JP2003289598A - Microphone - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electret type capacitor microphone which is thin and has stable characteristics as a product. <P>SOLUTION: In the microphone 1, an inner peripheral face 51a of an upper face opening portion of a rubber boot 5 and a filter outer peripheral face 3a of the rubber boot 5 are arranged so as to face each other, and a filter 3 is arranged at the same position as that of the face 51a of the rubber boot 5. By arranging the filter 3, the microphone 1 can be prevented from increasing in thickness, and this configuration can contribute to reduction of thickness. Also, since a microphone opposing face 51b of the rubber boot 5 surface-contacts a peripheral upper face portion 12a of a sound collecting hole of the microphone 1, the filter 3 is prevented from being sandwiched between the capacitor microphone 10 and the rubber boot 5, and this configuration can contribute to the reduction and uniformization of thickness. In this way, in press-fitting the microphone 1 into an external device, positioning property is improved and a defective rate can be improved. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microphone, and more particularly to a structure for reducing the thickness and stabilizing the quality of a condenser microphone.

[0002]

2. Description of the Related Art Conventionally, an electret type condenser microphone has been known as one type of microphone.

This electret-type condenser microphone has a cylindrical case whose one surface has an upper surface having a sound collecting hole opening and the other surface is opened, and a diaphragm and a back surface which face each other via a spacer. A capacitor portion including a polar plate and a substrate on which an impedance conversion element (active element) for converting an impedance of the capacitor portion into an electric impedance is mounted are accommodated.
Further, as disclosed in, for example, Japanese Patent Laid-Open No. 11-98597, a filter member for preventing the entry of dust and the like is arranged on the sound collecting hole surface of the condenser microphone,
There is also a configuration in which a rubber case is covered on the outer periphery of the condenser microphone.

In such a structure, in most cases, a filter member is previously attached to the sound collecting hole surface of the condenser microphone and then housed in a rubber case.

[0005]

However, in recent years, as the thickness of mobile phones and the like has been reduced, the condenser microphone itself to be installed is required to be thinner. Therefore, in the case of the above-mentioned conventional condenser microphone, the thickness of the filter remains unchanged. There is a problem in that the thickness of the entire microphone is reduced, which is an obstacle to making the microphone thinner.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a microphone that is thin and has a stable product.

[0007]

The present invention is intended to achieve the above object by devising the arrangement of the filter member and the gasket portion of the microphone.

That is, the microphone according to the present invention includes a microphone section for collecting vibrations due to sound or the like from the sound collecting hole and converting the sound into an electric signal, and a filter capable of passing vibration such as sound for covering the sound collecting hole. And a gasket portion having elasticity to cover the outside of the microphone portion, and the gasket portion has an opening corresponding to the sound collection hole, and the opening is an inner peripheral surface of the opening. It is characterized in that the outer peripheral surfaces of the filter section are arranged so as to face each other. Further, the microphone according to the present invention is characterized in that it has a microphone facing surface on the opening side of the gasket portion, and the microphone facing surface is in surface contact with the outer peripheral upper surface of the sound collecting hole of the microphone portion. To do. The microphone according to the present invention is characterized in that a circumferential projection is provided on the upper surface of the opening of the gasket.

[0009]

As described above, the microphone according to the present invention is arranged such that the inner peripheral surface of the opening of the gasket portion and the outer peripheral surface of the filter portion face each other, and the filter portion has the opening of the gasket portion. Since the filter is arranged at the same position as the part, the thickness of the microphone itself is not increased by disposing the filter. Therefore, according to the present invention, it is possible to reduce the thickness of the microphone.

Further, since the surface of the gasket portion facing the microphone is in surface contact with the upper surface of the outer circumference of the sound collecting hole of the microphone portion, the filter portion is not sandwiched between the microphone portion and the gasket portion. Can contribute to the uniformity of the height. In addition, clear sound can be collected because the sound cannot circulate from the back of the microphone part. As a result, when the microphone is press-fitted into the external device, the positioning performance is improved, the defect rate is reduced, and the sound quality is also improved.

Further, since the circumferential projection is provided on the upper surface of the opening of the gasket, when the microphone is attached to an external device such as a mobile phone,
By crushing the protrusions, it is possible to increase the degree of adhesion,
The sound pressure of the collected sound can be improved. In addition, it is possible to reduce noise collection in the external device and collect only desired sound. This can contribute to the improvement of sound quality and product quality.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a plan view showing a microphone according to an embodiment of the present invention in a state in which the microphone is arranged upward.
2 is a sectional view taken along line II-II of FIG. 1, and FIG. 3 is
4A and 4B are cross-sectional views showing a method of mounting a microphone according to an embodiment of the present invention on an external device, FIG. 3A being a cross-sectional view before being assembled to the external device, and FIG. It is sectional drawing after an assembly.

