JPS61180946A - Information recording disk - Google Patents

Abstract

PURPOSE:To obtain the title information recording disk with less warpage, waviness and aged detrioration by forming a protective layer consisting of an UV ray-curing resin contg. an UV absorbent on a transparent disk having an information recording layer. CONSTITUTION:An information recording layer 2 obtained by vapor-depositing tellurium oxide is provided on one surface of a disk 1 formed by injection molding of an acrylic resin. Two disks 1 are stuck to the recording layer 2 face to face with each other with an adhesive 3 to form a laminated disk. Then an UV ray-curing protective coat liq. contg. an UV absorbent is coated over the whole surface of the laminated disk, and the disk is rotated at high speed to uniformize the liq. Thereafter, the liq. is cured by irradiating UV rays to form a protective layer 7 contg. the UV absorbent. The greater part of the UV rays for curing acts on the UV ray-curing protective coat liq., and the liq. can be cured efficiently and completely. Consequently, an information recording disk with less warpage and waviness can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an information recording disk that can be used in an optical information recording and reproducing apparatus.

BACKGROUND OF THE INVENTION In recent years, the amount of information handled in offices and homes has increased dramatically, and there is a demand for information recording and reproducing devices that can record large amounts of information and stably store and reproduce over a long period of time. In response to this situation, optical disk devices and magneto-optical disk devices that use laser light to record and reproduce information without contact have been put into practical use, replacing the contact-type magnetic recording method that had been mainly used in the past. It's coming.

Therefore, the information recording disks used in these devices must be able to retain information stably for long periods of time and maintain their appearance, no matter how harsh the environment or how they are handled. There is.

Hereinafter, a conventional information recording disc will be explained with reference to the drawings. FIG. 2 is a sectional view of a conventional information recording disk. In the figure, after an information recording layer 2 is formed on a disk 1 made of a transparent material having good transmittance to laser light, such as acrylic resin, polycarbonate resin, or glass, by means such as vacuum evaporation or sputtering, the disk 1 is Paste the two pieces together with adhesive 3 to make a pasted disc 4. After that, while rotating the bonded disk 4 at a relatively low speed, an ultraviolet curable protective coating liquid is poured over all surfaces of the bonded disk 4, and then the bonded disk 4 is rotated at a high speed. By rotating, the UV-curable protective coating liquid on the surface is made uniform, and then ultraviolet rays are irradiated to harden the UV-curable protective coating liquid. As a result, the protective layer 6 is formed over the entire surface of the bonded disc 4, thereby completing the information recording disc.

Problems to be Solved by the Invention However, in the conventional configuration as described above, the ultraviolet rays irradiated when curing the ultraviolet curable protective coating liquid to form the protective layer are also absorbed by the disk 1. This causes an increase in the temperature of the plate 1, causing warping or waviness in the bonded disc 4, which narrows the dynamic range of optical pickup using laser light, or in the worst case, makes it impossible to focus. However, there was a problem in that normal recording and playback could not be performed if the

Even during storage, there is still a problem in that ultraviolet rays contained in sunlight pass through the protective layer 5 and the disc 1 and act on the information recording layer 2, deteriorating the characteristics of the information recording layer 2. Ta.

In view of the above-mentioned problems, the present invention has been developed to reduce warpage and waviness,
An object of the present invention is to provide an information recording disk for an optical information recording/reproducing device that is capable of stable recording/reproducing and has little change over time.

Means for Solving the Problems The information recording disk of the present invention is characterized in that the protective layer formed on the surface of the transparent disk having the information recording layer contains an ultraviolet absorber.

Effect The information recording disk of the present invention has the above-described configuration.
Most of the ultraviolet light that is irradiated to cure the UV-curable protective coating liquid is absorbed by the UV-curable protective coating liquid and not directly absorbed by the disc, so no warping or α-curvature occurs in the bonded disc. . Further, even after curing, even if ultraviolet rays contained in natural sunlight act, they are absorbed by the protective layer and do not reach the information recording layer, so the information recording layer will not deteriorate.

Example Hereinafter, regarding an information recording disk according to an example of the present invention,
This will be explained with reference to the drawings. FIG. 1 shows a sectional view of an information recording disk according to an embodiment of the present invention.

