JPS5848600A - Electrostatic sound converter - Google Patents

Abstract

PURPOSE:To avoid the displacement at the static state of a diaphragm film, by arranging an equalizer to another surface of the diaphragm film opposed to a fixed electrode and applying a DC current to the equalizer. CONSTITUTION:An electrostatic sound converter consists of an equalizer 1 for the compensation of a high frequency characteristic, the 1st insulator 2 of ring shape, a diaphragm film 3, a fixed frame 4 supporting the film 3, the 2nd insulator 5 of ring shape and a fixed electrode 6. A power supply for DC bias is applied from terminals 10 and 11 and a displacement force due to staticelectricity can be generated between the film 3 and the equalizer 1. A power supply is applied from terminals 11 and 12 and the displacement force due to the staticelectricity is exerted between the film 3 and the fixed electrode 6. Thus, the film 3 can be supported with a stable state.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrostatic type acoustic transducer, and its object is to provide an electrostatic type acoustic transducer with good stability by eliminating displacement of a diaphragm in a static state due to a DC bias voltage. An object of the present invention is to provide an acoustic transducer.

Generally, in an electrostatic acoustic transducer, a vibrating membrane with an electrode membrane provided on one side of the film is tensioned and installed on a fixed frame, and a fixed electrode is provided at a predetermined interval on the electrode membrane side of the vibrating membrane. By applying a predetermined DC bias voltage between the electrode film of the vibrating membrane and the fixed electrode, the mechanical displacement of the vibrating membrane is electrostatically converted and extracted. However, in the conventional electrostatic acoustic transducer described above, it is necessary to apply a predetermined DC bias voltage between the electrode film of the diaphragm and the fixed electrode. A displacement force due to static electricity acts, causing the vibrating membrane to bend and become distorted in a static state. Therefore, in a static state, the effective gap between the vibrating membrane and the fixed electrode becomes smaller than the mechanical dimension, resulting in a problem of lowered sensitivity and worsened S/N ratio.

The present invention solves these conventional drawbacks,
An equalizer is placed on the other side of the vibrating membrane facing the fixed electrode, and a DC voltage is applied between the equalizer and the vibrating membrane to generate displacement due to static electricity acting between the vibrating membrane and the fixed electrode. A displacement force equal to the force is applied, and due to the vibration vibration, the effective gap between the diaphragm and the fixed electrode becomes equal to the mechanical dimension, which can reduce sensitivity and improve S/N. It has the advantage of being able to

EMBODIMENT OF THE INVENTION Hereinafter, the electrostatic acoustic transducer of this invention is demonstrated with the drawing of an Example.

FIG. 1 shows an embodiment of the electrostatic acoustic transducer of the present invention. In the figure, 1 is an equalizer for compensating for high frequency characteristics, and 2 is a ring-shaped one provided around the outer periphery of the equalizer 1. a first insulator 3, a diaphragm made of a polymer film having an electrode film 3a on one side; 4 a diaphragm attached to the outer peripheral edge of the diaphragm 3 to support the diaphragm 3 in tension; 6 is a ring-shaped fixed frame; 6 is a ring-shaped second insulator;
is a cup-shaped fixed electrode, and a resistance material 7 is provided on the t-plane thereof. The fixed electrode 6 has the second electrode on its outer periphery.
With the insulator 6 attached, a vibrating membrane 3 supported so as to give a predetermined tension to the fixed frame 4 is disposed on the upper surface thereof, and an equalizer 1 provided with the first insulator 2 is further disposed, After that, the fixed frame 4, the second insulator 6, and the nineteenth insulator 2 are bonded with an adhesive 8.9, thereby forming the fixed electrode 6 as shown in FIG.
The equalizer 1 and the vibrating membrane 3 are assembled so that the gap dimension ~ between the equalizer 1 and the vibrating membrane 3 is equal to the gap dimension d1 between the equalizer 1 and the vibrating membrane 3. Further, as shown in FIG. 3, the outer diameter of the vibrating membrane 3 is smaller than the outer diameter of the fixed frame 4, and the upper surface of the fixed frame 4 has a bonding surface for the adhesive 9. Therefore, the fixed frame 4 can be firmly joined and attached to the first insulator 2 and the equalizer 1.

The equalizer 1 is connected to a terminal 10.

The fixed frame 4 is connected to the terminal 11, and the fixed electrode 6 is connected to each terminal 1. The converter has a DC bias power source 13 connected to the terminal 11 and connected to the terminal 12 via a resistor i4 as shown in FIG.
The terminals 12 and 11 are connected to the microphone amplifier 16 via a DC FFI blocking capacitor 16.

The electrostatic acoustic transducer configured as described above is described in 51. above. - A power supply 13 for DC bias is applied from the terminal 10.11, and a displacement force due to static electricity acts between the vibrating membrane 3 and the equalizer 1, and a power supply for DC bias is applied from the terminal 11.12. 13 is applied, and a displacement force due to electrostatic force acts between the vibrating membrane 3 and the fixed electrode 6. At this time, the gap dimension d1 between the vibrating membrane 3 and the equalizer 1 is equal to the gap dimension ~ between the vibrating membrane 3 and the fixed electrode 6, and the voltages applied therebetween are also approximately equal. Therefore, the displacement force due to static electricity that acts between the respective gaps is equal, and the vibrating membrane 3 is not displaced due to static electricity in a static state, but stands still in a state where mechanical tension is applied. Therefore, the vibrating membrane 3 is supported in a stable state, and it is possible to reduce the sensitivity and improve the S/N ratio.

In the above embodiment, the fixed frame 4 of the vibrating membrane 3 is connected to the fixed electrode e.
However, when the fixing frame 4 is provided on the equalizer 1 side with the electrode film 3 of the vibrating membrane 3 facing the equalizer 1 side, the same procedure can be performed to obtain an equivalent 99. ,,□■yo78□4゜Ah. According to the present invention as described above, a vibrating membrane having an electrode membrane on one side is disposed facing a fixed electrode, and an equalizer is disposed on the other side of the vibrating membrane facing the fixed electrode. between the equalizer and the diaphragm, and the static electricity that acts between the diaphragm and the fixed electrode due to a DC bias voltage applied between the diaphragm and the fixed electrode. Since a DC voltage was applied so that a displacement force equal to the displacement force caused by can be supported to be equal to the given dimensions. Therefore, the child diaphragm has the advantage that there is no distortion in a static state, and it can greatly improve sensitivity reduction and S/N ratio.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of the electrostatic acoustic transducer of the present invention, FIGS. 2 and 3 are enlarged sectional views of the vocal part of the transducer, and FIG. 4 is an illustration of the transducer. FIG. 7 is a block diagram showing a usage example. 1...I1 riser 2.6...Insulator 300.11. Vibration membrane, 3 a,'m,, Electrode membrane, 4, Fixed frame, 6...Fixed electrode, 8, 9...Adhesive, 13... ...Electrode for direct current earrings. Name of agent: Patent attorney Toshio Nakao and one other person JP-A-58-48GOO (3)

Claims (1)

[Claims] A vibrating membrane having an electrode membrane on one side is disposed to face the fixed electrode, and an equalizer is disposed to face the other side of the vibrating membrane facing the fixed electrode, between the equalizer and the vibrating membrane. A DC voltage is applied so that a displacement force equal to a displacement force due to static electricity acting between the vibration membrane and the fixed electrode is applied by a DC bias voltage applied between the vibration membrane and the fixed electrode. An electrostatic acoustic transducer.