JPH08306074A - Optical recording medium - Google Patents

Abstract

PURPOSE: To obtain an optical recording medium having a mask layer which is formable by using a vacuum vapor deposition method and is suitable for high-density recording and/or reproducing. CONSTITUTION: This optical recording medium has the mask layer 3 which is changed in light transmittance by a temp. change resulted from the irradiation with light on a light transmissive substrate formed with micropit arrays or concentric or spiral guide grooves with which optical reading-out is possible. The effective spot diameter of a laser beam for reproduction is diminished by utilizing the change in the light transmittance of the mask layer 3. The mask layer 3 is composed essentially of a thermochromic material which is reversibly changed on the light transmittance only by the two components of an electron donative color developing compd. and electron receptive color developing agent and is so formed that its absorption peak exists at a wavelength region of 580 to 720nm.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical recording medium for recording and / or reproducing at high density, and more particularly, to an effective spot of irradiation laser light using a light transmittance variable medium whose light transmittance changes according to temperature changes. The present invention relates to an optical recording medium for recording and / or reproducing information at high density by making a system small.

[0002]

2. Description of the Related Art In recent years, increasing the capacity of optical disks has been studied and various proposals have been made. In principle, there is no limit in improving the density of an optical disk because it is possible to form recording marks smaller than the light spot diameter by controlling the laser light power during recording. However, there is a limit value that the light spot diameter when the laser light is narrowed down by a lens cannot be narrowed down to a certain value or less, and the densification of an optical disk depends on how to reduce the reproduction laser spot. The repetition wavelength (recording wavelength) of the recording mark at the reproduction limit is given by λ / 2NA. Here, λ is the wavelength of light, and NA is the numerical aperture of the lens.

It is understood that in order to identify and reproduce a recording mark having a shorter recording wavelength, it is sufficient to reproduce with a light having a short wavelength λ or use a lens having a large numerical aperture NA. However, it is technically difficult to shorten the wavelength of the semiconductor laser used for reproduction, and it is not easy to incorporate a lens having a large numerical aperture NA into the optical disc device.

Therefore, as shown in FIG. 3, when the temperature rises due to the irradiation of light, the absorbance decreases and the light transmittance increases as the temperature rises. Further, the laser light passes through and is cooled again. By providing a layer of a substance (hereinafter referred to as a light transmittance variable medium) that increases the absorbance and decreases the light transmittance in the optical disk, information is recorded at high density on the optical disk or information recorded at high density is reproduced. A method called "super resolution of disk" has been conventionally known.

The light intensity distribution of the laser light used for information recording / reproduction usually shows a Gaussian distribution, and the temperature distribution is also a distribution close to this. When such a laser beam is irradiated onto the variable light transmittance medium, as shown in FIG. 4, only the central portion A where the temperature in the irradiation spot has risen becomes transparent and the other portion B in the light spot is masked. The so-called disc super-resolution effect occurs. At this time, the effective spot diameter of the laser light transmitted through the central portion A is smaller than the irradiation spot diameter of the irradiation laser light, as shown in FIG. By providing the variable light transmittance medium that causes the disc super-resolution effect in layers on the optical disk (hereinafter, this variable light transmittance medium layer is referred to as a mask layer), the light transmission in the spot of the laser light to be irradiated is transmitted. Allows only the light of high ratio to pass,
Since the light in the irradiation spot having a low light transmittance is masked, crosstalk between adjacent tracks and between adjacent pits can be prevented.

The mask layer is required to have a high speed of changing / restoring the light transmittance with respect to the irradiation of the laser beam for optical recording / reproducing. That is, the light transmittance increases while the irradiation laser light passes through the rotating optical disc, and the light transmittance needs to be restored before the irradiation laser light passes again. As a light transmittance variable medium satisfying such conditions, for example, as proposed in Japanese Patent Application No. 6-261925, it is composed of two components of an electron donating color developing compound and an electron accepting developer. There is something.

In the above-mentioned two-component type thermochromic material, coloring, decoloring and discoloration occur due to the exchange of electrons between the electron-donating color developing compound and the electron-accepting positive color developer. By selecting the structure of the electron-donating color developing compound or the electron-accepting color developer, the light absorption wavelength of the variable light transmittance medium, and the color development /
The erasing / discoloring temperature can be set arbitrarily.

However, the two-component thermochromic material as described above may have a low coloring density at the wavelength of the laser used depending on the electron donative coloring compound. Therefore, an extremely thick film thickness is required in order to obtain the absorbance required to cause the disc super-resolution. If the film thickness of the mask layer becomes thick, it becomes difficult to form a transparent film, so that the S / N ratio of the reproduced signal waveform deteriorates.
There is a problem that the mask layer does not become transparent in the thickness direction.

On the other hand, in order to form the above-mentioned two-component thermochromic material on the optical disk, the spin coating method suitable for forming a thick film is advantageous in view of productivity and the like. However, the spin coating method is a method in which a solution-like coating material is dropped on a rotated optical disk substrate and is evenly applied on the optical disk substrate by centrifugal force due to rotation, and therefore a uniform film is formed on a convex optical disk. Is difficult to form. That is, in the formation method using the spin coating method, the film thickness of the pit or guide groove that is a concave portion and the substrate flat surface portion (land portion) that is a convex portion becomes uneven,
It is not suitable for forming a mask layer on an uneven optical disk substrate. When the film thickness becomes non-uniform in this way,
The optical path length, optical characteristics, thermal characteristics, etc. of the reproduction laser light (or recording laser light) at the convex portion change, and it becomes impossible to obtain an accurate reproduction signal. In addition, since the pits or guide grooves of an optical disc recorded with high density are smaller than those used in currently practically used optical discs, if the mask layer is formed by using the spin coat method, the pit Also, the guide groove may be filled, and in such a case, reproduction becomes impossible.

Therefore, as a thin film forming method other than the spin coating method, it is possible to use a vacuum vapor deposition method which is excellent in film thickness controllability. This vacuum vapor deposition method is widely used, for example, in the manufacture of semiconductors and magnetic recording media. It is expected that a mask layer having a uniform film thickness can be formed on the optical disk substrate by using this vacuum deposition method.

[0011]

However, in the above-mentioned vacuum vapor deposition method, the substance (metal, semiconductor, etc.) to be formed is heated and evaporated, and the vaporized atoms or molecules are applied to the substance to form a film on the surface thereof. Since it is a method, when forming a thin film of an organic compound which is generally a material for the mask layer and is easily decomposed by high heat, there are restrictions on the material side, and it is not used as a means for forming a thin film. There is a problem of being few. The present invention has been made by paying attention to the above points, and is an optical recording medium that can be formed using a vacuum deposition method and that has a mask layer suitable for high-density recording and / or reproduction. The purpose is to provide.

[0012]

As means for achieving the above object, according to the present invention, an optically readable fine pit row or a light-transmissive substrate on which concentric or spiral guide grooves are formed. , A light having a mask layer whose light transmittance reversibly changes due to temperature change due to light irradiation, and which uses the light transmittance change of this mask layer to reduce the effective spot diameter of the reproducing laser light. The mask layer of the recording medium is mainly composed of a thermochromic material whose light transmittance reversibly changes only with two components, an electron-donating color developing compound and an electron-accepting developer, and has an absorption peak of 580 to 7
An optical recording medium having a wavelength range of 20 nm is obtained. In the optical recording medium of the present invention, as the electron-donating color-forming compound which is the first component constituting the mask layer, there are fluoran compounds or phthalide compounds represented by the following general formulas (I) to (IX). Preference is given to using.

