CN117957858A - Piezoelectric element and electroacoustic transducer - Google Patents
Piezoelectric element and electroacoustic transducer Download PDFInfo
- Publication number
- CN117957858A CN117957858A CN202280060037.6A CN202280060037A CN117957858A CN 117957858 A CN117957858 A CN 117957858A CN 202280060037 A CN202280060037 A CN 202280060037A CN 117957858 A CN117957858 A CN 117957858A
- Authority
- CN
- China
- Prior art keywords
- piezoelectric
- layer
- piezoelectric element
- protruding portion
- electrode layer
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 239000010410 layer Substances 0.000 claims abstract description 249
- 239000011241 protective layer Substances 0.000 claims abstract description 70
- 238000003475 lamination Methods 0.000 claims abstract description 10
- 238000010030 laminating Methods 0.000 claims abstract description 8
- 239000002245 particle Substances 0.000 claims description 43
- 239000002861 polymer material Substances 0.000 claims description 42
- 229920000642 polymer Polymers 0.000 claims description 33
- 239000011159 matrix material Substances 0.000 claims description 29
- 239000002131 composite material Substances 0.000 claims description 24
- 230000020169 heat generation Effects 0.000 abstract description 11
- 239000010408 film Substances 0.000 description 125
- 239000000463 material Substances 0.000 description 34
- 239000012790 adhesive layer Substances 0.000 description 29
- 238000000034 method Methods 0.000 description 28
- ZMXDDKWLCZADIW-UHFFFAOYSA-N N,N-Dimethylformamide Chemical compound CN(C)C=O ZMXDDKWLCZADIW-UHFFFAOYSA-N 0.000 description 18
- 239000000853 adhesive Substances 0.000 description 18
- 230000001070 adhesive effect Effects 0.000 description 18
- -1 cyanoethyl hydroxy sucrose Chemical compound 0.000 description 18
- 230000010287 polarization Effects 0.000 description 16
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 15
- 229910052802 copper Inorganic materials 0.000 description 14
- 239000010949 copper Substances 0.000 description 14
- 230000008602 contraction Effects 0.000 description 12
- 238000010438 heat treatment Methods 0.000 description 10
- 125000001731 2-cyanoethyl group Chemical group [H]C([H])(*)C([H])([H])C#N 0.000 description 8
- 238000005452 bending Methods 0.000 description 8
- 230000000052 comparative effect Effects 0.000 description 8
- 238000005259 measurement Methods 0.000 description 8
- 229920000139 polyethylene terephthalate Polymers 0.000 description 8
- 239000005020 polyethylene terephthalate Substances 0.000 description 8
- 239000000758 substrate Substances 0.000 description 8
- 238000010586 diagram Methods 0.000 description 7
- 229910052451 lead zirconate titanate Inorganic materials 0.000 description 7
- ZWEHNKRNPOVVGH-UHFFFAOYSA-N 2-Butanone Chemical compound CCC(C)=O ZWEHNKRNPOVVGH-UHFFFAOYSA-N 0.000 description 6
- 229920001577 copolymer Polymers 0.000 description 6
- 230000007246 mechanism Effects 0.000 description 6
- 229920005989 resin Polymers 0.000 description 6
- 239000011347 resin Substances 0.000 description 6
- 238000003860 storage Methods 0.000 description 6
- 239000002033 PVDF binder Substances 0.000 description 5
- 239000011248 coating agent Substances 0.000 description 5
- 238000000576 coating method Methods 0.000 description 5
- 230000005684 electric field Effects 0.000 description 5
- 229920002981 polyvinylidene fluoride Polymers 0.000 description 5
- 238000012545 processing Methods 0.000 description 5
- 238000005096 rolling process Methods 0.000 description 5
- 239000010409 thin film Substances 0.000 description 5
- 229920002284 Cellulose triacetate Polymers 0.000 description 4
- 239000004697 Polyetherimide Substances 0.000 description 4
- 239000004642 Polyimide Substances 0.000 description 4
- 239000004734 Polyphenylene sulfide Substances 0.000 description 4
- 239000004743 Polypropylene Substances 0.000 description 4
- NNLVGZFZQQXQNW-ADJNRHBOSA-N [(2r,3r,4s,5r,6s)-4,5-diacetyloxy-3-[(2s,3r,4s,5r,6r)-3,4,5-triacetyloxy-6-(acetyloxymethyl)oxan-2-yl]oxy-6-[(2r,3r,4s,5r,6s)-4,5,6-triacetyloxy-2-(acetyloxymethyl)oxan-3-yl]oxyoxan-2-yl]methyl acetate Chemical compound O([C@@H]1O[C@@H]([C@H]([C@H](OC(C)=O)[C@H]1OC(C)=O)O[C@H]1[C@@H]([C@@H](OC(C)=O)[C@H](OC(C)=O)[C@@H](COC(C)=O)O1)OC(C)=O)COC(=O)C)[C@@H]1[C@@H](COC(C)=O)O[C@@H](OC(C)=O)[C@H](OC(C)=O)[C@H]1OC(C)=O NNLVGZFZQQXQNW-ADJNRHBOSA-N 0.000 description 4
- 229910052782 aluminium Inorganic materials 0.000 description 4
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 4
- 239000004020 conductor Substances 0.000 description 4
- 238000001514 detection method Methods 0.000 description 4
- 239000006185 dispersion Substances 0.000 description 4
- 230000009477 glass transition Effects 0.000 description 4
- 239000003960 organic solvent Substances 0.000 description 4
- 239000003973 paint Substances 0.000 description 4
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 4
- 229920003229 poly(methyl methacrylate) Polymers 0.000 description 4
- 229920001601 polyetherimide Polymers 0.000 description 4
- 229920001721 polyimide Polymers 0.000 description 4
- 239000004926 polymethyl methacrylate Substances 0.000 description 4
- 229920000069 polyphenylene sulfide Polymers 0.000 description 4
- 229920001155 polypropylene Polymers 0.000 description 4
- 239000007787 solid Substances 0.000 description 4
- 229920002799 BoPET Polymers 0.000 description 3
- 239000004698 Polyethylene Substances 0.000 description 3
- 239000004793 Polystyrene Substances 0.000 description 3
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 3
- 239000000470 constituent Substances 0.000 description 3
- 230000007423 decrease Effects 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 229910003472 fullerene Inorganic materials 0.000 description 3
- 230000001771 impaired effect Effects 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 229910052751 metal Inorganic materials 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 229920000573 polyethylene Polymers 0.000 description 3
- 229910052709 silver Inorganic materials 0.000 description 3
- 239000004332 silver Substances 0.000 description 3
- 238000004544 sputter deposition Methods 0.000 description 3
- 238000001771 vacuum deposition Methods 0.000 description 3
- 238000007740 vapor deposition Methods 0.000 description 3
- RSWGJHLUYNHPMX-UHFFFAOYSA-N Abietic-Saeure Natural products C12CCC(C(C)C)=CC2=CCC2C1(C)CCCC2(C)C(O)=O RSWGJHLUYNHPMX-UHFFFAOYSA-N 0.000 description 2
- 229920000856 Amylose Polymers 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 2
- KDLHZDBZIXYQEI-UHFFFAOYSA-N Palladium Chemical compound [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 description 2
- KHPCPRHQVVSZAH-HUOMCSJISA-N Rosin Natural products O(C/C=C/c1ccccc1)[C@H]1[C@H](O)[C@@H](O)[C@@H](O)[C@@H](CO)O1 KHPCPRHQVVSZAH-HUOMCSJISA-N 0.000 description 2
- PPBRXRYQALVLMV-UHFFFAOYSA-N Styrene Chemical compound C=CC1=CC=CC=C1 PPBRXRYQALVLMV-UHFFFAOYSA-N 0.000 description 2
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 2
- 241000607479 Yersinia pestis Species 0.000 description 2
- 239000003522 acrylic cement Substances 0.000 description 2
- 229910045601 alloy Inorganic materials 0.000 description 2
- 239000000956 alloy Substances 0.000 description 2
- 229910002113 barium titanate Inorganic materials 0.000 description 2
- JRPBQTZRNDNNOP-UHFFFAOYSA-N barium titanate Chemical compound [Ba+2].[Ba+2].[O-][Ti]([O-])([O-])[O-] JRPBQTZRNDNNOP-UHFFFAOYSA-N 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 2
- 229910052799 carbon Inorganic materials 0.000 description 2
- 229920002678 cellulose Polymers 0.000 description 2
- 239000001913 cellulose Substances 0.000 description 2
- 239000000919 ceramic Substances 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 125000004093 cyano group Chemical group *C#N 0.000 description 2
- 125000004122 cyclic group Chemical group 0.000 description 2
- JHIVVAPYMSGYDF-UHFFFAOYSA-N cyclohexanone Chemical compound O=C1CCCCC1 JHIVVAPYMSGYDF-UHFFFAOYSA-N 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 238000000605 extraction Methods 0.000 description 2
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 2
- 229910052737 gold Inorganic materials 0.000 description 2
- 239000010931 gold Substances 0.000 description 2
- AMGQUBHHOARCQH-UHFFFAOYSA-N indium;oxotin Chemical compound [In].[Sn]=O AMGQUBHHOARCQH-UHFFFAOYSA-N 0.000 description 2
- 239000000155 melt Substances 0.000 description 2
- 150000002739 metals Chemical class 0.000 description 2
- 238000007747 plating Methods 0.000 description 2
- 229910052697 platinum Inorganic materials 0.000 description 2
- 239000004417 polycarbonate Substances 0.000 description 2
- 229920000515 polycarbonate Polymers 0.000 description 2
- 239000011112 polyethylene naphthalate Substances 0.000 description 2
- 229920005672 polyolefin resin Polymers 0.000 description 2
- 229920000131 polyvinylidene Polymers 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- 239000000523 sample Substances 0.000 description 2
- 238000003756 stirring Methods 0.000 description 2
- 150000003505 terpenes Chemical class 0.000 description 2
- 235000007586 terpenes Nutrition 0.000 description 2
- 229920001169 thermoplastic Polymers 0.000 description 2
- 239000004416 thermosoftening plastic Substances 0.000 description 2
- KHPCPRHQVVSZAH-UHFFFAOYSA-N trans-cinnamyl beta-D-glucopyranoside Natural products OC1C(O)C(O)C(CO)OC1OCC=CC1=CC=CC=C1 KHPCPRHQVVSZAH-UHFFFAOYSA-N 0.000 description 2
- 229920002554 vinyl polymer Polymers 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- KXJGSNRAQWDDJT-UHFFFAOYSA-N 1-acetyl-5-bromo-2h-indol-3-one Chemical compound BrC1=CC=C2N(C(=O)C)CC(=O)C2=C1 KXJGSNRAQWDDJT-UHFFFAOYSA-N 0.000 description 1
- VKNASXZDGZNEDA-UHFFFAOYSA-N 2-cyanoethyl 2-methylprop-2-enoate Chemical compound CC(=C)C(=O)OCCC#N VKNASXZDGZNEDA-UHFFFAOYSA-N 0.000 description 1
- AEPWOCLBLLCOGZ-UHFFFAOYSA-N 2-cyanoethyl prop-2-enoate Chemical compound C=CC(=O)OCCC#N AEPWOCLBLLCOGZ-UHFFFAOYSA-N 0.000 description 1
- XCKPLVGWGCWOMD-YYEYMFTQSA-N 3-[[(2r,3r,4s,5r,6r)-6-[(2s,3s,4r,5r)-3,4-bis(2-cyanoethoxy)-2,5-bis(2-cyanoethoxymethyl)oxolan-2-yl]oxy-3,4,5-tris(2-cyanoethoxy)oxan-2-yl]methoxy]propanenitrile Chemical compound N#CCCO[C@H]1[C@H](OCCC#N)[C@@H](COCCC#N)O[C@@]1(COCCC#N)O[C@@H]1[C@H](OCCC#N)[C@@H](OCCC#N)[C@H](OCCC#N)[C@@H](COCCC#N)O1 XCKPLVGWGCWOMD-YYEYMFTQSA-N 0.000 description 1
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 description 1
- 101100112111 Caenorhabditis elegans cand-1 gene Proteins 0.000 description 1
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 1
- QSAMQSXFHVHODR-UHFFFAOYSA-N Cl.C=CC#N Chemical compound Cl.C=CC#N QSAMQSXFHVHODR-UHFFFAOYSA-N 0.000 description 1
- FBPFZTCFMRRESA-FSIIMWSLSA-N D-Glucitol Natural products OC[C@H](O)[C@H](O)[C@@H](O)[C@H](O)CO FBPFZTCFMRRESA-FSIIMWSLSA-N 0.000 description 1
- JVTAAEKCZFNVCJ-UWTATZPHSA-N D-lactic acid Chemical compound C[C@@H](O)C(O)=O JVTAAEKCZFNVCJ-UWTATZPHSA-N 0.000 description 1
- YCKRFDGAMUMZLT-UHFFFAOYSA-N Fluorine atom Chemical compound [F] YCKRFDGAMUMZLT-UHFFFAOYSA-N 0.000 description 1
- 229920000663 Hydroxyethyl cellulose Polymers 0.000 description 1
- 239000004354 Hydroxyethyl cellulose Substances 0.000 description 1
- 229920002153 Hydroxypropyl cellulose Polymers 0.000 description 1
- VQTUBCCKSQIDNK-UHFFFAOYSA-N Isobutene Chemical group CC(C)=C VQTUBCCKSQIDNK-UHFFFAOYSA-N 0.000 description 1
- 229920000877 Melamine resin Polymers 0.000 description 1
- 239000004640 Melamine resin Substances 0.000 description 1
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 1
- 229920000459 Nitrile rubber Polymers 0.000 description 1
- ISWSIDIOOBJBQZ-UHFFFAOYSA-N Phenol Chemical compound OC1=CC=CC=C1 ISWSIDIOOBJBQZ-UHFFFAOYSA-N 0.000 description 1
- 229920001609 Poly(3,4-ethylenedioxythiophene) Polymers 0.000 description 1
- 239000004372 Polyvinyl alcohol Substances 0.000 description 1
- 229920001328 Polyvinylidene chloride Polymers 0.000 description 1
- 229930006000 Sucrose Natural products 0.000 description 1
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 1
- 229920001807 Urea-formaldehyde Polymers 0.000 description 1
- BZHJMEDXRYGGRV-UHFFFAOYSA-N Vinyl chloride Chemical compound ClC=C BZHJMEDXRYGGRV-UHFFFAOYSA-N 0.000 description 1
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 229920000180 alkyd Polymers 0.000 description 1
- 239000011230 binding agent Substances 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 229910052797 bismuth Inorganic materials 0.000 description 1
- JCXGWMGPZLAOME-UHFFFAOYSA-N bismuth atom Chemical compound [Bi] JCXGWMGPZLAOME-UHFFFAOYSA-N 0.000 description 1
- 229920001400 block copolymer Polymers 0.000 description 1
- 238000009529 body temperature measurement Methods 0.000 description 1
- 238000005266 casting Methods 0.000 description 1
- 239000003638 chemical reducing agent Substances 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 239000011651 chromium Substances 0.000 description 1
- 239000008199 coating composition Substances 0.000 description 1
- 229920001940 conductive polymer Polymers 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 239000011889 copper foil Substances 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 229940022769 d- lactic acid Drugs 0.000 description 1
- 238000013016 damping Methods 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 238000009713 electroplating Methods 0.000 description 1
- 150000002148 esters Chemical class 0.000 description 1
- 125000002573 ethenylidene group Chemical group [*]=C=C([H])[H] 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 229920006248 expandable polystyrene Polymers 0.000 description 1
- 238000001125 extrusion Methods 0.000 description 1
- 238000011049 filling Methods 0.000 description 1
- 229920005570 flexible polymer Polymers 0.000 description 1
- 239000011737 fluorine Substances 0.000 description 1
- 229910052731 fluorine Inorganic materials 0.000 description 1
- 239000011888 foil Substances 0.000 description 1
- 238000000227 grinding Methods 0.000 description 1
- 238000007731 hot pressing Methods 0.000 description 1
- 235000019447 hydroxyethyl cellulose Nutrition 0.000 description 1
- 239000001863 hydroxypropyl cellulose Substances 0.000 description 1
- 235000010977 hydroxypropyl cellulose Nutrition 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 230000001788 irregular Effects 0.000 description 1
- 229910052746 lanthanum Inorganic materials 0.000 description 1
- FZLIPJUXYLNCLC-UHFFFAOYSA-N lanthanum atom Chemical compound [La] FZLIPJUXYLNCLC-UHFFFAOYSA-N 0.000 description 1
- HFGPZNIAWCZYJU-UHFFFAOYSA-N lead zirconate titanate Chemical compound [O-2].[O-2].[O-2].[O-2].[O-2].[Ti+4].[Zr+4].[Pb+2] HFGPZNIAWCZYJU-UHFFFAOYSA-N 0.000 description 1
- 239000004973 liquid crystal related substance Substances 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 239000000113 methacrylic resin Substances 0.000 description 1
- 239000010445 mica Substances 0.000 description 1
- 229910052618 mica group Inorganic materials 0.000 description 1
- 230000000116 mitigating effect Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 229910052750 molybdenum Inorganic materials 0.000 description 1
- 239000011733 molybdenum Substances 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 239000012299 nitrogen atmosphere Substances 0.000 description 1
- 229910052763 palladium Inorganic materials 0.000 description 1
- 239000000123 paper Substances 0.000 description 1
- 239000003208 petroleum Substances 0.000 description 1
- 239000005011 phenolic resin Substances 0.000 description 1
- 229920003023 plastic Polymers 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
- 238000005498 polishing Methods 0.000 description 1
- 229920001432 poly(L-lactide) Polymers 0.000 description 1
- 229920001490 poly(butyl methacrylate) polymer Polymers 0.000 description 1
- 229920001084 poly(chloroprene) Polymers 0.000 description 1
- 229920000172 poly(styrenesulfonic acid) Polymers 0.000 description 1
- 229920002401 polyacrylamide Polymers 0.000 description 1
- 229920000058 polyacrylate Polymers 0.000 description 1
- 229920001748 polybutylene Polymers 0.000 description 1
- 229920000728 polyester Polymers 0.000 description 1
- 229920001195 polyisoprene Polymers 0.000 description 1
- 229920002223 polystyrene Polymers 0.000 description 1
- 229940005642 polystyrene sulfonic acid Drugs 0.000 description 1
- 239000011118 polyvinyl acetate Substances 0.000 description 1
- 229920002689 polyvinyl acetate Polymers 0.000 description 1
- 229920002451 polyvinyl alcohol Polymers 0.000 description 1
- 239000005033 polyvinylidene chloride Substances 0.000 description 1
- 238000010248 power generation Methods 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 238000010298 pulverizing process Methods 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 238000005245 sintering Methods 0.000 description 1
- 239000006104 solid solution Substances 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 239000000600 sorbitol Substances 0.000 description 1
- 229920003048 styrene butadiene rubber Polymers 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 239000005720 sucrose Substances 0.000 description 1
- 229920003051 synthetic elastomer Polymers 0.000 description 1
- 239000005061 synthetic rubber Substances 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 238000001931 thermography Methods 0.000 description 1
- 229920005992 thermoplastic resin Polymers 0.000 description 1
- 229920001187 thermosetting polymer Polymers 0.000 description 1
- 239000011135 tin Substances 0.000 description 1
- 229910052718 tin Inorganic materials 0.000 description 1
- 239000010936 titanium Substances 0.000 description 1
- 229910052719 titanium Inorganic materials 0.000 description 1
- 238000007738 vacuum evaporation Methods 0.000 description 1
- 229920001567 vinyl ester resin Polymers 0.000 description 1
- 239000003190 viscoelastic substance Substances 0.000 description 1
- 239000011345 viscous material Substances 0.000 description 1
- 210000001260 vocal cord Anatomy 0.000 description 1
- 229910000859 α-Fe Inorganic materials 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B06—GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS IN GENERAL
- B06B—METHODS OR APPARATUS FOR GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS OF INFRASONIC, SONIC, OR ULTRASONIC FREQUENCY, e.g. FOR PERFORMING MECHANICAL WORK IN GENERAL
- B06B1/00—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency
- B06B1/02—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy
- B06B1/06—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy operating with piezoelectric effect or with electrostriction
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R17/00—Piezoelectric transducers; Electrostrictive transducers
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R17/00—Piezoelectric transducers; Electrostrictive transducers
- H04R17/02—Microphones
Abstract
The invention provides a piezoelectric element and an electroacoustic transducer, which can restrain heat generation and restrain sound pressure deviation in a piezoelectric element formed by laminating piezoelectric films. A piezoelectric element is formed by laminating a plurality of layers by folding back a piezoelectric film having a piezoelectric layer, electrode layers provided on both sides of the piezoelectric layer, and a protective layer provided on the electrode layers, wherein the piezoelectric element has a protruding portion protruding from a lamination portion where 2 or more layers of the piezoelectric film are laminated in a plan view, the protruding portion has a connection portion for connecting the electrode layers and an external power source, a ratio of an area of the protruding portion to an area of the lamination portion is in a range of 0.02 to 0.3, and a length of a side where the protruding portion contacts the lamination portion is 4mm or more.
Description
Technical Field
The present invention relates to a piezoelectric element and an electroacoustic transducer.
Background
Piezoelectric elements are used in various applications as so-called exciters (excitons) which are mounted in contact with various articles to vibrate the articles and emit sound. For example, it is possible to make these vibrations emit sound instead of a speaker by installing an exciter in an image display panel, a screen, or the like.
As the piezoelectric element, a piezoelectric film in which a piezoelectric layer is sandwiched between an electrode layer and a protective layer has been proposed. In addition, it has been proposed to use a piezoelectric element in which piezoelectric films are laminated in a plurality of layers.
For example, patent document 1 describes a piezoelectric film including: a polymer composite piezoelectric body in which piezoelectric particles are dispersed in a matrix containing a polymer material; and electrode layers formed on both sides of the polymer composite piezoelectric body, wherein the loss tangent at a frequency of 1kHz at the time of measuring dynamic viscoelasticity has a maximum value of 0.1 or more in a temperature range of more than 50 ℃ and 150 ℃ or less, and a value of 0.08 or more at 50 ℃. Patent document 1 describes a piezoelectric element in which piezoelectric films are folded back 1 or more times and laminated in a plurality of layers.
Technical literature of the prior art
Patent literature
Patent document 1: international publication No. 2020/196850
Disclosure of Invention
Technical problem to be solved by the invention
The piezoelectric element formed by folding the piezoelectric film is attached to the vibration plate and vibrates the vibration plate, whereby a sound is emitted from the vibration plate. In order to connect an external power source to the electrode layer of such a piezoelectric element, it is conceivable to provide a protruding portion protruding in the planar direction from the laminated portion on which the piezoelectric film is laminated, and to connect an external power source to the electrode layer at the protruding portion. When a voltage is applied from a connection portion between an electrode layer provided in a protruding portion and an external power supply in order to drive a piezoelectric element, the protruding portion generates significant heat, and in the worst case, thermal runaway may occur, which may prevent continuous driving. In order to suppress such heat generation, the area of the protruding portion is preferably large.
However, according to the study of the present inventors, it is found that when a piezoelectric element having a large area of a plurality of protruding portions is fabricated to measure the sound pressure, there is a problem that the variation in sound pressure, particularly in the high frequency band, becomes large.
The present invention has been made to solve the above-described problems of the related art, and an object of the present invention is to provide a piezoelectric element and an electroacoustic transducer, which can suppress heat generation and suppress variation in sound pressure in a piezoelectric element formed by stacking piezoelectric films.
Means for solving the technical problems
In order to solve the above problems, the present invention has the following configuration.
[1] A piezoelectric element is formed by laminating a plurality of piezoelectric films by folding back the piezoelectric films 1 or more times, the piezoelectric films having piezoelectric layers, electrode layers provided on both sides of the piezoelectric layers, and protective layers provided on the electrode layers, wherein,
The piezoelectric element has a protruding portion protruding from a laminated portion where 2 or more piezoelectric films are laminated in a plan view,
The protruding portion has a connection portion for connecting the electrode layer with an external power source,
The ratio of the area of the protruding portion to the area of the laminated portion is in the range of 0.02 to 0.3, and the length of the side of the protruding portion in contact with the laminated portion is 4mm or more.
