Galaxy Fold's bendable screen is still flawed. Is diamond glass the solution?

One company is pursuing the idea of making bendable phone screens from one of the hardest materials on Earth.

Jessica Dolcourt Senior Editorial Director, Content Operations
Jessica Dolcourt is a passionate content strategist and veteran leader of CNET coverage. As Senior Director of Content Operations, she leads a number of teams, including Thought Leadership, Speed Desk and How-To. Her CNET career began in 2006, testing desktop and mobile software for Download.com and CNET, including the first iPhone and Android apps and operating systems. She continued to review, report on and write a wide range of commentary and analysis on all things phones, with an emphasis on iPhone and Samsung. Jessica was one of the first people in the world to test, review and report on foldable phones and 5G wireless speeds. Jessica led CNET's How-To section for tips and FAQs in 2019, guiding coverage of topics ranging from personal finance to phones and home. She holds an MA with Distinction from the University of Warwick (UK).
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Jessica Dolcourt
5 min read

A foldable phone screen made from glass is only a matter of time.

Angela Lang/CNET

Foldable phones  like the Galaxy Fold have a big problem -- the screen. Today's phones use plastic cover materials, but bendable glass is the Holy Grail of foldable phone design because of its ability to repel the damage from casual scrapes sustained by polymer. Without a rigid top layer, the phone's internal workings are susceptible to breaking. One company I spoke with last week at CES thinks it's found the answer: diamond glass.

Turns out, keeping the delicate, flexible electronic display beneath the surface safe from pressure, water, dust and sharp objects is difficult when you don't have a hard material to protect it.  Samsung  bore the brunt of this reality when its  Galaxy Fold  sustained several types of screen damage before the Fold officially went on sale.

But diamond glass is hard, said Adam Khan, founder and CEO of Akhan Semiconductor, which is developing Miraj Diamond Glass, and will be completely foldable. "Nano-diamond is actually semiflexible by itself, and we can coat flexible glass," said Khan.

Miraj Diamond Glass is a material made from lab-manufactured nano-diamond materials. It's sprayed onto a surface in a layer that measures just 100 nanometers, or 1/10,000th the thickness of a strand of hair. Diamond glass can coat either a plastic (polymer) sheet or a slip of untreated bendable glass.

Motorola Razr Foldable Flip phone

Foldable phones like the Motorola Razr use plastic screens and reveal a crease at the bend. 

James Martin/CNET

With their high prices and untested designs, foldable phones are a tough sell as is. A strong cover material to protect against drops and scratches could help shift foldable phones from expensive curiosities to serious products that could one day replace your traditional shingle-shaped phone.

Akhan Semiconductor isn't the only company working toward a stronger material for foldable phones. Gorilla Glass-maker Corning showed CNET glass that's thin enough to fold without breaking, but it's still in development and isn't commercially available. 

If it were, we'd see a lot more foldable phones today. Without a ready supply of glass thin enough to fold in half and strong enough not to crack, splinter or break, device-makers have had to choose whether to wait for a new material or work with what they have.

Watch this: The bendable glass that’s shaping up to cover foldable phones

Diamond versus plastic: Is it all it's cracked up to be?

Apart from being one of the strongest substances on Earth -- diamond glass reportedly withstood lasers in a recent demo with Lockheed -- diamond crystal might not suffer the same unsightly screen creasing that appears where the Galaxy Fold, Huawei Mate X and Motorola Razr screens bend in half.

"It's a conformable coating, so you won't lose any of that foldability. Things that we've heard from the OEMs are that they would actually like it because the [typical] glass as it is isn't strong enough in a foldable context, so this should really go toward strengthening that structure," Khan said.

Miraj Diamond Glass is also designed to coat a foldable phone's chassis, so manufacturers may not need to use heavy, cumbersome steel reinforcements within the device to support a superthin screen on top. 


Miraj Diamond Glass looks like regular glass, but it's treaded with a nano-coating of diamond crystal.

Akhan Semiconductor

The material also repels water and surface oils without needing an additional oleophobic coating typical of phone materials like Gorilla Glass, Khan said. In addition, diamond glass dissipates heat to keep phones running cooler, which in turn could extend the battery life of devices that use this substance.

Here's the clincher: Khan says his company won't charge more for a diamond glass treatment than Corning would for Gorilla Glass. Khan didn't reveal pricing and Corning did not respond to a request for comment.

Still, there may be reason for some phone-makers to pick plastic over glass. Naysayers point out that diamond glass and sapphire crystal, another substance that's been known to cover iPhone camera lenses, might be strong, but could also be more brittle than Corning's chemically strengthened Gorilla Glass.

Plastic can also be treated, like the hard coating Motorola chose for its foldable Motorola Razr .

"When glass fails, it shatters. When plastic fails, it scratches," said Tom Gitzinger, director and principal engineer of innovation and architecture for Motorola , when I went to see the Motorola Razr in Chicago ahead of its official November launch. 

Motorola gained experience working with a hardened plastic topcoat for its Shattershield cover material on previous Motorola Droid phones, like 2017's Moto Z2 Force, which tore, but didn't break, after I dropped it 28 times.

Diamond glass in 2021, but haven't we heard this one before?

This is not the first time I've sat across from Khan in a nondescript Las Vegas hotel room. CES 2017 was my first introduction to Miraj Diamond Glass. Three years ago, a confident Khan promised that we'd see a phone protected by diamond glass by the end of that year. At CES 2018, he pushed the goalposts back to the end of 2019, but averred there was an exclusive phone-maker on board.

Now, at the dawn of 2020, Khan and I met again face to face. Perhaps a little more salt streaked his loose black hair, perhaps his voice was a little quieter in the stillness of the otherwise unused room. But Khan's cheery confidence remained.

I had to ask, what happened to those promises? Is diamond glass real, and what about the application with foldable phones? 

Motorola Razr is a foldable flip phone like you've never seen before

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The holdup was two-fold, he said. The quality wasn't quite there, which sent the company back to fine-tune the product. Then the exclusive partnership fell through.

"There's been some changes in the OEM world and certain partners we were moving to be with are no longer -- they were in the space and then they dropped out, so we haven't picked on to cross the line yet, but we're still working with the vast majority of the OEMs," Khan said. 

Producing enough diamond glass to cover a large volume of phones is also a challenge, but one Khan thinks he's found a way around the issue by working with a glass substrate, or sub-layer, that an OEM has already ordered -- instead of trying to coat a smaller subset of glass or plastic panels in-house.

"You can't order 100, you order millions," he said.

As for foldable diamond glass, the company is still a ways away. Miraj Diamond Glass won't be ready for a flexible glass demonstration until the next generation.

So even if Akhan Semiconductors does secure an exclusive phone partner by the end of 2020, and even if we don't see that phone until 2021, a diamond glass screen on a foldable phone could still trail flexible glass by years. Even so, it'd be a brilliant test of strength that I, for one, am raring to see.

Originally published earlier this week.

Phones at CES 2020: Cheap, shiny, 5G and concepts

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