Self-Assembled LED Display Transfer for Precise Sub-Pixel Alignment

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Current display devices using light emitting diodes (LEDs) face challenges in reducing transferring errors, improving production efficiency, minimizing manufacturing costs, and minimizing visible recognition of wavelength deviation distribution, particularly in aligning LEDs during the manufacturing process.

Innovation Solution

A display device design that includes a substrate with sub-pixels, an adhesive layer, and self-assembled LEDs, where the LEDs are connected via a reflective electrode and planarization layers, and a manufacturing method that uses an electric field to align and transfer LEDs onto the adhesive layer, reducing alignment errors and increasing efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional transferring methods are used for LEDs, then the manufacturing process can be completed, but transferring errors and alignment errors occur reducing manufacturing precision

Engineering Contradiction:
ImproveLED alignment precisionVSAvoidtransferred LED reliability
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The patent applies preliminary action by pre-forming protrusions on the donor substrate before transferring LEDs. These protrusions are prepared in advance to receive and align LEDs during the transferring process, ensuring precise positioning without requiring complex real-time alignment mechanisms.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent uses an adhesive layer as an intermediary between the donor substrate and the substrate. This adhesive layer facilitates the transferring process by enabling controlled release and precise placement of LEDs, reducing direct contact and potential damage while improving alignment accuracy.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If multiple transferring processes are used for LEDs, then complete coverage can be achieved, but production efficiency decreases and manufacturing time increases

Engineering Contradiction:
Improveproduction efficiencyVSAvoidmanufacturing time
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The patent merges multiple transferring operations into a single process by arranging multiple LEDs on the donor substrate simultaneously and transferring them together. This combining of operations reduces the total number of transferring steps required, thereby improving production efficiency and reducing manufacturing time.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent applies preliminary action by pre-arranging multiple LEDs in their final positions on the donor substrate before the transferring process. This preliminary positioning eliminates the need for sequential placement operations, significantly reducing the total manufacturing time and improving productivity.

Inventive Principle:
Principle #10Preliminary action

3Ease of manufacture

If conventional alignment methods are used for LEDs, then the process can be completed, but alignment errors occur increasing manufacturing cost

Engineering Contradiction:
Improvemanufacturing costVSAvoidLED alignment precision
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent applies self-service by designing protrusions on the donor substrate that automatically guide and position LEDs during the transferring process. The geometric features of the protrusions and LEDs work together to achieve precise alignment without requiring external alignment equipment or complex procedures, thereby reducing manufacturing cost while maintaining high precision.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent replaces complex mechanical alignment systems with a simpler geometric interlocking mechanism. The protrusions and corresponding recesses create a mechanical guide system that passively ensures precise positioning, eliminating the need for expensive alignment instruments and reducing manufacturing complexity and cost.

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

4Manufacturing precision

If LEDs are transferred without self-assembly, then the process is simpler, but alignment errors and wavelength deviation become visible

Engineering Contradiction:
ImproveLED positioning accuracyVSAvoidtransferring process complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies self-service by enabling LEDs to self-align and self-position on the protrusions during the transferring process. The geometric features guide the LEDs into correct positions automatically, achieving high positioning accuracy without requiring complex external alignment systems or procedures.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent applies parameter changes by utilizing the geometric parameters of the protrusions (size, shape, position) to control LED placement. By carefully designing these geometric parameters, the system achieves precise LED positioning while maintaining a relatively simple transferring process.

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 effectively reduces alignment errors, improves production efficiency, and minimizes visible wavelength deviation, leading to cost-effective and high-quality LED display devices with improved color uniformity and luminance.

Implementation Method 1

self-assembling a plurality of light emitting diodes on an assembling substrate; transferring the plurality of light emitting diodes which is self-assembled on the assembling substrate onto a donor; and transferring the plurality of light emitting diodes on the donor onto an adhesive layer of the display panel

Methodology Applied
Scientific EffectElectric field: Electric Field

Implementation Method 2

self-assembling a plurality of light emitting diodes on an assembling substrate

Methodology Applied
Scientific EffectSelf-assembly: Self-Assembly

Implementation Method 3

an adhesive layer disposed on the substrate; and a plurality of light emitting diodes self-assembled which are transferred onto the adhesive layer

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP4394873A1LED based display device and method of manufacturing the same
Publication Date: 2024.07.03 LG DISPLAY CO LTD
  • EP4394873A1 patent drawingFigure 1
  • EP4394873A1 patent drawingFigure 2A
  • EP4394873A1 patent drawingFigure 2B

AI summary

According to an aspect of the present disclosure, a display device (100) includes a substrate (110) in which a pixel (PX) including a plurality of sub pixels (SP1, SP2, SP3) is defined; an adhesive layer (116) disposed on the substrate; and a plurality of light emitting diodes (120, 130, 140) self-assembled which are transferred onto the adhesive layer and disposed in the plurality of sub pixels. Accordingly, each light emitting diode (120, 130, 140) is disposed on the adhesive layer (116) to fix the light emitting diode which is transferred from a donor (300). Also disclosed is a method of manufacturing said display device (100).