[2] The piezoelectric element according to [1], wherein,
The piezoelectric element has a plurality of protruding portions,
The ratio of the total area of the protruding portions to the area of the laminated portion is in the range of 0.02 to 0.3,
The length of the side of each protruding portion, which is in contact with the laminated portion, is 4mm or more.
[3] The piezoelectric element according to [2], wherein,
The number of the protruding parts is 12 or less.
[4] The piezoelectric element according to any one of [1] to [3], wherein,
The protruding portion has a rectangular shape in plan view.
[5] The piezoelectric element according to any one of [1] to [4], wherein,
The piezoelectric layer is composed of a polymer composite piezoelectric body including piezoelectric particles in a matrix including a polymer material.
[6] An electroacoustic transducer formed by attaching the piezoelectric element of any one of [1] to [5] to a vibration plate.
[7] The electroacoustic transducer of [6], wherein,
The lamination portion of the side surface of the piezoelectric element having the protruding portion is adhered to the vibration plate.
Effects of the invention
According to the present invention, it is possible to provide a piezoelectric element and an electroacoustic transducer capable of suppressing heat generation and suppressing variation in sound pressure in a piezoelectric element formed by laminating piezoelectric films.
Drawings
Fig. 1 is a schematic view showing an example of a piezoelectric element according to the present invention.
Fig. 2 is a perspective view of the piezoelectric element shown in fig. 1.
Fig. 3 is a plan view of the piezoelectric element shown in fig. 1.
Fig. 4 is a diagram for explaining the area of the laminated portion, the area of the protruding portion, and the length of the side where the protruding portion contacts the laminated portion.
Fig. 5 is a plan view schematically showing another example of the piezoelectric element of the present invention.
Fig. 6 is a plan view schematically showing another example of the piezoelectric element of the present invention.
Fig. 7 is a plan view schematically showing another example of the piezoelectric element of the present invention.
Fig. 8 is a plan view schematically showing another example of the piezoelectric element of the present invention.
Fig. 9 is a conceptual diagram for explaining an example of a method of producing a piezoelectric film.
Fig. 10 is a conceptual diagram for explaining an example of a method of producing a piezoelectric film.
Fig. 11 is a conceptual diagram for explaining an example of a method of producing a piezoelectric film.
Fig. 12 is a conceptual diagram for explaining an example of a method of producing a piezoelectric film.
Fig. 13 is a diagram schematically showing an example of the electroacoustic transducer of the present invention having the piezoelectric element of the present invention.
Detailed Description
Hereinafter, the piezoelectric element and the electroacoustic transducer according to the present invention will be described in detail based on preferred embodiments shown in the drawings.
The following description of the constituent elements is sometimes made based on the representative embodiments of the present invention, but the present invention is not limited to these embodiments.
In the present specification, the numerical range indicated by the term "to" means a range including the numerical values before and after the term "to" as the lower limit value and the upper limit value.
[ Piezoelectric element ]
The piezoelectric element of the present invention is formed by laminating a piezoelectric film having a piezoelectric layer, electrode layers provided on both sides of the piezoelectric layer, and a protective layer provided on the electrode layers, by folding back the piezoelectric film 1 or more times,
The piezoelectric element has a protruding portion protruding from a laminated portion where 2 or more piezoelectric films are laminated in a plan view,
The protruding portion has a connection portion for connecting the electrode layer with an external power source,
The ratio of the area of the protruding portion to the area of the laminated portion is in the range of 0.02 to 0.3, and the length of the side of the protruding portion in contact with the laminated portion is 4mm or more.
Fig. 1 is a side view schematically showing an example of the piezoelectric element of the present invention. Fig. 2 shows a perspective view of the piezoelectric element of fig. 1. Fig. 3 shows a plan view of the piezoelectric element of fig. 1. The plan view is a view from the lamination direction in which the piezoelectric film 10 is laminated in a plurality of layers.
The piezoelectric element 50a shown in fig. 1 to 3 is formed by laminating 5 laminated films 10 by folding back 1 rectangular piezoelectric film 104 times in one direction. That is, the piezoelectric element 50a is a laminated piezoelectric element in which 5 laminated films 10 are laminated.
In fig. 2, although the structure of the piezoelectric element 50a is omitted for the sake of simplifying the drawing, the piezoelectric film 10 has electrode layers on both sides of the piezoelectric layer 20, and has a protective layer by covering both electrode layers.
In the following description, the direction in which the piezoelectric film 10 is folded (horizontal direction in fig. 1) is referred to as a folding direction.
As shown in fig. 1, the piezoelectric element 50a has a protruding portion 10a protruding outward in the plane direction from the laminated portion 10b of the laminated 5-layer piezoelectric film 10. That is, the piezoelectric element 50a is provided with the protruding portion 10a such that, when 1 piezoelectric film 10 is folded back 4 times, the length in the folding back direction is made substantially the same among the 4 layers from the layer on the lower surface side in fig. 1, the length of the piezoelectric film 10 which is the layer on the uppermost surface side is made longer than the piezoelectric films 10 of the other layers, and one end in the folding back direction is made not to overlap the piezoelectric films 10 of the other layers.
The layers of the piezoelectric film 10 adjacent to each other in the laminated portion 10b are adhered to each other by the adhesive layer 14.
In the present invention, the lamination portion 10b is a region where the piezoelectric film is overlapped by 2 layers or more in plan view, that is, when the piezoelectric element is viewed from above (or below) in fig. 1. That is, as shown in fig. 3, the region where the layers of the piezoelectric film 10 overlap by 5 layers is the lamination portion 10b.
On the other hand, the protruding portion 10a is a region protruding in the planar direction from the laminated portion 10b, and is a region that does not overlap with another layer in a plan view. In the example shown in fig. 1, the right end of the uppermost layer in the drawing is a protruding portion 10a.
As shown in fig. 3, a connection portion 40 for connecting the 1 st electrode layer 24 and the 2 nd electrode layer 26 (hereinafter, also referred to as electrode layers) and the external electrode is formed in the protruding portion 10 a. In the illustrated example, the connection portion 40 is provided by forming a through hole in the protective layers (the 1 st protective layer 28 and the 2 nd protective layer 30) of the protruding portion 10a and exposing the electrode layer. The method of forming the through hole is not limited, and may be performed by a known method such as laser processing, dissolution removal using a solvent, and mechanical processing such as mechanical polishing, depending on the material for forming the protective layer.
The connection portion 40 is filled with a known conductive material such as a conductive metal paste such as silver paste, a conductive carbon paste, or a conductive nano ink, and is connected to a wiring connected to an external power source.
The connection method between the electrode and the wiring in the protruding portion 10a is not limited, and various known methods can be used.
The piezoelectric element 50a of the present invention drives the piezoelectric element 50a by applying a voltage to the electrode layer using an external power source through the connection portion 40 provided in the protruding portion 10 a. When the piezoelectric element 50a is driven, the piezoelectric element 50a expands and contracts in the plane direction, and the vibration plate to which the piezoelectric element 50a is attached is bent, and as a result, the vibration plate vibrates to emit sound. The vibration plate vibrates according to the magnitude of the driving voltage applied to the piezoelectric element 50a, and emits sound corresponding to the driving voltage applied to the piezoelectric element 50a.
That is, the piezoelectric element 50a can function as an exciter.
However, as described above, when a voltage is applied from the connection portion 40 between the electrode layer provided in the protruding portion 10a and the external power supply in order to drive the piezoelectric element 50a, the protruding portion 10a generates significant heat, and in the worst case, thermal runaway may occur, and continuous driving may not be possible. In order to suppress such heat generation, the area of the protruding portion 10a is preferably large.
However, according to the study of the present inventors, it is found that when the piezoelectric element 50a having a large area of the plurality of protruding portions 10a is fabricated to measure the sound pressure, there is a problem that the sound pressure is deviated, particularly, the sound pressure is deviated in a high frequency band.
In contrast, in the piezoelectric element 50a of the present invention, the ratio Ps (=sa/Sb) of the area Sa of the protruding portion 10a to the area Sb of the laminated portion 10b is in the range of 0.02 to 0.3, and the length Ya of the side of the protruding portion 10a in contact with the laminated portion 10b is 4mm or more.
If the ratio Ps of the area Sa of the protruding portion 10a to the area Sb of the laminated portion 10b is too small, that is, if the area Sa of the protruding portion 10a is too small, the current density becomes high in the protruding portion 10a when a voltage is applied to the piezoelectric element 50 a. Therefore, significant heat generation is caused in the protruding portion 10 a. If the length Ya of the side of the protruding portion 10a in contact with the laminated portion 10b is too short, the current density increases in the protruding portion 10a, and heat is significantly generated in the protruding portion 10 a.
In contrast, in the piezoelectric element of the present invention, the ratio Ps of the area Sa of the protruding portion 10a to the area Sb of the laminated portion 10b is set to 0.02 or more, that is, the area Sa of the protruding portion 10a is increased, so that the current density is suppressed from increasing in the protruding portion 10a, and heat generation in the protruding portion 10a can be suppressed. Further, by setting the length Ya of the side of the protruding portion 10a in contact with the laminated portion 10b to 4mm or more, it is possible to suppress the current density from increasing in the protruding portion 10a and suppress heat generation in the protruding portion 10 a.
On the other hand, if the ratio Ps of the area Sa of the protruding portion 10a to the area Sb of the laminated portion 10b is too large, that is, if the area Sa of the protruding portion 10a is too large, the variation in sound pressure occurs when the plurality of piezoelectric elements 50a of the same specification are manufactured, and particularly, the variation in sound pressure in the high frequency band becomes large, which is a problem. In this regard, it is estimated that when the protrusion 10a is provided, the protrusion 10a vibrates and emits sound when the piezoelectric element 50a is driven, but the sound pressure emitted from the protrusion 10a varies due to variations in the shape of the protrusion 10a, variations in the twisted state, and the like between the plurality of piezoelectric elements. Since the size of the protruding portion 10a is smaller than that of the vibration plate to which the piezoelectric element 50a is attached, the variation in sound pressure emitted from the protruding portion 10a, in particular, the influence in the high frequency band becomes large.
In contrast, in the piezoelectric element of the present invention, the ratio Ps of the area Sa of the protruding portion 10a to the area Sb of the laminated portion 10b is set to 0.3 or less, that is, the area Sa of the protruding portion 10a is reduced, whereby the variation in shape, the variation in distortion state, and the like of the protruding portion 10a can be reduced, and the variation in sound pressure can be reduced.
From the viewpoint of suppressing heat generation of the protruding portion 10a, the length Ya of the side of the protruding portion 10a in contact with the laminated portion 10b is preferably 4mm or more, more preferably 10mm or more, and even more preferably 20mm or more.
From the viewpoint of suppressing heat generation of the protruding portion 10a, the ratio Ps of the area Sa of the protruding portion 10a to the area Sb of the laminated portion 10b is preferably 0.02 or more, more preferably 0.04 or more, and even more preferably 0.06 or more.
From the viewpoint of suppressing the variation in sound pressure, the ratio Ps of the area Sa of the protruding portion 10a to the area Sb of the laminated portion 10b is preferably 0.3 or less, more preferably 0.2 or less, and even more preferably 0.1 or less.
The area Sb of the laminated portion 10b of the piezoelectric element 50a, the area Sa of the protruding portion 10a, and the length Ya of the side where the protruding portion contacts the laminated portion shown in fig. 1 to 3 will be described with reference to fig. 4. Fig. 4 is a plan view of the piezoelectric element 50 a.
The area Sb of the laminated portion 10b and the area Sa of the protruding portion 10a are areas in a plan view. As shown in fig. 4, when the length of the laminated portion 10b in the folding direction in a plan view is Lb and the width in the direction orthogonal to the folding direction is Wb, the area Sb of the laminated portion 10b is lb×wb. If La is the length of the protruding portion 10a in the folding direction and Wa is the width of the protruding portion 10a in the direction perpendicular to the folding direction, the area Sa of the protruding portion 10a is la×wa. In the example shown in fig. 4, the width Wa of the protruding portion 10a is the same as the width Wb of the laminated portion 10 b.
In the example shown in fig. 4, the length Ya of the side where the protruding portion 10a contacts the laminated portion 10b is the same as the width Wa of the protruding portion 10a (the width Wb of the laminated portion 10 b).
In the example shown in fig. 1 to 4, the width Wa of the protruding portion 10a is set to be substantially the same as the width Wb of the laminated portion 10b, but the present invention is not limited thereto.
Fig. 5 is a plan view of another example of the piezoelectric element of the present invention.
The piezoelectric element 50b shown in fig. 5 has a rectangular laminated portion 10b and rectangular protruding portions 10a, and the width Wa of the protruding portions 10a is shorter than the width Wb of the laminated portion 10 b. Accordingly, the length Ya of the side of the protruding portion 10a that contacts the laminated portion 10b is the same as the width Wa of the protruding portion 10 a.
In the example shown in fig. 5, the protruding portion 10a is disposed at the substantially center in the width direction of the laminated portion 10b, but the present invention is not limited to this, and may be disposed at any position in the width direction of the laminated portion 10 b.
In the example shown in fig. 5, the protruding portion 10a is formed in a substantially square shape, but the present invention is not limited to this, and may be rectangular. In this case, the width direction of the protruding portion 10a may be a long side of a rectangle, or the length direction (folding direction) of the protruding portion 10a may be a long side of a rectangle.
The shape of the protruding portion 10a is not limited to a rectangular shape. For example, as in the projection 10a of the piezoelectric element 50c shown in fig. 6, the projection may have a polygonal shape such as a hexagon, or may have various shapes such as a substantially circular shape, a semicircular shape, an elliptical shape, and an irregular shape.
In the example shown in fig. 1 and the like, the protruding portion 10a is configured to protrude in the folding-back direction from the laminated portion 10b, but the present invention is not limited thereto. As in the piezoelectric element 50d shown in fig. 7, the protruding portion 10a may protrude from the laminated portion 10b in the width direction orthogonal to the folding-back direction. As in the example shown in fig. 7, when the protruding portion 10a is rectangular, the length La in the folding-back direction of the protruding portion 10a is equal to the length Ya of the side where the protruding portion contacts the laminated portion.
In the example shown in fig. 1 and the like, the piezoelectric element may have a structure having 1 protruding portion, but the present invention is not limited thereto.
Fig. 8 is a plan view of another example of the piezoelectric element of the present invention.
The piezoelectric element 50e shown in fig. 8 has a rectangular laminated portion 10b and a plurality of rectangular protruding portions 10a arranged along one side of the laminated portion 10 b. Although not shown, a connection portion 40 for connecting the 1 st electrode layer 24 and/or the 2 nd electrode layer 26 to an external electrode is formed in each of the protruding portions 10a. The 1 st protruding portion 10a may be configured such that any one of the 1 st electrode layer 24 and the 2 nd electrode layer 26 is connected to an external electrode, but from the viewpoint of reducing the current density and suppressing heat generation, it is preferable that the 1 st electrode layer 24 and the 2 nd electrode layer 26 are both connected to an external electrode in the 1 st protruding portion 10a. That is, in each of the plurality of protruding portions 10a, it is preferable that both of the 1 st electrode layer 24 and the 2 nd electrode layer 26 are connected to an external electrode.
In the case of a structure having a plurality of protruding portions 10a, the area Sa of the protruding portion 10a is the total area of the plurality of protruding portions 10 a. That is, the ratio of the total area of the plurality of protruding portions 10a to the area of the laminated portion 10b may be in the range of 0.02 to 0.3.
The length Ya of the side of the protruding portion 10a that contacts the laminated portion 10b is the length Ya of the side of each protruding portion 10a that contacts the laminated portion 10b. Accordingly, in each of the protruding portions 10a, the length Ya of the side in contact with the laminated portion 10b may be 4mm or more.
In the case where the piezoelectric element has a structure having a plurality of protruding portions 10a, if the number of protruding portions 10a is excessive, the number of portions where sound is generated increases, and the variation in sound pressure may be increased. Therefore, the number of the protruding portions 10a is preferably 12 or less, more preferably 10 or less.
The piezoelectric element 50a shown in fig. 1 is formed by stacking 5 layers of the film 10, but the present invention is not limited thereto. That is, the piezoelectric element may have 2 to 4 layers of the piezoelectric film 10, or may have 6 or more layers of the piezoelectric film 10.
The following describes the constituent elements of the piezoelectric element of the present invention. In the following description, the piezoelectric elements 50a to 50e are collectively referred to as the piezoelectric element 50 unless distinction is required.
A part of the piezoelectric film 10 is shown enlarged in fig. 9.
The piezoelectric film 10 shown in fig. 9 has: a piezoelectric layer 20 that is a sheet having piezoelectricity; a2 nd electrode layer 26 laminated on one surface of the piezoelectric layer 20; a2 nd protective layer 30 laminated on the surface of the 2 nd electrode layer 26 opposite to the piezoelectric layer 20; a1 st electrode layer 24 laminated on the other surface of the piezoelectric layer 20; the 1 st protective layer 28 is laminated on the surface of the 1 st electrode layer 24 opposite to the piezoelectric layer 20. That is, the piezoelectric film 10 has a structure in which the piezoelectric layer 20 is sandwiched between electrode layers, and a protective layer is laminated on a surface of the electrode layers, which is not in contact with the piezoelectric layer.
In the present invention, various known piezoelectric layers can be used for the piezoelectric layer 20.
In the present invention, as schematically shown in fig. 9, the piezoelectric layer 20 is preferably a polymer composite piezoelectric body including piezoelectric particles 36 in a matrix 34 including a polymer material.
As a material of the matrix 34 (matrix binder) of the polymer composite piezoelectric body constituting the piezoelectric layer 20, a polymer material having viscoelasticity at normal temperature is preferably used. In the present specification, "normal temperature" means a temperature range of about 0 to 50 ℃.
Among them, the polymer composite piezoelectric body (piezoelectric layer 20) preferably has the following requirements.
(I) Flexibility of
For example, when a portable article such as a newspaper or a magazine is held in a gently curved state like a document, a relatively slow and large bending deformation of several Hz or less is continuously applied from the outside. At this time, when the polymer composite piezoelectric body is hard, a corresponding large bending stress is generated, and cracks are generated at the interface between the polymer matrix and the piezoelectric body particles, and as a result, the breakage may occur. Therefore, the polymer composite piezoelectric body is required to have appropriate flexibility. Further, if strain energy can be diffused as heat to the outside, stress can be relaxed. Therefore, the loss tangent of the polymer composite piezoelectric body is required to be appropriately large.
As described above, a flexible polymer composite piezoelectric body used as an exciter is required to operate relatively hard against vibrations of 20Hz to 20kHz and to operate relatively soft against vibrations of several Hz or less. In addition, the loss tangent of the polymer composite piezoelectric body is required to be appropriately large for vibrations at all frequencies of 20kHz or less.
Further, it is preferable that the spring constant is easily adjusted by laminating the adhesive materials (diaphragm) according to the rigidity (hardness, stiffness, spring constant), and in this case, the thinner the adhesive layer 104 is, the higher the energy efficiency can be.
In general, a polymer solid has a viscoelastic relaxation mechanism, and a large-scale molecular motion is observed as a decrease (relaxation) in storage modulus (young's modulus) or an maximization (absorption) in loss modulus with an increase in temperature or a decrease in frequency. Among them, alleviation caused by Micro Brownian (Micro Brownian) motion of molecular chains of amorphous regions is called primary dispersion, and a very large alleviation phenomenon can be observed. The temperature at which this primary dispersion occurs is the glass transition point (Tg), and the viscoelastic mitigation mechanism appears most pronounced.
In the polymer composite piezoelectric body (piezoelectric layer 20), a polymer material having a glass transition point at normal temperature, in other words, a polymer material having viscoelasticity at normal temperature is used in a matrix, whereby a polymer composite piezoelectric body which operates relatively hard against vibrations of 20Hz to 20kHz and operates relatively soft against slow vibrations of several Hz or less is realized. In particular, in order to properly exhibit such an action, a polymer material having a glass transition point at a frequency of 1Hz at normal temperature, that is, at 0 to 50 ℃ is preferably used in the matrix of the polymer composite piezoelectric body.
As the polymer material having viscoelasticity at normal temperature, various known polymer materials can be used. It is preferable to use a polymer material having a maximum value of Tan delta at a frequency of 1Hz, which is obtained by a dynamic viscoelasticity test at normal temperature, that is, at 0 to 50 ℃.
Accordingly, when the polymer composite piezoelectric body is gently bent by an external force, stress concentration at the interface between the polymer matrix and the piezoelectric body particles in the maximum bending moment portion is relaxed, and high flexibility can be expected.
The storage modulus (E') of the polymer material having viscoelasticity at normal temperature at a frequency of 1Hz, which is measured based on dynamic viscoelasticity, is preferably 100MPa or more at 0℃and 10MPa or less at 50 ℃.
This can reduce bending moment generated when the polymer composite piezoelectric body is slowly bent by an external force, and can operate harder against acoustic vibrations of 20Hz to 20 kHz.
It is more preferable that the relative dielectric constant of the polymer material having viscoelasticity at ordinary temperature is 10 or more at 25 ℃. Thus, when a voltage is applied to the polymer composite piezoelectric body, a higher electric field is applied to the piezoelectric particles in the matrix, and thus a larger deformation amount can be expected.
However, on the other hand, if it is considered to ensure good moisture resistance or the like, it is also preferable that the relative dielectric constant of the polymer material is 10 or less at 25 ℃.
Examples of the polymer material having viscoelasticity at ordinary temperature satisfying these conditions include cyanoethylated polyvinyl alcohol (cyanoethylated PVA), polyvinyl acetate, polyvinylidene chloride acrylonitrile, polystyrene-vinyl polyisoprene block copolymer, polyvinyl methyl ketone, and polybutylmethacrylate. Further, commercial products such as HYBRAR5127 (KURARAY co., LTD) can be suitably used as the polymer material. Among them, as the polymer material, a material having cyanoethyl groups is preferably used, and cyanoethylated PVA is particularly preferably used.
As the polymer material having viscoelasticity at normal temperature, a polymer material having cyanoethyl group is preferably used, and cyanoethylated PVA is particularly preferably used. That is, in the present invention, the piezoelectric layer 20 preferably uses a polymer material having cyanoethyl groups as the substrate 34, and particularly preferably uses cyanoethylated PVA.
In the following description, the above polymer materials represented by cyanoethylated PVA are also collectively referred to as "polymer materials having viscoelasticity at ordinary temperature".
In addition, only 1 kind of these polymer materials having viscoelasticity at normal temperature may be used, or a plurality of kinds may be used in combination (mixture).
The substrate 34 using these polymer materials having viscoelasticity at ordinary temperature may be made of a plurality of polymer materials in combination as needed.
That is, in order to adjust the dielectric characteristics, mechanical characteristics, and the like, other dielectric polymer materials may be added to the substrate 34 as needed in addition to the viscoelastic material such as cyanoethylated PVA.
Examples of the dielectric polymer material that can be added include fluorine-based polymers such as polyvinylidene fluoride, vinylidene fluoride-tetrafluoroethylene copolymer, vinylidene fluoride-trifluoroethylene copolymer, polyvinylidene fluoride-trifluoroethylene copolymer, and polyvinylidene fluoride-tetrafluoroethylene copolymer, polymers having cyano groups or cyano groups such as vinylidene fluoride-vinyl ester copolymer, cyanoethyl cellulose, cyanoethyl hydroxy sucrose, cyanoethyl hydroxy cellulose, cyanoethyl hydroxy fullerene, cyanoethyl methacrylate, cyanoethyl acrylate, cyanoethyl hydroxyethyl cellulose, cyanoethyl amylose, cyanoethyl hydroxypropyl cellulose, cyanoethyl dihydroxypropyl cellulose, cyanoethyl hydroxypropyl amylose, cyanoethyl polyacrylamide, cyanoethyl polyethyl polyacrylate, cyanoethyl fullerene, cyanoethyl polyhydroxymethylene, cyanoethyl glycidyl fullerene, cyanoethyl sucrose, cyanoethyl sorbitol, and synthetic rubbers such as nitrile rubber and chloroprene rubber.
