Hugues Lebrun

15.4: Invited Paper: Design of integrated Drivers with Amorphous Silicon TFTs for Small Displays. Basic Concepts

In this paper we shall review the basis for the design of integrated circuits with amorphous silicon TFTs on glass, first by the analysis of the TFT reliability then by the use of the reliability data to optimise the circuits design.

AMLCD with integrated drivers made with amorphous-silicon TFTs

An active matrix LCD with integrated drivers was developed using a standard amorphous silicon TFT technology. Despite the low mobility, the high threshold voltage and high parasitic capacitance of this technology compared to polysilicon technologies, we have built an high performance light valve for projection application. We shall discuss the topology and the main features of the integrated row and column drivers and the matrix.

Threshold-voltage drift of amorphous-silicon TFTs in integrated drivers for active-matrix LCDs

The threshold-voltage drift of a-Si TFTs for AMLCD integrated drivers was studied. Analysis of the drift shows two different kinetics. Both charges trapped in the insulator and defect generation in the a-Si layer occur simultaneously. However, after a period of time charge trapping in the insulator becomes predominant.

22.3: A 3.4-inch Reflective Colour Active Matrix Liquid Crystal Display without Polarisers

A 3.4″ reflective colour AMLCD was developed using the standard a-Si:H TFT technology and a vertically aligned dyed cholesteric liquid crystal mixture. Optimised liquid crystal mixture, de-saturated colour filters and high pixel aperture ratio were achieved in order to demonstrate a high reflectivity with an acceptable contrast ratio in a large viewing cone.

2D numerical simulation of a-Si:H TFTS: Application to parasitic contact resistances evaluation

Abstract In this paper, we present a 2D numerical computer program for amorphous silicon thin film transistors (a-Si:H TFTs) simulation, and its application to the bidimensional study of the parasitic channel access resistances. The program solves the transport equation set under non-equilibrium steady state conditions, for given applied voltages. The values of physical parameters describing the internal state of the transistor are calculated at each node of a bidimensionnal mesh and the resulting drain current can therefore be related to the physical characteristics of the materials and to the geometrical and technological parameters of the device. The program allowed us to perform the evaluation of parasitic channel access resistances and their sensitivity to physical and geometrical parameters.

7.2: A 4.3-inch Full-colour a-Si:H TFT Active Matrix Liquid Crystal Display with 312 ppi

A 4.3″ full-colour AMLCD with a density of 312 pixels per inch was developed using a standard a-Si:H TFT technology. This display is compatible with high definition professional monitors and more precisely for collimated head display applications in term of transmission, reflectivity, viewing angle, colour purity and automotive environmental conditions.