 52. Then, under the control of the controller 60, a focus servo signal and a tracking servo signal are generated in the servo 52 from the received focus error signal and tracking error signal, and are sent to the pickup 50. On the other hand, a rotation servo signal is also generated from the servo 52 and sent to the motor 51. Then, the demodulator 54 demodulates the above-described recording signal, performs error correction as necessary, and converts the obtained data stream into an interface (I / F) 55.
Send to Then, under the control of the controller 60, the signal is sent out.

As described above, the reproduction apparatus 4 of the present invention
According to No. 0, the information recording carriers 1 are mounted, which are generated by a light emitting element 50a having a single wavelength between λ = 350-450 nm and an objective lens 50b having a numerical aperture NA of 0.75-0.9. Since the information recording medium 1 is designed in conformity with the reproduction light 70 to be reproduced, the information recording medium 1 can be reproduced favorably.

Here, the light emitting element 5 used in the reproducing device 40
Regarding Oa, the light emitting element 50a may be a gallium nitride based compound semiconductor laser or a laser having a second harmonic generation element. However, these two different lasers have their own unique laser noise, and in particular, the gallium nitride-based compound semiconductor laser is characterized by a high noise level. In our measurement, a laser RIN (Relative Intensity) having a second harmonic generation element was used.
Noise) is -134 dB / Hz, which is D
Red semiconductor laser (λ = about 650n) used in VD
m) has almost the same noise.

On the other hand, in the case of the gallium nitride based compound semiconductor laser, RIN is -125 dB / Hz, which is 9 times smaller than that of the laser RIN having the second harmonic generation element.
The dB is also large. This noise is added to the reproduced signal from the information recording carrier 1 as it is, and significantly degrades the S / N of the reproduced signal. That is, when a gallium nitride-based compound semiconductor laser is used for the light emitting element 50a of the reproducing device 40,
Since the signal characteristics are deteriorated, it means that the design guideline obtained with the DVD cannot be adapted by being shifted proportionally. Therefore,
In the case of such a reproducing apparatus 40, an information recording carrier having a signal characteristic that compensates for the deterioration is prepared in consideration of the fact that the laser-specific noise is added to the reproduction signal from the information recording carrier 1. There is a need to.

Next, various productions of the information recording carrier 5 according to the fifth embodiment of the present invention are performed while changing the depth of the fine pattern 20 formed on the support 13 (the difference between the height of the groove G and the height of the land L). A gallium nitride based compound semiconductor laser (RIN: -125 dB / Hz) is used for the light emitting element 50a.
The reproduction was performed by the reproducing apparatus 40 adopting the above, and the relationship between the reflectance and the error rate of the reproduced signal was examined. Note that recording was performed under ideal recording conditions where the error rate was the lowest.

The reflectivity can be said to be the output of a reproduction signal, and in the case of a phase change recording material, is an index correlated with the brightness of the crystal state. Specifically, a modulation signal called a so-called (d, k) code is recorded on the information recording carrier 5.
The recording device will be described later.

The (d, k) modulated signal can be used as a fixed-length code or a variable-length code. 1.
7) Modulation, fixed-length code (1.9) modulation, variable-length code (2.7) modulation, and variable-length code (1.7) modulation can be suitably used. As a typical example of (2.10) modulation of a fixed-length code, 8/15 modulation (Japanese Unexamined Patent Application Publication No. 2000-286)
709), 8/16 modulation (EFM plus),
8/17 modulation (EFM). A typical example of the fixed-length code (1,7) modulation is D1,7 modulation (described in Japanese Patent Application No. 2001-80205). A typical example of the fixed-length code (1.9) modulation includes D4, 6 modulation (described in Japanese Patent Application No. 2000-80205). A typical example of the (1.7) modulation of the variable length code is 17
PP modulation (described in JP-A-11-346154).

