JPS63268142A - Optical recording medium - Google Patents

Abstract

PURPOSE:To attain excellent light resistance and oxidation resistance by forming a sensitivity enhanced layer and a thin metallic film layer on a substrate in this order, and forming the former layer with a material that deforms with heat energy of a write beam. CONSTITUTION:On the substrate 2, the sensitivity enhanced layer 3 is formed with gelatine, caseine, etc., on the top of which the thin metallic film layer 4 of Cr, Ni, etc., is formed. That is, by combining the layer 4 which is of low writability and the layer 3 which easily deforms with heat, the function is separately imposed so that the absorption of light is achieved by the thin metallic film layer 4 while the thermal-deforming is achieved by the sensitivity enhanced layer 3. When a write beam 6 is radiated on this recording medium 1, the sensitivity enhanced layer 3 deforms due to heat and a part surrounding a spot elevates, and thus information pit is generated. Hence, the metal layer does not need to deform with the heat, hence it does not need to be Te or else that is of low resistance to oxidation. Therefore, the oxidation resistance can be improved. Also, since the sensitivity enhanced layer 3 is convered by the metal layer 4, light resistance is improved.

Description

Detailed Description of the Invention (a) Purpose of the Invention [Field of Industrial Application] This invention relates to optical recording media, particularly writable (DRAW) media.
type) related to optical recording media.

Optical recording media are used to optically record audio, images, and other signals, and are used in disks and cards. In particular, in recent years, cards on which various types of information are recorded have become popular, such as ID cards, cash cards, and bank cards.

[Prior Art] Disks using optical recording members are widely used as recording members for digital signals such as audio and images. In addition, it is necessary to record various information such as personal data and issuing company data on the card, and at the initial stage, such information is recorded in visible characters and symbols. In the later stages, electrical signals using magnetism are used to record information, but it is necessary to prevent tampering and cope with the increasing number of information sources.

To this end, optical recording cards using laser technology have recently been developed. This optical recording card is equipped with an optical recording medium having an optical reflective surface. As shown in FIG. 4, the optical recording medium is an optical recording medium 102 in which a recording film 102 of an organic material containing a dye is formed on a substrate 101.
As shown in FIG. 5, a single-layer metal film 103 made of a metal with good writability and high light absorption rate, such as 7re, is formed on a substrate 101. As shown in the formed optical recording medium 100b, and as shown in FIG. There is an optical recording medium 100C in which an optical recording film 106 is formed of metal.

[Problems to be Solved by the Invention] However, in the case of the optical recording medium 100a, the writing light 110
Concave portions 111 are formed in the recording film 102 due to thermal deformation due to the irradiation.
This recess 111 is used as an information bit 111a, but since the dye itself is a sensitizing material for the recording film 102, it also reacts to natural light, and therefore has poor light resistance. low.

Next, in the case of the optical recording medium 100b, the metal film 103 is perforated by the writing light 110, and this hole 112 is used as the information bit 112a.
Metals such as Te that have good writability and high light absorption and light reflectance have low oxidation resistance, and oxidation deteriorates the absorption and reflectance of writing light, resulting in loss of writability. There is.

Next, in the case of the optical recording medium 100C, the optical recording film 106 is perforated by the writing light 110 and the perforations 113 are used as information bits 113a. There is a problem that the conditions for controlling the film thickness are strict and manufacturing is not easy.

For these reasons, it is desired to develop an optical recording medium that has excellent light resistance and oxidation resistance and is easy to manufacture.

The present invention was made in view of the above circumstances, and it is an object of the present invention to provide an optical recording medium that has excellent light resistance and oxidation resistance and is easy to manufacture.

(B) Structure of the Invention [Means for Solving the Problem] Corresponding to this object, an optical recording medium includes a substrate, a sensitizing layer formed on a surface of the substrate on the writing light incident side, and a sensitizing layer formed on the surface of the substrate on the writing light incident side. The sensitizing layer is made of a material that is thermally deformed by the thermal energy of the writing light.

Hereinafter, details of the present invention will be explained with reference to the drawings showing one embodiment.

In FIG. 1, 1 is an optical recording medium. Optical recording medium 1
The device has a substrate 2, a sensitizing layer 3 on the surface of the substrate 2 on the 1-include light incident side, and a metal thin film 4 laminated on the surface of the sensitizing layer 3.

As the substrate 2, for example, a polyester film having a thickness of 0.1 am is used.

