The launch of Microsoft's latest flagship phone, the Lumia 950, has been delayed due to issues with a biometric authentication device that it features, according to trade media.The target date for the only carrier-release version of the Lumia 950 in the US is now November 20, wrote Windows Central on Friday, adding that “part of the launch delay we are told was to enable Windows Hello's iris scanner”.Speculation has surrounded the feature since the phone's launch, with experts raising doubts to Planet Biometrics that this was truly iris authentication and not infrared facial recognition or eye recognition.A Microsoft spokesperson told Planet Biometrics “Windows Hello Beta for Lumia uses the infra-red authentication camera, focusing on your eye and iris to unlock the device in an incredibly personal way.”In terms of iris authentication rather than face recognition, this is a new complementary technology to face and fingerprint recognition. It is also well suited to the personal way you use a phone, looking closely at the screen.”In Windows 10 on laptops, Hello uses a special RealSense depth camera module designed by Intel.Other manufacturers are working on iris scanners for smartphones, with California-based biometric authentication firm Delta ID revealing in May that its ActiveIRIS technology powers the iris recognition system of the ARROWS NX F-04G smartphone launched by the Japanese telecoms carrier NTT DOCOMO in cooperation with Fujitsu.