JPH0578919B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a display device in which an excited luminescent material such as a rare earth element or a transition metal element is enclosed in an aluminum anodic oxide film to produce electric field excited luminescence. More particularly, the present invention relates to a display device characterized by its electric field excitation structure.

``Prior Art'' A luminous element is a luminous element in which a phosphor such as a rare earth element such as eurobium or terbium is activated and encapsulated in a porous film obtained by anodizing a high-purity aluminum plate or foil. , was previously proposed by the applicant of the present application in JP-A-60-182689 and JP-A-60-205989. As a means of activating and encapsulating a phosphor in a porous film formed by anodizing, the porous film is immersed in a phosphor salt solution such as a eurobium salt solution or a terbium salt solution, and then re-anodizing is performed. You can adopt the method of In such a method, in order to prevent the phosphor sealed in the porous film from leaking out, the pores filled with the phosphor are sealed, and the fluorescent material inside the pores of the porous film is sealed. In order to increase the amount of encapsulation and stability, it is also possible to perform a secondary anodic oxidation treatment at a lower voltage after the first anodization treatment step to form even finer encapsulation holes at the bottom of each hole.

In addition to ultraviolet rays or electron beams, electric field excitation means or the like can be used as a means for excitation of luminescence of such a luminous element. In the case of electric field excitation means, for example, a high purity aluminum plate 2 as shown in FIG. As described above, a so-called Nesa glass 4 having a transparent electrode 5 formed thereon is placed on the film 3 of the light-emitting device 1 having a porous light-emitting film 3 in which a phosphor is encapsulated, and a gap is formed between the aluminum plate 2 and the transparent electrode 5. By applying an alternating current voltage E to the phosphor, it is possible to emit light in, for example, orange, red, or yellow-green depending on the type of activated encapsulated phosphor.

"Problems to be Solved by the Invention" When constructing a display device using such a light emitting element, if the transparent electrode 5 is simply formed in close contact with the porous light emitting film 3 as described above, the transparent electrode 5
Since abnormal discharge occurs between the light-emitting film 3 and the light-emitting film 3, causing dielectric breakdown of the film 3, the light-emitting element 1 is destroyed in a short period of time, making it extremely difficult to expect stable light-emitting operation. The problem is that the luminance is low.

``Means for Solving the Problems'' Therefore, the present invention provides an insulating film, an insulating material, and an insulating film between the above-mentioned luminescent element in which an excited luminescent material is encapsulated in an aluminum anodic oxide film and a transparent electrode provided on this element. The present invention provides a display device configured to achieve stable light emitting operation and improvement in luminance by forming a gap of several μm to several tens of μm with an intervening polymer film or an insulating metal oxide film. be. Such a gap is formed by the above-mentioned inclusions according to the required characters, symbols, figures, etc. required for the display device, and the existence of this gap causes the gap between the porous luminescent film and the transparent electrode to It is possible to prevent abnormal discharge as in the conventional case and perform a good light emitting operation.

"Embodiments" Hereinafter, the present invention will be described in further detail based on the illustrated embodiments. In FIGS. 1 to 6, the same reference numerals as in FIG. 7 indicate the same components, and FIG. As shown in FIG. 2, a required gap 6 is formed between the porous luminescent coating 3 and the transparent electrode 5. The relationship between the gap 6 and brightness is as shown in Figure 2, where the horizontal axis is the gap G (μm) and the vertical axis is the brightness B (cd/m ³ ). The gap range can be set to about 2 to 19 μm, preferably about 5 to 18 μm.

Such a gap can be constructed, for example, as shown in FIG. 3, by interposing an insulating film 7 such as a polyester film between the porous light emitting film 3 and the transparent electrode 5 to provide a gap 8 within the above range. This gap 8 can be obtained by punching an insulating film 7 into letters 8A, 8B such as M, N, etc., as shown in FIG. Instead of interposing the insulating film 7, an insulating metal oxide film 9 such as aluminum oxide or titanium oxide is deposited on the porous light emitting film 3 of the light emitting element 1 by a sputtering method or the like to a thickness of several μm or more as described above. It is also possible to apply the film to a thickness of several tens of μm and leave gaps such as letters 8A and 8B in the same manner as above. Similarly, such an insulating metal oxide film 9 can also be formed of an insulating polymer film formed by screen printing, photolithography, or the like. The transparent electrodes to be formed on the Nesa glass 4 corresponding to the shapes of the gaps 8 such as the characters 8A and 8B as described above can also be formed as appropriate, such as 5A and 5B as shown in FIG. In a display device equipped with a gap formed in the above manner, if an AC voltage E of, for example, about 280V to 380V is applied, it is possible to suitably prevent the occurrence of abnormal discharge as in the conventional case, and to achieve uniform and high brightness. can maintain stable luminescence.

The luminescent material to be enclosed in the porous luminescent film 3 is not limited to the rare earth elements mentioned above, but may include Mn,
One or two of transition element metals such as Co, Zn, or Ce, or an alloy thereof can be used as appropriate, and the encapsulation means include the above-mentioned electrochemical method, as well as direct injection into the porous film. A method of injecting the above-mentioned luminescent material by ion implantation is also suitable. Such a porous luminescent coating 3 can be peeled off from the aluminum plate 2 as a base material by a reverse electrolytic method.

"Effects of the Invention" As described above, the display device according to the present invention forms a required gap between the porous luminescent film encapsulating the luminescent material and the transparent electrode, and uses the gap to display characters, symbols, etc. Since the structure is configured to perform a desired electroluminescence operation such as a figure, it is possible to suitably prevent dielectric breakdown of the porous film due to abnormal discharge as in the conventional case, and achieve a stable and uniform high-intensity light emission operation. Therefore, it is possible to perform a stable display function for a long period of time.

[Brief explanation of the drawing]

FIG. 1 is a conceptual partial enlarged sectional configuration diagram of a display device in which a gap is provided between a porous light emitting film and a transparent electrode according to the present invention, and FIG.
Fig. 1 is a graph showing the relationship between the gap and luminance; Fig. 3 is a partially enlarged cross-sectional view similar to the above when the gap is made of an insulating film; and Fig. 4 is a graph showing the relationship between the gap and the luminance. FIG. 5, which is an explanatory diagram of the method of punching out characters to form gaps, shows an embodiment in which an insulating metal oxide film or polymer film is coated on a porous luminescent film to form the required display gap. 6 is a conceptual perspective configuration diagram of the light emitting element shown in FIG.
The figure shows an example in which the transparent electrode on the Nesa glass side is configured to correspond to the shape of the display gap, and FIG. 7 is a conceptual cross-sectional configuration diagram of a conventional display device. 1: Luminous element, 2: Aluminum plate, 3: Porous luminescent film, 4: Nesa glass, 5: Transparent electrode,
6, 8: Display gap, 7: Insulating film,
9: Insulating metal oxide film or polymer film.

Claims (1)

[Scope of Claims] 1. A display device configured to include a luminescent element in which an excited luminescent material is enclosed in an aluminum anodic oxide film, and means for forming a gap between a transparent electrode provided on the luminescent element. . 2. The display device according to claim 1, wherein the gap is formed by interposing an insulating film. 3. The display device according to claim 1, wherein the gap is formed by interposing an insulating metal oxide film. 4. The display device according to claim 1, wherein the gap is formed by interposing an insulating polymer film. 6. The display device according to any one of claims 1 to 4, wherein the gap is configured to be several μm to several tens of μm.