Samsung today finally showed off its foldable phone: a device that can convert from a handset to a mini tablet through the use of two displays.

The device uses what Samsung calls an Infinity Flex Display and functions like a book. When closed, it resembles a compact smartphone. But open it up for a 7.3-inch flexible display, which Samsung says will support three active apps at once.

Samsung did not announce a launch date or pricing, saying only that the Infinity Flex Display will begin mass production in the coming months.

"We've been living in a world where the size of your screen can only be as large as the device itself," Samsung VP Justin Denison said at the company's developer conference in San Francisco. "Well, we've just added a new dimension."

The company unveiled the device at the event in a bid to entice third-party companies to begin designing apps for the radical new product.

During the conference, Samsung also previewed other upcoming screen technology that can cover most of the device, and eliminate the intrusive notch for a smaller cutout.

The Korean vendor isn't the only company working on a foldable phone. Huawei is working on one, too. And last week, a little-known startup called Royole also introduced the Flexpai, which it plans on selling in China next month. We had a chance to try it, but weren't totally sold. Time will tell if Samsung can offer a better take on the technology and convince consumers to buy it.

"Samsung needs to focus on perfecting a few killer use cases when a product does come out," said industry analyst Patrick Moorhead in a tweet. "Spray and pray won't work here."