Microphone chip, micro-electro-mechanical system microphone, and terminal device

Abstract

The present invention provides a microphone chip, a micro-electro-mechanical system microphone, and a terminal device. The microphone chip comprises a base, a back plate fixed to the base, and a diaphragm electrode arranged opposite to and spaced apart from the back plate in a first direction; a back plate electrode is arranged on the side of the back plate facing the diaphragm electrode; the back plate electrode comprises a plurality of first electrode plates; the diaphragm electrode comprises a plurality of second electrode plates and a center column; the center column is arranged in parallel to the first direction; the plurality of first electrode plates are arranged around the center column at intervals; the plurality of second electrode plates are arranged around the center column at intervals and are flexibly connected to the center column; each first electrode plate is electrically conductive, and the plurality of second electrode plates are electrically conductive at intervals; or each second electrode plate is electrically conductive, and the plurality of first electrode plates are electrically conductive at intervals. Compared with the prior art, the microphone chip, the micro-electro-mechanical system microphone, and the terminal device provided by the present invention aim to realize miniaturization of the microphone and also achieve a sound direction determining function.

Description

Microphone chips, micro-electromechanical microphones and terminal equipment Technical Field

[0001] The present invention relates to the field of microphone technology, and in particular to a microphone chip, a micro-electromechanical microphone, and a terminal device. Background Art

[0002] A traditional MEMS microphone consists of a backplate and a diaphragm at a certain distance from the backplate. It detects sound by generating changes in the capacitance between the diaphragm and the backplate through pressure waves acting on the diaphragm, thereby converting the sound signal into an electrical signal. This type of microphone is omnidirectional and it is difficult to pick up the pure sound we want from noisy sounds. To achieve directionality, a microphone array must be used. Directional microphones currently only exist in professional sound ranges or large packages that have a great impact on signal quality.

[0003] Therefore, in order to enable the miniaturized MEMS microphone to have the sound localization function, it is necessary to improve the structure. Summary of the Invention

[0004] The purpose of the present invention is to overcome the above technical problems and provide a microphone chip, a micro-electromechanical microphone and a terminal device that can be miniaturized and have a sound directional function.

[0005] In order to achieve the above-mentioned objectives, an embodiment of the present invention provides a microphone chip, comprising a substrate, a back plate fixed on the substrate, and a diaphragm electrode arranged relative to the back plate along a first direction, a back plate electrode is provided on the side of the back plate facing the diaphragm electrode, the back plate electrode comprises a plurality of first electrode plates, the diaphragm electrode comprises a plurality of second electrode plates and a central column, the central column is arranged parallel to the first direction, the first electrode plates are arranged at intervals around the central column, the second electrode plates are arranged at intervals around the central column and are flexibly connected to the central column; each first electrode plate is conductive, and the plurality of second electrode plates are conductive at intervals; or, each second electrode plate is conductive, and the plurality of first electrode plates are conductive at intervals.

[0006] According to an embodiment of the first aspect of the present invention, the central post is an insulator and is connected to the back plate.

[0007] According to an embodiment of the first aspect of the present invention, the central column is a conductor, and the diaphragm electrode further includes a connector disposed at an end of the central column away from the back plate, with both ends of the connector respectively connecting the central column and the substrate.

[0008] According to an embodiment of the first aspect of the present invention, the diaphragm electrode further includes a fixing member disposed at an end of each second electrode plate away from the central column, and two ends of the fixing member are respectively connected to the second electrode plate and the substrate.

[0009] According to an embodiment of the first aspect of the present invention, the fixing member includes a main body portion arranged in a direction surrounding the central column, a first fixed end formed by bending and extending from one end of the main body portion toward a direction close to the central column, and a second fixed end formed by bending and extending from the other end of the main body portion toward a direction away from the central column; the first fixed end is connected to the second electrode plate, and the second fixed end is connected to the base.

