MANUFACTURE OF INFORMATION RECORDING SUBSTRATE

摘要

PURPOSE:To obtain a perfectly airtight joining layer and improve quality and durability by providing a projected and recessed fitting parts on the joining face and performing ultrasonic welding. CONSTITUTION:When ultrasonic wave is oscillated pressing an ultrasonic horn 18 from above after holding disks 21' and 31 or disks 21 and 31' between an ultrasonic horn 18 and a base stand 16, frictional heat is concentrated at an annular projection 40 formed in inner and outer peripheral parts of the disc 21' and both corner parts of annular banks of inner and outer peripheral parts of the disk 21 which is in contact with a slanted face 51 of annular grooves formed in inner and outer peripheral parts of the disc 31'. Joining of the disks 21' and 31 and disks 21 and 31' is performed by melting of the projection and corner part.