| 摘要 |
<P>PROBLEM TO BE SOLVED: To focus light beams on an information recording surface with high light utilization efficiency for each of a plurality of kinds of optical recording media with transparent substrates different in thickness. <P>SOLUTION: A light pickup optical system reads information of three kinds of optical recording media. The system has a wavelength selective filter 6. The wavelength selective filter 6 includes an outer area for shielding only one light beam of light beams having respectively three kinds of wavelengths and an inner area for allowing all the light beams to pass through. The system also has an objective lens 1 that focuses each light beam having passed through the wavelength selective filter 6 on each light recording medium. An optical head and an optical disk apparatus have the optical pickup system like this. <P>COPYRIGHT: (C)2007,JPO&INPIT |