[0115] The reflectivity is recorded on the information recording carrier 5 by the reproducing apparatus 40.
Was mounted flat (zero inclination) to reproduce the recorded signal, the DC-system reproduced signal output from the pickup 50 was connected to an oscilloscope, and the signal was obtained from the longest signal used for the code. For example, in the case of 8/16 modulation used in a DVD, the maximum length is 14T, and therefore, as defined in the standard (JIS standard X6241: 1997), I1
4H is measured, and the reflectance is calculated from the absolute reflectance calibration calibration curve. The error rate was obtained by measuring a reproduced signal obtained through the demodulator 54. FIG. 14 shows the result.

As shown in FIG. 14, there is a clear correlation between the reflectance and the error rate, and it can be seen that the error rate increases significantly as the reflectance decreases. If the practical error rate is set to 3 × 10 ⁻⁴ determined by a DVD or the like, the required reflectance is 2% or more. Further, the information recording carrier 5 may warp due to a change in temperature of the use environment or the like.
Therefore, assuming that a tilt of about 0.7 degree can occur as in DVD, λ = 350 to 450 nm, NA = 0.75
The error rate is increased by coma caused by the combination of 0.9 through 0.9 and the thickness of the light transmitting layer 11 of 0.07 through 0.12 mm.

The error rate at the time of adding a 0.7 degree inclination is 3 ×
^10-4 and become the be equivalent to 0.7 × 10 ^-4 at slope zero was found from the measurement result. That is, an error rate of 0.7 × 10 ⁻⁴ is required in consideration of the inclination in actual use. From this, it was found that the practical reflectivity was 5% or more.

As described above, considering that noise is added to the reproduction signal when the gallium nitride compound semiconductor laser is used as the light emitting element, the reflectivity of the information recording carrier 5 is set to 5% or more. If configured, the error rate is D
It is practical to make it about VD specification. FIG.
As a result of experiments, it is known that the correlation between the reflectance and the error rate as described above can obtain substantially the same result using any of the above-described modulation methods.

The longest mark length can vary depending on the modulation method. However, in these modulation methods, the signal output becomes almost saturated and takes a constant value when the length exceeds about 6T. Therefore, for example, recording is performed on the information recording carrier 1 with 17PP modulation, and the obtained reflectance is recorded with 8/16 modulation, and the same value is obtained as the obtained reflectance.

As described above, the information recording carrier 1 according to the present invention having a reflectance of 5% or more in consideration of the reproduction characteristics of the information recording carrier.
5 have been described. Next, the general characteristics of a recording device and a reproducing device using a gallium nitride-based compound semiconductor laser as a light emitting element and the physical characteristics when a phase change material is used for the recording layers 12 and 123 are comprehensively considered. A more practical range of reflectivity necessary for realizing the total system will be described.

The gallium nitride based compound semiconductor laser has a maximum output of 30 mW. In the recording device, λ = 35
Generally, the output is reduced by about one fifth from the coupling efficiency of the optical element used for the wavelength of 0 to 450 nm.
In other words, even when a 30 mW laser is used, the power is 6 mW on the surfaces of the information recording carriers 1 to 5. On the other hand, it is desirable to set the recording power as high as possible in order to realize phase change recording with good contrast. Therefore, it is necessary that the information recording carriers 1 to 5 can record at a recording power of about 6 mW. For that purpose, the absorption and transmittance of the recording layers 12 and 123 of the information recording carriers 1 to 5 need to be high to some extent.

Although the noise of the gallium nitride based compound semiconductor laser and the increase in the noise of the reproducing apparatus using the same have been described so far, it is necessary to keep in mind that the overall system design depends on the reproducing power. No.
The inventors of the present invention measured laser noise while changing the reproducing power. As for the gallium nitride compound semiconductor laser, the lower the laser power, the more the noise, and the critical point was 0.35 mW especially for the reproducing power on the board. I understood. That is, when the power falls below 0.35 mW, the noise increases remarkably. Therefore, the reproducing power of the information recording carriers 1 to 5 needs to be 0.35 mW or more.

