What is the future of mobile phones that can be folded? We have heard about how flexible the display will be for the future of smartphones and tablets, far from 2013, when Samsung showing off his ‘Youm appearance at CES but not until last year we have to see such a display in an actual product that is not just a concept.
But in a short span of time, the display technology that can be folded seems to have been quite mature LG even make Rollable TV last year, which was in the spotlight at CES 2019. While all of this is good, the foldable OLED screens are smooth on their own, which means they still need a protective layer on top if they have to be used in the real world. , like on a smartphone. For this, we need a bendable glass.
Up to now, all of the folding phones that we have seen have used a plastic protective film over the OLED panel for basic scratch protection. However, this is clearly not enough for long-term or even short-term durability. Just take it Samsung Galaxy Fold from last year, who failed miserably in the endurance test. That Motorola Razr (2019) also has several failure reports, from screen is messy within one week of using the Internet hinges give up after only four hours open it open and close.
The first cellphone to use a folding glass screen is this year Samsung Galaxy Z Flip. Certainly feels like the real deal when we are try it for the first time at the launch event, without any tangible signs of appearance being fragile or delicate. However, it turns out that this isn’t even as sturdy as ordinary scratch resistant glass at this time and in one endurance test fared as bad as Galaxy Fold and Motorola Razr (2019).
The Samsung Galaxy Z Flip is the first globally available folding smartphone that uses a glass screen
The challenge in making folding glasses
Folding glass or ultra-thin glass (UTG), such as those used in the Galaxy Z Flip, is still the first generation product, which means it still has a long way to go before it can last as long as it is used on ordinary cellphones today, while still being flexible.
“Thickness is the main difference between flexible and traditional flat glass, besides some” magic ingredients, “said Mathias Mydlak, Global Business Development Manager at Schott.
Bendable glass is basically glass that has been stretched quite thin and then treated so that it can be bent back and forth, without losing its shape permanently. However, making thin glass to the point where it’s flexible is the biggest challenge, according to Mydlak. “We define Ultra-thin glass (UTG) to reach a thickness below 0.1 mm,” he added.
Schott claims to have used UTG glass for other applications since the last few decades and has a specially developed lottery process. ‘Here, the glass band is pulled from the top, moving across various drums and through the cooling path to get the final product.
Schott is one of the few glass manufacturers who already have flexible glass solutions on the market. Samsung is one of its clients, which means that the UTG glass on the Galaxy Z Flip is most likely provided by Schott. Corning is also believed to be working with device makers to implement their own solutions. “We are working with our customers on this challenge and are currently taking samples of our development glass with them to optimize products for their design requirements,” said a Corning spokesman.
Foldable glass must be able to handle constant creases and folds to make it a viable solution
Photo Credit: Schott
Is it durable like ordinary toughened glass?
So far, it seems not so. If we take the Galaxy Z Flip as an example, the endurance test of the popular YouTube channel reveals that UTG glass is scratched easily as a plastic screen on Galaxy Fold and Motorola Razr (2019). In fact, the strong indentations made by finger nails also appear to leave permanent marks on the screen.
Schott argues that the scratch resistance of foldable glass is in the same range as ordinary glass which is thicker and all depends on the hardening process. “The hardening process is carried out by a separate glass processing company. Therefore, ultimately it depends on the steps and recipes of each processing, “Mydlak said. This means, even though Schott or Corning might provide raw materials, the toughness or durability still depends on the type of care provided by the cellphone manufacturer, for now.
Corning on the other hand believe there is still a lot of work to be done before folding phones are as durable as usual. “In general, we believe the choice of plastic material sets and glass options currently do not meet all the desired attributes of a bendable device,” said a Corning spokesman. However, Corning states that folding technology has shown success in the thickness range of 30-100 micrometers in R&D.
Besides being able to withstand scratches, the biggest resistance to folding glass is its ability to maintain its structural integrity even after years of folding and opening. Corning claims that the glass-based solution he developed can bend more than 200,000 times without damage while maintaining its flatness. Meanwhile, Mydlak stated that the life of a foldable glass ultimately depends on the final design and processing carried out by the device manufacturer.
Both Corning and Schott invested heavily in R&D for folding glass solutions
Photo Credit: Corning
Another problem commonly found on foldable devices is the folds that are visible on the fold, which are natural but also reduce the feeling of having a completely flat screen. Although this has more to do with the actual folding screen panel itself, with phones like now having glass covers, it is important for glass to have minimal folds as well, if any.
“We have seen that the fold has decreased after switching from a polymer film substrate to UTG as a premium substrate. This is actually strong evidence of the ability of this material class, “Mydalk said.
Making folding glass is also arguably more expensive than ordinary glass of the same size. Although Mydalk doesn’t comment on how much more expensive it is, he said the two could be at the same level at some point in the future, provided that enough people buy a device with folding glass.
We don’t expect foldable technology to become mainstream in the near future but that doesn’t mean it won’t happen. There was a time, not too long ago, when even top-selling cellphones came with only one camera and today, most of us won’t even see a cheap cellphone if you don’t have at least three cameras, and it’s only on the back.
“As new developments or technology advance, all players are eager to assess growth trends and consumer preferences,” Mydalk said. “As it is gaining popularity and we are seeing mass demand for folding glass, the product will automatically become more cost effective and easily accessible,” he added.