Method for producing circular optical storage disc

Abstract

In the method of manufacturing a circular optical storage disc (10), there are extensions (21) around the substrate (11) of the optical disc (10) during spin coating of the cover and spacer layers (15). The extension body (21) may consist of one piece or pieces. The outer periphery (23) has a circular or polygonal shape. The extension body is in close contact with the periphery (13) of the disc substrate (11) in the circumferential direction. The surface (22) of the extension is substantially flush with the surface (12) of the base (11) of the optical disc to prevent the flow of spin-coating fluid during spin-coating. The raised edge (16) normally formed at the periphery (13) of the base (11) is now transferred to the outer periphery (23) of the extension (21). After the coating operation, the extension (21) is removed. Reuse of the extension (20) is facilitated by selecting surfaces to which the coating (15) adheres poorly. The optical storage disc is produced with no or very little raised edge (16) and this method does not induce additional birefringence.

Description

technical field [0001] The present invention relates to a method of manufacturing a circular optical storage disc having a substrate with a first surface and an outer periphery, wherein the first surface is provided with a disc formed by applying a liquid, rotating the substrate and solidifying the liquid coating. [0002] The invention also relates to a circular optical storage disc manufactured by the method described above. Background technique [0003] This method is known eg from Japanese patent JP-11086356A. The above-mentioned coating step is known as "spin coating". During spin coating, a plurality of solvent-containing liquids are dispensed onto a substrate, which is then spun. The rotational speed of the substrate is then increased to a higher speed, typically hundreds to thousands of revolutions per minute, depending on the desired layer thickness. Centrifugal force causes radial liquid flow, causing most of the liquid to spin away from the substrate. [0004...

AI Technical Summary

Problems solved by technology

[0008] The disadvantage of this method is that special tools are required to trim the substrate, and particles, dust or flakes that contaminate the disc surface can be formed by the trimming operation

Also, these tools are subject to wear and require frequent replacement

[0009] Another disadvantage is that the trimming operation can induce non-relaxed strain near the substrate near the sheared edge, which can produce optical refraction in the peripheral region of a few millimeters, such as five millimeters, of the substrate when reading or writing through the substrate. discs, which can cause problems

[0010] However, another disadvantage is the use of non-standard oversized substrates with high production costs in optical disc manufacturing

Images