AR/VR Stylus Capacitive Button Layout to Reduce Side Interference

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Solution Overview

Problem

Existing AR/VR stylus devices face challenges with capacitive button detection due to the form factor, leading to false button press detections when the user's finger rests on the stylus housing near the buttons, and there is a need for an improved button design that minimizes side interference.

Innovation Solution

A capacitive button design with a conductive element, such as a pogo pin, extending from the capacitive sensing electrode into the button, positioned closer to the top surface than the side of the curved housing, along with a self-adjusting length to accommodate button depression, reducing false detections.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If capacitive detection buttons are used on a curved housing with a slim stylus form factor, then the stylus can maintain a sleek and ergonomic design, but the capacitive sensing electrode becomes closer to the stylus side than the button top, causing side interference and false touch events

Engineering Contradiction:

Improvestylus form factorVSAvoidbutton press detection accuracy

Core Design Contradiction:

ShapeVSMeasurement precision

Solution Approach 1:

The conductive element is positioned asymmetrically within the button structure, placing it closer to the top surface than to the curved housing sides. This creates a localized capacitive sensing zone that is spatially differentiated from side surfaces, allowing the electrode to distinguish between intentional button presses and incidental contact with the stylus body.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The solution transitions from a two-dimensional capacitive sensing plane to a three-dimensional structured approach by extending the conductive element vertically into the button. This dimensional adjustment creates distinct capacitive coupling paths: a short path to the button top surface and a longer path to the curved housing sides, enabling the system to differentiate touch locations based on coupling strength.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Ease of manufacture

If the capacitive sensing electrode is positioned closer to the curved housing to accommodate the slim stylus design, then manufacturing is simplified, but side interference causes incorrect touch event reports

Engineering Contradiction:

Improveelectrode positioningVSAvoidtouch sensor accuracy

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The conductive element acts as an intermediary between the capacitive sensing electrode and the button top surface. It extends the electrode's sensing capability toward the button top while maintaining the electrode's physical position closer to the curved housing for manufacturing simplicity. This intermediary structure creates a controlled capacitive coupling that prioritizes sensitivity to button presses over side contact.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Device complexity

If a traditional button design is used without a conductive element extension, then the button structure is simpler, but false button press detections occur when the user's finger rests on the stylus housing near the buttons

Engineering Contradiction:

Improvebutton structureVSAvoidfalse detection

Core Design Contradiction:

Device complexityVSObject-affected harmful factors

Solution Approach 1:

The conductive element creates a localized capacitive sensing region concentrated at the button top surface. This localized quality ensures that capacitive coupling is strongest when a finger contacts the button top, while coupling to side surfaces remains weak. The asymmetric positioning of the conductive element within the button structure provides spatial discrimination between valid button presses and false side contact.

Inventive Principle:

Principle #3Local quality

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

The design effectively minimizes false button press detections by ensuring the capacitive sensing is accurate, allowing for precise user input and extending battery life with a smaller capacitor requirement.

Implementation Method 1

capacitive sensing electrode is mounted below the button

Methodology Applied

Scientific EffectCapacitance: Capacitance

Implementation Method 2

A conductive element extends from the capacitive sensing electrode into the button

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 3

The conductive element has a self-adjusting length to accommodate depression of the button cap, such as a spring

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentUS12578803B2Capacitive sensing for an AR/VR stylus device

Publication Date: 2026.03.17 LOGITECH EUROPE SA

AI summary

A capacitive button for an input device with a curved housing is provided. A button cap extends through an opening in the curved housing. A capacitive sensing electrode is mounted below the button. A conductive element extends from the capacitive sensing electrode into the button. The conductive element is shaped such that it is closer to a top surface of the button than a side surface of the curved housing.