According to different materials, lenses can be divided into glass lenses, resin lenses, PC lenses, and crystal lenses. The following is an introduction to the various materials of the lens:
(1) Glass lens
The main raw material of glass lenses is optical glass, which has superior optical properties, good light transmittance and mechanical and chemical properties, constant refractive index, and stable physical and chemical properties. Secondly, glass lenses have a higher refractive index and are often used for lens purposes. The highest refractive index is 1.9. Finally, the surface of the glass lens is harder and more resistant to abrasion.
However, the weight of the glass lens is relatively large due to the material, which affects its wearing comfort to a certain extent. In addition, the glass lens itself is fragile, especially with the improvement of the production technology and process of the resin lens. In recent years, the glass lens has been used fewer and fewer.
(2) Resin lens
Resin is a kind of hydrocarbon (hydrocarbon) secretions from plants, especially coniferous plants, and is valued for other special chemical structures. Resins can be divided into natural resins and synthetic resins, and resin lenses are lenses that are chemically synthesized using resin as raw materials and processed and polished. The resin lens has obvious advantages, its weight is lighter, and it is more comfortable to wear; secondly, the resin lens has strong impact resistance, is not fragile and safer; at the same time, the resin lens also has good light transmission; in addition, the resin lens is easy to reprocess to meet special needs Finally, coupled with the innovation and improvement of the coating process, the resin lens also has good abrasion resistance, so it has become the mainstream of the lens on the market.
(3) PC lens
PC lens, also known as space film, chemical name is polycarbonate, it is tough, not easy to break, can effectively prevent lens fragmentation during intense exercise, at the same time, PC lens is light in weight, specific gravity is only 2 grams per cubic centimeter, and has good properties. However, due to high price, troublesome processing and insufficient dispersion control, PC lenses are only sold in a small amount on the market.
(4) Crystal lens
Crystal is a transparent quartz crystal, the main component is silicon dioxide. Its refractive index and density are higher than glass lenses. The advantages of crystal lenses: high hardness, high temperature resistance, friction resistance, and moisture resistance. The disadvantages are: high hardness, difficult processing, heavy weight, and expensive. Most of these natural crystals have impure texture and uneven color, which reduces the light transmittance. Its optical performance is inferior to glass, and it is basically not used at present.