Automotive Windshield Bending to Reduce Vertical Double Imaging
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Solution Overview
Problem
Automotive windshields with high curvatures and large sizes, produced using gravity bending, exhibit excessive vertical double imaging due to slight thinning of glass panes, leading to increased optical defects and reduced clarity, especially when highly inclined.
Innovation Solution
Bending the glass panes using a solid mold with mechanical or pneumatic force to reduce thickness variations to less than 10 μm over 500 mm, thereby minimizing double imaging to acceptable levels, while allowing for preliminary gravity bending to enhance curvature complexity without degrading optical quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If gravity bending is used to produce large, highly curved windshields, then manufacturing complexity is reduced and ease of manufacture is improved, but vertical double imaging increases excessively
Solution Approach 1:
The patent changes the bending method from gravity bending to solid mold bending, fundamentally altering the process parameters. This involves using mechanical or pneumatic force applied through a solid mold to control the bending process, thereby reducing thickness variations and minimizing vertical double imaging while maintaining manufacturing feasibility
Solution Approach 2:
The patent replaces the gravity-based bending system with a solid mold bending system that uses controlled mechanical or pneumatic force. This substitution allows precise control over the bending process, ensuring uniform thickness distribution and reducing optical defects like vertical double imaging
2Adaptability or versatility
If glass panes are bent to high curvatures and large sizes, then adaptability to modern automotive designs is improved, but thickness variations increase leading to excessive double imaging
Solution Approach 1:
The patent introduces a solid mold as an intermediary between the glass pane and the bending force. This solid mold acts as a mediator that distributes the mechanical or pneumatic force uniformly across the glass surface, enabling high curvature and large size while maintaining precise thickness control and minimizing variations
Solution Approach 2:
The patent employs preliminary gravity bending followed by solid mold bending. The preliminary action of gravity bending prepares the glass pane by introducing initial curvature, which then allows the solid mold to refine the shape with precise thickness control, achieving both high adaptability and manufacturing precision
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 significantly reduces vertical double imaging to imperceptible levels at a 20° viewing angle, improving the optical transmission quality and aesthetic appeal of automotive glazing by maintaining the product of bending depths and curvature radii within specified limits.
Implementation Method 1
Bending the glass panes using a solid mold with mechanical or pneumatic force
Implementation Method 2
Bending the glass panes using a solid mold with mechanical or pneumatic force
Implementation Method 3
produced using gravity bending
Data Source
AI summary
The invention relates to a curved glass pane, made of float glass, the area of a main face of which is greater than 1.5 m2 and the product of its two depths of bending is greater than 3000 mm2, and such that its point located on the normal to its surface passing through its center of gravity has a radius of curvature of less than 3 m in any direction, the variation in its thickness in the longitudinal float direction being less than 10 μm over 500 mm. This pane may be assembled into laminated glazing of the automobile windshield type. Such a windshield has a very small amount of double imaging even when it is fitted into the vehicle so as to be close to the horizontal.