(1) Sapphire is a kind of natural diamond, which has high anti-wear and anti-corrosion effects after being synthesized with alumina. Hardness is 2200-2300 domain (seven times the hardness of steel), Mohs hardness is 9, its hardness is second only to diamond, high hardness, good light transmittance, low friction, high temperature resistance, anti-wear, commonly used as watch crystal And a see-through bottom cover.
(2) mineral crystal glass
Hardness is 500-800 domain, Mohs hardness is 5, usually after polishing to strengthen the hardness, but the hardness is still slightly inferior to the sapphire crystal mirror.
(3) Synthetic glass
Plastic glass refers to acrylic. Most of the past Watches Factory use this material, and there are still many models in use. The disadvantage is that it is easy to scratch and has a slightly poor transparency, but it is also called safety glass because it has elasticity and is not easily broken. Although plastic glass is easy to scratch, when it is scratched, it can be polished directly on the glass to make it smooth, without having to change the lens, unless the mark is too deep and the price is cheap.
(4) Anti-glare glass
What is the anti-glare glass often heard?
Simply put, the anti-glare glass is a multi-layer film on the lens that is attached to the lens to prevent light from refracting. Similar to automotive insulation paper, also known as multi-layer film or color clothing, is often used in professional aviation, diving watches or The mirror has a large curvature on the surface. It is divided into double-layer anti-glare glass and single-layer anti-glare glass. The difference is that the former is plated on both inner and outer sides of the lens, while the latter is only coated on the inner side of the glass. The effect of the two is not much different.
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