WO2019103206A1

WO2019103206A1 - Directional microphone

Info

Publication number: WO2019103206A1
Application number: PCT/KR2017/013573
Authority: WO
Inventors: 박두영
Original assignee: 주식회사 파트론
Priority date: 2017-11-24
Filing date: 2017-11-27
Publication date: 2019-05-31

Abstract

A directional microphone of the present invention comprises a substrate, a first housing, a second housing, a MEMS transducer, and a signal processing element. In an embodiment of the present invention, the substrate may include a first acoustic hole, the first housing may include a second acoustic hole, and the second housing may include a third acoustic hole.

Description

Directional microphone

The present invention relates to a microphone, and more particularly, to a directional MEMS microphone including a MEMS transducer element and having a directional acoustic characteristic.

2. Description of the Related Art In recent years, electronic devices such as mobile communication terminals such as mobile phones and smart phones, tablet PCs, and MP3 players have become smaller. As a result, parts of electronic devices are becoming smaller. Therefore, development of a MEMS (Micro Electro Mechanical System) technology capable of solving physical limitations of parts is underway.

MEMS technology can be applied to micro-scale micro-sensors, actuators, or electromechanical structures using micro-machining techniques based on integrated circuit technology. The MEMS microphone with such a MEMS technology not only can realize a very small device, but also can manufacture a large number of MEMS microphones on one wafer, thereby enabling mass production.

A variety of techniques for such MEMS microphones are known. For example, Korean Patent Laid-Open Publication No. 10-2007-0053763 (published May 25, 2007) entitled " Silicon condenser microphone and its manufacturing method ", Korean Patent Publication No. 10-2007-0078391 July 31, 2010), and a microphone of Korean Patent Laid-Open No. 10-0971293 (published on July 13, 2010).

Korean Patent Publication No. 10-2007-0053763 (published on May 25, 2007)

Korean Patent Publication No. 10-2007-0078391 (Disclosure Date: July 31, 2007)

Korean Patent Publication No. 10-0971293 (Published on July 13, 2010)

A problem to be solved by the present invention is to provide a microphone having a directivity characteristic.

Another object to be solved by the present invention is to provide a directional microphone capable of easily adjusting the directivity characteristic of a microphone.

According to an aspect of the present invention, there is provided a directional microphone including a substrate, a first housing, a second housing, a MEMS transducer, and a signal processing element.

In one embodiment of the present invention, the substrate includes a first acoustic hole, the first housing includes a second acoustic hole, and the second housing may include a third acoustic hole.

In one embodiment of the invention, it may further comprise a delay unit.

The directional microphone according to an embodiment of the present invention has a directivity characteristic and has a merit that it can detect the sound more clearly.

Further, the directional microphone according to an embodiment of the present invention has an advantage that directivity characteristics can be easily adjusted.

1 is a perspective view of a directional microphone according to an embodiment of the present invention.

2 is a perspective view of a directional microphone according to one embodiment of the present invention, as viewed from below.

3 is a cross-sectional view taken along line A-A in Fig.

4 is an exemplary cross-sectional view of the MEMS transducer shown in FIG.

5 and 6 are use state diagrams of a directional microphone according to an embodiment of the present invention.

7 is a cross-sectional view of a directional microphone according to another embodiment of the present invention.

8 and 9 are sectional views of a directional microphone according to another embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In describing the present invention, if it is judged that it is possible to make the gist of the present invention obscure by adding a detailed description of a technique or configuration already known in the field, it is omitted from the detailed description. In addition, terms used in the present specification are terms used to appropriately express the embodiments of the present invention, which may vary depending on the person or custom in the relevant field. Therefore, the definitions of these terms should be based on the contents throughout this specification.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. The singular forms as used herein include plural forms as long as the phrases do not expressly express the opposite meaning thereto. As used herein, the meaning of "comprising" embodies certain features, areas, integers, steps, operations, elements and / or components, And the like.

Hereinafter, a directional microphone according to an embodiment of the present invention will be described with reference to FIGS. 1 to 6 attached hereto.

