Glass lenses have more scratch resistance than lenses of other materials, but their relative weight is also heavy, and their refractive index is relatively high: ordinary sheets are 1.523 (light white, gray, tea), ultra-thin sheets are: 1.7 (red, white), 1.8 (red, white, purple), 1.9 (red, white) up to 2.0, but the highest refractive index currently used for spectacle lenses is 1.9.
The main raw material for glass lenses is optical glass. The refractive index is higher than that of the resin lens, so the glass lens is thinner than the resin lens in the same degree. The glass lens has good light transmittance and mechanochemical properties, and has a constant refractive index and stable physical and chemical properties. The lens with no color is called a clear optical lens, the pink piece in the colored film is called a Cruxite optical lens, which is light purple in the incandescent lamp, and the light blue in the fluorescent lamp. Lens (Croo
Kes optical lens), the lens can absorb ultraviolet light, slightly absorb the strong light. There are only one manufacturer in China at present.
The glass sheet is superior in optical properties, is not easy to scratch, and has a high refractive index. The higher the refractive index, the thinner the lens. However, the glass piece is fragile and the material is heavy. When selecting the frame, you should try to choose a smaller frame, which can reduce the weight of the lens and ensure the wearing comfort.