Microsoft's new phones will use an iris scanner to let you unlock your phone with your face

Microsoft is hosting an event tomorrow that will see the introduction of two new Lumia devices, the first flagship phones since the company acquired Nokia in 2014. The new phones, dubbed the 950 and 950XL, will have big screens, fast processors, and the ability to unlock the handset with just your face.

Windows Hello, a feature introduced in Windows 10, makes this possible by using an iris scanner to check the identity of the user logging into the PC or phone. Intel has developed a camera, called RealSense, that is capable of working with Hello on a PC and it would seem Microsoft has done a similar thing with the Lumia handsets.

A leaked photo of the Lumia 950XL, from the Twitter account @Windows10Lover, shows an iris camera that would allow Windows Hello to unlock the phone. The software requires a high-resolution camera in order to verify the user accurately. Intel's RealSense has a 3D lens, an infrared lens, and a regular lens. Microsoft's version likely follows a similar design.

By adding facial recognition, Microsoft gives a compelling reason to buy a Windows phone. Neither Apple, Google or Samsung have moved beyond finger print recognition and Hello is as good in practice as the company makes out.

The event starts at 10am EDT (3pm BST) and will also see the introduction of the a new Surface Pro 4 as well as updated Microsoft Band.