| 摘要 |
PROBLEM TO BE SOLVED: To provide the optical head device capable of reading and writing whichever an optical disk is a compact disk(CD) or a digital video disk(DVD) by utilizing different polarizing directions of a light beam for these two kinds of disks. SOLUTION: A light beam LB emitted from a light projecting part is transmitted through an annular polarizing filter 10. Since an S-polarizing component out of the light beam LB transmitted through the polarizing filter 10 is transmitted through the polarizing filter 10, while a P-polarizing component is intercepted by the polarizing filter 10, light of the S-polarizing component is transmitted through the polarizing filter 10 and is converged by an objective lens 6 as the light of a large numerical aperture so as to be converged on the DVD. Then, light of the P-polarizing component is transmitted through the polarizing filter 10 and is converged by the objective lens 6 as the light of a small numerical aperture so as to be converged on the CD. The light beam LB reflected by the DVD is transmitted through a polarizing beam splitter 11 and is received by a photodiode 7 for the DVD, while the light beam reflected by the CD is reflected by the polarizing beam splitter 11 and is received by a photodiode 8. |
