Windscreen Curvature Measurement Using Multi-Line Triangulation

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Solution Overview

Problem

Existing methods for determining the curvature of glass panes, particularly windshields, fail to meet the increasing precision demands due to limitations in data accuracy and coverage.

Innovation Solution

A method involving a sensor device with at least three triangulation sensors, including an inner and outer triangulation sensors, that moves relative to the glass pane to record position data from multiple positions, allowing for precise curvature determination by analyzing scattered light patterns.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If three triangulation sensors are used to record curvature data along three lines, then the measurement coverage is improved, but the measurement precision is insufficient to meet increasing demands

Engineering Contradiction:
Improvemeasurement coverage areaVSAvoidcurvature measurement precision
Core Design Contradiction:
Area of stationary objectVSMeasurement precision

Solution Approach 1:

The patent divides the measurement task by using multiple triangulation sensors positioned at different locations (inner and outer sensors) to record position data from multiple positions in the transverse direction. This segmentation of the measurement area into multiple measurement lines allows comprehensive coverage while maintaining high precision through redundant measurements and cross-validation of curvature data from different sensor positions.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent extends the measurement from a single transverse position to multiple transverse positions by adding outer triangulation sensors. This dimensional expansion from one measurement line to multiple parallel measurement lines enables the system to capture curvature variations across the entire glass pane width, improving both coverage area and precision through multi-point measurement.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Measurement precision

If the number of triangulation sensors is increased to improve measurement precision, then the curvature determination accuracy is improved, but the device complexity increases

Engineering Contradiction:
Improvecurvature determination accuracyVSAvoidsensor device complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The sensor device is segmented into functional units with inner and outer triangulation sensors that can be independently positioned and calibrated. Each sensor unit operates semi-independently, recording position data from its specific transverse position, which simplifies the overall system architecture while achieving high precision through the combined data from multiple segmented measurement points.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The triangulation sensors serve multiple functions: they measure position data along their respective measurement lines, enable determination of curvature at multiple transverse positions, and provide redundant data for verification. This multi-functionality of the sensor system improves measurement precision without requiring separate specialized devices for each measurement task, thereby controlling device complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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

Enhances the accuracy and completeness of curvature measurement by doubling the number of data points, particularly in critical areas like those used for head-up displays, ensuring high optical quality and defect detection in windshield production.

Implementation Method 1

a light detection unit that detects the light scattered by the at least one glass pane

Methodology Applied
Scientific EffectLight scattering: Scattering

Data Source

PatentEP3844454B1Method for determining the curvature of a glass pane, more particularly a windscreen pane
Publication Date: 2026.01.28 NOKRA OPTISCHE PRUFTECHN & AUTOMATION
  • EP3844454B1 patent drawingFigure 1~2
  • EP3844454B1 patent drawingFigure 3~4
  • EP3844454B1 patent drawingFigure 5~6

AI summary

The subject matter of the invention is a method for determining the curvature of at least one glass pane (7, 8, 9), using at least three triangulation sensors (3, 17, 18), which in a transverse direction (2) have different positions, comprising an inner triangulation sensor (17) and at least two outer triangulation sensors arranged in the transverse direction (2) outside the inner triangulation sensor (17), wherein the outer triangulation sensors (18) record position data of at least two positions in the transverse direction (2). This can be done for example by moving the outer triangulation sensors (18) in the transverse direction (2) or by increasing the number of outer triangulation sensors (18), or also by arranging triangulation sensors (17, 18) that simultaneously record data of several positions in the transverse direction (2).