Cube Corner Retroreflective Sheet Halation Reduction
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Solution Overview
Problem
Conventional retroreflective sheets used in vehicle license plates suffer from halation issues when exposed to infrared rays, leading to reduced visibility and whiteness, especially in automatic license plate recognition systems, where altering camera settings is costly or impractical, and incorporating infrared non-transmissive materials compromises whiteness.
Innovation Solution
A cube corner type retroreflective sheet is developed, comprising a base layer, print layer, cube corner elements, and an adhesive layer, where the adhesive layer includes whiteness enhancing and infrared non-transmissive materials, with the cube corner elements partially buried to control reflectivity and absorption, and an optional hologram layer for light diffraction, enhancing whiteness and reducing halation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If infrared non-transmissive materials are incorporated into the retroreflective sheet, then halation is reduced, but whiteness deteriorates
Solution Approach 1:
The retroreflective sheet is divided into multiple functional layers: a base layer containing infrared non-transmissive materials for halation reduction, a print layer with white pigments for whiteness enhancement, and a cube corner element layer for retroreflection. Each layer performs its specific function independently, allowing the infrared-blocking base layer and the white-printing layer to work together without interfering with each other's performance.
Solution Approach 2:
Different regions of the retroreflective sheet have different material compositions optimized for their specific functions. The base layer uses infrared-absorbing materials like carbon black or metal oxides localized at the bottom, while the print layer uses white pigments like titanium dioxide or zinc oxide positioned above it. This spatial differentiation of material properties allows simultaneous achievement of halation reduction and whiteness maintenance.
2Object-affected harmful factors
If the structure of the license plate is modified to include infrared non-transmissive materials, then infrared transmission is blocked, but manufacturing complexity increases
Solution Approach 1:
The infrared non-transmissive function is merged into the base layer of the retroreflective sheet itself, combining the infrared-blocking capability with the existing retroreflective structure. This integration eliminates the need for separate infrared-filtering components and simplifies the overall license plate construction while maintaining effective infrared halation reduction.
Solution Approach 2:
The base layer serves multiple functions simultaneously: it provides structural support for the retroreflective sheet, blocks infrared rays to prevent halation, and serves as a substrate for the print layer. This multi-functionality reduces the total number of components needed and simplifies the overall structure while achieving the desired infrared transmission control.
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 solution effectively improves the whiteness and reduces halation by selectively absorbing infrared rays, enhancing visibility of license plates without compromising their appearance, thereby addressing the limitations of existing retroreflective materials in license plate recognition systems.
Implementation Method 1
the adhesive layer includes at least one of a whiteness enhancing material and an infrared ray non-transmissive material
Implementation Method 2
the adhesive layer includes at least one of a whiteness enhancing material and an infrared ray non-transmissive material
Implementation Method 3
a retroreflective sheet has a characteristic of returning the light incident on the material towards the direction of the light source
Implementation Method 4
an optional hologram layer for light diffraction, enhancing whiteness and reducing halation
Data Source
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AI summary
The present disclosure relates to a cube corner type retroreflective sheet having cube corner elements, characterized in that the sheet comprises: a base layer; a print layer arranged at one side of the base layer; a plurality of cube corner elements that bond to the print layer, have a flat observation surface at one surface facing toward the print layer, and have a structure surface at the opposite surface; and an adhesive layer that bonds to the cube corner elements such that a portion of the structure surface of the cube corner elements is buried.