JPH10304491A - Speaker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a clear low sound frequency level through the reproduction of only a low-frequency sound by providing two sounders, made of piezoelectric bodies placed to openings at both ends of a cylindrical main body and a film placed between two cylindrical covers with a bottom to cover the two sounders, so as to reproduce a low-sound frequency regardless of its small size. SOLUTION: At each of both end openings of a cylindrical main body 12 having a 1st opening 18, a 1st damper 16 clamps a sounder 16, a 2nd damper 24 fixes a film 26, and each cover 20 having a 2nd opening 22 is provided. The two sounders 16 are driven by right and left channel stereophonic signals respectively. Thus, a low-frequency sound without a phase difference of the right and left channel signals is radiated from the 1st opening 18 as a double- pressure resonance sound to obtain a sufficient low-frequency sound level regardless of its small size and a clear sound with unpleasant sound components suppressed therefrom is obtained from the 2nd opening 22, because the radiation of the sound wave is attenuated by the film.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a speaker,
In particular, the present invention relates to a speaker which uses a piezoelectric body made of ceramics and is suitable for a 3D center channel woofer which is one of stereo reproduction systems.

[0002]

2. Description of the Related Art Generally, a speaker made of a piezoelectric material uses a piezoelectric material made of ceramics as a sounding body.
The amplitude of the sound wave generated from the sounding body is not so large. Therefore, a speaker made of a piezoelectric material has not been used as a speaker for a woofer that reproduces a bass range.

Accordingly, the present inventor has disclosed in Japanese Patent Application No. Hei.
No. 54 has filed an application for a woofer speaker capable of reproducing bass sound made of a piezoelectric material.

[0004] This speaker will be described with reference to FIG. The speaker 1 includes a cylindrical main body 2 having open portions at both ends. A ring-shaped damper 6 is provided at each of the open portions at both ends of the main body 2, and the sounding body 3 is attached to the damper 6. Is done. A circular first opening 2 a is formed in the center of the side surface of the main body 2. A cylindrical cover 4 with a bottom is provided outside the two sounding bodies 3 so as to cover open portions at both ends of the main body 3, and is fixed so that the inside of the cover 4 is airtight. You. Near the bottom center of the lid 4,
A circular second opening 4a is formed. A sound absorbing material 5 for absorbing and attenuating high frequency components of sound waves is provided inside the main body 2 and inside the lid 4.

The sounding body 3 includes a disk-shaped vibration plate 3a made of metal, and a disk-shaped piezoelectric element 3b as a vibration source is provided at the center of both main surfaces of the vibration plate 3a. Are fixed in concentric circles in a bimorph configuration. Although not shown, the piezoelectric element 3b is configured by forming electrode films on both main surfaces of a disk-shaped piezoelectric body.

The first opening 2 a and the second opening 4 a are both formed so as to be smaller than the area of the diaphragm 3 a of the sounding body 3.

[0007] One of the two sounding bodies 3 is connected to one input terminal (not shown) provided outside the main body 2 via a lead wire (not shown).
Is connected to the main body 2 via another lead wire (not shown).
Is connected to the other input terminal (not shown) provided outside. In this case, when an electric signal from an amplifier (not shown) is input to one input terminal, one of the two sounding bodies 3 vibrates, and an amplifier (not shown) is input to the other input terminal.
, The other of the two sounding bodies 3 vibrates.

Then, the sounding body 3 may be driven so that the pressure inside the main body 2 is simultaneously increased and decreased by the two sounding bodies 3. That is, if one channel signal of a stereo signal, for example, the right channel signal is input to one input terminal, the other channel signal of the stereo signal, that is, the left channel signal may be input to the other input terminal. . By inputting a signal in this manner, 2
A sound wave is generated inside the main body 2 from the three sounding bodies 3 and the main body 2
A sound wave is emitted from the first opening 2a of the
A sound wave is generated inside the cover 4 from the three sounding bodies 3 and the cover 4
A sound wave is emitted from the second opening 4a. At this time,
The area of the first opening 2a of the main body 2 is equal to the diaphragm 3 of the sounding body 3.
a, the amplitude of the sound wave radiated from the first opening 2a of the main body 2 is smaller than that of the two sounding bodies 3
The amplitude of the sound wave is larger than the amplitude of the sound wave generated at this time, and the low sound range is emphasized and emitted. Further, inside the main body 2, the sound waves in the middle and high frequency ranges generated from the two sounding bodies 3 are canceled because the phases are opposite to each other, and only the low frequency range is emphasized and radiated from the first opening 2 a. Is done.

