Cube Corner Retroreflector with Limited Visibility Range
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Solution Overview
Problem
Conventional retroreflective articles, such as pavement markers, are overly visible at long distances, leading to excessive road preview and driver distraction, as they are designed to maximize visibility at all observation angles without controlling the range of visibility.
Innovation Solution
The development of retroreflective articles with cube corner prism elements that selectively limit visibility by deviating dihedral angles, creating a pattern of retroreflection that is stronger at moderate distances and weaker at both closer and farther distances, thereby controlling the range of visibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional retroreflective articles are designed to maximize visibility at all observation angles, then visibility at long distances is improved, but driver distraction and excessive road preview occur
Solution Approach 1:
The retroreflector is designed with non-uniform light distribution characteristics, creating different visibility intensities at different observation angles. Specifically, the retroreflected light is concentrated in a controlled angular pattern that provides high intensity at moderate distances (where drivers need to see the marker) while deliberately reducing intensity at very small observation angles (long distances). This local differentiation of light intensity resolves the contradiction by making the retroreflector selectively visible - bright enough for safety at appropriate distances, but dim enough to avoid distraction at excessive distances.
2Illumination intensity
If retroreflective articles are made highly visible at all distances, then safety visibility is improved, but excessive visibility at long distances causes road preview
Solution Approach 1:
The invention changes the angular distribution parameter of retroreflected light rather than simply increasing or decreasing overall intensity. By controlling the dihedral angles of the cube corner elements and the geometry of the retroreflector, the light is redirected into a specific angular pattern that limits visibility to a predetermined range. This parameter change enables the retroreflector to provide sufficient brightness for safety at moderate distances while automatically reducing visibility beyond the desired range, thus controlling road preview without compromising safety visibility.
3Adaptability or versatility
If cube corner elements reflect light in all directions, then visibility from multiple angles is improved, but light intensity is diluted and range control is lost
Solution Approach 1:
The retroreflector employs asymmetric light distribution by designing cube corner elements with specific dihedral angle deviations from the ideal 90 degrees. This asymmetry causes the retroreflected light to follow a non-uniform angular pattern rather than distributing equally in all directions. The result is that light intensity is concentrated in specific angular zones where driver visibility is needed, while other angular regions receive reduced intensity. This asymmetric distribution maintains adaptability to multiple viewing angles while preserving light intensity concentration, resolving the contradiction between versatility and intensity.
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 solution ensures that retroreflective articles are visible to drivers at necessary distances for safety while minimizing excessive visibility at longer distances, reducing driver distraction and road preview.
Implementation Method 1
cube corner versions of these articles have a frontal lens of clear, colored or uncolored resin, such as methyl methacrylate, with a smooth front surface and a plurality of retroreflective cube corner elements on the rear surface
Data Source
AI summary
Retroreflective articles having cube corner elements are disclosed, with the dihedral angle errors of the cube corner elements selected to limit the visibility range of the retroreflective article. Also disclosed are methods for making the cube corner elements and the retroreflective articles.