PIEZOELECTRIC ELEMENT AND PIEZOELECTRIC VIBRATOR HAVING THE SAME
A piezoelectric element and a piezoelectric vibrator having the same are disclosed. A piezoelectric element according to the present invention includes: a plurality of ceramic piezoelectric layers configured to contract and expand according to supply of electric power; an electrode pattern constituted with electrodes laminated alternately with the plurality of ceramic piezoelectric layers; and a flexible layer formed on a surface of an upper-most electrode of the electrode pattern so as to protect the upper-most electrode and configured to prevent a crack from occurring by contracting and expanding according to contraction and expansion of the ceramic piezoelectric layers.
1 . A piezoelectric vibrator comprising:
a vibrating plate; and
a piezoelectric element coupled to an upper surface of the vibrating plate and configured to vibrate the vibrating plate,
wherein the piezoelectric element comprises:
a plurality of ceramic piezoelectric layers configured to contract and expand according to supply of electric power;
an electrode pattern constituted with electrodes laminated alternately with the plurality of ceramic piezoelectric layers; and
a flexible layer formed on a surface of an upper-most electrode of the electrode pattern.
2 . The piezoelectric vibrator of claim 1 , wherein a thickness of the flexible layer is greater than or equal to ¼ and smaller or equal to ⅓ of a thickness of the piezoelectric element.
3 . The piezoelectric vibrator of claim 1 , wherein the flexible layer is made of a material comprising resin.
4 . The piezoelectric vibrator of claim 1 , further comprising a ceramic cover layer coupled to a lower portion of a lower-most layer of the plurality of ceramic piezoelectric layers and covering a lower-most electrode of the electrode pattern.
5 . The piezoelectric vibrator of claim 1 , further comprising an adhesive material interposed between the piezoelectric element and the vibrating plate.
6 . The piezoelectric vibrator of claim 1 , wherein the plurality of ceramic piezoelectric layers comprise a PNN-PZT ceramic material.
7 . The piezoelectric vibrator of claim 6 , wherein the plurality of ceramic piezoelectric layers further comprise a sintering aid comprising at least one of NiO, CuO, ZnO and PbO.
8 . The piezoelectric vibrator of claim 1 , wherein the electrodes of the electrode pattern comprise at least one of Cu, Ag and Pd.
9 . The piezoelectric vibrator of claim 1 , wherein the piezoelectric element further comprises a via formed by penetrating the plurality of ceramic piezoelectric layers in order to electrically connect the electrodes of the electrode pattern.
10 . The piezoelectric vibrator of claim 9 , wherein the piezoelectric element further comprises a terminal electrically connected with the electrode pattern and formed to be exposed on a surface of an upper-most layer of the plurality of ceramic piezoelectric layers.
11 . The piezoelectric vibrator of claim 10 , wherein the via and the terminal are each provided in two pairs that are electrically connected with the electrodes.
12 . The piezoelectric vibrator of claim 1 , further comprising an external electrode formed on lateral surfaces of the plurality of ceramic piezoelectric layers so as to electrically connect the electrodes of the electrode pattern.
13 . A piezoelectric element comprising:
a plurality of ceramic piezoelectric layers configured to contract and expand according to supply of electric power;
an electrode pattern constituted with electrodes laminated alternately with the plurality of ceramic piezoelectric layers; and
a flexible layer formed on a surface of an upper-most electrode of the electrode pattern.
14 . The piezoelectric element of claim 13 , wherein a thickness of the flexible layer is greater than or equal to ¼ and smaller or equal to ⅓ of a thickness of the piezoelectric element.
15 . The piezoelectric element of claim 13 , wherein the flexible layer is made of a material comprising resin.
16 . The piezoelectric element of claim 13 , further comprising a ceramic cover layer coupled to a lower portion of a lower-most layer of the plurality of ceramic piezoelectric layers and covering a lower-most electrode of the electrode pattern.
17 . The piezoelectric element of claim 13 , wherein the plurality of ceramic piezoelectric layers further comprise a PNN-PZT ceramic material and a sintering aid comprising at least one of NiO, CuO, ZnO and PbO.
18 . The piezoelectric element of claim 13 , further comprising a via formed by penetrating the plurality of ceramic piezoelectric layers in order to electrically connect the electrodes of the electrode pattern.
19 . The piezoelectric element of claim 18 , further comprising a terminal electrically connected with the electrode pattern and formed to be exposed on a surface of an upper-most layer of the plurality of ceramic piezoelectric layers.
20 . The piezoelectric element of claim 19 , wherein the via and the terminal are each provided in two pairs that are electrically connected with the electrodes.
21 . The piezoelectric element of claim 13 , further comprising an external electrode formed on lateral surfaces of the plurality of ceramic piezoelectric layers so as to electrically connect the electrodes of the electrode pattern.