KR20080082233A - Organic light emitting display device and method for fabricating the same - Google Patents

Abstract

An organic light emitting display device and a method for fabricating the same are provided to implement various gray-scale images by connecting a first light emitting diode to a thin film transistor and a single gray-scale image by applying a uniform voltage to an anode and a cathode through a second light emitting diode. An organic light emitting display device includes a first substrate(200), a thin film transistor(210,220,230a,230b), a first light emitting diode, a second substrate(270), and a second light emitting diode. The thin film transistor is positioned on the first substrate. The first light emitting diode is electrically connected to the thin film transistor. The second substrate faces the first substrate. The second light emitting diode is positioned on the second substrate. The first and second light emitting diodes include first electrodes(245,275), light emitting layers(260,290), and second electrodes(265,300) respectively and are electrically connected to each other.

Description

Organic Light Emitting Display Device And Method for fabricating the same

1 is a cross-sectional view of an organic light emitting display device according to an embodiment of the present invention.

2A through 2D are cross-sectional views illustrating processes of manufacturing an organic light emitting display device according to an embodiment of the present invention.

Explanation of symbols on the main parts of the drawings

200: first substrate 205: buffer layer

210: gate electrode 215: gate insulating film

220: semiconductor layer 225: interlayer insulating film

230a, 230b: source / drain electrodes

235: passivation film 245: first anode

250: first bank layer 260: first light emitting layer

265: first cathode 270: second substrate

275: second anode 280: second bank layer

290: second light emitting layer 300: second cathode

The present invention relates to an organic light emitting display device and a method of manufacturing the same.

Among flat panel display devices, an organic light emitting display device is a self-luminous display device that electrically excites an organic compound to emit light. The organic light emitting display device does not need a backlight used in the LCD, so it is not only lightweight but also simplifies the process. In addition, low-temperature fabrication is possible, response speed is 1ms or less, high speed response speed, low power consumption, wide viewing angle, high contrast and the like.

The organic light emitting display device includes an organic light emitting layer between the anode and the cathode, and holes supplied from the anode and electrons received from the cathode combine in the organic light emitting layer to form an exciton, which is a hole-electron pair, and then the exciton is in a ground state. The light emitted by the energy generated by returning to.

The conventional organic light emitting display device is manufactured by forming thin film transistors on a substrate, forming a light emitting diode electrically connected to the thin film transistors, and then sealing the substrate and the encapsulation substrate.

However, such a conventional organic light emitting display device can only implement one of a top emission type or a bottom emission type on a single substrate. Since the two separately manufactured panels must be coupled to each other by abutting structure between the shield caps, the thickness of the display device is very thick.

As described above, the conventional organic light emitting display device has a problem in that it is subject to many limitations in terms of application of products to meet the needs of consumers due to problems that are contrary to product trends aiming at light and small size.

Accordingly, the present invention provides an organic light emitting display device and a method of manufacturing the same, which can emit light on both sides with one driving unit, and can realize light and small size reduction.

In order to achieve the above object, the present invention provides a first substrate, a thin film transistor positioned on the first substrate, a first light emitting diode electrically connected to the thin film transistor, and a second substrate facing the first substrate. And a second light emitting diode and the first and second light emitting diodes disposed on the second substrate each include a first electrode, a light emitting layer, and a second electrode, and the first and second light emitting diodes are electrically connected to each other. An organic light emitting display device is provided.

The present invention also provides a method of forming a thin film transistor on a first substrate, forming a first light emitting diode electrically connected to the thin film transistor, the first light emitting diode including a first electrode, a light emitting layer, and a second electrode. Preparing a second substrate facing the first substrate, forming a second light emitting diode including a first electrode, a light emitting layer, and a second electrode on the second substrate, wherein the first and second light emitting diodes are electrically And bonding the first and second substrates to be connected to each other.

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

<Example>

1 is a cross-sectional view illustrating an organic light emitting display device according to an embodiment of the present invention.

Referring to FIG. 1, a buffer layer 205 is positioned on a first substrate 200 made of glass, plastic, or metal, and a gate electrode 210 is positioned on the buffer layer 205.

The gate insulating layer 215 is positioned on the first substrate 200 including the gate electrode 210. The semiconductor layer 220 is positioned on the gate insulating layer 215 such that the gate electrode 210 and a predetermined region correspond to each other, and source and drain electrodes 230a and 230b are positioned on the predetermined region of the semiconductor layer 220. do.

The passivation layer 235 is positioned on the first substrate 200 including the source and drain electrodes 230a and 230b. The passivation film 235 is formed to expose the via hole 240.

