Press molding apparatus and method of producing a glass optical element using the apparatus

Abstract

In a press molding apparatus for press molding a plurality of glass materials into a plurality of glass optical elements by the use of a pressing mold including upper and lower molds each of which has a plurality of molding surfaces, at least one of the upper and the lower molds is a heat generator within which heat is generated when the heat generator is subjected to a high-frequency induction heating by an induction heating coil. The heat generator having a plurality of shape-processed portions ( 130 ) produced by partially processing a shape of the heat generator in order that a temperature distribution of the heat generator is adjusted. The apparatus simultaneously press forms, into the glass optical elements, the glass materials supplied between the molding surfaces of the upper and the lower molds which are subjected to the high-frequency induction heating.

1 . A method of manufacturing a glass optical element by use of a pressing mold comprising upper and lower molds each of which comprises a molding surface, at least one of said upper and lower molds comprising a heat generator within which heat is generated when said heat generator is subjected to high-frequency induction heating, said heat generator comprising a shape-processed portion produced by processing a shape of said heat generator in order that a temperature distribution of said heat generator is adjusted when said heat generator is subjected to high-frequency induction heating, comprising the steps of: 
 subjecting at least one of said upper and said lower molds to said high-frequency induction heating so that the molding surfaces of said upper mold and said lower mold have predetermined temperatures; and    press molding said glass material supplied between said molding surfaces of said upper and said lower molds into said glass optical element.    
   
   
       2 . The method of  claim 1  wherein said shape-processed portion comprises at least one of a perforation, cutout, curved surface, and obtuse angle.  
   
   
       3 . The method of  claim 2  wherein each of said upper and lower molds comprises a plurality of molding surfaces so that a plurality of said glass materials be press molded simultaneously.  
   
   
       4 . The method of  claim 3  wherein said shape-processed portion is located so that temperature of each molding surface on the upper mold or the lower mold be brought closer.  
   
   
       5 . The method of  claim 4  wherein said each of said upper and lower molds has a shape extended in a direction, said molding surfaces being arranged in the direction.  
   
   
       6 . A method of manufacturing a glass optical element comprising: 
 preparing a pressing mold comprising upper and lower molds each of which comprises a molding surface, at least one of said upper and lower mold comprising a heat generator within which heat is generated when said heat generator is subjected to high-frequency induction heating,    processing a shape of said heat generator so that a temperature distribution of said heat generator is adjusted when said heat generator is subjected to high-frequency induction heating,    subjecting at least one of said upper and said lower molds to said high-frequency induction heating so that each of the molding surfaces of said upper mold and said lower mold have predetermined temperature; and    press molding a glass material supplied between said molding surfaces of said upper and said lower molds into said glass optical element.    
   
   
       7 . The method of  claim 6  wherein a shape-processed portion formed by said processing comprises at least one of a perforation, cutout, curved surface, and obtuse angle.  
   
   
       8 . The method of  claim 6  wherein each of said upper and lower molds comprises a plurality of molding surfaces so that a plurality of said glass materials be press molded simultaneously.  
   
   
       9 . The method of  claim 8  wherein a shape-processed portion formed by said processing is located so that temperature of each molding surface on the upper mold or the lower mold brought closer.  
   
   
       10 . The method of  claim 6  wherein each of said upper and lower molds comprises a plurality of molding surfaces, 
 which method further comprises, prior to said processing, measuring a temperature distribution of molding surfaces on upper or lower mold when said heat generator is subjected to high-frequency induction heating to observe a temperature deviation of said molding surfaces from each other, and said processing is carried out so that said deviation is reduced.    
   
   
       11 . The method according to  claim 1 , wherein said glass material is are heated to a preselected temperatures to be softened before said glass material are supplied between the molding surfaces of said upper and said lower molds.  
   
   
       12 . The method according to  claim 11  wherein said preselected temperature is higher than the temperatures of the molding surface of said upper and said lower molds when said glass materials are supplied between the molding surfaces of said upper and said lower molds.  
   
   
       13 . The method according to  claim 12 , wherein said glass materials are heated to the preselected temperature to be softened so that said glass materials have a viscosity not higher than 10 9  poises.  
   
   
       14 . The method according to  claim 1 , further comprising the steps of: 
 preparing a pressing mold set comprising a plurality of said pressing molds which are arranged so that the molding surfaces of the upper molds of said pressing molds are aligned in an upper single line and that the molding surfaces of the lower molds of said pressing mold are aligned in a lower single line parallel to said upper single line, each of the upper and the lower mold comprising the heat generator within which heat is generated when said heat generator is subjected to the high-frequency induction heating;    at least a pair of the adjacent heat generators of the upper molds or the lower molds comprises the shape processed portion comprising rounded corners formed on sides of the heat generators adjacent with each other.    
   
   
       15 . The method of  claim 14 , wherein said glass materials are heated to a preselected temperature to be softened before said glass material are supplied between the molding surfaces of said upper and said lower molds, said preselected temperature being higher than the temperatures of the molding surface of said upper and said lower molds when said glass materials are supplied between the molding surfaces of said upper and said lower molds.  
   
   
       16 . The method according to  claim 15 , wherein said glass materials are heated to the preselected temperature to be softened so that said glass materials have a viscosity not higher than 10 9  poises.  
   
   
       17 . A press molding apparatus for preparing a plurality of glass optical elements from a plurality of glass materials, comprising: 
 upper and lower molds each of which comprises a plurality of molding surfaces; and    an induction heating device for heating said upper and lower molds;    at least one of said upper and lower mold comprising a heat generator within which heat is generated when said heat generator is subjected to high-frequency induction heating by said induction heating device;    said heat generator comprising a shape-processed portion produced by processing a shape of said heat generator in order that a temperature distribution of said heat generator is adjusted when said heat generator is subjected to high-frequency induction heating.    
   
   
       18 . The apparatus according to  claim 17 , wherein said shape-processed portion comprises a rounded surface.  
   
   
       19 . The apparatus according to  claim 17 , wherein said shape-processed portion comprises an acute-angled shape.  
   
   
       20 . The apparatus according to  claim 17 , wherein said shape-processed portion comprises a knurled shape.  
   
   
       21 . The apparatus according to  claim 17 , wherein said shape-processed portion comprises a chamfered corner.  
   
   
       22 . The apparatus according to  claim 17 , wherein said shape-processed portion comprises an obtuse-angled corner.