Which part of some LED TV screens acts as two gratings crossed at non-straight angle?
The hexagonal array pattern of AMLCD fine pitch pixels lends itself to the 30,60 deg aliasing patterns found in your photography in LG 4k/5k monitors.  The pixel emissions may be orthogonal, but here we are looking at highly reflective vectors under a non-reflective coated glass.

Technically it is best called a Fraunhofer diffraction pattern.

In 35mm SLR photography,  the aperture shape can cause this with edge diffraction.  In software, it is called the Starburst or North Star Effect filter. 
 
https://en.wikipedia.org/wiki/OLED