The design and operating characteristics of a 1200-element ferroelectric-electroluminescent display

Abstract
A 1200-element matrix addressed ferroelectric-electroluminescent display has been built with doctor-bladed Pb0.99[(Zr0.50Sn0.50)0.86Ti0.14]0.98Nb0.02O3ferroelectric ceramic. Each display element comprises a diode and a three-cell ferroelectric control circuit which stores the video information and drives an associated electroluminescent cell. The characteristics of the three-cell circuit are described in terms of the pertinent properties of the doctor-bladed ceramic. A design procedure based on the properties of the ferroelectric and electroluminescent materials is given for determining the cell dimensions and the driving voltage needed to obtain a specified maximum brightness, transfer characteristic, and contrast ratio. The 6- by 8-inch display panel, driven from a vidicon camera source, has been operated with high reliability for approximately 40 hours spread over a year. Subjective tests have shown that satisfactory gray scale, moving images can be obtained which are comparable to those of a conventional TV receiver. The average power dissipated is 175 watts. The measured variation in the transfer characteristics and the highlight brightness (16 ± 4 fL) was found to be due primarily to variations in the ferroelectric coercive voltage. These variations are due to nonuniformities in thickness caused by differential shrinkage during the firing of the 60 doctor-bladed strips (4- by 0.5- by 0.003-inch nominal) used in the display. Techniques exist for reducing these variations.