Laminated Windshield Wedge Profile for HUD Double Image Reduction

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Solution Overview

Problem

Conventional laminated glass designs struggle to achieve high-quality transparent and reflected images due to inconsistent wedge angles, leading to double image issues.

Innovation Solution

A laminated glass design with variable wedge angles, specifically varying between 0.1 mrad and 1.5 mrad, is implemented, with glass plates and an intermediate film arranged to minimize rapid angle changes and ensure optimal image quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a constant wedge angle is used in laminated glass, then manufacturing is simpler, but double image quality deteriorates

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoiddouble image quality
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent applies local quality by varying the wedge angle of the intermediate film according to different regions of the laminated glass. The wedge angle is designed to be different in the HUD display region compared to the transparent region, allowing each region to have optimized optical properties for its specific function, thereby eliminating double images while maintaining manufacturing feasibility.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent implements parameter changes by modifying the wedge angle parameter of the intermediate film. Instead of using a constant wedge angle, the patent specifies different wedge angle ranges for different regions (e.g., 0.1-1.5 mrad in HUD region, different values in transparent region), which resolves the double image problem by adjusting the optical path differences in each region.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If the wedge angle varies rapidly across the glass, then double image reduction is improved in some regions, but image quality deteriorates due to distortion

Engineering Contradiction:
Improvedouble image reductionVSAvoidimage quality
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The patent applies local quality by defining specific wedge angle ranges for different functional regions. The HUD display region uses one wedge angle range optimized for reflected image quality, while the transparent region uses another range optimized for transparent view quality, preventing rapid angle changes that would cause distortion.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent implements a dynamic wedge angle distribution that transitions smoothly between regions. The wedge angle is designed to vary gradually rather than abruptly, with specific constraints on the rate of change, allowing the optical properties to adapt to different viewing requirements while maintaining overall image quality.

Inventive Principle:
Principle #15Dynamics

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 design achieves high-quality transparent and reflected images by controlling wedge angle variations, reducing double images and maintaining glass quality.

Implementation Method 1

a laminated glass obtained by holding with two glass plates an intermediate film having a cross section having a shape of a wedge, a wedge angle of the intermediate film being changed depending on a location in the front windshield

Methodology Applied
Scientific EffectRefraction: Refraction

Data Source

PatentEP3269547B1Laminated glass
Publication Date: 2025.09.03 AGC INC
  • EP3269547B1 patent drawingFigure 1A~1B
  • EP3269547B1 patent drawingFigure 2A~2B
  • EP3269547B1 patent drawingFigure 3~4

AI summary

A laminated glass includes first and second glass plates to be arranged on a vehicle inner side and outer side, respectively; and an intermediate film positioned between the first and second glass plates and bonded to the glass plates. The laminated glass includes a first region, a transition region, and a. second region, from a lower side of the laminated glass. Each of the first and second regions includes a region having a wedge-shaped cross section, in which an upper edge side thickness is greater than a lower edge side thickness, or having a thickness that is constant. The transition region connects the first and second regions, and includes a region having a wedge-shaped cross section, in which an upper edge side thickness is greater than a lower edge side thickness. At least one of the first and second regions includes a region used for a head up display.