Mold component and mold assembly

A mold assembly for defining a cavity for molding a substrate for an optical recording medium, comprising:

• a first mold having a mounting portion;
• a second mold which closes together with said first mold to thereby define a cavity between said first mold and said second mold;
• a stamper having a molding surface configured to form micro asperities in a surface of the substrate for the optical recording medium;
• and
• a stamper holder configured to hold said stamper thereon, said stamper holder having a generally hollow cylindrical shape such that said stamper holder can be mounted to said mounting portion of said first mold,
• wherein said stamper has an insertion hole extending through a central portion thereof, the insertion hole having a diameter which is larger than an outer diameter of a cavity-side end of said stamper holder when said stamper is at a higher temperature than a normal temperature, and the insertion hole diameter being smaller than the outer diameter of the cavity-side end of said stamper holder when said stamper is at a normal temperature and is not held on the stamper holder, said stamper being held on said stamper holder, with the cavity-side end of said stamper holder being grasped by a rim of the insertion hole which has the smaller diameter when the stamper is at the normal temperature, after having the cavity-side end of said stamper holder inserted therein when the stamper is at the higher temperature.

A mold assembly, comprising:

• a stamper configured to mold a surface of a substrate for an optical recording medium, said stamper having an insertion hole;
• and
• a stamper holder, said stamper holder including a holding portion inserted within the insertion hole, wherein said stamper is secured to the holding portion of said stamper holder by heat shrinkage,
• wherein a height of the holding portion is less than a height of the stamper.