Displays based on inorganic light-emitting diodes (LED) are considered as the most promising one among the display technologies for the next-generation. The chip for LED display bears similar features to those currently in use for general lighting, but it size is shrunk to below 200 microns. Thus, the advantages of high efficiency and long life span of conventional LED chips are inherited by miniaturized ones. As the size gets smaller, the resolution enhances, but at the expense of elevating the complexity of fabrication. In this review, we introduce two sorts of inorganic LED displays, namely relatively large and small varieties. The mini-LEDs with chip sizes ranging from 100 to 200 μm have already been commercialized for backlight sources in consumer electronics applications. The realized local diming can greatly improve the contrast ratio at relatively low energy consumptions. The micro-LEDs with chip size less than 100 μm, still remain in the laboratory. The full-color solution, one of the key technologies along with its three main components, red, green, and blue chips, as well color conversion, and optical lens synthesis, are introduced in detail. Moreover, this review provides an account for contemporary technologies as well as a clear view of inorganic and miniaturized LED displays for the display community.

The metal halide perovskite nanocrystal (MHP-NC), an easy-to-fabricate and low cost fluorescent material, is recognized to be among the promising candidates of the color conversion material in the micro light-emitting diode (micro-LED) display, providing that the stability can be further enhanced. It is found that the water steam, oxygen, thermal radiation and light irradiation—four typical external factors in the ambient environment related to micro-LED display—can gradually alter and destroy the crystal lattice. Despite the similar phenomena of photoluminescence quenching, the respective encroaching processes related to these four factors are found to be different from one another. The encroaching mechanisms are collected and introduced in separate categories with respect to each external factor. Thereafter, a combined effect of these four factors in an environment mimicking real working conditions of micro-LED display are also introduced. Finally, recent progress on the full-color application of MHP-NC is also reviewed in brief.

The distributions of the electroluminescence of AlGaInP-based flip-chip red light-emitting diodes with a size of $100\,\,\mu \text{m}\,\,\times 200\,\,\mu \text{m}$ have been obtained via microscopic hyperspectral imaging by capturing spatially resolved light emission from the side of a transparent substrate. As the injected DC current exceeds the current corresponding to the maximum external quantum efficiency, the light emission from the current crowding region decreases due to the self-heating effect, whereas the emission of the region corresponding to the anode becomes dominant due to the low heat resistance.

Micro-LED displays have been recognized as the next-generation display technology. This review focuses on the recent progress in the pixel-driving technology of micro-LED displays.

The optical and chromatic characteristics of InGaN-based micro-light-emitting diodes (micro-LEDs) grown on silicon substrates with blue, green, and red emissions have been investigated. The red micro-LEDs exhibited a large full-width at half maximum and a strong blueshift upon increasing current density. The 20 μm blue, green, and red micro-LEDs achieve a maximum external quantum efficiency of 8.2% at 2.65 A/cm2, 5.1% at 5 A/cm2, and 0.62% at 0.1 A/cm2, respectively, which is superior to their 8 μm counterparts. The dependences of a color gamut on the temperature and current density of InGaN-based tri-color micro-LEDs can provide guidance for improving the performance of full-color micro-LED displays.