JPS58143697A - Electromagnetic microphone - Google Patents

Abstract

PURPOSE:To give the resistance to a high input to a microphone and make the microphone light-weight, by attaching a magnet to a diaphragm so that the direction of the magnetic pole is at right angles to the diaphragm and arranging a ring-shaped coil, whose center coincides with the center of the magnet, near this magnet. CONSTITUTION:A magnet 1 is attached to a diaphragm 2 so that the direction of the magnetic pole is at right angles to the diaphragm 2, and a ring-shaped coil 3 is arranged in a proper position near this magnet 1 so that the center of this coil 3 coincides with the center of the magnet. When the diaphragm 2 is oscillated by an external acoustic pressure, the permanent magnet 1 is displaced in the direction (of an arrow) orthogonal to the diaphragm 2, and the magnetic flux across the coil 3 is changed in accordance with this displacement, and a current due to an electromotive force is taken out from a coil output end 6.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electromagnetic microphone, and an object of the present invention is to provide a 1-microphone with excellent resistance to high input and high temperatures, and high production efficiency.

In a conventional dynamic microphone, a permanent magnet is fixed to an iron core to form a magnetic circuit, and a coil attached to a diaphragm is disposed in an air gap near the permanent magnet. When the Eri diaphragm vibrates due to external sound pressure, the vibration is transmitted to the coil, the magnetic flux changes, and a current due to electromotive force can be extracted from the output end of the coil.However, in this conventional configuration, the coil is Since it is not possible to increase the number of turns, in order to increase the efficiency, it is necessary to minimize the distance between the air gaps in order to increase the total magnetic flux density of the air gaps.However, in this case, the coil moves in a direction perpendicular to the diaphragm. Therefore, when the air gap is small, there is a problem in that the coil and the iron core come into contact and prevent proper operation.

For this reason, there is a problem in that efficient microphones inevitably have a high defect rate. Furthermore, since the heat dissipation condition of the coil is not very good, there is also the problem that in the case of a high electromotive force, the coil becomes hot and can be damaged.

The present invention is proposed to solve these problems, and embodiments will be described below with reference to the drawings.

In the present invention, a magnet 1't- is attached to the diaphragm 2 so that the direction of the magnetic pole is at right angles, and a ring-shaped coil 3 is arranged at an appropriate position near the magnet 1 so that its core coincides with the magnet core. Full abstract.

To explain, when the diaphragm 2 vibrates due to external sound pressure, the permanent magnet 1 moves in a direction perpendicular to the diaphragm 2 (in the direction of the arrow).
, and the coil 3 is cut accordingly. When the magnetic flux changes, an electric current (N) can be extracted from the electromotive force at the coil output end.In the present invention with the above configuration, the coil 3ti is fixed, so it is possible to increase the number of sets, thereby increasing the efficiency of the microphone. However, it is also possible to process the coil 3 with a heat dissipation stopper.
No damage even under high input and high temperature conditions
Secondly, since there is no air gap unlike in dynamic microphones, it is possible to avoid a situation where the permanent magnet 1 comes into contact with the coil 3 even if the diaphragm 2 moves significantly.

In the case of a dynamic microphone, since air force cannot be obtained, the yield rate in production inevitably deteriorates, but in the present invention, there may be a distance of about 3 mm between the permanent magnet 1 and the coil 30, and the above-mentioned yield improvement can be achieved. It became possible to do so.

Note that even if the material of the diaphragm 2 in the present invention is not particularly different from that of the conventional one, the performance as a microphone is not affected.

FIGS. 2 to 4 show other embodiments, but FIG. 4 is similar to the case where the diaphragm diameter is 20 mm or less.

As described above, the invention according to the present invention has a configuration that can achieve the same performance, have a good production yield, and can be automated in production, has excellent resistance to high input power and high temperature, and is lightweight. This makes it possible to create an electromagnetic microphone with a configuration that allows the vibration system and coil to be separated.

[Brief explanation of drawings]

FIG. 1 shows the Vcg1. FIGS. 2 and 4 are vertical cross-sectional views of an embodiment of an electromagnetic microphone according to another embodiment. In the figure 1 = Permanent magnet 2; Vibration plate 3; Coil 4 = Gap 6: Iron core 6: Coil output end Pl: Frame A-i: Core position line Patent applicant Mitachi Sound Manufacturing Co., Ltd. Figure 2 ^

Claims (1)

[Claims] An electromagnetic microphone characterized in that a magnet is attached to a diaphragm so that its magnetic poles are oriented at right angles, and a ring-shaped coil is disposed at an appropriate position near the magnet so that its core coincides with the magnet core.