Abstract: There is provided a method of producing a multilayer optical recording medium through which the occurrence of burrs is reduced. The method of producing a multilayer optical recording medium includes, when a UV curable adhesive is interposed between a first disk and a second disk, the first disk and the second disk are rotated, and when at least one of the vicinities of inner circumferential edges and the vicinities of outer circumferential edges of the first disk and the second disk is masked with a mask member, emitting ultraviolet rays for preliminarily curing the UV curable adhesive from the side of a light emission surface of the first disk during rotation.

Abstract: A glass blank is cut out from a glass plate by forming a crack starting portion inside the glass plate by moving a first laser beam relative to the glass plate such that a focal position of the laser beam is located in an inner portion of the glass plate in its thickness direction and the focal position forms a circle when viewed from a surface of the glass plate, then causing cracks to develop from the crack starting portion toward main surfaces of the glass plate, and splitting the glass plate to separate, from the glass plate, a glass blank that includes a separation surface having an arithmetic average surface roughness Ra smaller than 0.01 ?m and a roundness not larger than 15 ?m. Thereafter, main surfaces of the glass blank are ground or polished.

Abstract: The present disclosure relates to disk separator plates that include a coating to increase the water contact angle of the exterior surface of the disk separator plate so as to decrease its wettability. The present disclosure also involves hard disk drives that include such a disk separator plate and related methods of forming such a coating.

Abstract: A magnetic-disk substrate has an average value of squares of inclinations that is 0.0025 or less, and a frequency at which squares of inclinations are 0.004 or more is 15% or less, in a case where samples of inclinations on a main surface are obtained at intervals of 10 nm. The main surface is configured to receive at least a magnetic recording layer thereon. The magnetic-disk substrate includes an outer circumferential end portion and an inner circumferential end portion, and the outer circumferential end portion and the inner circumferential end portion have chamfered portions.

Abstract: The present invention relates to a film for blocking ultraviolet rays that has excellent light resistance, thus exhibiting stable UV blocking performance for a long time, and has a low haze value, and thus is suitable for protecting an organic light emitting device and the like from the external light source.

Abstract: Provided is a method of manufacturing a glass sheet including a step of bringing a glass sheet (G1, G2) having a first liquid adhering to a surface into contact with a roller (5a, 5b). The glass sheet (G1, G2) includes: a first glass sheet (G1); and a second glass sheet (G2) having a contact length with the roller (5a, 5b) which is larger than that of the first glass sheet (G1). The step of bringing the glass sheet (G1, G2) into contact with the roller (5a, 5b) includes a liquid supplying step of, at the time of bringing the first glass sheet (G1) into contact with the roller (5a, 5b), applying a second liquid to a non-contact portion of the roller (5a, 5b) which is prevented from being brought into contact with the first glass sheet (G1).

Abstract: A glass composition includes from 55.0 mol % to 75.0 mol % SiO2; from 8.0 mol % to 20.0 mol % Al2O3; from 3.0 mol % to 15.0 mol % Li2O; from 5.0 mol % to 15.0 mol % Na2O; and less than or equal to 1.5 mol % K2O. The glass composition has the following relationships: Al2O3+Li2O is greater than 22.5 mol %, R2O+RO is greater than or equal to 18.0 mol %, R2O/Al2O3 is greater than or equal to 1.06, SiO2+Al2O3+B2O3+P2O5 is greater than or equal to 78.0 mol %, and (SiO2+Al2O3+B2O3+P2O5)/Li2O is greater than or equal to 8.0. The glass composition may be used in a glass article or a consumer electronic product.

Abstract: A magnetic-disk substrate has a pair of main surfaces and arithmetic average roughnesses Ra of the main surfaces are each 0.11 nm or less. Also, in surface unevenness of the main surfaces, an average area of regions occupied by a plurality of protrusions having a height of 0.1 nm or more from an average plane of the surface unevenness is 25 nm2/protrusion or less. The arithmetic average roughness Ra and the surface unevenness are measured using an atomic force microscope with a probe having a probe tip provided with a carbon nanofiber rod-shaped member.

