Patent ID: 6227008
Filing Date: 2001-05-08
Classification: C03B

Abstract:
Apparatus for forming a heated glass sheet having a periphery, comprising:a vacuum mold having a full surface that defines a shape to which the glass sheet is to be formed;a peripheral mold for forming and sealing the periphery of the glass sheet against the surface of the vacuum mold to provide a sealed periphery of the glass sheet; anda vacuum system including at least one vacuum reservoir, conduiting including at least one conduit for communicating the vacuum reservoir and the vacuum mold within the sealed periphery of the glass sheet, and valving including at least one valve located between the vacuum reservoir and the vacuum mold and operable to: (a) initially communicate the vacuum mold surface within the sealed periphery of the glass sheet with the vacuum reservoir to provide a vacuum impulse in the range of 0.1 to 0.7 atmospheres of vacuum to elastically form the glass sheet to the shape of the vacuum mold surface; and (b) thereafter terminate the vacuum impulse at a predetermined time so as to reduce optical distortion of the heated glass sheet as a result of engagement with the vacuum mold surface.