JPH0520956B2 - - Google Patents
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- Publication number
- JPH0520956B2 JPH0520956B2 JP3430688A JP3430688A JPH0520956B2 JP H0520956 B2 JPH0520956 B2 JP H0520956B2 JP 3430688 A JP3430688 A JP 3430688A JP 3430688 A JP3430688 A JP 3430688A JP H0520956 B2 JPH0520956 B2 JP H0520956B2
- Authority
- JP
- Japan
- Prior art keywords
- piezoelectric
- diaphragm
- resonance frequency
- frequency
- diameter
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 239000002184 metal Substances 0.000 claims description 34
- 230000035945 sensitivity Effects 0.000 description 25
- 239000000919 ceramic Substances 0.000 description 9
- 230000000052 comparative effect Effects 0.000 description 6
- 238000005452 bending Methods 0.000 description 4
- WABPQHHGFIMREM-UHFFFAOYSA-N lead(0) Chemical compound [Pb] WABPQHHGFIMREM-UHFFFAOYSA-N 0.000 description 4
- 239000000463 material Substances 0.000 description 3
- 238000013016 damping Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000006073 displacement reaction Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 229910001369 Brass Inorganic materials 0.000 description 1
- 239000010951 brass Substances 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 230000002093 peripheral effect Effects 0.000 description 1
Description
【発明の詳細な説明】
[産業上の利用分野]
本発明は、両主面に電極を有する圧電板を金属
振動板に貼り合せた構成の圧電振動板を含む圧電
型受話器に関するものである。DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a piezoelectric receiver including a piezoelectric diaphragm having a structure in which a piezoelectric plate having electrodes on both principal surfaces is bonded to a metal diaphragm.
[従来の技術]
セラミツク圧電板の両主面に電極を有するセラ
ミツク圧電板を金属振動板に貼り付けた構造の圧
電振動子を備えた圧電型受話器は公知である。ま
た、圧電振動子の前面に放音孔を有する気室を設
け、後面に音響漏洩孔を有する気室を設けて自由
度3の構造になし、再生周波数帯域全体の高感度
化を図り、且つ再生帯域の上限を広げ、且つ周波
数特性を平坦化することも公知である。[Prior Art] A piezoelectric receiver equipped with a piezoelectric vibrator having a structure in which a ceramic piezoelectric plate having electrodes on both main surfaces thereof is attached to a metal diaphragm is known. In addition, an air chamber with a sound emission hole is provided on the front surface of the piezoelectric vibrator, and an air chamber with an acoustic leakage hole is provided on the rear surface to create a structure with three degrees of freedom, achieving high sensitivity in the entire reproduction frequency band. It is also known to widen the upper limit of the reproduction band and flatten the frequency characteristics.
[発明が解決しようとする課題]
しかし、従来の圧電型受話器の帯域上限は、こ
れに用いる圧電振動板の基本共振周波数の約3倍
の周波数に限定されてしまうため、必要な再生帯
域を得るには、基本共振周波数をむやみに下げら
れず、基本共振周波数を下げることによつて高感
度化、高音質化を図るためへの大きな妨げとなつ
ていた。[Problem to be solved by the invention] However, the upper limit of the band of the conventional piezoelectric handset is limited to a frequency that is approximately three times the fundamental resonance frequency of the piezoelectric diaphragm used in the receiver, so it is difficult to obtain the necessary reproduction band. In this case, the fundamental resonant frequency cannot be lowered unnecessarily, and this has been a major hindrance to achieving higher sensitivity and higher sound quality by lowering the fundamental resonant frequency.
そこで、本発明の目的は、高感度及び/又は広
帯域の圧電型受話器を提供することにある。 SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a piezoelectric handset with high sensitivity and/or wideband.
