JPH11162006A - Optical recording medium and optical recording / reproducing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical recording medium and an optical recording / reproducing method which have high reflectivity and excellent signal output characteristics with respect to light of a predetermined wavelength and are capable of recording / reproducing without destruction of reading. With the goal. SOLUTION: The present invention has a configuration in which at least a recording layer 2, an intermediate layer 3, and a reflective layer 4 containing a dye that absorbs recording light are sequentially formed on a transparent substrate 1. The reflectance R, the transmittance T, and the absorptance A when light of the recording wavelength and the reproduction wavelength are incident from the recording layer side of the laminated film composed of the layers are (R + T + A = 1), R ≧ 0.5 or T ≧ The reflectance R ′, the transmittance T ′, and the absorption when light having a reproduction wavelength less than the recording wavelength is incident from the recording layer side of the laminated film including the recording layer and the intermediate layer having such a configuration, or an optical recording medium satisfying 0.5. The rate A 'is (R' + T '
+ A ′ = 1), an optical recording medium satisfying R ′ ≧ 0.4 or T ′ ≧ 0.4, and an optical recording / reproducing method using the same.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an optical recording medium and an optical recording / reproducing method, and more particularly to an optical recording medium using an optical recording medium having an intermediate layer.

[0002]

2. Description of the Related Art As an optical recording medium for reproducing information by a laser beam, a read-only optical disk (hereinafter, referred to as a CD or CD-ROM) is widely used for music reproduction and information terminals.

In this optical recording medium, information is recorded by providing an uneven pit array on one side of a transparent substrate having a thickness of 1.2 mm, and a reflective film of aluminum, gold or the like is formed thereon by sputtering or vapor deposition. It is common to have a configuration in which a protective film is coated thereon.

This optical recording medium has a wavelength of 780n.
When the semiconductor laser light of m is incident through the transparent substrate and is reflected by the reflection film, the change in the reflectance corresponding to the unevenness of the pre-recorded information pit is read, and the pre-recorded information is reproduced. Is what you do.

However, CDs and CD-ROMs are read-only media and do not have an editing function.

Therefore, as recordable optical recording media, write-once optical disks (hereinafter, referred to as CD-R), rewritable optical disks (hereinafter, referred to as phase change type), etc., which can be recorded only once, have been developed and put into practical use. Such recordable optical discs are provided with a playback function of CD, CD,
-Compatible with ROM.

[0007] Due to this reproduction compatibility, an information terminal device equipped with a CD-ROM reproduction device can reliably reproduce recorded CD-R information.

By providing a CD-ROM device with a CD-R recording function, it is possible to provide an information recording device having the same capacity as a CD-ROM and having a capacity of 650 Mbytes per sheet.

For this reason, in recent years, in particular, CD-Rs have come into widespread use as information recording media.

Further, when editing the information content of the CD-ROM, it is necessary to test-produce the CD-ROM.

[0011] Even in such an authoring business as an editing business, a CD-R compatible with a CD-ROM playback function is used.
It is an indispensable key device in the trial operation of CD-ROM.

Here, in the case of CD-Rs, those in which chalcogenite compounds such as Te, rare earth metal compounds, porphyrin compounds, cyanine compounds and naphthalocyanine compounds are applied to the recording layer have been put to practical use. I have.

In recent years, especially for CD-Rs, those using an organic compound such as a dye for the recording layer have become mainstream from the viewpoints of price, pollution-free properties, and complete compatibility of reproduction characteristics with the aforementioned CD-ROM. In this configuration, a laser beam having a relatively large output is made incident in correspondence with an information signal, and the incident laser light is absorbed by an organic compound of the recording layer and converted into heat, thereby causing a chemical reaction of the recording layer. This causes a change or a change in the geometrical shape, and causes additional information to be added.

Further, the information recorded in this manner is irradiated with a relatively low-power laser beam of a fixed value or less to recognize a change in reflectivity, specifically, a change in the amount of reflected light. Information will be reproduced.

Examples of the organic compound used in such a recording layer include, for example, Japanese Patent Application Laid-Open No. 1-145188 for a porphyrin compound, and particularly Japanese Patent Application Laid-Open Nos. 3-1382 and 3-1382 for a tetraazaporphyrin compound. JP-A-13384 and JP-A-7-276804, and the like. Further, phthalocyanine compounds are disclosed in JP-A-2-276676 and the like, and naphthalocyanine compounds are disclosed in JP-B-4-20945. ing.

On the other hand, the development of next-generation high-density optical recording media is actively progressing. A major feature of this next-generation high-density optical recording medium is that the wavelength of laser light is 620 to 690 nm.
The recording density is improved by shortening the wavelength and shortening the interval and length of the track pitch, and 3 to 10 G, which is 5 to 10 times larger than the recording capacity of the current CD-ROM of 650 Mbytes.
It enables handling of digital data of bytes.

However, according to the current standard, this high-density optical recording medium is also used for reproduction only and has no editing function.

For this reason, a recordable high-density write-once optical disc having an editing function has been energetically studied. In particular, it is desired to use an organic material for the recording layer as in the case of the CD-R. I have.

As a specific disclosure, a recording medium in which the light absorption characteristics of a cyanine compound is shifted to a short wavelength is disclosed in JP-A-6-199045, and an indoline imine dye is added to a recording layer. The applied recording medium is disclosed in JP-A-5-305771, JP-A-4-252.
272, etc.

While such a high-density optical recording medium has been developed, a CD-R (hereinafter, referred to as a CD-R) which can be reproduced by a high-density recording-compatible player has been used because of its compatibility with conventional systems which have already been widely used. , CD-R2).

[0021] Conventional CDs and CD-ROMs have a small wavelength dependence of reflectivity, and can be reproduced by players capable of high-density recording.

[0022]

However, the conventional CD-R having a dye in the recording layer has a large wavelength dependence of the reflectance due to the large wavelength dependence of the optical constant of the dye. It is difficult to achieve both recording and reproduction with a CD, CD-ROM player and reproduction with a high-density recording compatible player.

In consideration of this point, for example, Japanese Patent Application Laid-Open No. Hei 8-2
In JP-A-63872, JP-A-8-263873 and JP-A-8-31010, the refractive index, extinction coefficient and film thickness of the light absorbing layer are set in appropriate ranges according to different wavelengths. The reflectance with a near-infrared laser having a wavelength of 770 to 830 nm is 65% or more, and a wavelength of 620
An optical recording medium CD-R2 satisfying a reflectance of 15% or more with a red laser having a wavelength of ｎｍ690 nm has been proposed, but it is not sufficient in terms of recording / reproducing characteristics.

