| 摘要 |
PURPOSE:To prevent a polarized light phase difference from being caused by allowing readout light to be reflected in a couple of full reflecting mirrors sequentially. CONSTITUTION:The readout light radiated from a semiconductor laser 3 passes through a polarized plate 4 to be P polarized light and the light transmitted through a PBS 5 becomes P+S polarized light by a lambda/4 plate 6, reflected in both prisms 1, 2 and made incident in the optical disk face. The light reflected in the optical disk face is reflected again in two prisms 1, 2, the optical path is transferred and becomes an S polarized light through the lambda/4 plate 6, is reflected in the PBS 5 and made incident in a photodetector PD 7. The readout light is subjected to optical axis change in the P+S polarized state in the said optical path, but since the polarized phase difference caused at each reflection is cancelled, the readout accuracy is not deteriorated. |
