Tilted Cube Corner Retroreflective Elements for Uniform Wide-Angle Performance
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Solution Overview
Problem
Conventional hexagonal cube corner retroreflective elements struggle to achieve uniform retroreflective efficiency and angle characteristics, particularly in traffic signs, due to symmetrical optical properties that vary with light incidence direction, limiting their effectiveness in all directions.
Innovation Solution
The use of cube corner retroreflective elements with optical axes tilted within a specific plane, including a common edge line and a perpendicular line from the apex to the common plane, allows for improved optical performance in all directions by tilting the axes to achieve uniform characteristics and rotation angles, enhancing retroreflective efficiency, entrance, observation, and rotation angle characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional hexagonal cube corner retroreflective elements with symmetrical optical properties are used, then the structure is simple and easy to manufacture, but the retroreflective efficiency and angle characteristics vary with light incidence direction, resulting in non-uniform optical performance
Solution Approach 1:
The patent applies asymmetry by tilting the optical axes of adjacent cube corner retroreflective elements in opposite directions. Instead of using symmetrical elements with vertical optical axes, the invention introduces asymmetric tilting where elements in alternating rows or positions have optical axes inclined at different angles, creating deliberate asymmetry to achieve uniform retroreflective characteristics across different viewing angles and incident light directions.
Solution Approach 2:
The patent segments the retroreflective sheeting into multiple rows or groups of cube corner elements, where each segment (row) contains elements with specific tilt orientations. By dividing the overall structure into segmented groups with different optical axis orientations, the invention achieves comprehensive angular coverage and uniform optical performance across the entire sheeting while maintaining manageable manufacturing complexity through modular arrangement.
2Illumination intensity
If the optical axes of cube corner retroreflective elements are tilted to improve wide-angle characteristics, then the observation angle characteristic improves, but the manufacturing precision and uniformity become more difficult to achieve
Solution Approach 1:
The patent applies parameter changes by systematically varying the tilt angles of optical axes across different element positions. Instead of maintaining a single fixed optical axis orientation, the invention changes the angular parameters of adjacent elements in a controlled pattern, where elements alternate between positive and negative tilt angles. This parameter variation optimizes retroreflective intensity across wide observation angles while the alternating pattern simplifies manufacturing by providing clear, repeatable positioning instructions.
Solution Approach 2:
The patent applies local quality by assigning different optical axis tilt orientations to specific local regions or positions within the retroreflective sheeting. Each cube corner element at a given position has a locally optimized tilt angle tailored to its specific location in the array, rather than using a uniform orientation throughout. This local optimization ensures that every region contributes to overall uniform wide-angle performance.
3Adaptability or versatility
If multiple types of cube corner elements with different optical axis orientations are arranged in a repeated pattern, then the rotation angle characteristic improves, but the device complexity and production difficulty increase
Solution Approach 1:
The patent applies periodic action by arranging cube corner elements with alternating optical axis tilt orientations in a regular, repeating pattern. Instead of using random or complex non-repeating arrangements, the invention employs a periodic structure where elements in alternating rows or positions follow a consistent tilt pattern (e.g., +θ, -θ, +θ, -θ). This periodic arrangement ensures rotation angle characteristic improvement while maintaining manufacturing simplicity through predictable, repeating unit cells that can be easily replicated during production.
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 approach enables a retroreflective article with excellent wide-angle characteristics, providing uniform optical and rotation angle performance in all directions, improving visibility and functionality in applications like traffic signs and construction signs.
Implementation Method 1
a first reflecting surface, a second reflecting surface, and a third reflecting surface which are mutually perpendicular to one another
Implementation Method 2
cube corner retroreflective elements having optical axes which are tilted with respect to each other within a plane
Data Source
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AI summary
A retroreflective article having excellent retroreflective efficiency, entrance angle characteristic, observation angle characteristic, and rotation angle characteristic is provided. In a retroreflective article including a number of cube corner retroreflective elements formed in a closely packed manner on a common plane (plane Sc), each of the cube corner retroreflective elements having three reflective lateral surfaces (surface a, surface b and surface c) that have three edge lines (HD, HE and HF) and one apex (H) in common and an optical axis that passes through the apex (H) and is at equal distance from the three reflective lateral surfaces (surface a, surface b and surface c), the retroreflective article includes at least two or more types of cube corner retroreflective elements having optical axes tilted with respect to each other within a plane (plane Sv) that is perpendicular to a reflective lateral surface (surface c) and includes a common edge line (HF) of the other reflective lateral surfaces (surface a and surface b) and a perpendicular line from the apex (H) to the common plane (plane Sc).