Touch-Scanning Pulse Frequency Control for Power Efficiency

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Solution Overview

Problem

Portable electronic devices with touch-sensitive displays face challenges in power efficiency, as existing technologies do not effectively reduce power consumption while maintaining accurate touch detection, especially when in low-power conditions or during prolonged periods of inactivity.

Innovation Solution

The method involves applying a reduced number of pulses to scanning electrodes during low-power conditions to detect touches, while resuming full-pulse scanning when a touch is detected to ensure accuracy, thereby conserving power without compromising touch detection reliability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the number of pulses applied to scanning electrodes is reduced during low-power conditions, then power consumption is reduced, but touch detection accuracy may be compromised

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

Solution Approach 1:

The system dynamically adjusts the scanning pulse frequency based on detected touch states. During idle periods, the scanner operates at a reduced frequency to conserve power. When a touch is detected, the system automatically transitions to full scanning frequency to ensure accurate touch coordinate detection and prevent missed touches, thus resolving the contradiction between power savings and detection accuracy

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the operational parameters of the touch scanner by adjusting pulse frequency based on system state. The controller monitors touch detection status and modifies the scanning parameters accordingly - using lower pulse frequency for power saving during idle states, and switching to higher pulse frequency when touch detection is required, thereby balancing power consumption with detection reliability

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If full scanning is performed continuously, then touch detection accuracy is maintained, but power consumption increases

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

Solution Approach 1:

The system implements periodic scanning with variable intervals. Instead of continuous full-speed scanning, the controller performs scans at reduced frequency during idle periods, and increases scanning frequency only when touch events are detected. This periodic adaptation of scanning intensity maintains detection capability while significantly reducing overall power consumption

Inventive Principle:
Principle #19Periodic action

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 reduces power consumption by minimizing the number of pulses during low-power conditions while ensuring reliable touch detection, allowing the device to operate efficiently and accurately detect touches even with fewer pulses.

Implementation Method 1

a capacitive touchscreen system that is capable of sensing finger touches made on a capacitive touchscreen

Methodology Applied
Scientific EffectCapacitance: Capacitance

Data Source

PatentEP2660689B1Electronic device and method of detecting touches on a touch-sensitive display
Publication Date: 2019.12.25 BLACKBERRY LTD
  • EP2660689B1 patent drawingFigure 1
  • EP2660689B1 patent drawingFigure 2~5
  • EP2660689B1 patent drawingFigure 3

AI summary

A method includes applying a first plurality of pulses to scanning electrodes during a first scan to detect touches on a touch-sensitive display, receiving an indication to scan in a reduced power condition, and when in the reduced power condition, applying a second plurality of pulses to scanning electrodes during a second scan to detect touches on the touch-sensitive display, wherein the second plurality of pulses comprises fewer pulses than the first plurality of pulses.