What is hard coating on lenses?

In the previous article, we discussed “What are NXT Lenses?”. In this article, let’s talk about “Is LensCrafters expensive?”.

What is hard coating on lenses?

Lenses are mainly added in two kinds of film: anti-reflection film and hard film (and some manufacturers produce anti-fogging film and mirror film, but not common). The anti-reflective film is mainly by coating the front surface of the lens with multiple layers of transparent materials with different refractive index and thickness to reduce the excess reflected light on the surface of the lens, by using the principle of light interference. The film can be applied to both glass and resin lenses. The way of hard film plating is usually a soaking process. After many times of soaking and cleaning, soaking in an organic solution containing ultrafine silicon element for a certain time, and then keeping it at a certain temperature for 4-5 hours, the fixed polymerization process of the film has been completed. The surface wear resistance of CR-39 coating can be increased by 2-4 pH, which is similar to the hardness of optical glass lenses.

What effect does a lens with the hard film have?

In order to improve the wear resistance of the lens, it is necessary to coat the surface of the lens with hard film. At present, silicon atoms are used to stiffen the membrane, that is, the stiffening solution containing organic matrix and inorganic superfine particles including silicon element is used to make the hard film have toughness and hardness at the same time. Because the common resin lens is far easier to wear than the glass lens, so the addition of hard film is mainly used for resin lens. It is usually applied to the front surface of the lens, and the anti-wear ability of the resin lens with the film will be enhanced a lot, and the light permeability will be strengthened.

How to maintain a hard-coated lens?

The hard-coated resin lenses can be identified by the sound of the tabletop tapping and the color brightness of the lenses. The lenses, which sound clear and have bright edges, are hardened. In daily use, avoid overheating environment. Avoid contacting with alkaline liquid, so as not to cause damage to the lens. And this damage is usually not formed in an instant.

Long-term use, sun exposure, and so on may make the coating slowly fall off. If the production of hard film technology is worse, the film is easier to fall off. When cleaning and adding a hard-coated lens, clean the particles on the front and rear surfaces of the lens with clean water first, and then blot dry with a clean soft cloth. Do not wipe the surface when the lens is dry.