Progressive-Thickness Windshield Film Stack for Low-Distortion Protection
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Solution Overview
Problem
Conventional laminated stacks of tearoff films for vehicle windshields suffer from reduced impact resistance and increased distortion due to the removal of each film, which compromises the protective benefit of the stack's total thickness.
Innovation Solution
A protective barrier comprising a stack of thermoplastic films with monotonically decreasing thicknesses, where each lens has a unique thickness, ensuring a greater total remaining thickness and balanced cushioning effect even after peeling off layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a laminated stack of tearoff films is used to protect the windshield, then impact cushioning is improved, but optical distortion increases
Solution Approach 1:
The patent applies local quality by varying the thickness of individual films within the stack. Thinner films are positioned where less cushioning is needed, while thicker films provide enhanced protection in areas requiring greater impact resistance. This non-uniform thickness distribution allows the stack to optimize both impact cushioning and optical clarity by matching film properties to local protective requirements.
2Ease of operation
If each film is removed as it becomes damaged, then visibility is maintained, but the total thickness and impact resistance are reduced
Solution Approach 1:
The patent applies preliminary action by pre-arranging films of different thicknesses in a specific sequence within the stack. This predetermined configuration ensures that as films are removed during use, the remaining films continue to provide optimized protection. The initial arrangement is designed so that thinner films are consumed first, preserving thicker films for later when greater impact resistance is needed.
3Duration of action of stationary object
If the windshield is protected from pitting and cracking, then the windshield lifespan is extended, but the cost and complexity of the protective system increases
Solution Approach 1:
The patent applies segmentation by dividing the protective function into multiple discrete film layers of varying thicknesses. Each film in the stack serves as an independent protective element that can be removed individually when damaged. This segmented approach allows the system to provide comprehensive protection across different impact scenarios while maintaining simplicity in the overall structure and ease of maintenance through individual film replacement.
Data Source
AI summary
A protective barrier is affixable to a curved substrate such as a vehicle windshield. The protective barrier may include a stack of three or more lenses. Each of the three or more lenses may include a thermoplastic film (preferably a polyethylene terephthalate (PET) film) and an adhesive layer on a first side of the thermoplastic film. The three or more lenses may have respective thicknesses that define a monotonically decreasing function in a stacking direction of the stack and that include at least three different thicknesses. The protective barrier may be placed on the curved substrate with the adhesive layer of an innermost lens of the stack in contact with the curved substrate, and heat and pressure may be applied to conform the stack to the shape of the curved substrate. Thereafter, an outermost lens of the stack may be peeled off to reveal the next lens of the stack.