MEMS microphone

Abstract

The present utility model provides a MEMS microphone, comprising a substrate having a cavity, a backplate disposed above the substrate, a diaphragm disposed between the backplate and the substrate, and a limiting structure disposed in the cavity for limiting a maximum displacement of the diaphragm away from the backplate, wherein the maximum displacement is not less than a normal operating displacement of the diaphragm away from the backplate. The MEMS microphone of the present utility model has high reliability.

Description

MEMS microphone TECHNICAL FIELD

[0001] The utility model relates to the field of microphone, especially a MEMS microphone. BACKGROUND

[0002] The traditional MEMS microphone includes a substrate with a cavity, a back plate arranged above the substrate, and a diaphragm arranged between the back plate and the substrate, and the cavity has a similar shape to the diaphragm. The diaphragm moves towards the back plate or away from the back plate under the action of the impact airflow. TECHNICAL PROBLEM

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

[0004] Therefore, it is necessary to provide a new MEMS microphone to solve the above technical problems. TECHNICAL SOLUTION

[0005] The utility model aims at overcoming the above technical problems, and provides a MEMS microphone which can improve the reliability.

[0006] In order to achieve the above purpose, the utility model provides a MEMS microphone, which includes a substrate with a cavity, a back plate arranged above the substrate, and a diaphragm arranged between the back plate and the substrate, and the MEMS microphone further includes a limiting structure arranged in the cavity to limit the maximum displacement of the diaphragm away from the back plate, and the maximum displacement is not less than the normal working displacement of the diaphragm away from the back plate.

[0007] Preferably, the substrate 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.

[0008] Preferably, the substrate 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 in cross.

[0009] Preferably, the at least two connecting walls cross at the same place and form equal cross intervals.

[0010] Preferably, the base comprises 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, the limiting structure is connected to the surrounding wall, the limiting structure comprises a top portion and a bottom portion opposite to the top portion, the top wall is flush with the top portion, and the bottom wall is flush with the bottom portion.

[0011] Preferably, the base comprises 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, the limiting structure is connected to the surrounding wall, the limiting structure comprises a top portion and a bottom portion opposite to the top portion, the top wall is flush with the top portion, and the bottom portion is closer to the diaphragm than the bottom wall.

[0012] Preferably, the base comprises 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, the limiting structure is connected to the surrounding wall, the limiting structure comprises a top portion and a bottom portion opposite to the top portion, the bottom wall is flush with the bottom portion, and the top wall is closer to the diaphragm than the top portion.

[0013] Preferably, the base comprises 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, the limiting structure is connected to the surrounding wall, the limiting structure comprises a top portion and a bottom portion opposite to the top portion, the top wall is closer to the diaphragm than the top portion, and the bottom portion is closer to the diaphragm than the bottom wall.

[0014] Preferably, the base is integrally formed with the limiting structure. Advantageous effects

[0015] In the MEMS microphone, the limiting structure is arranged in the cavity of the base to limit the maximum displacement of the diaphragm away from the back plate, so that the displacement of the diaphragm away from the back plate does not exceed the limit displacement that can be borne by the diaphragm material, thereby avoiding damage to the diaphragm caused by the displacement of the diaphragm away from the back plate exceeding the limit displacement that can be borne by the diaphragm material, 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 limiting structure does not affect the normal working of the MEMS microphone. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the technical scheme in the embodiments of the present application, the drawings needed to be used in the following embodiment description will be briefly introduced, obviously, the drawings in the following description are only some embodiments of the present application, and for the ordinary skilled in the present application, other drawings can be obtained without creative labor on the premise of the drawings.

[0017] Fig. 1 is a sectional structure schematic diagram of the first MEMS microphone of the present application;

[0018] Fig. 2 is a sectional structure schematic diagram of the combination of the base and the limiting structure of the first MEMS microphone of the present application;

[0019] Fig. 3 is a combination structure schematic diagram of the base and the limiting structure of the first MEMS microphone of the present application;

[0020] Fig. 4 is a combination structure schematic diagram of the base and the limiting structure of the second MEMS microphone of the present application;

[0021] Fig. 5 is a combination structure schematic diagram of the base and the limiting structure of the third MEMS microphone of the present application;

[0022] Fig. 6 is a sectional structure schematic diagram of the combination of the base and the limiting structure of the fourth MEMS microphone of the present application;

[0023] Fig. 7 is a sectional structure schematic diagram of the combination of the base and the limiting structure of the fifth MEMS microphone of the present application;

[0024] Fig. 8 is a sectional structure schematic diagram of the combination of the base and the limiting structure of the sixth MEMS microphone of the present application. Best mode of the present application

[0025] The technical scheme in the embodiments of the present application will be described clearly and completely below in combination with the drawings in the embodiments of the present application, obviously, the described embodiments are only some embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by the ordinary skilled in the present application without creative labor are within the protection scope of the present application.

