Physical properties:

　　1. Density: Density is the mass of 1cm3 material, and the unit is g/cm3. The oxide contained in the lens material determines the density of the lens material.

　　The density of different lens materials

　　2. Hardness: Glass is fragile, but very hard. Nevertheless, in the case of long-term use or without basic protection (glasses and hard objects contact), the original high-finish and completely transparent spectacle lenses will also be worn. A large number of small surface wear on the spectacle lens will cause the incident light to scatter, change the transmittance of the glass lens, and affect the image quality.

　　 For resin lenses, the hardness alone cannot evaluate its wear resistance. It is also necessary to comprehensively consider the elastic deformation of the lens material, the deformation of the plastic optical lens, and the material Molecule binding force, etc.

　　3. Impact resistance: The impact resistance reflects the ability of the lens material to resist the impact of hard objects under specified conditions. The relative impact resistance of various materials depends on factors such as the size and shape of the impact object.

　　Chemical properties: Chemical properties reflect the reaction characteristics of lens materials to chemical substances in lens manufacturing and daily life, or the reaction characteristics of materials under certain extreme conditions. Usually cold water, hot water, acids and various organic solvents.

　　 Generally, glass lens materials are not affected by various short-term accidental chemical products, but the following factors will corrode glass lens materials:

　　A. Hydrofluoric acid, phosphoric acid and their derivatives;

　　B. The high temperature water of the optical lens will make the surface of the smooth lens rough;

　　C. The surface of the lens will be corroded under humidity, carbon dioxide and high temperature environment.

　　 For resin lens materials, it is necessary to avoid contact with chemicals. Especially for polycarbonate lens materials, avoid contact with acetone, ether and quick-drying glue during processing or use.

　　Resin coated lens maintenance

　　resin lens After the surface is coated, the clarity and blocking harmful ultraviolet rays, which are important for eye protection, are greatly improved. Especially for distance glasses, because they are often worn and often outdoors, the benefits of coated lenses to the eyes are incomparable with ordinary lenses. . However, if you do not pay attention to use and maintenance, the film on the surface of the lens will be corroded and scratched. As the depth of the focusing lens increases, various functions and sharpness will gradually decrease, which will affect the wearing effect. Therefore, special attention should be paid to the maintenance of resin-coated lenses:

　　 1. In addition to scratching, touching, and high temperature, coating resin lenses should also avoid acid fume, etc. Erosion, such as in daily life, it is best not to wear glasses to cook, especially when the ventilation is not good, and there is too much oily smoke; at the same time, it is also not allowed to wear (bring) mirrors into (near) hot water shower environment. Normally, the lens should be convex face up when temporarily placed. , You should put the glasses in the box when you carry it, don’t just put them in your pocket or bag, it will easily scratch the film;

　　 2. It is easy to get dirty and not easy to clean. If you wipe it with a regular cloth, the fiber is rough and hard, which may quickly cause the surface of the lens to produce net-like aspheric lens scars. The easiest and most suitable method is to wash in cold water: After rinsing the glasses with tap water, hold the edge of the frame or pinch the crossbeam with one hand, and use the clean thumb and index finger of the other hand to apply neutral hand sanitizer or detergent. Gently rub and wash both sides of the lens, then rinse with clean water, and then use a cotton towel or paper towel to absorb the water (the intensity of rubbing and washing should be gentle and moderate, because some people's hands have thick skin or the hands and mirrors are stained. Coarse dust particles are not washed away, too much force will wear the lens) so that the lens can be easily washed very clean and safe. Usually when it is inconvenient to wash or the lens is not very dirty, you should only wipe it moderately with a special lens cloth or lens paper. Proper use and maintenance can keep the lens in good condition for a long time and keep your eyes under the best 'protection' at all times.