KR20150001068A - Organic Light Emitting Diod Display - Google Patents

Abstract

The present invention relates to a large organic light emitting display device which ensures uniform luminance distribution over the entire display area. According to the present invention, the organic light emitting display device includes: a substrate including a display area which has a plurality of defined pixel areas arranged in a matrix, and a non-display area arranged around the display area; a first electrode formed in each of the pixel area shaped like an island; a secondary cathode electrode spaced apart from the first electrode, and arranged to occupy the entire part of the display area; an organic light emitting layer laminated on the first electrode; and a second electrode coated on the entire display area to face the first electrode on the organic light emitting layer and comes in contact with the secondary cathode electrode.

Description

[0001] The present invention relates to an organic light emitting diode display,

The present invention relates to an organic light emitting display device having a uniform luminance distribution over the entire display area. Particularly, the present invention relates to an organic light emitting display device having a constant luminance over a whole surface of a display panel, in particular, over a whole surface of a large-area display panel such as a large TV, by lowering the surface resistance of the cathode electrode applied over the entire surface of the substrate will be.

2. Description of the Related Art Recently, various flat panel display devices capable of reducing weight and volume, which are disadvantages of cathode ray tubes (CRTs), have been developed. Such flat panel display devices include a liquid crystal display (LCD), a field emission display (FED), a plasma display panel (PDP), and an electro-luminescence device (EL) .

1 is a plan view showing the structure of an organic light emitting diode display (OLED) using a thin film transistor which is an active device according to the related art. FIG. 2 is a cross-sectional view cut along the cutting line II-II 'in FIG. 1, showing a structure of a conventional organic light emitting display device.

1 and 2, an organic light emitting display includes a thin film transistor (TFT) substrate having a thin film transistor (ST) and a thin film transistor (DT) and an organic light emitting diode (OLED) And a cap (ENC) which opposes and bonds the organic bonding layer (POLY) therebetween. The thin film transistor substrate includes a switching TFT ST, a driving TFT DT connected to the switching TFT ST, and an organic light emitting diode OLED connected to the driving TFT DT.

On the glass substrate SUB, the switching TFT ST is formed at a position where the gate line GL and the data line DL cross each other. The switching TFT ST functions to select a pixel. The switching TFT ST includes a gate electrode SG, a semiconductor layer SA, a source electrode SS and a drain electrode SD which branch off from the gate line GL. The driving TFT DT serves to drive the anode electrode ANO of the pixel selected by the switching TFT ST. The driving TFT DT includes a gate electrode DG connected to the drain electrode SD of the switching TFT ST, a source electrode DS connected to the semiconductor layer DA, the driving current transfer wiring VDD, (DD). The drain electrode DD of the driving TFT DT is connected to the anode electrode ANO of the organic light emitting diode.

In FIG. 2, a thin film transistor having a top gate structure is shown as an example. In this case, the semiconductor layer DA of the switching TFT ST and the semiconductor layer DA of the driving TFT DT are formed first on the substrate SUB, and the gate electrodes G1 and G2 are formed on the gate insulating film GI, SG, and DG are formed overlapping the center portions of the semiconductor layers SA and DA. Source electrodes SS and DS and drain electrodes SD and DD are connected to both sides of the semiconductor layers SA and DA through a contact hole. The source electrodes SS and DS and the drain electrodes SD and DD are formed on the insulating film IN covering the gate electrodes SG and DG.

A gate pad GP formed at one end of each gate line GL and a data pad DP formed at one end of each data line DL are formed in the outer periphery of the display region where the pixel region is disposed, A driving current pad VDP formed at one end of the current transfer wiring VDD is disposed. The protective film PAS is entirely coated on the substrate SUB on which the switching TFT ST and the driving TFT DT are formed. Contact holes exposing the gate pad GP, the data pad DP, the driving current pad VDP, and the drain electrode DD of the driving TFT DT are formed. Then, a flattening film PL is applied onto the display area of the substrate SUB. The planarization layer PL serves to uniformize the roughness of the substrate surface in order to apply the organic material constituting the organic light emitting diode in a smooth planar state.

An anode electrode ANO is formed on the planarizing film PL in contact with the drain electrode DD of the driving TFT DT through the contact hole. The gate pad GP, the data pad DP, and the gate formed on the driving current pad VDP, which are exposed through the contact holes formed in the passivation film PAS, are formed on the outer peripheral portion of the display region where the planarization film PL is not formed. A pad terminal GPT, a data pad terminal DPT, and a driving current pad terminal VDPT, respectively. The bank BA is formed on the substrate SUB except for the pixel region in the display region. A spacer SP is further formed on a part of the bank BA.

