Foldable phones and the search for a reason to fold
iPhone Duo features a 7.6-inch inner display that provides a large canvas for viewing content, gaming, and multitasking. Closed, it’s similar in size to a passport with a 5.4-inch outer display (images: Apple)
I once owned an LG flip phone. Opening it to answer a call and snapping it shut afterwards felt gratifyingly purposeful.
The hinge made the phone smaller, protected the screen and provided a satisfying end to every conversation. Nobody wondered why the phone folded. Its form served an obvious function.
Apple’s new iPhone Duo also folds, but for a less straightforward reason.
Unveiled at the company’s annual September showcase, the book-style foldable smartphone has a 5.4-inch exterior screen and opens to reveal a 7.6-inch display. It is not the most expensive smartphone on the market, but it is the most expensive iPhone Apple has ever released.
The 256-gigabyte entry model starts at $1,999, or €2,339. At the other end of the range, the two-terabyte version costs $3,199 or €3,839.
GlobalData believes Apple’s brand and vast installed base could accomplish what seven years of foldable smartphones have not: move the category from niche to mainstream.
For argument's sake, I'm willing to accept that Apple will make folding phones more desirable. But will they make them more useful?
What problem do foldable phones solve
In practical terms, a foldable phone tries to put a larger screen into a device that remains small enough to carry in a pocket. Book-style models become small tablets, while flip-style foldables make a conventional smartphone more compact.
The idea has older roots.
Clamshell phones became popular because they solved practical problems. They could fit a reasonably large keypad and screen into a small pocket. Closing the two rigid halves protected both.
The hinge also offered something the modern touchscreen later removed: a physical action with an unambiguous result.
Models from Motorola, Samsung, Nokia and LG turned that function into fashion. The slender Motorola Razr, launched in 2004, demonstrated that a hinge could become part of a phone’s identity rather than a mechanical necessity to be hidden.
Then came the glass rectangle.
Touchscreen smartphones replaced buttons with a single adaptable surface. Applications could put controls wherever they needed them, while videos, websites, maps and photographs benefited from uninterrupted displays. Hinges disappeared because they divided the device precisely where manufacturers wanted more screen.
Over time, however, the rectangle grew. Consumers wanted larger displays, but hands, pockets and handbags did not expand with them. The modern foldable promises to resolve that contradiction.
That is a genuine function. The uncertainty is how many people need it.
How does a foldable smartphone screen work?
An old flip phone folded the casing around a conventional rigid screen. A modern foldable bends the display itself.
This is vastly more difficult.
A flexible display consists of organic light-emitting diode pixels, touch-sensitive components, protective films, adhesives and extremely thin glass. As the phone closes, these layers must bend without cracking, separating or crushing the pixels.
They must also move fractionally against one another because the outside of the curve travels farther than the inside. Research into deformable displays identifies fractures, delamination, buckling and permanent deformation among the principal engineering risks.
The hinge controls how that stress is distributed. If the fold is too tight, the display suffers. If it is too loose, the phone becomes thick and the screen may not lie flat.
Apple says the iPhone Duo’s hinge contains more than 100 components. High-strength glass sits above and below the folding display panel, while custom adhesives allow its layers to glide past one another as the phone closes. A titanium plate provides additional support underneath.
The company has given the Duo an IP68 water- and dust-resistance rating. A nano-textured surface reduces reflections, while the display construction is designed to minimise stress and make the crease less visible. Apple calls the resulting screen smooth and flat, but its real-world appearance and durability will need to be assessed independently once the phone reaches buyers on 23 October.
This is impressive engineering. It is also an enormous amount of work to make a screen behave slightly more like a sheet of paper.
Why have foldable phones remained niche?
The first wave of folding smartphones showed how much could go wrong.
Chinese display maker Royole shipped the FlexPai in 2018, but Samsung brought the format to global attention with the original Galaxy Fold in 2019. Its launch was delayed after review devices developed display failures. In one case, material entered the device and affected the screen; some reviewers also removed an essential protective layer after mistaking it for a conventional screen protector.
Samsung retrieved the review devices, altered the design and released the phone later that year. The troubled debut did not kill the category. Huawei, Motorola, Google, Honor, Oppo and others subsequently developed their own foldables.
Two main formats emerged. Book-style phones open into small tablets, promising more room for work, reading and video. Flip-style smartphones fold into a smaller package, echoing the compact appeal of the old clamshell.
