Touch Key Sensitivity Control for Mobile Input Error Prevention

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Solution Overview

Problem

Mobile communications terminals with touch-type keypads face issues of unintended key inputs due to narrow key intervals, leading to input errors and complicating miniaturization, as they require precise force application and risk accidental activation of nearby keys.

Innovation Solution

A method and system for a mobile communications terminal that uses a touch sensor unit with capacitance sensing to detect key inputs and a controller to adjust sensitivity levels and time thresholds for each key, prioritizing key inputs based on task relevance and distinguishing between intended and unintended key presses by analyzing capacitance signals and contact times.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If keys are arranged at narrow intervals to enable miniaturization, then device size is reduced, but key input accuracy deteriorates due to accidental activation of nearby keys

Engineering Contradiction:
Improvedevice sizeVSAvoidkey input accuracy
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

The patent applies different sensitivity levels to different keys based on their spatial relationships. Keys that are closer together are assigned different sensitivity thresholds, with the closer key having lower sensitivity to prevent accidental activation. This local differentiation of sensitivity parameters allows narrow key spacing while maintaining input accuracy.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The system dynamically adjusts sensitivity parameters (time thresholds and capacitance thresholds) for each key based on detected touch patterns. When a potential accidental input is detected on a less relevant key, the system changes the sensitivity parameters to distinguish between intentional and unintentional touches, thereby maintaining reliability despite narrow key intervals.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If touch-type keypad is used to reduce force application on user's finger, then ease of operation is improved, but key input accuracy deteriorates due to unintended key activation

Engineering Contradiction:
Improveforce applicationVSAvoidkey input accuracy
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

Different keys are assigned different sensitivity levels based on their function and position. Keys that are more likely to be accidentally touched are given lower sensitivity thresholds, while keys that require intentional activation maintain higher thresholds. This local quality differentiation resolves the contradiction between ease of operation and input accuracy.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The system dynamically adjusts sensitivity parameters in real-time based on the detected touch pattern and the current task context. The sensitivity level is not fixed but adapts to distinguish between casual touches and intentional inputs, maintaining both ease of operation and reliability.

Inventive Principle:
Principle #15Dynamics

3Reliability

If sensitivity level is increased to prevent accidental key activation, then key input accuracy is improved, but ease of operation deteriorates due to requiring more precise force application

Engineering Contradiction:
Improvekey input accuracyVSAvoidforce application precision
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

Instead of uniformly increasing sensitivity across all keys, the system applies higher sensitivity only to specific keys where accidental activation is more likely. Other keys maintain lower sensitivity thresholds, preserving ease of operation while still preventing errors where needed.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The sensitivity level is dynamically adjusted based on the detected touch characteristics and task context. The system increases sensitivity temporarily only when accidental activation patterns are detected, rather than maintaining high sensitivity continuously, thus balancing reliability and ease of operation.

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

Effectively prevents key input errors by accurately identifying intended key inputs even at narrow key intervals, enhancing user convenience and enabling the miniaturization of mobile terminals by reducing accidental activations and improving task performance.

Implementation Method 1

a touch sensor unit which senses the key that is input by touching the keypad region

Methodology Applied
Scientific EffectCapacitance sensing: Capacitance

Data Source

PatentEP1986403B1Mobile communications terminal having key input error prevention function
Publication Date: 2011.07.13 LG ELECTRONICS INC
  • EP1986403B1 patent drawingFigure 1~2
  • EP1986403B1 patent drawingFigure 3
  • EP1986403B1 patent drawingFigure 4~5

AI summary

A mobile communications terminal and a method for preventing an input error of a key input unit are provided. The mobile communications terminal includes a touch sensor unit for sensing a key that is input by touching a keypad region in order to output a key input signal corresponding to the key and a controller adapted to determine a key input according to either a priority between multiple keys from which key signals are received or whether a received key signal was generated inadvertently.