KR101768489B1 - Light organic light emitting display device and method of fabricating the same - Google Patents

Abstract

The present invention relates to an organic light emitting display device capable of improving an aperture ratio, and an organic light emitting display device of the present invention includes a substrate; A gate line and a data line formed on the substrate so as to be perpendicular to each other and defining a pixel region; A switching thin film transistor and a driving thin film transistor formed in the pixel region; A first electrode connected to a drain electrode of the driving thin film transistor through a drain contact hole; A bank insulating film exposing a part of the first electrode to define an opening region; An organic light emitting layer formed on the first electrode exposed by the bank insulating film; And a second electrode formed on the organic light emitting layer, wherein the drain contact hole is formed to be parallel to the width direction of the opening region.

Description

TECHNICAL FIELD [0001] The present invention relates to an organic light emitting diode (OLED) display device and a method of manufacturing the same.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic light emitting display, and more particularly, to an organic light emitting display capable of improving an aperture ratio and a method of manufacturing the same.

The image display device that implements various information on the screen is a key technology in the era of information and communication, and it is progressing in the direction of being thinner, lighter, more portable, but higher performance. An organic light emitting display device which controls the amount of light emitted from the organic light emitting layer by using a flat panel display device has recently been spotlighted as a flexible display capable of bending due to space and convenience.

The organic light emitting display uses an electroluminescent phenomenon in which an electric field is applied to first and second electrodes formed on both ends of an organic light emitting layer to inject electrons and holes into the organic light emitting layer, Electrons and holes are paired in the organic light emitting layer and then emit while falling from the excited state to the ground state.

Such an organic light emitting display device can be formed into a thin film and can be formed on a flexible transparent substrate such as a plastic substrate. In addition, the organic light emitting display device can be manufactured in a low cost compared to a plasma display panel or an inorganic EL (Electro Luminance) It is possible to drive at a voltage (about 10V or less), and power consumption is relatively low. In addition, it has excellent properties in terms of lightness and color, and has become a target of many people.

The organic light emitting display includes a thin film transistor array portion formed on a substrate, an organic light emitting diode located on the thin film transistor array portion, and a glass cap for isolating the organic light emitting diode from the external environment.

Meanwhile, organic light emitting display devices are classified into a passive matrix type and an active matrix type. In a passive matrix type, a data line and a gate line cross each other, and sequentially drive the gate line in time to drive a pixel region in a matrix form. The passive matrix type as described above has a simple structure and a simple manufacturing method. However, the power consumption is high and it is difficult to increase the area, and the aperture ratio decreases as the number of wiring increases.

In the active matrix type, a switching thin film transistor, which is a switching element for turning on / off a pixel region, is located for each pixel region, and the pixel electrode connected to the switching thin film transistor is turned on / off in pixel units. In the active matrix type as described above, the voltage applied to the pixel region is charged in the storage capacitor, and power is applied until the next signal is applied, so that the device continues to be driven for one screen regardless of the number of gate lines. Therefore, in recent years, an active matrix type organic light emitting display device capable of achieving the same luminance with low current consumption, low power consumption, high definition and large size is mainly used.

Hereinafter, a general OLED display device will be described with reference to the accompanying drawings.

FIG. 1 is a plan view of a general OLED display, and FIG. 2 is a cross-sectional view illustrating a light emitting layer formed using a fine metal mask (FMM).

1, a general organic light emitting display device includes a switching thin film transistor STr, a driving thin film transistor DTr, a storage capacitor Cst, and an organic light emitting diode. Although not shown, the organic light emitting diode includes a first electrode, an organic light emitting layer, and a second electrode. The organic light emitting diode is formed by injecting electrons and holes into the organic light emitting layer by applying an electric field to the first and second electrodes, It emits light by energy. At this time, the light generated in the organic light emitting layer is emitted to the outside through the opening region 10, and the wider the opening region 10, the lower the current density per unit area, and the lifetime of the organic light emitting diode becomes longer.

In particular, the first electrode of the organic light emitting diode is connected to the drain electrode of the driving thin film transistor through the drain contact hole 10a. In a region where the drain contact hole 10a is formed, a current flows along the slope of the drain contact hole 10a And the deterioration of the organic luminescent layer occurs and diffuses and the lifetime of the organic luminescent display device is reduced. Therefore, the region where the drain contact hole 10a is formed is not used as the opening region 10, but a bank insulating film is formed and used as a non-opening region.

