Bone Conduction Acoustic Structure for Bass-Vibration Balance
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Solution Overview
Problem
Existing bone conduction headphones generate strong vibrations during low-frequency signal transmission, leading to discomfort and compromised sound quality due to lack of bass, affecting user experience.
Innovation Solution
A bone conduction acoustic device with a spatial low-frequency adjustment plate between the hollow flexure spring and actuator, adjusting the resonance frequency point by altering the stackup and gap in the Z-axis direction, and using magnetic balance to achieve moderate amplitude and balanced sound frequency range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If low-frequency signals are transmitted through the bone conduction acoustic device, then the bass content is improved, but the vibration amplitude becomes excessively large causing discomfort
Solution Approach 1:
The device segments the vibration transmission path by introducing a hollow flexure spring as an independent vibration isolation component between the actuator and the bone conduction transmission structure. This segmentation allows the low-frequency bass signals to be transmitted while the hollow flexure spring absorbs and dampens excessive vibration amplitudes, preventing discomfort to the user.
Solution Approach 2:
The hollow flexure spring acts as an intermediary element between the actuator and the bone conduction transmission structure. It mediates the transmission of low-frequency signals by allowing the bass content to pass through while filtering out excessive vibration amplitudes, thus resolving the contradiction between improving bass content and reducing harmful vibrations.
2Volume of moving object
If the hollow flexure spring and actuator are positioned closer together, then the device size is reduced, but the resonance frequency point shifts affecting sound quality
Solution Approach 1:
The device employs a dynamically adjustable positioning mechanism for the hollow flexure spring and actuator. The spatial low-frequency adjustment plate allows precise adjustment of the distance and relative position between these components along the Z-axis direction, enabling optimization of the resonance frequency point while maintaining a compact device size. This dynamic adjustability ensures that the sound quality parameters can be tuned to meet performance requirements.
3Power
If the gap in the isolation area is reduced, then the magnetic coupling is improved, but the vibration isolation effectiveness decreases
Solution Approach 1:
The device applies local quality differentiation by having different gap sizes in different regions. The isolation area has a specific gap size optimized for vibration isolation, while other regions maintain appropriate gaps for magnetic coupling. This localized optimization allows the system to achieve both good magnetic coupling and effective vibration isolation simultaneously.
Solution Approach 2:
The hollow flexure spring serves as an intermediary structure between the upper and lower magnetic parts. It provides a controlled gap in the isolation area that maintains vibration isolation effectiveness while allowing sufficient magnetic coupling. The flexible nature of the hollow flexure spring enables it to mediate between the conflicting requirements of magnetic coupling and vibration isolation.
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 transmits low-frequency signals with moderate amplitude, balancing the entire sound frequency range, improving user experience and sound quality while reducing production costs and preventing sound leakage.
Implementation Method 1
Bone conduction is a sound transmission method, in which sound is converted into mechanical vibrations of different frequencies, and air sound waves are transmitted through the human skull, bone labyrinth, inner ear lymph fluid, spiral organ, and auditory center
Implementation Method 2
an actuator, which includes an upper magnetic part and a lower magnetic part
Implementation Method 3
adjusts the resonance frequency point of the device
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The application discloses a bone conduction acoustic device and a wearable device, wherein the bone conduction acoustic device comprises an external packaging structure, a hollow cavity is arranged in the external packaging structure, and in the hollow cavity, the following components are arranged: a hollow flexure spring; an actuator, which includes an upper magnetic part and a lower magnetic part, wherein the upper magnetic part and the lower magnetic part are arranged opposite to each other in parallel in the Z-axis direction, and there is a gap to form an isolation area; a spatial low-frequency adjustment plate, which is arranged between the hollow flexure spring and the actuator, wherein the spatial low-frequency adjustment plate adjusts the stackup of the hollow flexure spring and the actuator in the Z-axis direction, and adjusts the gap in the isolation area, wherein the hollow flexure spring cooperates with the spatial low-frequency adjustment plate to adjust the effective vibration area of the hollow flexure spring to adjust the resonance frequency point of the device. The wearable device installed with the above-mentioned bone conduction acoustic device may transmit low-frequency signals with moderate amplitude, balance the entire sound frequency range, achieve better acoustic effects, and significantly improve user experience and product sound quality.