microphone

Abstract

This microphone provides the ability to switch between unidirectional and omnidirectional patterns without degrading sound quality. [Solution] The microphone 1 comprises a dynamic microphone unit 10 and a condenser microphone unit 90, and a switch 93 allows switching between a dynamic microphone mode in which the dynamic microphone unit is activated, a condenser microphone mode in which the condenser microphone unit is activated, and a hybrid microphone mode in which both the dynamic microphone unit and the condenser microphone unit are activated simultaneously. This makes it possible to switch between unidirectional and omnidirectional modes without degrading sound quality.

Description

Technical Field

[0005]

[0001] The present invention relates to a microphone that converts air pressure into an electrical signal.

Background Art

[0002] Patent Document 1 discloses a variable-direction condenser microphone unit that can be switched between a unidirectional or omnidirectional pattern by opening and closing the rear acoustic terminal of a unidirectional condenser microphone unit. For convenience, the variable-direction condenser microphone unit described in Patent Document 1 is referred to as a "conventional variable-direction microphone unit". Also, a microphone incorporating a conventional variable-direction microphone unit is referred to as a "conventional variable-direction microphone".

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a conventional variable-direction microphone, there is a problem that the sound quality deteriorates compared to a unidirectional dynamic microphone and an omnidirectional condenser microphone in both the unidirectional mode and the omnidirectional mode.

[0005] An object of the present invention is to provide a microphone capable of switching between unidirectional and omnidirectional patterns without deteriorating the sound quality.

Means for Solving the Problems

[0007] According to the present invention, it is possible to provide a microphone that can switch between unidirectional and omnidirectional modes without degrading sound quality. [Brief explanation of the drawing]

[0008] [Figure 1] This is an explanatory diagram of this embodiment, showing a part of the microphone in cross-section along the axial plane. [Figure 2] This is an explanatory diagram of this embodiment, showing the microphone unit in a cross-sectional view along the axial plane. [Figure 3] This is an explanatory diagram of this embodiment, a plan view of an equalizer showing a state in which a condenser microphone unit is housed in the boss portion. [Modes for carrying out the invention]

[0009] One embodiment of the present invention will be described with reference to the attached diagram. For convenience, the direction in which the center line L of the microphone 1 extends (the vertical direction in Figure 1) will be referred to as the "axial direction". As shown in Figure 1, the microphone 1 has a main body case 3, a head case 5, and a microphone unit 7 housed inside the head case 5. The microphone unit 7 comprises a dynamic microphone unit 10 and a condenser microphone unit 90.

[0010] As shown in Figure 2, the dynamic microphone unit 10 includes a diaphragm 11 made of polyester film, a voice coil 15, a yoke assembly 20 (magnetic circuit), and an equalizer 81. The diaphragm 11 has a dome portion 12 formed to protrude axially to one side (the "upward side" in Figure 2), and an outer peripheral portion 13 provided on the outer circumference of the dome portion 12, the cross section of which is formed in an arc shape according to the axial plane (the plane containing the center line L of the microphone 1).

[0011] The voice coil 15 is joined at one axial end (the "upper end" in Figure 2) to the ridge between the dome portion 12 and the outer circumference 13 of the diaphragm 11. The yoke assembly 20 includes a yoke housing 21, a yoke 41, and a magnet 51 (a "neodymium magnet" in this embodiment). The magnet 51 is formed in a disc shape and has an axial hole 52 that penetrates the magnet 51 in the axial direction. A cylindrical shaft portion 23 extending in the axial direction from the center of the circular bottom portion 22 of the yoke housing 21 is inserted into the axial hole 52 of the magnet 51. One pole (the axial side) of the magnet 51 is connected to a disc-shaped pole piece 53. An axial hole 54 is formed in the center of the pole piece 53, through which the shaft portion 23 of the yoke housing 21 penetrates in the axial direction.

[0012] The yoke 41 is formed as a bottomed cylindrical shape with one side open in the axial direction. The yoke 41 has a shaft hole 45 formed in the center of the bottom portion 42, through which the shaft portion 23 of the yoke housing 21 passes. The other pole (the other side in the axial direction) of the magnet 51 is connected to the surface 43 on the axial side of the bottom portion 42 of the yoke 41. The other side in the axial direction of the bottom portion 42 of the yoke 41 (surface 44) abuts against the bottom portion 22 of the yoke housing 31. The yoke 41, magnet 51, and pole piece 53 are fixed to the bottom portion 22 of the yoke housing 21 by a crimped portion 25 formed by heat crimping the tip of the shaft portion 23 of the yoke housing 21, which is made of resin (in this embodiment, "ABS resin"), of the yoke housing 21.

[0013] As a result, a magnetic gap 55 with a certain distance is formed between the axial end of the cylindrical portion 46 of the yoke 41 and the outer circumference of the pole piece 53. The voice coil 15 is inserted into the magnetic gap 55 without contacting the yoke 41 or the pole piece 53. The shaft hole 24 of the shaft portion 23 of the yoke housing 21 opens in the center of the crimped portion 25. A nylon damper 26 is also joined to the axial surface of the crimped portion 25.

[0014] A cylindrical portion 27 extending axially to the other side is formed at the bottom 22 of the yoke housing 21. The cylindrical portion 27 is coupled to a tail member 61 which is formed as a bottomed cylinder with one side open axially. The tail member 61 is made of resin (in this embodiment, "ABS resin"). The outer diameter of the cylindrical portion 63 of the tail member 61 is set to be the same as the outer diameter of the outer circumference of the bottom 22 of the yoke housing 21 (the "sleeve fitting portion 29" described later). The tail member 61 is positioned axially relative to the yoke housing 21 by the end face 30 of the cylindrical portion 27 of the yoke housing 21 contacting the bottom 62 of the tail member 61.

[0015] In this embodiment, the yoke housing 21 and the tail member 61 are screw-connected by screwing together a male thread 28 formed on the outer circumference of the cylindrical portion 27 of the yoke housing 21 and a female thread 65 formed on the inner circumference of the cylindrical portion 63 of the tail member 61. The tail member 61 also has a plurality of passages 64 (eight in this embodiment) that penetrate the bottom portion 62 axially and are equally spaced on a circle centered on the center line of the cylindrical portion 63 (which coincides with the center line L of the microphone 1).

[0016] The dynamic microphone unit 10 has a bottomed cylindrical sleeve 71 that is open on one side in the axial direction. The sleeve 71 has a cylindrical portion 73 into which the aforementioned sleeve fitting portion 29 of the yoke housing 21 and the cylindrical portion 63 of the tail member 61 are fitted (inserted). The yoke housing 21 and the tail member 61 are positioned in the axial direction relative to the sleeve 71 by the bottom portion 62 of the tail member 61 contacting the bottom portion 72 of the sleeve 71. A terminal 16 (see Figure 1) to which the voice coil 15 is connected is provided on the outer circumferential surface of the cylindrical portion 73 of the sleeve 71.

[0017] The sleeve 71 has a plurality of passages 74 (four in this embodiment) that penetrate axially through its bottom 72 and are equally spaced on a circle centered on the centerline of the cylindrical portion 73 (which coincides with the centerline L of the microphone 1). The outside of the dynamic microphone unit 10 (the space on the other axial side) is connected to the space 31 defined by the yoke housing 21 and the tail member 61 via a damper 75 and a double-face filter 76 joined to the other axial side surface of the bottom 72 of the sleeve 71, the plurality of passages 74 formed in the bottom 72 of the sleeve 71, and the plurality of passages 64 formed in the bottom 62 of the tail member 61. The space 31 is also connected to the space 14 on the other axial side of the diaphragm 11 via the axial hole 24 of the shaft portion 23 of the yoke housing 21 and the damper 26.

