智慧型眼鏡助聽器---子計畫五：助聽器電聲元件

Abstract

本計畫我們提出目標在未來三年項目開發應用於智慧型行動眼鏡所配掛之高性能，低功耗助聽器之電磁驅動式電聲元件。在過去三年中，我們的研究工作已著重在CIC/ITC類型助聽器的技術開發，使它具有小外形尺寸，低功耗，低噪聲性能和適應中國用戶的特點。然而，儘管研究進展走得更遠更深，就愈發現所存在巨大技術挑戰並需要投入更多的研發工作。這些挑戰包括：喇叭陣列中的微型喇叭之間的機械耦合、導線結構限制的膜的剛性降低進而影響喇叭於低頻的頻率響應，由於磁鐵薄膜之尺寸限制和線圈結構導致較差之磁特性增益等，此外上研究目標之助聽器系統將進一步導入於智慧型眼鏡之中，系統電力損耗將不免加劇。為免因融入智慧型助聽器系統所需功耗而增加系統之負擔，超低功耗之助聽器系統目標將更為明確與必要性。因此為了有效解決這些問題，我們提出了幾種可能解決的方法，如背面喇叭空腔密封，利用仿生支撐結構實現高性能電磁式之能量擷取器，與具納米線形狀之磁性材料，...等。初步的模擬和實驗結果已揭示其可行性，並提供進一步改善器件的性能的實現途徑。其中預期喇叭將可操作於 1V，在小於 300mm3之實體體積下，有著頻寬大於10KHz且 >105dB SPL at 1KHz 之輸出，而所開發之發電機則將有>700mV, 30μW/cm2 之能量輸出。本分項計畫擬議研究的主要目標包含：1）開發低功耗，高帶寬，低失真喇叭陣列和電磁式麥克風，2）應用於助聽器之電磁式能源擷取器的開發，3）金屬-AAO 磁性納米複合材料之製造與納米複合永磁材料後膜製程之開發，4）異質整合助聽器系統和各式電聲元件物理模型建立。這些任務的成功，可以確保低功耗，高性能的助聽器之成功發展。而所開發之小尺寸，低功耗，低噪聲性能，製程簡單，高動態範圍、靈敏度與SPL之音頻組件在可預見的將來，將可應用於各式助聽器。同時，能量擷取器和伴隨著的高磁效能之電鍍式AAO納米複合硬磁塊與軟磁芯之電感技術，除可以進一步達成下世代助聽器的目標，亦可幫助推進的個人可攜式生物醫學設備。

This proposal presents our goal in the next three-year project regarding the development of high performance, low powered, EM-driven electroacoustic for smart hearing aids, which will be applied for smart glasses. In the past three years, our research effort has been put in developing a hearing aid with an CIC/ITC typed design, which has the characteristics of small form factor, low power consumption, low noise performance and adaptive for Chinese users. Nevertheless, while the research progress goes further deeper, several technical challenges have been found and more research efforts are required. The challenges include mechanical coupling between the microspeakers in the speaker array, membrane rigidity limited by feedthrough for low frequency response, poor magnetic property enhancement resulted by the magnet size and coil structure…etc. In addition, the power management of the proposed hearing aids would become more stringent since smart glasses unlike cell phones cannot be equipped with a large size battery. In addition to pre-existing wireless networking capability, image processing functions with voice control coupled with the hearing aid system will be further introduced to the smart glasses; the power consumption of the overall system will be inevitably intensified. In order to resolve the issues, we propose several possible approaches such as backside cavity sealing, the incorporation of sound absorber, biomimetic supporting structure for high performance EM-driven energy harvester, magnetic material with nanowire shape…and so on. Preliminary simulation and experimental results have revealed the feasibility for resolving these problems and providing the ways to realize the further improvement of the device performance. The expected outcome including a speaker array exhibits 10KHz bandwidth and 105dB SPL@1KHz, an EM-driven energy harvester (700mV and 20W/cm3), condenser microphone (Responsivity ~55 (dBV Pa−1) at 1 kHz)), soft magnetic thin film materials with high permeability (μr>200) and low coercivity magnetic field (Hc), and the hard magnet with high magnetic density ((BH) max> 30kJ/m3, and high coercivity magnetic field (Hc). The primary objectives of the proposed research are: 1) the development of a low power, wide bandwidth, low distortion microspeaker array and EM-based microphone, 2) the development of an EM-based energy harvester for hearing aids, 3) synthesis and characterization Co-based-AAO magnetic nanocomposite scheme and the development of process integration for the fabrication thick nanocomposite magnets, and 4) heterogeneous integration of hearing aids and physical modeling establishment of the integrated acoustic components. The success of these tasks can ensure the success in the development of low powered, high performance hearing aids.