JP2006333076A - Waterproof microphone - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a structure of a waterproof microphone acquiring good acoustic characteristics while securing superior waterproofness. <P>SOLUTION: The microphone 10 is made to be press-fitted and jointed into a sleeve 33 formed around a sound collecting hole 31 of a case panel 30 in a state of the microphone being held by a shield member 20 made of rubber. The thin film 24 of the rubber is to be constituted by forming the opposing portion of the forming area of the sound hole 12 of the microphone 10 in the shield member 20 as a recess 23. A space is acquired at back and forth of the thin film 24 by forming an area opposing to the thin film 24 in the case panel 30 as a recess 32. A superior waterproof function is acquired in a state of the microphone being held by the shield member 20 press fitted therein, and the thin film 24 can effectively transmit audio sound (aerial vibration) inputted from the sound collecting hole 31 to the recessed portion 23. A microphone element 15 of the microphone 10 is designed to output the aerial vibration to be acquired through the sound hole 12 as an audio signal. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a waterproof microphone, and more particularly, to an improvement for obtaining good acoustic characteristics while ensuring excellent waterproof properties.

  Mobile phones and transceivers are sometimes used in rainy weather, and accidents such as accidental dropping into water may occur, so that the microphone portion is often made waterproof.

  Conventionally, as a structure of a waterproof microphone, as shown in Patent Documents 1 and 2 below, a waterproof membrane and a microphone are attached in close contact with a sound collecting hole formed in a casing of a device. In the structure, the sound (air vibration) input from the sound collection hole is guided to the inside of the microphone through the waterproof membrane attached to the microphone's sound port, and converted into an acoustic output signal. Will be.

  In addition, recently, a waterproof breathable membrane with a characteristic that does not allow gas such as air and water vapor to pass through, such as a porous film of tetrafluoroethylene resin, and solid particles and liquids with a large contact angle do not pass under normal conditions. A mesh-type waterproof breathable membrane with a sapphire has been developed, and Patent Documents 3 and 4 below propose a waterproof microphone structure using such a membrane.

Japanese Utility Model Publication No. 1-126677 Utility Model Registration No. 3104044 JP 2000-78676 A JP 2004-235870 A

By the way, in the case of the structure in which the waterproof film and the microphone are attached in close contact with the sound collecting hole formed in the casing, the microphone unit is generally a unit casing having a large number of small holes (sound openings) formed on the front surface. If an internal microphone element is built in and each sound port is hermetically sealed with a waterproof film, even if the waterproof film is a thin rubber film or resin film, it will be acoustic when attached to a small hole. In addition, the reproduced sound of the audio signal obtained from the microphone element does not have a sufficient volume and the sound quality is considerably deteriorated.
On the other hand, when a waterproof breathable membrane is used, the air vibrations of the sound pass through the membrane as it is, so that even if it is attached to the sound port on the front of the microphone unit as described above, a certain level of acoustics is ensured. However, due to its nature, as the depth of water resistance increases, the air permeability decreases remarkably, and there is a tendency to cause an extreme decrease in sound volume and deterioration in sound quality.

In portable communication devices used outdoors, the waterproof function is an important item that affects the value of the product, and a waterproof structure that is as complete as possible is required, but the microphone part is only waterproof, unlike other parts. The acoustic characteristics must also be considered.
Therefore, the present invention has been created with the object of providing a waterproof microphone structure capable of obtaining good acoustic characteristics while ensuring complete waterproofness.

  The present invention relates to a waterproof microphone that is attached to a sound collection hole forming portion of a case panel, and is made of a rubber that includes a cylindrical microphone having a sound port formed on the front end surface side, a front wall portion, and a hollow cylindrical portion. And holding the microphone by covering the front end surface of the microphone with the front wall portion and the edge portions of the side peripheral surface and the rear end surface of the microphone with the hollow cylindrical portion, and in the front wall portion. A seal member in which a thin film of rubber is formed by forming a portion facing the sound port forming region on the microphone side as a concave portion, and a central portion of the thin film forming region includes the seal member that holds the microphone. A sleeve that is fitted in a state facing the sound collection hole is formed, and in a region corresponding to the thin film configuration region of the seal member in the formation portion of the sound collection hole Parts made with the formed casing panels, according to the sealing member in holding the microphone waterproof microphone, characterized in that is fixed by press-fitting the sleeve of the case panels.

