In this article, we mainly talk about how we test the quality of glasses lenses. For us, the quality of the lens depends on its appearance and function.
We all know that the lens is one of the most important parts of a pair of glasses, the quality of the lens is directly related to the quality of the glasses. We spend a lot of money, and we definitely hope to buy a pair of good glasses. It is definitely easy to choose a pair of glasses that you like in terms of appearance, but the function of the lenses is also very important. Let’s take a look at how the factory inspects the quality of the lenses. Of course, if you are an ordinary consumer, I hope it will be of some help to you.
1. Appearance inspection. For color, variegated color, pitting, scratches and other surface problems. Put a piece of non-polluting white paper under it, and carefully check whether there are any of the above problems under the QC light (stronger and more uniform light than ordinary daylight).
2. Specification check. Because the lens is generally round, we need to use an oil dipstick caliper to measure the diameter and thickness of the lens.
3. Anti-friction test. Use a certain rough paper or cloth or other materials to rub the surface of the lens back and forth for a certain number of times with a certain force, and then see the effect. High-quality lenses have better anti-friction effect.
4. Camber inspection: Check the camber of the lens with a camber meter. The inspection point is the curvature value of the center of the lens and at least 4 points around it. In the subsequent batch inspection, place it flat on the glass plate to check whether it is evenly in contact with the glass plate.
5. Impact resistance test. Also called the drop ball test, use a drop ball tester to test the impact resistance of the lens.
6. Lens function test. First of all, it depends on the specific functions of the lens, and then conducts the corresponding test. The common ones are oil-proof, waterproof, strengthened, etc., UV400, polarized, etc.
• A. Oil-proof function test: Use an oil-based pen to draw on the surface of the lens. If it can gather together quickly, wipe it off with the lens lightly, indicating that it has oil-proof function. Observe the degree of oily water gathering together, and wipe it off. Clean degree, examine its anti-oil effect.
• B. Waterproof function test: put the lens into clean water and take it out, shake it lightly, the water on the surface will fall off, indicating that the lens has waterproof function. Check the waterproof effect according to the degree of drop.
• C. Strengthening function test: Under the QC light, observe whether there is a transparent glue layer on the surface and the periphery of the lens, and gently squeeze it with a blade. It has relatively good strength and toughness.
• D. Polarization function test: test with a polarizer. Or open the computer WORD file, and then hold the lens facing it and rotate it clockwise, the color of the lens will change from light to dark and then completely black, and continue to rotate from black to light gradually. It is a polarizer. Pay attention to observe the uniformity of the color, etc., and whether it is dark enough to judge the quality of the polarizing function when it is opaque.
• E. UV400 means 100% UV protection. Sunglasses on the market may not all have the effect of isolating ultraviolet rays. If you want to know whether the lenses can isolate ultraviolet rays: find an ultraviolet money detector lamp and a bank note. If you directly illuminate it, you can see the ultraviolet anti-counterfeiting of the banknote. If through the lens with UV400 function, the anti-counterfeiting cannot be seen.
The above are some inspection and testing methods of lenses. Of course, there is no absolute standard for it. Every customer and every brand has different requirements for lenses. Some pay more attention to appearance and some pay more attention to function, so the focus of inspection will also be different.
article source: https://www.hisightoptical.com/news/how-we-check-the-quality-of-the-lens/
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