# US 2018/0323366 A1 · Piezoelectric vibrator and sensor

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- Number: US 2018/0323366 A1
- Document ID: US20180323366A1
- Status: Published application
- Kind: A1
- Application number: 15/773,157
- Filed: 2016-11-04
- Published: 2018-11-08
- Earliest claimed: 2015-11-05
- Assignees: Piezo Studio Inc.; Tohoku University
- Applicants: Piezo Studio Inc.; Tohoku University
- Inventors: Akira YOSHIKAWA; Yuji OHASHI; Yuui YOKOTA; Kei KAMADA; Masatoshi ITO; Kenji INOUE; Hiroyuki AMANO
- Web page: https://patentgrep.com/patent/US20180323366A1

## CPC

- H03H 9/02102: {of temperature influence (cutting angles H03H9/02015)}
- H10N 30/302: {Sensors}
- G01N 29/022: {Fluid sensors based on microsensors, e.g. quartz crystal-microbalance [QCM], surface acoustic wave [SAW] devices, tuning forks, cantilevers, flexural plate wave [FPW] devices (microdevices per se B81B)}
- G01N 29/036: by measuring frequency or resonance of acoustic waves
- G01N 29/245: {Ceramic probes, e.g. lead zirconate titanate [PZT] probes}
- H03H 3/04: for obtaining desired frequency or temperature coefficient
- H03H 9/02039: {consisting of a material from the crystal group 32, e.g. langasite, langatate, langanite}
- H10N 30/20: with electrical input and mechanical output, e.g. functioning as actuators or vibrators
- H10N 30/30: with mechanical input and electrical output, e.g. functioning as generators or sensors
- H10N 30/853: Ceramic compositions
- H10N 30/872: {Interconnections, e.g. connection electrodes of multilayer piezoelectric or electrostrictive devices}
- H10N 30/88: Mounts; Supports; Enclosures; Casings
- G01N 2291/0256: Adsorption, desorption, surface mass change, e.g. on biosensors
- H03H 2003/0407: {Temperature coefficient}
- H03H: IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS (waveguides, resonators, lines or other devices of the waveguide type H01P)
- H10N: ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)

## Abstract

To provide a vibrator made of a piezoelectric crystal having a larger electromechanical coupling coefficient and a more satisfactory frequency-temperature characteristic than those of quartz, a vibrating piece (101) is made of a Ca3Ta(Ga1-xAlx)3Si2O14 single crystal (0<x≤1). In the single crystal, letting θ be a rotation angle from an X-Z plane about an X-axis serving as a rotation axis, 18x+17.5≤θ≤24x+24.5 is set. In addition, the vibrating piece (101) is made of a Ca3Nb(Ga1-xAlx)3Si2O14 single crystal (0<x≤1). In the single crystal of this arrangement, letting θ be a rotation angle from an X-Z plane about an X-axis serving as a rotation axis, 25x+23.083≤θ≤32x+26.167 is set.

## Claims

### Claim 1

A piezoelectric vibrator comprising at least one vibrating piece made of a Ca3Ta(Ga1-xAlx)3Si2O14 single crystal (0<x≤1),
wherein in the single crystal, letting θ be a rotation angle from an X-Z plane about an X-axis serving as a rotation axis, 18x+17.5≤θ≤24x+24.5 is set.

### Claim 2 (depends on 1)

The piezoelectric vibrator according to claim 1, wherein 20x+20.16≤θ≤21x+22.083 is set.

### Claim 3

A piezoelectric vibrator comprising at least one vibrating piece made of a Ca3Nb(Ga1-xAlx)3Si2O14 single crystal (0<x≤1),
wherein in the single crystal, letting θ be a rotation angle from an X-Z plane about an X-axis serving as a rotation axis, 25x+23.083≤θ≤32x+26.167 is set.

### Claim 4 (depends on 3)

The piezoelectric vibrator according to claim 3, wherein 27.6x+24.367≤θ≤27.8x+25.783 is set.

