| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical pick-up device for recording and reproducing a BD, an HD DVD, a DVD, and a CD by using a common objective lens. <P>SOLUTION: The optical pick-up device 100 is provided with first, second and third light sources 1A, 1B and 1C for emitting light of 405 nm, 660 nm and 790 nm. A luminous flux of 405 nm is converged by a coupling lens 3A, a luminous flux of 660 nm is parallelized by a coupling lens 3B, and a luminous flux of 790 nm is diverged by a coupling lens 3C, and made incident on an objective lens 10 and forms a spot on each disk surface. A step structure is formed on lens surface 11 of the objective lens 10, the action of the step structure and arrangement of satisfying a predetermined magnification correct a spherical aberration that occurs due to a wavelength difference and a change in the thickness of a protective layer, and suppress the amount of a spherical aberration due to a temperature change. <P>COPYRIGHT: (C)2009,JPO&INPIT |
