Light Guide Fixture System Alignment via Fixturing Cassette
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Solution Overview
Problem
Aligning light guides with LED sources in lighting devices is challenging due to insufficient structural rigidity and tolerance stack-up issues, leading to inefficient light reflection and potential misalignment during assembly and use, especially under vibrations.
Innovation Solution
A light guide fixture system that includes a fixturing cassette to securely align and position the light guide relative to the LED, utilizing locating features and mounting features to minimize tolerance stack-up and ensure accurate alignment, while allowing for translational movement to maintain alignment during assembly and operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the guide N is secured directly to the source S, then alignment between guide and source is improved, but the source lacks sufficient size, strength, or structural rigidity to secure the guide
Solution Approach 1:
A fixturing cassette is introduced as an intermediary component between the light guide and the LED source. The cassette includes a light guide-receiving region that secures the light guide and mounting features that attach to the heat sink, thereby indirectly securing the light guide to the source without requiring direct attachment to the fragile LED.
Solution Approach 2:
The mounting structure is divided into separate functional components: the fixturing cassette that holds the light guide, the heat sink that provides structural support, and mounting features that connect them. This segmentation allows each component to be optimized for its specific function while working together as a system.
2Strength
If the guide N is secured to a heat sink associated with the source S, then structural support is improved, but tolerance stack up between the guide and source increases
Solution Approach 1:
Mechanical alignment features such as locating pins, tapered surfaces, and self-centering mechanisms replace traditional multi-component mechanical mounting systems. This reduces the number of interfaces and accumulated tolerances between the light guide and LED source.
Solution Approach 2:
The fixturing cassette is pre-assembled with the light guide in a controlled environment, establishing precise alignment before installation. Locating features are pre-configured to ensure correct positioning, reducing alignment variability during final assembly.
3Illumination intensity
If the guide N is made with limited inherent structural strength for TIR function, then optical performance is improved, but difficulty to secure the guide increases
Solution Approach 1:
The light guide is designed with localized structural features: mounting surfaces and locating features are added only where needed for attachment, while the bulk of the light guide maintains its optimized optical geometry for total internal reflection. This allows the guide to be both optically efficient and mechanically secureable.
4Ease of operation
If traditional mounting methods are used, then assembly is simplified, but alignment accuracy under vibration and shock deteriorates
Solution Approach 1:
The fixturing cassette incorporates compliant or damped mounting features that can accommodate thermal expansion and mechanical stress from vibration and shock. The design allows for dynamic adjustment while maintaining alignment, rather than relying on rigid fixed positioning.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system achieves precise alignment of the light guide with the LED, reducing manufacturing costs, increasing optical performance, and ensuring the light guide remains aligned under normal use conditions, including vibrations, by using a fixturing cassette that securely fixes the light guide to the heat sink.
Implementation Method 1
The guide N is a total internal reflection (TIR) device
Data Source
AI summary
A light guide fixture system (10) includes a light guide (20) and a fixturing cassette (18). The guide (20) includes and a mounting surface (26) having a mounting feature (30) and a locating feature (28) for engaging a locating feature (72) of a light module (64) and align the guide (20) with respect to a light engine (12). The cassette (18) includes a light guide-receiving region (42) for receiving the mounting surface (26), a mounting feature (52), and a mounting region (44) for mounting the system (10) to the light module (64). The mounting features (30, 52) allow translational motion of the cassette (18) relative to the guide (20) when the guide (20) is received in the light guide-receiving region (42) while allowing the guide (20) to remain in the predetermined position. The cassette (18) secures the guide (20) to the light module (64).