A piezo-electret vibration sensor designed for acoustic-electric guitars is evaluated. A piezo-electret, which is a cellular polypropylene electret film, is laminated with a 150-μm-thick polyethylene terephthalate (PET) film to achieve sufficient durability for general use. Additionally, a 10-μm-thick silver electrode is printed on the top surface as a shield electrode. This electrode adds a mass of only 63 mg to the sensor. The sensor is attached to the soundboard of a guitar body. An impact force is applied to the top of the saddle of the guitar body. The output voltage of the sensor owing to the vibration of the soundboard is measured by a voltage follower and an FFT analyzer. Conventional sensors that use lead zirconate titanate (PZT) ceramics are also tested. The results show that only the piezo-electret sensor detects the vibration of the soundboard over a wide frequency range up to 10 kHz. The time response of the sensor also corresponds to the vibration of the soundboard. However, the output voltage of the sensor is 1/10 to 1/100 of that of the PZT sensors. The effective d33 value of the sensor is 1.58 pC/N at 1 kHz. The value is only 1/280 of the apparent d33 value of the piezo-electret, owing to an increase in the effective elastic modulus in the thickness direction caused by lamination with the PET film.

中文翻译：

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专为原声电吉他设计的压电驻极体振动传感器

对专为原声-电吉他设计的压电驻极体振动传感器进行了评估。压电驻极体是一种蜂窝状聚丙烯驻极体薄膜，它与 150 微米厚的聚对苯二甲酸乙二醇酯 (PET) 薄膜层压在一起，以获得足够的耐久性以供一般使用。此外，一个 10 微米厚的银电极印在顶面上作为屏蔽电极。该电极仅为传感器增加了 63 毫克的质量。传感器安装在吉他琴身的音板上。一个冲击力作用在吉他琴身的鞍座顶部。由于音板的振动，传感器的输出电压由电压跟随器和 FFT 分析仪测量。还测试了使用锆钛酸铅 (PZT) 陶瓷的传统传感器。结果表明，只有压电驻极体传感器才能在高达 10 kHz 的宽频率范围内检测音板的振动。传感器的时间响应也对应于音板的振动。但是，传感器的输出电压是 PZT 传感器的 1/10 到 1/100。传感器的有效 d33 值在 1 kHz 时为 1.58 pC/N。该值仅为压电驻极体表观 d33 值的 1/280，这是由于与 PET 薄膜层压导致厚度方向的有效弹性模量增加。