| 摘要 |
PURPOSE: An objective lens and optical device are provided to correct both the on-axial aberration and the off-axial aberration when a plurality of optical disks such as DVD, CD and so on are recorded or read. CONSTITUTION: An objective lens includes first ringed step portions(11-15) arranged in a first surface of the objective lens, wherein the first ringed step portions have function to produce a phase difference with respect to light having a first wavelength. Second ringed step portions(21-26 ) are arranged in a second surface of the objective lens, and the second ringed step portion have function to produce a phase difference with respect to light having a second wavelength. In an optical device wherein light from a light source having different wavelengths with respect to two optical disks is converged to respective data recording surfaces of optical disks and reflection light from the respective data recording surfaces is received by a light receiving element in recording or reading the optical disks respectively, the above-described objective lens is used.
|