As a physical characteristic of the recording layers 12 and 123, when the reproducing power is increased, there is a phenomenon that the recording layer is thermally damaged and the recorded mark M disappears. Therefore, it is necessary to assume that the reproduction power is lower than a certain value. In particular, λ = 35
In the case of the wavelength of 0 to 450 nm, the energy density of the spot S formed on the board surface is larger than that in the case of using the conventional red semiconductor laser (for example, 635 to 830 nm), so that the reproducing power is set to be small. However, because of the above-mentioned limitation of the minimum reproduction power, the allowable range of the reproduction power must be narrowed. In order to increase the resistance to the reproduction power, in other words, to set the reproduction power to a large value, it is necessary that the absorption rates and the transmittances of the recording layers 12 and 123 of the information recording carriers 1 to 5 have small values.

As described above, the general characteristics of a recording device and a reproducing device using a gallium nitride-based compound semiconductor laser as a light emitting element and the physical characteristics when a phase change material is used for the recording layers 12 and 123 are described. Considering comprehensively, the recording power is assumed to be around 6 mW, and the reproduction power is 0.35 m
W or more, and the recording layer 12
This means that an information record carrier in which the record marks M of 123 are not erased is required. In order to satisfy such various restrictions, as the material of the recording layers 12 and 123 of the information recording carriers 1 to 5, it is necessary that the absorption and the transmission have a somewhat high value due to the restriction of the recording power. Due to the limitation on the resistance to the reproduction power, it is necessary that the absorptance and the transmissivity have small values to some extent.

That is, it is necessary to keep the absorptivity and the transmittance within a predetermined range. Since the sum of the absorptance, the transmissivity, and the reflectance is 1, it can be said that it is necessary to keep the reflectance within a predetermined range. The present inventors have experimentally examined the reflectance range that satisfies the various restrictions described above,
A reflectance range of 2 to 26% could be found. Hereinafter, the process will be specifically described as Examples 1 to 7 and Comparative Examples 1 and 2.

[0126] As Examples 1-7 phase change recording type information recording medium 5, using a polycarbonate having a thickness of 1.1mm to the support 13, Ag ₉₈ Pd ₁ Cu ₁ to the reflection layer 121, ZnS on the first protective layer 122 -SiO
2 (80:20, mol%), Ge ₈ S
b ₆₉ Te ₂₃ , ZnS—SiO 2 (8
(0:20, mol%) with various film thicknesses shown in FIG.
It was completed by laminating 0 mm. In the land portion L of the information recording carrier 5, address data by frequency modulation of ± π / 2.5 and a phase selected such that a wave is continuous at a frequency switching point is recorded in a meandering shape. .

This information recording carrier 5 has λ 405 nm, N
It is designed assuming A0.85, and the land part L
The pitch P between them was 0.32 μm. The reflection layer 12
The first protective layer 122 and the second protective layer 124 are formed in a 5 mTorr argon gas atmosphere by a direct current sputtering method, and the first protective layer 122 and the second protective layer 124 are formed by an alternating current sputtering method. The vacuum chamber used for sputtering is used sufficiently evacuated to below previously 1 × 10 ^-6 Torr. Further, the completed information recording carrier 5 includes the light transmitting layer 1.
Initialization was performed by irradiating laser light from the first side to change the phase of the recording layer 123 from an amorphous state having a low reflectance to a crystalline state having a high reflectance.

This information record carrier 5 is set to λ 405 nm, NA
The recording apparatus was mounted on a recording apparatus having a 0.85 pickup, and recording was performed on the land portion L using a modulation signal in which the recording signal was 17PP modulated and the shortest mark length (= 2T) was 0.160 μm. The recording condition was a recording peak power of 6.0.
mW, bias power 2.6 mW, multi-pulse and cooling pulse bottom power 0.1 mW, linear velocity 5.
3 m / s. Recording is so-called multi-pulse recording, and employs ternary power modulation in which the width of the leading pulse and the following pulse is 0.4 times the recording period 1T and the cooling pulse is 0.4 times the recording period 1T. ing.

