JPS60180885A - Information-recording medium - Google Patents

Abstract

PURPOSE:To provide the titled medium capable of easily accomplishing conditions for rapid cooling and slow cooling in crystalline-amorphous transition of an information-recording layer and giving a clear pattern, comprising an information-recording layer in which transmittance is varired through crystalline-amorphous transition and a film the thermal conductivity of which varies with temperature. CONSTITUTION:A crystalline-amorphous transition film (e.g., TeGeSn) 22 consisting of an inorganic material film the light transmittance of which is varied through phase transition of a crystal is provided as the information-recording layer on a base 1 formed of a glass or the like, and a thermal conductivity variable film (e.g., a PVC film) 23 the thermal conductivity of which varies with temperature and which has a positive temperature coefficient is provided thereon to obtain the objective recording medium. When the medium is irradiated with laser beams, the irradiated regions 25, 24 are brought into a state in which heat is easily transmitted, and are rapidly cooled after the irradiation. Then the region 24 becomes an amorphous region, while the unirradiated regions of the films 23, 22 remain in a state in which heat is hardly released. Accordingly, the regions 25, 24 are rapidly cooled to become amorphous, while the unirradiated part around the regions 25, 24 are slowly cooled to remain in the crystalline state, providing a clear information record pattern.

Description

Detailed Description of the Invention Technical Field The present invention relates to an information recording medium using a thin film of an inorganic material in which crystal phase transition occurs as an information recording layer @Prior art Conventionally, inorganic materials in which crystal phase transition occurs relatively easily Information recording media using materials have been proposed. Figure 1 shows a conventional information recording medium.9 In Figure A, an inorganic material layer 2 is deposited on a glass thick substrate 1 by vacuum deposition, In Figure B, this is shown as a polycrystalline layer (microcrystalline) by heat treatment.
2', the irradiation part 6 in FIG. C is made amorphous by laser irradiation (a strong laser beam is irradiated in a very short period of time). Crystallized parts have low light transmittance, while amorphous parts have high light transmittance, so the information written by the crystalline amorphous dislocations can be interpreted as a change in light reflection or transmission intensity. I can get my bladder out. However, in this conventional information recording medium, the clarity of the transition region of the crystal is not sufficient, and errors in the recorded pattern are likely to occur due to the unclearness, and the material (chemical species) of the information recording layer is limited to a narrow range. There was a drawback that

Purpose of the Invention The present invention is to enable the crystal-amorphous noble transition to occur more easily in the inorganic material layer of the information recording layer, and to expand the chemistry of inorganic materials that can be used in the information recording layer. Its purpose is to

Structure and operation of the invention In the present invention, an information recording layer whose transmittance changes due to a crystalline amorphous transition and a gland whose thermal conductivity changes depending on the temperature are provided to prevent the crystalline amorphous transition that is a crystalline phase transition. to occur easily.

An example will be shown below to specifically explain the structure and operation of the present invention. In FIG. 2A, a crystal-amorphous transition film (TmGaSn) 22 is provided as an information recording layer on a substrate 1 made of glass or plastic, and a heat conduction change J[23 is provided thereon. The crystal-amorphous transition film 22 is a TaGaSn layer (several 10
0 to 100 DA) by microcrystallizing it by heat treatment. The thermally conductive variable film 23 formed thereon is a film with low thermal conductivity, such as polyvinyl chloride (several 10
0~1000. ;) is used. Polyvinyl chloride has a property that its thermal conductivity changes with temperature as shown in FIG. In other words, as shown in Figure 4, the thermal conductivity of polyvinyl chloride increases as the temperature rises, and increases from 0.1 to g
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Thermal energy is applied to the information recording medium configured in this way using a high-power laser beam.

This high power laser beam for writing is, for example, 10
Set to 0mF and irradiate for a very short time. As a result, as shown in FIG. 2B, the area 25 of the polyvinyl chloride film 26 in the laser beam irradiation area has a high thermal conductivity, so that the area 25 and the crystal-amorphous transition film 22 are exposed to the laser beam. The irradiation area 24 becomes in a state where heat is easily conducted, and is rapidly cooled after irradiation. The area 2 thus irradiated with the laser beam
5.24 is rapidly cooled, and in this case, a transition from crystal to amorphous occurs in the crystal-amorphous transition film 22, and the region 24 becomes an amorphous region. In this case, the portion other than the region 25 of the polyvinyl chloride irradiated with the laser beam, that is, the unirradiated variable thermal conductivity film 23 has low thermal conductivity, and the unirradiated variable thermal conductive film 23 and the crystalline amorphous film 23 have low thermal conductivity. The transition film 220 portion serves as a means for heat to escape. Therefore, area 2 of the irradiation part
5.24 In contrast to rapid cooling, an amorphous transition occurs,
The unirradiated portion near the bottom is slowly cooled and is maintained in a crystalline state, thus providing a clear information recording pattern.

