Samsung Electronics Co. showed off a new phone with a foldable screen in a bid to shake up a smartphone business awash with black, shiny rectangles that look increasingly similar.

At its conference Wednesday for software developers in San Francisco, the company previewed what it called an Infinity Flex Display and announced new software for controlling the large phone. Developers will be able to create apps for the gadget, which like other Samsung phones will be based on the Android operating system.

The South Korean technology giant didn't say when the device will go on sale, how much it will cost or what the phone will be called. During the presentation, Samsung also disguised the rest of the phone's design by covering everything beyond the screen with extra casing — similar to how prototype cars are camouflaged during street testing.