Organic electro luminescence device and fabrication method thereof

An organic electro luminescence device includes: a display region and a non-display region defined in first and second substrates, sub-pixels defined in the display region; an array element including at least one TFT in the display region of the first substrate in each sub-pixel; a first electrode in an inner surface of the second substrate; a buffer in a predetermined region to partition an emission region of each sub-pixel on the first electrode, and an electrode separator on the buffer; an insulating layer in the emission region of each sub-pixel, and a spacer formed on the insulating layer; an organic electro luminescent layer in the emission region of each sub-pixel, the emission region including the insulating layer and the spacer; and a second electrode on the second substrate where the organic electro luminescent layer is formed.

This application claims the benefit of Korean Patent Application No. P2004-74059 filed on Sep. 16, 2004, which is hereby incorporated by reference for all purposes as if fully set forth herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an organic electro luminescence device, and more particularly, to a dual panel type organic electro luminescence device and a fabrication method thereof.

2. Description of the Related Art

One of new flat panel display devices is an organic electro luminescence device. Because the organic electro luminescence device is a self-luminous display device, it has a high contrast and wide viewing angle compared to the liquid crystal display (LCD). Also, since the organic electro luminescence device does not require a backlight assembly, it is lightweight and slim. In addition, the organic electro luminescence device can decrease power consumption.

Further, the organic electro luminescence device can be driven at a low DC voltage and has a rapid response time. All the components of the organic electro luminescence device are formed of solid materials; thus, the device is endurable against external impact, can be used in a wide range of temperatures range, and can be manufactured at a low cost.

Specifically, the organic electro luminescence device is easily fabricated through a deposition process and an encapsulation process. Therefore, the fabrication method and apparatus of the organic electro luminescence device is simpler than those of an LCD or plasma display device (PDP).

Such a related art organic electro luminescence device is driven in a passive matrix mode that does not require separate switching elements.

In the passive matrix mode, scan lines and signal lines are crossed with one another and elements are arranged in a matrix. In order to drive pixels, the scan lines are sequentially driven according to time. Therefore, in order to produce a necessary mean brightness, the passive matrix organic electro luminescence device must provide instantaneous brightness corresponding to a product of a mean brightness and the number of lines.

In an active matrix mode, however, a thin film transistor (TFT), serving as a switching element to turn on/off pixel, is disposed in each sub-pixel. A first electrode connected to the TFT is switched on/off based on the sub-pixel, and a second electrode facing the first electrode is a common electrode.

In the active matrix, since a voltage applied to the pixel is charged in a storage capacitor (CST), a voltage must be applied until a next frame signal is input. Therefore, the organic electro luminescence device must be continuously driven during one picture regardless of the number of scan lines.

If the organic electro luminescence device is driven in an active matrix mode, uniform brightness can be obtained even when a low current is applied. Accordingly, the active matrix organic electro luminescence device has advantages of low power consumption, high definition, and large-sized screen.

FIG. 1is a schematic sectional view of a related art bottom emission type organic electro luminescence device. InFIG. 1, only one pixel region including red, green and blue sub-pixels is illustrated for conciseness.

Referring toFIG. 1, first and second substrates10and30are arranged to face each other. Edge portions of the first and second substrates10and30are encapsulated by a seal pattern40. A TFT T is formed on a transparent substrate1of the first substrate10in sub-pixel unit. A first electrode12is connected to the TFT T. An organic electro luminescent layer14is formed on the TFT T and the first electrode12and is arranged to correspond to the first electrode12. The organic electro luminescent layer14contains light emission materials taking on red, green and blue colors. A second electrode16is formed on the organic electro luminescent layer14.

The first and second electrodes12and16function to apply an electric field to the organic electro luminescent layer14.

Due to the seal pattern40, the second electrode16and the second substrate30are spaced apart from each other by a predetermined distance. Therefore, an absorbent (not shown) and a translucent tape (not shown) may be further provided in an inner surface of the second substrate30. The absorbent absorbs moisture introduced from an exterior, and the translucent tape adheres the absorbent to the second substrate30.

