JP2002117589A - Optical recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new format method of a rewritable DVD system, which uses a semiconductor laser having an oscillation wavelength in a short wavelength compared with the conventional system and is effective to eliminate an unrecorded area in a data adding part being the same as that of an LPP method and also to provide an excellent method in which a data error does not occur, due to minute cut width control in producing a stamper and the leakage of an LPP signal to a data part compared with a DVD-R land prepit method. SOLUTION: In this optical recording medium is provided with a recording layer on a substrate and is provided with a reflection layer in the case of necessity, the substrate has 4 to 96 T wobble frequency (cycle length). The optical recording medium has an organic dye film in which the refractive index (n) of a recording layer single layer is 1.5<=n<=3.0 with respect to the light of a wavelength region of ±5 nm recording and reproduction wavelength as a recording layer and an extinction coefficient (k) is 0.02<=k<=0.2. When substrate groove depth is defined as d1 (Å) and a wobble frequency is defined as m (T), 4,000<=d1×m<= 2,400.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information recording medium, and more particularly, to irradiating a light beam to cause an optical change in the transmittance and reflectance of a recording material, thereby recording information. The present invention relates to an information recording medium on which information can be reproduced and additionally recorded. Specifically, it is used for a write-once optical disc for data, a write-once compact disc, and the like, and is applied to CD-I, CD-V, DVD-R, and the like.

[0002]

2. Description of the Related Art As a conventional technique of a data write-once disc, a technique using a cyanine dye as a recording material is disclosed in JP-A-57-82093, JP-A-58-56892, and JP-A-58-112790. No., JP-A-58-
No. 114989, JP-A-59-85791,
JP-A-60-83236, JP-A-60-8984
No. 2, JP-A-61-25886, and the like, using a phthalocyanine dye as a recording material are disclosed in JP-A-61-150243 and JP-A-61-25843.
177287, JP-A-61-154888, JP-A-61-246091, JP-A-62-3
No. 9286, JP-A-63-37791, JP-A-63-39888, and the like.

Further, as a conventional technology of a write-once compact disc, those using a cyanine dye / metal reflective layer as a recording material are disclosed in JP-A-1-159842, JP-A-2-42652, and JP-A-2-13656. No.
JP-A-2-176446 and JP-A-2-176585 disclose phthalocyanine (azaannulene) dyes as recording materials.
JP-A-215466, JP-A-4-113886, JP-A-4-226390, JP-A-5-127
No. 2, JP-A-5-171052, JP-A-5-17052
116456, JP-A-7-268227,
Japanese Patent Application Laid-Open Nos. Hei 7-31497 and 1979, which use an azo metal chelate dye as a recording material, are disclosed in JP-A-4-46186, JP-A-4-141489, and JP-A-4-36088. JP-A-5-27
9580, JP-A-7-51673, JP-A-7-16069, JP-A-7-372272, JP-A-7-71867, JP-A-8-2318
No. 66, JP-A-8-295811 and the like.

[0004] As a conventional technique of a large capacity write-once compact disc (DVD-R), a technique using a cyanine dye + metal reflective layer as a recording material is known as PIONEER R & D vo vo.
l.6 No.2: Development of DVD-Recordable, Basic Development of DVD-R Dye Disc ISOM / ODS'96: High Densit
y of recording on Dye material Disc approach for
4.7 GB, and those using a polymethine dye as a recording material are disclosed in JP-A-10-83577 and JP-A-1
0-119434, JP-A-10-149584, JP-A-10-188339,
Japanese Patent Application Laid-Open Nos. 10-109475 and 10-109476 disclose a recording material using a polymethine dye and a light stabilizer as a recording material.
JP, JP-A-10-134413, JP-A-10-134413
Japanese Patent Application Laid-Open No. 5-67438 and Japanese Patent Application Laid-Open No. 7-1610 disclose an azo metal chelate dye / metal reflective layer as a recording material.
No. 69, JP-A-8-156408, JP-A-8-156408
JP-A-231866, JP-A-8-332772, JP-A-9-58123, JP-A-9-1750
No. 31, JP-A-9-193545, JP-A-9-193545
-274732, JP-A-9-277703, JP-A-10-6644, JP-A-10-665
0, JP-A-10-6651, JP-A-10-65
JP-A-369693, JP-A-10-44606, JP-A-10-58828, and JP-A-10-86519.
JP, JP-A-10-149584, JP-A-10-149584
-157293, JP-A-10-157300, JP-A-10-157301, JP-A-10-1
No. 57302, JP-A-10-181199,
JP-A-10-181201, JP-A-10-181
No. 203, JP-A-10-181206, JP-A-10-188340, JP-A-10-18834
No. 1, JP-A-10-188358, JP-A-10-188358
JP-A-208303, JP-A-10-214423, JP-A-10-228671, JP-A-10-208
Japanese Patent Application Laid-Open Nos. 9-267562 and 9-29, which disclose tetraazaporphyrin (porphyrazine) dye / metal reflective layer as a recording material, are disclosed in JP-A-36693 and JP-A-11-12483. -309
No. 268, Japanese Patent Application Laid-Open No. 10-856, etc., which use a cyanine dye + azo metal chelate dye / metal reflective layer as a recording material are disclosed in Japanese Patent Publication No. 7-516.
No. 82, Japanese Unexamined Patent Publication No. 11-34499, etc., which use a formazan (metal chelate) dye / other dye as a recording material are disclosed in Japanese Patent No. 27919.
No. 44, JP-A-8-295079, JP-A-9-095520, JP-A-9-193546, JP-A-10-337958, etc., and dipyrromethene (metal chelate) dye + Japanese Patent Application Laid-Open No. H10-1624 uses other dyes as recording materials.
No. 30, JP-A-10-166732, JP-A-10-226172, JP-A-11-42858, JP-A-11-42858, JP-A-11-0
No. 92682, JP-A-11-165465,
JP-A-11-208111, JP-A-11-227
332, JP-A-11-227333, JP-A-11-255774, JP-A-11-25605
Japanese Patent Application Laid-Open No. 10-865 discloses a recording material using another dye / metal reflective layer as a recording material.
No. 17, JP-A-10-93788, JP-A-10-93788
JP-A-226172, JP-A-10-244758, JP-A-10-287819, JP-A-10-
297103, JP-A-10-309871, JP-A-10-309872 and the like.

