An electroluminescent display simulation system and its application for developing grey scale driving methods: Dissertation

A simulation system was developed for thin film alternative current driven electroluminescent displays. The model embraces the whole display unit: the luminating panel, the row and column drivers and the pulse generator circuits. An electro-analog model is constructed for the luminating element and the luminating matrix panel. Macromodels suitable for system simulations were developed for the drivers and parameters for them were extracted from actual integrated driver circuit processes. The pulse generators were modeled mainly by utilizing standard circuit simulator component models. The system was verified by simulating on-off type displays and comparing the results with measured ones. The simulation system was applied for studying various proposed gray scale driving methods for thin film electroluminescent displays. It was found that with present display manufacturing parameters most driving methods do not provide more than 16 levels with acceptable accuracy. It is concluded that the way to a higher number of levels is either in the reduction of the electrode time constants or in developing more sophisticated gray scale driving schemes. An advanced current mode driving schema was developed to overcome the problems of the basic methods. In simulations the schema showed good performance and accuracy for up to 64 levels.