Since incandescent lighting was first invented by Joseph Wilson Swan and Thomas Edison in the 19th century, lighting technology has taken giant leaps forward. Valerie Poyurs, director of marketing at the Radiant Group (Radiant), suggests that miniature light-emitting diodes (LEDs) are set to become the standard source of illumination for the 21st century.
An LED is essentially a diode that emits light. It is based on chip technology. The diagram illustrates the principles of LED construction. Current is applied to the cathode lead which then excites the atoms to a higher energy level. They release this energy through the bonding wire as the atoms shed electrons to the material used in the LED chip.
During this energy transfer light is created. The lens focuses the light created from the chip into the beam shape and defined direction, while the thermal heat-sink draws heat away from the chip.
LEDs produce monochromatic radiation – their colour tone is defined by the dominant wavelength according to the type and composition of the semiconductor crystal used in the LED chip. They are available in red, orange, yellow, green and blue. White light is created when the three colours – red, blue, green (RGB) – are combined.
Poyurs highlights some of the many advantages of using LEDs.
LEDs are more energy-efficient than incandescent and most halogen light sources. They use less energy to produce the same – or even higher – levels of light.
LEDs are also longer lasting. Their lifespan depends on the operational and environmental temperature. At room temperature, LEDs have a lifespan of up to 50 000 working hours over an 11-year period. In addition, they contain solid-state technology. In contrast to filament lamps, there is nothing to break, so replacement and maintenance costs are lower.
In LEDs the decline in light intensity (degradation) is also significantly lower than in other light sources.
Unlike most fluorescent sources, LEDs contain no mercury and therefore present no hazards of leaking or contamination, either in use or in disposal.
There is no ultraviolet (UV) or infrared (IR) radiation in the LED light beam. LEDs produce a cool beam of light and are safe to touch.
LEDs turn on instantly, within micro-seconds. They produce vivid, saturated colours and they do not require filters to create colour, which waste light. They allow for dynamic colour control in changing applications and offer an endless choice of colours.
Unlike conventional light sources which produce omni-directional light (light in all directions), LEDs emit directional light. They are fully dimmable with no colour variation. The lamps can be dimmed over 1 000 times without sacrificing any characteristic of the light.
Because LEDs are much smaller, they also offer design flexibility. Their compact nature opens up new optical design possibilities.
Radiant’s rapidly growing range of LEDs reflects its focus on these light sources as an established component of lighting concepts and one which is likely to take over from general conventional lighting in the near future.