Patent ID: 7706216
Filing Date: 2010-04-27
Classification: G11B

Abstract:
1. An optical head for reading and/or writing data from/on a storage medium, the optical head comprising: a light source; an objective lens for focusing light, which has been emitted from the light source, onto a track of the storage medium; light receiving means including at least one light receiving area for receiving a luminous flux of reflected rays, which have been reflected from the storage medium, thereby outputting a light quantity signal representing quantity of light received; and tracking error signal generating means for generating a tracking error signal based on the light quantity signal, wherein the luminous flux of reflected rays includes a first type of reflected rays where zero-order and first-order components of the light diffracted by the track are superposed one upon the other and a second type of reflected ray consisting essentially of the zero-order components, and wherein the light receiving area receives both the first type of reflected rays and the second type of reflected rays, and wherein the light receiving area receives center sections of the first type of reflected rays, and wherein as measured in a first direction in which the first type of reflected rays are arranged, the light receiving area has a size that is equal to or greater than the diameter of the luminous flux of reflected rays, and wherein as measured in a second direction perpendicular to the first direction, the light receiving area is narrower than a width of the first type of reflected rays.