Why the lens and lens need coating? This is because any object has a reflection on the role of light, even colorless transparent glass is no exception, the difference lies in the angle of light will form a reflection effect. For the ideal state of the lens, the light through the lens can be completely and correctly in the film or CCD is completely focused. However, the fact is that each of their lenses are subject to physical constraints, resulting in the generation of aberration. Therefore, the number of "problem" of the combination of camera lens is theoretically impossible to complete all the various angles of light pass through. Lanthanum Zinc oxide optical glass as an example, the transmission rate can reach 90%, and the remaining 10% will be reflected off the formation of glare. To compensate for this loss, the researchers developed a subsequent lens surface coated with a layer of the lens membrane to increase the light effect.

Although in the 1950s, designers can reduce glare coating to know the incidence, but also can enhance the image contrast and reduce the photo-blooming. But because of no appropriate processing technology. Therefore, Titanium dioxide the optical lens coating has always been only the highest level of the camera lens was entitled to the honor. Until 1968, a new generation of coating technology was developed to allow cheap coating process and the implementation of standards can only make the increasingly popular with the lens coating. In 1970 as a watershed in the development of coating technology, we can understand the technical differences before and after.

By the 1970s, 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, 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. Magnesia 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.

Chemical preparation has a low price, the advantages of easy operation, Nickel oxide but the pollution is relatively large, 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).

Generally speaking, the lens surface of the coating layer itself is colorless and transparent. Not only through the lens of the light will be reflected back to form a human eye can see the reflection. The more light through the lens, reflector is weaker. Uncoated lens, its relatively low transmittance of the lens, the lens surface of the more serious reflection on the spectrum have a strong reflection of light, so the overall color is white reflective. SC single coated lens, the lens of the reflective surface is weak, greatly increasing the spectral transmittance of the central yellow green, only red and blue ends of the spectrum was only reflection, the general was so reflective blue purple. SMC multi-coated lens, the lens is very high light transmittance, a direct reflection of the lens surface is weak, Neodymium fluoride you need to cover the end of the lens cover, backlit glass lens opposite view, observed from the side of the lens can see the color reflective, this reflective coating according to the characteristics of different manufacturers can be divided into dark red (AR Blu-ray), blue (AR red), dark yellow (by transparent blue-green) and dark green and so on. Dark green coating which can increase the spectrum of blue and red ends of the transmission, only the central part of the spectrum was only yellow-green light reflected back, so the antireflective film of the transmittance curve of a red and blue an increase in the peak and effective along the wide color gamut. Consider that if all the lenses are antireflection coated with the same membrane, bound to occur if the lens color cast. Therefore, each different camera lenses, the lens must be based on the materials used and the extent of absorption of different shade, were coated with antireflection coatings with different characteristics, each with up to make the lens to increase the total light transmittance, and The transmittance of the lens shade can reach equilibrium.

Maintenance coating

In general, the outermost layer of the coated lens is usually the dura mater, to protect the general's hand touch or clean the lens will not cause harm to them. This point, whether it is a traditional SLR camera or digital camera lens consumer alike. Although, this layer of film has a protective effect, but in fact its thickness may be only 0.1 nm, the friction is too strong, or will damage this layer of film formation, Barium titanate thereby affecting the shooting. Therefore, multilayer lens cleaning method, there are several points to note.

Cleaning fluid selection: general use of anhydrous alcohol or ether (or a mixture of both) - (Note: ether for the toxic chemicals). If you must clean up with water, you need to find water or deionized water, or leave the water classes.

Clean cloth choices: You can use cotton, the most simple and cheapest. If the fiber left off, with the balloon can be blown off. Generally have a special camera lens shop selling paper, Qiang deerskin, non-woven like cleaning supplies. Leather or cloth products, as little as possible. Because these things can be reused when the air in a very small or hard sand deposition in the above, the film will use scratch again.

If the lens is coated with the fingerprints, grease or mildew caused by improperly stored, using the above method can not be clean. Best to get the camera shop, the use of ultrasonic cleaning method to clean. Do not use strong acid cleaning solution (such as: glass magic spirit), although the outermost layer of the cuticle can be acid, but thin and limited capacity.

Once the cuticle is damaged, the light, you can see some of the irregular, rainbow-like reflections. This can be used as a reference when buying second-hand lens indicators. Source:www.mhcocm.com