Capacitive Touch Sensor Interface With Adaptive Serial Resistance

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Solution Overview

Problem

Capacitive touch sensors in household appliances are prone to cross-talk interference from environmental conditions like humidity and temperature, leading to reduced precision and functionality, as existing methods to mitigate this issue, such as grounding, result in loss of precision by diverting user input to the ground.

Innovation Solution

A capacitive sensor interface with electronically controllable serial resistance between the control unit and touch sensors, adjusted based on inputs from humidity, temperature, and electromagnetic interference sensors to dynamically optimize resistance values for improved performance under varying environmental conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If grounding surfaces are used to eliminate cross-talk between touch sensors, then cross-talk interference is reduced, but measurement precision deteriorates due to loss of user input signal to ground

Engineering Contradiction:
Improvecross-talk interferenceVSAvoidtouch sensor precision
Core Design Contradiction:
Object-affected harmful factorsVSMeasurement precision

Solution Approach 1:

The patent applies dynamics by making the resistance value adaptable and changeable based on environmental conditions. The resistance between the touch sensor and control unit is adjusted dynamically according to temperature and humidity levels, allowing the system to optimize its performance for different operating environments rather than using a fixed resistance value.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements parameter changes by modifying the resistance value in response to environmental parameter variations. Temperature and humidity sensors detect environmental changes, and the resistance is adjusted accordingly to compensate for the effects of these parameters on touch sensor operation, thereby maintaining measurement precision.

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If fixed resistance value is used in touch sensor circuit, then device complexity is reduced, but adaptability to environmental conditions deteriorates

Engineering Contradiction:
Improvecircuit complexityVSAvoidenvironmental adaptability
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent applies feedback by using temperature and humidity sensors to continuously monitor environmental conditions and adjusting the resistance value accordingly. This closed-loop feedback mechanism allows the system to automatically adapt to environmental changes without requiring complex manual calibration or multiple fixed resistance options.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system implements self-service by automatically adjusting its own resistance parameter based on environmental conditions detected by integrated sensors. The touch sensor circuit self-regulates its performance characteristics without external intervention, maintaining optimal operation across varying environmental conditions.

Inventive Principle:
Principle #25Self-service

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

Enhances the responsiveness and precision of capacitive touch sensors by minimizing cross-talk interference and adapting to environmental changes, ensuring reliable operation across different conditions without compromising signal resolution.

Implementation Method 1

a capacitive sensor interface with capacitive touch sensors (3) integrated to the control panel (10)

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 2

The control unit (5) is in electrical communication with at least one environmental parameter sensor selected from the group of a humidity sensor (6), a temperature sensor (7) and an electromagnetic interference sensor (8)

Methodology Applied
Scientific EffectTemperature sensing:

Data Source

PatentEP2979362B1Capacitive touch sensors interface implementation
Publication Date: 2019.05.08 ARCELIK AS
  • EP2979362B1 patent drawingFigure 1
  • EP2979362B1 patent drawingFigure 2

AI summary

The present invention relates to a household appliance (1) comprising a control panel (10) having a plurality of capacitive touch sensors (3). The capacitive touch sensors (3) are associated with operational functions to be performed by the household appliance (1). The household appliance (1) further comprises a control unit (5) in electrical communication with each of said plurality of capacitive touch sensors (3) through a conductive line (9). The conductive line (9) has a serial resistance (2) in between the control unit (5) and each of said plurality of capacitive touch sensors (3).