Raptor 27 become bright

Hi, it happens since now 3 times, basically from day to day i turn on my pc and my screen become more bright, but the bright on the screen still on 100, happens 3 times, i tried update video card, razer driver, windows, everythings but seems not changing, then after some days screen go back to normal bright, today after 3 month still went back to be more bright and i dont know what i should do.