HOW IT WORKS
Explained: flexible displays
It seems as if 2020 will be the year of the fold and the roll. Motorola’s rebooted Razr phone comes with a foldable display and a price of around £1,500, while Samsung’s Galaxy Fold has a bigger screen and price tag: it’s £1,800. Both the screen and its price fade into insignificance next to LG’s OLED TV R9 – a 65-inch 4K TV that rolls away completely and will cost an estimated sixty thousand dollars.
How do you make a display that folds? With some difficulty. We’ve been promised flexible, foldable displays for years but it’s taken a long time for them to become practical. Part of that is because we had to wait for OLED.
OLED (Organic Light-Emitting Diode) displays differ from traditional LED displays because each pixel produces its own light. In non-OLED displays, the pixels don’t: LEDs produce a backlight which is projected through them and onto the screen, which is usually glass. Even the cleverest smartphone glass is not currently famed for its flexibility. Not only that, but the backlight would make things harder because it also has to flex – and it has to flex in a way that keeps the light to the pixels consistent. It turns out that trying to achieve that is a real pain in the glass.
OLED takes that pain away, because you can print the OLEDs onto a sheet of plastic – and plastic bends. The iPhone X used “innovative folding and circuit stacking technology” to bend the edges of its display into the corners and software to remove visual distortion – but only to a very limited extent.
Remember the Royole FlexPai? Most people don’t, but it was the first commercially available phone with a folding display. It was revealed in late 2018, it used a plastic OLED and it was absolutely awful.
Reviews described the “blotchy and slightly rough” texture, the “cheap” and “tacky” and very thick case, and the “mediocre” cameras. As our friends at TechRadar wrote, it was “pretty terrible”… “a glimpse of how smartphones with bendable screens will work” rather than a product any sensible person would want to buy.
More attempts
Surely Samsung would do a better job? Surprisingly, no. When Samsung made its own foldable phone, the Samsung Galaxy Fold, it apparently forgot to test the quality of the folding bit. In April 2019, it was forced to delay the launch because reviewers found that the display on some of the £1,800 devices failed after just a few days’ use. The device has since been slightly redesigned and relaunched.
There were multiple reasons for the first Galaxy Fold’s lukewarm reception. Its screen is softer than a glass one and susceptible to dents and scratches – Samsung now warns users not to tap the screen too hard – and the original hinge design made it too easy for dust to get in and damage the display. The original also shipped with a thin plastic film that looked like a screen protector but wasn’t, and removing it could break the screen.
Trying to achieve flexible dipslays is a real pain in the glass
The 2020 Razr has attracted lukewarm reviews too, with reviewers noting the flimsy hinge and the pronounced groaning noise it makes when you open or close it. BBC Click demonstrated that you could quite easily lift the screen away from the rest of the device, which suggests it’s going to be prone to problems with dust and dirt.
When to fold
The problem with folding screens is very simple: they fold. Because they fold, they have moving parts and are subject to stresses and strains. That means they have a limited life expectancy: Motorola says its new Razr should last around two years in normal use, but an automated folding test by CNET broke one after 27,000 folds. That’s the equivalent of six to 12 months of everyday use. The Samsung coped better, breaking after 120,000 folds, but that’s still short of the 200,000 folds Samsung promises. LG’s TV, which rolls rather than folds, is expected to last through 50,000 unrolls. Given the problems in making them and the cost of buying them, why would anybody want a flexible display?
There are lots of reasons why flexible displays are worth waiting for. Portability – imagine an iPhone that could double in size, or one that could fold to fit even the smallest pocket – and in the case of rollable TVs, it’s handy to have a giant TV that isn’t there when it isn’t in use. In the longer term, the benefit comes from having the ability to have opaque or transparent displays in any shape or size. You could have a display in a pair of sunglasses, wrapped around your wrist, stretched across the contours of your car’s dashboard or encircling you at work or when you’re gaming.
So what kind of flexible display is Apple working on? That’s a very good question. Apple’s patents include one for a display that folds in the middle and one for a display with two foldable regions, enabling you to fold it once and then fold it again in the shape of a capital G; one for a magnetic latch that would keep a folded phone closed without a physical lock; one for a flexible battery with graphite padding to help dissipate the heat of the battery and display; and one for a heating element that would stop a folding display from being brittle in really cold weather. And Apple is reportedly working with a new, flexible kind of glass from smartphone glass innovators Corning. So it’s definitely up to something.
That something might not necessarily be limited to a folding phone. Apple has also patented the use of a flexible display that would incorporate buttons, microphones and speakers: one part of the display would act as a speaker, another as a pressure sensor and so on. Unlike our existing phones, we’d actually feel the screen respond to our pushes – so an on-screen button would feel like pressing a real one. Such a display would also remove the need for a large notch cut into the main display area because it wouldn’t need space for the top speaker.
You won’t see these changes in the iPhone 12. Flexible screens are still very much in their infancy, and you can see why the most flexible display Apple currently uses is the one in the current iPhones. As ever, Apple is content to learn from the mistakes other manufacturers are making: why rush to be the first when you can wait and be the best? Carrie Marshall