JPH04265098A - Microphone - Google Patents

Abstract

PURPOSE:To obtain a small-sized microphone which sufficiently reduces the external oscillation noise. CONSTITUTION:A main audio microphone part A through which the external air oscillation is transmitted to a diaphragm 2 in a case 1 and an oscillating detecting microphone part B through which the external air oscillation is not transmitted to the diaphragm 2 in the case 1 are provided, and a signal corresponding to the output difference between both microphone parts A and B is outputted.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microphone for reducing external vibration noise.

0002

2. Description of the Related Art A microphone has a diaphragm inside a case, and when the diaphragm vibrates due to air vibration, it outputs an electrical signal in response to the vibration. However, if the case itself vibrates due to some kind of external vibration, this vibration also causes the diaphragm to vibrate, resulting in so-called external vibration noise.

[0003] In order to reduce this external vibration noise, it has been proposed in the past that a vibration absorbing mechanism is provided to prevent vibrations from being transmitted to the case of the diaphragm.

0004

However, in the conventional structure described above, a large suspension must be used in order to obtain a sufficient vibration damping effect. Therefore, it has the disadvantage that it cannot be used in handheld microphones, video cameras, tape recorders, and other built-in microphones that require miniaturization.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a compact microphone capable of sufficiently reducing external vibration noise.

[0006]

[Means for Solving the Problems] To achieve the above object, the microphone of the present invention has a main audio microphone part in which external air vibrations are transmitted to a diaphragm in the case, and a main audio microphone part in which external air vibrations are transmitted to a diaphragm in the case. and a vibration detection microphone section that is not transmitted to the plate, and has differential means that outputs a signal according to the difference between the output of the main audio microphone section and the output of the vibration detection microphone section.

[0007]

[Function] The main audio microphone section outputs a combination of sound caused by air vibration and external vibration noise caused by case vibration, and the vibration detection microphone section outputs external vibration noise caused by case vibration, so external vibration noise is detected from the differential means. A canceled audio signal is output.

[0008]

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a schematic configuration diagram showing a first embodiment of the present invention. In FIG. 1, the microphone has a main audio microphone section A and a vibration detection microphone section B, and both microphone sections A and B are arranged side by side in the same direction. The main audio microphone section A has a diaphragm 2 stretched inside a case 1, and this diaphragm 2
The inside of the case 1 is divided into a rear chamber 3 and a front chamber 4.

The rear chamber 3 is a sealed space, and the front chamber 4 is communicated with the outside air through a sound intake section 5 in which a large number of small holes 5a are formed. When air vibrations are transmitted to the front chamber 4 via the sound intake section 5, the diaphragm 2 vibrates due to the air vibrations. The diaphragm 2 vibrates not only due to air vibration but also due to the vibration of the case 1 itself, and converts this vibration into an electric signal and outputs it.

Similar to the main audio microphone section A, the vibration detection microphone section B has a diaphragm 2 stretched inside the case 1, and the inside of the case 1 is divided into a rear chamber 3 and a front chamber 4 by the diaphragm 2. ing. However, unlike the main audio microphone section A, not only the rear chamber 3 but also the front chamber 4 are made into a sealed space by a closing plate 6. Therefore, the structure is such that external air vibrations are not transmitted to the diaphragm 2, and the diaphragm 2 vibrates only due to the vibration of the case 1. This vibration of the diaphragm 2 is converted into an electrical signal and output.

The output of the main audio microphone section A and the output of the vibration detection microphone section B are input to a differential amplifier 7, which is a differential means, and the differential amplifier 7 outputs a signal corresponding to the difference between the two input signals. Amplify and output.

In the above configuration, the diaphragm 2 of the main audio microphone section A vibrates due to the air vibrations transmitted from the outside to the front chamber 4 and the vibrations transmitted from the case 1, so the main audio microphone section A vibrates between the voice and external vibration noise. Outputs the composite signal of In addition, since the diaphragm 2 of the vibration detection microphone section B vibrates only due to the vibration transmitted from the case 1, the vibration detection microphone section B
outputs a signal of external vibration noise.

