Light-Emitting Device with Microcavity and Color Filter

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Current light-emitting devices with a white-emissive element exhibit high viewing angle dependence of chromaticity and luminance, limiting their ability to produce white light with high purity and high definition, especially when compared to red- and blue-emissive elements.

Innovation Solution

A light-emitting device structure incorporating a microcavity effect with a semi-transmissive and semi-reflective electrode, combined with a color filter, is used to enhance the emission of monochromatic lights, allowing for the combination of these lights to produce white light with reduced power consumption and improved viewing angle independence.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If a white-emissive light-emitting element is used in a light-emitting device, then power consumption is reduced, but viewing angle dependence of chromaticity and luminance increases

Engineering Contradiction:

Improvepower consumptionVSAvoidviewing angle dependence of chromaticity

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The device is divided into multiple independent light-emitting elements, each optimized for specific emission colors (red, green, blue, yellow). This segmentation allows each element to be independently optimized for its emission characteristics while sharing common structural components like the light-emitting layer, reducing overall power consumption while maintaining color purity and viewing angle independence through individual microcavity optimization

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different optical path lengths are assigned to different light-emitting elements based on their specific emission wavelengths. Each element has a locally optimized microcavity structure with optical path length tailored to its emission color, achieving high color purity and reduced viewing angle dependence for each specific wavelength while maintaining overall device efficiency

Inventive Principle:

Principle #3Local quality

2Manufacturing precision

If a microcavity structure with semi-transmissive and semi-reflective electrode is used, then monochromatic light emission purity is enhanced, but device complexity increases

Engineering Contradiction:

Improvemonochromatic light emission purityVSAvoidmicrocavity structure complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

Multiple light-emitting elements with different emission colors are combined in a single device, sharing common structural components such as the light-emitting layer and substrate. The microcavity structures are integrated into this unified design, with each element having its own optimized optical path length. This merging approach achieves high monochromatic emission purity for each color while reducing overall device complexity through component sharing and unified fabrication processes

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The optical path length parameter is specifically adjusted for each light-emitting element to match its emission wavelength. By changing this critical parameter locally for each element (red, green, blue, yellow) while maintaining the same microcavity structure design, the patent achieves high monochromatic emission purity without proportionally increasing device complexity, as the structural framework remains consistent across all elements

Inventive Principle:

Principle #35Parameter changes

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 proposed solution enables high-purity monochromatic light emission, broad spectral range for white light, and low viewing-angle dependence of chromaticity and luminance, achieving high-definition displays with reduced power consumption.

Implementation Method 1

Methodology Applied

Scientific EffectMicrocavity effect: Interference

Implementation Method 2

voltage application between electrodes between which a light-emitting layer is provided causes recombination of electrons and holes injected from the electrodes, which leads a light-emitting substance that is an organic compound to an excited state, and the return from the excited state to the ground state is accompanied by light emission

Methodology Applied

Scientific EffectElectroluminescence: Electroluminescence

Implementation Method 3

combined with a color filter, is used to enhance the emission of monochromatic lights

Methodology Applied

Scientific EffectOptical filtering: Filter (optical)

Data Source

PatentUS10109683B2Light-emitting device comprising light-emitting element that is optically optimized independently

Publication Date: 2018.10.23 SEMICON ENERGY LAB CO LTD

AI summary

Provided is a light-emitting device which can emit monochromatic lights with high color purity due to a microcavity effect and which can provide a white light with a broad spectrum when the monochromatic lights are combined. The light-emitting device has a red-, green-, blue-, and yellow-emissive light-emitting elements each of which has a reflective electrode and a semi-transmissive and semi-reflective electrode. The red-, green-, blue-, and yellow-emissive light-emitting elements have the same structure other than the reflective electrode and a layer in contact with the reflective electrode to selectively emit red, green, blue, and yellow lights, respectively. Red, green, and blue color filters are also provided over the red-, green-, blue-, light-emitting elements, respectively. An EL layer is commonly shared by the red-, green-, blue-, and yellow-emissive light-emitting elements, and the semi-transmissive and semi-reflective electrode covers an edge portion of the EL layer.