Self-Assembled LED Display Substrates for Large Flexible Panels

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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 luminous efficiency, particularly in implementing large-sized flexible displays using semiconductor light emitting elements.

Innovation Solution

A flexible display device utilizing semiconductor light emitting elements is developed, featuring a substrate with a conductive adhesive layer and a self-assembly method for assembling light emitting diodes, which allows for a high-power light emitting element array with phosphor layers to enhance luminance and color implementation, enabling a flexible and efficient display solution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If semiconductor light emitting elements are coupled to a substrate in a self-assembly manner, then flexibility and manufacturing efficiency are improved, but it is difficult to implement a large-sized display device

Engineering Contradiction:
Improvemanufacturing efficiencyVSAvoiddisplay size
Core Design Contradiction:
Ease of manufactureVSArea of stationary object

Solution Approach 1:

The patent divides the large-sized display into multiple substrates, with each substrate containing a matrix of semiconductor light emitting elements. The display is segmented into multiple manageable substrates that can be manufactured separately and then assembled together to form the complete large-sized display, resolving the contradiction between self-assembly manufacturing efficiency and large display size implementation

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from manufacturing single large substrates to manufacturing multiple smaller substrates in parallel, effectively adding a spatial dimension to the manufacturing process. This allows simultaneous production of multiple display units, achieving large overall display area while maintaining the manufacturing efficiency benefits of self-assembly methods on smaller, more manageable substrates

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Adaptability or versatility

If a blue semiconductor light emitting element is combined with a phosphor, color filter, or other structures to implement red, green, and blue colors, then color display is achieved, but luminous efficiency decreases

Engineering Contradiction:
Improvecolor display capabilityVSAvoidluminous efficiency
Core Design Contradiction:
Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The patent extracts and eliminates the phosphor and color filter layers from the display structure, using only semiconductor light emitting elements that directly emit red, green, and blue light. This removes the energy-loss mechanisms associated with phosphor conversion and color filtering, achieving full-color display through direct emission from optimized semiconductor materials while maintaining high luminous efficiency

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the material composition and structural parameters of the semiconductor light emitting elements to enable direct emission of red, green, and blue wavelengths. By modifying the semiconductor material parameters (composition, doping, layer structure) rather than using auxiliary optical layers, the system achieves color display with minimal energy loss

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If LCD technology is used, then display functionality is achieved, but response time is slow and flexibility is difficult to implement

Engineering Contradiction:
Improvedisplay functionalityVSAvoidresponse time
Core Design Contradiction:
Ease of operationVSSpeed

Solution Approach 1:

The patent replaces the mechanical liquid crystal rotation system with solid-state semiconductor light emitting elements that respond instantaneously to electrical signals. This substitution eliminates the slow mechanical response of liquid crystals while maintaining display functionality, achieving fast response times characteristic of LED technology combined with flexible substrate benefits

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

4Shape

If AMOLED technology is used, then flexibility is achieved, but lifespan is short, yield is not good, and flexibility is limited

Engineering Contradiction:
ImproveflexibilityVSAvoidlifespan
Core Design Contradiction:
ShapeVSReliability

Solution Approach 1:

The patent uses flexible thin-film substrates to carry the semiconductor light emitting elements, maintaining the flexibility and form-factor advantages of AMOLED while replacing the organic light-emitting layer with more stable inorganic semiconductor materials. This thin-film flexible substrate approach preserves bendability and flexibility while significantly improving device lifespan and manufacturing yield through the use of robust semiconductor and inorganic material systems

Inventive Principle:
Principle #30Flexible shells and thin films

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 the creation of flexible, high-luminance, and full-color displays with small-sized semiconductor light emitting elements, overcoming the limitations of existing technologies by providing a robust and efficient method for assembling and connecting light emitting elements on a flexible substrate, thus achieving improved display quality and scalability.

Implementation Method 1

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

Methodology Applied
Scientific EffectElectroluminescence: Electroluminescence

Implementation Method 2

a manufacturing method in which semiconductor light emitting elements are coupled to a substrate in a self-assembly manner has been developed

Methodology Applied
Scientific EffectSelf-assembly: Self-Assembly

Data Source

PatentEP3579663B1Display device using semiconductor light emitting element, and manufacturing method therefor
Publication Date: 2024.03.27 LG ELECTRONICS INC
  • EP3579663B1 patent drawingFigure 1
  • EP3579663B1 patent drawingFigure 2
  • EP3579663B1 patent drawingFigure 3A~3B

AI summary

The present invention relates to a display device and, more particularly, to a display device using a semiconductor light emitting element. The display device according to the present invention comprises: a substrate including a plurality of metal pads; and a green semiconductor light emitting element and a blue semiconductor light emitting element, which are electrically connected to the metal pads through self-assembly, wherein the green semiconductor light emitting element and the blue semiconductor light emitting element include identification parts having different shapes so as to be distinguishable from each other when connected to the substrate.