[0026] Please refer to Figs. 1 to 3, the present application provides a MEMS microphone 100, the MEMS microphone 100 includes a base 1 with a cavity 10, a back plate 2 arranged above the base 1, and a diaphragm 3 arranged between the back plate 2 and the base 1.

[0027] The base 1 comprises 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 enclosing the cavity 10.

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

[0029] In the 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 be connected to the surrounding wall 13, as long as the limiting structure 4 can be formed in any form in the cavity 10.

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

[0031] In the embodiment, the limiting structure 4 comprises a top part 41 and a bottom part 42 opposite to the top part 41, the top wall 11 and the top part 41 are flushly disposed, and the bottom wall 12 and the bottom part 42 are flushly disposed.

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

[0033] In other embodiments, for example, as shown in FIG. 6, the limiting structure 4 can also be connected to the surrounding wall 13, the top wall 11 and the top part 41 are flushly disposed, and the bottom part 42 is closer to the diaphragm 3 relative to the bottom wall 12.

[0034] In other embodiments, for example, as shown in FIG. 7, the limiting structure 4 can also be connected to the surrounding wall 13, the bottom wall 12 and the bottom part 42 are flushly disposed, and the top wall 11 is closer to the diaphragm 3 relative to the top part 41, appropriately increasing the distance between the diaphragm 3 and the limiting structure 4 can reduce the membrane damping formed by the limiting structure 4 on the diaphragm 3.

[0035] In other embodiments, for example as shown in Figure 8, the limiting structure 4 can also be connected to the surrounding wall 13, the top wall 11 is closer to the diaphragm 3 relative to the top portion 41, the bottom portion 42 is closer to the diaphragm 3 relative to the bottom wall 12, and the distance between the diaphragm 3 and the limiting structure 4 is appropriately increased, which can reduce the film damping formed by the limiting structure 4 on the diaphragm 3.

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

[0037] In the MEMS microphone, the limiting structure is arranged in the cavity of the substrate to limit the maximum displacement of the diaphragm away from the back plate, so that the displacement of the diaphragm away from the back plate does not exceed the limit displacement that the diaphragm material can withstand, thereby avoiding the damage of 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 limiting structure does not affect the normal working of the MEMS microphone.

[0038] The above is only the embodiment of the utility model, and it should be pointed out that for ordinary skilled person in the art of the utility model, improvements can be made without departing from the creative concept of the utility model, but these all belong to the protection scope of the utility model.

Claims

1. A MEMS microphone comprising a substrate having a cavity, a backplate disposed above the substrate, and a diaphragm disposed between the backplate and the substrate, characterized by, The MEMS microphone further comprises a limiting structure arranged in the cavity for limiting a maximum displacement of the diaphragm away from the back plate, the maximum displacement being not less than a normal working displacement of the diaphragm away from the back plate.

2. The MEMS microphone according to claim 1, wherein, The base comprises 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 comprises a single connecting wall connected to the surrounding wall.

3. The MEMS microphone of claim 1, wherein, The base comprises 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 comprises at least two connecting walls connected to the surrounding wall and arranged in cross.

4. The MEMS microphone of claim 3, wherein, The at least two connecting walls cross at the same position and form equal cross intervals.

5. The MEMS microphone of claim 1, wherein, The base comprises 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 is connected to the surrounding wall, the limiting structure comprises a top portion and a bottom portion opposite to the top portion, the top wall and the top portion are arranged in flush, and the bottom wall and the bottom portion are arranged in flush.

6. The MEMS microphone of claim 1, wherein, The base comprises 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 is connected to the surrounding wall, the limiting structure comprises a top portion and a bottom portion opposite to the top portion, the top wall and the top portion are arranged in flush, and the bottom portion is closer to the diaphragm relative to the bottom wall.

7. The MEMS microphone of claim 1, wherein, The base comprises 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 is connected to the surrounding wall, the limiting structure comprises a top portion and a bottom portion opposite to the top portion, the bottom wall and the bottom portion are arranged in flush, and the top wall is closer to the diaphragm relative to the top portion.

8. The MEMS microphone of claim 1, wherein, The base comprises 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 is connected to the surrounding wall, the limiting structure comprises a top portion and a bottom portion opposite to the top portion, the top wall is closer to the diaphragm relative to the top portion, and the bottom portion is closer to the diaphragm relative to the bottom wall.

9. The MEMS microphone of claim 1, wherein, The base is integrally formed with the limiting structure.

Images