The encapsulation (ENC) is attached on the thin film transistor substrate having the above-described structure while keeping the spacers SP therebetween at regular intervals. In this case, it is preferable that the thin film transistor substrate and the cap (ENC) are completely sealed together by interposing an organic bonding layer (POLY) therebetween. The gate pad GP and the gate pad terminal GPT and the data pad DP and the data pad terminal DPT are exposed to the outside of the cap ENC and connected to an external device through various connecting means.

In an organic light emitting display having such a structure, a cathode electrode having a basic voltage is applied over the entire surface of the substrate of the display panel. When the cathode electrode is formed of a metal material having a low specific resistance value, there is no serious problem. However, when the cathode electrode is formed of a transparent conductive material in order to secure the transmittance, the surface resistance may become large and the image quality may be deteriorated.

For example, when the cathode electrode contains indium-tin oxide or indium-zinc oxide, which is a transparent conductive material or a material having a higher resistivity than metal, the surface resistance becomes large. Then, there arises a problem that the cathode electrode does not have a constant voltage value over the entire area of the display panel. In particular, when the organic electroluminescent display device is developed as a large area organic electroluminescent display device, the phenomenon that the brightness of the display device becomes uneven over the entire screen may become more important.

SUMMARY OF THE INVENTION An object of the present invention is to provide an organic electroluminescent display device which is distributed in such a manner as to have a uniform value across a display area without any difference in base voltage. Another object of the present invention is to provide an organic electroluminescent display device further comprising an auxiliary cathode electrode corresponding to a substrate area so as to maintain a low surface resistance over the entire area of the cathode electrode. It is still another object of the present invention to provide an organic light emitting display device including an auxiliary cathode electrode electrically connected to a cathode electrode through a contact point having a short contact distance with the cathode electrode.

In order to achieve the above object, an organic light emitting display according to the present invention includes: a substrate having a display region defined by a plurality of pixel regions arranged in a matrix manner; and a non-display region disposed around the display region; A first electrode formed in an island shape in each pixel region; An auxiliary cathode electrode spaced apart from the first electrode by a predetermined distance and disposed over the entire display region; An organic light emitting layer stacked on the first electrode; And a second electrode formed on the organic light emitting layer so as to cover the entire display area opposite to the first electrode and in contact with the auxiliary cathode electrode.

A thin film transistor formed in each of the pixel regions on the substrate; A planarization layer covering the thin film transistor and having the first electrode and the auxiliary cathode electrode formed on an upper surface thereof; And a bank having a light emitting region for covering a part of the first electrode and a cathode contact hole for exposing a part of the auxiliary cathode electrode, the organic light emitting layer being applied to the light emitting region, A second electrode is applied on the bank and is in contact with the organic light emitting layer formed in the light emitting region and in contact with the second electrode through the cathode contact hole.

The non-display region includes a base wiring disposed in an outermost portion of the substrate in the non-display region, the auxiliary cathode electrode extending to the non-display region and contacting the base wiring, And a first cathode contact hole exposing a part of the formed auxiliary cathode electrode.

And a base line disposed at an outermost portion of the substrate in the non-display region, wherein the auxiliary cathode electrode extends to the non-display region and contacts the base line, and the cathode contact hole is formed in the pixel region And a second cathode contact hole exposing a part of the auxiliary cathode electrode.

The non-display region includes a base wiring disposed in an outermost portion of the substrate in the non-display region, the auxiliary cathode electrode extending to the non-display region and contacting the base wiring, A first cathode contact hole exposing a part of the auxiliary cathode electrode and a second cathode contact hole exposing a part of the auxiliary cathode electrode formed in the pixel region.

Also, an organic light emitting display device according to the present invention includes: a substrate defining a plurality of pixel regions arranged in a matrix manner; A thin film transistor formed in each pixel region; A first electrode connected to the thin film transistor and formed in a part of the pixel region; An auxiliary cathode electrode spaced apart from the first electrode and formed in a remaining region of the pixel region surrounding the first electrode; A bank having a light emitting region for exposing a part of the first electrode and a first cathode contact hole for exposing a part of the auxiliary cathode electrode; An organic light emitting layer formed in the light emitting region; And a second electrode which is applied over the entire pixel region on the bank, is in contact with the organic light emitting layer, and contacts the auxiliary cathode electrode through the first cathode contact hole.

