Therefore, the process to construct {HEAD ~ the optical pickup device} is easy, and thus, the errors generation ratio of {TAIL ~ the optical pickup devices} is sharply decreased 
Therefore , the process to construct { HEAD ~ the optical pickup device } is easy , and thus , the errors generation ratio of { TAIL ~ the optical pickup devices } is sharply decreased
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH