Offset Contact-Zone Normalization for Touch Input Accuracy

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Solution Overview

Problem

Touch-sensitive input devices, such as touchscreens and virtual keyboards on mobile devices, often lack tactile feedback, leading to inaccuracies in data entry as the registered contact area may differ from the intended key selection, resulting in user frustration and errors.

Innovation Solution

Implementing a corrective-learning routine that identifies an offset contact-zone corresponding to each visible input key on the touch-sensitive keyboard, normalizing this zone to accurately register user inputs and account for variations in finger placement, thereby enhancing input accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a touch-sensitive keyboard is used without tactile feedback, then the device can be more compact and modern, but input accuracy deteriorates as the registered contact area differs from the intended key selection

Engineering Contradiction:
Improvedevice structureVSAvoidinput accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The system pre-calculates and stores offset values for each key based on historical input data and finger placement patterns. Before processing new input, the system retrieves these pre-computed offsets to adjust the contact zone registration, thereby compensating for the lack of tactile feedback and improving input accuracy without adding physical complexity

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system implements a feedback loop where each user input is analyzed to determine the actual contact point versus the intended key. This information is fed back to dynamically adjust the contact zone offset for future inputs, continuously improving accuracy. The system learns from user behavior patterns and adapts the registration area accordingly, resolving the contradiction between tactile absence and precision

Inventive Principle:
Principle #23Feedback

2Ease of operation

If the contact zone is centered on the visible key, then the interface appears intuitive, but miss-strikes increase due to variations in finger placement

Engineering Contradiction:
Improveinterface intuitivenessVSAvoidinput reliability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

Instead of using a uniform contact zone for all keys, the system applies localized offset adjustments to each individual key's contact zone based on empirical data about where users actually place their fingers. Each key has its own customized contact area that accounts for local variations in finger placement patterns, thereby maintaining visual intuitiveness while improving input reliability

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The system dynamically changes the parameters of the contact zone (position, size, shape) based on the specific key being targeted and historical usage data. By adjusting these parameters rather than using a fixed centered zone, the system compensates for finger placement variations and improves reliability while preserving the intuitive visual interface

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2101250B1Character selection on a device using offset contact-zone
Publication Date: 2014.06.11 BLACKBERRY LTD
  • EP2101250B1 patent drawingFigure 1
  • EP2101250B1 patent drawingFigure 2
  • EP2101250B1 patent drawingFigure 3A~3D

AI summary

A mobile device (300) having a housing (371) including a display screen (322) mounted therein as well as a touch-sensitive keyboard (640) and microprocessor (338) is disclosed. The microprocessor is communicatively connected between the display screen and the touch-sensitive keyboard. A program that runs on the microprocessor is also presented. The microprocessor-run program identifies an offset contact-zone (431) on the touch-sensitive keyboard that corresponds to a proximate visible input key (410). Additionally, the microprocessor-run program normalizes the identified offset contact-zone into registration with the corresponding proximate visible input key so that sensed contacts at the offset contact-zone actuate an input to the device associated with the corresponding visible input key.