Micro-LED Color Conversion Layout for Lower Light Loss

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Solution Overview

Problem

Existing light-emitting devices and display devices face challenges in enhancing the light-emitting efficiency of subminiature light-emitting diodes, particularly in terms of reducing space requirements for electrodes and improving light output efficiency.

Innovation Solution

A light-emitting device is designed with a color conversion layer disposed on the same substrate as the subminiature light-emitting element, allowing for enhanced light output efficiency by minimizing the distance between the light-emitting elements and the color conversion layer, thereby reducing light loss and preventing color mixture between adjacent pixels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the LED is coupled to an electrode with conventional spacing, then the electrode space is sufficient for fabrication, but the light output efficiency is reduced due to light loss over distance

Engineering Contradiction:
Improveelectrode spaceVSAvoidlight loss
Core Design Contradiction:
Ease of manufactureVSLoss of energy

Solution Approach 1:

The patent transitions from a planar electrode arrangement to a three-dimensional vertical stacking configuration. The LED, electrode, and color conversion layer are stacked in the vertical dimension, allowing light to travel a minimal distance directly from the LED to the color conversion layer without lateral spreading, thereby reducing light loss while maintaining fabrication feasibility.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent implements a nested structure where the color conversion layer is positioned directly on top of the electrode, which in turn is positioned directly on top of the LED. This nested arrangement minimizes the distance between components and eliminates unnecessary lateral light travel, improving light output efficiency while keeping the overall device footprint compact.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Productivity

If the distance between LED and color conversion layer is reduced, then light output efficiency is enhanced, but color mixture between adjacent pixels may occur

Engineering Contradiction:
Improvelight output efficiencyVSAvoidcolor mixture prevention
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent introduces a pixel-defining layer that segments the device into discrete pixel regions. This layer creates physical boundaries between adjacent pixels, confining the light path within each pixel's designated area. The segmentation allows the LED and color conversion layer to be positioned close together for high efficiency while preventing light from spilling into adjacent pixels, thus avoiding color mixture.

Inventive Principle:
Principle #1Segmentation

3Area of stationary object

If subminiature LED is used, then space is reduced, but light emitting efficiency is difficult to enhance

Engineering Contradiction:
Improvedevice areaVSAvoidlight emitting efficiency
Core Design Contradiction:
Area of stationary objectVSProductivity

Solution Approach 1:

The patent replaces conventional lateral light guidance mechanisms with a vertical light path configuration. By stacking the LED, electrode, and color conversion layer vertically, the system eliminates the need for complex lateral light management structures, achieving high light emitting efficiency in a compact subminiature form factor.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent positions the color conversion layer directly on the electrode before final device assembly, pre-establishing the optimal light path. This preliminary arrangement ensures that light from the subminiature LED immediately encounters the color conversion layer without deviation, maximizing light emitting efficiency despite the small device size.

Inventive Principle:
Principle #10Preliminary action

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 enhances the light output efficiency of the light-emitting device by directly incident light on the color conversion layer without loss, simplifies the fabrication process, and prevents color mixture between sub-pixels, resulting in improved color reproducibility and efficiency.

Implementation Method 1

a color conversion layer disposed on the same substrate as the subminiature light-emitting element

Methodology Applied
Scientific EffectPhotoluminescence: Photoluminescence

Data Source

PatentEP3832739B1Light-emitting device and display device comprising same
Publication Date: 2025.07.16 SAMSUNG DISPLAY CO LTD
  • EP3832739B1 patent drawingFigure 1A~1B
  • EP3832739B1 patent drawingFigure 2
  • EP3832739B1 patent drawingFigure 3A

AI summary

A light emitting device may include: a substrate; at least one light emitting element located on the substrate and configured to emit light; a first electrode and a second electrode spaced from each other by a predetermined distance with the light emitting element interposed therebetween; a color conversion layer located on the substrate and configured to convert light emitted from the light emitting element into light having a specific color; a first contact electrode configured to electrically couple the first electrode with a first end of the light emitting element; and a second contact electrode configured to electrically couple the second electrode with a second end of the light emitting element. In a plan view, the color conversion layer may be spaced from the light emitting element by a predetermined distance and overlaps with any one of the first and the second contact electrodes.