| 摘要 |
PURPOSE:To restrict the noise caused by reflected feedback incident light by a method wherein an optical system is provided so that polarizing direction of the emitting light outputted from a laser element and the reflected feedback light thereof may intersect almost perpendicularly with each other. CONSTITUTION:The outgoing light outputted from a laser element 1 is radiated after being converted into parallel light by a collimator lens 2 passing through a beam splitter 3 and a quater wave length plate 4. The polarizing direction of the emitting light from the laser element 1 is set up to be perpendicular to the emitting direction as shown by the arrows. The linear polarization of the emitting light becomes circular polarization after passing the quater wavelength plate 4. The light reflected from a disc become the linear polarization again after reading the emitting channel reversely and passing the quater wavelength plate 4 but the polarizing direction will be perpendicular to that of the emitting lights from the laser element 1. The light is partially become perpendicular but after passing the beam splitter 3, proceed to an optical system for reading to feedback the remaining light to the laser 1. The feedback light to the laser element 1 may become equivalent to natural light for the laser element 1 since the emitting light from the laser element 1 is perpendicular to the polarizing direction. |
