Product Selection Guide Page 1109 Product Selection Guide-11th Edition

1109 PRODUCT INFORMATION Color Quality LED TECHNICAL INFORMATION PSG11 TECHNICAL INFORMATION www.acuitybrands.com CIE 1931 Chromaticity Diagram For more information about color temperature specifically relative to LEDs, refer to this article on the Department of Energys website: Color Quality of White LEDs, located at: http://www1.eere.energy.gov/buildings/ssl/ factsheets.html. Special Distribution Charts showing varying mix of blue LED with yellow phosphor. COLOR QUALITY Color Temperature Color temperature is a metric that quantifies the color whiteness of a light source. For most white light applications, the range of color temperature extends from 2700K on the low end (warm, incandescent appearance) to higher than 5000K (cool, metal halide appearance) on the high end. In the world of LEDs today, the predominant method for generating white light is a combination of an LED emitting blue light with a coating of yellow phosphor. The phosphor acts to capture part of the blue emission and converts some of this to yellow light. As indicated by the arrows in the graph to the right, the combination results in white light. It is important to note that this conversion process incurs efficiency losses. The more blue light is converted to yellow, the higher the incurred losses. This explains why the most efficacious LEDs (highest lumens per watt) available today tend to be color temperatures of 4000K and higher. Over time, the gap in efficacy across the color temperature range will continue to close as LED manufacturers create more efficient phosphors. As seen in the illustration below, by applying different types of phosphors and/or varying the coating thickness, more of the blue light from the LED is converted to yellow. Color Quality With Respect to Digital LED Lighting

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