According to the present invention, an airtight waterproof structure is configured by press-fitting and fixing the seal member to the sleeve on the case panel side, and formed on the case panel side before and after the rubber thin film. Spaces are respectively formed by the recesses and the recesses formed in the seal member itself.
Therefore, the thin film generates a membrane vibration by the air vibration of the sound that has entered the front space from the sound collection hole of the case panel and efficiently transmits it to the rear space, and the microphone receives the sound through the sound opening. To do.
In addition, it is desirable that the peripheral edge portion of the thin film constituent region in the front wall portion of the seal member is formed so as to continue to the thin film constituent region while gradually reducing the thickness. This is because the peripheral portion of the thin film constituent region is always subjected to stress due to membrane vibration, and therefore damage due to fatigue is likely to occur if the thickness is changed in a manner of forming a step.
In addition, if a small protrusion that is continuous in the circumferential direction is formed on the outer peripheral surface of the hollow cylindrical portion of the seal member, the small protrusion serves as a packing and a stable waterproof mechanism can be obtained.

The waterproof microphone of the present invention realizes a waterproof structure in which confidential waterproofness is ensured by a sealing member that is a rubber member, and sound volume is not lowered and sound quality is hardly deteriorated by transmission of acoustic vibrations by a thin film.
Further, it is only necessary to press-fit and fix the microphone held by the seal member to the sleeve formed on the case panel, and there is an advantage that the assembling work can be simplified.

Hereinafter, embodiments of a waterproof microphone according to the present invention will be described with reference to the drawings.
First, FIG. 1 is a sectional view showing the structure of a waterproof microphone, FIG. 2 is a sectional view of each element, 10 is a microphone, 20 is a seal member, and 30 is a case panel.
Here, the microphone 10 has a cylindrical outer shape, and a large number of holes (sound openings 12) are formed in the central region of the front end plate portion 11, and the front end plate portion 11 and the hollow cylindrical portion 13 are integrally formed. The cover portion and the back plate 14 constitute an internal space, and the microphone element 15 is provided on the surface of the back plate 14 on the internal space side, and the lead terminal 16 is provided on the opposite surface.

The seal member 20 is made of silicon rubber, and the front end wall portion 21 and the hollow cylinder portion 22 are integrally formed, and the microphone 10 is held in the internal space.
Accordingly, the internal space is sized to fit the microphone 10 in close contact, and a locking portion 25 slightly protruding inward is formed on the rear end side, and the microphone 10 is inserted. In this state, the rear end face is locked.
A concave portion 23 is formed in a portion of the front end wall portion 21 facing the formation area of the sound port 12 of the microphone 10, and a central portion corresponding to the bottom of the concave portion 23 is a thin film 24. The peripheral edge of 24 has an arc-shaped cross section whose thickness gradually increases toward the outside.
The outer diameter of the hollow cylindrical portion 22 is set slightly larger than the inner diameter of a sleeve 33 of the case panel 30 described later.

On the other hand, a sound collecting hole 31 is formed on the case panel 30 from the front surface side, and a concave portion 32 is formed around the sound collecting hole 31 on the back surface side, and an annular position centered on the sound collecting hole 31. A sleeve 33 is formed upright.
As described above, the inner diameter of the sleeve 33 is slightly smaller than the outer diameter of the seal member 20.

Based on the configuration of each element described above, when the microphone 10 is assembled, the microphone 10 is first inserted into and held by the seal member 20.
In that case, the inner diameter of the locking portion 25 of the seal member 20 is smaller than the outer diameter of the hollow cylinder portion 13 of the microphone 10. However, since the seal member 20 is made of silicon rubber, the inner peripheral opening of the locking portion 25 is opened. It can be easily inserted by a method of pushing the cover portion of the microphone 10 in such a manner that the portion is pushed open.
Next, the seal member 20 holding the microphone 10 is press-fitted into the sleeve 33 of the case panel 30.
As described above, the outer diameter of the hollow cylindrical portion 22 of the seal member 20 is slightly larger than the inner diameter of the sleeve 33. However, since the seal member 20 is made of rubber, the sleeve 33 is deformed while being properly deformed during press-fitting. The front end wall portion 21 is in close contact with and fixed to the case panel 30.

When the microphone 10 is mounted on the case panel 30 in this way, the structure shown in FIG. 1 is obtained, but the microphone 10 held by the seal member 20 is prevented from being detached by the locking portion 25, and Since the hollow cylindrical portion 22 of the seal member 20 and the sleeve 33 of the case panel 30 are in a pressure contact relationship, they are fixed by a large frictional force.
On the other hand, acoustically, when an external sound (air vibration) enters the recess 32 through the sound collection hole 31 of the case panel 30, the air vibration vibrates the thin film 24 of the shield member 20, and the thin film 24 transmits the sound. The air vibration is efficiently transmitted as the air vibration of the recess 23. Then, the air vibration in the concave portion 23 propagates to the internal space of the cover portion through the sound port 12 of the microphone 10 and is detected as an audio signal by the microphone element 15.

