Optical disc and disc cartridge

A disc cartridge accommodating a disc comprised of two disc substrates bonded together, said disc being non-symmetrical in cross-section about a bonding center line, comprising:

• a main cartridge body portion forming a disc housing and having an aperture via which to insert and take out said disc to and from said disc housing and further having two rib-like retainers extending from said aperture into said disc housing, so that said aperture has a shape substantially identical to the non-symmetrical cross-section of the disc, whereby said aperture is configured for accommodating said disc only in one orientation corresponding to a state of permitting recording and/or reproduction of said disc;
• and
• an opening/closure mechanism for opening/closing said aperture, including a takeout inhibiting mechanism specifying whether recording on said disc is possible, said takeout inhibiting mechanism, when in a state of inhibiting recording on the disc, inhibiting takeout of the disc from said main cartridge body portion, and the opening/closing movement of the opening/closure mechanism being inhibited when said inhibiting mechanism specifies a state of inhibiting recording on said disc, said takeout inhibiting mechanism including a discriminating member specifying whether recording on the disc is possible, said discriminating member being mounted for movement between a first position specifying the state of inhibiting recording on said disc and a second position specifying a state of possible recording on said disc, and wherein said main cartridge body includes a discrimination opening into which said discrimination member is intruded.

A disc cartridge accommodating therein a disc non-symmetrical in cross-sectional shape relative to a center line of the disc in a thickness direction, comprising:

• a main cartridge body portion forming a disc housing and having an aperture via which to insert or take out a disc to and from said disc housing and further having two rib-like retainers extending from said aperture into said disc housing, so that said aperture has a shape substantially identical to the non-symmetrical cross-section of the disc, whereby said aperture is formed for accommodating the disc only in one orientation corresponding to a state permitting recording and/or reproduction of the disc;
• and
• an opening/closure mechanism for opening/closing said aperture, including a takeout inhibiting mechanism for specifying whether recording on the disc is possible and when in the state of inhibiting recording on the disc for inhibiting takeout of said disc from said main cartridge body portion, said takeout inhibiting mechanism including a discriminating member movably mounted on said opening/closing mechanism for specifying whether recording on the disc is possible and being mounted for movement to a first position of being exposed through a control opening when specifying the state of inhibiting recording and for movement to a second position of being exposed through said control opening when specifying the state of possible recording, wherein said discriminating member, when moved to said first position is engaged with and retains the disc.