Touch Driving Device Floating Display Electrode Parasitic Capacitance

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Solution Overview

Problem

The increasing parasitic capacitance between display electrodes and touch sensors in thinner panels disrupts the normal formation of downlink signals from active pens, leading to voltage issues and increased power consumption when trying to enhance driving voltage.

Innovation Solution

A touch driving device that transmits uplink signals and receives downlink signals by floating the display electrode during signal reception, using modulation signals with phases matching or differing by 180 degrees from the touch driving signal, to minimize parasitic capacitance effects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If the panel thickness is reduced, then the display device achieves thinner profile, but the parasitic capacitance between display electrode and touch sensor increases

Engineering Contradiction:

Improvepanel thicknessVSAvoidparasitic capacitance

Core Design Contradiction:

Length of moving objectVSObject-affected harmful factors

Solution Approach 1:

The patent applies the principle of converting harm into benefit by utilizing the parasitic capacitance between the display electrode and touch sensor, which was previously a harmful factor disrupting downlink signals, as a useful component for signal transmission. The system transmits uplink signals from the touch sensor to the active pen and downlink signals from the active pen to the touch sensor through this parasitic capacitance, thereby eliminating the need for separate signal lines and reducing overall system complexity.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The display electrode is designed to serve multiple functions: it acts as both a display electrode for showing images and as a signal transmission path for touch sensor communication. By floating the display electrode during downlink signal reception, the system enables the same electrode structure to facilitate both display operations and touch signal transmission without requiring additional dedicated electrodes or signal lines.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If the driving voltage of downlink signal is increased, then the signal strength is improved, but the power consumption increases

Engineering Contradiction:

Improvesignal strengthVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent applies parameter changes by dynamically adjusting the voltage level of the display electrode based on the operational phase. During downlink signal reception, the display electrode is floated to maintain a high voltage level that enhances signal strength. During other phases, the voltage is reduced to normal operating levels, thereby avoiding continuous high power consumption while maintaining reliable signal transmission when needed.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If the display electrode is floated during downlink signal reception, then the signal integrity is improved, but the device complexity increases

Engineering Contradiction:

Improvesignal integrityVSAvoidcontrol complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the control of the display electrode with the touch signal processing operations. The floating of the display electrode during downlink signal reception is integrated into the existing touch driver control logic, combining display electrode control with touch signal reception timing. This approach avoids requiring a completely separate control system while maintaining signal integrity.

Inventive Principle:

Principle #5Merging (Combining)

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

Improves the characteristics of downlink signals received from active pens by reducing the impact of parasitic capacitance, thereby maintaining signal integrity without increasing power consumption.

Implementation Method 1

a parasitic capacitance formed between the touch sensor and the display electrode

Methodology Applied

Scientific EffectParasitic capacitance: Parasitic Capacitance

Implementation Method 2

an active pen and a touch sensor are connected to each other through a mutual capacitance and through this mutual capacitance, a downlink signal may be transmitted or received

Methodology Applied

Scientific EffectMutual capacitance: Capacitance

Data Source

PatentUS10955963B2Touch driving device and display device

Publication Date: 2021.03.23 SILICON WORKS CO LTD

AI summary

The present disclosure provides a display device configured to float a display electrode coupled to a touch sensor by a parasitic capacitance when a downlink signal is received from a touch pen to the touch sensor.