[課題を解決するための手段]
上記目的を達成するための本発明は、一方の主
面に第1の電極を有し、他方の主面に第2の電極
を有する圧電板が金属振動板に貼り付けられて成
る圧電振動板と、前記金属振動板の端縁を支持し
且つ前記圧電振動板の前面に放音孔を有する気室
が得られ、前記圧電振動板の後面にも気室が得ら
れるように形成された容器とを備えた圧電型受話
器において、前記圧電振動板の1次共振周波数の
約4倍の2次共振周波数の音圧が1次共振周波数
より十分低い周波数の音圧に対して−6dBよりも
高くなるような圧電振動板を用い、自由度3以上
の構成の圧電型受話器の1次共振周波数の約3倍
で決定される周波数帯域の上限に1次共振周波数
の約4倍の2次共振音圧を付加し、帯域上限を1
次共振周波数の約4倍まで拡張したことを特徴と
する圧電型受話器に係わるものである。即ち、あ
らかじめ2次共振音圧が高くなるように圧電振動
板の、例えば圧電セラミツク板と金属振動板との
直径比を選定し、これによつて得られた2次共振
音圧を圧電型受話器の周波数帯域上限に付加する
ことによつて、低共振化による高感度化、又は広
帯域化をはかることを特徴とする圧電型受話器に
係わるものである。[Means for Solving the Problems] The present invention for achieving the above object is characterized in that a piezoelectric plate having a first electrode on one main surface and a second electrode on the other main surface is a metal diaphragm. A piezoelectric diaphragm is attached to the piezoelectric diaphragm, and an air chamber is obtained that supports the edge of the metal diaphragm and has sound emission holes on the front surface of the piezoelectric diaphragm, and an air chamber is also provided on the rear surface of the piezoelectric diaphragm. In the piezoelectric receiver, the sound pressure of the piezoelectric diaphragm has a secondary resonance frequency that is approximately four times the primary resonance frequency of the piezoelectric diaphragm, and a sound pressure of a frequency sufficiently lower than the primary resonance frequency. Using a piezoelectric diaphragm that is higher than -6 dB with respect to pressure, the primary resonant frequency is set at the upper limit of the frequency band determined by approximately three times the primary resonant frequency of a piezoelectric receiver configured with three or more degrees of freedom. Adds a secondary resonance sound pressure approximately 4 times that of the
This invention relates to a piezoelectric receiver characterized by extending the next resonance frequency to about four times as high. That is, the diameter ratio of the piezoelectric diaphragm, for example, the piezoelectric ceramic plate and the metal diaphragm, is selected in advance so that the secondary resonance sound pressure is high, and the secondary resonance sound pressure obtained thereby is applied to the piezoelectric receiver. This relates to a piezoelectric receiver that is characterized by increasing sensitivity or widening the band by reducing resonance by adding the above frequency band to the upper limit of the frequency band.
[作用]
従来の圧電型受話器においては、圧電振動板の
高次共振は通話品質の低下に結びつくとの考え
で、高次共振レベルを抑圧することが重要であつ
た。これに対して、本発明では第2次共振を積極
的に利用している。即ち、第2次共振周波数近傍
音圧を再生帯域上限に付加できれば、必然的に第
1次共振周波数を低くすることができる。第1次
共振周波数を低くするために、面積比S1/S2を
変えずに例えば圧電板及び金属振動板の面積を大
きくすれば感度が高くなる。これにより、帯域を
縮小することなく高感度、高品質の圧電型受話器
が得られる。[Function] In conventional piezoelectric handsets, it has been important to suppress the high-order resonance level, because it is thought that the high-order resonance of the piezoelectric diaphragm leads to a deterioration in speech quality. In contrast, the present invention actively utilizes the second-order resonance. That is, if the sound pressure near the second-order resonance frequency can be added to the upper limit of the reproduction band, the first-order resonance frequency can inevitably be lowered. In order to lower the first resonance frequency, sensitivity can be increased by increasing the areas of the piezoelectric plate and metal diaphragm, for example, without changing the area ratio S1/S2. As a result, a piezoelectric handset with high sensitivity and high quality can be obtained without reducing the band.
第1次及び第2次共振周波数を下げないように
構成した場合には、第1次共振周波数までの帯域
での感度の向上は少ないが、第2次共振周波数及
びこの近傍の感度が上るため、従来利用されてい
なかつた第2次共振周波数及びこの近傍を再生帯
域として利用することが可能になり、広帯域化が
達成される。 If the configuration is configured so that the primary and secondary resonance frequencies are not lowered, there will be little improvement in sensitivity in the band up to the primary resonance frequency, but the sensitivity at and around the secondary resonance frequency will increase. , it becomes possible to use the second-order resonance frequency, which has not been used in the past, and its vicinity as a reproduction band, and a wide band can be achieved.
