Touchscreen Electrode Switching for Low-Power Gesture Detection

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Solution Overview

Problem

Existing touch-sensitive displays in portable electronic devices face challenges in efficiently detecting touches and gestures while conserving power, especially when the device is in a low-power mode or locked state, due to limitations in current mutual-capacitance and self-capacitance touch sensing technologies.

Innovation Solution

The implementation of a touch-sensitive display system that utilizes first electrodes for mutual-capacitance touch sensing and second electrodes for self-capacitance touch sensing, with additional electrodes disposed between sense electrodes to enhance touch location detection and gesture recognition, allowing for power conservation by switching between mutual-capacitance and self-capacitance sensing modes based on device activity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If mutual-capacitance touch sensing is used for accurate touch detection, then touch location precision is improved, but power consumption increases

Engineering Contradiction:
Improvetouch location precisionVSAvoidpower consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent implements dynamic switching between mutual-capacitance and self-capacitance sensing modes based on device state. In active states, mutual-capacitance provides high precision touch location detection. In low-power states, the system switches to self-capacitance mode which consumes less power while still providing sufficient touch detection capability. This dynamic adaptation resolves the contradiction by adjusting the sensing mode according to operational requirements.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the operational parameters of the touch sensor by switching between two distinct sensing modes (mutual-capacitance and self-capacitance). Each mode has different power consumption characteristics and precision levels. By changing the sensing parameter based on device state, the system optimizes the balance between precision and power consumption.

Inventive Principle:
Principle #35Parameter changes

2Use of energy by moving object

If self-capacitance touch sensing is used to conserve power, then power consumption is reduced, but touch detection accuracy deteriorates

Engineering Contradiction:
Improvepower consumptionVSAvoidtouch detection accuracy
Core Design Contradiction:
Use of energy by moving objectVSMeasurement precision

Solution Approach 1:

The system dynamically selects the appropriate sensing mode based on device state. When power conservation is needed (low-power mode or locked state), self-capacitance sensing is activated which consumes less power. When full functionality is required, the system switches to mutual-capacitance mode for accurate touch detection. This dynamic selection resolves the contradiction by matching the sensing mode to the operational context.

Inventive Principle:
Principle #15Dynamics

3Adaptability or versatility

If additional electrodes are added between sense electrodes to enhance gesture recognition, then gesture detection capability is improved, but device complexity increases

Engineering Contradiction:
Improvegesture detection capabilityVSAvoidelectrode structure complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The additional electrodes between sense electrodes serve multiple functions: they provide extra sensing points for improved gesture recognition, enhance touch location detection precision, and work with both mutual-capacitance and self-capacitance sensing modes. This multi-functionality justifies the increased complexity by providing enhanced capabilities across different operational modes.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The additional electrodes add a new dimension to the electrode structure by placing sensing elements between the traditional sense electrodes. This creates a more dense sensing grid that improves gesture detection capability and touch location precision without fundamentally changing the basic electrode architecture.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 approach enables accurate detection of touches and gestures even in low-power conditions, reducing power consumption by utilizing self-capacitance touch sensing when the display is off, and improving touch location and gesture detection precision through the use of additional electrodes.

Implementation Method 1

The display includes a touch-sensitive display, also referred to as a touchscreen display

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 2

detecting touches by mutual-capacitance touch sensing utilizing first electrodes and second electrodes

Methodology Applied
Scientific EffectMutual capacitance: Capacitance

Implementation Method 3

detecting touches by self-capacitance touch sensing utilizing the second electrodes and third electrodes

Methodology Applied
Scientific EffectSelf capacitance: Capacitance

Data Source

PatentEP3066547B1Electronic device including touch-sensitive display and method of detecting touches
Publication Date: 2022.01.05 BLACKBERRY LTD
  • EP3066547B1 patent drawingFigure 1
  • EP3066547B1 patent drawingFigure 2~4
  • EP3066547B1 patent drawingFigure 5

AI summary

A touch-sensitive display includes first electrodes and second electrodes coupled to a first controller to detect touches by self-capacitance touch sensing. The touch-sensitive display also includes third electrodes coupled to a second controller to detect touches by mutual-capacitance touch sensing utilizing the third electrodes and the second electrodes. The first electrodes are different from the third electrodes.