The production and manufacture of filter technology is a complex engineering technology, involving a lot of professional technical fields, including vacuum acquisition technology, Zhenlong measurement technology, computer-aided design technology, optical characteristics detection technology, electronic circuit technology, material characteristics detection and preparation technology.
Optical filter is the characteristic of changing the transmission of light wave by coating one or more dielectric or metal films on optical elements or independent substrates. The characteristics of light waves in these thin films are used, such as transmission, absorption, scattering, reflection, polarization, phase change, etc., and then various filter products are designed and manufactured to achieve the application purpose of science and engineering.
Filter function: the filter has a great effect and is widely used in the photography field. Why are the main scenes always so prominent in some landscape paintings taken by the master? It is because of the use of filters. For example, if you want to take a yellow flower, the background is blue sky and green leaves. If you take photos as usual, you can't highlight the theme of "yellow flower", because the image of yellow flower is not prominent enough.
However, if a yellow filter is installed in front of the lens, blocking the green light from a part of green leaves and blue light from blue sky, and allowing the yellow light from yellow flowers to pass through a large amount, so that the yellow flower is very obvious, highlighting the theme of "yellow flower".
Filter principle: optical filter is made of plastic or glass and special dyes. Red filter can only let red light pass through, and so on. The refractive index of glass sheet is similar to that of air. All color light can pass through, so it is transparent. However, after dye is dyed, the molecular structure changes, refractive index changes, and the passing of some color light changes. For example, a white light passes through a blue filter, and it emits a blue light, while green light and red light are very few, most of which are absorbed by the filter.