| 摘要 |
<p>An optical pickup device is disclosed. In the optical pickup device, S-polarized light is input to a polarization filter from a DVD light source or a CD light source. Since the polarization filter transmits through the S- polarized light and diffracts P-polarized light, the S-polarized light is transmitted through the polarization filter. The S-polarized light is converted into three beams by being diffracted by a diffraction element. The three beams reflected at a polarization beam splitter are converted into circularly polarized light by a 1/4 wavelength plate via a collimate lens, and the circularly polarized light is condensed on an optical recording medium via an objective lens. Light reflected from the optical recording medium is converted into linear P-polarized light by the 1/4 wavelength plate via the objective lens. Substantially almost all P-polarized light is transmitted through the polarization beam splitter. A slight amount of the returning light travels to the side of the light source.</p> |
