OPTICAL DISK PLAYBACK DEVICE WITH PRESCAN FUNCTIONALITY FOR EARLY DETECTION OF SURFACE IMPERFECTIONS

摘要

optical disk reproducing device includes a first and a second laser and an optical assembly , and first and second optical detector , and a controller circuit coupled to the optical detector . An optical assembly , each of the first and the second being configured to direct incident light from the laser , the optical detector from the leading and trailing spots on the scanning surface of the optical disk to form the respective leading and trailing scanning spot on the surface of the optical disk is further configured to direct the reflected light to the corresponding ones . The controller circuit by processing the front end rear end scanning spot is scanning spot associated with the reflected light prior to reaching the surface defect is configured to identify the surface defect of the optical disk . ;