A write-once type information recording medium according to one aspect of the present disclosure includes at least one recording layer. In the information recording medium, the at least one recording layer has a spiral shape in which a land track and a groove track are alternately arranged as a recording track, the recording track is divided into blocks each of which being minimum unit in which recording is performed, and the information recording medium includes a management information area where management information is recorded and a user data area where user data is recorded. Each of the management information areas of both the land track and the groove track on each recording layer of the at least one recording layer is disposed at a same distance from the center of the information recording medium.

A mark corresponding to recording data is formed on an optical disk by: encoding the recording data in accordance with a modulation code and generating encoded data; classifying the encoded data by a combination of at least two of a mark length of a mark, a space length of a preceding space, the mark length of a preceding mark, and the space length of a succeeding space; setting a correction amount for adjusting the position of the start edge and the end edge of a recording pulse based on an evaluation index of a decoding result, which is a result of decoding a reproduction signal of the encoded data, for each of the classification; and generating the recording pulse corresponding to the encoded data by using the correction amount corresponding to the classification of the run length of the encoded data.

A mark corresponding to recording data is formed on an optical disk by: encoding the recording data in accordance with a modulation code and generating encoded data; classifying the encoded data by a combination of at least two of a mark length of a mark, a space length of a preceding space, the mark length of a preceding mark, and the space length of a succeeding space; setting a correction amount for adjusting the position of the start edge and the end edge of a recording pulse based on an evaluation index of a decoding result, which is a result of decoding a reproduction signal of the encoded data, for each of the classification; and generating the recording pulse corresponding to the encoded data by using the correction amount corresponding to the classification of the run length of the encoded data.

A mark corresponding to recording data is formed on an optical disk by: encoding the recording data in accordance with a modulation code and generating encoded data; classifying the encoded data by a combination of at least two of a mark length of a mark, a space length of a preceding space, the mark length of a preceding mark, and the space length of a succeeding space; setting a correction amount for adjusting the position of the start edge and the end edge of a recording pulse based on an evaluation index of a decoding result, which is a result of decoding a reproduction signal of the encoded data, for each of the classification; and generating the recording pulse corresponding to the encoded data by using the correction amount corresponding to the classification of the run length of the encoded data.

A mark corresponding to recording data is formed on an optical disk by: encoding the recording data in accordance with a modulation code and generating encoded data; classifying the encoded data by a combination of at least two of a mark length of a mark, a space length of a preceding space, the mark length of a preceding mark, and the space length of a succeeding space; setting a correction amount for adjusting the position of the start edge and the end edge of a recording pulse based on an evaluation index of a decoding result, which is a result of decoding a reproduction signal of the encoded data, for each of the classification; and generating the recording pulse corresponding to the encoded data by using the correction amount corresponding to the classification of the run length of the encoded data.

Subject-matter is that between an inner edge and an outer edge of a lead-in area, are created by mechanical means grooves in the form of concentric circles around the central axis with the profile of the letter V in the protective layer, wherein these grooves have peaks and edges are created in such a way that the groove with the largest possible diameter of the circle does not exceed the inner part of the outer edge and the groove with the smallest possible diameter of the circle does not exceed the inner edge of the lead-in area, wherein the density of the grooves is such that edges of the grooves are touching each other on the surface of the protective layer and between the individual edges of the grooves there is no area undamaged by the grooves. Non-standard audio discs and video discs are manufactured by pressing from the matrix, they contain lead-in area data area and lead-out area and in the area with the radius from 18.00+1 mm to 23.50+1 mm are provided with the zone of the mechanical protection, which contains a set of grooves in the form of concentric circles, with the profile of the letter V, which are arranged closely to each other in such a way, that their upper edges are touching.

A reading method for reading contents information with a laser from an optical disc including a plurality of recording layers includes positioning a focus position of the laser at a first recording layer and reading a first part of the contents information recorded in the first recording layer. If a first link information recorded in the first recording layer is detected, judging whether a first condition is fulfilled or not. If the first condition is fulfilled, positioning the focus position of the laser at a second recording layer and reading a first link destination information recorded in the second recording layer. If the first condition is not fulfilled, reading a second part of the contents information recorded in the first recording layer.

Subject-matter is that between an inner edge and an outer edge of a lead-in area, are created by mechanical means grooves in the form of concentric circles around the central axis with the profile of the letter V in the protective layer, wherein these grooves have peaks and edges are created in such a way that the groove with the largest possible diameter of the circle does not exceed the inner part of the outer edge and the groove with the smallest possible diameter of the circle does not exceed the inner edge of the lead-in area, wherein the density of the grooves is such that edges of the grooves are touching each other on the surface of the protective layer and between the individual edges of the grooves there is no area undamaged by the grooves. Non-standard audio discs and video discs are manufactured by pressing from the matrix, they contain lead-in area data area and lead-out area and in the area with the radius from 18.00+1 mm to 23.50+1 mm are provided with the zone of the mechanical protection, which contains a set of grooves in the form of concentric circles, with the profile of the letter V, which are arranged closely to each other in such a way, that their upper edges are touching.

A reading method for reading contents information with a laser from an optical disc including a plurality of recording layers includes positioning a focus position of the laser at a first recording layer and reading a first part of the contents information recorded in the first recording layer. If a first link information recorded in the first recording layer is detected, judging whether a first condition is fulfilled or not. If the first condition is fulfilled, positioning the focus position of the laser at a second recording layer and reading a first link destination information recorded in the second recording layer. If the first condition is not fulfilled, reading a second part of the contents information recorded in the first recording layer.

There is provided an optical medium reproducing device configured to optically reproduce an optical medium including a plurality of tracks formed, the optical medium reproducing device including: an optical filter configured to receive an incident returned light beam from the optical medium, and to spatially and optically form a plurality of signals having different bands in a tangential direction and a radial direction; an arithmetic unit configured to operate the plurality of first signals formed by the optical filter so as to form a plurality of channels of second signals; and an electrical filter configured to individually receive the second signals, and to perform processing to the second signals so as to acquire a reproduced signal.