[実施例]
次に、第1図〜第6図を参照して本発明の実施
例に係わる電話の圧電型受話器を説明する。[Embodiment] Next, a piezoelectric telephone receiver according to an embodiment of the present invention will be described with reference to FIGS. 1 to 6.
圧電型受話器は、第1図及び第2図に示す如
く、圧電振動板1を容器2に装着することによつ
て構成されている。圧電振動板1は、円板状のセ
ラミツク圧電板3とこれが貼り付けられている円
板状の金属振動板4とから成る。第1図では図示
の都合上省略されているが、セラミツク圧電板3
は、第3図に拡大図示する如く、一方の主面3a
のほぼ全部に円形の第1の金属電極5を有し、他
方の主面3bのほぼ全部に円形の第2の金属電極
6を有し、第2の金属電極6が接着剤7によつて
金属振動板4に貼り付けられている。 The piezoelectric receiver is constructed by attaching a piezoelectric diaphragm 1 to a container 2, as shown in FIGS. 1 and 2. The piezoelectric diaphragm 1 consists of a disk-shaped ceramic piezoelectric plate 3 and a disk-shaped metal diaphragm 4 to which it is attached. Although omitted in FIG. 1 for convenience of illustration, the ceramic piezoelectric plate 3
As shown in an enlarged view in FIG. 3, one main surface 3a
It has a circular first metal electrode 5 on almost the entire surface of the other main surface 3b, and has a circular second metal electrode 6 on almost the entire surface of the other main surface 3b. It is attached to the metal diaphragm 4.
黄銅円板からなる金属振動板4の周縁部は容器
2に固定されている。圧電振動板1の支持手段及
び気室形成手段としての容器2は、圧電振動板1
の前面に放音孔8を有する第1の気室9が得ら
れ、後面に音響漏洩孔10を有する第2の気室1
1が得られるように形成されている。なお、音響
漏洩孔10は制動材10aで塞がれている。 The peripheral edge of a metal diaphragm 4 made of a brass disc is fixed to the container 2. A container 2 serving as a support means for the piezoelectric diaphragm 1 and an air chamber forming means is used to support the piezoelectric diaphragm 1.
A first air chamber 9 having a sound emission hole 8 on the front side is obtained, and a second air chamber 1 having an acoustic leakage hole 10 on the rear side is obtained.
1. Note that the acoustic leak hole 10 is closed with a damping material 10a.
上述のように圧電型受話器を自由度3に構成す
れば、周波数特性の平坦化、再生帯域の上限を伸
ばすことによる広帯域化、及び再生帯域全体の高
感度化が達成される。なお、従来の圧電型受話器
も自由度3に構成されているが、単に自由度3に
しても再生帯域の上限は圧電振動板1の基本共振
周波数の約3倍である。 By configuring the piezoelectric receiver to have three degrees of freedom as described above, it is possible to flatten the frequency characteristics, widen the reproduction band by extending the upper limit of the reproduction band, and increase the sensitivity of the entire reproduction band. Note that the conventional piezoelectric receiver is also configured with three degrees of freedom, but even if the degree of freedom is simply three, the upper limit of the reproduction band is about three times the fundamental resonance frequency of the piezoelectric diaphragm 1.
セラミツク圧電板3の第1の金属電極5には第
1の伸縮自在リード線12が接続され、金属振動
板4には第2の伸縮自在リード線13が接続され
ている。 A first elastic lead wire 12 is connected to the first metal electrode 5 of the ceramic piezoelectric plate 3, and a second elastic lead wire 13 is connected to the metal diaphragm 4.
