The optical device 11, wherein {HEAD ~ the surface area} of {TAIL ~ the used part} is no more than one third of the total surface area of the spatial light modulating element 
of
The optical device 11 , wherein { HEAD ~ the surface area } of { TAIL ~ the used part } is no more than one third of the total surface area of the spatial light modulating element
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH