Abstract: An optical disc is includes a recording layer, a reflective layer, and a protective layer provided, in that order, on one surface of a light-transmissive substrate and a hard coating layer having a thickness in the range of 1 to 5 ?m on the other surface of the substrate. The hard coating layer is formed by applying and curing a solution comprising a hard coating agent containing colloidal silica and a UV-curable acrylic resin and a solvent containing propylene glycol monomethyl ether acetate as a principal constituent. The hard coating layer contains 110 mg/cm3 or less of residual solvent.

Abstract: An optical disc is includes a recording layer, a reflective layer, and a protective layer provided, in that order, on one surface of a light-transmissive substrate and a hard coating layer having a thickness in the range of 1 to 5 ?m on the other surface of the substrate. The hard coating layer is formed by applying and curing a solution comprising a hard coating agent containing colloidal silica and a UV-curable acrylic resin and a solvent containing propylene glycol monomethyl ether as a principal constituent. The hard coating layer contains 40 mg/cm3 or less of residual solvent.

Abstract: An optical recording medium that is constituted so that a laser beam is irradiated to record and reproduce data, the optical recording medium including a laminated body that is formed by sandwiching a second dielectric layer 6 between a recording layer 7 and a light absorption layer 5, the light absorption layer 5 containing “Ge”, “Sb and Ge”, “Sb and In”, or “Sb and Ga” as a main component.

Abstract: A reproduction apparatus is capable of reproducing information recorded on information recording media including at least a super RENS recording medium. The reproduction apparatus includes: an optical head that receives laser light that has been reflected or transmitted by the information recording medium and photoelectrically converts the laser light to an electric signal; a signal processing circuit that extracts an AC component from the electric signal and attenuates the AC component by a predetermined attenuation; an amplitude controlling circuit that controls an amplitude of an electric signal outputted from the signal processing circuit so as to become a predetermined amplitude; and a reproduction circuit that reproduces information recorded on the medium based on an electric signal outputted from the amplitude controlling circuit. An information recording medium testing apparatus includes the reproduction apparatus and a test information generating circuit that generates test information.

Abstract: An optical recording medium for recording data by irradiating a laser beam and forming a recording mark row containing at least one of recording marks and blank areas smaller than a resolution limit and reproducing the recorded data, comprising a layered body having a recording layer, a light absorbing layer, and a dielectric layer at intermediary of the recording layer and the light absorbing layer, wherein the light absorbing layer is crystalline when film formation is completed, and has a property to maintain the crystalline even when the laser beam is irradiated.

Abstract: An optical recording disc is constituted by laminating a substrate, a reflective layer, a third dielectric layer, a light absorption layer, a second dielectric layer, a metal recording layer, a first dielectric layer and a light transmission layer in this order, and is constituted so that when a laser beam is irradiated onto the optical recording disc from the side of the light transmission layer, the metal recording layer is deformed and/or is changed in quality to form a state-changed region in the metal recording layer and the second dielectric layer and the light absorption layer are deformed and/or are changed in quality to form state-changed regions in the second dielectric layer and the light absorption layer, whereby a recording mark is formed in the metal recording layer, the second dielectric layer and the light absorption layer.

Abstract: An optical recording disk includes at least a recording layer containing an organic compound containing a porphyrin system dye as a primary component and a light transmission layer which transmits a laser beam having a wavelength of 390 to 420 nm on a support substrate in this order, the porphyrin system dye having a minimal value nmin of a refractive index n within a wavelength region of 390 nm to 420 nm and a refractive index n equal to or lower than 1.2 with respect to the laser beam having the wavelength of 390 to 420 nm and absorbing the laser beam having the wavelength of 390 to 420 nm to be melted or decomposed, whereby the refractive index thereof changes and data are recorded in the optical recording disk. According to the thus constituted optical recording disk, it is possible to record data therein using a bluish-violet laser beam having a wavelength of 390 to 420 nm and reproduce data therefrom using a bluish-violet laser beam having a wavelength of 390 to 420 nm.

Abstract: A method for reproducing data according to the present invention is adapted for reproducing data recorded in an optical recording disc including a multi-layered body formed by forming a decomposition reaction layer containing noble metal oxide as a primary component and a light absorption layer so as to sandwich a dielectric layer therebetween by irradiating a laser beam onto the optical recording disc and forming a recording mark train including at least one of a recording mark having a length shorter than a resolution limit and a blank region having a length shorter than the resolution limit therein, and is constituted by changing the read power Pr of the laser beam in accordance with a readout linear velocity at which data are to be reproduced from the optical recording disc.

Abstract: A method for determining a read power of a laser beam according to the present invention includes a step of setting a power of a laser beam to a recommended recording power Pw? and forming a recording mark train including at least one of a recording mark having a length shorter than a resolution limit and a blank region having a length shorter than the resolution limit in an optical recording disc, thereby recording test data therein, a step of setting the power of the laser beam to a recommended read power Pr? and reproducing the test data recorded in the optical recording disc, a step of judging whether or not signal characteristics of a reproduced signal obtained by reproducing the test data satisfies reference conditions, and determining an optimum read power of the laser beam based on the result of the judgment.

Abstract: An optical recording medium can be recorded at a high linear velocity of at least 10 m/s while maintaining an excellent light stability and favorable reflectance. A recording medium is constructed of a recording layer on a substrate, the recording layer including a first dye with a maximum absorption wavelength in a thin-film state of 450 nm to 620 nm inclusive as a first dye and being formed so as to include a second dye with an extinction coefficient of at least 0.5 for a recording wavelength. In this case, it is preferable for the second dye to have a maximum absorption wavelength of 620 nm to 750 nm inclusive in a thin-film state.