According to the present invention, at least a transparent substrate is provided.
Using an optical recording medium in which a recording layer containing a dye that absorbs recording light, an intermediate layer, and a reflective layer are sequentially formed, good recording and reproduction for light of a predetermined wavelength, that is, high reflectance and excellent signal An object of the present invention is to provide an optical recording medium and an optical recording / reproducing method which have output characteristics and are capable of recording / reproducing without destruction of reading / reading by repeated reproduction.

[0025]

Means for Solving the Problems In order to solve the above problems,
The present invention has a configuration in which at least a recording layer containing a dye that absorbs recording light, an intermediate layer, and a reflective layer are sequentially formed on a transparent substrate, at a recording wavelength of recording light and a reproduction wavelength of reproduction light. When light is incident from the recording layer side of the laminated film including the recording layer and the intermediate layer, the reflectance is R, the transmittance is T, and the absorptance is A (R + T + A = 1). An optical recording medium that satisfies ≧ 0.5, and a reflectance when light is incident from the recording layer side of the laminated film including the recording layer and the intermediate layer at the reproduction wavelength of the reproduction light shorter than the recording wavelength of the recording light in such a configuration. Is R ′, transmittance is T ′, and absorptance is A ′ (R ′ + T ′ + A ′ = 1), an optical recording medium satisfying R ′ ≧ 0.4 or T ′ ≧ 0.4, and This is an optical recording / reproducing method using this.

Here, the reflectance, transmittance, and the like when light is incident from the recording layer side of the laminated film composed of the recording layer and the intermediate layer.
The absorptance is obtained by calculation from the refractive index and the extinction coefficient, which are determined from the film thickness dependence of the reflectance and transmittance of the recording layer and the intermediate layer alone formed separately on the quartz substrate. is there.

With such a configuration, on a transparent substrate,
At least, a recording layer containing a dye that absorbs recording light,
Using an optical recording medium in which an intermediate layer and a reflective layer are sequentially formed,
Provided are an optical recording medium and an optical recording / reproducing method capable of performing good recording / reproducing with respect to light having a predetermined wavelength.

[0028]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention according to claim 1, wherein a transparent substrate, a recording layer provided on the substrate and containing a dye absorbing recording light, and an intermediate layer provided on the recording layer And a reflective layer provided on the intermediate layer, and when light is incident from the recording layer side of the laminated film including the recording layer and the intermediate layer at the recording wavelength of the recording light and the reproduction wavelength of the reproduction light. The optical recording medium satisfies R ≧ 0.5, where R is the reflectance, T is the transmittance, and A is the absorptance (R + T + A = 1).

With such a configuration, an intermediate layer is provided, and the effect of the intermediate layer and the reflective layer of an optical recording medium of the type utilizing the interference effect due to multiple reflection is maximized, so that good recording and reproduction can be performed.

If the above conditions are not satisfied, even if there is an intermediate layer, the effect is hardly seen, and the reflectivity is lowered,
Phenomena such as a disturbance of the reproduction signal waveform occur.

According to a second aspect of the present invention, there is provided a transparent substrate, a recording layer provided on the substrate and containing a dye that absorbs recording light, and an intermediate layer provided on the recording layer. A reflection layer provided on the intermediate layer, and reflection when light is incident from the recording layer side of the laminated film including the recording layer and the intermediate layer at the recording wavelength of the recording light and the reproduction wavelength of the reproduction light. The optical recording medium satisfies T ≧ 0.5, where R is the transmittance, T is the transmittance, and A is the absorptance (R + T + A = 1).

According to such a structure, an intermediate layer is provided, and the effect of the intermediate layer and the reflective layer of an optical recording medium of the type utilizing the interference effect by multiple reflection is maximized, so that good recording and reproduction can be performed. .

If the above conditions are not satisfied, even if there is an intermediate layer, the effect is hardly seen, and the reflectivity decreases,
Phenomena such as a disturbance of the reproduction signal waveform occur.

Here, as described in claim 3, the absorption rate A
Is preferably 30% or less.

If the absorption ratio A is 30% or more, the absorption is too large, and the interference effect of multiple reflection is reduced.

And, as described in claim 4, further,
At the reproduction wavelength of the reproduction light shorter than the recording wavelength of the recording light, when light is incident from the recording layer side of the laminated layer including the recording layer and the intermediate layer, the reflectance is R ′, the transmittance is T ′, and the absorption is A. ′ (R ′ + T ′ + A ′ = 1), R ′ ≧ 0.
It is also preferable to satisfy Condition 4.

With such a configuration, an intermediate layer is provided to maximize the effects of the intermediate layer and the reflective layer of an optical recording medium of the type utilizing the interference effect due to multiple reflection, and good recording / reproduction under such conditions. It becomes possible.

If the above conditions are not satisfied, the effect of the intermediate layer is hardly observed, and phenomena such as a decrease in reflectivity and a disturbance in the reproduced signal waveform will occur.

And, as described in claim 5, further,
At the reproduction wavelength of the reproduction light shorter than the recording wavelength of the recording light, when light is incident from the recording layer side of the laminated layer including the recording layer and the intermediate layer, the reflectance is R ′, the transmittance is T ′, and the absorption is A. ′ (R ′ + T ′ + A ′ = 1), T ′ ≧ 0.
It is also preferable to satisfy Condition 4.

With such a configuration, an intermediate layer is provided to maximize the effects of the intermediate layer and the reflective layer of an optical recording medium of the type utilizing the interference effect due to multiple reflections. Becomes possible.

If the above conditions are not satisfied, the effect of the intermediate layer is hardly observed, and phenomena such as a decrease in reflectivity and a disturbance in the waveform of a reproduced signal occur.

Alternatively, as described in claim 6, a transparent substrate, a recording layer provided on the substrate and containing a dye that absorbs recording light, and an intermediate layer provided on the recording layer,
A reflection layer provided on the intermediate layer, and reflection when light is incident from the recording layer side of the recording layer and the intermediate layer at the reproduction wavelength of the reproduction light shorter than the recording wavelength of the recording light. The optical recording medium satisfies R ′ ≧ 0.4, where R ′ is R ′, T ′ is transmittance, and A ′ is absorptivity (R ′ + T ′ + A ′ = 1).

With such an arrangement, an intermediate layer is provided to maximize the effects of the intermediate layer and the reflective layer of an optical recording medium of the type utilizing the interference effect due to multiple reflection, so that good recording and reproduction can be performed under such conditions. It becomes possible.

If the above conditions are not satisfied, the effect of the intermediate layer is hardly observed, and phenomena such as a decrease in the reflectivity and a disorder of the reproduced signal waveform will occur.

