# US 8,569,933 B2 · Piezoelectric multilayer component > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,569,933 B2 - Document ID: US8569933B2 - Status: Granted - Kind: B2 - Application number: 13/303,976 - Filed: 2011-11-23 - Published: 2012-05-17 - Granted: 2013-10-29 - Earliest claimed: 2009-05-29 - Assignees: Epcos AG - Applicants: Oliver Dernovsek; Alexander Glazunov - Inventors: Oliver Dernovsek; Alexander Glazunov - Web page: https://patentgrep.com/patent/US8569933B2 ## CPC - H10N 30/508: {adapted for alleviating internal stress, e.g. cracking control layers} - H10N 30/053: by integrally sintering piezoelectric or electrostrictive bodies and electrodes - H10N: ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR ## Abstract A piezoelectric multilayer component includes a stack of sintered piezoelectric layers and inner electrodes that are arranged there between. A piezoelectric layer includes at least one piezoelectric film. At least one of the piezoelectric films is designed as a weakening film, wherein the thickness of the weakening film is substantially smaller than the thickness of at least one of the other piezoelectric films. ## Claims ### Claim 1 A piezoelectric multilayer component, comprising: a stack of sintered piezoelectric layers; and internal electrodes arranged between the piezoelectric layers; wherein each piezoelectric layer comprises at least one piezoelectric sheet, wherein at least one of the piezoelectric sheets is embodied as a weakening sheet having a lower crack resistance than at least one other piezoelectric sheet, wherein a thickness of the weakening sheet is significantly less than a thickness of the at least one other piezoelectric sheet, wherein the piezoelectric sheets contain a ceramic material, and wherein the ceramic material of the weakening sheet differs from the ceramic material of the at least one other piezoelectric sheet in grain size. ### Claim 2 (depends on 1) The multilayer component according to claim 1, wherein the weakening sheet has an adhesive strength with respect to an adjoining piezoelectric sheet that is lower than an adhesive strength of another piezoelectric sheet with respect to a piezoelectric sheet adjoining the another piezoelectric sheet. ### Claim 3 (depends on 2) The multilayer component according to claim 2, wherein the lower adhesive strength of the weakening sheet results from a lower sintering activity of a material of the weakening sheet. ### Claim 4 (depends on 1) The multilayer component according to claim 1, wherein the thickness of the weakening sheet is in the range of 1 to 10 μm. ### Claim 5 (depends on 1) The multilayer component according to claim 1, wherein the weakening sheet is arranged between an adjoining piezoelectric sheet and an adjoining internal electrode and adjoins both the adjoining piezoelectric sheet and the adjoining internal electrode. ### Claim 6 (depends on 1) The multilayer component according to claim 1, wherein the weakening sheet is arranged within one of the piezoelectric layers. ### Claim 7 (depends on 1) The multilayer component according to claim 1, wherein a plurality of weakening sheets are arranged in a manner distributed over the stack. ### Claim 8 (depends on 1) The multilayer component according to claim 1, wherein the weakening sheet is structured in a plane perpendicular to a stacking direction of the stack. ### Claim 9 (depends on 8) The multilayer component according to claim 8, wherein the weakening sheet has cutouts. ### Claim 10 (depends on 1) The multilayer component according to claim 1, wherein the ceramic material of the weakening sheet comprises a ceramic powder having larger grains than a ceramic powder in the ceramic material of the at least one other piezoelectric sheet. ### Claim 11 (depends on 1) The multilayer component according to claim 1, wherein the ceramic material of the weakening sheet comprises a ceramic powder that is calcined at a higher temperature than a ceramic powder in the ceramic material of the at least one other piezoelectric sheet. ### Claim 12 (depends on 1) The multilayer component according to claim 1, wherein the ceramic material of the weakening sheet comprises a ceramic powder comprising less lead than a ceramic powder in the ceramic material of the at least one other piezoelectric sheet. ### Claim 13 (depends on 1) The multilayer component according to claim 1, wherein the ceramic material of the weakening sheet differs from the ceramic material of the at least one other piezoelectric sheet in calcination temperature. ### Claim 14 A piezoelectric multilayer component, comprising: a stack of sintered piezoelectric layers; and internal electrodes arranged between the piezoelectric layers; wherein each piezoelectric layer comprises at least one piezoelectric sheet, wherein at least one of the piezoelectric sheets is embodied as a weakening sheet having a lower crack resistance than at least one other piezoelectric sheet, wherein a thickness of the weakening sheet is significantly less than a thickness of the at least one other piezoelectric sheet, wherein the piezoelectric sheets contain a ceramic material, wherein the ceramic material of the weakening sheet differs from the ceramic material of the at least one other piezoelectric sheet in a content of lead oxide, and wherein a mole percentage of lead in the ceramic material of the weakening sheet is less than a mole percentage of lead in the ceramic material of the at least one other piezoelectric sheet. ### Claim 15 (depends on 14) The multilayer component according to claim 14, wherein the difference in the content of lead oxide comprises at least 1.5 mole percentage lead. ### Claim 16 (depends on 14) The multilayer component according to claim 14, wherein the weakening sheet has an adhesive strength with respect to an adjoining piezoelectric sheet that is lower than an adhesive strength of another piezoelectric sheet with respect to a piezoelectric sheet adjoining the another piezoelectric sheet. ### Claim 17 (depends on 14) The multilayer component according to claim 14, wherein the lead oxide of the ceramic material of the weakening sheet consists essentially of the elements lead and oxygen. ### Claim 18 (depends on 14) The multilayer component according to claim 14, wherein the thickness of the weakening sheet is in the range of 1 to 10 μm. ### Claim 19 (depends on 14) The multilayer component according to claim 14, wherein the weakening sheet is arranged between an adjoining piezoelectric sheet and an adjoining internal electrode and adjoins both the adjoining piezoelectric sheet and the adjoining internal electrode. ### Claim 20 (depends on 14) The multilayer component according to claim 14, wherein the weakening sheet is arranged within one of the piezoelectric layers.