JPH05301459A - Optical data recording medium - Google Patents

Abstract

PURPOSE:To enhance the reliability of an optical data recording medium wherein an org. dye layer, a reflecting layer and a protective layer are formed on a substrate and a printing layer is further formed on the protective layer. CONSTITUTION:An optical data recording medium having high reliability consists of a light pervious disc-shape substrate 1, the recording layer 2 composed of a cyanine type photosensitive dye layer formed on the disc-shape substrate 1, the reflecting film 3 composed of a gold membrane covering the recording layer 2, the protective film 4 covering the reflecting film 3, the printing layer 5 partially applied to the protective film 4 and the protective film 6 covering the protective film 4 having the printing layer 5 formed thereon, and the reflecting film is prevented from rising or separating from the underlying layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical information recording medium, and more particularly to a highly reliable write-once type optical information recording medium.

[0002]

2. Description of the Related Art A write-once type optical information recording medium has a recording layer formed of an organic dye such as a cyanine dye, a phthalocyanine dye, or a naphthoquinone dye formed on a light-transmissive disk-shaped substrate made of a polycarbonate resin or the like. It is known that information is recorded by irradiating a recording layer with a laser beam and causing a change in reflectance or transmittance due to thermal deformation, hole formation or the like in the irradiated portion.

Such organic dyes are notably used as a recording material, and have the advantage that a film can be easily formed by a spin coating method. Since the cost for forming a film is low, they are widely used. Has been. However, the reflectance of the recording layer composed of only organic dye is at most 30-40%.
And the reproduction sensitivity is not sufficient. Therefore, in the write-once type optical information recording medium compatible with the recently proposed compact disc, a metal reflective film such as aluminum or gold is laminated on the organic dye film formed on the substrate to obtain a high reflectance. I'm trying to get it. Further, a protective film such as an ultraviolet curable resin film is provided on the metal reflective film, and a print layer on which the matter related to the content of the recording medium is displayed is provided on the protective film.

[0004]

However, in general, a metal reflection film of aluminum, gold or the like has a drawback that the adhesion to the organic dye film is weak. When a print layer is formed on the protective film on the write-once type optical information recording medium as in the case of the compact disc, the hygroscopic property and the water permeability of the protective film are formed between the part provided with the print layer and the other part. Differences in sex etc. occur,
As a result, stress is generated inside the protective film. Therefore, peeling occurs in the reflection film in the portion corresponding to the protective film provided with the printing layer. When the recording medium in such a state is reproduced, noise increases, and there is a serious problem that the reliability of the recording medium is impaired.

The present invention has been made in view of the above, and an object thereof is to provide an optical information recording medium having improved reliability.

[0006]

An optical information recording medium of the present invention comprises a light-transmissive substrate, a recording layer containing an organic dye formed on the main surface of the substrate, and a reflective film covering the recording layer. A first protective film covering the reflective film, a printed layer formed on the first protective film, and a second protective film formed on the first protective film to cover the printed layer. It is a thing.

[0007]

In the optical information recording medium of the present invention, by providing the second protective film for covering the print layer, the water permeability and the like in the part where the print layer is present and in the other part are made substantially equal, whereby The internal stress of the protective film of No. 1 is relaxed, partial peeling of the metal reflective layer is suppressed, and reliability is improved.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the optical information recording medium of the present invention will be described with reference to FIG. In FIG. 1, reference numeral 1 is a light-transmissive circular disk-shaped substrate, 2 is a recording layer formed on the substrate 1, 3 is a reflective film covering the recording layer 2, and 4 is a first protective film for protecting the reflective film 3. Of the protective film 5 is a printed layer formed on the protective film 4,
Reference numeral 6 is a second protective film formed on the protective film 4 so as to cover the printed layer 5. The substrate 1 is made of, for example, a transparent synthetic resin such as methacrylic resin, polycarbonate resin or the like, polyolefin resin or the like, and is provided with a spiral guide groove having a depth of 60 to 250 nm. The recording layer 2 is composed of an organic dye, for example, a cyanine dye, a polymethylene dye, a phthalocyan dye, etc., but may contain two or more kinds of organic dyes, and further a resin or the like. The recording layer 2 made of an organic dye film is formed to have a thickness of about 60 to 250 nm.

The reflective film 3 is preferably a metal film, for example,
It is made of gold, silver, aluminum, or an alloy containing them, and these metals are deposited by a vapor deposition method, a sputtering method, or the like.
It is formed to a film thickness of nm or more. It is preferable to use gold in order to obtain a high reflectance of 70% or more so as to maintain compatibility with the compact disc. The protective film 4 is preferably formed of a resin having low water permeability. Protective film 4
Is formed by applying an ultraviolet curable resin by spin coating and irradiating it with ultraviolet light to cure it.

