Abstract: Provided is a method of producing an optical disc recording medium with which an inexpensive optical disc recording medium can be produced. For this purpose, the method of producing an optical disc recording medium of the present invention includes the steps of preparing a transfer substrate; forming an ultraviolet-curable resin layer on a surface of the transfer substrate; forming a projection-and-recess pattern on the ultraviolet-curable resin layer by pressing a nickel stamper having a desired projection-and-recess pattern onto the ultraviolet-curable resin layer under pressure while performing ultraviolet irradiation from the reverse surface side of the transfer substrate, and forming a recording layer on the ultraviolet-curable resin layer on which the projection-and-recess pattern is formed, wherein recording layers are formed in descending order of the light transmittance.

Abstract: An optical information recording medium includes a read-only information recording portion, and a BCA (Burst Cutting Area) portion formed by laser marking. A reflective film on an information recording surface of the read-only information recording portion and a reflective film on the BCA portion are formed of the same material. The reflective film includes Ag as a main component, and at least one of Nd and Gd, and at least one of Sn and In as components; the reflective film including at least one of Nd and Gd of 0.1 atom % or more and 3.0 atom % or less in total and at least one of Sn and In of 3 atom % or more and 12 atom % or less in total. Recorded information is reproduced from the information recording surface of the read-only information recording portion and a BCA signal is reproduced from the BCA portion, using blue-violet laser reproducing light.

Abstract: The invention relates to an Ag alloy reflective film for an optical information recording medium, including Ag as a main component, at least one kind of Nd, Gd, Y and Sm in a total amount of more than 0.1 atomic percent and not more than 3.0 atomic percent and at least one kind of W, Mo, V, Zr, Nb and Cr in a total amount of 3.0 to 10.0 atomic percent; an Ag alloy reflective film for an optical information recording medium, including Ag as a main component, at least one kind of Nd, Gd, Y and Sm in a total amount of more than 0.1 atomic percent and not more than 3.0 atomic percent and at least one kind of Ti and Ta in a total amount of 5.0 to 10.0 atomic percent; an optical information recording medium including the Ag alloy reflective film; and an Ag alloy sputtering target having a composition same as that of the Ag alloy reflective film.

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: An information signal area on an information signal recording surface is provided as pits on a mirror in accordance with modulated information data, and is covered with a metal alloy reflective film. Sections that do not include pits corresponding to the information data are provided in the information signal area, and portions of the metal alloy reflective film on the sections are formed as perforated marks corresponding to the information data. In this case, the reproduction signal amplification level of a prepit signal and the reproduction signal amplitude level of a perforated mark signal can be obtained as substantially equal values by adjusting the depth and width of pits and/or adjusting the width and length of perforated marks. Hence, waveform distortion due to a waveform equalization circuit and variations in binary signals due to displacement of the slice level are reduced so that signals can be stably and reliably detected with the same reading apparatus.

Abstract: The invention provides an optical information recording medium which is compatible with Blu-ray for recording a BCA signal by laser marking, in which the optical information recording medium has superior reading properties and is improved in recording properties and reliability in a BCA portion. A reflective film 7 includes Ag as a main component, and Nd, Gd, and Bi, in which Nd, Gd and Bi are effective for long-tem storage stability and inhibition of corrosion, and an addition of a small amount of Gd is effective for enhancing absorption of laser marking light. Accordingly, the invention can provide a highly-reliable optical information recording medium that exhibits a superior reading property of an information recording portion and a BCA portion, and that simultaneously exhibits a superior recording property of the BCA portion by selection of the composition at recording a BCA signal by laser marking.

Abstract: An optical disc recording medium includes a disc substrate, at least one recording layer which is disposed on one surface side of the disc substrate, a cover layer which is disposed on a laser incident surface side of the recording layer and which is composed of a light-transmissive resin layer, and a hard coat layer which is disposed for surface protection on a laser incident surface side of the cover layer and which is composed of a light-transmissive resin layer. The cover layer is formed such that its thickness decreases from the central portion to the peripheral portion of the disc, the hard coat layer is formed such that its thickness increases from the central portion to the peripheral portion, and the total thickness of the cover layer and the hard coat layer is substantially uniform from the central portion to the peripheral portion.

