PET, TPU, or Tempered Glass – all you need to know to choose a screen protector

A bit of a disappointment in the past, today's screen protectors are easier to install, cheaper, and better than ever in every aspect. There are three varieties - PET film, TPU (polyreuthane), and our undisputed favorite - tempered glass. And then there are two methods to get them on your display – dry and wet. So here's more about how screen protectors work and what they offer.

PET Film

Obviously, PET doesn't stand for a dog or a cat. It means "polyethylene terephthalate" - a type of plastic that's available in many variations depending on specific applications. In the manufacturing industry, it's used for mundane stuff like liquid and food containers. But this doesn't mean that PET film protectors are glorified water bottle plastic. They consist of polyester film with a scratch resistant matte coating on one side and a silicone adhesive on the other. Quality ones are quite clear and add a functional anti-scratch layer to your screen, but have no impact protection. And their scratch-resistance isn't better than what Gorilla Glass already has - it's limited to fingernails, coins and keys. They are cheap, and usually come in packs of three or more. Their downside is that plastic is the easiest to discolor from sun rays and oil buildup from your fingers, and it doesn't feel as nice as glass does to the touch.



If you have a cheaper or older phone, or you're fine with the most basic and affordable screen protection, get a PET protector. The manufacturer doesn't really matter, but if you have a soft spot for a particular brand, there's no reason not to go with theirs. Chances are that protectors from established brands will be better cut-out for your device and won't leave loose edges that can catch on to your clothes and peel the protector away (it has happened before).

TPU

TPU (thermoplastic polyreuthane) is next in the screen protector food chain. This is chemically-enhanced plastic whose properties include scratch resistance, elasticity, oil and grease resistance, and increased toughness. Since the material is elastic, it has limited "self-healing" abilities. This means that its slight softness gives it the power to absorb non-extreme impact, such as most drops and lighter scratches, while retaining all or most of its original composition. For example, lighter scratches usually leave just a small dent in the soft plastic, which slowly returns to normal.



The "military-grade" tag most TPU protectors proudly carry is worthy of an explanation. One manufacturer says that this material is used "to protect jetfighters". And what do you know, it's true! Skim through this Aerospace Surface Protection brochure - it's full of polyreuthane protective tapes used for "aircraft and windmill leading edge protection". However, getting a TPU case or screen protector doesn't guarantee it's made of the same quality of material. But your smartphone also isn't a fighter jet, right?



If you are willing to pay a slightly higher price, a TPU protector is, logically, better choice than PET film. At the very least, it's going to provide better impact protection (although you shouldn't be pushing your chances). It's also nicer to the touch, although it isn't glass-smooth. Arguably, the best part is that you'll get to explain to your friends and acquaintances how your phone has "fighter jet protection". Pretty cool, huh?

Tempered glass

Protection with a temper! Tempered glass (TG) screen protectors are the absolute best you can buy. Material-wise, a high-quality TG protector is multi-layered, usually starting with shock absorbent silicon on the bottom layer, followed by PET film optically clear adhesive to sandwich together the previous two layers and the next two, which are tempered glass and oleophobic coating. All of this scratch, oil, and shock protecting goodness is compressed into a <0.4mm-thick sheet that's no harder to apply than a PET or TPU protector, and not heavier or otherwise obnoxious.



A glass protector is superior to its alternatives in every way. It has better light transmittance, making for a clearer display. It's anti-reflective and glare reducing. It has oleophobic coating, which heavily reduces fingerprints. It has the smooth feel of actual glass under your fingertips. Unlike Gorilla Glass 3, it resists sand scratches, making it the only viable option for beachgoers. And let's talk about shock protection. T-glass protectors boast a material hardness rating of 8H to 9H, meaning they are hard enough to resist scratches from anything that's not topaz or corundum (extremely hard aluminum oxide). Yet, they aren't completely shatter-proof. Since this is toughened glass we're talking about, in the event of a fatal drop, the protector will absorb all the damage and break into tiny shards. Chances are pretty good that your display will end up unscathed underneath. Thus, instead of having to replace the entire screen, you'll only have to get a new protector. Which is easier on both your soul and your wallet.



As you probably expected, tempered glass protectors are the most expensive kind. Most renowned brands can charge up to $40 for their products. And although that's money well spent if you are rocking an expensive flagship smartphone, excellent tempered glass protectors can be found for less than $15 online.

Dry vs Wet Mount

There are two methods for installing a screen protector - dry and wet. The method is usually specified on the box.

The dry method keeps the protector glued to the screen with static electricity. There's no adhesive involved, and the application is very straightforward. In short, you're supposed to enter a dust-free environment (either outside, or in your humid bathroom, preferably naked to prevent dust specs from your clothes), clean your phone thoroughly, align the protector and apply it. After a few tries, you will end up with near-perfect results. You don't have only one shot at this. Most dry-application protectors will let you carefully lift them off the phone and take care of misalignment and dust particles before trying again. Some even come with an electrostatic paper band to help you get rid of annoying dust.

The wet application method works by spraying liquid on the underside of the screen protector. It's a convoluted and awkward ordeal. You're tasked with the very precise placement of a thin, wet sheet of plastic - quite frustrating, because the liquid adds weight and gets the protector folding and dancing in every direction but the right one. Allegedly, wet protectors are easier to place without forming air bubbles or trapping dust, and are more resistant to peeling. If you mess up the installation at first, they too give second chances at applying them correctly. But all the phone drying, protector re-moistening and getting rid of excess liquid between it and screen is quite the patience test.

Wrap-up

With so many options available, and at very fair prices, getting a screen protector for your device has become a no-brainer. PET film products are the best choice for basic screen protection. TPU protectors can be a bit rare, but they have the best ratio of affordability and toughness. Finally, Tempered Glass protectors offer the ultimate in protection and feel, but they are the priciest of the bunch. Still, even the most expensive ones make sense for flagship smartphones and tablets.



references:

Wikipedia – Toughened glass , Thermoplastic polyurethane , Liquid optically-clear adhesive

Types of screen protectors

Material hardness table

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