The printing layer 5 has a thickness of about 10 μm and is made of, for example, an ultraviolet resin type resin mixed with an oily printing ink, and displays items related to the recorded contents of the optical information recording medium. An ultraviolet curable resin mixed with ink is screen-printed on the protective film 4 and irradiated with ultraviolet rays to be cured to form the resin. The protective film 6 has a thickness of about 10 to 20 μm and is low in water permeability and hygroscopicity, or the printing layer 5
It is desirable that the resin has properties such as water permeability and hygroscopicity equivalent to those of the ultraviolet curable resin used for. The protective film 6 is formed by applying an ultraviolet curable resin so as to cover the protective film 4 and the printed layer 5 by a screen printing method or the like, and irradiating with ultraviolet rays to cure the resin.

Further, the optical information recording medium of the present invention will be described in detail. A guide groove is formed in a circular disk-shaped substrate 1 having a diameter of 12 cm and a thickness of 1.5 mm, which is made of polycarbonate resin. The cyanine-based photosensitive dye layer to be the recording layer 2 is formed by coating the substrate 1 on which the guide groove is formed with a thickness of 100 nm by a spin coating method. Subsequently, a reflection film 3 made of a gold thin film having a thickness of 150 nm is formed thereon by a DC magnetron sputtering method, and then an ultraviolet curable resin [DIC SD-301 manufactured by Dainippon Ink and Chemicals, Inc.] is spin-coated. Apply
Ultraviolet rays are radiated to form a first protective film 4 having a thickness of 10 μm. Furthermore, a UV curable ink manufactured by Dainippon Ink and Chemicals, Inc., such as DICURE SSD
After 140 (trade name) is screen-printed to form a printing layer 5 having a thickness of 10 μm, a second layer having a thickness of 10 to 20 μm is screen-printed by using only an ultraviolet curable resin component which is a thick material of the ink. The protective layer 6 is applied to form.

Next, the optical recording medium A of the present invention and the conventional optical information recording medium B on which the second protective film is not formed.
The results of the accelerated test of No. 1 will be described below. FIG. 2 shows that the humidity is 90% for the optical information recording media A and B.
The result of measuring the change of the reproduction signal when the acceleration test is performed for 96 hours in the environment of RH and temperature of 60 ° C. is shown. 2A and 2B, the horizontal axis represents time and the vertical axis represents amplitude voltage.

FIG. 2A shows a reproduced signal waveform of the optical information recording medium A, and FIG. 2B shows a reproduced signal waveform of the optical information recording medium B. As is clear from FIGS. 2 (a) and 2 (b),
In FIG. 2A, the change in the amplitude of the signal waveform is small, whereas in FIG. 2B, a large number of waveforms with large amplitude are generated. The large fluctuation of the amplitude indicates that the recording medium has a defect (partial peeling of the reflective film or film floating). In fact, when the optical information recording medium B is observed, it can be seen that peeling has occurred in the reflective film corresponding to the print layer. On the other hand, in the optical information recording medium A of the present invention, the peeling of the reflective film did not occur, the change with time was small, and the reliability was improved.

Of course, in the optical information recording medium of the present invention, the material, dimensions, and shape of the substrate and the like are not limited to those of the embodiment, but various known materials or equivalent materials can be used. If so, it is clear that it can be used in the present invention.

[0015]

The optical information recording medium of the present invention is provided with the second protective film which covers the printed layer formed on the first protective film, so that the first protective film has water permeability, water absorption and the like. Since the occurrence of a difference in stress and the occurrence of stress are suppressed, peeling of the reflective film and film floating can be prevented, and the reliability can be improved, which is extremely effective.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of an optical information recording medium according to the present invention.

FIG. 2A is a diagram showing a reproduced signal waveform of an optical information recording medium of the present invention after an acceleration test, and FIG. 2B is a reproduced signal waveform of a conventional optical information recording medium after an acceleration test. It is a figure which shows a waveform.

[Explanation of symbols]

 1 Disc-shaped substrate 2 Recording layer 3 Reflective film 4, 6 Protective film 5 Printing layer

Continuation of front page (51) Int.Cl. ⁵ Identification number Internal reference number FI Technical indication location G11B 7/24 571 A 7215-5D (72) Inventor Atsushi Kondo 2680 Nishihanawa, Tatomi Town, Yamanashi Prefecture Pioneer Video Incorporated (72) Inventor Shunsuke Hara 2680 Nishi Hanawa, Tatomi-cho, Nakakoma-gun Yamanashi Pioneer Video Incorporated (72) Inventor Kenji Suzuki 2680 Nishi Hanawa, Tatomi-cho, Nakanima-gun Yamanashi Pioneer Video Co., Ltd.

Claims (1)

[Claims] 1. A light-transmissive substrate, a recording layer containing an organic dye formed on the main surface of the substrate, a reflective film covering the recording layer, a first protective film covering the reflective film, and 1. An optical information recording medium comprising a printed layer formed on the first protective film and a second protective film formed on the second protective film so as to cover the printed layer.