JPH11185963A - Electroluminescence - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture electroluminescence giving less unevenness in light emitting luminance at comparatively low cost by forming a light emitting layer of electroluminescence(EL) composed by accumulating a transparent upper electrode, a light emitting layer, a dielectric layer, and a lower electrode sequentially into a light emitting body powder layer in which light emitting body powders are sprayed uniformly. SOLUTION: An electroluminescent 10 light emitting layer 30 has a three layer structure in which an electrically conductive resin coated layer 30a, a light emitting body powder layer 30b, and an insulation resin coated layer 30c are formed sequentially. This EL 10 is manufactured by forming an upper electrode 20 in which an ITO electrode is vapor-deposited on a transparent plastic film and printing a material turned into a paint by mixing ITO powder which is an electrically conductive resin paint and tin powder into resin on it to form the electrically conductive resin coated layer 30a. Light emitting body powder 11 is uniformly sprayed and bonded on a whole surface of the electrically conductive resin coated layer 30a, and then free light emitting body powder 11 is removed to form the light emitting body powder layer 30b so that uniform light emitting surface giving less shade is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to electroluminescence (hereinafter, referred to as EL).

[0002]

2. Description of the Related Art As a conventional EL structure, for example, as shown in FIG. 6, a transparent upper electrode 2, a light emitting layer 3, a dielectric layer 4, and a lower electrode 5 are laminated on a plastic film 7a in this order. Many have been done. The signal lines from the upper electrode 2 and the lower electrode 5 are gathered at one end of both electrode plates, and are connected to a driving-side substrate via a cable 6 therefrom.
Finally, in order to obtain an insulating effect and a moisture-proof effect, the entire EL1 is covered with a transparent plastic film 7b. Light emission of the EL 1 having the above structure is obtained by applying an AC voltage between the upper electrode 2 and the lower electrode 5 via the cable 6.

The EL1 having such a structure is generally manufactured by the following method. First,
The transparent upper electrode 2 is made of a transparent plastic film 7a.
IT obtained by doping tin oxide with indium oxide
A transparent metal film is formed by evaporating O (Indium Tin Oxide) powder, and an upper electrode pattern is formed by etching the metal film. In addition, other than such etching, it is also possible to form a paint by mixing ITO powder with a transparent resin, and to form this by printing. Next, the light-emitting layer 3 is formed into a paint by adding a trace amount of an activator of a metal or a halogen element to a fluorescent matrix of zinc oxide (ZnS),
This can be formed on the upper electrode 2 by screen printing. If the area is small, pad printing can be performed, but in this case, since the thickness in one printing is in the range of about 5 to 10 μm, 3 to 5 printings are required, and the number of manufacturing steps is reduced. And costly and impractical. The thickness of the light-emitting layer 3 is preferably in the range of 20 to 40 μm.
This method is practical because it requires only two printings and can perform printing in a wide range, and has a great cost advantage. Next, a material having a high withstand voltage is used for the dielectric layer 4 in order to protect the light emitting layer 3 from electrical insulation breakdown. Such a material is barium titanate, which is formed by screen printing on the light emitting layer 3 with a coating material in which barium titanate is dispersed. Lower electrode 5
Is formed by screen printing on the dielectric layer 4 with a silver paste or a carbon paste. Finally, sealing is performed by bonding or thermocompression so as to cover the whole with a transparent plastic film 7b. This plastic film 7b is provided for the purpose of an insulating effect and a moisture-proof effect.

[0004]

As described above, the EL
The light-emitting layer 3 serving as the light-emitting source 1 is generally formed by a screen printing method. This is because, as described above, the number of times of printing is small, and a large area can be printed, so that mass production is possible and cost merit is great. However, as shown in FIG. 7, in the screen printing method, a mesh screen is formed by laying a mesh screen on the surface of the resin binder 12 to be printed and printing the fluorescent particles 9 on the screen. There is a problem that the fluorescent particles 9 are not arranged uniformly under each of the screens 8. That is, the fluorescent particles 9 just below the net 8
Is different from the dispersed state of the fluorescent particles 9 between the portion of the net 8 and the portion of the mesh layer which is below, the thickness of the light emitting layer 3 is not uniform when viewed over the entire surface of the light emitting layer 3. Problem. The specific gravity of the fluorescent particles 9 is about 3 times smaller than that of the resin binder 12 forming the light emitting layer 3.
Since the fluorescent particles 9 are nearly twice as large, the fluorescent particles 9 sink too quickly into the resin binder 12, which also causes the fluorescent particles 9 not to penetrate directly below the net 8. Thus, the fluorescent particles 9
Is uneven at the surface layer of the light emitting layer 3 to cause unevenness in the brightness of the light emitting layer 3, and the brightness becomes low where the dispersion of the fluorescent particles 9 is small and small, whereby uniform light emission is obtained as a whole EL1. There was no problem.

