Touchpad Haptic Control to Prevent Capacitive Sensing Errors

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Solution Overview

Problem

Vibration noise from the touchpad's vibration unit interferes with the capacitive sensing, leading to incorrect determination of touch object position and triggering of incorrect commands or gestures.

Innovation Solution

Implement a touch function restriction mode when the vibration unit is activated, limiting touch sensitivity to prevent erroneous capacitance sensing values.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the vibration unit is activated to provide haptic feedback, then user experience is improved, but vibration noise interferes with capacitive sensing causing incorrect touch position determination

Engineering Contradiction:

Improvehaptic feedbackVSAvoidtouch position determination

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The system enters a touch function restriction mode before the vibration unit is activated. This preliminary action prevents the vibration noise from interfering with capacitive sensing by restricting touch function execution during the vibration period, thereby avoiding incorrect touch position determination while maintaining haptic feedback capability

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The touch function restriction mode acts as a preliminary countermeasure against the harmful effect of vibration noise. By preemptively disabling touch function execution when vibration is detected or anticipated, the system neutralizes the interference between vibration noise and capacitive sensing signals before incorrect touch detection can occur

Inventive Principle:

Principle #9Preliminary anti-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

Prevents interference from vibration noise, ensuring accurate determination of touch information and reducing incorrect command triggers.

Implementation Method 1

the built-in vibration unit (such as a motor) is activated to produce vibration

Methodology Applied

Scientific EffectElectromagnetic actuation: Electromagnetic Induction

Implementation Method 2

a coupling capacitance is generated between the contact point of the touch object and the sensing electrodes located in relative positions on the touchpad. This coupling capacitance generates a capacitive sensing value, which is used to determine the position information of the contact point

Methodology Applied

Scientific EffectCapacitive sensing: Capacitance

Data Source

PatentUS12596455B2Control method for a touchpad

Publication Date: 2026.04.07 ELAN MICROELECTRONICS CORPORATION

AI summary

A control method for a touchpad is provided. When a vibration unit is driven, the touchpad enters a touch function restriction mode so that the touchpad undergoes various different controls compared to the normal mode. This helps to avoid erroneous capacitive sensing caused by the driving of the vibration unit, preventing determinations in touch operations and avoiding the accidental triggering of commands or gestures. As a result, it reduces or minimizes the influences on user operations.