JP2579190Y2 - Condenser microphone - Google Patents

Description

[Detailed description of the invention]

[0001]

Respect BACKGROUND OF THE devised condenser microphone, and say in particular detail, about the condenser microphone to lower the occurrence of wind noise to reduce the pressure difference between the front and rear of the diaphragm by the wind.

[0002]

2. Description of the Related Art A condenser microphone in which a change in capacitance between a diaphragm and a back electrode, which is a fixed electrode located behind the diaphragm, is taken out as a change in voltage due to the vibration of the diaphragm is particularly an electret material. The need for a DC high-voltage power supply is eliminated with the advent of the microphone unit, and the microphone unit is easily reduced in size and weight, and is widely used from business use to general use.

An example of such a condenser microphone unit will be described with reference to FIG. 4. An opening of a hollow insulating seat 1 made of an insulating material and having an opening at one end has a front surface slightly extending from the tip of the opening. A disc-shaped back electrode plate 2 is fitted via a spacer 3 so as to protrude. A diaphragm 5 whose peripheral edge is supported by a ring 4 is fixed to the front end of the opening of the insulating seat 1 by a spacer 6 with a gap from the back electrode plate 2. Reference numeral 7 denotes an acoustic resistance material that covers the through hole 8 formed at the bottom of the insulating seat 1, and the lower surface thereof is supported by a support plate 9. Reference numeral 10 denotes a connection terminal for connecting the back electrode plate 2 to an impedance converter (not shown). The through hole 8 is also formed in the back electrode plate 2, and the through hole 8 side of the insulating seat 1 becomes a rear acoustic terminal. These components are fixed in a unit case 11 made of metal such as soft aluminum by caulking by curling or the like. An opening 12 for sound pickup is formed on the front surface of the unit case 11,
These openings 12 serve as front acoustic terminals.

[0004] In such a condenser microphone, a pressure difference occurs due to wind before and after the diaphragm 5 of the microphone unit, and this pressure difference becomes wind noise. This wind noise is frequently generated in a unidirectional microphone by an omnidirectional microphone. As means for reducing such wind noise, for example, a front acoustic terminal is formed by connecting an opening 12 at the front center of a unit case 11 which is a front acoustic terminal and a through hole 8 of the insulating seat 1 with an acoustic tube. It has been proposed to reduce the pressure difference due to wind between the terminal side and the rear acoustic terminal side.

[0005]

However, since such an acoustic tube is mounted on the outer diameter of the microphone unit, the outermost diameter increases accordingly, which hinders miniaturization and increases the cost. There is a drawback that can not be obtained.

Therefore, the purpose of this invention is to make a simple improvement to the conventional condenser microphone so that the front sound is improved.
Leakage from the sound terminal to the gap between the diaphragm and back plate
A passage as the shortest, is to provide a condenser microphone that is adapted to reduce the wind noise to reduce the pressure difference between the front acoustic terminal and a rear acoustic terminal without increasing the outer diameter.

[0007]

Means for Solving the Problems To achieve the above object,
Therefore , this invention is a unit with a front acoustic terminal on the front.
While holding the case and the ring,
Diaphragm located on the front acoustic terminal side of the
The plate is supported, and the back electrode plate is
Spacing so as to face the diaphragm with a predetermined gap
And an insulating seat disposed on the ring side via a
A rear acoustic terminal is provided at the rear of the insulating seat, and
A gap between the diaphragm and the back plate and the front acoustic end
Capacitors with air leakage paths between them
In the microphone, the air leakage path is provided by the unit.
Interposed between the sound-collecting surface side inner peripheral surface of the knit case and the ring
A first passage consisting of a gap in a wire mesh
A second portion between the outer peripheral surface and the inner peripheral surface on the side surface of the unit case.
Two passages, formed between the insulating seat and the ring
A third passage, the third passage, the diaphragm and the back electrode plate
Provided on the back electrode plate so as to communicate with the gap between them
And a notch .

[0008]

With the above arrangement, even if there is a pressure difference between the front acoustic terminal and the rear acoustic terminal, the air on the high pressure side can flow into the low pressure side through the leak passage. The difference is small, and the wind noise can be reduced. In this case, since the leakage path is formed in the unit case, rather also the unit case itself as larger, also the shortest der distance of leakage paths
Therefore, an excellent response can be obtained.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. Note that the same reference numerals are given to the same components as those in the above-described conventional example, and the detailed description thereof will be omitted.

