The function of optical thin film

Speaking of the function of optical lens film, we use the optical thin film of astronomical telescope as the following functions.

1, reduce the reflection function such as 400-700nm, the average reflectivity is less than 0.5% of the broadband antireflective film, we generally do 0.3-0.4%. With the continuous development of thin film technology and the improvement of the deep research and detection methods of thin film, the average reflectivity of the broadband antireflective film has reached 0.2%-0.3%, some even below 0.2%. The lower the reflectivity, the better the color and brightness of the telescope.

2, the protective functions such as ZF7, ZF13, ZK9 and other materials, soft and poor chemical stability, are easy to react with the oxygen and moisture in the air. The coating is isolated from the air after coating, and the chemical stability of the coated medium is good and the mechanical strength is high, so the lens can be protected by thin film, and it is not easy to produce imprint, nor is it easy to produce imprint. Easy to be scratched.

3. Special functions such as waterproof anti fog film, laser protective film and so on. After the lens is coated with waterproof and antifogging film, it can increase the hydrophobicity angle between the water beads and the lenses. When the lens tilts, the water drops because of the gravity traction. At present, the film material is soft, and the film is easy to wipe after the film formation, and the visible light is about 0.1% more than the broadband antireflective film. The laser protective film has a high reflective film of visible light (560NM), which can effectively prevent the penetrating laser from passing through; and the military laser protective film, such as 906NM, 1080NM reflectivity greater than 99.9% laser protective film, can effectively prevent the 906NM, 1080NM laser from passing through, and prevent the human eye from being burned by laser.