As shown in FIG. 2, since the opening 20a of the fine metal mask 20 for forming the organic light emitting layer exposes a plurality of pixel regions at once, organic materials are also deposited between the pixel regions. That is, if the drain contact hole 10a is formed in a direction parallel to the length of the opening region 10, the organic material is also deposited on the drain contact hole 10a, but the region where the drain contact hole 10a is formed is a non- Even if an organic material is deposited, it can not be used as the opening region 10.

As a result, as the aperture ratio is lowered, the current density per unit area increases in order to obtain a constant luminance, so that deterioration of the organic light emitting layer is diffused, and the lifetime of the organic light emitting display device may be shortened. Furthermore, there is a limit to increase the width of the opening region 10 of the organic light emitting layer in order to prevent the color mixing of the organic light emitting layer and to secure the thickness of the normal organic light emitting layer. The length of the opening region 10 of the organic light emitting layer has to be increased but the conventional organic light emitting display has a problem that the length of the opening region 10 due to the drain contact hole 10a formed at a position in parallel with the longitudinal direction of the opening region 10 .

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above problems, and it is an object of the present invention to provide an OLED display device capable of improving the aperture ratio by forming drain contact holes connected to an organic light emitting diode and a driving thin film transistor in a width direction of an opening region, And a method for producing the same.

According to an aspect of the present invention, there is provided an organic light emitting diode display comprising: a substrate; A gate line and a data line formed on the substrate so as to be perpendicular to each other and defining a pixel region; A switching thin film transistor and a driving thin film transistor formed in the pixel region; A first electrode connected to a drain electrode of the driving thin film transistor through a drain contact hole; A bank insulating film exposing a part of the first electrode to define an opening region; An organic light emitting layer formed on the first electrode exposed by the bank insulating film; And a second electrode formed on the organic light emitting layer, wherein the drain contact hole is formed to be parallel to the width direction of the opening region.

The first electrode may have a structure in which a transparent conductive material and an opaque conductive material are stacked, and the second electrode is formed of a transparent conductive material.

A method of manufacturing an organic light emitting display according to an embodiment of the present invention includes forming a gate line and a data line for defining a pixel region in a matrix form on a substrate and forming a switching thin film transistor and a driving thin film transistor ; Forming a protective film and a planarizing film on the substrate including the switching thin film transistor and the driving thin film transistor in order; Selectively removing the protective film and the planarization film to form a drain contact hole exposing a drain electrode of the driving thin film transistor; Forming a first electrode on the planarization layer, the first electrode being connected to the drain electrode through the drain contact hole; Forming a bank insulating layer which exposes a part of the first electrode on the planarization layer including the first electrode to define an opening region; Forming an organic light emitting layer on the exposed first electrode; And forming a second electrode on the organic light emitting layer, wherein the drain contact hole is formed to be parallel to the width direction of the opening region.

The organic light emitting layer is formed using a Grill-type fine metal mask.

The grill-type fine metal mask has openings that expose all pixel regions in the same row.

And the drain contact hole is formed in a region in parallel with the width direction of the opening of the fine metal mask.

The organic light emitting display of the present invention can improve the aperture ratio by forming the drain contact holes connected to the organic light emitting diode and the driving thin film transistor in the width direction of the opening region. Therefore, the current density per unit area is lowered, and the lifetime of the organic light emitting diode is prolonged.

1 is a plan view of a general organic light emitting display device.
2 is a cross-sectional view illustrating the formation of a light-emitting layer using a fine metal mask (FMM).
FIG. 3A is a plan view of the organic light emitting diode display of the present invention, and FIG. 3B is a cross-sectional view taken along the line I-I 'of FIG. 3A.
FIG. 4A is a plan view showing an opening region of a general organic light emitting display device, and FIG. 4B is a plan view showing an opening region of the organic light emitting display device of the present invention. FIG.
FIGS. 5A to 5D are plan views showing a method of manufacturing an organic light emitting display according to the present invention, and FIGS. 6A to 6D are cross-sectional views taken along the line I-I 'in FIGS. 5A to 5D.
7A to 7C are plan views showing a step of forming an organic light emitting layer using a fine metal mask.

The organic light emitting display of the present invention is an active matrix type organic light emitting display, and the organic light emitting display of the present invention will be described in detail as follows.

FIG. 3A is a plan view of the organic light emitting diode display of the present invention, and FIG. 3B is a cross-sectional view taken along the line I-I 'of FIG. 3A.

