以聚乙烯醇薄膜塗佈於表面聲波元件之濕度感測器的特性之研究

Humidity sensing characteristics of polyvinyl-alcohol coated surface acoustic wave devices

陳雲田(Yun-Tien Chen)

指導教授 ： 高慧玲

中原大學/工學院/電子工程研究所/碩士(2006年)

https://doi.org/10.6840/cycu200600205

摘要

本論文描述表面聲波(surface acoustic wave, SAW)感測器之感測機制，以及SAW濕度感測器之製作與量測。並以聚乙烯醇(polyvinyl-alcohol , PVA)薄膜材料塗佈於在表面聲波共振器之壓電基板，製作濕度感測器並研究其感測能力。
我們量測表面聲波濕度感測器之相對濕度對中心頻率和插入損失的影響，量測範圍從30 至90%的相對濕度，當聚乙烯醇薄膜厚度在3000Å，我們獲得中心頻率差有1517 KHz、插入損失差有-10.31dB的變化範圍。另外，我們也研究該感測器之水氣吸收與去吸附的短期再現性、磁滯(hysteresis)性與老化(aging)速率之特性。
實驗結果顯示聚乙烯醇薄膜具有一個良好濕度感測性質，能提供表面聲波濕度感測元件應用在較高的相對濕度環境之感測。

關鍵字

聚乙烯醇薄膜 ； 濕度感測器 ； 表面聲波共振器

並列摘要

The thesis describes the sensing mechanism, the fabrication and the measurements of the SAW humidity sensors. Highly sensitive SAW humidity sensors were fabricated by spin-coating polyvinyl-alcohol (PVA) thin film onto piezoelectric substrate of the SAW resonators.
The transmission properties of the SAW sensor, including center frequency and insertion loss were studied at a relativity humidity ranging from 30 to 90%. Frequency deviation of 1517 KHz and insertion loss deviation of –10.31 dB were obtained when the PVA thin film thickness was increased to about 3000 Å in the variation of relative humidity.
In the other hand, the short-term repeatability, the hysteresis properties and aging rate of water absorption and desorption cycle have been examined. The results have justified the suitability for the PVA film coated SAW resonators in the application of sensing humidity at a higher relative humidity.

並列關鍵字

SAW resonator ； humidity sensor ； PVA thin film

參考文獻

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