Haptic Actuator Tuning Feature Reduces Audible Noise
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Solution Overview
Problem
Haptic actuators in electronic devices often produce undesirable audible noise in addition to the intended tactile feedback, which can be distracting and conflict with their purpose of providing discreet notifications or simulating actions like button clicks.
Innovation Solution
Incorporating tuning features such as recesses, protrusions, or plates within the haptic actuator's housing to selectively reduce the amplitude of audible frequencies within specific ranges, typically between 1 kHz and 5 kHz, while maintaining the haptic output by minimizing changes to other frequency components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a haptic actuator is designed to produce strong haptic output, then the tactile feedback is improved, but audible noise in the frequency range of 1 kHz to 5 kHz increases
Solution Approach 1:
The patent applies local quality by introducing specific structural features (recesses, protrusions, or plates) at particular locations on the housing to selectively attenuate audible frequencies while preserving haptic output in other areas. These localized modifications create frequency-selective damping without compromising the overall haptic performance of the actuator.
Solution Approach 2:
The patent utilizes parameter changes by modifying the physical properties of the housing structure through added mass, stiffness variations, or damping characteristics introduced by the tuning features. These parameter modifications are specifically designed to attenuate the 1 kHz to 5 kHz frequency range while maintaining the haptic actuator's operational parameters intact.
2Object-generated harmful factors
If tuning features are added to reduce audible noise, then the noise level is reduced by up to 10 dBA, but the device complexity increases
Solution Approach 1:
The patent merges the noise reduction function with the existing housing structure by integrating tuning features directly into the housing design. Rather than adding separate noise control components, the recesses, protrusions, or plates are incorporated as part of the housing itself, thereby reducing audible noise without proportionally increasing device complexity.
Solution Approach 2:
The tuning features serve multiple functions: they act as both structural elements of the housing and as acoustic dampers for specific frequency ranges. This multi-functionality allows the housing to simultaneously provide mechanical support and noise attenuation, reducing the need for additional dedicated noise control components.
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 effectively reduces unwanted noise by up to 10 dBA in the targeted frequency range without significantly altering the tactile feedback, resulting in a quieter haptic actuator that maintains its intended functionality.
Implementation Method 1
Electronic device having a tuned resonance haptic actuation system
Data Source
AI summary
An electronic device includes an enclosure, a display positioned with the enclosure and defining a front face of the electronic device, and a haptic actuator positioned within the enclosure. The haptic actuator includes a housing comprising a wall and a movable mass positioned within the housing and configured to move within the housing to cause the haptic actuator to produce a vibrational response. The vibrational response includes a first component within a frequency range and a second component outside of the frequency range and providing a haptic output portion of the vibrational response. The haptic actuator also includes a tuning feature incorporated with the wall and configured to reduce the first component of the vibrational response while substantially maintaining the haptic output portion of the vibrational response.