壓電陶瓷揚(yáng)聲器及受話器介紹

一、壓電陶瓷揚(yáng)聲器Piezoelectric ceramic speaker

圖2.12所示,是一種改善了中、低頻特性壓電陶瓷揚(yáng)聲器。它是由三個壓電陶瓷振子5和一個壓電陶瓷振子6所組成。壓電陶瓷振子5的直徑為21毫米，6的直徑為27毫米，3為壓電陶瓷片，4為振動板，直徑為50毫米。1為紙質(zhì)圓錐形振動板4的邊緣部分與有底框2的開口邊緣連接。

   這種結(jié)構(gòu)的揚(yáng)聲器，音頻訊號將同時加在第一和第二層壓電陶瓷振子5和6上，因此各振動片都是同相位的彎曲振動，從而驅(qū)動振板4將獲得較大的振幅，如圖2.12(b)所示的虛線和實線的距離。

Fig.2.12. It is one kind Piezoelectric ceramic speaker of improvement middle and low frequency.It is composed of three piezoelectric ceramic vibrators 5 and a piezoelectric ceramic vibrator 6. The piezoelectric ceramic vibrator 5 of diameter is 21 mm, the diameter of 6 is 27 mm, 3- the piezoelectric ceramic disk , 4-the vibration disk, and the diameter is 50 mm. 1 is the paper cone vibration plate edge portions of 4 and a frame of 2 connected with an opening edge.

The structure of speaker, the audio signal input the first and second piezoelectric ceramic vibrators o 5 and 6 at the same time, so that the bending vibration is the same of phase, It will drive vibration plate 4 to produce a larger amplitude, as shown in Fig.2.12 (b) the distance of the dashed and solid lines.

 圖2.12 改進(jìn)型壓電陶瓷揚(yáng)聲器

圖2.13為此種壓電陶瓷揚(yáng)聲器的頻響特性，虛線是單一結(jié)構(gòu)的壓電陶瓷揚(yáng)聲器的特性曲線。

由圖可見，這種壓電陶瓷揚(yáng)聲器在100-5000Hz頻率范圍內(nèi)，有足夠的放音聲壓，低頻部分的聲壓特別明顯。

Fig.2.13 shown the frequency response characteristics for this kind of piezoelectric ceramic speaker; Dash line is the piezoelectric ceramic loudspeaker characteristic curve for the single structure.

Seen by the graph, the frequency range of piezoelectric ceramic speaker within the scope of 100-5000Hz, there is the enough sound pressure level of sound reproduction, the sound pressure level is Special obvious in the low-frequency range.

二、壓電陶瓷受話器Piezoelectric ceramic receiver

壓電陶瓷受話器具有重量輕、不怕電磁干攏等特點而受到重視，由于此受話器具有良好的防潮性能，主要使用在輕潛水通訊設(shè)備中。  由圖2.19可見，它是由三個自由度音響振動系列構(gòu)成。振動板1由壓電陶瓷片和薄金屬片用導(dǎo)電膠粘結(jié)而成，經(jīng)由框架2固定于內(nèi)框上。于是將受話器腔體分為：第一前氣腔5與第一后氣腔6，第二前氣腔7（耳機(jī)）通過傳聲孔3與第一前氣腔5相通，第一后氣腔6由阻尼孔與外空間相連。當(dāng)交流信號由引線端8輸入時，振動板便隨外加信號產(chǎn)生伸縮振動，其所產(chǎn)生的聲壓，由第二前氣腔7引出，即可聽到聲音。

其頻響特性如圖2.20所示，圖中實線是沒有泄露時的特性，點劃線是聽筒緊貼耳朵壓力為700g時的特性，虛線是200g的特性。

  It has received attention because the advantage of piezoelectric ceramic receiver there is light weight, no electromagnetic interference (EMI) characteristics etc, the product has good moisture resistance, used in lightweight diving communication equipment mainly. Fig.2.19, it is composed of three degrees of freedom sound vibration. 1- the vibration plate, its edge on the inner frame 2: the edge of metal is fixed and bonded by electric conduction paste between the piezoelectric ceramic disk and the thin metal disk. Then the receiver chamber is divided into: 5-the first front air chamber and 6-the first behind air chamber, 7-the second front the air chamber( headphones ) and the first front air chamber 5 connected by 3-the sound hole, the first behind air chamber and the outside space connected by damping hole. When the AC signal input through 8- the terminal wire, the vibration will generate the stretching vibration with an external signal, the generating sound pressure level was leaded through the second front air chamber, So we can hear the sound.

The frequency response characteristics as shown in Fig.2.20, the solid line is no reveal, the point line is close to the ear, the pressure is 700g, the dotted line is close to the ear, the pressure is 200g.