In the bottom emission type structure, when the first electrode12and the second electrode16are an anode and a cathode, respectively, the first electrode12is formed of a transparent conductive material and the second electrode16is formed of a metal having a low work function. In such a condition, the organic electro luminescent layer14includes a hole injection layer14a, a hole transporting layer14b, an emission layer14c, and an electron transporting layer14d, which are sequentially formed on a layer contacting with the first electrode12.

The emission layer14chas red, green and blue color filters for sub-pixels.

FIG. 2is an enlarged sectional view of one sub-pixel region in the bottom emission type organic electro luminescence device shown inFIG. 1.

Referring toFIG. 2, a semiconductor layer68, a gate electrode62, and source and drain electrodes80and82are sequentially formed on a transparent substrate1, thereby forming a TFT region. A power electrode72extending from a power line (not shown) is connected to the source electrode80and an organic electro luminescent diode E is connected to the drain electrode82.

A capacitor electrode64is disposed at a lower portion with reference to the power electrode72. The capacitor electrode64is formed of a same material as the semiconductor layer68. A dielectric layer is interposed between the semiconductor layer68and the capacitor electrode64. A region corresponding to them is a storage capacitor region.

Except the organic electro luminescent diode E, the elements formed in the TFT region and the storage capacitor region is an array elements A.

The organic electro luminescent diode E includes a first electrode12, a second electrode16, and an organic electrode luminescent layer14interposed between the first and second electrodes12and16. The organic electro luminescent diode E is disposed in an emission region from which a self-luminous light is emitted.

In the related art organic electro luminescence device, the array element (A) and the organic electro luminescent diode (E) are stacked on the same substrate.

The bottom emission type organic electro luminescence device is fabricated by attaching the substrate, where the array element and the organic electro luminescent diode are formed, to the separate substrate provided for the encapsulation.

In this case, the yield of the organic electro luminescence device is determined by the product of the yield of the array element and the yield of the organic electro luminescent diode. Therefore, the entire process yield is greatly restricted by the process of forming the organic electro luminescent diode. For example, even though excellent array elements are formed, if foreign particles or other factors cause defects in forming the organic electro luminescent layer of a thin film of about 1000 Å thick, the corresponding organic electro luminescence device is defective.

Thus, there are loss of expense and material costs that are spent in fabricating the non-defective array element, resulting in the reduction of the yield.

In addition, the bottom emission type organic electro luminescence device has high stability and a high degree of freedom due to the encapsulation, but has limitation in aperture ratio. Thus, the bottom emission type organic electro luminescence device is difficult to apply to high-definition products. Meanwhile, in the case of the top emission type organic electro luminescence device, the design of the TFTs is easy and the aperture ratio is high. Thus, it is advantageous in view of the lifetime of the product. However, since the cathode is disposed on the organic electro luminescent layer, the selection of material is restricted. Consequently, the transmittance is limited and the luminous efficiency is degraded.

SUMMARY OF THE INVENTION

Accordingly, the present invention is directed to an organic electro luminescence device and a fabrication method thereof that substantially obviate one or more problems due to limitations and disadvantages of the related art.

An advantage of the present invention is to provide an organic electro luminescence device and a fabrication method thereof, capable of improving an aperture ratio and resolution. In the organic electro luminescence device, an array element and an organic electro luminescent diode are formed on different substrates. The organic electro luminescent diode having the organic electro luminescent layer is formed on a second substrate, and a TFT for driving the organic electro luminescent diode is formed on a first substrate. A conductive spacer is formed on the second substrate to electrically connect the TFT and the organic electro luminescent diode.

To achieve these and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, there is provided an organic electro luminescence device, including: a display region and a non-display region defined in first and second substrates, and sub-pixels defined in the display region; an array element including at least one TFT in the display region of the first substrate in each sub-pixel; a first electrode in an inner surface of the second substrate; a buffer in a predetermined region to partition an emission region of each sub-pixel on the first electrode, and an electrode separator on the buffer; an insulating layer in the emission region of each sub-pixel, and a spacer on the insulating layer; an organic electro luminescent layer in the emission region of each sub-pixel, the emission region including the insulating layer and the spacer; and a second electrode on the second substrate where the organic electro luminescent layer is formed.

