JPH0652578A - Optical information recording medium - Google Patents

Abstract

PURPOSE:To shorten a time of initial crystallizing or entire erasing a recording film of an optical information recording medium and to eliminate a fear of a deformation of a board, etc. CONSTITUTION:An optical information recording medium 10 is formed by sequentially forming a lower layer protective film 2 made of ZnS-SiO2, a recording film 3 made of GeTe-Sb2Te3, an upper layer protective film 4 made of ZnS-SiO2, a reflecting film 5 made of Al, an insulating film 6 made of Al-N and a heater film 7 made of Ni-Cr on a board 1 made of polycarbonate. The medium 10 formed of this configuration can be instantaneously heated at the film 3 at its crystallizing temperature or higher by energizing the film 7, and instantaneously crystallized. That is, initial crystallizing or entire erasing of the film 3 can be completed in an extremely short time as compared with prior art. Thus, the medium has mass productivity and is improved in initial quality and easy availability on the way.

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 capable of recording information using light.

[0002]

2. Description of the Related Art Conventionally, there has been known a phase change type optical information recording medium (optical disk) which makes use of a change in reflectance caused by a phase transition between amorphous and crystalline. In this optical information recording medium, when information writing is achieved by amorphization, the entire recording film must be in a crystalline state in advance. Here, at least a part of the recording film of the optical information recording medium immediately after being formed by the vacuum evaporation method or the sputtering method is in an amorphous state or in a metastable crystalline state. Therefore, it is necessary to completely crystallize the entire recording film (initial crystallization) before writing information on this. Further, in order to completely erase the information once recorded on the recording film of the optical information recording medium, it is necessary to completely crystallize the entire recording film.

Here, the one disclosed in Japanese Unexamined Patent Publication No. 62-20153, "Initial Crystallizing Method of Optical Disc" is known. Here, a method of heating the entire optical information recording medium by using an oven or the like to crystallize the recording film or a high power laser such as an Ar laser is used to irradiate and heat the recording film of the optical information recording medium. , A method of crystallizing the recording film is described.

[0004]

According to the former means,
The temperature for crystallizing the entire recording film of the optical information recording medium is also applied to the substrate, and the substrate made of a material that cannot withstand high temperature may be deformed. on the other hand,
When heating at a low temperature while avoiding this deformation, a huge amount of time was required to completely crystallize the entire recording film.
Further, even in the latter means, there is a problem that an enormous amount of time is required to crystallize all the tracks in the recording film of the optical information recording medium.

The present invention has been made to solve the above problems, and an object of the present invention is to shorten the time for initial crystallization of the recording film of the optical information recording medium or for complete erasing. It is to eliminate the risk of deformation of the substrate.

[0006]

The structure of the invention for solving the above-mentioned problems is to heat the recording film in an optical information recording medium in which a lower protective film, a recording film and an upper protective film are sequentially formed on a substrate. It is characterized in that at least one heater film is provided to crystallize until the first recordable state (initial crystallization) or crystallize until the recorded information is completely erased.

[0007]

According to the above means, by energizing the heater film in the optical information recording medium, the recording film can be instantly heated to the crystallization temperature or higher, and the recording film can be instantly crystallized. be able to. That is, the initial crystallization or full erasure of the recording film of the optical information recording medium can be completed in an extremely short time as compared with the conventional case. As a result, the optical information recording medium can be mass-produced, and the initial quality and the ease of use in the middle can be improved.

