Haptic Feedback Device Reducing Acoustic Noise via Missing Fundamental

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Solution Overview

Problem

Haptic feedback devices generate discomforting acoustic noise when vibrating to provide feedback, causing user discomfort due to discontinuous changes in noise frequency with touch position.

Innovation Solution

A haptic feedback device that includes a position obtaining unit, a carrier signal generation unit, an acoustic signal generation unit, and a driving signal generation unit, which generate a driving signal by combining carrier signals and acoustic signals with harmonics corresponding to a predetermined fundamental frequency, reducing variations in acoustic noise by making the fundamental frequency audible through the missing F0 phenomenon.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the panel vibrates to provide haptic feedback, then haptic feedback is provided to the user, but acoustic noise is generated causing user discomfort

Engineering Contradiction:

Improvehaptic feedback qualityVSAvoidacoustic noise

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The invention converts the harmful acoustic noise into a beneficial effect by utilizing the missing fundamental phenomenon. When the panel vibrates at frequencies that produce acoustic noise, the system intentionally omits the fundamental frequency component and only plays harmonic components (e.g., 2nd, 3rd, 4th harmonics). The human auditory system then perceives the fundamental frequency as if it were present, but at a lower volume level, thereby reducing discomfort while maintaining haptic feedback quality.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The system changes the frequency parameters of the vibration signal by removing the fundamental frequency component and retaining only harmonic components. This parameter transformation allows the panel to vibrate at frequencies effective for haptic feedback while the acoustic output contains only harmonic frequencies, which the human ear perceives as a softer, less discomforting sound at the fundamental frequency.

Inventive Principle:

Principle #35Parameter changes

2Ease of operation

If the vibration frequency changes with touch position, then haptic feedback is optimized for different positions, but discontinuous noise frequency changes cause user discomfort

Engineering Contradiction:

Improvehaptic feedback adaptabilityVSAvoiddiscontinuous noise variations

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The invention applies the missing fundamental phenomenon consistently across all touch positions. When the vibration frequency changes with touch position, the system always omits the fundamental frequency component and plays only harmonics. This converts the potentially harmful discontinuous noise variations into a beneficial consistent auditory perception, where users perceive a continuous fundamental frequency tone regardless of touch position changes.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The system creates an equipotential auditory experience by maintaining the perception of a consistent fundamental frequency across all touch positions. By using harmonics to represent the fundamental frequency uniformly regardless of position, the system eliminates auditory discontinuities and creates a consistent perceptual baseline, making position transitions imperceptible to the user's ear.

Inventive Principle:

Principle #12Equipotentiality

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 device effectively reduces user discomfort by minimizing discontinuous changes in acoustic noise, allowing continuous perception of a consistent sound frequency, thereby enhancing the haptic feedback experience.

Implementation Method 1

an actuator configured to provide haptic feedback to the user by vibrating the panel in accordance with the driving signal

Methodology Applied

Scientific EffectVibration: Vibration

Implementation Method 2

generate an acoustic signal having a plurality of harmonics which correspond to a predetermined fundamental frequency... making the fundamental frequency audible through the missing F0 phenomenon

Methodology Applied

Scientific EffectMissing fundamental phenomenon:

Data Source

PatentEP2811375B1Tactile-feel presentation device and method for presenting tactile feel

Publication Date: 2017.03.08 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD

AI summary

A haptic feedback device (100) which provides haptic feedback to a user touching a panel, the haptic feedback device including: the panel (101); a position obtaining unit (102) which obtains a position touched on the panel by the user; a carrier signal generation unit (104) which generates a carrier signal having a first frequency component when the position touched by the user is a first position, and generates a carrier signal having a second frequency component when the position touched by the user is a second position; an acoustic signal generation unit (105) which generates an acoustic signal having harmonics corresponding to a predetermined fundamental frequency; a driving signal generation unit (106) which generates a driving signal by adding together the carrier signal and the acoustic signal; and an actuator (107) which provides haptic feedback to the user by vibrating the panel in accordance with the driving signal.