Display materials

Foldable smartphones typically use flexible, plastic OLED displays rather than glass (such as Corning's Gorilla Glass product, which is used in the majority of mid and high-end smartphones). Plastic displays are naturally capable of sustaining the required bend radius for a foldable smartphone, but they are more susceptible to blemishes and scratches than traditional glass smartphone displays. Although Corning does produce a flexible glass product known as Willow Glass, the company states that its manufacturing process requires use of a salt solution—thus making it unsuitable for electronic displays because the salt can damage the transistors used in OLED panels (which are built directly on the panel). Nonetheless, the company stated in March 2019 that it was in the process of developing a flexible glass suitable for smartphones, which would be 1 mm (0.039 in) thick and have a 5 mm (0.20 in) bend radius.^[14]

Samsung marketed its Galaxy Z Flip as featuring 30 μm (0.0012 in)-thick "ultra-thin glass" with a plastic layer similar to the Galaxy Fold, manufactured by Samsung with materials from Schott AG, which is "produced using an intensifying process to enhance its flexibility and durability", and injected with a "special material up to an undisclosed depth to achieve a consistent hardness". A stress test by YouTube channel JerryRigEverything showed the screen was scratched when rubbed with a pick with a Mohs rating of 2 (in comparison, most smartphones tested by the channel begin to experience scratches with 6 and 7-rated picks), placing its durability in line with other folding phones. However, The Verge did note Samsung's statement that the device contained a protective polymer layer similar to that of the Galaxy Fold.^[7][15]

Predecessors

In 2006, Polymer Vision showed a roll-able concept and a foldable smartphone, the Readius (zh), at the Mobile World Congress (MWC) which also serves as a reader.^[16][17][18]

In 2008, Nokia presented animated concepts of a flexible device it dubbed "Morph", which had a tri-fold design that could be bended into various forms, such as a large unfolded device, a feature phone-sized unit, and a smart wristband.^[19] In a 2019 retrospective on the concept, CNET noted that Morph could be considered a forerunner to the first wave of commercially produced folding phones, as well as a showcase of future possibilities.^[20]

In 2011, Kyocera released a dual-touchscreen Android smartphone known as the Echo, which featured a pair of 3.5-inch touchscreens. When folded, the top screen continued to face the user while covering the secondary screen. Two individual apps could be shown on the displays, a single app could span across them, while specific apps also featured "optimized" two-pane layouts.^[21][22] Two years later, NEC released the Medias W in Japan. Unlike the Echo, the secondary screen could be folded behind the phone. The camera rotated with the screen so that the same sensor could face both forward and rear^[23] In 2017, ZTE released the Axon M with a similar hinge to the Medias W. ZTE stated that the more powerful hardware of modern smartphones, and improvements to multitasking and tablet support on Android, helped to improve this experience.^[24]

The development of thin, flexible OLED displays enabled the possibility for new designs and form factors. During its Consumer Electronics Show keynote in 2013,^[25] Samsung presented several concepts—codenamed Youm - for smartphones incorporating flexible displays. One such concept was a smartphone that could fold outward into a single, uninterrupted tablet-sized display. The first Youm concept to make it to a production model was the Galaxy Note Edge—a phablet with a portion of the screen that sloped over the right-hand bezel.^{[26][27][28][29]}

Emergence

Speculation surrounding the development of folding phones using OLED displays began to emerge more rapidly in 2018. In January 2018, it was reported that LG Electronics had obtained a design patent for a folding smartphone.^[30] Later in June, it was reported that Microsoft had been developing a similar device as part of its Surface line, codenamed "Andromeda" (itself a spiritual successor to a dual-screen booklet tablet prototype Microsoft had been exploring in the late-2000s known as Courier),^[31][32] while Samsung was also said to be developing such a device.^[33] Other companies expressed interest in the concept, or have received patents on designs (such as hinge implementations and overall designs) relating to foldable phones. Motorola Mobility had received patents for a horizontal folding smartphone reminiscent of clamshell feature phones.^[34][35][36]

