Integrated LCD Touch Screen Common Electrode Merging

Solution Overview

Problem

Conventional LCDs with integrated touch screen panels require separate processes and adhesive layers, increasing processing time and cost, and may degrade image quality due to the attachment of touch screen panels on the outer surface.

Innovation Solution

An LCD with an integrated mutual capacitive touch screen panel where the common electrode serves as both a driving electrode and a touch screen panel electrode, utilizing a common electrode driver to supply driving signals and a gate driver to supply gate signals alternately, allowing the common electrode to be used for both image display and touch recognition without degrading image quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a touch screen panel is attached to an outer surface of a conventional flat panel display, then touch screen functionality is achieved, but processing time and costs increase due to separate processes and adhesive layers

Engineering Contradiction:

Improvetouch screen functionalityVSAvoidprocessing time

Core Design Contradiction:

Adaptability or versatilityVSProductivity

Solution Approach 1:

The patent merges the touch screen panel structure with the liquid crystal display structure by integrating the common electrode of the LCD as the driving electrode of the touch screen. This eliminates the need for separate touch screen panels and adhesive layers, thereby reducing processing time and costs while maintaining touch screen functionality

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The common electrode serves dual functions: as the common electrode for liquid crystal display operation and as the driving electrode for touch screen sensing. This multi-functionality eliminates redundant components and simplifies the overall structure, addressing both the need for touch functionality and the desire to reduce processing complexity

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If a touch screen panel is attached to an outer surface of a conventional flat panel display, then touch screen functionality is achieved, but costs increase due to separate processes and adhesive layers

Engineering Contradiction:

Improvetouch screen functionalityVSAvoidmanufacturing cost

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent merges the touch screen panel structure with the liquid crystal display structure by integrating the common electrode of the LCD as the driving electrode of the touch screen. This eliminates the need for separate touch screen panels and adhesive layers, thereby reducing processing time and costs while maintaining touch screen functionality

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The common electrode serves dual functions: as the common electrode for liquid crystal display operation and as the driving electrode for touch screen sensing. This multi-functionality eliminates redundant components and simplifies the overall structure, addressing both the need for touch functionality and the desire to reduce processing complexity

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Adaptability or versatility

If a touch screen panel is attached to an outer surface of a flat panel display, then touch screen functionality is achieved, but overall thickness of the flat panel display increases

Engineering Contradiction:

Improvetouch screen functionalityVSAvoidoverall thickness

Core Design Contradiction:

Adaptability or versatilityVSLength of stationary object

Solution Approach 1:

The patent merges the touch screen panel structure with the liquid crystal display structure by integrating the common electrode of the LCD as the driving electrode of the touch screen. This eliminates the need for separate touch screen panels and adhesive layers, thereby reducing processing time and costs while maintaining touch screen functionality

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The touch screen electrode structure is nested within the existing LCD structure, utilizing the common electrode as a shared component. This nesting approach allows the touch functionality to be embedded within the display structure without adding significant external thickness

Inventive Principle:

Principle #7Nested doll (Nesting)

4Productivity

If the common electrode is used as both driving electrode and touch screen electrode, then processing time and cost are reduced, but image quality may be degraded

Engineering Contradiction:

Improveprocessing efficiencyVSAvoidimage quality

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent segments the common electrode into multiple groups that can be independently controlled. By dividing the common electrode into groups and applying different voltages to different groups at different times, the system maintains image quality while enabling touch sensing functionality, thus resolving the conflict between processing efficiency and image quality

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent employs periodic switching of voltage signals to different groups of common electrodes. During certain time periods, driving signals are applied for image display, while during other periods, sensing signals are applied for touch detection. This periodic action allows the common electrode to serve both functions without compromising image quality

Inventive Principle:

Principle #19Periodic 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 solution reduces processing time and cost, decreases the thickness of the LCD, and enhances touch sensitivity without compromising image quality.

Implementation Method 1

a liquid crystal layer between the first and second substrates

Methodology Applied

Scientific EffectLiquid crystal phase change: Phase Change

Implementation Method 2

When a gate signal is applied to a gate line, a pixel electrode connected to the gate line and a common electrode receive a data signal and a common voltage, respectively, so that transmittance of light is controlled by an electric field

Methodology Applied

Scientific EffectElectric field effect on liquid crystal: Electric Field

Implementation Method 3

the capacitive touch screen panel converts a contact position into an electrical signal by sensing a change in capacitance formed between a conductive sensing pattern and an adjacent sensing pattern, ground electrode or the like

Methodology Applied

Scientific EffectCapacitance sensing: Capacitance

Data Source

PatentEP2447814B1Liquid crystal display with integrated touch screen panel and driving method thereof

Publication Date: 2016.04.13 SAMSUNG DISPLAY CO LTD

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AI summary

A liquid crystal display (LCD) with an integrated touch screen panel includes a plurality of pixels connected to a plurality of data lines and a plurality of gate lines, the gate lines being divided into a plurality of groups, a plurality of sensing electrodes, a plurality of common electrodes divided into a plurality of groups, a common electrode driver configured to simultaneously supply a driving signal to common electrodes within each group of the plurality of groups of the common electrodes, and to sequentially supply the driving signal to the plurality of groups of the common electrodes, and a gate driver configured to sequentially supply a gate signal to gate lines within each of the plurality of group of the gate lines.