Diaphragm type sound pressure optical microphone

Abstract

The utility model discloses a diaphragm type sound pressure optical microphone, and belongs to the technical field of microphones. Comprising a microphone shell and a sealing cover, a groove is formed in the upper end of the microphone shell, the groove and the microphone shell are of an integrated structure, pickup holes are formed in the front end and the rear end of the groove, a cavity is defined by the microphone shell and the sealing cover, and a round hole is formed in the bottom of the microphone shell. According to the utility model, the problems of general frequency response characteristic and general noise reduction performance of the microphone in the prior art are solved, and the aperture ratio of the microphone is increased by arranging the two grooves and the pickup holes on the upper end face of the microphone shell, so that external sound can directly act on the optical fiber assembly through the pickup holes, and the noise reduction performance of the microphone is improved. The effective bandwidth of the microphone is improved, and the microphone shell is a metal shell, so that the microphone shell has relatively good structural strength and also has an electromagnetic shielding effect, and the anti-interference capability of the microphone is enhanced.

Description

Technical Field

[0001] The utility model relates to the technical field of microphones, in particular to a diaphragm type sound pressure optical microphone. Background Art

[0002] Acoustic detectors such as microphones and hydrophones are important tools for obtaining information. They are widely used in many fields, such as voice communication, environmental noise monitoring, detection and tracking of aviation and underwater vehicles, bearing fault diagnosis, wind turbine measurement, oil and gas pipeline leakage monitoring, photoacoustic spectroscopy, etc. With the development of technology, people's requirements for the performance of microphones are also constantly improving;

[0003] A Chinese patent with publication number CN212519341U discloses an electret microphone: the patent can increase the proportion of the internal sound cavity of the microphone through an insulating coating and a back pole with a recessed portion stamped in the middle, thereby achieving the effect of increasing sensitivity and signal-to-noise ratio.

[0004] However, although the above technology solves the problem of poor microphone signal-to-noise ratio and sensitivity, it still has the following defects:

[0005] The frequency response characteristics of existing microphones are relatively average, and the noise reduction performance of the microphones is average. Utility Model Content

[0006] The utility model aims to provide a diaphragm type sound pressure optical microphone. By arranging two grooves on the upper end surface of the microphone shell and opening a sound pickup hole, the opening rate of the microphone is increased, so that the external sound can directly act on the optical fiber component through the sound pickup hole, thereby improving the effective bandwidth of the microphone. The groove is in an inverted trapezoidal shape, which can effectively block the external airflow, thereby reducing the impact intensity of the airflow on the microphone diaphragm. The microphone shell is a metal shell, so that the microphone shell has good structural strength and also has the effect of electromagnetic shielding, thereby enhancing the anti-interference ability of the microphone and solving the problems in the prior art.

[0007] To achieve the above-mentioned purpose, the utility model provides the following technical solutions: a diaphragm type sound pressure optical microphone, comprising a microphone shell and a cover, the upper end of the microphone shell is provided with a groove, and the groove and the microphone shell are an integral structure, the front end and the rear end of the groove are provided with pickup holes, the microphone shell and the cover form a cavity, the bottom of the microphone shell is provided with a circular hole, the cover is located on the side of the cavity close to the circular hole, an optical fiber assembly is provided on the cover, and one end of the optical fiber assembly passes through the cover, the back plate and the gasket, the optical fiber assembly is spaced apart from the diaphragm, and a metal coating is provided on the side of the diaphragm facing the optical fiber assembly.

[0008] Preferably, a diaphragm is provided below the sound pickup hole, and an air leakage hole is provided inside the diaphragm.

[0009] Preferably, a gasket is provided below the diaphragm, and a supporting column is provided below the gasket.

[0010] Preferably, a copper ring is provided inside the support column, a back pole plate is provided at the upper end of the copper ring, and a through hole is provided inside the back pole plate.

[0011] Preferably, the groove includes a flat plate portion and a connecting portion, an upper end surface of the flat plate portion is lower than an upper end surface of the microphone housing, both ends of the flat plate portion are connected to the microphone housing through the connecting portion, and the connecting portion is inclined.

[0012] Preferably, the microphone housing is a metal housing.

[0013] Preferably, the surface of the support column is coated with an insulating coating.

[0014] Preferably, the diameter of the air leakage hole is 0.2 mm-2.2 mm.

[0015] Preferably, the sound pickup hole is communicated with the cavity.

[0016] Preferably, the diaphragm consists of a diaphragm and a diaphragm ring, and the diaphragm and the diaphragm ring are connected by glue.

[0017] Compared with the prior art, the beneficial effects of the utility model are as follows:

[0018] 1. The utility model is a diaphragm type sound pressure optical microphone, which increases the opening rate of the microphone by arranging two grooves and opening a pickup hole on the upper end surface of the microphone shell, so that the external sound can directly act on the optical fiber component through the pickup hole, thereby improving the effective bandwidth of the microphone. The groove is in an inverted trapezoidal shape, which can effectively block the external airflow, thereby reducing the impact intensity of the airflow on the microphone diaphragm. The microphone shell is a metal shell, so that the microphone shell has good structural strength and also has the effect of electromagnetic shielding, thereby enhancing the anti-interference ability of the microphone.

[0019] 2. The utility model is a diaphragm type sound pressure optical microphone, which plays a role of noise reduction through the setting of the air release hole. When the diaphragm vibrates, the air pressure inside and outside the diaphragm is relatively balanced, so that the airflow sound is reduced to a lower level. The setting of the through hole can further release the airflow pressure, so that the air pressure inside and outside the diaphragm is more balanced, and the airflow sound is further reduced. The gasket is located between the diaphragm and the back plate, and has an insulating effect. It can effectively prevent the back plate from electrically contacting the diaphragm and change the dielectric constant between the back plate and the diaphragm. The support column can improve the stability of the internal structure of the microphone and make the conductivity between the cover and the back plate better. The insulating coating can prevent short circuits. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the overall structure of the utility model;

[0021] Figure 2 It is a schematic diagram of the overall structure of the utility model when viewed from above;

[0022] Figure 3 This is a schematic diagram of the cross-sectional structure of the microphone housing of the present utility model;

[0023] Figure 4 It is a cross-sectional view of the internal structure of the cavity of the present utility model.

[0024] In the figure: 1. microphone housing; 2. sound pickup hole; 3. groove; 4. cover; 5. copper ring; 6. support column; 7. gasket; 8. diaphragm; 9. back plate; 101. round hole; 301. flat plate; 302. connecting part; 401. optical fiber assembly; 801. vent hole; 901. through hole. DETAILED DESCRIPTION

[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 this field without creative work are within the scope of protection of the utility model.

[0026] In order to solve the technical problem that the frequency response characteristics of the microphone are relatively general and the noise reduction performance of the microphone is generally general in the prior art, please refer to Figure 1-4 , providing the following technical solutions:

[0027] In the present embodiment, a diaphragm type sound pressure optical microphone includes a microphone shell 1 and a cover 4. A groove 3 is provided at the upper end of the microphone shell 1, and the groove 3 and the microphone shell 1 are an integral structure. The groove 3 is formed by stamping and cutting the upper end surface of the microphone shell 1 with a mold. The front and rear ends of the groove 3 are provided with pickup holes 2, and the pickup holes 2 are connected to the cavity as a sound transmission channel. The microphone shell 1 and the cover 4 form a cavity. A circular hole 101 is provided at the bottom of the microphone shell 1. The cover 4 is located on a side of the cavity close to the circular hole 101. An optical fiber assembly 401 is provided on the cover 4, and one end of the optical fiber assembly 401 passes through the cover 4, the back plate 9 and the gasket 7. The optical fiber assembly 401 is spaced apart from the diaphragm 8, and a metal coating is provided on the side of the diaphragm 8 facing the optical fiber assembly 401. The optical fiber assembly 401 includes a transmitting optical fiber and a plurality of receiving optical fibers surrounding the transmitting optical fiber. The end faces of the transmitting optical fiber and the receiving optical fiber are both non-planar to form an optical fiber lens.

