MEMS Bone Conduction Sensor Closed Cavity Noise Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional MEMS microphones face challenges in achieving high signal-to-noise ratios due to ambient noise interference, and the inclusion of G-sensors to detect bone vibrations increases manufacturing costs for products like hearing aids and Bluetooth headsets.
Innovation Solution
A MEMS-based bone conduction sensor with a closed cavity containing a uniaxial or biaxial accelerometer sensor and an ASIC processing chip, integrated with a primary and secondary microphone, audio codec, and microcontroller, which reduces environmental interference and production costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional MEMS microphones are used to capture sound waves through air, then the microphone can detect vocal cord vibrations, but ambient noise interference greatly reduces voice call quality and signal-to-noise ratio
Solution Approach 1:
The patent extracts the harmful air conduction path and replaces it with direct bone conduction contact. The sensor is placed in direct contact with the temporal bone, extracting the voice signal directly from bone vibrations while eliminating the air medium that carries ambient noise.
Solution Approach 2:
The patent introduces bone (temporal bone) as an intermediary medium to transmit voice signals directly to the sensor. This intermediary path bypasses the air medium that causes noise interference, providing a cleaner signal transmission channel.
2Measurement precision
If a G-sensor (Accelerometer-sensor) is adopted as a bone conduction sensor to detect bone vibrations, then voice quality improves, but manufacturing costs of hearing aids and Bluetooth headsets increase
Solution Approach 1:
The patent replaces the expensive G-sensor with a simpler, lower-cost accelerometer sensor that is sufficient for bone conduction detection. This substitution uses a more economical component while maintaining the necessary detection functionality for voice signals.
Solution Approach 2:
The patent changes the sensing parameters by using an accelerometer designed for bone conduction applications rather than general-purpose G-sensors. This parameter change optimizes the sensor for the specific application, reducing costs while maintaining detection accuracy.
3Ease of manufacture
If a uniaxial or biaxial accelerometer sensor is placed in a closed cavity adjacent to ear bones, then production costs are reduced and environmental interference is minimized, but the device structure becomes more complex
Solution Approach 1:
The patent merges the accelerometer sensor, ASIC processing chip, and cavity structure into an integrated assembly. This combination simplifies the overall device architecture by integrating multiple components into a unified structure that reduces total system complexity.
Solution Approach 2:
The closed cavity structure serves multiple functions: it protects the sensor, provides a stable mounting platform, reduces environmental interference, and integrates with the ear-mounted device housing. This multi-functionality reduces the need for additional separate 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 enhances voice quality by reducing ambient noise interference and lowers manufacturing costs, enabling mass production of ear-mounted devices such as hearing aids and Bluetooth headsets with improved performance.
Implementation Method 1
a uniaxial or biaxial accelerometer sensor arranged to be adjacent to bones of a human ear
Implementation Method 2
The G-sensor is one of the MEMS sensors. It can detect changes in acceleration. For example, shaking, falling off, rising up, lowering down and other movements may be converted into electric signals by the G-sensor.
Implementation Method 3
an ASIC (application-specific integrated circuit) processing chip coupled to the uniaxial or biaxial accelerometer sensor, the ASIC processing chip being provided with an output end for a vibration signal
Implementation Method 4
a primary microphone for sensing sound wave signals
Implementation Method 5
a secondary microphone spaced from the primary microphone by a set distance
Implementation Method 6
an audio codec coupled to the primary microphone and the secondary microphone
Implementation Method 7
a microcontroller coupled to a signal output end of the bone conduction sensor and to a signal input end of the audio codec
Data Source
AI summary
The invention relates to the field of electronic technology, and more particularly, to a microphone structure. A MEMS (Micro-Electro-Mechanical System)-based bone conduction sensor comprises: a closed cavity within which a uniaxial or biaxial accelerometer sensor is arranged to be adjacent to bones of a human ear; an ASIC (application-specific integrated circuit) processing chip coupled to the uniaxial or biaxial accelerometer sensor, the ASIC processing chip being provided with an output end for a vibration signal. By adopting the above-mentioned technical solution, a bone conduction sensor with a closed cavity is provided in the present invention. Furthermore, a uniaxial or biaxial accelerometer sensor and an ASIC processing chip are arranged inside the closed cavity. In this way, the production costs are reduced, and interference of the sensor caused by ambient environment is reduced.