| 摘要 |
PROBLEM TO BE SOLVED: To provide a speaker which can be miniaturized, improves the sound quality in the low frequency band and can improve sound pressure by partially holding the periphery of the diaphragm at least between foamed resin pressed by a casing. SOLUTION: A metal case is composed of upper and lower plates 11 and 12 provided with housing spaces for an element. On the upper plate 11, through holes 13 are formed for passing sounds. After the element so the like is housed, they are fixed by folding a projection formed on the upper plate 11. In this case, the through holes 13 can be formed on the lower plate 12 as well. A diaphragm 14 can use alloy or the like and sticks a piezoelectric ceramic plate 10 at its central part. The electrodes of silver or the like are formed on both sides of piezoelectric ceramic plate 10 and lead wires 15 are connected to the respective electrodes. The electrode on the plate stuck to the diaphragm 14 can be connected by soldering the lead wire to the diaphragm 14. The diaphragm 14 is held at its peripheral sections by foamed resin 17 and 18. |