ここで、具体的に2次共振音圧を上る方法は例
えば圧電セラミツク板3の直径D1と金属振動板
非固定領域の直径(有効径)D2のを比を変える
ことが考えられる。圧電振動板3の直径D1と金
属振動板4の直径(有効径)D2との比D1/D2の
変化による振動姿態の変化を第6図参照して説明
する。第1次共振周波数以下での圧電振動板1の
屈曲運動は第6図Aで点線で示すように生じ、第
2次共振周波数又はこの近傍での圧電振動板1の
屈曲運動は第6図Bで点線で示すように生じる。
第2次共振周波数又はこの近傍では、屈曲運動の
節部14が第6図B及び第2図に示す如く圧電板
3を同心円状に囲むような位置に生じ、このとき
音圧は、第6図Bの節部14よりも内側の点線1
5aで示す部分で生じる体積排除量と節部14よ
りも外側の点線15b,15cで示す部分で生じ
る体積排除量との差分で決まる。また、この節部
14の位置は、セラミツク圧電板の直径により移
動し第6図Cのようにセラミツク圧電板の直径を
大きくすると節部14は周辺部近くなり、2次共
振音圧は下り、逆の場合は音圧は上る。 Here, a concrete method for increasing the secondary resonance sound pressure may be, for example, changing the ratio of the diameter D1 of the piezoelectric ceramic plate 3 to the diameter (effective diameter) D2 of the area where the metal diaphragm is not fixed. A change in the vibration state due to a change in the ratio D1/D2 between the diameter D1 of the piezoelectric diaphragm 3 and the diameter (effective diameter) D2 of the metal diaphragm 4 will be explained with reference to FIG. The bending motion of the piezoelectric diaphragm 1 below the first resonance frequency occurs as shown by the dotted line in FIG. 6A, and the bending motion of the piezoelectric diaphragm 1 at or near the second resonance frequency occurs as shown in FIG. 6B. occurs as shown by the dotted line.
At or near the second resonance frequency, the nodes 14 of the bending motion occur at positions concentrically surrounding the piezoelectric plate 3 as shown in FIG. 6B and FIG. Dotted line 1 inside the node 14 in Figure B
It is determined by the difference between the amount of volume displacement that occurs at the portion indicated by 5a and the amount of volume displacement that occurs at the portions outside of the joint portion 14 and indicated by dotted lines 15b and 15c. Furthermore, the position of this node 14 changes depending on the diameter of the ceramic piezoelectric plate, and as shown in FIG. In this case, the sound pressure increases.
本発明に従つて再生帯域中に第2次共振周波数
を含めるために、金属振動板4の直径(有効径)
D2が33mmに設定され、圧電板3の直径D1が25mm
に設定されている。なお、圧電板3及び金属振動
板4の厚みは共に0.1mmであり、第1次共振周波
数は従来よりも大幅に低い約900Hzである。本発
明に用いる振動板は第1次及び第2次共振周波数
を下げるために圧電板3及び金属振動板4の直径
及び面積は従来の圧電振動板に比べて大きいが、
両直径の比D1/D2は25/33であつて従来よりも
小さい。 In order to include the second resonance frequency in the reproduction band according to the present invention, the diameter (effective diameter) of the metal diaphragm 4 is
D2 is set to 33mm, and the diameter D1 of piezoelectric plate 3 is 25mm.
is set to . Note that the thickness of the piezoelectric plate 3 and the metal diaphragm 4 are both 0.1 mm, and the primary resonance frequency is approximately 900 Hz, which is significantly lower than that of the conventional one. In the diaphragm used in the present invention, the diameter and area of the piezoelectric plate 3 and metal diaphragm 4 are larger than those of conventional piezoelectric diaphragms in order to lower the first and second resonance frequencies.
The ratio D1/D2 of both diameters is 25/33, which is smaller than the conventional one.
圧電振動板1を上述の如く構成すれば、圧電振
動板1のみ感度周波数特性は第4図のaになり、
900Hzに第1次共振P1が得られると共に約3600Hz
の点に比較的高レベルの第2次共振P2が得られ
る。本実施例に従う圧電振動板を使用して第1図
に示すように自由度3の圧電型受話器を構成すれ
ば、第5図のcで示す感度周波数特性になり、周
波数特性の平坦化、広帯域化、高感度化が達成さ
れる。従つて、第2次共振周波数及びこの近傍ま
でを再生帯域として利用することができ、且つ低
域及び高域の感度が従来よりも高くなる。 If the piezoelectric diaphragm 1 is configured as described above, the sensitivity frequency characteristic of the piezoelectric diaphragm 1 alone will be as shown in a of FIG. 4,
The first resonance P1 is obtained at 900Hz and approximately 3600Hz
A relatively high level of second-order resonance P2 is obtained at the point. If a piezoelectric handset with three degrees of freedom is constructed using the piezoelectric diaphragm according to this embodiment as shown in FIG. 1, the sensitivity frequency characteristic will be as shown in c in FIG. and high sensitivity are achieved. Therefore, the second resonant frequency and its vicinity can be used as a reproduction band, and the sensitivity in the low and high frequencies becomes higher than before.