Among them, a polymer material having cyanoethyl groups can be preferably used.
The number of these dielectric polymer materials is not limited to 1, and a plurality of these dielectric polymer materials may be added to the substrate 34 of the piezoelectric layer 20.
In addition, in order to adjust the glass transition point Tg, a thermoplastic resin such as a vinyl chloride resin, polyethylene, polystyrene, methacrylic resin, polybutylene, and isobutylene, and a thermosetting resin such as a phenol resin, a urea resin, a melamine resin, an alkyd resin, and mica may be added to the matrix 34 in addition to the dielectric polymer material.
Further, for the purpose of improving the adhesiveness, a tackifier such as rosin ester, rosin, terpenes, terpene phenol, and petroleum resin may be added.
The amount of the material other than the material having viscoelasticity such as cyanoethylated PVA added to the matrix 34 of the piezoelectric layer 20 is not particularly limited, but is preferably 30 mass% or less based on the amount of the material in the matrix 34.
Accordingly, since the characteristics of the polymer material to be added can be exhibited without impairing the viscoelastic relaxation mechanism in the matrix 34, preferable results can be obtained in terms of improvement of dielectric constant, heat resistance, adhesion to the piezoelectric particles 36 and the electrode layer, and the like.
The piezoelectric layer 20 is a layer made of a polymer composite piezoelectric material including the piezoelectric particles 36 in the matrix 34. The piezoelectric particles 36 are dispersed in the matrix 34. Preferably, the piezoelectric particles 36 are uniformly (substantially uniformly) dispersed in the matrix 34.
The piezoelectric particles 36 are composed of ceramic particles having a perovskite-type or wurtzite-type crystal structure.
Examples of ceramic particles constituting the piezoelectric particles 36 include lead zirconate titanate (PZT), lead lanthanum zirconate titanate (PLZT), barium titanate (BaTiO 3), zinc oxide (ZnO), and a solid solution (BFBT) of barium titanate and bismuth ferrite (BiFe 3).
The particle size of the piezoelectric particles 36 is not limited, and may be appropriately selected according to the size of the piezoelectric film 10, the application of the piezoelectric element 50, and the like. The particle diameter of the piezoelectric particles 36 is preferably 1 to 10. Mu.m.
By setting the particle diameter of the piezoelectric particles 36 within this range, preferable results can be obtained in terms of the piezoelectric film 10 being able to achieve both high-voltage characteristics and flexibility.
The piezoelectric particles 36 in the piezoelectric layer 20 may be uniformly and regularly dispersed in the matrix 34, or may be irregularly dispersed in the matrix 34 as long as they are uniformly dispersed.
In the piezoelectric film 10, the amount ratio of the matrix 34 and the piezoelectric particles 36 in the piezoelectric layer 20 is not limited, and may be appropriately set according to the size and thickness of the piezoelectric film 10 in the plane direction, the use of the piezoelectric element 50, the characteristics required for the piezoelectric element 50, and the like.
The volume fraction of the piezoelectric particles 36 in the piezoelectric layer 20 is preferably 30 to 80%, more preferably 50% or more, and thus, more preferably 50 to 80%.
When the amount ratio of the matrix 34 to the piezoelectric particles 36 is within the above range, preferable results can be obtained in terms of both high-voltage characteristics and flexibility.
In the piezoelectric film 10, the thickness of the piezoelectric layer 20 is not particularly limited, and may be appropriately set according to the application of the piezoelectric element 50, the number of layers of the piezoelectric film in the piezoelectric element 50, the characteristics required in the piezoelectric film 10, and the like.
The thicker the piezoelectric layer 20 is, the more advantageous the rigidity such as the rigidity of the so-called sheet, but the larger the voltage (potential difference) required to expand and contract the piezoelectric film 10 by the same amount.
The thickness of the piezoelectric layer 20 is preferably 10 to 300. Mu.m, more preferably 20 to 200. Mu.m, and still more preferably 30 to 150. Mu.m.
By setting the thickness of the piezoelectric layer 20 within the above range, preferable results can be obtained in terms of both securing rigidity and appropriate flexibility.
The piezoelectric layer 20 is preferably subjected to polarization (polarization) in the thickness direction.
In the present invention, the piezoelectric layer 20 is not limited to the polymer composite piezoelectric body including the piezoelectric particles 36 in the matrix 34 made of the polymer material having viscoelasticity at normal temperature such as cyanoethylated PVA as described above.
That is, in the piezoelectric film 10 of the present invention, various known piezoelectric layers can be used as the piezoelectric layer.
As an example, a polymer composite piezoelectric material including the same piezoelectric particles 36 in a matrix including the dielectric polymer material such as polyvinylidene fluoride, vinylidene chloride-tetrafluoroethylene copolymer, and vinylidene chloride-trifluoroethylene copolymer, a piezoelectric layer made of polyvinylidene fluoride, a piezoelectric layer made of a fluororesin other than polyvinylidene fluoride, a piezoelectric layer formed of a thin film made of poly-L-lactic acid, and a thin film made of poly-D-lactic acid, and the like can be used.
However, as described above, from the viewpoint of being able to operate relatively hard for vibrations of 20Hz to 20kHz, being able to operate relatively soft for vibrations of several Hz or less, and being able to obtain excellent acoustic characteristics, excellent flexibility, and the like, it is preferable to use the above-described polymer composite piezoelectric body including the piezoelectric particles 36 in the matrix 34 made of a polymer material having viscoelasticity at normal temperature, such as cyanoethylated PVA.
As shown in fig. 9, the piezoelectric film 10 has a structure in which the 2 nd electrode layer 26 is provided on one surface of the piezoelectric layer 20, the 2 nd protective layer 30 is provided thereon, the 1 st electrode layer 24 is provided on the other surface of the piezoelectric layer 20, and the 1 st protective layer 28 is provided thereon. Wherein the 1 st electrode layer 24 and the 2 nd electrode layer 26 form an electrode pair.
That is, the piezoelectric film 10 has a structure in which the piezoelectric layer 20 is sandwiched between the electrode pairs, namely, the 2 nd electrode layer 26 and the 1 st electrode layer 24, and the laminate is sandwiched between the 2 nd protective layer 30 and the 1 st protective layer 28.
In this way, in the piezoelectric film 10, the region sandwiched between the 2 nd electrode layer 26 and the 1 st electrode layer 24 expands and contracts according to the applied voltage.
The 2 nd electrode layer 26 and the 2 nd protective layer 30, and the 1 st electrode layer 24 and the 1 st protective layer 28 are added for convenience of explanation of the piezoelectric film 10. Therefore, the 1 st and the 2 nd of the present invention have no technical significance and are not related to the actual use state.
In the present invention, the piezoelectric film 10 may have, for example, an adhesive layer for adhering the electrode layer and the piezoelectric layer 20 and an adhesive layer for adhering the electrode layer and the protective layer, in addition to these layers.
The adhesive may be an adhesive or an adhesive. The adhesive may be preferably the same as the substrate 34, which is a polymer material from which the piezoelectric particles 36 are removed from the piezoelectric layer 20. The adhesive layer may be provided on both the 1 st electrode layer 24 side and the 2 nd electrode layer 26 side, or may be provided on only one of the 1 st electrode layer 24 side and the 2 nd electrode layer 26 side.
In the piezoelectric film 10, the 2 nd protective layer 30 and the 1 st protective layer 28 cover the 1 st electrode layer 24 and the 2 nd electrode layer 26, and also function to impart appropriate rigidity and mechanical strength to the piezoelectric layer 20. That is, in the piezoelectric film 10, the piezoelectric layer 20 composed of the matrix 34 and the piezoelectric particles 36 exhibits very excellent flexibility against slow bending deformation, but may be insufficient in rigidity or mechanical strength depending on the application. The 2 nd protective layer 30 and the 1 st protective layer 28 are provided in the piezoelectric film 10 to compensate for this.
The 1 st protective layer 28 and the 2 nd protective layer 30 are identical in structure with only different arrangement positions. Therefore, in the following description, the two members are also collectively referred to as the protective layers without the need to distinguish between the 1 st protective layer 28 and the 2 nd protective layer 30.
The 2 nd and 1 st protective layers 30 and 28 are not limited, and various kinds of sheet-like materials can be used, and as an example, various kinds of resin films are preferably exemplified.
Among them, for reasons of excellent mechanical properties and heat resistance, resin films composed of polyethylene terephthalate (PET), polypropylene (PP), polystyrene (PS), polycarbonate (PC), polyphenylene Sulfide (PPs), polymethyl methacrylate (PMMA), polyetherimide (PEI), polyimide (PI), polyethylene naphthalate (PEN), triacetyl cellulose (TAC), a cyclic olefin resin, and the like are preferably used.
The thickness of the 2 nd and 1 st protective layers 30 and 28 is not limited. The thicknesses of the 2 nd and 1 st protective layers 30 and 28 are substantially the same, but may be different.
If the rigidity of the 2 nd and 1 st protective layers 30 and 28 is too high, the flexibility is impaired as well as the expansion and contraction of the piezoelectric layer 20 is restricted. Therefore, in addition to the case where mechanical strength and good handleability as a sheet are required, the thinner the 2 nd protective layer 30 and the 1 st protective layer 28 are, the more advantageous.
In the piezoelectric film 10, if the thickness of the 2 nd protective layer 30 and the 1 st protective layer 28 is 2 times or less the thickness of the piezoelectric layer 20, preferable results can be obtained in terms of both securing rigidity and appropriate flexibility.
For example, when the thickness of the piezoelectric layer 20 is 50 μm and the 2 nd and 1 st protective layers 30 and 28 are made of PET, the thickness of the 2 nd and 1 st protective layers 30 and 28 is preferably 100 μm or less, more preferably 50 μm or less, and still more preferably 25 μm or less.
In the piezoelectric film 10, the 2 nd electrode layer 26 is formed between the piezoelectric layer 20 and the 2 nd protective layer 30, and the 1 st electrode layer 24 is formed between the piezoelectric layer 20 and the 1 st protective layer 28. The 2 nd electrode layer 26 and the 1 st electrode layer 24 are provided for applying a voltage to the piezoelectric layer 20 (piezoelectric film 10).
The 1 st electrode layer 24 and the 2 nd electrode layer 26 are substantially identical except for their positions. Therefore, in the following description, the two members are also collectively referred to as electrode layers without the need to distinguish between the 1 st electrode layer 24 and the 2 nd electrode layer 26.
In the present invention, the materials for forming the 2 nd electrode layer 26 and the 1 st electrode layer 24 are not limited, and various electric conductors can be used. Specifically, metals such as carbon, palladium, iron, tin, aluminum, nickel, platinum, gold, silver, copper, titanium, chromium, and molybdenum, alloys thereof, laminates and composites of these metals and alloys, indium tin oxide, and the like are exemplified. Or also exemplified are conductive polymers such as PEDOT/PPS (polyethylene dioxythiophene-polystyrene sulfonic acid). Among them, copper, aluminum, gold, silver, platinum, and indium tin oxide are preferably exemplified as the 2 nd electrode layer 26 and the 1 st electrode layer 24. Among them, copper is more preferable from the viewpoints of conductivity, cost, flexibility, and the like.
The method for forming the 2 nd electrode layer 26 and the 1 st electrode layer 24 is not limited, and various known methods such as a vapor deposition method (vacuum film forming method) by vacuum vapor deposition, sputtering, and the like, a film forming method by electroplating, and a method of adhering a foil formed of the above materials can be used.
Among these, for reasons such as ensuring flexibility of the piezoelectric film 10, it is particularly preferable to use thin films of copper, aluminum, or the like formed by vacuum deposition as the 2 nd electrode layer 26 and the 1 st electrode layer 24. Among them, a thin film of copper formed by vacuum evaporation is particularly preferably used.
The thicknesses of the 2 nd electrode layer 26 and the 1 st electrode layer 24 are not limited. The thicknesses of the 2 nd electrode layer 26 and the 1 st electrode layer 24 are substantially the same, but may be different.
