Patent ID: 7555763

Claim:
A disc cartridge comprising: a disc; and a main cartridge body unit including an upper cartridge portion and a lower cartridge portion, the main cartridge body unit having said disc rotatably housed therein and including: a recording and/or reproducing aperture formed into the lower cartridge portion that exposes a portion of said disc to outside across inner and outer rims of said disc, the recording and/or reproducing aperture defining a first side of the lower cartridge portion and a second side of the lower cartridge portion, and an entrance part for a head unit of a recording and/or reproducing apparatus, said entrance part being a recess which is formed in the first side of the lower cartridge portion and extending to said recording and/or reproducing aperture, for entrance of at least a portion of said head unit below an outer surface of the lower cartridge portion, wherein a lateral surface of said entrance part for said head unit is an inclined surface for inhibiting abutment against said head part, and wherein a depth of said entrance part is less than a thickness of the first side of the lower cartridge portion so as to not expose another portion of the disc located adjacent to the recess to the outside.