Abstract: Disclosed are a transparent thermoplastic resin composition including (A) about 5 to about 40 wt % of an impact-reinforcing agent having a core-shell structure where an acrylic-based compound is grafted on a rubber core including a copolymer of an acrylic-based monomer and a diene-based monomer, to form a shell, and (B) about 60 to about 95 wt % of an acrylic-based resin, and a molded article using the same.

Abstract: A method, system and apparatus are disclosed for forming a lubricant film for magnetic recording applications. The method includes, in certain embodiments, providing at least one substantially solvent free lubricant having a plurality of lubricant molecules with each lubricant molecule comprising a polymer chain having a backbone section and at least one functional end group. The method also includes treating the at least one substantially solvent free lubricant with a physical treatment to cross-link the backbone section of each polymer chain with at least one other molecule to create a cross-linked lubricant.

Abstract: A non-ablative method and apparatus for making an economical glass hard disk (platter) for a computer hard disk drive (HDD) using a material machining technique involving filamentation by burst ultrafast laser pulses. Two related methods disclosed, differing only in whether the glass substrate the HDD platter is to be cut from has been coated with all the necessary material layers to function as a magnetic media in a computer's hard drive. Platter blanks are precisely cut using filamentation by burst ultrafast laser pulses such that the blank's edges need not be ground, the platter's geometric circularity need not be corrected and there is no need for further surface polishing. Thus the platters can be cut from raw glass or coated glass. As a result, this method reduces the product contamination, speeds up production, and realizes great reductions in the quantity of waste materials and lower production costs.

Abstract: A magnetic disk substrate highly reliable to prevent the occurrence of crash failure even if a magnetic disk is rotated at high speed, and suitable for a hard disk that starts and stops by the load/unload method, and a magnetic disk using such a substrate. The representative structure of the magnetic disk substrate is a disk-shaped glass substrate 10 having a generally flat main surface 11, an end face 12, a chamfered face 13 formed between the main surface 11 and the end face 12, and an offset portion, at the periphery of the main surface 11, raised or lowered with respect to a flat surface, other than the periphery, of the main surface 11, and characterized in that the magnitude of the offset portion is approximately uniform over the entire circumference of the glass substrate 10.

Abstract: An aspect of the present invention relates to glass for a magnetic recording medium substrate, which includes essential components in the form of SiO2, Li2O, Na2O, and one or more alkaline earth metal oxides selected from the group consisting of MgO, CaO, SrO, and BaO, wherein a molar ratio of a content of MgO to a combined content of MgO, CaO, SrO, and BaO (MgO/(MgO+CaO+SrO+BaO)) is equal to or greater than 0.80, and which has a Young's modulus of equal to or greater than 80 GPa, and a glass transition temperature of equal to or greater than 620° C.

Abstract: A substrate for a magnetic recording medium having a disc shape with a central hole is provided in which the surface roughness of the principal surface of the substrate is 1 angstrom or less in terms of root mean square roughness (Rq) when a space period (L) of an undulation in the circumferential direction is in the range 10 to 1,000 ?m, and in which when a component in the vertical axis direction of a line segment Z connecting a point A with the space period (L) of 10 ?m and a point B with the space period (L) of 1,000 ?m in a curve S marked on a double logarithmic graph which is obtained by analyzing the surface roughness using a spectrum and in which the horizontal axis is set to the space period (L) (?m) and the vertical axis is set to the power spectrum density (PSD) (k·angstrom2·?m) (where k is a constant) is defined as H and a displacement at which the component in the vertical axis direction of the curve S is the maximum with respect to the line segment Z is defined as ?H, a value (P) expressed by (?

