CN213462321U

CN213462321U - Full shielding structure of electret microphone

Info

Publication number: CN213462321U
Application number: CN202022905931.XU
Authority: CN
Inventors: 王晓杰
Original assignee: Weifang Aoshi Electronics Co ltd
Current assignee: Weifang Aoshi Electronics Co ltd
Priority date: 2020-12-05
Filing date: 2020-12-05
Publication date: 2021-06-15
Anticipated expiration: 2030-12-05

Abstract

The utility model discloses a full shielding structure of an electret microphone, which belongs to the technical field of microphone interference signal shielding and comprises a circuit board body, wherein the circuit board body is connected with a convex part, and a lead-out wire is arranged on the convex part; the utility model discloses a protrusion is located on this external bulge of circuit board to the lead-out wire for the metal forming in the one side of circuit board body can remain completely, and when circuit board body and shell cooperation, circuit board body and shell can constitute a complete confined metal shielding casing, thereby can effectually resist the interference signal who shields outside each frequency channel.

Description

Full shielding structure of electret microphone

Technical Field

The utility model relates to a microphone interference signal shielding technical field, concretely relates to full shielding structure of electret microphone.

Background

With the continuous progress of electronic technology and the continuous improvement of the living standard of people, the electret microphone used as the input end of the electroacoustic device is more and more widely applied, the annual output can be estimated to reach billions, and a wider market is formed.

Electret microphones are usually composed of two parts, an acoustic-electric conversion and an impedance transformation. The key element of the sound-electricity conversion is a vibrating membrane which is a very thin non-metal material, one surface of the vibrating membrane is plated with a layer of metal film in a vacuum evaporation mode, and then after the vibrating membrane is electret by a high-voltage electric field, opposite charges are respectively resident on the two surfaces; the gold-evaporated surface of the diaphragm faces outwards and is communicated with the metal shell; the other side of the diaphragm is separated from the metal plate by a thin insulating gasket. Thus, a capacitor is formed between the diaphragm and the metal plate. When the electret diaphragm encounters acoustic vibration, the electric field across the capacitor is caused to change, thereby producing an alternating voltage that varies with the acoustic wave. Meanwhile, in an electret microphone, a field effect transistor is generally provided for impedance conversion and pre-amplification.

There are two main connection modes between the electret microphone and the circuit, namely source output and drain output. The source output is similar to the emitter output of a transistor, and three lead-out wires are needed; the output of the drain electrode is similar to the common emitter of the transistor, and only two lead wires are needed.

With the continuous progress of wireless communication technology, the density of signal transmitting base stations (especially applied to the field of mobile phone communication) is higher and higher, interference signals of each frequency band (currently, 2.5GMHz is the most common) are brought, and the interference intensity is higher and higher.

The electret microphone as the front-end device of the man-machine conversation is undoubtedly affected by the above mentioned interference signal, and the countermeasure in the industry is basically to arrange various types of filter elements on the circuit inside the electret microphone, and in the concrete practice, the filter elements must be attached to the circuit board. In order to realize signal output, one side of the circuit board must be provided with a lead-out wire, the lead-out wire usually has an output end and a grounding end, and in order to ensure that the signal is not short-circuited, a part of the metal foil between the two terminals must be etched away to form an insulating tape, and the existence of the insulating tape part results in that the interior of the electret microphone cannot be completely shielded, and thus the electret microphone cannot completely resist interference signals.

SUMMERY OF THE UTILITY MODEL

To the problem that exists among the prior art, the utility model provides a pair of full shielding structure of electret microphone, the metal forming of circuit board body one side can remain completely for circuit board body and shell can constitute a complete confined metal shield casing, thereby and effectual realization is resisted and is shielded each frequency channel interference signal's purpose.

In order to realize the purpose, the utility model discloses a technical scheme as follows:

the utility model provides a full shielding structure of electret microphone, includes the circuit board body, the circuit board body is connected with the bulge, be equipped with the lead-out wire on the bulge.

As a preferable technical scheme, the device further comprises a shell with an opening at one end, and a notch matched with the size of the protruding part is arranged at the opening end of the shell.

In a preferred embodiment, the circuit board main body has a disk shape.

As a preferable technical scheme, two end faces of the circuit board body are respectively set as a front face and a back face, and metal foils are arranged on the front face and the back face.

As a preferred technical solution, the protruding portion has an upper end surface and a lower end surface, the upper end surface is flush with the front surface, and the lower end surface is flush with the back surface.

As a preferable technical solution, the outgoing line is provided on the upper end face.

As a preferred technical scheme, the reverse side is provided with blind holes.

As a preferred technical solution, there are two blind holes.

In a preferred embodiment, the metal foil is a copper foil.

As a preferable technical scheme, the number of the outgoing lines is two, one outgoing line is an output end, and the other outgoing line is a ground end.

The utility model has the advantages of that:

the utility model discloses a protrusion is located on this external bulge of circuit board to the lead-out wire for the metal forming in the one side of circuit board body can remain completely, and when circuit board body and shell cooperation, circuit board body and shell can constitute a complete confined metal shielding casing, thereby can effectually resist the interference signal who shields outside each frequency channel.

Drawings

Fig. 1 is a schematic structural diagram of a circuit board body in a full-shielding structure of an electret microphone according to the present invention;

FIG. 2 is a schematic view of the reverse side of FIG. 1;

fig. 3 is a schematic structural diagram of a housing in a full-shielding structure of an electret microphone of the present invention.

In the figure: 1-circuit board body, 11-bulge, 12-leading-out wire, 13-blind hole, 2-shell and 21-notch.

Detailed Description

In order to facilitate understanding for those skilled in the art, the present invention will be further described with reference to the accompanying drawings.

Please refer to fig. 1, which is an embodiment of a full shielding structure of an electret microphone of the present invention, including a circuit board body 1, wherein the circuit board body 1 is connected to a protrusion 11, the protrusion 11 is provided with an outgoing line 12, the outgoing line 12 is located outside the circuit board body 1, and the outgoing line 12 can output an acoustic signal.

Note that, in actual production, the lead-out wires 12 are usually made in the form of pads.

In this embodiment, please refer to fig. 3, the present invention further includes a housing 2 with an opening at one end, the opening end of the housing 2 is matched with the size of the circuit board body 1, and when the circuit board body 1 is matched with the housing 2, the two can form a complete and closed metal shielding shell; further, the opening end of the housing 2 can be provided with a notch 21 matched with the size of the protrusion 11, so that the circuit board body 1 and the housing 2 can be conveniently mounted, and the protrusion 11 and the notch 21 can be used for effectively positioning the circuit board body 1 on the housing 2.

It should be noted that, the conventional electret microphone is generally cylindrical, and for convenience of production and installation, the circuit board body 1 is preferably disc-shaped, and correspondingly, the housing 2 may be cylindrical with an opening at one end, and when the circuit board body 1 is installed on the housing 2, one surface of the circuit board body 1 located outside is a front surface, and one surface located inside is a back surface; by arranging the metal foils on the front side and the back side of the circuit board body 1, external interference signals can be effectively shielded and isolated, and further, the metal foils are preferably copper foils.

In the present embodiment, referring to fig. 1, the protruding portion 11 is preferably formed by "extending" along the front and back surfaces of the circuit board body 1, which is convenient for both production and installation and storage; in practical production, the protrusion 11 and the disc-shaped circuit board body 1 can be connected by adhesion, or they can be produced by integral molding.

On the basis of the above embodiment, referring to fig. 1, the outgoing line 12 is preferably located on one side of the front surface of the circuit board body 1, so that after the circuit board body 1 is matched with the housing 2, the outgoing line 12 is located outside, and subsequent wiring is facilitated.

Since the sensitivity and the frequency response of the electret microphone are related to the vibration amplitude of the vibration film, in actual use, the larger the space on the back surface of the vibration film, the easier the sensitivity is to be improved, and the magnitude of the vibration amplitude of the vibration film has a correlation with the frequency response characteristic thereof. In this embodiment, referring to fig. 2, by providing the blind hole 13 on the reverse side of the circuit board body 1, a flow channel between an internal cavity formed by the circuit board body 1 and the housing 2 and other small spaces can be increased or opened to some extent, and the vibration resistance of the vibration film is partially released, so that the vibration amplitude of the vibration film is increased, and the sensitivity of the electret microphone is also improved; in actual production, the number and the positions of the blind holes 13 are set according to the specific internal structure of the electret microphone, so as to ensure that a flow channel can be effectively formed; preferably, two blind holes 13 are provided.

In this embodiment, referring to fig. 1, a drain output connection mode is adopted, two outgoing lines 12 are provided, one outgoing line 12 is an output end, and the other outgoing line 12 is a ground end; in another embodiment, if a source output connection form is adopted, three lead lines 12 may be provided.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. The utility model provides a full shielding structure of electret microphone, characterized by, includes the circuit board body, the circuit board body is connected with the bulge, be equipped with the lead-out wire on the bulge.

2. The full shield structure of claim 1, further comprising a housing with an opening at one end, wherein the opening end of the housing is provided with a notch matching the size of the protrusion.

3. The full shield structure of claim 1, wherein the circuit board body is formed in a disc shape.

4. The full-shielding structure of the electret microphone as claimed in claim 3, wherein two end faces of the circuit board body are respectively a front face and a back face, and the front face and the back face are respectively provided with metal foils.

5. The full shield structure of claim 4, wherein said protrusion has an upper end and a lower end, said upper end being flush with said front surface and said lower end being flush with said back surface.

6. The full shield structure of claim 5, wherein said outgoing line is disposed on said upper end surface.

7. The full shielding structure of the electret microphone as claimed in claim 4, wherein the reverse side has blind holes.

8. The full shield structure of claim 7, wherein there are two blind holes.

9. The full shield structure for an electret microphone of claim 4, wherein said metal foil is a copper foil.

10. The full-shielding structure of the electret microphone as claimed in claim 1 or 5, wherein the number of the outgoing lines is two, one outgoing line is an output terminal, and the other outgoing line is a ground terminal.