Accordingly, an object of the present invention is to directly scatter the luminescent powder on the luminescent layer, or to form the luminescent powder by pressing the luminescent powder, thereby uniformly arranging the luminescent powder on the surface of the luminescent layer, and thereby obtaining the luminous brightness unevenness. This makes it possible to manufacture EL with a small amount at a relatively low cost.

[0006]

In order to solve the above-mentioned problems, an EL according to a first aspect of the present invention comprises a transparent upper electrode,
In electroluminescence in which a light emitting layer, a dielectric layer, and a lower electrode are sequentially stacked, the light emitting layer has a light emitting powder layer formed by uniformly scattering light emitting powder.

[0007] An EL according to a second aspect of the present invention is an electroluminescence device comprising a transparent upper electrode, a light-emitting layer, a dielectric layer, and a lower electrode, which are sequentially laminated. And a phosphor powder layer formed by pressing the powder after spraying.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of an EL according to the present invention will be described in detail with reference to the accompanying drawings. The outline of the transparent plastic film is omitted in each of the cross-sectional views shown in the drawings. First, the configuration of the first embodiment is shown in FIG. The EL 10 in this embodiment is configured by sequentially laminating an upper electrode 20, a light emitting layer 30, a dielectric layer 40, and a lower electrode 50. In particular, the light emitting layer 30 has a three-layer structure in which a conductive resin coating layer 30a, a luminous body powder layer 30b, and an insulating resin coating layer 30c are formed in this order. The manufacturing method of the EL 10 in this embodiment is to form an upper electrode 20 on which a ITO electrode is deposited on a transparent plastic film (not shown), and then form a conductive resin paint such as ITO powder or tin powder. Is mixed with a resin to form a coating, and the conductive resin coating layer 30a is formed by printing. After a while, when the conductive resin coating layer 30a is in a semi-cured state, the phosphor powder 11 is formed.
Is uniformly scattered over the entire surface of the conductive resin coating layer 30a to be adhered and completely cured. Thereafter, by removing the phosphor powder 11 liberated from the conductive resin coating layer 30a to form the phosphor powder layer 30b, a uniform light-emitting surface with less shading can be obtained. After these steps, an insulating resin coating layer 30c is formed on the phosphor powder layer 30b by a printing method using a non-conductive resin paint. On the insulating resin coating layer 30c formed above, a dielectric layer 40 is formed by a printing method using a coating material in which barium titanate is dispersed, and further, a lower electrode 50 is formed by a paste of silver, carbon or the like.
To form Finally, a transparent plastic film (not shown) is bonded and sealed to the outer surfaces of the upper electrode 20 and the lower electrode 50 to complete the process. In this structure and manufacturing method,
Since the luminous body powder 11 is uniformly arranged without any gap on the entire surface between the conductive resin coating layer 30a and the insulating resin coating layer 30c, there is no unevenness in emission luminance, and the emission luminance is overall. Up.

FIG. 2 is different from the structure of the first embodiment in that the insulating resin coating layer 30c formed on the luminescent powder layer 30b is removed from the components of the luminescent layer 30. .
The manufacturing method in this case is to form the phosphor layer 30a on the conductive resin coating layer 30a by the same means as in the first embodiment, and then print and form the dielectric layer 40 and the lower electrode 50. . Even in such a structure, since the phosphor powders 11 are uniformly arranged on the dielectric layer 40 without any gaps, unevenness in emission luminance does not occur, and the luminance can be further increased.

FIG. 3 shows a third embodiment of the EL 10 according to the present invention. The EL 10 shown here has a different stacking order from those of the first embodiment and the second embodiment, and is configured by stacking a lower electrode 50, a dielectric layer 40, a light emitting layer 30, and an upper electrode 20 in this order. Is done. The luminescent layer 30 is formed by forming a luminescent powder layer 30b on an insulating resin coating layer 30c. In particular, the luminescent powder layer 30b is formed of an insulating resin on which the luminescent powder 11 is disposed. It is formed with a little biting into the surface layer of the coating layer 30c. The EL 10 having this structure is manufactured by the following method.
First, the lower electrode 50 is printed and formed on a plastic film (not shown), and then dried and cured. Then, a dielectric layer 40 is formed thereon by printing, which is also dried and cured.
Further, an insulating resin coating layer 30c is formed on the dielectric layer 40 by printing. In a semi-cured state where the printed insulating resin coating layer 30c is not completely cured, the phosphor powder 11 is evenly dispersed without gaps, and the phosphor powder 11 is further spread on the surface of the insulating resin coating layer 30c. Press and let go. After that, the phosphor powder 11 is completely cured, and the luminous body powder 11 remaining on the surface of the insulating resin coating layer 30c is removed. And
The upper electrode 20 is formed on the phosphor powder 11 pressed into the surface of the insulating resin coating layer 30c. The upper electrode 20 may be formed by depositing ITO or depositing ITO, as in the first and second embodiments.
It can be formed by printing a powdered powder. Finally, a transparent plastic film (not shown)
Is bonded and sealed to the outer surfaces of the upper electrode 20 and the lower electrode 50 to complete the process.