As a result, the speaker 1 can reproduce the low-frequency range by using the piezoelectric body without using a large diaphragm, a large housing, a large baffle plate, and the like. Further, since the sound absorbing material 5 absorbs and attenuates the high-frequency components of the sound waves generated by the two sounding elements 3 inside the main body 2 and the lid 4, the bass range of the reproduced sound waves is further emphasized as a result. Is done.

[0010]

However, in a conventional speaker using a sounding body made of a piezoelectric body, the sounding body is made of a plate-shaped piezoelectric body. The vibration region in the body has a property of being divided into a piston vibration region and a divided vibration region.

In a speaker using the resonance phenomenon,
A resonance phenomenon occurs with respect to a sound wave generated by the piston vibration, but a sound wave generated by the division vibration has a large amount of distortion due to the nature of the division vibration and does not cause the resonance phenomenon.
When the resonance phenomenon does not occur, the bass range is not emphasized, and as a result, the sound wave in the middle and high range is emphasized, and the speaker function for the woofer is not performed.

On the other hand, the above-mentioned conventional speaker using a sounding body made of a piezoelectric body has a resonance phenomenon determined by the volume of the main body and the shape of the first opening, and the volume of the lid and the second opening. The function of a speaker for a woofer utilizing a resonance phenomenon determined by the shape of the part is achieved.

In a conventional speaker, when a sound wave caused by divided vibrations generated from two sounding bodies exists inside the main body, the phases of the middle and high range sound waves generated from each of the two sounding bodies are reversed. Because of the phase, the sound wave in the middle and high range is canceled inside the main body, and the sound wave in the middle and high range caused by the divided vibration is not emitted from the first opening. However, inside the lid, only the sound wave caused by the divided vibration generated from one of the two sounding bodies exists, and unlike the inside of the main body, the sound wave caused by the divided vibration is located in the middle and high frequency range. Sound waves are not canceled.

[0014] Therefore, the middle and high range sound waves resulting from the divided vibration are radiated as they are from the second opening of the lid. This treble range could not be sufficiently absorbed and attenuated even by the sound absorbing material, and as a result, both the treble range and the bass range were radiated from the second opening. In addition, since the sound wave resulting from the divided vibration does not cause a resonance phenomenon, the sound of the woofer speaker is turbid and emits a small sound with a low sound level.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above-mentioned problems, and it is possible to reproduce a low-frequency range with a small size, and to reproduce a clear low-frequency level by reproducing only the low-frequency range. It is to provide a speaker that can be obtained.

[0016]

In order to achieve the above object, a speaker according to the present invention has a tubular main body having open portions at both ends, and vibrates by electric signals provided at open portions at both ends of the main body. Two sounding bodies consisting of piezoelectric bodies and 2
Two lids provided to cover one sounding body and having a bottomed cylindrical shape, a first opening provided on a side surface of the main body, and a second opening provided on a bottom surface of the lid. A speaker having two sounding bodies driven in a direction in which the internal pressure of the main body and the internal pressure of the lid increase and decrease, wherein a film is provided between the sounding body and the second opening inside the lid. It is characterized by having a body.

Thus, in the lid, sound waves caused by the divided vibration generated from one of the sounding bodies are attenuated by the film body acting as a wall, so that the sound waves are attenuated and the sound waves are transmitted to the film body. , The displacement of the sound wave caused by the divided vibration is averaged, converted into a sound wave without distortion, and then radiated outside from the second opening to the lid. Therefore, unpleasant and unpleasant sound as a speaker for a woofer can be suppressed, and reproduced as clear sound.

[0018]

Embodiments of the present invention will be described below in detail with reference to the drawings. 1 and 2 show a speaker according to a first embodiment of the present invention. Speaker 10
Includes a cylindrical body 12 having open portions at both ends. A ring-shaped first damper 1 is provided at both ends of the main body 12.
The sounding body 16 is sandwiched between the first dampers 14 and 14 and is fixed so that the inside of the main body 12 is airtight. Then, a circular first opening 18 is formed in the center of the side surface of the main body 12. A ring-shaped second damper 24 is fixed to the first damper 14 in a direction approaching the opening of the main body 12 from the sounding body 16, and a disk-shaped film 26 is fixed to the second damper 24. In addition, the cylindrical body 20 with a bottom is provided on the film body 26. The lid 20 is fixed so as to cover the open portion of the main body 12 and to make the inside of the lid 20 airtight. A circular second opening 22 is formed near the center of the bottom surface of the lid 20. In this way, the film body 26 is located between the second opening 22 of the lid 20 and the sounding body 16.

