Magnetic Touchpad Actuation for Consistent Haptic Feedback

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Solution Overview

Problem

Existing haptic feedback devices for touchpads, such as piezoelectric ceramic and linear motor devices, face issues with inconsistency, high cost, complexity, and size, making them unsuitable for slim-type electronic devices, while magnet and magnetic coil designs require expensive multi-layer circuit boards with unsatisfactory yield.

Innovation Solution

A touchpad design featuring a substrate, elastic bracket, and actuating device with spirally wound coils and magnetic elements, allowing for relative vibration and vibration feedback, utilizing a planar coil structure that reduces fabrication costs and allows for adjustable inductance and vibration amplitude, and includes a support element with positioning notches for efficient assembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If piezoelectric ceramic haptic feedback device is used, then vibration feedback can be provided, but assembly tolerance increases and pressure-vibration consistency deteriorates

Engineering Contradiction:

Improvevibration feedback consistencyVSAvoidassembly tolerance

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent replaces the piezoelectric ceramic element (mechanical/electrical system) with a magnetic actuation system consisting of a magnetic element and a magnetic coil. This substitution eliminates the assembly tolerance issues inherent in piezoelectric ceramic elements while maintaining the vibration feedback function through magnetic field interaction between the coil and magnet.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If linear motor haptic feedback device is used, then vibration feedback is achieved, but device complexity and fabrication cost increase

Engineering Contradiction:

Improvevibration feedbackVSAvoidinternal structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts only the essential vibration-generating function from the complex linear motor system, using a simplified magnetic element and magnetic coil arrangement. This extraction eliminates the need for the entire linear motor assembly while retaining the core vibration feedback capability, thereby reducing device complexity and fabrication cost.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent employs inexpensive magnetic elements and coils instead of costly linear motors. The magnetic actuation system uses readily available materials and simple construction methods, significantly reducing fabrication costs while achieving the same vibration feedback effect.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Reliability

If linear motor haptic feedback device is used, then vibration feedback is provided, but device thickness increases

Engineering Contradiction:

Improvevibration feedbackVSAvoiddevice thickness

Core Design Contradiction:

ReliabilityVSLength of moving object

Solution Approach 1:

The patent removes the thick linear motor assembly and replaces it with a thin magnetic actuation system consisting of a magnetic element and a magnetic coil. This extraction of the essential vibration function while eliminating unnecessary components results in significantly reduced device thickness, making it suitable for slim electronic devices.

Inventive Principle:

Principle #2Taking out (Extraction)

4Reliability

If multi-layer loop sensing wire is used, then inductance is increased, but manufacturing cost increases and yield decreases

Engineering Contradiction:

ImproveinductanceVSAvoidfabrication cost and yield

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent replaces the multi-layer circuit board loop structure with a simple magnetic coil assembly. Instead of etching complex multi-layer loops onto circuit boards, the invention uses a discrete magnetic coil that can be easily assembled, significantly simplifying manufacturing and improving yield while achieving the required inductance.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 provides cost-effective, intuitive vibration feedback with improved assembly efficiency and reduced thickness, suitable for slim-type electronic devices, overcoming the limitations of previous technologies.

Implementation Method 1

The first actuating member and the second actuating member are movable relative to each other in response to a magnetic field force

Methodology Applied

Scientific EffectMagnetic field force: Lorentz Force

Data Source

PatentUS12429991B2Touchpad

Publication Date: 2025.09.30 PRIMAX ELECTRONICS LTD

AI summary

A touchpad includes a substrate, an elastic bracket and an actuating device. The substrate has a first surface and a second surface. The elastic bracket is located beside the second surface of the substrate. The actuating device includes a first actuating member and a second actuating member. The first actuating member is located near the second surface of the substrate. The second actuating member is aligned with the first actuating member and fixed on a side of the elastic bracket facing the substrate. The first actuating member and the second actuating member are movable relative to each other in response to a magnetic field force. Consequently, a relative vibration between the substrate and the elastic bracket is generated. The first actuating member includes at least one first coil. Each of the at least one first coil is spirally wound to form a first hollow region.