JPH07125434A - Optical recording medium - Google Patents

Abstract

PURPOSE:To obtain a write-once optical disk enabling low power recording and having a high carrier level, in an optical recording medium using an Si- phthalocyanine dye as a recording film material, by adding an epoxy resin to a recording film. CONSTITUTION:In an optical recording medium having a recording film containing an Si-phthalocyanine dye represented by general formula {wherein R is a hydrogen atom, a 12-21C linear chain alkyl group, SO2NH-(CH2)3-N-(C2 H5)2, SO<2>NH-(CH2)3-N-(CH3)2 or O-(CH2)19OH}, an epoxy resin is added to the recording film. By this constitution, as compared with a conventional recording medium having a recording film containing only the Si-phthalocyaine dye, recording can be performed by the same power and recording amplitude is large and a carrier can be enhanced. Further, enrivonmental resistance as an optical recording medium can be improved.

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, and more particularly to an optical recording medium using a Si-phthalocyanine dye as a recording film material.

[0002]

2. Description of the Related Art In recent years, write-once optical disks such as OMD, CD-R and LD-R have been put to practical use, and cyanine dyes and phthalocyanine dyes have been developed as recording film materials for these write-once optical disks. Has been used.

Here, a write-once type optical disc using a cyanine dye or a phthalocyanine dye as a recording film material is
Since recording with low power is difficult, the recording system becomes large,
There are problems such as high price and hindering its popularization for general consumers.

Therefore, the applicant of the present application has developed a write-once type optical disk capable of recording at low power by using a Si-phthalocyanine dye as a recording film material and has already filed an application (Japanese Patent Application No. 5- 9525).

[0005]

However, the write-once type optical disc using the Si-phthalocyanine dye as the recording film material has a problem that the recording amplitude is small and the carrier level is low.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a write-once type optical disc capable of recording at a low power, having a large recording amplitude and a high carrier level.

[0007]

Means for Solving the Problems As a result of intensive studies to achieve the above-mentioned object, the present inventors have found that a recording film of a write-once optical disc is prepared by using a dye solution containing a Si-phthalocyanine dye as an epoxy resin solution. It was found that a write-once optical disc with a high recording amplitude, a large recording amplitude, and a high carrier level can be obtained by forming a mixed recording film material with a high recording power, and the environmental resistance is also improved. The present invention has been completed by discovering that.

That is, the optical recording medium of the present invention is an optical recording medium having a recording film containing a Si-phthalocyanine dye represented by the following chemical formula (1), wherein the recording film contains an epoxy resin. There is.

[0009]

[Chemical 1]

[0010]

In the optical recording medium of the present invention, since the recording film of the optical recording medium is configured to contain the Si-phthalocyanine dye and the epoxy resin, the conventional recording film containing only the Si-phthalocyanine dye is used. Recording can be performed with the same power, the recording amplitude is large, and the carrier level is high, as compared with the optical recording medium. Also, the environment resistance as an optical recording medium is high.

The optical recording medium of the present invention will be described in detail below. The optical recording medium of the present invention has a recording film containing a Si-phthalocyanine dye and an epoxy resin.

Here, the Si-phthalocyanine dye is
It is represented by the following chemical formula (1).

[0013]

[Chemical 1] [However, in the formula (1), R is a hydrogen atom, carbon number 1
A linear alkyl group having _{2~21, SO 2 NH- (CH 2} ) 3
_{-N- (C 2 H 5) 2} , SO 2 NH- (CH 2) 3 -N
- (CH ₃₎ represents either ₂ or O- (CH _{2) 19} -OH. The Si-phthalocyanine dye represented by the above formula (1) is different from the dye-based optical recording medium that has been often used conventionally, in that the dye-based optical recording medium causes an association state by irradiation with light. Therefore, recording / reproducing is performed by utilizing the difference in light reflectance or transmittance between the recording portion in the association state and the non-recording portion in the non-association state.

