The surface of the optical film is smooth and the interface between the films is geometrically divided; The refractive index of the film layer can jump at the interface, but it is continuous in the film layer; It may be a transparent medium or an absorbing medium; It may be normal uniform or non-uniform.

The practical film is much more complicated than the ideal film. This is because the optical and physical properties of the thin film deviate from the bulk material during preparation, and its surface and interface are rough, resulting in diffuse scattering of the light beam; The diffusion interface is formed by the mutual penetration between the film layers; Due to the growth, structure and stress of the film, the anisotropy of the film is formed; The film has complex time effect.

Optical thin films are divided into reflective films, antireflective films, filter films, optical protective films, polarizing films, spectroscopic films and phase films according to their applications. The first four types are commonly used. Optical reflective film is used to increase the specular reflectivity, and is often used to manufacture reflective, refractive and resonant cavity devices.

The optical antireflection film is deposited on the surface of the optical element to reduce the surface reflection and increase the transmission of the optical system, also known as the antireflection film. Optical filter film is used for spectral or other optical segmentation. It has many kinds and complex structure. The optical protective film is deposited on the surface of metal or other soft and erodible materials or films to increase their strength or stability and improve their optical properties. The most common is the protective film of the metal mirror.

The application of optical film is everywhere, from the coating of glasses to the liquid crystal display of mobile phones, computers, televisions to LED lighting, etc. it fills all aspects of our life and makes our life more colorful.

Usually, the preparation conditions of optical thin films are high and precise, and sometimes it needs to be carefully designed and analyzed. There is a very powerful software that can "take all" in the design and analysis of optical films. This TFCalc optical thin film software can be used to design various types of film systems such as antireflection, high reflection, bandpass, spectroscopic and phase.

Firstly, it supports the modeling of various membrane systems. TFCalc can design the double-sided film system of the substrate, and the maximum number of single facial mask layers can reach 5000, which supports the input of the film stack formula. And can simulate various types of light: such as cone beam, random radiation beam, etc.

Secondly, it has a certain optimization function. The reflectivity, transmittance, absorptivity, phase and ellipsometry parameters of the film system can be optimized by extreme value and variational methods. Needle method can also be used, as long as the initial single-layer film can automatically design various film systems.