Optical lenses are mixed with high purity silicon, boron, sodium, potassium, zinc, lead, magnesium, calcium, barium and other oxides according to a specific formula, melted in a platinum crucible at high temperature, stir evenly with ultrasonic, to bubble; The lenses are then cooled slowly for a long time to avoid internal stress. After cooling, the lenses must be measured by optical instruments to check whether the purity, transparency, uniformity, refractive index and dispersion rate meet the specifications.
