JPS60239950A - Optical information recording medium - Google Patents

Abstract

PURPOSE:To prevent deterioration of a dye for a long period of time as a result of intrusion of oxygen in air therein and to obtain an optical information recording medium having improved optical stability, long life and high reliability by sealing a non-oxidizing gas into the hermetic space between two sheets of the substrates formed with the dye films which are recording layers on the inside. CONSTITUTION:The dye films 2 consisting of (mero)cyanine dye, triallyl methane dye, etc. are formed on one sides of transparent substrates 1, 1 consisting of glass, plastic, etc. A non-oxidizing gas such as methane butane, CO2, ethylene, propylene or Ar is sealed into a hermetic space 4 in the stage of superposing such films 2, 2 to face each other and manufacturing an optical information recording disk having the space 4 via a spacer 3. The deterioration of the recording layers 2 which are the dye films as a result of photooxidation is thus prevented and the optical information recording medium having >=100 times higher durability than the conventional medium is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to an optical information recording medium having a gas-filled structure. More specifically, the present invention relates to an optical information recording medium used in a method of directly recording with a laser beam and reproducing information by changing reflected light.

[Prior art]

Until now, the present inventor has proposed various optical information recording media having organic dye thin films (for example, Japanese Patent Laid-Open No. 57-21263
No. 9, JP-A-58-105442, JP-A-58-11
(See No. 2790, etc.). Such dye thin films are easier to manufacture and have better recording properties than conventional metal thin films, but they do not absorb sunlight or playback laser light in the presence of oxygen in the air. There was a problem in that the dye in the recording layer discolored when exposed to light, resulting in a lack of long-term storage stability. Therefore, as a countermeasure to this problem, it has been proposed to use a sealing structure (so-called sandwich structure) in which dye thin films are arranged facing each other with a space in between. However, oxygen in the air enters the space through the bonded portion, resulting in the deterioration of the dye over the long term, and this is not necessarily a satisfactory measure.

〔the purpose〕

The present invention has been made in view of the above problems, and its purpose is to improve the light resistance stability of a dye film in an optical information recording medium having a light-reflecting and absorbing dye film.

〔composition〕

In order to achieve the above object, the present invention is to suppress photodeterioration of a dye due to oxygen by sealing a non-oxidizing gas in a sealed space of an optical information recording medium having a sealed structure. That is, the optical information recording medium of the present invention has a sealing structure in which the substrates each having a dye film on at least one of the two substrates are arranged facing each other with a space in between so that the dye film is on the inside. The device is characterized in that a non-oxidizing gas is sealed in the closed space thus formed.

Representative examples of non-oxidizing gases that can be used in the present invention include methane, ethane, n-propane, isopropane,
n-butane, isobutane, allene, acetylene, arylene, α-butylene, r-butylene, carbon dioxide, carbon oxide, dimethyl ether, ethylene, formaldehyde,
Ketene, aminomethane, propylene, methyl chloride, methyl fluoride, methyl nitride, methylphosphine, vinyl chloride, ammonia, antimonas hydride, argon, holon fluoride, holon iodide, krypton, nitrogen dioxide, -nitrogen oxide, Examples include phosphine, but other non-oxidizing gases may also be used without any restrictions as long as they do not adversely affect the dye in the dye film recording layer.

The configuration of the present invention will be explained in detail below with reference to the drawings.

FIG. 1 shows an example of the recording medium of the present invention, in which two transparent substrates 1, 1 are made of a transparent material such as glass or plastic. The thickness of each substrate is usually 1.2w8 degrees, but can be arbitrarily selected. The shape of the substrate is not limited to a circle, but may be a square, a rectangle, a triangle, a polygon, or other various shapes. In the case of a circular shape, it is preferable that the diameter is usually 10 to 35 degrees. However, the size of the substrate can be arbitrarily selected depending on the application. Further, the substrate may be formed with guide grooves or bits, or may be subjected to other treatments.

A dye film 2 is provided on one surface of each transparent substrate 1 as a recording layer. The recording layer is formed using organic dyes such as cyanine dyes, merocyanine dyes, triphenylmethane dyes, triallylmethane dyes, etc., alone or in combination, or in combination with other dyes.

The thickness of the recording layer is 200~2000X, preferably 600~
1oooX is appropriate. In addition, for the formation of the recording layer 5
- Other additives commonly known in this field may also be added, such as anti-aging agents, binders, stabilizers, etc. Note that a subbing layer such as a photocurable resin may be provided between the dye film 2, which is the recording layer, and the substrate 1.

