TECHNICAL NOTEModel and Predict the Performanceof LEDs for Solid State LightingAccurately and QuicklyTracePro's Surface Source Property Generator helps users set up the Surface Source property-quickly and accurately.The macrotool reads the spectrum and angular radiation pattern from the manufacturer's datasheet.While useful for LEDs,this tool canalso be used to generate a Surface Source property for any type of light source.The setup files and instructions for installation ofthe Surface Source Property Generator may be downloaded from:http://www.lambdares.com/technical support/tracepro/utilities/LEDs for Solid State LightingThe use of LEDs for solid-state lighting to address applications in the automotive,architectural and generalilluminationmarkets is just emerging.LEDs promise greater energy efficiency and lower maintenance costs.However,there is a significantamount of design and cost optimization to be done while semiconductor companies continue to improve manufacturingprocesses.Furthermore,there is a lack of standards definitions and metrics-many definitions in the commercial lightingindustry are simply not applicable to LED technology.Predictive modeling of solid state lighting with TracePro opto-mechanical design software enables adherence to performance,consistency,cost,and aesthetic criteria without the cost and time associated with iterative hardware prototyping.Predictive Modeling of LED Sources with TraceProTraceProTracePro is a comprehensive,versatile software tool for modeling the propagation of light in opto-mechanical systems.Models are created by importing design files from a lens design program or a CAD program or by directly creating the solidgeometry in TracePro.Optical and mechanical properties are applied to materials and surfaces.Source rays propagatethrough the model with portions of the flux of each ray allocated for absorption,specular reflection and transmission,phosphorescence,and scattering.From the model,analyze:Light distributions in illumination and imaging systemsLumens exiting,absorbing,and incident at the component and system levelsCandela distributionsOptical efficiency,luminance and radiance metricsLuminance effects and lit appearanceFluorescence effects of phosphorsLambdaResearchPage 1www.lambdares.comTECHNICAL NOTEModel and Predict the Performance of LEDs for Solid State LightingModeling Optical Sources in TraceProThere are three methods of defining rays that launch into the model for ray trace-Grid,Surface and File sources.Most usefulfor modeling LEDs are Surface and File sources.A Surface Source emits rays from a user-defined source type in an angular distribution and spectrum from one or moresurfaces of a solid object.The example that follows makes use of the Surface Source method of defining rays that launch intothe model for ray trace.0650.2045420450.5714A File Source contains ray data and can be inserted into a TracePro model.Data consists of XYZ starting points for each ray,XYZ direction vectors for each ray,and a flux.A File Source allows the user to include actual measured source distribution datafrom companies offering LED characterization services such as Radiant Imaging,Inc (www.radiantimaging.com)or to includetheoretical and measured data from other software modeling applications such as Radiant Imaging's ProSourceTM program.2Page2TECHNICAL NOTEModel and Predict the Performance of LEDs for Solid State LightingModeling Opto-Mechanical Systems in TraceProTracePro can accommodate a true 3-D model ofan LED that provides not only an accurate optical model based on the sourcemodeling described above,but also provides an accurate opto-mechanical model.The opto-mechanical model is createdby importing the geometry from mechanical CAD files available from commercial manufacturers or by directly creating thegeometry in TracePro based on manufacturers'datasheets.The user can model the complete packaged LED.Create or import the geometry for the LED cup,LED lens,LED die,etc.andthen apply material and surface properties.Emitter bodySide-emitting lensCup-PnsIn the opto-mechanical model,define a surface of the die object as the Surface Source.In the Surface Source editor,define theangular distribution and spectrum.For higher level system modeling,the user can simply incorporate additional optics and mechanics to the packaged LEDsource models.Page 3