Method and apparatus for reproducing and recording information on an optical disc and light detecting apparatus used in the reproducing apparatus.

摘要

An optical disc (2) has a recording surface on which a spiral track having a predetermined track pitch is formed. A plurality of information units are formed on the track each of which has a predetermined unit length in a circumferential direction and a radial direction of the optical disc respectively. The information is converted in a shape and a disposed position of an information pit, which is formed in each of the plurality of information units. A method of reproducing the information includes the steps of: irradiating a reading light to form a light spot on the information pit; detecting an outer light portion, which corresponds to an outer circumferential side domain, among a reflective light shaped in a spot from the information pit, which is projected on an imaginary plane including a light receiving surface of a light detecting apparatus (30) to output a light detection signal indicating the detected outer light portion; and reproducing the information on the basis of the light detection signal. <IMAGE>