WEBCAST: Light and Color - Methods of Achieving High CRI with 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
Presenter: Marc Dyble, Product Marketing Manager - Solid State Lighting, OSRAM Opto Semiconductors
Overview:
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.
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SPONSOR: OSRAM Opto Semiconductors
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PRESENTER
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Marc T. Dyble
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).
