Chemical coating method: 70 years ago, coating method based largely on chemical reactions. This method must strictly control the concentration of chemical solution, a combination of cross-linking agent, reaction time and conditions. Because, only batch production, quality and yield obtained, the Senate defect missing. Commonly used processing method: a method for the dip, and the other was spraying method. For dipping method is based on the configuration properties of the membrane preparation containing components of the solution, and then the glass heated to a certain temperature, good chemical solution into the configuration, the out, drying, dip coating method can only produce two-mask the method. But then some of the lens design does not require double mask. Therefore, the other side must be washed, increased costs and environmental burden. Another deposition method, the solution is to configure a good film mounted on the gun, Zinc oxide spray the surface of the glass, drying, and stereotypes. Glass carrier can be moved or rotated in order to increase film uniformity. Can be plated double-sided or single-sided. Extension of this method of students there is a rejection gel method. Drops of the solution to the lens center, high-speed rotation of the lens using centrifugal force, the solution is even "throw" on the surface. To the present point of view, the benefits of chemical coating, in its investment in equipment is low, so it is still a common organic film coating and low-cost method.
Physical coating method: chemical preparation with a low price, the advantages of easy operation, but also the relative pollution, not the shortcomings of multi-layer coating. Shift to a new generation of physically coating technology to vacuum evaporation, ion plating and other different forms. Physically strength and uniformity of coating is generally higher than chemical coating, chemical coating layers with less physical methods to the more (because of multi-layer coating, the temperature and chemistry will affect the physical properties of the upper membrane).
In order to meet the requirements of photography, the lens is often necessary to modern multi-layer coated on the film. Different functions of these membranes can be broadly divided into seven categories: antireflective film, reflective film, filter membrane, polarized film, protective film and the electric membrane. The modern multi-layer technology can be broadly traced back to 1971 by Asahi (PENTAX) Optics developed SMC (super multi-layer) technology, in 1971, the application of this technology Takumar lenses in many large photography exhibition limelight. Nikon was already a three-layer coating technology, Titanium dioxide coating technology in more than five theoretically feasible. Japan's Canon and German Leitz (Leica's predecessor) is also similar to the positive development of coating technology, but the limit of 7-layer coating is still very difficult to break through the bottleneck! The other hand, FujiFilm claimed they developed EBC coating e-beam (electron-beam coating) claims up to 11 layers! until Asahi (PENTAX) published shortly after the SMC technology, FujiFILM will soon EBC coating technology into the manufacture of photographic lenses.
Asahi's main sources of technology purchased from OCLI (Optical Coatings Laboratories Inc.), Then they modeled the multi-layer coating technology, improve and develop its own technology and the cost control within the acceptable range. SMC as a turning point in photographic optics, which allows the development of modern wide-angle lens and ultra-long zoom lens possible. Asahi technological breakthroughs, Magnesia so many of the major camera manufacturers, including Canon, Nikon and Zeiss have to pay licensing fees to use some or all of the Asahi technology. Asahi's success, so that multi-layer lens has a new name change: In the past, SC, said single-layer coating, TLC for the double, SMC PENTAX technology for the multi-layer, then there are multi-layer translucent membrane MC and SSC development. EBC has been used as Fuji is its trademark.
From the coating history, despite SMC's technology is very attractive, but consider the maturity of less than Leica, has not been hastily put. In fact, according to Maurizio Micci Fotografare 1974, written by the magazine - a comparison test lens flare, can be found in Super-Takumar> MC Takumar> EBC Fujinon glare evaluation, in fact, only the SMC Takumars score higher than Super-Takumars a little bit. So you can understand the LEICA consideration is not without reason. Since 1972, LEICA has been committed to reducing the field of optical lenses and other studies to suppress the glare until 1978 suddenly changed its original position began to use multi-layer coating technology. To 1981, and Fuji, as the development of a new generation of electron beam coating technology, otherwise known as a hard coating. (Japan Fuji EBC reflect light poorly, also launched in 1981, Super EBC improved technology, still in use). Source: