OLED Lighting Panel Outcoupling Enhancer Thermal Management

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Solution Overview

Problem

Existing OLED lighting panels face thermal management challenges, particularly at high luminous emittances, leading to increased junction temperatures and reduced panel lifetimes, which can result in illumination non-uniformities and decreased performance.

Innovation Solution

The use of high internal quantum efficiency phosphorescent OLEDs with an outcoupling enhancer optically coupled to each device, eliminating the need for heat management structures by minimizing heat generation through efficient light outcoupling and reducing resistive power losses in bus lines and electrodes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If conventional OLED lighting panels are operated at high luminous emittance, then light output is improved, but junction temperature increases leading to reduced panel lifetime

Engineering Contradiction:
Improveluminous emittanceVSAvoidpanel lifetime
Core Design Contradiction:
Illumination intensityVSReliability

Solution Approach 1:

The patent changes the optical coupling parameters by introducing an outcoupling enhancer with specific refractive index properties and structural configurations (microlens arrays, photonic crystals) to modify light extraction efficiency. This allows operating at high luminous emittance while controlling junction temperature through optimized optical parameters rather than reducing light output

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces thermal management structures (heat sinks, cooling systems) with an optical management system (outcoupling enhancer) that addresses the root cause of heating by improving light extraction efficiency. This substitutes a mechanical/thermal solution with an optical solution that prevents heat generation rather than managing it after the fact

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Illumination intensity

If conventional OLED lighting panels are operated at high luminous emittance, then light output is improved, but illumination uniformity deteriorates due to thermal effects

Engineering Contradiction:
Improveluminous emittanceVSAvoidillumination uniformity
Core Design Contradiction:
Illumination intensityVSStability of the object's composition

Solution Approach 1:

The outcoupling enhancer modifies the optical parameters of the OLED system to achieve uniform light extraction across the panel surface. By using structured surfaces (microlens arrays, photonic crystals) with specific geometric parameters, the system maintains uniform illumination even at high luminous emittance where conventional panels would exhibit thermal non-uniformity

Inventive Principle:
Principle #35Parameter changes

3Temperature

If heat management structures are added to OLED lighting panels, then junction temperature is controlled, but device complexity increases

Engineering Contradiction:
Improvejunction temperatureVSAvoidstructure complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The patent extracts and removes the need for separate heat management structures by integrating thermal control functionality into the optical outcoupling layer. The outcoupling enhancer serves dual purposes: improving light extraction and preventing heat generation, thereby eliminating the need for additional thermal management components

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The outcoupling enhancer performs multiple functions simultaneously: it enhances light extraction efficiency, controls junction temperature, and maintains illumination uniformity. This multi-functional component replaces what would traditionally require separate optical and thermal management systems

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Illumination intensity

If light outcoupling efficiency is improved, then luminous emittance is increased, but heat generation is reduced

Engineering Contradiction:
Improveluminous emittanceVSAvoidheat generation
Core Design Contradiction:
Illumination intensityVSLoss of energy

Solution Approach 1:

The patent converts the harmful effect of trapped light (which becomes heat) into a beneficial effect by using the outcoupling enhancer to extract this trapped light productively. The light that would have been wasted and converted to heat is instead extracted to increase luminous emittance, thereby converting a harmful energy loss into a useful output

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

This approach allows for a luminous emittance of at least 9,000 lm/m² with a junction temperature rise of less than 10°C, extending panel lifetime and ensuring the panel remains cool to the touch, while maintaining high luminance uniformity and efficiency.

Implementation Method 1

OLEDs make use of thin organic films that emit light when voltage is applied across the device

Methodology Applied
Scientific EffectElectroluminescence: Electroluminescence

Implementation Method 2

An outcoupling enhancer is optically coupled to each organic light emitting device

Methodology Applied
Scientific EffectOptical outcoupling:

Data Source

PatentEP2572391B1Organic light emitting device lighting panel
Publication Date: 2020.11.18 UNIVERSAL DISPLAY CORP
  • EP2572391B1 patent drawingFigure 1
  • EP2572391B1 patent drawingFigure 2
  • EP2572391B1 patent drawingFigure 3

AI summary

A first device that may include one or more organic light emitting devices. At least 65 percent of the photons emitted by the organic light emitting devices are emitted from an organic phosphorescent emitting material. An outcoupling enhancer is optically coupled to each organic light emitting device. In one embodiment, the light panel is not attached to a heat management structure. In one embodiment, the light panel is capable of exhibiting less than a 10 degree C rise in junction temperature when operated at a luminous emittance of 9,000 lm/m2 without the use of heat management structures, regardless of whether the light panel is actually attached to a heat management structure or not. The light panel may be attached to a heat management structure. The light panel may be not attached to a heat management structure.