Patent ID: 6780262
Filing Date: 2004-08-24
Classification: B29C,B29L,G11B

Abstract:
A method for manufacturing a multilayer disc by bonding one disc to another disc, the method including steps of:fixing, by a disc fixing means, the one disc in place; supporting, by a supporting means, said another disc; projecting, by a light projecting means, a light onto a boundary between an embossed signal recording area and non-signal recording area on the one disc fixed in place; capturing, by a return light capturing means, a return light from the boundary illuminated with the light projected from the light projecting means, the return light being captured from the boundary at four observation areas, the four observation areas being circumferentially disposed around the boundary at intervals of 90 degrees; determining the center of the signal recording area on the one disc based on a information as to the signal recording area, acquired in the return light capturing step; varying, by a relative position varying means, the center of the signal recording area on said another disc in relation to the disc fixing means in order to align the center of the signal recording area of the one disc, determined in the area center determining step, with the centering means; and bonding the one disc and other disc to each other.