The substrate includes a non-display region disposed in the periphery of the pixel region; And a base wiring disposed in the non-display region, wherein the auxiliary cathode electrode extends to the non-display region and is in contact with the base wiring.

The bank further includes a second cathode contact hole extended to the non-display region and exposed to a part of the auxiliary cathode electrode formed in the non-display region, and the second electrode includes the second cathode contact hole And the cathode electrode is in contact with the auxiliary cathode electrode.

The organic light emitting display device according to the present invention is characterized in that when forming the anode electrode including a metal material such as silver or aluminum having a low specific resistance value, the organic light emitting display device is disposed at a distance from the anode electrode, Is formed. Thereby, the surface resistance of the cathode electrode can be further lowered. Therefore, an organic light emitting display device having uniform brightness over the entire display panel without a difference in brightness distribution can be obtained. In particular, even if the organic electroluminescence display device is manufactured in a large area, the value of the base voltage can be uniformly ensured over the entire area without any deviation.

1 is a plan view showing a structure of an organic light emitting display device using a thin film transistor which is an active device according to the related art.
FIG. 2 is a sectional view cut along the cutting line II-II 'in FIG. 1, showing a structure of a conventional organic light emitting display device.
3 is a plan enlarged view showing a schematic structure of an organic light emitting display device according to a first embodiment of the present invention.
FIG. 4 is a cross-sectional view of the organic light emitting display according to the first embodiment of the present invention, taken along the cutting line I-I 'in FIG. 3;
5 is a plan enlarged view showing a schematic structure of an organic light emitting display device according to a second embodiment of the present invention.
FIG. 6 is a cross-sectional view taken along line II-II 'in FIG. 5, and is a cross-sectional view illustrating the structure of an organic light emitting display device according to a second embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Like reference numerals throughout the specification denote substantially identical components. In the following description, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear. In addition, the component names used in the following description may be selected in consideration of easiness of specification, and may be different from the parts names of actual products.

3 is an enlarged plan view showing a schematic structure of an organic light emitting display according to a first embodiment of the present invention. FIG. 4 is a cross-sectional view of the organic light emitting display according to the first embodiment of the present invention, taken along the cutting line I-I 'in FIG. The first embodiment of the present invention will be described with reference to Figs. 3 and 4. Fig.

First, the structure on a plane will be described with reference to FIG. The organic light emitting display according to the first embodiment of the present invention includes a display area AA for displaying image information and a non-display area NA in which various elements for driving the display area AA are arranged. And a substrate SUB. A plurality of pixel areas PA arranged in a matrix manner are defined in the display area AA. In FIG. 3, the pixel regions PA are indicated by dotted lines.

For example, pixel regions PA can be defined in a rectangle of the NxM system. However, it is not necessarily limited to this method, but may be arranged in various ways. Each of the area areas may have the same size or different sizes. In addition, three sub-pixels representing RGB colors may be regularly arranged as one unit. In the simplest structure, the pixel regions PA include a plurality of gate lines GL extending in the horizontal direction, a plurality of data lines DL and a plurality of driving current lines VDD extending in the vertical direction, .

A data driving unit (DIC) for supplying a signal corresponding to image information to the data lines DL is formed in the non-display area NA defined at the outer periphery of the pixel area PA, A gate driving unit (GIP) for supplying a scan signal to the gate lines GL may be disposed. The data driver DIC is mounted on the outside of the substrate SUB and the data driver DIC is mounted on the outside of the substrate SUB when the number of the data lines DL and the driving current lines VDD increases, Instead, data connection pads may be disposed.

In order to simplify the structure of the display device, the gate driver GIP is preferably formed directly on one side of the substrate SUB. A base wire (Vss) for supplying a base voltage is disposed at the outermost portion of the substrate (SUB). It is preferable that the ground wiring Vss is arranged to receive a ground voltage supplied from the outside of the substrate SUB and to supply a base voltage to both the data driving unit DIC and the gate driving unit GIP. For example, the induced wiring Vss is connected to the data driver DIC disposed on the upper side of the substrate SUB, and the gate driver GIP disposed on the left and / or right side of the substrate SUB As shown in FIG.

