Over the years, these tiny diodes have improved in color range, lumen output, color stability, lifespan, and other performance factors, allowing LEDs to encroach on, and dominate, many niche lighting markets from indicator lights and traffic signals to exit signs and decorative architectural lighting.
Because a single LED is comparatively small, it can be assembled into an array of dozens or even hundreds of dies on a panel or a strip. Therefore, an LED “fixture” can be any size or shape. As a result, solid-state lighting has the potential to reduce complexity in the selection, design, and installation of lighting fixtures. Traditional and newly emerging lighting fixture manufacturers are actively studying applications in which LEDs are suitable and then working backward to develop fixtures that can be easily mounted, effectively maintained, and economically controlled.
For suppliers striving to introduce LED lighting into the general illumination market, the biggest challenge is to provide high lumen output from dies that produce white light. For electrical engineers and installing electrical contractors, the challenge is to learn more about this technology so that they can specify and install high-quality, specification-grade products to the satisfaction of demanding clients.
At present, virtually no standards for measuring, reporting, testing, or applying LEDs exist, but overly optimistic or irrelevant claims about these emerging LED products could severely curtail market acceptance. Fortunately, many organizations, believing that LEDs offer tremendous market potential, are cooperating in standards development.
For example, the Illuminating Engineering Society of North America (IESNA) and the Next Generation Lighting Industry Alliance (NGLIA) are working with the U.S. Department of Energy (DOE) Building Technologies Program to achieve a number of goals, including developing procedures for photometric measurements of LEDs, laser diodes, organic LEDs, and any other semiconductor light sources of the future.
In 2007, Underwriters Laboratories Inc. (UL) will publish UL 8750, “Outline of Investigation (OOI) for LED Light Sources for Use in Lighting Products.” When released, this OOI will be applied in any investigation of the LED light sources used in UL-listed lighting products. According to UL, in terms of fire risk, the temperature rise exhibited by LED systems might bring them close to the limit of 90°C — the maximum temperature permitted on surfaces under the building codes within the U.S.
Because LED products can take on a variety of sizes and shapes, they offer tremendous opportunities for innovative lighting solutions in both interior and exterior lighting design. Rather than distributing light from a single, bright source within a fixture, LEDs can place light across a surface or deliver it in multiple planes. They can be integrated into architectural materials, such as concrete, and they can edge light glass or plastic panels.
Here is an example of LED lighting innovation in Tom Hegen’s Greenhouse Series of agriculture greenhouse LED lighting research that explores the evolution of what agricultural lighting and cityscapes will look like as technology advances to solve growing uses around food production in an ever-expanding world.