Abstract: A laser beam is directed to an optical recording medium such as a DVD-R to successively form thereon marks of a length corresponding to data with a spacing disposed therebetween. A Q value or the amount of reduction in time causes the rise time of laser irradiation to be delayed with respect to the scheduled rise time at least after a spacing equal in length to the mark of the shortest length employed for recording. The Q value satisfies the following equation (1) expressed in terms of the relationship between the recording speed n and an asymmetry. That is, (0.54×Asymmetry?1.1)/n?Q?(0.54×Asymmetry?0.1)/n??(1) where the asymmetry is the ratio of an amplitude of the shortest mark to that of the longest mark of the recorded marks.

Abstract: It is an object of the present invention to provide a multilevel optical recording medium in which influence of variation in characteristics of a recording layer in a plane of the recording layer on reproduced data can be corrected. The multilevel optical recording medium according to the present invention includes at least a recording layer 12 and is constituted so that data can be recorded therein in a multilevel manner by controlling a state of the recording layer 12 among multiple stages and the multilevel optical recording medium according to the present invention is characterized in that a plurality of calibration signals are stored in the recording layer 12.

Abstract: A reproduction method for a multi-level optical recording medium according to the present invention rotates an optical recording medium, on which recording data has been recorded according to a multi-level recording method which sets several levels for light reflectivity of virtual recording cells, emits a reproduction laser beam towards the optical recording medium, and reproduces the recording data based on an electric signal generated in accordance with a received level of reflected light, the method setting the emission power of the reproduction laser beam in a range of 1.0 mW to 2.5 mW inclusive when the optical recording medium is rotated at a linear velocity in a range of 9 m/s to 25 m/s inclusive. By doing so, it is possible to improve the read accuracy for recording data while suppressing the reproduction deterioration of the optical recording medium to a level where deterioration effectively does not occur.

Abstract: An optical recording medium includes a support substrate, a light transmission layer and a recording layer located between the support substrate and the light transmission layer and containing an organic dye as a primary component, the light transmission layer including a first light transmission film located on the side of the recording layer and having Vickers hardness of 30 mgf/&mgr;m2 to 50 mgf/&mgr;m2 with respect to a load of 200 mgf and a second light transmission film located on the side of a light incidence plane through which a laser beam enters.

Abstract: An optical disc is includes a recording layer, a reflective layer, and a protective layer provided, in that order, on one surface of a light-transmissive substrate and a hard coating layer having a thickness in the range of 1 to 5 &mgr;m on the other surface of the substrate. The hard coating layer is formed by applying and curing a solution comprising a hard coating agent containing colloidal silica and a UV-curable acrylic resin and a solvent containing propylene glycol monomethyl ether acetate as a principal constituent. The hard coating layer contains 110 mg/cm3 or less of residual solvent.

Abstract: An optical disc is includes a recording layer, a reflective layer, and a protective layer provided, in that order, on one surface of a light-transmissive substrate and a hard coating layer having a thickness in the range of 1 to 5 &mgr;m on the other surface of the substrate. The hard coating layer is formed by applying and curing a solution comprising a hard coating agent containing colloidal silica and a UV-curable acrylic resin and a solvent containing propylene glycol monomethyl ether as a principal constituent. The hard coating layer contains 40 mg/cm3 or less of residual solvent.

Abstract: An optical disc is includes a recording layer, a reflective layer, and a protective layer provided, in that order, on one surface of a light-transmissive substrate and a hard coating layer having a thickness in the range of 1 to 5 &mgr;m on the other surface of the substrate. The hard coating layer is formed by applying and curing a solution comprising a hard coating agent containing colloidal silica and a UV-curable acrylic resin and a solvent containing butyl acetate as a principal constituent. The hard coating layer contains 90 mg/cm3 or less of residual solvent.

Abstract: An optical recording disk includes at least a recording layer containing an organic compound containing a porphyrin system dye as a primary component and a light transmission layer which transmits a laser beam having a wavelength of 390 to 420 nm on a support substrate in this order, the porphyrin system dye having a minimal value nmin of a refractive index n within a wavelength region of 390 nm to 420 nm and a refractive index n equal to or lower than 1.2 with respect to the laser beam having the wavelength of 390 to 420 nm and absorbing the laser beam having the wavelength of 390 to 420 nm to be melted or decomposed, whereby the refractive index thereof changes and data are recorded in the optical recording disk.

Abstract: A data recording method of modulating the power of a laser beam in accordance with a pulse pattern, projecting the laser beam onto a write-once type optical recording medium to form a record mark and recording data in the write-once type optical recording medium, wherein the pulse pattern is constituted by a pattern in which the power of the laser beam is set to a recording power Pw within a first period and a second period and the power of the laser beam is set to an intermediate power Pm lower than the recording power Pw within a third period provided between the first period and the second period, the length of the first period and the levels of the recording power Pw and the intermediate power Pw being set to satisfy 1.7T≦ttop2 and 1.4≦Pw/Pm where T is a length corresponding to one cycle of a reference pulse and ttop2 is the length of the first period.

Abstract: The present invention provides an optical recording medium that includes a recording layer composed mainly of an organic compound and can utilize blue-violet semiconductor laser light (390 to 420 nm in wavelength) as recording/reproducing laser light. The present invention also provides an optical recording/reproducing method using the optical recording medium. The optical recording medium 1 comprises at least a supporting substrate 2; a recording layer 3 on the supporting substrate 2, the recording layer 3 containing an organic compound as a major component; and a light-transmitting layer 5 on the recording layer 3, the light-transmitting layer 5 being capable of transmitting laser light with a wavelength of 390 to 420 nm for recording and reproducing information.