Field of the Invention
The present invention relates to a microphone device, and in particular it relates to a directional microphone device which supports different sensitivities.
Description of the Related Art
Currently, most microphone devices are capacitive microphones in which micro-electro mechanical system (MEMS) microphones are widely used. A MEMS microphone uses MEMS, which can integrate electronic, electrical, and mechanical functions into a single device. Therefore, a MEMS microphone may have the advantages of a small size, low power consumption, easy packaging, and resistance to interference.
In general, a directional microphone has a better signal-to-noise ratio and an improved performance in the microphone device's acoustic signal processing. If the dynamic range of the microphone increases, then the microphone can correctly receive a wider range of volume. Therefore, it is desirable to have a directional microphone device which supports a wide dynamic range.
A detailed description is given in the following embodiments with reference to the accompanying drawings.
The present disclosure provides a microphone device. The microphone device comprises a first chamber, a second chamber, a first acoustic sensor, a second acoustic sensor and a sound transmission device. The first chamber comprises a first acoustic port. The second chamber comprises a second acoustic port. The first acoustic sensor is arranged in the first chamber. The second acoustic sensor is arranged in the second chamber. The sound transmission device is coupled to the first chamber and the second chamber. The sound transmission device comprises a third acoustic port, a fourth acoustic port, a first acoustic tube and a second acoustic tube. The first acoustic tube communicates with the first acoustic port and the third acoustic port, and the second acoustic tube communicates with the second acoustic port and the fourth acoustic port. The directivity of the microphone device is determined based on the length difference between the first acoustic tube and the second acoustic tube or determined based on the cross-sectional area difference between the first acoustic tube and the second acoustic tube. The sensitivity difference between the first acoustic sensor and the second acoustic sensor is determined based on the length difference or determined based on the cross-sectional area difference.
The present disclosure provides a control method of a microphone device, comprising: determining the sensitivity difference between a first acoustic sensor inside a first chamber of the microphone device and a second acoustic sensor inside a second chamber of the microphone device based on the length difference between a first acoustic tube and a second acoustic tube of a sound transmission device of the microphone device or based on the cross-sectional area difference between the first acoustic tube and the second acoustic tube; and determining directivity of the microphone device based on the length difference or the cross-sectional area difference.
The sound transmission device is coupled to the first chamber and the second chamber. The first acoustic tube communicates with a first acoustic port of the first chamber and a third acoustic port of the sound transmission device, and the second acoustic tube communicates with a second acoustic port of the second chamber and a fourth acoustic port of the sound transmission device.
The present disclosure can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein:
The following description is of the best-contemplated mode of carrying out the invention. This description is made for the purpose of illustrating the general principles of the invention and should not be taken in a limiting sense. The scope of the invention is best determined by reference to the appended claims.
The acoustic sensor 110 includes the diaphragm 111, and the acoustic sensor 120 includes the diaphragm 121. The sound transmission device 150 coupled to the chambers CH1 and CH2 includes the acoustic tube 151, the acoustic tube 152, the acoustic port 153 and the acoustic port 154. The acoustic tube 151 communicates with the acoustic port 130 and the acoustic port 153. The acoustic tube 152 communicates with the acoustic port 140 and the acoustic port 154.
In some embodiments, the length difference between the acoustic tubes 151 and 152 or the cross-sectional area difference between the acoustic tube 151 and the acoustic tube 152 can determine directivity of the microphone device 100. In some embodiments, the length difference between the acoustic tubes 151 and 152 or the cross-sectional area difference between the acoustic tube 151 and the acoustic tube 152 (e.g., the volume difference between the acoustic tubes 151 and 152) can determine the sensitivity difference between the acoustic sensors 110 and 120.
