WO2009005211A1

WO2009005211A1 - Diaphragm with air groove and condenser microphone using the same

Info

Publication number: WO2009005211A1
Application number: PCT/KR2008/001860
Authority: WO
Inventors: Jong-Sub Lee; Kyoung-Ku Han
Original assignee: Bse Co., Ltd.
Priority date: 2007-07-03
Filing date: 2008-04-03
Publication date: 2009-01-08
Also published as: KR20090000180U; CN201197187Y

Abstract

Provided is a condenser microphone with a diaphragm plate having an air groove. The condenser microphone includes a container-shaped case having an open side and a mesh sound hole disposed in a middle portion of a bottom, a diaphragm plate including a polar ring and a diaphragm, the polar ring including an air groove for providing an air flow for the mesh sound hole in the middle portion when being in close contact with the case, the diaphragm being vibrated by a sound pressure introduced through the mesh sound hole, a backplate including a sound hole, a spacer for forming a space between the diaphragm plate and the backplate, an insulating base for electrically insulating the backplate from the case, a conductive base electrically insulated from the case through the insulating base, and a printed circuit board (PCB) on which a connection terminal and a circuit part are mounted, the PCB electrically connected to the backplate through the conductive base and connected to the diaphragm plate through the case.

Description

DIAPHRAGM WITH AIR GROOVE AND CONDENSER MICROPHONE USING THE SAME

Technical Field

[1] The present invention relates to a condenser microphone, and more particularly, to a condenser microphone with a diaphragm plate having an air groove. Background Art

[2] Condenser microphones are widely used in mobile communication terminals and audio equipment. A typical condenser microphone includes a voltage bias element, a diaphragm/backplate pair configured to form a capacitor (C) varying with a sound pressure, and a junction field effect transistor (JFET) configured to buffer an output signal. Such a typical condenser microphone is fabricated by assembling a diaphragm plate, a spacer ring, an insulating ring, a backplate, a conductive ring, and a printed circuit board (PCB) within a case, and curling an edge portion of the case.

[3] FIG. 1 is a cross-sectional view illustrating a condenser microphone assembly according to a related art. The related art microphone assembly has a structure that a diaphragm plate 12 including a diaphragm and a polar ring, a spacer 13, a backplate 14, an insulating base 15, a conductive base 16 are inserted into a case 11, and finally a printed circuit board (PCB) 17 is mounted to the case 11 and an edge portion of the case 11 is curled.

[4] A sound hole 1 Ia is disposed in a middle portion of a bottom of the case 11 to introduce an external sound. An air groove 1 Ib, connecting the middle portion of the bottom to a surrounding portion thereof, is radially disposed to provide an air passage when the case 11 comes in close contact with the diaphragm plate 12.

[5] Meanwhile, a condenser microphone has been proposed, which includes a mesh provided to a sound hole in a case, to prevent a foreign material from being introduced through the sound hole for introducing external sound.

[6] However, since a case of a condenser microphone including such a mesh sound hole is thinner than a typical case, it is actually difficult to form an air hole in the same way as a related art. Disclosure of Invention

Technical Problem

[7] The present invention has been made in an effort to solve the above-described problems of the related art. An object of the present invention is to provide a condenser microphone with a diaphragm plate having an air groove for allowing an air flow. Technical Solution [8] To achieve the objects of the present invention, there is provided a diaphragm plate including: a diaphragm vibrated by a sound pressure introduced through a sound hole; a polar ring to which the diaphragm is attached including an air hole and forming a space allowing the diaphragm to vibrate, the air hole allowing an air flow between an inner side and an outer side of the ring.

[9] There is also provided a condenser microphone including: a container-shaped case having an open side and a mesh sound hole disposed in a middle portion of a bottom; a diaphragm plate including a polar ring and a diaphragm, the polar ring including an air groove for providing an air flow for the mesh sound hole in the middle portion when being in close contact with the case, the diaphragm being vibrated by a sound pressure introduced through the mesh sound hole; a backplate including a sound hole; a spacer for forming a space between the diaphragm plate and the backplate; an insulating base for electrically insulating the backplate from the case; a conductive base electrically insulated from the case through the insulating base; and a printed circuit board (PCB) on which a connection terminal and a circuit part are mounted, the PCB electrically connected to the backplate through the conductive base and connected to the diaphragm plate through the case.

Advantageous Effects

[10] According to the present invention, when a case having a mesh sound hole is employed, an air passage is provided through an air hole disposed in a diaphragm plate, so that the diaphragm in equilibrium provides a favorable sound quality.

Brief Description of the Drawings [11] FIG. 1 is a cross-sectional view illustrating a condenser microphone assembly according to a related art. [12] FIG. 2 is a view illustrating a diaphragm plate including an air groove according to an embodiment of the present invention. [13] FIG. 3 is a cross-sectional view illustrating a condenser microphone assembly according to an embodiment of the present invention. [14] * DESCRIPTION OF THE SYMBOLS IN MAIN PORTIONS OF THE

DRAWINGS*

[15] 110: Case 110a: Mesh Sound Hole

[16] 120: Diaphragm Plate 122: Diaphragm

[17] 124: Polar Ring 124a: Air Groove

[18] 130: Spacer 140: Backplate

[19] 140a: Sound Hole 150: Insulating Base

[20] 160: Conductive Base 170: PCB

Best Mode for Carrying Out the Invention [21] Hereinafter, embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[22] FIG. 2 is a view illustrating a diaphragm plate including an air groove according to an embodiment of the present invention. FIG. 3 is a cross-sectional view illustrating a condenser microphone assembly according to an embodiment of the present invention.

