PRODUCTION OF RAW MATERIAL FOR FORMATION OF OPTICAL ELEMENT

摘要

PROBLEM TO BE SOLVED: To provide a producing method of a glass block as the forming material of an optical element of high quality without producing striae or the like by which natural separation and cut can be surely performed, and preferably to more surly realize the separation and cut in a rather simple structure. SOLUTION: The flow of fused glass 2 flowing from a fused glass exit is accepted on an accepting face of a porous die 4 where gas is emitted in the state that the glass floats and maintains a non-contact state by the gas so as to obtain a fused glass block of a desired weight as the raw material to form an optical element. In this process, the die structure is designed in such a manner that the excess gas flow in the gas flowing out of the accepting face of the porous die which does not contribute to floating of the fused glass block 3 is not emitted in the direction to the exit of the fused glass flow.