JP2000032583A - Electroacoustic transducer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain with a simple configuration an electroacoustic transducer that conducts satisfactory electroacoustic conversion containing low sound band. SOLUTION: This electroacoustic transducer having a diaphragm 6 is provided with a vibrator 10 placed to the diaphragm 6, and the vibrator 10 generates an operating force in the direction opposite to a sound radiation of the diaphragm 6, by allowing the vibrator 10 to use a reaction of sound radiation of the diaphragm 6. The vibrator 10 is placed at the top of the diaphragm 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electro-acoustic converter suitable for use in a dynamic headphone driver and a dynamic microphone.

[0002]

2. Description of the Related Art
A dynamic headphone driver as shown in FIG. 2 has been proposed as a dynamic headphone driver used for a headphone as an electric / acoustic converter.

In this dynamic headphone driver, as shown in FIG. 2, a ring-shaped magnet is provided, and a pole piece 2 made of a ring-shaped plate is provided above the ring-shaped magnet 1.
Is fixed to the bottom of the pot-shaped yoke 3 having a U-shaped cross section and a flange-shaped frame portion 3a at the outer periphery of the upper end of the pot-shaped magnetic circuit.

In this case, a through-hole 9 is formed to penetrate the center of the bottom of the pot-shaped yoke 3, the center of the ring-shaped magnet 1, and the center of the pole piece 2.

In this case, a ring-shaped magnet circuit is constituted by the ring-shaped magnet 1, the pole piece 2 and the pot-shaped yoke 3, and a magnetic gap 4 is provided between the pole piece 2 and the upper end of the pot-shaped yoke 3. To form

A diaphragm ring 5 is attached to a free end of a flange-shaped frame portion 3a provided continuously with the pot type yoke 3.
And a voice coil 7 fixed between the dome portion 6a and the edge portion 6b of the diaphragm 6 is fixed to the pole piece 2 and the upper end of the pot type yoke 3. It is inserted into the magnetic gap 4 formed between them.

As the diaphragm 6, a thin film such as a polyester film is used. Although not shown, a lead wire of the voice coil 7 is fixed to the diaphragm ring 5, and the lead wire from this fixing portion is connected to an input terminal provided at the bottom of the pot-shaped yoke 3.

Further, a predetermined number of openings 3 b are provided in a flange-shaped frame portion 3 a continuous with the pot-shaped yoke 3, and a protective cap 8 having a predetermined number of openings 8 a is provided so as to cover the diaphragm 6.

In such a headphone dynamic headphone driver, the sound radiation force F ₁ due to the vibration of the diaphragm 6 is obtained by multiplying the effective mass M ₁ of the vibration system of the dynamic headphone driver by the moving acceleration α ₁ of the diaphragm 6. in other words, Arawaseru in F ₁ = M ₁ α _1.

This sound radiation force F ₁ is generated, and if this force is defined as the acting force F ₁ , the reaction force is generated in the opposite direction of the acting force F ₁ with the same magnitude. The power of this reaction to -F _1. In the case of these headphones, the housing is very light, and the force of pressing against the ear cannot be practically increased.

For this reason, in the dynamic headphone driver of this headphone, the reaction force −F ₁
The air in the headphones repeatedly compresses and expands, and the air acts as a force to return the diaphragm 6 to its original position. There was an inconvenience that could not radiate powerful clear bass.

In view of the foregoing, it is an object of the present invention to provide an air-to-sound converter, such as a dynamic headphone driver, which can perform good low-frequency sound-to-sound conversion with a simple configuration.

[0013]

According to the present invention, there is provided an electro-acoustic converter having a diaphragm provided with a vibrator, the vibrator driving a reaction force of sound radiation of the diaphragm. As a force, an acting force in a direction opposite to the sound radiation direction of the diaphragm is generated.

According to the present invention, the diaphragm is provided with the vibrating body, and the vibrating body generates the acting force by using the reaction force in the direction opposite to the sound radiation direction of the diaphragm as the driving force. The sound radiation force of the diaphragm can be offset by the acting force of the vibrator, and a powerful and clear bass can be obtained.

Further, in the present invention, since the vibrating body is provided on the diaphragm, if the resonance frequency of the vibrating body is set to be slightly higher than the bass resonance frequency, the bass resonance frequency can be lowered and a lower sound can be obtained. it can.

[0016]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of an electric / acoustic converter according to an embodiment of the present invention; In FIG. 1, portions corresponding to FIG. 2 are denoted by the same reference numerals.

FIG. 1 is a sectional view of a dynamic headphone driver used for a headphone as an electric / acoustic converter of the present embodiment.

As shown in FIG. 1, the dynamic headphone driver of this embodiment has a ring-shaped magnet 1 and a pole piece 2 made of a ring-shaped plate provided above the ring-shaped magnet 1.
Is fixed to the bottom of the pot-shaped yoke 3 having a U-shaped cross section and a flange-shaped frame portion 3a at the outer periphery of the upper end of the pot-shaped magnetic circuit.

In this case, a through hole 9 penetrating through the center of the bottom of the pot-shaped yoke 3, the center of the ring-shaped magnet 1, and the center of the pole piece 2 is formed.

In this case, the ring-shaped magnet 1, the pole piece 2, and the pot-shaped yoke 3 constitute a pot-shaped magnetic circuit, and a magnetic gap 4 is provided between the pole piece 2 and the upper end of the pot-shaped yoke 3. To form

The end of the edge 6b of the diaphragm 6 is fixed to the free end of the flange-shaped frame 3a provided continuously with the pot type yoke 3 via the diaphragm ring 5, and the dome 6a of the diaphragm 6 Edge 6
b and a voice coil 7 fixed between the pole piece 2 and the upper end of the pot-shaped yoke 3.
So that it can be inserted into

As the diaphragm 6, a thin film such as a polyester film is used. Although not shown, a lead wire of the voice coil 7 is fixed to the diaphragm ring 5, and the lead wire from this fixing portion is connected to an input terminal provided at the bottom of the pot-shaped yoke 3.

