Mechanically flexible, optically transparent displays are attractive in the market for portable devices. OLED (organic light emitting diode) meets these characteristics, which makes it in a technology of constant research and development that seeks to strengthen its performance and expand its range of applications. This article presents an overview of architecture and operating principles of OLED, the materials used in its manufacture, the types of organic lightemitting diodes developed, the multilayer and arrays organic diodes, its efficiency and potential applications.