User-Based Definition for Lamp Dimming

Article ID: 604586

Released: 20-Jun-2013 10:10 AM EDT

Source Newsroom: Rensselaer Polytechnic Institute (RPI)

Newswise — The Alliance for Solid-State Illumination Systems and Technologies (ASSIST), a program of the Lighting Research Center (LRC) at Rensselaer Polytechnic Institute, recently released a new publication that addresses the issue of how lamps should dim in terms of their “look and feel” during the dimming process. The publication, ASSIST recommends… Dimming: A Technology-neutral Definition, provides a recommended definition for lamp dimming in residential and hospitality applications, based on research of existing industry standards, laboratory evaluations of lamp and dimming control performance, and psychophysical experiments conducted to determine common user expectations and preferences.

As new replacement lamp technologies become viable for many applications, manufacturers must design for the many facets of general illumination that the consumer expects, like dimming with standard wall dimmers. LEDs are intrinsically dimmable light sources and are commonly marketed as such; however, that does not mean that all integrated LED lighting products, particularly replacement lamps for incandescent lighting, are dimmable, or that residential dimmable LED products provide the same end-user experience when coupled with the existing installed base of dimmers. Compact fluorescent lamps have similar issues as well. Thus, dimming has been often discussed as one feature that needs to work well for energy-efficient lighting to achieve widespread adoption in general lighting applications. Even though dimming is a feature commonly expected in many lighting applications, there is no standard definition for dimming in the industry. Over a two-year period, researchers from the Lighting Research Center at Rensselaer Polytechnic Institute, on behalf of ASSIST, conducted technology performance and compatibility evaluations, human factors experiments, and reviews of existing industry standards to better understand the different aspects of lamp dimming. The results of this research led to the published ASSIST recommends, which outlines recommended minimum and maximum light levels, thresholds for dead travel, flicker, and audible noise, and definitions for dimming profile and system efficacy measurement. Nadarajah Narendran, Ph.D., LRC director of research and organizer of the ASSIST program, notes that the goal of ASSIST’s dimming recommendation is to have manufacturers understand and meet users’ expectations for dimmed lighting, helping LED technology to gain widespread use in lighting applications. “The LRC and ASSIST’s industry members are interested in understanding the technical problems impeding market acceptance of LED lighting, and dimming is one focus area. By understanding the compatibility issues and what users want when they dim their lights, we can improve not only the dimming experience but also the likelihood that homeowners will permanently switch to energy-efficient LED lighting,” said Dr. Narendran. The ASSIST recommends publication is available on the ASSIST website at An overview of the dimming research conducted by the Lighting Research Center is available at About ASSISTThe Alliance for Solid-State Illumination Systems and Technologies (ASSIST) was established in 2002 by the Lighting Research Center as a collaboration between researchers, manufacturers, and government organizations. ASSIST’s mission is to enable the broad adoption of solid-state lighting by providing factual information based on applied research and by visualizing future applications. The Lighting Research Center conducts research, demonstration, and educational activities on behalf of ASSIST. ASSIST is sponsored by 3M; Acuity Brands Lighting; Amerlux; Bridgelux; Cirrus Logic; Cooper Industries; Cree; Dow Corning; Federal Aviation Administration; GE Lighting Solutions; ITRI, Industrial Technology Research Institute; Intematix Corp.; LG Electronics; LG Innotek; Lite-On; New York State Energy Research and Development Authority (NYSERDA); OSRAM SYLVANIA/OSRAM Opto Semiconductors; Philips Lighting; POSCO LED; Samsung; Seoul Semiconductor; Soraa; Toshiba; United States Environmental Protection; WattStopper.

About ASSIST recommendsASSIST recommends is a publication program of the Alliance for Solid-State Illumination Systems and Technologies (ASSIST) that offers formal recommendations to the LED and lighting communities about issues important for the reliable performance of LED lighting and its comparison to other light source technologies. The first ASSIST recommends publication in 2005 provided a definition and method for estimating the useful life of LED lighting, which later became the basis for the Illuminating Engineering Society’s LED lumen maintenance standard, known as LM-80. The publications available include recommended definitions, testing and measurement methods, calculation methods, and best practices. All ASSIST recommends publications can be downloaded for free at



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