MEMS Microphones

Abstract

The MEMS microphone of the utility model comprises a substrate with a cavity, a back plate arranged above the substrate, a diaphragm arranged between the back plate and the substrate, and a limit structure arranged in the cavity to limit the maximum displacement of the diaphragm away from the back plate, wherein the maximum displacement is not less than the normal working displacement of the diaphragm away from the back plate. The MEMS microphone of the utility model has high reliability.

Description

[Technical field]

[0001] The utility model relates to the field of microphones, in particular to a MEMS microphone. [Background technology]

[0002] A conventional MEMS microphone includes a substrate with a cavity, a back plate disposed above the substrate, and a diaphragm disposed between the back plate and the substrate, wherein the cavity has a shape similar to that of the diaphragm. The diaphragm moves toward or away from the back plate under the action of the impact airflow.

[0003] However, when the impact airflow is large, the diaphragm moves away from the back plate without any obstruction, and the displacement of the diaphragm is large, until it exceeds the limit displacement that the diaphragm material can withstand, causing damage to the diaphragm, resulting in poor reliability of traditional MEMS microphones.

[0004] Therefore, it is necessary to provide a new MEMS microphone to solve the above technical problems. [Contents of the utility model]

[0005] The purpose of the utility model is to overcome the above technical problems and provide a MEMS microphone with improved reliability.

[0006] In order to achieve the above-mentioned object, the utility model provides a MEMS microphone, comprising a substrate having a cavity, a back plate arranged above the substrate, and a diaphragm arranged between the back plate and the substrate, the MEMS microphone also comprising a limiting structure arranged in the cavity to limit the maximum displacement of the diaphragm away from the back plate, the maximum displacement being no less than the normal working displacement of the diaphragm away from the back plate.

[0007] Preferably, the base includes a top wall, a bottom wall opposite to the top wall, and a surrounding wall connecting the top wall and the bottom wall and enclosing the cavity, and the limiting structure includes a single connecting wall connected to the surrounding wall.

[0008] Preferably, the base includes a top wall, a bottom wall opposite to the top wall, and a surrounding wall connecting the top wall and the bottom wall and enclosing the cavity, and the limiting structure includes at least two connecting walls connected to the surrounding wall and cross-arranged.

[0009] Preferably, the at least two connecting walls cross at the same location and form an equal crossing interval.

[0010] Preferably, the base includes a top wall, a bottom wall opposite to the top wall, and a surrounding wall connecting the top wall and the bottom wall and enclosing the cavity, the limiting structure is connected to the surrounding wall, the limiting structure includes a top and a bottom opposite to the top, the top wall is flush with the top, and the bottom wall is flush with the bottom.

[0011] Preferably, the base includes a top wall, a bottom wall opposite to the top wall, and a surrounding wall connecting the top wall and the bottom wall and enclosing the cavity, the limiting structure is connected to the surrounding wall, the limiting structure includes a top and a bottom opposite to the top, the top wall and the top are arranged flush, and the bottom is closer to the diaphragm than the bottom wall.

[0012] Preferably, the base includes a top wall, a bottom wall opposite to the top wall, and a surrounding wall connecting the top wall and the bottom wall and enclosing the cavity, the limiting structure is connected to the surrounding wall, the limiting structure includes a top and a bottom opposite to the top, the bottom wall and the bottom are arranged flush, and the top wall is closer to the diaphragm than the top.

[0013] Preferably, the base includes a top wall, a bottom wall opposite to the top wall, and a surrounding wall connecting the top wall and the bottom wall and enclosing the cavity, the limiting structure is connected to the surrounding wall, the limiting structure includes a top and a bottom opposite to the top, the top wall is closer to the diaphragm relative to the top, and the bottom is closer to the diaphragm relative to the bottom wall.

[0014] Preferably, the base and the limiting structure are integrally formed.

[0015] In the MEMS microphone of the utility model, a limiting structure for limiting the maximum displacement of the diaphragm away from the back plate is provided in the cavity of the base, so that the displacement of the diaphragm away from the back plate will not exceed the limit displacement that the diaphragm material can withstand, thereby avoiding damage to the diaphragm caused by the displacement of the diaphragm away from the back plate exceeding the limit displacement that the diaphragm material can withstand, and improving the reliability of the MEMS microphone. In addition, the maximum displacement of the diaphragm away from the back plate limited by the limiting structure is not less than the normal working displacement of the diaphragm away from the back plate, so that the setting of the limiting structure will not affect the normal working of the MEMS microphone.

