Flexible Display Fabrication Using Semiconductor Light Emitting Devices

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Solution Overview

Problem

Current display technologies, such as LCDs and AMOLEDs, face challenges including slow response time, limited flexibility, short lifespan, and low yield, while semiconductor light emitting devices struggle to achieve high definition and flexibility in display devices.

Innovation Solution

A method for fabricating a display device using a semiconductor light emitting device with a flexible substrate and a phosphor layer formed using light emitted from the semiconductor light emitting devices, enabling high definition and flexibility through a novel fabrication process that includes a conductive adhesive layer and anisotropic conductive films for electrical connection and a phosphor layer formed by curing photosensitive materials with emitted light.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If semiconductor light emitting devices are used to achieve flexibility, then flexibility is improved, but manufacturing precision and high definition capabilities deteriorate

Engineering Contradiction:
ImproveflexibilityVSAvoidhigh definition capability
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The display device is divided into multiple sub-pixels (red, green, blue) that are arranged in a matrix pattern. Each sub-pixel contains a semiconductor light emitting device with specific phosphor materials, allowing the overall display to achieve high definition through precise spatial segmentation while maintaining flexibility at the device level

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different phosphor materials are selectively applied to different regions (sub-pixels) of the semiconductor light emitting device. Red phosphor, green phosphor, and blue phosphor are distributed in specific patterns to create distinct color regions, enabling high definition color display while the entire device maintains flexible characteristics

Inventive Principle:
Principle #3Local quality

2Manufacturing precision

If conventional LCD technology is used, then manufacturing precision is maintained, but response time deteriorates

Engineering Contradiction:
Improvedisplay qualityVSAvoidresponse time
Core Design Contradiction:
Manufacturing precisionVSSpeed

Solution Approach 1:

The patent replaces the liquid crystal mechanical rotation system with semiconductor light emitting devices that directly emit light through electroluminescence. This substitution eliminates the slow mechanical response of LCD molecules and achieves fast response times while maintaining precise control over light emission through electrical signals

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

3Speed

If AMOLED technology is used, then response time is improved, but reliability and lifespan deteriorate

Engineering Contradiction:
Improveresponse timeVSAvoidlifespan
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The patent changes the material parameters from organic compounds (AMOLED) to inorganic semiconductor materials with phosphor coatings. This parameter change provides faster response times comparable to AMOLED while significantly improving reliability and lifespan through the superior stability and durability of semiconductor materials

Inventive Principle:
Principle #35Parameter changes

4Manufacturing precision

If external exposure devices are used to cure phosphor layers, then manufacturing precision is improved, but device complexity increases

Engineering Contradiction:
Improvephosphor layer formationVSAvoidproduction process
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The semiconductor light emitting devices are used to emit light that cures the photosensitive phosphor materials themselves. This self-service approach eliminates the need for separate external exposure devices, reducing production process complexity while maintaining precise phosphor layer formation through the devices' own light emission

Inventive Principle:
Principle #25Self-service

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 provides a flexible display device with high definition capabilities, improved response time, and extended lifespan by utilizing semiconductor light emitting devices with a phosphor layer formed using self-emitted light, eliminating the need for external exposure devices and reducing production costs.

Implementation Method 1

light emitting diodes (LEDs) are light emitting devices for converting an electrical current to light

Methodology Applied
Scientific EffectElectroluminescence: Electroluminescence

Implementation Method 2

a phosphor layer formed using light emitted from the semiconductor light emitting devices

Methodology Applied
Scientific EffectPhotoluminescence: Photoluminescence

Data Source

PatentEP3114899B1Method of fabricating a display device using semiconductor light emitting device
Publication Date: 2021.04.28 LG ELECTRONICS INC
  • EP3114899B1 patent drawingFigure 1~2
  • EP3114899B1 patent drawingFigure 3a~5a
  • EP3114899B1 patent drawingFigure 5b~5c

AI summary

A display device including a wiring substrate having a first substrate layer and a second substrate layer, a conductive adhesive layer configured to cover the wiring substrate, a plurality of semiconductor light emitting devices coupled to the conductive adhesive layer and electrically connected to a first electrode and a second electrode. Further, the first electrode is disposed on the first substrate layer, and the second substrate layer has one surface facing the conductive adhesive layer and the other surface covering the first electrode, and an auxiliary electrode electrically connected to the first electrode and the second electrode are disposed on one surface of the second substrate layer.