[0018] Multiple grooves 77 (seven in this embodiment) extending in the axial direction are formed on the outer circumference of the sleeve 71. On the other hand, multiple passages 33 corresponding to each groove 77 (seven in this embodiment) are formed in the flange portion 32 formed at one end of the yoke housing 21 on the axial side. Each groove 77 communicates with the space 14 on the other axial side of the diaphragm 11 via the corresponding passage 33, forming the rear acoustic terminal of the dynamic microphone unit 10. A brass shaft member 66, which is insert-molded into the tail member 61, is inserted through a shaft hole 78 formed in the center of the bottom portion 72 of the sleeve 71. The sleeve 71, and thus the microphone unit 7, is fixed to the head case 5 using the female threads 67 formed on the shaft member 66.

[0019] As shown in FIG. 2 or FIG. 3, the equalizer 81 is formed in a disk shape. The equalizer 81 is a molded part made of resin (in this embodiment, "ABS resin"), like the yoke housing 21, the tail member 61, and the sleeve 71. On the other axial side of the equalizer 81, a recess 82 for accommodating the diaphragm 11 is formed. At the center of the recess 82, a reverse spherical recess 83 having a certain distance from the dome portion 12 of the diaphragm 11 is formed. Note that on one axial side of the equalizer 81, a groove 88 for passing a cable (not shown) connected to an electrode (not shown) of the condenser microphone unit 90 is formed.

[0020] The equalizer 81 has a plurality (in this embodiment, "12") of passages 84 penetrating the bottom surface of the recess 82 in the axial direction. The plurality of passages 84 constitute the front acoustic terminals of the dynamic microphone unit 10. The plurality of passages 84 are arranged so as to face the outer peripheral portion 13 of the diaphragm 11. The equalizer 81 is arranged coaxially with the center line L of the microphone 1 and has a boss portion 85 protruding on one axial side. On one axial side of the equalizer 81, a disk-shaped filter 86 having a hole 87 into which the boss portion 85 is inserted at the center is attached so as to cover the plurality of passages 84. The center on one axial side of the equalizer 81, in other words, the bottom inside the boss portion 85, is formed in a spherical shape corresponding to the recess 83.

[0021] The condenser microphone unit 90 is configured as a capacitor by interposing a spacer (not shown) between a diaphragm (not shown) formed by a conductive film and a back plate (not shown) having an electret layer formed on its surface within a cylindrical housing 91. Here, an existing condenser microphone unit is applied to the condenser microphone unit 90. Therefore, for the sake of brevity of the description in the specification, detailed description of the condenser microphone unit 90 is omitted.

[0022] The condenser microphone unit 90 is disposed inside the boss portion 85 of the equalizer 81. As a result, the condenser microphone unit 90 is disposed directly above the dome portion 12 of the diaphragm 11 of the dynamic microphone unit 10. Also, the condenser microphone unit 90 is disposed coaxially with respect to the center line L of the microphone 1. As a result, the condenser microphone unit 90 is disposed coaxially with the dynamic microphone unit 10.

[0023] The condenser microphone unit 90 is supported by a plurality (in this embodiment, "eight") of dampers 95 provided between the housing 91 and the boss portion 85 of the equalizer 81. The plurality of dampers 95 extend in the axial direction and are arranged at regular intervals in the circumferential direction of the housing 91 and the boss portion 85. The damper 95 is constituted by, for example, anti-vibration rubber. Note that the damper 95 is not intended to be limited to the above shape and material, and any component may be used as long as it can suppress the transmission of the impact (vibration) input to the dynamic microphone unit 10 to the condenser microphone unit 90. Also, in FIG. 2, the end surface of the condenser microphone unit 90 and the boss portion 85 of the equalizer 81 are flush with each other, but the condenser microphone unit 90 may be configured to protrude from the end surface of the boss portion 85 of the equalizer 81.

