Abstract: Optical disc manufacturing apparatus of the present invention comprises a nozzle for ejecting TV curable cationic composition, ultraviolet radiation means for radiating ultraviolet rays while the UV curable cationic composition dropping from the nozzle reaches a disc substrate; and superimposing means for superimposing the two disc substrates one upon another by allowing planes onto which the UV curable cationic composition is dropped to be faced. To allow the UV curable cationic composition to spread between the two disc substrates superimposed by the superimposing means: a statically placing plane for placing the disc should be provided. A stacking means for stacking the plurality of discs and rigid disc placing means for placing a rigid disc having a flat plane on the disc in the course of stacking the plurality of discs should be provided.

Abstract: Ultraviolet rays are irradiated in a space through which a cationic ultraviolet curable composition falling from a nozzle passes before reaching a disc substrate. The cationic ultraviolet curable composition which has been irradiated with ultraviolet rays, is distributed in a ring form on the surface of the disc substrate. Another disc substrate is then superposed in this distributed surface to spread the composition by pressing or by the weight of the other disc substrate itself.

Abstract: The present invention relates to a method for bonding together two disc substrates, at least one disc substrate having a UV transmissive-visible light reflective information recording layer provided on a UV transmission base. In this method, the disc substrates are bonded together, so that the information recording layer of one disc substrate faces the other disc substrate, by employing UV irradiation to cure a UV curable composition used as a bonding agent. In the case of the present invention, to cure the bonding agent, UV is irradiated in a single or repeating flash so as not to impair the information recording layer. As a result, the bonding agent can be cured in a shorter period of time with less energy consumed as compared to the conventional method of using conditions irradiation of UV light to cure a UV curable composition used as a bonding agent. Accordingly, the present method enables a product disc to be obtained in a shorter time, with less energy used, so that productivity (i.e.

Abstract: A method for measuring dishing in discs, including the steps of irradiating a laser beam along a scanning line which spirals from an inner side to an outer side of a surface of a magneto-optical disc or a digital video disc; determining a tilt angle at each of a plurality of measurement points on the scanning line based on displacement of a reflected laser beam from a normal reflected position; and using a measurement point on a first circuit on the inner side of the scanning line as a reference to determine dishing amounts at corresponding measurement points on circuits after the first circuit based on the tilt angles.

Abstract: The present invention relates to a method for bonding together two disc substrates, at least one disc substrate having a UV transmissive-visible light reflective information recording layer provided on a UV transmissive base. In this method, the disc substrates are bonded together, so that the information recording layer of one disc substrate faces the other disc substrate, by employing UV irradiation to cure a UV curable composition used as a bonding agent. In the case of the present invention, to cure the bonding agent, UV is irradiated in a single or repeating flash so as not to impair the information recording layer. As a result, the bonding agent can be cured in a shorter period of time with less energy consumed as compared to the conventional method of using continuous irradiation of UV light to cure a UV curable composition used as a bonding agent. Accordingly, the present method enables a product disc to be obtained in a shorter time, with less energy used, so that productivity (i.e.