In each pixel region PA, organic light emitting diodes (OLEDs), which are core components of the organic light emitting display, and thin film transistors for driving the organic light emitting diodes are disposed. The thin film transistors may be formed in the thin film transistor region TA defined at one side of the pixel region PA. The organic light emitting diode includes an anode electrode (ANO), a cathode electrode (CAT), and an organic light emitting layer interposed between the two electrodes. The region where light is actually emitted is determined by the area of the organic light emitting layer overlapping with the anode electrode ANO.

The anode electrode ANO is formed to occupy a part of the pixel region PA and is connected to the thin film transistor formed in the thin film transistor region TA. The organic light emitting layer is applied on the anode electrode ANO, and the region where the anode electrode ANO and the organic light emitting layer overlap is determined as the actual light emitting region. The cathode electrode CAT is formed by coating on the organic light emitting layer so as to cover at least the area of the display area NA where at least the pixel areas PA are disposed. The cathode electrode CAT receives the base voltage, the anode electrode ANO receives the image voltage, and the organic light emitting layer emits light by the voltage difference therebetween to display the image information.

The cathode electrode (CAT) is formed of a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (ITO). Such a transparent conductive material has a higher resistivity than a metal material. Therefore, when the coating is performed so as to correspond to the entire area of the substrate SUB, the problem of increased surface resistance may arise. Particularly, in the case of a large area organic light emitting display device, the surface resistance value becomes larger. As a result, the base voltage may not be constant over the entire surface of the substrate SUB. For example, if the deviation between the base voltage value at the incoming side side, which is the base voltage applied to the substrate SUB, and the base voltage value at the opposite side farthest from the incoming side, becomes large and the brightness of the screen is not constant have.

In order to prevent this, in the present invention, when forming the anode electrode ANO including a metal material having a low resistivity such as silver (Ag), the auxiliary cathode electrode AC is further formed. For example, the anode electrode ANO is formed in an island shape in the individual pixel region PA. On the other hand, an auxiliary cathode electrode AC is formed which is spaced apart from the anode electrode ANO by a predetermined distance and is connected to the entire display area NA. In particular, the auxiliary cathode electrode AC contacts the base wiring Vss disposed on the outer side of the substrate SUB beyond the gate driving portion GIP. Further, the auxiliary cathode electrode (AC) is electrically connected to the cathode electrode (CAT) formed later on the entire surface of the display area.

More specifically, a conductive layer in which silver and a transparent conductive material are sequentially stacked is applied to the entire substrate SUB and patterned to cover all of the pixel areas PA, Thereby forming an auxiliary cathode electrode AC in contact with the wiring Vss. And an anode electrode ANO having an island shape corresponding to a light emitting region defined in each pixel region PA of the auxiliary cathode electrode AC and connected to the thin film transistor. The anode electrode ANO is isolated from the auxiliary cathode electrode AC by a predetermined distance so as not to be electrically short-circuited to each other.

The cross-sectional structure of the OLED display according to the first embodiment will be described in further detail with reference to FIG. A non-display area NA where a gate driver GIP and a base wire Vss are disposed on a substrate SUB and a switching thin film transistor ST, a driving thin film transistor DT and an organic light emitting diode OLE are formed A display area AA is defined.

The gate driver GIP may include a thin film transistor formed in the process of forming the switching thin film transistor ST and the driving thin film transistor DT. The switching thin film transistor ST formed in the pixel region PA includes a gate electrode SG, a gate insulating film GI, a channel layer SA, a source electrode SS and a drain electrode SD. The driving thin film transistor DT includes a gate electrode DG connected to the drain electrode SD of the switching thin film transistor ST, a gate insulating film GI, a channel layer DA, a source electrode DS and a drain electrode DD).

A protective film PAS and a planarizing film PL are continuously applied on the thin film transistors ST and DT. On the planarizing film PL, an isolated rectangular anode electrode ANO occupying only a certain portion in the pixel region PA is formed. The anode electrode ANO is in contact with the drain electrode DD of the driving thin film transistor DT through the contact hole passing through the protective film PAS and the flattening film PL.

Further, the auxiliary cathode electrode AC is formed with the same material as the anode electrode ANO and spaced apart from the anode electrode ANO by a certain distance. The auxiliary cathode electrode AC has a shape covering at least the pixel area PA on the planarizing film PL. Further, the non-display region NA is formed on the planarizing film PL covering the gate driver GIP so as to be in contact with the base wiring Vss.

