Browsing by Author "Tsai, Che-Hung"

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A New Active 3D Optical Proximity Sensor Array and Its Readout Circuit
(2013-01-01)
Chao, Paul C. -P.
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Hsu, Wei-Hsuan
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Tsai, Che-Hung
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電機工程學系
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Department of Electrical and Computer Engineering
A new hybrid fabrication process for a high sensitivity MEMS microphone
(2013-09-01)
Chao, Paul C. -P.
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Tsai, Chun-Yin
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Chiu, Chi-Wei
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Tsai, Che-Hung
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Tu, Tse-Yi
A novel multi-layer stacking capacitive type microphone is designed in this study based on theoretical analysis and numerical simulations, while fabricated via two standard stable silicon-based MEMS processes-PolyMUMPs and SOIMUMPs. The adoption of two standardized processes helps greatly to increase yield rate. The sensitivity of the microphone is first determined by an analytical model based on an equivalent circuit, which is followed by finite element (FEM) analyses on the capacitance value, static pull-in voltage and dynamic characteristics. Based on the developed analytical model, varied dimensions of the microphone are optimized and then the performance is validated by analytical simulations. In the next step, micro-fabrication of the microphone is accomplished using two standard processes, PolyMUMPs and SOIMUMPs provided by MEMSCAP. Experiments are conducted to acquire the information of pull-in voltage for safe operation and frequency response in sensitivity for performance evaluation. In the static case, experimental results show a good agreement with the analytical results with 90 Mpa residual stress assumed. As for dynamic validation, the frequency response is measured in an anechoic room adopting the exciting frequency as the audible range from 100-10 kHz. The measured sensitivity is as around 0.78 and 1.7 mV/Pa from 100 to 10 kHz, under the biases of 2 and 4.5 V, respectively. Within the audible frequency range, the proposed device maintains the loss as less as 2.7 dB (ref. to V/Pa), under 3 dB-the commonly acceptable drop within audible frequency range.
A Novel 3D Optical Proximity Sensor Panel and its Readout Circuit
(2010)
Lin, Tzu-Yang
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Chao, Paul C. -P.
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Chen, Wei-Dar
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Tsai, Che-Hung
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電子工程學系及電子研究所
This study presents a novel 3D optical proximity sensor (3D OPS) array panel. The panel is capable of detecting the objectives centimeters away from the panel surface. This device is composed of light-emitting diodes and home-made polymer photo-detectors (PPDs). The novel design of the circuit is the operation principle through active pixel circuit, sampling circuit, amplifier circuit and the decision of proposed chip parameters is determined by circuit simulation. The circuit is regarded low power and low cost as the design principle. The control sequence of the aforementioned circuit module is generated by an FPGA board to realize the operation of the whole circuit. The readout circuit is able to remove background current, and to detect the corresponding output voltage of photocurrent that is received by the PPD via reflections of the measured object. A human machine interface is built by LABVIEW to create 3D vision tracing of sensed object, validating the effectiveness of the 3D OPS.
An On-line Digital Optical Bench Tester Based on Conoscopy for Lens Quality Evaluation
(2013-01-01)
Hsu, Wei Hsuan
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Chao, Paul C. -P.
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Chen, Wei Dar
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Tsai, Che-Hung
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影像與生醫光電研究所
Design and realization of a high resolution (640 x 480) SWIR image acquisition system
(2014-08-01)
Chen, Jian-Ruei
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Chao, Paul C. -P.
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Tsai, Che-Hung
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Chen, Wei-Dar
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電機工程學系
A new image acquisition system module for extracting signals of high-resolution short wave infrared (SWIR) from a focal plane array (FPA) is presented in this study. The short wave infrared (SWIR-with wavelength about 900-1,700 nm) images have been proven its unique values in many applications such as military, semiconductor inspection and aviation security. The designs for the SWIR data acquisition system module consists of digitization and acquisition of FPA signals, design of synchronous dynamic random access memory controller and real-time image signal transformation and display. Three major steps involved towards a successful SWIR module-(1) Selection of hardware ICs according to specification for the FPA; (2) Design of a timing generator for the image acquisition system to control FPA and other ICs by Verilog HDL programming; (3) Integrate the individual modules on a PCB. The SWIR image output signals are successfully generated in the format of National Television System Committee (NSTC), which can be displayed on a common NTSC monitor, flat panel displays with an AV input terminal or a CRT display in a favorable speed of frame rate at 30 per second.
Design and Realization of High Resolution (640x480) SWIR Image Acquisition System
(2013-01-01)
Chao, Paul C. -P.
;
Chen, Jian-Ruei
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Tsai, Che-Hung
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Chen, Wei-Dar
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影像與生醫光電研究所
Optimal design and fabrication of ITO/organic photonic crystals in polymer light-emitting diodes using a focused ion beam
(2010-05-01)
Tsai, Che-Hung
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Liao, Lun-De
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Luo, Yi-Shiun
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Chao, Paul C. -P.
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Chen, En-Chen
This study aims to achieve high directionality and large extraction of light emission from polymer light-emitting diodes via optimizing photonic crystals (PCs). The optimization is achieved through the optical modeling using a 3D finite-difference time-domain (FDTD) method and the intelligent numerical optimization technique, genetic algorithm (GA). In results, the PC period, depth and filling factor can be found. The FDTD method has been proven very effective for modeling complex multilayer PLED devices in which the electron-transporting layer is only a few tens of nanometers away from a metallic layer. On the other hand, GA is a powerful tool to cope with a complicated optimization problem with multiple variables to optimize. The optimized PCs are later fabricated by focused ion beams (FIB) for the PLED. With desired PCs, an increase of the extraction efficiency in excess of 46% is achieved experimentally and the 3D FDTD calculation explains this result faithfully. (C) 2009 Elsevier B.V. All rights reserved.
Optimizing angular placements of the LEDs in a LCD backlight module for maximizing optical efficiency
(2013-09-01)
Chao, Paul C. -P.
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Tsai, Che-Hung
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Li, Jiun-De
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Chen, Wei-Dar
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影像與生醫光電研究所
This study aims to optimize angular placements of the LEDs with novel cone-shaped caps for achieving high optical efficiency in an ultra-thin, directly-lit RGB LED backlight unit (BLU) for large-sized LCD-TVs. This novel lens cap is used as a diffuser with the purpose to gain higher efficiency and provide satisfactory uniformity over a display panel. To this aim, the outer surface of the novel lens is coated with aluminum for mirroring effects to reflect most of the LED emitted light horizontally and then reflect the light at the BLU boundaries, finally to the output plane. Since the emitted white light from LEDs result from color-mixing of three individual RGB chips in a LED package, the addition of the LED cap however deteriorates the aforementioned expected color mixing. The optimal design on angular placements of LEDs presented in this study for satisfactory color-mixing and emission uniformity is achieved by necessary optics simulations via TracePro, followed by utilizing an intelligent numerical optimization technique, genetic algorithm (GA). The design parameters for GA optimization are different combinations of LED placement angles in a backlight module. Favorable color balance is shown achievable in terms of high low color difference resulted. Finally, experiments are conducted, which successfully validate the expected performance of color balance and emission uniformity for a novel cone-shaped LED lens with optimized angular placements in a large-area backlight module.