LED technology: Evolution improves illumination

By Control Engineering Staff November 9, 2006
Optek’s Lednium Series Array is said to be among the brightest single source LED assemblies in the lighting industry.

As LED technology advances, its function has progressed from backlighting, indicators, and general illumination to use in warning signs, machine vision systems, and other industrial applications. Not only have uses increased, the LEDs have evolved from single chips to multi-chip arrays.

Industrial environments require devices that are reliable and long lasting. Traditionally, incandescent light bulbs have been used in the industrial arena, although their high heat, voltage, and power requirements have limited bulb reliability lifespan. LEDs have a lifespan more than 100 times that of incandescent bulbs, consume up to 90% less energy, and emit brighter light—characteristics that can present significant advantages.

For example, burned out warning lights on a machine can be dangerous for an operator who relies on those lights as indication of the status of the machine. In applications where lighting is required inside an enclosure, incandescent bulbs generate heat that can lead to their overheating and burning out. In addition to using less power and generating less heat, LEDs can be sealed to produce a safer device. The operator is able to see the indicators from a greater distance and safety is increased by LED bulb reliability.

Machine warning lights are among the industrial applications for LEDs. Many uses require a lighting assembly, rather than a single LED chip. LED assemblies are capable of providing virtually any color light in the visible spectrum in a 120° viewing angle.

LED arrays can achieve high brightness in a compact, energy-efficient package. LED assemblies can also provide parallel-serial connections that enable the operation of several mounted LEDs, allowing design engineers to vary light output and power consumption. Although LEDs generate less heat than incandescent bulbs, some applications still generate significant amounts. In those cases, LED assemblies may be constructed on specialized heat dissipating substrates. These thermally conductive substrates allow LED assemblies to run at full power, and reduce size and cost by minimizing the size of external heat sinks and mounting hardware.

In the near term, two types of LED assemblies—infrared (IR) and ultraviolet (UV)—likely will have a direct impact on industrial applications. Infrared LED assemblies are being constructed for use in heating and drying applications. For example, printing presses may use IR LED assemblies to dry ink. Although incandescent IR lights often waste energy due to their 360-degree bulb design, IR LED assemblies can provide concentrated energy in a more confined space. Such use results in more control, less energy consumption, and higher reliability.

UV LED assemblies may be specified in applications such as adhesive and finish curing. Because UV light emits tighter wavelengths, a highly controlled UV LED light source can be used for complex, fine-line lithography.

LED features of generating less heat, using less energy at lower voltage, and needing less power, coupled with longer lifespan, will continue to drive the LED market and the use of LED assemblies in a growing range of industrial environments.

—Richard Saffa, vice president, visible LED business unit,
Optek Technology, www.optekinc.com

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