Vehicle Lighting Dimming Threshold Control
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Solution Overview
Problem
Existing motor vehicle illumination devices experience color demixing and abrupt brightness changes during dimming processes due to limited resolution and predefined minimum brightness thresholds, leading to incorrect color settings and sudden light switching.
Innovation Solution
An electronic control unit dynamically determines a brightness threshold value based on the lowest non-zero color component value, adjusting it as needed during dimming processes to prevent color demixing and minimize sudden brightness changes by using this threshold value for calculating color values when brightness falls below it.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a predefined minimum brightness threshold value is used during dimming process, then color demixing is avoided to some extent, but the illumination device switches on and off abruptly during dimming
Solution Approach 1:
The brightness threshold value is determined dynamically based on the lowest color component value that is not equal to zero, rather than using a fixed universal threshold. This dynamic adaptation allows the threshold to adjust according to the current color mixing state, preventing both color demixing and abrupt switching during dimming transitions
Solution Approach 2:
The brightness threshold value is changed as a parameter that depends on the lowest non-zero color component value. By making the threshold a variable parameter rather than a constant, the system can maintain color accuracy while ensuring smooth transitions during dimming operations
2Device complexity
If integer color values with limited resolution are used, then calculation complexity is reduced, but color demixing occurs during dimming when brightness values decrease
Solution Approach 1:
The system performs a preliminary determination of the lowest non-zero color component value before calculating the brightness threshold. This preliminary action allows the system to pre-adjust the threshold to appropriate values that prevent color demixing, maintaining color accuracy while working within the constraints of integer color values
Solution Approach 2:
The system uses feedback from the color component values to dynamically adjust the brightness threshold. By continuously monitoring the lowest non-zero color component and adjusting the threshold accordingly, the system compensates for the limited resolution of integer color values and prevents color demixing during dimming
Data Source
AI summary
A lighting device in a motor vehicle includes a number of illumination devices, which each generate colored light via a plurality of color channels. The illumination devices can be controlled using an electronic control unit. An illumination state of a respective illumination device can be adjusted by color component values and a brightness end value for all color channels. The electronic control unit calculates a color value from the illumination state to be adjusted for each color channel based on the color component value of the respective color channel and the brightness value. The color value is supplied to the respective illumination device. The electronic control unit processes a brightness threshold value used during a dimming-down/dimming-up process for switching-off/on the respective illumination device. The brightness threshold value is determined by the electronic control unit and increases as the lowest color component value decreases.