Active noise mitigation window employing transparent piezoelectric film speakers

Noise pollution has a significant negative effect on psychological health and quality of life. The building envelop, particularly windows often constitutes to the primary path for external noise sources to travel into the buildings. Passive noise mitigation technologies are mainly effective at high frequencies and also cannot be applied when transparency is required. Although active noise mitigation can help to effectively suppress the low frequency noise, the current technology uses bulky and non-transparent electromagnetic speakers located at selected points, which often limits global noise cancellation effect over a large area and has aesthetical acceptance issue. Some research efforts have been focused on reducing the size of speakers to improve aesthetics; however by reducing size of speakers, low frequency performance of the noise mitigation system is often compromised. Here we have designed and produced transparent film speakers using a piezoelectric polymer aiming at active noise mitigation over increased area for window applications. The performance properties of our obtained transparent speakers, including the simulation and experimental results of the effectiveness for active noise mitigation in a window structure, are reported. The potential and challenges of applying large area transparent piezoelectric film speakers for noise mitigation windows is analyzed.