MEMS Sound Transducer for Ambient Temperature and Wind Velocity Detection
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Solution Overview
Problem
There is a need for sensor elements that can accurately detect various ambient conditions, such as temperature and wind velocity, in mobile devices without requiring additional space or complex setups, and existing technologies struggle to provide high accuracy in ambient temperature measurements without equilibrating with the surroundings.
Innovation Solution
A membrane-based MEMS sound transducer is used as both an audio microphone and an ultrasonic transceiver, capable of detecting ambient conditions by utilizing its membrane structure and counterelectrode structure to generate and read ultrasonic signals, allowing for the determination of temperature and wind velocity through signal propagation time analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single MEMS sound transducer is used for both audio microphone and ultrasonic transceiver functions, then device complexity and space requirements are reduced, but the ability to accurately detect multiple ambient conditions simultaneously is compromised
Solution Approach 1:
The patent applies multi-functionality by enabling a single MEMS sound transducer to operate in multiple frequency ranges (audio and ultrasonic) and multiple modes (microphone and transceiver). The transducer can detect audio signals, generate ultrasonic signals, and receive ultrasonic signals, thereby eliminating the need for separate components while maintaining detection accuracy through sophisticated signal processing
Solution Approach 2:
The patent employs dynamic operation by allowing the MEMS transducer to switch between different operating modes and frequency ranges. The transducer can dynamically adjust its function based on operational requirements, transitioning between audio frequency detection and ultrasonic frequency transmission/reception to perform multiple measurement tasks
2Measurement precision
If traditional temperature sensing methods are used, then the device must equilibrate with surroundings for accurate measurement, but this increases measurement time and reduces responsiveness to ambient temperature changes
Solution Approach 1:
The patent replaces traditional thermal equilibrium-based temperature sensing with an acoustic measurement approach. By using ultrasonic signal propagation time through the ambient medium, the system determines temperature based on the speed of sound relationship with temperature, eliminating the need for thermal equilibration and enabling immediate temperature measurement
Solution Approach 2:
The patent changes the measurement parameter from thermal contact (requiring equilibration) to acoustic propagation (instantaneous measurement). The system measures temperature by analyzing the propagation time of ultrasonic signals through air, utilizing the known relationship between sound speed and temperature to calculate ambient temperature without thermal exchange
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
This solution enables accurate detection of multiple ambient parameters with high precision, using a single MEMS component, without increasing the device's size or requiring separate transmitter and receiver components, and avoids the need for the device to equilibrate with its surroundings for accurate temperature measurement.
Implementation Method 1
the membrane structure and/or the counterelectrode structure are/is excited electrostatically (capacitively) or piezoelectrically in order to generate sufficiently strong sound pressure levels at ultrasonic frequencies
Implementation Method 2
the membrane structure and/or the counterelectrode structure are/is excited electrostatically (capacitively) or piezoelectrically in order to generate sufficiently strong sound pressure levels at ultrasonic frequencies
Implementation Method 3
detect an audio output signal of the MEMS sound transducer on the basis of a deflection of the membrane structure relative to the counterelectrode structure, said deflection being brought about by an acoustic sound pressure change
Implementation Method 4
Given a known or predefined value for the distance covered by the ultrasonic transmission signal through the ambient atmosphere, the temperature in the ambient atmosphere can be determined for example from the resulting propagation time
Data Source
AI summary
A MEMS component includes a MEMS sound transducer having a membrane structure and an assigned counterelectrode structure, and a circuit unit, which is electrically coupled to the MEMS sound transducer and which in a first operating mode of the MEMS sound transducer in the audio frequency range detects an audio output signal of the MEMS sound transducer on the basis of a deflection of the membrane structure relative to the counterelectrode structure, the deflection being brought about by an acoustic sound pressure change, and in a second operating mode of the MEMS sound transducer in the ultrasonic frequency range to drive and read the MEMS sound transducer as an ultrasonic transceiver.