How to distinguish the quality of plastic lenses?

- How to identify inferior Korean resin lenses When it comes to resin lenses, most people who wear glasses know; Plastic lenses are gradually accepted by many patients with refractive error due to their light weight and impact resistance, and have become the mainstream of spectacle lenses. In this case, some inferior plastic lenses have also quietly entered the market, and consumers have little knowledge about spectacle lenses, and generally cannot accurately distinguish between fake and inferior; The following is an introduction to how to distinguish the advantages and disadvantages of inferior Korean plastic lenses. First of all, look at the hardness of the lens, the resin lens itself due to the low hardness of the factory must go through strict surface hardening treatment to meet the wear-resistant requirements of wearing, otherwise generally after two or three months of wearing, the surface of the lens 'rubbing' is more serious, and even can not be worn, and the hardness of the resin lens wear resistance is much better, only a small number of scratches after a few months of wearing, which does not affect the wearing. For example, the hardness of Japanese TAG Heuer resin lenses can reach 7h, and one of the ways to compare with inferior Korean lenses is to use a drawing pencil with a hardness of 6h to wipe the surface of the lens with the usual writing force, if there are scratches on the surface, it means that the hardness of the lens is not enough.

Secondly, looking at the color, high-quality plastic lenses do not have any background color (if the coated lens film layer is colored), while the background color of low-quality Korean lenses is slightly blue, and it is easy to turn yellow after wearing it for a period of time. In addition, the center thickness of inferior Korean plastic lenses is thinner, and the edges look thinner than lenses with the same refractive index, so it is wrong to sacrifice the center thickness to make the lens thinner, because plastic lenses are called "safety lenses" unlike glass lenses, and there is a minimum value of center thickness, and wearing such lenses is at the expense of the safety of your eyes. At present, the high-quality plastic lenses in the domestic market include Japan's 'Heuer', the United States' Suna', France's 'Essilor' and other well-known brands, among which Japan's Tag Heuer's resin lenses are the best, with a rich variety of cuts.

If you can't accurately identify the inferior Korean resin lenses, then you'd better go to a large optical store with a good reputation to match the plastic lenses, because there are few regular products in the domestic market that are allowed to be imported by the country.

Optical properties of resin lenses: 1The surface gloss and smoothness of plastic lenses are in no way inferior to those of ordinary glass lenses.

2.The refractive index of plastic lenses is lower than that of ordinary glass lenses, so plastic lenses of the same power are thicker. 3.

The dispersion of plastic lenses is very similar to that of glass lenses. 4.The see-through rate of plastic lenses is 92%, which is more than 2% higher than that of ordinary glass lenses.

5.The surface reflection of plastic lenses is lower than that of ordinary glass lenses, and they are less dazzling, which is due to their higher light transmittance and lower refractive index. 6.

The bifocal lenses of plastic lenses are composed of a single piece, and are not made of fusion like ordinary glass bifocal lenses, so there is no chromatic aberration in plastic bifocal lenses. 7.The optical properties of plastic lenses are extremely stable and do not change at high or low temperatures.

Mechanical properties of plastic lenses: 1Plastic lenses can be cast into a wide range of shapes with high transparency and optical requirements.

2.Plastic lenses are easier to frame than glass lenses. 3.

Plastic lenses are easy to dye and can be dyed into a variety of colored lenses with different light transmittance as needed. Physical properties of plastic lenses: 1

Plastic lenses are lightweight, and their weight is only half that of regular glass lenses. 2.Plastic lenses are particularly impact-resistant.

3.When the resin lens is shattered by impact, there are fewer fragments, and the fragmentation area is large and blunt; Minimise injuries to the eyes and face. 4.

Even after long-term use, the surface of the plastic lens is not prone to breakage. 5.Plastic lenses have strong impact resistance to high-temperature, small-sized objects, and when such objects hit the plastic lenses, they will immediately bounce open; It is not like ordinary glass lenses, which can easily cause dents and spots.

Therefore, when welding or using grinding wheels, plastic lenses can be used to protect the eyes from flying fire dust. 6.Because plastic lenses have low thermal conductivity, they have better anti-fogging properties than conventional lenses.

