Patent Number: 6,168,207

Title: Optical discs, producing methods and production apparatus of the optical discs

Abstract: The present invention provides an optical disc provided with a watermark inside, which is visible with naked eyes from a reproduction side of the optical disc, and the producing method and the production apparatus thereof. The optical disc comprises a transparent substrate having an information signal recorded surface, a reflective layer formed on the information signal recorded surface thereof, an adhesive layer formed on the reflective layer, a mask layer on the adhesive layer and a transparent dummy substrate on the mask layer stacked in this order. The adhesive layer is made of an adhesive of which curing speed is changed according to a controlled amount of radiation of ultraviolet rays. The watermark is recorded in the optical disc by irradiating the ultraviolet rays on the adhesive through the mask layer provided with light shielding members to cause the adhesive to be cured by controlling a curing speed of the adhesive corresponding to existence or nonexistence of the light shielding members.

Inventors: Nishizawa; Akira (Yokohama, JP)

Assignee: Victor Company of Japan, Ltd.

International Classification: G11B 23/38 (20060101); G11B 23/40 (20060101); G11B 7/26 (20060101); B42D 015/00 ()

Expiration Date: 01/02/2018