Abstract: An optical disk device comprises a power ratio setting circuit for setting ratio of recording power to erasing power in a predetermined ratio, a recording start point detection circuit for detecting a recording start point by performing at least two cycle recording over the same area in a predetermined test region to detect a recording power and an erasing power of the recording start point, and a power setting circuit for setting a final recording power and erasing power for recording in a user region of the optical disk by multiplying the recording power and the erasing power of the recording start point by predetermined values respectively.

Abstract: An optical disk device comprises a power ratio setting circuit for setting ratio of recording power to erasing power in a predetermined ratio, a recording start point detection circuit for detecting a recording start point by performing at least two cycle recording over the same area in a predetermined test region to detect a recording power and an erasing power of the recording start point, and a power setting circuit for setting a final recording power and erasing power for recording in a user region of the optical disk by multiplying the recording power and the erasing power of the recording start point by predetermined values respectively.

Abstract: A write laser power setting device for setting a write laser power for writing data on a recording medium, includes first and second oscillators and for producing carrier signals having high frequencies f1 and f2. The carrier signals are added with each other to produce a sum signal which is applied to a laser driver for producing a laser drive signal. The power of the laser drive signal is changed to various levels. Using the laser drive signal, the write/read head writes test signals at preselected areas on the recording medium such that different writing power levels are applied to different preselected areas, respectively. After writing the test signals, the write/read head reads the recorded test signals. From the read signal, an unwanted signal having a frequency f1-f2 is filtered, and the level of the unwanted signal is detected and stored. A minimum level of the stored levels is selected, and a preselected area at which the minimum level reading is obtained is detected.

Abstract: A disk-type recording medium having circular or spiral tracks storing information. The tracks are radially and regularly spaced from one another. Each track has pregrooves (2), ridges, or protrusions, and discrete depressions (7,9), ridges, or protrusions. The depressions (7,9) are so disposed that the depressions of neighboring tracks do not neighbor one another. In playback, the depressions (7,9) of neighboring tracks do not cause crosstalk. Thus, the disk permits the identifying signals to be stably and correctly reproduced.