Flexible OLED Touch Display with Conductive Ball Interconnects

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Solution Overview

Problem

Existing organic light emitting displays face challenges in achieving a thin film shape and flexibility while maintaining superior contact properties, as they require separate glass substrates and complex manufacturing processes, leading to increased thickness, hardness, and potential contact defects due to differences in panel shapes and bonding methods.

Innovation Solution

The solution involves forming a transistor-organic light emitting diode array and a touch electrode array on separate buffer layers with a touch pad portion and dummy pad portion, connected via conductive balls through first and second contact holes, allowing for a thin film and flexible display configuration with improved contact properties by distributing pressure and increasing contact areas.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If separate glass substrates are used for the display panel and touchscreen, then the structural strength and stability are improved, but the thickness and weight increase, and flexibility is reduced

Engineering Contradiction:
Improvestructural strengthVSAvoidthickness
Core Design Contradiction:
StrengthVSLength of moving object

Solution Approach 1:

The patent merges the display panel and touchscreen into a single integrated structure by forming both on the same substrate. The transistor-organic light emitting diode array and touch electrode array are fabricated on the same substrate with buffer layers, eliminating the need for separate glass substrates and reducing overall thickness while maintaining structural integrity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent employs thin film structures throughout, including buffer layers, transistor layers, organic light emitting diode layers, and touch electrode layers, all formed as thin films on the substrate. This enables the display to achieve flexibility and bendability while maintaining structural strength through the distributed thin film architecture.

Inventive Principle:
Principle #30Flexible shells and thin films

2Stability of the object's composition

If separate glass substrates are used for the display panel and touchscreen, then the structural stability is improved, but the manufacturing complexity increases

Engineering Contradiction:
Improvestructural stabilityVSAvoidmanufacturing complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent combines the manufacturing processes for the display panel and touchscreen into a single integrated fabrication sequence. Both the transistor-organic light emitting diode array and touch electrode array are formed on the same substrate using sequential thin film deposition and patterning steps, reducing the number of assembly operations and simplifying manufacturing.

Inventive Principle:
Principle #5Merging (Combining)

3Strength

If separate glass substrates are used for the display panel and touchscreen, then the structural integrity is improved, but the contact properties deteriorate due to panel shape differences

Engineering Contradiction:
Improvestructural integrityVSAvoidcontact properties
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

By integrating the display panel and touchscreen on the same substrate, the patent eliminates panel shape mismatches that occur when bonding separate panels. The touch electrode array and transistor-organic light emitting diode array are co-fabricated with aligned patterns, ensuring excellent contact properties and electrical connectivity without the defects associated with bonding separate panels of different shapes.

Inventive Principle:
Principle #5Merging (Combining)

4Strength

If separate glass substrates are used for the display panel and touchscreen, then the structural support is improved, but the weight increases

Engineering Contradiction:
Improvestructural supportVSAvoidweight
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The patent consolidates the display panel and touchscreen into a single structure on one substrate, eliminating the weight of the second separate glass substrate. The integrated design maintains structural support through the combined thin film layers and substrate, significantly reducing overall weight compared to the separate substrate approach.

Inventive Principle:
Principle #5Merging (Combining)

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

This configuration enables the realization of a thin, flexible, and bendable organic light emitting display with enhanced touch sensitivity and reduced manufacturing complexity, minimizing contact defects and increasing the yield and price competitiveness.

Implementation Method 1

When electric charges are injected into an organic film formed between an electron injection electrode (cathode) and a hole injection electrode (anode), electrons pair with holes and the pairs then decay. At this time, an organic light emitting diode emits light.

Methodology Applied
Scientific EffectElectroluminescence: Electroluminescence

Data Source

PatentEP2704197B1Organic light emitting display and method for manufacturing the same
Publication Date: 2018.04.18 LG DISPLAY CO LTD
  • EP2704197B1 patent drawingFigure 1
  • EP2704197B1 patent drawingFigure 2
  • EP2704197B1 patent drawingFigure 3

AI summary

Disclosed are an organic light emitting display that enables realization of a thin film shape and flexibility, and exhibits superior contact properties based on an improved structure, and a method for manufacturing the same, the organic light emitting display includes a plurality of touch pads spaced from one another in the touch pad portion, each of the touch pads including a metal pad layer and a transparent electrode pad layer connected to the metal pad layer via a plurality of first contact holes in a first insulating film, a dummy pad portion formed in the dead region of the first buffer layer, the dummy pad portion comprising a plurality of dummy pads corresponding to the touch pads, and a sealant comprising a plurality of conductive balls between the touch pad portion and the dummy pad portion.