LED Chain Outage Protection via Breakdown Layer

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Solution Overview

Problem

Series-connected LED or OLED lighting elements fail entirely when a single element fails, as the circuit is interrupted, and existing solutions do not effectively restore functionality to the entire chain without additional components or costs.

Innovation Solution

Integration of a thin breakdown layer, such as an oxide layer, that breaks down to bridge the failed element, reconnecting the circuit and ensuring functionality of remaining elements without additional components or costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single light element fails in a series-connected chain, then the circuit is interrupted and the entire chain fails, but adding switching elements or shunts increases device complexity and manufacturing costs

Engineering Contradiction:
Improvechain functionalityVSAvoidadditional components
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the insulating layer and conductive bridge into a single integrated structure that is already present in the OLED manufacturing process. The insulating layer is formed during standard fabrication, and the conductive bridge is created by applying conductive paste through screen printing or similar techniques, merging protection and restoration functions into the base structure without adding separate components.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The system uses the failure condition itself (high voltage across the failed element) to trigger the breakdown of the insulating layer, which automatically activates the conductive bridge to restore the circuit. This self-activating mechanism eliminates the need for external control circuits, sensors, or additional switching components.

Inventive Principle:
Principle #25Self-service

2Reliability

If a breakdown layer is made thin to ensure reliable breakdown at high voltage, then unintended bridging may occur at normal operating voltage, but making it thick prevents breakdown when needed

Engineering Contradiction:
Improvebreakdown reliabilityVSAvoidunintended bridging
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent carefully controls the thickness parameter of the insulating layer to fall within a specific range (10-100 nm) that creates the desired voltage-dependent behavior. This parameter optimization ensures the layer remains insulating at normal operating voltages (2-3V) while breaking down reliably at failure voltages (multiple times the operating voltage), resolving the contradiction between premature breakdown and failure to breakdown.

Inventive Principle:
Principle #35Parameter changes

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 breakdown layer effectively bypasses failed OLEDs, maintaining the functionality of the remaining elements while preventing unintended bridging of functional OLEDs, ensuring high reliability and security against voltage peaks.

Implementation Method 1

The breakdown layer is applied to current-carrying structures and breaks down if a lighting element fails due to the high voltage that then occurs, so the conductive layer above it and the current-carrying structure (e.g. the cathode material underneath) are conductively connected

Methodology Applied
Scientific EffectBreakdown layer breakdown: Avalanche Breakdown

Data Source

PatentEP1927973B1Structure assembly and method for outage protection of an LED or OLED chain
Publication Date: 2017.05.03 OSRAM OLED
  • EP1927973B1 patent drawingFigure 1

AI summary

The arrangement has multiple LED or organic LED light units (11) switched in series. A weak spot in the form of a perforation layer (5) i.e. oxide layer, is integrated at a point of a structure between two power supply lines of the two adjacent light units during the manufacturing of the light units. The perforation layer breaks in case of the failure of the light units and the perforation layer is by-passed by a conductive bridging layer (6). The perforation layer is formed in an electrically insulating manner. An independent claim is also included for a method for providing the failure protection for a LED or organic LED chain.