| 摘要 |
PROBLEM TO BE SOLVED: To use a diffraction element made of resin in a high-density optical disk system where a laser beam of large energy is used, while maintaining the accuracy in recording and reproducing an information signal in the optical disk.SOLUTION: In an optical pickup device of this invention, a light source 11 emits the laser light having a predetermined wavelength. And a diffraction element 12 has a lattice plane 12a having periodic recesses and projections, and reflects and diffracts the laser beam emitted from the light source 11, divides it into three beams composed of a main beam (zeroth order light) and a pair of sub-beams (+first order light and -first order light) and outputs them to a polarizing beam splitter 13. |