Chemical properties of plastic lenses: 1Plastic lenses are resistant to chemicals and chemical solvents in a wide range.

With the current household chemicals and chemical solvents, almost no harm will be caused to plastic lenses. 2.Plastic lenses have low thermal conductivity, and when heated, they have extremely high heat resistance, and are not prone to bending and torsion deformation at a certain high temperature.

Due to the above characteristics, plastic lenses have gradually replaced glass lenses in recent years.

Usually, you look at the light to see if the lenses have a slight green light, the more obvious this green light is, the better the lenses! With so many theories above, how do you use them in an optical store?

1. Look at whether the light transmittance is good or not, and see if there are bubble impurities in it.

2. Look at the hardness of the lens. Plastic lenses.

Due to the low hardness of the factory, it must go through strict surface hardening treatment before leaving the factory to meet the wear-resistant requirements of wearing, otherwise the scratching on the surface of the lens is generally more serious after two or three months of wearing, and even can not be worn, and the wear resistance of the resin lens with qualified hardness is much better, and there are only a few scratches after wearing for a few months, which does not affect the wearing.

3. Looking at the color, high-quality plastic lenses have no background color (if the coated lens film has color), while the background color of inferior lenses is slightly blue, and it is easy to turn yellow after wearing for a period of time.

This generally requires professional technology and equipment.

With the naked eye and a simple test, see if the light transmittance is good, see if there are bubble impurities in it, and use pencils of different hardness to scratch the lens.

1. The raw materials are different

The main raw material of glass lenses is optical glass; Resin slip lens is an organic material, the inside is a polymer chain structure, connected and three-dimensional network structure, the intermolecular structure is relatively relaxed, and there is space between the molecular chains to produce relative displacement.

2. Different hardness:

Glass lenses are more scratch-resistant than other lenses made of rough and wide materials, and are not easy to scratch and shine; The surface hardness of plastic lenses is lower than that of glass, and it is easy to be scratched by hard objects, so it needs to be hardened, and its hardening material is silica, but the hardness can never reach the hardness of glass, so the wearer needs to pay attention to the maintenance of the lens;

3. The refractive index is different

Glass lenses have a higher refractive index than plastic lenses, so they are thinner than plastic lenses at the same power. The light transmittance and mechanical and chemical properties of glass lenses are relatively good, with a constant refractive index and stable physical and chemical properties.

The refractive index of plastic lenses is moderate, ordinary CR-39 propylene diethylene glycol carbonate, refractive index, the highest refractive index of plastic lenses sold in the Shenyang glasses market is aspherical ultra-thin and hard film resin lenses, the refractive index can be reached, and there are now resin lenses with refractive index.

Optical glass has better thermal conductivity than resin and is cooler to the touch. Optical glass is a bit heavier than resin. If you can see the edging of the eye, the edging is generally the frosted glass and the mirror resin.

The lens, also known as the mirror core, is a framed painting center, which is suitable for being sandwiched in the picture frame, so it is called the mirror core. Its form can be horizontal or vertical, and the installation is simple and convenient.

The main raw material of optical glass lens is optical glass. It has a higher refractive index than plastic lenses, so glass lenses are thinner than plastic lenses to the same extent. Optical glass lenses have good light transmittance and mechanical and chemical properties, with a constant refractive index and stable physical and chemical properties.

Lenses without color are called optical white mounts (white lenses), and pink lenses in color lenses are called Crocker lenses (red lenses). Crocker lenses can absorb ultraviolet rays and slightly absorb bright light.

Resin is a hydrocarbon secreted by a variety of plants, especially pine and cypress. Due to its special chemical structure, it can be used as an emulsion paint and a poor adhesive. It is a mixture of various polymer compounds and hence has a different melting point.

Resins can be divided into natural resins and synthetic resins. There are many kinds of resins, which are widely used in people's light industry and heavy industry, and can often be seen in daily life, such as plastics, resin glasses, coatings, etc. Plastic lenses are lenses that are chemically processed and synthesized from resin.