Dual-Use Haptic Trackpad Speaker for Space-Limited Audio Feedback
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Solution Overview
Problem
Mobile computing devices face space constraints due to the inclusion of both trackpads and loudspeakers, and existing haptic trackpads lack sufficient tactile feedback and audio capabilities.
Innovation Solution
A haptic trackpad loudspeaker design that integrates a printed circuit board, resilient spacers, a touch sensor, and a haptic element within a device chassis, allowing it to function as both a haptic feedback device and a loudspeaker, utilizing orthogonal oscillation for haptic and acoustic operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If traditional separate trackpad and loudspeaker designs are used, then each component can perform its dedicated function, but the device occupies excessive space within the computing device
Solution Approach 1:
The patent combines a trackpad and loudspeaker into a single integrated assembly where the touch-sensitive surface serves dual purposes: as an input device and as a speaker diaphragm. The haptic element is positioned behind the touch sensor to drive acoustic oscillation, while the touch sensor itself functions as the radiating surface for sound waves, eliminating the need for separate components.
Solution Approach 2:
The touch sensor serves multiple functions simultaneously: it acts as the input surface for touch detection, as the diaphragm for acoustic radiation, and as the radiating surface for sound output. This multi-functionality allows the single component to replace what would traditionally require separate trackpad and speaker assemblies.
2Reliability
If haptic feedback is added to a trackpad, then tactile feedback capability is improved, but the device complexity and space requirements increase
Solution Approach 1:
The haptic element is integrated directly behind the touch sensor within the same assembly, combining tactile feedback generation with the acoustic radiation function. This eliminates the need for separate haptic motors or additional structural components that would traditionally be required for haptic feedback.
Solution Approach 2:
The haptic element serves dual purposes: generating tactile feedback for touch input detection and driving acoustic oscillation for sound output. This multi-functionality reduces overall device complexity by eliminating the need for separate haptic and acoustic actuation systems.
3Volume of moving object
If a touch sensor is used as both haptic surface and diaphragm, then space efficiency is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The assembly is divided into distinct functional layers: the touch sensor layer, the haptic element layer, and the acoustic radiation layer. This segmentation allows each component to be manufactured and tested independently before assembly, reducing the overall manufacturing precision requirements while maintaining space efficiency.
Solution Approach 2:
The haptic element acts as an intermediary between the touch sensor and the acoustic environment, providing a mechanical coupling that translates touch interactions into both tactile feedback and acoustic oscillation. This intermediary structure simplifies the manufacturing requirements by providing a clear interface between 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 haptic trackpad loudspeaker efficiently uses space by replacing or enhancing traditional speakers, providing enhanced user experience with improved tactile feedback and audio performance, including wider frequency range and central channel functionality.
Implementation Method 1
driving substantially orthogonal oscillation of the touch sensor using the haptic element at frequencies less than 400 Hz to provide haptic feedback
Implementation Method 2
driving piston mode substantially orthogonal oscillation of the touch sensor using the haptic element at frequencies from 400 Hz to 3 kHz to provide acoustic oscillation
Implementation Method 3
driving distributed mode substantially orthogonal oscillation of the touch sensor using the haptic element at frequencies above 3 kHz to provide acoustic oscillation
Implementation Method 4
an array of resilient spacers bonding a first side of the PCB to a bottom surface of the device chassis within the recess
Data Source
AI summary
Current mobile devices that feature force feedback touchpads include haptic engines that operate in a narrow bandwidth and therefore cannot be used as a dual-purpose center channel for media playback. Further, a separate dedicated loudspeaker for a center channel would add cost and reduce integration space. The presently disclosed dual-use haptic trackpad loudspeaker can enable an enhanced audio experience without the need for an additional dedicated loudspeaker. The dual-use haptic trackpad loudspeaker can be used for haptics feedback as well as provide audio output over the frequency range 400 Hz to 10 kHz. The dual-use haptic trackpad loudspeaker may use a tuned spring-mass actuator and adopt mechanical properties to provide a specific desired mechanical compliance to the dual-use haptic trackpad loudspeaker.