Hermetically sealed hydrophones with very low acceleration sensitivity
First Claim
1. A hydrophone comprising:
- a single piezoelectric crystal ring poled in the shear mode in the axial direction, said ring having an inner surface and an outer surface;
a metallic inner crystal support epoxied to the inner surface of the piezoelectric ring, said inner crystal support having an inertial mass;
a metallic outer crystal support epoxied to the outer surface of the piezoelectric ring, said outer crystal support having an inertial mass;
a metallic inner support shoe epoxied to the inner crystal support, said inner support shoe having an inertial mass;
a metallic outer support shoe epoxied to the outer crystal support, said outer support shoe having an inertial mass;
wherein a combined inner inertial mass of the metallic inner crystal support and the metallic inner support shoe is substantially the same as a combined outer inertial mass of the metallic outer crystal support and the metallic outer support shoe, and configured to provide no net shear force on the crystal ring during acceleration but provides a net shear force in response to an acoustic pressure.
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Abstract
An improved hydrophone is presented that has extremely low acceleration sensitivity, hermetic sealing, and is self-shielded. The hydrophone can also contain an integral amplifier and pressure/depth limiting switch. The hydrophone is also designed such that it can use a single standard piezoelectric sensing element in many hydrophone designs that have different acoustic pressure sensitivities but the same capacitance. Lastly, the sensor is also designed to be low cost in high volumes using standard accelerometer manufacturing techniques. A hydrophone is also designed such that it can use a single standard piezoelectric sensing element that can be incorporated into several hydrophone configurations with varying acoustic pressure sensitivities. The sensor is also designed to be low cost in high volumes.
38 Citations
10 Claims
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1. A hydrophone comprising:
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a single piezoelectric crystal ring poled in the shear mode in the axial direction, said ring having an inner surface and an outer surface; a metallic inner crystal support epoxied to the inner surface of the piezoelectric ring, said inner crystal support having an inertial mass; a metallic outer crystal support epoxied to the outer surface of the piezoelectric ring, said outer crystal support having an inertial mass; a metallic inner support shoe epoxied to the inner crystal support, said inner support shoe having an inertial mass; a metallic outer support shoe epoxied to the outer crystal support, said outer support shoe having an inertial mass; wherein a combined inner inertial mass of the metallic inner crystal support and the metallic inner support shoe is substantially the same as a combined outer inertial mass of the metallic outer crystal support and the metallic outer support shoe, and configured to provide no net shear force on the crystal ring during acceleration but provides a net shear force in response to an acoustic pressure. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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Specification