JPS5834878Y2 - speaker - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a speaker using a ceramic bimorph.

As shown in Fig. 1, a conventional speaker using a ceramic bimorph has piezoelectric elements 1 and 2 equipped with electrodes on both sides.
It is a double-sided bimorph polarized as shown by the - symbol.

This ceramic bimorph speaker utilizes flexural vibration, and the first resonance has a vibration mode as shown in FIG.

In general, the piezoelectric ceramic composition that makes up the piezoelectric elements 1 and 2 is very hard, so it is difficult to reproduce sounds at low frequencies unless the diameter is made large or extremely thin. In addition, it is difficult to produce thin products, and if they are made too thin, they may be damaged during large inputs.
There is a risk of deformation, and there are limits to practical use.

The present invention eliminates the above-mentioned drawbacks of the prior art.

Hereinafter, one embodiment of the present invention will be described with reference to FIG. 3. Reference numeral 03 represents a magnetic circuit constructed by incorporating a magnet 5 and a pole piece 6 into a yoke 4, and a frame 7 is mounted on the upper part of this magnetic circuit 3. A ceramic bimorph 10 is attached to the frame 7 via a ring 8 and a flexible edge 9 is attached to the periphery thereof.

This ceramic bimorph 10 has a configuration in which electrodes are formed on both sides and polarized piezoelectric elements are bonded together.

Further, a voice coil 12 that fits into the magnetic gap 11 of the magnetic circuit 3 is coupled to the lower surface of the ceramic bimorph 10.

This voice coil 12 is attached to the first resonance node, which is about 60% of the diameter of the ceramic bimorph 10.

With this configuration, the ceramic bimorph 10 reproduces high frequencies, and applies an input signal to the voice coil 12 for relatively low frequencies to operate as an electrodynamic type, so that the ceramic bimorph 10 vibrates as a plane diaphragm. It is something that makes you

Since the voice coil 12 is attached to the first resonance node of the ceramic bimorph 10, even when the ceramic bimorph 10 reproduces high frequencies, the voice coil 12 does not interfere with the vibration. Since the voice coil 12 does not rub against the magnetic gap 11, the sound quality does not deteriorate.

Further, since the ceramic bimorph 10 is a capacitive load, the dividing network is not necessarily required because low frequencies are not applied to the ceramic bimorph 10.

In the above embodiment, the frame 7, the ring 8, and the flexible edge 9 are provided on the magnetic circuit 3. It may also be configured to support the peripheral edge of.

As described above, the speaker of the present invention uses a ceramic bimorph to reproduce high frequencies, and uses a voice coil to vibrate the ceramic bimorph as a flat diaphragm to reproduce low frequencies. As a result, the playback band can be greatly expanded without deteriorating the sound quality, making it possible to put it into practical use.

[Brief explanation of drawings]

FIG. 1 is a configuration of a speaker using a ceramic bimorph, FIG. 2 is an explanatory diagram showing the same vibration mode, and FIG. 3 is a sectional view showing an embodiment of the speaker of the present invention. 3... Magnetic circuit, 9... Flexible edge, 10... Ceramic bimorph, 11
...Magnetic gap, 12...Voice coil.

Claims (1)

[Scope of utility model registration request] A speaker in which a voice coil is coupled to the first resonance node of a ceramic bimorph whose peripheral portion is supported by a flexible edge, and the voice coil is fitted into a magnetic gap of a magnetic circuit.