INFORMATION SIGNAL RECORDING DISK

摘要

PURPOSE:To reduce the thickness of a disk cartridge by constituting the disk in such a manner that the centering operation to a disk table is executed by using a bulging part formed to enclose a center hole and that the centering operation is assured even if a disk substrate is thin and by housing the above- mentioned bulging part into a cartridge body so as to face the central aperture for admission of a disk table of this body. CONSTITUTION:The bulging part 6 enclosing the center hole 3 is formed on the information signal reading out surface side which is the other main surface 2b side of the disk substrate 2 which is bored with the center hole 3 and is formed with a signal recording layer on the one main surface 2a side.