Novel measuring technique of the optical performance of objective lenses for optical disk systems.

Methods for the novel calculation of aberrations in objective lenses that require diffraction-limited optical performance are proposed and discussed. Coma, astigmatism, and spherical aberrations are evaluated separately and quantitatively from the intensity distribution of spot images. The aberration values calculated from the spot images were found to correlate well with the experimental results from the wave-front aberrations measured by a laser interferometer. The measurements took only 12 s as a mean value. This is 10 times faster than the conventional method.