| 摘要 |
PURPOSE:To prevent an S/N from being largely deteriorated in a base having a double refraction by splitting a reflected light beam into two in axis symmetry, inverting one light beam horizontally in a direction orthogonal to a symmetrical axis and overlapping the two light beams at the position of an analyzer. CONSTITUTION:An emitted light from a semiconductor laser 1 forms a spot to a recording medium 6 formed on a base 5 through a collimate lens 2, two beam splitters 3 and a condenser lens 4. The reflected light from the recording medium 6 is split by the beam splitter 3, divided into two by a split lens 14, transmitted through the analyzer 8 at the overlapped position and the transmitted light is detected by a photodetector 9. Thus, the deterioration in the S/N is less even with a base having a large double refraction. |