In November 2018, the Chinese startup Royole released the first commercially available foldable smartphone with an OLED display, the Royole Flexpai. It featured a single 7.8-inch display that folds outwards, leaving the display exposed when folded.^[37] Later that month at its developers' conference, Samsung officially teased a prototype of its folding smartphone, which would be produced "in the coming months". The prototype used a booklet-style layout, with an "InfinityFlex" display located on the inside of the device, and a smaller "cover" screen on the front of the device to allow access when the screen is closed.^[38] At a concurrent developers' summit, Android VP of engineering Dave Burke stated that the next version of the platform would provide enhancements and guidance relevant to folding devices, leveraging existing features.^[39]

In January 2019, Xiaomi CEO Lin Bin published a video on Sina Weibo, featuring him demonstrating a prototype smartphone with two flaps capable of being folded inward.^[40] Samsung officially unveiled the Galaxy Fold during its media event at Mobile World Congress in February 2019.^[41] Alongside the Galaxy Fold, the convention also saw other foldable phones being unveiled or teased, such as the Huawei Mate X,^[42] and TCL presenting various prototype concepts featuring its "DragonHinge" technology (including a bracelet-styled device).^[43]

In April 2019, the impending launch of the Galaxy Fold was met with quality concerns from critics, after widespread reports of review units experiencing varying forms of display failure (in some instances caused by accidental removal of a plastic layer meant to protect the screen in lieu of glass, along with other failures). Samsung indefinitely postponed the device's release, stating that it needed time to investigate the failures and improve the device's durability.^[8][44] Huawei also delayed its Huawei Mate X, with the company citing its desire to take a "cautious" approach due to the Samsung Galaxy Fold.^[45][46] These led to public scepticism regarding the durability of these cutting-edge foldable devices, especially with their high price points.^[47][48][49] Samsung's Galaxy Fold was eventually released in September 2019 as the first mass-market foldable smartphone, followed shortly thereafter by Huawei's Mate X in China only.^[49]

In November 2019, Motorola Mobility unveiled its Razr clamshell—inspired by its former Razr feature phone line released on 6 February 2020.^[50][51] Samsung also announced a similar device known as the Galaxy Z Flip.^[52] These used the foldable display technology in a different vertical-moving layout and thus effectively a modern take of the characteristic 2000s flip phone.^[53]

Further developments

In spite of durability concerns at the beginning, foldable smartphones have been claimed to have improved to be less suspectable to breaking thanks to improved hinges and other components.^[10] In many book-style examples, wedge gaps have been reduced or eliminated partly by "waterdrop" hinges.^[54] The adoption of thin glass displays after 2020 also helped durability by not falling for dust particles going inside the display. In clamshell foldables, external cover screens have expanded from tiny notification strips to larger displays which on some models are usable for certain apps and tasks without having to unfold the device.^[55]

In September 2024, the Huawei Mate XT was introduced as the first double-folding, or tri-fold smartphone.^{[56][57][58][59][60]} The device can be used with a case that has a kickstand, and a foldable keyboard with a built in trackpad to provide a desktop PC-like experience.^{[61][62][63][64]} On 1 December 2025, Samsung announced their Samsung Galaxy Z TriFold, a tri-folding smartphone.^[65][66] Both are part of an entirely new category of foldables that expand the book-style form further to make full-sized tablet screen sizes possible.

Userbase

User analysis suggest that book-style foldables are popular among productivity workers and partly driven by multitasking and documents. Clamshell-style foldables find higher popularity among younger people with emphasis on fashion and compactness.^[68] Tri-fold foldables are expected to target a luxury market with both mobile workstation and widescreen gaming and cinematic entertainment usage.^[75]

Full list of vendors

The following vendors have commercially released and marketed at least one foldable smartphone: