Dual Electrode Touch Detection for Power Management

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Solution Overview

Problem

Portable electronic devices with touch-sensitive displays face challenges in power management, particularly in reducing noise and optimizing touch detection while conserving energy, especially when operating in reduced power conditions.

Innovation Solution

The implementation of a dual electrode system where display electrodes are used for normal power conditions to detect touches and on-cell drive electrodes are used in reduced power conditions, with sense electrodes coupled to a touch controller to facilitate touch detection without powering the display controller, thereby reducing power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the display controller is used to drive display electrodes for touch detection, then touch detection accuracy is improved, but power consumption increases

Engineering Contradiction:
Improvetouch detection accuracyVSAvoidpower consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent segments the touch detection function into two distinct pathways: one using display electrodes driven by the display controller for high-accuracy detection, and another using separate sense electrodes driven by a dedicated touch controller for low-power operation. This segmentation allows the system to select the appropriate detection pathway based on power requirements, resolving the contradiction between accuracy and power consumption.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements multi-functionality by enabling the touch-sensitive display to operate in two modes: using display electrodes for both display and touch detection functions, and using dedicated sense electrodes specifically for touch detection. This universal design allows the system to maintain touch detection capability across different power states without relying solely on the power-intensive display controller.

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

2Measurement precision

If noise reduction techniques are applied during touch detection, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improvenoise reductionVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts the noise reduction function into a separate processing stage handled by the touch controller, independent of the display controller. By separating the touch detection signal processing from the display control functions, the system can apply specialized noise reduction algorithms without complicating the display controller architecture, thus improving precision without proportionally increasing overall device complexity.

Inventive Principle:
Principle #2Taking out (Extraction)

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 efficient touch detection in both normal and reduced power conditions, conserving energy by minimizing the need to power the display controller during low-power operations and ensuring seamless transitions between power states, enhancing the usability and efficiency of portable electronic devices.

Implementation Method 1

A touch-sensitive display, also known as a touchscreen display, is particularly useful on handheld devices

Methodology Applied
Scientific EffectCapacitive touch sensing: Capacitance

Data Source

PatentEP2843506B1Electronic device including touch-sensitive display and method of detecting touches
Publication Date: 2017.11.08 BLACKBERRY LTD
  • EP2843506B1 patent drawingFigure 1
  • EP2843506B1 patent drawingFigure 2~3
  • EP2843506B1 patent drawingFigure 4~5

AI summary

An electronic device includes a display controller, first drive electrodes operably coupled to the display controller to drive the first drive electrodes to detect touches on a display while the electronic device is operating in a normal power condition, a touch controller operably coupled to the display controller, second drive electrodes operably coupled to the touch controller to drive the second drive electrodes to detect touches on the display while the electronic device is operating in a reduced power condition, and sense electrodes operably coupled to the touch controller.