Cylindrical Lens needs to meet what requirements to be considered qualified

There are many types of Lens, and Cylindrical Lens is one of them, which can change the direction of light propagation. It is widely used in lenses, prisms, etc. of optical instruments. Cylindrical Lens must meet the requirements of light imaging. It is no better than ordinary glass and has high requirements on the quality of Cylindrical Lens. Qualified Cylindrical Lens needs to meet the following requirements.

   First of all, the optical constants of Cylindrical Lens and the same batch of glass optical constants must be consistent. The first type of Cylindrical Lens has specified standard refractive index values ​​for different wavelengths of light, as the basis for optical designers to design optical systems.

   Therefore, the optical constants of the Cylindrical Lens produced by the factory must be within a certain allowable deviation range of these values, otherwise the actual imaging quality will not match the expected result during the design and the quality of the optical instrument will be affected. At the same time, because the same batch of instruments are often made of the same batch of Cylindrical Lens, in order to facilitate the unified calibration of the instruments, the allowable deviation of the refractive index of the same batch of glasses is more stringent than their deviation from the standard value.

   Secondly, it needs to have a high degree of transparency, and the image brightness of the optical system is proportional to the glass transparency. The transparency of Cylindrical Lens to light of a certain wavelength is expressed by the light absorption coefficient Kλ. After the light passes through a series of prisms and lenses, part of its energy is lost by the interface reflection of the optical parts and the other part is absorbed by the medium (glass) itself. The former increases with the increase of the refractive index of the glass. For high-refractive-index glass, this value is very large. For example, the light reflection loss on a surface of heavy flint glass is about 6%.