JPS58181688A - Optical recording medium - Google Patents

Abstract

PURPOSE:To obtain an optical recording medium having a stable organic thin film with respect to heat with an absorption band on long wavelength side by providing an organic thin film containing a specified pyrylium dye in an optical recording medium for laser writing and recording. CONSTITUTION:An organic thin film 2 containing 1-90wt%, preferably 20- 70wt% of pyrylium dye as given by formula (where, X represents S, O or Se atom, Z hydrocarbon group comprising atom groups necessary for completing pyrylium, this pyrylium or the like allowed to be substituted, R1 and R2 hydrogen atom, alkyl group, aryl group, styryl group, R3 aryl group or heterocyclic group substituted or unsubstituted and A<(-)> anion) is formed on a substrate 1 at the dry thickness of less than 10mum. A reflecting layer 3 made of a reflective metal is provided between the substrate 1 and the organic thin film 2.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical recording medium suitable for writing and recording with a laser, particularly a semiconductor laser, and more particularly to an improved optical recording medium usable in original disk technology.

Generally, optical disks consist of optically detectable small (e.g., about 1 μm) formed in a thin recording layer on a substrate.
) The bits can be in the form of spiral or circular tracks to store high-density information.1 To write information on such a disk, a focused laser is scanned over the surface of the laser-sensitive layer, and this Only the surface irradiated by the laser beam forms the bit, which is formed in the form of a spiral or circular track. Laser sensitive: - C. Can absorb laser energy to form optically detectable bits. For example, in a heat mode recording method, the laser sensitive layer absorbs thermal energy and can form small recesses (bits) at that location by evaporation or melting. In another heat mode recording method, the absorption of the irradiated laser energy can form a bit with an optically detectable density difference at that location.

It is detected by scanning along the track and noting the optical changes in the areas where bits are formed and the areas where no bits are formed. For example, a laser is scanned along the trunk and the energy reflected by the disk is monitored by a photodetector. When a bit is not formed, the output of the photodetector is reduced, while when a bit is formed, the laser beam is sufficiently reflected by the underlying reflective surface and the output of the photodetector is increased.

As recording media for use in such optical discs, media that mainly use inorganic materials such as metal thin films such as aluminum evaporated films, bismuth thin films, tellurium oxide thin films, and cal-genite amorphous glass films have been proposed so far. . These thin films are generally sensitive to light with wavelengths around 350 to 600 nm, and also have drawbacks such as high reflectance to laser light and low utilization of laser light. , in recent years relatively long wavelengths (e.g. 780
Research is being carried out on organic thin films whose optical properties can be changed by light energy of nanometers (nm or more).

Such an organic thin film is effective in that bits can be formed using a semiconductor laser whose oscillation wavelength is around 830 nm, for example.

However, organic compounds that generally have absorption characteristics on the long wavelength side are unstable to heat and have technical problems in terms of sublimation, so it is not always possible to develop organic thin films that are satisfactory in terms of properties. The current situation is that it cannot be said that this is true.

An object of the present invention is to provide an optical recording medium having an organic thin film having an absorption band t on the long wavelength side.

Another object of the present invention is to provide an optical recording medium having an organic thin film that is stable against heat. C, which has a characteristic at a point.

General formula il+ ni-9 In the formula, X represents a sulfur atom, an oxygen atom or a selenium atom.

2 is optionally substituted biryllium, thiopyrylium,
Selenapyryllium, benzobyrylium, benzothiopyryllium, benzoselenapyrylium, naphtopyrylium,
Indicates a hydrocarbon group consisting of the atomic group necessary to complete naphthothiopyrylium or naphthoselenapyrylium. Examples of substituents include halogen atoms such as chlorine atom, bromine atom, and fluorine atom, alkyl groups such as methyl, ethyl, propyl, inglovil, butyl, t-butyl, amyl, isoamyl, hexyl, octyl, nonyl, and dodecyl, phenyl, Aryl groups such as α-naphthyl and β-naphthyl,
Tolyl, xylyl, biphenyl, ethylphenyl, methoxyphenyl, ethoxyphenyl, amyloxyphenyl, dimethoxyphenyl, jetoxyphenyl, hydroxyphenyl, chlorophenyl, dichlorophenyl, bromophenyl, dibromophenyl, nitrophenyl, diethylaminophenyl, dimethylaminophenyl, dimethyl Substituted aryl groups such as benzylaminophenyl, styryl,
Examples include substituted or unsubstituted styryl groups such as chlorosteryl, dimethylaminostyryl, diethylaminostyryl, diethylaminostyryl, dibutylaminostyryl, dibenzylaminostyryl, diphenylaminostyryl, methoxystyryl, and ethoxystyryl.

