| 摘要 |
PURPOSE:To measure the reflection factor of an optical disk which has pregrooves in consideration of scattering and diffraction by the pregrooves by converging laser light into a fine spot and focusing it on a groove or between grooves. CONSTITUTION:Linear polarized laser light emitted by a semiconductor laser 4 is collimated by a collimator lens 5, passed through a beam shaping prism 6 and a polarization beam splitter 7, and polarized circularly by a quarter- wavelength plate 8, and the circularly polarized light is passed through an objective 8 and a substrate 1 and focused on an optical recording medium 2 as the fine spot of about 1mum in beam diameter. Reflected light from the optical recording medium 2 is converged by the objective 9 and becomes linear polarized light again by passing through the quarter-wavelength plate 8, and the light is reflected by the polarization beam splitter 7 and detected by a photodetector 10 as an RF signal. |
