Free idea for the creators of low price tablets for education

Reading is as important in this century as in the previous one. Since reading will begin to take place on tablets I suggest the following idea.
The idea is to make tablets or smartphones easy and comfortable to read on. Since LEDs are small why not have two types. One ordinary backlight for perfect colors and one additional ”warm” backlight adapted for reading. With warm backlight I mean backlight similar to warm LED bulbs. Then using an optional switch in android for the tablet people wont strain their eyes trying to read a school textbook.