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

An optical disc producing method for producing an optical disc comprising 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 and a dummy transparent substrate on the adhesive layer stacked in this order, the method comprising the steps of:

• forming the reflective layer on the information signal recorded surface of the transparent substrate;
• coating an adhesive on the reflective layer to form the adhesive layer, wherein a curing speed of the adhesive is changeable according to a controlled amount of irradiation of electromagnetic radiation rays;
• disposing the dummy transparent substrate on the transparent substrate sandwiching the reflective layer and the adhesive layer;
• forming a mask pattern directly on a top surface of the dummy transparent substrate, wherein the mask pattern has a specific shape partially shields the electromagnetic radiation rays;
• and
• irradiating the electromagnetic radiation rays on the adhesive layer through the mask pattern formed on the dummy transparent substrate to cause the adhesive to be cured by being controlled of an amount of irradiation of the electromagnetic radiation rays corresponding to the specific shape, whereby a position of the reflective layer is microscopically and partially displaced corresponding to the specific shape from an original position of the reflective layer;
• and thus displaced displacement of the reflective layer visually exhibits a watermark having the specific shape after the adhesive is cured.

An optical disc producing method for producing an optical disc comprising 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 dummy transparent substrate on the mask layer stacked in this order, the method comprising the steps of:

• forming the reflective layer on the reflective layer of the transparent substrate;
• coating an adhesive on the information signal recorded surface to form the adhesive layer, wherein a curing speed of the adhesive is changeable according to a controlled amount of irradiation of electromagnetic radiation rays;
• disposing the dummy transparent substrate on the adhesive layer sandwiching the mask layer therebetween, wherein the mask layer has a specific pattern for partially shielding the electromagnetic radiation rays;
• and
• irradiating the electromagnetic radiation rays on the adhesive layer through the mask layer to cause the adhesive to be cured by controlling an amount of irradiation of the electromagnetic radiation rays corresponding to the specific pattern, whereby a position of the reflective layer is microscopically displaced corresponding to the specific pattern, and thus displaced reflective layer visually exhibits a watermark having the specific pattern after the adhesive is cured.

An optical disc producing method for producing an optical disc comprising a first 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, mask means having masking members and a second substrate, the method comprising the steps of:

• forming the reflective layer on the information signal recorded surface of the first substrate;
• coating an adhesive on the reflective layer to form the adhesive layer, wherein a curing speed of the adhesive is changeable according to a controlled amount of irradiation of electromagnetic radiation rays;
• disposing the second substrate on the first substrate sandwiching the reflective layer and the adhesive layer;
• disposing mask means having the mask members on one surface of the second substrate;
• irradiating the electromagnetic radiation rays on the adhesive through the mask means to cause the adhesive to be cured by controlling the curing speed of the adhesive responsive to existence and nonexistence of the mask members, whereby a watermark is recorded in the optical disc corresponding to the existence and nonexistence of the mask members after the adhesive is cured.

An optical disc production apparatus for producing an optical disc comprising a first 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, and a second substrate on the adhesive layer stacked in this order, the adhesive layer made of an adhesive of which curing speed is changed according to a controlled amount of irradiation of an electromagnetic radiation rays, the apparatus comprising:

• an electromagnetic radiation rays source;
• mask means provided with mask members for partially shielding the electromagnetic radiation rays emitted from the electromagnetic radiation rays source;
• and
• disc mounting means for mounting the optical disc;
• wherein a watermark is recorded in the optical disc by irradiating the electromagnetic radiation rays on the adhesive through the mask means to cause the adhesive to be cured by controlling the curing speed of the adhesive corresponding to an existence and nonexistence of the mask members.