KR20050073342A - El device improved brightness - Google Patents

Abstract

The present invention relates to an EL element having improved luminance by connecting a plurality of EL elements in parallel, comprising: a transparent electrode layer formed on a transparent insulating substrate; A first light emitting layer formed on the transparent electrode layer; A first insulating layer formed on the first light emitting layer; A first back electrode layer formed on the first insulating layer; A second light emitting layer formed on the first back electrode layer; A second insulating layer formed on the second light emitting layer; A second back electrode layer formed on the second insulating layer, wherein the transparent electrode layer and the second back electrode are electrically connected to a first terminal electrode, and the first back electrode is electrically connected to a second terminal electrode. It is characterized by providing an EL element having improved luminance in a multilayered light emitting form.

Description

EL device improved brightness

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an EL element, and more particularly, to an EL element having improved luminance having a multi-layered light emitting structure by connecting a plurality of EL elements in parallel.

In general, the EL element is thin and light, and is used as a backlight for an LCD of a mobile phone due to uniform surface light emitting characteristics and convenience of manufacturing.

The above-described EL element is a thin film type EL element in which a light emitting layer is formed by dispersing a phosphor in a material having a high dielectric constant, a light emitting layer, and an insulating layer by electron beam (e-beam), high frequency sputtering, or the like. A light emitting diode (LED), a semiconductor laser, or the like is a kind of the injection type EL device.

Hereinafter, a conventional technology will be described with reference to the accompanying drawings.

1 is a cross-sectional view for explaining a conventional EL element.

Referring to FIG. 1, a conventional EL device forms a transparent electrode 110 made of a transparent conductive material such as ITO on a transparent insulating substrate 100, and emits a light emitting layer 120 and a dielectric layer on the transparent electrode 110. After forming the insulating layer 130 and the back electrode layer 140 to be used as, the protective layer 150 formed to surround the light emitting layer 120, the insulating layer 130 and the back electrode layer 140 is formed.

In the conventional EL device, when driving power is applied using a front terminal electrode connected to the transparent electrode 110 and a back terminal electrode connected to the back electrode 140 as an electrode, light is emitted from the light emitting layer 120. It has a structure that emits light.

However, the EL element as described above generally has a problem of lower luminance than other light sources.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art, and the present invention provides a EL device having improved luminance in a multi-layered light emission form by stacking a plurality of EL elements having the same color and connecting each EL element in parallel. Its purpose is to.

The present invention for achieving the above object is a transparent electrode layer formed on a transparent insulating substrate; A first light emitting layer formed on the transparent electrode layer; A first insulating layer formed on the first light emitting layer; A first back electrode layer formed on the first insulating layer; A second light emitting layer formed on the first back electrode layer; A second insulating layer formed on the second light emitting layer; A second back electrode layer formed on the second insulating layer, wherein the transparent electrode layer and the second back electrode are electrically connected to a first terminal electrode, and the first back electrode is electrically connected to a second terminal electrode. It is characterized by providing an EL element having improved luminance in a multilayered light emitting form.

In an embodiment of the present invention, it is preferable to further include a protective layer formed to surround the first light emitting layer, the first insulating layer, the first back electrode layer, the second light emitting layer, the second insulating layer, the second back electrode layer.

Preferably, the first back electrode layer is made of a transparent conductive material, and the second back electrode layer is preferably made of carbon.

The first light emitting layer and the second light emitting layer may be formed to emit light of the same color.

The present invention also includes a plurality of EL element portions stacked on a transparent insulating substrate, each comprising a transparent electrode layer, a light emitting layer, an insulating layer, and a back electrode layer, and a rear surface of the lower EL element portion among the upper and lower EL element portions adjacent to each other. An electrode layer is a common electrode of the upper and lower EL element portions adjacent to each other serving as a transparent electrode layer of the upper EL element portion, and the plurality of EL element portions have a multi-layered light emission structure having a multi-layered light emission structure in parallel. It is characterized by providing an element.

The common electrode is preferably made of a transparent conductive material.

