Micro LED Electrode Pad Layout for High-Resolution Display Repair

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Solution Overview

Problem

Current display technologies, such as LCDs, face limitations in achieving small thickness, high resolution, and efficient energy use due to complex structures and the need for backlights and liquid crystal layers, while self-luminous displays with organic LEDs have durability issues and require encapsulation.

Innovation Solution

A display apparatus utilizing inorganic micro LEDs with optimized arrangements of LEDs and electrode pads, including shared cathode pads and repair LEDs, connected through anisotropic conductive films, to reduce pixel size and enhance resolution, and a manufacturing method that electrically connects LEDs to pads on a substrate, allowing for high luminance and durability without the need for encapsulation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If LCD structure with backlight, liquid crystal layer and color filter is used, then light transmission and color display are achieved, but structure complexity increases and thickness cannot be reduced

Engineering Contradiction:
Improvestructure complexityVSAvoiddisplay thickness
Core Design Contradiction:
Device complexityVSLength of stationary object

Solution Approach 1:

The patent extracts and removes the backlight unit, liquid crystal layer, and color filter from the display structure, replacing them with self-luminous micro LEDs that generate light directly at the pixel level, thereby eliminating unnecessary components and reducing overall thickness

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent transitions from a passive light-modulating system (LCD) to an active light-emitting system (micro LEDs), fundamentally changing the operating principle and enabling direct light generation without requiring separate backlight and control layers

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If organic LEDs are used for self-luminous display, then backlight and liquid crystal layer are eliminated, but durability decreases and encapsulation is required

Engineering Contradiction:
Improvestructure complexityVSAvoiddisplay durability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent changes the material parameter of the LED from organic to inorganic, which fundamentally alters the durability and stability characteristics, eliminating the need for encapsulation while maintaining self-luminous properties

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs inorganic semiconductor materials with specific crystal structures that combine high durability, stability, and efficiency, replacing organic materials that require protective encapsulation

Inventive Principle:
Principle #40Composite materials

3Manufacturing precision

If micro LED size is reduced for high resolution, then pixel density increases, but arrangement optimization becomes critical to maintain electrical connection reliability

Engineering Contradiction:
Improvepixel resolutionVSAvoidelectrical connection reliability
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The patent segments the electrode pads into multiple types (first anode pads, second anode pads, cathode pads, repair anode pads) arranged in specific patterns, allowing independent optimization of each segment's function and position to maintain reliability at high resolutions

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces anisotropic conductive films as intermediary connection layers between the micro LEDs and electrode pads, providing reliable electrical connection while accommodating misalignment and enabling flexible arrangement optimization

Inventive Principle:
Principle #24Intermediary (Mediator)

4Ease of manufacture

If shared cathode pads are used to connect multiple LEDs, then manufacturing complexity is reduced, but voltage distribution control becomes more challenging

Engineering Contradiction:
Improvemanufacturing complexityVSAvoidvoltage control complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent segments the shared cathode pad into multiple voltage zones with different reference voltages applied to different regions, allowing independent voltage control for different LED groups while maintaining the physical simplicity of a shared pad structure

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies different reference voltages to different local regions of the cathode pads based on the specific electrical requirements of connected LEDs, optimizing current distribution and brightness uniformity across the display

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 compact, high-resolution display with improved brightness, energy efficiency, and longer lifespan by eliminating the need for backlights and liquid crystals, while ensuring reliable operation through the use of inorganic LEDs and a robust connection method.

Implementation Method 1

connected through anisotropic conductive films

Methodology Applied
Scientific EffectAnisotropic conduction: Anisotropy

Implementation Method 2

utilizing inorganic micro LEDs with optimized arrangements of LEDs and electrode pads

Methodology Applied
Scientific EffectLight emission from LED: Light Emitting Diode

Implementation Method 3

self-luminous display in which each pixel emits light by itself and includes, for example, a light-emitting diode (LED)

Methodology Applied
Scientific EffectElectroluminescence: Electroluminescence

Data Source

PatentEP3772752B1Display apparatus and manufacturing method thereof
Publication Date: 2023.08.30 SAMSUNG ELECTRONICS CO LTD
  • EP3772752B1 patent drawingFigure 1
  • EP3772752B1 patent drawingFigure 2
  • EP3772752B1 patent drawingFigure 3

AI summary

A display apparatus is provided. The display apparatus includes a plurality of anode pads disposed on a substrate and spaced apart from each other along a first direction; a cathode pad disposed on the substrate and spaced apart from the plurality of anode pads along a second direction that crosses the first direction; a plurality of repair anode pads disposed on the substrate, spaced apart from each other along the first direction, and spaced apart from the plurality of anode pads and the cathode pad along the second direction; and a plurality of light emitting diodes (LEDs) disposed on the substrate and spaced apart from each other along the first direction, each of the plurality of LEDs including an anode that is electrically connected to a corresponding anode pad from among the plurality of anode pads and a cathode that is electrically connected to the cathode pad.