KR20150015237A - Organic light emitting display device and method of fabricating thereof - Google Patents

Abstract

The present invention provides an organic light emitting display device capable of preventing degradation of a property due to a permeation of hydrogen from an organic light emitting layer to a thin film transistor. The organic light emitting display device includes: a first substrate and a second substrate which include a plurality of pixels; the thin film transistor formed on each pixel of the first substrate; a color filter layer formed on each pixel; an insulation layer formed on the color filter layer; a pixel electrode formed on the insulation layer; a hydrogen absorbing layer formed on the upper side of the thin film transistor, absorbing the hydrogen diffused to the thin film transistor; an organic light emitting unit formed on the hydrogen absorbing layer and the pixel electrode, emitting light; and a common electrode formed on the organic light emitting unit.

Description

TECHNICAL FIELD [0001] The present invention relates to an organic electroluminescent display device and a method of manufacturing the same. BACKGROUND ART < RTI ID = 0.0 >

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an organic light emitting display device, and more particularly, to an organic light emitting display device having a hydrogen absorbing layer on an oxide semiconductor layer to prevent deterioration of characteristics of an oxide semiconductor due to penetration of hydrogen, .

Recently, organic electroluminescent devices using poly (p-phenylenevinylene) (PPV), which is one of conjugate polymers, have been developed, and research on organic materials such as conjugated polymers having conductivity has progressed actively . Studies for applying such organic materials to thin film transistors (TFTs), sensors, lasers, photoelectric elements and the like have been continuing, and organic electroluminescent display devices have been actively studied.

In the case of an electroluminescent device made of a phosphorescent inorganic material, an AC voltage of 200 V or more is required, and since the manufacturing process of the device is formed by vacuum deposition, it is difficult to increase the size of the device. Especially, have. However, since an electroluminescent device made of an organic material can develop an electroluminescent device capable of easily producing an electroluminescent device with excellent light emission efficiency, easiness of large-scale surface preparation, simplicity of process, particularly blue light emission, And is spotlighted as a display device.

Currently, an active matrix organic light emitting display device including active driving elements in each pixel is actively studied as a flat panel display in the same manner as a liquid crystal display device. Particularly, in recent years, thin film transistors including oxide semiconductors having good characteristics, simple manufacturing process, and large area can be mainly employed for such organic electroluminescent display devices.

However, in the case of using the oxide semiconductor as described above, there are the following problems. Generally, an organic light emitting layer is formed on a thin film transistor including an oxide semiconductor. As the organic light emitting display device having such a structure is used for a long time, hydrogen contained in the organic light emitting layer is diffused and penetrates into the underlying oxide semiconductor.

As described above, when hydrogen penetrates into the oxide semiconductor, an off current is generated in the thin film transistor, deteriorating the characteristics of the thin film transistor, and causing defects in the liquid crystal display element.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an organic electroluminescence display device and a method of manufacturing the same that can prevent deterioration of characteristics of a thin film transistor due to penetration of hydrogen.

According to an aspect of the present invention, there is provided an organic light emitting display device including: a first substrate and a second substrate including a plurality of pixels; A thin film transistor formed on each pixel of the first substrate; A color filter layer formed on each pixel; An insulating layer formed on the color filter layer; A pixel electrode for each pixel on the insulating layer; A hydrogen absorbing layer formed on the thin film transistor to absorb hydrogen diffused into the thin film transistor; An organic light emitting unit formed on the hydrogen absorbing layer and the pixel electrode to emit light; And a common electrode formed on the organic light emitting portion.

The hydrogen absorbing layer is made of an oxide semiconductor such as IGZO (Indium Gallium Zinc Oxide). The pixel electrode extends over the thin film transistor, and the hydrogen absorbing layer is not extended to the pixel. Further, the hydrogen absorbing layer may extend to the pixel and have conductivity. At this time, the hydrogen absorbing layer has a work function larger than that of the pixel electrode, so that the efficiency of injecting holes into the organic light emitting layer is improved.