Subsequently, the information recording carrier 5 is mounted on a pickup 50 of λ 405 nm and NA 0.85 shown in FIG.
And the land L was reproduced. Evaluation items are reflectance, modulation amplitude (= (I8
HI8L) / I8H), deterioration limit reproduction power, reproduction error rate of recording mark M, and address error rate. The degradation limit reproduction power was determined by reproducing the data at a reproduction power of 0.3 mW, gradually increasing the power from the value, and measuring the power at which the reproduction degradation was recognized. Among them, the deterioration limit reproduction power, the reproduction error rate, and the address error rate were determined based on reference values, and the pass / fail was determined.

The reference value of the deterioration limit reproduction power is 0.35
Those which can be reproduced at mW or more were evaluated as good (○), and the others were evaluated as poor (×). The reference value of the reproduction error rate is 0.
Those that can be reproduced at 7 × 10 ⁻⁴ or less were ^evaluated as good (）), and the others were evaluated as poor (×). The reference value of the address error rate was defined as good (（) if the reproduction was possible at 5% or less (limit of restoration by error correction), and poor (x) otherwise. FIG. 15 shows the reflectivity, modulation amplitude, deterioration limit reproduction power, the result of the determination, the result of the error rate determination of the reproduced signal, and the result of the address error rate determination. As shown in FIG. 15, with respect to the information recording medium 5 created with the reflectivity of 12 to 26%, the reproduction deterioration judgment, the reproduction error rate judgment, and the address error rate judgment are all good, and it can be said that the performance as a total system is satisfied.

Comparative Example 1 As a comparative example 1, an information recording carrier 5 in which the configuration of each layer was changed so that the reflectance was 11.0% was prepared, and evaluation was performed in the same manner as in the example. FIG. 15 shows the results. In Comparative Example 1,
Reproduction degradation occurs at 0.34 mW, and it can be said that the recording layer 123 has too high sensitivity. Therefore, it can be said that a reflectance of 11% or less is an information recording carrier that is not suitable for a total system.

Comparative Example 2 As Comparative Example 2, an information recording carrier 5 in which the configuration of each layer was changed so that the reflectance became 28.2% was prepared, and evaluation was performed in the same manner as in the example. FIG. 15 shows the results. In Comparative Example 2,
There is no problem of playback deterioration, but the playback error rate is large,
It was bad. The reason is that the modulation amplitude is 0.38
9 and so on. That is, it is considered that the sensitivity of the recording layer 123 is too low and recording with sufficient contrast is not performed. Therefore, it can be said that a reflectance of 28% or more is an information recording carrier that is not suitable for a total system. As described above, from the results of Examples 1 to 7 and Comparative Examples 1 and 2, it is considered that the reflectance range suitable for the establishment of the total system is 12 to 26%.

As described above, the first reproducing apparatus 40 according to the present invention,
The information recording carriers 1 to 5 mounted thereon have been described. The first playback device 40 described here is a playback device for reading information recorded on the recording layers 12 and 123, and can particularly play back content recorded continuously for a long time. For example, it can be used to reproduce a video-recorded HDTV program or movie.

Next, a second reproducing apparatus 41 according to the present invention will be described with reference to FIG. Here, the case where the information recording carrier 1 is used as the information recording carrier will be described, but the same applies to other cases. Second playback device 41
In the first reproducing apparatus 40 shown in FIG. 13, an auxiliary information demodulator 56 read by the pickup is provided between the pickup 50 and the controller 60, and the rest is the same. For example, it is a playback device for cueing playback of a video-recorded HDTV program or movie and cueing playback of computer data on which data is recorded.

As described above, the signal sent from the pickup 50 to the demodulator 54 is the sum signal (so-called Ia +
Ib + Ic + Id). Where Ia, Ib, I
c and Id respectively correspond to the outputs of the photodetectors divided into four in the DVD defined in JIS standard X6241: 1997. On the other hand, the signal sent from the pickup 50 to the information demodulator 56 is a difference signal (so-called (Ia + Ib)-(Ic + Id)) in the radial direction of the quadrant photodetector. The auxiliary information recorded in the information recording carrier 1 as a groove meandering can be extracted by monitoring the difference signal since the meandering is performed in the radial direction.

