IT SOUNDS like a dream come true: a smartphone that only needs recharging every few weeks.

While most phone makers are leap frogging each other with smartphone screens that are bigger, brighter and bolder, one of the phones to make headlines at the Mobile World Congress last week was a prototype of a smartphone with a black and white screen and a battery that would leave its colourful counterparts for dead.

E Ink, the maker of electronic paper displays, had two prototypes of phones running on the Android operating system.

The prototype phones were loaded with a web browser, a message inbox, a contact directory and an ebook reader.

Because an E Ink device only uses battery power when it’s redrawing the screen, the battery life on the prototypes was said to last up to a month or several weeks of normal use.

The E Ink phone uses the same screen technology as Amazon uses in it’s Kindles and Pebble uses in it’s eWatch.

Demonstration of the prototypes showed that the screen was slow to refresh the web browser but the pay off for the need for patience was the screen was viewable in bright sunlight at any angle.

Nicholas Carbonnier, of ARMdevices.net, told the blog Laptop that the prototypes could be made as a low-cost option for under $200 that would suit people in markets where limited power supply was a greater concern than full smartphone features.

Carbonnier said E Ink was also working on clip-on covers for popular smartphones, that would add an E Ink screen to the back of the phone.

Russian manufacturer Yota also showed off its dual-screen smartphone, which had a normal colour screen on one side and a black and white E Ink screen on the other.

Yota said the dual-screen phone would have a much longer battery life, because people would read long articles, check social media updates, display photos and boarding passes without having to drain their phone’s battery or wake it up from sleep mode.

The E Ink screen on the Yota phone even displays an image when the phone battery is dead.

The Yota phone, which was unveiled at International CES in January, will be produced by a Singapore company and launched late this year.