[0028] A diaphragm 8 is arranged below the sound pickup hole 2. The diaphragm 8 is composed of a diaphragm and a diaphragm ring. The diaphragm and the diaphragm ring are connected by glue. The diaphragm is glued to the diaphragm ring by glue. When the sound signal enters the sound pickup hole 2, the diaphragm on the diaphragm 8 will vibrate and drive the diaphragm 8 to move. The transmitting optical fiber sends a light signal to the diaphragm. The light signal is reflected by the metal coating. The reflected light signal is received by the receiving optical fiber and transmitted to the photoelectric conversion mechanism to be converted into an electrical signal. The intensity change of the reflected light signal can reflect the vibration amplitude of the diaphragm. In this way, the sound signal is converted into an electrical signal through the conversion of sound, light and electricity. An air vent 801 is arranged inside the diaphragm 8. The aperture of the air vent 801 is 0.2mm-2.2mm. The air vent 801 plays a role in noise reduction. When the diaphragm 8 vibrates, the air pressure inside and outside the diaphragm 8 is relatively balanced, so that the air flow sound is reduced to a lower level.

[0029] It should be noted that the conversion mechanism of the optical microphone includes three parts, namely: an acoustic-mechanical conversion mechanism, a mechanical-optical conversion mechanism, and an optical-electrical conversion mechanism. Among them, the acoustic-mechanical conversion mechanism is the displacement of the membrane caused by sound pressure, and the conversion structure can be manufactured using conventional microphone manufacturing technology. The mechanical-optical conversion mechanism is that the membrane displacement changes the input light intensity coupled to the output optical fiber component 401. The optical-electrical conversion mechanism converts the optical power into an electrical signal through one or more photodiodes. It does not belong to the microphone body of the optical microphone, but is connected to the microphone body through the optical fiber component 401.

[0030] In this embodiment, a gasket 7 is provided under the diaphragm 8. The gasket 7 is located between the diaphragm 8 and the back plate 9 and has an insulating effect. It can effectively prevent the back plate 9 from making electrical contact with the diaphragm 8 and change the dielectric constant between the back plate 9 and the diaphragm 8. A support column 6 is provided under the gasket 7. The surface of the support column 6 is coated with an insulating coating. The support column 6 can improve the stability of the internal structure of the microphone and make the conductivity between the cover 4 and the back plate 9 better. The insulating coating can prevent short circuit.

[0031] In this embodiment, a copper ring 5 is provided inside the support column 6, and a back pole plate 9 is provided at the upper end of the copper ring 5. The copper ring 5 is located between the back pole plate 9 and the cover 4, supporting the structure of the optical microphone, and electrically connecting the cover 4 and the diaphragm 8. A through hole 901 is provided inside the back pole plate 9. The back pole plate 9 is formed by stamping H65 copper, which has a high cost performance. The through hole 901 can further relieve the pressure of the airflow, so that the air pressure inside and outside the diaphragm 8 is more balanced, so that the airflow sound is further reduced, and the sensitivity of the low frequency is reduced.

[0032] In this embodiment, the groove 3 includes a flat portion 301 and a connecting portion 302. The upper end surface of the flat portion 301 is lower than the upper end surface of the microphone housing 1. Both ends of the flat portion 301 are connected to the microphone housing 1 through the connecting portion 302, and the connecting portion 302 is inclined. The groove 3 as a whole is lower than the upper end surface of the microphone housing 1. By setting two grooves 3, the opening rate of the microphone is increased, so that external sounds can directly act on the optical fiber assembly 401 through the pickup hole 2, thereby improving the effective bandwidth of the optical microphone. The groove 3 is in an inverted trapezoidal shape, which can effectively block the external airflow, thereby reducing the impact intensity of the airflow on the microphone diaphragm 8.