In another aspect of the present invention, there is provided a fabrication method of an organic electro luminescence device, the fabrication method including: forming an array element including at least one TFT in a display region of a first substrate in each sub-pixel; forming a first electrode in a display region of a second substrate; forming a buffer to partition an emission region of each sub-pixel on the first electrode, and an insulating layer on a predetermined region in the emission region of each sub-pixel; forming an electrode separator in a predetermined region on the buffer and a spacer in a predetermined region on the insulating layer; forming an organic electro luminescent layer in the emission region of each sub-pixel, the emission region including the insulating layer and the spacer; forming a second electrode on the second substrate where the organic electro luminescent layer is formed; and forming a seal pattern at edges of the first and second substrates, and encapsulating the first and second substrates.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 3is a schematic sectional view of a dual panel type organic electro luminescence device.

InFIG. 3, first and second substrates110and130are spaced apart from each other by a predetermined distance. An array element120is formed in an inner surface of a transparent substrate100of the first substrate110and an organic electro luminescent diode E is formed on an inner surface of a transparent substrate101of the second substrate130. Edges of the first and second substrates110and130are encapsulated by a seal pattern140.

The organic electro luminescence device includes a display region and a non-display region. In the display region, the array element and the organic electro luminescent diode are formed so that light is emitted. The non-display region is located outside of the display region.

In the display region, the organic electro luminescent diode E includes a first electrode132used as a common electrode, an electrode separator135disposed at a boundary of the sub-pixels on a top surface of the first electrode132, an organic electro luminescent layer137disposed between electrode separators135, and a second electrode138patterned for each sub-pixel.

A buffer133is formed to partition the organic electro luminescent layer137, that is, to restrict the emission region.

The electrode separator135functions to partition the sub-pixels. As shown inFIG. 3, the electrode separator135is formed on the buffer133in a reversed tapered shape.

Also, in forming the buffer133, an insulating layer134formed of a same material as the buffer133is further provided within the emission region. In forming the electrode separator135on the insulating layer134, a spacer136is further formed of same material as the electrode separator135. For example, the buffer133and the electrode separator135may be formed of an organic material or an inorganic material.

Unlike the electrode separator135, the spacer136may be formed in a tapered shape so that the second electrode138may not be broken by the spacer136. The spacer136is formed to be higher than the electrode separator135.

That is, an outer surface of the spacer135is covered with the organic electro luminescent layer137and the second electrode138in sequence, which will be formed later. Accordingly, the spacer136becomes conductive so that it electrically connects the TFT T of each sub-pixel formed on the first substrate to the second electrode138formed on the second substrate in each sub-pixel.

The organic electro luminescent layer137includes a first carrier transporting layer137a, an emission layer137b, and a second carrier transporting layer137c, which are stacked in sequence. The first and second carrier transporting layers137aand137care used to inject electrons or holes into the emission layer137b, or to transport them.

The first and second carrier transporting layers137aand137care determined by arrangement of anode and cathode electrodes. For example, when the emission layer137bis formed of high molecular compound and the first and second electrodes132and138are respectively configured as anode and cathode electrodes, the first carrier transporting layer137acontacting with the first electrode132has a stacked structure of a hole injection layer and a hole transporting layer, and the second carrier transporting layer137ccontacting with the second electrode138has a stacked structure of an electron injection layer and an electron transporting layer.

Also, the organic electro luminescent layer137can be formed of a high molecular compound or a low molecular compound. When the organic electro luminescent layer137is formed of low molecular compound, it can be formed using a vapor deposition process. Meanwhile, when the organic electro luminescent layer137is formed of high molecular compound, it can be formed using an inkjet process.

