OLED Tail Light Failure Detection via PWM Off-Time Voltage Sensing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing automobile lighting units with OLED light sources lack an effective method to detect failure or breakage conditions of the OLED light sources.
Innovation Solution
An automobile lighting unit equipped with electronic means to control OLED light sources using a pilot signal with a trailing edge, determining an electrical quantity indicative of the OLED's electrical behavior during a measurement time interval, and detecting a failure condition based on this quantity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If OLED light sources are used in automobile lighting units to achieve homogeneous illuminating surfaces and dynamic graphic effects, then lighting versatility and visual quality are improved, but the ability to detect failure conditions of the OLED light sources deteriorates (no effective detection method exists)
Solution Approach 1:
The system performs preliminary diagnostic actions by analyzing the voltage decay curve of the OLED light source during its normal operation. The electronic means continuously monitors the electrical quantity (voltage) during a measurement time interval following the trailing edge of the pilot signal, and compares it against reference values to detect dead area states before they lead to complete failure or regulatory non-compliance.
Solution Approach 2:
The system implements feedback by using the measured electrical quantity (voltage decay characteristics) to determine the operational status of the OLED light source. The electronic means processes the voltage measurements during the measurement time interval and provides diagnostic feedback about the presence of dead areas, enabling continuous monitoring and early warning of degradation.
2Device complexity
If no failure detection method is implemented, then device complexity is reduced, but the ability to identify dead area states and photometric variations deteriorates
Solution Approach 1:
The OLED light source itself serves as the sensing element for failure detection. The natural voltage decay behavior of the OLED during the measurement time interval following the pilot signal's trailing edge contains diagnostic information about its health status. By monitoring this inherent electrical characteristic, the system achieves failure detection without requiring separate sensing components, thus maintaining simplicity while enabling precise dead area state identification.
3Measurement precision
If voltage measurement during OFF time interval is performed to detect dead area states, then detection accuracy is improved, but energy consumption increases due to continuous monitoring
Solution Approach 1:
The system performs voltage measurements periodically during the OFF time interval of the PWM pilot signal cycles rather than continuously. The measurement is synchronized with the natural switching rhythm of the OLED control, utilizing the existing PWM frequency (100-500 Hz) to perform diagnostic checks at appropriate intervals, thereby reducing energy consumption while maintaining detection accuracy.
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 solution enables timely detection of dead area states in OLED light emitting areas, allowing for prompt identification of significant photometric variations and potential regulatory non-compliance.
Implementation Method 1
OLED light sources make it easy to obtain homogeneous illuminating surfaces with which to dynamically produce new graphic effects
Implementation Method 2
determine an electrical quantity indicative of the electrical behaviour of said OLED light source in a measurement time interval following said trailing edge of said pilot signal
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
An automobile lighting unit (1) comprising a lighting device (4) provided with one or more OLED light sources (8), and an electronic device (12) configured in such a way as to control an OLED light source (8) by means of a pilot signal (P1) which has a trailing edge wherein the pilot signal (P1) varies between a high value (Vmax) and a low value (Vmin), to determine an electrical quantity (VS) indicative of the electrical behaviour of the OLED light source (8) in a measurement time interval (toff) following the trailing edge of said pilot signal (P1), and to determine a failure condition of the OLED light source (8) on the basis of an electrical quantity (VS).