OLED Short Circuit Detection via Current Comparison
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Solution Overview
Problem
Conventional fuses fail to detect conditional short circuits in OLEDs, leading to local overheating and potential hazards such as fires, as they do not significantly alter current or resistance in such cases, and existing solutions do not effectively prevent injuries or fires.
Innovation Solution
An optoelectronic assembly with parallel-connected light emitting diode elements and an electronic circuit that compares currents flowing through each element to detect short circuits or conductivity changes, allowing for the identification of electrical properties like short circuits and initiating a switch-off when deviations exceed predefined thresholds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional fuses are used to detect short circuits, then the detection mechanism is simple, but conditional short circuits cannot be detected because voltage and current do not change significantly
Solution Approach 1:
The patent introduces an intermediary measurement mechanism (current sensor or voltage sensor) that indirectly detects short circuits by measuring changes in current or voltage across the OLED. This mediator allows detection of conditional short circuits without requiring direct intervention in the OLED structure, resolving the contradiction between simple detection and reliable detection.
Solution Approach 2:
The system implements feedback by continuously monitoring current or voltage parameters and comparing them against threshold values. When a deviation indicating a short circuit is detected, the system provides feedback to switch off the OLED, creating a closed-loop detection system that improves reliability while maintaining relatively simple device architecture.
2Productivity
If no detection system is implemented, then the device operates continuously, but local overheating and fire hazards cannot be prevented
Solution Approach 1:
The system performs preliminary detection by continuously monitoring current or voltage parameters before dangerous overheating occurs. By detecting conditional short circuits early through parameter deviations, the system can switch off the OLED preventively, avoiding the harmful effects of overheating and fire hazards while maintaining continuous operation capability.
Solution Approach 2:
The continuous monitoring and threshold-based detection creates a feedback mechanism that automatically responds to developing defects. This feedback loop enables the system to maintain productive continuous operation while simultaneously preventing harmful overheating by switching off the device when detection thresholds are exceeded.
3Reliability
If parallel connection of OLED elements is used, then the system can continue operating with one defective element, but current imbalance can mask short circuit detection
Solution Approach 1:
The patent applies local quality by measuring current or voltage specifically across individual OLED elements or segments rather than measuring total system current. This localized measurement approach allows detection of short circuits in specific elements even when other elements are operating in parallel, resolving the masking effect while preserving system continuity.
Solution Approach 2:
By introducing current sensors or voltage sensors as intermediaries that can selectively measure parameters of individual OLED elements, the system can detect local short circuits without being affected by the parallel operation of other elements. This intermediary measurement capability enables both system continuity and accurate defect detection.
Data Source
AI summary
In various embodiments, an optoelectronic assembly may include at least one organic light emitting diode including a first light emitting diode element and a second light emitting diode element, and an electronic circuit. The first light emitting diode element and the second light emitting diode element are electrically connected in parallel and are deposited monolithically on a common substrate, and the electronic circuit is designed to compare an electric current through the first light emitting diode element that flows during operation with an electric current through the second light emitting diode element that flows during operation and, depending on the comparison, to detect a short circuit of the first light emitting diode element or of the second light emitting diode element and to initiate an electrical switching off of one of the light emitting diode elements and/or of the assembly.