Abstract: A disk (100) having a center hole (100a), the disk (100) being provided with a support-capable structure for making it possible to support a disk (100A) positioned one level above the lowermost part in a stacked state using separation claws (164Ac, 164Bc) protruding radially outward from the center hole (100a).

Abstract: The embodiments disclose a block copolymer assembly structure, including a first pattern and second pattern with a first density of patterned features integrated in data and servo zones, a silicon substrate with thin film layers deposited thereon and patterned using the first density of first pattern and second pattern features and a template fabrication pattern with a second density greater than the first density created using ordered block copolymer periodic structures across a portion of the substrate.

Abstract: A curable composition for imprints, which is excellent in patternability and in line edge roughness, is provided. The curable composition for imprints comprises at least one kind of polymerizable monomer (A) and at least one kind of photopolymerization initiator (B). The polymerizable monomer (A) comprises at least two fluorine-containing groups selected from a fluoroalkyl group and a fluoroalkylether group and each of two of the fluorine-containing groups is connected with each other through a linking group having at least two carbon atoms.

Abstract: An aspect of the present invention relates to glass for a magnetic recording medium substrate, which includes essential components in the form of SiO2, Li2O, Na2O, and one or more alkaline earth metal oxides selected from the group consisting of MgO, CaO, SrO, and BaO, wherein a molar ratio of a content of MgO to a combined content of MgO, CaO, SrO, and BaO (MgO/(MgO+CaO+SrO+BaO)) is equal to or greater than 0.80, and which has a Young's modulus of equal to or greater than 80 GPa, and a glass transition temperature of equal to or greater than 620° C.

Abstract: Provided are a magnetic disk substrate and a method of manufacturing the same, wherein the magnetic disk substrate has very few defects present on its surface with an arithmetic mean roughness (Ra) at a level in the vicinity of 0.1 nm and thus is suitable as a substrate for a magnetic disk with high recording density. The magnetic disk glass substrate is such that the arithmetic mean roughness (Ra) of the main surface of the glass substrate measured using an atomic force microscope with a resolution of 256×256 pixels in a 2 ?m×2 ?m square is 0.12 nm or less and the number of defects detected to have a size of 0.1 ?m to 0.6 ?m in plan view and a depth of 0.5 nm to 2 nm is less than 10 per 24 cm2, wherein the defects are each detected using a shift in wavelength between incident light and reflected light upon irradiating and scanning helium neon laser light with a wavelength of 632 nm on the main surface of the glass substrate.

Abstract: A curable composition for imprints, comprising a polymerizable monomer (Ax) represented by the following formula: wherein Ar represents a divalent or trivalent aromatic group, X represents a single bond or an organic linking group, R1 represents a hydrogen atom or an alkyl group, and n represents 2 or 3. The content of the polymerizable monomer (Ax) is 45% by mass or more, or the total content of solid polymerizable monomers and liquid polymerizable monomers with high viscosity is less than 50% by mass.

Abstract: A base element for a fixing belt are provided. The base element includes a sheet which is made of a heat resistant resin and has opposite end portions joined in an endless state. A conductive film layer of a thickness of 3 to 15 ?m is provided over two third or more area of an inner surface of the endless belt.

Abstract: A curable composition for imprints, comprising at least one polymerizable monomer and a photopolymerization initiator, wherein the content of a polymerizable monomer having a viscosity at 25° C. of 7 mPa·s or more is 80% by mass or more, relative to all the polymerizable monomers contained in the composition. The curable composition for imprints has low volatility of the components even in a thin film coating on a substrate and is thus capable of forming a good pattern.

Abstract: A glass substrate for information recording medium, said glass substrate being composed of an aluminosilicate glass containing 60-75% by mass of SiO2, 5-18% by mass of Al2O3, 3-10% by mass of Li2O, 3-15% by mass of Na2O and 0.5-8% by mass of ZrO2 relative to the entire glass components. The glass substrate for information recording medium contains neither As (arsenic) nor Sb (antimony), while containing at least one polyvalent element selected from the group consisting of V (vanadium), Mn (manganese), Ni (nickel), Nb (niobium), Mo (molybdenum), Sn (tin), Ce (cerium), Ta (tantalum) and Bi (bismuth). The molar ratio of the total amount of the polyvalent elements to the amount of Al2O3 is within the range of 0.02-0.20.