The base wiring Vss may be formed on the same layer with the same material as the gate electrode G. [ In this case, it is possible to contact the auxiliary cathode electrode AC through the contact hole penetrating the protective film PAS covering the base wiring Vss. Alternatively, the base wire Vss may be formed on the same layer with the same material as the source-drain (SS-SD, DS-DD) electrode. In this case, the base wiring Vss can contact the auxiliary cathode electrode AC through the contact hole penetrating the protective film PAS and the gate insulating film GI.

A bank BA is applied on the anode electrode ANO and the auxiliary cathode electrode AC. The bank BA is patterned to expose most of the anode electrode ANO. Further, a cathode contact hole CHC exposing a part of the auxiliary cathode electrode AC is formed. The cathode contact hole CHC is preferably formed in the non-display area NA. The organic light emitting layer OL is coated on the anode electrode ANO exposed by the bank BA pattern. On the bank BA, a transparent conductive material is applied to form a cathode electrode (CAT). Thereby, an organic light emitting diode (OLE) including the anode electrode ANO, the organic light emitting layer OL, and the cathode electrode CAT is formed.

Further, the cathode electrode (CAT) is in contact with the auxiliary cathode electrode (AC) through the cathode contact hole (CHC). As a result, the base voltage is transmitted to the auxiliary cathode electrode AC through the base line Vss and then to the cathode electrode CAT. Particularly, in the case of implementing a large area organic light emitting display, even if the area of the cathode electrode (CAT) is increased, by the auxiliary cathode electrode AC having the area corresponding to the area of the cathode electrode (CAT) Since the surface resistance is lowered, the base voltage value can be kept constant over the entire area.

In the first embodiment, the cathode contact holes CHC are formed so as to be disposed in the non-display area NA. In order to allow the low non-resistivity of the auxiliary cathode electrode AC to effectively affect the cathode electrode CAT, the area in which the cathode electrode CAT contacts the auxiliary cathode electrode AC is widened, Lt; / RTI > In the second embodiment, the case where the cathode contact holes are arranged in various ways will be described.

5 is an enlarged plan view showing a schematic structure of an organic light emitting display according to a second embodiment of the present invention. FIG. 6 is a cross-sectional view of the organic light emitting display according to the second embodiment of the present invention, taken along the cutting line II-II 'in FIG.

Referring to Figs. 5 and 6, the second embodiment is basically the same as the first embodiment in the correlation of almost all the components and their components. There is a difference in the arrangement of the cathode contact holes connecting the cathode electrode (CAT) and the auxiliary cathode electrode (AC).

In the second embodiment, a structure for more effectively lowering the surface resistance of the cathode electrode CAT through the auxiliary cathode electrode AC is proposed. Particularly, when a large area organic light emitting display is manufactured, the area of the cathode electrode (CAT) becomes much wider. Accordingly, since the surface resistance of the cathode electrode CAT is further increased, a difference in brightness can be more seriously generated over the entire area of the display device. In order to prevent this, it is necessary to lower the contact resistance at the contact point where the cathode electrode (CAT) and the auxiliary cathode electrode (AC) are in contact with each other. Further, in the case of having a plurality of contact points, it is preferable that the distance to each of the contact points with the auxiliary cathode electrode AC at any arbitrary point of the cathode electrode CAT is uniform. In addition, it is preferable that the connection distance between the cathode electrode CAT and the auxiliary cathode electrode AC is as short as possible.

To this end, the second embodiment further includes a second cathode contact hole (CH2) connecting the cathode electrode (CAT) and the auxiliary cathode electrode (AC) in each of the pixel regions (PA). Here, the difference between the first embodiment and the main components will be mainly described.

The organic light emitting display according to the second embodiment of the present invention includes a display area AA for displaying image information and a non-display area NA in which various elements for driving the display area AA are arranged. And a substrate SUB. A plurality of pixel areas PA arranged in a matrix manner are defined in the display area AA. That is, a non-display area NA where a gate driver GIP and a base wiring Vss are disposed on a substrate SUB, and a switching thin film transistor ST, a driving thin film transistor DT, and an organic light emitting diode OLE A display area AA to be formed is defined.

A data driving unit (DIC) for supplying a signal corresponding to image information to the data lines DL is formed in the non-display area NA defined at the outer periphery of the pixel area PA, A gate driving unit (GIP) for supplying a scan signal to the gate lines GL may be disposed.

