Hybrid Touch Panel Driving Circuit Using Single Sensing Path

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Solution Overview

Problem

Conventional touch panel driving circuits require separate sensing circuits for mutual capacitance and self capacitance sensing modes, leading to increased size and complexity, and are unable to accurately detect touch coordinates on large touch panels.

Innovation Solution

A driving circuit that selectively operates in either mutual capacitance or self capacitance sensing mode using a single sensing circuit, featuring a mode selection unit and a conversion unit to sense and convert capacitance changes, with a first path unit for mutual capacitance sensing and a second path unit for self capacitance sensing, including a variable capacitor to cancel electrode capacitance for enhanced sensitivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If separate sensing circuits are used for mutual capacitance sensing mode and self capacitance sensing mode, then the touch panel can support both sensing modes, but the size and complexity of the driving circuit increases

Engineering Contradiction:

Improvesensing mode compatibilityVSAvoiddriving circuit complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The sensing circuit is designed to perform both mutual capacitance sensing and self capacitance sensing functions using the same hardware components. The mode selection operating unit switches between different sensing modes, allowing a single sensing circuit to serve multiple purposes that would traditionally require separate dedicated circuits for each mode.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The sensing circuit incorporates dynamic switching capability through the mode selection operating unit, which can selectively activate different sensing pathways based on the required mode. This dynamic reconfiguration allows the circuit to adapt its behavior and measurement approach depending on whether mutual or self capacitance sensing is needed, rather than requiring static separate circuits for each mode.

Inventive Principle:

Principle #15Dynamics

2Adaptability or versatility

If separate sensing circuits are used for mutual capacitance sensing mode and self capacitance sensing mode, then the touch panel can support both sensing modes, but the size of the driving circuit increases

Engineering Contradiction:

Improvesensing mode compatibilityVSAvoiddriving circuit area

Core Design Contradiction:

Adaptability or versatilityVSArea of stationary object

Solution Approach 1:

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges the previously separate mutual capacitance sensing circuit and self capacitance sensing circuit into a single integrated sensing circuit. By combining the sensing pathways and sharing common components such as capacitors, switches, and signal processing elements, the overall circuit area is reduced while maintaining support for both sensing modes through selective operation.

Inventive Principle:

Principle #5Merging (Combining)

3Measurement precision

If conventional driving circuit is used, then the circuit structure is simple, but the touch coordinates cannot be accurately detected on large touch panels

Engineering Contradiction:

Improvetouch coordinate detection accuracyVSAvoidcircuit structure complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent employs parameter changes by introducing variable capacitors that can be adjusted to compensate for variations in electrode capacitance across different touch panel sizes. By dynamically adjusting capacitor values and switching between different sensing modes, the circuit maintains high measurement precision for touch coordinate detection whether the panel is small or large, without requiring a completely different circuit architecture.

Inventive Principle:

Principle #35Parameter changes

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 the size and complexity of the driving circuit while enabling efficient touch coordinate detection in both small and large touch panels, allowing for selective use of sensing modes based on user needs and improving touch sensitivity.

Implementation Method 1

a first path unit including a capacitor having capacitance changed in response to touch of the touch panel

Methodology Applied

Scientific EffectCapacitance: Capacitance

Implementation Method 2

a second path unit including a variable capacitor... the variable capacitor to cancel electrode capacitance for enhanced sensitivity

Methodology Applied

Scientific EffectCapacitance cancellation: Capacitance

Data Source

PatentUS10627954B2Driving circuit for a touch panel realizing modes using a sensing circuit and touch sensing method using the same

Publication Date: 2020.04.21 INDUSTRY UNIVERSITY COOPERATION FOUNDATION HANYANG UNIVERSITY

AI summary

A driving circuit for a touch panel is disclosed. The driving circuit switches between a mutual capacitance sensing mode and a self capacitance sensing mode using the same sensing circuit. As such, the driving circuit for a touch panel implements a hybrid touch panel that is capable of sensing a touch in either a mutual capacitance sensing mode or a self capacitance sensing mode without requiring a complex and large driving circuit for separate sensing circuits for each mode.