The specific configuration of the auxiliary information demodulator 56 comprises at least one of an amplitude modulation demodulator, a frequency modulation demodulator, and a phase modulation demodulator. Specifically, an envelope detection circuit is used for an amplitude modulation demodulator, a frequency detection circuit and a synchronous detection circuit are used for a frequency modulation demodulator, and a synchronous detection circuit and a delay detection circuit are used for a phase modulation demodulator. circuit,
An envelope detection circuit or the like can be preferably used. Incidentally, the difference signal in the radial direction may leak in while the sum signal is small. In order to avoid this, a band pass filter adapted to the frequency band of the auxiliary signal may be connected before the auxiliary information demodulator 56.

Next, the operation of the second reproducing device 41 will be described. The reproduction light 70 is emitted from the light emitting element 50 a of the pickup 50, and the fine pattern 20 of the information recording carrier 1 is
To collect light. Specifically, the fine pattern 20 having a depth of 0.07 to 0.12 mm corresponding to the thickness of the light transmitting layer 11
Focus on Then, groove part G, land part L
Tracking is performed on any one of the. Although this tracking is performed by selecting a predetermined side, it is best to select the land portion L as described above. Subsequently, a radial difference signal ((Ia + I
b)-(Ic + Id)) to the auxiliary information demodulator 56,
Read auxiliary information. At this time, attention is paid to the address information among the various types of auxiliary information, and the data input to the controller 60 is collated with the address for locating the data.

If no match is found, the controller 60 sends a signal to the servo 52 to instruct a search. In the search, the number of revolutions of the motor 51 is reset to a number corresponding to the radius in accordance with the radial movement while scanning the pickup 50 in the radial direction. In the scanning process, the address output from the auxiliary information demodulator 56 receiving the difference signal from the pickup 50 is compared with a predetermined address, and the search is continued until the addresses match. If a match is found, scanning in the radial direction is stopped and switching to continuous playback is made. Sum signal (Ia + I
The output from the demodulator 54 to which (b + Ic + Id) is input becomes a demodulated data stream obtained by cueing, and is input to the interface (I / F) 55. Then, under the control of the controller 60, the signal is sent out.

As described above, according to the second reproducing apparatus 41 of the present invention, the information recording carrier 1 is mounted, and these are the light emitting element 50a having a single wavelength between λ = 350-450 nm. Is designed in conformity with the reproduction light 70 generated by the objective lens 50b having a numerical aperture NA of 0.75 to 0.9. Also play
The cue reproduction of the data stream can be performed.

Next, the recording apparatus 90 according to the present invention will be described with reference to FIG. Here, the case where the information recording carrier 1 is used as the information recording carrier will be described.
The same applies to other cases. The recording device 90 is different from the second reproducing device 41 shown in FIG. Are connected in series, and the rest is the same. The recording device 90 is, for example, a recording device for newly recording computer data at a predetermined address, or for video recording recording of an HDTV program or movie continuously from a predetermined address.

The modulator 82 is a modulator for converting 8 bits of original data into 16 bits in the case of, for example, 8/16 modulation (EFM plus) of DVD. Further, the waveform converter 83 deforms the modulated signal received from the modulator 82 so as to be suitable for recording on the information recording medium 1. Specifically, it is a converter for converting into a recording pulse adapted to the recording characteristics of the recording layer 12 of the information recording carrier 1. For example, when the recording layer 12 is a phase change material, a so-called multi-pulse is formed. That is, the modulation signal is divided into channel bits or smaller units, and the power is changed in a rectangular wave shape. Here, the peak power, the bottom power, the erase power, the pulse time, etc., constituting the multi-pulse are set according to the instruction of the controller 60.

