OLED Automotive Lighting Failure Detection via Leakage Resistance

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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, which is crucial for ensuring proper lighting functionality and safety.

Innovation Solution

The proposed solution involves an automobile lighting unit equipped with electronic means that determine the leakage resistance of the OLED light source's equivalent circuit and use this information to identify failure conditions, such as dead pixels or segments, by supplying a linearly increasing current ramp and measuring the voltage to determine the current/voltage characteristic curve and leakage resistance.

Engineering Contradictions & Design Principles

VSEngineering 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 functionality and design versatility are improved, but the ability to detect failure conditions of the OLED light sources deteriorates

Engineering Contradiction:
Improvelighting functionalityVSAvoidfailure detection capability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies preliminary action by implementing a diagnostic circuit that proactively measures leakage resistance of the OLED light source before complete failure occurs. The system continuously monitors the electrical characteristics of the OLED and detects deviations from normal operation, enabling early warning of potential failures. This allows the lighting unit to maintain reliability by detecting issues in advance, resolving the contradiction between using OLEDs for versatile lighting functions and maintaining failure detection capability.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If complex electronic diagnostic circuits are added to detect OLED failure conditions, then failure detection capability is improved, but device complexity increases

Engineering Contradiction:
Improvefailure detection capabilityVSAvoidelectronic circuit complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies self-service by designing a diagnostic circuit that utilizes the existing OLED light source itself as the test object. The same OLED that provides lighting functionality is also used to measure its own leakage resistance through the integrated diagnostic circuit. This eliminates the need for separate external testing equipment or complex additional sensor systems, thereby improving failure detection capability while minimizing the increase in device complexity.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The diagnostic circuit is designed to perform multiple functions: it measures leakage resistance to detect OLED failures, and can potentially be extended to monitor other electrical parameters of the OLED. This multi-functional approach allows a single electronic circuit to serve both the lighting control and diagnostic purposes, reducing overall system complexity while maintaining robust failure detection capability.

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

This approach allows for the reliable detection of OLED light source failures, enabling timely intervention and maintaining the lighting unit's performance and safety standards.

Implementation Method 1

determine a leakage resistance of an equivalent circuit of the OLED light source; determine a failure condition of the OLED light sources based on said leakage resistance

Methodology Applied
Scientific EffectElectrical Resistance: Electrical Resistance

Data Source

PatentEP3715884B1Automobile lighting unit with OLED light sources and related operating method
Publication Date: 2025.05.28 MARELLI AUTOMOTIVE LIGHTING ITAL SPA
  • EP3715884B1 patent drawingFigure 1
  • EP3715884B1 patent drawingFigure 2~3
  • EP3715884B1 patent drawingFigure 4~6

AI summary

Automotive lighting unit (1) comprising a lighting device equipped with one or more OLED light sources (6), and an electronic device (12) configured to determine a malfunctioning condition of an OLED light source (8). The electronic device (12) is suitable to determine a leakage resistance (Rp) of the OLED light source (8) and determines a malfunctioning condition of the OLED light source (6) based on the leakage resistance (Rp).