Browsing by Author "Yeh, Guan-Ting"

Now showing 1 - 7 of 7

A capacitor-based sensor and a contact lens sensing system for intraocular pressure monitoring
(2016-01-01)
Chiou, Jin-Chern
;
Huang, Yu-Chieh
;
Yeh, Guan-Ting
;
電機資訊學士班
;
電控工程研究所
This study proposes a capacitor-based sensor on a soft contact lens for the measurement of intraocular pressure (IOP). The sensor was designed and fabricated via microelectromechanical system fabrication technologies. The soft contact lens is designed to be worn on a cornea such that the curvature of the contact lens corresponds substantially to that of the cornea. In addition, the contact lens was fabricated via a cast-molding method using poly-2-hydroxyethyl methacrylate to achieve a lens with high oxygen permeability, which can be worn comfortably for a long time. An IOP sensor prototype was implemented, which exhibited 1.2239 pF mmHg(-1) (13,171 ppm mmHg(-1)) sensitivity during measurements of an artificial anterior chamber at pressures between 18 and 30 mmHg. The results indicate that the developed capacitor-based IOP sensor exhibited high stability and reproducibility in a series of measurements performed under various pressures. The capacitance of the proposed IOP sensor can successfully be converted into a digital value via a capacitor-to-digital converter and be transmitted via a commercial wireless telemetry system in this study.
A Contact Lens Sensor System with a Micro-Capacitor for Wireless Intraocular Pressure Monitoring
(2013)
Huang, Yu-Chieh
;
Yeh, Guan-Ting
;
Yang, Tzu-Sen
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Chiou, Jin-Chern
;
電控工程研究所
This paper proposes a novel micro-capacitor sensor for intraocular pressure (IOP) measurement on soft contact lens. The sensor was designed and fabricated by using MEMS fabrication technologies. The contact lens is for wearing on a cornea such that a curvature of the contact lens corresponds substantially to that of the cornea, and is preferably made of Hydroxyethylmethacrylate (HEMA) by cast-molding method of soft contact lens for high oxygen permeability and comfortable long-duration wearing. The prototype without wireless antenna has been implemented with a sensitivity of 0.43 pF/mmHg in measurement of human eye like balloon pressure test between 100 mmHg and 180 mmHg. The results show its high stability and reproducibility in a series of repeatable pressure variation. In future work the micro-capacitor will be tested on enucleated porcine eyes with better and integrated with a radio frequency integrated circuit and antenna on soft contact lens so that IOP value could be transferred to voltage value via capacitor to voltage converter and transmits IOP sensing signal by wireless telemetry system.
A Wirelessly Powered Smart Contact Lens with Reconfigurable Wide Range and Tunable Sensitivity Sensor Readout Circuitry
(2017-01-01)
Chiou, Jin-Chern
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Hsu, Shun-Hsi
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Huang, Yu-Chieh
;
Yeh, Guan-Ting
;
Liou, Wei-Ting
This study presented a wireless smart contact lens system that was composed of a reconfigurable capacitive sensor interface circuitry and wirelessly powered radio-frequency identification (RFID) addressable system for sensor control and data communication. In order to improve compliance and reduce user discomfort, a capacitive sensor was embedded on a soft contact lens of 200 mu m thickness using commercially available bio-compatible lens material and a standard manufacturing process. The results indicated that the reconfigurable sensor interface achieved sensitivity and baseline tuning up to 120 pF while consuming only 110 mu W power. The range and sensitivity tuning of the readout circuitry ensured a reliable operation with respect to sensor fabrication variations and independent calibration of the sensor baseline for individuals. The on-chip voltage scaling allowed the further extension of the detection range and prevented the implementation of large on-chip elements. The on-lens system enabled the detection of capacitive variation caused by pressure changes in the range of 2.25 to 30 mmHg and hydration level variation from a distance of 1 cm using incident power from an RFID reader at 26.5 dBm.
Design and Fabricate a Contact Lens Sensor with a Micro-Inductor Embedded for Intraocular Pressure Monitoring
(2012)
Tseng, Chien-Kai
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Huang, Yu-Chieh
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Tsai, Shang-Wei
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Yeh, Guan-Ting
;
Chang, Chung-Hao
This paper presents a new type of micro-inductor sensor for intraocular pressure (IOP) measurement on soft contact lens substructure. The sensor was designed and fabricated by using MEMS fabrication technologies. The contact lens is for wearing on a cornea such that a curvature of the contact lens corresponds substantially to that of the cornea, and is preferably made of Hydroxyethylmethacrylate (HEMA) by cast-molding method of soft contact lens for high oxygen permeability and comfortable long-duration wearing. In this paper, we discuss a contact lens with micro-inductor measurement principle followed by a brief description of our sensor design and fabrication. Our first prototype without wireless has been tested in lab-simulation bench. We obtain a simulation and measurement results have good linearity between micro-inductor radius variation and oscillation frequency. In future work will be to optimize the fabrication technology and the design to reach a better resolution, also a radio frequency integrated circuit (RFIC) and antenna will be designed preferably embedded in the contact lens so that inductance value transfers to frequency value via LC oscillator circuit and transmits intraocular pressure sensing signal by wireless telemetry system.
Toward A Wireless Contact Lens Sensor System with a Micro-Capacitor for Intraocular Pressure Monitoring on in-vitro Porcine Eye
(2015)
Yeh, Guan-Ting
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Wu, Tsung-Wei
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Tsai, Shang-Wei
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Hsu, Shun-Hsi
;
Chiou, Jin-Chern
This work presents a type of capacitive sensor for intraocular pressure (IOP) measurement on soft contact lens with Radio Frequency Identification (RFID) module. The flexible capacitive IOP sensor and Rx antenna was designed and fabricated using MEMS fabrication technologies that can be embedded on a soft contact lens. The IOP sensing unit is a sandwich structure composed of parylene C as the substrate and the insulating layer, gold as the top and bottom electrodes of the capacitor, and Hydroxyethylmethacrylate (HEMA) as dielectric material between top plate and bottom plate. The main sensing principle is using wireless IOP contact lenses sensor (CLS) system placed on corneal to detect the corneal deformation caused due to the variations of IOP. The variations of intraocular pressure will be transformed into capacitance change and this change will be transmitted to RFID system and recorded as continuous IOP monitoring. The measurement on in-vitro porcine eyes show the pressure reproducibility and a sensitivity of 0.02 pF/4.5 mmHg
Toward a Wirelessly Powered On-Lens Intraocular Pressure Monitoring System
(2016-09)
Chiou, Jin-Chern
;
Hsu, Shun-Hsi
;
Liao, Yu-Te
;
Huang, Yu-Chieh
;
Yeh, Guan-Ting
This paper presents a wireless on-lens intraocular pressure monitoring system, comprising a capacitance-to-digital converter and a wirelessly powered radio-frequency identification (RFID)-compatible communication system, for sensor control and data communication. The capacitive sensor was embedded on a soft contact lens of 200 mu m thickness using commercially available biocompatible lens material, to improve compliance and reduce user discomfort. The sensor chip was shown to achieve effective number of bits greater than 10 over a capacitance range up to 50 pF while consuming only 64-mu W power. The on-lens capacitive sensor could detect dielectric variation caused by changes in water content from a distance of 2 cm by using incident power from an RFID reader at 20 dBm. The maximum detectable distance was 11 cm with 30-dBm incident RF power. The rise in eye tissue temperature under 30-dBm RF exposure over an interval of 1 s was simulated and found to be less than 0.01 degrees C.
Toward a Wirelessly Powered On-Lens Intraocular Pressure Monitoring System
(2016-09-01)
Chiou, Jin-Chern
;
Hsu, Shun-Hsi
;
Liao, Yu-Te
;
Huang, Yu-Chieh
;
Yeh, Guan-Ting
This paper presents a wireless on-lens intraocular pressure monitoring system, comprising a capacitance-to-digital converter and a wirelessly powered radio-frequency identification (RFID)-compatible communication system, for sensor control and data communication. The capacitive sensor was embedded on a soft contact lens of 200 mu m thickness using commercially available biocompatible lens material, to improve compliance and reduce user discomfort. The sensor chip was shown to achieve effective number of bits greater than 10 over a capacitance range up to 50 pF while consuming only 64-mu W power. The on-lens capacitive sensor could detect dielectric variation caused by changes in water content from a distance of 2 cm by using incident power from an RFID reader at 20 dBm. The maximum detectable distance was 11 cm with 30-dBm incident RF power. The rise in eye tissue temperature under 30-dBm RF exposure over an interval of 1 s was simulated and found to be less than 0.01 degrees C.