| 摘要 |
PURPOSE:To make the S/N ratio of read signals higher and, at the same time, to prevent deterioration of an optical information recording medium, by irradiating a laser light of a frequency higher than the reading frequency upon the optical information recording medium at the time of reproduction. CONSTITUTION:In this optical disk device, a semiconductor laser 1 is driven at a duty ratio 50% when information is reproduced and an output B having power which is about twice conventional fixed output power A is intermittently emitted at a duty ratio 50%. The quantity of light C reflected at this time in accordance with the condition of pits 9 provided on an optical disk 6 becomes larger than the conventional reflecting quantity of light D and is intermittent at a duty ratio 50% and, therefore, information signals recorded by means of the pits 9 are detected when detected signals from a photoreceptor element 7 are peak-held. The S/N ratio of this information signal becomes sufficiently high because the peak of the reflecting quantity of light C is high and, at the same time, deterioration of the optical disk can be prevented since the quantity of exposure of the optical disk is not changed from conventional ones. |
