Die and glass material for forming glass substrate, method for manufacturing glass substrate, and magnetic disk glass substrate

The present invention relates to a method for producing magnetic disk glass substrates suitable for recording media such as magnetic disks in large quantities and at a low price. A glass material () is placed in a forming die including a pair of upper and lower dies () and a control member () for co...

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Bibliographic Details
Main Authors Takagi, Kazuaki, Hibino, Kunio, Tokunaga, Tomokazu, Okuyama, Fujio, Onoda, Minoru
Format Patent
LanguageEnglish
Published 13.04.2004
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Summary:The present invention relates to a method for producing magnetic disk glass substrates suitable for recording media such as magnetic disks in large quantities and at a low price. A glass material () is placed in a forming die including a pair of upper and lower dies () and a control member () for controlling the space between the upper and the lower die, and then heated, softened, and molded by pressure into a glass substrate in the shape of a parallel plate. The amount of thermal contraction of the control member is smaller than that of the glass material. Therefore, the glass substrate is released from the die when cooled after molding. The present invention can provide a glass substrate that is excellent in smoothness and form accuracy of the surface, and that is suitable for recording media such as magnetic disks that are inexpensive and suitable for mass production.