| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical pickup which is so constituted that the reflecting surface of a glavanomirror and the front focus of an objective lens have an accurately conjugate relation. SOLUTION: This optical pickup is provided with a semiconductor laser 12 which emits a light beam, a galvanomirror 18 which deflects the light beam, a relay lens 14 which is arranged between them and a light convergence optical system which converges the light beam from the galvanomirror 18 on a recording medium 44. The light convergence optical system has a parallel flat plate 70, an imaging lens 32 which converts the light beam from the galvanomirror 18 to parallel light, a raised mirror 34 which reflects the collimated light beam, and an objective lens 36 which converges the reflected light beam. Parallel flat plates which have the same refractive index, but differ in thickness are prepared as the parallel flat plate 70. The parallel flat plate which minimizes the movement of luminous flux at the front focus of the objective lens 36 when the galvanomirror 18 is swung is selected out of them. |
