# US 5,111,169 A · LC noise filter > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,111,169 A - Document ID: US5111169A - Status: Granted - Kind: A - Application number: 07/497,209 - Filed: 1990-03-22 - Granted: 1992-05-05 - Earliest claimed: 1989-03-23 - Inventors: Takeshi Ikeda - Web page: https://patentgrep.com/patent/US5111169A ## CPC - H03H 7/427: {Common-mode filters (H02J3/01 and H02M1/126 takes precedence)} - H01F 17/0006: {Printed inductances (printed coils for dynamo-electric machines H02K3/26; printed circuits H05K)} - H01F 38/48: {Common mode inductor for reducing or eliminating common mode noise on parallel lines} - H03H 2001/0078: {comprising spiral inductor on a substrate} - H03H 2001/0092: {Inductor filters, i.e. inductors whose parasitic capacitance is of relevance to consider it as filter} - H03H: IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS (waveguides, resonators, lines or other devices of the waveguide type H01P) - H01F: MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES ## Abstract An LC noise filter comprising a dielectric substrate, a plurality of concentrically adjacent spiral grooves provided in at least one surface of the substrate, and a plurality of inductor conductors provided in the respective spiral grooves. The inductor conductors are opposed to each other with the wall body between the grooves therebetween so as not to obstruct the magnetic path of the magnetic flux of the opposite inductor conductor. That is, a distribution constant LC noise filter having a sufficient capacitance and excellent electric characteristics without lowering the inductance of each inductor conductor is disclosed. ## Claims ### Claim 1 An LC noise filter comprising: a dielectric material; a plurality of spiral grooves provided in at least one surface of said dielectric material in such a manner as to be concentrically adjacent to each other; and a plurality of inductor conductors at least one of which is provided in each of said grooves; each of said inductor conductors forming a capacitor with the inductor conductor adjacent thereto with a wall body of said dielectric material therebetween. ### Claim 2 (depends on 1) An LC noise filter according to claim 1, wherein at least one of said conductors is an energizing conductor and at least one of said conductors is a grounding conductor, whereby said LC noise filter constitutes a normal mode LC noise filter. ### Claim 3 (depends on 1) An LC noise filter according to claim 1, wherein a first plurality of said conductors are energizing conductors and a second plurality of said conductors are shield conductors, at least one of said shield conductors being disposed so as to separate any two of said energizing conductors whereby said LC noise filter constitutes a common mode LC noise filter. ### Claim 4 (depends on 1) An LC noise filter according to claim 1, wherein said dielectric material is used as a substrate; said plurality of spiral grooves are provided in at least one surface of said substrate in such a manner as to be concentrically adjacent to each other; and at least one of said inductor conductors is provided in each of said grooves. ### Claim 5 (depends on 4) An LC noise filter according to claim 4, further comprising: a through hole provided at the center of said substrate; and a magnetic material surrounding said substrate for forming a magnetic path on the surface of said substrate. ### Claim 6 (depends on 4) An LC noise filter according to claim 4, wherein at least one of said conductors is an energizing conductor and at least one of said conductors is a grounding conductor, whereby said LC noise filter constitutes a normal mode LC noise filter. ### Claim 7 (depends on 4) An LC noise filter according to claim 4, wherein a first plurality of said conductors are energizing conductors and a second plurality of said conductors are shield conductors, at least one of said shield conductors separating any two of said energizing conductors whereby said LC noise filter constitutes a common mode LC noise filter. ### Claim 8 (depends on 1) An LC noise filter according to claim 1, wherein said dielectric material is formed into a thick substrate; said plurality of spiral grooves are formed in said substrate as deep grooves; and at least one of said inductor conductors is provided in each of said deep spiral grooves in such a manner as to be opposed to each other with said wall body therebetween. ### Claim 9 (depends on 8) An LC noise filter according to claim 8, wherein each of said spiral grooves is formed into a deep groove which penetrates through said substrate from said at least one surface to a back surface thereof. ### Claim 10 A multi-channel noise filter comprising: a substrate made of a dielectric material; and a plurality of LC noise filters arranged adjacently to each other on said substrate; each of said LC noise filters including: a plurality of spiral grooves provided in at least one surface of said substrate in such a manner as to be concentrically adjacent