[0013]

[Chemical 13]

In the formula, R ₁ , R ₂ , R ₃ and R ₄ each independently represent a hydrogen atom, an unsubstituted or substituted alkyl group, an unsubstituted or substituted phenyl group, and R ₁ , R ₂ , R ₃ And R ₄ may form a heterocycle together with the nitrogen atom which is connected to and bonded to each other. X ₁ and X ₂ are a hydrogen atom, an unsubstituted or substituted alkyl group, an unsubstituted or substituted phenyl group, an unsubstituted or substituted alkoxy group, an unsubstituted or substituted phenyloxy group, an unsubstituted or substituted alkylthio group,
Unsubstituted or substituted phenylthio group, dialkylamino group and halogen atom are shown. Ring A ₁ represents a substituent represented by the following structural formula (I):

[0015]

Embedded image

In the formula, Z ₁ represents a hydrogen atom, an unsubstituted or substituted alkyl group, an unsubstituted or substituted alkoxy group, a dialkylamino group, or a halogen atom, and n ₁ is 1
Indicates an integer of ˜4.

[0017]

[Chemical 15]

In the formula, R ₅ , R ₆ , R ₇ and R ₈ each independently represent a hydrogen atom, an unsubstituted or substituted alkyl group, an unsubstituted or substituted phenyl group, and R ₅ and R ₆ are linked to each other. And a heterocyclic ring may be formed together with the bonded nitrogen atom. X ₃ , X ₄ and X ₅ are hydrogen atoms, unsubstituted or substituted alkyl groups, unsubstituted or substituted alkoxy groups, unsubstituted or substituted phenyloxy groups, unsubstituted or substituted alkylthio groups, unsubstituted or substituted phenylthio groups, dialkylamino Group and halogen atom. Ring A ₂
Represents a substituent represented by the following structural formula (I):

[0019]

Embedded image

In the formula, Z ₂ represents a hydrogen atom, an unsubstituted or substituted alkyl group, an unsubstituted or substituted alkoxy group, a dialkylamino group, or a halogen atom, and n ₂ is 1
Indicates an integer of ˜4.

[0021]

[Chemical 17]

In the formula, R ₉ , R ₁₀ , R ₁₁ , R ₁₂ , R ₁₃ and R ₁₄ represent a hydrogen atom, an unsubstituted or substituted alkyl group, an unsubstituted or substituted alkoxyalkyl group, an unsubstituted or substituted phenyl group. Also, R ₉ and R ₁₀ may form a heterocycle together with a nitrogen atom which is connected to and bonded to each other. X ₆ , X ₇ , X ₈ , X ₉ and X ₁₀ are hydrogen atoms, unsubstituted or substituted alkyl groups, unsubstituted or substituted alkoxy groups, unsubstituted or substituted phenyloxy groups, unsubstituted or substituted alkylthio groups, unsubstituted or A substituted phenylthio group, a dialkylamino group and a halogen atom are shown.
Ring A ₃ represents a substituent represented by the following structural formula (III):

[0023]

Embedded image

In the formula, Z ₃ represents a hydrogen atom, an unsubstituted or substituted alkyl group, an unsubstituted or substituted alkoxy group, a dialkylamino group, or a halogen atom, and n ₃ is 1
Indicates an integer of ˜4. However, 3- [1,1-bis (1-ethyl-2-methylindol-3-yl) -ethylene-
2-yl] -3- (4-diethylaminophenyl) phthalide is excluded.

[0025]

[Chemical 19]

[0026] In the formula, R _15, R ₁₆ is a hydrogen atom, an unsubstituted or substituted alkyl group, unsubstituted or substituted alkoxyalkyl group, an unsubstituted or substituted phenyl group, also, R1 ₅ and R ₁₆ are linked to each other A heterocycle may be formed with the nitrogen atom to which it is bonded. R ₁₇ is 2 having 2 to 6 carbon atoms
Represents a monovalent hydrocarbon group.

[0027]

Embedded image

[0028] In the formula, R _18, R ₁₉ is a hydrogen atom, an unsubstituted or substituted alkyl group, unsubstituted or substituted alkoxyalkyl group, an unsubstituted or substituted phenyl group, also, R1 ₈ and R ₁₉ are linked to each other A heterocycle may be formed with the nitrogen atom to which it is bonded. R ₂₀ represents a hydrogen atom, an unsubstituted or substituted alkyl group, an unsubstituted or substituted benzyl group.

[0029]

[Chemical 21]

In the formula, R ₂₁ and R ₂₂ represent a hydrogen atom, an unsubstituted or substituted alkyl group, an unsubstituted or substituted alkoxyalkyl group, an unsubstituted or substituted phenyl group, and R 2 ₁ and R ₂₂ are connected to each other. A heterocycle may be formed with the nitrogen atom to which it is bonded. R ₂₃ represents a hydrogen atom or an alkyl group.

[0031]

[Chemical formula 22]

[0032] In the formula, R _24, R ₂₅ is a hydrogen atom, an unsubstituted or substituted alkyl group, an unsubstituted or substituted alkoxyalkyl group, an unsubstituted or substituted phenyl group, also, R2 ₄ and R ₂₅ are linked to each other A heterocycle may be formed with the nitrogen atom to which it is bonded. R ₂₆ represents a hydrogen atom or an alkyl group.

[0033]

[Chemical formula 23]

In the formula, R ₂₇ , R ₂₈ , R ₂₉ , R ₃₀ , R ₃₁ and R ₃₂ represent a hydrogen atom, an unsubstituted or substituted alkyl group, an unsubstituted or substituted alkoxyalkyl group, an unsubstituted or substituted phenyl group. , R ₂₇ and R ₂₈ , R ₂₉ and R
₃₀ , R ₃₁ and R ₃₂ may be linked to each other to form a heterocycle together with the bonded nitrogen atom.

[0035]

[Chemical formula 24]

In the formula, R ₃₃ , R ₃₄ , R ₃₅ and R ₃₆ represent a hydrogen atom, an unsubstituted or substituted alkyl group, an unsubstituted or substituted alkoxyalkyl group, an unsubstituted or substituted phenyl group, and R ₃₃ and R ₃₄ , R ₃₅ and R ₃₆ may form a heterocycle together with the nitrogen atom which is connected to each other and bonded. Specific examples of the electron-donating color-forming compound represented by formulas (I) to (IX) of the present invention are shown below.

