Optical MEMS Microphone Diaphragm for High-Sensitivity Sound Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional microphones based on capacitors face limitations in achieving high sensitivity and flat frequency response, failing to meet the increasing performance demands of consumers.
Innovation Solution
An MEMS optical microphone design incorporating a diaphragm with light flaps that form an aperture in response to sound pressure, utilizing an optoelectronic module to convert light intensity and phase into electrical signals, enhanced by anchor structures and multiple light flaps for improved compliance and sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional capacitor-based microphones are used, then the structure is simple and manufacturing is easy, but sensitivity and frequency response performance are insufficient
Solution Approach 1:
The patent replaces the traditional capacitor-based electrical measurement system with an optical measurement system. A light source emits light through the diaphragm to a photodetector, and sound-induced diaphragm vibrations modulate the light intensity, which is then converted to electrical signals. This optical substitution enables higher sensitivity and flatter frequency response while managing structural complexity through integrated design.
Solution Approach 2:
The diaphragm is segmented into multiple functional regions including a light-transmissive aperture portion and anchor portions. The aperture portion allows light passage for optical detection, while the anchor portions provide mechanical support and electrical connections. This segmentation enables the diaphragm to simultaneously fulfill mechanical, optical, and electrical functions, improving measurement precision without excessive complexity.
2Measurement precision
If a light flap is added to the diaphragm to control light transmission, then sensitivity improves, but manufacturing complexity increases
Solution Approach 1:
The light flap's physical parameters (width, length, hinge position) are optimized to achieve appropriate light transmission control. By adjusting these geometric parameters during design, the flap can be tuned to provide the desired modulation of light intensity in response to sound pressure, improving sensitivity while maintaining manufacturability through standard geometric definitions.
Solution Approach 2:
The light flap is merged with the diaphragm structure, forming an integrated component rather than a separate assembly. The flap is directly patterned onto the diaphragm membrane during fabrication, combining the light modulation function with the existing diaphragm structure. This merging reduces manufacturing steps and simplifies production while achieving improved light transmission control.
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 high sensitivity and flat frequency response, enabling better performance by controlling light transmission through aperture changes, thereby enhancing acoustic-electrical signal conversion.
Implementation Method 1
an optoelectronic module including an electromagnetic radiation source and a sensor, the electromagnetic radiation source and the sensor are arranged on opposite sides of the diaphragm, and a light beam emitted by the electromagnetic radiation source passes through the aperture and reaches the sensor
Data Source
AI summary
An MEMS optical microphone, including: a shell including an inner cavity and a sound inlet that communicates the inner cavity with outside; a MEMS module including a diaphragm suspended in the inner cavity, a light flap is formed in the diaphragm, when an acoustic pressure is applied, an aperture is formed by opening of the light flap, and a size of the aperture increases or decreases with a magnitude of the acoustic pressure applied; an optoelectronic module including an electromagnetic radiation source and a sensor arranged on opposite sides of the diaphragm, and a light beam passes through the aperture to the sensor; and an integrated circuit module electrically connected with the optoelectronic module. Advantages of high sensitivity and flat frequency response are realized.