Abstract: A system, method, and apparatus for forming a high quality master pattern for patterned media, including features to support servo patterns, is disclosed. Block copolymer self-assembly is used to facilitate the formation of a track pattern with narrower tracks. E-beam lithography forms a chemical contrast pattern of concentric rings, where the spacing of the rings is equal to an integral multiple of the target track pitch. The rings include regions within each servo sector header where the rings are offset radially by a fraction of a track pitch. Self-assembly is performed to form a new ring pattern at the target track pitch on top of the chemical contrast pattern, including the radial offsets in the servo sector headers. When this pattern is transferred to disks via nanoimprinting and etching, it creates tracks separated by nonmagnetic grooves, with the grooves and tracks including the radial offset regions.

Abstract: An improved patterned magnetic bit data storage media and a method for manufacturing the same is disclosed. In one particular exemplary embodiment, the improved patterned magnetic bit data storage media may comprise an active region exhibiting substantially ferromagnetism; and an inactive region exhibiting substantially paramagnetism, the inactive region comprising at least two grains and a grain boundary interposed therebetween, wherein each of the at least two grains contain ferromagnetic material, and wherein the at least two grains are antiferromagnetically coupled.

Abstract: The disclosure relates to a steam stripping process for producing purified polyimides, e.g., polyetherimide homopolymers and polyetherimide copolymers. The process can include contacting an initial polyimide with steam to remove a volatile species from the initial polyimide to produce a purified polyimide. The purified polyimide can have a weight average molecular weight of from 5,000 to 80,000 Daltons. The weight average molecular weight of the purified polyimide can be greater than or equal to 90% of the weight average molecular weight of the initial polyimide. The purified polyimide can have less than 44 ppm of a volatile species, having a molecular weight of less than 250 Daltons. The polyimide can have less than 10 ppm of a metal cation.

Abstract: A method for producing a glass substrate for a magnetic disk involving the use of a polishing pad having: a first resin foam layer which forms the polishing surface, includes a resin foam having pores with a pore diameter of more than 20 ?m and has a thickness of 400 ?m or less; and a second resin foam layer which is provided between a platen for fixing the polishing pad and the first resin foam layer, includes a resin foam having pores with a pore diameter of 20 ?m or less and has a thickness of 50 to 250 ?m, and in which a total thickness of the first resin foam layer and the second resin foam layer is 550 ?m or less, and a international rubber hardness degree of the polishing pad measured by the M method according to JIS K6253 is 40 IRHD or more.

Abstract: The polyester film roll, which is free from wrinkles and slacks generated with the passage of time and is having a good roll appearance, is provided without changing the characteristics of the film.

Abstract: A glass for an information recording medium substrate, which comprises, as represented by mol % based on the following oxides, from 61 to 72% of SiO2, from 3 to 11% of Al2O3, from 0 to 14.3% of Li2O, from 0 to 22% of Na2O, from 0 to 22% of K2O, from 4 to 13% of MgO, from 0 to 6% of TiO2 and from 0 to 5% of ZrO2, provided that the total content of Li2O, Na2O and K2O (R2O) is from 10 to 22%, and (a) the ratio of the content of Li2O to R2O (Li2O/R2O) is at most 0.52, (b) the ratio of the content of Na2O to R2O (Na2O/R2O) is at least 0.35, or (c) the ratio of the content of K2O to R2O (K2O/R2O) is at least 0.45.

Abstract: According to an embodiment, a storage medium includes a transparent resin substrate having a concentric or spiral groove and a recording film formed on the groove on the transparent resin substrate, a recording mark being formed by irradiation of a laser beam, wherein a reproduction durability count in a case where reproduction is continuously carried out by a laser beam is 1,000,000 or more.