### Claim 5

A piezoelectric vibrator comprising at least one vibrating piece made of a Ca3(Ta1-yNby)(Ga1-xAlx)3Si2O14 single crystal (0<x≤1, 0≤y≤1),
wherein in the single crystal, letting θ be a rotation angle from an X-Z plane about an X-axis serving as a rotation axis, {18+(25−18)y}x+17.5+(23.083−17.5)y≤θ≤{24+(32−24)y}x+24.5+(26.167−24.5)y is set.

### Claim 6 (depends on 5)

The piezoelectric vibrator according to claim 5, wherein {20+(27.6−20)y}x+20.16+(24.367−20.16)y≤θ≤{21+(27.8−21)y}x+22.083+(25.783−22.083)y is set.

### Claim 7 (depends on 1)

The piezoelectric vibrator according to claim 1, further comprising:
an electrode provided on the vibrating piece;
a connection terminal connected to the electrode; and
a hermetic container storing the vibrating piece and filled with an inert gas.

### Claim 8 (depends on 1)

A sensor using a piezoelectric vibrator described in claim 1, comprising:
a measurement region provided on a vibrating piece and brought into contact with a measurement target substance; and
measurement means for detecting a mass of the substance that is in contact with the measurement region based on a change in a resonance frequency of the vibrator caused by the contact of the substance with respect to the measurement region.

### Claim 9 (depends on 2)

The piezoelectric vibrator according to claim 2, further comprising:
an electrode provided on the vibrating piece;
a connection terminal connected to the electrode; and
a hermetic container storing the vibrating piece and filled with an inert gas.

### Claim 10 (depends on 3)

The piezoelectric vibrator according to claim 3, further comprising:
an electrode provided on the vibrating piece;
a connection terminal connected to the electrode; and
a hermetic container storing the vibrating piece and filled with an inert gas.

### Claim 11 (depends on 4)

The piezoelectric vibrator according to claim 4, further comprising:
an electrode provided on the vibrating piece;
a connection terminal connected to the electrode; and
a hermetic container storing the vibrating piece and filled with an inert gas.

### Claim 12 (depends on 5)

The piezoelectric vibrator according to claim 5, further comprising:
an electrode provided on the vibrating piece;
a connection terminal connected to the electrode; and
a hermetic container storing the vibrating piece and filled with an inert gas.

### Claim 13 (depends on 6)

The piezoelectric vibrator according to claim 6, further comprising:
an electrode provided on the vibrating piece;
a connection terminal connected to the electrode; and
a hermetic container storing the vibrating piece and filled with an inert gas.

### Claim 14 (depends on 2)

A sensor using a piezoelectric vibrator described in claim 2, comprising:
a measurement region provided on a vibrating piece and brought into contact with a measurement target substance; and
measurement means for detecting a mass of the substance that is in contact with the measurement region based on a change in a resonance frequency of the vibrator caused by the contact of the substance with respect to the measurement region.

### Claim 15 (depends on 3)

A sensor using a piezoelectric vibrator described in claim 3, comprising:
a measurement region provided on a vibrating piece and brought into contact with a measurement target substance; and
measurement means for detecting a mass of the substance that is in contact with the measurement region based on a change in a resonance frequency of the vibrator caused by the contact of the substance with respect to the measurement region.

### Claim 16 (depends on 4)

A sensor using a piezoelectric vibrator described in claim 4, comprising:
a measurement region provided on a vibrating piece and brought into contact with a measurement target substance; and
measurement means for detecting a mass of the substance that is in contact with the measurement region based on a change in a resonance frequency of the vibrator caused by the contact of the substance with respect to the measurement region.

### Claim 17 (depends on 5)

A sensor using a piezoelectric vibrator described in claim 5, comprising:
a measurement region provided on a vibrating piece and brought into contact with a measurement target substance; and
measurement means for detecting a mass of the substance that is in contact with the measurement region based on a change in a resonance frequency of the vibrator caused by the contact of the substance with respect to the measurement region.

### Claim 18 (depends on 6)

A sensor using a piezoelectric vibrator described in claim 6, comprising:
a measurement region provided on a vibrating piece and brought into contact with a measurement target substance; and
measurement means for detecting a mass of the substance that is in contact with the measurement region based on a change in a resonance frequency of the vibrator caused by the contact of the substance with respect to the measurement region.