Whether it is an optical lens made of inorganic or organic materials, in daily use, friction with dust or grit (silicon oxide) will cause the lens to wear and scratches on the surface of the lens. Compared with glass flakes, organic materials have lower hardness and are more prone to scratches. Through the microscope, we can observe that the scratches on the lens surface are mainly divided into two types. One is the scratches caused by grit, which is shallow and small, and it is not easy for the wearer to detect; the other is the scratches caused by larger grit , Deep and rough periphery, in the central area will affect vision
test method The most basic method for judging and testing the wear resistance of the anti-wear film is clinical use. The wearer wears the lens for a period of time and then observes and compares the wear of the lens with a microscope. Of course, this is usually the method used before the formal promotion of this new technology. At present, the quicker and more intuitive test methods we commonly use are:
1) Scrub test< /p>
Place the optical lens in a publicity material containing gravel (the grain size and hardness of the gravel are specified), and rub back and forth under certain control. After the end, use a haze meter to test the amount of diffuse reflection of the lens before and after friction, and compare it with the standard lens.
2) Steel wool test
Using a prescribed steel wool, design a certain pressure and speed in a lens Next, rub the number of times on the surface of the lens, and then use a haze meter to test the amount of diffuse reflection of light before and after the lens is rubbed, and compare it with the standard lens.
3) The relationship between anti-reflection coating and anti-wear coating
The anti-reflection coating on the surface of the lens is a very Thin inorganic metal oxide materials (less than 1 micron in thickness), hard and brittle. When it is plated on a glass lens, since the base is relatively hard and the grit is scratched on it, the film layer is relatively difficult to scratch; but when the anti-reflection film is plated on the organic lens, because the base is soft, the grit is on the film. Scratch on the layer, the film is easily scratched.
Laser lenses often keep the optical glass sheet clean, which will increase the life of the optical glass sheet. Because pollution will cause many problems with the lens, the uneven distribution of laser power during reflection makes the lens base temperature high and the marginal temperature low. This change is called the lens effect in the optics.
Failure to comply with the requirements and precautions for lens finishing, and random handling will result in new pollution and even scratches on the optical glass sheet, resulting in unnecessary losses. Usually, you should be careful not to let the mirror directly touch the hard objects. When scrubbing, it is best to clean it with water (or a small amount of detergent), and then use a special test cloth or excellent tissue paper to absorb the water droplets on the spectacle lens. If the lens has no scratches on the high-power laser lens group, it cannot be used all the time.
The processing of lenses is made by high temperature or ultraviolet curing of liquefied monomers. As the service cycle becomes longer, the environment and temperature changes, the film layer on the surface of the lens and the material of the lens itself Changes will occur, resulting in light scattering, decreased comfort, and dry eyes and swelling of the eyes after a long time of use. At this time, it is necessary to replace the optical glass sheet.
The development of optical glass and the development of optical instruments are inseparable. New reforms in optical systems often put forward new requirements for optical glass, thus promoting the development of optical glass. Similarly, the success of trial production of new varieties of glass often also promotes the development of optical instruments.
The first optical material used to make optical parts was natural crystal. It is said that crystal was used as lens in ancient Asilia, while natural tourmaline was used in ancient China ( Tea mirror) and citrine. Archaeologists have proved that glass can be made in Egypt and our Warring States period before 3000 AD. But the use of glass as glasses and mirrors began in Venice in the thirteenth century. Since then, due to the development needs of astronomers and navigation, Galileo, Newton, Descartes, etc. also made telescopes and microscopes out of glass. Since the 16th century, glass has become the main material for manufacturing optical parts.