JP2000333290A - Electroacoustic transducer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electroacoustic transducer that keeps a mechanical stability even when receiving a large pressure with excellent water-proof. SOLUTION: The electroacoustic transducer is provided with a diaphragm 6 having a central part 8 and a peripheral part 7 and with a coil 9 that is directly or indirectly fixed to a transit region between the central part 8 and the peripheral part 7, and the coil 9 is projected through a torus gap 11 formed between an upper yoke 5 and a lower yoke 4. Since a support member 10 is placed between the central part 8 and the upper yoke 5 at a distance from the diaphragm, even when a large pressure is exerted to the diaphragm 6, deformation of the diaphragm 6 is suppressed below the elastic limit. Moreover, configuring the diaphragm 6 with a waterproof material prevent intrusion of water to the inside so as to enhance the waterproof performance of the electroacoustic transducer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electroacoustic transducer functioning as a microphone or a speaker.

[0002]

2. Description of the Related Art An electro-acoustic transducer, particularly an electro-acoustic transducer for a cellular phone, basically has a case composed of an upper case and a lower case, and a vibration carrying a yoke and a coil divided into at least two parts. And a magnet having a plate.

The diaphragm has at least one annular peripheral portion and a spherical or dome-shaped central portion, and the outer edge of the diaphragm is fixedly fixed or adhered between an upper case and a lower case. .

A coil is fixed at a boundary between the peripheral portion and the central portion. The coil can be fixed to the diaphragm directly or indirectly via a coil carrier (which can be omitted by specially configuring the diaphragm). The coil projects into an annular gap formed between the divided yokes.
With this configuration, the electro-acoustic transducer functions as a microphone or a speaker.

[0005] It is to be noted that German Patent Publication No. 393 is published.
Japanese Patent No. 5786 discloses a technique of bonding an elastically deformable elastic body to the lower surface of a concavely curved diaphragm in a speaker in order to avoid a so-called resonance peak in a high frequency band.

US Pat. No. 4,399,334 discloses that in a speaker, in order to prevent the coil from completely falling out of the slit area, a stopper is provided on the speaker cover so as to be directed toward the diaphragm so that the diaphragm is moved from the slit. Techniques have been disclosed for limiting the maximum height at which a person exits.

[0007]

However, in such an electro-acoustic transducer, when a large pressure acts on the diaphragm, the mechanical stability of the diaphragm may become a problem. In other words, when pressure is applied to the diaphragm, the diaphragm is elastically deformed, but when excessive pressure acts on the diaphragm, the diaphragm is deformed beyond its elastic limit, and even when the pressure is reduced, the diaphragm remains in its original shape. Will not return to.

Further, the water resistance required for electronic equipment to which such an electro-acoustic transducer is applied has been increased. However, in order to satisfy the required water resistance, it is found in mobile phones and microphones. In such a case, it is necessary to take measures such as a protective cover or a special configuration, which causes a reduction in the use value of the product in a normal use state.

The present invention has been made in view of the above technical problems, and provides an electroacoustic transducer which can maintain mechanical stability even when a large pressure acts and has excellent water resistance. The purpose is to do.

[0010]

According to a first aspect of the present invention, there is provided a diaphragm having a central portion and a peripheral portion, and a coil fixed directly or indirectly to a transition region between the central portion and the peripheral portion. An electroacoustic transducer in which the coil protrudes into an annular gap formed between a first yoke and a second yoke, wherein a supporting member vibrates between the central portion and the second yoke. It is characterized by being arranged at an interval from a plate.

According to a second aspect, in the first aspect, the area of the support member is at least 25% of the area of the second yoke.

According to a third aspect, in the second aspect, the area of the support member is at least 50% of the area of the second yoke.

In a fourth aspect based on the first to third aspects, the distance between the central portion and the support surface of the support member is smaller than a maximum value of a displacement at which the diaphragm can be elastically deformed. It is characterized by the following.

In a fifth aspect based on the first to fourth aspects, the distance between the central portion and the support surface of the support member is larger than the maximum displacement of the diaphragm when the diaphragm vibrates. It is characterized by the following.

In a sixth aspect based on the first to fifth aspects, the distance between the central portion and the support surface of the support member is greater than five times the maximum displacement of the diaphragm when the diaphragm vibrates. Is also large.

In a seventh aspect based on the first to sixth aspects, the distance between the central portion and the support surface of the support member is greater than 10 times the maximum displacement of the diaphragm when the diaphragm vibrates. Is also large.

In an eighth aspect based on the first to seventh aspects, the diaphragm is made of a water-resistant material, for example, recarbonite.
It is characterized by being composed of plastics such as polyetherester urethane, PETP foil, Mylar and the like.

