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