Place the small screen on the optical bench facing the mirror at a position that can capture the light reflected by the mirror without interfering with the light coming from the object to the mirror.
(the light; coming; from the object; to the mirror) (the optical bench; facing; the mirror; L:at a position) (a position; can capture; the light reflected by the mirror) (the light; reflected; by the mirror)
the light the optical bench a position the light
coming facing can capture reflected
from the object to the mirror
the mirror L:at a position
the light reflected by the mirror
by the mirror