At present, as a next-generation large-capacity optical disk, DV
Development of DR is in progress. Development of recording materials for miniaturization of recording pits,
It is necessary to develop technology such as adoption of image compression technology represented by PEG2 and shortening of the wavelength of a semiconductor laser for reading recorded pits.

Heretofore, as a semiconductor laser in the red wavelength region, a 670 nm band Al for a bar code reader and a measuring instrument has been used.
Although only GaInP laser diodes have been commercialized, red lasers are being used in the optical storage market in earnest as the density of optical disks increases. DVD
In the case of a drive, 635 nm band and 650 nm
It is standardized at two wavelengths of the laser diode in the band. On the other hand, the DVD-ROM drive for reproduction only has a wavelength of ~
Commercialized at 650 nm. Under these circumstances, the most preferable DVD-R media has a wavelength of 630 to 680.
It is a medium that can record and reproduce in nm.

[0007] The format of DVD-R media is standardized as a format called a land pre-pit in which a part of a land portion is cut. With this method, if the land pre-pit signal (LPPb) is 0.16 or less, pre-pit information such as a pre-pit address cannot be reproduced satisfactorily. If the land pre-pit signal (LPPb) is 0.32 or more, the LPP signal itself becomes noise-like in the data area. Behavior and many data errors occur. Therefore, the LPP adjusts the cut width suitable for the recording material to 0.16 by fine adjustment using a stamper or the like.
The land cut width must be controlled so that ≤ LPPb ≤ 0.32.

Japanese Patent Application Laid-Open No. Hei 10-124878 discloses that in a land / groove recording type optical disk having a preformat ID for each sector, when a groove is wobbled for disk rotation control or clock signal generation, a land track is generated. In order to prevent interference of wobble signals from the grooves on both sides with respect to, the track ID is not included in the sector ID information for modulating the wobble, only the zone number and the sector number, and the wobbles of the adjacent grooves are aligned in phase. And JP-A-11-2730.
No. 90 discloses a track having a constant groove width and land width for recording and reproducing data at high density and high accuracy, and wobbles in a radial direction at a constant frequency when rotated at CAV. A multiplex mark is superimposed on one or both of the left and right side walls of the track of the optical disc in correspondence with the data bit of the address information, and the adjacent tracks (land and groove) are respectively adjusted so that the phase of the multiplex mark matches. Japanese Patent Application Laid-Open No. H11-328681 describes that a clock track is arranged near the outer edge of a radially partitioned disk, and a clock pattern corresponding to each data zone on a one-to-one basis. Record and use it as reference clock information to generate the write clock signal required for writing to each data zone. This eliminates the need for a physical sector configuration in which the synchronization field and the edit block are provided adjacent to the write area, increases the storage capacity, and provides a redundant additional track on the clock track in parallel with the original clock track. This simplifies the fine positioning control of the conventional reference clock converter.

[0009]

SUMMARY OF THE INVENTION The present invention is a new format system of a write-once DVD system using a semiconductor laser having an oscillation wavelength shorter than that of the above-mentioned conventional system. The present invention provides an effective method for eliminating an unrecorded area in a copy unit. Also, compared to the DVD-R land pre-pit method, fine cut width control and LP
An object of the present invention is to provide an excellent method that does not cause a data error due to leakage of a P signal to a data portion.

[0010]

As a result of extensive studies by the present inventors, the substrate has a wobble having a frequency of 4T to 96T, and the recording layer has a single layer of recording layer for light having a recording / reproducing wavelength of ± 5 nm. Has an organic dye film having a refractive index n of 1.5 ≦ n ≦ 3.0 and an extinction coefficient k of 0.02 ≦ k ≦ 0.2, and is combined with an optimum groove shape to perform optical recording. It has been found that by creating a medium, the unrecorded area at the head of the rewritten data portion can be reduced, and a DVD write-once disc with a low error rate can be obtained. That is, the present invention was achieved by combining a high frequency wobble format, an optimum groove shape, and an organic dye.