Next, the information recording pattern obtained in this way is irradiated with a low-power laser beam to induce a crystal-amorphous transition.
As a result of the change in thermal conductivity occurring in the opposite direction to that in the above-mentioned 1-inclusive case, it can be easily eliminated. This low power laser beam is, for example, 10 mW, and is irradiated for a longer time than in the case of rock encroachment.

Another embodiment of the invention is shown in FIG. In this example, in addition to providing a thermally conductive variable film 56 above the crystalline amorphous transition film 32 that is the information recording layer, another thermally conductive variable film 3 is also provided on the substrate 1 side.
4 is provided. The upper heat conduction change film 56 is formed to a thickness of several hundred to 100 mm, and the lower heat conduction change film 56
The thickness of 4 can be formed without any particular restrictions. The information recording layer is formed to an extent of 100 to 100,000 crystal/amorphous transition/transfer. In this example, since the thermal conductivity of the region 65.degree. 37 of the thermally conductive variable film in the laser beam irradiation part increases, the heat of the region 55.56.degree. 57 is rapidly lost in both the vertical direction and is rapidly cooled. The region 66 undergoes an amorphous transition, and a clear information recording pattern is obtained.

The present invention has been explained above using examples.
The conditions for the crystalline amorphous transition film and the thermal conductivity change film will be explained below.

(:) Crystalline amorphous transition film Many crystalline amorphous transition materials are known, and the present invention can widely use these materials. For example, in addition to TaGm5 in the previous example, Ta-Ga, Ta-51, Aa-5
a% alloy, Ta, Sm age simple substance, TaO2 group oxide, etc.

(10) Transparency is required for the material used on the upper surface of the thermally conductive variable film, that is, on the laser beam incident side, but transparency is not required on the lower surface. Various materials with large and positive temperature coefficients are used.

Effects of the Invention According to the present invention, by providing the variable thermal conductivity film as described above, it is possible to easily realize the rapid cooling and slow cooling conditions for the crystal-amorphous transition of the information recording layer, resulting in clear information recording. You can get the pattern. Furthermore, since highly rapid cooling conditions can be achieved, there is an advantage that chemical capture of the material of the information recording layer is increased compared to the conventional method.

[Brief explanation of drawings]

1A to 1C are process diagrams showing the information recording pattern form h4 using a sub-4 information recording medium, and FIG. 2 74. B is a process diagram showing the formation of an information recording pattern using an information recording medium according to an embodiment of the present invention, FIG. 6 is a diagram showing an information recording medium according to another embodiment of the present invention, and FIG. The figure which shows the temperature characteristic of the thermal conductivity of vinyl (softening point 150-170 degreeC, melt|dissolved at 190 degreeC). Main symbols 1... Substrate, 2... Inorganic material layer, 6... Irradiation part,
22...Crystal-amorphous transition film (information recording layer), 26...
・Thermal conductivity change membrane (polyvinyl chloride membrane), 24...(
) area of the crystalline amorphous transition film in the irradiated area, 25... area (of the thermally conductive variable film in the irradiated area), 32... crystalline amorphous transition film (information recording layer), 66... ( Lower) thermally conductive variable membrane, 64... (upper) thermally conductive variable membrane Patent applicant Fujitsu Limited Representative Patent Attorney Tama Mushi Artificial Department (1 other person) Fig. 1 Fig. 2 IP43 Fig. 4 Temperature (0c)

Claims (3)

[Claims] (1) An information recording layer made of an inorganic material thin film whose light transmittance changes due to crystal phase transition, and a thermal conductivity change film whose thermal conductivity changes with temperature and whose temperature coefficient is positive. An information recording medium characterized in that: are laminated on a substrate. (2) The information recording medium according to claim 1, wherein the thermally conductive variable film is provided on the information recording layer. (3) Information recording medium 0 according to claim 1, characterized in that the thermally conductive variable film is provided on the information recording layer and between the information recording layer and the substrate.