[0010] According to an embodiment of the first aspect of the present invention, along the direction in which the plurality of second electrode plates are spaced apart, the distances between the two ends of each second electrode plate and the first electrode plate are different.

[0011] According to an embodiment of the first aspect of the present invention, a projection of a first electrode plate along the first direction onto the second electrode plates falls on the two second electrode plates.

[0012] According to an embodiment of the first aspect of the present invention, multiple first electrode plates are connected to the back plate, and the microphone chip also includes multiple sound holes that penetrate the back plate and each first electrode plate along the first direction, and the projection of each sound hole along the first direction to the second electrode plate falls on the second electrode plate.

[0013] An embodiment of the present invention also provides a micro-electromechanical microphone, comprising a cover body having a receiving space and a microphone chip provided in any of the aforementioned embodiments, the cover body comprising a first connecting hole and a second connecting hole, both of which are used to connect the receiving space with the outside world; the microphone chip is received in the receiving space, and the base is connected to the cover body and covers the first connecting hole.

[0014] An embodiment of the present invention further provides a terminal device, comprising the micro-electromechanical microphone provided by any of the aforementioned embodiments.

[0015] Compared with the related art, the microphone chip, micro-electromechanical microphone and terminal device provided by the present invention are configured such that a backplate electrode includes multiple first electrode plates, a diaphragm electrode includes multiple second electrode plates and a central column, the central column is configured parallel to the first direction, multiple first electrode plates are configured to be spaced apart around the central column, multiple second electrode plates are configured to be spaced apart around the central column and are flexibly connected to the central column, so that a capacitor structure is formed between the first electrode plate and the second electrode plate, and when the airflow generated by sounds from all directions of the outside world acts on different second electrode plates, twisting can occur between the second electrode plate and the central column. At the same time, since the multiple first electrode plates are conductive and the multiple second electrode plates are conductive at intervals; or, the multiple second electrode plates are conductive and the multiple first electrode plates are conductive at intervals, the twisting of the aforementioned second electrode plates can be converted into a change in capacitance, so that the microphone chip can judge the source direction of the sound by the direction of the change in capacitance, thereby having a sound directional function. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. Those skilled in the art can also derive other drawings based on these drawings without inventive work, among which:

[0017] FIG1 is a schematic diagram of the three-dimensional structure of a microphone chip according to an embodiment of the present invention;

[0018] FIG2 is a schematic cross-sectional view of the microphone chip provided in FIG1 of the present invention;

[0019] FIG3 is a schematic structural diagram of a first electrode plate and a second electrode plate in a microphone chip according to an embodiment of the present invention;

[0020] FIG4 is a structural diagram of another embodiment of a fixing method for the second electrode plate in the microphone chip provided by the present invention;

[0021] FIG5 is a schematic structural diagram of another embodiment of a fixing method for the second electrode plate in the microphone chip provided by the present invention;

[0022] FIG6 is a schematic structural diagram of an embodiment of a micro-electromechanical microphone provided by the present invention. DETAILED DESCRIPTION

[0023] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0024] As shown in Figures 1 to 5, an embodiment of the present invention provides a microphone chip 100, including a substrate 10, a back plate 20 fixed on the substrate 10, and a diaphragm electrode 30 arranged relative to the back plate 20 along a first direction X. A back plate electrode 21 is provided on the side of the back plate 20 facing the diaphragm electrode 30, the back plate electrode 21 includes a plurality of first electrode plates 211, and the diaphragm electrode 30 includes a plurality of second electrode plates 31 and a center column 32.

[0025] The backplate 20 is fixed to the substrate 10 , which means that the backplate 20 and the substrate 10 can be connected by physical vapor deposition methods such as evaporation or sputtering to strengthen the connection strength between the substrate 10 and the backplate 20 and improve the structural consistency of the substrate 10 and the backplate 20 .

