| 摘要 |
PURPOSE: To correctly compensate wavelength variations and to obtain a broad tolerance by running a dividing line of a detector pair parallel to a line linking the center of a radiation emission surface of a laser diode and the center of a complex radiation detection system. CONSTITUTION: Track 3 is located in an information surface 2 on an optical recording medium 1. the information surface is scanned by a beam b emitted from a diode laser 4. This beam is converged within the information surface 2 by an objective lens system 6. The reflected beam (b) is detected by a reflection sensing complex detection system 10 through a diffraction grating 9, and the detection system is comprised of photo-diodes 18, 19 and 20, 21 divided by dividing lines 22, 23. The dividing lines 22 and 23 are stretched at angles of +ψ and -ψ respectively to the connection line CL between the original point O and the center of the detector 10, and the connection line CL coincides with the dividing line 24 between the detector pairs 18, 19 and 20, 21. |