An array element120includes TFTs. In order to supply a current to the organic electro luminescent diode E, conductive spacers150are disposed at positions where the second electrode138and the TFTs T are connected in each sub-pixel.

As described above, since the second electrode138covers the outer surface of the spacer136formed on the insulating layer134in the emission region of the second substrate, the spacers150become conductive. Unlike a spacer for a related art LCD, a main object of the conductive spacers150is to electrically connect the two substrates rather than to maintain a cell gap.

That is, the conductive spacer150electrically connects the drain electrode112of the TFT T provided on the first substrate in each sub-pixel and the second electrode138provided on the second substrate130. The conductive spacer150is formed by coating a cylindrical spacer formed of an organic insulating layer with a metal. The conductive spacer150allows pixels of the first and second substrates110and130to be attached in a 1:1 relationship, such that a current can flow therethrough.

In this embodiment, the spacer136is formed in the emission region of the sub-pixel provided on the second substrate, and the outer surface of the spacer136is covered with a high molecular material or a low molecular material used in the organic electro luminescent layer137and material used in the second electrode138. Therefore, the spacer136becomes conductive.

The connection portion of the conductive spacer150and the TFT T will now be described in more detail. A passivation layer124is formed at a region that covers the TFT T. The passivation layer124includes a drain contact hole122to expose a portion of the drain electrode112. An electrical connection pattern114is formed on the passivation layer124such that it is connected to the drain electrode112through the drain contact hole.

Here, the TFT T corresponds to a drive TFT connected to the organic electro luminescent diode E.

The metal for the conductive spacer150is selected from conductive materials, for example, a metal having a ductility and a low specific resistance.

According to an embodiment of the present invention, the organic electro luminescence device is a top emission type that emits light from the organic electro luminescent layer137toward the second substrate130.

The first electrode132is selected from conductive materials having a transmissive property, while the second electrode138is selected from opaque metal materials.

ITO may be used as transmissive material for the first electrode132. Since the ITO has high resistance, an auxiliary electrode131is further formed below the first electrode so as to reduce the resistance of the first electrode.

The auxiliary electrode131can be formed of colored metal having a low specific resistance. As shown, the auxiliary electrode131is formed in a region corresponding to a region where the TFT is formed on the first substrate, that is, below a region where the buffer133is formed.

Also, the separated space I between the first substrate110and the second substrate130can be filled with an inert gas or an insulating liquid.

Although not shown in the drawing, the array element120further includes a scan line, a signal line and a power line crossing over the scan line and spaced apart from each other by a predetermined distance, a switching TFT disposed at an overlapped portion of the scan line and the signal line, and a storage capacitor.

The non-display region of the organic electro luminescence device will be described below. Referring toFIG. 3, the non-display region includes a plurality of dummy sub-pixels formed adjacent to an outermost sub-pixel of the display region, a common electrode connecting part170for receiving a common voltage from the first substrate and transmitting it to the first electrode as the common electrode formed on the second substrate, and a plurality of dummy spacers160formed in a region ranging from the common electrode connecting part170to the seal pattern140.

In the dual panel type organic electro luminescence device, the array element and the organic electro luminescent diode are provided on different substrates. Therefore, unlike the case where the array element and the organic electro luminescent diode are formed on the same substrate, the organic electro luminescent diode is not influenced by the yield of the array element. Thus, the dual panel type organic electro luminescence device can have a good characteristic in terms of the production management of the respective elements.

If a screen is implemented in the top emission under the above-described conditions, the TFTs can be designed without considering aperture ratio, thereby increasing efficiency in array process. Also, products with high aperture ratio and high resolution can be produced. Since the organic electro luminescent diode is formed in a dual panel type, an outer air can be blocked more effectively compared with the related art top emission type, thereby enhancing stability of the product.

In addition, since the TFT and the organic electro luminescent diode are formed on different substrates, a degree of freedom with respect to the arrangement of the TFTs can be sufficiently obtained. Since the first electrode of the organic electro luminescent diode is formed on the transparent substrate, a degree of freedom with respect to the first electrode can be increased compared with the related art structure where the first electrode is formed on the array element.

