Patent ID: 6704275
Filing Date: 2004-03-09
Classification: B29C,B29L,G11B

Abstract:
A disc cartridge in which a read-write recording medium is encased, the read-write recording medium including a disc having a diameter of 65 mm or less and a thickness between and including 0.4 mm and 0.7 mm, a recording area on the disc extending outwardly from a radial position 12.5 mm or less from a center of the disc, the recording area having a storage capacity of at least 2 Gigabytes, a ratio between the recording area and a non-recording area of the disc being 3.4 or more, the disc cartridge comprising:a cartridge having a rectangular shape and including a first side having a length between and including 52 mm and 70 mm, and a second side, perpendicular to the first side, having a length between and including 52 mm and 70 mm, the cartridge having a thickness between and including 3 mm and 6 mm; at least one opening formed in a side of the cartridge parallel to the read/write recording medium, the opening being a writing and reading access opening through which a radially extending portion of the recording medium is exposed to a light beam from an optical pickup and through which a magnetic-clamping hub is exposed, the opening further being formed deviated to one lateral side from a middle point of a front side of the cartridge; a center hole formed through the center of the disc; and an annular table-abutment integrally formed as a part of the disc around and adjacent the center hole and being convex to one side of the disc, the annular table-abutment having a recessed portion having a surface that faces away from the one side of the disc and recessed toward the one side of the disc, the hub being fixed to a the surface of the recessed portion of the annular table-abutment, the hub having a flange portion fixed to the surface of the recessed portion of the table-abutment on the surface of the table-abutment that faces away from the one side of the disc and a depressed portion depressed from the flange portion into the center hole toward the one side of the disc, a height of the hub from a lower surface of the depressed portion to an upper surface of the flange portion being smaller than a thickness of the table-abutment.