Alternatively, as described in claim 7, a transparent substrate, a recording layer provided on the substrate and containing a dye absorbing recording light, and an intermediate layer provided on the recording layer,
A reflective layer provided on the intermediate layer, wherein the reflectance of the laminated film including the recording layer and the intermediate layer at the reproduction wavelength of the reproduction light shorter than the recording wavelength of the recording light is R ′, and the transmittance is T ′. ,
Assuming that the absorption rate is A '(R' + T '+ A' = 1),
The optical recording medium satisfies T ′ ≧ 0.4.

With such a configuration, an intermediate layer is provided to maximize the effects of the intermediate layer and the reflective layer of an optical recording medium of the type utilizing the interference effect by multiple reflection, and good recording / reproduction under such conditions. It becomes possible.

If the above conditions are not satisfied, the effect of the intermediate layer is hardly observed, and phenomena such as a decrease in reflectivity and a disturbance in the waveform of a reproduced signal occur.

Here, as described in claim 8, it is preferable that the absorption rate A 'is 50% or less.

If the absorption ratio A is 50% or more, the absorption is too large, and the interference effect of multiple reflection is reduced.

According to a ninth aspect of the present invention, the reflective layer comprises:
A metal layer is preferable because of its good reflection function.

Further, as in the tenth aspect, a structure having a protective layer outside the reflective layer may be adopted.

On the other hand, the present invention according to a method, as described in claim 11, uses the optical recording medium according to any one of claims 1 to 6 to irradiate a laser beam having a wavelength range of 770 to 830 nm. An optical recording method for recording information, wherein recording is reliably performed by using a laser beam within such a wavelength range.

According to a twelfth aspect of the present invention, there is provided an optical recording method for recording information by irradiating a laser beam having a wavelength range of 620 to 690 nm using the optical recording medium according to any one of the first to sixth aspects. In this case, the recording is reliably performed by using the laser light within the wavelength range.

Alternatively, the recorded information is reproduced by irradiating the optical recording medium according to any one of claims 1 to 6 with a laser beam having a wavelength range of 770 to 830 nm. In this method, the reproduction is reliably performed by using a laser beam within the above wavelength range.

Alternatively, the recorded information is reproduced by irradiating the optical recording medium according to any one of claims 1 to 6 with a laser beam having a wavelength range of 620 to 690 nm. In this method, the reproduction is reliably performed by using a laser beam within the above wavelength range.

According to a fifteenth aspect, information is recorded by irradiating a laser beam having a wavelength range of 770 to 830 nm or 620 to 690 nm using the optical recording medium according to any one of the third to sixth aspects. And a wavelength range of 770 to 83
0 nm or 620-690 nm laser light,
An optical recording / reproducing method for reproducing recorded information by irradiating a shorter wavelength than the wavelength of the recording light, wherein recording and reproduction are surely performed by using a laser beam within the wavelength range.

That is, the inventor of the present invention has proposed an optical recording medium in which at least a recording layer containing a dye absorbing recording light, an intermediate layer, and a reflective layer are sequentially formed on a transparent substrate. In order to achieve good recording and reproduction with respect to light,
As a result of intensive studies, it is very important to control the reflectivity between the substrate and the recording layer, between the recording layer and the intermediate layer, and between the intermediate layer and the reflective layer. 1) effectively utilizing the reflectance of the recording layer by suppressing the transmittance of the recording layer alone film; and (2) effectively utilizing the reflectance of the recording layer other than the recording layer by suppressing the reflectance of the recording layer sole film. It has been found that choosing is an important point.

More specifically, the inventors have found that the reflectance R and the transmittance T of the laminated recording layer and intermediate layer are very important parameters. At this time, if the absorptance of the single recording layer is A, then R + T + A = 1.

That is, by setting R and T in a specific range for a recording light having a specific wavelength and a reproducing light having the same wavelength, an optical recording medium capable of excellent recording and reproduction can be obtained. Further, by setting these R and T to specific ranges for recording light of a specific wavelength and reproducing light of a shorter wavelength, an optical recording medium capable of excellent recording and reproduction is found. This has led to the present invention.

In the above, the material of the substrate is basically required to be transparent at the wavelength of the recording and reproducing light, and more preferably a material having a small thermal conductivity. Specifically, for example, polycarbonate resin, acrylic resin, epoxy resin, glass, amorphous polyolefin and the like can be used.

The substrate may be in the form of a plate, a film or a card, but preferably has a disk shape defined by an appropriate thickness and diameter with respect to the focal point of the optical system of the laser light used as the light source. It is more preferable that a guide groove is provided on one side of the substrate, and a substrate that can be formed by cutting or injection molding is preferable.

The recording layer may be formed directly on the transparent substrate or through another layer, and has an appropriate absorption and heat conversion efficiency with respect to the recording light and a relatively strong recording light. By giving energy, physical and chemical decomposition, alteration,
There is no particular limitation as long as it involves deformation.

Specifically, dyes are preferred, but phthalocyanine dyes, naphthalocyanine dyes, porphyrin dyes, detraazaporphyrin dyes, cyanine dyes, azo dyes and the like can be mentioned. Further, these may include a metal.

The recording layer can be formed by using a spin coating method, a vacuum evaporation method, a sputtering method or the like.

In the spin coating method, a recording layer is formed by dissolving an organic dye in a solvent and dropping the dye solution while rotating a transparent substrate.

This dye solution is preferably adjusted to a dye concentration of 0.5 to 5% by weight, and a solvent for preparing the dye solution can be used as long as it dissolves the dye and is harmless to the transparent substrate.

Examples of the solvent include methyl alcohol, ethanol, propanol, butanol, tetrafluoro alcohol, acetone methyl ethyl ketone, diethyl ether, dipropyl ether, dibutyl ether, tetrahydrofuran, dioxane, methyl acetate, ethyl acetate,
Propyl acetate, butyl acetate, benzene, toluene, xylene, naphthalene, hexane, cyclohexane, methyl chloride, dichloromethane, chloroform, carbon tetrachloride,
Dichloroethane, trichloroethane, 2-methoxyethanol, 2-ethoxyethanol, 2-isopropoxyethanol, acetonitrile, triethylamine, dipropylamine, dimethylformamide, etc .; dye solubility, workability, influence on substrates, economic efficiency Is determined in consideration of

Of course, when a dye solution is prepared by dissolving a dye in an organic solvent, a light stabilizer and an antioxidant may be contained. As the light stabilizer, a metal complex or diimonium salt which is a singlet oxygen quencher, a hindered amine compound, a benzotriazole compound, a benzophenone compound as an ultraviolet absorber, a phenolic antioxidant as a primary antioxidant as an antioxidant, Amine-based antioxidants and secondary antioxidants include organic sulfur-based secondary antioxidants and phosphorus-based secondary antioxidants. These light stabilizers and antioxidants may be used alone or in combination. The amount of the dye added was 100
The amount of the additive is preferably about 0.1 to 200 parts per part.

