Receiving Ultrasonic Transducer Based on Helmholtz Resonant Cavity and Reduced Air Damping

An ultrasonic transducer and air damping technology, which is applied in the direction of fluid using vibration, can solve the problems of cavity resonance frequency increase and quality factor Q decrease, so as to reduce air damping, prevent crosstalk, increase acoustic-electric conversion efficiency and The effect of sensitivity

Active Publication Date: 2020-08-25
武汉敏声新技术有限公司
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Problems solved by technology

When the fingerprint is pressed on the cavity, the resonance frequency of the cavity will increase and the quality factor Q will decrease.

Method used

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  • Receiving Ultrasonic Transducer Based on Helmholtz Resonant Cavity and Reduced Air Damping
  • Receiving Ultrasonic Transducer Based on Helmholtz Resonant Cavity and Reduced Air Damping
  • Receiving Ultrasonic Transducer Based on Helmholtz Resonant Cavity and Reduced Air Damping

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Embodiment Construction

[0030] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0031] like figure 1 , 2 , 3, 4, a receiving ultrasonic transducer based on a Helmholtz resonant cavity and reducing air damping, comprising a Helmholtz resonant cavity 2 at the upper part and a MEMS piezoelectric ultrasonic transducer at the lower part, the Helmholtz resonant cavity 2 and The MEMS piezoelectric ultrasonic transducers are bonded by bonding. The MEMS piezoelectric ultrasonic transducer is composed of a piezoelectric laminated structure on the top and a silicon substrate 5 with a cavity on the bottom.

[0032] The Helmholtz resonant cavity 2 is formed by bonding a silicon structure 4 with a cavity with an upper opening 4-1 above the piezoelectric stack structure. The piezoelectric laminated structure is bonded together to form a Helmholtz resonant cavity 2, and a Helmholtz resonant cavity hole is formed in the upper opening 4-1 ...

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Abstract

The invention discloses a receiving ultrasonic transducer based on a Helmholtz resonant cavity and reducing air damping. The receiving ultrasonic transducer comprises the Helmholtz resonant cavity located at the upper part and a MEMS piezoelectric ultrasonic transducer located at the lower part, wherein the Helmholtz resonant cavity and the MEMS piezoelectric ultrasonic transducer are combined through bonding, the MEMS piezoelectric ultrasonic transducer consists of an upper piezoelectric laminated structure and a lower cavity silicon substrate, the Helmholtz resonant cavity is composed of a cavity silicon structure with an upper opening above the piezoelectric laminated structure, the upper opening is formed in the upper portion of the cavity silicon structure to form a Helmholtz resonance cavity hole, air in the Helmholtz resonance cavity forms an air column of the Helmholtz resonance cavity, a hole is etched in the middle of the piezoelectric laminated structure to form a piezoelectric laminated hole, so that the Helmholtz resonance cavity communicates with the cavity silicon substrate, a plurality of radiation grooves are etched in the piezoelectric laminated structure by taking the piezoelectric laminated hole as a center, a cantilever beam is formed by the piezoelectric laminated structure between the plurality of radiation grooves, the end, connecting with the piezoelectric laminated structure, of the cantilever beam is a fixed end, and the end, connecting with the piezoelectric laminated hole, of the cantilever beam is a free end.

Description

technical field [0001] The invention belongs to the technical field of MEMS ultrasonic transducers, and relates to a receiving ultrasonic transducer based on a Helmholtz resonant cavity and reducing air damping. Background technique [0002] An ultrasonic transducer is a transducer element that can be used to both transmit and receive ultrasonic waves. When working in the transmitting mode, the electrical energy is converted into the vibration of the transducer through electrostatic force or inverse piezoelectric effect to radiate sound waves outward; when working in the receiving mode, the sound pressure acts on the surface of the transducer to make it vibrate, and the transducer The vibrations are then converted into electrical signals. At present, the most widely used ultrasonic sensors are mainly based on bulk piezoelectric transducers. The bulk piezoelectric transducers mainly use the thickness vibration mode of piezoelectric ceramics to generate ultrasonic waves. Sinc...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B06B1/06
CPCB06B1/0662B06B2201/55
Inventor 孙成亮吴志鹏林炳辉朱伟王磊胡博豪周禹
Owner 武汉敏声新技术有限公司
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