Abstract: A method for setting recording power of recording light, capable of an appropriate setting for a multilayer optical recording medium. The recording power of the recording light for an information recording layer of the multilayer optical recording medium to be irradiated with, is set by: evaluating an information recording layer to be evaluated for recording power when all the information recording layer(s) lying closer to a light incident surface than the information recording layer to be evaluated does is/are in a low transmittance state; evaluating the information recording layer to be evaluated for recording power when all the information recording layer(s) lying closer to the light incident surface than the information recording layer to be evaluated does is/are in a high transmittance state; and determining ground information for setting recording power, based on these values of the recording power.

Abstract: A multilayer optical recording medium having three or more information recording layers is irradiated with a laser beam, and a first signal obtained from the reflected laser beam is subjected to a frequency filter. A second signal obtained by filtration through a high-pass filter is used to evaluate the characteristics of the multilayer optical recording medium. In this manner, even in a multilayer optical recording medium having three or more information recording layers, the influence of the variation of the thickness and material of the information recording layers and the influence of the variation of the thickness of a spacer layer can be clearly determined and evaluated.

Abstract: An optical recording medium has a five-layer structure including five recording layers, namely an L0 layer, an L1 layer, an L2 layer, an L3 layer, and an L4 layer in this order from a side farthest away from a laser light incident surface. The materials of the respective recording layers are selected so that the rate of change in transmittance Tb/Ta as taken from the laser light incident surface satisfies 0.93<Tb/Ta<1.07 when recording on the L0 layer among the recording layers, where: Ta is transmittance of laser light to reach the L0 layer when the L0 layer is irradiated with the laser light of optimum recording power after recording marks are formed on all the recording layers closer to the laser light incident surface (being the L1 to L4 layers); and Tb is transmittance of laser light to reach the L0 layer when the L0 layer is irradiated with the laser light of optimum recording power with no recording mark formed on any of the recording layers closer to the laser light incident surface.

Abstract: In a multi-layer optical disc, having three (3) or more recording layers thereof, for enabling an easy focus lead-in operation onto a desired recording layer, reflectivity of respective recording layers are so determined that a ratio between the reflectivity of the desired recording layer and the reflectivity of other recording layers is equal or greater than a predetermined value, upon basis of the reflectivity of the other recording layers.

Abstract: A method and apparatus for measuring the read stability of an optical disc are provided. Specifically, readout of the optical disc is repeated at each of at least two read laser beams powers being different from each other. A graph is drawn in which the inverses of the read powers are plotted on a horizontal axis and in which on a vertical axis is plotted the logarithm of a repeated readout number for each of the read powers. Here, the repeated readout number is the number of repetitions of the readout when a characteristic value for the number of repetitions of the readout varies and reaches a predetermined value. The read stability of the optical disc is evaluated by using the gradient of the graph.

Abstract: A method of optimizing a writing condition of an optical recording medium, including writing test pattern data with the writing condition on the optical recording medium, comparing an error pattern binary signal detected by reproducing the written test pattern data with a correct pattern binary signal of the test pattern data, and determining an optimum writing condition of the optical recording medium based on a result of the comparison.

Abstract: When there is a defect area in a specific recording layer, recording of information is continued and reduction in a recording rate is restrained. In an optical recording method for recording information on a multilayer optical recording medium having a plurality of recording layers by irradiating the recording layer with a beam spot, any recording layer is set as an escape recording layer. When a defect area is detected while information is recorded on another recording layer except for the escape recording layer, the beam spot moves to the escape recording layer to continue recording the information.

Abstract: An object of the invention is to provide an optical recording medium and a method for producing an optical recording medium that enable to improve the quality of a servo signal and a reproduction signal. The optical recording medium satisfies: t3?t4?1 ?m, t4?t2?1 ?m, t2?10 ?m, and t1?(t2+t3+t4)?1 ?m, where t1 is a thickness between a surface of the optical recording medium, and the first information recording surface, t2 is a thickness between the first optical recording surface and the second information recording surface, t3 is a thickness between the second optical recording surface and the third information recording surface, and t4 is a thickness between the third optical recording surface and the fourth information recording surface.

Abstract: A super-resolution optical recording medium has at least a recording layer and a super resolution layer on a substrate. A recording mark with the size of a resolution limit or less and a space with the size of the resolution limit or less are formed in the super-resolution optical recording medium by adjusting the intensity of a laser for recording or an emission pattern of the laser for recording such that at least the recoding mark with the size of the resolution limit or less out of recording marks in a modulation code is formed into a concave section with respect to a not-recorded section.

Abstract: A method for recording information on an optical recording medium in which a laser beam modulated into one or a plurality of write pulses with one or a plurality of write powers in accordance with target data to be written is projected onto a recording layer of the optical recording medium to form a record mark. During recording the information on the optical recording medium, a data level and a weight index are assigned to each channel bit in reference data trains before and after the target data. Recording compensation of the target data is carried out in accordance with the sum totals of the products of the data level and the weight index in the reference data trains, so that it is possible to easily carry out high a real recording by writing fine mark/space trains.

Abstract: An information recording method for a multi-layered optical recording medium that can form information recording layers in 3 layers or more. When all the information recording layers are blank, the information recording layer that is the closest to the light incident surface is irradiated with a laser beam to start recording. High quality information recording is thus implemented in consideration of adherence of foreign matters and occurrence of scratches.

