The smartphone is changing. From the pocket-sized devices of yore, our phones have grown into surrogate laptops for work on the go, and pseudo televisions for watching Netflix on planes. Samsung, the company that pioneered the "phablet," thinks it's time for something new. Something even bigger. Specifically, a phone that unfolds like a book to reveal a second, larger screen inside.

Samsung showed off its future-phone concept under dimmed lights at its annual developer conference today in San Francisco. The phone unfurls to offer a 7.3-inch flexible display for reading, watching television, or multi-tasking with multiple apps.

Samsung SVP of mobile product marketing Justin Denison shows off the folding phone prototype in the open position. The lights were purposely kept dimmed to highlight the screen, and to obscure the details of the hardware design. Eric Risberg/AP

"When it's open, it's a tablet offering a big-screen experience," said Justin Denison, Samsung's SVP of mobile product marketing. "When closed, it's a phone that fits neatly inside your pocket."

For now, it's still just a concept. Samsung declined to share a name for the product or a timeline for its release, and Denison quickly tucked the device back into his pocket after giving attendees a 20-second glance. But unlike Samsung's earlier attempts to make a bendable phone, this one seems to have staying power. Google announced today that Android will officially support bending screen designs, promising to create a "seamless" mobile experience for this and future devices that fall into the new category of "foldables."

For years, Samsung has pushed display technology to the edge, curving displays, shrinking bezels, and squishing pixels. Also, it proved people would buy a phone too large to hold with one hand, and changed the course of smartphone design for years to come. Maybe it can do that again with a bendy phone.

Flex Zone

Samsung has been trying to pull off a flexible phone since at least 2011, when it first showed off a dual-screen handset with a creaseless display. (Shoutout to this great piece of marketing from a few years later.) The pitch, both then and now, was a phone with more real estate to do the things a modern phone should do: watch television, chat with video, multitask between several apps. Two screens instead of one makes your phone even more of a pocketable computer.

The dream has been around for years, though it hasn't caught up to reality. Other companies, like Lenovo, Huawei, and LG, have each tried their hand at creating a foldable smartphone; just last month, electronics start-up Royole debuted its own take, called the FlexPai. But none of those prototypes have stuck, in part because designing a dual-screen phone comes with plenty of compromises. Double the screen means double the strain on your battery, and few apps are optimized to make use of all that screen space. Samsung's earlier designs, closer to the size of a Kindle than an iPhone, never even made it to market.

But Denison and other Samsung executives say display technology has improved to the point where it's now possible to fuse an ultra-thin screen onto the foldable design. Also, an update to Galaxy’s UI will help make the most of all that new screen real-estate. Samsung says users can run up to three apps simultaneously with a feature called "multi-active window."

Less clear are the details about how a foldable phone like this one will stack up to rigid-phone competitors, including Samsung's existing line of Galaxy phones. Plus, it's not clear that the demand is there for a dual-screen mobile. Chinese phone-maker ZTE recently tried it with the Axon M, which you likely forgot all about until right now. The key to cracking the dual-screen future won’t just be mastering the engineering or design, but convincing consumers they need such a thing in their lives.

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