Transcript 投影片 1

2012 INTERNATIONAL SYMPOSIUM ON NANO SCIENCE AND TECHNOLOGY
Tainan, TAIWAN, 8-9 November 2012
THE STUDY OF NON-CONTACT SENSOR
EXPERIMENT ON PHANTOM
Hung-Chi Yang*, Tsung-Fu Chien, Rui-An Chang, Yu-Ming Chen
Abstract
Department of Electrical Engineering, Southern Taiwan University, Tainan, TAIWAN
E-mail: [email protected]
The purpose of this study is to design a non-contact capacitive sensor. It will not cause the patient's discomfort due to
traditional electrode adhesive, and thus enhance the quality of medical care. The structure of the electrode is concentrical foil on one
side and the other surface is the detection circuit which can convert physiological signals. The study purposed the simulation way to
confirm the capability of the non-contact capacitive sensor. Two copper plates embedded into two sides of a piece of pork are
connected the physiological simulation signal. Then the propsed capacitance electrode measured this signal on the pork separated by
the cotton. This study exhibited the way can detect clearly the simulation signals form the phantom.
Experimental
The electrode is made of FR4 board. Its one side surface is concentric foil close to the cotton, and the other side is detection
circuit. The radius of the outer ring foil is 20 mm, and the radius of inner circle foil is 9.5 mm. The gap between these two foils is 3
mm (Figure 1). The two foils are respectively connected to the amplifier circuit of Sc shown in Figure 2. Two copper plates
embedded into two sides of a piece of pork are connected the physiological simulation signal which is 1 Hz square wave (Figure 3).
Then the proposed capacitance electrode measured this signal on the pork separated by cotton shown in Figure 4. Moreover, Vc
supplies 500 Hz sine wave for carrier wave.
Results and Discussion
When the electric field of simulation signals (square wave) which are 10 mVpp, 100 mVpp, 500 mVpp, 1 V are applied into
the pork respectively, the signals measured from the proposed capacitance electrode separated by cotton are shown in Figure 5
respectively. Notice that these signals has been filtered out the 500 Hz carrier wave. it is very clear that the proposed sensor can take
out the similar signals from physiological tissue by noncontact method. And the applied voltage does not affect the sensitivity of the
output value.
Conclusion
This study proposed an innovative sensor. This sensor is placed on the surface of cotton cloth, and human body electrical
signals can be measured. It improves the inconvenience of traditional adhesive electrodes to the patients and increases health human
resources. During this study, we figure out that the signal measured by non-contact sensor is easily affected by the electrostatic effect,
adhesiveness, and the position of measurement. Overall, the study of non-contact capacitive sensor is able to measure the potential
signals of organism and the applied voltage does not affect the sensitivity of the output value.
References
[1] Y. B. Jing Zhang, D. Shen, L. Wen, C. Ding, Z. Cui, F. Tian, B. Yu, B. Dai, and J. Zhang, “A portable ECG and blood pressure
telemonitoring system,” IEEE Engineering in Medicine and Biology Magazine, vol. 18, no. 4, pp. 63-70, 1999.
[2] Akinori Ueno, Yasunao Akabane, Tsuyoshi Kato, Hiroshi Hoshino, Sachiyo Kataoka, and Yoji Ishiyama, “Capacitive Sensing of
Electrocardiographic Potential Through Cloth From the Dorsal Surface of the Body in a Supine Position: A Preliminary Study,”
IEEE TRANSACTIONS ON BIOMEDICAL ENGINEERING, VOL. 54, NO. 4, APRIL 2007.
Figure 1. The electrode.
Figure 2. Detection circuit.
(a)
Figure 4. Electrode measurement location.
Figure 3. Pork Size.
(b)
(d)
(c)
Figure 5. the signals measured by the proposed sensor, as simulation signals (square wave) in pork is
(a)10 mVpp, (b)100 mVpp, (c)500 mVpp, (d)1 Vpp.