OLED Touch Sensor Bridge Electrode Integration

Solution Overview

Problem

The challenge is to integrate a touch electrode and a color filter onto an organic light emitting diode display device while minimizing thickness and preventing color mixing between sub-pixels.

Innovation Solution

The solution involves a substrate with light emitting areas, a first encapsulation film covering light emitting elements, bridge electrodes between color filters, touch electrodes overlapping bridge electrodes, and a planarization film exposing touch electrodes, where the bridge electrode and touch electrode are on the same plane as the color filter, functioning as a black matrix to reduce thickness and prevent color mixing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the touch electrode and color filter are mounted on the light emitting element, then the display device can achieve touch functionality and color display, but the thickness of the display device increases

Engineering Contradiction:

Improvetouch functionalityVSAvoidthickness

Core Design Contradiction:

Adaptability or versatilityVSLength of stationary object

Solution Approach 1:

The bridge electrode and touch electrode are merged into a single conductive structure that serves both as a bridge connection and as a touch sensing element. This integration eliminates the need for separate touch electrode layers, thereby reducing overall device thickness while maintaining touch functionality.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The bridge electrode is designed to perform multiple functions: it serves as an electrical bridge connection between pixels and simultaneously functions as the touch electrode for capacitance-based touch sensing. This multi-functionality reduces the number of required layers and components, thereby reducing thickness.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If the touch electrode is positioned to overlap with the bridge electrode, then the touch sensitivity is improved, but color mixing between sub-pixels may occur

Engineering Contradiction:

Improvetouch sensitivityVSAvoidcolor mixing prevention

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The bridge electrode is designed with varying properties in different regions: in the overlap region with the touch electrode, it provides electrical connection and touch sensing functionality, while in other regions it maintains color isolation. This localized differentiation allows the same structure to serve multiple purposes without causing color mixing.

Inventive Principle:

Principle #3Local quality

3Adaptability or versatility

If multiple layers are added for touch electrode and color filter, then the display functionality is enhanced, but the device complexity increases

Engineering Contradiction:

Improvedisplay functionalityVSAvoidnumber of layers

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The bridge electrode and touch electrode are merged into a single conductive structure that serves both as a bridge connection and as a touch sensing element. This integration eliminates the need for separate touch electrode layers, thereby reducing overall device thickness while maintaining touch functionality.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The bridge electrode is designed to perform multiple functions: it serves as an electrical bridge connection between pixels and simultaneously functions as the touch electrode for capacitance-based touch sensing. This multi-functionality reduces the number of required layers and components, thereby reducing thickness.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 reduces the overall thickness of the display device and effectively prevents color mixing between sub-pixels by positioning the touch and bridge electrodes between light emitting areas, enhancing the display's performance.

Implementation Method 1

An organic light emitting element constituting the organic light emitting display is a self-luminous type

Methodology Applied

Scientific EffectElectroluminescence: Electroluminescence

Implementation Method 2

a plurality of color filters provided on the first encapsulation film to respectively correspond to the plurality of light emitting areas

Methodology Applied

Scientific EffectOptical filtering: Filter (optical)

Implementation Method 3

a capacitive touch sensing method, detecting the user's input by sensing a touch input on the basis of a change in capacitance formed in a touch electrode

Methodology Applied

Scientific EffectCapacitance sensing: Capacitance

Data Source

PatentUS11899863B2Organic light emitting diode display device including touch sensor and manufacturing method of same

Publication Date: 2024.02.13 LG DISPLAY CO LTD

AI summary

An organic light emitting diode display device including a touch sensor and a manufacturing method of the same are discussed. The display device includes a substrate having light emitting areas defined therein; light emitting elements provided on the light emitting areas on the substrate; a first encapsulation film covering the light emitting elements; color filters provided on the first encapsulation film to respectively correspond to the light emitting areas; bridge electrodes provided between the plurality of color filters on the first encapsulation film; a bank insulating film provided on the first encapsulation film to cover the bridge electrodes and surround the color filters; touch electrodes provided by being overlapped with the bridge electrodes on the bank insulating film; and a planarization film covering the color filters and the bank insulating film and exposing the touch electrodes.