As shown in
In some embodiments, the size of the diaphragm 111 and the size of the diaphragm 121 are different, so the rigidity of the diaphragm 111 and the rigidity of the diaphragm 121 are also different, which makes the sensitivity of the acoustic sensor 110 different from the sensitivity of the acoustic sensor 120 and increases the dynamic range of the microphone device 100. In some embodiments, the acoustic tube 151 and the acoustic tube 152 may be different lengths or have different cross-sectional areas. In such cases, when the sound wave is transmitted to the diaphragm 111 and the diaphragm 121 through the acoustic tube 151 and the acoustic tube 152, respectively, the sound degradation caused by the acoustic tube 151 and that caused by the acoustic tube 152 are different, which makes the sensitivity of acoustic sensor 110 different from the sensitivity of the acoustic sensor 120 and increases the dynamic range of the microphone device 100.
Specifically, one embodiment related to the microphone device described above is illustrated in
The chamber CH21 and chamber CH22 are formed by the microphone cover 201 and the circuit board 202 which are coupled to each other. The sound transmission device 210 is formed by the circuit board 202. The chamber CH21 includes the acoustic port O1, and the chamber CH22 includes the acoustic port O2. The acoustic sensor M1 and the integrated circuit C1 are placed inside the chamber CH21, and the acoustic sensor M2 is placed inside the chamber CH22. The circuit board 202 includes the acoustic tube S21, the acoustic tube S22, the acoustic port O3, and the acoustic port O4. The acoustic tube S21 communicates with the acoustic port O1 and the acoustic port O3, and the acoustic tube S22 communicates with the acoustic port O2 and the acoustic port O4.
As shown in
The integrated circuit C1 is coupled to the acoustic sensor M1 and the acoustic sensor M2 to provide voltage to the acoustic sensors M1 and M2 and process the signals received from the acoustic sensors M1 and M2. In some embodiments, the signals received from the acoustic sensors M1 and M2 respectively correspond to the vibrations of the diaphragms D1 and D2 in response to the sound. In some embodiments, the integrated circuit C1 may provide different respective voltages to the acoustic sensor M1 and the acoustic sensor M2, which makes the distance between the diaphragm D1 and the back-plate (not shown in
In this embodiment, the length L21 of the acoustic tube S21 is shorter than the length L22 of the acoustic tube S22. Accordingly, the sound path (or propagation path) of the sound transmitted to the diaphragm D1 through the acoustic tube S21 is shorter than the sound path of the sound transmitted to the diaphragm D2 through the acoustic tube S22. Based on the distance d1 and the different length between the acoustic tube S21 and the acoustic tube S22, the sound may substantially reach both the diaphragm D1 and the diaphragm D2 at the same time that the sound is substantially transmitted in a specific direction. In such cases, the acoustic tube S21, the acoustic tube S22, and the distance d1 may determine the directivity of the microphone device 200A.
Since the sound path of the acoustic tube S22 is longer than the sound path of the acoustic tube S21, the sound degradation caused by the acoustic tube S22 is greater than the sound degradation caused by the acoustic tube S21. In such cases, the sensitivity of the acoustic sensor M1 may be better than the sensitivity of the acoustic sensor M2 (i.e., the acoustic sensor M1 is more sensitive than the acoustic sensor M2), which makes the microphone device 200A support two different sensitivities and makes the microphone device 200A have a wider dynamic range. Therefore, the sound transmission device 210 including the acoustic tubes S21 and S22 can be utilized to determine the directivity of the microphone device 200A and make the microphone device 200A have a wide dynamic range.
In some embodiments, the acoustic tube S21 and the acoustic tube S22 may have different cross-sectional areas. Since different cross-sectional areas cause different sound degradations, the dynamic range and the directivity of the microphone device 200A can be designed based on different cross-sectional areas of the acoustic tube S21 and the acoustic tube S22.
In some embodiments, the circuit board 202 may include multiple layers. In some embodiments, the circuit board 202 may consist of different circuit boards. For example, the acoustic port O1 and acoustic port O2 are placed on a first circuit board, and the acoustic port O3 and acoustic port O4 are placed on a second circuit board which coupled to the first circuit board.
