Reflection Display Masking Detection Using Ambient Brightness Sensing
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Solution Overview
Problem
Reflection display systems in vehicles, such as PHUDs, face challenges in detecting foreign objects on the dashboard that mask display images, leading to obscured safety-relevant information due to their depressed arrangement, which prevents direct visibility and causes glare, and existing solutions like cameras or light barriers are inadequate.
Innovation Solution
A method involving a sequence of measurement display images with varying patterns and lighting intensities is used, combined with an ambient brightness sensor to detect foreign objects by evaluating brightness profiles against a reference, signaling their presence to ensure uninterrupted display visibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the display unit is arranged in a depression on the upper side of the dashboard to prevent direct view and avoid glare, then the user is protected from dazzle, but foreign objects resting on the display unit become not readily visible and can mask parts of the display
Solution Approach 1:
The patent introduces an intermediary detection system consisting of ambient brightness sensors and a control unit that indirectly detects foreign objects by monitoring brightness profile deviations. Instead of directly observing the display surface, the system uses brightness measurements as an intermediary indicator to infer the presence of masking objects.
Solution Approach 2:
The patent replaces direct visual inspection (mechanical/optical observation) with an automated electronic detection system using brightness sensors and signal processing. The mechanical approach of visually checking the display surface is substituted by an electronic system that measures brightness profiles and compares them against reference profiles to detect foreign objects.
2Difficulty of detecting and measuring
If additional devices such as cameras or light barriers are used to detect foreign objects, then foreign object detection capability is improved, but device complexity increases
Solution Approach 1:
The patent makes the ambient brightness sensor multi-functional by using it both for its primary function (measuring ambient light levels for display adaptation) and for the secondary function of detecting foreign objects on the display surface. This eliminates the need for separate dedicated detection devices and reduces overall system complexity.
Solution Approach 2:
The patent merges the foreign object detection function with the existing ambient brightness measurement functionality. By combining these functions into a single sensor system and processing pipeline, the patent avoids adding separate cameras or light barriers, thereby maintaining system simplicity while achieving detection capability.
3Strength
If a cover glass is used in the reflection display device, then the display structure is protected, but new reflections of ambient light onto the windshield are caused which significantly impair the perceptibility of the reflection image when there is high ambient brightness
Solution Approach 1:
The patent extracts or removes the cover glass element from the reflection display system to eliminate the source of parasitic reflections. By taking out this component, the system avoids the harmful effect of multiple reflections that impair image perceptibility under high ambient brightness conditions.
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 approach allows for the automated detection and signaling of foreign objects on the display surface, ensuring continuous visibility of safety-relevant information and adapting to ambient brightness conditions, thereby preventing information masking.
Implementation Method 1
displaying a display image for a vehicle occupant of a motor vehicle by reflection of the display image on a reflection surface, in particular on a front windshield
Data Source
AI summary
A method for operating a reflection display system for displaying a display image for a vehicle occupant of a motor vehicle by reflection of the display image on a reflection surface, in particular on a front windscreen, includes outputting a sequence of measurement display images with different patterns with different lighting intensities in some regions; detecting a brightness signal by an ambient brightness sensor while each measurement display image of the sequence is being displayed in order to obtain a brightness profile of the brightness signals; evaluating the profile of the brightness signals with respect to a predefined reference brightness profile which specifies brightness signals when the display surface is uncovered, for the sequence of measurement display images with constant ambient brightness; and signaling the presence of a foreign object on the display surface depending on the result of the evaluation.