Further, resins may be added to the dye solution as a binder, and these resins may be nitrocellulose, cellulose phosphate, cellulose sulfate, cellulose acetate, cellulose propionate, cellulose butyrate, cellulose myristate, palmitate. Cellulose, cellulose acetate and propionate, cellulose esters such as cellulose acetate and butyrate, cellulose ethers such as methyl cellulose, ethyl cellulose, propyl cellulose, butyl cellulose, polystyrene, polyvinyl chloride, polyvinyl acetate, polyvinyl butyral, polyvinyl acetal,
Vinyl resins such as polyvinyl alcohol and polyvinyl pyrrolidone, styrene-butadiene copolymer, styrene-acrylonitrile copolymer, styrene-butadiene-acrylonitrile copolymer, copolymer resins such as vinyl chloride-vinyl acetate copolymer, polymethyl methacrylate, polymethyl acrylate, poly Acrylic acid,
Acrylic resins such as polymethacrylic acid, polyacrylamide and polyacrylonitrile, polyesters such as polyethylene terephthalate, poly (4,4-isopropylidenediphenylene-co-1,4-cyclohexylene dimethylene carbonate), poly (ethylene Dioxy-
3,3-phenylene thiocarbonate), poly (4,4
-Isopropylidene diphenylene carbonate-co-terephthalate), poly (4,4-isopropylidene diphenylene carbonate), poly (4,4-sec-butylidene diphenylene carbonate), poly (4,4-isopropylidene diphenylene carbonate) −Block−
Polyacrylate resins such as oxyethylene), polyamides, epoxy resins, phenolic resins, and polyolefins such as polyethylene, polypropylene, and chlorinated polyethylene can be used. These resins can be added in the range of 1 to 1000 parts per 100 parts by weight of the dye.

In order to form a recording layer by the spin coating method, a desired film thickness is adjusted by the dye concentration, the number of rotations, and the rotation time.

When the recording layer is formed by a method such as vapor deposition, it is desirable that the recording layer is deposited at a degree of vacuum of 10 ⁻² Pa or less.

A recording layer can also be formed by simultaneously vapor-depositing a light stabilizer and an antioxidant that can be vapor-deposited. In this case, the light stabilizer, antioxidant and the like are selected from the compounds described above. In the vapor deposition, the recording layer dye and the additive may be mixed in a predetermined amount and may be deposited by one heat source, or the additive and the dye may be deposited by separate heat sources.

The intermediate layer preferably has a smaller extinction coefficient than the recording layer, but the extinction coefficient does not necessarily have to be zero.

More specifically, organic materials such as phenolic resins, vinyl alcohol resins, butyral resins, polyimide resins, acrylic resins, silicone resins and copolymer resins thereof, silicon, titanium, zirconium, etc. And inorganic materials such as oxides, nitrides, MgF ₂ , and ZnS.

For the reflection layer, a material having a high reflectance with respect to the wavelength of the light source used is used. The material to be used is preferably a metal, and is preferably aluminum, silver, gold, iron, nickel, cobalt, tin, zinc, copper or the like, and these can be used alone or as an alloy. This reflective layer is formed to a thickness of about 10 to 200 nm by a sputtering method or the like.

The protective layer is provided for protecting the recording layer or the reflective layer from scratches and stains and for preservation stability. As the inorganic material, SiO or SiO ₂ can be used. Organic materials include polymethyl acrylate, polycarbonate,
Epoxy resin, polystyrene, polyester resin, vinyl resin, cellulose, aliphatic hydrocarbon resin, aromatic hydrocarbon resin, natural rubber, wax, alkyd resin, drying oil, rosin, etc. Can be used. This protective layer may optionally contain a flame retardant,
Stabilizers, antistatic agents and the like can be added. Further, the resin substrates may be bonded together with an adhesive.

Hereinafter, the optical recording medium of the present invention and an optical recording / reproducing method using the same will be described in detail with reference to each embodiment.

(Embodiment 1) FIG. 1 is an enlarged view of a cross section of an optical recording medium of the present embodiment.

In FIG. 1, 1 is a transparent substrate, 2 is a recording layer formed on the transparent substrate 1, 3 is an intermediate layer formed on the recording layer 2, 4 is a reflective layer formed on the intermediate layer 3 , And 5
Is a protective layer formed on the reflective layer 4.

The substrate 1 is a transparent disk-shaped transparent substrate made of polycarbonate, having a thickness of 1.2 mm and a pitch of 1.6.
What was injection-molded into a shape of μm, width 0.5 μm, and depth 50 nm was used.

Next, as a recording layer 2 on the substrate 1,
Typically, tin chloride phthalocyanine represented by the following chemical formula (Formula 1) is used to form a film so as to have an average film thickness of 50 nm by a vacuum deposition method, and polycarbonate is formed thereon as an intermediate layer 3 by a vacuum deposition method. Film thickness 100, 120, 14
Films were formed at 0, 160 and 180 nm.

[0082]

Embedded image

Here, the optical constant of the recording layer 2 is such that the refractive index n3 = 4.24 and the extinction coefficient k at a wavelength of 780 nm.
3 = 0.79 and the refractive index n at a wavelength of 760 nm
3 = 4.10, extinction coefficient k3 = 2.53, and wavelength 7
At 50 nm, refractive index n3 = 3.77, extinction coefficient k3
= 3.09 and the refractive index n3 at a wavelength of 635 nm
= 0.99, extinction coefficient k3 = 0.90, and wavelength 60
At 0 nm, the refractive index n3 = 1.04 and the extinction coefficient k3 =
0.39, and the refractive index n3 =
0.98 and the extinction coefficient k3 = 0.07.

The optical constant of the intermediate layer 3 is such that the refractive index n4 = 1.59 and the extinction coefficient k4 = 0 at all the wavelengths used here.

Therefore, the reflectance R, the transmittance T, and the absorptance A of the laminated film of the recording layer and the intermediate layer are R = 0.53 and T = 0.03 at a wavelength of 780 nm when the thickness of the intermediate layer is 100 nm.
26, A = 0.21 and R at a wavelength of 760 nm
= 0.55, T = 0.07, A = 0.38, and at a wavelength of 750 nm, R = 0.57, T = 0.05, A =
0.38, and R = 0.2 at a wavelength of 635 nm.
9, T = 0.46, A = 0.25, wavelength 600n
m = 0, R = 0.21, T = 0.62, A = 0.17
Where R = 0.18 and T =
0.77, A = 0.05.

The reflectance R, transmittance T and absorptance A of the laminated film of the recording layer and the intermediate layer are R = 0.50 and T = 0.2 at a wavelength of 780 nm when the intermediate layer thickness is 120 nm.
7, A = 0.23, and R =
0.54, T = 0.07, A = 0.39, wavelength 7
At 50 nm, R = 0.57, T = 0.04, A =
0.39, and R = 0.2 at a wavelength of 635 nm.
6, T = 0.43, A = 0.31, wavelength 600n
m = 0, R = 0.17, T = 0.61, A = 0.22
Where R = 0.14 and T =
0.80, A = 0.06.

The reflectance R, transmittance T, and absorptance A of the laminated film of the recording layer and the intermediate layer are R = 0.51 and T = 0.2 at a wavelength of 780 nm when the intermediate layer thickness is 140 nm.
5, A = 0.24, and R =
0.53, T = 0.06, A = 0.41, wavelength 7
At 50 nm R = 0.56, T = 0.04, A =
0.40, and R = 0.2 at a wavelength of 635 nm.
2, T = 0.41, A = 0.37, wavelength 600n
m = 0, R = 0.11, T = 0.62, A = 0.27
Where R = 0.01 and T =
0.91 and A = 0.08.

The reflectance R, transmittance T, and absorptance A of the laminated film of the recording layer and the intermediate layer are R = 0.54 and T = 0.0 at a wavelength of 780 nm when the thickness of the intermediate layer is 160 nm.
5, A = 0.41, and R =
0.54, T = 0.05, A = 0.41, wavelength 7
At 50 nm, R = 0.16, T = 0.03, A =
0.41 and R = 0.1 at a wavelength of 635 nm.
6, T = 0.41, A = 0.43, wavelength 600n
In m, R = 0.05, T = 0.64, A = 0.31
Where R = 0.01 and T =
0.91 and A = 0.08.

The reflectance R, transmittance T and absorptance A of the laminated film of the recording layer and the intermediate layer are R = 0.57 and T = 0.1 at a wavelength of 780 nm when the thickness of the intermediate layer is 180 nm.
8, A = 0.25, and at a wavelength of 760 nm, R =
0.54, T = 0.05, A = 0.41, wavelength 7
At 50 nm, R = 0.58, T = 0.02, A =
0.40, and R = 0.1 at a wavelength of 635 nm.
2, T = 0.43, A = 0.31, wavelength 600n
m = 0, R = 0.03, T = 0.67, A = 0.30
Where R = 0.01 and T =
0.92 and A = 0.07.

Next, a gold thin film having a thickness of 100 nm was formed as a reflective layer 4 on the intermediate layer 3 by sputtering.

Further, an ultraviolet-curable resin was applied on the reflective layer 4 by a spin coating method, and was cured by irradiating ultraviolet rays. The cured resin was used as a protective layer 5 to produce 10 optical recording media.
In addition, the following measured value was made into the average value of ten each.

FIG. 2 shows the results obtained by measuring the reflectance of this optical recording medium at 780 nm incident on the substrate surface of the optical recording medium in accordance with the thickness of the intermediate layer 3. In FIG.
The measurement results are also shown for the case of 00 nm.

According to FIG. 2, this optical recording medium has a large extinction coefficient of 0.79 of the recording layer 2,
It can be seen that the intermediate layer 3 has an appropriate reflectance over a wide range of 100 to 200 nm in thickness, specifically a value in the range of about 65 to 75%.

Further, since the reflectance changes gradually with respect to the thickness of the intermediate layer 3, it is understood that the process management of the film formation is relatively easy.

The optical recording medium has a wavelength of 78 nm.
Using a semiconductor laser of 0 nm, a linear velocity of 1.2 m / sec
c) An EFM modulation signal was recorded at a recording laser power of 8 mW, and the recorded signal was reproduced by a 780 nm semiconductor laser of 0.5 mW.

In each case, the reflectance was reduced at the recording portion, the modulation was sufficiently large, the jitter was good, and almost no distortion was observed in the waveform of the recording / reproducing signal.

This is considered to be because the condition of R is satisfied at the wavelength of 780 nm.

Further, the signal recorded in the same manner was
As a result of reproducing with an output of 0.5 mW of a semiconductor laser of nm, the reflectance was 40% or more and the jitter was good.

This is probably because the condition of T is satisfied at the wavelength of 635 nm.

The reflectance of the optical recording medium having the above structure at 760 nm incident on the substrate surface is 60 to 70%. For these optical recording media, a linear velocity of 1.60 was obtained by using a semiconductor laser having a wavelength of 760 nm. An EFM modulated signal was recorded at a recording laser power of 8 mW at 2 m / sec, and the recorded signal was reproduced by a 760 nm semiconductor laser of 0.5 mW. Although it is acceptable, it seems that there is no practical problem compared to the result of 780 nm, but the result is inferior.

It is considered that this is because the absorption rate A is as large as 40% at the wavelength of 760 nm.

The reflectance of the optical recording medium having the above structure at 750 nm incident on the substrate surface is 60 to 70%, and a semiconductor laser having a wavelength of 750 nm is used for these optical recording media to obtain a linear velocity of 1.70. 2m / sec, recording laser power 8
An EFM modulated signal is recorded at mW, and the recorded signal is
When the data was reproduced with a 50 nm semiconductor laser of 0.5 mW, the reflectance in the recording portion was lowered in each case,
Although the modulation was taken, it seems that there is no practical problem compared with the result of 780 nm, but the result was inferior.

It is considered that this is because the absorption rate A is as large as 40% at the wavelength of 750 nm.

The reflectance of the optical recording medium having the above-mentioned structure at a substrate surface incidence at 600 nm is 60 to 85%, and a semiconductor laser having a wavelength of 600 nm is used for this optical recording medium to produce a linear velocity of 1.2 m. / Sec, recording laser power 8mW
To record an EFM modulated signal, and the recorded signal is
When reproduction was performed with a semiconductor laser of 0.5 mW, the reflectance in the recording portion was lowered in all cases, the modulation was sufficiently large, the jitter was good, and almost no distortion was observed in the waveform of the recording / reproduction signal. Did not.

This is probably because the condition of T is satisfied at a wavelength of 600 nm.

The reflectance of the optical recording medium having the above structure at 550 nm incident on the substrate surface is 70-80%, and a semiconductor laser having a wavelength of 550 nm is used for this optical recording medium. / Sec, recording laser power 8mW
The EFM modulation signal is recorded at
When reproduction was performed with a semiconductor laser of 0.5 mW, the reflectance in the recording portion was lowered in all cases, the modulation was sufficiently large, the jitter was good, and almost no distortion was observed in the waveform of the recording / reproduction signal. Did not.