It is preferable that the back electrode layer of the uppermost EL element portion among the plurality of EL element portions is made of carbon.

The back electrode layer of the uppermost EL element portion and the transparent electrode layer of the lowermost EL element portion of the plurality of EL element portions are connected to the same terminal electrode, and the common electrode layers are respectively connected to different terminal electrodes, so that the plurality of EL element portions are connected in parallel. It is preferable.

It is preferable that the plurality of EL element portions emit light of the same color.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

2 is a cross-sectional view for explaining an EL device having improved luminance in a multilayer light emitting form according to an embodiment of the present invention.

Referring to FIG. 2, the EL device of the present invention forms a transparent electrode layer 210 made of a transparent conductive material such as ITO on the transparent insulating substrate 200, and the first light emitting layer 220 on the transparent electrode layer 210. ) And the first insulating layer 230 are sequentially formed, and the first back electrode layer 240 is formed by printing and drying a transparent conductive ink such as ITO on the first insulating layer 230. A first EL element portion composed of the transparent electrode layer 210, the first light emitting layer 220, the first insulating layer 230, and the first back electrode layer 240 is formed.

After forming the first EL element portion, a second light emitting layer 250 is formed on the first back electrode layer 240 of the first EL element portion, and a second insulating layer 260 is formed on the second light emitting layer 250. ) And a second back electrode layer 270 made of a material such as black carbon on the second insulating layer 260 to form a first back electrode layer 240 and a second light emitting layer. A second EL element portion made up of the 250, the second insulating layer 260, and the second back electrode layer 270 is formed.

Then, the first light emitting layer 220, the first insulating layer 230, the first back electrode layer 240, the second light emitting layer 250, the second insulating layer 260, the second back electrode layer 270 A protective layer 280 is formed to surround and protects the respective EL element portions from moisture penetrating from the external environment.

In this case, since the first back electrode layer 240 of the second EL element portion is made of a transparent conductive material such as ITO, the first back electrode layer 240 plays the same role as the transparent electrode layer 210 of the first EL element portion. That is, in an EL element having a structure having a multi-layered light emitting structure in which a plurality of EL element portions are stacked, it serves as a common electrode of the upper and lower EL element portions adjacent to each other.

In addition, two terminal electrodes connecting the transparent electrode layer 210 and the second back electrode layer 270 to the first terminal electrode and connecting the first back electrode layer 240 to the second terminal electrode are formed. An EL element having an improved luminance having a structure of a multi-layer light emitting state in which the EL element portion and the second EL element portion are connected in parallel is formed.

As the above-described EL element having improved luminance of emitting light has the first EL element portion and the second EL element portion connected in parallel, when the AC power is applied to the first terminal electrode and the second terminal electrode, The same voltage is applied to one EL element portion and the second EL element portion. Therefore, when power is applied to the first terminal electrode and the second terminal electrode of the EL element having improved brightness, the first light emitting layer 220 of the first EL element portion and the second light emitting layer 250 of the second EL element portion are applied. Light of the same luminance emits light at the same time, and thus the luminance of light emission is improved as compared with the conventional EL element.

Further, when the first light emitting layer 220 and the second light emitting layer 250 of the second EL element portion are formed to emit light of the same color, the second light emitting layer 250 of the second EL element portion is formed. Although the emitted light is reduced in brightness by the first insulating layer 230 and the first light emitting layer 220 of the first EL element portion, at least 30% of the light emitted from the second light emitting layer 250 is emitted to the outside. As a result, the luminescence brightness is improved by 30% or more compared with the EL element using the conventional single light emitting layer.

In the embodiment of the present invention, the first EL element portion and the second EL element portion have been described using an EL element having an improved luminance having a multi-layered light emitting structure in parallel, but a plurality of EL element portions are stacked and connected in parallel to the luminance. It is also possible to use an EL element having an improved luminance having a structure of an improved multilayer light emitting form.

