臺灣博碩士論文加值系統

近年來，平板顯視觸控輸入應用領域，利用非晶矽薄膜電晶體當作光感側元件的應用及發展越來越多元化。於配合主動式液晶顯示器的應用上，通常需要外部多加元件，此如電阻式、電容式 或是電感式的觸控平板元件。這不僅增加元件的材料成本，也相對的影響顯示器的光穿透效率。但若是搭配內建於顯示器的被動式感應電路來使用，則可省去外部多加元件，並可大幅提昇透光度及解析度。此設計為利用平面顯示器前段製程技術，將光感側元件製作在每一個影像畫素中，利用相同於驅動液晶的非晶矽薄膜電晶體，來當感測光信號的元件。此時每一個光信號將可透過光感測電晶體而儲存下來，再經由循序的電路定址，輸出所要的信號，即可達到讀取的功能。
在作法上，光感測元件除可做成主動式外，若以被動式來做，則可提高製作密度。此類似我們過去所瞭解的1T-DRAM作法，可將DRAM容量提高數倍。以單一個電晶體當成單一像素，亦可提高感測解析度。此為被動式像素感應器相對於主動式像素感應器優點之一。另外，被動式像素感應器的作法，可於範圍內提高胞體 (Cell) 的密度，如此以有更高密度的顯示像素，亦可提高其矩陣顯示像素的量子效率。
過去在許多重要的研究報告，明確顯示被動式像素感應器的主要缺點在於電路中的寄生電流。因為它會導致矩陣顯示像素所產生信號的改變。本篇論文中將探討以HSPICE為模擬的工具，來並且模擬矽薄膜電晶體被動式像素感應器各項參數的變化，於本研究中的結果顯示出光感應電流於小至10-12 ~ 10-15 A均可有效的將訊號傳送出，而不會受到電路中的寄生電流的影響，而使訊號產生改變。
依據本論文模擬的結果，若能實際的應用在產品中，若其結果亦能與模擬結果相近，則將可大大的提高被動式像素感應器在矽薄膜電晶體光感測元件的應用，相信不久將來，會有更寬廣、更多采多姿的消費性產品，採用被動式像素感應器來製作。

Recently, new imaging devices that take advantage of the TFT array have been developed in the non-display field. The majority of touch-enabled AMLCDs , active matrix liquid crystal display, are based on resistive, capacitive or inductive touch technology. All these solutions require externally added components or screens, which add cost and reduce optical performance. If we can match the passive pixel sensor circuit and use them on the medical image, we can promote the detection rate of the disease by a wide margin. In this way, a photodiode can be integrated into each pixel of the TFT array, or a photoconductive layer can be formed on the TFT array. Thus, the electric charge generated in the photo-detective can be stored in the pixel, depending on the outside of light signals. Then, the charge intensity information can be read out as the imaging data by sequential line-addressing.
Passive pixel sensors provide an alternative to the conventional Active Pixel Sensor (APS) for high-density CMOS imaging arrays. Similar to the history of the single-transistor DRAM cell, this one-transistor pixel cell boasts one main advantage over the APS. It can achieve a high fill-factor in a smaller area, leading to a high density array of pixels with high quantum efficiency.
Learn in the reports of several experiments, a major weakness in passive pixels is a signal-dependent parasitic current that can contaminate charge signals in different parts of the array. In this thesis we use HSPICE as the tool, and simulate several important parameters in passive pixel sensor circuit in amorphous Si TFT. The simulation result in the thesis demonstrates that, with the photo sensor current as small as 10-12 to 10-15 (A), the signal is not influenced by parasitic current in the circuit and can be conveyed out without deterioration.
According to the result of our study, if it can be practically applied to the products design, and if the result is good, we believe that the application of passive pixel sensor with amorphous Si TFT will move a big step forward and be adopted to use widely in different consumer products.

Chinese abstract
English abstract
Acknowledgement
Contents
List of Figures
Chapter 1 Applications of a-Si & poly-Si TFT photo sensor array
1-1 Introduction
1-2 Overview of Low Temperature Poly-Silicon Thin Film Transistor (LTPS TFT) Technology
1-3 Flat panel Imager using a-Si TFT Array - SHARP Corp.
1-3-1 Device configurations
1-3-2 Device sequence and performance
1-4 Active Matrix LCD with Integrated Optical Touch Panel–Planar system
1-4-1 Photocurrent in a-Si TFTs
1-4-2 TFT LCD with embedded sensor and operation circuit
1-5 Fingerprint Scanner Using a-Si:H TFT Array–LG. Philips LCD Co.
1-5-1 Introduction of fingerprint
1-5-2 Circuit and TFT performance
1-6 Amorphous Silicon Phototransistor n-i-p-i-n for Name Card Reading – Kyunghee University,Korea
1-6-1 Introduction of card reader
1-6-2 I-V characteristics and performance
1-7 TFT Arrays for Direct-Conversion X-Ray Sensors and High-Aperture AMLCDS – OIS Optical Imaging Systems
1-7-1 Introduction of flat panel X-ray detector
1-7-2 X-ray detector structure
Chapter 2 Photo detector of Amorphous Si TFT Introduction
2-1 CMOS Passive and Active Pixel Sensors
2-2 Passive pixel sensor circuit operation introduction
2-2-1 Comments on Operation
2-2-2 PPS Charge to Output Voltage Transfer Function
2-2-3 PPS Readout Speed
2-3 Active pixel sensor circuit operation introduction
2-3-1 Comments on Operation
2-3-2 APS Charge to Output Voltage Transfer Function
2-3-3 APS Readout Speed
Chapter 3 HSPICE Simulation tooling and Modeling introduction
3-1 HSPICE simulation tool introduction
3-1-1 Hspice Applications
3-1-2 Star-Hspice Features
3-2 Amorphous Silicon TFT modeling
3-2-1 Equivalent Circuit & Parameters
3-2-2 Model Equations
3-3 Poly Silicon TFT modeling
3-3-1 Equivalent Circuit & Parameters
3-3-2 Model Equations
3-4 Passive pixel sensor circuit modeling
Chapter 4 Simulation Result
4-1 Amorphous Silicon TFT Simulation
4-2 Poly Silicon TFT Simulation
4-3 PPS With a-Si TFT Simulation
4-4 PPS With poly-Si TFT Simulation
4-5 Actual Sample Fitting Simulation
Chapter 5 Conclusion
5-1 Conclusion
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