Laminated Vehicle Glazing with Offset Bending for Low Optical Distortion
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Solution Overview
Problem
Existing methods for manufacturing laminated glazing, particularly for vehicle windshields, result in optical distortions due to imperfections in the glass surface caused by shaping members, which are amplified when the glazing is installed at angles, making it difficult to achieve high optical quality consistently.
Innovation Solution
A method involving offsetting the bending positions of the first and second sheets of glazing material by deliberate lateral and longitudinal displacements greater than the tolerance limits of the positioning means, allowing for improved alignment and reduced optical distortion when installed at angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If glass sheets are press-bent between shaping members, then the desired curvature is achieved, but surface imprints and optical distortion occur
Solution Approach 1:
The patent divides the glass sheet into multiple plies (typically three or more layers) with adhesive interlayers between them. This segmentation allows each ply to bear some of the bending stress, reducing the imprint depth on any single surface while achieving the desired overall curvature of the laminated glazing unit.
Solution Approach 2:
The patent employs asymmetric positioning of the glass plies within the laminated structure, where the inner ply and outer ply are positioned at different distances from the shaping members during bending. This asymmetric arrangement ensures that surface imprints occur on less critical surfaces or are distributed unevenly to minimize optical distortion in the driver's view area.
2Ease of manufacture
If glass sheets are positioned at the same location for bending, then manufacturing simplicity is maintained, but optical distortion is amplified when installed at angles
Solution Approach 1:
The patent deliberately positions the glass plies asymmetrically within the laminated structure, with the inner ply and outer ply offset from each other in the thickness direction. This asymmetric positioning causes surface imprints on different plies to be offset when viewed from an angle, reducing the amplification of optical distortion during installation.
Solution Approach 2:
The patent resolves the positioning conflict by moving the adjustment from the lateral/longitudinal dimensions to the thickness dimension. By offsetting plies in the thickness direction (z-axis) rather than adjusting their lateral positions, the patent maintains simple manufacturing while achieving reduced optical distortion through the asymmetric arrangement of multiple layers.
3Strength
If multiple glass plies are laminated with adhesive interlayers, then structural strength is improved, but lamination stresses may cause distortion
Solution Approach 1:
The patent divides the glazing into multiple plies separated by adhesive interlayers, which segments the structure to improve overall strength and safety. The segmentation also allows stress distribution across multiple interfaces, reducing the impact of lamination stresses on any single glass surface and minimizing distortion.
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 method produces laminated glazing with enhanced optical quality in transmission, reducing distortions even when installed at angles, by ensuring precise alignment and minimizing lamination stresses.
Implementation Method 1
joined by an interlayer structure comprising at least one sheet of adhesive interlayer material
Data Source
AI summary
Methods of making a laminated glazing having reduced optical distortion when installed in a vehicle are described. The laminated glazing has first and second sheets of glazing material each separately shaped between a pair of shaping members that are then laminated together. The position for bending the first sheet of glazing material may be deliberately offset from the position for bending the second sheet of glazing material. During the lamination step, the first sheet of glazing material may be displaced relative to the second sheet of glazing material by a lateral and/or longitudinal positional displacement. The first and/or second sheet of glazing material may have been cut such that after lamination at least a portion of the peripheral edges thereof are aligned. Apparatus for shaping a sheet of glazing material for carrying out the aforementioned methods is also described, as is a resulting laminated glazing.