Abstract: In an optical information medium having an information bearing surface having projections and depressions and/or capable of forming recorded marks, a functional layer is added. The information borne on the information bearing surface can be read by using reading light of a wavelength longer than 4NA·PL wherein PL is the minimum size of the projections and depressions or the recorded marks and NA is the numerical aperture of a reading optical system, setting the power of the reading light within such a range that the functional layer does not change its complex index of refraction, and irradiating the reading light to the information bearing surface constructed by the functional layer or to the information bearing surface through the functional layer or to the functional layer through the information bearing surface. The medium enables reading at a high resolution beyond the diffraction limit.

Abstract: A multilayer optical recording medium enabled to retain an ideal signal regenerating property in spite of accidental adhesion of finger mark or alien substance is provided. The multilayer optical recording medium 1 is provided with a plurality of information-recording layers 20, 22, 24, and 26 capable of reading information with a reading light irradiated through a light incidence surface 38A on one side and is so adapted that the light incidence side information-recording layer 26 approximating most closely to the light incidence surface 38A may be set at a small recording capacity as compared with the recording capacities of at least one of the other information-recording layers.

Abstract: An optical recording medium which includes three or more information layers and has a higher stack density of information layers than before in the direction of thickness while reducing crosstalk during reproduction, and a method for reading the optical recording medium are provided. The optical recording medium has a three-layer structure which includes a substrate, a first information layer, a first spacer layer, a second information layer, a second spacer layer, a third information layer, and a cover layer thinner than the substrate, with these layers being stacked in that order over the substrate, wherein the following Equation (I) is satisfied: (R2×R3×R2)/R1?0.0032 ??Equation (I) where R1 is the reflectivity of the first information layer, R2 is the reflectivity of the second information layer, and R3 is the reflectivity of the third information layer, and the first spacer layer and the second spacer layer are equal to each other in thickness.

Abstract: A recording method for irradiating a multi-layered optical recording medium with a laser beam to record information thereon. The optical recording medium can form a first information recording layer that is the farthest from a light incident surface, a second information recording layer that is the second farthest from the light incident surface, and at least one third information recording layer that is located closer to the light incident surface than the second information recording layer is. The method is to record information on the second information recording layer when all the information recording layers other than the second information recording layer are either blank or have been completely recorded. This allows for realizing high-quality information recording in consideration of adherence of foreign matters or occurrence of scratches.

Abstract: Information is recorded on a multi-layered optical recording medium by irradiating it with a laser beam. The recording medium can form a first information recording layer that is the farthest from a light incident surface, a second information recording layer that is the second farthest from the light incident surface, and at least one third information recording layer that is located closer to the light incident surface than the second information recording layer is. At this time, if all the information recording layers other than the first information recording layer are either blank or have been completely recorded, then information is recorded on the first information recording layer. This allows for stabilizing the energy of a recording laser beam during recording and thereby providing improved recording quality.

Abstract: A method for determining recording laser power on a super-resolution optical recording medium, on which information is recorded on a super-resolution optical recording medium by irradiating a laser beam modulated into a recording pulse train according to recording data to thereby form a recording mark train including recording marks and spaces smaller than the resolution limit of a reproduction optical system and recording marks and spaces equal to or larger than the resolution limit, is provided. At the time of recording, the method determines a minimum value and a maximum value of recordable laser powers determined by test-writing before recording, and determines a maximum value of a recordable range of laser power by adding to the minimum value one-third of a difference between the maximum value of the recordable laser powers and the minimum value. The method determines an optimal range of recording laser power from the minimum value of recordable laser powers to the maximum value of the recordable range.

Abstract: An optical recording disc includes a substrate, a third dielectric layer, a light absorption layer, a second dielectric layer, a decomposition reaction layer containing platinum oxide as a primary component, a first dielectric layer, and a light transmission layer. The decomposition reaction layer has a thickness of 2 nm to 20 nm, and the optical recording disc is constituted so that when it is irradiated with a laser beam from the side of the light transmission layer, the platinum oxide contained in the decomposition reaction layer as a primary component is decomposed into platinum and oxygen. A bubble pit is formed in the decomposition reaction layer by thus generated oxygen gas, and fine particles of the noble metal precipitate into the bubble pit, thereby forming a recording mark in the decomposition reaction layer.

Abstract: In a data recording and readingout system in which data is recorded and readout, or is readout on, or from an optical recording medium 1 by irradiating a laser beam having a wavelength “?” via an objective lens of a numerical aperture “NA” onto said optical recording medium, while the optical recording medium contains a layered structure formed by sandwiching a dielectric layer 6 between a recording layer 7 and an optical absorption layer 5, with respect to the optical recording medium 1 arranged in such a manner that data recorded by a recorded mark train can be readout and the recorded mark train contains a recorded mark smaller than, or equal to a limit of resolution, the laser beam is irradiated via the objective lens and a solid immersion lens having a refractive index “n” which is positioned between the optical recording medium and the objective lens, so that the data is recorded and readout, or is readout with respect to the optical recording medium by a recorded mark train which contains a recorded ma

Abstract: A multi-layered optical recording medium is provided of which the manufacturing costs is significantly reduced. The multi-layered optical recording medium has multiple information recording layers and at least two layers of the information recording layers have the same medium-side address information. This configuration allows for reducing the types of master stampers and thus reducing manufacturing costs.