{HEAD ~ The beam} which is reflected by the optical member and the beam which is reflected by the reflecting member after being transmitted through the optical member generate {TAIL ~ a dual focus} on the optical disc, in which the dual focus has different focal distances 
generate
{ HEAD ~ The beam } which is reflected by the optical member and the beam which is reflected by the reflecting member after being transmitted through the optical member generate { TAIL ~ a dual focus } on the optical disc , in which the dual focus has different focal distances
HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH