Piezoelectric transducer for a hearing aid using PZT thin film

Yasui, Hidehiko; Kurosawa, Minoru; Morita, Takeshi; Kanda, Takefumi; Higuchi, Toshiro

doi:10.1121/1.421745

“…There have been many general studies on improving the characteristics of the diaphragm oscillator in the size range from 100 µm to mm order, corresponding to the frequency band from 100 kHz to MHz order. [32][33][34] It is obvious from Eq. ( 1) that, for a 20 MHz band transducer, the size should be reduced compared with that of a conventional device.…”

Section: Introductionmentioning

confidence: 99%

Characteristic analysis of diaphragm-type transducer that is thick relative to its size

Ishiguro¹,

Zhu²,

Tagawa³

et al. 2017

Jpn. J. Appl. Phys.

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In recent years, high-performance piezoelectric micromachined ultrasonic transducers (PMUTs) have been fabricated by micro electro mechanical systems (MEMS) technology. For high-resolution imaging, it is important to broaden the frequency bandwidth. By reducing the diaphragm size to increase the resonance frequency, the film thickness becomes relatively larger and hence the transmitting and receiving characteristics may different from those of a usual thin diaphragm. In this study, we examine the performance of a square-diaphragm-type lead zirconate titanate (PZT) transducer through simulations. To realize the desired resonance frequency of 20 MHz, firstly, the diaphragm size and the thickness of the layers of PZT and Si constituting a PMUT are examined, and then, three PZT/Si models with different thicknesses are selected. Subsequently, using the models, we analyze the transmitting efficiency, transmitting bandwidth, receiving sensitivity (piezoelectric voltage/electric charge), and receiving bandwidth using an FEM simulator. It is found that the proposed models can transmit ultrasound independently of the diaphragm vibration and have wide bandwidth of the receiving frequency as compared with that of a typical PMUT.

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“…We have reported a micro-ultrasonic motor [1], a vibration touch probe sensor [2,3], and an ear horn [4], all of which use hydrothermal PZT ®lm. The hydrothermal method utilizes the chemical reaction between titanium base metal and the melted ions at high temperatures in aqueous solutions.…”

Section: Hydrothermal Deposition Of Pzt Filmmentioning

confidence: 99%

“…This process is based on the single process [7] for the ®rst step. Process B indicated in Table 2 was applied to micro-ultrasonic motors [8] and an ear phone [4]. Process B involves improved nucleation and crystal growth processes.…”

Section: Hydrothermal Deposition Of Pzt Filmmentioning

confidence: 99%

Performance of hydrothermal PZT film on high intensity operation

Kurosawa

¹

,

Yasui

²

,

Kanda

³

et al. 2001

Sensors and Actuators A: Physical

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The deposition processes of PZT thin ®lms have been described in many reports, yet there have been no descriptions of the performance of PZT ®lms at high intensity operation. Hydrothermally-deposited PZT ®lm transducers were examined at large vibration amplitude levels at resonance frequencies. It was demonstrated that the hydrothermal PZT ®lm expresses superior performance with regard to linearity and maximum vibration velocity. The linearity of frequency responses at around the resonance frequency was excellent and superior to bulk material up to high intensity operation. The characteristics of longitudinal transducers using ®lms formed under two deposition processes were tested. The maximum vibration velocity was 2.24 m/s when the thickness of the ®lm was 38 mm and the driving voltage was 145 V p±p . This velocity value was much larger than bulk PZT materials for high power applications. #

show abstract

“…We have reported a micro-ultrasonic motor [1], a vibration touch probe sensor [2,3], and an ear horn [4], all of which use hydrothermal PZT ®lm. The hydrothermal method utilizes the chemical reaction between titanium base metal and the melted ions at high temperatures in aqueous solutions.…”

Section: Hydrothermal Deposition Of Pzt Filmmentioning

confidence: 99%

Performance of hydrothermal PZT film on high intensity operation

Kurosawa¹,

Yasui²,

Kanda³

et al.

Proceedings IEEE Thirteenth Annual International Conference on Micro Electro Mechanical Systems (Cat. No.00CH36308)

3

0

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The deposition processes of PZT thin ®lms have been described in many reports, yet there have been no descriptions of the performance of PZT ®lms at high intensity operation. Hydrothermally-deposited PZT ®lm transducers were examined at large vibration amplitude levels at resonance frequencies. It was demonstrated that the hydrothermal PZT ®lm expresses superior performance with regard to linearity and maximum vibration velocity. The linearity of frequency responses at around the resonance frequency was excellent and superior to bulk material up to high intensity operation. The characteristics of longitudinal transducers using ®lms formed under two deposition processes were tested. The maximum vibration velocity was 2.24 m/s when the thickness of the ®lm was 38 mm and the driving voltage was 145 V p±p . This velocity value was much larger than bulk PZT materials for high power applications.

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Piezoelectric transducer for a hearing aid using PZT thin film

Cited by 5 publications

References 1 publication

Characteristic analysis of diaphragm-type transducer that is thick relative to its size

Characteristic analysis of diaphragm-type transducer that is thick relative to its size

Performance of hydrothermal PZT film on high intensity operation

Performance of hydrothermal PZT film on high intensity operation

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