LightTools 6.2 models LED phosphors, does backward ray tracing

LightTools 6.2, the latest version of the illumination-design and analysis software produced by Optical Research Associates (ORA; Pasadena, CA), has some new features that, in this age of energy-efficient lighting design, will surely be well-used.

First, it now has the ability to model white-light LEDs in a more true-to-life way, giving the designer the ability to specify materials with multiple phosphor particles, along with their size and density distributions.

Second, it has been given a backward ray-tracing capability, which can greatly reduce the time needed to design and analyze systems such as sources, luminaires, and projectors. The approach saves time by tracing many fewer rays than a forward ray trace would require to reach the same level of accuracy. The capability allows the designer to analyze illuminance, intensity, and color at a particular location, or in a particular direction, rather than taking unnecessary time to analyze the entire pattern.

Third, as designers create ever-more-complex light-carrying structures to not only extract every last bit of light from LEDs and other high-efficiency sources, but to deliver the light in the most-useful illumination pattern possible, the new LightTools SolidWorks Link Module allows users to build 3-D models in SolidWorks and import them into LightTools, where they can assign optical properties, optimize the design, and update the SolidWorks model. The capability provides full interoperability, so that changes made in one program are updated in the other.

A fourth new feature is especially useful to luminaire designers by allowing intensity data to be collected as a set of variable-width slices over a full sphere. With this approach, all collection bins in a given slice have the same size, preventing statistical noise issues near the polar regions of the intensity distribution. Data collection in this format enables far-field intensity data exchange with other lighting-design software through the widely supported IES (Illuminating Engineering Society) and LDT (Eulumdat) data formats.

The LightTools' Backlight Pattern Optimization utility also improves the design of keypads, dashboards and instrument panels. Designers can use a bitmap image of the desired illumination pattern as a merit-function target during optimization, which allows portions of a light guide to be selectively illuminated.