| 摘要 |
PURPOSE:To improve mass productivity and to reduce the cost in an optical information read-out device. CONSTITUTION:A semiconductor laser 42, photodiode 45, diffraction grating beam splitter 46, diffraction grating 49 for splitting into three beams and mirror 50, are arranged on the two surfaces facing each other of a blocklike transparent substrate 41. The inside of this transparent substrate 41 is used as an optical path, a slope 51 is formed on the lower surface 41b of the trailing end of the optical path, a mirror 52 is installed on the slope 51, and a convex objective lens 47 is formed on an upper surface 41a positioning on the upper part of this slope 51. A diffraction grating 48 is installed in a position adjacent to this convex objective lens 47, and further, a convergence lens is formed with the convex objective lens 47 and diffraction grating 48. |