Next, the operation of the recording apparatus 90 will be described. The reproduction light 70 from the light emitting element 50a of the pickup 50
And converge it on the fine pattern 20 of the information recording carrier 1. Specifically, 0.0 which corresponds to the thickness of the light transmitting layer 11 is used.
Focusing is performed on the fine pattern 20 at a depth of 7 to 0.12 mm. Subsequently, tracking is performed on either the groove portion G or the land portion L. Although this tracking is performed by selecting a predetermined side, it is best to select the land portion L as described above. Subsequently, the difference signal in the radial direction from the pickup 50 ((Ia + Ib) −
(Ic + Id)) to the auxiliary information demodulator 56 to read the auxiliary information.

At this time, attention is paid to the address information among the various auxiliary information, and the data inputted to the controller 60 is collated with the address for locating the data. If no match is found, the controller 60 sends a signal to the servo 52 to instruct a search. In the search, the number of revolutions of the motor 51 is reset to a value corresponding to the radius in accordance with the radius movement while scanning the pickup 50 in the radial direction.

In the scanning process, the address output from the auxiliary information demodulator 56 receiving the difference signal from the pickup 50 is collated with a predetermined address, and the search is continued until they match. When a match is found,
The scanning in the radial direction is stopped, and the operation is switched to the recording operation. That is, data input from the interface (I / F) 81 is modulated by the modulator 82 under the control of the controller 60. Then, the controller 6
0 is modulated by the waveform converter 83
Is converted into a format suitable for recording and output to the pickup 50.

In the pickup 50, the recording power is changed to the recording power set by the waveform converter 83, a recording light 80 is generated, and the recording light 80 is irradiated on the information recording carrier 1. Thus, recording is performed at a predetermined address of the information recording carrier 1. Note that even during recording, a difference signal ((Ia
+ Ib)-(Ic + Id)) can be read, and the address can be extracted from the auxiliary information demodulator 56. Therefore, limited area recording up to the address desired by the user is also possible.

As described above, the recording apparatus 9 of the present invention
According to No. 0, the information recording carriers 1 are mounted, which are generated by a light emitting element 50a having a single wavelength between λ = 350-450 nm and an objective lens 50b having a numerical aperture NA of 0.75-0.9. Since it is designed in conformity with the reproducing light 70 and the recording light 80 to be reproduced, it is possible to satisfactorily record the information on the information recording carrier 1 and at the same time, reproduce the auxiliary information and set it at an arbitrary position for recording. Can be delivered.

As described above, the information recording carriers 1 to 5 according to the present invention
The reproduction devices 40 and 41 and the recording device 90 have been described in detail. In the embodiment of the present invention, only the basic part has been described in the embodiment of the present invention, but various modifications and additions other than those described above can be made without impairing the present invention. For example, in addition to the information recording carrier 1 in which the fine pattern 20 has a single layer and two layers, the lamination of the set of the recording layer 7 and the light transmitting layer 8 is repeated a plurality of times to form a multilayer (for example, three layers, four layers) or the like. It may be an extended information record carrier.

The present invention relates to the reproducing devices 40 and 41 and the recording device 90, in addition to the scope described in the claims.
Each operation of the playback devices 40 and 41 and the recording device 90 is also included. It includes a reproducing method and a recording method generated by replacing various operations of the apparatus with steps. It also includes a computer program for executing each step of the reproducing method and a computer program for executing each step of the recording method.

[0149]

As described above, according to the present invention, a support having a fine pattern consisting of a series of substantially parallel grooves in which grooves and lands are alternately formed, and a support formed on the fine pattern. Recording layer, formed on the recording layer,
A light-transmitting layer having a thickness of 0.07 to 0.12 mm, wherein the pitch of the groove or the land is P, the wavelength of the reproduction light is λ, and the numerical aperture of the objective lens is NA. The fine pattern is formed to have a relationship of P <λ / NA, the λ is 350 to 450 nm, and the NA is
Is 0.75 to 0.9, and at least one of the reflectance difference or the phase difference performed so that only one of the land portion and the groove portion has a reflectance of 5% or more. Since the recording based on the information is performed, the cross erase can be reduced and the density can be increased. Further, a practical error rate can be obtained. By setting the reflectance particularly in the range of 12 to 26%, a total system can be established together with the reproducing apparatus and the recording apparatus. Further, since auxiliary information such as address data is recorded in a part or all of the fine pattern by amplitude modulation, demodulation can be performed even in a low C / N environment. In addition, for some or all of the fine patterns,
Since the auxiliary information such as address data is recorded in shape by frequency modulation, it can be demodulated with a simple circuit configuration. In particular, by performing frequency modulation in which the phase is selected so that the waves are continuous at the frequency switching point, the reproduction envelope becomes constant, and stable reproduction is possible. Further, since auxiliary information such as address data is recorded in part or all of the fine pattern by phase modulation, demodulation by synchronous detection enables reproduction even in a low C / N environment. In particular, when the phase difference between the high frequency portion and the low frequency portion constituting the frequency modulation is ± π / 2.5, good signal demodulation can be performed by synchronous detection. The auxiliary information such as the address data is baseband modulated so that the continuation of the same bit is limited to a certain value or less in advance, so that the reading stability can be improved.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an information recording carrier according to a first embodiment of the present invention.

FIG. 2 is an enlarged plan view of the information recording carrier according to the first embodiment of the present invention as viewed from above.

FIG. 3 is a sectional view showing an information recording carrier according to a second embodiment of the present invention.

FIG. 4 is a sectional view showing an information recording carrier according to a third embodiment of the present invention.

FIG. 5 is a sectional view showing an information recording carrier according to a fourth embodiment of the present invention.

FIG. 6 is a sectional view showing an information recording carrier according to a fifth embodiment of the present invention.

FIG. 7 is an enlarged plan view showing an amplitude modulation address recorded on an information recording carrier in the present invention.

FIG. 8 is an enlarged plan view showing a frequency modulation address recorded on an information recording carrier in the present invention.

FIG. 9 shows the first information recorded on the information recording medium according to the present invention.
FIG. 4 is an enlarged plan view showing a phase modulation address of FIG.

FIG. 10 is an enlarged plan view showing a second phase modulation address recorded on the information recording carrier in the present invention.

FIG. 11 is a diagram illustrating changes in basic data before and after baseband modulation.

FIG. 12 is a diagram illustrating a specific example of a change in a data sequence before baseband modulation and after baseband modulation.

FIG. 13 is a block diagram showing a first reproducing apparatus according to the present invention.

FIG. 14 is a diagram showing a relationship between a reflectance and an error rate.

FIG. 15 is a diagram showing reflectance and reproduction characteristics of Examples 1 to 7 and Comparative Examples 1 and 2.

FIG. 16 is a block diagram showing a second playback device according to the present invention.

FIG. 17 is a block diagram showing a recording apparatus according to the present invention.

FIG. 18 is a sectional view showing a conventional information recording carrier.

FIG. 19 is an enlarged plan view of a conventional information recording medium as viewed from above.

[Explanation of symbols]

1, 2, 3, 4, 5 ... information recording carrier, 11, 11a ... light transmitting layer, 11b ... adhesive light transmitting layer, 12 ... recording layer, 13 ... support, 14 ... resin layer, 20, 21, 22 ... fine pattern, 40, 41 ... reproduction device, 50 ... pickup, 50
a: light emitting element, 50b: objective lens, 51: motor, 5
2 servo, 53 turntable, 54 demodulator, 5
5, 81 interface (I / F), 56 auxiliary information demodulator, 60 controller, 70 reproduced light, 80
Recording light, 82: modulator, 83: waveform converter, 90: recording device, 121: reflective layer, 122: first protective layer, 123 ...
Recording layer, 124: second protective layer, 250: address by amplitude modulation, 300: address by frequency modulation, 400
... First phase modulation address, 450 ... Second phase modulation address, G ... Groove part, L ... Land part

