| 摘要 |
PURPOSE:To obtain a compact optical head to be easily formed by emitting a laser beam guided into a waveguide from plural divided gratings and setting up respective 1/2 wavelength plats so as to form prescribed angles with divided radiation beams. CONSTITUTION:Light from a laser diode 40 is converted into a circularly polarized light through a hologram element 36 and a 1/4 wavelength plate 33 and made incident upon the 1st grating (FGC) formed on a transparent base 31. The incident light is guided into an waveguide 32 and emitted so as to be converged by plural divided circular FGCs 25a, 25c arranged on the outside of the base 31. The 1/2 wavelength plates 34, 35 are arranged so that their optical axes coincide with the center polarizing direction of polarized beams radiated from the zone of several FGCs 25a, 25c. Consequently, the deflecting direction is rotated by 90 deg. and convergence can be attained in the matched state of the polarizing face. The converged beam is reflected on the recording face of an optical recording disk and returned through the reverse optical paths and focus error signals are obtained by photodiodes 37, 38. Consequently, the optical head can be compacted and easily produced. |
