Directional mems microphone

Abstract

The application discloses a directional MEMS microphone, comprising: a circuit board and a metal back cover, which enclose a first cavity and a second cavity; an omnidirectional microphone unit, comprising a first MEMS chip and a first ASIC chip arranged in the first cavity, and a first sound hole communicating the first cavity with the outside; a directional microphone unit, comprising a second MEMS chip and a second ASIC chip arranged in the second cavity, and a second sound hole and a third sound hole communicating the second cavity with the outside; wherein the omnidirectional microphone unit and the directional microphone unit are connected in series. The application has the following advantages: 1. a directional microphone unit is formed by using a MEMS element, an omnidirectional microphone unit is formed at the same time, and the two are connected in series, so that better effect than a single directional microphone can be achieved; 2. the structure is more compact, and the two microphone units are relatively fixed in position.

Description

Technical Field

[0001] This application relates to the field of microphone technology, specifically to a directional MEMS microphone. Background Technology

[0002] MEMS (Micro-electromechanical Systems) microphones are microphones manufactured based on MEMS technology. Compared with traditional microphones, MEMS microphones can be manufactured using surface mount technology, can withstand high reflow soldering temperatures, are easily integrated with CMOS (Complementary Metal-Oxide-Semiconductor) technology and other audio circuits, and have improved noise cancellation performance and good RF (Radio Frequency) and EMI (Electromagnetic Interference) suppression capabilities. They are currently widely used in smart terminal fields such as voice calls and intelligent voice interaction.

[0003] Microphones come in two types based on directionality: omnidirectional and directional. Directional microphones only pick up sound from a specific direction. However, most MEMS microphones currently on the market are omnidirectional. Therefore, providing a MEMS microphone with excellent directivity has become an urgent technical problem to be solved. Utility Model Content

[0004] The main technical problem addressed in this application is to provide a directional MEMS microphone.

[0005] This application provides a directional MEMS microphone, including:

[0006] The circuit board and the metal back cover together form the first cavity and the second cavity;

[0007] An omnidirectional microphone unit includes a first MEMS chip and a first ASIC chip disposed in the first cavity, and a first sound hole connecting the first cavity to the outside.

[0008] The directional microphone unit includes a second MEMS chip and a second ASIC chip disposed in the second cavity, as well as a second sound hole and a third sound hole connecting the second cavity to the outside.

[0009] The omnidirectional microphone unit and the directional microphone unit are connected in series.

[0010] In some alternative implementations, the first MEMS chip and the first ASIC chip are mounted on the circuit board, and the first ASIC chip is connected to the first MEMS chip and the circuit board respectively via wires; the second MEMS chip and the second ASIC chip are mounted on the circuit board, and the second ASIC chip is connected to the second MEMS chip and the circuit board respectively via wires.

[0011] In some alternative embodiments, the first and second acoustic holes are through holes formed on the metal back cover, and the third acoustic hole is an acoustic hole formed on the circuit board.

[0012] In some alternative implementations, the third acoustic aperture overlaps with the second MEMS chip in the vertical direction.

[0013] In some alternative embodiments, the diameter of the third acoustic hole is smaller than the diameter of the second acoustic hole.

[0014] In some alternative embodiments, the metal back cover has a baffle at approximately the middle position, the baffle dividing the cavity formed by the metal back cover and the circuit board into a first cavity and a second cavity.

[0015] In some alternative implementations, the first acoustic hole is closer to the edge of the metal back cover relative to the baffle, and the second cavity is closer to the edge of the metal back cover relative to the baffle.

[0016] In some alternative implementations, the metal back cover and the circuit board are connected by a solder seal.

[0017] In some alternative implementations, the volume of the first cavity and the volume of the second cavity are substantially equal.

[0018] In some alternative implementations, the first MEMS chip and the second MEMS chip are close to each other, while the first ASIC chip and the second ASIC chip are far from each other.

[0019] As described above, this application proposes a directional MEMS microphone. From the above technical solutions, it can be seen that the embodiments of this application have the following advantages:

[0020] 1. By utilizing MEMS components to form a directional microphone unit and an omnidirectional microphone unit, and connecting them in series, the output signal can be generated by adjusting the frequency response. This achieves better results than a single directional microphone, such as a flatter low-frequency response. It also provides stronger noise shielding in various noisy recording environments. Low frequencies are not lost during recording, resulting in a fuller and richer bass sound.

[0021] 2. The circuit board and metal back cover are used to form an integrated structure including two cavities to accommodate two microphone units, making the structure more compact and fixing the relative positions of the two microphone units, which is more conducive to signal processing. Attached Figure Description

[0022] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments and the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the longitudinal cross-sectional structure of a directional MEMS microphone according to an embodiment of this application.

[0024] Reference numerals: 11: Circuit board; 12: Metal back cover; 121: Barrier wall; 13: First cavity; 14: Second cavity; 15: First MEMS chip; 16: First ASIC chip; 17: Second MEMS chip; 18: Second ASIC chip; 19: Wire; 20: First sound inlet; 21: Second sound inlet; 22: Third sound inlet. Detailed Implementation

[0025] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present application.

[0026] The terms "first," "second," "third," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish different objects, not to describe a specific order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or apparatuses.

[0027] The following detailed descriptions will be provided through specific embodiments.