As shown in these figures, the microphone 1 according to the present embodiment includes a condenser microphone 10 which is a microphone section and a filter 3 which is a filter section.
And a rubber boot 5 which is a gasket part.

First, the condenser microphone 10 is a small electret type microphone having an outer diameter of about 6.0 mm, and an insulating bush 20 is arranged in a short cylindrical case 12 extending vertically. The diaphragm sub-assembly 14, the spacer 16, the back electrode plate 18 which is a back plate, and the disc spring 22 are accommodated in this order from above in the inside, and further sealed by the JFET board 24 (substrate).

The case 12 has an upper surface (one surface) having an inner diameter of 0.
It has a plurality of sound collecting holes 30 of about 3 mm and a sound collecting hole outer peripheral upper surface portion 12a surrounding the sound collecting hole 30, and is made of metal (for example, aluminum) whose lower surface (other surface) is open. Which is formed by press molding or the like. And this case 12
With the above components housed in the case 12, the open end 12b is caulked and fixed to the outer peripheral edge of the JFET board 24 over the entire circumference.

A filter 3 is attached to the upper end of the case 12 so as to protect the sound collecting hole 30.
This prevents dust and water droplets from entering the inside of the condenser microphone 10.

A vent groove for adjusting the atmospheric pressure inside and outside the condenser microphone 10 is formed at the upper end of the case 12. The width of this vent groove is 0.2 mm
The depth is set to about 0.02 mm.

The filter 3 is formed of a non-woven fabric or mesh having a diameter of about 4.5 mm, and is attached to the condenser microphone 10 with a double-sided tape or the like so as to cover the sound collection hole 30. The filter 3 is arranged within the inner diameter of the upper opening 51 of the rubber boot 5.

Vibration plate sub-assembly 14 (diaphragm)
Is composed of a thin disc-shaped vibrating membrane 26 and a ring-shaped support frame 28 that fixes and supports the vibrating membrane 26. The fixed support of the vibrating membrane 26 by the support frame 28 is
The upper surface of the vibrating film 26 is bonded and fixed to the lower surface of the supporting frame 28 with an adhesive or the like, whereby the supporting frame 28 and the vibrating film 26 are electrically connected.

The vibrating membrane 26 is made of P having a thickness of about 1.5 μm.
A metal vapor deposition film of, for example, nickel (Ni) is formed on the upper surface of an ET (Polyethylene Terephthalate) film, and its outer diameter is the inner diameter of the insulating bush 20 (3.8 mm).
The value is set to a value (about 3.7 mm) which is slightly smaller than

On the other hand, the support frame 28 is made of metal (for example, stainless steel) and has an outer diameter substantially the same as that of the vibrating membrane 26 and an inner diameter of about 2.7 mm. In addition, when the diaphragm sub-assembly 14 is housed in the case 12, the metal vapor deposition film of the vibration film 26 is not supported by the support frame 2.
Since the case 12 is pressed against the case 12 by a pressing force described later, the case 12 is electrically connected.

The spacer 16 is a diaphragm sub-assembly 14
A frame-shaped member having an outer diameter substantially the same as the outer shape, and a large opening 16a is formed by pressing or the like in the center of a circular resin film PET having a plate thickness of about 25 μm.

The back electrode plate 18 (back plate) includes a back electrode plate body 180, an electret 182 formed on the upper surface of the back electrode plate body 180, and a plurality of back electrode plate bodies 180 and electrets 182. It consists of an opening.

The back electrode plate body 180 is made of a metal plate (for example, a stainless steel plate) having a substantially cross-shaped outer shape and a plate thickness of about 0.15 mm.

On the other hand, the electret 182 has a thickness of 2
FEP (Fluorinated Ethylene Propyle) of about 5 μm
ne) It consists of film.

After that, the electret 182 is subjected to a polarization treatment and is set so as to have a predetermined surface potential (for example, about -300 V). The back electrode plate 18 is housed in an insulating bush 20.

In the case 12, the back electrode plate 18 and the vibrating membrane 26 have a thickness of 25 with the spacer 16 interposed therebetween.
The capacitors are opposed to each other with an interval of about μm, and thereby the capacitor section is configured.

