Force-Sensitive Touch Sensor Compensation for Contact Size Variations

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Solution Overview

Problem

Force-sensitive touch sensors in electronic devices often provide inaccurate force level measurements due to factors like contact size, environmental changes, and spatial effects, leading to inconsistent user experiences.

Innovation Solution

The implementation of force level calibration data that compensates for contact size and other factors, allowing for accurate force level assessments independent of touch size, and automatic gain control to adjust for environmental and electrical effects in real-time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If force-sensitive touch sensors are used to measure force level, then force measurement capability is provided, but measurement precision deteriorates due to contact size variations and environmental factors

Engineering Contradiction:
Improveforce level measurement accuracyVSAvoidcontact size effect, environmental changes, spatial effects
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent applies parameter changes by using force level calibration data that varies with user interaction size to compensate for contact area effects. The system changes the assessment parameters dynamically based on measured contact area, adjusting the force level calculation to maintain accuracy across different touch sizes and environmental conditions

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements feedback through automatic gain control that continuously monitors touch events and adjusts sensor sensitivity in real-time. The system uses measured force level data and contact area information to feedback-adjust the sensor gain, compensating for environmental changes and maintaining consistent measurement precision

Inventive Principle:
Principle #23Feedback

2Measurement precision

If compensation for contact size is implemented, then force level assessment accuracy is improved, but device complexity increases due to additional calibration data and processing

Engineering Contradiction:
Improveforce level assessment accuracyVSAvoidcalibration data structure, processing requirements
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by pre-calculating and storing force level calibration data for various user interaction sizes before actual use. The calibration data, including minimum and maximum touch event thresholds as functions of contact area, is prepared in advance to enable rapid compensation during touch events without complex real-time calculations

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent segments the force level assessment into distinct components: contact area measurement, calibration data selection based on contact size, and force level calculation. This segmentation allows the system to handle complexity in manageable steps, selecting appropriate calibration curves based on measured contact area ranges

Inventive Principle:
Principle #1Segmentation

3Reliability

If automatic gain control is implemented to adjust for environmental effects, then reliability of force measurement is improved, but device complexity increases

Engineering Contradiction:
Improveforce measurement consistencyVSAvoidgain control mechanism
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies self-service through automatic gain control that autonomously adjusts sensor sensitivity based on measured touch characteristics. The system automatically detects touch events, determines appropriate gain adjustments based on contact area and force level, and applies corrections without requiring manual calibration or external intervention, maintaining reliability through self-adjustment

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP3281092B1Force-sensitive touch sensor compensation
Publication Date: 2020.06.17 MICROSOFT TECHNOLOGY LICENSING LLC
  • EP3281092B1 patent drawingFigure 1
  • EP3281092B1 patent drawingFigure 2
  • EP3281092B1 patent drawingFigure 3~4

AI summary

An electronic device includes a memory in which input instructions, force level assessment instructions, and output instructions are stored, and further includes a processor coupled to the memory. The processor is configured through execution of the input instructions to obtain measurement data for a user interaction with a force-sensitive touch sensor, the measurement data being indicative of position information for the user interaction, amplitude information for the user interaction, and size information for the user interaction. The processor is further configured through execution of the force level assessment instructions to apply force level calibration data to the amplitude information and the size information in a force level assessment of the user interaction, the force level calibration data varying with user interaction size. The processor is further configured through execution of the output instructions to provide an output in accordance with the force level assessment.