CN116801146A

CN116801146A - Microelectromechanical device

Info

Publication number: CN116801146A
Application number: CN202210264001.1A
Authority: CN
Inventors: 陈振颐; 李岳刚; 张朝森
Original assignee: Merry Electronics Shenzhen Co ltd
Current assignee: Merry Electronics Shenzhen Co ltd
Priority date: 2022-03-17
Filing date: 2022-03-17
Publication date: 2023-09-22

Abstract

The invention relates to a micro-electromechanical device, which comprises a shell, a vibration sensor, a vibrating diaphragm assembly and a micro-electromechanical microphone. The shell comprises a sound receiving hole, and the vibration sensor is arranged in the shell. The vibrating diaphragm assembly is arranged in the shell and corresponds to the vibration sensor. The micro-electromechanical microphone is arranged in the shell and corresponds to the sound receiving hole, a back cavity of the micro-electromechanical microphone is formed in the shell, and a projection part of the range covered by the back cavity to the plane of the vibrating diaphragm assembly is overlapped on the vibrating diaphragm assembly.

Description

Microelectromechanical device

Technical Field

The present invention relates to an electronic device, and more particularly, to a microelectromechanical device.

Background

Microelectromechanical microphones and vibration sensors are already hard devices of fairly sophisticated technology on the market today. The microelectromechanical microphone is adapted to receive acoustic signals from the air, and the vibration sensor is adapted to receive vibration signals from the solid. However, there is no related art integrating a mems microphone and a vibration sensor in the market. Therefore, how to integrate the mems microphone and the vibration sensor into a single body and effectively improve the sensing effect of the mems microphone and the vibration sensor is a research direction in the art.

Disclosure of Invention

Based on the above, the invention provides a micro-electromechanical device with good sound sensing and vibration sensing effects.

The micro-electromechanical device comprises a shell, a vibration sensor, a vibrating diaphragm assembly and a micro-electromechanical microphone. The shell comprises a sound receiving hole, and the vibration sensor is arranged in the shell. The vibrating diaphragm assembly is arranged in the shell and corresponds to the vibration sensor. The micro-electromechanical microphone is arranged in the shell and corresponds to the sound receiving hole, wherein a back cavity of the micro-electromechanical microphone is formed in the shell, and a projection part of the range covered by the back cavity to the plane of the vibrating diaphragm assembly is overlapped with the vibrating diaphragm assembly.

In an embodiment of the invention, the housing includes a base, the base includes a first base plate, a second base plate located above the first base plate and spaced apart from the first base plate, and the vibration sensor and the mems microphone are disposed on the second base plate.

In an embodiment of the invention, the first bottom plate includes a first receiving hole, the second bottom plate includes a second receiving hole corresponding to the first receiving hole, and the first receiving hole and the second receiving hole form a receiving hole together.

In an embodiment of the invention, the housing includes a side housing, the side housing is disposed on the second bottom plate, the side housing includes a side wall, a first inner partition and a second inner partition disposed in the side wall, the vibration sensor is disposed between the first inner partition and the second inner partition, and the mems microphone is separated from the vibration sensor by the second inner partition.

In an embodiment of the invention, the second bottom plate includes at least one first through hole, a second through hole and at least one third through hole, the first inner partition plate and a portion of the side wall form an air flow channel, the at least one first through hole is opposite to the air flow channel, the vibration sensor covers the second through hole of the second bottom plate, and the at least one third through hole is a portion of the back cavity.

In an embodiment of the invention, the second bottom plate includes a long side and a short side, and the first through hole is near the short side and extends along the direction of the short side.

In an embodiment of the invention, the second bottom plate includes a long side and a short side, and the first through hole is near the long side and extends along the long side.

In an embodiment of the invention, the second bottom plate includes a long side and a short side, and the at least one first through hole includes a plurality of first through holes, and the first through holes are close to the long side and are arranged along the direction of the long side.

In an embodiment of the invention, a diameter of the first through hole is greater than 100 μm, and a number of the first through holes is greater than or equal to three.

In an embodiment of the invention, in the microelectromechanical device, a first cavity is formed between the first bottom plate and the second bottom plate, the airflow channel is communicated with the first cavity through the first through hole, and the back cavity is separated from the first cavity.

