# US 5,350,618 A · Magnetic medium comprising a substrate having pits and grooves of specific shapes and depths > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,350,618 A - Document ID: US5350618A - Status: Granted - Kind: A - Application number: 07/842,057 - Filed: 1992-02-26 - Granted: 1994-09-27 - Earliest claimed: 1991-03-01 - Assignees: Teijin Seiki Co., Ltd. - Inventors: Masayuki Togawa; Kiyoshi Toyama - Web page: https://patentgrep.com/patent/US5350618A ## CPC - H01F 10/28: characterised by the composition of the substrate - G01D 5/14: influencing the magnitude of a current or voltage - H01F 1/0027: {Thick magnetic films (forming thick magnetic films H01F41/16)} - H01F 10/08: characterised by magnetic layers ({H01F10/32 takes precedence } ; applying thin magnetic films to substrates H01F41/14) - H01F 41/16: the magnetic material being applied in the form of particles, e.g. by serigraphy {, to form thick magnetic films or precursors therefor} (H01F41/18 {-H01F41/24} take precedence) - H01F 41/34: in patterns, e.g. by lithography - H02K 15/03: having permanent magnets - H02K 99/00: Subject matter not provided for in other groups of this subclass - Y10S 428/90: Magnetic feature - Y10S 430/143: Electron beam - Y10T 428/24479: including variation in thickness - Y10T 428/2457: Parallel ribs and/or grooves - Y10T 428/24579: with particulate matter - H01F: MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES - G01D: MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR - H02K: DYNAMO-ELECTRIC MACHINES (dynamo-electric relays H01H53/00; conversion of DC or AC input power into surge output power {H03K3/53}) - Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract A magnetic medium comprising a substrate formed with a stepped pit and a magnetic substance buried in the stepped pit. A method of manufacturing a magnetic medium comprising the steps of forming a first groove in a substrate by photoetching, forming a second groove in the first groove or in a portion adjacent to the first groove by the photoetching, the second groove being different in depth from the first groove, and burying magnetic substances into the first and second grooves. ## Claims ### Claim 1 A magnetic medium comprising: a substrate formed with a pit; and a hard magnetic substance filling said pit, said hard magnetic substance being divided into at least two sections by an imaginary plane at right angles to the surface of said substrate, said sections being different in thickness from each other, each of said sections having a constant thickness over the area of such section, and said hard magnetic substance being magnetized. ### Claim 2 (depends on 1) A magnetic medium as recited in claim 1, wherein said substrate comprises a silicon or silicon-containing substrate. ### Claim 3 A magnetic medium comprising: a substrate formed with a pit, the pit being divided into a plurality of grooves with partition portions of said substrate, and at least one of the grooves being different in depth from the remaining grooves; and hard magnetic substance filling in said grooves of said pit, each of said partition portions being smaller in width than each of the adjoining buried hard magnetic substances having such partition portion positioned therebetween, at least one of said hard magnetic substances being different in thickness from the remaining hard magnetic substances, each of said hard magnetic substances having a constant thickness over the area of such hard magnetic substance and said hard magnetic substances being magnetized. ### Claim 4 (depends on 3) A magnetic medium as recited in claim 3, wherein said substrate comprises a silicon or silicon-containing substrate. ### Claim 5 A magnetic medium comprising: a substrate with a plurality of pits disposed according to predetermined patterns, the depth of the pit being increased gradually toward the central portion of the pit; and hard magnetic substance filling said pits, each of said hard magnetic substances having at least three sections which are different in thickness from each other, the thickness of the hard magnetic substance being increased gradually toward the central section of the hard magnetic substance, each of said at least three sections of the hard magnetic substance having a constant thickness over the area of such section, and said hard magnetic substances being magnetized. ### Claim 6 (depends on 5) A magnetic medium as recited in claim 5, wherein said substrate comprises a silicon or silicon-containing substrate. ### Claim 7 A magnetic medium comprising: a substrate with a pit disposed according to predetermined patterns, said pit comprising at least three grooves adjacent to one another, the depths of said at least three grooves being increased gradually toward a center groove of said at least three grooves; and hard magnetic substances filling said at least three grooves of said pit, the thicknesses of the hard magnetic substances being increased gradually toward a center substance of said hard magnetic substances, and said hard magnetic substances having been magnetized. ### Claim 8 (depends on 7) A magnetic medium as recited in claim 7, wherein said substrate comprises a silicon or silicon-containing substrate.