Lighting Ergonomics

Doing the lighting job right requires an understanding of the environment in which lighting will be used and the typical visual tasks that will be performed there.

The ultimate goal of most of the lighting systems under development here at LED Specialists (and, I would surmise, anyplace else) is to facilitate the performance of the human visual task in a given environment.

So what are the right light levels for a given application? Does one size fit all, or is it different for every person?

When Cadillac began introducing tilt wheel steering in the 1960s, I recall Mercedes-Benz scoffing at the very thought. Mercedes placed emphasis on its human factor research to determine the perfect location for the column, so why would anybody want to move it to a less optimal location?

Do today's MR-16s, PAR30s, A-19s, and T-8s (with their fixtures) deliver the best chromaticity, light distribution, and beam angle to light a room for human occupants to perform effectively? Is today's office lighting really optimal, or is there an as-yet-undefined set of lighting conditions that could render us 20% more efficient in our offices? How about on our roadways?

Understandably, so far much of the research with LED technology has been on metrics, standardization, and performance, and not so much on ergonomics. However, the advent of LED lighting represents a fundamental shift in our basic frame of reference and should usher in a new opportunity in lighting ergonomics.

Ergo, ergonomics. Merriam Webster's online dictionary defines ergonomics as "an applied science concerned with designing and arranging things people use so that the people and things interact most efficiently and safely -- called also biotechnology, human engineering, human factors."

Rethinking

It's time to rethink lighting within this new frame of reference. Closely associated with ergonomics -- and associated areas that also require more research -- are demographics (differences attributable to culture, age, interests, geographic location, social, status, language, gender, etc.), the influence of lighting on mood, and the influence on individual preferences. As an example, I might prefer a higher ambient light level than the average adult male, assuming that I am significantly older than the average.

Research progress

We are seeing some forward progress. Rensselaer Polytechnic Institute's Lighting Research Center is one of the institutions at the forefront of lighting research. In 2008, it published "Mesopic Street Lighting Demonstration and Evaluation Final Report for Groton Utilities." This paper proffered a new, unified photometry system to consider the combined functionality of photopic and scotopic vision more accurately under low light conditions. It showed that, in street light applications, visibility improved for sources with a higher concentration of shorter-wavelength visible light.

In 2005, LED Specialists supported another lighting research project at the LRC. The "LED Reading Light Study" sought to obtain user feedback on the qualities of the light produced by different sources for typical tasks, such as reading and using a computer. It concluded, among other things, that the optimum CCT for a reading light is around 4,000K.

There's so much more to do. What a time to be in lighting. I anticipate leaps forward in our understanding of human interaction with lighting.