Lighting Research Center Lighting Research Center

SSL Projects

Research Categories

LED Lighting Applications and Demonstration
LED Package Research
Aviation Lighting
OLED Lighting
International Activities


LED Lighting Applications and Demonstration

Outdoor Applications

Tools to Evaluate Outdoor Lighting
A global trend to replace conventional outdoor lighting with LEDs led to the development of tools for evaluating and selecting both LED and conventional outdoor luminaires: a new metric rooted in the concept of application efficacy, a free online calculator based on this metric, and methods to assess discomfort glare and mesopic efficiency.

Parking Lot Lighting with Improved Uniformity
In this study, the Lighting Research Center sought to better understand the energy and user acceptance benefits of high illuminance uniformity on outdoor area or parking lot lighting.

ASSIST Application & Benefit Metric Guides
ASSIST has developed short design guides providing an overview of the main lighting characteristics that are important for different applications. Specifically, these guides suggest alternative ways to evaluate and compare LED solutions with traditional lighting technologies. The suggestions focus on how application metrics and benefit metrics can be used and contrasted to typical light source or luminaire metrics (e.g., luminous efficacy [lm/W]) when assessing the effectiveness of different lighting options at meeting the design objectives.

The Potential of Outdoor Lighting for Stimulating the Human Circadian System 
The Lighting Research Center and ASSIST sought to provide a quantitative analysis of the impact of light at night, particularly from streetlights of different spectral power distributions, on the human circadian system.

Effect of Colored Luminous Surrounds on LED Discomfort Glare pdf logo
The LRC investigated the connection between discomfort glare perception and the SPD of a luminous area surrounding a white LED array, taking into consideration the luminous surround spectrum, brightness perception, and the effect of a luminous surround on an LED array glare stimulus.

Indoor Applications

ASSIST Application & Benefit Metric Guides
ASSIST has developed short design guides providing an overview of the main lighting characteristics that are important for different applications. Specifically, these guides suggest alternative ways to evaluate and compare LED solutions with traditional lighting technologies. The suggestions focus on how application metrics and benefit metrics can be used and contrasted to typical light source or luminaire metrics (e.g., luminous efficacy [lm/W]) when assessing the effectiveness of different lighting options at meeting the design objectives.

ASSIST recommends… Assessing Direct Perception of Flickerpdf logo
ASSIST) has proposed a new method for measuring and quantifying direct perception of light source flicker.

ASSIST recommends… Light Source Flicker: Application Considerationspdf logo
ASSIST has published a guide describing experimental data that illustrate how detection and acceptability of stroboscopic effects change under different conditions that might be more applicable to certain lighting applications.

Reducing Flicker from AC LEDs  pdf logo
LRC researchers sought to create a new circuit design for AC LEDs with targeted benchmarks to ensure acceptable flicker levels and system performance.

LED Lighting for Multi-family Housing  
The LRC and ASSIST have published a guide for multi-family housing owners and facility managers on how to upgrade to LED lighting.

Electronic Walls and Ceilings Offer Adaptable Solid-State Lighting
Solid-state lighting offers new ways to think about how we light our spaces. The LRC has developed a flexible interior infrastructure that integrates solid-state lighting with other building materials and systems, allowing for rapid reconfigurations of built-in lighting.

Understanding White Light Source Color Rendering and Appearance
In 2002, the LRC and ASSIST began a long-term study of subjective preferences using psychophysical experiments to understand how observers perceive white light sources and what they prefer in terms of object color rendering and the white hue or tint of a light source.

Perceptions of White Light Sources of Different Color Temperatures  
The Lighting Research Center and ASSIST conducted a series of experiments to measure perceptions of white illumination from light sources of different CCTs.

Dimming Behaviors of LED Replacement Lamps  
LRC researchers investigated the dimming performance of commercially available LED and CFL replacement lamps and the performance variations among different dimmers. Human factors experiments were then designed to determine users' expectations for lamp dimming, which became the basis for ASSIST's technology-neutral lamp dimming recommendation.

