# US 8,770,727 B2 · Piezoelectric element, piezoelectric actuator, liquid ejecting head and liquid ejecting apparatus > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,770,727 B2 - Document ID: US8770727B2 - Status: Granted - Kind: B2 - Application number: 13/176,101 - Filed: 2011-07-05 - Published: 2012-01-12 - Granted: 2014-07-08 - Earliest claimed: 2010-07-08 - Assignees: Seiko Epson Corporation - Applicants: Masao Nakayama - Inventors: Masao Nakayama - Web page: https://patentgrep.com/patent/US8770727B2 ## CPC - H10N 30/2047: {Membrane type} - B41J 2/14233: {of film type, deformed by bending and disposed on a diaphragm} - H10N: ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR - B41J: TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS ## Abstract A piezoelectric element includes a first electrode, a first piezoelectric layer which is formed at an upper side of the first electrode and at lateral sides to the first electrode, a porous layer which is formed so as to cover side surfaces of the first piezoelectric layer, and a second electrode which is formed at an upper side of the first piezoelectric layer and the porous layer. In the piezoelectric element, the porous layer contains at least one metal element constituting the first piezoelectric layer. ## Claims ### Claim 1 A piezoelectric element comprising: a first electrode; a first piezoelectric layer which is formed at an upper side of the first electrode and at lateral sides to the first electrode; a porous layer which is formed so as to cover side surfaces of the first piezoelectric layer; and a second electrode which is formed at an upper side of the first piezoelectric layer and the porous layer, wherein the porous layer contains at least one metal element constituting the first piezoelectric layer, the porous layer comprising a plurality of fine holes that thereby cause the layer to be porous. ### Claim 2 (depends on 1) The piezoelectric element according to claim 1, wherein density of the porous layer becomes larger toward the first piezoelectric layer. ### Claim 3 (depends on 2) A piezoelectric actuator, comprising the piezoelectric element according to claim 2. ### Claim 4 (depends on 3) A liquid ejecting head comprising: the piezoelectric actuator according to claim 3; and a pressure chamber which communicates with a nozzle hole discharging liquid, wherein a width of the pressure chamber along a short-side direction of the first electrode is larger than a width of the first piezoelectric layer along the short-side direction, and at least a part of the porous layer is located at the upper side of the pressure chamber. ### Claim 5 (depends on 4) A liquid ejecting apparatus comprising the liquid ejecting head according to claim 4. ### Claim 6 (depends on 1) The piezoelectric element according to claim 1, further including an insulating layer formed between the porous layer and the second electrode. ### Claim 7 (depends on 6) The piezoelectric element according to claim 6, wherein a Young's modulus of the insulating layer is smaller than a Young's modulus of the second electrode. ### Claim 8 (depends on 6) The piezoelectric element according to claim 6, wherein side surfaces of the insulating layer are inclined with respect to an upper surface of the first piezoelectric layer. ### Claim 9 (depends on 3) A piezoelectric actuator, comprising the piezoelectric element according to claim 3. ### Claim 10 (depends on 9) A liquid ejecting head comprising: the piezoelectric actuator according to claim 9; and a pressure chamber which communicates with a nozzle hole discharging liquid, wherein a width of the pressure chamber along a short-side direction of the first electrode is larger than a width of the first piezoelectric layer along the short-side direction, and at least a part of the porous layer is located at the upper side of the pressure chamber. ### Claim 11 (depends on 1) The piezoelectric element according to claim 1, further including a second piezoelectric layer which is formed between the first piezoelectric layer and the porous layer, and the second electrode. ### Claim 12 (depends on 11) The piezoelectric element according to claim 11, wherein a material of the second piezoelectric layer is the same as a material of the first piezoelectric layer. ### Claim 13 (depends on 1) The piezoelectric element according to claim 1, further including a third piezoelectric layer at the lower side of the porous layer. ### Claim 14 (depends on 13) The piezoelectric element according to claim 13, wherein a material of the third piezoelectric layer is the same as the material of the first piezoelectric layer. ### Claim 15 (depends on 1) The piezoelectric element according to claim 1, wherein the first electrode, the first piezoelectric layer and the second electrode form a laminated body, a plurality of laminated bodies are provided, the plurality of laminated bodies are arranged in line along a short-side direction of the first electrodes, the first electrodes are individual electrodes on the plurality of laminated bodies, the second electrode is a common electrode to the plurality of laminated bodies, and the porous layer is formed between the plurality of laminated bodies. ### Claim 16 (depends on 1) The piezoelectric element according to claim 1, wherein a material of the first piezoelectric layer is lead zirconate titanate. ### Claim 17 (depends on 1) A piezoelectric actuator, comprising the piezoelectric element according to claim 1. ### Claim 18 (depends on 17) A liquid ejecting head comprising: the piezoelectric actuator according to claim 17; and a pressure chamber which communicates with a nozzle hole discharging liquid, wherein a width of the pressure chamber along a short-side direction of the first electrode is larger than a width of the first piezoelectric layer along the short-side direction, and at least a part of the porous layer is located at the upper side of the pressure chamber. ### Claim 19 (depends on 18) A liquid ejecting apparatus comprising the liquid ejecting head according to claim 18.