Process and device for bonding discs to one another

Process for bonding together two disc substrates, each of which has a UV transmissive base, on top of one another with a bonding agent therebetween that is made of a composition which can be cured with UV radiation, at least one of facing sides of disc substrates having an information recording layer thereon which transmits ultraviolet rays and reflects visible rays and which has said bonding agent on a surface thereof, comprising the steps of:

• emitting radiant light which contains ultraviolet radiation toward the disc substrates at least once in a flash using a light irradiation means;
• absorbing light in a range of wavelengths which are absorbed by the the disc substrates from the radiant light emitted using wavelength selection means disposed in an optical path between the light irradiation means and the disc substrates at a distance from the disc substrates, and transmitting ultraviolet rays of said radiant light on to said disc substrates;
• directing cooling air between the light irradiation means and the wavelength selection;
• setting the bonding agent as a result of passage of the ultraviolet rays of the radiant light through the information recording layer and by irradiation of the bonding agent with the ultraviolet rays of the radiant light;
• wherein irradiation of the disc substrates with radiant light is performed in accordance with the relationships:
• E<-7.5+5.9 log .tau. and 88.ltoreq..tau..ltoreq.1000
• where E (J/cm.sup.2) is the electrical energy per irradiated surface which is supplied to the light radiation means which emits the radiant light, and where .tau. (.mu.s) is the duration in which current supplied to the light irradiation means has 1/3 of its peak value, and where log is the common logarithm;
• and wherein at least a main component of which the information recording layer on the at least one of the disc substrates is made is aluminum.