| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical pickup device in which tracking adjustment is easily conducted by a tracking signal whose offset voltage is eliminated, even though the position of a lens 6 is moved with respect to an optical recording medium 8. <P>SOLUTION: The optical pickup device conducts tracking control and has: a semiconductor laser 1; a condenser lens 6; a composite diffraction element 10 which has a plurality of diffraction divided surfaces that receive reflected light beams 13 being reflected from an optical recording medium 8, diffracted and generated and diffract and divide the beams 13 into a plurality of light beams; an optical detector 11 which receives the plurality of diffracted and divided light beams so as to convert the beams into electric signals; and a push-pull circuit 14 which receives electric signals from the optical detector 11 and outputs a tracking signal. The composite diffraction element 10 having the plurality of diffraction divided surfaces, divides the portion where the zero-order light beams and the ±first-order light beams among the reflected light beams 13 generated from the optical recording medium 8 are overlapped, into two, and emits the one to the optical detector 11 and the other to the outside of the optical detector 11, and also emits only the portion of all zero-order light beams of the reflected light beams 13 generated from the optical recording medium 8 to the optical detector 11. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
