METHOD FOR REPRODUCING SIGNAL IN OPTICALLY RECORDING MEDIUM.

摘要

A method for reproducing signals in an optically recording medium of the type in which recording pits are erased or embossed by the temperature rise of the medium caused through projecting a light beam for reading out signals, or of the type in which the reflection factors of recording pits are changed by the temperature rise of the medium caused through projecting a light beam. The variation of the substantial size of the reproducing region because of the change of the temperature of the medium is prevented. For this prevention, for example, a temperature sensor (20) for sensing the temperature of a magnetooptical disc (11) is provided. By controlling the laser power and the external magnetic field according to the temperature sensed by this temperature sensor (20), the substantial size of the reproducing region is kept constant always.