The first anode 245 is positioned on the first substrate 200 including the passivation layer 235. The first anode 245 is electrically connected to the drain electrode 230b through the via hole 240.

The first bank layer 250 is positioned on the first substrate 200 including the first anode 245. The first bank layer 250 includes a first opening 255 exposing a portion of the first anode 245.

The first emission layer 260 is positioned in the first opening 255 of the first bank layer 250. The first emission layer 260 may include an organic material, and alternatively, may be an inorganic material. In addition, a first cathode 265 is positioned on the first light emitting layer 260. Accordingly, the first anode 245, the first light emitting layer 260, and the first cathode 265 constitute a first light emitting diode.

The second anode 275 is positioned on the second substrate 270 opposite to the first substrate 200. The second anode 275 may be a common electrode formed on the entire surface of the second substrate 270.

Alternatively, the second anode 275 may be patterned for each subpixel. In this case, although not shown, wirings for selectively turning on / off a part of the second anode 275 may be connected.

The second bank layer 280 is positioned on the second substrate 270 including the second anode 275. The second bank layer 280 includes a second opening 285 exposing a portion of the second anode 275.

The second emission layer 290 is positioned in the second opening 285 of the second bank layer 280. The contact spacer 295 is positioned on the second bank layer 280 spaced apart from the second opening 285.

The second cathode 300 is positioned on the contact spacer 295 and the second emission layer 290. Accordingly, the second anode 275, the organic emission layer 290, and the second cathode 300 constitute a second light emitting diode.

The first substrate 200 on which the first light emitting diode is formed and the second substrate 270 on which the second light emitting diode are formed are bonded by the sealant 305, and the first cathode 265 of the first light emitting diode is formed. ) And the second cathode 300 of the second light emitting diode are electrically connected to each other through the contact spacer 295.

Therefore, the organic light emitting display device of the present invention having the structure as described above includes a bottom light emitting diode formed on the first substrate and a top light emitting diode formed on the second substrate, so that the same current is applied to one driving unit so that both sides There are advantages in that light emission can be realized and light weight can be realized.

In addition, since the first light emitting diode is connected to the thin film transistor, an image of various gray levels can be implemented according to a signal applied to the thin film transistor, and the second light emitting diode is applied by applying a constant voltage to the anode and the cathode, which are common electrodes, and the like. By using or by turning on / off specific second anodes patterned in subpixel units, a single gray scale image may be implemented.

Therefore, the organic light emitting display device according to an embodiment of the present invention has an advantage that can be applied to a mobile communication device such as a folding cell phone.

Hereinafter, a method of manufacturing an organic light emitting display device according to an embodiment of the present invention having the above structure will be described with reference to FIGS. 2A to 2D.

2A through 2D are cross-sectional views illustrating processes of manufacturing an organic light emitting display device according to an exemplary embodiment of the present invention.

Referring to FIG. 2A, a buffer layer 405 is formed on a first substrate 400 made of glass, plastic, or metal. The buffer layer 405 is to be formed to protect the thin film transistor formed in a subsequent process from impurities such as alkali ions leaked from the first substrate 400, such as silicon oxide (SiO _2), silicon nitride (SiNx) To form selectively.

Subsequently, a first conductive layer is stacked on the buffer layer 405. The first conductive layer may be formed of one selected from the group consisting of aluminum (Al), aluminum alloy (Al alloy), molybdenum (Mo), molybdenum alloy (Mo alloy), tungsten (W), and tungsten silicide (WSi ₂ ). desirable. Then, the first conductive layer is patterned to form the gate electrode 410.

Subsequently, a gate insulating film 415 is stacked on the first substrate 400. The gate insulating film 415 may be formed of a silicon oxide film, a silicon nitride film, or a double layer thereof.

Next, an amorphous silicon layer or a polycrystalline silicon layer is laminated on the gate insulating film 415. Next, the semiconductor layer 420 is formed to pattern the gate electrode 410 to correspond to a predetermined region. Although not shown, an ohmic contact layer may be disposed on the semiconductor layer 420.

Subsequently, a second conductive layer is laminated on the first substrate 400 including the semiconductor layer 420. Here, the second conductive layer is formed of a low resistance material in order to lower the wiring resistance, and is formed of a multilayer film made of molybdenum tungsten (MoW), titanium (Ti), aluminum (Al), or aluminum alloy (Al alloy). As the multilayer, a laminated structure of molybdenum tungsten / aluminum molybdenum tungsten (MoW / Al / MoW) may be used. Next, the second conductive layer is patterned to form source and drain electrodes 425a and 425b in a predetermined region of the semiconductor layer 420.

