InGaN Semiconductor Light Emitting Device for Flexible Displays

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Solution Overview

Problem

Current display technologies, such as LCDs and AMOLEDs, face issues with slow response time, limited flexibility, short lifespan, and high power consumption, which are not adequately addressed by existing solutions.

Innovation Solution

A display device utilizing semiconductor light emitting devices with a composition formula of InxAlyGal-x-yN, featuring a conductive adhesive layer for electrical connection and a wavelength converter to enhance flexibility and efficiency, emitting ultraviolet light and incorporating a phosphor layer for color conversion, which also blocks UV light to prevent optical interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If liquid crystal displays (LCDs) are used, then display functionality is achieved, but response time is slow and flexibility is difficult to implement

Engineering Contradiction:
Improveresponse timeVSAvoidflexibility
Core Design Contradiction:
SpeedVSAdaptability or versatility

Solution Approach 1:

The patent replaces the mechanical liquid crystal twisting mechanism with a semiconductor light emitting device that directly converts electrical signals to light, eliminating the slow mechanical response of LCD molecules. The semiconductor device uses electroluminescence to generate light rapidly, achieving fast response times while the flexible substrate enables bending and folding capabilities.

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

Solution Approach 2:

The patent changes the fundamental operating parameters from liquid crystal optical modulation to semiconductor electroluminescence. By using InGaN semiconductor materials with specific bandgap properties, the display achieves both fast response times (microsecond range) and flexibility through the semiconductor's direct electrical-to-optical conversion mechanism.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If active matrix organic light emitting diodes (AMOLEDs) are used, then flexibility is achieved, but life span is short and yield is poor

Engineering Contradiction:
ImproveflexibilityVSAvoidlife span
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent employs composite material structure combining flexible substrate with inorganic semiconductor light emitting devices. The flexible substrate provides bending capability while the inorganic InGaN semiconductor materials provide long operational life and high reliability, overcoming the limitations of organic materials in AMOLEDs.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent replaces fragile organic light emitting materials with more durable semiconductor materials that have longer operational lifetimes. The semiconductor devices offer superior stability and resistance to degradation, achieving both flexibility and long service life.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Speed

If semiconductor light emitting devices with InGaN composition are used, then fast response time and long life span are achieved, but additional components for wavelength conversion are required

Engineering Contradiction:
Improveresponse timeVSAvoidstructure
Core Design Contradiction:
SpeedVSDevice complexity

Solution Approach 1:

The patent combines the semiconductor light emitting device with wavelength converting layers and conductive adhesive layers into an integrated structure. The InGaN semiconductor emits blue light that is converted to other wavelengths by phosphor layers, creating a compact multi-functional device that achieves fast response and long life without excessive complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The semiconductor light emitting device serves multiple functions: it provides the light source, the conductive adhesive layer provides both electrical connection and mechanical bonding, and the wavelength converting layer provides color conversion. This multi-functionality reduces the need for separate components.

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Reliability

If conductive adhesive layer with body surrounding conductors is used, then electrical connection and structural support are achieved, but UV light blocking is required to prevent optical interference

Engineering Contradiction:
Improveelectrical connectionVSAvoidoptical interference
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a UV blocking layer as an intermediary between the conductive adhesive layer and the light emitting devices. This intermediary layer selectively blocks harmful UV wavelengths while allowing visible light to pass, preventing optical interference without compromising the electrical connection function of the conductive adhesive.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent applies UV blocking properties specifically where needed - in the conductive adhesive layer and surrounding structures - while maintaining electrical conductivity in the same components. The UV blocking is localized to areas where optical interference could occur, rather than requiring complete UV filtration throughout the entire device.

Inventive Principle:
Principle #3Local quality

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 enables a flexible, high-speed display with long lifespan and low power consumption, eliminating the need for additional backlight and achieving excellent luminance and efficiency, while maintaining a compact size for high-definition image quality.

Implementation Method 1

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

Methodology Applied
Scientific EffectElectroluminescence: Electroluminescence

Implementation Method 2

a wavelength converter to convert a wavelength of light generated from the semiconductor light emitting device

Methodology Applied
Scientific EffectPhosphorescence: Phosphorescence

Data Source

PatentEP3036969B1Display device using semiconductor light emitting device
Publication Date: 2021.12.29 LG ELECTRONICS INC
  • EP3036969B1 patent drawingFigure 1~2
  • EP3036969B1 patent drawingFigure 3a~4
  • EP3036969B1 patent drawingFigure 5a~5c

AI summary

A display device according to an embodiment of the present disclosure may include a lower substrate disposed with a line electrode at an upper portion thereof, a plurality of semiconductor light emitting devices electrically connected to the line electrode to generate light, a wavelength converter disposed on the semiconductor light emitting device to convert a wavelength of light generated from the semiconductor light emitting device, and a conductive adhesive layer comprising conductors configured to electrically connect the lower substrate to the semiconductor light emitting device and a body configured to surround the conductors, wherein the semiconductor light emitting device has a composition formula of InxAlyGa1-x-yN (0≤x≤1, 0≤y≤1, 0≤x+y≤1).