The insulating bush 20 has an outer diameter substantially the same as the inner diameter of the case 12, and a circular air chamber for accommodating the capacitor portion at one end portion (a position eccentrically arranged inside the outer shape circle) inside thereof. Further, it has a shape having an air chamber for accommodating the JFET chip 34 and an air chamber for accommodating the noise filter at the other end, and is made of elastic synthetic resin (for example, ABS resin) or elastomer. The thickness of the insulating bush 20 is such that the diaphragm sub-assembly 14, the spacer 16, the back electrode plate 18, and the disc spring 22 can be contained therein.
It is set to (about 0.5 mm).

The disc spring 22, which is an elastic body, is made of metal such as SUS and has a diameter of the upper portion (contact portion with the back electrode plate 18) narrower than that of the lower portion.
Connection part (conductive pattern 36) on the board 24 and the back electrode plate 18
Is to electrically connect with. Further, by using the disc spring 22, it becomes possible to fix the diaphragm sub-assembly 14, the spacer 16, the back electrode plate 18, etc. to the case 12 while exerting a pressing force when assembled, and the disc spring 22 However, since it is possible to absorb the caulking pressure at the time of assembly, it is possible to absorb an excessive caulking pressure load on the diaphragm sub-assembly 14, the spacer 16, the back electrode plate 18, etc., and prevent damage during assembly. be able to.

At the bottom of the disc spring 22, there are two notches and two notches, which are notches for retracting the circuit.
They are formed alternately every 0 °. The notch is notched 0.2 mm in the circumferential direction and 0.15 mm in the height direction. The notch portion is notched with a margin of about 0.3 mm from the width of the conductive pattern 36 in the circumferential direction. This notch has a conductive pattern 36 described later.
Is arranged so as to straddle the pattern so as not to come into contact with the drain electrode D. Further, since the conductive pattern 36 is straddled by the cutout portion, cutting of the conductive pattern 36 is also avoided at the same time.

The JFET board 24 includes a circular board body 32 and a JFET (Junction Field-Effect Transistor).
or) chip 34 and a noise filter such as a chip capacitor for cutting carrier wave noise of communication equipment such as a mobile phone are mounted. Board body 32
Has an outer diameter substantially the same as the inner diameter of the case 12, and predetermined conductive patterns 36 are formed on both upper and lower surfaces thereof. The conductive pattern 36 on the lower surface of the board body 32 has a bullseye shape, and a circular pattern is formed in the center.
A ring-shaped pattern is formed around it, and is connected to the conductive pattern 36 on the upper surface of the board body 32 through a through hole (not shown). Further, a terminal 39 that conducts to an external device is attached to the conductive pattern 36 on the lower surface of the board body 32.

The JFET chip 34 is an impedance conversion element for converting the change in the electrostatic capacitance between the vibrating membrane 26 and the back electrode plate 18 (that is, the electrostatic capacitance of the capacitor portion) into an electrical impedance, and is a board main body 32. It is mounted on the conductive pattern 36 formed on the upper surface.

The conductive pattern 36 includes the JFET chip 3
4 are electrically connected to the drain electrode, the source electrode, and the gate electrode, respectively, and electrodes corresponding to the respective electrodes are formed. A noise filter is mounted between the drain electrode and the source electrode of the conductive pattern 36. ing. The drain electrode of the conductive pattern 36 extends to the center of the board body 32, and the conductive pattern 3 on the lower surface of the board body 32 (the back surface of the mounting surface of the JFET chip 34) is formed by a through hole.
6 is electrically connected to the drain electrode.

The rubber boot 5 is an elastic member formed of an insulating resin such as rubber, and is formed so as to house the condenser microphone 10. The rubber boot 5 includes an upper surface opening 51 corresponding to the sound collection hole 30 of the condenser microphone 10 and the condenser microphone 10.
A lower surface opening 52 for leading out the terminal 39 is formed. The inner diameter of the upper opening 51 is slightly larger than the diameter of the filter 3 to prevent the filter 3 from being sandwiched between the condenser microphone 10 and 5.0 mm. The outer peripheral surfaces 3a face each other. Further, the inside of the upper surface of the rubber boot 5 is a microphone facing surface 51b which faces the upper surface of the condenser microphone 10 and particularly makes surface contact with the sound collecting hole outer peripheral upper surface portion 12a.

On the upper surface of this rubber boot 5, an annular projection 5 is formed.
4 is formed, and an annular projection 55 is formed on the lower surface. The annular projection 54 and the annular projection 55
Each of them has a mountain-shaped triangular shape in cross section, and is formed in an annular shape on the outer circumference of the opening of the upper surface or the lower surface of the rubber boot 5. The ring-shaped protrusion 54 and the ring-shaped protrusion 55 are configured to be crushed by a sandwiching pressure with the external device when attached to the external device, and enhance the degree of adhesion of the microphone 1 to the external device.