[0037]

Table 1 Compounds represented by the general formula (I) 3,3-bis (4-dimethylaminophenyl) -6-dimethylaminophthalide 3,3-bis (4-diethylaminophenyl) -6-diethylaminophthalide 3,3-bis (4-dimethylaminophenyl) -6-diethylaminophthalide 3,3-bis (4-di-n-butylaminophenyl)-
6-di-n-butylaminophthalide 3,3-bis (4-dimethylaminophenyl) phthalide 3,3-bis (4-diethylaminophenyl) phthalide 3,3-bis (2-methoxy-4-dimethylaminophenyl) ) Phthalide 3,3-bis (2-ethoxy-4-diethylaminophenyl) phthalide 3,3-bis (2-phenoxy-4-diethylaminophenyl) phthalide 3,3-bis (2-ethylthio-4-diethylaminophenyl) phthalide 3,3-bis (2-methyl-4-diethylaminophenyl) phthalide 3,3-bis (2-chloro-4-dimethylaminophenyl) phthalide 3,3-bis (2-chloro-4-diethylaminophenyl) phthalide 3 , 3-bis (4-diethylaminophenyl) benzo (f) phthalide 3,3-bis (4- Ethylaminophenyl) -4-azaphthalide 3,3-bis (4-diethylamino-2-methoxyphenyl) -4-azaphthalide 3,3-bis (2-ethoxy-4-diethylaminophenyl) -4-azaphthalide 3,3- Bis (2-ethoxy-4-diethylaminophenyl) -7-azaphthalide 3,3-bis (4-diethylamino-2-methylphenyl) -4-azaphthalide 3,3-bis (4-diethylamino-2-n-pentoxy Phenyl) -4-azaphthalide 3,3-bis (2-ethoxy-4-di-n-butylaminophenyl) -4-azaphthalide 3,3-bis (4-diethylamino-2-phenoxyphenyl) -4-azaphthalide 3 , 3-Bis (2-ethylthio-4-diethylaminophenyl) -4-azaphthalide 3,3-bis [ 2-Ethoxy-4- (N-ethylanilino) phenyl] -4-azaphthalide 3- (4-diethylamino-2-ethoxyphenyl)-
3- (4-diethylamino-2-methoxyphenyl)-
4-Azaphthalide 3- (2-ethoxy-4-diethylaminophenyl)-
3- [2-Ethoxy-4- (N-ethylanilino) phenyl] -4-azaphthalide 3,3-bis (4-diethylaminophenyl) -benzo (f) -4-azaphthalide 3,3-bis (4-diethylaminophenyl) ) -4,7
-Diazaphthalide 3,3-bis (4-diethylamino-2-ethoxyphenyl) -4,7-diazaphthalide 3,3-bis (4-diethylamino-2-methylphenyl) -4,7-diazaphthalide 3,3-bis ( 4-Dimethylamino-2-methylphenyl) -4,7-diazaphthalide 3,3-bis (4-diethylaminophenyl) -benzo (f) -4,9-diazaphthalide 3,3-bis (4-diethylaminophenyl) naphtho [D, e-2,3,4] -6-oxacyclohexene-
5-on

[0038]

Table 2 Compound represented by general formula (II) 3- (4-Dimethylaminophenyl) -3- (1-ethyl-2-methyl-3-indolyl) phthalide 3- (4-diethylaminophenyl) -3 -(1-Ethyl-2-methyl-3-indolyl) phthalide 3- (4-diethylaminophenyl) -3- (1,2-
Dimethyl-3-indolyl) phthalide 3- (4-di-n-propylaminophenyl) -3-
(1-Ethyl-2-methyl-3-indolyl) phthalide 3- (4-di-n-butylaminophenyl) -3- (1
-Ethyl-2-methyl-3-indolyl) phthalide 3- (4-diethylaminophenyl) -3- (1-n-
Butyl-2-methyl-3-indolyl) phthalide 3- (4-diethylaminophenyl) -3- (1-n-
Pentyl-2-methyl-3-indolyl) phthalide 3- (4-diethylaminophenyl) -3- (1-n-
Octyl-2-methyl-3-indolyl) phthalide 3- (4-diethylaminophenyl) -3- (1-ethyl-2-phenyl-3-indolyl) phthalide 3- (4-di-n-butylaminophenyl)- 3- (1
-Ethyl-2-phenyl-3-indolyl) phthalide 3- (2-ethoxy-4-diethylaminophenyl)-
3- (1-Ethyl-2-methyl-3-indolyl) phthalide 3- (4-diethylamino-2-methylphenyl) -3
-(1-Ethyl-2-methyl-3-indolyl) phthalide 3- (2-chloro-4-diethylaminophenyl) -3
-(1-Ethyl-2-methyl-3-indolyl) phthalide 3- (4-diethylamino-2-phenoxyphenyl)
-3- (1-Ethyl-2-methyl-3-indolyl) phthalide 3- (4-diethylamino-2-methylthiophenyl)
-3- (1-Ethyl-2-methyl-3-indolyl) phthalide 3- (4-Dimethylaminophenyl) -3- (1-ethyl-2-methyl-3-indolyl) benzo (f) phthalide 3- ( 4-Diethylaminophenyl) -3- (1-ethyl-2-methyl-3-indolyl) -4-azaphthalide 3- (4-diethylaminophenyl) -3- (1-methyl-2-methyl-3-indolyl)- 4-Azaphthalide 3- (2-ethoxy-4-diethylaminophenyl)-
3- (1-Ethyl-2-methyl-3-indolyl) -4
-Azaphthalide 3- (4-diethylamino-2-methylphenyl) -3
-(1-Ethyl-2-methyl-3-indolyl) -4-
Azaphthalide 3- (4-diethylamino-2-methylphenyl) -3
-(1,2-Dimethyl-3-indolyl) -4-azaphthalide 3- [2-ethoxy-4- (N-ethylanilino) phenyl] -3- (1,2-dimethyl-3-indolyl)-
4-Azaphthalide 3- (4-diethylaminophenyl) -3- (1-ethyl-2-methyl-3-indolyl) -benzo (f) -4
-Azaphthalide 3- (2-ethoxy-4-diethylaminophenyl)-
3- (1-ethyl-2-methyl-3-indolyl)-
4,7-Diazaphthalide 3- (4-dimethylaminophenyl) -3- (1-ethyl-2-methyl-3-indolyl) -4,7-diazaphthalide 3- (4-di-n-butylaminophenyl)- 3- (1
-Ethyl-2-methyl-3-indolyl) -4,7-diazaphthalide 3- (4-dimethylaminophenyl) -3- (1-ethyl-2-methyl-3-indolyl) -benzo (f)-
4,7-Diazaphthalide 3- (4-dimethylaminophenyl) -3- (1-ethyl-2-methyl-3-indolyl) naphtho [d, e-
2,3,4] -6-Oxacyclohexen-5-one

[0039]

