Touch Display Common Electrode Voltage Synchronization

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Solution Overview

Problem

Touch display devices face challenges in simultaneously performing display driving and touch sensing without compromising image quality or touch sensitivity, particularly due to time division driving methods that require precise timing control and expensive components, leading to deteriorated image quality and touch sensitivity.

Innovation Solution

A touch display device and driving method that utilize a display panel with data lines, gate lines, and common electrodes, where a common voltage alternates between two levels synchronized with data voltage changes, allowing for simultaneous display driving and touch sensing while minimizing the impact of voltage state changes on touch sensitivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If time division driving method is used to separate display driving and touch driving, then display function and touch sensing function can be provided, but precise timing control is required and expensive components are needed

Engineering Contradiction:

Improvedisplay function and touch sensing functionVSAvoidtiming control and components

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent merges display driving and touch sensing driving into a single integrated driving circuit that operates simultaneously. The driving circuit generates both data voltages for display and common voltages for touch sensing without requiring separate control systems, thereby reducing device complexity while maintaining dual functionality.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The common electrode serves dual purposes: it acts as a display electrode for image rendering and simultaneously functions as a touch sensing electrode for detecting touch input. This multi-functionality eliminates the need for separate timing control mechanisms and reduces component requirements.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If time division driving method is used to separate display driving and touch driving, then display function and touch sensing function can be provided, but both display driving time and touch driving time may be insufficient

Engineering Contradiction:

Improvedisplay function and touch sensing functionVSAvoiddisplay driving time and touch driving time

Core Design Contradiction:

Adaptability or versatilityVSProductivity

Solution Approach 1:

The patent enables continuous simultaneous operation of display driving and touch sensing driving. By eliminating the time division approach, both functions operate continuously without interruption, ensuring sufficient driving time for both display refresh and touch sensing acquisition.

Inventive Principle:

Principle #20Continuity of useful action

3Measurement precision

If common voltage changes are synchronized with data voltage changes, then touch sensitivity can be maintained, but display touch crosstalk may occur due to voltage state changes

Engineering Contradiction:

Improvetouch sensitivityVSAvoiddisplay touch crosstalk

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a delay between data voltage changes and common voltage changes. The common voltage changes occur after a predetermined time following data voltage changes, which prevents simultaneous voltage transitions that would cause display touch crosstalk while maintaining touch sensitivity through subsequent synchronization.

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

The solution enables simultaneous display driving and touch sensing without deteriorating touch sensitivity, preventing display touch crosstalk and signal distortion, even during specific display patterns, thereby improving overall performance and reliability.

Implementation Method 1

a plurality of common electrodes COM; a first circuit configured to supply a data voltage to the plurality of data lines, supply a common voltage that alternates between a first common voltage level and a second common voltage level that is greater than the first common voltage level to the plurality of common electrodes, and detect a signal from at least one of the plurality of common electrodes

Methodology Applied

Scientific EffectCapacitance: Capacitance

Data Source

PatentUS11797096B2Touch display device, driving method, and driving circuit

Publication Date: 2023.10.24 LG DISPLAY CO LTD

AI summary

Embodiments of the present disclosure relate to a touch display device, a driving method, and a driving circuit. More particularly, embodiments of the present disclosure relate to a touch display device, a driving method, and a driving circuit capable of preventing touch sensitivity from being affected by display driving even though simultaneously performing the display driving and touch driving by supplying a data voltage to a plurality of data lines disposed in a display panel, supplying a common voltage to a plurality of common electrodes disposed in the display panel, displaying an image through the display panel, and supplying a common voltage to the common electrodes.