WEBCAST: Light and Color - Methods of Achieving High CRI with LEDs

Oct. 3, 2011
This webcast on October 26 will discuss color-rendering determination methods, alternative color-quality scales, and evaluation of the advantages and disadvantages of CRI. The presentation will then look at different methods to create high-CRI white LEDs.
Title: Methods of Achieving High CRI with LEDs

Originally broadcast: Wednesday, October 26, 2011

Format: Live broadcast followed by audience Q&A.

Duration: Approx 1 hour in total

View the archived event

Presenter: Marc Dyble, Product Marketing Manager - Solid State Lighting, OSRAM Opto Semiconductors


In the past there were two different methods commonly used to create white light with LEDs. The first approach is through the combination of multiple colored semiconductor chips, usually red, green and blue (RGB), in multi-chip packages or LED clusters. The second approach is through the combination of a semiconductor chip (blue or UV) with converter materials (phosphors) through luminescence conversion within a single package. Phosphor conversion has been the most common method for general lighting applications. The color rendering index (CRI) of white-converted LEDs typically lies in the 70-85 range. The latest developments using enhanced phosphors increase the CRI value to 95, but the trade-off is lower efficacy.

There is now a new approach, recently developed, that combines the two existing methods to create a warm-white LED light source with a high color rendering index (CRI > 90) and high luminous efficacy. This new approach makes total luminous efficacies of over 110 lumens per watt (lm/W) possible, producing up to 50 percent more light than phosphor-converted warm-white LEDs (with a comparable CRI at the same power consumption). There are trade-offs with both methods. With the standard phosphor-conversion method, efficacy is reduced but implementation is easier. The new multiple LED-light-source approach attains much higher efficacy but entails greater complexity of implementation.

Key Learning Objectives:

• Gain an understanding of color-rendering determination methods and alternative color quality scales.

• Evaluation of the CRI advantages and disadvantages of current and new proposed white light LED solutions.

• Discussion of new techniques to achieve a higher color rendering index with LEDs.

• Exploration of High CRI achievement within color-tunable applications.


SPONSOR: OSRAM Opto Semiconductors


OSRAM Opto Semiconductors develops intelligent lighting solutions and is one of the world’s leading manufacturers of optoelectronic semiconductors. For more than 30 years the company has stood for innovative semiconductor technologies, setting standards in a wide range of applications. Its product portfolio includes components for the illumination, visualization and sensing sectors. High-power light emitting diodes (LEDs), semiconductor lasers, infrared diodes (IREDs) and detectors are among the most well-known products.




Marc T. Dyble

Marc Dyble is a Product Marketing Manager in the Solid State Lighting (SSL) group with OSRAM Opto Semiconductors, Inc., focused on the growth and development of architectural and outdoor lighting applications. Mr. Dyble is responsible for both product and marketing strategies for the North American SSL market. Prior to accepting his current position he was an Applications Engineer in the general illumination segment, supporting design development and customer applications.

Prior to joining OSRAM in 2006 Mr. Dyble held various positions in lighting engineering development with several architectural and entertainment lighting manufacturers, including Vari-Lite and Lighting Services Inc.

Mr. Dyble holds a Bachelor of Science Degree in Electrical Engineering from Southern Methodist University in Dallas, TX and a Masters of Science Degree in Lighting, specializing in Solid State Lighting, from the Lighting Research Center at Rensselaer Polytechnic Institute. Mr. Dyble also earned his lighting certification through the National Council on Qualifications for the Lighting Professions (NCQLP).