Polymer Interlayer Gradient Band for Uniform Windshield Tint Fade
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Solution Overview
Problem
Current techniques for producing interlayers with gradient bands for laminated glass, such as those used in automobile windshields, face challenges in achieving uniformity and high visual appeal due to difficulties in controlling the visible light transmittance spectrum, often resulting in unwanted optical illusions like the Mach band and variations in color density.
Innovation Solution
The development of a process involving a sheet extrusion die with a probe configuration that ensures parallel streamlines of the polymer flow, allowing for the encapsulation of a colored gradient band within a clear portion, where specific parameters like distance D and ratio D/d are maintained to optimize the fade-off and prevent color diffusion into adjacent layers, thereby enhancing the gradient beauty.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If current techniques for producing interlayers with gradient bands are used, then production can be achieved, but uniformity and visual appeal deteriorate due to unwanted optical illusions like Mach band and color density variations
Solution Approach 1:
The patent applies local quality by varying the concentration of colorant or plasticizer specifically in the gradient band region compared to the clear portion. This localized compositional difference creates the desired gradient effect while controlling the transition zone to minimize Mach band formation. The probe introduces material at a specific location to create this localized variation in properties.
Solution Approach 2:
The patent utilizes parameter changes by controlling the concentration ratio of colorant to plasticizer (or other additives) to achieve different optical densities in different regions. By adjusting these compositional parameters during the extrusion process, particularly maintaining specific D and d values, the gradient band achieves uniform appearance without unwanted optical illusions.
2Illumination intensity
If a colored gradient band is produced in an interlayer, then aesthetic appeal and sunlight reduction are improved, but control of visible light transmittance spectrum deteriorates leading to color density variations
Solution Approach 1:
The patent controls the concentration ratio of colorant to plasticizer to precisely adjust the visible light transmittance spectrum. By maintaining specific D and d values (where D is the distance from the edge of the gradient band to the point where the color density is 40% of the maximum, and d is the distance from that point to the point where the color density is 10% of the maximum), the gradient band achieves both aesthetic appeal and uniform color density without unwanted variations.
Solution Approach 2:
The patent employs feedback by measuring and controlling the D and d parameters during production to ensure consistent gradient band quality. This feedback mechanism allows for real-time adjustment of the extrusion process to maintain uniform color density and achieve the desired sunlight transmission control.
3Shape
If probe extrusion technique is used to create gradient band, then encapsulation within clear portion is achieved, but control of fade-off characteristics deteriorates
Solution Approach 1:
The patent controls the fade-off characteristics by precisely managing the D and d parameters during the probe extrusion process. By adjusting the concentration ratio of colorant to plasticizer and controlling the extrusion conditions, the gradient band achieves smooth and uniform fade-off from the colored region to the clear region, preventing abrupt transitions that would create visual defects.
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 results in interlayers with improved gradient beauty and reduced Mach band severity, achieving a uniform and aesthetically pleasing transmittance spectrum, as demonstrated by controlled D and d values within specified ranges, ensuring high visual quality and consistency.
Implementation Method 1
ensures parallel streamlines of the polymer flow
Data Source
AI summary
Polymer interlayers having improved gradient bands and laminates comprising these interlayers are disclosed. The polymer interlayers and laminates comprising polymer interlayers have a gradient band that has a high level of gradient beauty from the perspective of visible light transmittance spectra.