OPTICAL HEAD DEVICE

摘要

A 3-beam-generating grating 2, a collimating lens 3, a polarizing beam splitter 4, a rising mirror 5 and an objective lens 6 are arranged sequentially in the optical path between a semiconductor laser device 1 and an information recording medium 7. The reflecting face of the polarizing beam splitter 4 has a reflection characteristic such that the reflectance is minimum for return light L2 at an angle of 45 degrees whereas the reflectance increases as the incident angle of the return light L2 deviates from 45 degrees. This realizes an optical head device that is not likely to cause the decrease in tracking error signals even if the objective lens shifts in radial directions of the recording medium. <IMAGE>