Display not turning up after going to sleep

Strange, my phone is working fine when, switched on. However, ones it goes to sleep it wont turn up, mobile is on and ringing when called.

Again i need to remove battery and put back and swtich on , it works untill again it goes to sleep.

Tried using keep screen on but not working. Works as long as we keep using, ones go into sleep it wont turn up again and reboot is only option. Please help