Stacked Light Emitting Elements for Color Display Without Conversion Layers

Solution Overview

Problem

Current display devices for virtual and augmented reality, such as head-mounted displays, require multiple light emitting elements to produce a wide range of colors, often relying on wavelength conversion layers which reduce light efficiency and increase complexity.

Innovation Solution

A display device design featuring a substrate with pixel electrodes and light emitting elements, including a first and second stack configured to emit different colors, with tunnel functional layers between them, allowing for the emission of various wavelengths without a wavelength conversion layer, thereby enhancing light efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a wavelength conversion layer is used to display various colors from single-color light emitting elements, then color display capability is improved, but light efficiency deteriorates and device complexity increases

Engineering Contradiction:

Improvecolor display capabilityVSAvoidlight efficiency

Core Design Contradiction:

Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The light emitting element is divided into multiple stacks, where each stack contains active layers that emit different colors. This segmentation allows each stack to independently emit specific wavelengths without requiring wavelength conversion, thereby improving light efficiency while maintaining color display capability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Multiple stacks within a single light emitting element are designed to emit different colors (e.g., blue, green, red), enabling one light emitting element to perform the function of multiple single-color elements. This multi-functionality eliminates the need for wavelength conversion layers while maintaining versatile color display.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If a wavelength conversion layer is used to display various colors from single-color light emitting elements, then color display capability is improved, but device complexity increases

Engineering Contradiction:

Improvecolor display capabilityVSAvoiddevice structure complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The light emitting element is divided into multiple stacks, where each stack contains active layers that emit different colors. This segmentation allows each stack to independently emit specific wavelengths without requiring wavelength conversion, thereby improving light efficiency while maintaining color display capability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Multiple stacks within a single light emitting element are designed to emit different colors (e.g., blue, green, red), enabling one light emitting element to perform the function of multiple single-color elements. This multi-functionality eliminates the need for wavelength conversion layers while maintaining versatile color display.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Adaptability or versatility

If multiple light emitting elements are used to produce a wide range of colors, then color display capability is improved, but the number of sub-pixels and manufacturing complexity increase

Engineering Contradiction:

Improvecolor display capabilityVSAvoidmanufacturing process simplicity

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

Multiple stacks that emit different colors are merged into a single light emitting element structure, sharing common electrodes and support infrastructure. This merging reduces the total number of discrete elements and sub-pixels required, simplifying the manufacturing process while maintaining wide color gamut capability.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

Multiple stacks within a single light emitting element are designed to emit different colors (e.g., blue, green, red), enabling one light emitting element to perform the function of multiple single-color elements. This multi-functionality eliminates the need for wavelength conversion layers while maintaining versatile color display.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 solution enables the display of various colors without a wavelength conversion layer, improving light efficiency and simplifying the display device structure by allowing individual light emitting elements to emit specific colors, thus reducing the number of sub-pixels and simplifying the manufacturing process.

Implementation Method 1

tunnel functional layers between the first stack and the second stack

Methodology Applied

Scientific EffectQuantum tunneling:

Implementation Method 2

a first active layer configured to emit the first light, and the second stack includes a second active layer configured to emit the second light or the third light

Methodology Applied

Scientific EffectElectroluminescence: Electroluminescence

Data Source

PatentUS20230114923A1Display device

Publication Date: 2023.04.13 SAMSUNG DISPLAY CO LTD

AI summary

A display device comprises a substrate, a plurality of pixel electrodes on the substrate, and a plurality of light emitting elements on the plurality of pixel electrodes, wherein the plurality of light emitting elements include a first light emitting element and a second light emitting element, and each of the first light emitting element and the second light emitting element comprises a first stack configured to emit a first light, a second stack below the first stack and configured to emit a second light or a third light, and tunnel functional layers between the first stack and the second stack.