Laminated Glazing Ion Control for LED Lifespan

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Solution Overview

Problem

Laminated glass panels with integrated LEDs experience significant reduction in light intensity and the appearance of brownish staining on conductive layers over time, particularly when powered with higher electrical currents, due to ion diffusion from thermoplastic interlayers, leading to reduced lifespan.

Innovation Solution

The use of a thermoplastic interlayer with specific ion concentrations (20-30 ppm Na+, 1-5 ppm K+, 5-10 ppm Ca++, and 10-20 ppm Mg++) between glass sheets in laminated glazing panels to slow down the reduction in light intensity and the appearance of colored spots, thereby extending the lifespan of the panels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional thermoplastic interlayers are used in laminated glazing with integrated LEDs, then the manufacturing process is simple and cost-effective, but the light intensity of LEDs decreases significantly over time and brownish staining appears on conductive layers

Engineering Contradiction:
ImproveLED lifespan and panel durabilityVSAvoidinterlayer material selection complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent applies parameter changes by precisely controlling the ionic composition of the thermoplastic interlayer. Specifically, it limits Na+ to 20-30 ppm, K+ to 1-5 ppm, Ca++ to 5-10 ppm, and Mg++ to 10-20 ppm. This parameter optimization resolves the contradiction by selecting interlayers with specific ionic characteristics that prevent LED degradation and conductive layer staining, thereby extending panel lifespan without complicating the manufacturing process

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs composite materials by using thermoplastic interlayers with controlled ionic compositions that combine multiple beneficial properties. These specialized interlayers resist ion migration to LEDs and conductive layers while maintaining their primary functions of lamination and safety. This composite approach improves reliability by preventing degradation mechanisms without requiring fundamentally different materials, thus maintaining ease of manufacture

Inventive Principle:
Principle #40Composite materials

2Illumination intensity

If higher electrical currents are applied to LEDs for increased light output, then illumination intensity improves, but ion diffusion from thermoplastic interlayer accelerates causing faster degradation

Engineering Contradiction:
ImproveLED light outputVSAvoidpanel lifespan under high power operation
Core Design Contradiction:
Illumination intensityVSReliability

Solution Approach 1:

The patent applies preliminary anti-action by pre-configuring the thermoplastic interlayer with optimized ionic composition before the panel is assembled and operated. By limiting Na+ to 20-30 ppm, K+ to 1-5 ppm, Ca++ to 5-10 ppm, and Mg++ to 10-20 ppm, the interlayer is prepared in advance to resist ion migration even when LEDs operate at high currents. This preliminary preparation counteracts the harmful effects of high-power operation before they can occur, allowing both high illumination intensity and long reliability

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The patent converts the potential harm of high electrical currents into a benefit by using the controlled ionic composition of the thermoplastic interlayer. Instead of allowing high currents to accelerate ion diffusion and degradation, the optimized interlayer composition ensures that even under high-power conditions, ion migration is minimized. This allows the system to benefit from high LED output while the interlayer's specific ionic characteristics prevent the usual degradation pathways

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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 specified ion composition in the thermoplastic interlayer significantly delays the decrease in light intensity and the onset of brownish staining, resulting in a longer lifespan for the laminated glazing panels compared to conventional panels.

Implementation Method 1

the light intensity of the LEDs on the panel decreases over time... an abnormal decrease in the luminous flux of the order of 70% is observed after 5000 hours of operation... the appearance of brownish coloring spots on the conductive layer at the level of the negative electrode of the LEDs after a certain time of use

Methodology Applied
Scientific EffectIon diffusion: Diffusion

Data Source

PatentEP2595807B1Glazing pane comprising a first sheet of glass and a thermoplastic interlayer
Publication Date: 2014.09.17 AGC GLASS EUROPE SA
  • EP2595807B1 patent drawingFigure 1
  • EP2595807B1 patent drawingFigure 2
  • EP2595807B1 patent drawingFigure 3

AI summary

The invention relates to a glass panel, including: a first glass sheet (2); a conductive layer (1); electric power supply tracks (11, 12) made from the conductive layer for supplying power to at least one LED (8); and at least one sheet of thermoplastic material (3). According to the invention, in such a panel, the sheet of thermoplastic material includes 20 to 30 ppm of Na+ ions, 1 to 5 ppm of K+ ions, 5 to 10 ppm of Ca++ ions, and 10 to 20 ppm of Mg++ ions.