US Patent 7287265 Disk cartridge

A disk cartridge housing an optical disk is provided, a rotation wheel is housed rotatably in a cartridge body and which houses the disk and has formed therein a second opening corresponding to a first opening and through which the housed disk is exposed to outside, and a pair of shutter plates which are pivoted in conjunction with the rotation of the rotation wheel to uncover the first and second openings when the latter coincide with each other. The rotation wheel has formed at the front side thereof, at which the disk cartridge is first inserted into a disk recorder and/or player, a to-be-operated portion in which a shutter releasing portion of the disk recorder and/or player is engaged, and the to-be-operated portion is formed from a concavity opening the front side of the disk cartridge at which the latter is first inserted into the disk recorder and/or player.