| 摘要 |
<p>Provided are an objective lens for an optical pickup device, an optical pickup device using the same, and an optical information recording and reproducing device which allow three types of optical disks including BD, DVD and CD to be replaceable by means of a common objective lens with no restriction on optical magnification while allowing for greater design freedom, high efficiency, and excellent manufacturability. A second optical path difference giving structure provided on the intermediate region of an objective lens is a step-like structure wherein the number of steps for each annular zone is identical. The second optical path difference giving structure sets the amount of zero-order diffracted light of a first luminous flux that passed through said second optical path difference giving structure to be greater than the amount of any order diffracted light and sets the amount of first-order diffracted light of a second luminous flux that passed through said second optical path difference giving structure to be greater than the amount of any order diffracted light. Further, said second optical path difference giving structure sets the amount of first-order diffracted light of a third luminous flux that passed through said second optical path difference giving structure to be greater than the amount of any order diffracted light.</p> |