Table 3 Compound represented by general formula (III) 3- [1,1-bis (1-ethyl-2-methylindol-3-yl) ethylene-2-yl] -3- (4-dimethylamino Phenyl) phthalide 3- [1,1-bis (1-ethyl-2-methylindol-3-yl) ethylene-2-yl] -3- (4-di-
n-Propylaminophenyl) phthalide 3- [1,1-bis (1-ethyl-2-methylindol-3-yl) ethylene-2-yl] -3- (4-di-
n-Butylaminophenyl) phthalide 3- [1,1-bis (1-ethyl-2-methylindol-3-yl) ethylene-2-yl] -3- (4-pyrrolidinophenyl) phthalide 3- [1 , 1-Bis (1-ethyl-2-methylindol-3-yl) ethylene-2-yl] -3- [4- (N
-Methyl-N-cyclohexylamino) phenyl] phthalide 3- [1,1-bis (1-ethyl-2-methylindol-3-yl) ethylene-2-yl] -3- [4- (N
-Ethylanilino) phenyl] phthalide 3- [1,1-bis (1-ethyl-2-methylindol-3-yl) ethylene-2-yl] -3- (2-methyl-4-diethylaminophenyl) phthalide 3- [1,1-Bis (1-ethyl-2-methylindol-3-yl) ethylene-2-yl] -3- (2-ethoxy-4-diethylaminophenyl) phthalide 3- [1,1-bis (1 -N-Butyl-2-methylindol-3-yl) ethylene-2-yl] -3- (4-
Diethylaminophenyl) phthalide 3- [1,1-bis (1-n-octyl-2-methylindol-3-yl) ethylene-2-yl] -3- (4
-Diethylaminophenyl) phthalide 3- [1,1-bis (1-ethyl-2-phenylindol-3-yl) ethylene-2-yl] -3- (4-diethylaminophenyl) phthalide 3- [1,1- Bis (1-ethyl-2-phenylindol-3-yl) ethylene-2-yl] -3- (4-dimethylaminophenyl) phthalide 3- [1,1-bis (1-ethyl-2-phenylindole- 3-yl) ethylene-2-yl] -3- (4-di-n-propylaminophenyl) phthalide 3- [1,1-bis (1-ethyl-2-phenylindol-3-yl) ethylene-2 -Yl] -3- (4-di-n-butylaminophenyl) phthalide 3- [1,1-bis (1-ethyl-2-phenylindol-3-yl) ethylene-2-yl] -3- ( -Methyl-4-diethylaminophenyl) phthalide 3- [1,1-bis (1-ethyl-2-phenylindol-3-yl) ethylene-2-yl] -3- (2-ethoxy-4-diethylaminophenyl) Phthalide 3- [1,1-bis (1-n-butyl-2-phenylindol-3-yl) ethylene-2-yl] -3- (4
-Diethylaminophenyl) phthalide 3- [1- (1-ethyl-2-methylindole-3-
Yl) -1- (1-ethyl-2-phenylindole-
3-yl) -ethylene-2-yl] -3- (4-diethylaminophenyl) phthalide 3- [1,1-bis (1-ethyl-2-methylindol-3-yl) ethylene-2-yl]- 3- (4-Diethylaminophenyl) benzo (f) phthalide 3- [1,1-bis (1-ethyl-2-methylindol-3-yl) ethylene-2-yl] -3- (4-diethylaminophenyl) Naft [d, e-2,3,4]-
6-oxacyclohexen-5-one

[0040]

Table 4 Compound represented by general formula (IV) 2- (1,2,3,4-tetrahydroquinolin-1-yl) -6-diethylaminofluorane 2- (1,2,3,4-tetrahydro Quinolin-1-yl) -6-di-n-propylaminofluorane 2- (1,2,3,4-tetrahydroquinolin-1-yl) -6-di-n-butylaminofluorane 2- (1 , 2,3,4-Tetrahydroquinolin-1-yl) -6-di-n-pentylaminofluorane 2- (1,2,3,4-tetrahydroquinolin-1-yl) -6-di-n- Octylaminofluorane 2- (1,2,3,4-tetrahydroquinolin-1-yl) -6-di-isobutylaminofluorane 2- (1,2,3,4-tetrahydroquinolin-1-yl)- 6-di-sec-butylamino Fluoran 2- (1,2,3,4-tetrahydroquinolin-1-yl) -6- (N-ethyl-N-isopentylamino) fluorane 2- (1,2,3,4-tetrahydroquinoline-1- Yl) -6- (N-ethyl-N-isopropylamino) fluorane 2- (1,2,3,4-tetrahydroquinolin-1-yl) -6- (N-cyclohexyl-N-methylamino)
Fluoran 2- (1,2,3,4-tetrahydroquinolin-1-yl) -6- (N-ethyl-N-ethoxypropylamino) fluorane 2- (1,2,3,4-tetrahydroquinoline-1- Yl) -6- (N-ethyl-N-phenylamino) fluorane 2- (1,2,3,4-tetrahydroquinolin-1-yl) -6-piperidinoaminofluorane 2- (1,2,2) 3,4-Tetrahydroquinolin-1-yl) -6- (N-ethyl-N-tetrahydrofurfurylamino) fluorane 2- (1,2,3,4-tetrahydroquinolin-1-yl) -6- (N -Ethyl-N-sec-butylamino)
Fluoran 2- (1,2,3,4-tetrahydroquinolin-1-yl) -6-N-ethylaminofluoran 2- (2-methyl-1,2,3,4-tetrahydroquinolin-1-yl) -6-Diethylaminofluorane 2- (2,3-dimethyl-1,2,3,4-tetrahydroquinolin-1-yl) -6-diethylaminofluorane 2- (2,3,4-trimethyl-1,2) , 3,4-Tetrahydroquinolin-1-yl) -6-diethylaminofluorane 2- (3-ethyl-1,2,3,4-tetrahydroquinolin-1-yl) -6-diethylaminofluorane 2- (indoline -1-yl) -6- (N-ethyl-N
-Isopentylamino) fluorane 2- (indoline-1-yl) -6- (N-cyclohexyl-N-methylamino) fluorane 2- (indoline-1-yl) -6- (N-ethyl-N)
-Ethoxypropylamino) fluorane 2- (indoline-1-yl) -6- (N-ethyl-N
-Phenylamino) fluorane 2- (2-methylindoline-1-yl) -6-diethylaminofluorane 2- (2,3-dimethylindoline-1-yl) -6-
(N-Ethyl-N-tetrahydrofurfurylamino) fluorane 2- (2,3-dimethylindoline-1-yl) -6-
Diethylaminofluorane 2- (indoline-1-yl) -6-piperidinoaminofluorane

[0041]

[Table 5] Compound represented by general formula (V) 10-Dimethylamino-2-methylbenzo [1,4] thiazino [3,2-b] fluorane 10-Dimethylamino-2-ethylbenzo [1,4] thiazino [3,2-b] Fluorane 10-diethylamino-2-ethylbenzo [1,4] thiazino [3,2-b] fluorane 10-di-n-propylamino-2-ethylbenzo [1,4] thiazino [3,3] 2-b] fluorane 10-di-n-butylamino-2-ethylbenzo [1,
4] thiazino [3,2-b] fluorane 10-diisobutylamino-2-ethylbenzo [1,
4] Thiazino [3,2-b] fluorane 10- (N-ethyl-N-isopentylamino) 2-ethylbenzo [1,4] thiazino [3,2-b] fluorane 10-di-n-octylamino- 2-Ethylbenzo [1,4] thiazino [3,2-b] fluorane 10- (N-cyclohexyl-N-methylamino) 2-
Ethylbenzo [1,4] thiazino [3,2-b] fluorane 10- (N-ethoxypropyl-N-ethylamino) 2
-Ethylbenzo [1,4] thiazino [3,2-b] fluorane 10-N-ethylanilino-2-ethylbenzo [1,
4] Thiazino [3,2-b] fluorane 2-ethylbenzo-10-piperidino [1,4] thiazino [3,2-b] fluorane 2-ethyl-10- [N-ethyl- (4-N-ethylanilino) Anilino] benzo [3,2-b] fluorane 10-dimethylamino-2-n-propylbenzo [1,
4] thiazino [3,2-b] fluorane 10-dimethylamino-2-n-butylbenzo [1,
4] Thiazino [3,2-b] fluorane 10-N-ethylanilino-2-n-octylbenzo [1,4] thiazino [3,2-b] fluorane

[0042]

