LED Fixture Lifetime Extension via Redundant Driver Segmentation

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Solution Overview

Problem

Conventional LED light fixtures have limited lifetimes due to lumen depreciation, making replacement difficult and costly, especially in inaccessible locations like highway signage and hazardous areas, as they typically use a single driver and LED board, which fails or decreases in brightness over time.

Innovation Solution

Implementing multiple LED drivers and multi-chip LED packages with a central or distributed controller that activates and deactivates drivers/lamps based on predetermined operating parameters, extending the fixture's lifetime by switching to redundant components when degradation is detected, and using multi-lamp/multi-chip drivers to maintain initial light levels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of stationary object

If a single LED driver and single LED board are used in a light fixture, then the device complexity is reduced and ease of manufacture is improved, but the duration of action (lifetime) is limited due to lumen depreciation

Engineering Contradiction:

Improvefixture lifetimeVSAvoidnumber of drivers and LED boards

Core Design Contradiction:

Duration of action of stationary objectVSDevice complexity

Solution Approach 1:

The light fixture is divided into multiple independent modules, each consisting of an LED driver and an LED board. Each module can operate independently, and when one module degrades, others continue to provide light output. This segmentation allows the fixture lifetime to be extended beyond the lifetime of individual LED components.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Redundant LED modules are pre-installed in the fixture before deployment. When the primary LED modules experience lumen depreciation, the controller automatically activates the pre-installed redundant modules to maintain the required light output level, avoiding the need for immediate replacement.

Inventive Principle:

Principle #10Preliminary action

2Duration of action of stationary object

If multiple LED drivers and LED boards are used to extend fixture lifetime, then the duration of action is improved, but the device complexity and difficulty of repair increase

Engineering Contradiction:

Improvefixture lifetimeVSAvoidreplacement difficulty

Core Design Contradiction:

Duration of action of stationary objectVSEase of repair

Solution Approach 1:

The fixture incorporates an automatic control system that monitors the light output of each LED module and automatically activates redundant modules when degradation is detected. This self-service capability eliminates the need for manual intervention or monitoring, and the system automatically maintains the required light output level without user involvement.

Inventive Principle:

Principle #25Self-service

3Illumination intensity

If LED current is increased to maintain brightness, then the illumination intensity is maintained, but the temperature increases and reduces LED efficiency and lifetime

Engineering Contradiction:

Improvelight brightnessVSAvoidLED operating temperature

Core Design Contradiction:

Illumination intensityVSTemperature

Solution Approach 1:

The total light output requirement is distributed across multiple LED modules instead of increasing the current through a single module. Each module operates at its optimal current level, avoiding excessive temperature rise, while the combined output of multiple modules maintains the required overall illumination intensity.

Inventive Principle:

Principle #1Segmentation

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 solution significantly extends the operational life of LED fixtures by 2-3 times, reducing replacement frequency and associated costs, while maintaining light intensity through sequential activation of redundant components and concurrent driving of depreciated LEDs.

Implementation Method 1

LEDs have become a popular choice for light fixtures due to their relatively inexpensive cost, low voltage requirements, compact size, and longer operating lifetime

Methodology Applied

Scientific EffectLight emitting diode (LED): Light Emitting Diode

Implementation Method 2

The operating lifetime of an LED fixture is limited in part due to the decrease in output light intensity of the LEDs over time. This decrease or lumen depreciation is affected by temperature

Methodology Applied

Scientific EffectLumen depreciation:

Data Source

PatentUS8242927B2Extended life LED fixture with central controller and LED lamps

Publication Date: 2012.08.14 ABL IP HLDG LLC

AI summary

An LED fixture includes multiple LED drivers and multiple LED lamps so that the lifetime of the fixture is a multiple of the lifetime of a conventional fixture that uses only a single LED driver. A central controller activates and deactivates the LED drivers so that the different LED lamps are driven sequentially. An optional multi-lamp LED driver concurrently drives multiple LED lamps that have been previously driven by the LED drivers.