Browsing by Author "Shieh, Yi-Chueh"

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A Novel Suspension Design for MEMS Sensing Device to Eliminate Planar Spring Constants Mismatch
(2012)
Jiang, Kai-Yu
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Chen, He-Ling
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Hsu, Wensyang
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Lee, Yueh-Kang
;
Miao, Yen-Wu
This paper presents a new suspension design for planar MEMS sensing devices. The new design includes four coil springs which are symmetrically arranged with respect to the center of the proof mass with 90-degree orientation difference. The proposed coil spring design is found to take less area to achieve similar spring constant than the conventional serpentine spring design. Furthermore, the proposed symmetrical-to-center arrangement on suspension can reduce spring constants mismatch between X and Y axes, even under beam width deviation due to fabrication resolution. This concept is realized and verified by experimental results from two-axis capacitive accelerometers through a polysilicon-based CMOS fabrication platform.
A Rapid Fatigue Test Method on Micro Structures for High-Cycle Fatigue
(2016-03)
Shieh, Yi-Chueh
;
Lin, Hsuan-Yu
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Hsu, Wensyang
;
Lin, Yu-Hsin
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機械工程學系
Here, a rapid fatigue test method for micro structure is proposed, where the test sample is excited at its resonant frequency by an external actuator. Due to the scaling effect, a micro cantilever beam has high resonant frequency, so the testing time can be greatly reduced. In addition, no complicated built-in micro actuator is needed; therefore, it is easy to fabricate the test sample. Single-crystal silicon (SCS) beams are fabricated to demonstrate the proposed method here with two types of beams. A notch is designed near the fixed end to have stress concentration effect. The input voltage of the piezoelectric patch is adjusted to excite the cantilever beams at its resonant frequency to have different amplitudes to find the corresponding fatigue life, where a laser Doppler vibrometer is used to monitor displacements of the cantilever beam to control the stress amplitude. Then, the stress-life (S/N) curve of the silicon beam can be obtained. It is found that the fatigue limit of the SCS beam is about 1.33 GPa, and it takes only about 5.2 h to test 1.35 x 10(9) cycles at a resonant frequency of 72 kHz. Comparing with previous fatigue test methods with an external probe, testing 10(9) cycles at a frequency of 20 Hz will need 1.58 years, which indicates that the proposed rapid fatigue test method is particularly suitable for high-cycle fatigue test of micro structure.
A Resettable, Wireless and Passive Fall-Down Recorder Using a Magnetic Droplet With an LC Circuit
(2016-02-01)
Huang, Cheng-Yeh
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Sun, Peng
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Lee, Meng-Shiue
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Wu, Sung-Yueh
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Shieh, Yi-Chueh
A fall-down recorder can record the happening of an object falling down during object delivery or transportation, even after the object is recovered to its initial state. Here, a resettable, wireless and passive fall-down recorder is proposed by integrating a droplet-based inertial force switch with the inductor-capacitor (LC) circuit for wireless signal transmission. A magnetic droplet is used in the switch with a converging microchannel to control the desired threshold acceleration. When the inertial force exceeds the designed threshold acceleration, the magnetic droplet will pass through the converging microchannel to a deep cavity to become a different state. By connecting the switch with the sensing LC circuit, the state of the recorder can be wirelessly identified through the LC resonant frequency. After triggering, this switch can be remotely reset to its initial state by an external magnet. A proper hydrophobic surface treatment is employed to facilitate the movement of the magnetic droplet and reduce the variation on the threshold acceleration. The capabilities, including switching, recording, wireless reading, and resetting of the proposed fall-down recorder, are successfully designed, fabricated, and verified with ten recording-reset tests.
A Reversible Micro Mechanical-latch Shock Switch by External Magnetic Field
(2012)
Shieh, Yi-Chueh
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Ma, Ruei-Pin
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Hsu, Wensyang
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Lin, Yu-Hsin
;
Tang, Yu-Hsiang
A reversible passive micro mechanical-latch shock switch made of nickel is designed, fabricated, and tested here. Unlike previous reversible mechanical-latch shock switches, which need built-in micro actuators to unlock the latch, the design proposed here utilizes external magnetic field to unlock the switch after experiencing impact over threshold level. Therefore, the switch is reusable and compact due to no built-in micro actuator.
Simultaneous detection of two growth factors from human single-embryo culture medium by a bead-based digital microfluidic chip
(2020-02-15)
Lee, Meng-Shiue
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Hsu, Wensyang
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Huang, Hong-Yuan
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Tseng, Hsueh-Yang
;
Lee, Chia-Tung
The measurement of growth factors released in a culture medium is considered to be an attractive non-invasive approach, apart from the embryo morphology, to identify the condition of an embryo development after fertilization in vitro (IVF), but the available embryo culture medium in the current method is only a few microlitres. This small sample volume, also of small concentration, makes difficult the application of a conventional detection method, such as an enzyme-linked immunosorbent assay (ELISA). A reliable detection of the growth factor from each embryo culture medium of such a small concentration hence remains a challenge. Here for the first time we report the results of measurement of not just one, but two, growth factors, human IL-1 beta and human TNF-alpha, from an individual droplet of embryo culture medium with a bead-based digital microfluidic chip. The required sample volume for a single measurement is only 520 nL; the total duration of the on-chip process is less than 40 min. Using the culture media of human embryos with normal morphologic features, we found that the concentrations of TNF-alpha change little from day 3 to day 5-6, but the concentrations of IL-1 beta for some embryos might double from day 3 to day 5-6. For other embryos even with similar normal morphologic features, some growth factors, such as IL-1 beta, might exhibit different expressions during the culture period. Those growth factors could serve to distinguish the development conditions of each embryo, not merely from an observation of embryo morphology.