AN OPTICAL DISC WITH COAXIALLY ALIGNMENT OF THE SIGNAL CENTER AXIS AND THE HUG CENTER AXIS

摘要

An optical disc includes a first substrate (202a) having a first central opening (204a), a first signal layer (210a) formed on one of the surfaces of the substrate (202a), a second substrate (202b) having a second central opening (204b), a second signal layer (210b) formed on one of the surfaces of the second substrate (202b), and a hub (212) having a central longitudinal axis. The first substrate (202a) and the first signal layer (204a) are designed such that a first central longitudinal axis of the first opening (204a) substantially coaxially aligns with a first central longitudinal axis of the first signal layer (210a), and the second substrate (202b) and the second signal layer (210b) are designed such that a second central longitudinal axis of the second opening (204b) substantially coaxially aligns with a second central longitudinal axis of the second signal layer (210b). The first substrate (202a), the second substrate (202b) and the hub (212) are bonded together with the result of substantially coaxially alignment of the central longitudinal axis of the first signal layer (210a), the second signal layer (210b) and the hub (212).