a package containing the array of light emitting elements and the substrate, the package enclosed with a window, wherein {HEAD ~ the window} has {TAIL ~ two surfaces} 
a package containing the array of light emitting elements and the substrate , the package enclosed with a window , wherein { HEAD ~ the window } has { TAIL ~ two surfaces }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL