JPS62137740A - Additional writing type optical information recording disk and its production - Google Patents

Abstract

PURPOSE:To shorten the time for opening pits by incorporating a high-polymer material having the melting temp. lower than the melting temp. of a recording film into the recording film so that the melting and evaporating of the recording film are accelerated by the pressure of the gas and the effect of reaction heat generated during melting of the high-polymer material. CONSTITUTION:A rugged pattern 2 is formed on one side of a disk substrate 1. The recording film 3 is formed by a mixture composed of a recording mate rial for heat mode and the low melting high-polymer material. 1 or >=2 Elements selected from S, Se, Te, Bi, Sn, Pb, In, Zn, Mg, Au, Ce, Ca, Sb, Rh, Mn, and Al are preferably used in terms of sensitivity, S/N ratio and low toxicity as the recording material for heat mode out of two kinds of the materials constitut ing the recording film 3. 1 or >=2 High-polymer materials selected from a poly carbonate, PP, PE, nitrocellulose, guanine or the modified matter thereof are particularly preferably used for the low melting high-polymer material.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a write-once optical information recording disc.

More specifically, the present invention relates to a write-once optical information recording disc in which a pit array corresponding to an information signal is created in a recording film by irradiating a high-energy density light beam such as a laser beam.

[Conventional technology]

Conventionally, as shown in FIG. 3, there has been known a write-once optical information recording disk in which a recording film 13 made of a heat mode recording material is formed on a concavo-convex pattern forming surface 12 of a disk substrate 11.

This optical information recording disc is based on the above-mentioned disc t! 1E
By irradiating a high energy density light beam such as a laser beam modulated by an information signal from the surface opposite to the uneven pattern forming surface 12 of 11, the recording film 13 is locally heated, melted, and evaporated. , a row of pits (through holes) arranged in accordance with the information signal is opened.

When reading information from an optical information recording disk on which information has been recorded as described above, a reproducing light beam is irradiated along the pre-groups transferred to the disk substrate 11 to open pits. This is done by detecting the difference in reflected light intensity between the open area and the unopened area.

Such optical information recording disks: 1) have an information recording density several tens of times higher than magnetic recording media; and 2) record and reproduce information without contact, so despite their high density recording, they are not fixed disks. There is no need to change the disk, making it easy to replace the disk.

(2) Since it has a structure in which information is recorded by opening holes (pits) in the recording film, it has the characteristic of being able to be stored for a long period of time, so it is attracting particular attention as a computer memory.

[Problem that the invention seeks to solve]

As mentioned above, the lightning information recording disk is.

By concentrating a high energy density light beam on the recording ff5!13, it is locally heated and melted, and the recording g! of the light beam irradiated area is recorded. 13 is evaporated to open a row of pits (through holes) arranged in accordance with the information signal. Therefore, the recording speed of this information recording disk is determined by the correlation between the sensitivity of the recording film 13, which is determined by the melting temperature, thermal conductivity, light absorption rate, etc. of the recording material, and the energy density and irradiation time of the light beam.

However, at present, not only is it not possible to obtain a recording material with a sufficiently high recording sensitivity for practical use.

Because high-power optical beam generators (e.g., semiconductor lasers) are very expensive, practical disk drives require
Only a light beam generator with relatively low output (approximately 8 mW or less) can be installed, and information can only be recorded by slowing down the rotation speed of the optical information recording disk and lengthening the irradiation time of the light beam. Can not do it.

For this reason, conventionally known write-once optical information recording disks have the problem that, compared to magnetic disks, the access time is several times as long as the IO, and the information transfer speed is about twice as long.

[Means for solving problems]

By the way, the mechanism by which the pits are opened has not been clearly elucidated, but it is thought to be as follows: The portion of the recording film irradiated with the light beam is heated and melted, and then melted. Part of the recording material, especially the central part corresponding to the center of the beam spot with high energy density, evaporates, the surface tension of the melted recording material is broken, and the remaining melted recording material is drawn around the beam spot, forming pits. It will be established.

Therefore, if a polymer substance with a melting temperature lower than that of the recording film is mixed inside the recording film, the recording film will melt and melt due to the action of the gas pressure and reaction heat generated when the polymer substance melts. Evaporation is promoted.

The opening time of the pit can be shortened.

