| 摘要 |
PURPOSE:To improve the transferability and optical characteristics in particularly the outer peripheral region of the substrate for an optical disk medium by constituting molds for injection molding in such a manner that the gases in the cavity of the molds are smoothly and uniformly discharged. CONSTITUTION:A stamper 1 is fixed by an outer peripheral ring 4 to the base of the stamper side mold A and the counter mold B is fitted to the mold. A molten resin is filled into the cavity between the two molds A and B and the substrate for the optical disk medium is injection-molded. Of the outer peripheral ring 4 and the stamper side mold A, at least on the outer peripheral ring 4, discharge holes 19 communicating with the inside of the cavity is radially formed. These respective discharge holes 19 are communicated with the outdoor air. Or, the holes are connected with piping to a discharge pump P. |
