| 摘要 |
PROBLEM TO BE SOLVED: To make it possible to increase the recording density as much as possible. SOLUTION: An optical device is equipped with a light beam forming means 3 which forms light beams, a prism 8 for receiving the optical beams formed by this optical beam-forming means and changing the direction of the optical beams and an objective lens 10 for receiving the light beam from this prism 8 and forming an optical spot on a recording surface of an optical disc 1. One out of the prism 8 and the objective lens 10 is constituted of a nonlinear optical crystal material. |