The present invention was made based on this knowledge, and consists of a mixture of a recording material for heat mode and a low melting point polymer substance that melts at a lower temperature than the recording material on the uneven pattern forming surface of the disk substrate. It is characterized by forming a recording film.

Further, a disk substrate, a recording material, and a low melting point polymeric substance are stored in a vacuum chamber, and sputtering is performed using the recording material and the low melting point polymeric substance as targets to form a mixture of the recording material and the low melting point polymeric substance. The recording film consisting of 1
The manufacturing feature is that it is formed in multiple steps.

〔Example〕

FIG. 1 shows an example of a write-once information recording disk according to the present invention. In this figure, ■ indicates a disk substrate, 2 indicates an uneven pattern formed on one side of the disk substrate l, and 3 indicates a recording film. .

The disk substrate 1 is made of inorganic materials such as glass, polymethyl acrylate (PMMA), polycarbonate,
It is made of plastic materials such as polyvinyl chloride, polypropylene, acrylic, and epoxy.

The concavo-convex pattern 2 is formed on one side of the disk substrate l by a known forming method such as a 2P method, an injection method, a compression method, or an injection-compression method.

The recording film 3 is formed of a mixture of a heat mode recording material and a low melting point polymer substance. Of the two types of substances constituting the recording film 3, any recording material can be used as the recording material for heat mode, but from the viewpoint of sensitivity, S/N ratio, low toxicity, etc., S, Se', Te,
Bi, Sn, Pb, In, Zn.

It is preferable to use one or more elements selected from Mg, Au, Ce, Ca, Sb, Rh, Mn, and Al. In addition, the low melting point polymeric substance is required to have a lower melting point and thermal conductivity than the above-mentioned recording material, and a higher light absorption rate, from this point of view.

Polycarbonate 1. polypropylene, polyethylene,
It is particularly preferable to use one or more polymeric substances selected from nitrocellulose, guanine, or modified products thereof. As a means for forming the recording film 3, any known thin film forming means such as sputtering, vacuum evaporation, ion blating, plasma evaporation, etc. can be used.

Next, an example of a method for manufacturing a write-once optical information recording disc according to the present invention will be described with reference to FIG.

First, a disk substrate, a material for forming an underlayer, and a material for forming a recording film are placed in a vacuum chamber. Next.

The vacuum chamber is evacuated to a predetermined degree of vacuum, and then an inert gas is supplied into the vacuum chamber to adjust the gas pressure within the vacuum chamber to a predetermined value. Next, under the gas pressure conditions described above, one side of the disk substrate is sputtered using the recording material and the low melting point polymer substance as targets to form a recording film.

In this case, instead of storing a target made from a recording material and a target made from a low melting point polymer substance in a vacuum chamber at the same time, the recording material and the low melting point polymer substance are mixed in advance at a predetermined ratio. It is also possible to prepare a mixture and perform sputtering using this as a target.

Further, although the above manufacturing method has been explained using sputtering, it can be performed in exactly the same manner when applying other 1a film forming means such as vacuum evaporation.

Hereinafter, the present invention will be described in detail with reference to specific examples.

First example: First, the UV resin coated on the disk master was spread on a glass plate, the UV411 resin was cured, and then the cured U
V4! A disk substrate 1 having a concavo-convex pattern 2 integrally formed on one side was prepared by transferring the lubricant onto a glass plate. Subsequently, this disk substrate l is used as a recording material T e S
e and polycarbonate, which is a low melting point polymer material, were placed in a vacuum chamber and evacuated to 5×10”Pa, then argon gas was introduced into the vacuum chamber to increase the gas pressure in the vacuum chamber to 5×10”’Pa. In this state, sputtering was performed using the above T e Se and polycarbonate as targets, and a record of 300 people having a composition of T@Se80Vo1% and polycarbonate 20Vo1% was placed on the uneven pattern forming surface side of the disk substrate 1. Film 3 was formed.

Second Example Under the same vacuum conditions as in the first example above, sputtering was carried out targeting a blend of T e S e as a recording material and a blend of nitrocellulose and camphor, which are low melting point polymeric substances. T is formed on the same surface of the disk substrate 1 as shown in the embodiment on the uneven pattern formation side.
A 300-layer recording film 3 having a composition of e5e80Vo1%, nitrocellulose and camphor blend 20Va1% was formed.

In addition, the above-mentioned low-melting point polymeric substance is nitrocellulose with 75%
%, and one containing 25% camphor was used.

