Preliminary pit detection device and information recorder therewith

摘要

The irradiation device (10, 15, 16) irradiates, at the time of recording main information, a first light beam having a first power and a second light beam having a second power on the pre-pits in a time-divisional manner. The light receiving device (10) receives a reflected light of the first light beam from the pre-pits to produce a first light-receipt signal, and receives a reflected light of the second light beam from the pre-pits to produce a second light-receipt signal. The first detector (19, 38) detects the pre-pits based on the first light-receipt signal to produce a first detection signal (Sge1), and the second detector (19, 39) detects the pre-pits based on the second light-receipt signal to produce a second detection signal (Sge2). Then, the processor (19, 42) produces a logical sum of the first detection signal and the second detection signal to output a pre-pit detection signal (Spd). Therefore, the pre-pits can be correctly detected in both cases where the first light beam and the second light beam is irradiated, and all pre-pits on the storage medium (1) may be detected to obtain the recording information. IMAGE