[0026] In these embodiments of the present application, after the back plate 20 and the base 10 are fixed, a semi-enclosed structure with a back cavity 101 is formed. The aforementioned diaphragm electrode 30 and the back plate electrode 21 are both accommodated in the back cavity 101 to provide a stable and relatively sealed working environment for the diaphragm electrode 30 and the back plate electrode 21.

[0027] A backplate electrode 21 is provided on the side of the backplate 20 facing the diaphragm electrode 30, which means that in these embodiments of the present application, the diaphragm electrode 30 and the backplate electrode 21 are arranged relative to each other along the first direction X, so as to form a capacitor structure using the diaphragm electrode 30 and the backplate electrode 21. During the operation of the microphone chip 100, when the airflow generated by the vibration of sound in the air acts on the diaphragm electrode 30, the relative position relationship between the diaphragm electrode 30 and the backplate electrode 21 changes, thereby causing the capacitance and current between the two to change, thereby converting the sound signal into an electrical signal.

[0028] The back plate electrode 21 includes multiple first electrode plates 211, and the diaphragm electrode 30 includes multiple second electrode plates 31 and a central column 32. The central column 32 is arranged parallel to the first direction X. The first electrode plates 211 are arranged at intervals around the central column 32, and the second electrode plates 31 are arranged at intervals around the central column 32 and are flexibly connected to the central column 32; each first electrode plate 211 is conductive, and the multiple second electrode plates 31 are conductive at intervals; or, each second electrode plate 31 is conductive, and the multiple first electrode plates 211 are conductive at intervals.

[0029] The backplate electrode 21 and the diaphragm electrode 30 together form components within the microphone chip 100 for converting external sound signals into electrical signals. The backplate electrode 21 includes multiple first electrode plates 211, and the diaphragm electrode 30 includes multiple second electrode plates 31 and a center post 32. The first and second electrode plates 211 and 31 can be spaced apart along a first direction X, generating capacitance between the first and second electrode plates 211 and 31.

[0030] Each second electrode plate 31 is flexibly connected to the central column 32, meaning that after being connected to the central column 32, each second electrode plate 31 can be twisted by external airflow. For example, in some embodiments, the second electrode plates 31 can be flexible. Thus, when external airflow acts on the second electrode plates 31, the second electrode plates 31 can be slightly twisted around their connection points with the central column 32.

[0031] In some embodiments of the present application, multiple second electrode plates 31 can be arranged in a direction in which they are spaced apart, and the distances between the two ends of each second electrode plate 31 and the first electrode plate 211 are different. A possible implementation method is that each second electrode plate 31 itself is bent with a certain curvature so that the distances between the two ends of the second electrode plate 31 and the first electrode plate 211 along the direction in which they are spaced apart are different, and there is an angle between each second electrode plate 31 and the plane where the first electrode plate 211 is located.

[0032] Alternatively, in some embodiments of the present invention, multiple first electrode plates 211 may be parallel to each other, multiple second electrode plates 31 may be parallel to each other, and the plane where each second electrode plate 31 is located may have an angle with the plane where the first electrode plate 211 is located.

[0033] In this way, since there is an angle between the plane where each second electrode plate 31 is located and the plane where the first electrode plate 211 is located, the second electrode plate 31 is more likely to twist when affected by external airflow, thereby improving the sensitivity of the second electrode plate 31 to sensing external airflow.

[0034] At the same time, since the first electrode plates 211 are arranged at intervals around the central column 32, and the second electrode plates 31 are arranged at intervals around the central column 32 and are flexibly connected to the central column 32, the first electrode plates 211 arranged at intervals around the central column 32 can be used to sense the capacitance changes in various directions of the second electrode plates 31 when they are twisted by the external airflow, and then the direction of the sound transmitted to the microphone chip 100 can be judged.

