| 摘要 |
PURPOSE:To obtain a signal detection system where a reproduced signal is less degraded by allowing the main lobe component of a spot condensed again to mainly include the reflected light from the main lobe on a recording medium. CONSTITUTION:The light emitted from a semiconductor laser 1 passes a collimator lens 2, a light shielding band 3, and beam splitters 4-1 and 4-2 to form a super-resolution spot on a recording medium 6 by a condensing lens 5. The reflected light from this spot is divided into two by splitters, and one forms a spot on a divided photodetector 8 by a converging lens 7, and the other is led to an error detecting optical system 9. A main spot 10 is formed on a detecting part 14 of the detector 8, and two side spots 11 are formed on detecting parts 15 and 16 of the detector 8, and a detection signal (a) of the detecting part 14 and a detection signal (b) of detecting parts 15 and 16 are obtained. The reflected light from the main lobe on the recording medium is mainly included in the main lobe component of this spot condensed again. Consequently, the reproduced signal of less passing-round from side lobes is obtained by the signal (a). |
