Piezoelectric vibrator and sensor
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 Ca 3 Ta(Ga 1-x Al x ) 3 Si 2 O 14 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 Ca 3 Nb(Ga 1-x Al x ) 3 Si 2 O 14 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.
1. A piezoelectric vibrator comprising at least one vibrating piece made of a Ca 3 Ta(Ga 1-x Al x ) 3 Si 2 O 14 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.
2. The piezoelectric vibrator according to claim 1 , wherein 20x+20.16≤θ≤21x+22.083 is set.
3. A piezoelectric vibrator comprising at least one vibrating piece made of a Ca 3 Nb(Ga 1-x Al x ) 3 Si 2 O 14 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.
4. The piezoelectric vibrator according to claim 3 , wherein 27.6x+24.367≤θ≤27.8x+25.783 is set.
5. A piezoelectric vibrator comprising at least one vibrating piece made of a Ca 3 (Ta 1-y Nb y )(Ga 1-x Al x ) 3 Si 2 O 14 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.
6. 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.
7. 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.
8. 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.
9. 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.
10. 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.
11. 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.
12. 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.
13. 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.
14. 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.
15. 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.
16. 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.
17. 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.
18. 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.