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 use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in the field of the present invention, other drawings can be obtained based on these drawings without creative work, among which:

[0017] Figure 1 It is a schematic cross-sectional structural diagram of a first MEMS microphone of the utility model;

[0018] Figure 2It is a cross-sectional structural schematic diagram of a combination of a substrate and a limiting structure of a first MEMS microphone of the utility model;

[0019] Figure 3 This is a schematic diagram of the combined structure of the substrate and the limiting structure of the first MEMS microphone of the utility model;

[0020] Figure 4 It is a schematic diagram of the combined structure of the substrate and the limiting structure of the second MEMS microphone of the utility model;

[0021] Figure 5 This is a schematic diagram of the combined structure of the substrate and the limiting structure of the third MEMS microphone of the present invention;

[0022] Figure 6 It is a cross-sectional structural schematic diagram of a combination of a substrate and a limiting structure of a fourth MEMS microphone of the present invention;

[0023] Figure 7 It is a cross-sectional structural schematic diagram of a combination of a substrate and a limiting structure of a fifth MEMS microphone of the present utility model;

[0024] Figure 8 It is a schematic cross-sectional structural diagram of a combination of a substrate and a limiting structure of a sixth MEMS microphone of the present invention. [Specific implementation method]

[0025] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in the field of the utility model without creative work are within the scope of protection of the utility model.

[0026] See also Figures 1 to 3 As shown, the utility model provides a MEMS microphone 100 , which includes a substrate 1 having a cavity 10 , a back plate 2 disposed above the substrate 1 , and a diaphragm 3 disposed between the back plate 2 and the substrate 1 .

[0027] The base 1 includes a top wall 11 , a bottom wall 12 opposite to the top wall 11 , and a surrounding wall 13 connecting the top wall 11 and the bottom wall 12 and surrounding the cavity 10 .

[0028] The MEMS microphone 100 further includes a limiting structure 4 disposed in the cavity 10 for limiting a maximum displacement of the diaphragm 3 away from the back plate 2 , wherein the maximum displacement is not less than a normal working displacement of the diaphragm 3 away from the back plate 2 .

[0029] In this embodiment, the limiting structure 4 is connected to the surrounding wall 13. Of course, in other embodiments, the limiting structure 4 is not limited to being connected to the surrounding wall 13. Any form of the limiting structure 4 that can be formed in the cavity 10 is feasible.

[0030] In this embodiment, the limiting structure 4 is two connecting walls 40 connected to the surrounding wall 13 and arranged crosswise. Preferably, the two connecting walls 40 cross to form four 90-degree cross intervals S1.

[0031] In this embodiment, the limiting structure 4 includes a top 41 and a bottom 42 opposite to the top 41 , the top wall 11 and the top 41 are flush with each other, and the bottom wall 12 and the bottom 42 are flush with each other.

[0032] In other embodiments, for example, Figure 4 As shown, the limiting structure 4 can also be a single connecting wall 40 connected to the surrounding wall 13; for example, Figure 5 As shown, the limiting structure 4 may also be three connecting walls 40 connected to the surrounding wall 13 and arranged crosswise, preferably, the three connecting walls 40 cross at the same place and form six 60-degree crossing intervals S2. In other embodiments, the limiting structure 4 may further be more than three connecting walls 40 connected to the surrounding wall 13 and arranged crosswise, preferably, more than three connecting walls 40 cross at the same place and form equal crossing intervals.

[0033] In other embodiments, for example, Figure 6 As shown, the limiting structure 4 can also be connected to the surrounding wall 13 , the top wall 11 and the top 41 are arranged flush, and the bottom 42 is closer to the diaphragm 3 than the bottom wall 12 .

[0034] In other embodiments, for example, Figure 7 As shown, the limiting structure 4 can also be connected to the surrounding wall 13, the bottom wall 12 and the bottom 42 are arranged flush, and the top wall 11 is closer to the diaphragm 3 than the top 41. The distance between the diaphragm 3 and the limiting structure 4 is appropriately increased, which can reduce the compression film damping formed by the limiting structure 4 on the diaphragm 3.

