Wow, thanks for that. An infrared laser, I stand corrected. >To detect whether there is something in front of the iPhone X, it is believed that the phone uses

Wow, thanks for that. An infrared laser, I stand corrected. >To detect whether there is something in front of the iPhone X, it is believed that the phone uses a "time-of-flight" (TOF) sensor, powered by an LED-based infrared illuminator... If the TOF sensor detects an object, it triggers the iPhone X's True Depth camera to take a picture. If that reveals a face, the phone activates its dot projector, shining a single infrared VCSEL through an optical system to create 30,000 spots while its infrared camera captures an image. It sends both regular and spottily illuminated IR face images to an application-processing unit (APU) that can recognize the owner and therefore unlock the phone.