In the fourth embodiment shown in FIG. 4, the light emitting layer 30 is formed only by the light emitting powder layer 30b without the insulating resin coating layer 30c from the configuration of the third embodiment. As in the third embodiment, the lower electrode 50 and the dielectric layer 40
, And the phosphor powder 11 is directly applied to the dielectric layer 40.
And spread evenly over the top without gaps. Then, the upper portion of the scattered luminescent powder 11 is pressed or smashed while being rolled with a roller-shaped material, and the luminescent powder 11 is scattered.
Is cut into the surface portion of the dielectric layer 40 and is fixed. Thereafter, the luminescent powder 11 released from the pressed surface layer is removed to form the luminescent layer 30 composed of only the luminescent powder layer 30b. Finally, the upper electrode 20 is formed on the luminous body powder layer 30b by depositing ITO or printing it as a paint in the same manner as in the first embodiment. Finally, a transparent plastic film (not shown)
Is bonded and sealed to the outer surfaces of the upper electrode 20 and the lower electrode 50 to complete the process. Even with such a structure, high light emission luminance can be obtained because there is no luminance unevenness as in the first embodiment.

Next, an EL structure according to a fifth embodiment is shown in FIG. In this structure, a transparent upper electrode 20, a thin insulating resin film 30d, a phosphor powder 11, a dielectric layer 40, and a lower electrode 50 are laminated in this order. In this manufacturing method, first, a transparent upper electrode 20 is formed on a plastic film (not shown) by depositing an ITO electrode by a vapor deposition method or a printing method. Then, an insulating resin film 30d having a thickness of about 5 to 15 μm is formed on the upper electrode 20, and the phosphor powder 11 is uniformly dispersed in a semi-cured state. The scattered phosphor powder 11 is pressed against the insulating resin film 30d, and then completely cured to fix the phosphor powder 11 thereon. Then, after removing the extra luminous body powder 11 floating on the insulating resin film 30d, the dielectric layer 40 and the lower electrode 50 are printed and formed in this order.
Thus, the insulating resin film 3 having a thickness of about 5 to 15 μm
The phosphor powder 11 having a particle size of 15 to 25 μm is uniformly penetrated into Od, so that the phosphor powder 11 contacts the transparent upper electrode 20. Further, since the particle diameter of the luminous body powder 11 is larger than the thickness of the insulating resin film 30d, the luminous body powder 11 protrudes from the surface of the insulating resin film 30d. Therefore, the diffusion and reflection of the protruding phosphor powder 11 and the dielectric layer 40 cause the entire EL 10 to emit light more brightly.

[0013]

As described above, the EL according to the present invention is provided.
According to the method, since the light-emitting layer is provided with the light-emitting layer in which the light-emitting body powder is evenly dispersed, unevenness in the luminance of the light-emitting layer is reduced, and uniform light-emitting luminance can be obtained.

Further, since the light emitting layer is formed by uniformly spraying the light emitting powder and pressing the dielectric layer, the light emitting powder penetrates into the dielectric layer, and the adhesion between the light emitting powders is improved. As a result, more uniform light emission can be obtained, and the light emission luminance is further improved.

[Brief description of the drawings]

FIG. 1 is a sectional view of a first embodiment of an EL according to the present invention.

FIG. 2 is a cross-sectional view of a second embodiment of the EL according to the present invention.

FIG. 3 is a sectional view of a third embodiment of an EL according to the present invention.

FIG. 4 is a sectional view of a fourth embodiment of an EL according to the present invention.

FIG. 5 is a sectional view of a fifth embodiment of the EL according to the present invention.

FIG. 6 is a cross-sectional view of a conventional EL.

FIG. 7 is an enlarged cross-sectional view of a conventional EL.

[Explanation of symbols]

 REFERENCE SIGNS LIST 10 EL 11 luminescent powder 20 upper electrode 30 luminescent layer 30 a conductive resin coating layer 30 b luminescent powder layer 30 c insulating resin coating layer 40 dielectric layer 50 lower electrode

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Mitsuo Iwamura 26663 Funatsu, Kawaguchiko-machi, Minamitsuru-gun, Yamanashi Prefecture Inside Kawaguchiko Precision Co., Ltd.

Claims (2)

[Claims] 1. An electroluminescence device comprising a transparent upper electrode, a light-emitting layer, a dielectric layer, and a lower electrode, which are sequentially laminated, wherein the light-emitting layer is formed by uniformly dispersing a light-emitting powder. Electroluminescence characterized by having. 2. In the electroluminescence in which a transparent upper electrode, a light emitting layer, a dielectric layer, and a lower electrode are sequentially laminated, the light emitting layer is formed by uniformly dispersing a phosphor powder and pressing the same. An electroluminescence comprising a luminescent powder layer formed as described above.