R, and Peng are each (11) water bulk atom + bl alkyl group, especially alkyl group having 1 to 15 carbon atoms: for example, methyl, ethyl, propyl, inpropyl, butyl, t-butyl, amyl, isoamyl, hexyl, Octyl, nonyl, dodecyltel 71J-ru group: phenyl, α-naphthyl, β
-Naphthyl + al l Substituted aryl group Nitrile, xylyl, biphenyl, ethylphenyl, methoxyphenyl, ethoxyphenyl, amiαxyphenyl, dimethoxyphenyl, jetoxyphenyl, hydroxyphenyl, chlorophenyl, dichlorophenyl, bromophenyl, dibromophenyl, nitrophenyl, diethylamino Phenyl, dimethylaminophenyl, dibenzylaminophenyl (11) styryl group nistyryl ill styryl group chlorostyryl, dichlorosteryl, methylstyryl, dimethylsteryl, methoxysteryl, ethoxystyryl, dimethylaminostyryl, diethylaminostyryl , diethylaminostyryl, dibutylaminosteryl, dibenzylaminostyryl, diphenylaminostyryl R8 is a substituted or unsubstituted aryl group (phenyl,
α-naphthyl, β-f7f, tolyl, xylyl, biphenyl, ethylphenyl, dieternoenyl, methoxyphenyl, dimethoxy7xyl, trimethoxyphenyl, ethoxyphenyl, jetoxyphenyl, amyloxyphenyl, hydroxyphenyl, chlorophenyl, dichlorophenyl, trichlorophenyl, bromophenyl,
dibromophenyl, tribromophenyl, nitrophenyl, dimethylaminophenyl, diethylaminophenyl, dibenzylaminophenyl, diphenylaminophenyl) and V′i-substituted or unsubstituted heterocyclic groups (3-carbazolyl, 9-methyl-3-carbazolyl) , 9-ethyl-a-carbazolyl, 7-ethyl-3-carbazolyl, 2-pyridyl, 4-pyridyl, 2-quinolyl, 4-quinolyl 3-indolyl, 2-phenyl-3-1
methyl-2-phenyl-3-indolyl). and - are hydrogen atoms or alkyl groups (methyl, ethyl, propyl, butyl, amyl, hexyl,
octyl, nonyl), m represents l or 2,
n represents 0.1 or 2.

However, when n is 2, each R4 may be the same or different, and each R4 may be the same or different.

A9 represents an anion such as verchlorate, fluoroborate, iodide, chloride, bromide, sulfate, periodide, P-)luenesulfonate, and the like.

Representative pyrylium dyes represented by the general formula il+ are as follows.

Compound Mu Compound Example (1) C10,e C10,e (B104e C104θ to4e ceoθ NingCeO4'・Peo4e C10,e Cto4θ cto4e (To) ceo,e C!υ C10,θ C10,e CIO4θ Cto,θ - 104e or ClO4θ The biryllium dye of the present invention can be obtained, for example, by reacting 2,6-diphenyl-4-methylthiopyrylium salt with 4-/1 dimethylaminobenzaldehyde. Can be carried out in acid.

1) When carried out in the presence of an amine. At this time, various solvents are used as solvents, especially alcohols such as ethanol, nitriles such as acetonitrile, Q ketones such as methyl ethyl ketone, nitro compounds such as nitrobenzene, halogenated hydrogen dihydrides such as tetrachloroethane, etc. are used, preferably alcohols such as ethanol.

Examples of amines include primary, secondary and tertiary alkyl amines having 1 to 25 carbon atoms such as piperidine, triethylamine and hexylamine, aromatic amines having 6 to 25 carbon atoms such as aniline and dimethylaniline, and pyridine and quinoline. A nitrogen-containing unsaturated multicyclic compound is used.

The amount of amine is 0.1 to 1 mole of thiopyrylium salt.
10 mol is used, preferably 0.5 to 2 mol. Also, a large excess of amine may be used as a solvent. The reaction time is 30 minutes to 10 hours, preferably 1 hour to 3 hours, and the reaction temperature is from around 50°C to the reflux temperature g of the solvent or amine, preferably around the reflux temperature. Amount of solvent Vi2.6-diphenyl-4-methylthiopyrylium salt 1.9 to 1 to loOm/.

Preferably, U3-10m1 is used.

11) When the reaction is carried out in carboxylic anhydride.