However, if the rigidity of the 2 nd electrode layer 26 and the 1 st electrode layer 24 is too high, the flexibility is impaired as well as the expansion and contraction of the piezoelectric layer 20 is restricted, similarly to the 2 nd protective layer 30 and the 1 st protective layer 28 described above. Therefore, the thinner the 2 nd electrode layer 26 and the 1 st electrode layer 24 are, the more advantageous as long as the resistance does not become excessively high.
In the piezoelectric film 10, it is preferable that the product of the thickness of the 2 nd electrode layer 26 and the 1 st electrode layer 24 and the young's modulus is lower than the product of the thickness of the 2 nd protective layer 30 and the 1 st protective layer 28, since flexibility is not seriously impaired.
For example, in the case of a combination in which the 2 nd protective layer 30 and the 1 st protective layer 28 are made of PET (Young's modulus: about 6.2 GPa) and the 2 nd electrode layer 26 and the 1 st electrode layer 24 are made of copper (Young's modulus: about 130 GPa), the thickness of the 2 nd protective layer 30 and the 1 st protective layer 28 is preferably 1.2 μm or less, more preferably 0.3 μm or less, and among these, 0.1 μm or less is preferable.
As described above, the piezoelectric film 10 has a structure in which the piezoelectric layer 20 in which the piezoelectric particles 36 are dispersed in the matrix 34 containing the polymer material is sandwiched between the 2 nd electrode layer 26 and the 1 st electrode layer 24, and the laminate is sandwiched between the 2 nd protective layer 30 and the 1 st protective layer 28.
In such a piezoelectric film 10, the maximum value of the loss tangent (Tan δ) at the frequency of 1Hz, which is obtained by dynamic viscoelasticity measurement, is preferably present at normal temperature, and more preferably, the maximum value of 0.1 or more is present at normal temperature.
Accordingly, even when the piezoelectric film 10 receives relatively slow and large bending deformation of several Hz or less from the outside, strain energy can be efficiently diffused to the outside as heat, and thus occurrence of cracks at the interface between the polymer matrix and the piezoelectric particles can be prevented.
In the piezoelectric film 10, the storage modulus (E') at a frequency of 1Hz, which is measured based on dynamic viscoelasticity, is preferably 10 to 30GPa at 0℃and 1 to 10GPa at 50 ℃. The conditions are also similar to those of the piezoelectric layer 20.
Thus, the piezoelectric film 10 can have a large frequency dispersion in the storage modulus (E') at normal temperature. That is, the vibration damper can operate relatively hard against vibrations of 20Hz to 20kHz and relatively soft against vibrations of several Hz or less.
In addition, in the piezoelectric film 10, the product of the thickness and the storage modulus (E') at a frequency of 1Hz, which is measured based on dynamic viscoelasticity, is preferably 1.0X10 5～2.0×106 N/m at 0℃and 1.0X10 5～1.0×106 N/m at 50 ℃. The conditions are also similar to those of the piezoelectric layer 20.
Thus, the piezoelectric film 10 can have appropriate rigidity and mechanical strength without impairing flexibility and acoustic characteristics.
Further, in the piezoelectric film 10, the loss tangent (Tan δ) at a frequency of 1kHz at 25 ℃ is preferably 0.05 or more in the main curve obtained from dynamic viscoelasticity measurement. The conditions are also similar to those of the piezoelectric layer 20.
Thus, the frequency characteristic of the speaker using the piezoelectric film 10 is smoothed, and the amount of change in sound quality when the lowest resonance frequency f 0 changes with a change in curvature of the speaker can be reduced.
In the present invention, the storage modulus (young's modulus) and loss tangent of the piezoelectric film 10, the piezoelectric layer 20, and the like may be measured by a known method. As an example, measurement may be performed using a dynamic viscoelasticity measurement device DMS6100 manufactured by SII Nano Technology inc.
As an example of the measurement conditions, the following are illustrated respectively: the measurement frequency is 0.1 Hz-20 Hz (0.1 Hz, 0.2Hz, 0.5Hz, 1Hz, 2Hz, 5Hz, 10Hz and 20 Hz), the measurement temperature is-50-150 ℃, the heating rate is 2 ℃/min (in nitrogen atmosphere), the sample size is 40mm multiplied by 10mm (including the splint region), and the space between chucks is 20mm.
In the piezoelectric element 50, a power source (external power source) for applying a driving voltage for expanding and contracting the piezoelectric film 10, that is, supplying driving power, is connected to the 2nd electrode layer 26 and the 1 st electrode layer 24 of the piezoelectric film 10.
The power supply is not limited, and may be a direct current power supply or an alternating current power supply. The driving voltage may be appropriately set according to the thickness of the piezoelectric layer 20 of the piezoelectric film 10, the material to be formed, and the like, so that the piezoelectric film 10 can be driven appropriately.
As described above, when the electrodes are extracted from the 2 nd electrode layer 26 and the 1 st electrode layer 24, the extraction is performed at the protruding portion 10 a. The method for extracting the electrodes from the 2 nd electrode layer 26 and the 1 st electrode layer 24 is not limited, and various known methods can be used.
As an example, a method of connecting a conductor such as copper foil to the 2 nd electrode layer 26 and the 1 st electrode layer 24 to draw out an electrode to the outside, a method of forming a through hole in the 2 nd protective layer 30 and the 1 st protective layer 28 by laser or the like, and filling a conductive material into the through hole to draw out an electrode to the outside, and the like are illustrated.
Examples of preferred electrode extraction methods include the method described in Japanese patent application laid-open No. 2014-209724 and the method described in Japanese patent application laid-open No. 2016-015354.
An example of a method for producing the piezoelectric film 10 will be described below with reference to fig. 10 to 12.
First, as shown in fig. 10, a sheet 12a having the 2 nd electrode layer 26 formed on the surface of the 2 nd protective layer 30 is prepared. Further, a sheet 12c schematically shown in fig. 12, in which the 1 st electrode layer 24 is formed on the surface of the 1 st protective layer 28, was prepared.
The sheet 12a may be produced by forming a copper film or the like as the 2 nd electrode layer 26 on the surface of the 2 nd protective layer 30 by vacuum deposition, sputtering, plating, or the like. Similarly, the sheet 12c may be produced by forming a copper film or the like as the 1 st electrode layer 28 on the surface of the 1 st protective layer 24 by vacuum deposition, sputtering, plating, or the like.
Alternatively, a commercially available sheet in which a copper film or the like is formed on the protective layer may be used as the sheet 12a and/or the sheet 12c.
The sheet 12a and the sheet 12c may be the same or different.
In addition, when the protective layer is extremely thin and the operability is poor, etc., a protective layer with a separator (temporary support) may be used as needed. Further, PET having a thickness of 25 to 100 μm or the like can be used as the separator. The separator may be removed after the thermocompression bonding of the electrode layer and the protective layer.
Next, as shown in fig. 11, the coating material (coating composition) to be the piezoelectric layer 20 is applied to the 2 nd electrode layer 26 of the sheet 12a, and then cured to form the piezoelectric layer 20. Thus, the piezoelectric laminate 12b in which the sheet 12a and the piezoelectric layer 20 are laminated is produced.
The formation of the piezoelectric layer 20 can utilize various methods depending on the material forming the piezoelectric layer 20.
As an example, first, the above-mentioned polymer material such as cyanoethylated PVA is dissolved in an organic solvent, and piezoelectric particles 36 such as PZT particles are added thereto, followed by stirring to prepare a paint.
The organic solvent is not limited, and various organic solvents such as Dimethylformamide (DMF), methyl Ethyl Ketone (MEK), and cyclohexanone can be used.
After the sheet 12a is prepared and the dope is prepared, the dope is cast (coated) on the sheet 12a, and the organic solvent is evaporated and dried. As a result, as shown in fig. 11, a piezoelectric laminate 12b having the 2 nd electrode layer 26 on the 2 nd protective layer 30 and the piezoelectric layer 20 laminated on the 2 nd electrode layer 26 was produced.
The method of casting the paint is not limited, and any known method (coating apparatus) such as a bar coater, a bevel blade coater (slidecoater), and a coater blade (doctorknife) can be used.
Alternatively, if the polymer material is a substance that can be melted by heating, a melt in which the piezoelectric particles 36 are added can be produced by melting the polymer material by heating, and the piezoelectric laminate 12b shown in fig. 11 can be produced by extruding the melt in a sheet form onto the sheet 12a shown in fig. 10 by extrusion molding or the like and cooling the extruded melt.
As described above, in addition to the polymer material having viscoelasticity at normal temperature, a polymer piezoelectric material such as PVDF may be added to the substrate 34 in the piezoelectric layer 20.
When these polymer piezoelectric materials are added to the substrate 34, the polymer piezoelectric materials added to the paint may be dissolved. Alternatively, the polymer piezoelectric material to be added may be added to the polymer material which is melted by heating and has viscoelasticity at ordinary temperature, and the polymer piezoelectric material may be melted by heating.
After the piezoelectric layer 20 is formed, a rolling treatment may be performed as needed. The rolling treatment may be performed 1 time or a plurality of times.
As is well known, the rolling treatment is a treatment of heating a surface to be treated by hot pressing, a heating roller, or the like, and simultaneously pressing to perform planarization or the like.
Next, polarization treatment (polarization) is performed on the piezoelectric layer 20 of the piezoelectric laminate 12b having the 2 nd electrode layer 26 on the 2 nd protective layer 30 and the piezoelectric layer 20 formed on the 2 nd electrode layer 26. The polarization treatment of the piezoelectric layer 20 may be performed before the rolling treatment, but is preferably performed after the rolling treatment is performed.
The method of polarizing the piezoelectric layer 20 is not limited, and a known method can be used. For example, electric field polarization in which a direct electric field is directly applied to an object to be subjected to polarization processing is exemplified. In the case of performing electric field polarization, the 1 st electrode layer 24 may be formed before the polarization treatment, and the electric field polarization treatment may be performed using the 1 st electrode layer 24 and the 2 nd electrode layer 26.
In the piezoelectric film 10 of the present invention, the polarization treatment is preferably performed not in the plane direction of the piezoelectric layer 20 but in the thickness direction.
Next, as shown in fig. 12, the 1 st electrode layer 24 is laminated on the piezoelectric layer 20 side of the piezoelectric laminate 12b subjected to the polarization treatment so as to face the piezoelectric layer 20, whereby a sheet 12c prepared in advance is laminated.
Further, the piezoelectric film 10 shown in fig. 9 is produced by sandwiching the laminate between the 1 st protective layer 28 and the 2 nd protective layer 30, and thermally bonding the piezoelectric laminate 12b to the sheet 12c by using a hot press device, a heating roller, or the like.
Or the piezoelectric laminate 12b and the sheet 12c are bonded (preferably further pressure-bonded) with an adhesive to produce the piezoelectric film 10.
The piezoelectric film 10 may be manufactured by cutting a sheet-like sheet 12a, a sheet 12c, or the like, or may be manufactured by Roll-to-Roll (Roll to Roll).
The piezoelectric film thus produced may be cut into a desired shape according to various applications.
The piezoelectric film 10 manufactured in this way is polarized only in the thickness direction, not in the plane direction, and a high piezoelectric characteristic can be obtained even if the stretching treatment is not performed after the polarization treatment. Therefore, the piezoelectric film 10 does not have in-plane anisotropy in piezoelectric characteristics, and expands and contracts isotropically in all directions in the plane direction when a driving voltage is applied.
In the adhesive layer 14 for attaching the piezoelectric films to each other, as long as the adjacent piezoelectric films 10 can be attached, various known materials can be used, and the same materials as the adhesive layer 104 for attaching the vibration plate and the piezoelectric element described later can be used.
[ Electroacoustic transducer ]
The electroacoustic transducer of the invention is that
An electroacoustic transducer formed by adhering the piezoelectric element to a vibration plate.
Fig. 13 is a diagram schematically showing an example of the electroacoustic transducer of the present invention having the piezoelectric element of the present invention.
The electroacoustic transducer 100 shown in fig. 13 has the piezoelectric element 50a described above, the vibration plate 102, and the adhesive layer 104 that adheres the piezoelectric element 50a to the vibration plate 102. In the example shown in fig. 13, the lamination portion 9 of the surface of the piezoelectric element 50a on the side having the protruding portion 10a is preferably adhered to the vibration plate 102.
