Patent ID: 7606135
Filing Date: 2009-10-20
Classification: G11B

Abstract:
1. An optical recording/reproducing apparatus, comprising: a plurality of light sources emitting lights with different wavelengths for use in recording/reproducing information onto/from various types of optical recording media of different recording densities, in which at least two lights emitted from the plurality of light sources have polarization components orthogonal to each other; an objective lens focusing the lights from each of the plurality of light sources to the corresponding one of the optical recording media; a collimating lens disposed between the plurality of light sources and the objective lens collimating the lights from the plurality of light sources; a hologram element installed between the collimating lens and the objective lens, refracting a light emitted from one of the plurality of light sources, in which the light to be refracted is selected by wavelength and polarization components; a photodetector receiving the light that is reflected from the corresponding optical recording media after being focused by the objective; and a λ/4 wavelength plate between the objective lens and the hologram element, and wherein the plurality of light sources comprise: wherein the hologram element diffracts the p-polarized light with the first wavelength, and wherein the s-polarized lights emitted from the second and third light sources and transmitted through the hologram element are changed into right-circularly polarized lights by the λ/4 wavelength plate, reflected from the optical recording media and changed into left-circularly polarized plates.