According to another aspect of the present invention, there is provided a method of manufacturing an organic electroluminescent display device, including: providing a first substrate and a second substrate including a plurality of pixels; Forming a thin film transistor on each pixel of the first substrate; Forming a color filter layer on each pixel; Forming a hydrogen absorbing layer for absorbing hydrogen diffused into the pixel electrode and the thin film transistor; Forming a bank layer between pixels; Forming an organic light emitting portion for emitting light on the pixel electrode and the hydrogen absorbing layer; Forming a common electrode on the organic light emitting portion; And bonding the first substrate and the second substrate together.

The forming of the pixel electrode and the hydrogen absorbing layer may include continuously forming a metal oxide and an oxide semiconductor on the first substrate and forming a photoresist layer thereon; Developing the photoresist layer using a diffraction mask or a halftone mask to form a first photoresist pattern having different thicknesses; Forming a pixel electrode by simultaneously etching the metal oxide and the oxide semiconductor using the first photoresist pattern; Forming a second photoresist pattern by aging the first photoresist pattern; And a step of etching the oxide semiconductor of the pixel using the second photoresist pattern to form a hydrogen absorbing layer on the thin film transistor. Alternatively, the metal oxide and the oxide semiconductor may be successively deposited on the first substrate, Etching the metal oxide and the oxide semiconductor all at once; Forming a bank layer between the pixels to expose the oxide semiconductor of the pixel between the bank layers; And removing the oxide semiconductor of the pixel by etching the exposed oxide semiconductor.

The forming of the pixel electrode and the hydrogen absorbing layer may include continuously depositing a metal oxide and an oxide semiconductor on the first substrate, etching the metal oxide and the oxide semiconductor all at once by a photolithography process, Forming a bank layer between the pixels to expose the oxide semiconductor of the pixel between the bank layers; And a step of surface-treating the exposed oxide semiconductor with a plasma to form an oxide semiconductor of the pixel as a conductive layer.

In the present invention, a hydrogen absorbing layer is formed on the thin film transistor so that the hydrogen diffused from the organic light emitting material is absorbed by the hydrogen absorbing layer, thereby preventing the characteristics of the driving thin film transistor from deteriorating.

In addition, in the present invention, by forming the pixel electrode on the thin film transistor, it is possible to prevent foreign substances such as particles from penetrating into the driving thin film transistor when the panel formed by the mother substrate unit is cut in unit panel unit So that defects of the driving thin film transistor due to foreign substances can be prevented.

1 is an equivalent circuit diagram of an organic electroluminescence display device according to the present invention.
2 is a cross-sectional view illustrating a structure of an organic light emitting display device according to a first embodiment of the present invention.
3 is a view illustrating a structure of an organic light emitting display device according to a second embodiment of the present invention.
4A to 4E are views showing a method of manufacturing an organic electroluminescence display device according to the present invention.
5A to 5E are views showing an example of a method of forming a pixel electrode and a hydrogen absorbing layer in the method for manufacturing an organic electroluminescence display device of the present invention.
6A and 6B are views showing another example of a method of forming a pixel electrode and a hydrogen absorbing layer in the method of manufacturing an organic electroluminescence display element of the present invention.
7A and 7B are views showing still another example of a method of forming a pixel electrode and a hydrogen absorbing layer in the method for manufacturing an organic electroluminescence display device of the present invention.

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

1 is an equivalent circuit diagram of an organic light emitting display device according to the present invention. 1, an organic light emitting display device 1 is composed of a plurality of pixels defined by a gate line G and a data line D which cross each other in the vertical and horizontal directions, (P) are arranged in parallel with the data line (D).

In each pixel, a switching thin film transistor Ts, a driving thin film transistor Td, a capacitor C and an organic light emitting element E are provided. The gate electrode of the switching thin film transistor Ts is connected to the gate line G, the source electrode thereof is connected to the data line D and the drain electrode thereof is connected to the gate electrode of the driving thin film transistor Td. The source electrode of the driving transistor Td is connected to the power line P and the drain electrode of the driving transistor Td is connected to the light emitting element E.

When a scanning signal is inputted through the gate line G in the organic EL display device having such a configuration, a signal is applied to the gate electrode of the switching TFT Ts to drive the switching TFT Ts. As the switching TFT Ts is driven, a data signal input through the data line D is input to the gate electrode of the driving TFT Td through the source electrode and the drain electrode, so that the driving TFT Td .

