Optical disc reading system

摘要

The present invention provides a reading system for reading a writable optical disc having an information writing track, and a guiding track for introducing a laser beam to the information writing track wherein noises included in the prepit information is removed. The reading system comprises a photodetector having two photodetecting elements divided by a line optically parallel with a radial direction of the disc for detecting reflected light of a laser beam reflected from the information writing track, prepit signal producing means for producing a difference signal as a first prepit signal, from outputs of the divided photodetecting elements, added signal producing means for producing an added signal (C) of outputs of the divided photodetecting elements, noise cancel signal producing means for producing a noise cancel signal (C) based on the added signal, and noise extracting means for subtracting the noise cancel signal from the first prepit signal to produce a second prepit signal without noises caused by the added signal. <IMAGE>