This is probably because the condition of T is satisfied at the wavelength of 550 nm.

(Comparative Example 1) In this comparative example, Embodiment 1
Recording light with wavelengths 700 and 6
A semiconductor laser of 50 or 635 nm was used.

The optical constant of this recording layer is 700 nm in wavelength.
, The refractive index n3 = 1.40 and the extinction coefficient k3 = 1.6
2 and a refractive index n3 = 1.2 at a wavelength of 650 nm.
8, extinction coefficient k3 = 1.19, refractive index n3 = 0.99 at wavelength 635 nm, extinction coefficient k3 = 0.90
Met.

Therefore, the reflectance R, the transmittance T, and the absorptance A of the laminated film of the recording layer and the intermediate layer are R = 0.39 and T = 0.
27, A = 0.34, and R at a wavelength of 650 nm
= 0.29, T = 0.33, A = 0.38, and at a wavelength of 635 nm, R = 0.29, T = 0.46, A =
0.25.

When the thickness of the intermediate layer is 120 nm, R = 0.38, T = 0.25, and A =
0.37, and R = 0.2 at a wavelength of 650 nm.
9, T = 0.33, A = 0.38, wavelength 635n
m = 0, R = 0.26, T = 0.43, A = 0.31
Met.

When the thickness of the intermediate layer is 140 nm, R = 0.35, T = 0.22, and A =
0.43, and R = 0.2 at a wavelength of 650 nm.
5, T = 0.30, A = 0.45, wavelength 635n
m = 0, R = 0.22, T = 0.41, A = 0.37
Met.

When the thickness of the intermediate layer is 160 nm, R = 0.32, T = 0.20, A =
0.48, and R = 0.2 at a wavelength of 650 nm.
1, T = 0.29, A = 0.50, wavelength 635n
m = 0, R = 0.16, T = 0.41, A = 0.43
Met.

When the thickness of the intermediate layer is 180 nm, R = 0.29, T = 0.20, and A =
0.51 and R = 0.1 at a wavelength of 650 nm.
8, T = 0.29, A = 0.53, wavelength 635n
m = 0, R = 0.12, T = 0.43, A = 0.31
Met.

In the above configuration, since the reflectance was less than 60% and the condition of R or T was not satisfied in the first place, even practically usable recording characteristics could not be obtained.

Further, using the optical recording medium of the first embodiment, a wavelength range of 770 to 830 nm and a wavelength range of 620 to 690 n
Investigating the same wavelength for recording light and reproduction light with m,
When R ≧ 0.5 or T ≧ 0.5 is satisfied, the reflectance is reduced in the recording section, the modulation degree is sufficiently large, and the jitter is low, as in the case of the above-described recording / reproducing at 780 nm. Almost no distortion was observed in the recording / reproducing signal waveform.

In such a case, it was found that it is more preferable that the absorptance A be 30% or less from the viewpoint of the reflection characteristics and the degree of modulation.

The wavelength range of 770 to 830 nm and 6
The case where the reproducing light is shorter than the recording light at 20 to 690 nm is examined. When T ≧ 0.4 or R ≧ 0.4 is satisfied, the recording at the wavelength of 780 nm and the reproduction at the wavelength of 635 nm are performed. As in the result of the above, the reflectance was reduced in the recording portion, the modulation was sufficiently large, the jitter was good, and almost no distortion was observed in the waveform of the recording / reproducing signal.

In such a case, it has been found that the absorptance A is more preferably 50% or less from the viewpoint of the degree of modulation and the like.

In the above, reproduction was repeated 1,000 times, but no change was observed in the reproduction characteristics.

(Embodiment 2) In this embodiment, an optical recording medium was manufactured in the same manner as in Embodiment 1, except that the intermediate layer was formed by a spin coating method using a polysiloxane resin.

In this embodiment, the optical constant of the intermediate layer is
For all wavelengths studied here, the refractive index n4 = 1.
40, the extinction coefficient k4 = 0.

Therefore, the reflectance R, transmittance T, and absorptance A of the laminated film of the recording layer and the intermediate layer are R = 0.58 and T = 0.08 at a wavelength of 780 nm when the thickness of the intermediate layer is 100 nm.
21, A = 0.21 and R at a wavelength of 760 nm
= 0.56, T = 0.06, A = 0.38, and at a wavelength of 750 nm, R = 0.58, T = 0.04, A =
0.38, and R = 0.2 at a wavelength of 635 nm.
3, T = 0.47, A = 0.30, wavelength 550n
m = 0, R = 0.12, T = 0.84, A = 0.04
Met.

The reflectance R, transmittance T, and absorptance A of the laminated film of the recording layer and the intermediate layer are R = 0.56 and T = 0.2 at a wavelength of 780 nm when the intermediate layer thickness is 120 nm.
3, A = 0.21, and R =
0.55, T = 0.06, A = 0.39, wavelength 7
At 50 nm, R = 0.57, T = 0.04, A =
0.39, and R = 0.2 at a wavelength of 635 nm.
3, T = 0.47, A = 0.30, wavelength 550n
m = 0, R = 0.10, T = 0.85, A = 0.05
Met.

The reflectance R, transmittance T and absorptance A of the laminated film of the recording layer and the intermediate layer are R = 0.55 and T = 0.2 at a wavelength of 780 nm when the intermediate layer thickness is 140 nm.
3, A = 0.22, and R =
0.54, T = 0.06, A = 0.40, wavelength 7
At 50 nm, R = 0.57, T = 0.04, A =
0.39, and R = 0.2 at a wavelength of 635 nm.
1, T = 0.45, A = 0.34, wavelength 550n
m = 0, R = 0.07, T = 0.87, A = 0.06
Met.

The reflectance R, transmittance T, and absorptance A of the laminated film of the recording layer and the intermediate layer are R = 0.55 and T = 0.2 at a wavelength of 780 nm when the intermediate layer thickness is 160 nm.
2, A = 0.23, and R =
0.54, T = 0.06, A = 0.40, wavelength 7
At 50 nm, R = 0.57, T = 0.03, A =
0.40, and R = 0.1 at a wavelength of 635 nm.
8, T = 0.43, A = 0.39, wavelength 550n
m = 0, R = 0.04, T = 0.89, A = 0.07
Met.

