To achieve the same margin as that of the digital versatile disk (DVD), usi
ng a 0.4 mm substrate has been molded for a high-density optical disk for d
ouble-sided dual laver disk. In this paper, the characteristics of a read-o
nly and rewritable high-density optical disk of 0.4 mm plastic substrate is
reported using a new resin material for injection molding, to improve both
the birefringence and the mechanical characteristics.