FORMING DEVICE FOR OPTICAL GLASS

摘要

PROBLEM TO BE SOLVED: To form glass formed articles having extremely good surface accuracy by forming many uniaxially directional micropores opening over the entire surface of the mold surface of a formed mold in such a manner as to nearly uniformly disperse these pores and executing forming of a glass gob while supplying gas to the respective pores from the lower side of this mold surface. SOLUTION: The forming mold 7 for forming the molten glass which flows down from a nozzle tip 1 and is disconnected therefrom to a desired shape is provided with a multiplicity of the uniaxially directional micropores 9. The pores 9 penetrate the forming mold 7 toward a vertical direction and the pore diameter thereof is below 200μm. The pores are so formed as be nearly uniformly distributed over the entire part of the mold surface 7a and the sum of the cross-sectional area per 1 cm2 specified to >=0.5 mm2. In addition, the rear surface 7b is formed as a projecting curvilinear shape so as to correspond to the recessed curvilinear shape at the mold surface 7a of the forming mold 7. Gaseous nitrogen is supplied from the rear surface side of the forming mold 7 and a gas cushion layer is formed between the mold surface 7a and the glass gob.