Process for making backing electrode electret condenser type microphones

A condenser microphone and electret technology, applied in sensors, electrical components, etc., can solve the problems of poor stability, inability to improve the sensitivity of the microphone, affecting product performance, etc., and achieve the effect of ensuring repeatability

Inactive Publication Date: 2008-03-26
AAC TECH PTE LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

It is difficult to ensure the consistency of tension when the diaphragm is attached to the support ring
If the diaphragm is stretched too tightly, excessive tension will not only make the sensitivity of the microphone unable to be improved, but also cause irreversible plastic changes in the diaphragm, affecting the consistency and stability of the performance indicators of the microphone
In addition, when the tension of the diaphragm is too high, in order to make the sensitivity of the microphone reach a predetermined value, the surface charge density of the electret film must be increased, and the stability of the resident charge of the electret material will deteriorate when the charge density is too high. This also affects the stability of the microphone sensitivity
Conversely, if the tension of the diaphragm is too small, the diaphragm will easily wrinkle, and the coating quality will deteriorate when the nickel film is evaporated, and after being assembled into a microphone, the diaphragm will be attached to the back plate due to electrostatic attraction, affecting product performance

Method used

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  • Process for making backing electrode electret condenser type microphones
  • Process for making backing electrode electret condenser type microphones
  • Process for making backing electrode electret condenser type microphones

Examples

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Embodiment Construction

[0031] DETAILED DESCRIPTION OF THE INVENTION The present invention will be described in detail below with reference to the accompanying drawings.

[0032] The back electret condenser microphone includes several core components: a diaphragm assembly (see Figure 1), a back plate covered with an electret film material, a gasket, and a PCB board with an impedance conversion circuit attached. The above components together with the back plate supporting device and the connecting device are packaged in a casing with a sound transmission hole.

[0033] The electroacoustic performance indicators such as sensitivity, frequency response range and curve flatness of the back electret condenser microphone are mainly determined by the following factors: the surface charge density of the electret, the tension of the diaphragm, the diaphragm and the back plate The distance and performance of the impedance transformer that outputs the electrical signal of the microphone. In order to effectivel...

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Abstract

This invention relates to back electret capacitor microphone process method, which comprises the following steps: stretching the polyester film on the frock to form one fixation diaphragm and adjusting the film resonance frequency within designed range in the testing sound field to control the tension force place of the film; evaporating one layer nickel film with certain thickness in vacuum environment and again adjusting film tension force and then sticking it to one set of supportive rings; accomplishing flatting, baking and dividing programs to accomplish single diaphragm element process.

Description

Technical field: [0001] The invention relates to a manufacturing method of a back pole electret condenser microphone. Background technique: [0002] The pressure condenser microphone adopting the back pole electret method uses polyester film as the diaphragm, and its strength is usually 1 to 2 orders of magnitude smaller than that of the metal film, so the equivalent effect of this type of diaphragm is smooth (this force smooth determines the diaphragm f 01 ) is mainly composed of the rear cavity V 2 contribute. According to the theoretical derivation of common pressure-type condenser microphones, it is not difficult to conclude that the open-circuit sensitivity of pressure-type electret microphones in the main working frequency band is: [0003] E 0 = σd ϵ 2 · C A 2 ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H04R31/00
Inventor 潘政民孟珍奎
Owner AAC TECH PTE LTD
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