Laser MEMS microphone

Abstract

The invention discloses a laser MEMS microphone, which comprises a light source and a microphone structure, and is characterized in that the microphone structure comprises a substrate, a back plate, avibration sound film, a front cavity formed by the substrate and the vibration sound film, and a rear cavity formed by the vibration sound film and the back plate; the light source is a VCSEL, and the back plate and the vibration sound film are respectively provided with a plurality of sound holes which are manufactured through an MEMS technology. The VCSEL emits a laser beam to the vibration sound film; the vibration sound film reflects part of the laser beam to the VCSEL resonant cavity; the reflected laser beam carries sound information of vibration of the vibration sound film, and the partially reflected laser beam is mixed with laser in the VCSEL resonant cavity to generate a laser self-mixing interference effect; the output power and frequency of the VCSEL are changed, and the junction voltage on the VCSEL is extracted; and after amplification and demodulation, the signals are converted into audio waveforms, thereby realizing conversion from sound signals to electric signals. The laser MEMS microphone is high in pickup signal-to-noise ratio, small in size and high in electromagnetic interference resistance.

Description

technical field [0001] The invention belongs to the technical field of microphones, in particular to a laser MEMS microphone which converts acoustic signals into electrical signals through laser. Background technique [0002] A microphone is a transducer that converts sound into electrical signals. Microphones have been used in traditional fields such as telephones, hearing aids, recording engineering, and television stations, and are now used in modern fields such as speech recognition, ultrasonic sensing, and automated performance control. Microphones of different principles have different ways of converting the air pressure vibrations produced by sound waves into electrical signals. The common ones are dynamic microphones, the vibration of the diaphragm drives the movement of the coil suspended in the magnetic field, and a weak voltage is generated by the change of the magnetic field; the capacitive microphone uses the diaphragm as the plate of the capacitor, and the cha...

AI Technical Summary

Problems solved by technology

However, most MEMS microphones are currently designed based on condenser microphones. Compared with traditional condenser microphones, they are only smaller in size, and the signal-to-noise ratio and anti-electromagnetic interference ability have not been significantly improved.

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