to each other; and a plurality of inductor conductors at least one of which is provided in each of said grooves; each of said inductor conductors forming a capacitor with the inductor conductor adjacent thereto with a wall body of said dielectric material therebetween. ### Claim 11 An LC noise filter comprising: a dielectric material; a spiral groove provided in at least one surface of said dielectric material; and at least one ground groove provided in at least one surface of said dielectric material in such a manner as to be adjacent to a part of said spiral groove; an inductor conductor provided in said spiral groove; a grounding block conductor provided in said ground groove; said inductor conductor forming a capacitor with the grounding block conductor adjacent thereto with a wall body of said dielectric material therebetween. ### Claim 12 (depends on 11) An LC noise filter according to claim 11, wherein said inductor conductor provided in said spiral groove is used as an energizing inductor conductor and constitutes a normal mode LC noise filter together with said grounding block conductor provided in said ground groove. ### Claim 13 (depends on 11) An LC noise filter according to claim 11, wherein at least two spiral grooves are provided in such a manner as to be concentrically adjacent to each other as said spiral groove, and energizing inductor conductors each of which is provided in each of said spiral grooves together with said grounding block conductor provided in said ground groove constitute a common mode LC noise filter. ### Claim 14 (depends on 11) An LC noise filter according to claim 11, wherein a plurality of said grounding block conductors are provided, and one of said grounding block conductors is disposed in proximity to an input or output terminal of said inductor conductor. ### Claim 15 (depends on 11) An LC noise filter according to claim 11, wherein said grounding block conductor includes a first block conductor disposed in proximity to an input terminal of said inductor conductor and a second block conductor disposed in proximity to an output terminal of said inductor conductor. ### Claim 16 (depends on 15) An LC noise filter according to claim 15, wherein said grounding block conductor includes a plurality of third block conductors disposed in such a manner as to be adjacent to a part of said inductor conductor between the input terminal and the output terminal of said inductor conductor. ### Claim 17 (depends on 11) An LC noise filter according to claim 11, wherein a plurality of grounding block conductors are intermittently provided between proximate lines of said inductor conductor so as to function as a shield conductor for preventing short circuit between the lines of said inductor conductor. ### Claim 18 (depends on 11) An LC noise filter according to claim 11, wherein said dielectric material forms a substrate; said spiral groove and said ground groove are provided in at least one surface of said substrate in such a manner as to be adjacent to each other; and said inductor conductor and said grounding block conductor are provided in each of said spiral groove and said ground groove, respectively. ### Claim 19 (depends on 11) An LC noise filter according to claim 11, wherein said dielectric is formed into a thick substrate; and said spiral groove is formed in said substrate as a deep groove. ### Claim 20 (depends on 18) An LC noise filter according to claim 18, wherein said spiral groove is formed into a deep groove which penetrates through said substrate from said at least one surface to a back surface thereof. ### Claim 21 (depends on 11) An LC noise filter according claim 11, further comprising: a through hole situated at the center of said spiral groove in said substrate; and a magnetic material surrounding said substrate so as to form a magnetic path on the surface of said substrate. ### Claim 22 A multi-channel noise filter comprising: a substrate made of a dielectric material; and a plurality of LC noise filters arranged adjacently to each other on said substrate; each of said LC noise filters including: a spiral groove provided in at least one surface of said substrate; at least one ground groove provided in at least one surface of said dielectric in such a manner as to be adjacent to a part of said spiral groove; an inductor conductor provided in said spiral groove; and a grounding block conductor provided in said ground groove; said inductor conductor forming a capacitor with a grounding block conductor adjacent thereto with a wall body of said dielectric material therebetween. ### Claim 23 An Lc noise filter comprising: an insulating substrate; a spiral inductor conductor provided on at least one surface of said substrate; and at least one grounding block conductor provided on at least one surface of said substrate in such a manner as to be adjacent to and on a same surface as a part of said inductor conductor; said inductor conductor forming a capacitor with the grounding block conductor adjacent thereto.