Here, the main body 12 and the lid 20 are made of, for example, a synthetic resin material such as plastic, or a material obtained by cutting wood into a cylindrical shape.

The sounding body 16 includes, for example, a disk-shaped diaphragm 16a made of metal, and a disk-shaped piezoelectric element 16b as a vibration source is provided at the center of both main surfaces of the diaphragm 16a. Each is fixed in a bimorph configuration on the concentric circle 16a. Although not specifically shown, the piezoelectric element 16b is configured by forming electrode films on both main surfaces of a disk-shaped piezoelectric body.

The first damper 14 and the second damper 24 are preferably made of a material having a large mass.

The film 26 is preferably made of a resilient material such as a silicon rubber sheet.

Although not shown, the speaker 10
Is such that the first opening 18 of the main body 10 faces downward.
It is mounted on a mounting table (not shown).

One of the two sounding bodies 16 is connected to one input terminal (not shown) provided outside the main body 12 via a lead wire (not shown). The other, via another lead (not shown)
It is connected to the other input terminal (not shown) provided outside the main body 12. In this case, when an electric signal from an amplifier (not shown) is input to one input terminal, one of the sounding bodies 16 vibrates, and an electric signal from the amplifier (not shown) is input to the other input terminal. Is input, the other of the sounding bodies 16 vibrates.

In the speaker 10 configured as described above,
The sounding body 16 may be driven so that the pressure inside the main body 12 is simultaneously increased and decreased by the two sounding bodies 16. That is,
If one channel signal of a stereo signal, for example, the right channel signal is input to one input terminal, the other channel signal of the stereo signal, that is, the left channel signal may be input to the other input terminal. By inputting a signal in this manner, sound waves are generated from the two sounding bodies 16 inside the main body 12, and resonance occurs between the main body 12 and the first opening 18. Only the resonance sound generated by this resonance is radiated out of the main body 12 from the first opening 18. Here, the first opening 18 of the main body 12 is provided.
, The low frequency range in which there is no phase difference between the right channel signal and the left channel signal is radiated out of the main body 12 as a doubled resonance sound obtained by combining the right channel signal and the left channel signal, Since a sufficient sound pressure can be obtained even if the main body 12 is made smaller, the speaker 10 which emits a sufficiently low sound level even when it is small can be obtained. In the middle and high frequency range having a phase difference between the right channel signal and the left channel signal, the right channel signal and the left channel signal are combined and canceled, so that the low frequency range of the radiated sound wave is further emphasized. Is done.

A sound wave is also generated inside the cover 20 from the two sounding bodies 16, and resonance occurs between the cover 20 and the second opening 22, and only the resonance sound generated by the resonance is generated.
The light is radiated from the second opening 22 to the outside of the lid 20.

In the speaker 10 of the present invention, the sounding body 1
6 is made of a plate-shaped piezoelectric material, and has a property that a vibration region in the sounding body 16 is divided into a piston vibration region and a divided vibration region according to the frequency of a signal input to the sounding body 16. The sound wave generated from the piston vibration region of the sounding body 16 has a resonance phenomenon, but the sound wave generated from the divided vibration region has many distortions due to the nature of the divided vibration, and does not cause the resonance phenomenon. .

Here, when there is a sound wave due to the divided vibration generated from the two sounding bodies 16 inside the main body 12, the phases of the middle and high range sound waves generated from each of the two sounding bodies 16 are reversed. Because of the phase, the sound wave in the middle and high range is canceled inside the main body 12, and the sound wave in the middle and high range due to the divided vibration is not emitted from the first opening 18. In addition, inside the lid 20, only sound waves caused by the divided vibration generated from one of the sounding bodies 16 of the two sounding bodies 16 are present, and unlike the inside of the main body 12, the sound waves are caused by the divided vibration. The sound wave in the mid-high range of the sound wave is not canceled. However, due to the film 26 provided between the lid 20 and the second opening 22,
The sound wave caused by the divided vibration generated from one sounding body 16 is attenuated by the sound wave radiation attenuated by the film body 26 serving as a wall, and also caused by the divided vibration by the sound wave hitting the film body 26. The displacement of the moving sound wave is averaged and converted into an undistorted sound wave.
Is radiated to the outside from the opening 22 of the second member. Therefore, unpleasant and unpleasant sounds as the speaker 10 can be suppressed, and reproduced as clear sounds.

