A smartphone with two screens - one of which uses e-ink technology and is "always on" - has been launched.

The Russian company Yota said the phone would go on sale online immediately in Russia, Austria, France, Spain and Germany.

The Android-powered phone promises to
extend battery life by transferring web pages and other applications to the e-ink screen.

Experts said it may prove attractive to users fed up with drained batteries.

The phone has one LCD display, similar to those found on other smartphones, and a second e-ink screen which the company says lets users see the information they want without having to wake up the phone.

"The typical user picks up and activates their smartphone more than 150 times a day," said Yota Devices chief executive Vlad Martynov.

"Why? Because users worry that messages or information they need or want are hidden behind their phone's black screen. This is a huge distraction and can impede meaningful interaction with our friends, families and colleagues."

St Petersburg-based Yota is best known for making modems and router equipment. The dual-screen smartphone, which was first announced in 2012, is the company's first mobile phone.

"The YotaPhone is an ambitious concept and although it will be considered a gimmick by many we believe there is merit in the design," said Ben Wood, a mobile analyst with research firm CCS Insight.

"With many smartphone owners struggling to make the battery on their device last a whole day, the option to have a secondary screen that uses little or no power to capture and display a 'snapshot' of the main screen could be attractive," he added.

Yota plans to launch the phone in 20 other countries by March 2014.

It also features a 1.5GHz dual-core processor and a 12-megapixel rear camera and will cost 499 euros.

Mr Wood said that the YotaPhone has some "smart ideas" about how the secondary e-ink screen could be used.

"Some are just nice touches along the lines of displaying a love heart when a text message arrives with the words, 'I love you'. Others are more intriguing, such as using the e-ink display for advertising. This could open up some interesting new business models in future," he said.

E-readers could be slimmer in future after a thinner screen was developed by the company E Ink.

The new screen technology, known as Fina, is up to 50 percent lighter and thinner than current screens according to the company.