What is the hydrophobic oil layer on your mobile phone screen?
Because of Huawei P10 screen is concerned by more and more people, caused a very heated discussion in the internet at the same time. Meanwhile some of people focus on this question: What is the hydrophobic oil layer? What is this hydrophobic oil layer used for? Is there any difference between hydrophobic and sparse oil?
In fact, hydrophobic oil layer is very common in life, but we usually did not notice it when we come into contact with it.
Interpretation of hydrophobic and oleophobic layers
Hydrophobic oil layer, that in fact is that can alienate the protective layer of water and grease, and we have heard the anti-fouling coating, is same thing, that is named AF (Anti Finger Print) fingerprint coating, the English called “Oleophpbic coating”, usually we feel our new mobile phone screen smooth is from the hydrophobic oil layer.
AF material is a fluorine coating, with a very low surface tension, commonly known as perfluoropolyether, the main role is attached to the screen surface, increase the screen of hydrophobic, oil, anti-fouling and other properties, it widely used in mobile phones, Flat, monitor, SLR on the protection of glass, we basically have access to it with a screen of electronic products. The hydrophobic and oleophobic expressional effect just like the drop on the lotus leaf.
Drops of water on the lotus leaf
AF material is mainly divided into two kinds of liquid and the target pills (similar to small pills), respectively, for spraying and vacuum deposition two kinds of coating. Glass coating, and then after high temperature curing, AF coating is retained to the screen surface, in addition to anti-fouling, AF coating also has a wear-resistant, high transmittance characteristics, and the cost is particularly low, spray single-chip cost is not higher than 6 cents, vacuum deposition of single-chip cost is less than 3 RMB, slightly higher concentration of AF coating can be kept good condition for 1-2 years.
hydrophobic oil layer – Vacuum Evaporation Equipment
Of course, hydrophobic oil layer is not only used for glass, but also can have such a protective layer on stainless steel. At present, the relevant coating liquid sold in the market, sprayed on a variety of metal materials such as stainless steel plate surface, can form a layer of nano / micron-class ultra-thin anti-oil anti-fingerprint self-cleaning coating, can make the water with high Surface tension (manifested as water repellency), the formation of a higher water contact angle of the water droplets, so that oil contraction into difficult to attach to the metal surface of the small oil droplets, a small amount of residual oil can be easily wiped with a towel or paper towel clean.
The hydrophobic layer waterproof testing
What is the use of hydrophobic oleophobic in daily life?
At now, let’s give an example simple explanation: As the current 2.5D screen is more popular, many people will choose the ordinary mobile phone protection film, but cheap mobile phone protection such as some tempered glass there is no hydrophobic layer on the membrane. This protective film in the sliding touch is obviously more jerky and rough. When we play the phone for a long time, the protective film will leave a lot of fingerprints, and not easy to wipe clean, and will further increase the sliding resistance.
Similarly, the phone screen glass there is no hydrophobic sparse layer of a reason with above. There is no hydrophobic oil layer will have a more obvious sense of sliding resistance, and easy to stay fingerprints stains and easy to wipe. There are hydrophobic oleophobic panel glass in the touch sliding resistance will be reduced a lot, although the fingerprint still stay, but easier to wipe.
How to check whether there is a hydrophobic layer on the screen?
The more professional identification method is through the water droplet contact angle tester to test the glass surface characteristics, from the water droplets angle to indirectly analyze the degree of hydrophobic glass surface, to determine the product surface anti-fouling.
The angle of water droplets is defined as the angle between the interface between the gas-liquid interface and the solid-liquid interface at the interface of solid, liquid and gas. The water droplet angle is the scale that shows the surface humidity of the solid surface. The low exposure to water droplets indicates a high humidity (hydrophilic) surface that is easy to paste. The high water droplet contact angle indicates that the surface shows hydrophobicity, the surface organic pollution is heavy or the surface adhesion is poor.
The contact Angle of the water droplet contact angle
Of course, we ordinary do not need such professional judgment. We just put the water on the phone screen, if the contact water droplets angle showed the obtuse angle, then the glass surface added hydrophobic oleophobic layer, if the contact water angle is acute and angle is small, then the glass surface is not covered with hydrophobic oleophobic layer. At the same time, the glass that there are hydrophobic oleophobic on the surface is waterproof. the water can rely on gravity on the screen sliding.
Without hydrophobic oil layer (Left). With hydrophobic oil layer (Right)
You can also use a small sprayer, sprayed toward the screen. If the glass surface to form many small water droplets, then the glass surface covered with hydrophobic oleophobic layer; if the water is looked like a piece on the glass, the glass surface is not covered with hydrophobic oleophobic layer.
There is no hydrophobic oil layer ( Down), There is hydrophobic oil layer (Up)
Although the hydrophobic oil layer can be kept to a certain extent, kept the screen smooth and clean, but hydrophobic oleophobic layer will be easy to produce wear and tear with the use of time, the hydrophobic oleophobic effect will gradually weaken, which is the reason old mobile phone screen glass is more easier to dirty. Of course, people almost don’t let the phone screen streaking without protector, most of users will film the phone after buy mobile phone, so the phone glass panel surface is not hydrophobic oleaginous layer does not need too much care.