The film 26 is formed in the second opening 22.
It has a function of protecting the sounding body 16 from dust and the like entering the speaker and protecting the sounding body from environmental changes such as a change in humidity around the speaker 10.

Although not specifically shown, a sound absorbing material made of glass wool or the like may be provided inside the main body 12 or inside the lid 20, whereby a sound wave generated inside the main body 12 or inside the lid 20 may be provided. As it absorbs and attenuates the mid-high range,
The bass range of the reproduced sound wave is further emphasized.

When an electric signal is input to the sounding body 16 so that the pressure inside the main body 12 is increased or decreased by the two sounding bodies 16, a sound wave is generated from the sounding body 16 inside the main body 12,
Sound waves are emitted outward from the first opening 18 of the main body 12. In this case, the diameter of the first opening 18 is set smaller than that of the sounding body 18, and thus the first opening 1
The amplitude of the sound wave radiated from 8 is larger than the amplitude of the sound wave generated from the sounding body 16. For this reason, the speaker 10 of the present invention uses a plate-shaped piezoelectric body as a sounding body, and is smaller and thinner than a sounding body using a cone plate or the like used in a conventional woofer speaker. In addition to the miniaturization of the speaker 10, the speaker 10 for a woofer reproduces a sufficiently low sound level.

One body 12 is provided with two sounding bodies 16.
And outputs the sum output of the right channel signal and the left channel signal.
In addition, since an acoustic low-pass filter is configured by using only the sound pressure from the opening provided in the lid 20, a simple structure, an inexpensive, and sufficient low-frequency range can be obtained. The speaker 10 is suitable for a center channel woofer of a system.

In the above-described embodiment, the main body is formed in a cylindrical shape, but the main body may be formed in a cylindrical shape other than the cylindrical shape, for example, a rectangular cylindrical shape. Similarly, the lid body may be formed in a bottomed cylindrical shape other than the bottomed cylindrical shape, for example, a bottomed square tubular shape.

The vibration plate and the piezoelectric element constituting the sounding body are not limited to the disk shape, but may be formed in other shapes such as a square plate shape.
It may be formed of rubber or synthetic resin.

Although the film body and the second damper are formed separately, they need not be formed separately, and the film body and the second damper may be integrally formed.

Further, the present invention is not limited to a sounding body using a bimorph structure piezoelectric element, but also a sounding body using a unimorph structure piezoelectric element, or a laminated structure using three or more laminated piezoelectric layers made of ceramics. For example, a sounding body using the above piezoelectric element may be used.

[0037]

As described above, in the loudspeaker according to the present invention, the sound wave caused by the divided vibration generated from one sounding body in the lid is radiated by the film body acting as a wall. Is attenuated, and the sound waves impinge on the membrane, so that the displacement of the sound waves due to the divided vibrations is averaged and converted into sound waves without distortion, and then the sound waves are transmitted through the second opening provided in the lid. Radiated to the outside. Therefore, unpleasant and unpleasant sound as a speaker for a woofer can be suppressed, and reproduced as clear sound.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a structure of a speaker according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a structure of the speaker according to the embodiment of the present invention.

FIG. 3 is a cross-sectional view illustrating a structure of a conventional speaker.

[Explanation of symbols]

 Reference Signs List 10 speaker 12 main body 16 sounding body 18 first opening 20 lid 22 second opening 26 film body

Claims (1)

[Claims] 1. A cylindrical main body having open portions at both ends, two sounding members provided at open portions at both ends of the main body, each of which is made of a piezoelectric material and vibrates by an electric signal, so as to cover the two sounding members. There are provided two lids each having a bottomed cylindrical shape, a first opening provided on a side surface of the main body, and a second opening provided on a bottom surface of the lid. A speaker configured to drive the two sounding members in a direction in which the internal pressure of the main body and the internal pressure of the lid increase and decrease, wherein the speaker and the second opening are provided inside the lid. A speaker characterized in that a film is provided between the speaker and the speaker.