Abstract: An optical disc medium 10 having a wobbled track groove 12 includes three wobble patterns including a flat wobble pattern, a positive pulse wobble pattern, and a negative pulse wobble pattern. In the flat wobble pattern, the amplitude of the wobble from the lengthwise direction of the track groove is zero such that the track groove is flat. In the positive pulse wobble pattern, the amplitude of the wobble from the lengthwise direction of the track groove is positive such that the track groove is wobbled in a first direction perpendicular to the lengthwise direction. Further, in the negative pulse wobble pattern, the amplitude of the wobble from the lengthwise direction of the track groove is negative such that the track groove is wobbled in a second direction opposite to the first direction. Then, three data values can be recorded using three distinctive wobble patterns.

Abstract: An optical-disc manufacturing method including the steps of: fabricating a pre-exposure disc master by forming, on a substrate, a heat accumulation layer having a thickness of 17% or less of a recording-laser wavelength and forming an inorganic resist layer; performing exposure of a recording-signal pattern having pits and spaces with respect to the inorganic resist layer of the disc master, by performing recording-laser light irradiation; fabricating a disc master having a pit-array shape having pits and spaces, by performing development processing after the exposure; manufacturing a stamper to which the pit-array shape is transferred, by using the disc master having the pit-array shape; and manufacturing an optical disc having a predetermined layer structure including a recording layer to which the pit-array shape of the stamper is transferred and in which a silver or silver-alloy reflective film is formed on the pit-array shape.

Abstract: A pirated optical recording medium may be determined which is produced by physically transferring a shape of pits and lands formed on a substrate of an optical recording medium. The optical recording medium is provided with excellent weatherability and long-term storage reliability. A reflective film formed of an Ag alloy film of Ag100-x-yXxCuy, where X is at least one element among Ti, W, Ta, V, Mo, Nb and Zr, is formed on a substrate on which main data is recorded with a combination of pits and lands. A mark may be formed so that a reproduction signal level in the recorded mark of auxiliary data write once recorded on the reflective film is increased, and a reproduction signal level is decreased in an optical recording medium prepared by physically transferring the surface shape of the pits and lands of the substrate. A pirated optical recording medium may be determined in this manner.

Abstract: In an optical recording and reproducing medium having a groove 2 formed along a recording track and which is recorded and/or reproduced with irradiation of light L having a predetermined wavelength ?, a track pitch p of the groove 2 is selected in a range of from 200 nm to 350 nm and a ratio wg?/p between a width wg of the groove 2 and the track pitch p is selected in a range of from 0.24 to 0.67.

Abstract: An optical recording medium wherein characters can be easily recognized on an optical disk irradiated with a light through a light transmitting layer and a method of producing the same are provided. In an optical disk of a type that an optical recording layer is irradiated with a light through a light transmitting protective layer, dealing with a larger capacity, wherein one main surface of a medium substrate 15 is divided to a signal portion SG and a character portion CA, a signal portion uneven shape (15p) is formed on the signal portion SG and a character portion uneven shape (15p) is formed on the character portion CA, and depths of the signal portion uneven shape and the character portion uneven shape are 25 nm or less. Here, it is configured that characters are recorded to be able to be read as normal characters when looking from the medium substrate 15 side (Y-direction) by outlines of a region formed with the character portion uneven shape on the character portion CA.

Abstract: An arm direction changeover valve (11) is provided in an arm block (20). A first pilot check valve (18) is provided in a first block (21). A second pilot check valve (19) is provided in a second block (22). The three blocks, i.e., the arm block (20), the first block (21), and the second block (22) are arranged side by side. The first block (21) and the second block (22) are arranged to be contiguous to each other. Accordingly, an increase in size can be prevented even if a float mechanism and a multi-direction changeover valve are formed integrally with each other.

Abstract: An optical recording/reproducing medium having grooves formed along recording tracks and used for recording/reproducing when irradiated with light L with a specified wavelength ?, wherein the track pitch p of a groove is at least 200 nm and up to 350 nm, and a ratio wg?/p between the width wg of a groove and a track pitch p is at least 0.24 and up to 0.67.