3A and 3B, the organic light emitting diode display of the present invention includes a substrate 100, a gate line GL and a data line DL vertically intersecting the substrate 100, a power line PL A switching thin film transistor STr, a driving thin film transistor DTr, a storage capacitor Cst, and an organic light emitting diode. At this time, the positions of the switching thin film transistor STr and the driving thin film transistor DTr may be different for each model.

Specifically, the gate lines GL are formed in the first direction and the data lines DL are formed in the second direction perpendicular to the gate lines GL, so that the gate lines GL and the data lines DL, A plurality of pixel regions P are defined in this matrix form.

A switching thin film transistor STr is formed at the intersection of the gate line GL and the data line DL so that the gate line GL supplies a scan signal to the switching thin film transistor STr, Supplies a data signal to the switching thin film transistor STr. A power line PL formed in parallel with the gate line GL and in parallel with the data line DL supplies a power signal to the driving thin film transistor DTr.

A storage capacitor Cst is formed between the second gate electrode 110b and the second source electrode 140c of the driving thin film transistor DTr with the gate insulating film 120 interposed therebetween. The storage capacitor Cst is for maintaining the gate voltage of the driving thin film transistor DTr to be recognized. Even if the switching thin film transistor STr is turned off, the storage capacitor Cst can maintain a constant current level flowing through the organic light emitting diode.

The switching thin film transistor STr has a first gate electrode 110a connected to the gate line GL, a first source electrode 140a connected to the data line DL, and a first source electrode 140a, A first drain electrode 140b connected to the second gate electrode 110b and the storage capacitor Cst of the thin film transistor DTr, a channel portion formed between the first source electrode 140a and the first drain electrode 140b A data signal supplied to the data line DL is applied to the storage capacitor Cst and the second gate electrode of the driving thin film transistor DTr when the scan signal is supplied to the gate line GL. And supplied to the electrode 110b.

The driving thin film transistor DTr includes a second gate electrode 110b connected to the first drain electrode 140b of the switching thin film transistor STr through the connection electrode 170a and a second gate electrode 110b connected to the power line PL. A second source electrode 140c and a second drain electrode 140d facing the source electrode 140c and the second source electrode 140c and connected to the first electrode 170b of the organic light emitting diode, And a second active layer 130b which forms a channel part between the first active layer 130a and the second active layer 130b. In response to a data signal supplied to the second thin film transistor DTr and the second gate electrode 110b, a current supplied from the power line PL to the organic light emitting diode is controlled to adjust the amount of light emitted from the organic light emitting diode.

The connection electrode 170a is electrically connected to the first drain electrode 140b and the second gate electrode 110b through the first and second contact holes 160a and 160b formed by selectively removing the passivation layer 150 and the planarization layer 160. [ ). The first contact hole 160a penetrates the passivation layer 150 and the planarization layer 160 to expose the first drain electrode 140b and the second contact hole 160b exposes the gate insulating layer 120, (150) and the planarization layer (160) to expose the second gate electrode (110b).

The organic light emitting diode includes a first electrode 170b formed on the planarization layer 160, an organic light emitting layer 190 formed on the first electrode 170b, and a second electrode 200 formed on the organic light emitting layer 190 . The first electrode 170b is connected to the pixel electrode through the second drain electrode 140d of the driving thin film transistor DTr and the drain contact hole 160c so that the upper portion of the organic light emitting layer 190 And a hole injecting layer, a hole transporting layer, a charge transporting layer, and an electron injecting layer are formed at the bottom.

Part of the first electrode 170b is exposed through the bank insulating layer 180 and the organic light emitting layer 190 is formed on the exposed first electrode 170b. An aperture region of the pixel region is defined.

As described above, generally, the organic light emitting layer is formed using a Grill-type fine metal mask (FMM), and the fine metal mask is formed in a pixel region As shown in Fig. Accordingly, when the drain contact hole 160c is formed in a direction parallel to the length of the opening of the fine metal mask as in a general organic light emitting display, organic material is also deposited on the region where the drain contact hole 160c is formed.

However, since the region where the drain contact hole 160c is formed is a non-opening region, the first electrode 170b in the region corresponding to the drain contact hole 160c is covered with the bank insulating film 180, and the opening ratio is lowered. That is, as the aperture ratio is lowered, the current density per unit area increases in order to obtain a constant luminance, and deterioration of the organic light emitting layer 190 may be diffused, and the lifetime of the organic light emitting display device may be reduced.