[0011] The object of the present invention is to provide (1) an optical recording medium comprising a recording layer provided on a substrate and a reflective layer provided as necessary, wherein the substrate has a wobble having a frequency (period length) of 4T to 96T. The refractive index n of the recording layer single layer with respect to light in the wavelength range of recording / reproducing wavelength ± 5 nm as the recording layer is 1.5 ≦ n ≦
An optical recording medium having an organic dye film having an extinction coefficient k of 0.02 ≦ k ≦ 0.2, wherein the substrate groove depth d1 (Å), wobble frequency m (T), When you do, 40
00 ≦ d1 × m ≦ 240000, ”(2)“ where the step between the land and the groove when the dye film is formed is d2 (Å), 12
00 ≦ d2 × m ≦ 160000, the optical recording medium according to the above item (1) ”, (3)“ when the half width of the groove of the substrate is W1 (μm), 0.7 ≤W1
× m ≦ 40, the optical recording medium according to the above (1) or (2), ”(4)“ when the wobble amount of the wobble of the substrate is W2 (Å). , 2 ≦ W2 /
m.ltoreq.500, wherein the optical recording medium according to any one of the above items (1) to (3) ", (5)
"When the track pitch of the substrate is Tr (μm), 2 ≦ Tr × m ≦ 80, and the optical recording medium according to any one of the above items (1) to (4). ”, (6)“ Wobble amplitude Wo and push-pull amplitude P
P (Wo / PP) is 0.1 ≦ Wo / PP ≦ 0.
4. The optical recording medium according to any one of the above items (1) to (5), wherein the organic dye of the recording layer is a metal chelate dye or polymethine. (8) The optical recording medium according to any one of (1) to (6), wherein the optical recording medium contains at least one of a dye, a squarylium dye, and an azaannulene dye. "The metal chelate dye of the recording layer,
Azo metal chelate dye, formazan metal chelate dye,
The optical recording medium according to any one of the above items (1) to (7), which is any one of a dipyrromethene metal chelate dye, and (9) "a metal of the metal chelate dye of the recording layer." But nickel, copper, cobalt, manganese,
(10) The optical recording medium according to (7) or (8), wherein the polymethine dye in the recording layer is a trimethine cyanine dye, and an azaannulene-based dye. Is a tetraazaporphyrin dye, the optical recording medium according to the above item (7) ", (11)" the recording layer has a decomposition onset temperature of 36.
The optical recording medium according to any one of the above items (1) to (10), wherein the temperature is 0 ° C. or lower ”, (12)
"If the reflective layer is required, the reflective layer is made of gold, silver, aluminum, or an alloy of another metal containing these as a main component, wherein the reflective layer is made of gold, silver, aluminum, or an alloy thereof. (13) The optical recording medium according to any one of the above,
The optical recording medium according to any one of the above items (1) to (12),
(14) "recording and / or reproducing the optical recording medium according to any one of the above items (1) to (12) using an optical pickup having a recording wavelength of 600 to 720 nm. Optical recording method ".

The effects of the respective items are described below. Item (1) is the basic structure and material structure of the optical recording medium of the present invention and the optimum substrate groove depth range. Item is the limitation of the optimum groove step range when the dye recording layer is provided in the item (1), and the item (3) is the optimum groove shape in the items (1) and (2). It is limited to the optimal range of width,
The item (4) is the optimum range of the wobble shake amount in the items (1) to (3), and the item (5) is the item (1) to the item (4). The item (6) is the optimum limit of the track pitch, and the item (6) is the item of the optimum range of the normalized wobble amplitude signal. The item (7) is a limitation on the composition of organic materials usable for the recording layer, the item (8) is a limitation on the material of the chelating dye, and the item (9) is a chelating metal used. (Material optimization). The item (10) is a limitation on the structure of the non-chelating dye used in the recording layer, the item (11) is a limitation on the thermophysical properties of the recording material, and the item (12) is that the reflection layer is This is the limitation of the optimum material when used, and the above-mentioned item (13) is the limitation of the recording wavelength in the present invention. The first (1)
Item 4) is an optical recording method using the optical recording medium of items 1) to 12).

[0013] The optical recording medium of the present invention has a substrate of 4T to 96T.
T has a high frequency wobble, and has a refractive index n of a single recording layer for light in a wavelength range of recording / reproducing wavelength ± 5 nm as a recording layer.
Is 1.5 ≦ n ≦ 3.0, and the extinction coefficient k is 0.02 ≦
It has an organic dye film in which k ≦ 0.2. Note that T defined here is the recording pit length (unit: μm) when recording at the basic clock frequency.
In the case of DVD (4.7 GB) media, it is about 0.133 μm.

Usually, the wobble frequency band is 150T-4.
00T equivalent is used. In this frequency band,
Regardless of the frequency modulation or the phase modulation, when data is added, the frequency of the wobble is too low, so that there is a considerable gap between the previous data and the added data, which is not suitable for high-density recording. On the other hand, in the DVD-R, an LPP is provided, and the position where data is written is controlled by the LPP signal. However, in the LPP method, if the amplitude of the LPP is too small, the LPP signal cannot be read well,
If P is too large, the LPP signal leaks into the write data and a data error occurs frequently. Therefore, LPP is in the range of 0.16 ≦ LPPb ≦ 0.32, preferably 0.18 ≦ LPPb ≦ 0. .26, and the cut width of the land must be finely controlled when the stamper is formed.

On the other hand, if a high-frequency wobble is used, the LPP is not necessary, and the wobble can be modulated and synchronized, so that a situation in which data errors frequently occur unlike the LPP method does not occur.

In the present invention, the wobble amplitude is
The ratio Wo / PP = NWO of the wobble amplitude (Wo) after the appropriate filtering to the wobble amplitude (Wo) after the appropriate filtering is also 0.1 ≦ NWO.
If the value is in the range of ≦ 0.4, synchronization with the wobble, which is the object of the present invention, is possible, and the more preferable NWO value is in the range of 0.15 ≦ NWO ≦ 0.30. NWO
Is less than 0.1, the signal strength is insufficient to achieve synchronization, and if it exceeds 0.4, data part errors tend to increase. However, compared to the LPP method, L
The influence of the occurrence of a data error is smaller than the data error of a medium having a large PP, and the data error associated with an increase in wobble amplitude is moderate. When creating a stamper, the LPP cut width of the LPP method is 0.16 ≦ LP.
In order to make the range of Pb ≦ 0.32, an advanced cut width control technique is required. However, in the high frequency wobble system of the present invention, the magnitude of the high frequency generation source and the wobble swing amount (the wobble swing amount is controlled). The objective can be achieved if only the swing amount can be arbitrarily created with high reproducibility in the circuit), so that the yield of the stamper and the yield of the media can be dramatically improved.

The groove shape of the substrate having the above-mentioned format is such that a recording layer is formed mainly by a solvent coating method using an organic dye. In this case, the optimum groove depth is 300 to 2 mm.
500 °, more preferably 1500 ° to 200 °
0 °. In particular, in the solvent coating method (however, a signal can be obtained even at 300 ° in the case of dye vapor deposition), if the groove depth is 1000 ° or less, a push-pull signal cannot be sufficiently obtained, and tracking control cannot be performed. On the other hand, if the angle is 2500 ° or more, the transferability during the molding of the substrate is undesirably increased. When a dye is provided by using a substrate in this range, the step between the land and the groove becomes 600 to 1600 °, and the step difference between the land and the groove is 300 °.
Å is the optimal step. In addition, recording density of 4 GB to 5 G
In order to secure the capacity of B, the track pitch is 0.6
About 4 μm to 0.8 μm is required. Although the groove width varies depending on the recording material, it can be applied to almost all organic materials with a half width of 0.15 to 0.44 μm, more preferably 0.18 to 0.40 μm.

In this structure, the wobble frequency is m (T), the groove depth of the substrate is d1 (Å), the groove depth of the land and groove when the dye layer is provided is d2 (Å), The track pitch is Tr (μm) and the half width of the groove of the substrate is W1 (μm).
m), and assuming that the wobble swing width is W2 (Å), the relational expression between the optimum frequency and the groove shape in the high-frequency wobble format described above holds as follows.

[0019]

## EQU1 ## 4000 ≦ d1 × m ≦ 240000 1200 ≦ d2 × m ≦ 160000 0.7 ≦ W1 × m ≦ 40 2 ≦ W2 / m ≦ 500 2 ≦ Tr × M ≦ 80

Accordingly, the present invention quantifies the relational expression between the optimal format and the optimal groove shape range when using a high-frequency wobble and further using an organic dye in the recording layer.

Next, the configuration of the recording medium will be described.
Items necessary for forming the recording layer include optical characteristics. The conditions required for the optical characteristics are that the recording / reproducing wavelength has a large absorption band on the short wavelength side with respect to the recording / reproducing wavelength of 630 nm to 690 nm, and the recording / reproducing wavelength is near the long wavelength end of the absorption band. is there. This means that it has a large refractive index and an extinction coefficient in the recording / reproducing wavelength of 630 to 690 nm.

More specifically, the refractive index n of the single recording layer with respect to light in the wavelength region near the long wavelength near the recording / reproducing wavelength is 1.5 or more and 3.0 or less, and the extinction coefficient k is 0.02 or more. 0.2
It is preferably within the following range. When n is less than 1.5, it is difficult to obtain a sufficient optical change, so that the recording modulation degree becomes low, which is not preferable. When n exceeds 3.0, the wavelength dependency becomes too high. Therefore, an error occurs even in the recording / reproducing wavelength region, which is not preferable. When k is less than 0.02, the recording sensitivity deteriorates, which is not preferable. When k exceeds 0.2, it is difficult to obtain a reflectance of 50% or more, which is not preferable.

The conditions required for the substrate shape are that the track pitch on the substrate is 0.7 to 0.8 μm and the groove width is 0.18 to 0.40 μm in half width.

Next, specific examples of the dye material usable in the present invention include an azo (metal chelate) dye, a formazan (metal chelate) dye, and dipyrromethene (metal chelate).
Dyes, polymethine dyes, squarylium dyes, azaannulene dyes and the like can be applied, and specifically, metal chelate dyes, trimethine cyanine dyes, squarylium dyes, and tetraazaporphyrin dyes are particularly preferable.

Here, the azo (metal chelate) dye has an azo bond and the azo compound forming units on both sides are substituted or unsubstituted aromatic ring, pyridine residue, pyrimidine residue, pyrazine residue, pyridazine residue. , A triazine residue,
An azo compound is formed by a combination of an imidazole residue, a thiazole residue, a triazole residue, a pyrazole residue, an isothiazole residue, a benzothiazole residue, and a metal chelate compound of these azo compounds is particularly preferable.

The formazan (metal chelate) dye is represented by the following formula (1).

[0027]

Embedded image (In the formula, Z is a residue that forms a polyheterocyclic ring together with the carbon atom and the nitrogen atom to which it is bonded, and specifically includes a pyridazine ring, a pyrimidine ring, a pyrazine ring, and a triazine ring. The heterocyclic ring may have a substituent such as an alkyl group, an alkoxy group, an alkylthio group, a substituted amino group, an allyl group, an allyloxy group, an anilino group, a keto group, etc. A is an alkyl group, Aralkyl groups,
Represents an allyl group or a cyclohexyl group, and may have a substituent such as an alkyl group, an alkoxy group, a halogen group, a keto group, a carboxyl group or an ester thereof, a nitrile group, or a nitro group. B represents an allyl group, which may have an alkyl group, an alkoxy group, a halogen group, a carboxyl group, or a substituent thereof such as an ester, a nitrile group, and a nitro group. In the case of a metal chelate, the metal is a divalent metal atom. )

As a dipyrromethene (metal chelate) dye, the general formula of the dipyrromethene compound is shown by the following formula (2).

[0029]

Embedded image (Wherein R _{1 to} R ₉ each independently represent a hydrogen atom, a halogen atom, an unsubstituted alkyl group, an alkoxy group, an alkenyl group, an acyl group, an alkoxycarbonyl group, an aralkyl group, an aryl group, or a heteroaryl group. In the case of a metal chelate, the metal is a divalent metal atom.)

When the azo compound, formazan compound or dipyrromethene compound is a chelate compound, the metal may be a transition metal, for example, Ni, Co, Cu, Mn, VO,
Examples include Zn, Fe, Cr, and Al. Ni, Co, Cu, Mn, and VO are particularly preferable in terms of production and disk characteristics.

As the polymethine dye, 530 nm to 6
Although a dye having an absorption band at 00 nm is applicable to the present invention, a trimethine cyanine dye is particularly preferable, and both ends of the trimethine chain are unsubstituted indolenine, and benzindolenine is particularly preferable. ClO _4, BF _4, in addition to PF _6, SbF _6, etc., may be various metal chelate anion typified by nickel dithiolate complexes.

Examples of the squarylium dye include squarylium formed by a combination of unsubstituted indolenine, benzindolenine, pyrazole, carbazole, quinoxaline, isoindole, aromatic ring, and substituted amino group residue at both ends of the squalene ring. Dyes are preferably used in the present invention.

Examples of the azaannulene-based dyes include phthalocyanine, naphthalocyanine, tetrapyrazinoporphyrazine, tetrapyridinoporphyrazine, tetraazaporphyrin and the like, each having a specific substituent. Of these, tetraazaporphyrin is particularly preferred. Azaporphyrin is preferred, followed by tetrapyridinoporphyrazine, tetrapyrazinoporphyrazine, and phthalocyanine.

Regarding the thermal decomposition characteristics of the dye, the recording material preferably has a decomposition onset temperature of 360 ° C. or lower, particularly 10
0-350 ° C is preferred. If the decomposition temperature is 360 ° C. or higher, pit formation during recording is not performed well, and jitter characteristics are poor. If the temperature is lower than 100 ° C., the storage stability of the disc will deteriorate.

Hereinafter, the optical recording medium of the present invention will be described with reference to the drawings. 1. Structure of Recording Body The recording body of the present invention comprises the structure of FIG. 1 which is a normal write-once optical disc (a so-called air sandwich in which two sheets of FIG. 1 are bonded, or a close bonding structure), and FIG. The structure may be a CD-R medium.

Required Characteristics of Each Layer and Examples of Constituent Materials The structure of the recording medium of the present invention is basically the structure shown in FIG. 3 in which a first substrate and a second substrate (protective substrate) are bonded together via a recording layer with an adhesive. Structure. The recording layer may be a single layer of an organic dye layer, or may be a laminate of an organic dye layer and a metal reflective layer to increase the reflectance. The recording layer and the substrate may be layered with an undercoat layer or a protective layer interposed therebetween, or may be formed by laminating them for improving the function. The most commonly used is the first
This is the structure of substrate / recording layer (organic dye layer) / metal reflective layer / protective layer / adhesive layer / second substrate.

<Substrate> A necessary characteristic of the substrate used in the present invention is that the substrate must be transparent to the laser beam used only when recording and reproduction are performed from the substrate side, and when recording and reproduction are performed from the recording layer side. The substrate need not be transparent.
Therefore, in the present invention, when two layers are used, the first substrate may be transparent or opaque as long as only the second substrate is transparent. As a substrate material, for example, a plastic such as polyester, acrylic resin, polyamide, polycarbonate resin, polyolefin resin, phenol resin, epoxy resin, polyimide, glass, ceramic, or metal can be used. When only one substrate is used, or when two substrates are used in a sandwich form, a guide groove and a guide pit for tracking are formed on the surface of the first substrate, and a preformat such as an address signal is formed. Need to be.

<Recording Layer> The recording layer is capable of causing some optical change upon irradiation with a laser beam and recording information by the change. The recording layer contains the dye of the present invention. In forming the recording layer, the dye of the present invention may be used alone or in combination of two or more. Further, the dye of the present invention may be used by mixing or laminating with other organic dyes, metals and metal compounds for the purpose of improving optical characteristics, recording sensitivity, signal characteristics and the like. Examples of organic dyes include polymethine dyes, naphthalocyanine-based, phthalocyanine-based, squarylium-based,
Croconium-based, pyrylium-based, naphthoquinone-based, anthraquinone-based (indanthrene-based), xanthene-based, triphenylmethane-based, azulene-based, tetrahydrocholine-based, phenanthrene-based, triphenothiazine-based dyes, metal complex compounds, and the like. The above dyes may be used alone or in combination of two or more.

In addition, metals and metal compounds such as In, Te, Bi, Se, Sb, Ge, Sn, A
1, Be, TeO ₂ , SnO, As, Cd and the like can be used in the form of dispersion mixing or lamination. Further, a polymer material in the dye, for example, an ionomer resin, a polyamide resin, a vinyl resin, a natural polymer, silicone,
Various materials such as liquid rubber, or a silane coupling agent may be dispersed and mixed, or a stabilizer (for example, a transition metal complex), a dispersant, a flame retardant,
It can be used together with a lubricant, an antistatic agent, a surfactant, a plasticizer and the like.

The recording layer can be formed by ordinary means such as vapor deposition, sputtering, CVD or solvent coating. When using a coating method, the dye or the like is dissolved in an organic solvent or the like, and the coating is performed by a conventional coating method such as spraying, roller coating, dipping, and spin coating.

As the organic solvent to be used, generally, alcohols such as methanol, ethanol and isopropanol, ketones such as acetone, methyl ethyl ketone and cyclohexanone, N, N-dimethylformamide,
Amides such as N, N-dimethylacetamide, sulfoxides such as dimethyl sulfoxide, ethers such as tetrahydrofuran, dioxane, diethyl ether, ethylene glycol monomethyl ether, esters such as methyl acetate and ethyl acetate, chloroform, methylene chloride, dichloroethane , Carbon tetrachloride, aliphatic halogenated hydrocarbons such as trichloroethane, benzene, xylene,
Aromatics such as monochlorobenzene and dichlorobenzene,
Examples include cellosolves such as methoxyethanol and ethoxyethanol, and hydrocarbons such as hexane, pentane, cyclohexane, and methylcyclohexane. The thickness of the recording layer is 100 to 10 μm, preferably 200 to 2 μm.
2,000 is appropriate.

<Undercoat Layer> The undercoat layer comprises (a) an improvement in adhesiveness, (b) a barrier against water or gas, (c) an improvement in storage stability of the recording layer, and (d) an improvement in reflectance. , (E) protection of the substrate and the recording layer from a solvent, and (f) formation of guide grooves, guide pits, preformats, and the like.

