# US 9,873,248 B2 · Piezoelectric element, piezoelectric member, liquid discharge head, and recording device each using piezoelectric element

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- Number: US 9,873,248 B2
- Document ID: US9873248B2
- Status: Granted
- Kind: B2
- Application number: 15/039,987
- Filed: 2014-11-28
- Published: 2017-02-09
- Granted: 2018-01-23
- Earliest claimed: 2013-11-28
- Assignees: KYOCERA Corporation
- Applicants: KYOCERA Corporation
- Inventors: Makoto Higashibeppu; Shuuhei Tabata; Tomonori Eguchi; Izuru Sato
- Web page: https://patentgrep.com/patent/US9873248B2

## CPC

- B41J 2/14201: {Structure of print heads with piezoelectric elements}
- B41J 2/14209: {of finger type, chamber walls consisting integrally of piezoelectric material}
- B41J 2/14233: {of film type, deformed by bending and disposed on a diaphragm}
- B41J 2/155: for line printing
- H10N 30/2047: {Membrane type}
- H10N 30/8542: {Alkali metal based oxides, e.g. lithium, sodium or potassium niobates}
- B41J 2002/14403: {including a filter}
- B41J 2002/14459: {Matrix arrangement of the pressure chambers}
- B41J 2202/20: Modules
- B41J: TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
- H10N: ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR

## Abstract

The present invention aims at providing a piezoelectric element with less characteristic variations with time, and a liquid discharge head and a recording device each using the piezoelectric element. The piezoelectric element 30 of the present invention is the piezoelectric body 30 (piezoelectric ceramic layer 21b) containing a potassium sodium niobate composition as a primary component. The piezoelectric body extends in a planar direction. A compressive stress is applied in the planar direction. A phase transition point between a tetragonal crystal system and an orthorhombic crystal system is −20° C. or below.

## Claims

### Claim 1

A piezoelectric element comprising:
a piezoelectric body containing a potassium sodium niobate composition as a primary component,
wherein the piezoelectric body extends in a planar direction and is subjected to a compressive stress in the planar direction, and a phase transition point between a tetragonal crystal system and an orthorhombic crystal system is −20° C. or below.

### Claim 2 (depends on 1)

The piezoelectric element according to claim 1, wherein when the potassium sodium niobate composition is expressed by a composition formula: (1-x){(K1-aNaa)1-bLib}c(Nb1-d-eTadSbe)O2.5+C/2+xB1α(Al1-βA2β)O3,
0.0024≦x≦0.008,
0.66≦a+3×b≦0.74,
0.02≦b≦0.10,
0.980≦c≦1.000,
0.04≦d≦0.10,
0≦e≦0.08,
⅔≦α≦1, and
⅓≦β≦⅔, and
wherein A1 is at least one selected from an element group consisting of Mg, Cu, and Zn, A2 is at least one selected from an element group consisting of Nb, Ta, Sb, Ti, Zr, Hf, Ge, Sn, and Ce, and B1 is at least one selected from an element group consisting of Bi, Ca, Ba, and Sr.

### Claim 3 (depends on 2)

The piezoelectric element according to claim 2, wherein a crystal axis ratio c/a in the tetragonal crystal system of the potassium sodium niobate composition is 1.01 or more.

### Claim 4 (depends on 2)

A piezoelectric member comprising:
the piezoelectric element according to claim 2; and
a support body that is connected to the piezoelectric body and has a larger coefficient of thermal expansion than the piezoelectric body.

### Claim 5 (depends on 1)

The piezoelectric element according to claim 1, wherein a crystal axis ratio c/a in the tetragonal crystal system of the potassium sodium niobate composition is 1.01 or more.

### Claim 6 (depends on 1)

A piezoelectric member comprising:
the piezoelectric element according to claim 1; and
a support body that is connected to the piezoelectric body and has a larger coefficient of thermal expansion than the piezoelectric body.