| 摘要 |
<P>PROBLEM TO BE SOLVED: To obtain an objective lens capable of more raising the detection accuracy of detection system of an optical pickup device adopting the objective lens which is constituted of; a 1st region where diffraction structure is formed including an optical axis; a 2nd region where a refraction surface of the outer side of the 1st region is formed; and a 3rd region where diffraction structure of the outer side of the 2nd region is formed. <P>SOLUTION: The objective lens is configured so that 1st and 2nd luminous fluxes which pass the 1st region contribute to the formation of 1st and 2nd condensed spots respectively and the 1st and 2nd luminous fluxes which pass the 2nd region do not contribute to the formation of the 1st and 2nd condensed spots respectively, the 1st luminous flux which passes the 3rd region contributes to the formation of the 1st condensed spot and the 2nd luminous flux which passes the 3rd region does not contribute to the formation of the 2nd condensed spot. <P>COPYRIGHT: (C)2007,JPO&INPIT |
