| 摘要 |
PURPOSE:To correctly detect information without being affected with a beat signal by making the interval of the frequencies of each high frequency current source larger than that of the frequencies of the information recorded on an information recording medium. CONSTITUTION:Plural direct current sources 32, 42, 52 and 62 to supply direct currents to the respective light emitting points of a semiconductor laser 21 and plural high frequency current sources 33, 43, 53 and 63 to supply high frequency currents superimposed on the direct currents are provided. Further, the interval of the frequencies of the plural high frequency current sources 33, 43, 53 and 63 is made larger than that of the frequencies of the information recorded on an information recording medium 6. Thus, the beat signal can be easily separated from the information recorded on the information recording medium 6, and the information can be correctly detected without being affected by the beat signal. |
