Study on fabrication processing and related characteristions of miniature ribbon microphone

• Main Authors: Cheng-You Suen, 孫誠佑
• Other Authors: Ray-Hua Horng
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/69647692038708467942

碩士 === 國立中興大學 === 精密工程學系所 === 98 === This thesis presents the characteristic of miniature ribbon microphone. They were fabricated by micro-electro-mechanical system techniques. To enhance the overall yield by reducing thermal stress and process temperature, the Ni/Co substrate separating technique was proposed. Moreover the optimum magnetic system of miniature ribbon microphone was established in accordance with the result of simulation and magnetic flux measurement, which remarkably improved its sensitivity and miniatured volume. The volumn of ribbon microphone can be miniatured from 66 mm×32 mm×7.2 mm (traditional) to 22 mm×15.5 mm×27.5 mm. As concerning the diaphragm, 1 μm-thick patterned polymer material can be fabricated by spin coating, which proceedes at relatively low temperature (130℃). This is believed to enhance sensitivity of ribbon microphone. Moreover, ribbon microphone is a pressure gradient type and the vibration velocity of diaphragm affected its sensitivity. This thesis indicates that the area of holes on the diaphragm was proportional to the mechanical sensitivity of diaphragm. According to this design and optimized fabrication (diaphragm with 2μm thickness, coil with 43.7cm length and 264Ω resistance), the responsivity of miniature ribbon microphone is -77.6 dBV/Pa (@ 1k Hz). The miniatured ribbon microphone fabricated in this work could fit in with commercial requirement (-50~-60 dBV/Pa) as using the suitable amplifier.