[23] Referring to FIG. 2, a diaphragm plate 120 includes a diaphragm 122 and a polar ring

124. The diaphragm 122 is vibrated by an external sound pressure. The polar ring 124 to which the diaphragm 122 is attached, forms a space between a case 110 and the diaphragm 122 to allow the diaphragm 122 to vibrate. The polar ring 124 includes an air groove 124a on both sides thereof to allows an air flow with a sound hole 110a disposed in a middle portion of a bottom of the case 110.

[24] Referring to FIG. 3, a condenser microphone assembly with the diaphragm plate 120 including the air groove 124a, includes a container-shaped case 110, the diaphragm plate 120, a spacer 130, a backplate 140, an insulating base 150, a PCB 170, and a conductive base 160. The case 110 provides a mesh to the sound hole 110a. The diaphragm plate 120 provides an air passage for the sound hole 110a in the middle portion and allows the diaphragm 122 to be vibrated by an external pressure when the polar ring 124 including the air groove 124a comes in close contact with the case 110. The spacer 130 forms a space between the diaphragm plate 120 and the backplate 140. The backplate 140 includes a sound hole 140a. The insulating base 150 electrically insulates the backplate 140 from the case 110. The conductive base 160 is electrically insulated from the case 110 by the insulating base 150, but electrically connects the backplate 140 to the PCB 170. Connection terminals and circuit parts are mounted on the PCB 170.

[25] The case 110 is a metal cylindrical or tetragonal container thinner than a related art, to provide the mesh to the sound hole 110a. A side of the case 110 is opened, and the mesh sound hole 110a for introducing an external sound is disposed in the middle portion of the bottom.

[26] As described above, the diaphragm plate 120 includes the diaphragm 122 and the polar ring 124. The diaphragm 122 is vibrated by a sound pressure introduced through the mesh sound hole 110a. The polar ring 124 to which the diaphragm 122 is attached, includes the air groove 124a. The air groove 124a allows an air flow between the middle portion of the bottom of the case 110 and a surrounding portion. The polar ring 124 forms the space between the case 110 and the diaphragm 122 to allow the diaphragm 122 to vibrate.

[27] Since the spacer 130, the backplate 140, the insulating base 150, the conductive base

160, and the PCB 170 have the same configuration as those of a typical condenser microphone, further description is omitted. [28] The operation of the condenser microphone assembly according to the present invention will now be described.

[29] In the completed condenser microphone assembly, the diaphragm 122 functioning as a movable electrode is connected to an electric circuit of the PCB 170 through a conductive path formed by the polar ring 124 and the case 110, and the backplate 140 functioning as a fixed electrode is connected to the electric circuit of the PCB 170 through the conductive base 160.

[30] When an external sound is introduced through the mesh sound hole 110a of the case

110, the diaphragm 122 vibrates to cause variations in a distance between the diaphragm 122 functioning as a movable electrode and the backplate 140 functioning as a fixed electrode. Accordingly, a capacitance varies between the fixed electrode and the movable electrode. The variations in the capacitance are signal-processed by a semiconductor device mounted on the PCB 170 and transmitted to the outside through the connection terminals.

[31] In the condenser microphone assembly according to the present invention, a back chamber as a space behind the diaphragm 122 is connected to the air passage reaching the mesh sound hole 110a through the conductive base 160, the insulating base 150, and the air groove 124a in the polar ring 124. Accordingly, air pressure in both spaces separated by the diaphragm 122 is in equilibrium to provide a favorable sound quality.

[32] Although embodiments have been described with reference to a number of illustrative embodiments thereof, it should be understood that numerous other modifications, variations, replacements, and additions can be devised by those skilled in the art, which will fall within the sprit and scope of the following claims.

Claims

[ 1 ] A diaphragm plate comprising: a diaphragm vibrated by a sound pressure introduced through a sound hole; a polar ring to which the diaphragm is attached including an air groove and forming a space allowing the diaphragm to vibrate, the air hole allowing an air flow between an inner side and an outer side of the ring.

[2] A condenser microphone comprising: a container- shaped case having an open side and a mesh sound hole disposed in a middle portion of a bottom; a diaphragm plate including a polar ring and a diaphragm, the polar ring including an air groove for providing an air flow for the mesh sound hole in the middle portion when being in close contact with the case, the diaphragm being vibrated by a sound pressure introduced through the mesh sound hole; a backplate including a sound hole; a spacer for forming a space between the diaphragm plate and the backplate; an insulating base for electrically insulating the backplate from the case; a conductive base electrically insulated from the case through the insulating base; and a printed circuit board (PCB) on which a connection terminal and a circuit part are mounted, the PCB electrically connected to the backplate through the conductive base and connected to the diaphragm plate through the case.