JPS61180947A - Optical disk - Google Patents

Abstract

PURPOSE:To obtain an optical disk which is free from the recording/ reproduction errors of information despite the long-time storage of the disk, by providing a dew condensation layer in addition to a recording layer on a substrate at the side of a hollow part. CONSTITUTION:A dew condensation layer 20 is provided on a substrate 1 at the side opposite to a hollow part 3. The layer 20 uses a material larger in heat diffusivity than a recording layer 2. Thus the dew is produced on the layer 20 when an optical disk is cooled suddenly. In such a way, the generation of dew on the layer 2 is prevented. As a result, no recording/reproduction error is produced with information.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to the structure of an optical disk used in an optical disk storage device.

(Prior art and its problems) An optical disc storage back cover records and reproduces information by irradiating a rotating disc with a laser beam. The original disk used for this is called an air sandwich type optical disk.

This disc has a hollow space inside, and usually has two circular substrates with a recording layer on at least one inner surface that can record all information using a laser beam, with an outer edge and an inner edge. They are then bonded together with a spacer in between, and the hollow portion thus formed is sealed.

Conventionally, when such optical discs are used for a long time, errors occur in recording and reproducing information, which has been a problem.

FIG. 3 is a diagram showing the cross-sectional shape of a conventional original disk.

A recording layer 2 is provided on one side of the acrylic resin substrate l, and the recording layer 2
spacer 4.5 to form the hollow part 3 with
It has a structure in which the substrate 1 is bonded through the hollow part 3.
is sealed from the outside air. When investigating the cause of recording/reproduction errors occurring when such optical discs are used for long periods of time, it was found that this is due to dew formation on the recording layer due to rapid external temperature changes. In other words, if a disk that has been in a warm environment is suddenly brought into a cold environment, dew will form on the recording layer, and this dew will react with the recording layer, thereby degrading the recording and reproducing characteristics.

(Objective of the Invention) An object of the present invention is to provide an original disk that is free from errors in recording and reproducing information even when stored for a long time.

(Structure of the Invention) The original disk of the present invention has a plurality of circular substrates each including at least one circular substrate having a recording layer on its surface, and a hollow portion is formed between the substrates with the recording layer inside through a spacer. In the air sandwich type original disk having the same structure, a dew condensation layer is provided on the substrate on the inner part side, in addition to the recording layer.

(Detailed Description of Configuration) The present invention solves the problems of the prior art by adopting the above-described configuration.

The present invention will be explained below with reference to the drawings.

FIG. 1 is a diagram showing an example of the cross-sectional shape of the optical disc of the present invention. A dew condensation layer 2 (l) is provided on the surface of the substrate l facing the hollow part 3.
By providing this material as the dew condensation layer 20, dew is prevented from forming on the dew condensation layer 20 and the recording layer 2 when the original disk is rapidly cooled, thereby preventing errors in recording and reproducing information. , FIG. 2 is a diagram showing an example of the cross-sectional shape of another original disk. A dew condensation layer 30 is provided on the surface of the substrate l facing the hollow portion 3. The dew condensation layer 30 passes between the inner end spacer 4 and the substrate 10 and is connected to the circular hole 31. By providing the dew condensation layer 30 with a material having a higher thermal diffusivity than that of the recording layer 2, dew forms on the dew condensation layer 30 and dew on the recording layer 2 when the original disk is rapidly cooled. In order to prevent this, errors in recording and reproducing information will not occur.

(Example) Examples of the present invention will be described below.

A guide groove having an inner diameter of 15 mm and an outer diameter of 120 m and a thickness of 1.2 mm was formed to form a dew condensation layer. Next, change the vapor deposition mask and
82 whose main component is amino-8-(p-ethoxyanilino)-2,3-dicyano-1゜4-naphthoquinone dye
An organic thin film having a thickness of 5A was formed as a recording layer as shown in FIG. Next, two such substrates were bonded together using an inner end spacer and an outer end spacer made of acrylic resin as shown in FIG. 1, and the naphthoquinone dye recording layer was sealed in the hollow part.

The original disk produced in this way was heated to 150°C from 40°C.
Recording/playback errors did not increase even when stored for a long time in an environment where the temperature rapidly changes.

When a similar evaluation was performed on a disc without a dew condensation layer, errors in recording and reproduction increased, which confirmed the effectiveness of the present invention in which a dew condensation layer was provided.

When the dew condensation layer was provided as a Ti film with a thickness of 800^ as shown in Fig. 2 and evaluated in the same manner as in Example 1, there was no increase in recording/reproducing errors.

(Effects of the Invention) As is clear from the above embodiments, the present invention makes it possible to obtain a disc with no errors in recording or reproduction even when stored for a long time.

[Brief explanation of drawings]

FIG. 1 is a sectional view of the original disk according to an embodiment of the present invention, and FIG.
The cause is a cross-sectional view of an original disk according to another embodiment of the present invention, and FIG. 3 is a cross-sectional view of a conventional air sandwich type original disk. In terms of rotation pressure, 1 is a substrate, 2 is a recording layer, and 3 is a hollow part, 4 is the inner end, spacer, 5 is the outer end spacer, 20.30
indicates a dew condensation layer, and 31 indicates a circular hole. Procedural amendment (spontaneous) November 3, 1980 - η 1. Indication of the case 1982 Patent Application No. 277304 2. Title of the invention Optical disk 3. Person making the amendment Relationship to the case Applicant Shiba, Minato-ku, Tokyo 5-33-1 (423) NEC Corporation Representative: Tadahiro Sekimoto 4, Agent: Sumitomo Sanda Building, 5-37-8 Shiba, Minato-ku, Tokyo 108 Telephone: Tokyo (03) 456-3111 (main representative) 5 ,
Column 6 of Detailed Description of the Invention of the Specification Subject to Amendment, Contents of the Amendment 1) The text "l"'l 50J on page 5, line 18 of the specification is amended to "15". 〆11 patent attorneys inside ('Jin・1.-5-''

Claims (2)

[Claims] (1) At least one circular substrate with a recording layer on its surface
In an air sandwich type optical disk having a structure in which a hollow part is formed between the plurality of circular substrates with the recording layer inside through a spacer, a dew condensation layer is placed on the hollow part side separately from the recording layer. An optical disc characterized by being provided on a substrate. (2) The optical disc according to claim 1, wherein the recording layer is a thin film mainly composed of an organic thin film.