| 摘要 |
PURPOSE:To make the device small-sized and light, and to make simple the assembling and adjusting by providing a light dividing device to diffract the reflecting light from the recording media with the diffracting lattice and guide it to a photodetecting device, and further, forming at least a part of the optical element to constitute the converging means in a single body with the light dividing device. CONSTITUTION:The luminous flux irradiated from a semiconductor laser light source 11 is reflected by a bending mirror 30 and made incident on a light dividing device 32. The light dividing device 32 is composed of a parallel plate 16 and a collimator lens 31 to combine a diffracting lattice 15 formed on this and the cover glass of the diffracting lattice 15. The luminous flux made into the parallel light by the collimator lens 31 transmits the parallel plate 16, and is converged through a substrate 19 to an information recording carrier 20 by an objective lens 18. The luminous flux reflected from the information recording carrier 20 and including the information comes to be the parallel luminous flux through the objective lens 18, and after the flux is made incident on the parallel plate 16, the flux is diffracted by the diffracting lattice 15, while total reflection is executed in the parallel plate 16, the flux comes to be a luminous flux 22 and guided and is made incident on a photodetecting device 23 through an analyzer 21. Thus, the constitution comes to be simple and the position adjustment such as the optical axis alignment is easily performed. |
