Tempered glass and PET film for OEM screen protection:
when to choose which

One of the most common questions we get from engineering and procurement teams new to custom screen protection is which material to specify — tempered glass or PET film. The honest answer is that both have legitimate uses, and the right choice depends entirely on the device, the environment, and what the protector is actually being asked to do.

This article walks through both options in OEM-relevant terms. We supply both. We're not trying to push you toward one or the other — we're trying to make sure the specification you put on the RFQ is the one that fits your application.

What each material actually is

Tempered glass

Tempered glass screen protectors are thin sheets of chemically or thermally toughened glass, typically 0.2mm to 0.5mm thick, with an oleophobic coating on the user side and a silicone adhesive layer on the device side. The glass itself is usually rated to 9H surface hardness on the Mohs-adjacent pencil hardness scale, meaning it resists scratching from anything softer than corundum (and most things in a pocket or on a shop counter are softer than corundum).

Tempered glass is rigid. It feels closer to the original device glass under finger touch. It can be precision-cut to fit curved or notched displays. When it fails, it tends to fail by cracking — which is by design: the protector takes the impact instead of the device screen.

PET film

PET (polyethylene terephthalate) film protectors are thin, flexible plastic films, typically 0.1mm to 0.2mm thick, with a hard top coat for scratch resistance and a silicone or acrylic adhesive layer. The hardness rating is lower than glass (typically 3H to 5H) but the flexibility means the material absorbs impact differently — it deforms rather than shatters.

PET is light, almost invisible on the device, and tolerates flexing. It's commonly used where the underlying display itself is flexible, where shatter risk is unacceptable, where weight or thickness matter, or where the protector needs to wrap around a curved edge.

When tempered glass is the right choice

Tempered glass is generally the better fit when:

• Scratch resistance is the dominant concern. Retail counters, POS terminals, shared device fleets where the screen sees keys, coins, badges and unidentified hard objects.
• Touch feel matters. Consumer-facing devices where the user expects the protector to feel like part of the device, not like an aftermarket sticker.
• Optical clarity is critical. High-resolution displays where any haze, distortion or rainbow effect would be noticed — medical imaging displays, design tablets, premium consumer hardware.
• You want predictable failure. Glass cracking is a clear signal that the protector has done its job and needs replacing. Film damage is often more ambiguous.
• The device is flat or only mildly curved. Glass can be made to fit a 2.5D edge but it has limits — extreme curves and folds are PET territory.

When PET film is the right choice

PET is generally the better fit when:

• Shatter is unacceptable. Aviation cockpits where loose glass fragments could end up in equipment. Food preparation environments where contamination from broken glass would be a serious problem. Medical environments where shattering near patients is unacceptable.
• Weight and thickness matter. Wearables, ultra-thin tablets, devices where every gram counts.
• The display curves significantly or folds. Foldable phones, wraparound displays, devices with prominent curved edges — glass struggles, film conforms.
• Impact absorption matters more than scratch resistance. Some industrial environments see more drops than scratches.
• Cost-per-unit is a primary driver and the application is non-critical. PET is typically less expensive per unit than equivalent glass, and for some bulk applications that matters more than the marginal hardness advantage.

Side-by-side comparison

Attribute	Tempered glass	PET film
Surface hardness	9H	3H–5H
Typical thickness	0.2mm–0.5mm	0.1mm–0.2mm
Touch feel	Glass-like, premium	Slightly plasticky, lightweight
Optical clarity	Excellent (≥91% transmission typical)	Good (≥88% transmission typical)
Shatter risk	Cracks under heavy impact	None — flexes instead
Curve / fold tolerance	Limited (flat or 2.5D edge)	High — wraps and folds
Typical unit cost	Higher	Lower
Replacement signal	Visible cracking	Surface marks, harder to assess
Weight	Heavier	Negligible
Best for	Retail, medical displays, premium consumer	Aviation, foldables, wearables, food prep

Hybrid and specialist variants

Beyond plain glass and plain PET, several hybrid material options exist that solve specific application problems:

TPU (thermoplastic polyurethane) film

A self-healing flexible film that can recover from minor scratches over time. Useful for devices where scratch resistance matters but PET's marginal hardness isn't quite enough, and where glass is unsuitable for shatter reasons.

Glass with TPU sublayer

Tempered glass bonded to a TPU layer combines the surface hardness of glass with the impact absorption of film. Used in rugged industrial tablets and military applications.

Anti-glare matte finishes

Available on both glass and PET. The matte coating diffuses reflections, useful for outdoor industrial use, cockpit displays, and any environment with strong overhead lighting.

Privacy filters

Micro-louvre layers that restrict the viewing angle. Available on both glass and film. Critical for any device displaying confidential information in public — healthcare, finance, government workstations.

Anti-blue-light coatings

Available on both materials. Filter a portion of the blue-light spectrum. Relevant for devices used for extended viewing periods.

The question to ask before specifying

If you take only one thing from this article, take this: don't specify the material before specifying the failure mode you're trying to prevent. The order of questions should be:

1. What environment will the device be in?
2. What's the most likely cause of screen damage in that environment — scratch, impact, contamination, glare?
3. What would constitute "failure" of the protector — a visible crack, a noticeable scratch, a privacy breach, a regulatory non-compliance?
4. Given those, which material is engineered for that specific failure profile?

This is the conversation we have with OEM partners at quote stage. The material spec falls out of the application analysis, not the other way around.