Abstract: A resonant mode energy recovery circuit is disclosed for supplying drive pulses to an electroluminescent (EL) display arranged as a matrix of pixels addressed by a plurality of column and row electrodes. An external inductor is used to alternately store and supply energy from the column electrodes of the EL display which has an impedance equivalent to an array of capacitors and resistors. Switching transistors and diodes are used to start and stop the resonant current flow at 1/4 wavelength intervals of the resonant frequency of the resonant tank formed by the external inductor and the array capacitors coupled to the column electrodes in order to form the pulses required to address the columns of the matrix. Switched current sources are used to start and stop nonresonant current flow to form the refresh and write pulses used to form the pulses required to address the rows of the matrix.

Abstract: An apparatus for essentially eliminating variations in luminescence (i.e., inverse shadowing) in an electroluminescent (EL) display is disclosed. The pixels of an EL display are driven to their light emitting voltage with a signal having a rise time dv/dt at and above the pixel light emitting threshold voltage which is independent of the number of pixels ON in each display row. The result is that each ON pixel in the display exhibits substantially the same luminescence.