比較のために、圧電板3の直径D1が28mm、金
属振動板4の直径(有効径)D2を33mm、厚さは
共に0.1mmの圧電振動板を本発明に従う実施例の
ものと同様に作製し、この感度を求めたところ、
第4図のbに示す感度周波数特性が得られ、これ
を第1図と同様に容器2で支持して自由度3の構
造にしたところ、感度周波数特性は第5図のdと
なつた。この比較例の場合には、金属振動板の直
径を本発明の実施例と同様に比較的大きい33mmに
したので、第1次共振周波数までの低域における
感度は、本発明の実施例とさほど差がない。しか
し、第2次共振周波数及びこの近傍の感度が極め
て低く、単峰特性に近いので、圧電型受話器を構
成した場合、第5図の特性線dに示すように約
3kHz以上の領域の感度が実施例の特性線cに比
べて低くなる。 For comparison, a piezoelectric diaphragm in which the diameter D1 of the piezoelectric plate 3 is 28 mm, the diameter (effective diameter) D2 of the metal diaphragm 4 is 33 mm, and the thickness of both is 0.1 mm was fabricated in the same manner as in the example according to the present invention. When I calculated this sensitivity, I found that
The sensitivity frequency characteristic shown in FIG. 4b was obtained, and when this was supported by the container 2 in the same manner as in FIG. 1 to create a structure with three degrees of freedom, the sensitivity frequency characteristic became as shown in FIG. 5 d. In the case of this comparative example, the diameter of the metal diaphragm was set to a relatively large 33 mm, similar to the example of the present invention, so the sensitivity in the low range up to the first resonance frequency was not as great as that of the example of the present invention. There is no difference. However, the sensitivity at and around the second resonance frequency is extremely low and has almost a single peak characteristic, so when a piezoelectric receiver is configured, the
The sensitivity in the region of 3 kHz or higher is lower than that of the characteristic line c of the example.
本発明に従つて圧電板3の直径D1と金属振動
板4の直径D2との比D1/D2を小さくした場合に
は、上記の差分が大きくなり、音圧レベルが高く
なる。 When the ratio D1/D2 between the diameter D1 of the piezoelectric plate 3 and the diameter D2 of the metal diaphragm 4 is reduced according to the present invention, the above-mentioned difference becomes large and the sound pressure level becomes high.
一方、比較例のように圧電板3の直径D1と金
属振動板4の直径D2との比D1/D2を大きくした
場合には、第2次共振周波数及びこの近傍で第6
図cに示す如く節部14が圧電振動板1の中心寄
りになり、点線15aで示す部分の体積排除量と
点線15b,15cで示す部分の体積排除量との
差分が少なくなり、出力音圧が低下する。従つ
て、比較例の場合は第2次共振周波数及びこの近
傍を再生帯域として有効に利用することができな
い。 On the other hand, when the ratio D1/D2 of the diameter D1 of the piezoelectric plate 3 and the diameter D2 of the metal diaphragm 4 is increased as in the comparative example, the second resonance frequency and the sixth
As shown in FIG. decreases. Therefore, in the case of the comparative example, the second-order resonance frequency and its vicinity cannot be effectively used as a reproduction band.
比較例においては、金属振動板4の直径を実施
例に合せて比較的大きく設定したので、低域にお
ける感度が比較的高くなつているが、従来の第1
次共振周波数を1200Hz程度に設定して広帯域化を
図る場合には、必然的に金属振動板4の直径を小
さくすることが要求され、低域における感度も本
発明の実施例よりも悪くなり、周波数特性は第5
図のeになる。 In the comparative example, the diameter of the metal diaphragm 4 was set relatively large according to the example, so the sensitivity in the low range was relatively high.
When setting the next resonance frequency to about 1200 Hz to widen the band, it is necessary to reduce the diameter of the metal diaphragm 4, and the sensitivity in the low range becomes worse than the embodiment of the present invention. The frequency characteristic is the fifth
It becomes e in the figure.
