JP2002064231A - Piezoelectric light-emitting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light-emitting device that generates large electromotive force, even with small stress, and which has a simple structure, compact size, and is highly durable. SOLUTION: An electrode on the surface of a piezoelectric ceramic plate is divided and a light-emitting diode is directly soldered, thus providing the improved light-emitting device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light-emitting device for causing a light-emitting body to emit light and visually recognize the light-emitting device. And a light emitting device.

[0002]

2. Description of the Related Art Conventionally, a light emitting device utilizing this kind of piezoelectric ceramics for light emission of a light emitting diode or the like is a piezoelectric ceramic plate 2 having electrodes 6 formed on both sides as shown in FIG.
The light emitting diode 5 is connected to the piezoelectric ceramic plate 2 by a lead wire 8 and a bending stress is applied to the piezoelectric ceramic plate 2 to cause the light emitting diode 5 to emit light by an electromotive force.

[0003] Japanese Patent Application Laid-Open No. 11-253071 discloses a piezoelectric unimorph element 11 fixed to an end of a cylindrical container 9 as shown in FIG.
There is disclosed a proposal for causing a light emitting diode to emit light by using an electromotive force generated by piezoelectric ceramics when the light emitting diode collides with the light emitting diode.

However, since the piezoelectric unimorph element 11 presented here is fixed to the end of the cylindrical container 9, the vibration caused by the impact applied to the piezoelectric unimorph element 11 by the sphere 10 does not continue, but immediately. The light emitting element emits light for a very short time, and the electromotive force generated by the piezoelectric element is insufficient to cause the light emitting diode to emit light.

[0005] The large shape also hinders practical use.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of such a background, and provides a small-sized light emitting device which has a large electromotive force even with a small stress, has a simple structure, is durable, and has a high durability. What you want to do.

[0007]

That is, in a light emitting device according to the present invention, in a piezoelectric bimorph in which two piezoelectric ceramic plates are bonded together with surfaces having the same polarity, approximately the surface of one of the piezoelectric ceramic plates of the piezoelectric bimorph is formed. The electrode was divided, the other electrode on the surface of the piezoelectric ceramic plate was configured to be electrically connected to the divided electrode, and the anode terminal and the cathode terminal of the light emitting diode were directly connected to the divided electrode. Therefore, a small-sized light emitting device having a large electromotive force even with a small stress, a simple structure, and a high durability can be obtained.

[0008]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 3 shows an embodiment of the present invention.
In the piezoelectric bimorph according to the present invention, as shown in FIG. 3B, one piezoelectric ceramic plate 2 is provided with two electrodes 6a and 6b divided on one surface, and the other surface is provided with an electrode 6c extending over the entire surface. Is attached.

The other piezoelectric ceramic plate 2 has electrodes 6d and 6e on both sides, respectively.
And 6d are not attached to the ends, and the two piezoelectric ceramic plates 2 form the piezoelectric bimorph 7 by bonding the electrodes 6c and 6d having the same polarity.

Further, as shown in FIG.
f, the electrodes 6a and 6e are electrically connected, and the land electrodes 1 of the electrodes 6a and 6b are structured such that the anode terminal and the cathode terminal of the light emitting diode are directly connected by the solder 4.

With such a structure, when vibration or impact is applied from the outside, the piezoelectric bimorph 7 is displaced to generate an electromotive force, and the light emitting diode 5 electrically connected emits light. .

FIG. 4 shows time on the horizontal axis and electromotive force on the vertical axis.
The light emitting device having the conventional configuration is indicated by a dotted line, and the light emitting device according to the present invention is indicated by a solid line. It can be seen that the light emitting device according to the present invention has a larger electromotive force and longer time than the conventional method.

Further, since the light emitting diode 5 is arranged directly on the piezoelectric bimorph 7, the size is reduced.

[0015]

As described above, according to the present invention, in a light emitting device that emits light by using an electromotive force generated when a stress of a piezoelectric element is applied, two piezoelectric ceramic plates have polarities. In a piezoelectric bimorph in which the same surfaces are bonded together, an electrode on the surface of one piezoelectric ceramic plate of the piezoelectric bimorph is roughly divided, and an electrode on the surface of the other piezoelectric ceramic plate is electrically connected to the divided electrode. Since the anode terminal and the cathode terminal of the light emitting diode are directly connected to the divided electrodes, the vibration caused by the shock applied to the piezoelectric element is attenuated for a longer time, resulting in a large electromotive force and This makes it possible to provide a piezoelectric light emitting device that can visually recognize the amount of light emitted from the device.

Further, since the light emitting diode 5 is directly disposed on the piezoelectric bimorph 7, the size is reduced.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a conventional light emitting device.

FIG. 2 is a perspective view showing a conventional light emitting device.

FIG. 3 is a diagram showing one embodiment of the present invention.

FIG. 4 is a graph illustrating the effect of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Land electrode 2 Piezoelectric ceramic board 3 Adhesion part 4 Solder 5 Light emitting diode 6 Electrode 7 Piezoelectric bimorph 8 Lead wire 9 Container 10 Sphere 11 Piezoelectric unimorph

Claims (1)

[Claims] In a piezoelectric bimorph in which two piezoelectric ceramic plates are bonded together with surfaces having the same polarity, an electrode on one piezoelectric ceramic plate surface of the piezoelectric bimorph is divided, and an electrode on the other piezoelectric ceramic plate surface is divided. Is configured to be electrically connected to the divided electrode,
The anode terminal and the cathode terminal of the light emitting diode are directly connected to the divided electrodes.