| 摘要 |
PURPOSE:To prevent the generation of a crosstalk caused by an influence of an adjacent track, by providing a light absorbing film on one refracting surface of an objective lens, and forming this light absorbing film so that its thickness becomes thinner in the center part containing an optical axis. CONSTITUTION:A light absorbing film 23 is provided on one refracting surface of an objective lens 21 for focusing an irradiating light emitted from a light emitting element 1, to a recording surface of a disk 13. Thickness of this film 23 is thin in the center part containing an optical axis. By providing such a film 23, a light quantity distribution of a spot light focused to the recording surface of the disk 13 goes to a Gaussian distribution. Accordingly, this light quantity distribution has no side lobe, and when reading an information signal by making this spot light follow up and information recording track, a crosstalk by an influence of an adjacent track is scarcely generated. |