[0028] refer to Figure 1 This application provides a directional MEMS microphone, comprising:

[0029] The circuit board 11 and the metal back cover 12 enclose each other to form a first cavity 13 and a second cavity 14;

[0030] The omnidirectional microphone unit includes a first MEMS chip 15 and a first ASIC chip 16 disposed in the first cavity 13, and a first sound hole 20 connecting the first cavity 13 with the outside world;

[0031] The directional microphone unit includes a second MEMS chip 17 and a second ASIC chip 18 disposed in the second cavity 14, and a second sound hole 21 and a third sound hole 22 connecting the second cavity 14 with the outside world.

[0032] The omnidirectional microphone unit and the directional microphone unit are connected in series.

[0033] Here, the first MEMS chip 15 and the first ASIC chip 16 are mounted on the circuit board 11. The first ASIC chip 16 can be connected to the first MEMS chip 15 and the circuit board 11 by wire bonding. The second MEMS chip 17 and the second ASIC chip 18 are mounted on the circuit board 11. The second ASIC chip 18 can be connected to the second MEMS chip 17 and the circuit board 11 by wire bonding.

[0034] Here, the first sound hole 20 and the second sound hole 21 can be through holes formed on the metal back cover 12, and the third sound hole 22 can be through holes formed on the circuit board 11.

[0035] Here, the third sound hole 22 and the second MEMS17 chip can overlap in the vertical direction to achieve better sound reception.

[0036] In some alternative embodiments, the diameter of the third acoustic hole 22 is smaller than the diameter of the second acoustic hole 21.

[0037] In some alternative embodiments, the metal back cover 12 has a baffle at approximately the middle position, which divides the cavity formed by the metal back cover 12 and the circuit board 11 into a first cavity 13 and a second cavity 14.

[0038] In some alternative implementations, the first sound hole 20 is closer to the edge of the metal back cover 12 relative to the baffle, and the second cavity 14 is closer to the edge of the metal back cover 12 relative to the baffle.

[0039] In some alternative implementations, the metal back cover 12 and the circuit board 11 are connected by a solder seal.

[0040] In some alternative embodiments, the volume of the first cavity 13 is substantially equal to the volume of the second cavity 14.

[0041] In some alternative implementations, the first MEMS chip 15 and the second MEMS chip 22 are close to each other, while the first ASIC chip 15 and the second ASIC chip 18 are far apart from each other.

[0042] As described above, this application discloses a directional MEMS microphone. Its metal back cover 12 adopts an M-shaped structure, forming two cavities that house components to form two microphone units. One microphone unit has a single-sided sound inlet (omnidirectional) with a circular directional pattern, equivalent to the pressure principle. The other microphone unit has two-sided sound inlet holes (bidirectional) with a figure-eight directional pattern, equivalent to the pressure difference principle. The circuitry is connected in series.

[0043] The technical solution of this application has been described in detail above through specific embodiments. In the above embodiments, the descriptions of each embodiment have their own emphasis, and for parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0044] It should be understood that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Those skilled in the art can modify the technical solutions described in the above embodiments, or make equivalent substitutions for some of the technical features; however, these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and protection scope of the technical solutions of the embodiments of this application.

Claims

1. A directional MEMS microphone, characterized in that, include: The circuit board and the metal back cover together form the first cavity and the second cavity; An omnidirectional microphone unit includes a first MEMS chip and a first ASIC chip disposed in the first cavity, and a first sound hole connecting the first cavity to the outside. The directional microphone unit includes a second MEMS chip and a second ASIC chip disposed in the second cavity, as well as a second sound hole and a third sound hole connecting the second cavity to the outside. The omnidirectional microphone unit and the directional microphone unit are connected in series.

2. The directional MEMS microphone according to claim 1, characterized in that, The first MEMS chip and the first ASIC chip are mounted on the circuit board, and the first ASIC chip is connected to the first MEMS chip and the circuit board respectively through wires; The second MEMS chip and the second ASIC chip are mounted on the circuit board, and the second ASIC chip is connected to the second MEMS chip and the circuit board respectively through wires.

3. The directional MEMS microphone according to claim 1, characterized in that, The first and second sound holes are through holes formed on the metal back cover, and the third sound hole is a sound hole formed on the circuit board.

4. The directional MEMS microphone according to claim 3, characterized in that, The third acoustic hole overlaps with the second MEMS chip in the vertical direction.

5. The directional MEMS microphone according to claim 4, characterized in that, The diameter of the third acoustic hole is smaller than that of the through hole of the second acoustic hole.

6. The directional MEMS microphone according to claim 1, characterized in that, The metal back cover has a baffle wall at approximately the middle position, which divides the cavity formed by the metal back cover and the circuit board into a first cavity and a second cavity.

7. The directional MEMS microphone according to claim 6, characterized in that, The first acoustic hole is closer to the edge of the metal back cover relative to the baffle, and the second cavity is closer to the edge of the metal back cover relative to the baffle.

8. The directional MEMS microphone according to claim 1, characterized in that, The metal back cover and the circuit board are connected by a solder seal.

9. The directional MEMS microphone according to claim 1, characterized in that, The volume of the first cavity and the volume of the second cavity are substantially equal.

10. The directional MEMS microphone according to claim 1, characterized in that, The first MEMS chip and the second MEMS chip are close to each other, while the first ASIC chip and the second ASIC chip are far apart from each other.

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