Bone Conduction Microphone Monolayer PCB Design
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Solution Overview
Problem
Existing bone conduction microphones are not ultra-thin, increase material costs, and have complex package processes due to stacked circuit boards.
Innovation Solution
A bone conduction microphone design featuring a monolayer circuit board with an acoustic channel, a vibration assembly dividing the receiving space into cavities, and a MEMS chip with a back cavity, where airflow generated by the vibration assembly is transmitted through the acoustic channel and cavities to improve sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If stacked circuit boards are used to form a circuit board assembly, then the bone conduction microphone can be assembled, but the thickness increases and material cost increases
Solution Approach 1:
The patent merges multiple circuit boards into a single monolayer circuit board that integrates all necessary functional layers. The monolayer circuit board combines the first circuit board and second circuit board functions into one unified structure, eliminating the need for stacking while maintaining all required electrical connections and functional capabilities.
Solution Approach 2:
The monolayer circuit board serves multiple functions simultaneously: it provides structural support, electrical connections, acoustic channel formation, and housing for both the vibrator and MEMS chip. This multi-functional design replaces what would traditionally require multiple separate components and layers.
2Ease of manufacture
If stacked circuit boards are used, then the bone conduction microphone can be assembled, but the package process becomes complex
Solution Approach 1:
The patent combines multiple assembly steps into a single integrated package process. By using a monolayer circuit board that already has all necessary traces, vias, and structural features built-in during manufacturing, the subsequent assembly steps are dramatically reduced. The circuit board assembly is formed as a single integrated component rather than through stacking and welding multiple separate boards.
3Length of stationary object
If a monolayer circuit board is used, then the thickness is reduced and cost is lowered, but the acoustic channel design becomes more challenging
Solution Approach 1:
The patent applies different structural characteristics to different regions of the monolayer circuit board. The acoustic channel is designed with specific local properties (openings, cavities, and vibration isolation features) that are integrated into particular areas of the circuit board, allowing complex acoustic functionality within a simple overall monolayer structure.
Solution Approach 2:
The patent nests the acoustic channel features within the monolayer circuit board structure. The vibrator cavity, MEMS chip cavity, and acoustic channels are all integrated into the single circuit board layer, with the vibrator positioned to vibrate against the circuit board and transfer vibrations through embedded acoustic pathways to the MEMS chip.
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 design achieves an ultra-thin profile, reduces material costs, simplifies the package process, and enhances sensitivity and signal-to-noise ratio by transmitting vibration signals to the MEMS chip through differential paths.
Implementation Method 1
a vibration assembly received in the receiving space, dividing the receiving space into a first cavity and a second cavity
Implementation Method 2
the acoustic channel is configured to connect the first cavity with the back cavity; an airflow generated by the vibration of the vibration assembly is transmitted to one side of the MEMS chip through the first cavity, the acoustic channel and the back cavity successively
Implementation Method 3
a MEMS chip including a back cavity, received in the second cavity enclosed by the vibration assembly and the circuit board, and mounted on the circuit board; the airflow is transmitted to the other side of the MEMS chip through the second cavity
Data Source
AI summary
The present disclosure discloses a housing; a monolayer circuit board engaged with the housing for enclosing a receiving space, and including an acoustic channel; a vibration assembly received in the receiving space, dividing the receiving space into a first cavity and a second cavity; and a MEMS chip including a back cavity, received in the second cavity enclosed by the vibration assembly and the circuit board, and mounted on the circuit board; the acoustic channel is configured to connect the first cavity with the back cavity; an airflow generated by the vibration of the vibration assembly is transmitted to one side of the MEMS chip through the first cavity, the acoustic channel and the back cavity successively; the airflow is transmitted to the other side of the MEMS chip through the second cavity. The bone conduction microphone in the present disclosure has low height and higher sensitivity.