When the intensifying port 3 is irradiated with writing light, a metal thin film It! 1
A material that easily undergoes permanent deformation such as contraction or expansion by the heat generated in step 4 is preferable, and can be composed of pyratin, casein, PVA, etc. Gelatin is particularly suitable. Using a black gelatin film in which carbon black is dispersed, or a black gelatin film in which silver particles are dispersed through photographic exposure and development, is effective because the light energy that cannot be absorbed by the metal thin film layer 4 can also be used. It is true. In addition, substrate 2 and sensitization ll! A reflective film made of a thin film of Aρ or the like may be provided between the A.rho. In this case, it is possible to improve the reflectance.

As the metal thin film layer 4, Cr, Ni, Co, Au, etc. are used. The thickness of the metal thin film layer 4 is determined by the reflectance and absorption factor that should be selected, but in particular, in the case of Cr, it is 50A ~
Approximately 5008 is suitable.

It is not preferable to use unstable materials that are easily oxidized, such as Te.

[Function] The function of the optical recording medium configured as described above is as follows.

In the case of writing, when the writing light 6 is irradiated from the surface side of the gold B thin film layer 4 as shown in FIG. 2, photothermal energy is transmitted to the surface layer of the sensitizing layer 3 through the metal thin film layer 4.
The surface layer of the sensitizing layer 3 undergoes thermal deformation. The thermal deformation state is
According to experiments, when the writing light 6 is a spot light, the central part is depressed and the peripheral part is raised like a bank. This sensitized layer 3
As the metal thin film layer 4 is deformed, the metal thin film layer 4 deposited on the surface of the sensitizing layer 3 also becomes depressed, and this depression constitutes the information bit 7. This completes the information writing.

Next, in the case of reading, the information bit 7 is detected by the reading light.

(c) Effects of the invention The optical recording medium of the invention combines a metal thin film layer with high stability, that is, low writability (low reaction) and a sensitizing layer that is easily thermally deformed, and a metal thin FI layer. 4 is utilized for the light absorption and reflection layer, and the thermal deformation is shared by the sensitizing layer. As a result, the metal thin film layer does not require thermal deformation, so Te
There is no need to use materials with low oxidation resistance such as
, Ni, etc., the oxidation resistance can be improved.

On the other hand, by covering the sensitized layer, which has low light resistance, with a metal thin film layer, it becomes possible to investigate thermal deformation to the fullest extent. In this manner, according to the present invention, it is possible to obtain an optical recording medium that has excellent light resistance and oxidation resistance and is easy to manufacture.

[Experimental Example] As shown in FIG. 3, a sensitized layer 3 was formed on a glass substrate 2 using black gelatin containing silver particles obtained by exposure and development, and on top of that a sensitized layer 3 made of or made of glass with a thickness of about 10 OA was formed. A metal thin film layer 4 was formed to obtain an optical recording medium 1 for a sample.

When this optical recording medium 1 was scanned by irradiating a laser with an LD output of 1.0 to 8.2 mW and a wavelength of λ-830 nm, it was found that at an LD output of 1.0 to 1.5 mW, there were no readable streaks on the surface of the sample. Although not formed, L'D output 1.5
At mW to 8.2 mW, readable concave groove-like streaks were formed, making it clear that the film functioned as an optical recording medium.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional explanatory diagram of the optical recording medium of the present invention, FIG. 2 is a cross-sectional explanatory diagram showing the state of the optical recording medium of the present invention during writing, and FIG. 3 is a sample of the optical recording medium used in the experiment. FIG. 4 is a cross-sectional explanatory diagram showing a conventional optical recording medium, FIG. 5 is a cross-sectional explanatory diagram showing another conventional optical recording medium,
and FIG. 6 are cross-sectional explanatory views showing still another conventional optical recording medium. DESCRIPTION OF SYMBOLS 1... Optical recording medium 2... Substrate 3... Sensitizing layer 4... Metal thin film layer 5... Reflective layer 6...
Writing Light 7...Information Bit Patent Applicant Kyodo Printing Co., Ltd. Patent Attorney Osamu Kawai Figure 1 Figure 3 ■

Claims (1)

[Claims] It comprises a substrate, a sensitizing layer formed on the surface of the substrate on the writing light incident side, and a metal thin film layer formed on the sensitizing layer, and the sensitizing layer is heated by the thermal energy of the writing light. An optical recording medium characterized in that it is made of a material that causes deformation.