Press mold for glass substrate and method for pressing glass substrate

Abstract

A press mold for glass substrate includes an upper mold and a lower mold, and a pressure apparatus for applying pressure to the upper mold and the lower mold, for molding a plate-shaped glass substrate having a predetermined thickness between the upper mold and the lower mold. An engaging projected piece is projectingly provided on the side portion of the upper mold, an engaging projected piece supporting portion for supporting the engaging projected piece is provided on the side portion of the lower mold, and an end portion of the upper mold is formed so as to be released from the lower mold with the engaging projected piece as a rotating shaft. Variance in pressure on mold surfaces between the upper mold and lower mold is detected, and a buffer made of material having lower compressive yield strength than material constituting the lower mold is inserted between the lower mold and the pressure apparatus in a position corresponding to the mold surface portion at lower pressure. It is possible to prevent the molded object or the mold from being damaged, and to apply uniform pressure on an entire mold surface by eliminating pressure variance on the mold surface of the mold as far as possible, and therefore, a large glass substrate molded object of excellent quality can be molded.

What is claimed is:  
     
         1 . A press mold for glass substrate, comprising an upper mold and a lower mold, and pressure means for applying pressure to said upper mold and said lower mold, for molding a plate-shaped glass substrate having a predetermined thickness between said upper mold and said lower mold, wherein an engaging projected piece is projectingly provided on a side portion of said upper mold, an engaging projected piece supporting portion for supporting said engaging projected piece is provided on a side portion of said lower mold, and an end portion of said upper mold is formed so as to be released from said lower mold with said engaging projected piece as a rotating shaft.  
     
     
         2 . The press mold for glass substrate according to    claim 1   , wherein 
 said pressure member is arranged above said upper mold with a pressure intermediate plate interposed therebetween, and a central upper surface of said pressure intermediate plate is formed into a concave shape, and a spherical seat formed into such a convex shape as to correspond to the concave shape in said pressure intermediate plate is provided on a central lower surface of said pressure member.    
     
     
         3 . The press mold for glass substrate according to    claim 1   , further comprising means for blowing air between said upper mold and said lower mold, on the side of said mold, which blows air between said upper mold and said lower mold after press molding.  
     
     
         4 . A pressing method for glass substrate for molding a plate-shaped glass substrate having a predetermined thickness between an upper mold and a lower mold by applying pressure to said upper mold and said lower mold through pressure means, said pressing method for glass substrate being characterized in that variance in pressure on mold surfaces between said upper mold and said lower mold is detected, and that a buffer made of material having lower compressive yield strength than material constituting said lower mold is inserted between said lower mold and said pressure means in a position corresponding to the mold surface portion at lower pressure.  
     
     
         5 . The pressing method for glass substrate according to    claim 4   , wherein said lower mold is made of heat resisting steel or ultra high strength steel, and said buffer is made of stainless steel.