| 摘要 |
PURPOSE:To simultaneously satisfy two conditions, that is, a simple constitution of an electric circuit and no degradation of the reproduction C/N with regard to a magneto-optical head device which uses a diffraction element for detection of the error and information signals. CONSTITUTION:The reflected light of a disk 5 is separated into three beams, i.e., a 0-order beam (normal light component) and the + or -1st-order diffracted beams (abnormal light component) by a polarizing simple diffraction grating 34 which chiefly diffracts only a specific polarizing component out of the incident light. The 0-order beam of the grating 34 is separated into three beams, i.e., a 0-order beam and the + or -1st-order diffracted beams by a polarizing hologram 35 which chiefly diffracts only the polarizing component orthogonal to the polarizing component of the grating 34 out of the incident light. Then the error signal is detected with use of a partial beam that is separated by the hologram 35 from the 0-order beam of the grating 34. Meanwhile the information signal is detected based on the difference between another beam separated from the 0-order beam of the grating 34 by the hologram 35 and the + or -1st-order diffracted beams of the grating 34. |