In this electroacoustic transducer 100, the piezoelectric film 10 expands and contracts in the planar direction by applying a driving voltage to the piezoelectric film 10 of the piezoelectric element 50a, and the piezoelectric element 50a expands and contracts in the planar direction by the expansion and contraction of the piezoelectric film 10.
As a result of the expansion and contraction of the piezoelectric element 50a in the plane direction, the diaphragm 102 bends, and as a result, the diaphragm 102 vibrates in the thickness direction. By this vibration in the thickness direction, the vibration plate 102 emits sound. The vibration plate 102 vibrates according to the magnitude of the driving voltage applied to the piezoelectric film 10, and emits sound corresponding to the driving voltage applied to the piezoelectric film 10.
Preferably, the vibration plate 102 is a flexible member. In the present invention, the term "flexible" means capable of bending and flexing as commonly interpreted as having flexibility, and specifically, capable of bending and stretching without breaking or damaging.
The diaphragm 102 is not limited as long as it has flexibility, and various kinds of sheet-like objects (plate-like objects, films) can be used.
Examples of the resin film include polyethylene terephthalate (PET), polypropylene (PP), polystyrene (PS), polycarbonate (PC), polyphenylene Sulfide (PPs), polymethyl methacrylate (PMMA), polyetherimide (PEI), polyimide (PI), polyethylene naphthalate (PEN), triacetyl cellulose (TAC), and a cyclic olefin resin, foamed plastics including foamed polystyrene, foamed styrene, and foamed polyethylene, and various corrugated paper materials obtained by adhering one or both sides of a corrugated cardboard to other cardboard.
In addition, as long as the electroacoustic transducer 100 has flexibility, a display device such as an Organic LIGHT EMITTING Diode (OLED) display, a liquid crystal display, a micro LED (LIGHT EMITTING Diode) display, or an inorganic electroluminescent Diode display can be appropriately used as the vibration plate 102.
In the electroacoustic transducer 100, the vibration plate 102 and the piezoelectric element 50 are bonded by the bonding layer 104.
As long as the vibration plate 102 and the piezoelectric element 50 can be bonded, various known materials can be used for the bonding layer 104.
Accordingly, the adhesive layer 104 may be a layer made of an adhesive that has fluidity at the time of bonding and becomes solid after that, may be a layer made of an adhesive that is soft solid in a gel state (rubber-like) at the time of bonding and also remains in a gel state after that, or may be a layer made of a material having characteristics of both an adhesive and an adhesive.
In the electroacoustic transducer 100, the piezoelectric element 50 is stretched to bend the vibration plate 102, thereby vibrating the same to generate sound. Therefore, in the electroacoustic transducer 100, it is preferable that the expansion and contraction of the piezoelectric element 50 is directly transmitted to the vibration plate 102. If a viscous substance such as a vibration-reducing substance exists between the vibration plate 102 and the piezoelectric element 50, the transmission efficiency of the expansion and contraction energy of the piezoelectric element 50 to the vibration plate 102 is reduced, and the driving efficiency of the electroacoustic transducer 100 is reduced.
In view of this, the adhesive layer 104 is preferably an adhesive layer composed of an adhesive, and the adhesive layer can obtain a solid and hard adhesive layer 104 as compared with an adhesive layer composed of an adhesive. More preferred examples of the adhesive layer 104 include adhesive layers made of thermoplastic adhesives such as polyester adhesives and styrene-butadiene rubber (SBR) adhesives.
Bonding is useful when a high bonding temperature is required, unlike bonding. In addition, thermoplastic type adhesives are preferred because they combine "relatively low temperature, short time, and strong adhesion".
The thickness of the adhesive layer 104 is not limited as long as a thickness capable of obtaining a sufficient adhesive force (adhesive force, cohesive force) is appropriately set according to the material of the adhesive layer 104.
In the electroacoustic transducer 100, the thinner the adhesive layer 104 is, the more the transmission effect of the expansion and contraction energy (vibration energy) transmitted to the piezoelectric element 50 of the vibration plate 102 is improved, and the energy efficiency can be improved. In addition, if the adhesive layer 104 is thick and has high rigidity, expansion and contraction of the piezoelectric element 50 may be restricted.
In view of this, the adhesive layer 104 is preferably thin. Specifically, the thickness of the adhesive layer 104 is preferably 0.1 to 50 μm, more preferably 0.1 to 30 μm, and even more preferably 0.1 to 10 μm in terms of the thickness after adhesion.
In addition, in the electroacoustic transducer 100, the adhesive layer 104 is a layer provided as a preferable embodiment, and is not an essential constituent element.
Therefore, even if the electroacoustic transducer 100 does not include the adhesive layer 104, the vibration plate 102 and the piezoelectric element 50 may be fixed using a known pressure bonding mechanism, fastening mechanism, fixing mechanism, or the like. For example, in the case where the piezoelectric element 50 is rectangular in shape in plan view, the electroacoustic transducer may be configured by fastening four corners with members such as bolts and nuts, or may be configured by fastening four corners and a center portion with members such as bolts and nuts.
However, at this time, when the driving voltage is applied from the power supply, the piezoelectric element 50 expands and contracts independently from the vibration plate 102, and in some cases, only the piezoelectric element 50 bends and the expansion and contraction of the piezoelectric element 50 cannot be transmitted to the vibration plate 102. In this way, when the piezoelectric element 50 expands and contracts independently of the diaphragm 102, the vibration efficiency of the diaphragm 102 by the piezoelectric element 50 decreases. There is a possibility that the vibration plate 102 cannot be sufficiently vibrated.
In view of this, as shown in fig. 13, the vibration plate 102 and the piezoelectric element 50 are preferably bonded by the bonding layer 104.
Wherein, as described above, the piezoelectric layer 20 contains the piezoelectric particles 36 in the matrix 34. The 2 nd electrode layer 26 and the 1 st electrode layer 24 are provided so as to sandwich the piezoelectric layer 20 in the thickness direction.
When a voltage is applied to the 2 nd electrode layer 26 and the 1 st electrode layer 24 of the piezoelectric film 10 having such a piezoelectric layer 20, the piezoelectric particles 36 expand and contract in the polarization direction according to the applied voltage. As a result, the piezoelectric film 10 (piezoelectric layer 20) contracts in the thickness direction. Meanwhile, the piezoelectric film 10 also stretches in the in-plane direction due to the poisson's ratio. The expansion and contraction is about 0.01 to 0.1%.
As described above, the thickness of the piezoelectric layer 20 is preferably about 10 to 300 μm. Therefore, the maximum expansion and contraction in the thickness direction is only about 0.3 μm, which is very small.
In contrast, the piezoelectric film 10, that is, the piezoelectric layer 20, has a dimension significantly larger than the thickness in the planar direction. Therefore, for example, when the length of the piezoelectric film 10 is 20cm, the piezoelectric film 10 stretches and contracts approximately 0.2mm at maximum by applying a voltage.
The vibration plate 102 is attached to the piezoelectric film 10 through the adhesive layer 104. Accordingly, the diaphragm 102 is bent by the expansion and contraction of the piezoelectric film 10, and as a result, the diaphragm 102 vibrates in the thickness direction.
By this vibration in the thickness direction, the vibration plate 102 emits sound. That is, the vibration plate 102 vibrates according to the magnitude of the voltage (driving voltage) applied to the piezoelectric film 10, and emits sound according to the driving voltage applied to the piezoelectric film 10.
In addition, by adjusting the mass of the piezoelectric film 10 according to the spring constant of the vibration plate 102, the sound pressure level can be improved. If the mass of the piezoelectric film 10 is large, the vibration plate 102 is bent, and therefore vibration of the vibration plate 102 at the time of driving may be suppressed. On the other hand, if the mass of the piezoelectric film 10 is small, the resonance frequency becomes high, and there is a possibility that the vibration of the vibration plate 102 at a low frequency is suppressed. Considering these points, it is preferable to appropriately adjust the mass of the piezoelectric film 10 according to the spring constant of the vibration plate 102.
While the piezoelectric element of the present invention has been described in detail, the present invention is not limited to the above examples, and various modifications and changes can be made without departing from the spirit of the present invention.
Examples
Hereinafter, the present invention will be described in more detail with reference to specific examples thereof. The present invention is not limited to this embodiment, and materials, amounts of use, ratios, processing contents, processing sequences, and the like shown in the following embodiments can be appropriately changed without departing from the spirit of the present invention.
[ Production of piezoelectric film ]
The piezoelectric film was produced by the method shown in fig. 10 to 12 described above.
First, cyanoethylated PVA (CR-V Shin-Etsu Chemical Co., manufactured by Ltd.) was dissolved in Dimethylformamide (DMF) at the following composition ratio. Then, PZT particles were added as piezoelectric particles in the following composition ratio, and stirred with a propeller mixer (rotation speed 2000 rpm) to prepare a paint for forming a piezoelectric layer.
PZT particle 300 parts by mass of
Cyanoethylated PVA & lt/EN & gt 30 parts by mass
DMF & lt/EN & gt 70 parts by mass
The PZT particles are obtained by sintering a commercially available PZT raw material powder at 1000 to 1200 ℃ and then pulverizing and classifying the powder so that the average particle diameter becomes 5 μm.
On the other hand, a sheet of copper film having a thickness of 0.3 μm was vacuum deposited on a PET film having a thickness of 4. Mu.m. That is, in this example, the 1 st electrode layer and the 2 nd electrode layer were copper vapor deposited films having a thickness of 0.3. Mu.m, and the 1 st protective layer and the 2 nd protective layer were PET films having a thickness of 4. Mu.m.
A coating material for forming a piezoelectric layer prepared in advance was applied to the 2 nd electrode layer (copper vapor deposited film) of the sheet-like material using a bevel blade coater. The coating material was applied so that the film thickness of the dried coating film became 50. Mu.m.
Subsequently, DMF was evaporated by heating and drying the coated material on the sheet on a heating plate of 120 ℃. Thus, a2 nd electrode layer made of copper was provided on the 2 nd protective layer made of PET, and a piezoelectric laminate having a piezoelectric layer (polymer composite piezoelectric layer) with a thickness of 50 μm was produced thereon.
The piezoelectric layer thus produced was subjected to polarization treatment in the thickness direction.
On the piezoelectric laminate subjected to the polarization treatment, a sheet-like material obtained by vapor deposition of the thin film on a PET film was laminated with the 1 st electrode layer (copper film side) facing the piezoelectric layer.
Next, the piezoelectric laminate and the laminate of the sheet were thermally bonded at a temperature of 120 ℃ using a lamination apparatus, and the piezoelectric layer and the 1 st electrode layer were bonded to each other, thereby producing a piezoelectric film.
Example 1
The piezoelectric films thus produced were cut out to 170mm×150mm, and folded back 4 times in the direction of the 170mm side, and the piezoelectric films were laminated with an adhesive layer (acrylic adhesive) to each other, thereby producing a piezoelectric element having a laminated portion having a length Lb30mm×a width Wb150mm and a protruding portion having a length La9mm×a width Wa150 mm.
The ratio Ps of the area Sa of the protruding portion to the area Sb of the laminated portion was 0.3. The length Ya of the side of the protruding portion in contact with the laminated portion was 150mm.
10 Such piezoelectric elements were fabricated.
Example 2
10 Piezoelectric elements were fabricated in the same manner as in example 1, except that the structure was such that 12 protrusions (see fig. 8) of length La11mm×width Wa10mm were provided.
The ratio Ps of the (total) area Sa of the protruding portions to the area Sb of the laminated portion was 0.29. The length Ya of the side of the protruding portion in contact with the laminated portion was 10mm.
In addition, in each of the plurality of protruding portions, the 1 st electrode layer and the 2 nd electrode layer are connected to an external power source.
Example 3
10 Piezoelectric elements were fabricated in the same manner as in example 1, except that the structure was such that 14 protrusions having a length la9.5mm×a width Wa of 10mm were provided.
The ratio Ps of the (total) area Sa of the protruding portions to the area Sb of the laminated portion was 0.30. The length Ya of the side of the protruding portion in contact with the laminated portion was 10mm.
In addition, in each of the plurality of protruding portions, the 1 st electrode layer and the 2 nd electrode layer are connected to an external power source.
