LED Array Failure Mitigation via Redundant Power Strings

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Solution Overview

Problem

Interconnected LED arrays in lighting devices are prone to performance degradation or failure due to faults in individual LEDs, leading to perceptible disruptions in illumination intensity and uniformity, and replacement of faulty LEDs is often impractical.

Innovation Solution

The implementation of multiple power strings with light-emitting elements connected in series, featuring failure-mitigation elements that compensate for failed LEDs, allowing continued operation of remaining elements and minimizing performance impact, along with reserve power strings and controllers for detecting failures and activating redundant strings.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If multiple LEDs are interconnected in arrays to provide desired light output, then illumination intensity and efficiency are improved, but reliability deteriorates because a single LED failure can degrade performance of other LEDs or shut off entire groups

Engineering Contradiction:

Improvelight outputVSAvoidsystem reliability

Core Design Contradiction:

Illumination intensityVSReliability

Solution Approach 1:

The LED array is divided into multiple independent strings, where each string contains multiple LEDs connected in series. This segmentation allows individual strings to fail independently without affecting other strings, thereby maintaining overall system reliability while preserving illumination output.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different strings are configured with different numbers of LEDs or different connectivity patterns to create local variations in the system. This allows the failure of one string to be compensated by adjusting or reconfiguring other strings, maintaining overall illumination performance despite localized failures.

Inventive Principle:

Principle #3Local quality

2Use of energy by moving object

If LEDs are connected in series on power conductors to improve current efficiency, then energy efficiency is improved, but ease of repair deteriorates because replacement of faulty LEDs becomes impractical once integrated into the system

Engineering Contradiction:

Improveenergy efficiencyVSAvoidLED replacement

Core Design Contradiction:

Use of energy by moving objectVSEase of repair

Solution Approach 1:

Redundant LEDs are pre-installed in the array during manufacturing, positioned to replace potential failures before they occur. This preliminary preparation allows for easy replacement of faulty LEDs by simply activating a pre-positioned redundant LED, maintaining ease of repair while preserving energy efficiency through series connections.

Inventive Principle:

Principle #10Preliminary action

3Reliability

If redundant LEDs are added to compensate for failures, then reliability is improved, but device complexity increases due to additional elements and interconnections

Engineering Contradiction:

Improvefailure mitigationVSAvoidarray complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

Redundant LEDs are merged with the existing LED array structure, sharing common power conductors and control circuits. This integration approach allows reliability improvement through redundancy while minimizing additional complexity by utilizing existing system resources rather than adding completely separate backup systems.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS8653539B2Failure mitigation in arrays of light-emitting devices

Publication Date: 2014.02.18 COOLEDGE LIGHTING

AI summary

In accordance with certain embodiments, an illumination system comprising a plurality of power strings features elements facilitating compensation for failure of one or more light-emitting elements connected along each power string.