Optical lens cleaning and coating test method
1. Treatment of optical lens contamination: If the surface of the optical lens lens is stained with dirt, fingerprints, rust, oil stains, etc., it will affect the image quality and should be removed in time. But don't deal with it rashly, otherwise it will easily damage the lens.
After dusting the surface of the lens, you can blow the dust off with a clean balloon a few times. Do not blow with your mouth to avoid saliva splashing on the mirror surface; not to use your fingers To wipe. If the surface of the lens is stained with fingerprints, water stains, oil stains, acid or alkali, etc., use absorbent cotton dipped in a little anhydrous alcohol and ether mixture 1:1 to gently wipe. The method of wiping should be gently wipe from the center to the edge (only one direction can be wiped gently). After wiping some amount, replace with new cotton and wipe again. For the coated surface, try not to wipe it to avoid the film surface from falling off.
2. Lens moldy treatment: Lens moldy generally includes optical lens biological mold and chemical mold.
(1) Biological mold: It is adsorbed on the surface of the lens and takes the shape of pompons, spider webs, and roots. Removal method: same as removing fingerprints and water stains. When the edge of the lens becomes moldy, the lens must be taken out and wiped carefully. The position of the lens should be recorded before the lens is taken off, and the position must be restored when the lens is installed to avoid lens misalignment or reverse installation. It is better to return to the factory to scrub and reinstall.
(2) Chemical mold: The lens is actually corroded. Because the film structure of the lens is sponge-like and full of voids, it will cause 'hydrolysis' after being corroded by water in the air, and gradually corrode the film first, causing the film to peel off, and the surface of the lens appears spot-like. In severe cases, the lens can be corroded. In this case, it should be sent to a professional factory for treatment.
The most fundamental way to judge and test the wear-resistant optical lens performance of the anti-wear film is clinical use. Let the wearer wear the lens for a period of time, and then observe and compare the lens with a microscope. Wear and tear. 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
Place the 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 light before and after the lens is rubbed, and compare it with the standard lens.
(2) Steel wool test
Using a specified steel wool, under a certain pressure and speed, 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. Of course, we can also manually operate the focusing lens, rub the two lenses the same number of times with the same pressure, and then observe and compare them with the naked eye.
The results of the above two test methods are relatively close to the clinical results of long-term wearers.
(3) The relationship between anti-reflection coating and anti-wear coating
The anti-reflection coating on the surface of the lens is a kind of 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. Scratched on the layer, the film is easily scratched.
Therefore, the organic lens must be coated with an anti-wear coating before the anti-reflection coating is coated, and the hardness of the two coatings must match.
Aspherical lenses and organic lenses are more difficult to coat than glass lenses. Glass materials can withstand high temperatures above 300°C, while organic lenses will turn yellow when it exceeds 100°C and then quickly decompose.
The anti-reflection coating material that can be used for glass lenses usually uses magnesium fluoride (MgF2), but the coating process of magnesium fluoride must be in an environment higher than 200°C Otherwise, it cannot be attached to the surface of the lens, so organic lenses do not use it.
Since the 1990s, with the development of vacuum coating technology, the use of ion beam bombardment technology has made the combination of the film and the lens and the combination of the film improved . Moreover, the refined high-purity metal oxide materials such as titanium oxide and zirconium oxide can be plated on the surface of the resin lens through an evaporation process to achieve a good anti-reflection effect.