（Scoreboard gun aiming manufacturer） Optical glass is made of high-purity silicon, boron, sodium, potassium, zinc, lead, magnesium, calcium, barium and other oxides mixed according to a specific formula, melted in platinum crucible at high temperature, stirred evenly by ultrasonic wave to remove bubbles, and then cooled slowly for a long time to avoid inner edge of glass block. The cooled glass block must be measured by optical instruments to check whether the purity, transparency, uniformity, refractive index and dispersion index meet the specifications.
