Anti-fog lens cloth is actually a chemical composition. Take electric heated anti-fog mirrors as an example. The principle is that the humidity of the mirror surface is increased through electric heating, and the fog quickly evaporates, so that no fog layer is formed.
1. The fog on the lens is the tiny water droplets formed by the condensation of water vapor in the air on the lens surface at low temperatures. There are two conditions for the formation of fog: there is moisture in the air, and the temperature of the water vapor is higher than the temperature on the lens.
2. To prevent fogging of lenses, there are three main methods:
(1) Mechanical removal - similar to car window wipers.
Install a wiper on the glasses. This method removes fog mechanically, which is unsightly, heavy, and very unrealistic;
(2) Reduce the temperature difference and avoid contact with the lenses. Humid air with high surface temperature may preheat the lens surface temperature to even higher than the new ambient temperature.
It is usually necessary to place the glasses in a new, possibly foggy environment, so that the lens temperature is consistent with the ambient temperature (cold wind blowing through car windows to defogging) or higher than the temperature of the air (car windows) Blow hot air to remove fog), or avoid the steam environment entirely. This method is to destroy the conditions for fog formation. Such a solution is contact lenses, without which normal use of glasses is almost impossible.
(3) Reduce the surface tension of the fog beads so that all the fog beads on the lens are flattened to form an ultra-thin water film that does not interfere with vision.
The most realistic method is to turn the fog beads on the lenses into a water film that does not interfere with vision. There is currently a special anti-fog lens on the market, which is coated with a special anti-fog film layer, which can effectively reduce the chance of fog generation. When used with a special anti-fog cleaner, the outer surface of the lens can remain relatively firmly anti-fog. Cleaner to achieve long-lasting lens anti-fogging for up to 7 days. ?
There are two reasons for lens fogging:
First, the liquefaction phenomenon occurs when the hotter gas in the lens meets the colder lens.
The second is that the water on the skin surface sealed by the glasses evaporates and the gas condenses on the lenses. This is also the main reason why spraying anti-fog agent does not work. A kind of anti-fog glasses designed using the electromagnet principle. The wiping strip is controlled by an electronic timing key that can adjust the wiping frequency through the electromagnet. It can be used for swimming, skiing, mountain climbing, diving, medical care (the anti-fog problem of eye masks during SARS brought a lot of inconvenience to medical workers), labor insurance, scientific research and biochemistry, helmets, space suits, optical instruments, etc.