Backlight On Sliding Keyboard

[babyjordin23]

I know this probably 1 of the easiest questions on this site lol..but i'm havin a hard time trying to make the light longer on the sliding keyboard...it seems like it goes out to fast and i have to guess the buttons when writing a txt in the dark and i hate that, i'm not sure whats the longest the light can stay on but can sumbody help me figure out how to chg the backlight to a longer time...thanks!