| Summary: | 博士 === 國立交通大學 === 電機工程學系 === 106 === 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.
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