[0008]

EXAMPLES The present invention will be described below based on specific examples. FIG. 1 is a schematic diagram showing a cross-sectional structure of an optical information recording medium according to the present invention. The optical information recording medium 10 is formed by sequentially laminating the following films on a substrate 1 made of, for example, disk-shaped transparent glass or plastic. First, on the substrate 1 made of polycarbonate, ZnS-Si
The lower protective film 2 made of O _{2 was formed} to a thickness of 250 nm. Next, a recording film 3 made of GeTe—Sb ₂ Te ₃ was formed on the lower protective film 2 to a thickness of 80 nm. An upper protective film 4 made of ZnS—SiO ₂ was formed thereon with a thickness of 35 nm. Further, a reflective film 5 made of Al was formed on the upper protective film 4 to a thickness of 40 nm. The insulating film 6 made of Al-N is formed on the reflective film 5.
Was deposited to a thickness of 30 nm. Finally, Ni-C is formed on the insulating film 6.
A heater film 7 made of r was formed to a thickness of 30 nm. Here, each of the lower protective film 2, the recording film 3, the upper protective film 4, the reflective film 5 and the insulating film 6 is formed by sputtering,
The heater film 7 was formed by vapor deposition. The method for forming each of these films is not limited to the sputtering method or the vapor deposition method, and other suitable methods may be used.

FIG. 2 is a conceptual diagram showing an initial crystallization or full erasing process using the heater film 7 of the optical information recording medium 10 having the above-mentioned structure. At the time of initializing or erasing the entire surface of the optical information recording medium 10, electrodes E _{1 and} E ₂ are brought into contact with both ends of the outer periphery of the heater film 7 and are energized by using a direct current or an alternating current power source. This energization causes the heater film 7 to generate heat. During this energization, the heater film 7 is heated so that the entire surface of the recording film 3 is quickly heated to 200 to 600 ° C., which is higher than its crystallization temperature.
The voltage applied to was adjusted. The energizing time at this time is 1/1
It was an extremely short time (instantaneous) of about 00 seconds. That is, the optical information recording medium 10 is suitable for mass production because the time required for the initial crystallization of the recording film 3 or the entire surface erasing step is very short, and the substrate 1 is not likely to be deformed.

The present invention is not limited to the above embodiment, but various modifications such as the following are possible. (1) If a metal having a high reflectance is used as the material of the heater film, it can also be used as the reflective film. In this case, the insulating film on the reflective film can be eliminated. (2) If the material of the heater film is a transparent conductive thin film such as ITO (Indium Tin Oxide), it is not necessary to set the film forming position to the uppermost layer as in the above embodiment. . That is, the heater film can be formed at any position between the substrate and the reflective film. In this case, an insulating film may be provided on both sides or one side of the heater film as needed. (3) Since the electrodes are connected to the heater film, each film may be processed into a required shape. (4) A plurality of heater films may be provided if necessary. (5) The heater film and the insulating film may be processed into appropriate shapes as long as the heat generation necessary for crystallizing the recording film is obtained. (6) The material and film thickness of each film may be any other appropriate material and film thickness. For example, as the lower protective film and the upper protective film, the above ZnS-
Can be used SiN, AlN, and SiO _2, TiO ₂ refractory transparent dielectric material such as a non-SiO _2. As the recording film, the rewritable phase change recording material such as GeSbTe system or InSbTe system described above can be used. As the reflective film, Au or the like can be used in addition to Al described above. (7) Either or both of another protective film and a protective substrate may be set on the heater film which is the uppermost layer in the above embodiment,
Instead of the protective substrate, an optical information recording medium having the same structure may be attached. (8) The temperature obtained by the heat generation of the heater film may be controlled to an appropriate temperature depending on the material of the recording film, the protective film, etc. and the structure of the optical information recording medium.

[Brief description of drawings]

FIG. 1 is a schematic view showing a cross-sectional structure of an optical information recording medium according to a specific example of the present invention.

FIG. 2 is a conceptual diagram showing an initialization or full erasing process with a heater film of the optical information recording medium in the example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Substrate 2 ... Lower protective film 3 ... Recording film 4 ... Upper protective film 5 ... Reflective film 6 ... Insulating film 7 ... Heater film 10 ... Optical information recording medium

Claims (1)

[Claims] 1. An optical information recording medium in which a lower protective film, a recording film, and an upper protective film are sequentially formed on a substrate, and the recording film is heated to crystallize until the first recordable state (initial crystallinity). Or an optical information recording medium having at least one heater film for crystallizing until the recorded information is completely erased.