Capacitive Slider Sensor Layout for Accurate Finger Position Detection

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Solution Overview

Problem

Existing capacitive touch switches face challenges in accurately determining finger position due to close sensor element spacing, leading to signal interference and reduced precision in differentiation between sensor elements.

Innovation Solution

Arranging capacitive sensor elements in a continuous row with a specific angle (15° to 90°, preferably 45° to 80°) and overlap, ensuring they do not touch, with rectangular shapes having a long side and short side length difference, and using electrically conductive and elastic material for improved linearity and accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If sensor elements are arranged close to each other to increase density, then the quantity of sensor elements increases, but signal interference increases and measurement precision deteriorates

Engineering Contradiction:
Improvequantity of sensor elementsVSAvoidposition determination accuracy
Core Design Contradiction:
Quantity of substanceVSMeasurement precision

Solution Approach 1:

The sensor elements are arranged at an angle (15° to 90°) relative to the extension line, transforming the conventional linear arrangement into an angular/diagonal configuration. This dimensional change in arrangement allows sensor elements to be positioned closer together while maintaining adequate signal differentiation, as the angular offset creates distinct spatial relationships for signal detection and reduces interference between adjacent elements.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The sensor elements are designed with asymmetric rectangular shapes having different long and short sides, arranged at specific angles rather than symmetrically. This asymmetric configuration optimizes the detection zones and signal patterns, enabling better differentiation between closely spaced elements while maintaining high density, directly resolving the contradiction between quantity and measurement precision.

Inventive Principle:
Principle #4Asymmetry

2Measurement precision

If sensor elements are arranged at an angle to improve position accuracy, then measurement precision improves, but device complexity increases

Engineering Contradiction:
Improveposition determination accuracyVSAvoidsensor element arrangement complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent specifies a particular angular range (15° to 90°) for arranging sensor elements, transforming the arrangement from a simple linear configuration to an angular one. This parameter change optimizes the detection zones and signal patterns, enabling better differentiation between closely spaced elements while maintaining high density, directly resolving the contradiction between quantity and measurement precision.

Inventive Principle:
Principle #35Parameter changes

3Area of stationary object

If sensor elements are placed very close together to maximize density, then the area utilization improves, but signal swing decreases and differentiation precision deteriorates

Engineering Contradiction:
Improvearea utilizationVSAvoidsignal differentiation precision
Core Design Contradiction:
Area of stationary objectVSMeasurement precision

Solution Approach 1:

By arranging sensor elements at an angle rather than in a straight line, the patent creates additional spatial dimensionality in the detection pattern. This angular arrangement expands the effective detection area while maintaining close spacing, as the diagonal configuration creates distinct signal zones that prevent overlap and interference, thereby improving both area utilization and signal differentiation.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The asymmetric rectangular sensor elements with different long and short sides, arranged at specific angles, create optimized detection zones that maximize area coverage. The asymmetric configuration ensures that even when elements are closely spaced, their detection fields remain distinct, maintaining signal swing and differentiation precision while achieving high area utilization.

Inventive Principle:
Principle #4Asymmetry

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 position determination accuracy and signal differentiation by minimizing overlap and maintaining a precise distance between sensor elements, allowing for better capacitive touch switch performance.

Implementation Method 1

operating device has a control panel with capacitive sensor elements in order to form a capacitive touch or proximity switch

Methodology Applied
Scientific EffectCapacitance: Capacitance

Data Source

PatentEP2309647B1Operating device for an electric device
Publication Date: 2018.08.22 E G O ELEKTRO GERAETEBAU GMBH
  • EP2309647B1 patent drawingFigure 1~2
  • EP2309647B1 patent drawingFigure 3~4
  • EP2309647B1 patent drawing

AI summary

A control device (11) for an electrical device has a control panel, several capacitive sensor elements (15) for a capacitive touch or proximity switch being arranged under the control panel, which are arranged in a continuous row to form an elongate slider for operation by placing a finger and dragging over it. The sensor elements (15) are all of the same design with a rectangular shape, with the sensor elements (15) each having one of their first sides pointing towards one another and being arranged with all of their sides parallel to one another. Thus, they are oriented in the same way with respect to the continuous row, with the first sides rotated to the row along which the sensor elements (15) are arranged by an angle of between 15° and 65°.