For the purpose of (a), a polymer material such as an ionomer resin, a polyamide resin, a vinyl resin, a natural resin, a natural polymer, various polymer compounds such as silicone and liquid rubber, and a silane cup A ring agent or the like can be used. For the purposes (b) and (c),
In addition to the polymer materials, inorganic compounds such as SiO, M
gF, SiO ₂ , TiO, ZnO, TiN, SiN and the like, and furthermore, a metal or semimetal such as Zn, Cu, N
i, Cr, Ge, Se, Au, Ag, Al and the like can be used. For the purpose of (d), a metal such as Al, Au, Ag, etc., an organic thin film having metallic luster,
For example, a methine dye, a xanthene dye, or the like can be used. For the purposes (e) and (f), an ultraviolet curable resin, a thermosetting resin, a thermoplastic resin, or the like can be used. The thickness of the undercoat layer is suitably 0.01 to 30 μm, preferably 0.05 to 10 μm.

<Metal Reflective Layer> The metal reflective layer is made of, for example, metals and semi-metals which are highly resistant to corrosion and can provide a high reflectance by themselves. Examples of materials include Au, Ag, Cr, Ni, Al and F.
e, Sn and the like.
u, Ag, and Al are most preferred. These metals and metalloids may be used alone or as two kinds of alloys. Examples of the film forming method include vapor deposition and sputtering, and the film thickness is 50 to 5000 °, preferably 100 to 30 °.
00 °.

<Protective Layer, Hard Coat Layer on Substrate Surface> The protective layer and the hard coat layer on the substrate surface (a) protect the recording layer (reflection / absorption layer) from scratches, dust, dirt, etc., and (b) the recording layer ( It is used for the purpose of improving the storage stability of the reflection / absorption layer), (c) improving the reflectance, and the like. For these purposes, the materials shown in the undercoat layer can be used. Further, as the inorganic material, SiO, SiO ₂ or the like can be used, and as the organic material, polymethyl acrylate, polycarbonate, epoxy resin, polystyrene,
Heat-softening and heat-melting resins such as polyester resin, vinyl resin, cellulose, aliphatic hydrocarbon resin, natural rubber, styrene butadiene resin, chloroprene rubber, wax, alkyd resin, drying oil, and rosin can also be used.

The most preferable example of the material for the protective layer or the hard coat layer on the substrate is an ultraviolet curable resin having excellent productivity. The thickness of the protective layer or the hard coat layer on the substrate surface is 0.01 to 30 μm, preferably 0.05 to 1 μm.
0 μm is appropriate. In the present invention, the undercoat layer,
The protective layer and the hard coat layer on the substrate side may contain a stabilizer, a dispersant, a flame retardant, a lubricant, an antistatic agent, a surfactant, a plasticizer, and the like as in the case of the recording layer.

<Protective Substrate> The protective substrate must be transparent to the laser beam to be used when irradiating a laser beam from the protective substrate side. Usable substrate materials are exactly the same as the above-mentioned substrate materials, and include polyester, acrylic resin, polyamide, polycarbonate resin, polyolefin resin, phenol resin, epoxy resin, plastic such as polyimide, or glass, ceramic, or metal. Can be used.

<Adhesive, Adhesive Layer> Any known material that can adhere two recording media can be used. In view of productivity, an ultraviolet-curable or hot-melt adhesive is preferable.

[0049]

EXAMPLES The present invention will be described more specifically with reference to the following examples. Example 1 Substrate groove depth (d1) = 1750 °, groove half width (W1) =
0.25 μm, track pitch (Tr) = 0.74 μ
m, wobble frequency 32T equivalent, wobble deflection width (W
2) A solution prepared by dissolving the following compound example (I) in 2,2,3,3-tetrafluoro-1-propanol is spin-coated on a 0.6 mm-thick injection-molded polycarbonate substrate having a guide groove of 25 nm. Then, an organic dye layer having a thickness of 900 ° is formed, and then gold 1100 ° is formed by a sputtering method.
After a reflective layer having a thickness of 7 μm was formed on the reflective layer with an acrylic photopolymer, an injection molded polycarbonate flat plate having a thickness of 0.6 mm was adhered with the acrylic photopolymer to form a recording medium. The step (d2) between the land and the groove when the dye was formed was 900 °. This is applied to the relational expression of the present invention as follows (described in Table 2).

[0050]

D1 × m = 1750 × 32 = 56000 d2 × m = 900 × 32 = 28800 W1 × m = 0.25 × 32 = 8 W2 / m = 250/32 = 7.8 Tr × m = 0. 74 × 32 = 23.68

[0051]

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Example 2 Substrate groove depth (d1) = 1950 °, groove half width (W1) =
0.28 μm, track pitch (Tr) = 0.70 μ
m, wobble frequency 64T equivalent, wobble swing width (W
2) On a 0.6 mm thick injection molded polycarbonate substrate having a guide groove of = 60 nm, the following compound example (II),
A solution of (III) dissolved in 2,2,3,3-tetrafluoro-1-propanol at a weight ratio of 1: 1 is applied by spinner coating to form an organic dye layer having a thickness of 1050 °,
A reflective layer of 1000 mm of silver is provided by a sputtering method, and a protective layer of 10 μm is further provided thereon with an acrylic photopolymer, and then a 0.6 mm-thick injection-molded polycarbonate flat substrate is adhered with the acrylic photopolymer. The recording medium was used. The step (d2) between the land and the groove when the dye was formed was 950 °. This is applied to the relational expression of the present invention as follows (described in Table 2).