At this time, a current flows in the power line P, and the current of the power line P is applied to the light emitting element E through the source electrode and the drain electrode as the driving thin film transistor Td is driven. At this time, the current outputted through the driving thin film transistor Td varies in size depending on the voltage between the gate electrode and the drain electrode.

The light emitting element E emits light as an electric current flows through the driving thin film transistor Td as an organic light emitting element to display an image. At this time, since the intensity of the light emitted varies according to the intensity of the applied current, the intensity of the light can be controlled by adjusting the intensity of the current.

FIG. 2 is a cross-sectional view showing an actual structure of an organic light emitting display device according to a first embodiment of the present invention, and the structure of the organic light emitting display device according to the present embodiment will be described as follows.

As shown in FIG. 2, the organic light emitting display according to the present embodiment includes an R pixel for outputting red light, a G pixel for outputting green light, and a B pixel for outputting blue light. Although not shown in the drawing, the organic light emitting display device of the present invention may include a W pixel for outputting white light. At this time, the W pixel outputs white light, thereby improving the overall luminance of the organic light emitting display device.

A color filter layer is formed in each of the R, G, and B pixels to output white light output from the organic light emitting portion as light of a specific color. However, if W pixels are disposed, .

As shown in FIG. 2, a first substrate 10 made of a transparent material such as glass or plastic is divided into R, G, and B pixels, and a driving thin film transistor is formed in each of R, G, and B pixels.

The driving thin film transistor includes gate electrodes 11R, 11G and 11B formed on the R, G and B pixels on the first substrate 10 and a first substrate 10R, 11G and 11B on which the gate electrodes 11R, 12G and 12B formed on the semiconductor layers 12R, 12G and 12B and the source electrodes 14R, 14G and 14B and the drain electrodes 15R, 15G and 15B formed on the semiconductor layers 12R, 12G and 12B. Although not shown in the drawing, an etching stopper is formed on a part of the upper surface of the semiconductor layers 12R, 12G, and 12B so as to expose the semiconductor substrate 12 during the etching of the source electrodes 14R, 14G, and 14B and the drain electrodes 15R, 15G, It is possible to prevent the layers 12R, 12G, and 12B from being etched.

The gate electrode (11R, 11G, 11B) are Cr, Mo, Ta, Cu, Ti, may be formed of a metal such as Al or Al alloy, the gate insulating layer 22 is insulating inorganic, such as SiO ₂ or SiNx It may be a layer of double made of a single layer or a SiO ₂ and SiNx made of a material. The semiconductor layers 12R, 12G, and 12B are formed of a transparent oxide semiconductor such as IGZO (Indium Gallium Zinc Oxide). The source electrodes 14R, 14G, and 14B and the drain electrodes 15R, 15G, and 15B may be formed of Cr, Mo, Ta, Cu, Ti, Al, or Al alloy.

A first insulating layer 24 is formed on the first substrate 10 on which the driving thin film transistor is formed. The first insulating layer 24 may be formed of an inorganic insulating material such as SiO _{2 to} a thickness of about 4500 ANGSTROM. An R-color filter layer 17R, a G-color filter layer 17G, and a B-color filter layer 17B are formed on the R, G, and B pixels of the first insulating layer 24, respectively.

A second insulating layer 26 is formed on the R-color filter layer 17R, the G color filter layer 17G, and the B color filter layer 17B. The second insulating layer 26 is an overcoat layer for planarizing the first substrate 10, and an organic insulating material such as photo-acryl can be formed to a thickness of about 3 탆.

The pixel electrodes 21R, 21G, and 21B are formed on the R, G, and B pixels on the first insulating layer 26, respectively. At this time, contact holes 29 are formed in the upper first insulating layer 24 and the second insulating layer 26 of the drain electrodes 15R, 15G, and 15B of the driving thin film transistors formed in the R, G, The pixel electrodes 21R, 21G and 21B are formed in the contact holes 29 and are electrically connected to the drain electrodes 15R, 15G and 15B of the exposed driving thin film transistors. At this time, the pixel electrodes 21R, 21G, and 21B are formed in R, G, and B pixels, but are not formed on the driving thin film transistor. That is, the pixel electrodes 21R, 21G, and 21B are formed only in the image display regions of the R, G, and B pixels.

