Sony has unveiled the world's first smartphone to have a 4K definition high-dynamic range (HDR) screen.

The two technologies are common in large screen premium televisions, but this is the first time the ultra-high definition and colour contrast has been placed into a 5.5-inch smartphone screen, Sony's new Xperia XZ Premium.

It means users will be able to download and watch movies and TV in 4K directly on their smartphone.

Sony's Hideyuki Furumi said of the announcement: "We've continued to evolve and transform our smartphone portfolio, with an unwavering focus on delivering the most advanced technology in elegantly designed products.

"Whether it's a memory-stacked camera system capable of super slow motion capture or the world's first 4K HDR smartphone display, we're delivering experiences that connect with users in emotional and meaningful ways like never before."

The device also has an improved camera which is capable of shooting slow motion video at 960 frames per second (fps), four time slower than any other smartphone Sony says.

The XZ Premium was the lead among a flurry of new devices announced by the Japanese technology giant during their press conference ahead of the opening of Mobile World Congress (MWC) on Monday.

Sony also unveiled a compact version of the Premium called the XZs, which also has the slow motion camera capabilities, while both phones are also water resistant.

There were also two further mid-range smartphones announced, the Xperia XA1 and larger screen XA1 Ultra, both of which come with 23 megapixel rear cameras and high-end 16 megapixel selfie cameras.

Away from smartphones, Sony revealed its concept interactive projector, Xperia Touch, which can turn any flat horizontal or vertical surface into a touchscreen will go on-sale this spring.

The device, which can connect with Android smartphones and tablets turns the device's screen into a 23-inch HD touchscreen for playing games and using apps or watching movies streaming from a user's phone.

There was also an update to Sony's concept wearable, Xperia Ear, an earpiece from which users can control using head movements to listen to music, exercise and send messages to friends.

The new "open-style concept" enables users to listen to music and have messages read into their ear while still hearing sounds from the world around them.