I'm talking about the fact that proximity sensor is always working, even if it does not using by the phone.
I experimented with IR camera, and found that all lasers (IR camera flash laser, dot projector laser, and proximity sensor laser) are working continuously. IR camera making shots one time per 2-3 seconds, dot projector also one time per several seconds, and proximity sensor laser activity has frequency about 2-5 cycles per second.
When I disabled checking of user attention to prevent locking of the device (in FaceID settings), I saw that IR camera stopped to work periodically. When I disabled measuring of the distance to face for eyes safety, then dot projector also stopped periodical work. Now both IR flash and dot projector working only when FaceID is trying to detect face.
However, proximity sensor laser starting to flash when screen is turned on and phone is unlocked. It works continuously, most time without of purpose and just drains the battery.
In any case - all 3 parts are LASERs. It's bad idea to flash by any lasers to human eyes continuously. Even they are IR and invisible to eye. This emission is absorbed by the retina of the eye anyway.
All my previous phones activated proximity sensor only during the call, and this is right behavior.