Example 4
10 Piezoelectric elements were fabricated in the same manner as in example 1, except that the structure was such that 1 protrusion portion of length La37mm×width Wa37mm was provided.
The ratio Ps of the area Sa of the protruding portion to the area Sb of the laminated portion was 0.30. The length Ya of the side of the protruding portion in contact with the laminated portion was 37mm.
Example 5
10 Piezoelectric elements were fabricated in the same manner as in example 1, except that the structure (see fig. 6) was one having 1 hexagonal protruding portion with a 1-sided length of 22.5 mm.
The ratio Ps of the area Sa of the protruding portion to the area Sb of the laminated portion was 0.29. The length Ya of the side of the protruding portion in contact with the laminated portion was 22.5cm.
Example 6
10 Piezoelectric elements were fabricated in the same manner as in example 1, except that the structure was such that 1 protrusion portion of length La60mm×width Wa4mm was provided.
The ratio Ps of the area Sa of the protruding portion to the area Sb of the laminated portion was 0.05. The length Ya of the side of the protruding portion in contact with the laminated portion was 4mm.
Example 7
10 Piezoelectric elements were fabricated in the same manner as in example 1, except that the structure was such that 1 protrusion portion of length La4mm×width Wa25mm was provided.
The ratio Ps of the area Sa of the protruding portion to the area Sb of the laminated portion was 0.02. The length Ya of the side of the protruding portion in contact with the laminated portion was 25mm.
Comparative example 1
10 Piezoelectric elements were fabricated in the same manner as in example 1, except that the structure was made with 1 protrusion having a length La of 10mm×a width Wa of 150 mm.
The ratio Ps of the area Sa of the protruding portion to the area Sb of the laminated portion was 0.33. The length Ya of the side of the protruding portion in contact with the laminated portion was 150mm.
Comparative example 2
10 Piezoelectric elements were fabricated in the same manner as in example 1, except that the structure was such that 1 protrusion portion having a length La of 70mm×a width Wa of 3mm was provided.
The ratio Ps of the area Sa of the protruding portion to the area Sb of the laminated portion was 0.05. The length Ya of the side of the protruding portion in contact with the laminated portion was 3mm.
Comparative example 3
10 Piezoelectric elements were fabricated in the same manner as in example 1, except that the structure was such that 1 protrusion portion having a length La4mm×a width Wa of 10mm was provided.
The ratio Ps of the area Sa of the protruding portion to the area Sb of the laminated portion was 0.01. The length Ya of the side of the protruding portion in contact with the laminated portion was 10mm.
[ Evaluation ]
With respect to the electroacoustic transducers of each of the examples and comparative examples thus produced, the variation in sound pressure and the temperature reached were evaluated.
< Sound pressure >
An electroacoustic transducer was fabricated by attaching the surface of the fabricated piezoelectric element opposite to the protruding portion to a vibration plate. As the vibration plate, a plate-like member having a size of 500mm×450mm, a thickness of 0.8mm, and a material of aluminum (a 5052) was used. The widthwise direction of the vibration plate is aligned with the longitudinal direction of the piezoelectric element, and the center of the vibration plate is aligned with the center of the laminated portion of the piezoelectric element and bonded. As an adhesive layer for adhering the piezoelectric element and the vibration plate, an acrylic adhesive is used.
A sinusoidal sweep signal having a frequency of 1kHz to 20kHz and a voltage of 50Vrms was applied to the piezoelectric element, and the sound pressure was measured by a microphone located at a distance of 1m from the center of the diaphragm.
The above measurement was performed on 10 samples, and the difference between the maximum value and the minimum value of the sound pressure at 15kHz was set as the sound pressure deviation. If the sound pressure deviation is less than 7dB, the desired characteristics are satisfied.
< Reach temperature >)
In the same manner as in the case of measuring the sound pressure, an SN2 signal (specification of a noise signal specified by JEITA) of 40Vrms was input in a state where the produced piezoelectric element was attached to the vibration plate, and the temperature reached on the surface of the piezoelectric element after 30 minutes was measured by a thermography method (U5855A manufactured by Keysight Technologies). The temperature measurement position of the piezoelectric element is set to an arbitrary position that shows the highest reached temperature. When the temperature is 50 ℃ or lower, desired characteristics are satisfied.
The results are shown in table 1.
TABLE 1
As is clear from table 1, the embodiment of the present invention has less variation in sound pressure and a low reaching temperature than the comparative example. It is found that the deviation is large because the area ratio of the protruding portion of comparative example 1 is large. It is found that the protruding portion of comparative example 2 has a short length of the side contacting the laminated portion, and thus the reaching temperature is high. It is found that the area ratio of the protruding portion in comparative example 3 is small, and thus the reaching temperature is high.
It is also apparent from the comparison of examples 1 to 5 that, when the areas of the protruding portions are substantially the same, the longer the length of the side of the protruding portion that contacts the laminated portion is, the lower the reaching temperature is.
As is clear from the comparison between example 1 and examples 6 and 7, the smaller the area ratio of the protruding portion is, the smaller the sound pressure deviation is.
From the above, the effects of the present invention are remarkable.
Industrial applicability
The piezoelectric element of the present invention can be preferably used for various sensors such as an acoustic wave sensor, an ultrasonic sensor, a pressure sensor, a tactile sensor, a strain sensor, and a vibration sensor (particularly, it is suitable for use in manufacturing site detection such as foundation point detection such as crack detection and foreign matter contamination detection); acoustic elements such as microphones, speakers, and exciters (specific applications include noise cancellers (used for vehicles, commuter electric vehicles, airplanes, robots, and the like), artificial vocal cords, buzzers for pest/pest intrusion prevention, furniture, wallpaper, photographs, helmets, goggles, headrests, signs, robots, and the like); a haptic interface for automobiles, smart phones, smart watches, gaming machines, etc.; ultrasonic transducers such as ultrasonic probes and wave receivers in water; an actuator used for preventing adhesion, conveyance, stirring, dispersion, grinding, and the like of water droplets; damping materials (dampers) used in sports equipment such as containers, rides, buildings, snowboards, and rackets; and vibration power generation devices for roads, floors, mattresses, chairs, shoes, tires, wheels, computer keyboards, and the like.
Symbol description
10-Piezoelectric film, 10 a-protruding portion, 10 b-laminated portion, 12a, 12 c-sheet, 12 b-piezoelectric laminated body, 14-adhesive layer, 20-piezoelectric body layer, 24-1 st electrode layer, 26-2 nd electrode layer, 28-1 st protective layer, 30-2 nd protective layer, 34-substrate, 36-piezoelectric body particle, 40-connecting portion, 50a to 50 e-piezoelectric element, 100-electroacoustic transducer, 102-vibration plate, 104-adhesive layer.
Claims (7)
1. A piezoelectric element is formed by laminating a plurality of piezoelectric films by folding back the piezoelectric films 1 or more times, the piezoelectric films having piezoelectric layers, electrode layers provided on both sides of the piezoelectric layers, and protective layers provided on the electrode layers,
The piezoelectric element has a protruding portion protruding from a laminated portion where 2 or more piezoelectric films are laminated in a plan view,
The protruding portion has a connection portion for connecting the electrode layer with an external power source,
The ratio of the area of the protruding portion to the area of the laminated portion is in the range of 0.02 to 0.3, and the length of the side of the protruding portion that contacts the laminated portion is 4mm or more.
2. The piezoelectric element according to claim 1, wherein,
The piezoelectric element has a plurality of the protruding portions,
The ratio of the total area of the protruding portions to the area of the laminated portion is in the range of 0.02 to 0.3,
The length of the side of each protruding portion, which is in contact with the laminated portion, is 4mm or more.
3. The piezoelectric element according to claim 2, wherein,
The number of the protruding parts is 12 or less.
4. The piezoelectric element according to claim 1, wherein,
The protruding portion has a rectangular shape in plan view.
5. The piezoelectric element according to claim 1, wherein,
The piezoelectric layer is composed of a polymer composite piezoelectric body including piezoelectric particles in a matrix including a polymer material.
6. An electroacoustic transducer formed by attaching the piezoelectric element according to any one of claims 1 to 5 to a vibration plate.
7. The electroacoustic transducer of claim 6, wherein,
The lamination portion of the side surface of the piezoelectric element having the protruding portion is adhered to the vibration plate.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2021157983 | 2021-09-28 | ||
| JP2021-157983 | 2021-09-28 | ||
| PCT/JP2022/030855 WO2023053750A1 (en) | 2021-09-28 | 2022-08-15 | Piezoelectric element, and electro-acoustic converter |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN117957858A true CN117957858A (en) | 2024-04-30 |
Family
ID=85782338
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202280060037.6A Pending CN117957858A (en) | 2021-09-28 | 2022-08-15 | Piezoelectric element and electroacoustic transducer |
Country Status (3)
| Country | Link |
|---|---|
| CN (1) | CN117957858A (en) |
| TW (1) | TW202315175A (en) |
| WO (1) | WO2023053750A1 (en) |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6054486A (en) * | 1983-09-05 | 1985-03-28 | Toshiba Corp | Lead wire connecting portion of polymer element |
| JP6005089B2 (en) * | 2013-03-29 | 2016-10-12 | 富士フイルム株式会社 | Electroacoustic conversion film |
| JP6201583B2 (en) * | 2013-09-30 | 2017-09-27 | 株式会社村田製作所 | Piezoelectric device and method for manufacturing piezoelectric device |
| WO2020095812A1 (en) * | 2018-11-08 | 2020-05-14 | 富士フイルム株式会社 | Laminated piezoelectric element and electro-acoustic transducer |
| EP4149118A4 (en) * | 2020-05-07 | 2023-10-18 | FUJIFILM Corporation | Piezoelectric element and piezoelectric speaker |
-
2022
- 2022-08-15 CN CN202280060037.6A patent/CN117957858A/en active Pending
- 2022-08-15 WO PCT/JP2022/030855 patent/WO2023053750A1/en active Application Filing
- 2022-08-24 TW TW111131866A patent/TW202315175A/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| TW202315175A (en) | 2023-04-01 |
| WO2023053750A1 (en) | 2023-04-06 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN113508605B (en) | Electroacoustic transducer | |
| TW202143515A (en) | Piezoelectric element and piezoelectric speaker | |
| KR102617510B1 (en) | Polymer composite piezoelectric material and piezoelectric film | |
| KR102600731B1 (en) | Piezoelectric films, laminated piezoelectric elements and electroacoustic transducers | |
| JP7177268B2 (en) | Polymer Composite Piezoelectric Materials and Piezoelectric Films | |
| CN117957858A (en) | Piezoelectric element and electroacoustic transducer | |
| WO2023248696A1 (en) | Piezoelectric film, piezoelectric element, electroacoustic transducer, and method for manufacturing piezoelectric film | |
| CN118044228A (en) | Piezoelectric element and electroacoustic transducer | |
| WO2023157532A1 (en) | Piezoelectric element, and electro-acoustic converter | |
| WO2023053751A1 (en) | Piezoelectric element, and electro-acoustic converter | |
| WO2023047958A1 (en) | Multilayer piezoelectric element and electroacoustic transducer | |
| WO2022196202A1 (en) | Piezoelectric element | |
| WO2023153126A1 (en) | Piezoelectric element and electroacoustic transducer | |
| WO2023181699A1 (en) | Electroacoustic transducer | |
| WO2023188929A1 (en) | Piezoelectric film, piezoelectric element, and electroacoustic transducer | |
| WO2023188966A1 (en) | Piezoelectric film, piezoelectric element, and electroacoustic transducer | |
| WO2023053931A1 (en) | Piezoelectric element and piezoelectric speaker | |
| WO2023166892A1 (en) | Electroacoustic transducer | |
| WO2023149233A1 (en) | Piezoelectric film and laminated piezoelectric element | |
| WO2023048022A1 (en) | Piezoelectric element and piezoelectric speaker | |
| WO2023286544A1 (en) | Piezoelectric film | |
| TW202313325A (en) | Piezoelectric element and electroacoustic transducer | |
| CN116783902A (en) | Piezoelectric film | |
| CN118020316A (en) | Piezoelectric element and piezoelectric speaker | |
| TW202318690A (en) | Piezoelectric film and laminated piezoelectric element |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination |