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This translation is machine-generated. It cannot be guaranteed that it is intelligible, accurate,
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BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 (i) and (b) are side views showing the operation
of the piezoelectric ceramic, FIG. 2 is a perspective view of the piezoelectric ceramic type sou
beaker of the present invention, and FIGS. FIG. 4 is a side view showing the operation of the
speaker, and FIG. 4 is a perspective view of a conventional piezoelectric ceramic type speaker. 22
is a piezoelectric ceramic and 21 is a support. −
DETAILED DESCRIPTION OF THE INVENTION This invention relates to the improvement of a
direct emission speaker using piezoelectric ceramic. Piezoelectric ceramic acts as a piezoelectric
body by performing a polarization operation to align the polarization direction of each domain by
applying a direct current voltage in the thickness direction to the ceramic as is well known. Then,
by applying an electric field in the thickness direction, the shape is changed to perform an
electro-mechanical or 1 mechanical-electrical conversion action. 33 (2 In order to use such a
piezoelectric ceramic as an 11111 plate of a speaker, as shown in FIG. 1 (a), a bimorph in which
two piezoelectric ceramic element plates +11 are bonded with the other facing each other) It is
preferable that the piezoelectric ceramic plate or the piezoelectric ceramic element plate 1 is
attached to the metal plate 2 as shown in FIG. 1 (b). This is because the piezoelectric ceramic
having such a configuration vibrates so that its central portion is curved by applying an AC signal
(audio signal) to both electrodes, and as a result, it emits an acoustic wave. Therefore, in the
following description, the term "piezoelectric ceramic" refers to those having the two
configurations. An example of a direct emission type speaker using such a piezoelectric ceramic
is shown in FIG. In FIG. 4, reference numeral 21 denotes a support for placing the pressuresensitive ceramic 22 and 23.24 denotes leads for applying an audio signal to the front SeE
electroceramic 22 placed on the surface of the support 21. The voice signal applied from the lead
wire 23.24 vibrates the three piezoelectric ceramics 22 and emits an acoustic wave proportional
to the high voice signal to the atmosphere. When such a piezoelectric ceramic is used as a
reproduction speaker for audio, since the electroacoustic conversion efficiency is extremely low,
the radiation area is usually improved by using a plurality of piezoelectric ceramics. However, if
the radiation area is increased, the pointing beam tends to stagnate, and uniform pressure can
not be obtained in a wide hearing range. In particular, this tendency is strong because the
reproduction frequency band of the piezoelectric ceramic is at a very high level. In order to solve
the above-mentioned drawbacks, this invention effectively reduces the radiation area by
arranging a plurality of piezoelectric ceramics in a V-shape, and applies an acoustic load by a 字
形 -shaped space, and the finger and the acoustic It is a measure of the radiation efficiency. The
present invention will be described in more detail with reference to FIG. 2 and the embodiment
shown in FIG. 2. In the second section, 21 is a support and 22 is a piezoelectric ceramic.
4 two of the piezoelectric ceramic 22 become one pair, each negative side is fixed to the support
21, and each piezoelectric ceramic is disposed to be inclined in a so-called V shape spreading
toward the opening There is. A plurality of such pairs are arranged as necessary, and the tips of
the adjacent piezoelectric ceramics 22 are fixed. Each piezoelectric ceramic 22 is connected to a
lead @ 23.24. The lead wires 23. 24 may be either in series or in parallel with respect to the
respective piezoelectric ceramics 22, but the wiring is such that each piezoelectric ceramic pair
forming the V shape vibrates in the opposite direction to the same signal. Must. To explain in
more detail, the V-shaped outer surface pole of the piece of piezoelectric ceramic 1U U Mick and
the outer surface pole of the left pole, the inner surface of the V-shaped right piece and the
inward facing pole of the left side are each reeds @ 23.24 Connect electrically. Next, the
operation of the speaker having such a configuration will be described (the following description
will be made of 15 pairs of piezoelectric ceramics arranged in a V shape, but the same applies to
a plurality of pairs. Also, the human power signal is described as a sine wave single digit signal. )
When a half cycle of a sine wave stop is applied to the mass and the piezoelectric ceramic 22,
each piezoelectric ceramic 22 is deformed so that the central portion of the piezoelectric ceramic
is bent inward, and the volume of the V-shaped space decreases. Both airs of the V-shaped space
entrapped in the E ceramic 22 are pushed out in the direction of the open [] force. (Fig. 3 (a)) On
the other hand, when a negative half cycle is applied, the center of each piezoelectric ceramic 22:
1 is deformed so as to curve to the outside ILI (the volume of the V-shaped space is increased)
Therefore, air flows into the V-shaped space surrounded by the Sanoh-type ceramic from the
opening (FIG. 3 (b)) Thus, according to the polarity of the signal applied to the piezoelectric
ceramic 22, the air of the V-shaped space The electric signal is converted into a sound wave G 'by
presenting an outflow and an inflow. And according to such a configuration, the directivity is
improved as a result of the reduction of the effective acoustic radiation area in the first place
where the piezoelectric ceramic is disposed in an nV shape. In other words, the directional
frequency is higher than that of the conventional configuration. Next, while the conventional one
radiates the vibration of the piezoelectric ceramic directly to the atmosphere space, this device
radiates the sound wave by the inflow and outflow of air of a certain limited V-shaped space,
There is an advantage that the acoustic load increases and the acoustic radiation efficiency
increases. Furthermore, the support 21 is not limited to a flat shape, and by making it a curved
shape, the radiation direction of the piezoelectric ceramic arranged on the support is expanded,
so that the directivity can be further expanded.
As described above, according to the present invention, it is possible to provide a structured
ceramic speaker having wide directivity and good acoustic radiation efficiency.
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