Patent ID: 7101171

Claim:
A molding die for a disc substrate, the molding die having: a fixed die member, a moving die member having a ring-shaped groove formed by a moving side mirror and an interlock ring which is fitted to an outside of the moving side mirror; an outer periphery ring disposed in opposition to an outer periphery portion of said fixed die member, the fixed die member being in opposition to the moving die member, the outer periphery ring being slidably disposed in an outer periphery portion of the moving die member or the fixed die member, a stamper being disposed in a cavity formed by the fixed die member, the moving die member, and the outer periphery ring, resin being injected into the cavity and solidified, wherein a low frictional resin ring with a substantially rectangular cross section is disposed in opposite clearances formed by the outer periphery surface of the outer periphery ring and an inner periphery surface of the interlock ring so that structurally the outer periphery ring is pressed from an outer periphery surface and at the same time can be smoothly slid in the ring-shaped groove, for the reason that, when resin is injected into the cavity, clearances A between the interlock ring and the outer periphery ring can be large and clearances B between an outer periphery surface of the moving side mirror and the outer periphery ring can be kept equal along the entire periphery of the outer periphery ring.