Since the external vibration noise of the main audio microphone section A and the external vibration noise of the vibration detection microphone section B are almost the same, the differential amplifier 7 outputs a signal of only audio in which the external vibration noise is almost canceled. Ru. Main audio microphone section A
The more the external vibration noise of the main audio microphone section A and the vibration detection microphone section B are the same, the more the external vibration noise can be reduced. It is preferable that both diaphragms 2 are arranged in the same direction.

FIG. 2 is a schematic diagram showing a second embodiment of the present invention. In FIG. 1, the microphone has a main audio microphone section A and a vibration detection microphone section B, and both microphone sections A and B are arranged in a row on the same line. The main audio microphone section A is located at the front, and the vibration detection microphone section B is located at a constant interval at the rear. Also, since both microphone sections A and B have the same configuration as the main audio microphone section A of the first embodiment, the same reference numerals as those of the first embodiment are given in FIG. 2, and the explanation thereof will be omitted.

The sealing member 8 has a cylindrical shape, is tightly attached to the outer periphery of both the microphone parts A and B, and is attached to the vibration detection microphone part B.
A closed chamber 9 is constructed in front of the. The output of the main audio microphone section A and the output of the vibration detection microphone section B are led to the differential amplifier 7 as in the first embodiment.

In the above configuration, the main audio microphone section A picks up air vibrations and the vibrations of the case 1, but the vibration detection microphone section B picks up the air vibrations from the case 1 because external air vibrations are not transmitted into the sealed chamber 9. Picks up only the vibrations. Therefore, the differential amplifier 7 outputs an audio signal in which external vibration noise is substantially canceled, as in the first embodiment.

Furthermore, in this second embodiment, both microphone sections A
, B have the same configuration, and commercially available ones can be used, so there is a cost advantage.

FIG. 3 shows an example in which the present invention is applied to a hand microphone 10. In FIG. 3, a main audio microphone section A and a vibration detection microphone section B are arranged in a vertical line at the tip of the hand microphone main body 11. hand microphone 10
In this case, touch noise caused by hands is likely to occur, but this touch noise is reduced as external vibration noise.

FIG. 4 shows an example in which the present invention is applied to the built-in microphone 13 of the video camera 12. In FIG. 4, both microphone parts A and B are arranged in a vertical line on the upper part of the camera body 14. In the video camera 12, mechanical noise is generated from the lens drive system and the cassette tape drive system, but these mechanical noises are reduced as external vibration noise.

[0020]

As described above, according to the present invention, there is a main audio microphone section in which external air vibrations are transmitted to the diaphragm in the case, and a vibration detection unit in which external air vibrations are not transmitted to the diaphragm in the case. Since the microphone output signal is a signal corresponding to the output difference between the two microphone sections, the external vibration noise detected by both microphone sections is canceled and only the audio signal is output. Therefore, it is possible to provide a microphone that is small and can sufficiently reduce external vibration noise.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing a first embodiment of the present invention.

FIG. 2 is a schematic configuration diagram showing a second embodiment of the present invention.

FIG. 3 is a perspective view showing the case where the present invention is applied to a hand microphone.

FIG. 4 is a schematic diagram showing a case where the present invention is applied to a built-in microphone of a video camera.

[Explanation of symbols]

A... Main audio microphone section, B... Vibration detection microphone section, 1... Case, 2... Diaphragm, 7... Differential amplifier (differential means).

Claims (1)

[Claims] 1. The main audio microphone includes a main audio microphone section in which external air vibrations are transmitted to a diaphragm in the case, and a vibration detection microphone section in which external air vibrations are not transmitted to the diaphragm in the case. What is claimed is: 1. A microphone comprising differential means for outputting a signal according to a difference between an output of the vibration detection microphone section and an output of the vibration detection microphone section.