Creases have become less pronounced. Hinges have become slimmer. Water resistance has improved, applications adapt more smoothly and foldable phones no longer feel quite as much like public prototypes.
Even so, high prices, concerns about durability and uncertainty over the benefits of the larger display have kept them outside the mainstream. Apple is not stepping into a new category. It is entering one whose engineering has advanced more quickly than its consumer appeal.
A smartphone innovation people can see
The smartphone industry has a differentiation problem.
In mature markets, almost everyone likely to buy a smartphone already owns one. Even mid-range models are fast enough for everyday tasks and take good photographs. Premium devices continue to improve, but faster processors, brighter screens and better image processing rarely transform the basic experience.
Replacement cycles have lengthened partly because older phones still work perfectly well.
For manufacturers, a folding screen has one enormous advantage: its novelty is visible. A customer may struggle to recognise a modest processor improvement while standing in a shop. A phone that opens into a tablet demonstrates its difference in seconds.
That does not make foldables a confidence trick. Their displays, hinges and materials represent real advances. The larger screen can also be useful.
A traveller might keep a map open beside a booking. An employee could read a document while answering an email. A photographer might edit an image on a larger canvas. Apple allows two applications to run side by side on the Duo. Support for the USB-C Apple Pencil is due to arrive later in 2026, rather than at launch.
The practical test is whether people do these things frequently enough to accept a more mechanically complex and considerably more expensive device.
Technological difficulty and consumer value are not the same thing. Engineers can solve an exceptionally demanding problem without proving that most people needed it solved.
Function is not only about efficiency
There is another possibility. Perhaps the pleasure of using a foldable is itself part of its function.
My old LG was not valuable merely because it occupied less space. Opening and closing it gave each interaction a clear beginning and end. The movement made the phone easier to understand and more enjoyable to use.
Form can shape behaviour in less measurable ways. A satisfying physical action can create attachment to a product. A screen that stands partly open can become its own camera support, bedside display or miniature laptop. A phone that folds into a smaller package may simply feel nicer to carry.
The danger comes when the spectacle survives but the pleasure does not. A hinge that is delightful during a shop demonstration may become an inconvenience when opening the phone requires two hands, or a source of anxiety when grit appears near the display.
What compromises does the iPhone Duo make?
Despite its premium price, the iPhone Duo omits some features found on Apple’s conventional Pro models.
It has two rear cameras rather than the Pro models’ three-camera system with a dedicated telephoto camera. The Duo can produce an optical-quality 2x zoom using its main sensor, while the iPhone 18 Pro models offer up to 8x optical-quality zoom. Touch ID sits in the Duo’s side button instead of using Face ID.
These decisions may reflect the fierce competition for space inside a device containing two displays, a hinge and batteries divided between both halves. Apple has not, however, publicly attributed every omission to a lack of space.
The interior display also requires more care than the rigid outer glass of a conventional smartphone. Independent testing will show how well Apple’s durability claims survive everyday grit, drops and thousands of openings.
Price creates a more fundamental contradiction. The Duo may attract attention to foldables, encourage application developers and give suppliers confidence to expand production. A phone starting at $1,999 is nevertheless some distance from a mass-market device.
An installed base can give a new product an enormous potential audience. It cannot create an everyday need for it.
Will Apple make foldable phones mainstream?
IDC expects global smartphone shipments to fall by 16.7% in 2026 as sharply higher memory costs push up prices. Foldables are a rare exception: the research firm forecasts shipments will grow by 12.6% to 22.9 million devices, largely because of Apple’s arrival.
That would still leave foldables representing only a small fraction of the billion-plus smartphones expected to ship this year.
Apple has repeatedly demonstrated that changing the form of a device can encourage new behaviour. A larger display invites more reading, a better camera produces more photographs and a watch on the wrist creates new reasons to monitor health.
The iPhone Duo may similarly inspire applications and habits that are difficult to predict before millions of people own one. Apple’s scale could persuade developers to design seriously for folding screens, while larger production volumes may eventually reduce component costs across the industry.
But that future is not guaranteed. The larger display must become useful often enough to outweigh the price and additional mechanical risk. Otherwise, the fold will remain a magnificent demonstration feature: delightful in a shop, less essential after two years in a pocket.
My old LG folded because the hinge made the phone simpler to carry, protect and use. That made sense.
The iPhone Duo is undoubtedly a remarkable technical achievement. Given its price, I am not entirely convinced that it makes quite as much sense.
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