Abstract: An optical disk apparatus has a rotation section rotates an optical disk having a photoimageable layer that is made imageable by laser light, a pickup section having a laser radiation section, a driving section of the pickup section, an irradiation driving section supplies a driving current in a continuous pulse mode to drive the laser radiation section to irradiate onto the photoimageable layer, a generating section generates drive information for the pickup section and the irradiation driving section in accordance with gradation information per rotation of the optical disk, the gradation information being obtainable by receiving image information and transforming the image information, and a control section controls gradation of a visualized image in accordance with a driving current in the continuous pulse mode by controlling the driving section and the irradiation driving section.

Abstract: An optical disk apparatus comprises a rotation section which rotates an optical disk having a photoimageable layer that is made imageable by laser light, a pickup section having a laser radiation section, a driving section for the pickup section, an irradiation drive section for the laser radiation section, an input section which inputs image information that is gradation information per rotation path of the optical disk and that is compressed to be represented by a differential component between gradations of adjoining rotation paths, and an expanding section (compressing section) which restores the differential component between the gradations of the adjoining rotation paths from the input section to original gradation information per rotation path of the optical disk. The restored gradation information per rotation path is received, and a label image is formed on the disk in accordance with the received gradation information.

Abstract: Pits and lands which have a pit length of 3T, a land length of *6T, a pit length of 7T, a land length of *3T, a pit length of 6T and a land length of *7T are alternately formed in a lead-in area in an inner track area on an optical disk as a test pattern for evaluating a read error of the optical disk. This test pattern data is reproduced by a reproducing system to detect an error rate, a compensation coefficient for minimizing the error rate is acquired, and a reproduction signal is compensated by using this compensation coefficient so that the reproduction signal is reproduced with the minimized error rate by the reproducing system.

Abstract: Pits and lands which have a pit length of 3T, a land length of *6T, a pit length of 7T, a land length of *3T, a pit length of 6T and a land length of *7T are alternately formed in a lead-in area in an inner track area on an optical disk as a test pattern for evaluating a read error of the optical disk. This test pattern data is reproduced by a reproducing system to detect an error rate, a compensation coefficient for minimizing the error rate is acquired, and a reproduction signal is compensated by using this compensation coefficient so that the reproduction signal is reproduced with the minimized error rate by the reproducing system.

Abstract: Pits and lands which have a pit length of 3T, a land length of *6T, a pit length of 7T, a land length of *3T, a pit length of 6T and a land length of *7T are alternately formed in a lead-in area in an inner track area on an optical disk as a test pattern for evaluating a read error of the optical disk. This test pattern data is reproduced by a reproducing system to detect an error rate, a compensation coefficient for minimizing the error rate is acquired, and a reproduction signal is compensated by using this compensation coefficient so that the reproduction signal is reproduced with the minimized error rate by the reproducing system.

Abstract: An optical disk apparatus includes a semiconductor laser for emitting a light beam, and an automatic power control or APC circuit for driving the laser. A compound prism structure is optically coupled to the laser in an optical head section, and defines a first optical path for causing a front laser light to be projected onto a rotating optical disk and guiding a reflected light therefrom toward a first photodetector, and a second optical path for guiding a part of the reflected light toward a second photodetector. An output signal of the first photodetector is used to generate a reproduced information signal. An output signal of the second photodetector is fed back to the APC circuit as a front light monitor signal. A part of a laser control signal internally generated in the APC circuit is supplied through a wiring line to a noise reduction circuit as a laser noise monitor signal.