Complete characterization of the near-field output of light sources for optical device and illumination design

           

Radiant Source Models (RSMs) provide the most accurate method of modeling the near-field output of real light sources for use in optical and illumination design software. They are used for light source analysis to investigate fine scale performance for light source design and development and for optical and illumination design to create accurate performance simulations. RSMs can be used by optical and illumination design engineers to simulate virtually any type of light source, including LEDs, fluorescent lights, arc, tungsten halogen and HID lamps.

RSM data files are available from Radiant Zemax as downloads from our extensive library of light source measurements or via our RSM measurement service for new light source models. RSMs can be used to generate ray sets that are compatible with leading optical and illumination design software programs such as ASAP, FRED, LightTools, SimuLux, SPEOS, TracePro, and Zemax.

Complete information for light source performance evaluation

It is often difficult or impossible for an engineer to obtain all of the data necessary to accurately model a light source through traditional means, such as combining various shapes in optical design software and applying estimated luminance values to each component. An RSM solves this by providing the full luminance field (both angular and spatial distributions) of a representative light source. These measurements are obtained using Radiant Zemax' Source Imaging Goniometer (SIG) and PM-NFMS measurement systems.

The resulting RSMs are comprised of luminance images, color images (if colorimetric measurements are made), and spectral data (if spectral data is collected together with the images) of the light source from thousands of viewing angles.

This source data provides the light source designer or developer with tremendous flexibility in investigating the performance of the light source:

• Anomalous or discontinuous performance can be directly investigated by viewing the relevant measurement images using Radiant Zemax' ProSource software.
• Photopic, colorimetric, and even spectral ray sets can be generated for use in major optical design software packages.

Efficient, flexible ray set generation using importance sampling improves optical design

Using ProSource, RSMs can be used to generate ray sets for export to optical design software with full control over the number of rays generated (from a few million rays for rough design to tens of millions of rays for final, detailed design), the angular range of the rays, the total luminous flux of the ray set and ray origin.

ProSource uses "importance sampling" to generate efficient ray sets, with results that are superior to traditional Monte Carlo methods for generating ray sets. By taking the full near-field data into account, importance sampling associates rays with meaningful source features, and so obtains the same accuracy in representing the source with only a fifth of the number of rays required with Monte Carlo methods. Importance sampling can only be done if the full near-field data is available, as with RSMs.

This reduction in the number of rays that must be analyzed allows faster processing in optical design software-saving time and allowing more options to be evaluated without sacrificing accuracy.

Try it yourself!

Demonstration versions of both Radiant Source Models and ProSource software are available as downloads. The Radiant Source Model demos contain a sample data set that enables visual inspection of the model but not ray set generation.

The demo version of ProSource software is a fully functional version of the program; however, it only allows access to the Radiant Source Model demo files. A security key and license code must be ordered to use it with standard Radiant Source Models.