Third Example Under the same vacuum conditions as the first and second examples above,
Sputtering was performed using T e S e as a recording material and polypropylene as a low melting point polymer substance as a target, and Te5e80V was sputtered on the uneven pattern formation side of the disk substrate l similar to that shown in the first embodiment.
3 having a composition of o1%, polypropylene 20Vo1%
A recording film 3 was formed for 00 people.

Fourth Example Under the same vacuum conditions as the first to third examples above,
Sputtering was performed using T e S e as a recording material and polyethylene as a low melting point polymer substance as a target, and Te5e80Vo was sputtered on the uneven pattern formation side of the disk substrate l similar to that shown in the first embodiment.
300 with a composition of 1%, polyethylene 20Vo 1%
A human recording film 3 was formed.

The table below shows the write-once optical information recording disks of the first to fourth examples prepared as described above and the write-once optical information recording disks in which the recording film does not contain a low melting point polymer substance. Indicates the minimum recording laser power of Here, the minimum recording laser power is an index indicating the ease with which pits are formed, and refers to the minimum laser power that can form pits in the recording film 3. In the table below, the ratio is expressed when the minimum recording laser power of a Te-3e write-once optical information recording disk not mixed with a low melting point polymer substance is set to 1.

As is clear from the above table, the recordable information recording disk of the present invention in which a low melting point polymer substance is mixed into the recording film 3 has the following characteristics:
In both cases, the minimum recording laser power is lower than that of the conventional product in which a recording film not containing a low-melting point polymer substance is formed, and it can be seen that pits are more likely to be formed in the recording film 3. For each low melting point polymer substance listed in the table above,
In my house, 75% nitrocellulose and 2% camphor.
The 5% blend is the best and can reduce the minimum recording laser power by about half.

In the above embodiment, only the case where a glass plate was used as the disk substrate l was explained, but the gist of the present invention is not limited to this, and other materials such as those formed by injection molding of a polymeric substance, etc. Any disk substrate can be used. Further, in the above embodiment, only the case where T e Se is used as the recording film 3 has been described, but the gist of the present invention is not limited thereto.

In addition, any known recording material for heat mode can be used.

〔Effect of the invention〕

As explained above, according to the present invention, the low melting point polymer substance mixed into the recording film is melted before the DrIIA is melted, and the gas generated when the low melting point polymer substance is melted is mainly Pit is likely to be formed on the recording film due to the effect of gas pressure and exothermic reaction. Therefore, the rotational speed of the information recording disk can be increased during recording, and the access speed and transfer speed during signal reproduction can be increased accordingly.

In addition, since the recording film is mixed with a low melting point polymer substance, the recording film can be formed by performing the thin film forming method once, and the low melting point polymer substance is mixed in advance with the recording film before forming the recording film. Compared to the case where a base layer is formed, the productivity of write-once optical information recording discs can be significantly improved.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a write-once information recording disk according to the present invention, FIG. 2 is a flowchart showing a method for manufacturing the write-once information recording disk according to the present invention, and FIG. 3 is a conventionally known write-once type information recording disk. FIG. 2 is a sectional view showing an example of an information recording disc. 1: Disc substrate, 2: Concave-convex pattern, 3: Recording film Figure 1 1] Disk lever 2: r! ! 3 convex 80 turns 3・t extension Figure 3 Figure 2

Claims (3)

[Claims] (1) In a write-once optical information recording disk in which a recording film is formed on the concavo-convex pattern forming surface of a disk substrate and a pit array corresponding to an information signal is created by irradiating the recording film with a light beam, A recordable optical information recording disk, characterized in that the recording film is formed of a mixture of a heat mode recording material and a low melting point polymer substance that melts at a temperature below the melting temperature of the recording material. (2) Claim 1 characterized in that one or more substances selected from polycarbonate, polypropylene, polyethylene, nitrocellulose, guanine, or modified products thereof are used as the low-melting polymer substance.
A write-once optical information recording disc as described in Section 1. (3) A disk substrate, a recording material, and a low melting point polymer substance are stored in a vacuum chamber, and sputtering is performed using the recording material and low melting point polymer substance as targets, so that the recording material and the low melting point polymer substance are placed on one side of the disk substrate. 1. A method for manufacturing a write-once optical information recording disk, characterized in that a recording film made of a mixture of melting point polymeric substances is formed in one step.