1 is a perspective view of a directional microphone according to an embodiment of the present invention. 2 is a perspective view of a directional microphone according to one embodiment of the present invention, as viewed from below. 3 is a cross-sectional view taken along line A-A in Fig. 4 is an exemplary cross-sectional view of the MEMS transducer shown in FIG. 5 and 6 are use state diagrams of a directional microphone according to an embodiment of the present invention.

1 to 3, a directional microphone according to an embodiment of the present invention includes a substrate 100, a first housing 200, a second housing 300, a MEMS transducer 400, and a signal processing element (not shown) 500).

The substrate 100 is formed in the form of a plate, which is a lower part of the directional microphone of the present invention. The substrate 100 may be formed of a printed circuit board (PCB). The substrate 100 may be specifically formed of a rigid printed circuit board, a semiconductor substrate, a ceramic substrate, or the like.

The substrate 100 includes a first acoustic hole 110. The first acoustic hole 110 is formed to penetrate through the lower portion from the upper portion of the substrate 100. Specifically, the first acoustic hole 110 may be formed to penetrate the substrate 100 in a direction perpendicular to the upper surface or the lower surface of the substrate 100. Although the first acoustic holes 110 are shown as being formed in a single hole shape in FIGS. 1 to 3, in some cases, the plurality of holes may be located closely.

A MEMS transducer 400 and a signal processing element 500 to be described later are mounted on the upper surface of the substrate 100. The substrate 100 is coupled with a first housing 200 to be described later to form a first internal space S1.

The first housing 200 is formed to cover the substrate 100. Specifically, the first housing 200 is formed in a bottom open state, and the bottom is coupled to be covered by the substrate 100. The first inner space S1 is formed by the combination of the substrate 100 and the first housing 200. [ More specifically, the first housing 200 includes an upper surface facing away from the substrate 100, and a side bent downwardly from a rim portion of the upper surface. The lower side of the side surface can be coupled with the substrate 100.

The first housing 200 may be connected to the substrate 100 through a solder 150 or the like. Although not shown in the drawing, a ground portion having a ground potential is formed on the substrate 100, and the first housing 200 may be electrically connected to the ground portion of the substrate 100 to be coupled.

The first housing 200 may be a can made of a metal material, for example. However, the present invention is not limited thereto, and may be formed of the same material as the plastic injection molded article or the substrate 100, as the case may be.

The first housing 200 includes a second acoustic hole 210. The second acoustic hole 210 is formed to penetrate the upper surface of the first housing 200. Although the second acoustic holes 210 are shown as being formed in a single hole shape in FIGS. 1 to 3, in some cases, the plurality of holes may be located closely.

The second housing 300 is formed to cover the upper surface of the first housing 200. Specifically, the second housing 300 is formed with the lower surface opened, and the lower portion is coupled to cover the first housing 200. More specifically, the second housing 300 can be coupled such that the lower portion thereof is covered by the upper surface of the first housing 200. The second inner space S2 is formed by the engagement of the first housing 200 and the second housing 300. [

The second housing 300 includes an upper surface facing away from the upper surface of the first housing 200 and a lower surface extending downward from the upper surface of the upper surface. The lower end of the side surface of the second housing 300 can be engaged with the first housing 200.

The second housing 300 may be connected to the first housing 200 through a solder 250 or the like. As described above, the first housing 200 can be electrically connected to the grounding portion of the substrate 100, and the second housing 300 can be electrically connected to the first housing 200 again. As a result, both the first housing 200 and the second housing 300 can have a ground potential, which improves the electrical stability of the directional microphone of the present invention, and reduces the influence of EMI noise introduced from the outside Can be reduced.

The second housing 300 may be of a can type, for example, made of a metal material or the like. However, the present invention is not limited thereto, and may be formed of the same material as the plastic injection molded article or the substrate 100, as the case may be.

The second housing 300 includes a third acoustic hole 310. The third acoustic hole 310 is formed to penetrate through the second housing 300. Although the third acoustic holes 310 are illustrated as being formed on the upper surface of the second housing 300 in FIGS. 1 to 3, the third acoustic holes 310 may be formed on the upper surface of the second microphone 300 to control the directivity characteristic of the directional microphone of the present invention. It can also be located on the side. Also, although the third acoustic holes 310 are shown as being formed in a single hole shape in FIGS. 1 to 3, in some cases, the plurality of holes may be located closely.

