Glass substrate forming mold and production method for glass substrate
First Claim
1. A glass substrate forming die for manufacturing a glass substrate in a shape of a parallel plate, comprising:
- a pair of upper and lower dies, and a control member for controlling a space between the upper and lower dies, wherein a coefficient of thermal expansion of the control member is smaller than a coefficient of thermal expansion of a material used for the glass substrate.
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Abstract
A glass material (4) is placed in a forming die including a pair of upper and lower dies (1, 2) and a control member (3) 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.
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Citations
17 Claims
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1. A glass substrate forming die for manufacturing a glass substrate in a shape of a parallel plate, comprising:
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a pair of upper and lower dies, and a control member for controlling a space between the upper and lower dies, wherein a coefficient of thermal expansion of the control member is smaller than a coefficient of thermal expansion of a material used for the glass substrate. - View Dependent Claims (2, 3, 4, 5)
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6. A method for manufacturing a glass substrate comprising:
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placing a glass material in a forming die including a pair of upper and lower dies and a control member for controlling a space between the upper and lower dies;
molding the glass material into a glass substrate in a shape of a parallel plate by pressure, wherein a coefficient of thermal expansion of the control member is smaller than a coefficient of thermal expansion of the glass material, and the glass material comes into point-contact with the forming die when placed therein, and as a contact portion between the glass material and the forming die is increased by pressure molding, the glass material is transformed continuously so as to prevent air from entering the contact portion. - View Dependent Claims (7, 12, 13, 14, 15)
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8. A method for manufacturing a glass substrate comprising:
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a first step of placing a glass material in a forming die including a pair of upper and lower dies and a control member for controlling a space between the upper and lower dies;
a second step of heating and softening the glass material;
a third step of molding the glass material into a glass substrate in a shape of a parallel plate by pressure;
a fourth step of cooling the glass substrate; and
a fifth step of taking out the glass substrate, wherein a coefficient of thermal expansion of the control member is smaller than a coefficient of thermal expansion of the glass material. - View Dependent Claims (9)
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10. A method for manufacturing a glass substrate comprising:
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a first step of placing a glass material on a saucer;
a second step of heating and softening the glass material;
a third step of placing the glass material, which rests on the saucer, in a forming die including a pair of upper and lower dies and a control member for controlling a space between the upper and lower dies;
a fourth step of molding the glass material into a glass substrate in a shape of a parallel plate by pressure;
a fifth step of cooling the glass substrate; and
a sixth step of taking out the glass substrate, wherein a coefficient of thermal expansion of the control member is smaller than a coefficient of thermal expansion of the glass material. - View Dependent Claims (11, 16, 17)
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Specification