Abstract: A substrate for a recording medium suited for thermally assisted recording methods has a disc shape with a center hole and includes a silicon single-crystal supporting member; an SiO2 film formed on the silicon single-crystal supporting member; a main face having a film thickness of the SiO2 film thereon which is less than 10 nm; a substrate inner periphery end face adjacent to the center hole; a substrate inner periphery chamfer portion adjacent to the main face and to the substrate inner periphery end face; a substrate outer periphery end face positioned on the side of the main face opposite the substrate inner periphery end face; and a substrate outer periphery chamfer portion adjacent to the main face and to the substrate outer periphery end face. A magnetic recording medium includes at least the above substrate and a magnetic recording layer formed on the substrate.

Abstract: The present invention provides a multi-layered object having a hard coat layer capable of improving anti-staining property, anti-staining durability, scratch resistance, abrasion resistance and the like. A multi-layered object comprising a hard coat layer and a light transmitting layer, wherein the hard coat layer is formed from a composition for hard coat comprising: an active energy ray-curable silicone-acrylic copolymer (A); and an active energy ray-curable polyfunctional compound (B), and wherein the active energy ray-curable silicone-acrylic copolymer (A) contains: a polysiloxane block (a-1), an acrylic block (a-2) containing an active energy ray-curable double bond group and a fluoroalkyl group-containing acrylic block (a-3).

Abstract: The present invention relates to a colloidal silica slurry used in a method for manufacturing a glass substrate for an information recording medium, the method including: a lapping step of lapping a main surface of a circular glass plate; a subsequent cerium oxide polishing step of polishing the main surface of the circular glass plate with a slurry containing a cerium oxide abrasive; and a colloidal silica polishing step of polishing the main surface of the circular glass plate with a slurry containing a colloidal silica abrasive after the cerium oxide polishing step, in which the colloidal silica abrasive has a BET average particle size determined by a BET specific surface area measuring method of 40 nm or less, and a smoothness index represented by a ratio (BET average particle size (nm)/Circularity) of the BET average particle size and a circularity indicated by 4·?·S/L2 in which an area per one particle of the colloidal silica abrasive is taken as S and an outer peripheral length thereof is taken as L, o

Abstract: An electrically responsive ink composition comprising at least one electrically responsive optical-state change material, at least one electrolyte material, at least one solvent, and at least one binder material, wherein the ink composition has a viscosity between about 0.1 centipoise and about 10,000 centipoise, and a maximum optical absorbance in a range from about 200 nanometers to about 800 nanometers; and wherein the ink composition is capable of transforming from a first optical state to a second optical state upon exposure to an electrical stimulus. The electrically responsive ink composition may be used to deposit an electrically responsive coating composition, which may be used as part of an anti-theft system for optical articles. Articles comprising electrically responsive coating compositions are also disclosed, as are methods for activation.

Abstract: A method for manufacturing a glass substrate for an information recording medium, wherein the abrasive and foreign matters adhered on the glass substrate after the polishing step are surely removed without making the cleaning step complicated. The glass substrate is cleaned by scrubbing with water to which 0.5-5.0 mass % of hydrogen peroxide has been added as a cleaning solution.

Abstract: Provided are a magnetic disk substrate and a method of manufacturing the same, wherein the magnetic disk substrate has very few defects present on its surface with an arithmetic mean roughness (Ra) at a level in the vicinity of 0.1 nm and thus is suitable as a substrate for a magnetic disk with high recording density. The magnetic disk glass substrate is such that the arithmetic mean roughness (Ra) of the main surface of the glass substrate measured using an atomic force microscope with a resolution of 256×256 pixels in a 2 ?m×2 ?m square is 0.12 nm or less and the number of defects detected to have a size of 0.1 ?m to 0.6 ?m in plan view and a depth of 0.5 nm to 2 nm is less than 10 per 24 cm2, wherein the defects are each detected using a shift in wavelength between incident light and reflected light upon irradiating and scanning helium neon laser light with a wavelength of 632 nm on the main surface of the glass substrate.