Table 6 Compounds represented by general formula (VI) 2-anilino-6-diethylaminofluorane 2-anilino-6-di-n-propylaminofluorane 2-anilino-6-di-n-butylaminofluor Oran 2-anilino-6-di-n-pentylaminofluorane 2-anilino-6-di-n-octylaminofluorane 2-anilino-6-di-isobutylaminofluorane 2-anilino-6-di-sec -Butylaminofluorane 2-anilino-6- (N-ethyl-N-isopentylamino) fluorane 2-anilino-6- (N-ethyl-N-isopropylamino) fluorane 2-anilino-6- (N-cyclohexyl) -N-methylamino) fluorane 2-anilino-6- (N-ethyl-N-ethoxypropylamino) fluorane 2-anili -6- (N-Ethyl-N-phenylamino) fluorane 2-anilino-6-piperidinoaminofluorane 2-anilino-6- (N-ethyl-N-tetrahydrofurfurylamino) fluorane 2-anilino-6 -(N-Ethyl-N-sec-butylamino) fluorane 2-anilino-6-N-ethylaminofluorane 2- (2-methylanilino) -6-diethylaminofluorane 2- (3-methylanilino) -6-diethylamino Fluorane 2- (4-methylanilino) -6-diethylaminofluorane 2- (2,3-dimethylanilino) -6-diethylaminofluorane 2- (2,4-dimethylanilino) -6-diethylaminofluorane 2 -(2,5-Dimethylanilino) -6-diethylaminofluorane 2- (2,6-dimethyl Anilino) -6-diethylaminofluorane 2- (3,5-dimethylanilino) -6-diethylaminofluorane 2- (3,4-dimethylanilino) -6-diethylaminofluorane 2- (N-methylanilino)- 6-Diethylaminofluorane 2- (N-ethylanilino) -6-diethylaminofluorane 2- (Nn-propylanilino) -6-diethylaminofluorane 2- (Nn-butylanilino) -6-diethylaminofluorane 2- (N-n-pentylanilino) -6-diethylaminofluorane 2- (N-n-hexylanilino) -6-diethylaminofluorane 2- (Nn-heptylanilino) -6-diethylaminofluorane 2 -(N-n-octylanilino) -6-diethylaminofluorane 2- (N-beta) Jiruanirino) -6-diethylaminofluoran

[0043]

[Table 7] Compound represented by general formula (VII) 2- (dibenzylamino) -6-diethylaminofluorane 2- (dibenzylamino) -6-di-n-propylaminofluorane 2- (dibenzyl Amino) -6-di-n-butylaminofluorane 2- (dibenzylamino) -6-di-n-pentylaminofluorane 2- (dibenzylamino) -6-di-n-octylaminofluorane 2 -(Dibenzylamino) -6-di-isobutylaminofluorane 2- (dibenzylamino) -6-di-sec-butylaminofluorane 2- (dibenzylamino) -6- (N-ethyl-N- Isopentylamino) fluorane 2- (dibenzylamino) -6- (N-ethyl-N-isopropylamino) fluorane 2- (dibenzylamino) -6- (N-sic) Lohexyl-N-methylamino) fluorane 2- (dibenzylamino) -6- (N-ethyl-N-ethoxypropylamino) fluorane 2- (dibenzylamino) -6- (N-ethyl-N-phenylamino) Fluorane 2- (dibenzylamino) -6-piperidinoaminofluorane 2- (dibenzylamino) -6- (N-ethyl-N-tetrahydrofurfurylamino) fluorane 2- (dibenzylamino) -6- (N-ethyl-N-s
ec-Butylamino) fluorane 2- (dibenzylamino) -6-N-ethylaminofluorane 2- [di- (2-methylbenzylamino)]-6-diethylaminofluorane 2- [di- (3-methyl Benzylamino)]-6-diethylaminofluorane 2- [di- (4-methylbenzylamino)]-6-diethylaminofluorane 2- [di- (2,3-dimethylbenzylamino)]-6
-Diethylaminofluorane 2- [di- (2,4-methylbenzylamino)]-6-
Diethylaminofluorane 2- [di- (2,5-methylbenzylamino)]-6-
Diethylaminofluorane 2- [di- (2,6-methylbenzylamino)]-6-
Diethylaminofluorane 2- [di- (3,4-methylbenzylamino)]-6-
Diethylaminofluorane 2- [di- (3,5-methylbenzylamino)]-6-
Diethylaminofluorane

[0044]

[Table 8] Compound represented by the general formula (VIII) 3,6,6'-tris (dimethylamino) spiro [fluorene-3,9'-phthalide] 3,6,6'-tris (di-n-) Propylamino) spiro [fluorene-3,9'-phthalide] 3,6,6'-tris (di-n-butylamino) spiro [fluorene-3,9'-phthalide] 6'-diethylamino-3,6- Bis (dimethylamino) spiro [fluorene-3,9'-phthalide] 3,6-bis (diethylamino) -6'-dimethylaminospiro [fluorene-3,9'-phthalide] 3-di-n-butylamino- 6,6'-Bis (dimethylamino) spiro [fluorene-3,9'-phthalide] 3-diethylamino-6-di-n-butylamino-6 '
-Dimethylaminospiro [fluorene-3,9'-phthalide] 3,6-bis (dimethylamino) -6'-diethylaminospiro [fluorene-3,9'-phthalide] 3,6'-bis (diethylamino) -6 -Dimethylaminospiro [fluorene-3,9'-phthalide] 3-di-n-butylamino-6'-diethylamino-6
-Dimethylaminospiro [fluorene-3,9'-phthalide] 3,6,6'-tris (diethylamino) spiro [fluorene-3,9'-phthalide] 3-di-n-butylamino-6,6'- Bis (diethylamino) spiro [fluorene-3,9'-phthalide] 3,6-bis (dimethylamino) -6'-n-butylaminospiro [fluorene-3,9'-phthalide] 6'-di-n- Butylamino-3-diethylamino-6
-Dimethylaminospiro [fluorene-3,9'-phthalide] 3-dibenzylamino-6,6'-bis (dimethylamino) spiro [fluorene-3,9'-phthalide] 3-piperidino-6,6'- Bis (dimethylamino) spiro [fluorene-3,9'-phthalide] 3-methylamino-6,6'-bis (dimethylamino)
Spiro [fluorene-3,9'-phthalide] 3-pyrrolidino-6,6'-bis (dimethylamino) spiro [fluorene-3,9'-phthalide] 3-N-cyclohexyl-N-methylamino-6,6 '
-Bis (dimethylamino) spiro [fluorene-3,
9'-phthalide] 3-piperazino-6,6'-bis (dimethylamino) spiro [fluorene-3,9'-phthalide] 3-N-ethylaniline-6,6'-bis (dimethylamino) spiro [fluorene -3,9'-phthalide] 3-N-ethoxypropyl-N-ethylamino-6,6
6'-bis (dimethylamino) spiro [fluorene-
3,9'-phthalide]

[0045]

Table 9 Compounds represented by the general formula (IX) 2,6-bis (diethylamino) thiofluorane 6-diethylamino-2-dimethylamino-3-methylthiofluorane 6-diethylamino-2-n-octylaminothiofluorane 7-chloro-6-diethylamino-2-isopentylaminothiofluorane 6-anilino-2-diethylaminothiofluorane 2-ethylamino-6-diethylaminothiofluorane 2,6-bisethylamino-3-methylthio Fluoran 6-diethylamino-2-piperidinothiofluorane 2-anilino-6-dimethylaminothiofluorane 2-anilino-6-diethylaminothiofluorane 2-anilino-6-di-n-propylaminothiofluorane 2 -Anilino-6-di-n-butylaminothiofluor 2-anilino-6-di-n-octylaminothiofluorane 2-anilino-6- (N-cyclohexyl-N-methylamino) thiofluorane 2-anilino-6- (N-ethyl-N-isopentylamino) Thiofluorane 2-anilino-6- (N-ethylanilino) thiofluorane 2-anilino-6-diethylamino-3-methylthiofluorane 2- (4-anilino) anilino-6-diethylaminothiofluorane 2- (4-dimethylamino) anilino -6-Diethylaminothiofluorane

All of these electron-donating color-developing compounds, when combined with an electron-accepting developer described later, have large light absorption in the wavelength range of about 600 nm and exhibit good disc super-resolution. .

The structure of the optical recording medium of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a diagram showing the structure of an optical recording medium of the present invention, for example, an optical disc. FIG. 1 (A) shows a read-only optical disc 1 and FIG. 1 (B) shows a recordable optical disc 11. It is shown.

In FIG. 1A, a read-only optical disc 1 is irradiated from the lower side of the light-transmissive substrate 2 on which optically readable pits 2A are formed and the above-mentioned disc super-resolution effect. A mask layer 3 for reducing the effective spot diameter of the laser light, a reflective layer 4 made of aluminum or the like, and a protective film layer 5 made of a UV curable resin or the like are laminated in this order.

Further, in FIG. 1B, the recordable optical disk 11 has a light-transmissive substrate 12 having concentric or spiral guide grooves 12A, a mask layer 3 similar to the above, and optical recording. Recording layer 6 made of reproducible material
And the same reflective layer 4 and protective film layer 5 as described above are laminated in this order. The optical discs 1 and 11 shown in FIG. 1 are both reflection type optical discs, but they may be light transmission type optical discs that do not include the reflection layer 4 described above, and may further include a heat insulating layer, an enhancement layer, or a dielectric layer. A body layer or the like may be provided.

By the way, considering that the mask layer 3 having a uniform film thickness is formed on the uneven optical disk substrate as described above, the vacuum vapor deposition method excellent in film thickness control is advantageous as the forming method. Is. However, since the material of the mask layer 3 is an organic compound for both of the two components, the property is not deteriorated even if it is formed by a vacuum deposition method, and a sufficient disc super-resolution effect can be obtained even if it is a thin film. Must be selected. Furthermore, it is desirable that it is in a solid state at room temperature.

As a dye material which can be expected to have a sufficient disc super-resolution effect even if it is a thin film, Japanese Patent Application No. 6-261925.
There is a two-component pigment material as proposed in
The light transmittance of such a pigment material changes even without a plasticizer. It is necessary to select a suitable one as the mask layer 3 of the optical discs 1 and 11 from such two-component dye materials.

First, what is necessary for the mask layer 3 is that the light transmittance reversibly changes depending on whether the irradiation laser beam is turned on or off. Further, as described above, the speed at which the light transmittance changes / restores with respect to the irradiation of the laser light for optical recording / reproduction needs to be fast. Further, the dye material used as the mask layer 3 can be formed by the vacuum deposition method as described above.

Here, in general, a substance has a unique melting point which is a temperature at which a solid changes to a liquid, a boiling point which is a temperature at which a liquid changes to a gas, or a sublimation point which is a temperature at which a solid changes to a gas. In addition, when a compound is heated to a predetermined temperature, so-called decomposition occurs in which the compound molecule is separated into simpler molecules or atoms.

That is, the dye material usable in the above vacuum vapor deposition method is limited to those having a sublimation point or a boiling point.
It is necessary to evaporate in a molecular state or a cluster state (a state in which some compound molecules are assembled) at a temperature lower than the temperature at which the compound molecules decompose. Furthermore, it is desirable that the sublimation point and the boiling point are not close to the temperature at which the compound molecule decomposes.

Considering the above conditions, the electron-accepting color developer to be combined with the above-mentioned electron-donating color-forming compound for the mask layer 3 includes a bisphenol-type color developer having a high coloring density. A bisphenol-based developer is suitable, and specifically, an ether-based bisphenol,
Examples thereof include thioether bisphenol, bisphenol S, bisphenol S derivative, bisphenol A and bisphenol A derivative.

The general structural formulas (IV) to (VII) of these electron-accepting color developing agents are shown below. However, the structural formula (I
V) to (VII), R _{1 to} R ₅ and R _{1 ′ to} R _{5 ′}
Is a substituent selected from a hydrogen atom, a hydroxyl group, an aliphatic hydrocarbon group (preferably an aliphatic hydrocarbon group having 1 to 6 carbon atoms) or an alicyclic hydrocarbon group, and R _{1 to} R ₅ and At least one of R1 _'to R5 _' is a hydroxyl group. Also, 1
In those having two or more hydroxyl groups in the molecule, one of the hydroxyl groups is an -OR "group (R" in which a hydrogen atom is substituted with a linear or branched alkyl group having 1 to 6 carbon atoms.
May have 1 to 6 carbon atoms.

[0057]

[Chemical 25]

[0058]

[Chemical formula 26]

[0059]

[Chemical 27]

[0060]

[Chemical 28]

The bisphenol-based developer has both an electron-accepting color developing function and a color erasing function by light irradiation,
In addition, the color density is high. For this reason, it is possible to reduce the film thickness, and since it has very excellent transparency at the time of decoloring, it is extremely useful as a material for the mask layer 3.

Here, the film thickness of the mask layer 3 is determined by the absorbance specific to the dye material. This absorbance depends on the color density of the dye material. That is, it is necessary to increase the film thickness of the coloring material having a low coloring density, but it is possible to reduce the film thickness of a coloring material having a high coloring density. Therefore, the film thickness of the mask layer 3 using the dye material is appropriately determined depending on the combination of the dye materials used.

[0063]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described. A read-only optical disc 1 having the configuration shown in FIG.
30 (disc Nos. 1 to 30) were prepared by variously changing the electron-donating color-forming compound constituting the mask layer 3.
Specifically, the EFM of the shortest pit length of a compact disc (CD) is 0.34 μm and the track pitch is 0.79 μm.
The following structural formulas (1) to (3) are used as the mask layer 3 on the polycarbonate substrate 2 on which signals are recorded by a series of minute pits.
0) an electron-donating color-forming compound (made by Yamamoto Kasei) and bisphenol A as an electron-accepting developer are formed into a thin film by a vacuum deposition method (10-5 mbar, resistance heating),
Further, an A ₁ reflective layer 4 is formed thereon by a sputtering method to a thickness of 70 nm, and a photopolymer EX911 (manufactured by Dainippon Ink & Co., Inc.) is formed as a protective layer 5 on the reflective layer 4 for reproduction only. Type optical disk 1.

The mixing ratio (weight ratio) of the dye material of the mask layer 3 is as follows: electron donative color developing compound: electron accepting color developer = about 1: 0.5 to 1:50 (preferably 1: 1 to
1: 5), and the thickness of the mask layer 3 is 50 to 3000 nm.
(Preferably 400 to 2000 nm).

