| 摘要 |
PURPOSE:To attain a high-reliability device by sticking a 1/4 wavelength plate to the end part on the side, which does not face an information recording carrier, of a holding body of an aperture lens system to prevent irregularity of refractive index and degradation of isolation characteristics which are based on ununiformity of the internal stress after sticking of an optical adhesive. CONSTITUTION:A device consists of a light source 1 such as a semiconductor laser, a collimator lens 2, a polarizing beam splitter 3, an aperture lens system 5, an astigmatism lens system 7, a 4 divided optical signal detector 8, etc. The aperture lens system 5 consists of three lenses 51, 52, and 53 an objective holding body 54 holding these lenses, and a 1/4 wavelength plate 6. A step is provided in a part corresponding to an end part 55 in the side, which faces the polarizing beam splitter 3, of the objective holding body 54, and the 1/4 wavelength plate 6 is stuck to this step by an adhesive. The 1/4 wavelength plate 6 is stuck to the end part 55 in the side of the polarizing beam splitter 3 of the objective holding body 54 in this manner to improve isolation characteristics, and a stable servo system of information recording and reproducing is constituted. |
