Development of a miniature second-order directional microphone diaphragm for hear

描述（由申请人提供）：本研究的主要目的是开发一种用于助听器的微型麦克风振膜，在语音重要的频率范围内实现对声音的二阶方向灵敏度。一款能够实现二级方向灵敏度的助听器能够对干扰语音的不需要的声音进行超过9分贝的衰减。实现这种降噪的现有方法是基于对来自三个非定向麦克风的信号的处理。这些系统的有效性受到麦克风自噪声的影响以及对麦克风之间不匹配的敏感性的阻碍。此外，容纳三个麦克风所需的空间限制了这些设备在更大的耳后助听器中的应用。所提出的研究方法避免了这些困难，通过开发一个单一的微型麦克风振膜，有可能在大部分可听频率范围内实现二阶定向响应。微型麦克风隔膜将被设计和制造，包括我们在当前NIH BRP奖下开发的成功的一阶定向麦克风隔膜的扩展。设计将进行优化，以确保二阶方向响应在尽可能宽的频率范围内占主导地位。这些设计将采用硅微加工技术制造，并将通过实验验证定向声响应。通过将二阶响应与响应的二阶导数的测量结果进行比较，可以完成制造隔膜的声学特性，该响应是通过测量隔膜附近一系列位置的声压而获得的。这一努力将证明创造一种微型二级麦克风振膜的可行性，这种振膜可以集成到助听器中。演示了实用的麦克风振膜设计后，将在后续研究中开发电子读出器，将振膜运动转换为电子信号。

DESCRIPTION (provided by applicant): The primary aim of the proposed research is to develop a miniature microphone diaphragm for hearing aids that achieves second-order directional sensitivity to sound over the frequency range that is important for speech. A hearing aid that can achieve second-order directional sensitivity can be capable of over 9 dB of attenuation of unwanted sounds that interfere with speech. Existing approaches to achieving this noise reduction are based on the processing of signals from three nondirectional microphones. The effectiveness of these systems has been hampered by the effects of microphone self-noise, and sensitivity to mismatches between the microphones. In addition, the space required to house the three microphones limits the application of these devices to larger behind-the-ear hearing aids. The approach of the proposed study avoids these difficulties by developing a single miniature microphone diaphragm that has the potential of achieving second-order directional response over much of the audible range of frequencies. Miniature microphone diaphragms will be designed and fabricated that comprises an extension of the successful first-order directional microphone diaphragms we have developed under our current NIH BRP award. The designs will be optimized to ensure that the 2nd order directional response dominates over as wide a range of frequencies as possible. The designs will be fabricated using silicon microfabrication technology and the directional acoustic response will be verified experimentally. The acoustic characterization of the fabricated diaphragms will be accomplished by comparing the 2nd order response with measurements of the 2nd derivative of the response obtained using measurements of the sound pressure at an array of locations in the vicinity of the diaphragm. This effort will demonstrate the feasibility of creating a miniature 2nd order microphone diaphragm that can be incorporated into hearing aids. Having demonstrated a practical microphone diaphragm design, an electronic read-out will be developed in a follow-on study to transduce the diaphragm motion into an electronic signal. PUBLIC HEALTH RELEVANCE: An estimated 500 million people worldwide suffer hearing loss, making it the number one disability in the world (Phonak, Sep 2006.) Hearing aids remain the primary form of treatment, yet the number one complaint of users is difficulty understanding speech in noisy environments. About half of those who could benefit from an aid do not use them because of design, stigma and cost issues; however a smaller hearing aid is their second most preferred solution. This proposed research will lead to a dramatic improvement in miniature, second-order directional microphone technology that will help users communicate in complex acoustical environments and attract new users.