Transparent Capacitive Knob Interface for Display-Area Sensing

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Solution Overview

Problem

Existing knob interfaces for electronic systems face limitations in functionality and feature configuration due to the use of larger inner diameters and smaller outer diameters, which restricts the space for capacitive coupling between knob hardware and touch pixels.

Innovation Solution

The implementation of a transparent conductive material layer in the knob interface, which electrically couples grid electrodes positioned below the knob interface to knob interface electrodes, allowing for additional sensing functions and improved signal-to-noise ratio.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If traditional donut shaped knob interface is used with larger inner diameter and smaller outer diameter, then the center area is free of opaque conductive material allowing display of information, but the space for capacitive coupling between knob hardware and touch pixels is limited

Engineering Contradiction:

Improvecenter area for displayVSAvoidfunctionality and feature configuration

Core Design Contradiction:

Area of stationary objectVSAdaptability or versatility

Solution Approach 1:

A transparent conductive material layer is introduced as an intermediary between the knob interface electrodes and the grid electrodes below. This transparent layer enables electrical coupling while allowing light to pass through the center area, thus maintaining display capability while expanding the capacitive coupling space to include inner diameter grid electrodes.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The knob interface employs a composite structure combining transparent conductive material with traditional conductive materials. The transparent conductive material layer is stacked over the fixed base, creating a multi-material system that simultaneously provides electrical conductivity and optical transparency, enabling both display and enhanced sensing functionality.

Inventive Principle:

Principle #40Composite materials

2Device complexity

If traditional knob interface without transparent conductive material is used, then the structure is simpler, but additional sensing functions and signal-to-noise ratio improvement are limited

Engineering Contradiction:

ImprovestructureVSAvoidsignal-to-noise ratio

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The transparent conductive material acts as a mediator that enables connection to additional grid electrodes positioned within the inner diameter area. This expands the effective sensing area and improves signal-to-noise ratio by incorporating more electrodes into the capacitive coupling without significantly increasing overall structural complexity.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Ease of manufacture

If grid electrodes within inner diameter are not electrically coupled, then the manufacturing is simpler, but the functionalities and features that can be configured for the knob interface are limited

Engineering Contradiction:

Improveelectrical coupling implementationVSAvoidfunctionalities and features

Core Design Contradiction:

Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The transparent conductive material layer serves multiple functions simultaneously: it provides electrical coupling for additional grid electrodes, maintains optical transparency for display, and enables various sensing functionalities including click, grab, and rotation detection. This multi-functionality is achieved through a single added layer, keeping manufacturing relatively simple while greatly expanding capabilities.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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

This solution enables the knob interface to include more functionalities such as click, grab, and additional sensing functions, while maintaining the ability to display information in the center area, thus enhancing the overall performance and feature set of the knob interface.

Implementation Method 1

capacitive coupling the knob hardware and the touch pixels

Methodology Applied

Scientific EffectCapacitive coupling: Capacitance

Data Source

PatentUS12326750B2Capacitive knob sensing system and method using transparent sensing

Publication Date: 2025.06.10 SYNAPTICS INC

AI summary

A system for using a transparent conductive material layer for a knob interface is provided. The system comprises: the knob interface comprising a fixed base and one or more knob interface electrodes; the transparent conductive material layer configured to electrically couple the subset of the plurality of grid electrodes to the one or more knob interface electrodes; and a processing system. The processing system is configured to: drive the plurality of grid electrodes with one or more signals; receive one or more resulting signals based on driving the plurality of grid electrodes with the one or more signals; and perform one or more actions based on the one or more resulting signals.