I don't know for sure how to determine the XY resolution, but here are two things to consider.

1) The resin states it's 405nm, so is 405nm the minimum "voxel" size in any dimension? So that would be 0.000405mm. That doesn't mean the printer couldn't handle a finer resolution, but the resin will limit you.

2) The LCD screen will have pixels, so if we assume it is a 1080p screen, then we have a resolution of 1920x1080. Our XY area is 180x69mm, so the projected pixel sizes would be x = 180/1920 = 0.09375mm, y = 69/1080 = 0.06389mm

So 0.094mm and 0.064mm seem like more believable resolutions to me, but again, truthfully I don't know how to determine the correctly resolution. I'd like to know the resolution of the LCD screen.