Therefore, since water that has entered from the outside of the case panel 30 is sealed by the close contact state between the sleeve 33 and the seal member 20, it does not go around to the microphone 10 side, and a completely waterproof structure is always configured. .
In addition, the highly efficient and accurate air vibration transmission function by the rubber thin film 24 enables sound reproduction with little reduction in sound volume and sound quality.
Note that the periphery of the thin film 24 in the seal member 20 is a portion that is easily fatigued by acoustic vibration or pressure change. However, since the portion is formed in an arc-shaped cross section that gradually increases in thickness, the thin film 24 is cleaved by fatigue. Can be prevented.

The seal member 20 is formed by a method such as compression molding or injection molding. For example, when the microphone 10 has a cylindrical shape with a diameter of 5.5 mm and a length of 2 mm, the portion of the thin film 24 has a diameter of 3. It can be formed as a circular region having a thickness of 1 mm and a thickness of 0.1 mm.
Then, when the same microphone is used and the rubber film of the same thickness is interposed between the sound collecting hole of the case panel and the microphone as in the prior art to form a close contact structure, the seal member 20 is applied. When compared with the structure of the present embodiment (the hardness of the silicon rubber is 30 degrees), the result of the structure of the present embodiment is about 15 dB higher in comparison of the reproduction output for the same sound source.

Next, FIG. 3 shows a modified example of the seal member. This seal member 20 ′ is formed in the outer peripheral surface of the hollow cylindrical portion 22 in the circumferential direction to form small projections 26a and 26b having a half-moon shaped cross section. There is a feature. However, in FIG. 3, the part which attached | subjected the code | symbol same as FIG. 2 (B) shows the same part.
And the structure at the time of attaching the microphone 10 to the case panel 30 using the sealing member 20 'is shown in FIG.
As is clear from comparison between FIG. 1 and FIG. 1, when the sealing member 20 ′ is press-fitted into the sleeve 33 of the case panel 30, the small protrusions 26 a and 26 b are pushed inward by the inner peripheral surface of the sleeve 33. In this manner, the hollow cylindrical portion 22 is deformed, and the small protrusions 26 a and 26 b are strongly pressed against the inner peripheral surface of the sleeve 33 by a repulsive force based on the deformation.
Accordingly, the annular small protrusions 26a and 26b are surely brought into contact with the inner peripheral surface of the sleeve 33 over the entire circumference and can function as a stable packing, so that the waterproof function can be further improved.

  The present invention can be applied to a microphone mounting structure in a portable communication device such as a cellular phone or a transceiver.

It is sectional drawing which shows the structure of the waterproof microphone which concerns on embodiment of this invention. (A), (B), (C) are sectional views of a case panel, a sealing member, and a microphone, which are components of a waterproof microphone, respectively. It is sectional drawing and the right view of the sealing member which concerns on a modification. It is sectional drawing which shows the structure of the waterproof microphone in the case of using the sealing member of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Microphone, 11 ... Front end plate part, 12 ... Sound port, 13 ... Hollow cylinder part, 14 ... Back plate, 15 ... Microphone element, 16 ... Lead terminal, 20, 20 '... Seal member, 21 ... Front end wall part, DESCRIPTION OF SYMBOLS 22 ... Hollow cylinder part, 23 ... Recessed part, 24 ... Thin film, 25 ... Locking part, 26a, 26b ... Small protrusion, 30 ... Case panel, 31 ... Sound collecting hole, 32 ... Recessed part, 33 ... Sleeve.

Claims (3)

In the waterproof microphone attached to the formation part of the sound collection hole of the case panel,
A cylindrical microphone in which a sound port is formed on the front end surface side;
A rubber member comprising a front wall portion and a hollow cylindrical portion, the front wall portion covering the front end surface of the microphone, and the hollow cylindrical portion covering the edge portions of the side peripheral surface and the rear end surface of the microphone, respectively. While holding the microphone, a seal member in which a thin film of rubber is configured by forming a concave portion of the front wall portion facing the microphone-side sound mouth forming region;
A sleeve is formed to fit the seal member holding the microphone in a state where the central portion of the thin film configuration region faces the sound collection hole, and the thin film configuration of the seal member in the formation portion of the sound collection hole It consists of a case panel with a recess formed in the area corresponding to the area,
A waterproof microphone, wherein the sealing member holding the microphone is press-fitted into a sleeve of the case panel and fixed.   2. The waterproof microphone according to claim 1, wherein a peripheral edge portion of the thin film constituent region in the front wall portion of the seal member is formed so as to continue to the thin film constituent region while gradually reducing the thickness. The waterproof microphone according to claim 1 or 2, wherein the seal member is formed by forming small protrusions continuous in the circumferential direction on the outer peripheral surface of the hollow cylindrical portion.

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