If the length L22 of the acoustic tube S22 becomes longer, then the sound path in the acoustic tube S22 also become longer, which increases the sound degradation caused by the acoustic tube S22, as shown in
In some embodiments, the directivity of the microphone device 200A can be designed based on the difference between the length L21 of the acoustic tube S21 and the length L22 of the acoustic tube S22, as shown in
In some embodiments, the directivity of the microphone device 200A can be designed based on the cross-sectional area difference between the acoustic tube S21 and the acoustic tube S22, as shown in
The chamber CH71 and chamber CH72 are formed by the microphone cover 702 and the circuit board 703 which are coupled to each other. The sound transmission device 710 is formed by the rubber structure 701. The chamber CH71 includes the acoustic port O71, and the chamber CH72 includes the acoustic port O72. The acoustic sensor M1 and the integrated circuit C1 are placed inside the chamber CH71, and the acoustic sensor M2 is placed inside the chamber CH72. The rubber structure 701 includes the acoustic tube S71, the acoustic tube S72, the acoustic port O73, and the acoustic port O74. The acoustic tube S71 communicates with the acoustic port O71 and the acoustic port O73, and the acoustic tube S72 communicates with the acoustic port O72 and the acoustic port O74.
As shown in
In this embodiment, the length L71 of the acoustic tube S71 is shorter than the length L72 of the acoustic tube S72. Accordingly, the sound path (or propagation path) of the sound transmitted to the diaphragm D1 through the acoustic tube S71 is shorter than the sound path of the sound transmitted to the diaphragm D2 through the acoustic tube S72. Based on the distance d2 and the different length between the acoustic tube S71 and the acoustic tube S72, the sound may substantially reach both the diaphragm D1 and the diaphragm D2 at the same time that the sound is substantially transmitted in a specific direction. In such cases, the acoustic tube S71, the acoustic tube S72, and the distance d2 may determine the directivity of the microphone device 700A.
Since the sound path of the acoustic tube S72 is longer than the sound path of the acoustic tube S71, the sound degradation caused by the acoustic tube S72 is greater than the sound degradation caused by the acoustic tube S71. In such cases, the sensitivity of the acoustic sensor M1 may be better than the sensitivity of the acoustic sensor M2, which makes the microphone device 700A support two different sensitivities and makes the microphone device 700A have a wider dynamic range. Therefore, the sound transmission device 710 including the acoustic tubes S71 and S72 can be utilized to determine the directivity of the microphone device 700A and make the microphone device 700A have a wide dynamic range.
In some embodiments, the acoustic tube S71 and the acoustic tube S72 may have different cross-sectional areas. Since different cross-sectional areas cause different sound degradations, the dynamic range and the directivity of the microphone device 700A can be designed based on different cross-sectional areas of the acoustic tube S71 and the acoustic tube S72.
The chamber CH71B includes the acoustic port O71B, and the chamber CH72B includes the acoustic port O72B. The acoustic sensor M1 and the integrated circuit C1 are placed inside the chamber CH71B, and the acoustic sensor M2 is placed inside the chamber CH72B. The chamber CH71B and chamber CH72B are formed by the microphone cover 704 and the circuit board 703 which are coupled to each other. The sound transmission device 720 is formed by the microphone cover 704. The microphone cover 704 includes the acoustic tube S71B, the acoustic tube S72B, the acoustic port O73B, and the acoustic port O74B. The acoustic tube S71B communicates with the acoustic port O71B and the acoustic port O73B, and the acoustic tube S72B communicates with the acoustic port O72B and the acoustic port O74B.
As shown in
In this embodiment, the length L71B of the acoustic tube S71B is shorter than the length L72B of the acoustic tube S72B. As described in
In some embodiments, the acoustic tube S71B and the acoustic tube S72B may have different cross-sectional areas. Since different cross-sectional areas cause different sound degradations, the dynamic range and the directivity of the microphone device 700B can be designed based on different cross-sectional areas of the acoustic tube S71B and the acoustic tube S72B.
While the invention has been described by way of example and in terms of the preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. On the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.
This application claims the benefit of U.S. Provisional Application No. 62/393,249, filed on Sep. 12, 2016, the entirety of which is incorporated by reference herein.
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8638955 | Takano | Jan 2014 | B2 |
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Number | Date | Country | |
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20180077489 A1 | Mar 2018 | US |
Number | Date | Country | |
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62393249 | Sep 2016 | US |