Browsing by Author "Wu, Chin-Cheng"

Now showing 1 - 7 of 7

A Cost-Effective Angle Demodulator IC for Path Matched Differential Interferometry Based Sensors
(2014)
Hong, Hao-Chiao
;
Chen, Yun-Tse
;
Hung, Shao-Feng
;
Wu, Chin-Cheng
;
Chiu, Yi
The angle demodulator (ADM) is a key component for the path matched differential interferometry (PMDI) sensors. Conventional ADMs require tens of operational amplifiers (OPAMPs) and bulky capacitors and resistors, making them diflicult to be realized as integrated circuits (ICs). This paper presents the first ADM IC design that requires only one OPAMP and thus saves significant area and power. In addition, this novel ADM design tolerates a wide range of modulation depth of the optical interferometer of the PMDI sensors. As a result, the yield of the PMDI sensor significantly increases. A test chip has been designed and successfully verified in 0.18-mu m CMOS. The active area of the proposed circuits is only 476 by 368 mu m(2) and it consumes only 6.26 mW.
A Wearable and Wireless Gas-Sensing System Using Flexible Polymer/Multi-Walled Carbon Nanotube Composite Films
(2017-09-01)
Chiou, Jin-Chern
;
Wu, Chin-Cheng
;
電子工程學系及電子研究所
;
電控工程研究所
;
Department of Electronics Engineering and Institute of Electronics
In this study, an integrated flexible gas sensor was developed based on a polymer/multiwalled carbon nanotube composite film by using Bluetooth wireless communication/interface technology. Polymer/multi-walled carbon nanotube composite films were deposited over a polyimide flexible substrate for building a gas sensor array by using a drop-casting method. Sensor response was acquired through interdigitated electrodes and multi-channel sensor boards, which were linked to a Bluetooth wireless transceiver. Additionally, a double-spiral-shaped heater was built into the backside of the gas sensor array as a thermostat to protect it from the influence of ambient temperature. Multi-channel sensing responses were read on a display screen via a smartphone application (app). The advantages of this system include light weight, low cost, highly integrated sensors, wireless telecommunication, and real-time functioning. Thus, it is a promising candidate for deployment in a wearable gas-sensing system used to study air pollution.
An Angle Demodulator IC Using Periodically Reset Integration for Path Matched Differential Interferometry-Based Sensors
(2016-06-15)
Hong, Hao-Chiao
;
Chen, Yun-Tse
;
Hung, Shao-Feng
;
Wu, Chin-Cheng
;
Chiu, Yi
The angle demodulator (ADM) is a key component for sensors based on angle modulation such as in the path matched differential interferometry (PMDI). Conventional ADMs require tens of operational amplifiers (OPAMPs) and bulky capacitors and resistors, making them difficult to be realized as integrated circuits (ICs). Furthermore, the state-of-the-art ADMs demand precisely controlled modulation indices. Thus, the practical optical modulators in the interferometers cannot but need sophisticated and costly calibrations to precisely control the modulation indices. This paper presents the first ADM IC designed for the PMDI-based sensors. It requires only one OPAMP and thus saves significant area and power, making it best suitable for portable applications. In addition, this novel ADM design tolerates a wide range of the modulation depth of the optical interferometer. As a result, the yield of the PMDI sensor significantly increases and no calibration for an accurate modulation index is necessary. A test chip of the proposed ADM has been designed and successfully verified in 0.18-mu m CMOS. The active area of the proposed circuits is only 476 x 368 mu m(2) and it consumes only 6.26 mW.
Effects of Operating Temperature on Droplet Casting of Flexible Polymer/Multi-Walled Carbon Nanotube Composite Gas Sensors
(2017-01-01)
Chiou, Jin-Chern
;
Wu, Chin-Cheng
;
Huang, Yu-Chieh
;
Chang, Shih-Cheng
;
Lin, Tse-Mei
This study examined the performance of a flexible polymer/multi-walled carbon nanotube (MWCNT) composite sensor array as a function of operating temperature. The response magnitudes of a cost-effective flexible gas sensor array equipped with a heater were measured with respect to five different operating temperatures (room temperature, 40 degrees C, 50 degrees C, 60 degrees C, and 70 degrees C) via impedance spectrum measurement and sensing response experiments. The selected polymers that were droplet cast to coat a MWCNT conductive layer to form two-layer polymer/MWCNT composite sensing films included ethyl cellulose (EC), polyethylene oxide (PEO), and polyvinylpyrrolidone (PVP). Electrical characterization of impedance, sensing response magnitude, and scanning electron microscope (SEM) morphology of each type of polymer/MWCNT composite film was performed at different operating temperatures. With respect to ethanol, the response magnitude of the sensor decreased with increasing operating temperatures. The results indicated that the higher operating temperature could reduce the response and influence the sensitivity of the polymer/MWCNT gas sensor array. The morphology of polymer/MWCNT composite films revealed that there were changes in the porous film after volatile organic compound (VOC) testing.
Flexible Polymer/Multi-walled Carbon Nanotube Composite Sensor Array Equipped with Microheater for Gas Sensing
(2016)
Wu, Chin-Cheng
;
Chiou, Jin-Chern
;
Wang, Yu-Ping
;
Wang, Li-Chun
;
電機工程學系
A polymer/multi-walled carbon nanotube (MWCNT) composite sensor array based on a flexible polyimide substrate equipped with a thermostatic microheater to provide different working temperatures was developed for gas sensing. The thermostatic microheater provided nine working temperatures ranging from 20 degrees C to 60 degrees C. Each microheater element included a 3 x 3 polymer/MWCNT composite sensor array, which is composed of MWCNTs and polymer composite, as a sensing material. The device was developed to investigate the effect of device temperature on the response of polymer/MWCNT composite gas sensor arrays. The response to ethanol at different temperatures showed resistance variation but similar performance for the proposed gas sensor array.
Sensitivity Enhancement of Acetone Gas Sensor using Polyethylene Glycol/Multi-Walled Carbon Nanotubes Composite Sensing Film with Thermal Treatment
(2019-03-05)
Chiou, Jin-Chern
;
Wu, Chin-Cheng
;
Lin, Tse-Mei
;
電子工程學系及電子研究所
;
電控工程研究所
There is a need to develop a chemiresistive gas sensor equipped with a thermostat over a wide area for the sensor, which can protect the sensor from the influence of ambient temperature due to the uniform temperature of the thermostat. In this paper, we demonstrated an acetone gas sensor based on a polyethylene glycol (PEG)/Multi-walled Carbon Nanotubes (MWCNTs) composite film, which was equipped with a thermostat. The sensor was operated at modest working temperatures for sensor sensitivity enhancement. The optimum design of the polyimide-based thermostat with widely uniform thermal distribution was investigated in detail. It was found that the temperature uniformity of the thermostat was achieved using double spiral geometry. The experimental results of the sensor response showed that the PEG/MWCNTs composite film with a moderate working temperature revealed a higher sensitivity than that without thermal treatment. Moreover, the sensing mechanisms of the PEG/MWCNTs composite gas sensor to acetone vapor were studied as well.
The study of corrosion behavior of manganese-based conversion coating on LZ91 magnesium alloy: Effect of addition of pyrophosphate and cerium
(2020-07-01)
Jian, Shun-Yi
;
Tzeng, Yu-Chih
;
Ger, Ming-Der
;
Chang, Ko-Lun
;
Shi, Gia-Nan
A previous study by the authors reported that a Mn-Ce based conversion coating protects the surface of LZ91 magnesium alloy from corrosion. However, the acidic permanganate solution decomposes after several days of storage and this significantly affects the properties of the coating. To address this problem, this study presents a method to stabilize the acidic permanganate bath by adding pyrophosphate into the bath. The results show that all conversion coatings are amorphous and comprise two layers: a porous layer that contacts the substrate and a compact overlay. Coatings that are produced using a bath with Ce are more resistant to corrosion than those that are produced in a bath without Ce ions. Coatings that are stored in the Mn-Ce bath for 2 weeks are significantly less resistant to corrosion than coatings that are produced using an as-prepared Mn\\Ce bath. The salt spray test results of coatings that are produced using the as-prepared bath and stored for 2 weeks are found similar because the bath is rendered more stable by the addition of pyrophosphate. (C) 2020 The Authors. Published by Elsevier Ltd.