Next, a method of assembling the microphone 1 according to this embodiment to an external device will be described.

In assembling the microphone 1 to an external device such as a mobile phone, first, the microphone 1 is arranged between the external housing 61 and the external board 63. At this time, the terminals 39 are arranged on the external substrate 63, and the sound collection holes 30 are arranged on the sound hole side of the outer housing 61. Then, the microphone 1 is sandwiched between the outer housing 61 and the outer board 63, and the outer housing (not shown) on the lower surface of the outer board 63 and the outer housing 61 are fitted and fixed by a screw or the like, and the microphone 1 is placed between the outer housing 61 and the outer board 63. In close contact with.

As a result, the ring-shaped protrusion 54 is formed in the outer housing 6
The microphone 1 is crushed by the pressure contact force with the microphone 1, and the microphone 1 is attached to the external housing 6
It is possible to bring the sound into close contact with No. 1 without any gap, and to guide only the sound introduced from the sound hole of the outer housing 61 to the sound collecting hole 30. As a result, it is possible to prevent the microphone 1 from picking up, for example, a ring tone, a call sound, or other mechanical noise in the external device. Further, the annular protrusion 55 is also crushed by the pressure contact force with the external substrate 63, so that the microphone 1 can be brought into close contact with the external substrate 63 without a gap, and it is possible to prevent unwanted sound from entering from the back surface of the microphone 1.
Further, the space formed between the microphone 1 and the external substrate 63 can be used as a back pressure space.

As described in detail above, the microphone 1 according to this embodiment has the inner peripheral surface 51 of the upper surface opening of the rubber boot 5.
a and the outer peripheral surface 3a of the filter are arranged so as to face each other, and the filter 3 is arranged at the same position as the inner peripheral surface 51a of the upper surface opening of the rubber boot 5. Therefore, by disposing the filter 3, Since the thickness does not increase, it can contribute to thinning.

Also, the microphone-facing surface 51b of the rubber boot 5
Is the upper surface 1 of the outer circumference of the sound collection hole of the condenser microphone 10.
Since the filter 3 is not in contact with the condenser microphone 10 and the rubber boot 5 due to the surface contact with the 2a, it is possible to contribute to thinning and uniform thickness.
Thereby, when the microphone 1 is press-fitted into the external device, the positioning property is improved and the defective rate is also reduced.

Further, since the annular protrusion 54 is provided on the outer periphery of the upper surface opening 51 of the rubber boot 5, the annular protrusion 54 is crushed when the microphone 1 is attached to an external device such as a mobile phone. As a result, the microphone 1 can be brought into close contact with the outer housing 61 without any gap,
Only the sound introduced from the sound hole of the external housing 61 is collected by the sound collecting hole 30.
It becomes possible to lead to. As a result, it is possible to reduce, for example, a ringing tone, a call tone, or other mechanical noise in the external device that is picked up by the microphone 1, and it is possible to improve the sound collection sound pressure.

[Brief description of drawings]

FIG. 1 is a plan view showing a state in which a condenser microphone according to an embodiment of the present invention is arranged upward.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a cross-sectional view before assembling to an external device (a) and a cross-sectional view after assembling to an external device (b).

[Explanation of symbols]

1 microphone 3 filters 3a Filter outer peripheral surface 5 rubber boots 10 condenser microphone 12 cases 12a Sound collecting hole outer peripheral upper surface part 12b open end 14 Vibration plate sub-assy 16 spacers 16a opening 18 back plate 180 Back plate body 182 electret 20 insulating bush 22 Disc spring 24 JFET board (substrate) 26 Vibration film 28 Support frame 30 sound collection holes 32 board body 34 JFET chip 36 Conductive pattern 39 terminals 51 Top opening 51a Upper surface opening inner peripheral surface 51b Microphone facing surface 52 Lower surface opening 54,55 annular projection 61 External housing 63 External board

Claims (3)

[Claims] 1. A microphone section that collects vibration due to sound or the like from a sound collection hole and converts it into an electric signal, a filter section through which vibration such as sound for covering the sound collection hole can pass, and a microphone section of the microphone section. An elastic gasket portion covering the outside is provided, and the gasket portion has an opening corresponding to the sound collection hole, and the opening has an opening inner peripheral surface and an outer peripheral surface of the filter portion. A microphone characterized by being arranged so as to face each other. 2. A microphone facing surface is provided on the opening side of the gasket portion, and the microphone facing surface is in surface contact with an outer peripheral upper surface of the sound collecting hole of the microphone portion. Microphone as described. 3. The microphone according to claim 1, wherein a circumferential projection is provided on the upper surface of the opening of the gasket section.