FIG. 4is a sectional view of a specific region A inFIG. 3. In the dual panel type organic electro luminescence device of the present invention, one sub-pixel region formed in the display region of the second substrate is shown inFIG. 4.

Referring toFIG. 4, the first electrode132is formed on the transparent substrate101of the second substrate130, and the buffer133and the electrode separator135are formed at a boundary of each sub-pixel on the first electrode132.

The buffer133functions to partition the organic electro luminescent layer137, that is, to restrict the emission region. The electrode separator135functions to partition the sub-pixels. As shown inFIG. 4, the electrode separator135is formed on the buffer133and has a reversed tapered shape.

That is, in each sub-pixel, a region between the buffers133is defined as the emission region and this region is formed of a high molecular material or a low molecular material of the organic electro luminescent layer.

In forming the buffer133, an insulating layer134is further formed of a same material as the buffer133. In forming the electrode separator135on the insulating layer134, a spacer136is further formed of the same material as the electrode separator135.

The buffer133and the electrode separator135may be formed of an organic material or an inorganic material. Unlike the electrode separator135, the spacer136is formed to have a tapered shape so that the second electrode138may not be broken by the spacer136. The spacer136is formed to be higher than the electrode separator135.

That is, an outer surface of the spacer136is covered with the organic electro luminescent layer137and the second electrode138in sequence, which will be formed later. Accordingly, the spacer136becomes conductive so that it electrically connects the TFT T of each sub-pixel formed on the first substrate to the second electrode138formed on the second substrate in each sub-pixel.

Since the second electrode138covers the outer surface of the spacer136formed on the insulating layer134in the emission region of the second substrate, the spacers150become conductive. Unlike a spacer for a related art LCD, a main purpose of the conductive spacers114is to electrically connect the two substrates rather than to maintain a cell gap.

That is, the conductive spacer150electrically connects the drain electrode112of the TFT T provided on the first substrate in each sub-pixel and the second electrode138provided on the second substrate130. The conductive spacer150is formed by coating a cylindrical spacer formed of an organic insulating layer with a metal. The conductive spacer150allows pixels of the first and second substrates110and130to be attached in 1:1 correspondence, such that a current can flow therethrough.

In this embodiment, the spacer136is formed in the emission region of the sub-pixel provided on the second substrate, and the outer surface of the spacer136is covered with high molecular material or low molecular material used in the organic electro luminescent layer137and material used in the second electrode138. Therefore, the spacer136becomes conductive.

The organic electro luminescent layer137includes a first carrier transporting layer137a, an emission layer137b, and a second carrier transporting layer137c, which are stacked in sequence. The first and second carrier transporting layers137aand137care used to inject electrons or holes into the emission layer137b, or to transport them.

Also, the organic electro luminescent layer137can be formed of high molecular compound or low molecular compound. When the organic electro luminescent layer137is formed of low molecular compound, it can be formed using a vapor deposition process. Meanwhile, when the organic electro luminescent layer137is formed of high molecular compound, it can be formed using an inkjet process.

Also, the second electrode138formed on the organic electro luminescent layer137is formed to cover the outermost surface of the conductive spacer150. The second electrode138is formed of conductive material, for example, a metal material having a ductility and a low specific resistance.

Since the light from the organic electro luminescent layer137is emitted upward, the first electrode132is formed of one selected from conductive materials having a transmissive property, while the second electrode138is formed of one selected from opaque metal materials.

ITO may be used as transmissive material for the first electrode132. Since the ITO has high resistance, an auxiliary electrode131is further formed below the first electrode so as to reduce the resistance of the first electrode.

The auxiliary electrode131can be formed of colored metal having a low specific resistance. As shown, the auxiliary electrode131is formed in a region corresponding to a region where the TFT is formed on the first substrate, that is, below a region where the buffer133is formed.

FIG. 5is a sectional view of the outer region in the organic electro luminescence device shown inFIG. 3.

