Why does my S5 screen flicker when I set brightness to least brightest?

[AC Question]

basically when I set my phone to least brightness or very low brightness, the bottom half of my S5's screen starts flickering.The top half is fine but the bottom flickers and sometimes the screen flickers green .I mean I can still read the screen but it bothers me so much ugh.Help please? I just got this S5 less than a year ago and ive tried turning off/restarting my phone, taking out the memory card and whatever.Doesnt work :/