| 摘要 |
<P>PROBLEM TO BE SOLVED: To suppress a decrease in the quantity of light for light (forward passage light) from a light source to an information recording medium and light (return passage light) from the information recording medium to a light receiving element, to miniaturize the optical pickup, and to speed up recording and reproduction speeds to the same level in comparison with a conventional optical pickup having an optical system in which an optical path is separated according to the wavelength. <P>SOLUTION: A first polarizing diffraction grating 11 for transmitting light having a wavelength of λ2 and diffracting light having a wavelength of λ1 by applying voltage, and a second polarizing diffraction grating 12 for diffracting light having a wavelength of λ2 and transmitting light having a wavelength of λ1 by applying voltage are provided on an optical path from a light source for emitting light having a plurality of wavelengths to the information recording medium to the light receiving element for receiving reflection light from the information recording medium. The strength of voltage applied to the first and second polarizing diffraction gratings 11, 12 according to the wavelength of light emitted from the light source is allowed to differ between the first and second polarizing diffraction gratings 11, 12. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
