| 摘要 |
PROBLEM TO BE SOLVED: To prevent crosstalk from the adjacent tracks of the optical pickup provided with hologram lens. SOLUTION: The whole surface of one surface of an objective lens 10 is made to be a hologram lens forming surface 11. The hologram lens at the center part of the hologram lens forming surface 11 and the hologram lens at the peripheral part of the surface 11 are made physically different from each other. Consequently, the laser beam diffracted in the center part of the surface 11 is converged on an A plane and the laser beam diffracted in the peripheral part of the surface 11 is guided to an outer side. Thus, since the light intensity distribution after being passed through the objective lens 10 becomes almost uniform to eliminate the generating of a first order ring, crosstalk from the adjacent tracks is prevented from occurring. |
