What are the types of lenses?

Lens, a transparent material with one or more curved surfaces， it is made of optical materials such as glass or resin. After grinding, it is often assembled with the eyeglass frame to form glasses, which is used to correct the vision of users and obtain clear vision. Today, we will introduce the classification of lenses.

Classification by material

Glass lenses

The main raw material of glass lens is optical glass, which has superior optical properties, good transmittance, good mechanical and chemical properties, constant refractive index and stable physical and chemical properties. Secondly, glass lenses have a high refractive index, and the highest refractive index which is commonly used for lens use is 1.9. Finally, the surface hardness of glass lenses is higher, and the wear resistance is better. However, due to the heavy weight of glass , to a certain extent, the wearing feeling of glass lenses is affected. In addition, due to the fragile characteristics of glass lenses, especially with the improvement of production technology and technology of resin lenses, glass lenses have been used less and less in recent years.

Resin lens

Resin is a kind of hydrocarbon (hydrocarbon) secretion from plants, especially from conifers, which is paid attention to because of its special chemical structure. Resin can be divided into natural resin and synthetic resin, and resin lens is the lens formed by chemical synthesis and grinding with resin as raw material. Resin lenses have obvious advantages, they have light weight and they are more comfortable to wear. Secondly, the resin lens has strong impact resistance, and is not fragile. At the same time, the resin lens also has good light transmission. In addition, the resin lens can be easily reprocessed to meet special needs. Finally, with the innovation and improvement of coating process, resin lens also has good wear resistance, so it has become the mainstream lens on the market.

PC lens

PC lens, also known as space film. Its chemical name is polycarbonate. It is tough and not easy to break. It can effectively prevent the lens from breaking during fierce sports. At the same time, the PC lens is light in weight, with a specific gravity of only 2g per cubic centimeter. At the same time, it has good anti ultraviolet performance. However, due to the high price, troublesome processing and poor dispersion control, PC lenses are only sold in a small amount on the market

Classification by function

Daily general lens

Daily general lens is a kind of optical lens with single focus and no special function. It is the most widely used optical lens.

Protective lens

1. Anti blue lens

Anti-blue light lens is a kind of digital protective lens which can effectively block the high-energy harmful blue light, retain the beneficial blue light, and reduce the damage of blue light to eyes. Anti-blue radiation glasses and anti-fatigue glasses for computers are suitable for LED digital display devices such as TV, computers, pads and mobile phones.

2. Sunglasses

With the help of metal powder, sunglasses selectively absorb part of the wave band that makes up the sun's rays and blocks the uncomfortable strong light. Clear frame blue lens sunglasses and clear sunglasses with blue lenses are very suitable for us to wear when going out.

3. Polarizing lens

When the sun shines on the water, road, snow and other places, it will reflect disorderly light. In order to filter the dazzling light, a special vertical coating is added to the lens, which is called a polarizing lens. It can effectively suppress the strong light, and it is not easy to glare even if you look directly at the sun. Polarized blue lens sunglasses and polarized reader sunglasses are most suitable for outdoor sports such as driving, skiing or fishing.

4. Intelligent color changing lens

Intelligent color changing lens is also called "photosensitive lens". Thinoptics glasses and design optics reading glasses darken in strong light and transparent in indoor light, and automatically adjust the lens color according to the intensity of light / ultraviolet light.

5. Sports lens

The safety protection lens pays attention to safety and protection performance. This kind of lens generally refers to the KR super tough lens in PC lens or resin lens, which has high strength and toughness, strong impact resistance and is not fragile.

Progressive lenses

Progressive multifocal lenses have multiple focal points. Progressive multifocal glasses can see not only distant objects, but also near and medium distance objects.