The Flex Display Phone and the screen in three sizes

What it was

The Flex Display Phone began as a sales tool. In November 2008, Taiwan’s Industrial Technology Research Institute (ITRI) revealed a flexible 5-inch screen and wanted handset makers to build products around it. It hired the design firm Pilotfish to draw a phone that showed what the screen could do. Hank Chen, an industrial designer at Pilotfish in Taipei at the time, posted the project to his Coroflot portfolio in July 2010. That is the version design blogs picked up.

The body was a block of hardware with the screen folded around it. Closed, it worked as an ordinary phone. With the front lifted like a book turned on its side, the half underneath lit up as a keyboard. Pulled out fully, the screen reached five inches for maps, video and the web. Chen summed it up as three sizes, three modes and three functions.

It took sixteen years and two hinges for a phone with three screen sizes to reach a store.

Where the idea went

ITRI’s screen was real, but the phone was a mock-up, and the schedule did not hold. In 2008 the institute said the technology would be ready the following year. In October 2010, when ITRI introduced a newer 6-inch flexible AMOLED called FlexUPD, Engadget pointed out that the 2009 smartphone promise had come and gone. We could not find a handset maker that built the design.

Screens that change size reached stores a decade after the mock-up, and they fold. Royole announced the FlexPai, a 7.8-inch tablet that folds down to a phone, in late 2018. Samsung’s Galaxy Fold followed in 2019 with a 7.3-inch display that opens like a book. The sliding half of the mechanism is still a demo. Samsung Display showed a prototype panel that both folds and slides at CES 2023.

The three-size idea itself arrived in September 2024. Huawei’s Mate XT folds twice and works at 6.4, 7.9 and 10.2 inches. Samsung’s own twice-folding phone, the Galaxy Z TriFold, was announced in December 2025 and confirmed as discontinued in March 2026.

What it means now

The scale has moved. In 2008, doubling a phone screen meant reaching five inches. The cover screen of a Galaxy Z Fold7 is larger than that before it opens, and the Mate XT unfolds to about twice the mock-up’s diagonal.

The wish has not moved. People still want one device that is a phone on the street and something bigger at a desk. The mock-up’s middle position, a screen above and controls below, lives on in half-open folding phones, where Samsung calls the split view Flex mode. The industry kept the fold and dropped the slide. We could not find a phone on sale whose screen pulls out of the body.