[0053]

D1 × m = 1950 × 64 = 124800 d2 × m = 950 × 64 = 60800 W1 × m = 0.28 × 64 = 17.92 W2 / m = 600/64 = 9.4 Tr × m = 0.7 × 64 = 44.8

[0054]

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[0055]

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Example 3 Substrate groove depth (d1) = 1550 °, groove half width (W1) =
0.20 μm, track pitch (Tr) = 0.74 μ
m, wobble frequency 16T equivalent, wobble swing width (W
2) On a 0.6 mm thick injection molded polycarbonate substrate having a guide groove of = 40 nm, the following compound example (IV)
Is dissolved in methylcyclohexane and spin-coated to form an organic dye layer having a thickness of 1100Å, then a reflective layer of 1000 金 gold is provided by a sputtering method, and a 10 µm protective layer of acrylic photopolymer is further formed thereon. After that, an injection-molded polycarbonate flat substrate having a thickness of 0.6 mm was adhered with an acrylic photopolymer to obtain a recording medium. The step (d2) between the land and the groove when the dye was formed was 860 °. This is applied to the relational expression of the present invention as follows (described in Table 2).

[0057]

D1 × m = 1550 × 16 = 24800 d2 × m = 860 × 16 = 13760 W1 × m = 0.2 × 16 = 3.2 W2 / m = 400/16 = 25 Tr × m = 0. 74 × 16 = 11.84

[0058]

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Comparative Example 1 In Example 1, the substrate groove depth, groove half width, and track pitch were exactly the same, and the wobble deflection width was equivalent to 5 nm.
The wobble frequency has an LPP cut width equivalent to 180T of 12
A recording medium was formed in exactly the same manner as in Example 1 except that the substrate under the condition of level fluctuation was used.

Example 4 Substrate groove depth (d1) = 1800 °, groove half width (W1) =
0.22 μm, track pitch (Tr) = 0.72 μ
m, wobble frequency 32T equivalent, wobble deflection width (W
2) Spinner coating with a solution prepared by dissolving the following compound example (V) in 2,2,3,3-tetrafluoro-1-propanol on an injection-molded polycarbonate substrate having a guide groove of 30 nm and a thickness of 0.6 mm. To form an organic dye layer having a thickness of 1000 °
After providing a reflective layer of 設 け, and further providing a 10 μm protective layer of acrylic photopolymer thereon, a thickness of 0.6 mm
The injection molded polycarbonate flat plate was bonded with an acrylic photopolymer to obtain a recording medium. Note that the step (d2) between the land and the groove when the dye was formed was 950.
Was Å. This is applied to the relational expression of the present invention as follows (described in Table 2).

[0061]

D1 × m = 1800 × 32 = 57600 d2 × m = 950 × 32 = 30400 W1 × m = 0.22 × 32 = 7.04 W2 / m = 300/32 = 9.4 Tr × m = 0.72 × 32 = 23.04.

[0062]

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Example 5 Substrate groove depth (d1) = 1850 °, groove half width (W1) =
0.32 μm, track pitch (Tr) = 0.74 μ
m, wobble frequency 16T equivalent, wobble swing width (W
2) On a 0.6 mm thick injection molded polycarbonate substrate having a guide groove of = 20 nm, the following compound example (V
I) and (VII) at a weight ratio of 60:40 to 2,2,3,3
-A solution dissolved in tetrafluoro-1-propanol is applied by spinner to form an organic dye layer having a thickness of 1050 °, and then a reflective layer of 1000 ° of silver is provided by a sputtering method, and an acrylic photopolymer is further formed thereon. 10
After a protective layer having a thickness of μm was provided, an injection-molded polycarbonate flat substrate having a thickness of 0.6 mm was bonded with an acrylic photopolymer to obtain a recording medium. The step (d2) between the land and the groove when the dye was formed was 890 °.
This is applied to the relational expression of the present invention as follows (described in Table 2).

[0064]

D1 × m = 1850 × 16 = 29600 d2 × m = 890 × 16 = 14240 W1 × m = 0.32 × 16 = 5.12 W2 / m = 200/16 = 12.5 Tr × m = 0.74 × 16 = 11.84

[0065]

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[0066]

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Example 6 Substrate groove depth (d1) = 1700 °, groove half width (W1) =
0.17 μm, track pitch (Tr) = 0.74 μ
m, wobble frequency 96T equivalent, wobble swing width (W
2) On a 0.6 mm thick injection molded polycarbonate substrate having a guide groove of = 50 nm, the following compound example (IV)
Is dissolved in methylcyclohexane and spin-coated to form an organic dye layer having a thickness of 1100Å, then a reflective layer of 1000 金 gold is provided by a sputtering method, and a 10 µm protective layer of acrylic photopolymer is further formed thereon. After that, an injection-molded polycarbonate flat substrate having a thickness of 0.6 mm was adhered with an acrylic photopolymer to obtain a recording medium. The step (d2) between the land and the groove when the dye was formed was 890 °. This is applied to the relational expression of the present invention as follows (described in Table 2).

[0068]

D1 × m = 1700 × 96 = 163200 d2 × m = 890 × 96 = 85440 W1 × m = 0.17 × 96 = 16.32 W2 / m = 500/96 = 5.2 Tr × m = 0.74 × 96 = 71.04

[0069]

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Comparative Example 2 In Example 5, the substrate groove depth, the half width, and the track pitch were exactly the same, the wobble swing width was equivalent to 5 nm, and the wobble frequency was 190T, the LPP cut width was equivalent to 12 levels. A recording medium was formed in exactly the same manner as in Example 5, except that a substrate was used.

