Automotive Rear Window Glazing Draw Line Orientation
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Solution Overview
Problem
Automotive rear window glazings made from laminated glass, installed at high angles to the vertical, exhibit significant transmitted optical distortion due to unevenness in the plastics interlayer material, particularly the draw lines, which worsens the view for drivers when looking through the rear view mirror at an oblique angle.
Innovation Solution
The rear window glazing is designed with the draw lines in the plastics interlayer material extending from the top edge to the bottom edge, aligning with the orientation of the glass draw lines, to reduce transmitted optical distortion, and may include thinner, chemically toughened glass for enhanced safety and reduced weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the draw lines in the plastics interlayer material extend from side to side (conventional orientation), then the manufacturing process is simplified and material usage is optimized, but transmitted optical distortion increases significantly when the glazing is installed at high angles to the vertical
Solution Approach 1:
The patent changes the orientation parameter of the draw lines in the plastics interlayer material from the conventional side-to-side direction to a top-to-bottom direction. This parameter change specifically addresses the optical distortion issue when the glazing is installed at high angles to the vertical, while the manufacturing process remains substantially unchanged.
2Reliability
If laminated glass is used in automotive rear windows installed at high angles to the vertical, then safety and security are improved, but transmitted optical distortion worsens due to the interaction between glass draw lines and interlayer draw lines
Solution Approach 1:
The patent changes the orientation parameter of the interlayer draw lines to be substantially parallel to the glass draw lines (both extending top-to-bottom when installed). This alignment of parameters reduces the complex interaction between mismatched draw lines, thereby reducing transmitted optical distortion while maintaining the safety and security benefits of laminated glass.
Solution Approach 2:
The patent introduces asymmetry in the orientation of draw lines relative to the installation angle. By orienting the interlayer draw lines to match the glass draw line orientation rather than using the conventional symmetric side-to-side arrangement, the system achieves better optical performance at high installation angles.
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 configuration significantly reduces the noticeable distortion, improving the driver's view through the rear window, even at high installation angles, by minimizing the effect of refractive power variations across the glazing surfaces.
Implementation Method 1
a ply of plastics interlayer material extending between the plies of glass and bonding the plies of glass together
Implementation Method 2
Transmitted optical distortion in a sheet of glass arises when the major surfaces of the glass are not completely parallel to each other, so that local areas of the glass act as lenses, albeit with a very low refractive power
Data Source
AI summary
An automotive rear window glazing for installation in a car, comprises at least two plies of glazing material and at least one ply of plastics interlayer material extending between the plies of glazing material, the ply of plastics interlayer material being substantially co-extensive with the plies of glazing material and bonding the plies of glazing material to each other, wherein the ply of plastics interlayer material contains draw lines extending in substantially one direction, the automotive rear window glazing has a top edge and a bottom edge, and wherein the automotive rear window glazing is installed with the draw lines in the plastics interlayer material extending from the top to the bottom edges.