The amount of carboxylic anhydride, such as acetic anhydride, is 1 to 20 per gram of 2,6-diphenyl-4-methylthiopyrylium salt.
ml, preferably Vi2-10m/. Reaction time ii is 1 minute to 1 hour, preferably 3 to 20 minutes. The reaction temperature ranges from around 80'O to reflux temperature (140°C), preferably around 100υ.

An example of synthesis of a typical biryllium salt used in the present invention will be shown.

Synthesis example 1. (Byrylium in #Example A (45)) 2.6
-diphenyl-4-methylpyrylium Berkroley) 5
．． 0.9 and 4-dimethylaminobenzaldehyde 3.7
Heat the g. Next, the precipitate obtained by cooling was allowed to cool and was recrystallized from acetic acid/acetic anhydride = Vl to obtain a dye of 1.89.

Melting point 271-272℃ Elemental analysis Molecular formula C,, HuO, NC/calculated value (
弼 Experimental value C67,8568,01 H5,07! Lll N 2.93 2.88 Synthesis Example 2. (
1
．． 41 was dispersed in 150 m of acetone, a solution of sodium sulfide lI dissolved in 10 m of water was added, and the mixture was stirred for 2 minutes. To this solution were added 15 m/ml of 20% perchloric acid and 150 me/ml of water, stirred for 1 hour, and allowed to stand. After passing through the precipitate, add vinegar
! 1! / acetic anhydride = 1/1 and recrystallize dye 1. l
, @0 melting point 277-281.5℃ Elemental analysis Molecular formula ~ to Q, NC/S calculated value (@
Experimental value (@ 0 85.64 65.88H4,914
, 84 S 6.49 6.56 The optical recording medium of the present invention can have a structure as shown in FIG. 1, for example. The optical recording medium shown in FIG. 1 can be formed by providing an organic thin film 2 containing the above-described beryllium dye on a substrate l.

As the substrate 1, polyester, acrylic resin, polyolefin resin, phenol resin, glass stick, glass, metals, or the like can be used. organic thin film 2
can be formed by vacuum deposition of the aforementioned cyanine dye,
It can also be formed by containing the above-mentioned 77 dye in the inder and applying a coating liquid to the substrate 21.When forming a thin film on the binder and the cyanine dye, Suitable binders for the cyanine dyes, which may be contained in a dispersed state or in an amorphous state in the binder, can be selected from a wide range of resins. are nitrocellulose, phosphorous cellulose, cellulose sulfate, cellulose acetate, cellulose propionate, M [cellulose, cellulose myristate, cellulose palmitate, cellulose acetate s-propionate, cellulose esters of cellulose acetate and butyrate, methyl cellulose, Ethylcellulose, Flobilcellulose, Cellulose ethers of fluorcellulosenato, polystyrene,
Polyvinyl chloride, polyvinyl acetate, polyvinyl vinyl
-ol, polyvinyl acetal, polyvinyl alcohol,
Vinyl wag such as polyvinylpyrrolidone, sterene-butadiene copolymer, styrene-acrylonitrile copolymer, styrene-butadiene-acrylonitrile copolymer, vinyl chloride-vinylidene chloride copolymer, vinyl chloride-vinyl acetate copolymer and other aggregate polymers,
Acrylic resins such as polymethyl methacrylate, polymethyl acrylate, polybutyl acrylate, polyacrylic acid, polymethacrylic acid, polyacrylamide, polyacrylonitrile, etc. Polyesters such as polyethylene terephthalate/LIA% Poly(4,4'-iso glopylidene diphenylene-1,4-cyclohexylene dimethylene carbonate), poly(ethylenedioxy-
3,3'-phenylene thiocarbonate), poly(4,
4'-isopropylidene diphenylene carbonate coated terephthalate), poly(4,4'-isopropylidene diphenylene carbonate), poly(4,4'-5
polyarylate resins such as ee-)゛tylidene diphenylene carbonate), isu (4,4'-isopropylidene diphenylene carbonate-block-oxyethylene), polyamides, polyimides, epoxy resins, Phenol resins, polyolefins such as polyethylene, polypropylene, chlorinated polyethylene, etc. can be used.

The organic solvent used during coating varies depending on the type of binder and whether the cyanine dye is in a dispersed state or in an amorphous state in the binder, but in general, alcohols such as methanol, ethanol, isopropanol, etc. Ketones such as acetone, methyl ethyl ketone, and cyclohexanone, amides such as N,N-dimethylformamide and N,N-dimethylacetamide, sulfoxides such as dimethyl sulfoxide, and ethers such as tetrahydrofuran, diochitin, and ethylene glycol monomethyl ether. ! ,vinegar! Esters such as methyl and ethyl acetate, chloroform, methylene chloride, dichloroethylene,
It is possible to use aliphatic--orogenated reconstituted water such as carbon tetrachloride and trichlorethylene, aromatics such as benzene, toluene, xylene, ligroin, monochlorobenzene, dichlorobenzene, methyl cellosolve, and the like.

Coating methods include dip coating, spray coating, spinner coating, bead coating,
This can be carried out using a coating method such as a Mayer bar coating method, a blade coating method, a roller coating method, or a curtain coating method.

The above-mentioned bi-IJ-IJ dye contained in the organic thin film 2 is
1 to 90 weight-1 preferably t-1 in organic thin film 2
20 to 70 fLll-. Further, the dry thickness of the organic thin film 2 is 10 microns or less, preferably 2 microns or less.

Further, in the optical recording medium of the present invention, a reflective layer 3 can be provided between the substrate 1 and the organic thin film 2, as shown in FIG.

The reflective layer 3 can be a vapor-deposited layer or a non-metallic layer of a reflective metal such as aluminum, silver, chromium, etc.

The organic thin M2 can be formed into bits 5 by irradiation with a focused laser beam 4 as shown in FIG. When the depth of the bit 5 is made equal to or greater than the thickness of the organic thin film 2, the reflectance in the bit region can be increased. When reading, if a laser beam having the same wavelength as the laser beam used for writing but with low intensity is used, the reading light is largely reflected in the bit area, but is absorbed in the non-bit area. Another method is to perform real-time writing with a laser beam of a first wavelength that is absorbed by the organic thin film 2, and use a laser beam of a second wavelength that substantially passes through the organic thin film 2 for reading. be. The WIt laser beam can respond to changes in the reflective layer caused by different film thicknesses in bit and non-bit regions.

The optical recording medium of the present invention can be produced using an argon laser (excavation wavelength 4
811 nm), helium-neon laser (excavation wavelength 63 nm), helium-neon laser (excavation wavelength 63 nm),
3 nm), helium-cadmium laser (oscillation wavelength 44 nm), helium-cadmium laser (oscillation wavelength 44
It is also possible to record by irradiation with a gas laser such as 2 nm), but it is preferable to use a laser with a wavelength of 750 nm or more, or a near-infrared laser (oscillation wavelength 830 nm), which has an oscillation wavelength in the infrared region. A recording method using laser beam irradiation is suitable. Furthermore, the aforementioned radar beam can be used for reading. In this case, writing and reading can be performed using a four-wavelength laser, or can be performed using lasers having different wavelengths.

According to the present invention, a ratio that is desired to be sufficiently improved can be obtained, and the organic thin film used in the present invention has small reciprocity law failure, making it possible to increase the utilization of intense energy beams such as laser beams. . Furthermore, it is possible to perform recording using a laser beam mK having an oscillation wavelength of 750 mm or more.

Hereinafter, the present invention will be explained in detail according to examples.

Example 1 12 parts by weight of nitrocellulose solution (manufactured by Daicel Chemical Industries, Ltd.; overlace lacquer nitrocellulose 25 wt% methyl ethyl ketone solution), 3 parts by weight of the thiopyrylium dye A (9), and 15 parts by weight of the thiopyrylium dye A (9).
0 parts by weight mixed with a trowel, melted round. This solution was coated on a Pyrex substrate by a 500 rpm spinner coating method, and then dried at a temperature of 100° C. for 2 hours to obtain a recording layer of 0.71/wl.

The optical recording media created in this way are placed on a turntable, and the turntable is moved by a motor.
Recording is performed by irradiating the surface of the recording layer with a track-shaped gallium-aluminum semiconductor laser beam (excavation wavelength 830 nm) of 95 mW and 8 mm focused to a spot size of 0.8 pm while giving a rotation of pm. .

When the surface of this recorded optical disc was observed with a scanning electronic order II mirror, clear bits were observed. When a low-power gallium-aluminum-arsenide semiconductor laser was incident on this optical disk and the reflected light was detected, a waveform with a sufficient SZN ratio was obtained.

Example 2 Nitrocellulose 1llH [(manufactured by Daicel Chemical Industries, Ltd.);
Oats - Les Rucker, Nido O - Luloose 25w
t% methyl ether ketone solution) IO parts by weight (2
3 parts by weight of the thiopyrylium dye (9) was mixed with 100 parts by weight of monochlorobene and thoroughly stirred to dissolve it.Then, this solution was coated on a Pyrex substrate with tic 5
Coating amount after drying at 00 rpm is 0.6 i/11
After coating with a spinner so as to obtain a temperature of t, the recording layer was dried at a temperature of 100° C. for 2 hours to form a recording layer. When this recording layer was irradiated with the same laser beam as in Example 1, the same results as in Example 1 were obtained.

Example 3 50G of the benzobylylium dye A(3) was placed in a molybdenum boat for vapor deposition, evacuated to less than 1×1O″@mm, and then vapor-deposited on a Pyrex substrate.

A friend who controls IK heaters that do not rise. In this way, an organic thin film was formed on the Pyrex substrate to produce an optical recording medium. When the recording layer made of this organic thin film was irradiated with the same laser beam as in Example 1, the same results as in Example 1 were obtained.

Example 4 Cannot be used in Example 1! +9) Instead of the thiopyrylium dye, the naphthopyrillium dye of Mua◆ was used.
When an optical recording medium was prepared in exactly the same manner as in Example 1 and then irradiated with the same laser beam, the same results as in Example 1 were obtained.

Example 5 An optical recording medium was prepared in exactly the same manner as in Example 1, except that instead of the thiopyrylium dye of 9A (9) used in Example 1, the biryllium dye of mail) was used.
When the same laser beam was irradiated, the same results as in Example 1 were obtained.

Example 6 An optical recording medium was prepared in exactly the same manner as in Example 1 except for using a naphthothiopyrylium dye of MuQ4 in place of the thiopyrylium dye A+9) used in Example 1. , when irradiated with a similar laser beam, Example 1
Similar results were obtained.

Example 7 An optical recording medium was prepared in exactly the same manner as in Example 1, except that the thiopyrylium dye of Mu (1) was used in place of the thiopyrylium dye of Mu (9) used in Example 1. When the same laser beam was irradiated, the same results as in Example 1 were obtained.

Example 8 In place of the 9um (9) thiopyrillium dye used in Example 1, a 7fI @ selenapyrillicum dye was used.
When an optical recording medium was prepared in exactly the same manner as in Example 1 and then irradiated with the same laser beam, the same results as in Example 1 were obtained.

Example 9 In place of the thiopyrylium dye 9A (9) used in Example 1, theopyryllium dye Ac119 was used.
In case 1, when an optical recording medium was prepared in exactly the same manner as in Example 1 and then irradiated with the same laser beam, the same results as in Example 1 were obtained.

Example 1O In place of the thiopyrylium dye 9 (9) used in Example 1, a thiopyrylium dye AC31 was used.
An optical recording medium was prepared in exactly the same manner as in Example 1 and then irradiated with the same laser beam, and the same results as in Example 1 were obtained.

Example 11 An optical recording medium was prepared in exactly the same manner as in Example 1, except that the thiopyrylium dye of Aft3 was used in place of the thiopyrylium dye of /K(@ used in Example 1, and then the same method was used. When irradiated with a laser beam, the same results as in Example 1 were obtained.

Example 12 In place of the thiobium(9) dye used in Example 1, the biryllium dye of A(c) was used to produce 911 or f.
An optical recording medium was prepared in exactly the same manner as in Example 1 and then irradiated with the same laser beam, and the same results as in Example 1 were obtained.

[Brief explanation of the drawing]

1 and 2 are cross-sectional views of the optical recording medium of the present invention, and FIG. 3 is an explanatory view showing an embodiment using the optical recording medium of the present invention. 1: Substrate 2: Organic thin film 3: Reflective layer 4: Laser beam 5: Hanging tip M 536-

Claims (1)

[Scope of Claims] An optical recording medium characterized by having an organic thin film containing a biryllium dye represented by the following general formula (ri). General formula ill , + --------2----, -~, where X represents a sulfur atom, an oxygen atom, or a selenium atom. Z: [From the atomic group necessary to complete biryllium, thiopyrylium, selenapyrylium, benzobyrylium, benzothiopyrylium, benzoselenapyrylium, naphthopyryllium, naphthothiopyrylium or naphthoselenapyrylium] This shows a swelling hydrogen group. R1 and bird: represents a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted styryl group. R: represents a substituted or unsubstituted aryl group or a substituted or unsubstituted heterocyclic group.搗 and R: represent a water bulky atom or an alkyl group. AQ: ##h Ion store. m: indicates l or 2. n: indicates 0, 1 or 2. However, when n is 2, the birds may be the same or different, and the birds may be the same or different.