| 摘要 |
PURPOSE:To miniaturize an optical pickup and to make it light weight, by constituting a lens of a cyclical irregular shape formed on the surface of a substrate, and arranging a photodetector on the same substrate by inclining the optical axis of the lens against the normal of a recording medium. CONSTITUTION:The lens 102 on which irregularity is provided by etching is provided on the surface of a part of a glass substrate 101, and the plane shape of the lens 102 is formed concentrically, and the lens is formed in such a way that the more the radius increased, the shorter becomes the cycle. Convergent light 106 is changed to reflected light 108 including the information of the recording medium 107, and is inputted to the photodetector 103 whose photoreceiving plane is divided quarterly. The photodetector 103 is bonded on the glass substrate 101. A semiconductor laser 104 and the lens 102 make the angle with the normal 110 of the recording medium 107, therefore, the optical axis of the reflected light 108 also makes the angle wit the normal 110, and no reflected light 108 returns to the semiconductor laser 104. In such a way, it is possible to obtain a miniaturized and light optical pickup. |
