How to judge the quality of optical glass?

        Optical glass refers to glass that can change the transmission direction of light and change the relative spectral distribution of ultraviolet, visible or infrared light. Optical glass in a narrow sense refers to colorless optical glass; optical glass can be used to make lenses, prisms, mirrors and windows in optical instruments. The difference between optical glass and other glasses is that as a component of an optical system, it requires optical imaging requirements. Therefore, the quality of optical glass also includes some stricter indicators.

        1. Specific optical constants and the sameness of optical constants of the same batch of glass

        Various types of optical glass have regular standard refractive index values for different wavelengths of light, which are used as the basis for optical planners to plan optical systems. Therefore, the optical constants of the optical glass produced by the factory need to be within the tolerance range of these values, otherwise the actual imaging quality will not match the expected results in planning and the quality of the optical instrument will be affected.

        2. Transparency

        The brightness of the image of the optical system is proportional to the transparency of the glass. The transparency of optical glass to light of a certain wavelength is represented by the light absorption coefficient Kλ. After the light passes through a series of prisms and lenses, some of its energy is lost to the interface reflection of the optical components and some is absorbed by the medium (glass) itself. Therefore, for an optical system containing multiple thin lenses, the main way to increase the transmittance is to reduce the reflection loss on the surface of the lens, such as coating the surface with an antireflection coating.