Hi, time to join the black screen party!
Can I give some advise. Remove your phone from any case and remove any screen protector. Look at the level of the glass screen around the perimeter of the frame. If like mine you will notice in the upper right hand corner (above the word Nokia) you may see
the glass is slightly lifted compared to the top left hand side!!..perhaps 0.5mm to 1mm!!
Either way this is enough for the problem to occur and I have verified it but putting my phone in a case that rests on the edge of the glass and hold it down (no black screen problem now!!).
My phone is approximately 6 months old.
I beleive this is a manfacturing defect with the adhesive tape used to bond the curved glass screen to this the chassis.
I will be sending mine in for repair but at present I can't be without it until I get a temp phone.
It's funny to realize that it work out (right here), but for a little while. If it's just this, okay ... but it's crazy.