Press molding apparatus and press molding method

Abstract

A press molding apparatus includes upper and lower mother molds 102 and 104 . Each of the mother molds 102 and 104 has four molding surfaces arranged in a single line and satisfies the relationship given by L×α×ΔT/t<0.0008, where L represents the length, t, the thickness, α, the thermal expansion coefficient, and ΔT, the temperature difference between both ends in the thickness direction during induction heating. The press molding apparatus may include a pressing mold set including upper mother molds 102 a and 102 b attached to a common fixed shaft 118 through upper supporting shafts 110 a and 110 b and lower mother molds 104 a and 104 b driven by a common drive shaft 120 through lower supporting shafts 112 a and 112 b . The upper mother molds 102 a and 102 b and the lower mother molds 104 a and 104 b are collectively heated by induction heating coils 122 and 124 , respectively.

1 . A press molding apparatus for simultaneously press molding a plurality of molding materials into a plurality of optical elements, comprising: 
 a plurality of upper mother molds and a plurality of a lower mother molds, each of said plurality of upper mother molds and lower mother molds comprising a plurality of upper molding surfaces and a plurality of lower molding surfaces, respectively,    a plurality of supporting shaft each of which supports each of the upper mother molds and each of the lower mother molds,    at least one heating coil which surrounds the plurality of upper mother molds collectively and the plurality of lower mother molds collectively, and a driving shaft which moves the upper mother molds or the lower mother molds so that the upper mother molds or the lower mother molds move towards and away from the others,    wherein the plurality of the upper supporting shafts or the plurality of the lower supporting shafts are commonly driven by said driving shaft.    
     
     
         2 . The apparatus of  claim 1  wherein said upper mother molds and said lower mother molds are disposed so that upper molding surfaces and the lower molding surfaces are aligned in a direction.  
     
     
         3 . The apparatus of  claim 1  wherein the heating coil comprises an induction heating coil.  
     
     
         4 . The apparatus of  claim 3  wherein and said upper mother molds and said lower mother molds each comprises round shaped portion on a side adjacent to each other.  
     
     
         5 . The press molding method for obtaining a plurality of optical elements by simultaneously press molding a plurality of materials, comprising: 
 supplying a molding materials into a press molding apparatus, and carrying out a pressing,    wherein said apparatus comprising    a plurality of upper mother molds and a plurality of a lower mother molds, each comprising a plurality of upper molding surfaces and a plurality of lower molding surfaces, respectively,    a plurality of supporting shaft each of which supports each of the upper mother molds and the lower mother molds,    at least one heating coil which surrounds the plurality of upper mother molds collectively and the plurality of lower mother molds collectively, and a driving shaft which moves the upper mother molds or the lower mother molds so that the upper mother molds or the lower mother molds move towards and away from the others,    whereby the plurality of the upper supporting shafts or the plurality of the lower supporting shafts are commonly driven by said driving shaft.    
     
     
         6 . The press molding method of  claim 5  wherein the molding materials are heated to a temperature higher than that of the upper and the lower mother molds and softened before the materials are supplied.  
     
     
         7 . The press molding method according to  claim 5  wherein the molding materials are glass materials which are heated to a temperature corresponding to the viscosity not higher than 109 poises before the materials are supplied.