Patent ID: 8576684

Claim:
An optical pickup comprising: a light source unit that is configured to emit light having a plurality of different wavelengths which are suitable for at least one of recording data to and reproducing data from a plurality of information storage media; a diffraction device comprising a plurality of diffraction patterns corresponding to the plurality of different wavelengths, the diffraction device being configured to divide light incident from the light source unit into main light and sub light; an objective lens that is configured to focus incident light so as to form an optical spot for at least one of recording data to and reproducing data from of an information storage medium; and a photo-detector comprising a first main light reception unit that is configured to receive the main light and a first sub light reception unit that is configured to receive the sub light to detect at least one of an information signal and an error signal, by receiving light reflected from the information storage medium, wherein the first sub light reception unit of the photo-detector is formed in a pattern such that an area, on which noise sub light is incident, is shaped to comprise a circular or semi-circular recessed area so as to reduce reception of the noise sub light due to diffraction based on an undesired diffraction pattern of sub light being generated by the diffraction device.