| 摘要 |
PURPOSE:To provide an optical head formed in such a manner that the distribution (side lobe) of the annular band-shaped light generated on the outside of a light spot is made small by diminishing the NA in the radial direction of an objective lens. CONSTITUTION:This optical head includes a semiconductor laser which supplies a light beam and the objective lens 23 which converges the light beam supplied from this semiconductor laser by passing the light beam through an aperture 51 and supplies the light beam to an optical disk 25. The shape in the opening 51 of the objective lens 23 is made elliptic and its major axis is approximately aligned to the circumferential direction of the optical disk 25 and its minor axis is approximately aligned to the radial direction of the information recording medium. |
