Lenovo ideapad y700 15inch display problem

Lenovo ideapad y700 15inch display problem

my Lenovo ideapad Y700 15inch display isn't working. What happened just the battery was low and didn't realize until the laptop turned off I plugged it turned on but no display showed not even backlight! I connected it to an external screen it's perfectly running tried everything its not working! Any help is appreciated thank you!