SPHERICAL GLASS MATERIAL ND METHOD FOR PRODUCING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a spherical glass material having high volume accuracy and prescribed optical performance and suitable for the press molding of an optical part at a low cost. SOLUTION: The spherical glass material is composed of an optical glass and has the deviation of diameter falling within the range of 1/50 to 1/5 relative to the diameter of true sphere calculated from the prescribed volume, the volume deviation of within±1% from the prescribed volume. The number of particles having a particle diameter of >=10μm and welded to 1 mm2 of the surface is <=1. The spherical glass material is produced by supplying the molten glass composed of the optical glass in the form of a glass droplet 3 having a volume deviation of±1% or less relative to the prescribed volume in a clean booth 10 maintained to the cleanliness of 7 or higher and forming the glass droplet 3 in the form of glass sphere 12.