Film is very common in nature. For example, the bubble surface film, the surface of oil droplets will form a so-called thin-film optical effects, and it will separate light colors. In some biological species, there will be a special film structure formation. For example, the eyes of some nocturnal animals within the tapetum lucidum(such as dogs, sharks, cat). The wings of bee and dragonfly, is a thin film formation also.
There are two main optical thin film research, thin film optics and thin film deposition (or coating) technology. Thin-film optics is a branch of physical optics, the main structure of thin films of different materials, the effects of light. Human beings can see the thin film optics, mainly membrane film thickness reaches a certain thickness, the energy intensity of the visible spectrum of light, do different levels of interference resulting increase or decrease. This interference phenomenon is the refractive index of light through different materials (air, film, glass substrate) is generated.
Thin film optics is the light penetration between different materials (incident) when the interference phenomena. When the light through film, it features there are many changes. For example, transmittance, reflectance, absorption, scattering, polarization, phase and other changes. It is based on the physical theory of electromagnetic wave theory can be used to explain the interference phenomenon. By Maxwell's equations (Maxwell equation), Zinc oxide can explain the light passes through different materials, because the refractive index change for a variety of phenomena. As a full electromagnetic wave theory has to explain the basic theory of optical thin films, and therefore the current academic research, are placed on the application of thin film optics.
Design and manufacture of thin film changes the nature of the incident light, is the focus of this subject. Structural design in film theory, there are two common design approach, Novel Monitoring Method and Vector Method. In the absence of the computer age, because the admittance method can be calculated by way of mapping and pen and paper to complete the design, so in 1970, before the widespread use of the designer is generally the way. Vector method because of the need large-scale computing, before the invention of the computer is not difficult to apply in the actual design stage. Widespread use of computers and computing power increased dramatically, the vector method because it can provide more accurate results, so most designers use a vector-based method to write computer programs.
After World War II, as technology advances, Magnesia the optical film used in a lot of optoelectronic products. Such as interferometers, cameras, telescopes, microscopes, optical engine, monitors, projectors, optical communications, satellites, missiles, decorated .... and so on. Therefore, the optical film to become an important branch of optical discipline, you can find a lot of textbooks, to understand the relevant knowledge.
Deposition of optical thin film deposition technology, all technology is only a small part of the story, in addition to optical films, the films have different film deposition techniques can be applied to the field. For example: electromagnetic film, film mechanical properties, chemical film Titanium dioxide.... In particular, the semiconductor industry, the use of a large number of thin film deposition techniques to deposit a variety of different characteristics of different types of film, scattered terror in the semiconductor crystal growth, grain growth, grain aggregates, road fill the gap, film growth, etc., a variety of different process procedures . Because thin-film deposition technology, the scope is too broad to discuss here only the optical thin film deposition method.
Generated in the nature of the film, because it is too thin, difficult to capture direct human use. If people want to use thin-film effect, usually only use artificial methods to manufacture it. And must be generated in the application of its products directly, or use a substrate carrying thin film, the film simply can not do the first, then install the product above. Source: