JPH07199827A - Light accumulation type light emitting device - Google Patents

Abstract

PURPOSE:To facilitate management, to prolong residual light time and to provide easy visibility by arranging a transparent light accumulation layer contg. an alkaline earth metal on a colored substrate, CONSTITUTION:A colored layer 2 is formed by printing the prescribed position on a white plate 1 for, for example, a watch dial, with colored ink or coating material of, for example, yellowish green or applying this ink or coating material thereon. The transparent light accumulation layer 3 is composed by adding about several ppm of a slight rare element to a sintered oxide of, for example, a metal and alkaline earth metal element and is formed on the plate 1 and the colored layer 2 by screen printing, etc. Al is used as the metal of the sintered oxide and Sr as the alkaline earth metal. The sintered oxide functions as a light emitting body and the rare earth element transfers to an excited state and, therefore, acts as a catalyst. As a result, the luminance is higher than the luminance of the light accumulation type light emitting body by zinc sulfide and the residual light time is >=10 times longer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a luminous type light emitting device used for a dial of a watch or the like.

[0002]

2. Description of the Related Art Generally, a luminous material containing zinc sulfide as a main component is used for a dial for a timepiece, a luminous body for an hour hand and a minute hand. From a design point of view, the phosphorescent material is mixed with a pigment of a dedicated color. Zinc sulfide has a yellowish green color. The coloring lowers the brightness and shortens the afterglow time. When it is used in a dark place, it is impossible to read characters etc. on a watch dial in about 20 minutes.
Therefore, conventionally, in order to prevent the afterglow time from being shortened, a radioactive substance such as promethium is combined to spontaneously emit light.
The above brightness is maintained.

[0003]

However, since the conventional luminous body is added with a radioactive substance to maintain the brightness, the amount of radiation is 10 according to the regulation of "Radioactive Disability Prevention Law".
Limited to less than 0 microcurie. Therefore, it cannot be used for a wall clock having a large dial area and a large amount of usage, and its use is limited to a clock having a small dial area such as an alarm clock. In addition, enormous management costs are required due to the regulations of the "Radioactive Disorder Prevention Law" mentioned above.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a phosphorescent light-emitting device which is easy to manage, has a long afterglow time, and is easy to see and has a wide range of applications. .

[0005]

In order to achieve the above object, in the luminous type light emitting device of the present invention, a transparent luminous layer containing an alkaline earth metal is arranged on a base layer colored with at least one color. It is configured.

The transparent phosphorescent layer is made of a metal oxide type sintered material. Further, the transparent phosphorescent layer,
A rare earth element is added. A light-storing layer made of a metal oxide-based sintered material to which a rare earth element is added is arranged on a base layer colored with at least one color.

[0007]

According to the light emitting device of the present invention, the luminance is higher than that of the conventional phosphorescent light emitting body made of zinc sulfide, and the afterglow time is 5 times to 8 times longer than that of the phosphorescent light emitting body made of zinc sulfide.
Time is maintained. Therefore, it can be sufficiently applied to an alarm clock and the like. Further, by changing the printing color or the coating color of the underlayer to a desired color, a luminous body similar to that colored is artificially produced.

[0008]

FIG. 1 is a sectional view showing an embodiment of a luminous type light emitting device according to the present invention. In FIG. 1, 1 is, for example, a clock dial main plate, 2 is a colored layer formed on the main plate 1,
Denoted at 3 is a transparent luminous layer formed on the colored layer 2.

The colored layer 2 is formed at a predetermined position on the white base plate 1 by printing or applying colored ink or paint such as yellowish green.

The transparent phosphorescent layer 3 is formed, for example, by adding a trace amount of a rare earth element of about several ppm to a sintered oxide of a metal and an alkaline earth metal element, and on the base plate 1 and the coloring layer 2. Are formed by screen printing or the like. A sintered oxide of a metal and an alkaline earth metal element functions as a light emitting body, and a rare earth element functions as a catalyst for transition to an excited state. Here, aluminum (Al) is used as the metal of the sintered oxide, and strontium (Sr) is used as the alkaline earth metal. The chemical formula of the sintered oxide in this case is as follows. Sr _x · Al _y · O _Z

The transparent phosphorescent layer 3 is formed by burning natural Sr, alumina ceramics, and a small amount of rare earth elements in a furnace, for example, in an atmosphere of several thousand and several hundred degrees. Then, the sintered product is pulverized into a powder form, and the powder form is formed by a screen printing method or the like by adding an acrylic resin to form a paint.

Such a transparent phosphorescent layer 3 is slightly yellowish green and has a higher transparency than conventional zinc sulfide, and as shown in FIG. 2, it is zinc sulfide (Z) which is a conventional general phosphorescent material.
It has longer afterglow and higher brightness than NS). Therefore, the colored layer 2 and the ground plate 1, which are the lower layers, can be clearly viewed through the transparent light storage layer 3. Furthermore, the transparent light storage layer 3 stores energy in response to a fluorescent lamp or sunlight, which has a large amount of ultraviolet rays. A good wavelength is about 370 nm.

FIG. 3 is a graph showing the results of measuring the afterglow time of a light emitting device according to the present invention and a conventional phosphorescent light emitting device using zinc sulfide and a self-luminous light emitting device to which promethium is added. In FIG. 3, the horizontal axis represents the irradiation time and the afterglow time, and the vertical axis represents the afterglow brightness. Further, in the figure, the curve indicated by A-1 shows the characteristics of the light emitting body according to the present invention in which the transparent phosphorescent layer 3 is arranged on the white printed color, A-2.
The curve indicated by represents the characteristics of the luminescent material according to the present invention in which the transparent phosphorescent layer 3 containing a yellow-green pigment is arranged on the white background printing color,
The curve indicated by A-3 shows the characteristics of the luminous body according to the present invention in which the transparent luminous layer 3 is arranged on the color printing color, the curve indicated by B is the luminous luminous body by conventional zinc sulfide, and the curve indicated by C. Indicate the characteristics of the self-luminous light-emitting body. As can be seen from FIG. 3, the light emitting device according to the present invention has higher luminance than the conventional light emitting body, and the afterglow time is 10 times longer than that of the phosphorescent light emitting body using zinc sulfide and is about 5 to 8 hours. is there.
As described above, since it has a long-afterglow characteristic, it can be sufficiently applied to, for example, an alarm clock, and there is no problem. Also,
By changing the printing color or the coating color of the base plate 1 or the colored layer 2 to a desired color, it is possible to artificially manufacture a phosphorescent material similar to that colored.

As described above, according to this embodiment,
Since the rare earth element is added to the colored layer 2 and the ground plate 1 which are colored in a predetermined manner, the transparent phosphorescent layer 3 made of a metal oxide-based ceramic such as alumina containing an alkaline earth metal is arranged. With the above-mentioned phosphorescent material, it is possible to realize the phosphorescent light-emitting device in various aspects similar to those colored. Further, since it does not use radioactive substances, it can be applied to large objects such as the wall of a wall clock. As a result, the applications can be expanded and the member management cost can be reduced. Furthermore, since no colorant is mixed in the phosphorescent material, the afterglow time and brightness can be maintained high.

[0015]

As described above, according to the present invention,
With one kind of phosphorescent material, it is possible to realize the phosphorescent light-emitting device of various aspects similar to those colored. Further, since no radioactive substance is used, the invention can be applied to a large area such as a clock face of a wall clock, and can be used for a wide range of applications such as a watch exterior and decoration, and the material management cost can be reduced. Further, since no colorant is mixed in the phosphorescent material, there is an advantage that the afterglow time and the brightness can be maintained high.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of a luminous type light emitting device according to the present invention.

FIG. 2 is a diagram for comparing the afterglow time of a phosphorescent light emitting device according to the present invention and a conventional phosphorescent light emitting body using zinc sulfide.

FIG. 3 is a graph showing the results of measuring the afterglow time of a light emitting device according to the present invention and a conventional phosphorescent-type light emitting device using zinc sulfide and a self-luminous type light emitting device to which promethium is added.

[Explanation of symbols]

 1 ... Base plate 2 ... Colored layer 3 ... Transparent luminous layer

Claims (3)

[Claims] 1. A phosphorescent light-emitting device, in which a transparent phosphorescent layer containing an alkaline earth metal is arranged on a base layer colored with at least one color. 2. The phosphorescent light emitting device according to claim 1, wherein the transparent phosphorescent layer is made of a metal oxide-based sintered material. 3. The luminous type light emitting device according to claim 1, wherein a rare earth element is added to the transparent luminous layer.