JPH0572660B2 - - Google Patents

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 disk storage device records and reproduces information by irradiating a rotating disk with a laser beam. There is an optical disk used for this purpose called an air sandwich type optical disk.
This disk has a hollow space inside, and usually has two circular substrates on at least one inner surface with a recording layer that can record information using a laser beam. The two are bonded together with a spacer in between, and the hollow portion thus formed is sealed.

Conventionally, when an optical disk is used for a long period of time, errors in recording and reproducing information occur, which has been a problem.

FIG. 2 is a diagram showing the cross-sectional shape of a conventional optical disk. A recording layer 2 is provided on one side of an acrylic resin substrate 1, and the substrate 1 is bonded to the substrate 1 via spacers 4 and 5 so as to form a hollow portion 3 with the recording layer 2 inside. 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 forming on the recording layer due to rapid external temperature changes. That is, 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 optical disc that is free from errors in recording and reproducing information even when stored for a long time.

(Structure of the Invention) The optical disk of the present invention includes two circular substrates, at least one of which has a recording layer on its surface, with the recording layer inside, and a hollow portion between the circular substrates. In the air sandwich type optical disk configured to be formed, the spacer is made of a material with a higher diffusivity than the substrate, and the portion facing the hollow portion is tapered to increase the surface area. It is characterized by being enlarged.

(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 the cross-sectional shape of the optical disk of the present invention.

A tapered inner end spacer 40 is used on the hollow part 3 side. By using a material with a higher thermal diffusivity than the substrate 1 as the material for the spacer 40, information can be recorded in order to prevent dew from forming on the spacer 40 and forming on the recording layer 2 when the optical disk is rapidly cooled.・No playback errors occur. When using this principle, it was not possible to cope with large temperature changes simply by forming the conventional spacer 4 made of a material with a high thermal diffusivity as shown in FIG.
By tapering the side surfaces of the spacer to increase the surface area as in the present invention, it becomes possible to prevent dew condensation on the recording layer 2 even when there is a large temperature change.

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

5-amino-8-(p-ethoxyanilino) was applied to the area from φ45mm to φ114mm on an acrylic resin disk substrate with a guide groove of 15mm inner diameter, 120mm outer diameter, and 1.2mm thickness.
An 800 Å thick organic thin film containing 90% or more of -2,3-dicyano-1,4-naphthoquinone dye was formed as a recording layer. An air sandwich optical disk was produced by bonding two of these disk single plates with an aluminum alloy spacer with an ultraviolet curing resin with the recording layer on the inside. At this time, the outer end spacer was a simple ring with a diameter of 120 mm x 116 mm and a plate thickness of 0.5 mm, but the inner end spacer was a ring with a diameter of 33 mm x 16 mm and a plate thickness of 0.5 mm, tapered 6 mm toward the hollow side. We used one with a wide tip (0.1 mm thick at the tip).

The optical disc produced in this way was heated to 40°C.
Even when stored for a long time in an environment where the temperature rapidly changes to 15 degrees Celsius, errors in recording and playback did not increase.

On the other hand, in the case of a disk using a conventional spacer that does not extend in a tapered shape, errors in recording and reproduction increased in the same environment, confirming the effectiveness of the present invention.

Note that a similar effect was obtained even when the outer end spacer was extended into a tapered shape.

(Effects of the Invention) As is clear from the above embodiments, the present invention makes it possible to obtain an optical disk without recording/reproducing errors even when stored for a long time.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an optical disk according to an embodiment of the present invention, and FIG. 2 is a sectional view of a conventional air sandwich type optical disk. In the figure, 1 is a substrate, 2 is a recording layer, 3 is a hollow part, 4 is an inner end spacer, 5 is an outer end spacer,
40 indicates a tapered spacer.

Claims (1)

[Claims] 1. Air Sun Germany, in which two circular substrates, at least one of which has a recording layer on its surface, are arranged with a spacer interposed therebetween so that a hollow part is formed between the circular substrates with the recording layer inside. 2. A square-shaped optical disc, characterized in that the spacer is made of a material with a higher thermal diffusivity than the substrate, and the part facing the hollow part is extended in a tapered shape to increase the surface area.