Abstract: There is provided a disk drive unit which is capable of making control corresponding to contaminant and defect by discriminating the contaminant (dust, scratch) on the disk surface from the defect on the recording plane. In a pull-in signal PI corresponding to reflected light from a disk, a defect detecting signal corresponding to a signal whose level change is relatively quick corresponding to the defect of the recording plane and a contaminant detecting signal which corresponds to a signal whose level change is relatively slow corresponding to the contaminant on the disk surface are generated. When the defect detecting signal is at low level for example, a system controller retries a recording operation or increases laser light when the contaminant detecting signal is at low level. A quantity of output light of a laser diode is controlled so that a product of output light of a laser diode and reflected light from the disk amounts to a predetermined level.

Abstract: An optical recording medium is described, having suitable recording characteristics over a wide range of recording linear speed and fitting with recording/reproduction apparatuses of CD-R specifications. The optical recording medium includes a substrate having at least a light absorbing layer thereon, which is mainly composed of three phthalocyanine compounds (I), (II) and (III). Each of the phthalocyanine compounds (I) and (II) has a thermal decomposition temperature of from 200° C. to 300° C., and has a different light absorption ability against light having a wavelength of 780 nm. The phthalocyanine compound (III) has a thermal decomposition temperature of from 300° C. to 350° C.