The field of displays is still evolving. New principles and technological breakthroughs overcome earlier limitations. Electroluminescence appears on the threshold of significant changes, hence it is too early to set standards. The driving voltage is coming down, brightness and efficiency are increasing, and the color range is expanding. In this paper we review several developments that may lead to new EL devices: excitation by tunneling hot carriers, recombination of electron-hole pairs injected by pn junctions into wide bandgap materials, and the use of quantum wells to increase brightness and efficiency and to adjust the color by mechanical design rather than by chemical strategy (e.g. doping).