Vertical LED Display Assembly With Side-Electrode Connection

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Solution Overview

Problem

Existing display devices using liquid crystal displays require a backlight unit, increasing thickness and limiting design flexibility, while self-emitting display devices like OLEDs face issues with oxidation between organic light-emitting layers and electrodes due to water and oxygen permeation.

Innovation Solution

A display device utilizing vertical light-emitting diodes (LEDs) with a method of manufacturing that involves transferring and electrically connecting the LED elements using an adhesive layer and photolithography, reducing process time and cost while minimizing the need for additional encapsulation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If a backlight unit is used in liquid crystal display devices, then the display device can emit light, but the thickness of the display device increases

Engineering Contradiction:
Improvelight emissionVSAvoidthickness
Core Design Contradiction:
Illumination intensityVSLength of stationary object

Solution Approach 1:

The patent extracts the light-emitting function from a separate backlight unit and integrates it directly into the display device structure using self-emitting elements (OLED or LED). This eliminates the need for a dedicated backlight unit, thereby reducing overall thickness while maintaining light emission capability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of using a non-self-emitting liquid crystal display that requires an external backlight, the patent inverts the approach by using self-emitting elements (OLED or LED) that generate their own light. This fundamental inversion eliminates the backlight unit requirement and reduces thickness.

Inventive Principle:
Principle #13The other way round (Inversion)

2Length of stationary object

If organic light-emitting layers are used in self-emitting display devices, then the display device can be made thinner, but oxidation occurs between the organic light-emitting layer and electrode due to water and oxygen permeation

Engineering Contradiction:
ImprovethicknessVSAvoidoxidation resistance
Core Design Contradiction:
Length of stationary objectVSReliability

Solution Approach 1:

The patent changes the material parameter from organic light-emitting layer to inorganic light-emitting element (LED). This material substitution fundamentally alters the chemical stability characteristics, providing resistance against oxidation and water/oxygen permeation while maintaining the thin-form-factor advantage.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs composite material structures including inorganic light-emitting elements combined with appropriate encapsulation or protective layers. This composite approach provides both the desired thin profile and enhanced resistance to oxidation and environmental degradation.

Inventive Principle:
Principle #40Composite materials

3Reliability

If traditional methods are used to install LED elements in panels, then reliable electrical connection can be achieved, but the process time and manufacturing cost increase

Engineering Contradiction:
Improveelectrical connectionVSAvoidprocess time
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent merges the electrical connection process with the LED element installation process. By integrating the bonding and electrical connection steps into a single operation, the patent reduces overall process time while maintaining reliable electrical connection between LED elements and the panel.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent performs preliminary preparation of bonding surfaces and electrical connection interfaces before final LED element installation. This preliminary action ensures that when the LED elements are installed, reliable electrical connection is achieved more efficiently, reducing overall process time.

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 display device achieves reduced thickness, increased design flexibility, and improved reliability by using inorganic LED elements, while the manufacturing method allows for faster production and lower costs compared to traditional methods.

Implementation Method 1

transferred to a substrate including a pixel circuit

Methodology Applied
Scientific EffectAdhesive bonding: Adhesive

Data Source

PatentEP3657542B1Display device and method of manufacturing the same
Publication Date: 2025.05.28 LG DISPLAY CO LTD
  • EP3657542B1 patent drawingFigure 1
  • EP3657542B1 patent drawingFigure 2
  • EP3657542B1 patent drawingFigure 3

AI summary

A display device (100) and a method of manufacturing the same are provided. A display device (100) includes: a substrate (110), a pixel circuit (PC) on the substrate (110), the pixel circuit (PC) including: a gate electrode (GE), a drain electrode (DE), and a source electrode (SE), a vertical LED element (150) on the substrate (110), the vertical LED element (150) including: a first electrode (151), an active layer (152) under the first electrode (151), and a second electrode (153) under the active layer (152), an encapsulation film (155) surrounding the vertical LED element (150), the encapsulation film (155) exposing a portion of a side of the second electrode (153), a first connection electrode (PE) electrically connected to the first electrode (151), and a second connection electrode (CE) electrically connected to the second electrode (153).