Radiation-Emitting Device With Layer Sequences And Intermediate Exciton Transfer

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Solution Overview

Problem

Radiation-emitting devices with fluorescent and phosphorescent emitters face challenges in achieving high efficiency and durability due to limitations in the generation and management of electromagnetic radiation, particularly in producing a consistent color impression and maintaining radiation yield over time.

Innovation Solution

A radiation-emitting device design featuring multiple layer sequences with fluorescent and phosphorescent emitters, where each layer sequence includes a combination of fluorescent and phosphorescent materials emitting in specific wavelength ranges, with intermediate layers and blocking layers to manage excitons and enhance radiation efficiency, allowing for independent control of each layer sequence and improved energy transfer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If multiple emitter layers with fluorescent and phosphorescent materials are used to improve radiation yield and efficiency, then the device complexity increases due to multiple layer sequences and intermediate layers

Engineering Contradiction:
Improveradiation yieldVSAvoiddevice complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The device is divided into multiple independent layer sequences (first layer sequence, second layer sequence) with distinct fluorescent and phosphorescent emitter layers. Each layer sequence can be independently optimized and manufactured, allowing complex functionality to be achieved through modular assembly rather than a single complex layer structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Intermediate layers are introduced between the first and second layer sequences to facilitate controlled energy transfer and exciton management. These intermediary layers enable efficient coupling between different emitter types while maintaining structural organization, reducing the complexity of direct multi-layer integration.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Illumination intensity

If fluorescent and phosphorescent emitter layers are combined to achieve specific color impressions, then the manufacturing precision requirements increase due to precise layer arrangement and exciton management

Engineering Contradiction:
Improvecolor impressionVSAvoidmanufacturing precision
Core Design Contradiction:
Illumination intensityVSManufacturing precision

Solution Approach 1:

Different layer sequences are designed with specific local qualities - the first layer sequence contains fluorescent and phosphorescent emitters for one color range, while the second layer sequence contains different emitters for another color range. This localized functional differentiation allows precise color control without requiring perfect uniformity across the entire device structure.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The intermediate layers are pre-configured with specific properties to facilitate exciton transfer before the actual emission process occurs. This preliminary arrangement of energy transfer pathways simplifies the manufacturing process by establishing predictable energy flow patterns that reduce sensitivity to minor variations in layer thickness or composition.

Inventive Principle:
Principle #10Preliminary action

3Loss of energy

If intermediate layers are introduced to manage excitons and enhance radiation efficiency, then the device complexity increases due to additional layers and energy transfer management

Engineering Contradiction:
Improveenergy lossesVSAvoiddevice complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

Intermediate layers serve as mediators for exciton transfer between fluorescent and phosphorescent emitter layers. These intermediary structures enable efficient energy transfer while maintaining clear functional separation between different emission mechanisms, reducing the need for complex direct coupling arrangements.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The energy transfer and exciton management functions are extracted into separate intermediate layers, distinct from the emitter layers themselves. This separation allows independent optimization of emission properties and energy transfer properties, simplifying the overall design by dividing complex functions into manageable, independently controllable components.

Inventive Principle:
Principle #2Taking out (Extraction)

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 design significantly enhances the yield and efficiency of emitted radiation, allows for specific color impressions, and extends the service life of the device by reducing energy losses and thermal radiation, thereby improving the overall performance and economic viability of the radiation-emitting device.

Implementation Method 1

at least a first layer with a first fluorescent emitter (301, 311, 321) that emits radiation in a first wavelength range, and at least a third layer with a second fluorescent emitter (303, 313, 323) that emits radiation in a fourth wavelength range

Methodology Applied
Scientific EffectFluorescence: Fluorescence

Implementation Method 2

a second layer with a first phosphorescent emitter (302, 312, 322) that emits radiation in a second wavelength range, and a fourth layer with a second phosphorescent emitter (304, 314, 324) that emits radiation in a third wavelength range

Methodology Applied
Scientific EffectPhosphorescence: Phosphorescence

Implementation Method 3

at least one intermediate layer (305, 315, 325) that is free of emitter material and between the first and second layer sequence is arranged

Methodology Applied
Scientific EffectExciton transfer:

Implementation Method 4

at least one blocking layer (306, 316, 326) that is arranged between the first layer and the second layer and between the second layer and the third layer of the first layer sequence and between the first layer and the second layer and between the second layer and the third layer of the second layer sequence

Methodology Applied
Scientific EffectExciton blocking:

Data Source

PatentEP2351117B1Radiation-emitting device
Publication Date: 2021.09.08 OSRAM OLED
  • EP2351117B1 patent drawingFigure 1
  • EP2351117B1 patent drawingFigure 2~3
  • EP2351117B1 patent drawingFigure 4

AI summary

The invention relates to a radiation-emitting device for emitting electromagnetic radiation that is a mixture of at least three different partial radiations of a first, second and third wavelength range. The radiation-emitting device comprises a substrate (1), a first electrode (2) and a second electrode (6), at least one first succession of layers (3) arranged between the first electrode and the second electrode and comprising at least one first layer (31) provided with a first fluorescence emitter emitting radiation in the first wavelength range, and at least one second layer (32) comprising a first phosphorescence emitter emitting radiation in the second wavelength range, at least one second succession of layers (5) comprising at least one first layer (51) provided with a second fluorescence emitter emitting radiation in the first wavelength range, and at least one second layer (52) provided with a second phosphorescence emitter emitting radiation in the third wavelength range, and at least one intermediate layer (4) free of emitter material and arranged between the first and second successions of layers.