The reflectance R, transmittance T, and absorptance A of the laminated film of the recording layer and the intermediate layer are R = 0.57 and T = 0.2 at a wavelength of 780 nm when the thickness of the intermediate layer is 180 nm.
0, A = 0.23, and R =
0.55, T = 0.05, A = 0.40, wavelength 7
At 50 nm, R = 0.57, T = 0.03, A =
0.40, and R = 0.1 at a wavelength of 635 nm.
5, T = 0.43, A = 0.40, wavelength 550n
m = R = 0.01, T = 0.92, A = 0.07
Met.

In the optical recording medium having the above-described structure, the 7
The reflectivity at 80 nm was all 60-70%.

The optical recording medium has a wavelength of 78 nm.
Using a semiconductor laser of 0 nm, a linear velocity of 1.2 m / sec
c) An EFM modulation signal was recorded at a recording laser power of 8 mW, and the recorded signal was reproduced by a 780 nm semiconductor laser of 0.5 mW.

As a result, in the recording portion, the reflectance was lowered, the modulation was sufficiently large, the jitter was good, and almost no distortion was observed in the waveform of the recording / reproducing signal.

This is presumably because the condition of R is satisfied at the wavelength of 780 nm.

A signal recorded in the same manner is transmitted at a wavelength of 635 n.
As a result of reproducing with an output of 0.5 mW of semiconductor laser of m
The reflectance was 40% or more, and the jitter was good.

This is considered to be because the condition of T is satisfied at the wavelength of 635 nm.

The reflectance of the optical recording medium having the above structure at 760 nm incident on the substrate surface is 60 to 70%. For these optical recording mediums, a semiconductor laser having a wavelength of 760 nm is used to obtain a linear velocity of 1.70. An EFM modulated signal was recorded at a recording laser power of 8 mW at 2 m / sec, and the recorded signal was reproduced by a 760 nm semiconductor laser of 0.5 mW. Although it is acceptable, it seems that there is no practical problem compared to the result of 780 nm, but the result is inferior.

It is considered that this is because the absorption rate A is as large as 40% at the wavelength of 760 nm.

The reflectance of the optical recording medium having the above structure at 750 nm incident on the substrate surface is 60 to 70%, and a semiconductor laser having a wavelength of 750 nm is used for these optical recording media to obtain a linear velocity of 1.70. 2m / sec, recording laser power 8
An EFM modulated signal is recorded at mW, and the recorded signal is
When the data was reproduced with a 50 nm semiconductor laser of 0.5 mW, the reflectance in the recording portion was lowered in each case,
Although the modulation was taken, it seems that there is no practical problem compared with the result of 780 nm, but the result was inferior.

It is considered that this is because the absorption rate A is as large as 40% at the wavelength of 750 nm.

The reflectance of the optical recording medium having the above-mentioned structure at a substrate surface incidence at 550 nm is 70 to 80%, and a semiconductor laser having a wavelength of 550 nm is used for this optical recording medium to produce a linear velocity of 1.2 m. / Sec, recording laser power 8mW
The EFM modulation signal is recorded at
When reproduction was performed with a semiconductor laser of 0.5 mW, the reflectance in the recording portion was lowered in all cases, the modulation was sufficiently large, the jitter was good, and almost no distortion was observed in the waveform of the recording / reproduction signal. Did not.

This is probably because the condition of T is satisfied at the wavelength of 550 nm.

Further, as in the first embodiment, when the recording light and the reproducing light were examined with the same wavelength in the wavelength range of 770 to 830 nm and 620 to 690 nm, R ≧ 0.5 or T ≧ 0.5 was satisfied. If so, the wavelength 780 described above is used.
As in the case of the recording / reproducing with nm, the reflectance in the recording portion was lowered, the modulation degree was sufficiently large, the jitter was good, and almost no distortion was observed in the waveform of the recording / reproducing signal.

In such a case, it was confirmed that the absorptance A is more preferably 30% or less from the viewpoint of the degree of modulation and the like.

The wavelength range of 770 to 830 nm and 6
When the case where the reproducing light is shorter than the recording light at 20 to 690 nm is also examined, R ≧ 0.4 or T ≧
When the value of 0.4 is satisfied, the reflectance at the recording portion is reduced, the degree of modulation is sufficiently large, and the jitter is also good, as in the case of the recording at the wavelength of 780 nm and the reproduction at the wavelength of 635 nm. Almost no distortion was observed in the waveform of the recording / reproducing signal.

In such a case, it was confirmed that it is more preferable that the absorptance A be 50% or less from the viewpoint of the degree of modulation and the like.

In the above, the reproduction was repeated 1,000 times, but no change was observed in the reproduction characteristics.

(Comparative Example 2) In this comparative example, Embodiment 2
A semiconductor laser having a wavelength of 700 nm was used for both the recording light and the reproduction light for the optical recording medium in the above.

At a wavelength of 700 nm, the reflectance R, transmittance T, and absorptance A of the laminated film of the recording layer and the intermediate layer are R = 0.35, T = 0.27, A when the intermediate layer thickness is 100 nm.
= 0.38, and when the thickness of the intermediate layer is 120 nm, R =
0.35, T = 0.26, A = 0.39, and when the intermediate layer thickness is 140 nm, R = 0.34, T = 0.25,
A = 0.41, and when the thickness of the intermediate layer is 160 nm, R
= 0.32, T = 0.23, A = 0.45, and when the thickness of the intermediate layer is 180 nm, R = 0.30 and T = 0.2
2, A = 0.48.

In each case, the reflectivity was less than 40%, and there was no case where the condition of R or T was satisfied in the first place, so that even practically usable recording characteristics could not be obtained.

(Embodiment 3) In this embodiment, as an intermediate layer, ZrO ₂ is formed to a thickness of 100 by a vacuum evaporation method.
An optical recording medium was produced in the same manner as in Embodiment 1, except that the film was formed to have a thickness of 120 nm.

In the present embodiment, the optical constant of the intermediate layer is
The refractive index n4 = 2.
21, the extinction coefficient k4 = 0.

Therefore, the reflectance R, the transmittance T, and the absorptance A of the laminated film of the recording layer and the intermediate layer are R = 0.22 and T = 0.02 at a wavelength of 600 nm when the intermediate layer thickness is 100 nm.
51, A = 0.27, and R at a wavelength of 550 nm
= 0.19, T = 0.73, A = 0.08.

When the thickness of the intermediate layer is 120 nm, R = 0.07, T = 0.60, A =
0.33, and R = 0.0 at a wavelength of 550 nm.
1, T = 0.91 and A = 0.08.

In the optical recording medium having the above-described structure, the light incident on the substrate surface 6
The reflectance at 00 nm was 70-80%.

The optical recording medium has a wavelength of 60.
Using a semiconductor laser of 0 nm, a linear velocity of 1.2 m / sec
c) An EFM modulated signal was recorded at a recording laser power of 8 mW, and the recorded signal was reproduced with a 600 nm semiconductor laser of 0.5 mW.