Next, referring to FIG. 2B, a passivation film 430 is stacked on the first substrate 400 including the source and drain electrodes 425a and 425b. Thereafter, the passivation film 430 is etched to form a via hole 435 exposing a portion of the drain electrode 425b.

Subsequently, a third conductive layer is stacked on the passivation layer 430 and the via hole 435 and patterned for each subpixel to form a first anode 440. The first anode 440 may be formed to include a transparent conductive film having a high work function such as indium tin oxide (ITO), indium zinc oxide (IZO), indium cerium oxide (ICO), or zinc oxide (ZnO). . Therefore, the first anode 440 may be a transparent electrode or a transmission electrode.

Subsequently, a first bank layer 445 is stacked on the first anode 440. The first bank layer 445 is then etched to form a first opening 450 that exposes a portion of the first anode 440.

Subsequently, a first emission layer 455 is formed in the first opening 450. Although not shown, a hole injection layer and a hole transport layer may be formed between the first anode 440 and the first light emitting layer 455, and an electron transport layer and an electron injection layer may be formed on the first light emitting layer 455. . The first emission layer 455 may include an organic material, and alternatively, may include an inorganic material.

Subsequently, a first cathode 460 is formed by stacking a fourth conductive layer on the first substrate 400 including the first emission layer 455. The first cathode 460 may be made of magnesium (Mg), silver (Ag), aluminum (Al), calcium (Ca), or an alloy thereof having low wiring resistance and work function. Accordingly, the first cathode 460 may be a reflective electrode and may be formed on the entire surface of the first substrate 400 to serve as a common electrode.

As described above, the thin film transistor including the gate electrode 410, the semiconductor layer 420, and the source / drain electrodes 425a and 425b on the first substrate 400, the first anode 440, and the first emission layer ( A first light emitting diode comprising a 455 and a first cathode 460 is manufactured.

Next, referring to FIG. 2C, a second substrate 470 is prepared. Then, a second anode 475 is formed on the second substrate 470. The second anode 475 may be formed to include a transparent conductive film having a high work function such as indium tin oxide (ITO), indium zinc oxide (IZO), indium cerium oxide (ICO), or zinc oxide (ZnO). Therefore, the second anode 475 may be a transparent electrode or a transmission electrode.

Here, the second anode 475 may be formed on the entire surface of the second substrate 470 to form a common electrode. Alternatively, the second anode 475 may be formed by patterning each subpixel in the same manner as the first anode of the first light emitting diode. In this case, although not shown, wires for applying an electrical signal may be connected to the second anode 475.

Subsequently, a second bank layer 480 is formed on the second anode 475. The second bank layer 480 is then etched to form a second opening 485 that exposes a portion of the second anode 475.

Next, a photoresist is applied on the second bank layer 480, and then exposed and developed to form the contact spacers 490. Here, the contact spacer 490 is formed in consideration of the position so that the contact spacer 490 can be connected to the second electrode of the first light emitting diode when the first substrate 400 and the second substrate 470 are bonded to each other.

In the exemplary embodiment of the present invention, the contact spacer 490 is formed of a photoresist, but is not limited thereto. The contact spacer 490 may be formed of any other usable material.

Next, a second light emitting layer 495 is formed in the second opening 485. Although not shown here, a hole injection layer and a hole transport layer may be formed between the second anode 475 and the second light emitting layer 495, and an electron transport layer and an electron injection layer may be formed on the second light emitting layer 495. have. In addition, like the light emitting layer of the first light emitting diode, it may include an organic material or an inorganic material.

Next, a second cathode 500 is formed by stacking a fifth conductive layer on the second substrate 470 including the contact spacer 490 and the second emission layer 495. The second cathode 500 may be made of magnesium (Mg), silver (Ag), aluminum (Al), calcium (Ca), or an alloy thereof having low wiring resistance and work function. Accordingly, the second cathode 500 may serve as a reflective electrode and may be formed on the entire surface of the second substrate 470 to serve as a common electrode.

As described above, a second light emitting diode including the second anode 475, the second light emitting layer 495, and the second cathode 500 is manufactured.

Subsequently, referring to FIG. 2D, the first substrate 400 and the second substrate 470 manufactured as described above are bonded to each other using the sealant 510. The sealant 510 may be a photocurable resin-based resin which may be cured by irradiating light after bonding. For example, an acrylic resin, an epoxy resin, or a frit may be used. In addition, the second cathode 500 of the second light emitting diode is electrically connected to the first cathode 460 of the first light emitting diode positioned on the first substrate 400 through the contact spacer 490. As a result, as described above, the manufacture of the organic light emitting display device according to the exemplary embodiment of the present invention is completed.