[0024] In the present embodiment, the microphone 1 has a switch 93 (see FIG. 1) for switching between a dynamic microphone mode for activating the dynamic microphone unit 10, a condenser microphone mode for activating the condenser microphone unit 90, and a hybrid microphone mode for simultaneously activating the dynamic microphone unit 10 and the condenser microphone unit 90. Here, an existing circuit is applied to the circuit for switching the mode of the microphone 1. Therefore, in order to simplify the description of the specification, a detailed description of the circuit for switching the mode of the microphone 1 is omitted.

[0025] As shown in Figure 1 or Figure 2, a damper 35, made of, for example, Papillon®, is attached to the outer circumference of the other axial end of the sleeve 71 by adhesive or the like. In addition, a nylon damper 36 is attached to the outer circumference of one axial side of the sleeve 71, the outer circumference of the flange portion 32 of the yoke housing 21, and the outer circumference of the equalizer 81 by adhesive or the like. Furthermore, a damper 37, made of, for example, Papillon®, is attached to the other axial side surface of the bottom portion 72 of the sleeve 71 so as to cover a plurality of passages 74. Note that the dampers 35 and 36 have holes 38 that communicate with grooves 77 (rear acoustic terminals) formed in the sleeve 71.

[0026] Conventional variable-directional microphones have the problem of degraded sound quality in both unidirectional and omnidirectional modes compared to unidirectional dynamic microphones and omnidirectional condenser microphones.

[0027] In contrast, in this embodiment, the (variable directivity) microphone 1 is configured by arranging the condenser microphone unit 90 inside the boss portion 85 of the equalizer 81 of the dynamic microphone unit 10. Furthermore, in this embodiment, a switch 93 is configured to switch between a unidirectional mode in which the dynamic microphone unit 10 is activated, an omnidirectional mode in which the condenser microphone unit 90 is activated, and a hybrid mode in which both the dynamic microphone unit 10 and the condenser microphone unit 90 are activated simultaneously.

[0028] According to this embodiment, a unidirectional dynamic microphone unit 10 is used in unidirectional mode, and an omnidirectional condenser microphone unit 90 is used in omnidirectional mode, so it is possible to switch between unidirectional and omnidirectional modes without degrading sound quality. In this embodiment, since the condenser microphone unit 90 is arranged coaxially with respect to the dynamic microphone unit 10, it is possible to suppress disturbances in the directional characteristics (off-axis characteristics) between the unidirectional dynamic microphone unit 10 and the omnidirectional condenser microphone unit 90. In this embodiment, the condenser microphone unit 90 is positioned in the center of the equalizer 81 of the dynamic microphone unit 10. In other words, the condenser microphone unit 90 is positioned directly above the dome portion 12 of the diaphragm 11 of the dynamic microphone unit 10. This minimizes the phase difference between the sound waves reaching the dynamic microphone unit 10 and the sound waves reaching the condenser microphone unit 90. Furthermore, since the dynamic microphone unit 10 and the condenser microphone unit 90 are integrated into a single structure, it is possible to avoid increasing the size of the microphone 1. [Explanation of symbols]

[0029] 1 microphone, 10 dynamic microphone units, 90 condenser microphone units

Claims

1. It comprises a dynamic microphone unit and a condenser microphone unit. Microphone.

2. A microphone according to claim 1, The condenser microphone unit is arranged coaxially with the dynamic microphone unit. Microphone.

3. A microphone according to claim 1 or 2, The dynamic microphone unit comprises a diaphragm and a disc-shaped equalizer positioned opposite the diaphragm. The condenser microphone unit is housed inside the boss portion located in the center of the equalizer. Microphone.

4. A microphone according to claim 1, The device includes a switch to select between a dynamic microphone mode that activates the dynamic microphone unit, a condenser microphone mode that activates the condenser microphone unit, and a hybrid microphone mode that activates both the dynamic microphone unit and the condenser microphone unit simultaneously. Microphone.

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