How do new folding phones work?

It’s often said there’s nothing new under the sun, and the current excitement about folding phones is a case in point.

Folding phones were ubiquitous twenty years ago, with iconic models like the Samsung A800 and Motorola Razr proving hugely popular among style-conscious consumers.

And now they’re back. But this time, there’s a twist.

Instead of having a diminutive front-facing display preceding a larger internal screen like their Millennial forefathers, today’s models have screens which fold.

That requires some highly sophisticated engineering, which has so far delayed the rollout and adoption of folding handsets.

Yet the long-awaited folding phone revolution is finally here, with two new models launched in February and plenty of others in the pipeline.

Return to the fold

The A800 and first-generation Razr had twin screens divided by a section of the phone’s chassis, with internal hinges supporting a flip mechanism.

When the screen itself is foldable, more complex solutions are required.

The compact Samsung Galaxy Z Flip opens out to reveal a 6.7-inch display – the size of a high-end conventional smartphone in a pocket-friendly package.

It uses an OLED panel behind a very thin layer of glass, while the 1.1-inch outer display is ironically reminiscent of Millennial handsets, showing notifications and the date/time.

The Z Flip’s screen can be positioned at any angle. At 90 degrees, the top half acts as a viewing area while the bottom half provides touch controls.

Motorola’s reborn Razr adopts similar principles of vertical opening, whereas the Huawei Mate X (not yet on sale in the UK) opens horizontally to create an eight-inch tablet.

While folded up, it has a 6.6-inch front-facing screen and a 6.4-inch rear-facing panel that can double as a selfie mirror.

Microsoft has gone even further. Its Surface Duo incorporates a pair of 5.6-inch displays which can be combined or rotated 360 degrees, and operated independently of each other.

Some handsets have a visible hinge down the middle, whereas others like the Royole FlexPai are almost seamless, continuing to display content around their fold at any angle.

Some fold outwards and others fold inwards. Even so, the full-screen effect is impressive on any device, and stunning on some.

Is this a gimmick?

Public opinion remains divided.

There’s no question that these devices look great when unfolded, but they’re quite chunky in their folded state. That makes them heavy, as well as expensive.

And while web content and streaming media files look magnificent on what’s effectively a tablet screen, most mobile apps have been designed for screen rations of 19:9 or even 20:9.

Display issues are likely to be a problem for some time, especially as there’s no industry standard in terms of folding screen ratios or dimensions.

Finally, despite intensive lab testing, it remains to be seen how robust these devices are. One press reviewer reported their first-generation Samsung Galaxy Fold was broken within a day.

Such issues caused the Fold’s consumer launch to be significantly delayed. Huawei then panicked and pushed back the launch date of their folding Mate X handset twice.

It remains to be seen whether a display screen can cope with being folded out thousands of times in real-world conditions, without warping or pixelating.

Even so, there’s no doubt that a folding phone provides early adopters with a wonderful sense of one-upmanship when they use their device in public.

It’s very much a personal decision whether the benefits of folding phones outweigh the uncertainty surrounding this new (and relatively untested) technology.