JPH06309700A - Optical recording medium - Google Patents

Abstract

PURPOSE:To prevent deterioration of layers and warpage of a substrate which cause reading errors, by forming a protective layer containing a polymer compd. having a specified chemical structure as the repeating unit. CONSTITUTION:This medium has a protective layer on a substrate, and this protective layer contains a polymer compd. having the compd. expressed by the formula as the repeating unit. In the formula, R is an alkyl group of 2-4 carbon number and (n) is an integer. Thereby, during or after forming the protective layer, warpage or deterioration of layers as a reflecting layer, dielectric layer, and recording layer can be prevented, and the obtd. optical recording medium has higher durability.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical recording medium with less reading error.

[0002]

2. Description of the Related Art In a recording / reproducing system of an optical recording medium, a pit is formed on a substrate and information is read by scattering or interference of reflected light by the pit, and a recording layer such as a dye is provided on the substrate to perform the recording. There are various methods such as a method of forming pits in a layer and reading information by scattering or interference of reflected light by the pits, or a method of reading information from the magneto-optical effect of the recording layer by giving perpendicular magnetic characteristics to the recording layer. There are different types.

In order to read a change in light intensity or a minute change in polarization angle, alteration of various layers formed on a substrate caused by the influence of humidity or temperature in any of the above optical recording media, the substrate And the like cause a read error. Therefore, a protective layer is provided in order to prevent alteration of the various layers and distortion of the substrate.

[0004] For the protective layer, generally, an ultraviolet curable resin which can be cured by UV irradiation after being coated with a solvent by a spin coating method is preferably used because the manufacturing process is simple.

[0005]

However, in the conventional optical recording medium using the ultraviolet curable resin for the protective layer, the contraction pressure generated at the time of curing the ultraviolet curable resin and the high pressure mercury lamp which is the source of the ultraviolet ray generate the ultraviolet curable resin. The heat may cause deterioration of various layers formed on the optical recording medium and distortion of the substrate.

Since the polyfunctional acrylate monomer used as an ultraviolet curable resin has a glass point transfer of around 120 ° C., it may undergo thermal expansion or contraction even after curing depending on the use environment, which may result in alteration of various layers or substrate. May cause distortion.

The above-mentioned alteration of layers and distortion of the substrate cause a read error when the optical recording medium is used for a long period of time. An object of the present invention is to provide an optical recording medium that does not cause alteration of layers and distortion of a substrate.

[0008]

The gist of the present invention is to provide an optical recording medium having at least a protective layer on a substrate, wherein the protective layer is a polymer containing a compound represented by the following general formula as a repeating unit. An optical recording medium containing a compound.

[0009]

[Chemical 2]

[0010]

Since the optical recording medium of the present invention uses the compound shown in Chemical formula 1 as the protective layer, the properties of the reflective layer, the dielectric layer and the recording layer formed on the substrate during and after the formation of the protective layer are deteriorated. Does not cause substrate distortion.

[0011]

EXAMPLES Examples will be described below, but the present invention is not limited thereto.

(Example 1) S on a polycarbonate substrate
Dielectric layer made of iO, recording layer containing TbFeCo, Si
Three dielectric layers of O were sequentially formed by the sputtering method. Poly (2,5-dibutoxyphenylene) obtained by the method disclosed in JP-A-58-113221
(Hereinafter abbreviated as PDBP) was dissolved in toluene. The solution is applied onto the reflective layer by spin coating to form a protective layer of PDBP having a thickness of 3 to 5 μm, and then left in an atmosphere of 60 ° C. for 5 minutes to volatilize the solvent to obtain an optical recording medium. It was

(Comparative Example-1) Example 1-except that a UV curable resin XNR-5461 (manufactured by Nagase Ciba Co., Ltd.) was used as the protective layer and the resin was cured by irradiating it with ultraviolet rays. An optical recording medium was obtained in the same manner as in 1.

The TI immediately after the production of the optical recording medium obtained above
The value of LT angle was measured. Further, in order to examine the durability performance, the optical recording medium was heated at a temperature of 85 ° C. and a relative humidity of 85% R.V. H.
The value of the TILT angle was measured after standing for 2000 hours in the environment. The TILT angle is ISO standard CD-100.
It measured using the evaluation apparatus based on 90.

The results are shown in Table 1. The maximum value of the TILT angle that can be practically endured is 5 mrad.

[0016]

Table 1 TILT angle immediately after production TILT angle after endurance test Example-1 2mrad 2mrad Comparative example-1 5mrad 6mrad As is clear from Table 1, the optical recording medium of the present invention has a conventional durability. It is superior and the TILT angle does not exceed 5 mrad even after the durability test. PDBP
A solution in which 20 mol% of iodine was dissolved in the solution was prepared, and the conductivity between the solution in which the iodine was dissolved and the PDBP solution was measured. The former showed 10 ⁻⁹ Ω ⁻¹ cm ⁻¹ , and the latter did not show conductivity. When an optical recording medium was manufactured by applying the liquid in which the iodine was dissolved as a protective layer, dust and the like were difficult to adhere to the protective layer because the protective layer had conductivity.

For this reason, since dust and the like are not adhered to the protective layer when the bonded optical recording medium in which the protective layers of the two recording media are bonded to each other is manufactured, it is easy to apply the adhesive to the protective layer. Therefore, it is possible to obtain a bonded optical recording medium which is hard to peel off.

[0018]

The optical recording medium of the present invention has excellent durability and does not cause a reading error even when used for a long period of time.

Claims (1)

[Claims] 1. An optical recording medium having at least a protective layer on a substrate, wherein the protective layer contains a polymer compound containing a compound represented by the following chemical formula 1 as a repeating unit. recoding media. [Chemical 1]