What are the Types of Lenses?

Views: 126     Author: Site Editor     Publish Time: 2020-08-19      Origin: Site

What are the Types of Lenses?

Lens is a transparent material with the curved surfaces made of glass or resin and other optical materials. After polishing, it is often assembled with the eyeglass frame to form pc reading glasses, which are used to correct the user's vision and obtain a clear vision. There are many ways of lens classification, which can be classified according to lens material, function and surface treatment process.



Classification by Material


1. Glass Lens


The main raw material of glass lenses is optical glass, which has superior optical properties, good transmittance and mechanochemical performance, constant refractive index and stable physical and chemical properties. And the surface of the glass lens has high hardness and is more resistant to wear. However, due to the heavy weight of the glass lens, it affects its wearing comfort to a certain extent. In addition, the glass lens itself is fragile. With the improvement of the production technology and process of resin lenses, in recent years, the use of glass lens is less and less.



2. Resin Lens


Resin is a kind of hydrocarbon secretion from coniferous plants, which is valued for its special chemical structure. Resins can be divided into natural resins and synthetic resins. Resin lenses are lenses that are chemically synthesized using resin as a raw material and processed and polished. Resin lenses have obvious advantages. First, resin lens is light in weight and more comfortable to wear. Secondly, resin lens has strong impact resistance, resin lens is safe and not fragile. At the same time, resin lens has good light transmission. In addition, resin lens is easy to be reprocessed to meet special needs. With the innovation and improvement of the coating process, resin lenses also have good wear resistance, so it becomes the mainstream of lenses on the market.



3. PC Lens


The chemical name of PC lens is polycarbonate, which has toughness and is not easily broken. It can effectively prevent the lens from breaking during intense exercise. At the same time, the PC lens is light in weight and has good anti ultraviolet performance. However, due to the high price, processing difficulties and inadequate dispersion control, PC polarized sunglasses have only a small market share.



Classification by Function


1. Daily General Lenses


It refers to the general single focus optical lens without special functions, which is the most widely used optical lens.



2. Protective Lens


(1) Anti Blue Light Lens


The anti blue light lens is a kind of digital protective lens, which can effectively block the high-energy and harmful blue light, retain the beneficial blue light, and reduce the damage of blue light to eyes. It is suitable for wearing the anti blue light reading glasses when using LED digital display devices such as TV, computer, pad and mobile phone.



(2) UV Resistant Lens


With the help of metal powder, tr90 plastic sunglasses selectively absorb part of the wave band of the sun's light to block the uncomfortable strong light.



(3) Polarized Lens


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



(4) Intelligent Color Changing Lens


It is also called "photosensitive lens". Generally, the color change is realized by adding silver halide substance to the lens itself or by rotating the color changing film on the surface of the lens. The lens darkens under strong light, and the lens becomes transparent under indoor light. The color of the lens is automatically adjusted according to the light intensity.



(5) Sports Lens


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, is not fragile and safer.



3. Progressive Multifocal Lens


Progressive multifocal lens refers to a lens with multiple focal points. The curvature of the front surface of the lens increases continuously from the top to the bottom. The diopter force increases gradually and continuously from the far use area at the top of the lens to the near use area at the bottom of the lens to reach the required near use diopter. A pair of glasses will allow you to see not only objects at a distance, but also objects at a close distance, and also objects at an intermediate distance.



Classification by Surface Machining



Spherical Lens


The spherical lens has spherical radians on both sides. When light of different wavelengths is incident on the lens at different positions after the parallel optical axis, it cannot be focused into a point on the plane, which causes aberration problems that affect the quality of the image. There are distorted images around the lens, limiting the vision of the wearer.



Aspherical Lens


The surface radian of the aspherical lens is different from that of the ordinary spherical lens. In order to pursue the thinness of the lens, the curved surface of the lens needs to be changed. The aspherical design is used for image correction, solving the problem of distortion in the field of view while making the lens lighter, thinner and flatter. Moreover, it still maintains excellent impact resistance, making the wearer safe to use. In the era of continuous progress in science and technology, the application of aspheric design reduces the edge aberration of the lens to the lowest level, so that its wide vision can meet the needs of customers. In the case of high diopter, it can reduce the deformation of the eyes. For consumers with high visual strength, aspheric lenses may be more suitable.


Nowadays, wearing anti blue light blocking glasses is a symbol of wisdom and fashion. Whether it's corrective tool or fashion decoration, it's very important for our eyes to choose suitable lenses, and our life will be more and more brilliant.

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