Stacked Micro-LED Structure With Bragg Reflector for Color Angle Stability

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Solution Overview

Problem

Micro-LED displays face challenges in maintaining consistent color tone across different viewing angles due to varying radiation patterns of blue, green, and red light, which are difficult to transfer and require protection without optical distortion or luminance loss.

Innovation Solution

A light emitting device with a substrate featuring a protruding pattern, multiple sub-units, insulation layers including a distributed Bragg reflector, and connection electrodes, designed to enhance light extraction efficiency and reduce angle-dependent color tone changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If micro LEDs are arranged on a plane corresponding to each sub-pixel, then the display can show various colors by mixing blue, green, and red light, but it becomes difficult to transfer a large number of micro LEDs to a circuit board due to their small form factor

Engineering Contradiction:

Improvecolor display capabilityVSAvoidtransfer difficulty

Core Design Contradiction:

Illumination intensityVSEase of manufacture

Solution Approach 1:

The invention divides the light emitting structure into multiple sub-units (first, second, and third sub-units) that are vertically stacked instead of arranged horizontally. This segmentation allows each sub-unit to be transferred independently to the substrate, significantly reducing transfer difficulty while maintaining the capability to emit multiple colors through the stacked configuration.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention transitions from a two-dimensional planar arrangement of micro LEDs to a three-dimensional vertical stacking configuration. By arranging sub-units in the vertical dimension rather than horizontally on a plane, the device maintains color display capability while dramatically improving transferability to circuit boards.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Reliability

If a light emitting device is mounted on a circuit board, then it can be used in displays and lighting applications, but the device needs protection without optical distortion or loss of luminance

Engineering Contradiction:

Improveapplication usabilityVSAvoidluminance

Core Design Contradiction:

ReliabilityVSIllumination intensity

Solution Approach 1:

The invention introduces an encapsulant layer as an intermediary between the stacked sub-units and the external environment. This encapsulant protects the mounted device from environmental damage while being optically transparent, thus preventing both optical distortion and luminance loss.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The encapsulant acts as a protective thin film that envelops the stacked light emitting sub-units. This flexible protective layer shields the device during mounting and operation without interfering with light output, maintaining both reliability and luminance.

Inventive Principle:

Principle #30Flexible shells and thin films

3Adaptability or versatility

If radiation patterns of blue light, green light, and red light emitted from one pixel are different, then various colors can be displayed, but the color of an image changes depending on the viewing angle

Engineering Contradiction:

Improvecolor varietyVSAvoidcolor consistency

Core Design Contradiction:

Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The invention applies different optical characteristics to different sub-units in the stack. Each sub-unit is positioned and configured with specific optical properties that compensate for the inherent viewing angle dependence, creating local quality variations that result in overall color consistency across different viewing angles.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The invention modifies optical parameters such as the positioning, orientation, and optical characteristics of each sub-unit in the stack. By changing these parameters locally for each sub-unit, the device achieves consistent color output across different viewing angles while maintaining the ability to display various colors.

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 solution improves light extraction efficiency and reduces color tone variations by aligning radiation patterns, ensuring consistent color display across viewing angles.

Implementation Method 1

at least one of the first insulation layer and the second insulation layer includes a distributed Bragg reflector

Methodology Applied

Scientific EffectBragg reflection: Bragg Diffraction

Data Source

PatentUS20260082734A1Light emitting device and light emitting module having the same

Publication Date: 2026.03.19 SEOUL VIOSYS CO LTD

AI summary

A light emitting device including a substrate having a protruding pattern on an upper surface thereof, a first sub-unit disposed on the substrate, a second sub-unit disposed between the substrate and the first sub-unit, a third sub-unit disposed between the substrate and the second sub-unit, a first insulation layer at least partially in contact with side surfaces of the first, second, and third sub-units, and a second insulation layer at least partially overlapping with the first insulation layer, in which at least one of the first insulation layer and the second insulation layer includes a distributed Bragg reflector.