According to a ninth aspect, in the first to eighth aspects, a support member is provided also for the peripheral portion.

According to a tenth aspect, in the ninth aspect, the support member provided to the peripheral portion is constituted by a projecting portion projecting radially from the case.

According to an eleventh aspect, in the tenth or eleventh aspect, a support surface of a support member provided to the peripheral portion extends substantially parallel to the peripheral portion. Things.

[0021]

According to the present invention, a support member is provided at a distance from the diaphragm between the center of the diaphragm and the second yoke below the diaphragm. Accordingly, even if a large pressure acting at a depth of several meters acts on the diaphragm, the deformation of the diaphragm is suppressed below the elastic limit by the support member, and the diaphragm becomes flat with respect to the second yoke below. Deformation to prevent returning to the original shape is prevented.

Here, the distance between the diaphragm and the support member when the same pressure acts on both sides of the diaphragm needs to be larger than the maximum displacement (minimum allowable distance) of the diaphragm when the diaphragm vibrates. There is. The maximum displacement of the diaphragm can be easily calculated based on the configuration of the diaphragm used and the response of the diaphragm to the generated sound wave (in the case of a microphone) or the maximum current (in the case of a speaker or a hearing aid).

Further, it is necessary that the distance be smaller than the distance (maximum allowable distance) at which the diaphragm starts to undergo irreparable deformation. This distance can also be easily obtained by calculation or a simple experiment. Since the interval between the two allowable intervals is relatively wide, there is no problem even if the support member is relatively slightly away from the diaphragm. The distance between the diaphragm and the supporting member is set to twice, preferably three times, particularly preferably ten times the minimum allowable distance.

The support member does not need to cover the entire lower surface of the central portion of the diaphragm, but only needs to cover an advantageously circular region of the central portion, and the diameter of the region is below the central portion of the diaphragm. It is at least 20%, preferably at least 40%, more preferably at least 80% of the diameter of a certain yoke. The area of the support surface of the support member achieved by this is 4 times the area of the yoke.
%, 16% or more, and 64% or more.

The support members can be formed according to the desired acoustic properties of the transducer. Therefore, the contact surface (referred to as the lower surface of the diaphragm and the support surface of the support portion in contact with each other in the present specification) can be formed so as to be “dense” or “permeable”.

Here, "dense" means a contact surface that does not substantially transmit air, and "permeability" means all contact surfaces that allow air to pass. For example, a lattice-like or comb-like structure, a skeleton-like column (like an umbrella bone), etc. can be considered as the transparent contact surface, and a plate made of plastic or metal can be considered as the dense contact surface.

As can be seen from the above description, considering the possibility of providing various holes or holes of different sizes or the possibility of not providing holes until a solid net shape is obtained,
There is a contact surface in a state intermediate between the above “dense” and “permeable”.

The acoustic friction that affects the properties of the transducer is determined by the geometry and permeability of the support member. Thus, by appropriately configuring the support member, the desired properties can be improved over conventional or generally initial ones.

If a water-resistant material such as a well-known plastic such as polycarbonate, polyetherester urethane, PETP foil, or Mylar is used as a material for the diaphragm, water can be prevented from entering the inside, and The water resistance of the acoustic transducer is improved.

Further, a suitable supporting member can be provided on the annular peripheral portion of the diaphragm. In this case, the support member has a donut shape having an undeformed edge, and the contact surface has a shape corresponding to the peripheral edge. What is described with respect to the central portion of the diaphragm in this specification can be applied to the peripheral portion of the diaphragm with a necessary change.

[0031]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows a cross section of an electroacoustic transducer according to the present invention. The electroacoustic transducer has a case including an upper case 1 and a lower case 2. Magnet 3 in lower case 2
Are supported by a lower yoke 4 (first yoke), and the magnet 3 carries an upper yoke (second yoke). The lower yoke 4 has a pot shape with an upper edge drawn inward. An annular gap 1 between the lower yoke 4 and the upper yoke 5
1 is formed.

The diaphragm 6 is fixed and / or bonded between the upper case 1 and the lower case 2. Diaphragm 6
Has a peripheral portion 7 and a central portion 8, and a coil 9 is fixed, for example, adhered to a transition region between the peripheral portion 7 and the central portion 8. The coil 9 has an annular gap 1 between the yokes 4 and 5.
Projecting into one. The coil 9 may be fixed to the diaphragm 6 indirectly via a coil carrier.

According to the present invention, the support member 10 is provided in the space below the central portion 8 of the diaphragm 6. In this embodiment, the support member 10 has a mushroom shape, and the leg 1
0a. The support member 10 is provided by the legs 10a.
Are fixed to, for example, bonded to the upper yoke 5.