In an embodiment of the invention, the microelectromechanical device further includes an upper cover, wherein the side case is located between the base and the upper cover, and the back cavity is formed between the second inner partition, a portion of the side wall, the first bottom plate, the second bottom plate, and the upper cover.

In an embodiment of the invention, a projection portion of a portion of the back cavity between the first bottom plate and the second bottom plate on a plane of the diaphragm assembly overlaps the diaphragm assembly.

In an embodiment of the invention, the microelectromechanical device further includes an upper cover, wherein the side shell is located between the base and the upper cover, the diaphragm assembly is disposed between the side shell and the upper cover, a first cavity is formed between the first bottom plate and the second bottom plate, a projection area of the first cavity to the first bottom plate is smaller than a projection area of the back cavity to the first bottom plate, a second cavity is located between the first inner partition and the second inner partition, a third cavity is formed between the diaphragm assembly and the upper cover, and the third cavity is in air communication with the first cavity through the air flow channel.

Based on the above, in the microelectromechanical device of the present invention, the vibration sensor and the microelectromechanical microphone are both located in the housing, and the projection of the area covered by the back cavity where the microelectromechanical microphone is located on the plane where the diaphragm assembly is located is overlapped on the diaphragm assembly, so as to increase the back cavity of the microelectromechanical microphone, and facilitate the sound wave to more easily push the thin film structure of the microelectromechanical microphone to vibrate, thereby improving the sensitivity of the microelectromechanical microphone. In addition, the micro-electromechanical device integrates the vibration sensor and the micro-electromechanical microphone, so that the micro-electromechanical device can simultaneously sense bone conduction vibration of a user and acoustic signals in the air, and therefore, the micro-electromechanical device can have better sensing capability.

Drawings

FIG. 1 is a schematic cross-sectional view of a microelectromechanical device according to an embodiment of the invention.

Fig. 2 is a schematic top view of a second base plate of the microelectromechanical device of fig. 1.

Fig. 3 is a schematic cross-sectional view of the microelectromechanical device of fig. 1 in another position.

Fig. 4 is a schematic top view of a second substrate of a microelectromechanical device according to another embodiment of the invention.

Fig. 5 is a schematic top view of a second substrate of a microelectromechanical device according to another embodiment of the invention.

Reference numerals:

100. 100A, 100B microelectromechanical devices

110 casing body

111 radio hole

112 base

113 first bottom plate

1131 first sub-radio hole

114. 114A, 114B second bottom plate

1141 second sub-radio hole

1142. 1142A, 1142B first perforation

1143. 1143A, 1143B second perforations

1144 third perforation

1145 Long side

1146 short side

115 side shell

1151 side wall

1152 first inner separator

1153 second inner separator

120 vibration sensor

130 vibrating diaphragm assembly

140 micro-electromechanical microphone

141 film structure

142. 142A, 142B back cavity

150 upper cover

AA. BB section line

C1, C1A, C B first Cavity

C2 second chamber

C3 third chamber

H1, H2, H3, H4 spacer

P: airflow passage

S: acoustic wave

Detailed Description

Fig. 1 is a schematic cross-sectional view of a microelectromechanical device according to an embodiment of the invention, fig. 2 is a schematic top view of a second substrate of the microelectromechanical device of fig. 1, and fig. 3 is a schematic cross-sectional view of the microelectromechanical device of fig. 1 in another position.

It should be noted that, fig. 2 includes a section line AA and a section line BB. Fig. 1 and 3 are schematic cross-sectional views of a microelectromechanical device along section lines AA and BB according to an embodiment of the invention.

Referring to fig. 1 to 3, the microelectromechanical device 100 of the present embodiment includes a housing 110, a vibration sensor 120, a diaphragm assembly 130, and a microelectromechanical microphone 140. The housing 110 includes a sound receiving hole 111, and the vibration sensor 120 is disposed in the housing 110. The diaphragm assembly 130 is disposed in the housing 110 and corresponds to the vibration sensor 120. The mems microphone 140 has a membrane structure 141 and the mems microphone 140 is disposed within the housing 110. In addition, the micro-electromechanical microphone 140 corresponds to the sound receiving hole 111.

In this embodiment, the microelectromechanical device 100 incorporates a vibration sensor 120 and a microelectromechanical microphone 140. Thus, when the mems device 100 is used as a headset (not shown), such as an element of an earphone, it can sense bone conduction vibration of a user and acoustic signals in air at the same time, and thus the mems device 100 can have better sensing capability.

