Patent ID: 6947213
Filing Date: 2005-09-20
Classification: G02B,G11B

Abstract:
1. An optical pickup that optically reads information that has been recorded on an optical recording medium, comprising: laser beam exposing means which includes a light source that emits a laser beam and focuses the laser beam on an information recording surface of the optical recording medium; a first polarizing beam splitter for splitting light reflected back off the information recording surface into first polarized light and second polarized light that is polarized in a different direction to the first polarized light; and photoelectric conversion means for receiving the first polarized light and the second polarized light and converting the first polarized light and the second polarized light into electrical signals, wherein the first polarizing beam splitter includes: a first substrate with a first main surface and a second main surface, a refractive index of the substrate being equal to n where n is a value greater than one; a first diffractive optical element pattern that is formed on part of the first main surface with a pattern pitch Λ such that λ/n<Λ≦λ, where λ is a wavelength of the reflected light; and a second diffractive optical element pattern that is formed on one of the first main surface and the second main surface at a predetermined position on an optical path that diffracted light produced by the first diffractive optical element pattern takes within the first substrate.