Ventilation arrangement for use in an optical recording disc

Abstract

An optical recording disc comprising two disc substrates, each in a cylindrical shape having a round center hole, at least one recording layer formed on the surface of at least one said disc substrate, and at least one bonding material layer is formed at an inner rim portion and an outer rim portion of the surface of the said disc substrate, on the surface of which the recording layer is formed, except for at least one portion of the said rim portion of the surface of the disc substrate, wherein the bonding material layer is provided to bond the said two disc substrates togehter, so that the surfaces of the said disc substrates, on the surface of which the recording layer is formed, face each other, thereby a space gap is formed between the said disc substrates, and the said one portion of the said rim portion of the surface of the disc substrate, where the bonding material layer is not formed, can act as a ventilation path, through which the air can pass from the said air gap into the outside of the optical recording disc, and reversely. Accordingly, the said ventilation path enables to prevent the shape of the disc substrate from changing and also enables to prevent the disc substrate from breaking, even if there is a pressure difference between the inside air gap and the outside of the optical recording disc, thereby the optical recording disc can record information correctly on the recording layer.