The MEMS transducer 400 is an element that converts a sound signal into an electric signal. The MEMS transducer 400 is mounted on the substrate 100 and accommodated in the first internal space S1 formed by the substrate 100 and the first housing 200. [ In addition, the MEMS transducer 400 may be electrically connected to the substrate 100 or the signal processing device 500 through a wire 450 or the like. The MEMS transducer (400) provides the converted electrical signal to the signal processing element (500).

The configuration of the MEMS transducer 400 will be described in detail with reference to FIG. Referring to FIG. 4, the MEMS transducer 400 may include a body 149, a back plate 146, and a diaphragm 148. When the back plate 146 and the diaphragm 148 are spaced apart from each other (that is, a cavity is located between the back plate 146 and the diaphragm 148) and the diaphragm 148 is vibrated by the negative pressure, And the capacitance with the plate 146 is measured to sense the acoustic signal. Although the back plate 146 is shown above the diaphragm 148 in the figure, it is not limited thereto. That is, the back plate 146 may be disposed below the diaphragm 148.

The signal processing element 500 amplifies the electric signal transmitted from the MEMS transducer 400. The signal processing device 500 may be, for example, an application-specific integrated circuit (ASIC), but is not limited thereto. The signal processing device 500 may be fixed to the upper surface of the substrate 100 by die bonding or wire bonding.

5 to 6, the directional characteristics of a directional microphone according to an embodiment of the present invention will be described.

Referring to FIG. 5, the directional microphone according to an embodiment of the present invention forms a first acoustic path P1 and a second acoustic path P2.

The first acoustic path P1 is a path from the bottom of the substrate 100 to the MEMS transducer 400 through the first acoustic hole 110. [

The second acoustic path P 2 is a path through the third acoustic hole 310 and the second acoustic hole 210 sequentially from the outside of the second housing 300 to the MEMS transducer 400. The first acoustic path P1 follows the bottom of the MEMS transducer 400 and the second acoustic path P2 follows the top of the MEMS transducer 400. [

The second acoustic path P2 may be changed depending on the positions of the second acoustic hole 210 and the third acoustic hole 310. [ Specifically, when the second acoustic hole 210 and the third acoustic hole 310 overlap with each other in the vertical direction, the second acoustic path P2 can be relatively shortened. However, as shown in FIG. 5, when the second acoustic hole 210 and the third acoustic hole 310 are positioned to be offset from each other in the vertical direction, the second acoustic path P2 can be relatively extended.

The directional microphone according to an embodiment of the present invention corresponds to a rear type that receives sound from a lower portion of the substrate 100 to a microphone as a main reception sound. Therefore, the lower direction of the substrate 100 of the microphone is referred to as forward, and the opposite direction is referred to as a rearward direction. In the microphone of the present invention, the sound generated in the front corresponds to the main sound, and the MEMS transducer 400 smoothly receives the sound. However, the sound generated from the backside corresponds to noise and should be removed from the MEMS transducer 400 so as not to affect the reception of the main sound generated in the front.

Although not shown in the drawings, the directional microphone of the present invention may be a front type that receives sound from the upper portion of the substrate 100 to the microphone through a main receiving sound.

6, the noise generated from the rear can reach the MEMS transducer 400 through the first acoustic path P1 and reach the MEMS transducer 400 through the second acoustic path P2. can do. At this time, a first time T1 at which the noise sound reaches the MEMS transducer 400 through the first acoustic path P1 and a second time T2 at which the acoustic sound reaches the MEMS transducer 400 through the second acoustic path P2 The two times T2 may be equal to each other. Here, the first time T1 and the second time T2 are equal to each other, and the first time T1 and the second time T2 are completely equal to each other, and the error includes an error that can occur in a manufacturing process. This is because, when the noise sound travels through the second acoustic path P2, the progress of the noise sound is delayed while passing through the second inner space S2. The passage of the noise sound through the second internal space S2 produces an effect similar to that through a delay unit formed of the same material as the micro-perforated plate.

