Button Force Sensing and Haptic Output via Electromagnetic Engine

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Solution Overview

Problem

Existing buttons in electronic devices lack effective force sensing and haptic output capabilities, particularly in context-sensitive applications where varied inputs are required based on active contexts, such as volume control on smartphones or tablets.

Innovation Solution

Integration of a permanent magnet biased electromagnetic haptic engine with a force sensor that constrains the movement of a rotor or shuttle to provide haptic outputs and sense applied forces, allowing for customizable haptic responses based on detected forces and device contexts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a button is designed with basic mechanical switch functionality, then it provides simple input capability, but it lacks force sensing and haptic output capabilities

Engineering Contradiction:

Improveforce sensing and haptic output capabilitiesVSAvoidbutton structure complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent combines multiple functions (mechanical switch, force sensor, and haptic engine) into a single integrated button assembly. The button includes a mechanical switch for basic input, a force sensor for detecting applied force magnitude, and a haptic engine for providing tactile feedback, all within one unified structure that can be mounted on a device sidewall.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The button is designed as a multi-functional component that can perform various operations depending on the active context. It detects different input types (press direction, force magnitude) and can trigger different actions (volume up/down, media playback, app switching) based on the detected input characteristics and device state, making it adaptable to multiple use scenarios.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If a button provides context-sensitive input capabilities with multiple detection modes, then it enhances user interaction flexibility, but it increases the complexity of force sensing and haptic control

Engineering Contradiction:

Improvecontext-sensitive input capabilitiesVSAvoidsensing and control system complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The button system dynamically adapts its behavior based on the active context or application state. The same physical button can trigger different functions (e.g., volume control in audio mode, media playback in video mode, or app switching in navigation mode) depending on what application is currently active, providing context-sensitive operation without requiring multiple physical buttons.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The haptic engine provides tactile feedback to confirm button presses and indicate different operational states. The force sensor continuously monitors applied force and provides feedback signals to the control system, which adjusts the button response and haptic output accordingly, creating a closed-loop control system that adapts to user input in real-time.

Inventive Principle:

Principle #23Feedback

3Force

If a haptic engine is designed with high force density, then it provides strong haptic feedback, but it increases power consumption

Engineering Contradiction:

Improvehaptic engine force densityVSAvoidpower consumption

Core Design Contradiction:

ForceVSUse of energy by moving object

Solution Approach 1:

The haptic engine operates in periodic pulses rather than continuously, activating only when a button press is detected and deactivating between presses. This pulsed operation mode allows the engine to deliver strong haptic feedback when needed while minimizing power consumption during idle periods, resolving the contradiction between force density and energy usage.

Inventive Principle:

Principle #19Periodic action

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 solution enables buttons to provide precise force sensing and haptic feedback, enhancing user interaction by allowing for context-dependent inputs and improved haptic experiences with high engine force density and low power consumption.

Implementation Method 1

The haptic engine may be a permanent magnet biased electromagnetic haptic engine (or a permanent magnet biased normal flux electromagnetic haptic engine)

Methodology Applied

Scientific EffectElectromagnetic force: Lorentz Force

Implementation Method 2

A force sensor may be at least partially attached to the permanent magnet biased electromagnetic haptic engine, and may be configured to sense a force applied to the rotor

Methodology Applied

Scientific EffectForce sensing: Piezoresistive Effect

Data Source

PatentUS10691211B2Button providing force sensing and/or haptic output

Publication Date: 2020.06.23 APPLE INC

AI summary

A module includes a permanent magnet biased electromagnetic haptic engine having a stator and a rotor; a constraint coupled to the stator and the rotor; and a force sensor at least partially attached to the permanent magnet biased electromagnetic haptic engine and configured to sense a force applied to the rotor. The constraint is configured to constrain closure of a gap between the rotor and the stator and bias the rotor toward a rest position in which the rotor is separated from the stator by the gap.