What is a watch mirror?
LOOKING GLASS: The transparent lens on the watch surface, also called watch glass, used to protect the watch surface (dial). Table mirrors can be divided into three categories: plastic mirrors, quartz glass mirrors, and sapphire mirrors according to their materials. Rubber lenses are relatively resistant to falling, and sapphire crystals are the most wear-resistant.
Table mirror type
1. Sapphire crystal glass table mirror
Sapphire is a kind of natural diamond, which has high anti-wear and anti-corrosion effects after being synthesized with alumina. The hardness is 2200-2300 domains (seven times the hardness of steel), Mohs hardness is 9, its hardness is second only to diamond, high hardness, good optical permeability, low friction, high temperature resistance, wear resistance, it can solve scratches , Aging, corrosion and other problems, but fragile. Commonly used as watch mirror and see-through bottom cover. (Generally used for high-end watches.)
Can sapphire crystal be polished on the ground or ordinary glass? No, because the ground or ordinary glass may contain diamonds or diamond powder and impurities, if it touches it, the sapphire crystal will be scratched; another situation is that a substance softer than sapphire crystal sticks to the sapphire crystal, causing the sapphire The crystal is scratched, which is a false scratch, which can be restored by the master.
2. Synthetic glass mirror
Synthetic glass, commonly known as acrylic, or plexiglass, is a kind of material for watch mirrors, with softer texture and higher plasticity. Most watches in the past used this material, but many watches are still in use today.
The disadvantage of this material is that it is easily scratched and its transparency is slightly poor. Although it is easy to scratch, when it is scratched, people can ask the watchmaker to polish it directly on the glass to restore the original smooth mirror surface, so there is no need to replace the lens. If the scratches are too deep, you can also choose to replace the mirror directly. The acrylic mirror is very cheap. The advantage is that it has very good elasticity and is not easy to break, so it is also called safety glass. The strength of plexiglass is relatively high, and its tensile and impact resistance are 7-18 times higher than ordinary glass. There is a kind of plexiglass that has been specially heated and stretched, and the plexiglass is nailed into the plexiglass. Even if the nail penetrates, the plexiglass will not crack. Because of this feature, it is widely used in military machinery, such as the canopy on aircraft, such as the windshield on armored vehicles, and many of the earliest pocket watches.
3. Mineral crystal glass table mirror
Mineral crystal glass is a kind of watch mirror material. It is usually polished to increase the hardness, but the hardness is still inferior to that of the sapphire crystal. Mineral crystal glass is called artificial crystal. Because natural crystal is scarce and difficult to mine, it cannot meet people’s needs, and artificial crystal glass was born. Because of its high permeability, it can be made into various handicrafts and is favored by the world. Mineral crystal glass is made of silicon (Silica) and lead oxide (the subsequent lead-free crystal uses other materials, such as potassium oxide, barium oxide, etc.). It makes the crystal particularly shiny. The clarity comes from polishing technology. quality.
4. What is the anti-glare mirror often heard?
To put it simply, anti-glare mirror is to electroplate a multi-layer film on the lens to attach it to the lens to prevent light refraction. It is similar to car heat insulation paper, also called multi-layer film or colored clothing. On a table with a large mirror curvature. And it is divided into double-layer anti-glare glass and single-layer anti-glare glass. The difference is that the former is electroplated on both sides of the lens, while the latter is only coated on the inside of the glass. The effect of the two is not much different.
The difference between mineral crystal glass, synthetic glass and sapphire crystal glass
The appearance of mineral crystal glass, synthetic glass and sapphire crystal glass are very similar, but they are three completely different substances. The main differences are as follows:
1. Different materials: mineral crystal glass is a crystal of silica, synthetic glass is only a molten mixture containing silica, and sapphire crystal glass is aluminum oxide with impurities such as iron oxide and titanium oxide removed .
2. Different prices: Sapphire crystal glass has the highest price, followed by mineral crystal glass, and the cheapest is synthetic glass.
3. Different hardness: sapphire crystal glass has the highest hardness (Mohs level 9), while mineral crystal glass is crystalline and also has a higher hardness (Mohs level 7). The hardness of synthetic glass is low, (Mohs 5.5).
4. Different processing technology: Synthetic glass can be formed by hot casting, saving materials and labor, and low cost. Mineral crystal glass and synthetic crystal glass are crystals, which cannot be reversed after being heated and melted. Therefore, hot casting molding method cannot be used, but cold working methods such as cutting and grinding can only be used. The sapphire crystal glass is made of crystal powder heated above 2000°C. Then, the formed sapphire block is cut into exquisite slices with extremely high precision, and then trimmed and polished to be used as watch glass.
How to identify these three kinds of glass watch mirrors?
First, you can tap your finger on the mirror and listen carefully. Acrylic mirrors make a sound like plastic, while glass makes a thicker sound. Secondly, from the perspective of weight, the acrylic mirror is the lightest and the sapphire mirror is the heaviest. Because sapphire has a good thermal conductivity, it will feel cold when you touch it with your hands. Since the sapphire mirror surface is much smoother than the mirror surfaces of the other two materials, if you drop a drop of water on the sapphire mirror surface, the water droplets will not spread easily, while the other materials will disperse into one piece.
Post time: Oct-11-2020