上述の如く、本発明の実施例によれば、第1次
共振周波数を下げることによつて高感度化が可能
になり、且つ第2次共振周波数及びこの近傍も再
生帯域として利用することが可能であるので高域
を低下させることがない。この結果、高感度、高
品質の圧電型受話器を提供することができる。 As described above, according to the embodiment of the present invention, it is possible to increase the sensitivity by lowering the first resonant frequency, and it is also possible to use the second resonant frequency and its vicinity as a reproduction band. Therefore, there is no reduction in high frequencies. As a result, a piezoelectric handset with high sensitivity and high quality can be provided.
[変形例]
本発明は上述の実施例に限定されるものでな
く、例えば次の変形が可能なものである。[Modifications] The present invention is not limited to the above-described embodiments, and, for example, the following modifications are possible.
(1) 第1図の放音孔8を1個にしてもよい。ま
た、この複数個の放音孔8の一部を制動材(ダ
ンパー材)で塞いで、周波数特性の平坦化を図
つてもよい。(1) The number of sound emitting holes 8 in FIG. 1 may be reduced to one. Further, a portion of the plurality of sound emitting holes 8 may be closed with a damping material (damper material) to flatten the frequency characteristics.
(2) 金属振動板4に対するリード線13の電気的
接続を固定端又はこの近傍で行う場合には伸縮
自在のリード線を使用しなくてもよい。(2) When electrically connecting the lead wire 13 to the metal diaphragm 4 at the fixed end or in the vicinity thereof, it is not necessary to use a telescopic lead wire.
(3) 圧電セラミツク板3及び金属振動板4の寸
法、形状等を種々変えることができる。但し、
第2次共振周波数及びこの近傍を再生帯域に含
めるために、2次共振音圧は圧電振動板の1次
共振周波数より十分に低周波数の音圧に対して
−6dB以上高くなるように圧電板3の直径D1
と金属振動板4の直径D2との比D1/D2等を設
定することが望ましい。(3) The dimensions, shapes, etc. of the piezoelectric ceramic plate 3 and the metal diaphragm 4 can be changed in various ways. however,
In order to include the secondary resonance frequency and its vicinity in the reproduction band, the piezoelectric diaphragm is designed so that the secondary resonance sound pressure is -6 dB or more higher than the sound pressure at frequencies sufficiently lower than the primary resonance frequency of the piezoelectric diaphragm. 3 diameter D1
It is desirable to set a ratio D1/D2 between the diameter D2 of the metal diaphragm 4 and the diameter D2 of the metal diaphragm 4.
(4) 第1次共振周波数を約1000Hz以下に設定する
場合に本発明の作用効果が顕著に得られるが、
この様に特に低く設定しない構造とすることも
できる。この場合であつても、圧電板3の直径
D1と金属振動板4の直径D2との比D1/D2を
小さくすると、第2次共振周波数及この近傍で
の屈曲運動の節部14が第6図Bに示す如く金
属振動板4の周縁に近づくので、高い音圧レベ
ルを得ることができる。この結果、第1次共振
周波数の約4倍程度の第2次共振周波数及びこ
の近傍も再生帯域に含めることができ、広帯域
化が達成される。(4) The effects of the present invention are significantly obtained when the primary resonance frequency is set to approximately 1000Hz or less;
In this way, it is also possible to have a structure in which it is not set particularly low. Even in this case, the diameter of the piezoelectric plate 3
When the ratio D1/D2 between D1 and the diameter D2 of the metal diaphragm 4 is decreased, the second resonance frequency and the node 14 of the bending motion in the vicinity thereof are shifted to the periphery of the metal diaphragm 4 as shown in FIG. 6B. Because they are close to each other, a high sound pressure level can be obtained. As a result, the second resonant frequency, which is about four times the first resonant frequency, and its vicinity can also be included in the reproduction band, and a wide band can be achieved.
[発明の効果]
以上説明したように、第2次共振周波数及びこ
の近傍も再生帯域として利用することによつて高
感度化及び/又は広帯域化が可能となる。[Effects of the Invention] As explained above, by using the second-order resonance frequency and its vicinity as a reproduction band, it is possible to achieve higher sensitivity and/or a wider band.