[0035] For example, in some embodiments of the present application, each first electrode plate 211 disposed at intervals can be configured as an electrode plate for outputting current to the outside, and each first electrode plate 211 can be used to sense the capacitance change between the corresponding position and the second electrode plate 31. When the second electrode plate 31 is twisted under the action of the airflow generated by external sound, the area facing the second electrode plate 31 and the first electrode plate 211 opposite to it along the first direction X will change, thereby changing the capacitance between the two, so that the first electrode plate 211 at this position can achieve directional recognition of sound by sensing the capacitance change. In some embodiments, each second electrode plate 31 can also be configured to output current to the outside, and this application does not limit this.

[0036] Each first electrode plate 211 is conductive, and the plurality of second electrode plates 31 are conductive at intervals; or, the plurality of second electrode plates 31 are conductive, and the plurality of first electrode plates 211 are conductive at intervals. These refer to two embodiments of the present invention. In the embodiment in which each first electrode plate 211 is conductive, and the plurality of second electrode plates 31 are conductive at intervals, when external airflow acts on a second electrode plate 31, the twisting of the second electrode plate 31 can change the area of ​​direct contact between the second electrode plate 31 and the first electrode plate 211, thereby causing a change in capacitance between the two. Similarly, in the embodiment in which each second electrode plate 31 is conductive, and the plurality of first electrode plates 211 are conductive at intervals, the twisting of the second electrode plate 31 can also change the area of ​​direct contact between the second electrode plate 31 and the first electrode plate 211, thereby causing a change in capacitance between the two. In this way, the direction of the external airflow can be determined based on the direction of the first electrode plate 211 or the second electrode plate 31 in the microphone chip 100 whose capacitance changes, thereby achieving a sound directional function of the microphone chip 100.

[0037] It should be noted that in these embodiments of the present application, the conductivity or non-conductivity of the first electrode plate 211 and the second electrode plate 31 can be achieved by whether the first electrode plate 211 and the second electrode plate 31 are doped. In other words, in an embodiment where each first electrode plate 211 is conductive and the plurality of second electrode plates 31 are conductive at intervals, each first electrode plate 211 can be doped, and the plurality of second electrode plates 31 can be doped at intervals. The configurations of other embodiments are similar and will not be described in detail here.

[0038] Regarding the setting method of the second electrode plate 31, in some embodiments of the present invention, the central column 32 can be set as an insulator and connected to the back plate 20. In these embodiments, multiple first electrode plates 211 can be set as the aforementioned conductive ones, and multiple second electrode plates 31 can be set to be conductive at intervals to realize the sound directional function of the aforementioned microphone chip 100.

[0039] In some embodiments of the present invention, the center column 32 can also be set as a conductor, and the diaphragm electrode 30 also includes a connector 33 arranged at the end of the center column 32 away from the back plate 20, and the two ends of the connector 33 are respectively connected to the center column 32 and the substrate 10. In these embodiments, multiple second electrode plates 31 can be set to be conductive, and multiple first electrode plates 211 can be conductive at intervals to realize the sound directional function of the aforementioned microphone chip 100.

[0040] In some embodiments of the present invention, the diaphragm electrode 30 may further include a fixing member 34 disposed at an end of each second electrode plate 31 facing away from the central column 32, with the two ends of the fixing member 34 respectively connecting the second electrode plate 31 to the substrate 10. In these embodiments, the size of the central column 32 in the first direction X can be reduced, and the fixing member 34 can be used to connect each second electrode plate 31 to the substrate 10. Furthermore, the aforementioned configuration of the plurality of first electrode plates 211 being conductive and the plurality of second electrode plates 31 being conductive at intervals, or the configuration of the plurality of second electrode plates 31 being conductive and the plurality of first electrode plates 211 being conductive at intervals, can both achieve the sound directional function of the aforementioned microphone chip 100.

[0041] In some embodiments of the present invention, a fixing member 34 may further include a main body 341 extending in a direction surrounding the central column 32, a first fixing end 342 extending and bending from one end of the main body 341 toward the central column 32, and a second fixing end 343 extending and bending from the other end of the main body 341 away from the central column 32. The first fixing end 342 is connected to the second electrode plate 31, and the second fixing end 343 is connected to the substrate 10. Specifically, the main body 341 is an annular segment extending in a direction surrounding the central column 32, and together with the first fixing end 342 and the second fixing end 343, forms a structure similar to the letter "Z" (Z). This reduces the connection area between the fixing member 34 and the second electrode plate 31, making it less difficult for the fixing member 34 to twist the second electrode plate 31 under the influence of external airflow, thereby further improving the sensitivity of the microphone chip 100 to external airflow.

[0042] In some embodiments of the present invention, a plurality of first electrode plates 211 may be provided and connected to the back plate 20 . The microphone chip 100 further includes a plurality of sound holes 40 passing through the back plate 20 and each first electrode plate 211 along the first direction X. The projection of each sound hole 40 along the first direction X onto the second electrode plate 31 falls on the second electrode plate 31 .

[0043] The plurality of first electrode plates 211 are connected to the back plate 20 . A possible implementation is to form a first electrode plate layer by deposition, etch the first electrode plate layer to form the plurality of first electrode plates 211 , and then deposit the back plate 20 on the plurality of first electrode plates 211 .

[0044] Multiple sound holes 40 extend through the back plate 20 and each first electrode plate 211 along the first direction X, matching the opening at the end of the base 10 facing away from the back plate 20. This allows airflow generated by external sound to flow into the back cavity 101 through the sound holes 40 and out through the openings, improving the smoothness of airflow within the back cavity 101 and further increasing the sensitivity of the second electrode plate 31 to airflow generated by external sound. In some embodiments, airflow generated by external sound can also flow into the back cavity 101 through the openings and out through the sound holes 40. This arrangement also achieves the aforementioned effect of locating the direction of sound.

[0045] In some embodiments of the present invention, a projection of a first electrode plate 211 along the first direction X onto the second electrode plate 31 may be arranged to fall on two second electrode plates 31, that is, multiple first electrode plates 211 and multiple second electrode plates 31 are staggered in the first direction X. In this way, the airflow can act more on the edge portion of the second electrode plate 31, making the second electrode plate 31 more likely to twist when impacted by external airflow, thereby further improving the sensing sensitivity of the second electrode plate 31 to external airflow.

[0046] Since there is a certain interval between adjacent first electrode plates 211, acoustic holes 40 will not be set at these positions. In these embodiments of the present invention, by setting a first electrode plate 211 so that the projection of the second electrode plate 31 along the first direction X falls on two second electrode plates 31, so that multiple first electrode plates 211 and multiple second electrode plates 31 are staggered in the first direction X, the positions of the acoustic holes 40 can be more aligned with the edge parts of the second electrode plates 31.

[0047] The microphone chip 100 provided by the present invention is provided with a backplate electrode 21 including multiple first electrode plates 211, a diaphragm electrode 30 including multiple second electrode plates 31 and a central column 32, the central column 32 is arranged parallel to the first direction X, multiple first electrode plates 211 are arranged at intervals around the central column 32, and multiple second electrode plates 31 are arranged at intervals around the central column 32 and flexibly connected to the central column 32, so that a capacitor structure is formed between the first electrode plates 211 and the second electrode plates 31, and when the airflow generated by the sound from various directions of the outside world acts on different second electrode plates 31, the second electrode plates 31 and the central column 32 can be twisted. At the same time, since the multiple first electrode plates 211 are conductive and the multiple second electrode plates 31 are conductive at intervals; or, the multiple second electrode plates 31 are conductive and the multiple first electrode plates 211 are conductive at intervals, the twisting of the aforementioned second electrode plates 31 can be converted into a change in capacitance, so that the microphone chip 100 can determine the source direction of the sound by the direction of the change in capacitance, thereby having a sound directional function.

[0048] An embodiment of the present invention also provides a micro-electromechanical microphone 1000, comprising a cover body 200 having a receiving space 1001 and a microphone chip 100 provided in any of the foregoing embodiments of the present invention, the cover body 200 comprising a first connecting hole 201 and a second connecting hole 202, both of which are used to connect the receiving space 1001 with the outside world; the microphone chip 100 is received in the receiving space 1001, and the substrate 10 is connected to the cover body 200 and covers the first connecting hole 201.

[0049] The cover 200 is the outermost structural component of the MEMS microphone 1000 , and its function is to provide support for the internal components of the MEMS microphone 1000 .

[0050] The first communication hole 201 and the second communication hole 202 are both used to connect the receiving space 1001 with the outside, so as to first introduce the airflow generated by the external sound into the receiving space 1001 and then introduce the airflow into the back cavity 101 .

[0051] An embodiment of the present invention further provides a terminal device, comprising the micro-electromechanical microphone 1000 provided by any of the aforementioned embodiments of the present invention.

[0052] The above description is only an embodiment of the present invention. It should be pointed out that those skilled in the art can make improvements without departing from the creative concept of the present invention, but these improvements all fall within the scope of protection of the present invention.

Claims

1. A microphone chip, comprising a substrate, a backplate fixed on the substrate, and a diaphragm electrode disposed opposite to and spaced apart from the backplate in a first direction, wherein a backplate electrode is provided on a side of the backplate facing the diaphragm electrode. The backplane electrode includes a plurality of first electrode plates, the diaphragm electrode includes a plurality of second electrode plates and a central column, the central column is arranged parallel to the first direction, each of the first electrode plates is arranged at intervals around the central column, and each of the second electrode plates is arranged at intervals around the central column and is flexibly connected to the central column; Each of the first electrode plates is conductive, and a plurality of the second electrode plates are conductively spaced apart; alternatively, each of the second electrode plates is conductive, and a plurality of the first electrode plates are conductively spaced apart.

2. The microphone chip according to claim 1, wherein The central column is an insulator and is connected to the backplane.

3. The microphone chip according to claim 1, wherein The central column is a conductor, and the diaphragm electrode further includes a connecting member disposed at an end of the central column away from the backplane, and two ends of the connecting member are respectively connected to the central column and the substrate.

4. The microphone chip according to claim 1, wherein The diaphragm electrode further includes a fixing member disposed at an end of each of the second electrode plates away from the central column, and two ends of the fixing member are respectively connected to the second electrode plate and the substrate.

5. The microphone chip according to claim 4, wherein The fixing member includes a body portion disposed along the direction of surrounding the central column, a first fixing end formed by bending and extending from one end of the body portion toward the central column, and a second fixing end formed by bending and extending from the other end of the body portion away from the central column; The first fixing end is connected to the second electrode plate, and the second fixing end is connected to the substrate.

6. The microphone chip according to claim 1, wherein Along the direction in which the plurality of second electrode plates are arranged at intervals, the distances between the two ends of each of the second electrode plates and the first electrode plate are different.

7. The microphone chip according to claim 1, wherein The projection of one of the first electrode plates along the first direction onto the second electrode plate falls on two of the second electrode plates.

8. The microphone chip according to any one of claims 1 to 7, wherein A plurality of the first electrode plates are connected to the backplane, and the microphone chip further includes a plurality of sound holes penetrating the backplane and each of the first electrode plates along the first direction, and the projection of each of the sound holes along the first direction onto the second electrode plate falls on the second electrode plate.

9. A microelectromechanical microphone, wherein It includes a housing having a receiving space and the microphone chip according to any one of claims 1 to 8, the housing includes a first communication hole and a second communication hole, and both the first communication hole and the second communication hole are used for communicating the receiving space with the outside; The microphone chip is received in the receiving space, and the substrate is connected to the housing and covers the first communication hole.

10. A terminal device, wherein It includes the MEMS microphone according to claim 9.

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