In FIG. 1, a disk 1 made by injection molding of acrylic resin has a center hole 6 in its center to be engaged with a rotary table of an information recording device, and one surface has tellurium oxide. The material has an information recording layer 2 that is vacuum-deposited. Two disks 1 are bonded together with an adhesive 3 with the information recording layers 2 facing each other to create a bonded disk 4.

After that, an ultraviolet curable protective coating solution containing an ultraviolet absorber is poured onto all surfaces of the bonded disc 4, and the ultraviolet curable protective coating solution containing an ultraviolet absorber is uniformized by rotating at high speed. An absorbent-containing protective layer 7 is formed to provide an information recording disk.

According to the information recording disk of this embodiment configured as described above, the ultraviolet absorber-containing protective layer is formed on the surface of the information recording disk by curing the ultraviolet curable protective coating liquid containing the ultraviolet absorber. Therefore, during curing,
Most of the UV rays for curing act on the UV curable protective coating solution, allowing it to be cured more efficiently and completely, resulting in improved surface hardness of the protective layer and shorter curing time. It will be done.

Furthermore, since the temperature rise of the bonded disks is also reduced, there is an effect that warping and waviness do not occur.

Furthermore, even after curing, the protective layer absorbs ultraviolet rays from natural sunlight to protect the information recording layer and prevent deterioration of its characteristics.

Although the above embodiment has a structure in which two disks 1 having the information recording layer 2 are pasted together, it is also possible to bond two disks having only one of the two disks having the information recording layer.
Furthermore, a single-plate structure with only one disc and no bonding may be used.

In addition, although the disc is made by injection molding acrylic resin, the material is not limited to this, for example, the material may be polycarbonate resin or glass that allows laser light for information recording and reproduction to pass through. Any material can be used as long as it is suitable. Also, the manufacturing method can be, for example, by pouring an ultraviolet curable resin between the stamper and the base material, curing it with ultraviolet light, and then integrating the base material and the cured resin to make the stamper. A method in which the film is peeled off from the substrate (a method generally referred to as the 2P method) may also be used.

The material of the information recording layer is not limited to tellurium oxide, and may be, for example, tellurium carbide, tellurium-selenium alloy, gadolinium-cobalt, terbium-iron, aluminum, or the like.

Effects of the Invention As described above, according to the present invention, the ultraviolet absorber-containing protective layer formed by curing the ultraviolet curable protective coating liquid containing an ultraviolet absorber is formed on the surface of the information recording disk. It can be efficiently and completely cured, and a highly hard surface can be obtained in a shorter time than conventional methods. Furthermore, an information recording disk with little warpage or waviness can be obtained. Furthermore, a remarkable effect can be obtained in terms of characteristic deterioration due to external ultraviolet rays during storage.

[Brief explanation of drawings]

FIG. 1 is a sectional view of an information recording disk according to an embodiment of the present invention, and FIG. 2 is a sectional view of a conventional information recording disk. 1... Disk, 2... Information recording layer, 3.
...adhesive, 7...protective layer containing ultraviolet absorber. Name of agent: Patent attorney Toshio Nakao and 1 other person71
...1 Krill #tM Toyamoto I2...94 Silicon Chaos Tun 15... Akunor Book Agreement 14 Red 4ri Diagram 2 Procedural Amendment February 7, 1985 2 Name Information Record of Invention Relationship with Disc 3 Amendment Case Patent Application
Address: 1006 Kadoma, Kadoma City, Osaka Prefecture
Name (582) Matsushita Electric Industrial Co., Ltd. Representative Toshihiko Yamashita 4 Agent 571 Address 1006 Oaza Kadoma, Kadoma City, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. / 1 + 1 Subject to 6 amendments

Claims (2)

[Claims] (1) An information recording disk in which a protective layer made of an ultraviolet curing resin containing an ultraviolet absorber is formed on the surface of a transparent disk having an information recording layer. (2) Claim 1, wherein two transparent disks having an information recording layer on at least one surface are joined together, and a protective layer made of an ultraviolet curing resin containing an ultraviolet absorber is formed on the surface thereof. Information recording disk listed.