In order to simplify the structure of the display device, the gate driver GIP is preferably formed directly on one side of the substrate SUB. A base wire (Vss) for supplying a base voltage is disposed at the outermost portion of the substrate (SUB). The evanescent wiring Vss is connected to the data driver DIC disposed on the upper side of the substrate SUB and surrounds the substrate outside the gate driver GIP disposed on the left and / Can be arranged.

In each pixel region PA, organic light emitting diodes (OLEDs), which are core components of the organic light emitting display, and thin film transistors for driving the organic light emitting diodes are disposed. The thin film transistors may be formed in the thin film transistor region TA defined at one side of the pixel region PA.

The gate driver GIP may include a thin film transistor formed in the process of forming the switching thin film transistor ST and the driving thin film transistor DT. The switching thin film transistor ST formed in the pixel region PA includes a gate electrode SG, a gate insulating film GI, a channel layer SA, a source electrode SS and a drain electrode SD. The driving thin film transistor DT includes a gate electrode DG connected to the drain electrode SD of the switching thin film transistor ST, a gate insulating film GI, a channel layer DA, a source electrode DS and a drain electrode DD).

A protective film PAS and a planarizing film PL are continuously applied on the thin film transistors ST and DT. On the planarizing film PL, an isolated rectangular anode electrode ANO occupying only a certain portion in the pixel region PA is formed. The anode electrode ANO is in contact with the drain electrode DD of the driving thin film transistor DT through the contact hole passing through the protective film PAS and the flattening film PL.

Further, the auxiliary cathode electrode AC is formed with the same material as the anode electrode ANO and spaced apart from the anode electrode ANO by a certain distance. The auxiliary cathode electrode AC has a shape covering at least the pixel area PA on the planarizing film PL. Further, the non-display region NA is formed so as to extend across the upper portion of the planarization film PL covering the gate driver GIP and to be in contact with the base line Vss.

A bank BA is applied on the anode electrode ANO and the auxiliary cathode electrode AC. The bank BA is patterned to expose most of the anode electrode ANO. Further, first and second cathode contact holes CH1 and CH2 exposing a part of the auxiliary cathode electrode AC are formed. The first cathode contact hole CH1 may be formed at the same position as the cathode contact hole CHC described in the first embodiment. For example, the first cathode contact hole CH1 is formed in the non-display area NA to expose one side of the auxiliary cathode electrode AC. Meanwhile, the second cathode contact hole CH2 may be formed to expose a part of the auxiliary cathode electrode AC in each pixel region PA. The second cathode contact hole CH2 is not specifically defined in the area inside each pixel area PA, and the designer can select an appropriate position. Preferably, a position where there are no elements such as a thin film transistor is preferable.

The organic light emitting layer OL is coated on the anode electrode ANO exposed by the bank BA pattern. A transparent conductive material is coated on the bank BA so as to cover the entire pixel area PA to form a cathode electrode CAT. Thereby, an organic light emitting diode (OLE) including the anode electrode ANO, the organic light emitting layer OL, and the cathode electrode CAT is formed.

Further, the cathode electrode CAT is in contact with the auxiliary cathode electrode AC through the first and second cathode contact holes CH1 and CH2. As a result, the base voltage is transmitted to the auxiliary cathode electrode AC through the base line Vss and then to the cathode electrode CAT. That is, since the surface resistance is lowered by the auxiliary cathode electrode AC including the low resistance material and having the area corresponding to the area of the cathode electrode (CAT), the base voltage value can be kept constant over the entire area .

In the drawings for explaining the present invention, the structure of a specific thin film transistor and the structure of an organic light emitting display device have been described. However, a key idea of the present invention is that a low-resistance metal material used for the anode electrode in the process of forming the anode electrode is physically and electrically separated from the anode electrode, and the large-area auxiliary cathode And an electrode was further formed. By electrically connecting the auxiliary cathode electrode to the cathode electrode, the surface resistance of the cathode electrode can be effectively lowered. In particular, in the case of implementing a large area organic light emitting display device, the resistance value of the cathode electrode CAT can be uniformly maintained throughout the display region even if the area of the cathode electrode CAT increases.

Therefore, the flat panel display device to which the present invention is applied has no particular structural limitations. For example, the present invention can be applied not only to organic electroluminescent display devices but also to other flat panel display devices such as electrophoretic display devices. In addition, the structure of the thin film transistor formed in the display device is not limited. That is, the structure is not limited to a bottom gate structure, a top gate structure, or a double gate structure. Also, the organic light emitting display device may be applied to both the bottom emission structure and the top emission structure.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Therefore, the present invention should not be limited to the details described in the detailed description, but should be defined by the claims.

