JPH0224320Y2 - - Google Patents

Description

[Detailed description of the invention] <Industrial application field> The present invention relates to a piezoelectric buzzer. Specifically, the invention applies an alternating voltage to an input electrode to cause a bending strain on a piezoelectric element plate and generate a ringing sound. At the same time, the visual display device is driven by the potential generated by the distortion.

<Prior Art> A piezoelectric buzzer that generates a sound by applying an alternating voltage to an input electrode to cause a bending strain on a piezoelectric element plate is known as a piezoelectric buzzer.

By the way, the piezoelectric buzzer can be used as a monitor device,
It is used as an alarm for smoke detectors to alert supervisors, but in noisy environments, the sound alone may not be sufficient. Moreover, the information transmission function is limited only by the sound.

The object of the present invention is to provide a piezoelectric buzzer that can generate the above-mentioned sound and also provide a visual display in synchronization with the sound.

<Means for Solving the Problems> In the present invention, a piezoelectric element plate polarized in the thickness direction is attached to one surface of a disk-shaped metal diaphragm fixed at the periphery, and further, on the upper surface of the piezoelectric element plate, An output electrode is formed at the center position, an input electrode to which an alternating voltage is applied is formed on the other surfaces, a common electrode is formed on the lower surface of the piezoelectric element plate, and a voltage is applied to the output electrode. It is characterized in that a driving visual display device is connected.

<Operation> By applying an alternating voltage of an audible frequency corresponding to the natural resonance frequency of the metal diaphragm between the output electrode and the common electrode and excitation, the piezoelectric element vibrates and generates a ringing sound. do. Due to such vibration, the piezoelectric element plate has a maximum amplitude of approximately six times that of the peripheral portion at the center thereof, and a large strain occurs. Therefore, a potential difference is generated at the output electrode,
An alternating voltage that is synchronized with the vibration frequency is extracted. The alternating current voltage drives a visual display device connected to the output electrode to provide a visual display using light or the like synchronized with the sound.

<Example> An example of the present invention will be described with reference to FIGS. 1 and 2.

Reference numeral 1 denotes a disk-shaped metal diaphragm, on the top surface of which is provided a piezoelectric element plate 3 made of a material such as lead zirconate titanate and polarized in the thickness direction, avoiding the periphery 2 of the metal diaphragm 1. It is pasted. A common electrode 4, which is an input/output electrode to be described later, is provided on the lower surface of the piezoelectric element plate 3, and the common electrode 4 comes into contact with the metal diaphragm 1 and is electrically connected. Further, on the piezoelectric element plate 3, an output electrode 5 is located at the center position.
However, the input electrodes 6 to which an alternating voltage is applied to the other surfaces are formed by means such as vapor deposition while being electrically non-conductive with each other.

A light emitter 10 such as a light emitting diode or liquid crystal is connected to the input electrode 6. The other terminal of the first light emitting body 10 may be connected to the metal diaphragm 1 or may be grounded.

Incidentally, when connecting the light emitter 10, a transformer 11 may be interposed as shown in FIG. 3 in order to boost the voltage to the required voltage for driving the light emitter 10. .

In the embodiment, holding the peripheral edge 2,
An alternating voltage having a frequency matching the natural resonant frequency of the composite body consisting of the piezoelectric element plate 3 and the metal diaphragm 1 is applied between the input electrode 6 and the metal diaphragm 1 (common electrode 4).

Therefore, the metal diaphragm 1 and the piezoelectric element plate 3 are as follows:
An amplitude of a frequency equal to the above-mentioned frequency is generated, and the amplitude is maximum at the center, and an alternating voltage is generated at the input electrode 6 due to the distortion accompanying the amplitude. Therefore, the voltage is applied to the light emitting body 10, causing a predetermined light emission. In this case, although the light emitting body 10 emits intermittent light, it is visually recognized as continuous light because of its high frequency.

<Effect of the invention> As described above, the present invention causes a piezoelectric element plate to generate a sound, and also causes a visual display device to be driven by the piezoelectric element plate to generate a visual display that is synchronized with the sound. (a) It complements the alerting function using the sound described above, and enables visual confirmation even in noisy environments or for those who are hard of hearing, thereby enhancing the above-mentioned function.

(b) By causing a change in the display mode of the visual display device along with the sound, an interesting display device can be provided.

(c) By displaying a display associated with the sound, it is possible to make it possible to understand the meaning of the sound.

It has excellent effects such as

[Brief explanation of the drawing]

The accompanying drawings show an embodiment of the present invention; FIG. 1 is a perspective view, FIG. 2 is a longitudinal side view, and FIG. 3 is a longitudinal side view of another embodiment. 1; metal diaphragm, 3; piezoelectric element plate, 5; output electrode, 6; input electrode, 10; light emitter, 11; transformer.

Claims (1)

[Scope of utility model registration request] A piezoelectric element plate polarized in the thickness direction is adhered to one surface of a disk-shaped metal diaphragm whose periphery is fixed, and an output electrode is formed on the upper surface of the piezoelectric element plate at its center position. An input electrode to which an alternating voltage is applied is formed on the surface, a common electrode is formed on the lower surface of the piezoelectric element plate, and a visual display device driven by voltage application is connected to the output electrode. piezoelectric buzzer.