As such, if the first time T1 and the second time T2 are the same, the noise sound reaches the MEMS transducer 400 through the first acoustic path P1 and the noise sound reaches the second acoustic path < RTI ID = P2 to the MEMS transducer 400 affects the diaphragm of the MEMS transducer 400 at the same time. Therefore, the two sounds propagated through different paths interfere with each other, and the MEMS transducer 400 is hardly affected by the noise signal S1. Therefore, the MEMS transducer 400 recognizes only the main acoustic signal generated in front, and does not recognize the noise signal. In this way, a unidirectional characteristic can be realized.

The extent to which the progress of the noise sound is delayed can be adjusted by adjusting the size and shape of the second housing 300, the position and size of the third acoustic hole 310, and the like. As a result, the degree of attenuation of noise or the direction of noise can be adjusted.

Hereinafter, a directional microphone according to another embodiment of the present invention will be described with reference to FIG.

7 is a cross-sectional view of a directional microphone according to another embodiment of the present invention. For convenience of explanation, the differences from those described in Figs. 1 to 6 will be mainly described.

Referring to FIG. 7, the directional microphone of the present embodiment further includes a delay unit 600. The delay unit 600 may be located inside the first housing 200 and / or the second housing 300. 7, the delay unit 600 is positioned so as to cover the inside of the second housing 300, particularly, the third acoustic hole 310, but the position of the delay unit 600 is not limited thereto.

The delay unit 600 serves to delay the acoustic signal coming through the second acoustic path P2. The delay unit 600 may be a plate including micro-perforations. The plate may be, for example, a metal or a semiconductor such as silicon. The metal or silicon has a relatively high heat-resistant temperature, and can easily withstand the operating temperature of the MEMS microphone.

Also, the plate may have one or more micropores. Depending on the number of micro-perforations or the size of the micro-perforations, the degree of delay of the delay unit 600 can be adjusted. That is, if the number of microperforations is large and the size is large, the degree of delay is small. Conversely, if the number of microperforations is small and the size is small, the degree of delay is large.

As described above, the acoustic signal arriving at the MEMS transducer 400 through the second acoustic path P2 is delayed while passing through the second inner space S2, and the degree of delay by the delay unit 600 is . Optionally, the delay unit 600 may be added to reduce the size of the second internal space S2, which may contribute to downsizing the overall size of the directional microphone of the present invention.

Hereinafter, a directional microphone according to another embodiment of the present invention will be described with reference to FIGS. 8 and 9. FIG.

8 and 9 are sectional views of a directional microphone according to another embodiment of the present invention. For convenience of explanation, the differences from those described in Figs. 1 to 6 will be mainly described.

Referring to FIG. 10, a third acoustic hole 310 may be formed on a side surface of the second housing 300. Referring to FIG. 11, a plurality of third acoustic holes 310 may be spaced apart from each other. One of the plurality of third acoustic holes 310 spaced apart from each other may be formed on the upper surface of the second housing 300 and the other may be formed on the side surface.

The length of the second acoustic path P 2 can be adjusted by adjusting the position of the third acoustic hole 310. Therefore, the attenuation characteristics of the noise signal and the direction of the noise signal can be adjusted.

The embodiments of the directional microphone of the present invention have been described above. The present invention is not limited to the above-described embodiments and the accompanying drawings, and various modifications and changes may be made by those skilled in the art to which the present invention pertains. Accordingly, the scope of the present invention should be determined not only by the claims of the present specification, but also by equivalents to the claims.

100: substrate 110: first acoustic hole

200: first housing 210: second acoustic hole

300: second housing 310: third acoustic hole

400: MEMS transducer 500: signal processing element

Claims

A substrate on which a first acoustic hole is formed;

A first housing coupled to the substrate to form a first inner space and having a second acoustic hole formed on an upper surface thereof facing the substrate;

A second housing coupled to the second housing to form a second inner space, and a third acoustic hole formed therein;

A MEMS transducer mounted on the substrate and positioned to cover the first acoustic hole in the first internal space; And

And a signal processing element mounted on the substrate and disposed in the first internal space to process electrical signals converted by the MEMS transducer.
The method according to claim 1,

And the third acoustic hole is formed on the upper surface of the second housing opposite to the upper surface of the first housing.
The method according to claim 1,

And the first internal space is sealed at portions other than the second acoustic hole.
The method according to claim 1,

And the second internal space is sealed in portions other than the second acoustic hole and the third acoustic hole.