Structure of optical disc cartridge

In a disc casing for receiving a disc being released by a disc holder insertable into the casing, the casing being provided with supporting ribs on inner surfaces thereof for supporting a non-recordable clamping region of the disc for thereby preventing contact between recordable regions of the disc and the inner surfaces of the casing, the improvement:

• wherein a height of the supporting ribs is set according to the following formula:
• Hopt=G+D+A
• wherein Hopt is the height, G is the deflection of the disc due to gravity, D is a deformation of the disc holder, and A is the predetermined clearance gap between the disc and a pair of flanges on the disc holder, with the pair of flanges being in parallel with respect to the disc.

A disc cartridge comprising:

• a casing for receiving a disc therein;
• a disc holder insertable into the casing, the disc holder having arms that grasp the disc therebetween, and that release the disc onto the support member when the disc holder is completely inserted into the casing, the disc holder arms remaining aligned with the periphery of the disc released onto the supporting member, each arm including an upper and lower flange in parallel with respect to the disc and a groove formed between the flanges for receiving an outer circumferential edge of the disc;
• a supporting member provided within the casing, the supporting member having a particular configuration that allows the disc to be supported thereon to provide enough clearance between the disc and the inner surfaces of the casing a height of the supporting member being determined according to a deflection of the disc, a deformation of the disc holder arms and a predetermined clearance gap between the disc and the flanges.