вход по аккаунту



код для вставкиСкачать
Patent Translate
Powered by EPO and Google
This translation is machine-generated. It cannot be guaranteed that it is intelligible, accurate,
complete, reliable or fit for specific purposes. Critical decisions, such as commercially relevant or
financial decisions, should not be based on machine-translation output.
1Specification 1, Name of Invention
Piezoelectric speaker
3. Detailed description of the invention The present invention relates to a piezoelectric speaker
having a piezoelectric vibrator as a drive source, which is excellent in damping of the
piezoelectric vibrator at the time of secondary resonance and in eliminating interference between
the piezoelectric vibrator and the frame. It is an object of the present invention to provide one
having acoustic characteristics. Recently, development concerning a piezoelectric type spill force
using a piezoelectric vibrator as a drive source has been actively promoted. As shown in the
figure, a plurality of electrodes are formed on a disc-shaped piezoelectric ceramic plate, and a
cone-shaped diaphragm is formed at the center of the upper surface of the piezoelectric vibrator
1 formed in a plate shape. The central portion 2 is joined, and the peripheral portion of the
diaphragm 2 is adhesively bonded to the peripheral portion of the cap-like frame 3. The
piezoelectric vibrator 1 vibrates along its diameter as shown in FIGS. 2A and 2H at the time of
the first-order resonance. During the first half of each vibration, the central portion of the
piezoelectric vibrator 1 is bent upward as indicated by a solid line, and the peripheral portion is
bent downward. During the latter half of the cycle, the opposite oscillation occurs as indicated by
the broken line. Then, two nodes 4 are formed along the diameter, and the nodes 4 draw a ring.
Further, at the time of the second resonance, the piezoelectric vibrator 1 vibrates as shown in
FIGS. 3A and 3B, and the second resonance has a frequency higher than that of the first
resonance. Two concentric node rings 6, 6 are formed on the surface. In the configuration in
which the piezoelectric vibrator 1 vibrating in this manner is suspended by the end plate 1 by the
diaphragm 2, as shown by the broken line in FIG. Moreover, interference occurs between the
piezoelectric vibrator 1 and the frame 3 in the vicinity of the second resonance, causing a large
dip in frequency sound pressure characteristics, and there is a drawback that the characteristics
can not be made flat as a whole. The present invention eliminates the above-mentioned
conventional drawbacks. An embodiment of the present invention will be described below with
reference to FIG. A frame 7 is formed in a cap shape by a synthetic resin or the like, and a
peripheral edge portion of a diaphragm formed in a cone shape is bonded to an edge portion of
the frame 7 by an adhesive or the like. A piezoelectric vibrator 9 such as a flat electric bimorph
constructed by connecting a disc-shaped piezoelectric ceramic plate provided with a plurality of
electrodes on both sides of a metal plate at the center of the diaphragm 8. The top center of the
is joined. Furthermore, between the lower surface of the piezoelectric vibrator 9 and the inner
bottom portion of the frame 7, there is a cylindrical elastic body 1o having a diameter equal to
the diameter of the small diameter node ring 6 at the second resonance shown in FIG. It is
arranged. That is, the two ends of the cylindrical elastic body 10 are in close contact or
adhesively bonded near the small-diameter node ring 6 at the primary resonance of the
piezoelectric vibrator 9.
The cylindrical elastic body 10 is made of a flexible material such as soft urethane foam or
silicone rubber, and damps the vibration of the piezoelectric vibrator 9 within the small diameter
nodal ring 6 of the secondary resonance. Interference between the inner bottom and the
piezoelectric vibrator 9 is prevented. The interference between the frame 7 and the piezoelectric
vibrator 9 is reversed, as shown in FIG. 3, because the vibration form in the small diameter node
ring 6 at the second resonance and the vibration form outside the node ring 6 are completely
opposite, Since this phase is opposite, a tip like the conventional characteristic shown in FIG. 5 is
generated by this reverse phase, but interference is eliminated by absorbing the vibration in the
joint ring 6 with the cylindrical elastic body 1 o. The flat frequency sound pressure characteristic
as shown by the solid line in the figure is obtained. As described above, since the piezoelectric
speaker according to the present invention is configured, the characteristic fluctuation due to the
interference caused by the damping of the piezoelectric vibrator at the second resonance and the
reflection of the anti-phase vibrating portion of the piezoelectric vibrator on the frame In
addition, the assembly process can be simplified because the cylindrical elastic body on the
frame, the piezoelectric vibrator on the frame, and the diaphragm are also stacked in the
assembly, so that the assembly process is simplified, which is advantageous in cost. It has the
advantage of being able to produce and is an industrial value dog.
4. Brief description of the drawings. FIG. 1 is a half sectional view showing a conventional
piezoelectric speaker, FIG. 2A and FIG. 2B are explanatory views showing a vibration form of a
general piezoelectric vibrator at primary resonance, FIG. 3A and 3B are explanatory views
showing the vibration form at the time of the second secondary resonance, FIG. 4 is a half
sectional view showing an embodiment of the piezoelectric type speaker of the present invention,
and FIG. It is a frequency sound pressure characteristic view of a shape speaker. 7 ,,,,,, frame, 8
,,,,,, diaphragm, e ,,,,,. Piezoelectric vibrator, 10, ..., cylindrical elastic body. \ Name of agent
Attorney Nakao et al. 1 person Fig. 1 EndPage: 2 Fig. 3 Fig. 4 Fig. 5 EndPage: 3
Без категории
Размер файла
10 Кб
description, jps5563199
Пожаловаться на содержимое документа