<Recording Conditions> The optical recording media obtained in Examples 1 to 3 and Comparative Example 1 were subjected to an oscillation wavelength of 635 nm and a beam diameter of 0.9.
EFM signals (linear velocity: 3.5 m / sec.) are applied to the bottom while tracking using a semiconductor laser beam of μm.
Recording is performed with a strategy and recording power that minimizes Jitter, and these recording positions are set to an oscillation wavelength of 649 n.
The reproduction was performed by adjusting the equalizer gain so that the Bottom Jitter became 8.0% with 0.3 mW of continuous light of m, and the PI Error at that time was measured. Also,
Regarding the disc of Comparative Example 1, Bands whose LPPb values were near 0.12, 0.20, and 0.36, respectively, were selected, and the LPP block error rate at that time was also measured by a recording pickup. Further, the semiconductor laser light having an oscillation wavelength of 657 nm and a beam diameter of 0.85 μm was used for the optical recording media obtained in Examples 4 to 6 and Comparative Example 2, and an EFM signal (linear velocity of 3.5 m / sec.) Was used while tracking. To B
Recording is performed with a strategy and a recording power that minimizes the Jitter, and these recording positions are determined by Bottom Ji with a continuous light of 0.3 mW having an oscillation wavelength of 649 nm.
The reproduction was performed by adjusting the equalizer gain so that the ter became 8.0%, and the PI Error at that time was measured. In addition, with respect to the disk of Comparative Example 1, the LPPb values of B near 0.12, 0.22, and 0.36 respectively.
and and select LP with recording pickup at that time
The P block error rate was also measured. Table 1 shows the results.

[0072]

[Table 1]

[0073]

[Table 2]

[0074]

As is apparent from the detailed and specific description, according to the present invention, a DVD medium having good productivity can be obtained, and it is simpler than the land prepit format used in DVD-R. The data part can be efficiently added in a high-frequency wobble format that can be manufactured at a high speed.
There is an excellent effect that a recording medium in almost the same format as that of the DC-RW can be provided.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a general write-once optical recording medium of the present invention.

FIG. 2 is a diagram showing a configuration of an optical recording medium for CD-R of the present invention.

FIG. 3 is a diagram showing a configuration of an optical recording medium for DVD-R of the present invention.

[Explanation of symbols]

 Reference Signs List 1 substrate (first substrate) 2 recording layer (organic dye layer) 3 undercoat layer 4 protective layer 5 hard coat layer 6 metal reflective layer 7 protective substrate (second substrate) 8 adhesive layer

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification FI FI Theme Court ゛ (Reference) G11B 7/24 538 G11B 7/24 538E B41M 5/26 B41M 5/26 Y (72) Inventor Sasato Noboru Tokyo 1-3-6 Nakamagome, Tokyo Ota-ku, Ricoh Co., Ltd. (72) Inventor Tsutomu Tsutomu 1-3-6 Nakamagome, Ota-ku, Tokyo Ricoh Co., Ltd. (72) Yasunobu Ueno, Naka, Ota-ku, Tokyo 1-3-6, Magome, Ricoh Co., Ltd. (72) Inventor Yasuhiro Higashi 1-3-6, Nakamagome, Ota-ku, Tokyo F-term in Ricoh Co., Ltd. (Reference) 2H111 EA03 EA12 EA25 EA48 FA01 FA12 FA23 FA39 FB42 FB48 5D029 JA04 JC06 JC11 KB03 MA13 WA02 WB11 WB17 WC03

Claims (13)

[Claims] 1. An optical recording medium comprising a recording layer provided on a substrate and a reflection layer as required, wherein the substrate has a wobble having a frequency (period length) of 4T to 96T, and a recording / reproducing wavelength as the recording layer. The refractive index n of the recording layer single layer with respect to light in the wavelength range of ± 5 nm is 1.5 ≦ n ≦ 3.0, and the extinction coefficient k
Is an optical recording medium having an organic dye film satisfying 0.02 ≦ k ≦ 0.2, where 4000 ≦ d1 × m ≦ 2400 when the substrate groove depth d1 (Å) and the wobble frequency m (T) are set.
00. An optical recording medium characterized by being 00. 2. When the step between the land and the groove when the dye film is formed is d2 (Å), 1200 ≦ d
2. The structure according to claim 1, wherein 2 × m ≦ 160000.
An optical recording medium according to claim 1. 3. The optical recording medium according to claim 1, wherein, when the half width of the groove of the substrate is W1 (μm), 0.7 ≦ W1 × m ≦ 40. 4. The wobble swing width of the substrate is W2
The optical recording medium according to claim 1, wherein, when (Å) is satisfied, 2 ≦ W2 / m ≦ 500. 5. The track pitch of the substrate is Tr (μ
5. The optical recording medium according to claim 1, wherein, when m), 2 ≦ Tr × m ≦ 80. 6. The wobble amplitude Wo and the push-pull amplitude P
P (Wo / PP) is 0.1 ≦ Wo / PP ≦ 0.
The optical recording medium according to any one of claims 1 to 5, wherein the optical recording medium is within the range of (4). 7. The method according to claim 1, wherein the organic dye in the recording layer contains at least one of a metal chelate dye, a polymethine dye, a squarylium dye, and an azaannulene dye. An optical recording medium according to claim 1. 8. The light according to claim 1, wherein the metal chelate dye in the recording layer is any one of an azo metal chelate dye, a formazan metal chelate dye, and a dipyrromethene metal chelate dye. recoding media. 9. The optical recording medium according to claim 7, wherein the metal of the metal chelate dye in the recording layer is nickel, copper, cobalt, manganese, or vanadium oxide. 10. The recording layer according to claim 7, wherein the polymethine dye is a trimethine cyanine dye, and the azaannulene dye is a tetraazaporphyrin dye.
An optical recording medium according to claim 1. 11. The decomposition start temperature of the recording layer is 360
The optical recording medium according to any one of claims 1 to 10, wherein the temperature is lower than or equal to ° C. 12. When a reflective layer is required, the reflective layer is made of gold,
12. The optical recording medium according to claim 1, wherein the optical recording medium is silver, aluminum, or an alloy with another metal containing these as a main component. 13. The optical recording medium according to claim 1, wherein a recording wavelength is from 600 to 720 nm.