JP2004015282A - Speaker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a speaker capable of extending choice of materials configuring the speaker and solving the problem caused by fixing a dome shaped sounder and a base member by an adhesive. <P>SOLUTION: The speaker 10 includes a base disk member 12. A ring shaped buffer member 16 is bonded to a recessed part 14 of the base member 12 by the adhesive. The dome shaped sounder 20 is bonded to the buffer member 16 by the adhesive. The sounder 20 comprises a dome shaped thin vibrator 22 made of a piezoelectric body and electrodes 24, 26. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a speaker, and more particularly, to a speaker using, for example, a hemispherical sounding body.
[0002]
[Prior art]
FIG. 6 is an illustrative sectional view showing an example of a conventional speaker. The speaker 1 includes a sounding body 2. The sounding body 2 includes a thin hemispherical or dome-shaped vibrating body 3 formed of a piezoelectric material such as a piezoelectric ceramic. Electrodes 4a and 4b are formed on the entire outer surface and inner surface of the vibrating body 3. Therefore, by inputting a signal between the electrodes 4a and 4b, the vibrating body 3 vibrates and emits a sound wave. The edge of the sounding body 2 is bonded to the base member 5 with an adhesive.
[0003]
[Problems to be solved by the invention]
In such a conventional speaker, there is a problem that the sounding body is cracked due to a temperature change because of a difference in thermal expansion coefficient between the sounding body and the base member. The adhesive for fixing the sounding body to the base member has a certain degree of elasticity, and the adhesive functions as a cushion for absorbing a difference in thermal expansion coefficient between the sounding body and the base member. However, a thin adhesive layer has a limit in the effect of absorbing the difference in thermal expansion coefficient between the sounding body and the base member. Therefore, as the material of the base member, a material having a thermal expansion coefficient close to that of the sounding body must be selected, and the material is limited to aluminum or the like, and there are limitations in terms of manufacturing cost and adjustment of speaker characteristics.
[0004]
In addition, the edge of the sounding body does not have to be firmly fixed to the base member, and a certain degree of flexibility is required to dampen vibration of the sounding body and suppress vibration leakage. In a conventional loudspeaker, the adhesive also has a function of suppressing such vibration. However, there is a problem that it is difficult to stably control the amount, adhesive area, thickness, and the like of the adhesive, and it is difficult to stabilize speaker characteristics (sound pressure characteristics). In addition, there is a problem that when the cushioning property is improved by the adhesive, the speaker characteristics deteriorate. Therefore, the selection of the adhesive is also limited, and it is necessary to consider many characteristics such as fixing strength and flexibility.
[0005]
SUMMARY OF THE INVENTION Therefore, a main object of the present invention is to provide a speaker capable of expanding a selection range of materials constituting the speaker and solving a problem caused by fixing the dome-shaped sounding body and the base member with an adhesive. It is to provide.
[0006]
[Means for Solving the Problems]
The present invention supports a sounding body composed of a vibrating body made of a thin dome-shaped piezoelectric body, electrodes formed at opposing positions on an outer surface and an inner surface of the vibrating body, and supports an edge of the sounding body. Including a base member for the speaker, wherein a cushioning material is disposed between an edge portion of the sounding body and the base member.
In such a speaker, one side of the cushioning material and the base member are fixed with an adhesive, and the other surface of the cushioning material and the edge of the sounding body are fixed with an adhesive, so that the cushioning material is sandwiched. The sounding body is supported by the base member.
[0007]
Since the cushioning material has a stable shape and characteristics, in the support between the sounding body and the base member, the influence on the characteristics due to the variation in the thickness and the amount as in the case of supporting with the adhesive is reduced. For this reason, it is possible to suppress variations in speaker characteristics as in the case where the speaker is supported by an adhesive.
Further, the adhesive only needs to play the role of fixing between the cushioning material and the base member and fixing between the cushioning material and the sounding body. Therefore, the adhesive can be selected without considering characteristics such as flexibility.
[0008]
The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description of embodiments of the present invention with reference to the accompanying drawings.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a perspective view showing an example of a speaker according to the present invention, and FIG. 2 is a schematic sectional view thereof. The speaker 10 includes a base member 12. The base member 12 is formed in a disk shape using a metal material such as aluminum or a synthetic resin material such as a phenolic resin. Then, a circular concave portion 14 is formed at the center of one surface of the base member 12.
[0010]
In the concave portion 14 of the base member 12, a ring-shaped cushioning material 16 is arranged along a circular end. The cushioning material 16 is formed of an elastic body such as silicon rubber, for example, and is firmly adhered to the bottom surface of the concave portion 14 by an adhesive 18 as shown in FIG.
[0011]
The sounding body 20 is fixed on the cushioning material 16. The sounding body 20 includes a vibrating body 22 formed of a hemispherical or dome-shaped thin piezoelectric body. The vibrating body 22 is formed of, for example, a piezoelectric ceramic or the like, and is subjected to polarization processing in the thickness direction. As vibrating means for vibrating the vibrating body 22, electrodes 24 and 26 facing each other are formed on the entire inner surface and outer surface of the vibrating body 22, respectively. In this case, the electrodes 24 and 26 are formed on the vibrating body 22 by a method such as plating, vapor deposition, or sputtering using a conductive material such as gold or nickel. The edge of the sounding body 20 is firmly adhered to the upper surface of the cushioning material 16 by the adhesive 28.
[0012]
Leads and terminals (not shown) are connected to the electrodes 24 and 26 to apply signals to the electrodes 24 and 26. A groove or the like connecting the inside and outside of the sounding body 20 may be formed in the base member 12 in order to draw out a lead wire, a terminal, or the like connected to the electrode 26 on the inner surface of the sounding body 20.