第1図は本発明の一実施例に係わる圧電型受話
器を原理的に示す断面図、第2図はリード線を除
いて示す第1図の−線断面図、第3図は圧電
振動板の一部を示す第2図の−線に相当する
部分の拡大断面図、第4図は実施例、及び比較例
の圧電振動板の感度周波数特性図、第5図は実施
例及び比較例の圧電型受話器の感度周波数特性
図、第6図は実施例の圧電振動板の第1次及び第
2次共振周波数における振動姿態を原理的に示す
図、第7図は比較例の第2次共振周波数における
振動姿態を原理的に示す図である。
1……圧電振動板、2……容器、3……セラミ
ツク圧電板、4……金属振動板、5……第1の金
属電極、6……第2の金属電極。
FIG. 1 is a cross-sectional view showing the principle of a piezoelectric receiver according to an embodiment of the present invention, FIG. 2 is a cross-sectional view taken along the line -- in FIG. 1 with the lead wires removed, and FIG. FIG. 4 is a sensitivity frequency characteristic diagram of the piezoelectric diaphragms of the example and comparative example, and FIG. Fig. 6 is a diagram showing the vibration mode of the piezoelectric diaphragm of the example at the primary and secondary resonance frequencies, and Fig. 7 is the secondary resonance frequency of the comparative example. FIG. DESCRIPTION OF SYMBOLS 1... Piezoelectric diaphragm, 2... Container, 3... Ceramic piezoelectric plate, 4... Metal diaphragm, 5... First metal electrode, 6... Second metal electrode.
Claims (1)
に第2の電極を有する圧電板が金属振動板に貼り
付けられて成る圧電振動板と、 前記金属振動板の端縁を支持し且つ前記圧電振
動板の前面に放音孔を有する気室が得られ、前記
圧電振動板の後面にも気室が得られるように形成
された容器と を備えた自由度3以上の構成の圧電型受話器にお
いて、 前記圧電振動板の1次共振周波数の約4倍の2
次共振周波数の音圧が1次共振周波数より十分低
い周波数の音圧に対して−6dBよりも高くなるよ
うな圧電振動板を用い、自由度3以上の構成の圧
電型受話器の1次共振周波数の約3倍で決定され
る周波数帯域の上限に1次共振周波数の約4倍の
2次共振音圧を付加し、帯域上限を1次共振周波
数の約4倍まで拡張したことを特徴とする圧電型
受話器。[Scope of Claims] 1. A piezoelectric diaphragm comprising a piezoelectric plate having a first electrode on one main surface and a second electrode on the other main surface attached to a metal diaphragm; and a container formed to support an edge of the diaphragm and to provide an air chamber having a sound emission hole on the front surface of the piezoelectric diaphragm, and to provide an air chamber on the rear surface of the piezoelectric diaphragm. In a piezoelectric receiver configured with three or more degrees of freedom, 2 times the primary resonance frequency of the piezoelectric diaphragm, which is approximately four times the primary resonance frequency of the piezoelectric diaphragm.
The primary resonance frequency of a piezoelectric receiver configured with three or more degrees of freedom, using a piezoelectric diaphragm in which the sound pressure at the next resonance frequency is higher than -6 dB with respect to the sound pressure at a frequency sufficiently lower than the first resonance frequency. A secondary resonance sound pressure of approximately 4 times the primary resonance frequency is added to the upper limit of the frequency band determined by approximately 3 times the primary resonance frequency, thereby extending the band upper limit to approximately 4 times the primary resonance frequency. Piezoelectric receiver.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP3430688A JPH01209899A (en) | 1988-02-17 | 1988-02-17 | Piezoelectric telephone receiver |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP3430688A JPH01209899A (en) | 1988-02-17 | 1988-02-17 | Piezoelectric telephone receiver |
Publications (2)
Publication Number | Publication Date |
---|---|
JPH01209899A JPH01209899A (en) | 1989-08-23 |
JPH0520956B2 true JPH0520956B2 (en) | 1993-03-22 |
Family
ID=12410475
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP3430688A Granted JPH01209899A (en) | 1988-02-17 | 1988-02-17 | Piezoelectric telephone receiver |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPH01209899A (en) |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP5222217B2 (en) * | 2009-04-24 | 2013-06-26 | パナソニック株式会社 | smoke detector |
-
1988
- 1988-02-17 JP JP3430688A patent/JPH01209899A/en active Granted
Also Published As
Publication number | Publication date |
---|---|
JPH01209899A (en) | 1989-08-23 |
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