A DISC DEVICE AND A DISC-LIKE RECORDING MEDIUM

摘要

The optical disc (1) has a record track (2), on which servo signal regions (3) and address signal regions (4) are formed alternately along the circumference. Two or more records using different physical changes are provided for the address signal regions (4), yet each region has only one means of physical change. For instance, one region is recorded in the form of pits and the next one is recorded opto-magnetically. switching between the two units is made when the pick-up is in the servo signal region, so leaving enough time margin for the operation.