Each of the transparent substrates 1 having a dye film 2 is arranged with a space 4 interposed between the two sides 3 and 6 so that each dye film 2 is on the inside. The substrates 1, 1 are joined to the spacers 3.3 by adhesive or other means to form a sealed structure. The space 4 is filled with a non-oxidizing gas as described above in the present invention, and this gas layer maintains balance with the external atmospheric pressure. Furthermore, a center hole 5 is provided in the center of each of the substrates 1, 1, which functions as a jig for fixing a disk onto a turntable of a drive device. The above-mentioned spacer 3 is a member for preventing the recording layers 29.2 from coming into contact with each other, and there are no particular restrictions on its material 6- or shape. Examples of materials include glass, plastic, metal, paper, ceramics, cloth, etc. Furthermore, the shape of the suzusa is not limited to ordinary shapes such as squares and rectangles, but may be irregular shapes such as polygons. Although the configuration shown in FIG. 1 is an example of a double-sided disk, the present invention can of course be applied to a single-sided disk having a recording layer on only one substrate.

FIG. 2 is a schematic diagram showing a method for recording and reproducing information on a recording medium according to the present invention. A condensing laser beam 7 is irradiated onto the recording layer 2 through the transparent substrate 1 using a condenser lens 6 . When irradiated with strong laser power, the recording layer 2 is thermally changed to form small holes and recording is performed. On the other hand, by irradiating with a weak laser power and detecting the level of reflected light, information is reproduced as the presence or absence of small holes on the recording layer.

〔Example〕

The following structural formula (I) [NK2O14 manufactured by Nippon Kanko Shiki Kenkyushin] or the following structural formula (■) [NK made by Nippon Kanko Shokuryoku Kenkyu Shin] was applied to an acrylic substrate (manufactured by Mitsubishi Rayon, Acrylai AR) with a thickness of 1.0 mm. A dichloroethane solution of a cyanine dye (2883) was spin-coded to form a recording layer with a thickness of 500×, thereby producing a recording medium.

Next, two of these recording media were placed facing each other and sealed using an acrylic sealant in a gas flow shown in the table below to assemble a recording medium having the structure shown in FIG. 1.

Next, each recording medium assembled as described above was irradiated with tungsten light of 54,000 lux, which corresponds to the cumulative light intensity over 10 years in room light, for 60 hours, and then the rate of decrease in optical density at a wavelength of 790 nm was evaluated and the results were evaluated. They are summarized in the table below.

Comparative example Air 7270 Example 1 Methane 00 〃 2 Ethane 00 '5m-Propane 00 ' 4 1so-Pronosign 100 1 5 N-Butane 00 ' 6 1so-Butane 100 9 Example 7 Alene 00 1 8 Acetylene 00 19 Arylene 00 1 10 α-Butylene 00 1 11 γ-Butylene 00 I 12 Carbon dioxide 00 #13 -Carbon oxide 00 114 Dimethyl ether 00 115 Ethylene 00 #16 Formaldehyde 00 117 Ketene 00 I i8 Aminomethane 00 119 Propylene 00 I 20 methyl chloride 00 121 Methyl fluoride 00 122 Methyl nitride 00 # 23 Methylphosphine 00 1 24 Vinyl chloride 00 I 25 Ammonia 00 # 26 . 7'Gf;, % f Decrease rate ←) = Although the present invention has been described with respect to the case where a dye is used in the recording layer, the present invention also describes the case where a dye is used in the information recording layer. It will be understood by those skilled in the art that the present invention can also be applied to optical information recording media used as an optical information recording medium.

〔effect〕

According to the present invention, the stability of the recording medium against light is improved by more than 100 times compared to the conventional technology, so that the reliability of the recording medium can be improved.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an example of the optical information recording medium of the present invention, and FIG. 2 is a schematic diagram showing a method for recording and reproducing information on the optical information recording medium. DESCRIPTION OF SYMBOLS 1... Transparent substrate, 2... Dye film recording layer, 6... Space, 4... Closed space, 5... Center hole, 6...
Condensing lens, 7... Laser condensing beam. Patent applicant Rico Co., Ltd. −

Claims (1)

[Claims] The substrates each having a dye film on at least one of the two substrates are arranged facing each other with a space in between so that the dye film is on the inside, and a sealing structure is formed in which a non-oxidizing film is placed in the sealed space thus formed. An optical information recording medium characterized by enclosing a sexual gas.