JP2003092792A - Condensor microphone - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent without losing sound quality and an outward appearance. SOLUTION: In the condensor microphone 10 with the microphone unit 14 where a prescribed polarization voltage is applied between a diaphragm and a fixed pole, a dust collection electrode 16 made of e.g. an electret member 161 to which a voltage higher than the polarization voltage is applied is placed in the vicinity of the microphone unit 14.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a condenser microphone, and more particularly to a dustproof technology for its microphone unit.

[0002]

2. Description of the Related Art A condenser microphone is provided with a microphone unit in which a diaphragm and a fixed pole are opposed to each other with a predetermined gap, and a microphone unit is usually provided between the diaphragm and the fixed pole.
A polarization voltage (DC bias) of about V is applied to form a capacitor, and a capacitance change due to vibration of the diaphragm is extracted as an audio signal via, for example, an impedance converter.

As described above, the polarization voltage is applied to the microphone unit, but the electrostatic attraction force generated by the polarization voltage easily causes dust and dirt to adhere to the microphone unit. In order to prevent this, conventionally, the microphone unit is covered with a dust collecting filter made of a porous material such as urethane foam or a material having high air permeability such as nylon mesh or nonwoven fabric.

[0004]

However, in a condenser microphone for sound collection used in a recording studio or the like, it is not preferable to cover the microphone unit with the dust collecting filter as described above in terms of sound quality and appearance. , The microphone unit is stored in the outer casing (wind screen) while being exposed.

Therefore, during long-term use, dust is gradually accumulated on the microphone unit due to the electrostatic attraction generated by the polarization voltage, and when humidity is added to this, the polarization voltage leaks and noise is generated. Generate. Even if the microphone unit is regularly cleaned, it is difficult to remove dust cleanly because the electret type condenser microphone is constantly applied with the polarization voltage.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a condenser microphone capable of preventing adhesion of dust to a microphone unit without impairing sound quality and appearance. To provide.

[0007]

To achieve the above object, the present invention relates to a condenser microphone having a microphone unit in which a predetermined polarization voltage is applied between a diaphragm and a fixed pole. Is characterized in that a dust collecting electrode set to a voltage higher than the above-mentioned polarization voltage is disposed in the vicinity of.

The dust collecting electrode is preferably an electret material that maintains a charged state almost semipermanently, but is a plate electrode, a linear electrode or a needle electrode to which a voltage is applied from a high voltage generating circuit. Good.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a front side sectional view of a condenser microphone according to an embodiment, and FIG. 2 is a side side sectional view thereof. The condenser microphone 10 according to this embodiment is a stand-type microphone that is used by being attached to a microphone stand, but the present invention is not limited to this type of microphone.

The condenser microphone 10 includes a microphone body 11 supported by a microphone stand (not shown),
The microphone main body 11 is covered with an outer casing (wind screen) 12.

A unit mount 13 is mounted on the upper part of the microphone body 11, and a microphone unit 14 is mounted on the unit mount 13. In addition, an electric circuit board 15 including an impedance converter made of, for example, an FET, a signal amplifier circuit, etc. is housed in the microphone body 11.

In this embodiment, the microphone unit 1
Reference numeral 4 is a double diaphragm type in which diaphragms are arranged on both sides of the fixed pole, but it may be a normal single diaphragm type. The polarization voltage may be obtained from an electret material, or a polarization power source may be mounted on the electric circuit board 15,
The polarization voltage may be obtained from the polarization power supply.

According to the present invention, the dust collecting electrode 16 is provided near the microphone unit 14. In this embodiment, the dust collecting electrode 16 is made of an electret material 161 and
Position of the microphone unit 1 within the unit mount 13
They are arranged in a ring along the upper edge closest to 4.

The electret material 161 is charged with a voltage higher than the polarization voltage of the microphone unit 14.
For example, the polarization voltage of the microphone unit 14 is 50 to 100.
2k for the electret material 161 assuming that it is about V
It is preferable that a high voltage of about V is charged.

According to this, the dust floating in the outer casing 12 is attracted to the electret material 161 by the electrostatic attraction force higher than the polarization voltage of the microphone unit 14, and is captured by the electret material 161. .

When the electret material 161 is arranged along the upper edge of the unit mount 13, as shown in FIGS. 1 and 2, the upper edge shoulder portion of the unit mount 13 forms a mountain hem when viewed from the microphone unit 14 side. It is preferable to form such a tapered surface in order to enhance the dust collection effect.

Unlike the above embodiment, a plate electrode, a linear electrode or a needle electrode may be used as the dust collecting electrode 16. According to such an electrode structure, the electret material 1
The dust collecting electrode can be brought closer to the microphone unit 14 than 61.

On the other hand, in this case, a high voltage generating circuit for applying a high voltage to the dust collecting electrode 16 is required, but the electric circuit board 15 of the microphone main body 11 is provided with the microphone unit 14.
In the case where a polarization power source for electric power is installed, a predetermined high voltage for the dust collecting electrode can be obtained from the polarization power source by, for example, a voltage doubler rectifying circuit.

[0019]

As described above, according to the present invention,
In a condenser microphone having a microphone unit that applies a predetermined polarization voltage between a diaphragm and a fixed pole, a dust collection electrode set to a voltage higher than the polarization voltage is arranged near the microphone unit. By doing so, it is possible to prevent dust from adhering to the microphone unit without impairing the sound quality or appearance.

[Brief description of drawings]

FIG. 1 is a front side sectional view of a condenser microphone according to an embodiment of the present invention.

FIG. 2 is a side sectional view of the condenser microphone.

[Explanation of symbols]

10 condenser microphone 11 Microphone body 12 outer casing 13 unit mount 14 microphone unit 15 Electric circuit board 16 Dust collecting electrode 161 electret material

Claims (2)

[Claims] 1. A condenser microphone having a microphone unit configured to apply a predetermined polarization voltage between a diaphragm and a fixed pole, wherein a voltage higher than the polarization voltage is set in the vicinity of the microphone unit. A condenser microphone characterized in that a dust collecting electrode is arranged. 2. The condenser microphone according to claim 1, wherein the dust collecting electrode is made of an electret material.