ST: switching TFT DT: driving TFT
SG: switching TFT gate electrode DG: driving TFT gate electrode
SS: switching TFT source electrode DS: driving TFT source electrode
SD: switching TFT drain electrode DD: driving TFT drain electrode
SA: switching TFT semiconductor layer DA: driving TFT semiconductor layer
GL: gate wiring DL: data wiring
VDD: Drive current wiring GP: Gate pad
DP: Data pad GPT: Gate pad terminal
DPT: Data pad terminal VDP: Drive current pad
VDPT: driving current pad terminal GPH: gate pad contact hole
DPH: Data pad contact hole VPH: Drive current pad contact hole
GI: Gate insulating film IN: Insulating film
PAS: protective film PL: planarization film
OL: organic light emitting layer OLED: organic light emitting diode
POLY: organic cohesive membrane ENC: cap
CHC: cathode contact hole AC: auxiliary cathode electrode
CH1: first cathode contact hole CH2: second cathode contact hole

Claims (8)

A substrate having a display region in which a plurality of pixel regions arranged in a matrix manner are defined and a non-display region disposed around the display region;
A first electrode formed in an island shape in each pixel region;
An auxiliary cathode electrode spaced apart from the first electrode by a predetermined distance and disposed over the entire display region;
An organic light emitting layer stacked on the first electrode; And
And a second electrode formed on the organic light emitting layer so as to cover the entire display area opposite to the first electrode and in contact with the auxiliary cathode electrode.
The method according to claim 1,
A thin film transistor formed in each of the pixel regions on the substrate;
A planarization layer covering the thin film transistor and having the first electrode and the auxiliary cathode electrode formed on an upper surface thereof;
Further comprising a bank covering the planarization layer and having a light emitting region exposing a portion of the first electrode and a cathode contact hole exposing a part of the auxiliary cathode electrode,
The organic light emitting layer is applied to the light emitting region,
Wherein the second electrode is coated on the bank and is in contact with the organic light emitting layer formed in the light emitting region and in contact with the second electrode through the cathode contact hole.
3. The method of claim 2,
And a base wiring disposed in an outermost portion of the substrate in the non-display region,
Wherein the auxiliary cathode electrode extends to the non-display region and contacts the base wire,
And the cathode contact hole includes a first cathode contact hole exposing a part of the auxiliary cathode electrode formed in the non-display area.
3. The method of claim 2,
And a base wiring disposed in an outermost portion of the substrate in the non-display region,
Wherein the auxiliary cathode electrode extends to the non-display region and contacts the base wire,
Wherein the cathode contact hole includes a second cathode contact hole exposing a part of the auxiliary cathode electrode formed in the pixel region.
3. The method of claim 2,
And a base wiring disposed in an outermost portion of the substrate in the non-display region,
Wherein the auxiliary cathode electrode extends to the non-display region and contacts the base wire,
And the cathode contact hole includes a first cathode contact hole exposing a part of the auxiliary cathode electrode formed in the non-display area and a second cathode contact hole exposing a part of the auxiliary cathode electrode formed in the pixel area The organic electroluminescent display device comprising:
A substrate defining a plurality of pixel regions arranged in a matrix manner;
A thin film transistor formed in each pixel region;
A first electrode connected to the thin film transistor and formed in a part of the pixel region;
An auxiliary cathode electrode spaced apart from the first electrode and formed in a remaining region of the pixel region surrounding the first electrode;
A bank having a light emitting region for exposing a part of the first electrode and a first cathode contact hole for exposing a part of the auxiliary cathode electrode;
An organic light emitting layer formed in the light emitting region; And
And a second electrode which is applied over the entire pixel region on the bank and is in contact with the organic light emitting layer and is in contact with the auxiliary cathode electrode through the first cathode contact hole.
The method according to claim 6,
The substrate includes a non-display region disposed in the periphery of the pixel region; And
And a base wiring disposed in the non-display area,
And the auxiliary cathode electrode extends to the non-display region and is in contact with the base wiring.
8. The method of claim 7,
The bank further includes a second cathode contact hole extended to the non-display region and exposed to expose a part of the auxiliary cathode electrode formed in the non-display region,
And the second electrode is in contact with the auxiliary cathode electrode through the second cathode contact hole.

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