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