Optical glass has high transparency, purity, colorlessness, uniform texture, and good refractive power, so it is the main raw material for lens production. Due to the different chemical composition and refractive index, optical glass has:

1. Flint Glass - Add lead oxide to the glass composition to increase the refractive index (1.8804)

2. bismuth glass - made by adding sodium oxide and calcium oxide to the glass component to reduce its refractive index (the refractive index of bismuth glass is 1.7055)

3. Antimony glass - for the varieties found, it has excellent refractive index and low dispersion rate, which provides conditions for creating large-caliber advanced lenses.