whene i adjust the brightness from 100 to eny value the Left side of laptop screen cam darker than the right side

i patch my dtsdt to get brightness slider working by addiding this code in the dtsdt

Device (PNLF)

{

Name (_HID, EisaId ("APP0002"))

Name (_CID, "backlight")

Name (_UID, 0x0A)

Name (_STA, 0x0B)

}

brightness working fine but the left side in to darker from the right side

is there eny solution and thanks