How does Screen Protector Work?

how the protective coating works

by Alex Gustman

Updated: July 26, 2021

To protect the smartphone screen, users prefer to use tempered glass or PET film. From this article, you will learn how each screen protector works and how effective it is.

How does tempered glass work?

Tempered glass is obtained by thermal or chemical hardening. In the first case, the glass is heated to a critical temperature and then cooled on both sides. In the second case, the tempered glass is placed in a solution of potassium salts, where, under the influence of temperature, sodium ions are exchanged with potassium ions. After quenching, the initial strength of the glass increases by 5-7 times, the resistance to bending is up to 10 times, and the resistance to stretching is up to 6 times.

tempered glass for smartphone

Due to the hardening, the tempered glass absorbs more mechanical energy as a result of impact or falling to the floor. Therefore, the main glass of the screen module has less load. Also, due to the thickness of 0.26, 0.33 or 0.5 mm, high wear resistance is achieved, which eliminates damage in contact with plastic or metal objects. And the presence of stresses on the surface of tempered glass when damaged leads to the formation of fragments with blunt edges, which reduces the likelihood of damage to the owner.

broken tempered glass for smartphone

How does protective film work?

The protective film is made of a polymer material with a thickness of several hundred microns. Therefore, after installation, it is not easy to distinguish the presence of a film. And due to the thickness of the film, it does not interfere with the operation of the ultrasonic fingerprint scanner.

At the same time, the film is not designed to absorb mechanical energy in the event of a smartphone falling or foreign objects falling on the screen module. Therefore, the entire load falls on the tempered glass of the screen module.

protective film

The protective film also cannot boast of wear resistance. Contact with metal and plastic objects leaves small and large scratches noticeable during a cursory inspection. Scratches on the matte film are less noticeable, due to the rough and uneven surface. In addition, sharp objects can easily cut the film.

The hydrogel film in combination with polymer materials allows you to tighten small scratches after a certain time. At the same time, the film is also not able to boast of special protective capabilities.


Do screen protectors really work?

Yes, the screen protector really works. Tempered glass screen protectors work effectively, reducing damage from drops and scratches. Protective films also allow you to protect the screen. However, protective films do not protect the screen when it is hit or dropped from a height.

How does liquid screen protectors work?

After a liquid protective film is applied, a thin protective layer is formed on the surface of the screen. Some protective coatings give the screen an oleophobic property. And the applied chemical compound allows you to reflect the contact of some blunt and sharp objects.

Is a screen protector necessary for iPad?

A protective cover will help protect the screen in everyday use. If you use your tablet carefully, you can do without the screen protector.

How does a nano screen protector work?

Just like the liquid screen protector. See above.

How effective is nano screen protector?

Its protective properties are significantly inferior to tempered glass and film. At the same time, some compositions from which nano glass is made allow you to give the screen oleophobic property. Thus nano screen protector works better as a means of preserving the good appearance of the screen than a way to protect it from shocks and damage.

Is tempered glass screen protector worth it?

Tempered glass provides the best protection for your screen. The tempered glass helps protect your screen from impact if it is dropped. It also prevents scratches on the surface of the screen.

Do tempered glass screen protectors work against drops?

The tempered glass helps protect the screen when it is dropped. However, in some cases, the impact may be too high, which may cause the glass to break.

Can glass screen protectors damage your phone?

Tempered glass cannot damage your smartphone. Therefore, you can use any tempered glass without any problems.

Are screen protectors worth it 2021?

We think it’s worth it. Although in the top phones manufacturer phone glass is strong enough, but additional protection in the form of tempered glass does not hurt. Protective plastic foils have low protective properties, and the cost is comparable to tempered glass. Therefore it does not make sense to buy a plastic film instead of glass. At the same time, fingerprint scanners built into the screen may not work with glass, but with the film they work without problems.

Which is better plastic or glass screen protector?

Glass with a combination of polymers is stronger than conventional glass. However, there are not many such protective coatings on the market.

Do glass screen protectors break easily?

It all depends on the applied force or force of impact. Usually tempered glass rarely breaks and lasts 2 to 3 years.

Can you restick a glass screen protector?

You can reinstall the protective coating several times before the adhesive base is damaged.

How long does a glass screen protector last?

In normal use, stable 2-3 years. In places with dry and sandy climates, 3-6 months.

When should you replace your glass screen protector?

The glass can be replaced when there are deep scratches, cracks and chips. As long as the glass is not worn or damaged, you do not need to replace it.

Which type of screen protector is best?

The best screen protector is tempered glass. Glass provides effective protection due to its high strength and durability.


The article describes how tempered glass and protective film work. Thermal or chemical hardening increases the strength of the glass, which allows you to absorb more mechanical energy. And the increased thickness relative to the film contributes to wear resistance in contact with metal and plastic objects. The film is not able to absorb a significant amount of mechanical energy due to the thickness of a couple of hundred microns. Therefore, the most effective protective coating copes only with non-sharp plastic and metal objects.

What questions do you have? Leave messages in the comments below the article.  

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About the author 

Alex Gustman

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