[0065]

[Chemical 29]

Formula (1): 3,3-bis (4-dimethylaminophenyl) -6-dimethylaminophthalide

[0067]

Embedded image

Formula (2): 3,3-bis (2-ethoxy-)
4-diethylaminophenyl) -4-azaphthalide

[0069]

[Chemical 31]

Formula (3): 3,3-bis (2-ethoxy-)
4-diethylaminophenyl) -7-azaphthalide

[0071]

Embedded image

Formula (4): 3- (2-ethoxy-4-diethylaminophenyl) -3- (4-diethylamino-2)
-Methoxyphenyl) -4-azaphthalide

[0073]

[Chemical 33]

Formula (5): 3,3-bis (4-diethylamino-2-n-butoxyphenyl) -4-azaphthalide

[0075]

Embedded image

Formula (6): 3,3-bis (4-diethylamino-2-methoxyphenyl) -4-azaphthalide

[0077]

Embedded image

Formula (7): 3- (2-ethoxy-4-diethylaminophenyl) -3- [2-ethoxy-4- (N
-Ethylanilino) phenyl] -4-azaphthalide

[0079]

Embedded image

Formula (8) ... 3- (4-Dimethylaminophenyl) -3- (1-ethyl-2-methyl-3-indolyl) phthalide

[0081]

Embedded image

Formula (9): 3- (4-diethylaminophenyl) -3- (1-ethyl-2-methyl-3-indolyl) phthalide

[0083]

[Chemical 38]

Formula (10): 3- (4-di-n-propylaminophenyl) -3- (1-ethyl-2-methyl-3)
-Indolyl) phthalide

[0085]

[Chemical Formula 39]

Formula (11): 3- (4-di-n-butylaminophenyl) -3- (1-ethyl-2-methyl-3-)
Indolyl) phthalide

[0087]

[Chemical 40]

Formula (12): 3- (4-diethylaminophenyl) -3- (1-n-butyl-2-methyl-3-indolyl) phthalide

[0089]

Embedded image

Formula (13): 3- (4-diethylamino-)
2-Methylphenyl) -3- (1-ethyl-2-methyl-3-indolyl) -4-azaphthalide

[0091]

Embedded image

Formula (14): 3- (4-diethylamino-)
2-Methylphenyl) -3- (1,2-dimethyl-3-
Indolyl) -4-azaphthalide

[0093]

[Chemical 43]

Formula (15): 3- [2-ethoxy-4-
(N-Ethylanilino) phenyl] -3- (1-ethyl-2-methyl-3-indolyl) -4-azaphthalide

[0095]

[Chemical 44]

Formula (16): 3- [1,1-bis (1-ethyl-2-methylindol-3-yl) ethylene-2
-Yl] -3- (4-dimethylaminophenyl) phthalide

[0097]

Embedded image

Formula (17): 3- [1,1-bis (1-ethyl-2-methylindol-3-yl) ethylene-2
-Yl] -3- (4-di-n-propylaminophenyl) phthalide

[0099]

Embedded image

Formula (18): 3- [1,1-bis (1-ethyl-2-methylindol-3-yl) ethylene-2
-Yl] -3- (4-pyrrolidinophenyl) phthalide

[0101]

[Chemical 47]

Formula (19): 3- [1,1-bis (1-ethyl-2-methylindol-3-yl) ethylene-2
-Yl] -3- (4-di-n-butylaminophenyl)
Phthalide

[0103]

Embedded image

Formula (20): 3- [1,1-bis (1-ethyl-2-methylindol-3-yl) ethylene-2
-Yl] -3- [4- (N-methyl-N-cyclohexylamino) phenyl] phthalide

[0105]

[Chemical 49]

Formula (21): 3- [1,1-bis (1-ethyl-2-methylindol-3-yl) ethylene-2
-Yl] -3- [4- (N-ethylanilino) phenyl] phthalide

[0107]

Embedded image

Formula (22): 3- [1,1-bis (1-ethyl-2-methylindol-3-yl) ethylene-2
-Yl] -3- (2-ethoxy-4-diethylaminophenyl) phthalide

[0109]

[Chemical 51]

Formula (23): 3- [1,1-bis (1-ethyl-2-methylindol-3-yl) ethylene-2
-Yl] -3- (4-diethylamino-2-methylphenyl) phthalide

[0111]

Embedded image

Formula (24): 10-diethylamino-2-
Ethylbenzo [1,4] thiazino [3,2-b] fluorane

[0113]

Embedded image

Formula (25): 2- (1,2,3,4-tetrahydroquinolin-1-yl) -6-diethylaminofluorane

[0115]

[Chemical 54]

Formula (26): 2-anilino-6-diethylaminofluorane

[0117]

[Chemical 55]

Formula (27): 2- (N-ethyl-N-phenylamino) -6-diethylaminofluorane

[0119]

[Chemical 56]

Formula (28): 2-dibenzylamino-6-
Diethylaminofluorane

[0121]

[Chemical 57]

Formula (29): 3,6,6'-tris (dimethylamino) spiro [fluorene-9,3'-phthalide]

[0123]

Embedded image

Formula (30): 2,6-bis (diethylamino) thiofluorane

The optical disk No. manufactured as described above was used. 1
˜30, emission center wavelengths 635, 680, 690
A reproduction experiment was carried out using a reproducing device having a laser of nm and a lens of NA = 0.6, and the ratio of 3T signal amplitude to 11T signal amplitude (I ₃ / I ₁₁ ,%) was measured and the results are displayed. Shown in 1. Further, the electron-donating color-forming compounds represented by the above formulas (1) to (30) develop color by mixing with bisphenol A or bisphenol S which is an electron-accepting color developer, but absorption during this color development Wavelength peak λ _max
(Nm) is also shown in the table.

[0126]

[Table 10]

As is clear from Table 10, the optical disk No. In the reproduced signal waveforms of 1 to 30, I ₃ / I ₁₁ (%) was 20 to 55% or more, and good reproduced signal waveforms could be obtained. Therefore, it was confirmed that the mask layer in which the electron-donating color-developing compound and the electron-accepting color developing agent were combined exhibited a good disc super-resolution effect in the wavelength range of 600 nm.

On the other hand, for comparison, an optical disk in which a mask layer was not formed on a polycarbonate substrate was prepared and evaluated in the same manner as above. I ₃ / I ₁₁ (%) was almost unmeasurable and was good. It was not possible to obtain a proper reproduced signal waveform.

[0129]

As is clear from the above description, according to the present invention, the mask layer composed of two components of the electron-donating color developing compound and the electron-accepting developer is 580 to 580.
By selecting the structures of the two compounds so as to have an absorption peak in the wavelength range of 720 nm, it becomes possible to provide an optical recording medium having a good super-resolution effect. In particular, a dye material containing at least one of the electron-donating color-forming compounds represented by the general formulas (I) to (IX), which has a high color density in the wavelength range of 600 nm, and an electron-accepting developer is used. By forming the mask layer, a disc super-resolution effect is exhibited, and a signal recorded at high density can be stably reproduced. In addition, the mask layer can be formed by a vacuum vapor deposition method with excellent film thickness controllability, and since it becomes a mask layer with large light absorption, there is an advantage that the film thickness can be reduced.

[Brief description of drawings]

FIG. 1 is a diagram showing a structure of an embodiment of an optical disc of the present invention.

FIG. 2 is a diagram showing response characteristics of a mask layer in FIG.

FIG. 3 is a diagram showing light transmittance characteristics of the mask layer in FIG.