The support member 10 can have another structure, for example, a cushion-like structure having a large contact surface with the upper yoke 5. The upper yoke 5 has a circular shape together with the lower yoke 4 to form an annular gap 11 from which the coil 9 projects.

For the same reason, the size of the surface of the upper yoke 5 completely corresponds to the size of the surface of the central portion 8 of the diaphragm 6, so that the sizes of both surfaces must not differ.

The distance between the diaphragm 6 and the supporting member 10 when the same pressure acts on both sides of the diaphragm is larger than the maximum displacement (minimum allowable distance) of the diaphragm when the diaphragm 6 vibrates. In addition, the distance is set to be smaller than the distance (maximum allowable interval) at which the diaphragm 6 causes irrecoverable deformation. Specifically, the interval between the diaphragm 6 and the support member 10 is set to twice, preferably three times, and more preferably ten times the minimum allowable interval.

In this embodiment, the diameter of the support member 10 formed in a circular shape is almost 100% of the diameter of the upper yoke 5.
However, as described above, this is not always necessary.

The portion of the support member 10 that contacts the diaphragm 6 is indicated by a continuous line in FIG. 1, but does not indicate the transmittance of the contact surface. This transmittance can be arbitrarily selected over a wide range as described above, or can be selected depending on desired acoustic characteristics.

In this embodiment, no support member is provided for the peripheral portion 7 of the diaphragm 6, but a support member may be provided in this region. In this case, if the lower case 2 is formed of plastic and the support member is integrally formed with the case 2 in the form of a rib extending in the radial direction, the manufacturing can be performed at low cost.

The manner in which the diaphragm 6 and, in particular, the coil 9 are fixed to the diaphragm is the same as that of the well-known one, so that the detailed description is omitted here. In addition, although there exist many modifications and improvements in the prior art, they do not affect the present invention.

It is important for the present invention to keep the deformation of the diaphragm within the elastic range even when an excessive pressure is applied, so that the shape of the case is changed to another shape without affecting the present invention. It is also possible to configure.

Although the electroacoustic transducer shown here is not used in water, the diaphragm 6 is made of water resistant material such as plastic such as polycarbonate, polyetherester urethane, PETP foil, and Mylar. If it is made of a material, water will not enter the inside of the diaphragm 6, and this kind of equipment, for example, a handy machine (mobile phone)
Can be used again by shaking off the water that has entered between the upper case 1 and the diaphragm 6 after being taken out of the water.

[Brief description of the drawings]

FIG. 1 is a sectional view of an electroacoustic transducer according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Upper case 2 Lower case 3 Magnet 4 Lower yoke (1st yoke) 5 Upper yoke (2nd yoke) 6 Vibration plate 7 Peripheral part 8 Center part 9 Coil 10 Support member

Claims (11)

[Claims] 1. A diaphragm having a central portion and a peripheral portion, and a coil fixed directly or indirectly to a transition region between the central portion and the peripheral portion, wherein the coil is provided with a first yoke and a first yoke. In the electro-acoustic transducer protruding into an annular gap formed between the second yokes, a support member is disposed between the central portion and the second yoke at a distance from the diaphragm. An electroacoustic transducer. 2. The electroacoustic transducer according to claim 1, wherein the area of the support member is at least 25% of the area of the second yoke. 3. The electroacoustic transducer according to claim 2, wherein the area of the support member is at least 50% of the area of the second yoke. 4. The apparatus according to claim 1, wherein a distance between the central portion and a support surface of the support member is smaller than a maximum value of a displacement at which the diaphragm can be elastically deformed. An electroacoustic transducer according to one of the preceding claims. 5. The apparatus according to claim 1, wherein a distance between the central portion and a support surface of the support member is larger than a maximum displacement of the diaphragm when the diaphragm vibrates. An electroacoustic transducer according to any one of claims 1 to 3. 6. The distance between the central portion and the support surface of the support member is set to a maximum displacement of the diaphragm when the diaphragm vibrates.
The electroacoustic transducer according to any one of claims 1 to 5, wherein the electroacoustic transducer is larger than twice. 7. The distance between the central portion and the support surface of the support member is one of the maximum displacement of the diaphragm when the diaphragm vibrates.
The electroacoustic transducer according to any one of claims 1 to 6, wherein the electroacoustic transducer is larger than 0 times. 8. The electroacoustic transducer according to claim 1, wherein said diaphragm is made of a water-resistant material. 9. The electro-acoustic transducer according to claim 1, wherein a supporting member is provided also on the peripheral portion. 10. The electro-acoustic transducer according to claim 9, wherein the support member provided to the peripheral portion is constituted by a projection projecting radially from the case. 11. The electroacoustic transducer according to claim 10, wherein a support surface of a support member provided on the peripheral portion extends substantially parallel to the peripheral portion.