Stepped Light Guide Thickness Reduction
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Solution Overview
Problem
Existing light guides in vehicle lighting systems face challenges in maintaining a uniform thickness for manufacturing and packaging while using total internal reflection (TIR) principles, which is essential for efficient light distribution, and metalized reflectors can cause electromagnetic interference.
Innovation Solution
The design of a light guide with stepped light-reflecting and light-emitting faces, where the light-emitting surface is stepped back to match the back surface, and the straight sections between 45-degree steps are angled to reduce the overall thickness, allowing for TIR without the need for metalized reflectors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the light guide uses traditional 45-degree stepped design with TIR principles, then light reflection efficiency is improved, but the thickness becomes too large for practical manufacturing and packaging
Solution Approach 1:
The patent changes the angle parameter from traditional 45-degree steps to alternative angles (such as 30-degree or other customized angles). This parameter modification allows the light guide to achieve effective light reflection while reducing the overall thickness to practical levels for manufacturing and packaging applications.
Solution Approach 2:
The patent transitions from a two-dimensional stepped profile to a three-dimensional design incorporating curved surfaces and varied cross-sections. This dimensional change enables more efficient light path management within a reduced thickness envelope, allowing TIR principles to work effectively in a compact form factor.
2Ease of manufacture
If the light guide thickness is reduced for manufacturing and packaging, then manufacturing practicality is improved, but the ability to maintain effective TIR reflection is compromised
Solution Approach 1:
By modifying the angular parameters and incorporating curved surface elements, the patent maintains sufficient optical path length within the reduced thickness to ensure effective TIR reflection, while achieving a thickness suitable for manufacturing and packaging requirements.
Solution Approach 2:
The patent incorporates curved surfaces instead of purely flat stepped surfaces. These curved elements help maintain the optical path length necessary for TIR reflection while fitting within a reduced thickness profile, thus preserving reflection effectiveness in a manufacturable form.
3Shape
If the light guide maintains uniform thickness for styling requirements, then aesthetic appearance is improved, but the light reflection performance using TIR principles deteriorates
Solution Approach 1:
The patent uses curved surfaces and three-dimensional profiling to achieve a more uniform external thickness appearance while internally maintaining the necessary optical path geometry for effective TIR reflection. The curved design allows aesthetic uniformity without sacrificing optical performance.
Solution Approach 2:
The patent applies different surface characteristics to different regions: the external surface is designed for uniform aesthetic appearance, while internal surfaces maintain the specific angular and curved geometries needed for effective TIR reflection. This local differentiation resolves the conflict between appearance and performance.
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
This design achieves a reduced thickness for the light guide while maintaining effective light reflection through TIR, avoiding electromagnetic interference and meeting customer styling requirements for a uniform lit appearance.
Implementation Method 1
The plurality of light-reflecting faces is configured to reflect light rays by the principle of total internal reflection
Data Source
AI summary
A light guide includes a body having an elongate shape and a plurality of light-reflecting faces and light-emitting faces extending along the body. The light-reflecting faces extend in a stepped fashion along the body in the direction of a longitudinal axis of the light guide and are configured to reflect light rays by the principle of total internal reflection. Each light-emitting face is disposed along the body opposite a corresponding light-reflecting face. Each light-emitting face is configured to emit light reflected by the corresponding light-reflecting face. The light-emitting faces are also disposed on the body in a stepped fashion. Steps of the light-emitting faces correspond to steps of the light-reflecting faces. In another aspect, the light-reflecting faces are separated by stepped-down faces. The stepped-down faces are oriented at a stepped-down angle in the range of about 1 and 10 degrees with respect to the longitudinal axis of the light guide.