LED Replacement for Linear Fluorescent Lamps pdf logo
The LRC investigated solutions for and built a prototype of an LED replacement for 4-foot linear T8 fluorescent lamps using remote phosphor technology.

LED Lighting for Supermarket Freezer Display Cases
In 2002, the LRC began investigating the possibility of using LEDs in supermarket refrigerator and freezer display cases, where fluorescent lamps are a common but not ideal technology for cold environments.


LED Package Research

Improving LED Light Output and Efficacy Through SPE™
The LRC’s Scattered Photon Extraction (SPE™) improves LED light output by up to 60% through the extraction of backscattered photons. The innovative package design combines remote-phosphor technology with optimally shaped secondary optics.

Estimating LED Life
Early 21st century claims purported LED lighting to last 100,000 hours. The LRC, however, showed that LED life could be far less, depending on the luminaire design and installation. Through its Alliance for Solid-State Illumination Systems and Technologies (ASSIST), the LRC developed a recommended test method for estimating LED life for general lighting.

Heat Transfer Analysis of a Remote Phosphor Layer pdf logo
Knowing the temperature and the temperature distribution across the phosphor layer is important for the design and manufacture of reliable LED packages. The objective of this study was to develop a mathematical model to predict the phosphor layer temperature profile.

Using Phosphor Luminescence to Reduce Ac LED Flicker pdf logo
LRC researchers investigated the luminescence of slow-decay phosphors and developed a mathematical model to predict the luminescent behavior to reduce the appearance of flicker from alternating current (ac) LEDs.

Degradation of LED Encapsulants pdf logo
This study evaluated the effects of short-wavelength radiation and thermal stress on the degradation of an epoxy LED encapsulant, with and without phosphor in the medium.

Managing Heat in the LED System’s Remote Phosphor Layer pdf logo
LRC researchers investigated methods to reduce the operating temperature of the remote phosphor layer and the resulting effects on LED performance.

Measuring LED Lens Surface Temperature with Thermocouples  pdf logo
The LRC conducted a study to understand the problems in using thermocouples to measure LED lens surface temperature and to find a solution to improve measurement accuracy.

Predicting LED System Failure through Real-time Changes pdf logo
This study sought to identify electrical and thermal parameters in a single-die InGaN LED package that could give real-time signals of impending failure while in use.

Minimizing Flicker from SSL Systems  
To assess the ability of individuals to perceive light source flicker directly and indirectly, and to understand the role of flicker characteristics on comfort, the LRC conducted laboratory studies under flickering patterns differing in frequency, modulation depth, duty cycle and waveform shape.

Estimating the Junction Temperature of AC LEDs
LRC researchers developed an alternative method of estimating AC LED junction temperature and thermal resistance.


Aviation Lighting

Bringing Advanced, Energy-Efficient LED Lighting to Aviation
Since 2005, the LRC has conducted lighting research as part of the Federal Aviation Administration’s Center of Excellence for Airport Technology. Research in the areas of solid-state lighting and vision science are providing new lighting solutions that benefit the aviation industry.

Long-term Evaluation of LED Airfield Luminaires pdf logo
LRC researchers conducted a long-term performance evaluation of LED airfield luminaires under operating temperatures that covered a range of realistic conditions, as a first step toward establishing a functional definition of useful life for these lighting systems.

Standalone PV-LED Lighting for Aviation
The LRC conducted a study to understand the factors that affect the performance of standalone PV-LED lighting systems, especially how the charge controller affects total system performance.

LED Blue Taxiway Luminaires
The LRC explored new luminaire designs and methods of transferring heat from the LED junction to the optics in order to minimize snow and ice buildup on blue airport taxiway luminaires.

Remote Airfield Lighting Systems
Many remote communities, such as those in Alaska, depend on air transport for business and emergency aid. Night landings at remote airfields are often dangerous. The LRC explored ways to help make night landings at remote airports safer and area communities more accessible.