The organic light emitting diode display according to the present invention includes a drain contact hole 160c connecting the second drain electrode 140d of the driving thin film transistor DTr and the first electrode 170b of the organic light emitting diode, And is formed to be parallel to the width direction of the opening of the fine metal mask. Therefore, organic materials are not deposited on the drain contact hole 160c of the organic light emitting diode display of the present invention, and the organic light emitting display device is used as an opening region up to a region where the drain contact hole of a general organic light emitting display device is formed. The aperture ratio is improved.

FIG. 4A is a plan view showing an opening region of a general organic light emitting display device, FIG. 4B is a plan view showing an opening region of the organic light emitting display according to the present invention, and FIG. 4B is a plan view showing a first electrode, a drain contact hole, Respectively.

4A, a general organic light emitting display is formed in a region where drain electrodes of a driving thin film transistor and drain contact holes, which are connected to a first electrode of the organic light emitting diode, are aligned with the longitudinal direction of the opening region defined by the bank insulating film . When the organic light emitting layer is formed using the fine metal mask as described above, the organic material is also deposited in the region where the drain contact hole is formed. However, since the region where the drain contact hole is formed is the non- The aperture ratio is 20.3%, 20.3%, and 33.2%, respectively. This is the ratio of the aperture area in the pixel area.

However, as shown in FIG. 4B, the organic light emitting display of the present invention is formed in a region where the drain electrode of the driving thin film transistor and the drain contact hole, which is connected to the first electrode of the organic light emitting diode, are in parallel with the width direction of the opening region. The opening region can be used as an opening region up to the region where the drain contact hole of the organic light emitting display device is formed. That is, the aperture ratios of the R, G, and B organic light emitting layers are 22.0%, 22.0%, and 35.9%, respectively, which is about 10% larger than the aperture ratio of the organic light emitting layer of a general organic light emitting display.

Accordingly, the organic light emitting display according to the present invention has an increased aperture ratio as compared with a general organic light emitting display, so that the current density per unit area is lowered, and the lifetime of the organic light emitting diode is prolonged.

Meanwhile, the organic light emitting diode display of the present invention is an upper light emitting organic light emitting display, and emits light in a direction opposite to the substrate. Accordingly, the first electrode may be formed of a transparent conductive material, such as TO (Tin Oxide), ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide), ITZO (Indium Tin Zinc Oxide) (Nd) / Cr, Mo / Al (Nd) / Mo, Cu / Mo, Ti / Al (Nd) / Ti, Mo / Al, Mo / Ti / Al (Nd), Cu alloy / Mo, Cu alloy / Al, Cu alloy / Mo alloy, Cu alloy / Al alloy, Al / Mo alloy, Mo alloy / Al, Al alloy / An alloy / Al alloy, a Mo / Al alloy, or the like. In particular, the opaque conductive material is preferably a material having high reflectance so as to effectively reflect light emitted from the organic light emitting layer and emit the light to the outside. The second electrode is formed of a transparent conductive material having a high transmittance to emit light formed in the organic light emitting layer upward.

Hereinafter, a method of manufacturing the organic light emitting display device of the present invention will be described in detail.

FIGS. 5A to 5D are plan views showing a method of manufacturing an organic light emitting display according to the present invention, and FIGS. 6A to 6D are cross-sectional views taken along a line I-I 'in FIGS. 7A to 7C are plan views showing a step of forming an organic light emitting layer using a fine metal mask.

5A and 6A, a gate line GL, a data line DL and a power line PL are formed on a substrate 100 and a switching thin film transistor STr and a driving thin film transistor DTr are formed do. The method of forming the gate line GL, the data line DL, the power line PL, the switching thin film transistor STr, and the driving thin film transistor DTr is a general method and therefore will not be described.

A passivation layer 150 and a planarization layer 160 are formed on the entire surface of the substrate 100 including the switching thin film transistor STr and the driving thin film transistor DTr and the passivation layer 150 and the planarization layer 160 are selectively removed The first and second contact holes 160a and 160b are formed to expose the first drain electrode 140b of the switching thin film transistor STr and the second gate electrode 110b of the driving thin film transistor DTr, And a drain contact hole 160c exposing the second drain electrode 140d of the driving thin film transistor DTr are formed. At this time, the drain contact hole 160c is formed in a direction parallel to the width direction of the opening region to be defined later.

The first drain electrode 140b of the switching thin film transistor STr and the second gate electrode of the driving thin film transistor DTr are formed on the planarization layer 160 through the first and second contact holes 160a and 160b And a first electrode 170b connected to the second drain electrode 140d of the driving thin film transistor DTr is formed through the drain contact hole 160c.

