There are many kinds of glass, optical glass is one of them, it is able to change the direction of light propagation. It is widely used in optical instruments, such as lenses, prism, etc.. Optical glass, it must meet the requirements of the light, it is not more than the general glass, the quality of the optical glass is also very high. Qualified optical glass it needs to meet the following requirements.

First of all, optical constants of optical glass and optical constants of the same batch of glass should be the same, the first type optical glass of different wavelengths of light have the provisions of the standard index of refraction, as a basis for optical designers in the design of optical system.

So the optical constants of factories for the production of optical glass must be in the numerical values of certain allowable deviation range within, otherwise it will make the actual as design quality and expected results inconsistent and affect the quality of optical instruments. At the same time, because the same batch of instruments are often used in the same batch of optical glass manufacturing, in order to facilitate the uniform calibration of the instrument, the deviation of the refractive index of the same batch of glass is more strict than their standard deviation.

Secondly, it needs to have a high degree of transparency, the brightness of the optical system into the image and the transparency of the glass into a proportional relationship. Optical glass to a certain wavelength of light transparency in the light absorption coefficient K. Light passes through a series of lenses and lenses, whose energy is partially absorbed by the interface of the optical part and the other part is absorbed by the medium (glass). The former with glass refraction rate increases, the high refractive rate of glass this value is very large, such as the heavy flint glass surface optical reflection loss of about 6%.