[0035] In other embodiments, for example, Figure 8As shown, the limiting structure 4 can also be connected to the surrounding wall 13, the top wall 11 is closer to the diaphragm 3 than the top 41, and the bottom 42 is closer to the diaphragm 3 than the bottom wall 12. By appropriately increasing the distance between the diaphragm 3 and the limiting structure 4, the compression film damping formed by the limiting structure 4 on the diaphragm 3 can be reduced.

[0036] As an optional manner, the base 1 and the limiting structure 4 are integrally formed, and the limiting structure 4 is formed together when the cavity 10 is formed, that is, the limiting structure 4 can be formed by a part of the base material forming the base 1.

[0037] In the MEMS microphone of the utility model, a limiting structure for limiting the maximum displacement of the diaphragm away from the back plate is provided in the cavity of the base, so that the displacement of the diaphragm away from the back plate will not exceed the limit displacement that the diaphragm material can withstand, thereby avoiding damage to the diaphragm caused by the displacement of the diaphragm away from the back plate exceeding the limit displacement that the diaphragm material can withstand, and improving the reliability of the MEMS microphone. In addition, the maximum displacement of the diaphragm away from the back plate limited by the limiting structure is not less than the normal working displacement of the diaphragm away from the back plate, so that the setting of the limiting structure will not affect the normal working of the MEMS microphone.

[0038] The above is only an implementation method of the present invention. It should be pointed out that ordinary technicians in the field of the present invention can make improvements without departing from the creative concept of the present invention, but these all fall within the scope of protection of the present invention.

Claims

1. A MEMS microphone, comprising a substrate having a cavity, a back plate disposed above the substrate, and a diaphragm disposed between the back plate and the substrate, characterized in that: The MEMS microphone further includes a limiting structure disposed in the cavity for limiting a maximum displacement of the diaphragm away from the back plate, wherein the maximum displacement is not less than a normal working displacement of the diaphragm away from the back plate.

2. The MEMS microphone according to claim 1, characterized in that: The base includes a top wall, a bottom wall opposite to the top wall, and a surrounding wall connecting the top wall and the bottom wall and surrounding the cavity, and the limiting structure includes a single connecting wall connected to the surrounding wall.

3. The MEMS microphone according to claim 1, characterized in that: The base includes a top wall, a bottom wall opposite to the top wall, and a surrounding wall connecting the top wall and the bottom wall and surrounding the cavity, and the limiting structure includes at least two connecting walls connected to the surrounding wall and arranged crosswise.

4. The MEMS microphone according to claim 3, characterized in that: The at least two connecting walls cross at the same position and form an equal crossing interval.

5. The MEMS microphone according to claim 1, characterized in that: The base includes a top wall, a bottom wall opposite to the top wall, and a surrounding wall connecting the top wall and the bottom wall and enclosing the cavity, the limiting structure is connected to the surrounding wall, the limiting structure includes a top and a bottom opposite to the top, the top wall is flush with the top, and the bottom wall is flush with the bottom.

6. The MEMS microphone according to claim 1, characterized in that: The base includes a top wall, a bottom wall opposite to the top wall, and a surrounding wall connecting the top wall and the bottom wall and enclosing the cavity, the limiting structure is connected to the surrounding wall, the limiting structure includes a top and a bottom opposite to the top, the top wall and the top are arranged flush, and the bottom is closer to the diaphragm than the bottom wall.

7. The MEMS microphone according to claim 1, characterized in that: The base includes a top wall, a bottom wall opposite to the top wall, and a surrounding wall connecting the top wall and the bottom wall and enclosing the cavity, the limiting structure is connected to the surrounding wall, the limiting structure includes a top and a bottom opposite to the top, the bottom wall and the bottom are arranged flush, and the top wall is closer to the diaphragm than the top.

8. The MEMS microphone according to claim 1, characterized in that: The base includes a top wall, a bottom wall opposite to the top wall, and a surrounding wall connecting the top wall and the bottom wall and enclosing the cavity, the limiting structure is connected to the surrounding wall, the limiting structure includes a top and a bottom opposite to the top, the top wall is closer to the diaphragm relative to the top, and the bottom is closer to the diaphragm relative to the bottom wall.

9. The MEMS microphone according to claim 1, characterized in that: The base and the limiting structure are integrally formed.

Images