Polymer Waveguide Microphone for RF Noise Immunity
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Solution Overview
Problem
Conventional microphones are susceptible to radio frequency (RF) noise and have a thickness that limits their integration into thinner devices, such as cell phones.
Innovation Solution
A microphone design utilizing a polymer waveguide that modulates light signals in response to acoustic energy, converting them into electrical signals, which is less susceptible to RF noise and can be fabricated with a very thin profile by using a light transmitter, optically aligned transmit, vibrating, and receive sections, and a receiver.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional membrane and capacitor microphone is used, then acoustic energy can be detected, but the device becomes susceptible to RF noise and has increased thickness
Solution Approach 1:
The patent replaces the conventional mechanical membrane and capacitor system with an optical system using a polymer waveguide that modulates light in response to acoustic pressure. This substitution eliminates the mechanical components that are susceptible to RF noise while maintaining acoustic detection capability through optical modulation.
Solution Approach 2:
The patent introduces light as an intermediary carrier between the acoustic input and electrical output. The polymer waveguide modulates light intensity in response to acoustic pressure, and this modulated light is then converted to electrical signals, providing a noise-immune transmission path that avoids direct electrical coupling with RF interference.
2Length of moving object
If a conventional acoustic housing is used, then microphone function is achieved, but the thickness limits device miniaturization
Solution Approach 1:
The patent replaces the traditional mechanical acoustic housing with a polymer waveguide structure that performs both acoustic sensing and optical transmission functions. This integration eliminates the need for separate housing components, achieving thin-profile fabrication while maintaining structural integrity through the waveguide's inherent mechanical properties.
Solution Approach 2:
The polymer waveguide serves multiple functions simultaneously: it acts as the acoustic sensing element, the optical transmission medium, and the structural housing. This multi-functionality consolidates multiple components into a single thin structure, enabling device miniaturization while preserving necessary structural and functional integrity.
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 effectively reduces RF noise interference and allows for the creation of thinner microphones, enhancing their suitability for modern devices like cell phones by using a polymer waveguide to convert acoustic energy into electrical signals through light modulation.
Implementation Method 1
The vibrating section of the waveguide is configured to vibrate in response to received acoustic energy
Implementation Method 2
A light transmitter configured to generate light
Implementation Method 3
a receiver that converts the modulated light signal into a corresponding electrical signal
Data Source
AI summary
An apparatus and method for making a microphone that is not susceptible to RF noise and that can be fabricated to be very thin. The microphone includes a light transmitter configured to generate light, a waveguide having optically aligned transmit, vibrating and receive sections, and a receiver. Light from the transmitter is configured to be transmitted through the transmit section, vibrating section and the receive section of the waveguide, and to the receiver. The vibrating section of the waveguide is configured to vibrate in response to received acoustic energy, so that the light received by the receive section is modulated in proportion to the acoustic energy. In response, the receiver converts the modulated light to an electrical signal that is indicative of the received acoustic energy. Since the microphone of the present invention uses a thin waveguide to modulate the acoustic energy, it is not susceptible to RF noise, and it can be made to have a very thin profile.