摘要:
There are disclosed an information recording medium substrate having a surface roughness of Rmax 15 nm or less, and an information recording medium, particularly an information recording medium substrate and information recording medium in which for surfaces of the substrate and medium, a bearing area value (offset bearing area value) in a depth of 0.5 to 5 nm (predetermined slice level) from a bearing height (real peak height) corresponding to the bearing area value of 0.2% to 1.0% is 90% or less, and a manufacture method of the substrate and medium.
摘要:
There are disclosed an information recording medium substrate having a surface roughness of Rmax 15 nm or less, and an information recording medium, particularly an information recording medium substrate and information recording medium in which for surfaces of the substrate and medium, a bearing area value (offset bearing area value) in a depth of 0.5 to 5 nm (predetermined slice level) from a bearing height (real peak height) corresponding to the bearing area value of 0.2% to 1.0% is 90% or less, and a manufacture method of the substrate and medium.
摘要:
A substrate for an information recording medium, wherein the period of microwaviness is 2 &mgr;m to 4 mm, and if we let wa be the maximum height of this microwaviness and Rmax be the maximum height measured by atomic force microscope, the main surface of the substrate has a wa of no more than 5 nm and an Rmax of no more than 12 nm, provided that wa is the difference between the highest and lowest points on a measurement curve of all measured points in a measurement area.
摘要:
A substrate for an information recording medium has a microwaviness average height Ra′ not greater than 0.05 microinch as measured by a contactless laser interference technique for measurement points within a measurement region of 50 μm□-4 mm□ on a surface of the substrate. The microwaviness average height Ra′ is given by: Ra ′ = 1 n ∑ i = 1 n | xi - x _ | , where xi represents a measurement point value of each measurement point, {overscore (x)} representing an average value of the measurement point values, n representing the number of said measurement points. Alternatively, the substrate has a waviness period between 300 μm and 5 mm and a waviness average height Wa of 1.0 nm or less as measured by the contactless laser interference technique for measurement points in a measurement region surrounded by two concentric circles which is spaced from a center of a surface of the substrate by a predetermined distance. The waviness average height Wa is given by: Wa = 1 N ∑ i = 1 N | Xi - X _ | where Xi represents a measurement point value of each measurement point, {overscore (X)} representing an average value of the measurement point values, n representing the number of said measurement points.
摘要:
A magnetic recording medium that is high coersive force, hard to receive influence of thermal fluctuation, and brings about a considerable improvement of S/N ratio, and in which at least an underlayer and a magnetic layer are sequentially laminated on a substrate, wherein a pre-coat layer is interposed between said underlayer and said substrate and said pre-coat layer is constructed by sequentially laminating a lower layer containing Ni and P and an upper layer made of a Cr alloy.
摘要:
A substrate for an information recording medium has a microwaviness average height Ra′ not greater than 0.05 microinch as measured by a contactless laser interference technique for measurement points within a measurement region of 50 &mgr;m□-4 mm□ on a surface of the substrate. The microwaviness average height Ra′ is given by: Ra ′ = 1 n ∑ i = 1 n &LeftBracketingBar; x i - x _ &RightBracketingBar; , where xi represents a measurement point value of each measurement point, {overscore (x)} representing an average value of the measurement point values, n representing the number of said measurement points. Alternatively, the substrate has a waviness period between 300 &mgr;m and 5 mm and a waviness average height Wa of 1.0 nm or less as measured by the contactless laser interference technique for measurement points in a measurement region surrounded by two concentric circles which is spaced from a center of a surface of the substrate by a predetermined distance. The waviness average height Wa is given by: Wa = 1 N ∑ i = 1 N &LeftBracketingBar; X I - X _ &RightBracketingBar; where Xi represents a measurement point value of each measurement point, {overscore (X)} representing an average value of the measurement point values, n representing the number of said measurement points.
摘要:
A defect inspection is performed for each of glass substrates by a surface defect detector. The distance from the center of the glass substrate to a detected defect, as a radius of a nonmagnetic region to be formed circular, is recorded along with an ID assigned to the glass substrate. Such defect information is recorded in a defect list using a printer or recorded in an RFID tag using an RFID writer. The defect list or the RFID tag is attached to a glass-substrate case. Each glass substrate and its defect information are in one-to-one correspondence and are provided to a customer as a magnetic disk manufacturer. Based on the obtained defect information, the customer manufactures magnetic disks each being a discrete track recording medium having the nonmagnetic region formed at the position where the defect is present.
摘要:
To provide a magnetic-disk glass substrate manufacturing method that can reduce the inner diameter dimensional error.A magnetic-disk glass substrate manufacturing method of this invention including a chemical strengthening step of bringing a plurality of glass substrates 102 into contact with chemical strengthening treatment solutions of a plurality of chemical strengthening treatment baths 130, respectively, to chemically strengthen the glass substrates further includes an inner diameter measuring step of measuring the inner diameter of each of the glass substrates 102 before the chemical strengthening step, a grasping step of grasping a variation of the inner diameter of the glass substrate 102 to be generated by the chemical strengthening step for each of the chemical strengthening treatment baths 130, and a combination determining step of determining the chemical strengthening treatment baths 130, that perform chemical strengthening, based on the variations so that the inner diameters of the glass substrates, whose inner diameters are measured, after the chemical strengthening step become a desired value. In the chemical strengthening step, the glass substrates 102 are chemically strengthened in the determined chemical strengthening treatment baths 130, respectively.
摘要:
To provide a magnetic-disk glass substrate manufacturing method that can reduce the inner diameter dimensional error.A magnetic-disk glass substrate manufacturing method of this invention including a chemical strengthening step of bringing a plurality of glass substrates 102 into contact with chemical strengthening treatment solutions of a plurality of chemical strengthening treatment baths 130, respectively, to chemically strengthen the glass substrates further includes an inner diameter measuring step of measuring the inner diameter of each of the glass substrates 102 before the chemical strengthening step, a grasping step of grasping a variation of the inner diameter of the glass substrate 102 to be generated by the chemical strengthening step for each of the chemical strengthening treatment baths 130, and a combination determining step of determining the chemical strengthening treatment baths 130, that perform chemical strengthening, based on the variations so that the inner diameters of the glass substrates, whose inner diameters are measured, after the chemical strengthening step become a desired value. In the chemical strengthening step, the glass substrates 102 are chemically strengthened in the determined chemical strengthening treatment baths 130, respectively.
摘要:
A defect inspection is performed for each of glass substrates by a surface defect detector. The distance from the center of the glass substrate to a detected defect, as a radius of a nonmagnetic region to be formed circular, is recorded along with an ID assigned to the glass substrate. Such defect information is recorded in a defect list using a printer or recorded in an RFID tag using an RFID writer. The defect list or the RFID tag is attached to a glass-substrate case. Each glass substrate and its defect information are in one-to-one correspondence and are provided to a customer as a magnetic disk manufacturer. Based on the obtained defect information, the customer manufactures magnetic disks each being a discrete track recording medium having the nonmagnetic region formed at the position where the defect is present.