In particular, since the organic light emitting display of the present invention is a top emission type in which light is emitted in a direction opposite to the substrate 100, the first electrode 170b may be a structure in which a transparent conductive material and an opaque conductive material having a high reflectance are sequentially stacked have.

5B and 6B, a bank insulating layer 180 exposing a part of the first electrode 170b is formed on the planarization layer 160 including the connection electrode 170a and the first electrode 170b . At this time, the opening region of the unit pixel region is defined by the exposed first electrode 170b.

5C and 6C, an organic material is deposited on the exposed first electrode 170b by using a fine metal mask having an opening to form an organic light emitting layer 190. Referring to FIG. Specifically, as shown in FIG. 7A, a fine metal mask (FMM) 30 having an opening 30a is made to correspond to the substrate. At this time, since the fine metal mask 30 is of a grille type and the opening 30a exposes not only the first electrode 170b exposed through the bank insulating film 180 but also a plurality of pixel regions at once, The aperture ratio of the organic light emitting display device can be improved as compared with the case of forming the organic light emitting layer using a Solt-type fine metal mask.

Accordingly, a red light emitting material is deposited on the first electrode 170b exposed in the opening region to form a red (R) light emitting layer, and the fine metal mask 30 is sequentially moved as shown in FIGS. 7B and 7C, And a blue light emitting material are deposited to form a green (G) light emitting layer and a blue (B) light emitting layer.

Since the drain contact holes 160b of the present invention are formed so as to be parallel to the width direction of the opening region, the light shielding portions (not shown) of the mask 30 do not correspond to the openings 30b of the fine metal mask 30 30b. Therefore, the organic light emitting diode display of the present invention can use the position where the drain contact hole of the general organic light emitting display device is formed as an opening region, thereby improving the aperture ratio.

Finally, as shown in FIGS. 5D and 6D, a second electrode 200 is formed on the organic light emitting layer 190. In this case, since the organic light emitting display of the present invention is an upper light emitting type, the second electrode 200 may include at least one selected from the group consisting of Tin Oxide (ITO), Indium Tin Oxide (ITO), Indium Zinc Oxide (IZO), Indium Tin Zinc Oxide It is preferable to use a transparent conductive material.

While the present invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. Will be apparent to those of ordinary skill in the art.

30: fine metal mask 30a: opening
30b: shielding part 100: substrate
110a: first gate electrode 110b: second gate electrode
120: gate insulating film 130a: first active layer
130b: second active layer 140a: first source electrode
140b: first drain electrode 140c: second source electrode
140d: second drain electrode 150: protective film
160: planarization layer 160a: first contact hole
160b: second contact hole 160c: drain contact hole
170a: connection electrode 170b: first electrode
180: bank insulating film 190: organic light emitting layer
200: second electrode

Claims (6)

Board;
A gate line and a data line for defining pixel regions perpendicularly intersecting each other on the substrate;
A switching thin film transistor and a driving thin film transistor provided in the pixel region;
A first electrode connected to a drain electrode of the driving thin film transistor through a drain contact hole;
A bank insulating film exposing a part of the first electrode to define an opening region;
An organic light emitting layer disposed on the first electrode exposed by the bank insulating film; And
And a second electrode located on the organic light emitting layer,
Wherein the drain contact hole faces the opening region only in the gate line direction. The method according to claim 1,
Wherein the first electrode is a structure in which a transparent conductive material and an opaque conductive material are stacked, and the second electrode is a transparent conductive material. Forming a gate line and a data line for defining a pixel region in a matrix form on a substrate, and forming a switching thin film transistor and a driving thin film transistor;
Forming a passivation layer and a planarization layer in this order on the substrate including the switching thin film transistor and the driving thin film transistor;
Selectively removing the protective film and the planarization layer to form a drain contact hole exposing a drain electrode of the driving thin film transistor;
Forming a first electrode on the planarization layer, the first electrode being connected to the drain electrode through the drain contact hole;
Forming a bank insulating layer which exposes a part of the first electrode on the planarization layer including the first electrode to define an opening region;
Forming an organic light emitting layer on the exposed first electrode; And
And forming a second electrode on the organic light emitting layer,
Wherein the drain contact hole faces the opening region only in the gate line direction. The method of claim 3,
Wherein the step of forming the organic light emitting layer is performed using a fine metal mask of a Grill type. 5. The method of claim 4,
Wherein the grill-type fine metal mask has openings for exposing all pixel regions of the same row. 6. The method of claim 5,
Wherein the drain contact hole is formed at a position in parallel with the width direction of the opening of the fine metal mask.

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