Capacitive Touch Panel Dynamic Mode Switching for Power and Accuracy

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Current capacitive touch panels face issues with high power consumption and inability to accurately detect multiple touch points, leading to errors and ghost points, especially with floating conductors and multi-touch applications.

Innovation Solution

A low power driving and sensing system that dynamically switches between self capacitance and mutual capacitance modes based on the number of touch points, using a control device to configure switch devices, driving, and sensing devices to optimize power usage and accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If self capacitance sensing mode is used, then power consumption is reduced and data processing is simplified, but multi-touch detection accuracy deteriorates and ghost points occur

Engineering Contradiction:

Improvepower consumptionVSAvoidmulti-touch detection accuracy

Core Design Contradiction:

Use of energy by moving objectVSMeasurement precision

Solution Approach 1:

The system dynamically switches between self capacitance sensing mode and mutual capacitance sensing mode based on the detected number of touch points. When single touch is detected, self capacitance mode is used for low power consumption; when multi-touch is detected, mutual capacitance mode is used for accurate multi-touch detection. This dynamic mode switching resolves the contradiction between power efficiency and measurement precision.

Inventive Principle:

Principle #15Dynamics

2Measurement precision

If mutual capacitance sensing mode is used, then multi-touch detection accuracy is improved, but power consumption increases and data processing complexity increases

Engineering Contradiction:

Improvemulti-touch detection accuracyVSAvoidpower consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The system uses mutual capacitance sensing mode only when multi-touch is detected, switching back to self capacitance mode for single touch scenarios. This dynamic adaptation ensures high measurement precision when needed while minimizing power consumption during normal single-touch operation.

Inventive Principle:

Principle #15Dynamics

3Device complexity

If self capacitance sensing is used, then hardware cost is reduced and sensing speed is improved, but reliability deteriorates due to erroneous touch point decisions

Engineering Contradiction:

Improvehardware complexityVSAvoidtouch point detection reliability

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The system maintains simple hardware architecture using self capacitance sensing but dynamically switches to mutual capacitance sensing mode when multi-touch is detected to ensure reliable and accurate touch point detection. This resolves the reliability issue without increasing hardware complexity.

Inventive Principle:

Principle #15Dynamics

4Productivity

If self capacitance sensing is used, then sensing speed is improved, but reliability worsens due to ghost points and erroneous decisions

Engineering Contradiction:

Improvesensing speedVSAvoidtouch point detection reliability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The system operates in fast self capacitance sensing mode for single touch to maintain high sensing speed, but switches to mutual capacitance sensing mode when multi-touch is detected to eliminate ghost points and ensure reliable detection. This dynamic switching maintains productivity while improving reliability when needed.

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

Reduces power consumption while enabling accurate multi-touch detection by adapting sensing modes, thereby prolonging handheld device battery life and improving user interaction.

Implementation Method 1

A capacitive touch panel uses the current or the voltage originated from capacitance changes in a static electricity combination of transparent electrodes in row and column with human body to detect the touching coordinate.

Methodology Applied

Scientific EffectCapacitance: Capacitance

Implementation Method 2

Instead of being a physical capacitor, the self capacitance or the grounded capacitance is parasitic and stray capacitance on each conductor line.

Methodology Applied

Scientific EffectParasitic capacitance: Parasitic Capacitance

Data Source

PatentUS8970527B2Capacitive touch panel having mutual capacitance and self capacitance sensing modes and sensing method thereof

Publication Date: 2015.03.03 ORISE TECH CO LTD

AI summary

A low power driving and sensing system for capacitive touch panels includes a capacitive touch panel, a first switch device, a second switch device, a driving device, a sensing device, and a control device. The capacitive touch panel has plural first conductor lines arranged in a first direction and plural second conductor lines arranged in a second direction. The driving device is connected to the first switch device for driving the capacitive touch panel. The sensing device is connected to the second switch device for sensing the capacitive touch panel. The control device configures the first switch device and the second switch device for entering the capacitive touch panel into a self-capacitance mode such that the driving device and the sensing device perform a self capacitance sensing, and into a mutual capacitance mode such that the driving device and the sensing device perform a mutual capacitance sensing.