| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical pickup device that is balanced so that the displacement of each diffracting light may be within a tolerance limit if each diffracting light is displaced in mutually different direction due to several erroneous factors. SOLUTION: A first acute angle θ2 that is made by the direction of a dividing line that divides a second photo acceptance area 9a-into several sub areas 23a, 23b, 23c and 23d and the radial direction 5, is smaller than a second acute angle θ1 that is made by a first diffracting direction 10a and the radial direction 5. When Δθ=θ1-θ2 means that a maximum value of an error in a position of diffracting light along the first diffracting direction 10a is a maximum diffracting direction error and a maximum value of an error in a relative position of the diffracting light along the radial direction 5 is a maximum radial direction error, the dimension of the displacement projecting the maximum diffracting direction error in the vertical direction of the dividing line in the second photo acceptance area 9a-by sin (Δθ) is equal to that of the displacement projecting the maximum radial direction error in the vertical direction of the dividing line in the second photo acceptance area 9a-. |
