可穿戴設備和電子皮膚已成為我們日常生活中最先進的電子應用，且在近年來，柔性壓力感測器受到許多關注，它在健康監控、人機介面、人工智慧等方面，皆有潛在的應用。柔性壓力感測器實際應用中的關鍵因素是靈敏度。為了提高感測器的靈敏度，我們開發了一種新的多孔微圓柱結構與PDMS的複合結構作為感測器的介電層，相較於實心的柱狀與多孔平面的介電層結構，靈敏度可以提升約2倍。此外為了進一步提高靈敏度性能，我們在介電層中混合鈦酸鋇 (BT)，因為它具有超高的相對介電常數。該傳感器靈敏度高（7.847 kPa-1），檢測極限能小至0.2123 Pa。此外該傳感器還具有快速響應時間 (<20 ms) 和釋放時間 (<25 ms)。經過10000次沖擊後，感測器仍保持良好的耐用性，性能表現依舊保持在97%，且在首次與10000次撞擊測試後，都未出現明顯的遲滯效應，這表明傳感器的重複性良好。因此，本研究有助於提供高性能的靈活電容壓力傳感器。

Wearable devices and electric skin have become current state of art electronic applications in our daily life. The key factor in the practical applications of flexible pressure sensors is the sensitivity. To enhance the sensitivity of sensors, we develop a new composite structure of porous micro-cylinder structure with PDMS. Moreover, in order to further improve performance of sensitivity, we mix Barium titanate (BT) in dielectric layer, due to its ultrahigh relative permittivity. The sensor has great sensitivity (7.847 kPa-1), and very small detection limit (0.2123 Pa). Furthermore, the sensor also has rapid response time (<20 ms) and release time (<25 ms). After 10000 times impact, the sensor still sustains great durability and does not appear obvious hysteresis effect both in the first time test and 10000th test. This indicates the repeatability of sensor has in good condition. Hence, this study contributes flexible capacitive pressure sensors with high performance.

Chapter 1 Introduction.............................7
1.1 Motivation.................................7
1.2 Objective and working principle...........9
Chapter 2 Literature Review........................15
2.1 Types of flexible pressure sensors........16
2.1.1 Piezoelectric pressure sensors..........16
2.1.2 Piezoresistive pressure sensors.........18
2.1.3 Triboelectric pressure sensors..........21
2.1.4 Capacitive pressure sensors.............22
2.2 Flexible capacitive pressure review.........24
2.2.1 Micro-structured dielectric layer.......25
2.2.2 Porous PDMS dielectric layer............34
Chapter 3 Experiment procedure....................39
3.1 Fabricating the flexible pressure
sensor....................................40
3.1.1 Fabricating the electrode...............40
3.1.2 Fabricating the porous dielectric
layer...................................40
3.1.3 Fabricate the porous dielectric
layer with barium titanate..............41
3.1.4 Assembling..............................42
3.2 Electromechanical Characterization..........43
Chapter 4 Preliminary Results.....................45
4.1 Characterization of Sensor..................45
4.2 Performance of Sensor.......................47
4.2.1 Finite Element Analysis.................47
4.2.2 Sensitivity of Sensor...................49
4.2.3 Detection Limit of Sensor...............53
4.2.4 Response and Release Time of
Sensor..................................55
4.2.5 Durability of Sensor....................56
4.3 Application of Sensor.......................59
4.3.1 Tactile Sensing.........................59
4.3.2 Health Caring...........................59
Chapter 5 Conclusion an future work...............62
5.1 Conclusion..................................62
5.2 Future work.................................63
References.........................................65

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