Abstract: Disclosed is a digital information media having an adhesion promotion layer supported on a dummy (L1) substrate that enables secure bonding of the L1 layer, directly or indirectly, to the rest of the stack of layers in the digital information media. Certain materials including metals, metal alloys, or metalloids enhance adhesion between the adhesive layer and the L1. By applying an adhesion promotion layer of such materials on an inner surface of the L1, the bond between the adhesive and the adhesion promotion layer improves bonding and reduces a tendency for the L1 to delaminate from the rest of the stack. The tendency for breakage of the media at the juncture between the adhesion promotion layer and the adhesive is reduced, and incursion of moisture or oxygen through the interface between the adhesion promotion layer and the adhesive is inhibited.

Abstract: In an information recording apparatus such as a hard disk drive, a ramp for retreating its head from a recording medium when the apparatus is stopped is provided opposing the information recording medium. In such an information recording apparatus, the information recording medium may sometimes collide with the ramp when the apparatus falls down. By inclining a portion opposing the ramp of a glass substrate in the information recording medium, even if the information recording medium strikes the ramp, the information recording medium is prevented from being cracked.

Abstract: An improved patterned magnetic bit data storage media and a method for manufacturing the same is disclosed. In one particular exemplary embodiment, the improved patterned magnetic bit data storage media may comprise an active region exhibiting substantially ferromagnetism; and an inactive region exhibiting substantially paramagnetism, the inactive region comprising at least two grains and a grain boundary interposed therebetween, wherein each of the at least two grains contain ferromagnetic material, and wherein the at least two grains are antiferromagnetically coupled.

Abstract: A glass substrate for information recording medium, said glass substrate being composed of an alminosilicate glass containing 60-75% by mass of SiO2, 5-18% by mass of Al2O3, 3-10% by mass of Li2O, 3-15% by mass of Na2O and 0.5-8% by mass of ZrO2 relative to the entire glass components. The glass substrate for information recording medium contains neither As (arsenic) nor Sb (antimony), while containing at least one polyvalent element selected from the group consisting of V (vanadium), Mn (manganese), Ni (nickel), Nb (niobium), Mo (molybdenum), Sn (tin), Ce (cerium), Ta (tantalum) and Bi (bismuth). The molar ratio of the total amount of the polyvalent elements to the amount of ZrO2 is within the range of 0.05-0.50.

Abstract: A glass substrate for information recording medium, said glass substrate being composed of an alminosilicate glass containing 60-75% by mass of SiO2, 5-18% by mass of Al2O3, 3-10% by mass of Li2O, 3-15% by mass of Na2O and 0.5-8% by mass of ZrO2 relative to the entire glass components. The glass substrate for information recording medium contains neither As (arsenic) nor Sb (antimony), while containing at least one substance selected from the group consisting of SO3 (sulfurous acid), F (fluorine), Cl (chlorine), Br (bromine) and I (iodine), as a refining agent. The molar ratio of the total amount of the refining agent to the amount of ZrO2 is within the range of 0.05-0.50.

Abstract: A method for forming a glass substrate comprises the steps of forming a glass blank with opposing substantially planar surfaces and at least one edge, coating the glass blank in silica-alumina nanoparticles, the silica-alumina nanoparticles comprising an inner core of silica with an outer shell of alumina, annealing the coated glass blank to form a conformal coating of silica-alumina around the glass blank, and polishing the coated glass blank to remove the conformal coating of silica-alumina from the opposing substantially planar surfaces thereof.

