Browsing by Author "Chiu, Hao-Lin"

Now showing 1 - 6 of 6

Active matrix touch sensor detecting time-constant change implemented by dual-gate IGZO TFTs
(2012-06-01)
Tai, Ya-Hsiang
;
Chiu, Hao-Lin
;
Chou, Lu-Sheng
;
光電工程學系
;
顯示科技研究所
The dual-gate IGZO TFT is proposed to be used in an active matrix touch sensing circuit. The circuit contains only one TFT with a RC low-pass filter, since the dual-gate IGZO TFT can be controlled by both its top and bottom gates. The simplest structure maximizes the sensing pad area in the pixel. A touch event on the sensing pad forms a capacitance and thus increases the RC time-constant of the scan pulse fed to the gate of TFT. Thus, a significant transient ON current is generated to be the sensing signal. The current is so large that it can be easily read out and thus the power and cost of peripheral ICs can be reduced. In this paper, the robustness of the circuit to environment in operations is discussed. (c) 2012 Elsevier Ltd. All rights reserved.
Gap-Type a-Si TFTs for Front Light Sensing Application
(2011-12-01)
Tai, Ya-Hsiang
;
Chou, Lu-Sheng
;
Chiu, Hao-Lin
;
光電工程學系
;
顯示科技研究所
The photo effect of gap-gate type hydrogenated amorphous silicon thin-film transistor (a-Si:H TFT) has been studied to be employed as light sensors owing to its outstanding photosensitivity. It can be operated in on region to provide a higher current level as the sensing signal. However, the gap-gate a-Si:H TFT suffers from some problems such as the photo-current degradation resulted from illuminations and the disturbance of the backlight source when it is used as the sensor in display panel. A new method is proposed to overcome the above issues, which gives a feasible way for this kind of TFT to be used in TFT LCD panel. In this paper, the operation of the sensing method is fully described.
Large-Area Capacitive Active Touch Panel Using the Method of Pulse Overlapping Detection
(2013-03-01)
Tai, Ya-Hsiang
;
Chiu, Hao-Lin
;
Chou, Lu-Sheng
;
光電工程學系
;
顯示科技研究所
In this paper, we propose a novel active touch panel circuit using the RC time constant changes when the panel is touched to induce pulse overlapping. The transient ON current of the pixel thin-film transistor (TFT) is to be detected for the judgment whether panel is touched or not. The proposed circuit has many advantages, such as simple structure, multi-touch, low operating power, as well as significant current to be read out easily by low cost ICs. Especially, it provides excellent stability since the circuit is hardly influenced by variation of TFTs. Discrete TFTs are used to build the proposed circuit to verify its function and the function is further demonstrated in a 2-inch 9x9 array. The potential for large area applications is proven by simulating a 42-inch touch panel with proper assumptions.
Test and Analysis of the ESD Robustness for the Diode-Connected a-IGZO Thin Film Transistors
(2013-08-01)
Tai, Ya-Hsiang
;
Chiu, Hao-Lin
;
Chou, Lu-Sheng
;
光電工程學系
;
顯示科技研究所
In this work, wafer level TLP testing is applied to amorphous indium-gallium-zinc-oxide (a-IGZO) thin-film transistors (TFTs) to study the factors of their electrostatic discharge (ESD) robustness. Two kinds of TFTs with N2O and O-2 treatments are subject to the ESD test. It is found that the contact resistance of the TFTs, instead of the channel quality, dominates the ESD power for them to be damaged.
The Deterioration of a-IGZO TFTs Owing to the Copper Diffusion after the Process of the Source/Drain Metal Formation
(2012)
Tai, Ya-Hsiang
;
Chiu, Hao-Lin
;
Chou, Lu-Sheng
;
光電工程學系
;
顯示科技研究所
In this work, the influence of copper on amorphous type Indium-Gallium-Zinc-Oxide (a-IGZO) thin-film transistor's (TFTs) transfer curve is studied. The I-D-V-G curves of a-IGZO TFTs with source/drain in the structures of Cu/Ti and Ti/Al/Ti are compared. The results show that the copper greatly deteriorates the performance of the TFTs. The presence of the copper in the channel region of the device is verified by SIMS analysis. A Cu-dipping experiment is conducted by dipping devices into the solution of CuSO4 to confirm the role of copper in the deterioration of the ID-VG curves. The hypothesis is also verified through ATLAS device simulator. (C) 2012 The Electrochemical Society. [DOI: 10.1149/2.025206jes]
Three-Transistor AMOLED Pixel Circuit With Threshold Voltage Compensation Function Using Dual-Gate IGZO TFT
(2012-03-01)
Tai, Ya-Hsiang
;
Chou, Lu-Sheng
;
Chiu, Hao-Lin
;
Chen, Bo-Cheng
;
光電工程學系
In addition to the gate electrode at the bottom, a dual-gate amorphous InGaZnO4 thin-film transistor (TFT) has a secondary gate electrode on the top. The threshold voltage (Vth) of the TFT using the bottom gate in its normal operation can be controlled by the top gate. Based on this phenomenon, a simple circuit of active-matrix organic light-emitting diode using the top gate to compensate threshold voltage variation is proposed. This new pixel circuit uses only three TFTs and two capacitors. The validity of Vth compensation is verified experimentally.