Abstract: Disclosed is a method of recording information on a magnetooptical recording medium, which medium includes a first magnetic layer and a second magnetic layer having a lower Curie temperature and a higher coercive force at room temperature than those of the first magnetic layer. The second magnetic layer is exchange-coupled to the first magnetic layer. The first magnetic layer has a higher compensation temperature than the Curie temperature of the second magnetic layer. The method of recording information includes applying a magnetic field, which is modified in accordance with information from a magnetic head, to the medium to record information on the first magnetic layer and scanning the medium with a light beam to heat the medium to a temperature at least near the Curie temperature of the second magnetic layer so as to transfer the information recorded on the first magnetic layer to the second magnetic layer.

Abstract: An optical head device comprises a light source, a light splitter for reflecting a light emitted from the light source by a first plane thereof to direct the light to an information carrier and transmitting the light from the information carrier through the first plane, a photo-detector for detecting the light from the information carrier, and a diffraction grating structure arranged on a second plane of the light splitter for diffracting the light transmitted through the first plane and directing it to the photo-detector.

Abstract: An information recording medium comprising a plurality of information tracks on which information is recorded, and separating regions for separating each of said information tracks from the other information tracks, each of said separating regions including a record section consisting of code of a shape or magnitude different from code in said information tracks.

Abstract: An information reproducing apparatus comprising a detecting device for detecting information recorded in a plurality of information tracks on a record carrier, and an extracting device for extracting correct information from the information detected by the detecting device. This extraction is executed by evaluating plural information detected from each information track to extract the most correct information from the information or by identifying the information track, the information of which is detected, to extract the correct entire information deteted from the information tracks.