As a result, in the recording portion, the reflectance was lowered, the modulation was sufficiently large, the jitter was good, and almost no distortion was observed in the waveform of the recording / reproducing signal.

This is probably because the condition of T is satisfied at a wavelength of 600 nm.

The reflectance of the optical recording medium having the above structure at 550 nm upon incidence on the substrate surface was 70 to 80%.

Then, a semiconductor laser having a wavelength of 550 nm was used for all these optical recording media, and a linear velocity of 1.2 m was used.
The EFM modulation signal was recorded at a recording laser power of 8 mW / sec, and the recorded signal was reproduced by a 550 nm semiconductor laser of 0.5 mW.

As a result, in the recording portion, the reflectance was lowered, the modulation was sufficiently large, the jitter was good, and almost no distortion was observed in the waveform of the recording / reproducing signal.

This is considered to be because the condition of T is satisfied at the wavelength of 550 nm.

Further, similarly to the first embodiment, when the recording light and the reproducing light have the same wavelength in the wavelength range of 770 to 830 nm and 620 to 690 nm,
When the case where the reproduction light was shorter than the recording light at 830 nm and 620 to 690 nm was examined, similar results were obtained.

(Comparative Example 3) In this comparative example, Embodiment 3
A semiconductor laser having a wavelength of 700 nm was used for both recording light and reproduction light for an optical recording medium having an intermediate layer having a thickness of 100 nm.

Here, the reflectance R, the transmittance T, and the absorptance A of the laminated film of the recording layer and the intermediate layer are R = 0.41 and T = 0.
19, A = 0.40.

Since the reflectivity was less than 40% and did not satisfy the above conditions, good recording and reproduction could not be performed.

[0164]

As described above, according to the structure of the present invention,
By using an optical recording medium in which at least a recording layer containing a dye that absorbs recording light, an intermediate layer, and a reflective layer are sequentially formed on a transparent substrate, good recording and reproduction can be performed with respect to light having a predetermined wavelength. Possible optical recording media and optical recording / reproducing methods can be provided.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a write-once optical recording medium according to a first embodiment of the present invention.

FIG. 2 is a view showing the relationship between the thickness of an intermediate layer and the reflectance of the write-once type optical recording medium.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Transparent substrate 2 Recording layer 3 Intermediate layer 4 Reflective layer 5 Protective layer

Claims (15)

[Claims] 1. A transparent substrate, a recording layer provided on the substrate and containing a dye that absorbs recording light, an intermediate layer provided on the recording layer, and a reflection layer provided on the intermediate layer R, the reflectance when light is incident from the recording layer side of the laminated film including the recording layer and the intermediate layer at the recording wavelength of the recording light and the reproduction wavelength of the reproduction light, and the transmittance is T.
Assuming that the absorption rate is A (R + T + A = 1), R ≧ 0.5
Optical recording medium that satisfies the following. 2. A transparent substrate, a recording layer provided on the substrate and containing a dye that absorbs recording light, an intermediate layer provided on the recording layer, and a reflection layer provided on the intermediate layer. R, the reflectance when light is incident from the recording layer side of the laminated film including the recording layer and the intermediate layer at the recording wavelength of the recording light and the reproduction wavelength of the reproduction light, and the transmittance is T.
When the absorption rate is A (R + T + A = 1), T ≧ 0.5
Optical recording medium that satisfies the following. 3. The optical recording medium according to claim 1, wherein the absorptance A is 30% or less. 4. The reflectance when light is incident from the recording layer side of the laminated film composed of the recording layer and the intermediate layer at the reproduction wavelength of the reproduction light shorter than the recording wavelength of the recording light, and the transmittance is R ′. T 'and the absorption rate as A' (R '+ T' +
4. The optical recording medium according to claim 1, wherein A ′ = 1) and R ′ ≧ 0.4 are satisfied. 5. The reflectance when light is incident from the recording layer side of the laminated film including the recording layer and the intermediate layer at the reproduction wavelength of the reproduction light shorter than the recording wavelength of the recording light, and the transmittance is R ′. T 'and the absorption rate as A' (R '+ T' +
4. The optical recording medium according to claim 1, wherein A '= 1) and T' ≧ 0.4 are satisfied. 6. A transparent substrate, a recording layer provided on the substrate and containing a dye that absorbs recording light, an intermediate layer provided on the recording layer, and a reflection layer provided on the intermediate layer And the reflectance is R ′ and the transmittance is T ′ when light is incident from the recording layer side of the laminated film including the recording layer and the intermediate layer at a reproduction wavelength of the reproduction light shorter than the recording wavelength of the recording light. ′, When the absorption rate is A ′ (R ′ + T ′ + A ′ =
1) An optical recording medium satisfying R ′ ≧ 0.4. 7. A transparent substrate, a recording layer provided on the substrate and containing a dye that absorbs recording light, an intermediate layer provided on the recording layer, and a reflection layer provided on the intermediate layer And the reflectance is R ′ and the transmittance is T ′ when light is incident from the recording layer side of the laminated film including the recording layer and the intermediate layer at a reproduction wavelength of the reproduction light shorter than the recording wavelength of the recording light. ′, When the absorption rate is A ′ (R ′ + T ′ + A ′ =
1) An optical recording medium satisfying T ′ ≧ 0.4. 8. The absorption rate A ′ is 50% or less.
8. The optical recording medium according to any one of items 1 to 7. 9. The method according to claim 1, wherein the reflection layer is a metal layer.
The optical recording medium according to any one of the above. 10. The optical recording medium according to claim 1, further comprising a protective layer outside the reflective layer. 11. An optical recording method for recording information by irradiating the optical recording medium according to claim 1 with a laser beam having a wavelength range of 770 to 830 nm. 12. An optical recording method for recording information by irradiating the optical recording medium according to claim 1 with laser light having a wavelength range of 620 to 690 nm. 13. An optical reproducing method for reproducing recorded information by irradiating the optical recording medium according to claim 1 with a laser beam having a wavelength range of 770 to 830 nm. 14. An optical reproducing method for reproducing recorded information by irradiating the optical recording medium according to claim 1 with laser light having a wavelength range of 620 to 690 nm. 15. Using the optical recording medium according to any one of claims 4 to 10, irradiating laser light having a wavelength range of 770 to 830 nm or 620 to 690 nm to record information, and recording the information in a wavelength range of 770 to 830 nm or 620-690
An optical recording / reproducing method for reproducing recorded information by irradiating a laser beam of nm with a wavelength shorter than the wavelength of the recording light.