| 摘要 |
PURPOSE:To obtain an optical pickup which has high accuracy and high reliability and is small in size and weight by disposing optical elements of the optical pickup by utilizing the spacing between two pieces of grating lenses. CONSTITUTION:This pickup is basically constituted of the grating lens optical system and a hologram 31 which bisects signal light and takes out and converges the split beams of light to the outside of the optical axis is provided between the 1st grating lens and the 2nd grating lens. The flat plate hologram 31 is disposed in parallel with the grating lenses 11, 12 and has a function as a half mirror or polarized beam splitter. The optical parts except a light source P and photodetectors 43, 44 are thus easily integrated by stacking of the flat plates and since the processing of signals can be executed within the thickness of the wavelength non-sensitive type grating lens system corresponding to the thickness of the conventional optical lens, the scale of integration of functions is improved and the optical head which is small in size and weight is constituted. |
