| 摘要 |
An optical pick-up including a fold mirror (540) having an achromatic quarter-wave plate coating (592) is provided. To allow the thin film coating to efficiently provide the quarter-wave retardation, the optical pick-up is configured such that the polarization of light incident on the fold mirror (540) is at a predetermined angle. According to one embodiment, the predetermined angle is provided by rotating the light sources. According to another embodiment, the predetermined angle is provided by rotating a plane containing the light sources and the beam combiners. In each embodiment, the beam combiners (530) and the fold mirror (540) are arranged along the same axis to further improve efficiency. |
