What is this strange part in K770i ?

hello,
anyone know what is this part in K770i phone? Please help,
http://img195.imageshack.us/img195/1757/phonepart.jpg

it is the ligth sensor, most of the new phones have this, like in nokia n72/n70, w300 and so on

Blinks when your battery is about to die. I mean 60 secs or less....