Referring toFIG. 5, the non-display region includes a plurality of dummy sub-pixels formed adjacent to the outermost sub-pixel of the display region, a common electrode connecting part170for receiving a common voltage from the first substrate and transmitting it to the first electrode as the common electrode formed on the second substrate, and a plurality of dummy spacers160formed in a region ranging from the common electrode connecting part170to the seal pattern140.

Unlike the sub-pixel formed in the display region of the second substrate, the dummy sub-pixels do not have an insulating layer and a spacer in the emission region, and a TFT is not formed in a corresponding region of the first substrate. Thus, the dummy sub-pixels cannot receive a predetermined signal.

In the common electrode connecting part170, the insulating layer134and the spacer136formed at end portion of the first electrode132are covered with a same metal as the second electrode138. Therefore, the common electrode connecting part170is electrically connected to the electrode pad180formed on one side of the first substrate.

The first electrode132serves as a common electrode and a voltage must always be applied to the first electrode132. As shown inFIG. 5, the common voltage is applied through the electrode pad180to the first electrode132.

That is, the voltage applied from the electrode pad180is applied to the first electrode132through the common electrode connecting part170formed at the end portion of the first electrode132.

Also, regarding the display region, the conductive spacer (150inFIG. 4) is formed separately in each sub-pixel and functions to form a constant gap. A glass fiber is provided inside the seal pattern140formed at the edges of the two substrates, so that a predetermined gap is maintained. However, in the large-sized organic electro luminescence device, it is difficult to constantly maintain the gap between the first and second substrates.

In order to solve this problem, a plurality of dummy spacers160are provided in a region ranging from the common electrode connecting part170to the seal pattern140. Using this structure, the gap between the first and second substrates can be maintained almost similar to the inside of the display region.

That is, in the large-sized organic electro luminescence device, the display failure occurring in the related art can be prevented.

At this time, in forming the insulating layer and the spacer in the display region, the dummy spacer160is formed on a predetermined portion of the second substrate, where the first electrode is not formed.

FIGS. 6A to 6Fare sectional views illustrating a fabrication method of an organic electro luminescence device according to an embodiment of the present invention, focusing on the section view ofFIG. 3.

InFIG. 6A, the array element120is formed in the display region of the first substrate.

For example, when the TFT for the array element120is a polysilicon TFT, the method for forming the array element120includes: forming a buffer layer on the transparent substrate100; forming a semiconductor layer and a capacitor electrode on the buffer layer; forming a gate electrode, and source and drain electrodes on the semiconductor layer; and forming a power electrode on the capacitor electrode, the power electrode being connected to the source electrode.

Then, the electrical connection pattern114is formed to be electrically connected to the drain electrode112of the drive TFT of the array element120.

The connection portion of the electrical connection pattern114and the drive TFT T will now be described in more detail. The passivation layer124is formed at a region that covers the TFT T. The passivation layer124has the drain contact hole to expose a portion of the drain electrode112. The electrical connection pattern114is formed on the passivation layer124such that it is connected to the drain electrode112through the drain contact hole. The electrical connection pattern114comes in contact with the conductive spacer, which will be formed on the second substrate. Consequently, it functions to electrically connect the first substrate and the second substrate.

The electrical connection pattern114and the drain electrode112can be formed in one body.

Also, in forming the electrical connection pattern114, the electrical pad180is formed of same metal as the electrical connection pattern114.

InFIG. 6B, the first electrode132of the organic electro luminescent diode is formed on the transparent substrate101of the second substrate.

The first electrode132may be formed of a transparent conductive material such as indium tin oxide (ITO).

Since the ITO has high resistance, an auxiliary electrode131is further formed below the first electrode so as to reduce the resistance of the first electrode.

The auxiliary electrode131can be formed of colored metal having a low specific resistance. As shown, the auxiliary electrode131is formed in a region corresponding to a region where the TFT is formed on the first substrate, that is, below a region where the buffer133is formed.