Further, the housing 110 of the present embodiment includes a side case 115. The side housing 115 includes a side wall 1151 and a first inner partition 1152 and a second inner partition 1153 within the side wall 1151. The vibration sensor 120 is located between the first and second inner separators 1152 and 1153, and the microelectromechanical microphone 140 is separated from the vibration sensor 120 by the second inner separator 1153. Further, the mems microphone 140 and the vibration sensor 120 share the second inner separator 1153, and the mems microphone 140 and the vibration sensor 120 may not need to have respective inner separators, which helps to reduce the overall volume of the mems device 100.

Furthermore, the housing 110 of the present embodiment includes a base 112, and the base 112 includes a first bottom plate 113 and a second bottom plate 114. The second bottom plate 114 is located above the first bottom plate 113 and is separated from the first bottom plate 113 by a spacer H1. The side case 115 is disposed on the second base plate 114 through a spacer H2, and the vibration sensor 120 and the mems microphone 140 are also disposed on the second base plate 114. Further, the vibration sensor 120 and the microelectromechanical microphone 140 share the second base 114. The spacers H1 and H2 in the present embodiment are tin, but the present invention is not limited thereto.

In addition, a back cavity 142 of the mems microphone 140 is formed in the housing 110 of the present embodiment, and the range of the back cavity 142 covers the cavity where the mems microphone 140 is located as shown by the dashed lines in fig. 1 and 3, and extends to the space between the first substrate 113 and the second substrate 114. The space of the back cavity 142 between the first bottom plate 113 and the second bottom plate 114 corresponds to the extent on the first bottom plate 113 as shown in fig. 2. The projection of the area of the back cavity 142 between the first bottom plate 113 and the second bottom plate 114 onto the plane of the diaphragm assembly 130 overlaps the diaphragm assembly 130. In other words, the back cavity 142 covers a portion of the vibration sensor 120 corresponding to the space within the first and second bottom plates 113 and 114 to increase the size of the back cavity 142.

The back cavity space of the mems microphone of the prior art is difficult to be effectively increased without changing the volume of the mems microphone itself due to the design of the mems microphone as a separate element. In the above configuration of the mems device 100 of the present embodiment, the mems microphone 140 is further beneficial to the sound wave S to more easily push the thin film structure 141 of the mems microphone 140 to vibrate due to the increase of the back cavity 141, so as to improve the sensitivity of the mems microphone 140 to the sound wave S.

In the present embodiment, the first bottom plate 113 of the base 112 includes a first sub-receiving hole 1131, and the second bottom plate 114 includes a second sub-receiving hole 1141 corresponding to the first sub-receiving hole 1131. The first sub-sound-receiving hole 1131 and the second sub-sound-receiving hole 1141 together form the sound-receiving hole 111. After the sound wave S sequentially passes through the first sub-sound receiving hole 1131 and the second sub-sound receiving hole 1141, the thin film structure 141 of the mems microphone 140 is pushed to vibrate and is read by the mems microphone 140 in a voltage signal manner.

In the present embodiment, the second bottom plate 114 of the base 112 includes at least one first through hole 1142, a second through hole 1143, and at least one third through hole 1144. The first inner partition 1152 and a portion of the side wall 1151 form an airflow channel P, and the first through hole 1142 covers the second through hole 1143 of the second base plate 114 with respect to the airflow channel P. In addition, a first cavity C1 of the microelectromechanical device 100 is formed between the first substrate 113 and the second substrate 114. The air flow channel P is connected to the first cavity C1 through the first through hole 1142, and the vibration sensor 120 covering the second through hole 1143 is also connected to the first cavity C1 through the second through hole 1143, in other words, the vibration sensor 120 and the air flow channel P are mutually connected through the first cavity C1.

In addition, the third through hole 1144 of the present embodiment is a part of the back cavity 142, and the back cavity 142 is separated from the first cavity C1 by the spacer H1. The projection area of the first cavity C1 on the first bottom plate 113 is smaller than the projection area of the back cavity 142 on the first bottom plate 113, i.e. the range of the first cavity C1 on the first bottom plate 113 is smaller than the range of the back cavity 142 on the first bottom plate 113 as shown in fig. 2. In other embodiments of the present invention, the extent of the first cavity C1 on the first bottom plate 113 may be equal to the extent of the back cavity 142 on the first bottom plate 113, which is not limited by the present invention.

In this embodiment, the microelectromechanical device 100 further includes a top cover 150, wherein the side case 115 is located between the base 112 and the top cover 150. The back chamber 142 is formed between the second inner partition 1153, a portion of the side wall 1151, the first bottom plate 113, the second bottom plate 114, and the upper cover 150 as shown in fig. 1 and 3.

In the present embodiment, a spacer H3 is disposed between the diaphragm assembly 130 and the side case 115, and a spacer H4 is disposed between the diaphragm assembly 130 and the upper cover 150. The spacers H3 and H4 in this embodiment are respectively made of tin and silica gel, but the invention is not limited thereto.

In this embodiment, a second chamber C2 of the microelectromechanical device 100 is located between the first inner separator 1152 and the second inner separator 1153. A third chamber C3 is formed between the diaphragm assembly 130 and the upper cover 150, and the third chamber C3 is in air communication with the first chamber C1 through the air flow channel P. In this way, a portion of the air pressure in the first chamber C1 can flow to the third chamber C3 through the air flow channel P, so that the air can flow back to the upper portion of the diaphragm assembly 130, and a greater pressure can be provided to enhance the sensitivity of the vibration sensor 120. The vibration sensor 120 thus has better performance, high sensitivity, and better low frequency profile performance.

Referring to fig. 1 and 2, the second bottom plate 114 of the present embodiment includes a long side 1145 (fig. 2) and a short side 1146 (fig. 2), and the dimensions of the second bottom plate 114 correspond to those of the first bottom plate 113 as shown in fig. 1. The first bottom plate 113 also includes a long side and a short side. The first through hole 1142 is rectangular in shape and is adjacent to the short side 1146, and the first through hole 1142 extends along the direction of the short side 1146. Accordingly, the first bottom plate 113 has a long and narrow shape due to the shape and the position of the first through hole 1142, so that the overall size of the mems device 100 can be adjusted according to the user's requirement, so as to ensure that the mems device 100 can be applied to devices with different sizes.

Fig. 4 is a schematic top view of a second substrate of a microelectromechanical device according to another embodiment of the invention. Referring to fig. 2 and 4, the difference between the microelectromechanical device 100A (not labeled) of the present embodiment and the microelectromechanical device 100 of the previous embodiment is that the first through hole 1142A (fig. 4) of the microelectromechanical device 100A is located near the long side 1145, and the first through hole 1142A extends along the direction of the long side 1145. The position of the second through hole 1143A is adjusted toward the short side 1146. In this way, the range of the back cavity 142A (fig. 4) is larger than that of the back cavity 142 shown in fig. 2, and the ranges of the back cavity 142A and the first cavity C1A (fig. 4) can be adjusted according to the user's needs, so as to achieve the customization effect.

Fig. 5 is a schematic top view of a second substrate of a microelectromechanical device according to another embodiment of the invention. Referring to fig. 4 and 5, the difference between the microelectromechanical device 100B (not shown) of the present embodiment and the microelectromechanical device 100A (not shown) of the previous embodiment is that the shape of the first through hole 1142B (fig. 5) of the microelectromechanical device 100B is circular, and the first through hole 1142B includes a plurality of first through holes 1142B. The first through holes 1142B are located near the long side 1145 and are aligned along the direction of the long side 1145. It is noted that the diameter of each first through hole 1142B may be greater than 100 micrometers (μm), and the number of the first through holes 1142B may be greater than or equal to three. In this way, the air flow passage (not shown) located in the first through hole 1142B has sufficient air flow to balance the pressure in the first chamber C1B (fig. 5) and the third chamber (not shown), so that the air can flow back over the diaphragm assembly 130, and a larger pressure can be provided to enhance the sensitivity of the vibration sensor 120. The vibration sensor 120 thus has better performance, high sensitivity, and better low frequency profile performance. In other embodiments of the present invention, the shape of the first through hole 1142B may be diamond or triangle, which is not limited by the present invention.

In summary, in the microelectromechanical device of the present invention, the projection portion of the area covered by the back cavity on the plane of the diaphragm assembly overlaps the diaphragm assembly, so as to increase the space of the back cavity, facilitate the sound wave to more easily push the thin film structure of the microelectromechanical microphone to vibrate, and improve the sensitivity of the microelectromechanical microphone to the sound wave. In addition, the micro-electromechanical device integrates the vibration sensor and the micro-electromechanical microphone, and can simultaneously sense bone conduction vibration of a user and acoustic signals in air when being worn as a component of the head-mounted device, so that the micro-electromechanical device has better sensing capability. Furthermore, part of the air pressure in the first chamber of an embodiment can flow to the third chamber via the air flow channel to effectively perform pressure balancing. The vibrating diaphragm assembly can move more smoothly due to pressure balance, and has better efficiency, high sensitivity and better low-frequency curve performance. The range of the back cavity and the first cavity in one embodiment can also be adjusted according to the requirements of the user, so as to achieve the effect of customization.

Claims

1. A microelectromechanical device, comprising:

a shell comprising a sound receiving hole;

a vibration sensor arranged in the shell;

the vibrating diaphragm assembly is arranged in the shell and corresponds to the vibration sensor; and

the micro-electromechanical microphone is arranged in the shell and corresponds to the sound receiving hole, a back cavity of the micro-electromechanical microphone is formed in the shell, and a projection part of the coverage range of the back cavity to the plane of the vibrating diaphragm assembly is overlapped with the vibrating diaphragm assembly.

2. The microelectromechanical device of claim 1, wherein the housing comprises a base including a first base plate, a second base plate spaced above the first base plate, the vibration sensor and the microelectromechanical microphone being disposed on the second base plate.

3. The microelectromechanical device of claim 2, wherein the first base plate includes a first sub-sound receiving aperture, the second base plate includes a second sub-sound receiving aperture corresponding to the first sub-sound receiving aperture, and the first sub-sound receiving aperture and the second sub-sound receiving aperture together comprise the sound receiving aperture.

4. The microelectromechanical device of claim 2, wherein the housing comprises a side shell disposed on the second base plate, the side shell comprising a sidewall and a first and a second inner diaphragm disposed within the sidewall, the vibration sensor being disposed between the first and second inner diaphragms, the microelectromechanical microphone being spaced from the vibration sensor by the second inner diaphragm.

5. The microelectromechanical device of claim 4, wherein the second base plate includes at least a first aperture, a second aperture, and at least a third aperture, the first inner partition and a portion of the sidewall form an airflow channel, the at least a first aperture is located in the airflow channel, the vibration sensor covers the second aperture of the second base plate, and the at least a third aperture is a portion of the back cavity.

6. The microelectromechanical device of claim 5, wherein the second base plate includes a long side and a short side, and the first aperture is adjacent to the short side and extends along the direction of the short side.

7. The microelectromechanical device of claim 5, wherein the second base plate includes a long side and a short side, and the first aperture is adjacent to and extends along the long side.

8. The microelectromechanical device of claim 5, wherein the second base plate comprises a long side and a short side, and the at least one first perforation comprises a plurality of first perforations, the first perforations being adjacent to the long side and aligned along the long side.

9. The microelectromechanical device of claim 8, wherein each of the first perforations has a diameter greater than 100 microns and the number of first perforations is greater than or equal to three.

10. The microelectromechanical device of claim 5, wherein a first cavity is formed between the first base plate and the second base plate, the airflow channel is in communication with the first cavity through the first aperture, and the back cavity is spaced apart from the first cavity.

11. The microelectromechanical device of claim 4, further comprising an upper cover, wherein the side housing is positioned between the base and the upper cover, and the back cavity is formed between the second inner spacer, a portion of the sidewall, the first bottom plate, the second bottom plate, and the upper cover.

12. The microelectromechanical device of claim 11, wherein a projection of a portion of the back cavity between the first base plate and the second base plate onto a plane of the diaphragm assembly overlaps the diaphragm assembly.

13. The microelectromechanical device of claim 5, further comprising an upper cover, wherein the side housing is positioned between the base and the upper cover, the diaphragm assembly is positioned between the side housing and the upper cover, a first cavity is formed between the first base plate and the second base plate, a projected area of the first cavity to the first base plate is smaller than a projected area of the back cavity to the first base plate, a second cavity is positioned between the first inner partition and the second inner partition, a third cavity is formed between the diaphragm assembly and the upper cover, and the third cavity is in air communication with the first cavity via the air flow channel.