Patent ID: 7522484

Claim:
An optical information processor for at least one of reading information from a storage medium and writing information on a storage medium by irradiating the storage medium with light that has been radiated from a light source, the optical information processor comprising: the light source for radiating the light; a condensing element for converging the light, radiated from the light source, toward the storage medium; and a detector for detecting a portion of the light that has been radiated from the light source, wherein in a far-field pattern of the light radiated from the light source, an aperture area A is defined by a part of the light entering the condensing element and a photosensitive area B is defined by another part of the light entering the detector and the light has the narrower angle of radiation in an x direction and the wider angle of radiation in a y direction, respectively, and the center of the photosensitive area B in the x direction is offset with respect to that of the far-field pattern in the x direction.