Efficient Stray Light Root Cause Analysis: RayPath Analyzer Utilization Guide

Stray light analysis can become increasingly complex as optical systems contain more components and surfaces. Light may undergo multiple transmissions, reflections, and refractions before reaching the receiving surface, making it difficult to identify the root cause of unwanted light from illuminance or luminance distributions alone.

This application note explains how RayPath Analyzer can help optical and illumination designers investigate stray light by organizing ray-tracing path information, identifying relevant light paths, and visualizing those paths on a 3D model. The approach helps designers understand not only where unwanted light reaches the receiving surface, but also which surfaces and interactions contributed to the resulting stray light.

The document presents a practical workflow for stray light root cause analysis. Designers can begin by identifying a specific problem area on the receiving surface and selecting the corresponding rays for investigation. Ray paths can then be narrowed down using conditions such as surfaces the rays passed through, path power, and the number of surface hits. Multiple conditions can be combined to focus the analysis on relevant ray paths while comparing how the resulting distribution changes.

RayPath Analyzer also enables designers to compare extracted ray paths with illuminance or luminance distributions and display the corresponding paths on a 3D optical model. This makes it easier to understand the sequence of ray interactions, identify reflection locations, and associate specific optical paths with unwanted light phenomena.

The application note also discusses total internal reflection (TIR), which can intentionally guide light but may also create unexpected stray light paths depending on the optical design and incident conditions. By identifying paths that include total internal reflection, designers can examine where TIR occurs and evaluate potential design changes involving shape, surface treatment, light shielding, or component arrangement.

By combining ray path filtering, distribution analysis, 3D visualization, and TIR analysis, RayPath Analyzer helps optical designers investigate stray light root causes and identify potential design changes. The workflow can also support design reviews and technical communication by connecting observed optical phenomena with their causal ray paths and potential countermeasures.