HUD Laminated Glazing Interlayer Profile for Ghost Image and Bubble Reduction
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Solution Overview
Problem
Existing laminated glazings for head-up displays (HUDs) suffer from ghost images due to the reflection of projector images on both surfaces of the windshield, and the production of wedge-shaped interlayers with precise wedge angles is complex and expensive, leading to insufficient de-airing and bubble formation during the lamination process.
Innovation Solution
A laminated glazing with a thermoplastic intermediate layer having a minimum thickness of 900µm and a wedge angle increasing monotonically between the upper and lower edges, ensuring a concave shape that minimizes bubble formation and enhances de-airing performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a non-linear wedge-shaped interlayer is used to reduce ghost images, then the HUD image quality is improved, but bubble formation occurs during lamination due to insufficient de-airing
Solution Approach 1:
The invention changes the geometric parameters of the interlayer by introducing a controlled convex curvature in the HUD region. This modifies the thickness distribution profile from a simple linear wedge to a more complex shape with a curvature radius of 500-2000mm, which alters the air evacuation dynamics during lamination while maintaining the wedge angle necessary for ghost image reduction
Solution Approach 2:
The invention applies a convex curvature to the interlayer in the HUD region, creating a rounded profile rather than a sharp angular wedge. This curvature with radius 500-2000mm allows air bubbles to escape more easily during the lamination process while still maintaining the optical properties needed to reduce ghost images
2Manufacturing precision
If a wedge-shaped interlayer is produced by extrusion with a wedge-shaped die, then the desired wedge angle is achieved, but the production process becomes very expensive and complex
Solution Approach 1:
The invention prepares the interlayer by first creating a flat or slightly curved base layer, then selectively applying additional thickness or curvature to the HUD region. This preliminary preparation allows the wedge shape to be achieved through simpler subsequent processes rather than requiring complex wedge-shaped extrusion dies from the start
Solution Approach 2:
The invention applies the wedge shape and curvature only locally in the HUD region rather than across the entire interlayer. This localized approach allows standard extrusion or lamination equipment to be used for the majority of the interlayer, with the complex geometry applied only where needed, reducing overall manufacturing complexity
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 effectively reduces the formation of bubbles inside the laminated glass, increases the lifespan of the glazing, and minimizes ghost images in HUD projections, while simplifying and economizing the production process.
Implementation Method 1
images are projected onto the windshield, reflected there, and perceived by the driver as a virtual image
Implementation Method 2
two glass panes that are laminated to one another via a thermoplastic intermediate interlayer
Data Source
Figure 1
Figure 2~3
AI summary
A laminated glazing (10) for a head-up display (HUD) (5) is described. The laminated glazing (10) has an outer (1) and an inner (2) glass panes, which are bonded to one another via a thermoplastic intermediate layer (3). The intermediate (layer 3) in the vertical course (C) between a lower edge L and the upper U edge of the laminated glazing (10) is variable at least in sections between two virtual points P1 and P2 taken along the vertical course (C). According to the present invention, the calculated surface area (S) surrounded a straight line connecting a first value V1 defined by a position(d(1))and a thickness (Tk(1)) of the virtual point P1 and the last value V2 defined by a position (d(2)) and a thickness (Tk(2)) of the virtual point P2 is above 10.000mmxµm.