Solid-State Lighting Lighting applications that use light-emitting diodes (LEDs), organic light-emitting diodes (OLEDs), or light-emitting polymers are commonly referred to as solid-state lighting (SSL). Unlike incandescent or fluorescent lamps, which create light with filaments and gases encased in a glass bulb, solid-state lighting consists of semiconductors that convert electricity into light. LEDs have been around for nearly 50 years, but until a decade ago were used only in electronic devices as indicator lamps. Technological developments in the last two decades have allowed LEDs to be used in signal devices, like traffic lights and exit signs, and in some limited illumination applications, such as flashlights. However, cutting-edge research now shows a bright future for solid-state lighting as the next generation of light sources for general illumination, from homes to commercial applications. Solid-state lighting promises to change the way we light the world, yet much work and research are still needed. Solid-state lighting is increasingly used in a variety of lighting applications because it offers many benefits, including: Long life : LEDs and OLEDs can provide 50,000 hours or more of life, which can reduce maintenance costs. In comparison, an incandescent light bulb lasts approximately 1,000 hours. Energy savings : The best commercial white LED and OLED lighting systems provide three times the luminous efficacy (lumens per watt) of incandescent lighting. Coloured LEDs are especially advantageous for colored lighting applications because filters are not needed. Better quality light output : LEDs and OLED have minimum ultraviolet and infrared radiation. Intrinsically safe : LED OLED systems are low voltage and generally cool to the touch. Smaller, flexible light fixtures : The small size of LEDs and OLEDs makes them useful for lighting tight spaces and for creating unique applications. Durable : LEDs and OLEDs have no filament to break and can withstand vibrations.