Samsung has unveiled a folding handset at an event in San Francisco.
It described its Infinity Flex Display as “the foundation of the smartphone of tomorrow” and said it intended to start production within months.
When unfolded the device resembles a 7.3in (18.5cm) tablet. When closed a separate smaller display on the handset’s other side comes into use.
Samsung has teased the concept for more than five years and had been vying with Huawei to show off a device first.
However, both were upstaged a week ago when a little-known start-up, Royole, unveiled a foldable phone of its own.
Unlike Royole’s FlexPai, Samsung obscured the final look of its device by placing it in a case so as to hold off revealing its look until a later event.
Neither did it disclose how it will brand the phone.
It did, however, reveal that the forthcoming handset would be able to run three apps at once.
Shipments of Samsung’s smartphones were 13.4% lower in the July-to-September quarter than for the same period the previous year, according tomarket research firm IDC.
Although the sector as a whole shrank over the 12 months, the South Korean firm still underperformed, with its market share slipping from 22.1% to 20.3%.
But analysts say a flexible phone has the potential to strengthen Samsung’s brand and boost interest in its wider family of devices.
“We’ve already had squeezable, swivel, clamshell and even foldable phones,” commented IDC’s Marta Pinto.
“Differentiation is super important. Samsung’s smartphone sales are declining as it faces serious competition from Huawei and other Chinese brands.
“If it can bring a new and really interesting device to the market it could be a chance to regain momentum and return to growth.”
Google is also holding a developer event of its own for Android programmers.
One of its engineering chiefs announced that it would soon add support to the operating system to allow other manufactures to create foldable phones of their own.
It also tweeted an animation of the concept in action.
IBM Simon: The first mobile phone to offer a touchscreen user-interface – but its battery only lasted an hour.
Siemens S10: The first handset with a colour display – although only red, green, blue and white could be shown.
LG Prada: The handset debuted a capacitive touchscreen – detecting finger taps by changes in the display’s electrical field rather than pressure.
iPhone: Apple made use of “multi-touch”, detecting several points of contact – allowing pinch-to-zoom and other interactions.
Nokia N85: First phone with an OLED (organic light-emitting diode) display, letting it show deeper blacks and better contrast.
Samsung Galaxy Note: Although not the first “phablet”, the handset proved there was demand for a 5+ inch display, despite claims it was “comically huge”.
LG G Flex: The curved design was derided as being a gimmick, but points the way to the true “bendy” phones of the future.
Sharp Aquos Crystal: The phone’s “edgeless” look foreshadowed today’s trend to keep bezels to a minimum.
Samsung Galaxy Note Edge: Samsung’s first handset to wrap its screen over one its sides used the extra space for notifications and app shortcuts.
Sony Xperia Z5 Premium: The smartphone premiered a 4K display before it was easy to obtain such ultra-high definition mobile content.
Essential Phone: The start-up beat Apple to featuring a camera notch in its display, which allowed the rest of the screen to extend upwards.
Royole FlexPai: The California-based start-up surprised the industry when it revealed the “world’s first foldable phone” last month.