What is this infrared light on my iPhone 4 and how do I turn it off? This is a picture of my iPhone 4 that I just took with an infrared-capable camera.
As you can see, there is a light on top, around the middle. You can only see it with with an infrared-enabled camera, and it usually blinks whenever the screen is lit up and turns off when the screen gets turned off.



I find it super creepy, and would LOVE to turn this thing off. Whether I'm in my right mind to freak out about something that is a) concealed (not visible by human eyes) and b) whose purpose is super shady is really mostly my problem, but I'd love to know if it can be done.
Besides from the freaky part, I used to be able to use my iPhone 3gs all day long with the same charge and the battery on this sort of newer iPhone 4 has a much lower duration, maybe because this little light-thing blinks so much all the time?

The information I've found online mentioned Siri being the cause of this, so I turned off Siri. Before I took the picture.
Well, that is the proximity sensor which should detect when you hold the phone to your ear and turn off the touch screen, etc. On my iPhone 5 it is only active when I make a phone call or use a App that uses it (e.g. SmartSleep). It is also visible to the eye when you are in a dark room.

These (rather old) articles (1, 2) has more info and states that this is a known problem on the iPhone 4. They suggests to try the following:


Hard reboot (hold power and home button until the Apple logo appears again)
Reset your settings (Settings > General > Reset > All Settings)
Reset Network setting (Settings > General > Reset > Reset Network Settings)


After resetting you should also reboot the device.