隨著行動多媒體裝置例如智慧型手機與平板的創新與迅速發展，人類的用眼習慣出現了大幅改變。因此，能夠長時間監控眼睛生理訊號的研究在過去幾年成為許多研究團隊的主要方向。青光眼以及乾眼症是兩種隨著用眼習慣改變常見的眼科疾病，本研究會以此兩種疾病的偵測與監控作為研究與開發的目標。
本研究提出一個用於長時間偵測眼睛生理訊號且可無線驅動之智慧隱形眼鏡系統。此智慧隱形眼鏡系統包含外部讀取器以及智慧隱形眼鏡。外部讀取器使用商用射頻識別(RFID)讀取器用以提供能量給智慧隱形眼鏡，並透過超高頻(UHF)射頻識別通訊協定EPCGlobal Class1 Gen2進行溝通。智慧隱形眼鏡由電容式或電阻式感測器、天線以及感測晶片所構成。隱形眼鏡中採用微機電製程(MEMS)製作的生物感測器來擷取眼睛的生理訊號，感測器隨著眼睛狀況的不同而將生理訊號轉換成阻抗變化。隱形眼鏡上的天線用來接收讀取器提供的能量並與讀取器進行無線通訊。感測晶片為一個基於射頻無線通訊並內嵌阻抗轉換器用以轉換眼睛生理訊號的積體電路晶片。眼睛生理狀況例如眼壓變化以及淚液蒸散速度透過生理感測器轉換成電容值或電阻值變化後，再經由阻抗轉換器轉換成數位訊號。此一數位訊號再依據射頻通訊協定經過編碼後透過阻抗調變回傳到外部讀取器。隱形眼鏡採用商用生物相容的水膠(HEMA)材料利用鑄模法將生物感測器、天線以及感測晶片整合於隱形眼鏡上。採用商用標準的200微米隱形眼鏡厚度以及標準的生產流程，可以降低本研究之隱形眼鏡的配戴不舒適感並提升使用者的使用意願。
本研究提出的智慧隱形眼鏡可以使用商用無線射頻讀取器在1公分的距離及26.5 dBm的發射功率下偵測2.25到30毫米汞柱的眼壓變化與隱形眼鏡的含水量變化。總結上述，本研究提出的智慧隱形眼鏡系統可以提供無線量測以及長時間監控的功能，未來藉由不同生物感測器的設計與整合可應用於其他生理訊號的偵測進而拓展應用領域。

Due to the invention and rapid development of multimedia devices such as smart mobile phone and tablet, people’s habits of using eyes have dramatically changed. Therefore, long-term monitoring of eye healthcare information attracts many research focuses in the past few years. Two major eye diseases, glaucoma and dry eye syndrome (DES), were used as illustrations for smart contact lens (SCL) developments in this research.
This research proposed a wirelessly powered smart contact lens sensor system for long-term monitoring of eye healthcare conditions. The SCL sensor system consists of SCL readout system and a smart contact lens. SCL readout system uses commercial radio frequency identification (RFID) reader to transmit energy to smart contact lens and communicates with it through ultra-high frequency (UHF) EPCGlobal C1G2 protocol. The smart contact lens consists of capacitive or resistive sensors, receiving antenna and sensor chip. The on-lens biosensors are fabricated with Microelectromechanical Systems (MEMS) technology to implement sensor devices for impedance variations following eye conditions. The receiving antenna is used for energy transmission and data communication. The sensor chip is a RFID based sensor chip with embedded impedance-to-digital converter (IDC) for sensor data conversion. The eye healthcare information such as intraocular pressure (IOP) and tear evaporation rate was detected by capacitance change of on-lens capacitive or resistive sensors. The digital value after conversion by IDC will be transmitted back to external RFID reader through load modulation. The chip, receiving antenna and biosensor were integrated on a soft contact lens with commercially available biocompatible HEMA hydrogel by using a general cast molding method. With standard 200-μm thickness and commercial manufacturing process, discomfort of proposed SCL is reduced and compliance is increased.
The proposed smart contact lens system enabled the detection of capacitive variation caused by pressure changes within the range of 2.25 to 30 mmHg and hydration level variation from a distance of 1 cm using 26.5 dBm incident power from commercial Gen2 RFID-compatible equipment. To sum up, the proposed SCL system can achieve wireless recording and long-term monitoring. The application of this system can be future extend by design and integration of different on-lens sensors for different biomarkers in the future.

摘要 I
ABSTRACT III
Acknowledgement/致謝 V
Table of Contents VI
List of Figures VIII
List of Tables XI
Chapter 1 Introduction 1
1.1 Background 1
1.2 Previous Work 1
1.2.1 Wireless Energy Harvesting 3
1.2.2 Sensor Readout Circuitry 4
1.3 Objectives 5
1.4 Organization 6
Chapter 2 Sensor Chip Design 8
2.1 Introduction 8
2.2 Chip Architecture 8
2.3 Analog Front End Circuitry 10
2.4 Digital Circuitry 17
2.5 Whole Chip Simulation and Verification 18
2.6 Summary 19
Chapter 3 Sensor Readout Circuitry Design 20
3.1 Introduction 20
3.2 Reconfigurable Impedance to Digital Converter 22
3.3 Summary 33
Chapter 4 Wireless Energy Harvesting 34
4.1 Introduction 34
4.2 Antenna Coupling and Power Scheme Optimization 35
4.3 Transmitting Antenna Design 36
4.4 Receiving Antenna Design 39
4.5 Antenna Coupling Simulation 40
4.6 Specific Absorption Rate Simulation 42
4.7 Summary 45
Chapter 5 Sensor Fabrication and Lens Package 46
5.1 Introduction 46
5.2 Sensor Design and Fabrication 46
5.3 Contact Lens Assembly Process 49
5.4 Summary 50
Chapter 6 Measurement Results 51
6.1 Introduction 51
6.2 Sensor Chip Front End Testing 51
6.2.1 Sensor Chip Functional Testing 52
6.2.2 Sensor Chip Front End Performance Testing 54
6.3 Sensor Readout Circuitry Measurement 56
6.4 Wireless Power Transfer Measurement 59
6.5 Smart Contact Lens System Measurement 62
6.6 Summary 66
Chapter 7 Conclusions and Future Work 67
7.1 Summary and Conclusions 67
7.2 Future Work 68
Reference 69

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