Redefining White Light Chromaticity Boundaries for Aviation
The LRC conducted a human factors investigation of the boundaries in chromaticity space that people perceive as white and recommended new aviation white boundaries that were independent of the color limitations of incandescent sources.

Requirements for Runway Guard Lights pdf logo
The LRC conducted laboratory human factors experiments to determine the appropriate luminous intensity and other operating parameters of LEDs used in runway guard lights in order to provide acceptable visibility and safety.

LED Aviation Signal Brightness
LED signal lights have narrower spectral distributions than incandescent (filtered and unfiltered) signals, resulting in more saturated colors. Since color saturation increases the perception of brightness, the Federal Aviation Administration (FAA) asked the LRC to develop a set of “brightness correction factors” for white, green, and blue signal lights.

LED Aircraft Cabin Lighting for the 787 Dreamliner
The LRC partnered with Boeing to develop innovative and efficient lighting solutions for use aboard the 787 Dreamliner jet, a next-generation commercial airplane with energy-efficiency and passenger experience in mind.


OLED Lighting

OLED Lighting Education and Application Program
The LRC OLED-LEAP program's services are designed to help New York State manufacturers create successful, energy-efficient OLED lighting products for promising applications. OLED-LEAP will offer targeted R&D services (technical design guidance, prototype evaluation, testing and measurement, commercialization assistance, etc.) and professional education.

Exploring a Method for Measuring OLED Lumen Depreciation pdf logo
Currently there is no industry standard for measuring and reporting OLED lumen depreciation and lifetime data. Because the OLED is an area source, it is important to understand the overall light output depreciation and uniformity of the panel over time. LRC researchers explored a measurement method using an imaging photometer.

Measurement Method for Characterizing OLED Panels for Lighting Applications pdf logo
LRC researchers investigated an imaging-based photometric and colorimetric measurement method for long-term testing of OLED panels.



Professional LED Lighting Education
In 2001, the LRC began offering the first unbiased, research-based workshop for lighting designers, architects, and engineers on how to build successful LED lighting products and applications.

LED Lighting Summer Internship for Undergraduates
An eight-week paid summer internship program for undergraduates and recent graduates from engineering, physics, science, architecture, or industrial design who are interested in conducting research and learning more about the LED lighting field.

Outdoor Lighting Institute
A two-day course for engineers, lighting designers, municipal officials, utility personnel and others that provides the knowledge and tools needed to develop outdoor lighting installations that substantially reduce energy use and light pollution while improving safety and security

Photometry Institute
A two-day, hands-on course about the latest developments in photometric testing and evaluation, including new testing requirements for solid-state light sources and systems.


International Activities

International SSL Activities
In its global activities, the LRC provides information, technical training and guidance, and works to bring together public and private enterprises to focus on solutions to increase consumer accessibility to safe and energy-efficient lighting, particularly LED lighting systems that can work fluidly with off-grid or on-site renewable energy power generation systems.

Supporting South Asia Through LED Lighting Technology
In 2009, the LRC became the knowledge partner of the Regional Centre for Lighting (RCL) in South Asia, a Sri Lanka-based lighting research facility funded by the U.S. Agency for International Development and the Sri Lanka Sustainable Energy Authority. The RCL’s mission is to advance sustainable lighting and make it affordable to improve the well-being of the citizens and the eight countries within the region.

Testing LED Lighting Products for Lighting Africa Program
Lighting Africa, a joint program of the ICF and The World Bank, is aimed at helping 250 million people in Sub-Saharan Africa gain access to non-fossil fuel-based, low cost, high quality, safe, and reliable lighting products by the year 2030. The LRC is supporting the project through lab testing for quality assurance of off-grid lighting products developed by manufacturers for the Lighting Africa program.


 = ASSIST Project

Rensselaer Polytechnic Institute
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