As the solvent used in the dye solution containing the Si-phthalocyanine dye, various known solvents can be used, for example, tetrafluoropropanol,
Methanol, isophorone, ethyl cellosolve, methyl cellosolve, diacetone alcohol, cyclohexanone,
1,2-dichloroethane etc. are mentioned.

The epoxy resin mixed with the Si-phthalocyanine dye is not particularly limited as long as it is a resin having an epoxy group. For example, bisphenol A
Examples thereof include bisphenol-based epoxy resins, glycerin-type epoxy resins, novolac-type epoxy resins, alicyclic epoxy resins, and polyolefin-type epoxy resins, which are obtained by polycondensation of and epichlorohydrin. Among these, it is preferable to use a bisphenol epoxy resin.

The glass transition point of these epoxy resins is preferably 50 to 150 ° C. As the solvent used for the epoxy resin solution, various known solvents are used, and examples thereof include 2-ethoxyethanol, 2-methoxyethanol, isophorone, and cyclohexanone.

The volume mixing ratio of the epoxy resin solution in the recording film forming material obtained by mixing the epoxy resin solution with the dye solution containing the Si-phthalocyanine dye is preferably 5 to 40%, more preferably 10%. ~ 3
It is 0%.

When the volume mixing ratio of the epoxy resin solution is 5% or less, a sufficient effect of mixing the epoxy resin cannot be expected, and when the volume mixing ratio is 40% or more, the performance as a recording film is affected. .

The method for forming the recording film containing the Si-phthalocyanine dye and the epoxy resin is not particularly limited, but for example, a recording film forming material obtained by mixing an epoxy resin solution with a dye solution containing the Si-phthalocyanine dye is used. It can be formed by a spin coating method, a roll coating method, a spray coating method or the like.

The thickness of the recording film is usually 10 to 1000 n.
It is about m. The other structure of the optical recording medium of the present invention is not particularly limited, and may be, for example, a so-called single-layer film structure in which a recording film is formed on a light transmissive substrate, or further formed on the recording layer. It may have a structure in which a reflective film layer and a protective film layer are provided.

Here, the light transmissive substrate has a disk shape, and on one side of the substrate, tracking prepits or pregrooves are usually formed concentrically or spirally. Substrates having such pre-pits or pre-grooves include, for example, polycarbonate resin (PC), polymethylmethacrylate resin (PMMA), amorphous polyolefin resin (AP
O), an injection-molded resin substrate integrally formed of a transparent resin material such as an epoxy resin, a glass substrate, or the like. Further, the substrate is not limited to the integrally formed injection-molded resin substrate, and may be a substrate formed by a so-called 2P (photo-polymer) method. The thickness of such a substrate is usually 1.
It is about 0 to 1.5 mm.

The light reflecting film which may be provided on the recording film is made of a metal such as Au, Al, Ag or Cu, which is formed by a vacuum vapor deposition method, a sputtering method, an ion plating method or the like. It is formed into a film.

The protective film which may be provided on the light reflecting film is generally formed by applying an ultraviolet curable resin by a spin coating method and then irradiating it with ultraviolet rays to cure the coating film. Is. In addition, epoxy resin, acrylic resin, silicone resin, urethane resin and the like are also used as the material for forming the protective film.

[0024]

EXAMPLES The present invention will be described in more detail below with reference to examples. Preparation of optical recording medium Si-phthalocyanine represented by the following formula (2)
30 in 2,3,3-tetrafluoro-1-propanol solvent
a dye solution dissolved at a ratio (concentration) of mg / ml,
100m epoxy resin in 2-ethoxyethanol solvent
Epoxy resin solution dissolved at a ratio of g / ml was mixed by changing the volume mixing ratio, and a polycarbonate (PC) injection molded substrate with a diameter of 120 mm (thickness 1.2 mm, with simple spiral groove, by spin coating). Track pitch = 1.6 μm, half-width 0.4-0.6 μm, groove depth 600-800 Å) approx. 600-1200
It was applied to a thickness of Å to form a recording film.

The volume mixing ratio of the dye solution and the epoxy resin solution is 10% when the volume mixing ratio of the epoxy resin is 2%.
It was set to 0% and 30%, and as a comparison, a case where no epoxy resin solution was contained (epoxy resin volume mixing ratio 0%) was added.

[0026]

[Chemical 2] Next, on the recording film formed on the substrate as described above,
1000 Å thick light reflecting film made of Au film and thickness 3
A protective film made of a UV curable resin film having a thickness of μm was sequentially laminated from the substrate side to prepare an optical recording medium having a so-called reflective film having a light reflective film and a protective film, which was used as a sample material. Recording / reproduction test For each optical recording medium obtained as described above, a pickup having a wavelength of 784 nm and a lens numerical aperture (NA) of 0.5 was used, and a recording / reproduction linear velocity of 1 was set at a position of a radius of 40 mm.
1.0 m / sec, laser output (recording power) at recording 1
Recording / reproduction was performed under the conditions of 0.0 mW (lens emission) and readout power of 0.5 mW during reproduction. The frequency at the time of recording was a single frequency of the input source 108 ns. The recording amplitude (RF amplitude) of each optical recording medium is shown in FIG.
The carrier levels are shown in FIG. 2, respectively.

As is clear from FIGS. 1 and 2, the optical recording medium of the present invention containing an epoxy resin in the recording layer has higher recording amplitude and carrier level. Environmental Acceleration Test Each optical recording medium that was subjected to the recording / reproduction test above was
The sample was left to stand in an environment of 90 ° C. and RH of 90% for 2000 hours to perform an environmental acceleration test to examine how the recording amplitude and the carrier level change. FIG. 3 shows the recording amplitude reduction rate of each optical recording medium, and FIG. 4 shows the transition of the carrier level.

As is apparent from FIGS. 3 and 4, the optical recording medium of the present invention containing the epoxy resin has a smaller reduction rate of the recording amplitude and a smaller reduction amount of the carrier level, and therefore less deterioration and environmental resistance. You can see that it is excellent.

[0029]

As described above, in the optical recording medium of the present invention, since the recording film of the optical recording medium contains the Si-phthalocyanine dye and the epoxy resin,
It is possible to record at low power, the recording amplitude is large,
High career level. Also, the environment resistance as an optical recording medium is high.

[Brief description of drawings]

FIG. 1 is a graph showing a relationship between a volume mixing ratio of an epoxy resin solution and a recording amplitude.

FIG. 2 is a graph showing a relationship between a volume mixing ratio of an epoxy resin solution and a carrier level.

FIG. 3 is a graph showing the relationship between the elapsed time and the reduction rate of the recording amplitude in the environmental acceleration test.

FIG. 4 is a graph showing the relationship between the elapsed time and the amount of decrease in carrier level in the environmental acceleration test.

 ─────────────────────────────────────────────────── --- Continuation of the front page (72) Inventor Satoru Tanaka 6-1-1 Fujimi, Tsurugashima City, Saitama Pioneer Co., Ltd. (72) Inventor Shuichi Yanagisawa 6-1-1 Fujimi, Tsurugashima City, Saitama Prefecture Pioneer Research Institute (72) Inventor Fumio Matsui 6-1-1 Fujimi, Tsurugashima City, Saitama Pioneer Research Institute

Claims (3)

[Claims] 1. An optical recording medium having a recording film containing a Si-phthalocyanine dye represented by the following chemical formula (1), wherein the recording film contains an epoxy resin. [Chemical 1] [However, in the formula (1), R is a hydrogen atom, carbon number 1
A linear alkyl group having _{2~21, SO 2 NH- (CH 2} ) 3
_{-N- (C 2 H 5) 2} , SO 2 NH- (CH 2) 3 -N
- (CH ₃₎ represents either ₂ or O- (CH _{2) 19} -OH. ] 2. The optical recording according to claim 1, wherein the recording film is formed by using a recording film material in which a dye solution containing a Si-phthalocyanine dye is mixed with an epoxy resin solution. Medium. 3. The optical recording medium according to claim 2, wherein the volume mixing ratio of the epoxy resin solution is 5 to 40%.