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G11B 7/004 G11B 7/004 Z 7/007 7/007 11/105 521 11/105 521F 531 531E 531F 20 / 12 20/12 F term (reference) 5D029 JA01 JC02 LB04 LB07 LB11 LC08 WA02 WB11 WC05 WC06 WD10 WD16 5D044 BC04 CC01 CC04 CC08 DE37 5D075 EE03 FG04 FG18 5D090 AA01 AA03 AA04 BB03 CC01 BB04 GG03 CC01

Claims (15)

[Claims] 1. A support having a fine pattern consisting of a series of substantially parallel grooves in which groove portions and land portions are alternately formed, a recording layer formed on the fine pattern, and a recording layer formed on the recording layer. Formed, thickness 0.07 ~ 0.12m
m, wherein the pitch of the groove or land is P, the wavelength of the reproduction light is λ, and the numerical aperture of the objective lens is NA, and the fine pattern is P <λ / NA. Formed with the relationship of
The λ is 350 to 450 nm, and the NA is 0.75 to
0.9, and recording based on at least one of the reflectance difference or the phase difference is performed so that the reflectance is 5% or more in only one of the land portion and the groove portion. An information record carrier characterized by the fact that: 2. The information recording carrier according to claim 1, wherein said recording layer is made of a phase change material. 3. The phase change material is Ge—Sb—Te, A
g-In-Te-Sb, Cu-Al-Sb-Te, Ag
3. The information recording carrier according to claim 2, wherein the information recording carrier is an alloy material containing at least one of -Al-Sb-Te. 4. The information recording carrier according to claim 1, wherein a hard coat layer is provided on a side of said light transmitting layer opposite to said recording layer. 5. The information recording carrier according to claim 1, wherein auxiliary information is recorded in a part or all of said fine pattern by amplitude modulation. 6. The information recording carrier according to claim 1, wherein auxiliary information is recorded in a part or all of the fine pattern by frequency modulation. 7. The information recording carrier according to claim 6, wherein the frequency modulation is a frequency modulation in which a phase is selected so that a wave is continuous at a frequency switching point. 8. The information recording carrier according to claim 1, wherein auxiliary information is recorded in a part or all of said fine pattern by phase modulation. 9. The information recording carrier according to claim 6, wherein a phase difference between a high frequency portion and a low frequency portion constituting the frequency modulation is ± π / 2.5. 10. The information recording carrier according to claim 6, wherein a phase difference between a high frequency portion and a low frequency portion constituting the frequency modulation is ± π / 4. 11. The information according to claim 5, wherein the auxiliary information is data that has been subjected to baseband modulation so that the continuation of the same bit is limited to a certain value or less in advance. Record carrier. 12. The information recording carrier according to claim 11, wherein said baseband modulation is a Manchester code. 13. The apparatus according to claim 5, wherein the auxiliary information is recorded in a part of the fine pattern.
13. The information recording carrier according to any one of the above items 12 to 12. 14. The wavelength of the reproduction light is λ and RIN-125d
A light-emitting element having a noise of B / Hz or less and a numerical aperture NA
A reproducing apparatus for reproducing an information recording carrier having a fine pattern composed of a series of substantially parallel grooves in which groove portions and land portions are alternately formed, the λ being 350 ４５０450 nm, the NA is 0.75
14. A reproducing apparatus comprising: mounting the information recording carrier according to any one of claims 1 to 13; and irradiating only one of the groove portion and the land portion with the reproduction light. 15. The recording light having a wavelength of λ and RIN-125d
A light-emitting element having a noise of B / Hz or less and a numerical aperture NA
A recording device having at least an objective lens, and recording on an information recording carrier having a fine pattern comprising a substantially parallel groove continuum in which groove portions and land portions are alternately formed, wherein the λ is 350 to 450 nm, the NA is 0.75
14. A recording apparatus comprising: mounting the information recording carrier according to any one of claims 1 to 13; and irradiating only one of the groove portion and the land portion with the recording light.