Preform production apparatus for precision press molding, producton method of a preform for precision press molding and production method of an optical element

Abstract

A preform production apparatus for precision press molding, which is downsized but can produce preforms at a lower cost, and a production method thereof using the apparatus are provided. The production method of a preform for precision press molding includes forming a molten glass body C by way of receiving and cutting molten glass A, being flowed continuously from a discharge nozzle 2 , by a support member 1 or by way of allowing molten glass to fall in drops from a discharge nozzle 2 and receiving thereof by a support member 1 , and transferring the molten glass body C from the support member 1 to a mold 5 by way of displacing the support member to near the mold 5 , disposed not to be beneath the discharge nozzle 2 , while increasing the viscosity of the molten glass body C on the support member 1.

1 - 12 . (canceled) 
     
     
         13 . A preform production apparatus for precision press molding, comprising;
 a discharge nozzle for discharging molten glass flow,   a support member for receiving molten glass discharged continuously or discontinuously from the discharge nozzle,   a mold for shaping a molten glass body, and   a displacing means for displacing the support member supporting the molten glass to be near the mold,   wherein the displacing means displaces the support member to be near the mold disposed to be not beneath the discharge nozzle, while increasing a viscosity of the molten glass body on the support member.   
     
     
         14 . The preform production apparatus for precision press molding according to  claim 13 , the displacing means has a glass body transfer auxiliary member disposed at a position disjunctive from the support member, and the molten glass body is transferred from the support member to the mold by the glass body transfer auxiliary member. 
     
     
         15 . The preform production apparatus for precision press molding according  claim 13 , the displacing means can displace the support member in three-dimensional directions, and the molten glass body is transferred by way of driving the displacing means. 
     
     
         16 . The preform production apparatus for precision press molding according to  claim 14 , a plurality of the support members is provided, the molten glass flow is received by each of the support members in series, and the displacing means transfers the molten glass body to the mold by way of displacing each of the support members, in which the number of the glass body transfer auxiliary members is less than the number of the support members. 
     
     
         17 . The preform production apparatus for precision press molding according  claim 16 , the number of the glass body auxiliary members is one. 
     
     
         18 . The preform production apparatus for precision press molding according to  claim 14 , the support member is configured to be openable and closable by way of a plurality of members, and the molten glass body is transferred from the support member to the mold through opening and closing the support member by way of contacting the glass body transfer auxiliary member with the support member. 
     
     
         19 . The preform production apparatus for precision press molding according  claim 14 , the support member is configured from one plate-like, rod-like or multiangular column-like member having a planar and/or curved surface, the molten glass body is transferred from the support member to the mold through inclination, deformation and/or rotation by way of contacting the glass body transfer auxiliary member with the support member. 
     
     
         20 . The preform production apparatus for precision press molding according to  claim 13 , log η is no less than 1.0 at the time when the molten glass body is displaced from the support member to the mold (η: viscosity of molten glass expressed by dPa·s, log: logarithm). 
     
     
         21 . The preform production apparatus for precision press molding according to  claim 13 , log η is less than 1.0 at the time when the molten glass is discharged from the discharge nozzle (η: viscosity of molten glass expressed by dPa·s, log: logarithm). 
     
     
         22 . The preform production apparatus for precision press molding according to  claim 13 , the support member floats the molten glass body by way of ejecting gas from at least a surface receiving the molten glass. 
     
     
         23 . The preform production apparatus for precision press molding according to  claim 13 , the mold floats the molten glass body by way of ejecting gas from at least a surface receiving the molten glass. 
     
     
         24 . An optical element-production apparatus performs precision press molding to a preform produced by the production apparatus according to  claim 13 . 
     
     
         25 . (canceled) 
     
     
         26 . An optical element-production apparatus, comprising;
 an apparatus for precision press molding that has a discharge nozzle for discharging molten glass flow,   a support member for receiving molten glass discharged continuously or discontinuously from a discharge nozzle,   a mold for molding a molten glass body, and   a displacing means for displacing the support member supporting the molten glass to be near the mold,   wherein the displacing means forms a molten glass body from the molten glass flow and displaces the support member to be near the mold, disposed to be not beneath the discharge nozzle, while increasing viscosity of the molten glass body on the support member.