| 摘要 |
PURPOSE:To reduce errors in detecting inclination and to miniaturize the reading device by integrally forming an optical integrated circuit type pickup and an inclination detector and making the irradiation point of a light beam approach. CONSTITUTION:The light beam from a semiconductor laser 2 is guided to a condensing grating coupler 3 through a master optical wave guide 4 so as to form a master beam spot 8. Simultaneously, the part of the light beam is respectively guided to 1st and 2nd subcouplers 100 and 102 through 1st and 2nd sub optical wave guides 104 and 105 and is diffracted so as to irradiate near the spot 8 and after being reflected on an information recording surface, the light beam is made incident on 1st subphotodetectors 101a and 101b and 2nd subphotodetectors 103a and 103b, and in the case that the recording surface and the coupler are inclined, the incident light of each photodetector is not equalized, so that the difference of an output voltage is generated and then, the inclined direction and quantity in turning around an X axis and a Y axis can be respectively detected in the 1st and 2nd subphotodetectors. |
