Particle vibration velocity measurement sensitive structure and preparation method thereof

Abstract

The invention relates to a particle vibration velocity measurement sensitive structure and a preparation method thereof. A bridge hole is formed in a silicon substrate, a first electrode is arranged on one side of the bridge hole, a second electrode and a third electrode are arranged on the other side of the bridge hole, a first thin wire and a second thin wire are arranged above the bridge hole,the first thin wire and the second thin wire are arranged in parallel and keep a fine pitch, one end of each of the two thin wires is respectively connected with the first electrode, the other end ofeach of the two thin wires is respectively connected with the second electrode and the third electrode, and both the first thin wire and the second thin wire have a structure that both end parts of the thin wire are curved and the middle part of the thin wire is a straight rectangular shape; and the width and thickness of the middle part of the thin wire are greater than the width and thickness ofboth end parts of the thin wire. According to the scheme of the invention, both end parts of each thin wire adopt a narrow, thin and curved unique structure, the effective cross-sectional area of heat conduction through the thin wires can be reduced, the length of a heat transfer path can also be increased, and thus the finite length boundary heat conduction effect of the sensitive structure canbe effectively suppressed, and the response characteristics in low frequency bands can be improved.

Description

technical field [0001] The invention relates to a particle vibration velocity measurement sensitive structure and a preparation method. Background technique [0002] In a large number of acoustic measurement applications, because the sound intensity measurement and its spectrum analysis have unique advantages in the study of the characteristics of the noise source, it has become a powerful tool for acoustic research. Usually, the acquisition of sound intensity information requires the measurement of sound pressure and particle velocity in the sound field. [0003] The sensitive structure of the existing particle vibration velocity sensor is to prepare a sensitive structure composed of several metal platinum resistance wires (thin wires) that are very close to each other on the silicon substrate by using the MEMS process technology, which can directly measure the spatial sound field The vibration velocity of media molecules caused by propagation—the vibration velocity of sou...

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Problems solved by technology

[0004] The disadvantage of the existing particle velocity measurement sensitive structure is that due to the material properties of the above-mentioned particle velocity measurement sensor sensitive structure and its topological structure have a finite length boundary heat conduction effect, the loss rate of heat from the boundary is higher than that caused by low-frequency sound waves. The heat exchange rate caused by the sensor makes the response characteristics of the sensor worse in the low frequency band

In the low-frequency band below 100Hz, the sensitivity of the particle velocity measurement sensor is significantly attenuated as the frequency decreases, causing distortion of the acoustic signal in reception and subsequent processing, and a decrease in the signal-to-noise ratio, which makes the lower limit of the effective working frequency of the sensor insufficient.

Since most of the research fields such as noise characteristic analysis and sound source target detection are mainly focused on low-frequency sound waves, this also limits the wide application of this particle velocity measurement sensor.

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