Light-absorption layer for high-contrast OLED displays

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Solution Overview

Problem

Conventional light-emitting devices and elements suffer from low contrast due to external light being reflected and scattered by the reflective structure, leading to reduced light-extraction efficiency and display quality.

Innovation Solution

A light-emitting element and device configuration that includes a reflective layer, a light absorption layer, a transparent first electrode, a functional layer with a light-emitting layer, and a transparent second electrode, where the light absorption layer transmits specific visible light wavelengths and absorbs others, positioned adjacent to the reflective layer and first electrode, covering the entire reflective layer in the light-emitting region to enhance contrast.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a reflective structure is used to improve light-extraction efficiency, then light-extraction efficiency is improved, but external light is reflected and scattered causing low contrast

Engineering Contradiction:

Improvelight-extraction efficiencyVSAvoidexternal light reflection and scattering

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent divides the optical functional layers into distinct segments: a reflective layer for enhancing light extraction and a separate light absorption layer for suppressing external light reflection. This segmentation allows each layer to perform its specific function without interfering with the other, resolving the contradiction between light extraction efficiency and external light management.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The light absorption layer acts as an intermediary between the reflective layer and the external environment. It selectively absorbs unwanted external light wavelengths while allowing the desired emitted light to pass through, thereby mediating the interaction between the reflective structure and external light to eliminate harmful reflections.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If a reflective structure is used to enhance light extraction, then light extraction is improved, but display contrast is reduced due to scattered external light

Engineering Contradiction:

Improvelight extraction efficiencyVSAvoiddisplay contrast

Core Design Contradiction:

ProductivityVSIllumination intensity

Solution Approach 1:

The light absorption layer is positioned specifically in the light-emitting region where external light interference occurs, providing localized suppression of unwanted reflections. This local quality approach ensures that the reflective structure can enhance light extraction in the bulk while the absorption layer handles external light interference in the critical emission zone, preserving display contrast.

Inventive Principle:

Principle #3Local quality

3Productivity

If external light is reflected by the reflective structure, then light extraction is enhanced, but discharge light has low contrast

Engineering Contradiction:

Improvelight extraction efficiencyVSAvoidlight discharge quality

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent converts the potentially harmful effect of external light reflection into a beneficial configuration by introducing the light absorption layer. This layer selectively absorbs the wavelengths of external light that would otherwise cause low-contrast discharge, while allowing the reflective layer to continue enhancing light extraction. The harmful external light reflections are transformed into absorbed energy, improving discharge quality.

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 configuration improves light-extraction efficiency and maintains high contrast and display quality even under external light, by effectively transmitting desired light wavelengths while absorbing unwanted external light, resulting in brighter and more vivid displays.

Implementation Method 1

the light absorption layer transmits at least part of the visible light of the first color and absorbs at least part of visible light other than the visible light of the first color

Methodology Applied

Scientific EffectLight absorption: Absorption (EM radiation)

Data Source

PatentUS20240357906A1Light-emitting element and light-emitting device

Publication Date: 2024.10.24 SHARP KK

AI summary

A light-emitting element includes a light absorption layer for transmitting at least part of light that is visible light of a first color emitted by a light-emitting layer in a functional layer and absorbing at least part of visible light other than the light. The light absorption layer is disposed adjacent to both a reflective layer and a first electrode and covers the entire reflective layer in a light-emitting region.