Display black but phone/touchscreen works

Hello,

I got a Z3 one year ago.

But spontaneously the screen just stayed black.

I can boot the phone, the backlight is working. I wait a little bit but the screen is still black.

BUT I can touch and select camera and take a photo. I know, because I can hear the sound of camera. I can open the dial pad and dial a number, I can hear the different sounds.

The phone is original, have never been opened, no other software.

I already tried with "Xperia Companion" to install latest updates and repair the phone. Nothing worked.