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Optometry Phoropter High Hardness And Not Easy To Crack
Jun 23, 2017

First, wear-resistant film (dura mater)

Whether it is inorganic materials or organic materials made of glasses, in the daily use, due to dust or gravel (silica) friction will cause lens wear, scratches on the surface of the lens. Compared with the glass, organic materials made of relatively low hardness, more prone to scratches. Through the microscope,Optometry Phoropter we can observe the lens surface scratches are divided into two kinds;

First, due to gravel produced scratches, shallow and small, wearing glasses are not easy to detect; the other is produced by the larger gravel scratches, deep and rough surrounding, in the central area will affect the vision.

(1) technical characteristics

1, the first generation of anti-wear film technology

Anti-wear film began in the early 1970s, when the glass lens is not easy to wear because of its high hardness, and organic lenses are too soft so easy to wear. So the quartz material in the vacuum conditions plated on the surface of organic lenses to form a layer of very hard anti-wear film, but because of its thermal expansion coefficient and the matrix material does not match, it is easy to stripping and film fragmentation,Optometry Phoropter so anti- Wear effect is not ideal.

2, the second generation of anti-wear film technology

After the 1980s, the researchers found that the mechanism of wear is theoretically not only related to hardness, but also has some "hardness / deformation" of the dual properties of the material, that is,Optometry Phoropter some of the material hardness is higher, but the deformation is small, and some Material hardness is low, but the deformation is larger. The second generation of anti-wear film technology is through the soaking process in the organic lens surface coated with a high hardness and not easy to crack the material.

3, the third generation of anti-wear film technology

The third generation of anti-wear film technology is developed after the 20th century, 90 years, mainly to solve the organic lens coated with anti-reflective film after the wear resistance problem. Because of the hardness of the organic lens base and the hardness of the antireflective film, the new theory suggests that there is a need for a layer of wear-resistant film between the two that allows the lens to be cushioned when subjected to gravel friction And not easy to produce scratches. The hardness of the third generation of anti-wear film material between the anti-reflective film and the hardness of the film between the film, the friction coefficient is low and not easy to crack.

4, the fourth generation of anti-wear film technology

The fourth generation of anti-film technology is the use of silicon atoms, such as France Essilor's TITUS (TITUS) plus hard liquid contains both organic matrix, but also contains silicon-containing inorganic ultrafine particles, so that wear-resistant film With toughness while improving the hardness. Modern anti-wear film technology is the most important way to use immersion, that is, after a multi-channel cleaning lens,Optometry Phoropter immersed in the hard liquid, after a certain period of time to a certain speed. This speed is related to the viscosity of the hardened solution and is critical to the thickness of the wear resistant film. After the addition of 100 ° C in the oven about 4-5 hours, the coating thickness of about 3-5 microns.

(2) test method

The most fundamental way to judge and test the abrasion resistance of abrasion resistant membranes is to use them so that the wearer wears for a while and then observes and wears with the lens. Of course, this is usually in this new technology before the formal promotion of the method used, we often used more rapid and intuitive test method is:

1, frosted test

The lens placed in the gravel containing promotional materials (the provisions of the gravel of the particle size and hardness), under certain control for back and forth friction. After the end of the lens with a haze meter to measure the amount of light diffuse before and after the friction, and compared with the standard lens.

2, steel velvet test

With a specified steel velvet, at a certain pressure and speed, the number of times the friction on the surface of the lens, and then use a haze meter to test the lens before and after the light diffuse reflection, and compared with the standard lens. Of course, we can also manually manipulate the same number of times the same pressure on the two lenses, and then use the naked eye to observe and compare.

The results of the two test methods and wearing glasses who wear long-term clinical results are relatively close.

(3) the relationship between the anti-reflective film and the anti-wear film

The anti-reflective film on the surface of the lens is a very thin inorganic metal oxide material (thickness less than 1 micron), hard and brittle. When coated on the glass lens,Optometry Phoropter the base is relatively hard, gravel over it, the film is relatively easy to produce scratches; but the anti-reflective film is coated on the organic lens, the film is soft, gravel in the film Layers across the film is prone to scratches. Therefore, organic lenses must be plated with anti-wear film before plating, and the hardness of the two layers must match.

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