What Are LCD Screen Protectors?

LCD screen protectors are made of thin polyurethane films. They have to sustain heavy abuse. We scratch them, rub them, expose them to bright sunlight and high temperatures. We all need one especially for our mobile devices. No one wants to replace their phone's screen every month.

The important physical property of screen protector is viscoelasticity. The film has to be out of elastomer. For end-user this means it is elastic and does not break. You can tear it, pull it out of shape but you can not break it. Although it is reliably thin (usually 0.008 inch) due to elasticity it can protect your screen cover from braking apart on impact. That's because elastomers are able to absorb large amounts of kinetic energy.

Most of what the protective film is made of can be found around you at any time. Oxygen, hydrogen, nitrogen, carbon, all of which are found in air and water around us. Off course for industrial purposes that they are acquired from other sources. It takes too much energy to break up water into oxygen and hydrogen.

Other ingredients of the recipe for a protective film are more complex and depend on the producer. They are usually company's secret and have three main objectives. The film must not lose elasticity with time. This is associated with polymer swapping capacity and it is an important issue that has to be addressed. You might have noticed, when the corners of your protective film pill of them become hard and they shrink. It usually takes only a few days once the process starts. That's because polymers dry out, they become hard and breakable and useless as screen protectors.

The other two objectives the producers are trying to meet are:

  • not to reflect light, which is commonly refered to as anti-glare coating
  • and adding anti-static properties or more specifically trying to limit polymer's ability to cumulate electrostatic energy. Both are applied in a form of coating.

In the end we have a very smart product. It is elastic and has a bit of glue on one side which makes it very easy to install on the device. Because it is light and thin it does not disturb you when you use the device. Glue and large surface rise friction so it does not come off. It has anti-glare and anti-static coating and it's very cheap so you can replace it every few scratches. It's a brilliant thing.