CN204681587U - Electret microphone - Google Patents

Abstract

Electret microphone. An electret microphone includes: a casing forming an inner space. The housing has a port extending through the housing. The microphone also includes a first diaphragm and a second diaphragm; a back plate disposed on the first diaphragm. The backplane has a layer of permanently polarized electret material. The first diaphragm and the second diaphragm divide the interior space into a rear space and a front space. Acoustic energy moves through the port causing a first movement of the first diaphragm to generate an electrical signal, and the sound energy also produces a second movement of the second diaphragm effective to reduce the sensitivity of the first diaphragm.

Description

electret microphone

technical field

This application relates to electret microphones, and more particularly to the operation of such devices.

Background technique

Different types of acoustic devices have been used over the years. One type of device is a microphone. Microphones are used in various types of devices, such as personal computers or cellular phones. One type of device is an electret microphone, where the back plate is charged. The diaphragm moves in response to the incoming sound, and an electrical signal is generated following the movement of the diaphragm of the backplane.

Microphones have a response curve that defines the output of the microphone over a range of frequencies. If this response curve is not properly shaped, it will distort the incoming signal. Distortion will make it impossible or difficult for the listener to distinguish incoming sounds.

Problems with existing solutions have resulted in some user dissatisfaction with these existing solutions.

Utility model content

The utility model provides an electret microphone, the electret microphone comprises: a casing, which forms an inner space, and the casing has a port extending through the casing; a first diaphragm and a second diaphragm ; a back plate disposed above the first diaphragm, the back plate has a layer of permanently polarized electret material; wherein the first diaphragm and the second diaphragm divide the interior space into a rear space and the front space; wherein acoustic energy moves through a port causing a first movement of said first diaphragm to generate an electrical signal, and the sound energy produces a second movement of said second diaphragm effective Reduce the sensitivity of the first diaphragm.

Description of drawings

For a more complete understanding of the present disclosure, reference should be made to the following detailed description and accompanying drawings, in which:

1 includes perspective views of electret microphones according to various embodiments of the present invention;

2 includes side views of electret microphones according to various embodiments of the present invention;

3 includes side views of electret microphones according to various embodiments of the present invention;

4 includes graphs of response curves for the electret microphones of FIGS. 1 , 2 and 3 in accordance with various embodiments of the present invention.

Those skilled in the art will appreciate that elements in the figures are shown for simplicity and clarity. It will be further understood that certain actions and/or steps may be described or depicted as appearing in a particular order, while those skilled in the art will understand that such particular order of appearance is not actually necessary. It should also be understood that terms and expressions used herein have ordinary meanings consistent with such terms and expressions in their respective fields of investigation and study, unless special meanings are given herein.

Detailed ways

The method provides an electret microphone with ski slope response. The response of the ski slope allows the listener to correctly distinguish the audio signal with minimal (or no) distortion. More specifically, the ski slope response is obtained by utilizing two diaphragms in the microphone and using the movement of the second diaphragm to reduce the sensitivity of the first diaphragm.

Referring now to FIGS. 1-3 , an electret microphone 100 includes a housing 102 (forming an interior volume or space 104 ). The housing 102 has a port 106 extending through the housing. The microphone 100 also includes a first diaphragm 108 and a back plate 107 . The back plate 107 is disposed above the first diaphragm 108 . The electret material should only be close to the diaphragm 108 so that movement of the diaphragm 109 does not generate an electrical signal. The back plate 107 has a layer of permanently polarized electret material. The first diaphragm 108 and the second diaphragm 109 divide the interior space 108 into a rear space 110 and a front space 112 .

The acoustic energy 101 moves through the port 106 and causes the first diaphragm 108 to undergo a first movement creating an electrical signal, and the acoustic energy 101 also creates a second movement of the second diaphragm 109 which effectively lowers the first diaphragm 108 sensitivity. "Sensitivity" refers to the ratio of generated voltage to sound pressure level (eg, Volts/Pascal).

As shown in FIG. 2 , in one example, the first membrane 108 and the second membrane 109 are horizontally arranged side by side.

As shown in FIG. 3 , in another example, the first diaphragm 108 and the second diaphragm 109 are vertically stacked one above the other.

In other aspects, the backplane 107 includes or includes openings. The purpose of this opening is to allow air trapped between the back plate 107 and the first diaphragm 108 to escape more freely, thereby improving the sensitivity of the microphone at high frequencies. In other examples, the second membrane is constructed of Mylar. Other examples of materials are also possible.

Referring now to FIG. 4 , one example of a response curve 400 for the electret microphone 100 of FIGS. 1-3 is depicted. The y-axis is the response and the x-axis is the frequency. It can be seen that the bottom 402 of the curve 400 is substantially frequency invariant and this portion 402 is referred to as the ski slope.

Preferred embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. It should be understood that the illustrated embodiments are exemplary only, and should not be taken as limiting the scope of the invention.

Claims (5)

1. A kind of electret microphone, this electret microphone comprises: a housing forming an interior space and having a port extending through the housing; a first diaphragm and a second diaphragm; a backplate disposed over the first diaphragm, the backplate having a layer of permanently polarized electret material; Wherein, the first diaphragm and the second diaphragm divide the internal space into a rear space and a front space; wherein acoustic energy moves through the port causing a first movement of the first diaphragm to generate an electrical signal, and the sound energy produces a second movement of the second diaphragm effective to reduce the first Diaphragm sensitivity. 2. The electret microphone according to claim 1, wherein the first diaphragm and the second diaphragm are horizontally arranged side by side. 3. The electret microphone according to claim 1, wherein the first diaphragm and the second diaphragm are arranged vertically up and down. 4. The electret microphone of claim 1, wherein the back plate includes an opening. 5. The electret microphone of claim 1, wherein the second diaphragm is constructed of Mylar.