The organic light emitting display device according to the embodiment of the present invention manufactured as described above is provided with a driving unit made of a thin film transistor on the first substrate and a first light emitting diode emitting light to the rear surface, and a first light emitting diode emitting light on the front surface of the second substrate. 2 light emitting diodes are provided. The substrates are coupled to each other to electrically connect the second cathode of the second LED and the first cathode of the first LED. Therefore, unlike the conventional two-sided light emitting by attaching each panel emitting light in one direction, there is an advantage that can realize a light weight and thinning by implementing the two-sided light emitting in one panel.

In addition, the first light emitting diode of the organic light emitting display device according to an exemplary embodiment of the present invention may be connected to a thin film transistor and receive a signal therefrom to display images of various gray levels. In addition, the second light emitting diode may be used for lighting or the like by applying a predetermined voltage to the second anode and the second cathode, which are common electrodes, or the second light emitting diode may have a second cathode of the first cathode of the first light emitting diode. By selectively turning on / off the second anode connected to and patterned for each subpixel, a single gray scale image can be displayed.

Accordingly, the organic light emitting display device according to an embodiment of the present invention can represent a different image of each of the first light emitting diode and the second light emitting diode, and thus, the organic light emitting display device can be used in a mobile communication device such as a cellular phone.

In the present invention, the electrode of the first light emitting diode connected to the thin film transistor is named as the first anode, but is not limited thereto, and the position of the cathode and the anode may be changed. In addition, in the case of the second light emitting diode formed on the second substrate, the positions of the anode and the cathode may also be changed.

Although the embodiments of the present invention have been described above with reference to the accompanying drawings, the technical configuration of the present invention described above may be modified in other specific forms by those skilled in the art to which the present invention pertains without changing its technical spirit or essential features. It will be appreciated that it may be practiced. Therefore, the embodiments described above are to be understood as illustrative and not restrictive in all aspects. In addition, the scope of the present invention is shown by the claims below, rather than the above detailed description. Also, it is to be construed that all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts are included in the scope of the present invention.

As described above, the organic light emitting display device and the manufacturing method thereof according to the present invention have an advantage of realizing a light weight thin film and double-sided light emission.

Claims (16)

A first substrate; A thin film transistor positioned on the first substrate; A first light emitting diode electrically connected to the thin film transistor; A second substrate facing the first substrate; And A second light emitting diode positioned on the second substrate; The first and second light emitting diodes each include a first electrode, a light emitting layer, and a second electrode, And the first and second light emitting diodes are electrically connected to each other. The method of claim 1, And a contact spacer on the second substrate, the contact spacer electrically connected to the second electrode of the second light emitting diode. The method of claim 2, And the second electrode of the second light emitting diode is connected to the second electrode of the first light emitting diode by the contact spacer. The method of claim 1, The organic light emitting display device of claim 1, wherein the first electrodes of the first and second light emitting diodes are transmissive electrodes. The method of claim 1, And the second electrodes of the first and second light emitting diodes are reflective electrodes. The method of claim 1, An organic light emitting display device, wherein the first electrodes of the first and second light emitting diodes are patterned for each subpixel. The method of claim 1, And a second electrode of the first and second light emitting diodes is a common electrode. The method of claim 1, The first substrate and the second substrate are bonded to each other by a sealant. The method of claim 1, And the light emitting layer comprises an organic material. The method of claim 1, The first light emitting diode displays an image of various gradations, and the second light emitting diode displays an image having one gradation. Forming a thin film transistor on the first substrate; Forming a first light emitting diode electrically connected to the thin film transistor, the first light emitting diode including a first electrode, a light emitting layer, and a second electrode; Preparing a second substrate facing the first substrate; Forming a second light emitting diode comprising a first electrode, a light emitting layer, and a second electrode on the second substrate; And bonding the first and second substrates such that the first and second light emitting diodes are electrically connected to each other. The method of claim 11, And forming a contact spacer electrically connected to the second electrode of the second light emitting diode on the second substrate. The method of claim 12, The second electrode of the second light emitting diode is connected to the second electrode of the first light emitting diode by the contact spacer. The method of claim 11, The method of manufacturing an organic light emitting display device, characterized in that the first electrodes of the first and second light emitting diodes are patterned for each sub-pixel. The method of claim 11, A method of manufacturing an organic light emitting display device, characterized in that the second electrodes of the first and second light emitting diodes are common electrodes. The method of claim 11, The light emitting layer is a method of manufacturing an organic light emitting display device, characterized in that it comprises an organic material.

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