Elliptical Micro-LED Package Layout With Common Electrode Wiring

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Solution Overview

Problem

Micro-LED display manufacturing faces challenges in transfer speed, high transfer error rates, long process times, and reduced color gamut due to non-uniform DEP forces and the need for separate assembly of red, green, and blue light emitting devices, which limits the ability to achieve ultra-high resolution.

Innovation Solution

A semiconductor light emitting device package with an elliptical shape and a common electrode wiring system that connects multiple light emitting devices, allowing for simultaneous assembly and improved electrical connections, along with a color conversion layer for enhanced color representation, and a magnetic layer for increased assembly speed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If self-assembly method is used to transfer micro-LEDs to display panel, then transfer speed is improved, but transfer error rate increases resulting in low transfer yield

Engineering Contradiction:
Improvetransfer speedVSAvoidtransfer yield
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The invention divides the transfer process into two distinct stages: a picking process where micro-LEDs are collected onto a carrier substrate, and a placing process where the carrier substrate is transferred to the display panel. This segmentation allows each process to be optimized independently, maintaining high transfer speed while improving transfer yield by reducing errors in the complex placement operation.

Inventive Principle:
Principle #1Segmentation

2Manufacturing precision

If red, green, and blue light emitting devices are assembled separately, then assembly precision is maintained, but process time becomes very long

Engineering Contradiction:
Improveassembly precisionVSAvoidprocess time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The invention merges the assembly of red, green, and blue light emitting devices into a single simultaneous self-assembly process. All three types of micro-LEDs are transferred together onto the display panel in one operation, dramatically reducing process time while maintaining assembly precision through the use of a carrier substrate that holds all devices in their correct positions.

Inventive Principle:
Principle #5Merging (Combining)

3Loss of time

If simultaneous assembly of red, green, and blue light emitting devices is performed, then process time is shortened, but color gamut is lowered due to different light amounts

Engineering Contradiction:
Improveprocess timeVSAvoidcolor gamut
Core Design Contradiction:
Loss of timeVSManufacturing precision

Solution Approach 1:

The invention applies local quality by providing individual light amount adjustment mechanisms for each color of micro-LED. After simultaneous assembly, the light output of red, green, and blue devices can be independently tuned to achieve balanced color reproduction and maintain wide color gamut, despite the different inherent characteristics of each micro-LED type.

Inventive Principle:
Principle #3Local quality

4Length of moving object

If distance between assembly holes of sub-pixels is reduced, then pixel size is reduced, but ultra-high resolution cannot be achieved due to limitations

Engineering Contradiction:
Improvepixel sizeVSAvoidresolution
Core Design Contradiction:
Length of moving objectVSManufacturing precision

Solution Approach 1:

The invention uses a carrier substrate as a template or copy that contains pre-formed assembly holes arranged in the desired ultra-high resolution pattern. This carrier substrate serves as a master copy that can be replicated and transferred to the display panel, enabling the formation of pixels at distances smaller than what could be achieved through direct writing or traditional assembly methods.

Inventive Principle:
Principle #26Copying

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 solution enhances assembly speed, reduces defects, and improves color accuracy, enabling the production of high-resolution micro-LED displays by simplifying the assembly process and ensuring precise electrical connections and color consistency.

Implementation Method 1

a common electrode wiring on the first region of the first layer; a plurality of electrode wirings on upper sides of the plurality of semiconductor light emitting devices; and a plurality of electrode pads on the second region of the first layer

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 2

a magnetic layer for increased assembly speed

Methodology Applied
Scientific EffectMagnetic force: Magnetic Field

Data Source

PatentEP4312269A1A semiconductor light emitting device package and a display device
Publication Date: 2024.01.31 LG ELECTRONICS INC
  • EP4312269A1 patent drawingFigure 1
  • EP4312269A1 patent drawingFigure 2
  • EP4312269A1 patent drawingFigure 3

AI summary

A semiconductor light emitting device package can include a first layer having a first region and a second region surrounding the first region, a common electrode wiring on the first region of the first layer, a plurality of semiconductor light emitting devices on the common electrode wiring, a plurality of electrode wirings on upper sides of the plurality of semiconductor light emitting devices, a plurality of electrode pads on the second region of the first layer, and a second layer on the plurality of semiconductor light emitting devices, the plurality of electrode wirings, and the plurality of electrode pads. The first layer and the second layer can have an elliptical shape. The plurality of electrode pads can include a first electrode pad, a second electrode pad, a third electrode pad, and at least one or more common electrode pads. The first electrode pad, the second electrode pad, and the third electrode pad can be configured to be disposed on the second region located on the minor axis of the elliptical shape. The common electrode pad can be configured to be disposed on the second region located on the major axis of the elliptical shape. The common electrode wiring can be configured to commonly connect lower sides of the plurality of semiconductor light emitting devices to the common electrode pad.