| 摘要 |
PROBLEM TO BE SOLVED: To provide a focus error detection device and an optical pickup device such that positioning of a diffraction element is made easy and stable focus control can be performed.SOLUTION: A light receiving element 2 includes a focus light receiving region that is divided into focus light receiving regions 2a and 2b by a division line. A diffraction element 4 includes: in a focus state, diffraction regions E that diffract a part of reflection light emitted from a light source 1 and reflected from an optical recording medium 7 and form a spot on the division line; and diffraction regions E and F that diffract the other part of the reflection light toward the focus light receiving regions 2a and 2b and form spots at positions symmetrical with respect to the division line. |
