Windscreen Display Cover Detection for Obstructed HUD Images

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Solution Overview

Problem

Reflective display systems in motor vehicles, such as PHUDs, face issues with foreign objects obstructing the light path of the display image, making safety-relevant symbols invisible and difficult to detect, especially when the display unit is recessed on the instrument panel.

Innovation Solution

A detection sensor system, including light barrier, reflective light measuring, cover glass, touch, image acquisition, and ultrasonic sensors, is used to detect foreign objects on the display surface by interrupting light beams or altering reflection characteristics, enabling the control unit to signal obstruction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If the display unit is recessed on the instrument panel to prevent direct viewing and avoid glare, then the glare problem is reduced, but foreign objects on the display surface become invisible and can obstruct the light path

Engineering Contradiction:
ImproveglareVSAvoidforeign object detection
Core Design Contradiction:
Object-affected harmful factorsVSDifficulty of detecting and measuring

Solution Approach 1:

A detection sensor system acts as an intermediary between the display unit and the environment, detecting foreign objects through light interaction without requiring direct visual observation by the user. The sensor system includes light sources and detectors that interact with foreign objects on the display surface, enabling indirect detection while maintaining the recessed display design.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces visual inspection (mechanical/optical direct observation) with an automated sensor-based detection system. Instead of relying on users to visually detect foreign objects, the system uses light sources, photodetectors, and evaluation units to automatically sense and evaluate foreign object presence through changes in light reflection, absorption, or scattering properties.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Ease of operation

If the display unit is recessed on the instrument panel, then direct viewing is prevented, but foreign objects resting on the display surface are not readily visible and can obstruct the light path

Engineering Contradiction:
Improvedisplay operationVSAvoiddisplay information visibility
Core Design Contradiction:
Ease of operationVSLoss of information

Solution Approach 1:

The detection sensor system provides continuous feedback about the display surface condition to the evaluation unit. When foreign objects are detected through light interaction changes, the system generates signals that can trigger warnings or alerts, providing feedback about potential information obstruction without requiring users to visually inspect the recessed display area.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The detection sensor system performs preliminary detection of foreign objects before they can obstruct the display light path. By continuously monitoring the display surface with light sources and detectors, the system identifies foreign objects in advance, allowing for preventive measures to be taken before critical display information becomes obscured.

Inventive Principle:
Principle #10Preliminary action

3Strength

If a cover glass is used in the display system, then the display surface is protected, but new reflections of ambient light are created that significantly impair perceptibility in high ambient brightness

Engineering Contradiction:
Improvedisplay surface protectionVSAvoidreflected light intensity
Core Design Contradiction:
StrengthVSIllumination intensity

Solution Approach 1:

The detection sensor system applies local quality detection by using targeted light sources and detectors positioned specifically to interact with the display surface. Instead of relying on ambient light that creates harmful reflections, the system uses controlled local illumination and detection zones that are insensitive to ambient brightness conditions, enabling foreign object detection regardless of overall illumination intensity.

Inventive Principle:
Principle #3Local quality

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

Automated detection of foreign objects on the display surface allows for timely warning or countermeasures, ensuring visibility of critical display information by identifying and signaling obstructions.

Implementation Method 1

a light barrier sensor configured to detect the presence of the foreign object by detecting an interruption of one or more light beams guided along the surface of the display area

Methodology Applied
Scientific EffectLight absorption: Absorption (EM radiation)

Implementation Method 2

a reflective light measuring sensor configured to detect the presence of the foreign object, in particular by measuring a change in the reflection characteristics of light directed onto the display surface

Methodology Applied
Scientific EffectLight reflection: Reflection

Data Source

PatentEP4337488B1Method and device for operating a windscreen display system with a cover detection system, and windscreen display system
Publication Date: 2026.02.04 BAYERISCHE MOTOREN WERKE AG
  • EP4337488B1 patent drawingFigure 1~2b
  • EP4337488B1 patent drawingFigure 3~5
  • EP4337488B1 patent drawingFigure 6~7

AI summary

The invention relates to a reflection display system for displaying a display image for a vehicle occupant of a motor vehicle by reflecting the display image on a windshield, comprising: - a display unit which is designed to display the display image via a display surface of the display unit, wherein the display unit is arranged on an upper face of a dashboard, in particular in a recess, such that a reflection of the display image via the windshield can be perceived in the eye region of a vehicle occupant, - a detection sensor system which is designed to detect a foreign object present on the display surface; and - a control unit which is designed to signal a disruption of the display of the display image if the foreign object is detected on the display surface.