Prismatic Light Pipe for Vehicle Exterior Lighting
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Solution Overview
Problem
Light pipes used in vehicle exterior lighting struggle to maintain adequate light emission when tilted or oriented around curves, failing to meet governmental photometric requirements while also adhering to styling demands, and using a single light source is advantageous for packaging, thermal performance, and cost but insufficient.
Innovation Solution
A light pipe design with prismatic cuts angled between 5 to 45 degrees from the normal axis, allowing for refracted light to be internally reflected, ensuring consistent light emission even when tilted or curved, and optionally incorporating a retroreflector to enhance light distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If light pipes are tilted or oriented around curves to meet styling requirements, then adaptability to vehicle design is improved, but light emission intensity deteriorates and fails to meet photometric requirements
Solution Approach 1:
The patent applies local quality by creating prismatic cuts with specific angle ranges (5-45 degrees from the normal axis) at specific locations on the light pipe. These localized structural modifications enable the light pipe to maintain consistent light emission intensity even when tilted or curved, resolving the contradiction between adaptability to styling and maintaining photometric performance.
Solution Approach 2:
The patent changes the geometric parameters of the prismatic cuts, specifically setting the angles between 5-45 degrees from the normal axis. This parameter optimization allows the light pipe to redirect light effectively when tilted or curved, maintaining illumination intensity across different orientations and thus resolving the contradiction between adaptability and light emission performance.
2Loss of energy
If prismatic cuts with large angles of inclusion are used to achieve total internal reflection, then light reflection efficiency is improved, but the light pipe appears dimmer when tilted away from perpendicular orientation
Solution Approach 1:
The patent optimizes the prismatic cut angles to be between 5-45 degrees from the normal axis, which is a significant departure from conventional large-angle prismatic cuts. This parameter change enables the light pipe to maintain effective light reflection and redirection even when tilted, thus improving both reflection efficiency and visibility when tilted simultaneously.
3Device complexity
If a single light source is used at one end of the light pipe, then packaging space and cost are reduced, but light distribution to distal ends with curves and angles becomes insufficient
Solution Approach 1:
The patent uses locally optimized prismatic cuts with specific angle ranges (5-45 degrees from the normal axis) positioned at critical locations along the light pipe. These localized optical structures ensure that even a single light source can effectively illuminate distal ends with curves and angles by redirecting light at optimal angles, thus maintaining reliability with reduced device complexity.
Solution Approach 2:
The patent introduces a new dimensional approach by optimizing the angular orientation of prismatic cuts in three-dimensional space. This allows a single light source to achieve effective light distribution throughout the light pipe, including curved and angled sections, by utilizing spatial light redirection rather than adding multiple light sources.
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 design ensures that light pipes can be oriented at angles without reducing light intensity, meeting photometric standards while allowing for single-source illumination, improving packaging, thermal performance, and reducing costs.
Implementation Method 1
The prismatic cuts are designed to refract light rays through at least one prismatic cut before the light rays are totally internally reflected
Implementation Method 2
the light beam is totally internally reflected and exits the light pipe through the surface opposite the prismatic cut
Data Source
AI summary
An illuminating device has a light pipe that is elongate in shape and has a light-emitting face running in the direction of a longitudinal axis. A light-reflecting face is disposed opposite the light-emitting face, and the light-reflecting face has a plurality of prismatic cuts. Each prismatic cut includes a front face oriented at an angle B from a normal axis, the normal axis being 90 degrees from the longitudinal axis of the light pipe. The angle B is in the range of about 5 degrees to about 45 degrees and is such that it allows light to refract through at least one prismatic cut and then be internally reflected.