Inverter bord or a LCD's screen? Darklight?

Hi,

I have a problem. I bought recently a new battery from Ifixit. The installation going well and the computer work fine for about 2-3 days of uses after the installation. Then, yesterday I open my computer and everything was fine at first and the luminosity fell down.

I restart the computer many time but nothing working. But, I was able to see my Dock space in background with a flashlight. I made a research but all the answer I fought was the inverter board or the LCD's screen remplacement. But I don't know with piece I should replace...

Can you help me, please? Thanks you!