Further, a predetermined number of openings 3b are provided in a flange-shaped frame portion 3a continuous with the pot-shaped yoke 3, and a protective cap 8 having a predetermined number of openings 8a is provided so as to cover the diaphragm 6.

In this embodiment, as shown in FIG. 1, a vibrating body 10 is fixedly attached to the top of the dome 6a of the diaphragm 6. For example, a predetermined amount of an ultraviolet curable resin is applied as the vibrator 10. When an ultraviolet curable resin is used as the vibrating body 10, manufacturing becomes easy.

The mass M ₂ of the vibrating body 10 is set to be substantially the same as the effective mass of the diaphragm 6.

In this case, the vibrating body 10 fixed to the top of the dome portion 6a of the diaphragm 6 utilizes the elasticity (stiffness) of the dome portion 6a of the diaphragm 6 to cause a reaction in the direction opposite to the sound radiation direction. a force -F ₁ generates a sound emission direction opposite to the direction of the acting force F ₂ as a driving force.

In this embodiment, the sound radiation force caused by the vibration of the diaphragm 6 is F ₁ , and the vibrating body 10 generates a reaction force −F _{1 in the} direction opposite to the sound radiation direction of the sound radiation force F ₁ of the diaphragm 6. when the acting force of the sound radiating direction opposite that occurs as driving force was _{F 2, F 1 ≒ F 2} ‥‥ (1) to as holds.

Here, the acting force F ₂ is given by F ₂ = M ₂ α ₂ ‥‥ (2) where α ₂ is the moving acceleration of the vibrating body 10, and the sound radiation force F ₁ of the diaphragm 6 is , F ₁ = M ₁ α ₁ ‥‥ (3), and the moving acceleration α ₁ of the diaphragm 6 and the vibrating body 10
Since the moving acceleration α ₂ is equal, the mass M ₂ of the vibrating body 10 may be approximately the effective mass M ₁ of the diaphragm 6 to satisfy the expression (1).

In this embodiment, by satisfying the above expression (1), the sound radiation force F ₁ of the diaphragm 6 can be offset by the acting force F ₂ of the vibrating body 10, and a clear and powerful low tone can be produced. Obtainable.

Therefore, according to the present embodiment, a powerful and clear bass can be obtained with a simple structure for attaching and fixing the vibrating body 10 to the diaphragm 6.

In this embodiment, when the elastic coefficient of the diaphragm 6 is k, the resonance frequency f
Is Becomes In the present example, the resonance frequency f is slightly above the bass resonance frequency f ₀ of the dynamic headphone driver of the headphone.

At this time, the mass M by the vibrating body 10
₂ is the effective mass of dynamic headphone driver M ₁
A motion in the same direction, bass resonance frequency f ₀ of the dynamic headphone driver, And the bass resonance frequency when the above configuration is not used , The bass resonance frequency can be lowered, and bass can be reproduced. Where S is diaphragm 6
Is the stiffness of the dome portion 6a.

In the above-described embodiment, the example in which the vibrating body 10 is provided at the apex of the dome portion 6a of the diaphragm 6 has been described.
Instead, the vibrating body may be equally divided and disposed at a plurality of, for example, three, locations at the apex of the edge 6b of the diaphragm 6 at equal intervals. In this case, it is needless to say that the same operation and effect as in the above-described example can be obtained.

In the above-described embodiment, an example in which the present invention is applied to a dynamic headphone driver has been described. However, it can be easily understood that the present invention can be applied to a dynamic microphone having the same configuration as the dynamic headphone driver.

Further, the present invention is not limited to the above-described example, but may adopt various other configurations without departing from the gist of the present invention.

[0036]

According to the present invention, the diaphragm is provided with a vibrating body, and the vibrating body generates an acting force by using a reaction force in a direction opposite to the sound radiation direction of the diaphragm as a driving force, so that the diaphragm is simple. With the configuration, the sound radiation force of this diaphragm can be offset by the action force of this vibrator,
There is an advantage that powerful clear bass can be obtained.

Further is provided with the vibrating body to the diaphragm in the present invention, the resonance frequency f of the vibrator, if slightly larger than the bass resonance frequency f _0, it is possible to lower this bass resonance frequency f _0, and more There are benefits to getting bass.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating an example of an embodiment of an electro-acoustic converter of the present invention.

FIG. 2 is a cross-sectional view showing an example of a conventional electric / acoustic converter.

[Explanation of symbols]

1 ring magnet, 2 pole piece, 3 mm
‥ pot type yoke, 3a ‥‥ frame part, 4 ‥‥ magnetic gap, 5 ‥‥ diaphragm ring, 6 ‥‥ diaphragm,
6a dome, 6b edge, 7 voice coil, 8 protective cap, 10 vibrator

Claims (3)

[Claims] 1. An electro-acoustic conversion device having a diaphragm, wherein a vibrating body is provided on the diaphragm, and the vibrating body uses a reaction force of sound radiation of the diaphragm as a driving force in a direction opposite to a sound radiation direction of the diaphragm. An electric / acoustic converter characterized by generating an acting force. 2. The electro-acoustic conversion device according to claim 1, wherein the vibrator is provided at an apex of a dome of the diaphragm. 3. The electro-acoustic converter according to claim 2, wherein the mass of the vibrator is substantially the same as the effective mass of the diaphragm.