Touch Driving Circuit Segmentation for Pen Sensing

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Solution Overview

Problem

Existing display apparatuses with touch panels often malfunction when a user's hand or palm touches the screen, causing interference with the touch pen's signal and disrupting pen sensing during touch drawing operations.

Innovation Solution

A display apparatus with a touch driving circuit that divides touch electrodes into groups and alternately supplies uplink signals to these groups during pen position sensing periods, minimizing signal attenuation from the user's hand or palm, allowing seamless pen touch sensing and tracking.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a touch panel is used to enable finger touch sensing, then user interface convenience is improved, but the user's hand or palm acts as a capacitor and resistor that attenuates the touch driving signal, causing touch pen malfunction

Engineering Contradiction:

Improvetouch interface convenienceVSAvoidtouch pen sensing accuracy

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The touch electrodes are divided into multiple touch groups, and the touch driving circuit alternately supplies uplink signals to different touch groups during pen position sensing periods. This segmentation allows the system to selectively activate specific electrode groups, reducing signal attenuation caused by the user's hand or palm acting as a capacitor and resistor.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The touch driving circuit operates in periodic cycles, alternating between supplying common voltage to all touch electrodes during display periods and supplying uplink signals to specific touch groups during pen position sensing periods. This periodic switching enables the system to maintain display functionality while periodically performing accurate pen position sensing with reduced signal attenuation.

Inventive Principle:

Principle #19Periodic action

2Duration of action of stationary object

If the touch driving circuit supplies common voltage to all touch electrodes during display periods, then image display is maintained, but signal attenuation occurs when user's hand or palm touches the display panel

Engineering Contradiction:

Improvedisplay continuityVSAvoidsignal attenuation

Core Design Contradiction:

Duration of action of stationary objectVSLoss of energy

Solution Approach 1:

The touch electrodes are segmented into multiple touch groups that can be independently controlled. During pen position sensing periods, the circuit selectively supplies uplink signals only to the relevant touch groups rather than all touch electrodes, reducing signal attenuation while maintaining display continuity through alternating operation modes.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The touch driving circuit dynamically switches between two operating modes: supplying common voltage to all touch electrodes during display periods to maintain image display, and supplying uplink signals to specific touch groups during pen position sensing periods to reduce signal attenuation and improve sensing accuracy.

Inventive Principle:

Principle #15Dynamics

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

Enables reliable pen touch sensing and continuous touch drawing even when the user's hand or palm is in contact with the display panel, reducing signal attenuation and improving user experience.

Implementation Method 1

The touch driving circuit supplies a common voltage to the plurality of touch electrodes at each of a plurality of display periods, during which an image is displayed on the display panel

Methodology Applied

Scientific EffectCommon voltage supply:

Implementation Method 2

senses a position of a touch pen at each of a plurality of pen position sensing period

Methodology Applied

Scientific EffectCapacitive sensing: Capacitance

Implementation Method 3

the user's body may act as a capacitor and a resistor attenuating a touch driving signal transmitted from the display panel to the touch pen

Methodology Applied

Scientific EffectSignal attenuation: Electrical Resistance

Data Source

PatentUS11175766B2Display apparatus

Publication Date: 2021.11.16 LG DISPLAY CO LTD

AI summary

Disclosed is a display apparatus capable of sensing a pen touch without malfunction even when a user's hand or palm touches the display apparatus. The display apparatus includes a touch driving circuit dividing a plurality of touch electrodes arranged in a display panel into a plurality of touch groups, supplying a common voltage to the plurality of touch electrodes at each of a plurality of display periods, and sensing a position of a touch pen through some of the plurality of touch electrodes at each of a plurality of pen sensing periods, wherein the touch driving circuit supplies an uplink signal to some of the plurality of touch groups at each of at least one pen position sensing period among the plurality of pen sensing periods and senses a downlink signal transmitted from the touch pen through the touch groups to which the uplink signal has been supplied to generate pen touch raw data.