JP2001103587A - Acoustic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the localization of a sound field of an acoustic device employing a piezoelectric vibrator. SOLUTION: A couple of left and right acoustic diaphragms 20 are placed in parallel with both sides of a chair 50 having at least a seat section 52 and legs 56, the piezoelectric vibrator 10 is fitted to each of the acoustic diaphragms 20 and a sound signal is applied to the piezoelectric vibrators 10 to deliver the vibration generated by the piezoelectric vibrators 10 to the acoustic diaphragms 20 so that the sound wave is mainly propagated to the sides of the chair.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an acoustic device, and more particularly to an acoustic device in which piezoelectric speakers are arranged on both sides of a chair.

[0002]

2. Description of the Related Art A sound generating device having a piezoelectric vibrator as a sound source of a speaker system is known. For example, Japanese Utility Model Registration No. 3037167 filed by the present applicant discloses a speaker structure using a piezoelectric vibrator made of a piezoelectric element such as a bimorph as a sound source of a speaker system. In this loudspeaker, a piezoelectric vibrator is attached to an acoustic diaphragm made of fiber reinforced plastic such as carbon fiber to use as a sound source of the speaker.

[0003]

On the other hand, it is known that the acoustic characteristics of a speaker have directivity. Due to the directivity of the loudspeaker, if the sound propagating from the loudspeaker is directly heard, the audible sound changes due to a change in the relative position between the listener and the speaker. This is particularly noticeable in stereo reproduction. In other words, the optimum position for listening to the sound field reproduced by the loudspeaker is uniquely defined, and if the position deviates from that position, the localization of the sound field is deteriorated and the stereo effect cannot be sufficiently exhibited. There's a problem.

An object of the present invention is to solve such a problem, and an object of the present invention is to improve the localization of a sound field of an acoustic device using a piezoelectric vibrator.

[0005]

According to the present invention, a pair of left and right acoustic diaphragms are arranged in parallel on both sides of a chair having at least a seat surface and a leg, and each of the acoustic diaphragms is provided with a piezoelectric vibrating plate. A sound device in which a body is attached, a sound signal is applied to the piezoelectric vibrating body, vibration generated by the piezoelectric vibrating body is transmitted to the acoustic diaphragm, and a sound wave is mainly propagated to the side of the chair. Make a summary.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, a chair 50 according to this embodiment has a seat portion 52, a backrest portion 54 connected to the seat portion 52, and acoustic diaphragms provided on both sides of the seat portion 52. And a frame 56 for the 20. The frame 56 also constitutes a handrail and a leg of the chair 50 at the same time. The acoustic diaphragm 20 can include a composite material in which carbon fibers or glass fibers are bonded with a resin, or a synthetic resin material such as expanded polypropylene or expanded styrene. At least one piezoelectric vibrating body 10 is attached to the acoustic diaphragm 20.

Referring to FIG. 2, a sound generator according to an embodiment of the present invention includes a piezoelectric vibrator 10 attached to a surface of an acoustic diaphragm 20 formed of, for example, carbon fiber reinforced plastic. The piezoelectric vibrating body 10 has a piezoelectric vibrating plate 12 such as a bimorph formed in a circular shape, and an annular vibration control piece 14 is attached along the outer peripheral edge of one side surface of the piezoelectric vibrating plate 12. I have. The vibration control piece 14 can be formed of, for example, rubber or plastic. The piezoelectric vibrator 10 has a foot 16 at its center.
It is attached to the surface of the acoustic diaphragm 20 by a mounting member 16 having a and a nut 18. The space between the foot 16a and the acoustic diaphragm 20 can be fixed with an adhesive.

Although FIG. 1 shows three piezoelectric vibrators 10 attached to each of a pair of left and right acoustic diaphragms 20, the present invention is not limited to this, and one or two or Four or more piezoelectric vibrators 10 can be attached. Although not specifically shown, a dynamic speaker may be provided below the seat 52.

Hereinafter, the operation of the present embodiment will be described. FIG.
As shown in FIG. 1, a pair of left and right acoustic diaphragms 20 are arranged on both sides of a chair 50 in parallel with each other, and the piezoelectric vibrating body 10 is attached to each of the acoustic diaphragms 20. When an audio signal is applied to the piezoelectric vibrator 10 from an amplifier (not shown), the piezoelectric vibrator 10 vibrates according to the audio signal. This vibration is transmitted to the acoustic diaphragm 20 via the mounting member 16,
Sound waves are propagated from the acoustic diaphragm 20 to the surroundings.

At this time, the sound pressure of the sound wave emitted from the acoustic diaphragm 20 becomes maximum in a direction perpendicular to the acoustic diaphragm 20 and becomes minimum in a direction parallel to the acoustic diaphragm 20. Therefore, in the direction of the person sitting on the chair 50, the acoustic diaphragm 20
When the chair 50 is placed in a room, for example, a person sitting on the chair 50 can reduce sound waves emitted from the acoustic diaphragm 20 more than the sound waves emitted directly from the acoustic diaphragm 20.
0, the sound wave reflected on the floor surface 62 is heard. Thereby, the directivity of the sound generated from the acoustic diaphragm 20 is reduced, and a stable sound field is formed around the person sitting on the chair 50.

Further, preferably, the phase of the audio signal applied to the pair of left and right piezoelectric vibrators 10 provided on both sides of the chair 50 is generated with a phase shifted by 周期 cycle. Thereby, the sound wave generated by the acoustic diaphragm 20 is minimized in the middle of the pair of left and right acoustic diaphragms 20, and the sound pressure of the sound directly propagating from the acoustic diaphragm 20 around the person sitting on the chair 50 is improved. It becomes possible to reduce.

[Brief description of the drawings]

FIG. 1 is a perspective view of an acoustic device according to a preferred embodiment of the present invention.

FIG. 2 is an enlarged sectional view of a piezoelectric vibrator.

FIG. 3 is an explanatory diagram in a case where an acoustic device is arranged in a room.

[Explanation of symbols]

 10: Piezoelectric vibrator 20: Acoustic diaphragm 50: Chair

Claims (3)

[Claims] 1. A pair of left and right acoustic diaphragms are arranged in parallel on both sides of a chair having at least a seat surface and a leg, and a piezoelectric vibrator is attached to each of the acoustic diaphragms. A sound signal is applied to the acoustic vibration plate to transmit a vibration generated by the piezoelectric vibrating body to the acoustic diaphragm, so that a sound wave is mainly propagated to the side of the chair. 2. The acoustic device according to claim 1, further comprising a dynamic speaker arranged below the seat portion. 3. The acoustic device according to claim 1, wherein the chair further has a backrest portion.