Abstract: An apparatus includes a substrate, a magnetically soft underlayer on the substrate, and a plurality of generally cubic FePt nanoparticles on the magnetically soft underlayer, wherein the nanoparticles have a magnetization in a direction substantially normal to a surface of the magnetically soft underlayer. The FePt nanoparticles can have magnetically easy axes perpendicular to the surface of the soft underlayer.

Abstract: An information recording medium comprises a substrate, a second recording layer, a second light transmitting layer, a first recording layer for recording different information from that to be recorded in the second recording layer, and a first light transmitting layer. The second recording layer is formed with a continuous second microscopic pattern of grooves. The first recording layer is formed with a continuous first microscopic pattern of grooves that is different from the second microscopic pattern. Both sidewalls of raised portions of the first and second microscopic patterns are formed with wobbling so as to be parallel with each other. Auxiliary information and a reference clock is recorded on these sidewalls alternately and continuously.

Abstract: If an ultraviolet curing resin is colored by contamination by another substance, there have been issues regarding increased cost and the environmental burden of treating the waste solution due to an inability to recycle the resin as it is. The ultraviolet curing resin that is in a colored, uncured state is decolored in the present invention by irradiation of light having a wavelength in the vicinity of the maximum absorption wavelength of the coloring material, and then recycled. As a result, it is possible to reduce costs and contribute to the protection of the environment.

Abstract: An optical disc of a desired thickness is formed by adhering a stamper substrate 20 to an L0 layer substrate 10. Concave/convex portions to transfer fine concave/convex portions for an L1 layer are formed on one principal plane of the stamper substrate 20. After the fine concave/convex portions for the L1 layer were transferred and formed onto an intermediate layer 32 by the stamper substrate 20, the stamper substrate 20 is adhered to the L0 layer substrate 10.

Abstract: A liquid precursor for a gel comprises liquid polyethylene glycol (PEG), a gelling component such as a mixture of acrylic derivatives and optionally a polymerization initiator. A suitable polymerization initiator is the photoinitiator diphenyl-(2,4,6-trimethylbenzoyl)phosphine oxide. Gelation may be achieved by irradiation with UV. The resulting gel may be free from water and exhibits high viscosity over a wide range of operating conditions. The gel is suitable for use in an indication device suitable for indicating exposure to an accelerating force above a desired threshold. The indication device may be used to indicate whether an information carrier (such as a computer-readable optical disc) has previously been accessed.

Abstract: An information recording medium comprises a substrate, a second recording layer, a second light transmitting layer, a first recording layer for recording different information from that to be recorded in the second recording layer, and a first light transmitting layer. The second recording layer is formed with a continuous second microscopic pattern of grooves. The first recording layer is formed with a continuous first microscopic pattern of grooves that is different from the second microscopic pattern. Both sidewalls of raised portions of the first and second microscopic patterns are formed with wobbling so as to be parallel with each other. Auxiliary information and a reference clock is recorded on these sidewalls alternately and continuously.

Abstract: An information recording medium comprises a substrate, a second recording layer, a second light transmitting layer, a first recording layer for recording different information from that to be recorded in the second recording layer, and a first light transmitting layer. The second recording layer is formed with a continuous second microscopic pattern of grooves. The first recording layer is formed with a continuous first microscopic pattern of grooves that is different from the second microscopic pattern. Both sidewalls of raised portions of the first and second microscopic patterns are formed with wobbling so as to be parallel with each other. Auxiliary information and a reference clock is recorded on these sidewalls alternately and continuously.

Abstract: An information recording medium comprises a substrate, a second recording layer, a second light transmitting layer, a first recording layer for recording different information from that to be recorded in the second recording layer, and a first light transmitting layer. The second recording layer is formed with a continuous second microscopic pattern of grooves. The first recording layer is formed with a continuous first microscopic pattern of grooves that is different from the second microscopic pattern. Both sidewalls of raised portions of the first and second microscopic patterns are formed with wobbling so as to be parallel with each other. Auxiliary information and a reference clock is recorded on these sidewalls alternately and continuously.