In a dual focusing optical pickup device, {HEAD ~ a laser beam} is incident on an optical member via {TAIL ~ a beam splitter} 
is incident via
In a dual focusing optical pickup device , { HEAD ~ a laser beam } is incident on an optical member via { TAIL ~ a beam splitter }
OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL OTH OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL