Flexible OLED Touch Display Pad Integration

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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 in touch pads, due to separate glass substrates and complex manufacturing processes, which result in increased thickness and complexity.

Innovation Solution

The organic light emitting display integrates a touch electrode array inside a cover glass with a thin film transistor array and organic light emitting array formed on separate glass substrates, which are then joined and the glass substrates removed, using a laminate structure with interlayer insulating films and conductive balls to ensure effective signal transfer and reduced thickness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If separate glass substrates are used for organic light emitting display panel and touchscreen, then contact properties in touch pads are improved, but thickness and hardness increase

Engineering Contradiction:
Improvecontact propertiesVSAvoidthickness
Core Design Contradiction:
ReliabilityVSLength of stationary object

Solution Approach 1:

The patent merges the organic light emitting display panel and touchscreen into a single integrated structure where the touchscreen is formed directly on the cover glass of the display panel. The pad portions of both components are positioned to face each other internally, eliminating the need for separate glass substrates and external attachment, thus reducing thickness while maintaining contact properties through internal bonding.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent implements an in-cell type configuration where the touchscreen is nested within the cover glass structure of the organic light emitting display panel. The touch electrode array is formed inside the cover glass, and pad portions are positioned internally to face each other, creating a compact nested structure that reduces overall thickness while preserving electrical contact.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Reliability

If separate glass substrates are used for organic light emitting display panel and touchscreen, then contact properties in touch pads are improved, but device complexity increases

Engineering Contradiction:
Improvecontact propertiesVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the touchscreen and display panel manufacturing into a single integrated process. Both components are formed on the same cover glass substrate, eliminating the need for separate substrate handling, alignment, and bonding processes, thus reducing manufacturing complexity while maintaining reliable electrical contact through internal pad positioning.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If touchscreen is attached externally to organic light emitting display panel, then contact properties are improved, then manufacturing process complexity increases

Engineering Contradiction:
Improvecontact propertiesVSAvoidmanufacturing process simplicity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent performs preliminary action by forming the touchscreen electrode array and pad portions directly on the cover glass during the display panel manufacturing process, before final assembly. This preliminary integration eliminates subsequent external attachment steps, simplifying manufacturing while ensuring optimal contact properties through precise internal positioning of pad portions.

Inventive Principle:
Principle #10Preliminary action

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 a thin, flexible, and bendable display with improved touch sensitivity and reduced contact resistance, simplifying the manufacturing process and eliminating the need for additional touch screen attachment.

Implementation Method 1

a pad portion of the touch electrode array faces a pad portion of the organic light emitting array, and the pad portions are connected to each other via a conductive ball to allow for transfer of signals

Methodology Applied
Scientific EffectElectrical Conduction: Conduction (electrical)

Implementation Method 2

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

PatentEP2698821B1Organic light emitting display and method for manufacturing the same
Publication Date: 2018.08.08 LG DISPLAY CO LTD
  • EP2698821B1 patent drawingFigure 1
  • EP2698821B1 patent drawingFigure 2
  • EP2698821B1 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 in touch pads based on an improved structure, and a method for manufacturing the same, wherein a distance between the outermost surface of the touch pad portion and the outermost surface of the dummy pad portion in the touch pad portion is smaller than the distance in a neighboring portion adjacent to the touch pad portion.