Even when the optical disk has a defect, {HEAD ~ the laser beam} is continuously irradiated onto {TAIL ~ the optical disk} 
is continuously irradiated onto
Even when the optical disk has a defect , { HEAD ~ the laser beam } is continuously irradiated onto { TAIL ~ the optical disk }
OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL