| 摘要 |
PURPOSE: A compact disc is developed to align a seating centering regardless of a cylinder of a seating portion of the compact disc when the compact disc is seated on the seating portion of a disc tray. CONSTITUTION: The compact disc comprises on a center thereof a through hole(401h) for receiving a center shaft of a turntable, a data recording area(401r) recorded with a data to a predetermined area around the through hole, and a protrusion(401t) for aligning a seating centering to a seating portion for a 8 centimeters compact disc of a disc tray. The protrusion is made in an arc shape corresponding to an outer periphery of the seating portion for 8 centimeters compact disc of the disc tray. The protrusion is made to slide along the outer periphery of the seating portion. When the compact disc is seated onto the seating portion, the protrusion is located in corresponding to the outer periphery of the seating portion, with the disc being exactly centered. |
