Current-Spreading Layer Width Tuning for RGB Display Emitters

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Solution Overview

Problem

Current display devices face challenges in optimizing the luminous efficiency of light-emitting elements, particularly for red light, due to limitations in current-spreading layer design, which affects the emission efficiency across different wavelengths.

Innovation Solution

The proposed solution involves a light-emitting element structure with varying widths of current-spreading layers for different light-emitting elements, where the width of the current-spreading layer is adjusted based on the luminous efficiency of each element, and the indium content in the active layers is optimized to enhance emission efficiency, particularly for red, green, and blue light.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If the current-spreading layer width is increased to improve current distribution, then the luminous efficiency improves, but the device complexity increases due to varying widths for different wavelengths

Engineering Contradiction:
Improveluminous efficiencyVSAvoiddevice complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent applies local quality by varying the width of current-spreading layers according to the specific luminous efficiency requirements of different light-emitting elements. Red light elements receive wider current-spreading layers while green and blue elements receive narrower layers, optimizing current distribution locally for each wavelength's specific needs.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes the geometric parameter (width) of the current-spreading layer to optimize luminous efficiency. By adjusting the width parameter differently for red, green, and blue light-emitting elements, the patent achieves improved energy conversion efficiency while managing device complexity through systematic parameter variation.

Inventive Principle:
Principle #35Parameter changes

2Loss of energy

If the indium content in the active layer is increased to enhance red light emission, then the luminous efficiency for red light improves, but the manufacturing precision requirements increase

Engineering Contradiction:
Improveluminous efficiencyVSAvoidindium content control
Core Design Contradiction:
Loss of energyVSManufacturing precision

Solution Approach 1:

The patent changes the compositional parameter (indium content) of the active layer to optimize red light emission efficiency. By precisely controlling the indium content in the InGaN active layer, the patent enhances carrier confinement and radiative recombination efficiency for red light wavelengths, thereby improving luminous efficiency.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses composite materials by incorporating indium into the GaN-based active layer to form InGaN quantum wells. This composite structure allows for tailored optical and electrical properties, enabling enhanced red light emission through controlled indium composition while maintaining the overall semiconductor device functionality.

Inventive Principle:
Principle #40Composite materials

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 maintains similar luminous efficiency across different wavelengths by optimizing the current-spreading layer widths and indium content, improving the overall light-emitting performance and enabling applications in high-resolution displays.

Implementation Method 1

current-spreading layers including a first current-spreading layer having a first width on the first light-emitting element and a second current-spreading layer having a second width

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 2

light-emitting elements including a first light-emitting element for emitting light of a first wavelength and a second light-emitting element for emitting light of a second wavelength

Methodology Applied
Scientific EffectElectroluminescence: Electroluminescence

Data Source

PatentEP4456135A1Display device
Publication Date: 2024.10.30 SAMSUNG DISPLAY CO LTD
  • EP4456135A1 patent drawingFigure 1
  • EP4456135A1 patent drawingFigure 2
  • EP4456135A1 patent drawingFigure 3

AI summary

The present disclosure relates to a light-emitting element structure and a display device. The display device includes light-emitting elements including a first light-emitting element for emitting light of a first wavelength and a second light-emitting element for emitting light of a second wavelength, and including current-spreading layers including a first current-spreading layer having a first width on the first light-emitting element and a second current-spreading layer having a second width that is less than the first width on the second light-emitting element, and an insulating layer between the light-emitting elements.