Abstract: An optical disk read only memory having an information recording surface with a concave-convex pattern formed on the basis of a first signal and a reflective film covering the surface. The disc medium includes: an additional information recording section formed on a recording track of a first data string; and a second data string including a mark of removing or reducing the reflective film. The modulation methods of the first and the second data strings are identical, and Lh(n)>Lp1(n) and Wh(n)>(Wp1(n)+Wp2(n))/2 are satisfied, where a reference clock cycle is T, a data length is nT, a length and a width of the mark are Lh(n) and Wh(n), a length and a width of a base of the pit are Lp1(n), and Wp1(n), a length and a width of a top face of the pit is Lp2(n) exceeding Lp1(n), and Wp2(n) exceeding Wp1(n).

Abstract: An optical recording medium wherein characters can be easily recognized on an optical disk irradiated with a light through a light transmitting layer and a method of producing the same are provided. In an optical disk of a type that an optical recording layer is irradiated with a light through a light transmitting protective layer, dealing with a larger capacity, wherein one main surface of a medium substrate 15 is divided to a signal portion SG and a character portion CA, a signal portion uneven shape (15p) is formed on the signal portion SG and a character portion uneven shape (15p) is formed on the character portion CA, and depths of the signal portion uneven shape and the character portion uneven shape are 25 nm or less. Here, it is configured that characters are recorded to be able to be read as normal characters when looking from the medium substrate 15 side (Y-direction) by outlines of a region formed with the character portion uneven shape on the character portion CA.

Abstract: At the stage where disc substrates are to be manufactured in mass production by using a stamper, a section where pits/lands are not formed is formed in advance as an additional information recording section among recording tracks formed by a recording data sequence of pits/lands. A metal alloy reflection film is coated on the information recording surface including such an additional information recording section 10. Then, thereafter, additional information is recorded in the additional information recording section 10 by forming hole marks 6 by erasing or decreasing a partial area of the metal alloy reflection film. The additional information is recorded in a partial area of recording tracks in the information recording area (the area where information is recorded by a recording data sequence of pits/lands, the area including a content area and a management area such as a lead-in).

Abstract: An optical recording medium using Sn as the recording material to improve the jitter is provided, in which on the surface of a disc substrate 11 where a concave and convex shape dividing a track area is formed, are formed on the surface of the concave and convex shape a first protective layer 31 for protecting at least an optical recording layer 31, an optical recording layer 12 using a chemical compound at least composed of tin (Sn), nitrogen (N) and oxygen (O), formed on the first protective layer, a second protective layer 32 for protecting this optical recording layer, formed on this optical recording layer, and a light-transmittable layer 13 formed on the second protective layer; with this structure, the optical recording layer 12 under high temperature and high humidity can be stabilized by means of the first and second protective layers 31 and 32.

Abstract: An optical information recording medium includes a read-only information recording portion, and a BCA (Burst Cutting Area) portion formed by laser marking. A reflective film on an information recording surface of the read-only information recording portion and a reflective film on the BCA portion are formed of the same material. The reflective film includes Ag as a main component, and at least one of Nd and Gd, and at least one of Sn and In as components; the reflective film including at least one of Nd and Gd of 0.1 atom % or more and 3.0 atom % or less in total and at least one of Sn and In of 3 atom % or more and 12 atom % or less in total. Recorded information is reproduced from the information recording surface of the read-only information recording portion and a BCA signal is reproduced from the BCA portion, using blue-violet laser reproducing light.

Abstract: A process, advantageous in producibility, for the production of a vinyl compound containing very small amounts of ionic impurities and hydrolysable halogens, which is capable of curing by means of heat and/or light and giving a cured product having excellent dielectric characteristics and heat resistance, which process can efficiently remove a generated salt and comprises reacting a non-protonic polar solvent solution of a specific bifunctional phenylene ether oligomer with a vinylbenzyl halide in the presence of an alkoxide of an alkali metal, wherein the thus-obtained reaction solution is acidified with a specific amount of an acidic substance, then a salt generated is removed, an alkali substance containing a specific amount of an alkali metal is added to the thus-obtained solution, then a salt generated is removed, and the thus-obtained solution is mixed with water or a water-alcohol mixed solution, to precipitate a solid.