[0013]
In this speaker 10, sound is radiated from the curved outer surface of the sounding body 20 by inputting signals to the electrodes 24 and 26, thereby causing the whole of the vibrating body 22 to undergo respiratory vibration that expands and contracts. . However, the sound wave radiated from the inner surface of the sounding body 20 is not radiated to the outside due to the presence of the base member 12. Note that a backload or the like may be formed on the base member 12 in order to use sound waves radiated from the inner surface of the sounding body 20.
[0014]
In the speaker 10, the difference in thermal expansion coefficient between the base member 12 and the sounding body 20 is absorbed by the cushioning material 16 disposed between the base member 12 and the sounding body 20. That is, it is possible to prevent the displacement of the base member 12 due to the temperature change from being absorbed by the cushioning material 16 and to prevent the sounding body 20 from breaking. As described above, the displacement limit of the base member 12 due to heat is improved, and durability against a thermal shock test or the like can be improved. Further, as the material of the base member 12, it is not necessary to adopt a material having a thermal expansion coefficient close to that of the sounding body 20, and the material can be freely selected. Therefore, the base member 12 is not limited to conventional aluminum or the like, and can be formed of a synthetic resin or the like. Further, the material of the base member 12 can be adopted according to the material characteristics such as hardness, and the speaker characteristics can be selected based on such material characteristics. Thus, the choice of the design of the speaker 10 can be increased by the material of the base member 12.
[0015]
Further, the cushioning material 16 also functions as a damping material, and prevents vibration leakage from the edge of the sounding body 20. Furthermore, since the cushioning member 16 has a stable shape and characteristics, the speaker 10 with small characteristic variations can be obtained. That is, by using the cushioning material 16 having an appropriate cushioning property, the speaker characteristics can be stabilized.
[0016]
As described above, the cushioning member 16 can absorb the difference in the coefficient of thermal expansion between the base member 12 and the sounding body 20, and can adjust the flexibility and cushioning property. One having a large fixing strength can be selected. Therefore, it is not necessary to consider the flexibility and cushioning property of the adhesives 18 and 28, and it is possible to widen the selection range of the adhesives.
[0017]
The speaker 10 can absorb the difference in the coefficient of thermal expansion between the base member 12 and the sounding body 20, so that there is no problem that the sounding body 20 is broken, and the speaker 10 can be highly reliable. In addition, by using the cushioning material 16 having stable characteristics, stable speaker characteristics can be obtained. Furthermore, since the range of selection of the material of each part can be widened, the cost can be reduced and a material having desired characteristics can be selected.
[0018]
【Example】
PBT (polybutylene terephthalate) (elastic modulus 2900 MPa) and ABS (acrylonitrile butadiene styrene copolymer) (elastic modulus 2500 MPa) were used to form a base member having the same dimensions and the same shape. The speaker was formed by directly bonding the sounding body to these base members with an adhesive. The relationship between the frequency and the sound pressure level of the obtained speaker was measured, and the measurement result is shown in FIG.
[0019]
Further, a speaker was formed by supporting a sounding body with a buffer member made of silicon rubber (hardness HS70) sandwiched between base members made of the above-described materials. The base member and the cushioning material were adhered with an adhesive, and the cushioning material and the edge of the sounding body were also adhered with the adhesive. The relationship between the frequency and the sound pressure level of the obtained speaker was measured, and the result is shown in FIG.
[0020]
As can be seen from FIG. 4, when the sounding body is directly bonded to the base member with an adhesive, a difference of 5 dB or more in sound pressure characteristics is observed depending on the material of the base member. In contrast, as can be seen from FIG. 5, when the sounding body is supported on the base member with the cushioning material interposed therebetween, the characteristics are uniform, and it can be determined that there is no advantage difference due to the difference in the material of the base member. .
[0021]
According to the present invention, the hemispherical sounding body is supported on the base member with the cushioning material interposed therebetween, so that the selection range of the material of each component can be widened and the cost can be reduced. Materials having desired characteristics can be used. Further, it is possible to prevent the sounding body from being damaged due to a difference in thermal expansion coefficient between the base member and the sounding body. Further, since the characteristics of the cushioning material for supporting the sound generating member are stable, a speaker having stable speaker characteristics can be obtained.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an example of a speaker of the present invention.
FIG. 2 is an illustrative sectional view of the speaker shown in FIG. 1;
FIG. 3 is an illustrative sectional view showing a support portion between a base member and a sounding body.
FIG. 4 is a graph showing sound pressure characteristics when a sound-generating member is supported on a base member with an adhesive.
FIG. 5 is a graph showing sound pressure characteristics when a sound-generating member is supported on a base member with a cushioning material interposed therebetween.
FIG. 6 is an illustrative sectional view showing an example of a conventional speaker.
[Explanation of symbols]
Reference Signs List 10 speaker 12 base member 14 concave portion 16 cushioning material 18 adhesive 20 sounding body 22 vibrating body 24, 26 electrode 28 adhesive

Claims (2)

Supports a sounding body composed of a vibrating body formed of a thin piezoelectric body formed in a dome shape, and electrodes formed at opposing positions on an outer surface and an inner surface of the vibrating body, and supports an edge of the sounding body. Speaker including a base member for
A speaker, wherein a cushioning material is disposed between an edge of the sounding body and the base member. 2. The speaker according to claim 1, wherein one surface of the cushioning material and the base member are fixed with an adhesive, and the other surface of the cushioning material and an edge of the sounding body are fixed with an adhesive.

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