At this time, in the EL device having a multi-layered light emitting structure having a structure in which the plurality of EL element portions are stacked, the EL element portions each include a transparent electrode layer, a light emitting layer, an insulating layer, and a back electrode layer, and are adjacent to each other. The back electrode layer of the lower EL element portion among the upper and lower EL element portions is a common electrode of the adjacent upper and lower EL element portions serving as transparent electrode layers of the upper EL element portion, and the plurality of EL element portions are connected in parallel. desirable.

It is preferable that the common electrode, that is, the back electrode layer of the remaining EL element portions except the uppermost EL element portion is made of a transparent conductive material formed by printing and drying the transparent conductive ink.

Further, it is preferable that the back electrode layer of the uppermost EL element portion of the plurality of EL element portions is made of carbon.

Further, in order to connect the plurality of EL element portions in parallel, the back electrode layer of the uppermost EL element portion and the transparent electrode layer of the lowermost EL element portion of the plurality of EL element portions are connected to the same terminal electrode, and the rest except for the uppermost EL element portion. The back electrode layer, that is, the common electrode layer, of the EL element portion is connected to different terminal electrodes, respectively.

As described above, according to the present invention, the present invention can provide an EL device having improved luminance having a structure of a multi-layered light emission form by connecting a plurality of EL element units in parallel.

While the foregoing has been described with reference to preferred embodiments of the present invention, those skilled in the art will be able to variously modify and change the present invention without departing from the spirit and scope of the invention as set forth in the claims below. It will be appreciated.

1 is a cross-sectional view for explaining a conventional EL element.

2 is a cross-sectional view for explaining an EL element with improved luminance according to an embodiment of the present invention.

(Explanation of symbols for main parts of drawing)

200; Transparent insulating substrate 210; Transparent electrode layer

220; The first light emitting layer 230; First insulating layer

240; A first back electrode 250; Second emission layer

260; Second insulating layer 270; Second back electrode

280; Protective layer

Claims (10)

A transparent electrode layer formed on the transparent insulating substrate; A first light emitting layer formed on the transparent electrode layer; A first insulating layer formed on the first light emitting layer; A first back electrode layer formed on the first insulating layer; A second light emitting layer formed on the first back electrode layer; A second insulating layer formed on the second light emitting layer; A second back electrode layer formed on the second insulating layer, The transparent electrode layer and the second back electrode layer are electrically connected to the first terminal electrode. And the first back electrode layer is electrically connected to a second terminal electrode. The method of claim 1, The first light emitting layer, the first light emitting layer, the first back electrode layer, the second light emitting layer, the second insulating layer, and the protective layer formed to surround the second back electrode layer further comprises a multi-layer light emitting structure characterized in that the luminance Enhanced EL device. The method of claim 1, And the first back electrode layer is made of a transparent conductive material. The method of claim 1, The second back electrode layer is made of carbon (carbon), EL device having an improved brightness having a multi-layered light emitting structure. The method of claim 1, And the first light emitting layer and the second light emitting layer emit light of the same color. Stacked on a transparent insulating substrate, each comprising a plurality of EL element portions comprising a transparent electrode layer, a light emitting layer, an insulating layer, and a back electrode layer, The back electrode layer of the lower EL element portion among the upper and lower EL element portions adjacent to each other is a common electrode of the upper and lower EL element portions adjacent to each other serving as a transparent electrode layer of the upper EL element portion, And the plurality of EL elements are connected in parallel to each other, and having improved luminance having a multi-layered light emitting structure. The method of claim 6, And the common electrode is made of a transparent conductive material. The method of claim 6, EL device having a multi-layered light emitting structure, wherein the back electrode layer of the uppermost EL element portion of the plurality of EL element portions is made of carbon. The method of claim 6, The back electrode layer of the uppermost EL element portion and the transparent electrode layer of the lowermost EL element portion of the plurality of EL element portions are connected to the same terminal electrode, And the common electrode layers are connected to different terminal electrodes, respectively, so that the plurality of EL element portions are connected in parallel. The method of claim 6, And the plurality of EL element portions emit light of the same color. The EL element having improved luminance having a multi-layered light emitting structure.