As in the prior art , the back electrode plate 2 has a plurality of through holes 8.
In the present invention, a rectangular notch 21 extending inward is formed in a part of the periphery of the back electrode plate 2. The notch 21 as shown in FIG. 3, has a length that extends further inward from the inner circumference side of the spacer 6 located thereon.

An air-permeable wire mesh 22 is interposed between the ring 4 supporting the diaphragm 5 and the inner peripheral surface of the unit case 11 on the sound collecting surface side . In this embodiment, a wire mesh having a mesh of about 100 mesh formed with a wire having a diameter of about 0.1 mm is used.

The depth of the concave portion for supporting the spacer 3 and the back electrode plate 2 of the insulating seat 1 is set to be long enough to form a gap between the outer peripheral lower surface of the spacer 6 and the outer peripheral upper surface of the insulating seat 1. Is formed.

Thus, the unit case 11 has
Of the wire mesh 22 from the opening 12 of the first passage A
And the inner peripheral surface on the side surface of the unit case 11 and the outside of the ring 6.
A gap 23 (second passage B) formed by the peripheral surface;
6, a third passage C between the lower surface of the insulating member 6 and the insulating seat 1;
1 and an air leakage passage extending to the back surface of the diaphragm 5 is formed.
It is.

As described above, according to the present invention, the wire mesh 2 is inserted through the opening 12 of the unit case 11 which is the front acoustic terminal.
Some of the 2 applied as the diaphragm 5 the air is first above
1st passage A, 2nd passage B, 3rd passage C, and notch 21
Through the back plate 2 and the insulating plate 1
Flow through each through hole 8 to the rear terminal of the microphone unit, so that the shortest leakage path to the diaphragm is formed.
Since the air on the high pressure side can quickly flow into the low pressure side, the pressure difference becomes small and the wind noise can be reduced.

5 (a) and 5 (b) show wind noise characteristics measured at a 1/3 octave bandwidth, (a) shows the wind noise characteristics of this embodiment, and (b) shows the wind noise characteristics. FIG. 4 shows the wind noise characteristics of the conventional condenser microphone shown in FIG. 4, and it was found that the wind noise of the embodiment was reduced by about 6 dB as a whole. It was also found from this measurement that it was particularly effective in a frequency band of 200 Hz or less.

[0016]

[Effect of the invention] As described above , according to the invention, the back pole
The notch in the plate allows vibration from the front acoustic terminals.
An air leakage path leading to the gap between the moving plate and the back plate
Within the unit case and the shortest distance,
Therefore, easy simply adding a slight improvement to the conventional configuration
It can simply be implemented.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of the present invention.

FIG. 2 is a plan view cut along line II-II of FIG.

FIG. 3 is an enlarged longitudinal sectional view showing a part of FIG. 1;

FIG. 4 is a longitudinal sectional view schematically showing an example of a conventional condenser microphone.

5A and 5B are graphs showing wind noise characteristics of this embodiment and a conventional condenser microphone. FIG. 5A shows this embodiment, and FIG. 5B shows a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Insulation seat 2 Back electrode plate 4 Ring 5 Vibration plate 6 Spacer 8 Through hole 11 Unit case 12 Opening 21 Notch 22 Wire mesh 23 Gap

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-61-219298 (JP, A) JP-A-61-234197 (JP, A) JP-A-4-207699 (JP, A) 77200 (JP, U) Japanese Utility Model Showa 57-57698 (JP, U) JP 6-100494 (JP, B2) Japanese Utility Model Showa 59-36078 (JP, Y2)

Claims (1)

(57) [Scope of request for utility model registration] (1)A unit case with a front acoustic terminal on the front
And the unit while being stretched and held on a ring.
Diaphragm placed on the front acoustic terminal side of the case and back electrode plate
And the back electrode plate is placed in the unit case.
Spacer so as to face the diaphragm with a constant gap
And an insulating seat disposed on the ring side via
In addition to having a rear acoustic terminal at the rear of the insulating seat,
A gap between the diaphragm and the back electrode plate and the front acoustic terminal
Condenser that has an air leakage path between
At Icrophone, The air leakage path is on the sound collecting surface side of the unit case.
From the gap of the wire mesh interposed between the inner peripheral surface and the ring
A first passage, an outer peripheral surface of the ring, and the unit case.
A second passage between the side surface inner peripheral surface of the base and the insulating seat;
A third passage formed between the ring and the third passage;
And a gap between the diaphragm and the back electrode plate.
And a notch provided in the back plate.
ing A condenser microphone characterized in that: