The industry overview of cover glass

1.The definition and application

 

The cover glass, also called cover lens is the transparent protective layer outside of touchscreen. There are several responsibilities: Resists scratches, anti impact, light pass and decroation.

You will find it applied in:

Consumer electronics(phones, tablets, smartwatches)
Automotive displays(center consoles, instrument clusters)
Medical devices, industrial terminals, building facades, and more

 

2. Main material types

Classified by chemical composition and strengthening method:

Soda-lime glass - Low cost, average performance. Used in budget products.

High-alumina glass (like Corning's Gorilla Glass) - Chemically strengthened. Surface compressive stress (CS) above 700 MPa, depth of layer (DOL) over 100μm.

Lithium-aluminosilicate glass - Uses two-step chemical strengthening to boost both CS and DOL at the same time. Better drop resistance.

Glass-ceramics - Newer material. Better impact resistance than traditional aluminosilicate glass. More Chinese phone brands are starting to use it.

 

3. Typical manufacturing process

For 2D or 3D cover glass, the usual steps are:

Raw material selection - Ultra-clear or high-alumina glass sheets, 0.4 to 2.0mm thick.

Cutting and CNC shaping - Cut to size. Complex shapes (like 2.5D curved edges or camera holes) need high-precision CNC to avoid edge chipping.

Lapping and polishing - Remove burrs, smooth out the surface.

Chemical strengthening - Ion exchange in a potassium nitrate bath. Creates a high CS layer, pushing hardness up to 7H.

Cleaning - Ultrasonic bath to remove fine dust.

Screen printing - Add logos, bezels, etc. Machine-printed, alignment tolerance around ±0.02mm.

Ink curing - Bake to bond the ink firmly.

Surface treatments - AG (anti-glare), AR (anti-reflection), AF (anti-fingerprint).

Inspection and packaging - Check optics, dimensions, strength.

One more thing: 3D cover glass requires an extra hot-bending step (700–750°C, using graphite molds).

 

4. Key technologies and innovations

Multi-station screen printing - A 2026 patent from Hunan Hewell Photoelectric (CN224159066U) uses a clamping plate with spring adjustment to fit different glass sizes, improving print accuracy.

Vision alignment systems - Automates printing, replaces manual work, significantly improves yield.

Ultra-thin flexible glass - Down to 0.03mm thick for foldable displays. Requires extremely precise thinning technology. Heilongjiang Jintai Photoelectric is a domestic leader in this space.

Integrated processing - Combining cutting, CNC, printing, and inspection into one workflow to boost efficiency.

 

5. Industry landscape and trends

High market concentration - Lens Technology and Biel Crystal are the two Chinese giants, together taking up most of Apple's and Samsung's supply chain.

Domestic substitution is accelerating - Companies like CSG Holding, Iris Group, and Xuhong Optoelectronics have made breakthroughs in high-alumina substrates, getting closer to international standards.

Technical barriers – Raw glass production is both technology- and capital-intensive. Foreign companies like Corning still dominate the high end. Midstream processing is more about scale and yield.

Where things are headed -

Thinner and flexible (foldable displays)

Smarter and more customized (AR/VR, automotive)

More automation and digitalization