FIG. 4 is a diagram showing a mask effect of the mask layer in FIG.

5 is a diagram comparing the light intensity distributions of the irradiation spot diameter and the effective spot diameter of the mask layer in FIG.

[Explanation of symbols]

 1, 11 Optical disc (optical recording medium) 2, 12 Light transmissive substrate 2A Pit 3 Mask layer 4 Reflective layer 5 Protective film layer 6 Recording layer 12A Guide groove

Claims (4)

[Claims] 1. A mask in which light transmittance is reversibly changed by temperature change due to light irradiation on a light-transmissive substrate on which light-readable minute pit rows or concentric or spiral guide grooves are formed. In the optical recording medium having a layer, the effective spot diameter of the reproducing laser beam is reduced by utilizing the change in the light transmittance of the mask layer, wherein the mask layer comprises an electron-donating coloring compound and an electron-accepting compound. The main component is a thermochromic material whose light transmittance reversibly changes with only two components of the sex developer, and the absorption peak is 580 to 72.
An optical recording medium characterized in that it has a wavelength range of 0 nm. 2. The electron donating color-forming compound is any one of compounds represented by the following general formulas (I) to (IX).
The optical recording medium according to claim 1, which is a seed or a mixture thereof. Embedded image In the formula, R ₁ , R ₂ , R ₃ and R ₄ are each independently a hydrogen atom,
It represents an unsubstituted or substituted alkyl group or an unsubstituted or substituted phenyl group, and R ₁ and R ₂ , and R ₃ and R ₄ may be linked to each other to form a heterocycle together with the bonded nitrogen atom. X ₁ and X ₂ are a hydrogen atom, an unsubstituted or substituted alkyl group, an unsubstituted or substituted phenyl group, an unsubstituted or substituted alkoxy group, an unsubstituted or substituted phenyloxy group, an unsubstituted or substituted alkylthio group, an unsubstituted or substituted phenylthio group Group, dialkylamino group, and halogen atom. Ring A ₁ represents a substituent represented by the following structural formula (I): In the formula, Z ₁ represents a hydrogen atom, an unsubstituted or substituted alkyl group, an unsubstituted or substituted alkoxy group, a dialkylamino group, or a halogen atom, and n ₁ represents an integer of ₁ to 4. Embedded image In the formula, R ₅ , R ₆ , R ₇ and R ₈ are each independently a hydrogen atom,
It represents an unsubstituted or substituted alkyl group or an unsubstituted or substituted phenyl group, and R ₅ and R ₆ may form a heterocycle together with the nitrogen atom which is connected to and bonded to each other. X ₃ ,
X ₄ and X ₅ are hydrogen atom, unsubstituted or substituted alkyl group, unsubstituted or substituted alkoxy group, unsubstituted or substituted phenyloxy group, unsubstituted or substituted alkylthio group, unsubstituted or substituted phenylthio group, dialkylamino group, halogen Indicates an atom. Ring A ₂ represents a substituent represented by the following structural formula (I): In the formula, Z ₂ represents a hydrogen atom, an unsubstituted or substituted alkyl group, an unsubstituted or substituted alkoxy group, a dialkylamino group, or a halogen atom, and n ₂ represents an integer of 1 to 4. Embedded image In the formula, R ₉ , R ₁₀ , R ₁₁ , R ₁₂ , R ₁₃ and R ₁₄ represent a hydrogen atom, an unsubstituted or substituted alkyl group, an unsubstituted or substituted alkoxyalkyl group, an unsubstituted or substituted phenyl group, and R ₉ and R ₁₀ may form a heterocycle together with the nitrogen atom which is connected to each other and bonded. X ₆ ,
X ₇ , X ₈ , X ₉ and X ₁₀ are hydrogen atoms, unsubstituted or substituted alkyl groups, unsubstituted or substituted alkoxy groups, unsubstituted or substituted phenyloxy groups, unsubstituted or substituted alkylthio groups, unsubstituted or substituted phenylthio groups , A dialkylamino group and a halogen atom. Ring A ₃
Represents a substituent represented by the following structural formula (III): In the formula, Z ₃ represents a hydrogen atom, an unsubstituted or substituted alkyl group, an unsubstituted or substituted alkoxy group, a dialkylamino group, or a halogen atom, and n ₃ represents an integer of 1 to 4. However, 3- [1,1-bis (1-ethyl-2-
Methylindol-3-yl) -ethylene-2-yl]
Excludes -3- (4-diethylaminophenyl) phthalide. [Chemical 7] Wherein, R _15, R ₁₆ is a hydrogen atom, an unsubstituted or substituted alkyl group, unsubstituted or substituted alkoxyalkyl group, an unsubstituted or substituted phenyl group, also, R1 ₅ and R ₁₆
May form a heterocycle with the nitrogen atoms which are linked to each other and bonded. R ₁₇ represents a divalent hydrocarbon group having 2 to 6 carbon atoms. Embedded image Wherein, R _18, R ₁₉ represents a hydrogen atom, an unsubstituted or substituted alkyl group, unsubstituted or substituted alkoxyalkyl group, an unsubstituted or substituted phenyl group, also, R1 ₈ and R ₁₉
May form a heterocycle with the nitrogen atoms which are linked to each other and bonded. R ₂₀ represents a hydrogen atom, an unsubstituted or substituted alkyl group, an unsubstituted or substituted benzyl group. [Chemical 9] Wherein, R _21, R ₂₂ is a hydrogen atom, an unsubstituted or substituted alkyl group, unsubstituted or substituted alkoxyalkyl group, an unsubstituted or substituted phenyl group, also, R2 ₁ and R ₂₂
May form a heterocycle with the nitrogen atoms which are linked to each other and bonded. R ₂₃ represents a hydrogen atom or an alkyl group. [Chemical 10] Wherein, R _24, R ₂₅ is a hydrogen atom, an unsubstituted or substituted alkyl group, unsubstituted or substituted alkoxyalkyl group, an unsubstituted or substituted phenyl group, also, R2 ₄ and R ₂₅
May form a heterocycle with the nitrogen atoms which are linked to each other and bonded. R ₂₆ represents a hydrogen atom or an alkyl group. [Chemical 11] In the formula, R ₂₇ , R ₂₈ , R ₂₉ , R ₃₀ , R ₃₁ and R ₃₂ represent a hydrogen atom, an unsubstituted or substituted alkyl group, an unsubstituted or substituted alkoxyalkyl group, an unsubstituted or substituted phenyl group, and R ₂₇ and R ₂₈ , R ₂₉ and R ₃₀ , R ₃₁ and R
₃₂ may form a heterocycle together with the nitrogen atom which is connected to each other and bonded. [Chemical 12] In the formula, R ₃₃ , R ₃₄ , R ₃₅ and R ₃₆ represent a hydrogen atom, an unsubstituted or substituted alkyl group, an unsubstituted or substituted alkoxyalkyl group, an unsubstituted or substituted phenyl group,
In addition, R ₃₃ and R ₃₄ , and R ₃₅ and R ₃₆ may form a heterocycle together with the nitrogen atom which is connected to and bonded to each other. 3. The optical recording medium according to claim 1, wherein the electron-accepting developer is a bisphenol-based developer. 4. The bisphenol-based developer is an ether-based bisphenol, a thioether-based bisphenol,
The optical recording medium according to claim 3, which is at least one of a bisphenol S compound and a bisphenol A compound.