[0033] In this embodiment, the microphone housing 1 is a metal housing, so that the microphone housing 1 has good structural strength and also has an electromagnetic shielding effect, thereby enhancing the anti-interference ability of the microphone.

[0034] Working principle: When the optical microphone is used in a wind noise environment, external sounds enter the microphone housing 1 through the sound pickup hole 2. By setting two grooves 3, the opening rate of the microphone is increased, so that external sounds can directly act on the optical fiber component 401 through the sound pickup hole 2, thereby improving the effective bandwidth of the microphone. Since the diaphragm 8 is provided with an air leakage hole 801, the air flow can smoothly pass through the air leakage hole 801 to the back plate 9. When the air flow passes through the through hole 901 of the back plate 9, the through hole 901 can further relieve the pressure of the air flow. When the diaphragm 8 vibrates, the internal and external air pressures of the diaphragm 8 can reach a relative balance, so that the microphone has a certain noise reduction effect.

[0035] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0036] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A diaphragm type sound pressure optical microphone, comprising a microphone housing (1) and a cover (4), characterized in that: The upper end of the microphone housing (1) is provided with a groove (3), and the groove (3) and the microphone housing (1) are an integral structure. The front end and the rear end of the groove (3) are provided with sound pickup holes (2). The microphone housing (1) and the cover (4) form a cavity. The bottom of the microphone housing (1) is provided with a circular hole (101). The cover (4) is located on a side of the cavity close to the circular hole (101). An optical fiber assembly (401) is provided on the cover (4), and one end of the optical fiber assembly (401) passes through the cover (4), the back plate (9) and the gasket (7). The optical fiber assembly (401) is spaced apart from the diaphragm (8), and a metal coating is provided on the side of the diaphragm (8) facing the optical fiber assembly (401).

2. The diaphragm type sound pressure optical microphone according to claim 1, characterized in that: A diaphragm (8) is arranged below the sound pickup hole (2), and an air leakage hole (801) is arranged inside the diaphragm (8).

3. The diaphragm type sound pressure optical microphone according to claim 2, characterized in that: A gasket (7) is arranged below the diaphragm (8), and a support column (6) is arranged below the gasket (7).

4. The diaphragm type sound pressure optical microphone according to claim 3, characterized in that: A copper ring (5) is arranged inside the support column (6), a back plate (9) is arranged at the upper end of the copper ring (5), and a through hole (901) is arranged inside the back plate (9).

5. The diaphragm type sound pressure optical microphone according to claim 1, characterized in that: The groove (3) comprises a flat plate portion (301) and a connecting portion (302); the upper end surface of the flat plate portion (301) is lower than the upper end surface of the microphone housing (1); both ends of the flat plate portion (301) are connected to the microphone housing (1) via the connecting portion (302), and the connecting portion (302) is inclined.

6. The diaphragm type sound pressure optical microphone according to claim 1, characterized in that: The microphone housing (1) is a metal housing.

7. The diaphragm type sound pressure optical microphone according to claim 3, characterized in that: The surface of the support column (6) is coated with an insulating coating.

8. The diaphragm type sound pressure optical microphone according to claim 2, characterized in that: The diameter of the air leakage hole (801) is 0.2 mm-2.2 mm.

9. The diaphragm type sound pressure optical microphone according to claim 1, characterized in that: The sound pickup hole (2) is communicated with the cavity.

10. The diaphragm type sound pressure optical microphone according to claim 2, characterized in that: The diaphragm (8) consists of a diaphragm and a diaphragm ring, and the diaphragm and the diaphragm ring are connected by glue.

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