| 摘要 |
PROBLEM TO BE SOLVED: To improve signal quality by increasing the signal light quantity of a light beam for information detection emitted from a prism with a beam splitter. SOLUTION: This optical recording and reproducing device includes a quarter- wave plate 29 for converting the light beam reflected by or transmitted through the joint surfaces 30 of the prism 23 with a beam splitter and made incident on an objective lens to circularly polarized light. The joint surfaces 30 are formed of polarizable films having polarization characteristics in such a manner that the reflectivity or transmittance of the light beam reflected by or transmitted through the joint surfaces 30 and made incident on the quarter-wave plate 29 is larger than 50% and that the transmittance or reflectivity at the time of transmission or reflection through or by the respective joint surfaces 30 after the reflection by the disk is larger than 50%. |