InFIG. 6C, in the display region, the buffer133for partitioning the sub-pixels is formed at a predetermined region on the first electrode, that is, an outer region of the sub-pixel. The electrode separator135is formed on the region where the buffer133is formed. The insulating layer134is formed of a same material as the buffer133. The spacer136is formed of the same material as the electrode separator136.

The buffer133functions to partition the organic electro luminescent layer formed inside the sub-pixel, that is, to restrict the emission region, and the electrode separator135functions to separate the adjacent sub-pixels. As shown inFIG. 6C, the electrode separator135is formed to have a reversed tapered shape.

On the contrary, the spacer136is formed to have a in a tapered shape so that the second electrode may not be broken by the spacer136. The spacer136is formed to be higher than the electrode separator135.

Also, in the non-display region, the insulating layer134and the spacer136forming the common electrode connecting part are formed at the end portion of the first electrode132. The insulating layer134and the spacer136are also formed in a region of the second substrate, where the first electrode is not formed. In this manner, the dummy spacer160is formed.

InFIG. 6D, the organic electro luminescent layer137is formed in a region defined by the buffer133in each sub-pixel.

The organic electro luminescent layer137is formed of high molecular material or low molecular material. When the first and second electrodes are the anode and the cathode, respectively, the organic electro luminescent layer137includes the hole transporting layer137a, the emission layer137b, and the electron transporting layer137c, which are stacked in sequence. The hole/electron transporting layers137aand137care used to inject holes or electrons into the emission layer137b, and to transport them.

The hole transporting layer137acontacting with the first electrode132has a stacked structure of a hole injection layer and a hole transporting layer, and the electron transporting layer137ccontacting with the second electrode138has a stacked structure of an electron injection layer and an electron transporting layer.

InFIG. 6E, after the organic electro luminescent layer137is formed between the buffers133, the second electrode138of the organic electro luminescent diode is formed on the organic electro luminescent layer137.

Since the second electrode138is divided according to the sub-pixel, it serves as the pixel electrode.

In this manner, the organic electro luminescent layer137and the second electrode138are formed to cover the outer surface of the spacer136provided in the emission region.

Consequently, since the spacer136becomes conductive, the TFT formed on the first substrate and the second electrode formed on the second substrate are electrically connected by the spacer136.

The conductive spacer150is formed to cover the second electrode138in the outer surface of the spacer136formed on the insulating layer134of the emission region. Unlike the spacer for the related art LCD, the conductive spacer150electrically connects the two substrates rather than to maintain a cell gap.

That is, the conductive spacer150electrically connects the drain electrode112of the TFT T provided on the first substrate in each sub-pixel and the second electrode138provided on the second substrate130. The conductive spacer150is formed by coating a cylindrical spacer formed of a same organic insulating layer as the electrode separator with a metal, that is, the second electrode. The conductive spacer150allows pixels of the first and second substrates110and130to be attached in 1:1 relationship, such that a current can flow therethrough.

Also, the second electrode138is formed to cover the insulating layer134and the spacer136formed at the end portion of the first electrode in the non-display region. The second electrode138comes in contact with the electrode pad180, thereby forming the common electrode connecting part170.

InFIG. 6F, the first and second substrates110and130are attached to each other and encapsulated. Due to the attachment of the electrical connection pattern114of the first substrate110and the conductive spacer150of the second substrate130, the first and second substrates110and130are electrically connected to each other. Consequently, the second electrode138of the organic electro luminescent diode formed on the second substrate130is electrically connected to the drain electrode112of the drive TFT formed on the first substrate110.

According to the present invention, production yield and production management efficiency can be enhanced. Since the organic electro luminescence device is a top emission type, the design of the TFTs becomes easy and high aperture ratio and high resolution can be provided. Also, since the electrode for the organic electro luminescence diode is formed on the substrate, various materials can be used. In addition, since the organic electro luminescence device is a top emission type and has an encapsulation structure, reliable products can be provided.

Further, the gap between the first and second substrates can be maintained almost similar to the inside of the array region by forming dummy spacers in the region ranging from the outside of the array region to the seal pattern.