In addition, a bank layer 28 is formed in each pixel boundary region on the second insulating layer 26. The bank layer 28 is a kind of barrier rib for preventing each pixel from being mixed and outputting light of a specific color outputted from adjacent pixels. Since the bank layer 28 fills a portion of the contact hole 29, the step is reduced. As a result, charge is concentrated on the step of forming the organic light emitting portion 23, so that the life of the organic light emitting portion 23 Can be prevented from deteriorating.

The pixel electrodes 21R, 21G and 21B are made of transparent metal oxide materials such as indium tin oxide (ITO) and indium zinc oxide (IZO). In the present invention, R, G, and B pixels.

A hydrogen absorbing layer 27 is formed on the pixel electrodes 21R, 21G, and 21B. The hydrogen absorbing layer 27 is formed of an oxide such as IGZO (Indium Gallium Zinc Oxide), IZO (Indium Tin Oxide), ZnO (Zinc Oxide) or ITZO (Indium Tin Zinc Oxide) The hydrogen absorbing layer 27 prevents hydrogen from penetrating into the oxide semiconductor layer of the driving thin film transistor. Of course, any material can be used as long as the hydrogen absorbing layer 27 is not limited to the material but can absorb hydrogen.

When hydrogen generated in the organic light emitting portion penetrates into the oxide semiconductor, an off current is generated in the driving thin film transistor. Such off current is an important cause of deterioration of the characteristics of the thin film transistor. In the present invention, the hydrogen absorbing layer 27 is formed on the driving thin film transistor so that the hydrogen absorbing layer 27 absorbs hydrogen penetrating into the driving thin film transistor in the organic light emitting portion, thereby preventing hydrogen penetration. As a result, Defects due to deterioration of characteristics of the transistor can be prevented.

The hydrogen absorbing layer 27 is formed on the pixel electrodes 21R, 21G and 21B while the pixel electrodes 21R, 21G and 21B are formed on the upper parts of the driving TFT and the R, G and B pixels, (27) are formed only on the upper portion of the driving thin film transistor and are not formed inside the R, G, and B pixels. Thus, the pixel electrodes 21R, 21G and 21B and the hydrogen absorbing layer 27 are formed on the driving thin film transistor, but only the pixel electrodes 21R, 21G and 21B are formed in the R, G and B pixels.

As described above, since the hydrogen absorbing layer 27 is not formed in the R, G, and B pixels, the light absorption by the hydrogen absorbing layer 27 can be prevented during the image realization and the decrease in the brightness by the hydrogen absorbing layer 27 can be prevented .

In addition, by forming a double layer of the hydrogen absorbing layer 27 and the pixel electrodes 21R, 21G, and 21B on the driving thin film transistor, the following effects can be obtained.

First, hydrogen permeation into the driving thin film transistor can be prevented by the hydrogen absorbing layer 27.

Secondly, when a mother layer is formed in units of a panel after a bank layer is formed in units of mother substrates, foreign particles such as particles penetrate into the driving thin film transistor. Or a metal oxide such as IZO (that is, a pixel electrode) can prevent the penetration of foreign matter, thereby preventing defects of the driving thin film transistor due to foreign substances.

However, in the present invention, only the hydrogen absorbing layer 27 may be formed without forming the pixel electrodes 21R, 21G, and 21B on the driving thin film transistor. Even in this case, since the hydrogen absorbing layer 27 prevents hydrogen from penetrating into the organic light emitting portion, the object of the present invention can be sufficiently achieved.

An organic light emitting portion 23 made of an organic light emitting material is formed between the bank layers 28 on the pixel electrodes 21R, 21G, and 21B. The organic light emitting portion 23 includes a white organic light emitting layer for emitting white light. The white organic light emitting layer may be formed by mixing a plurality of organic materials that emit red, green, and blue monochromatic light, or a plurality of light emitting layers that emit red, green, and blue monochromatic light, respectively. Although not shown in the drawing, the organic light emitting portion 23 includes not only an organic light emitting layer but also an electron injection layer for injecting electrons and holes into the organic light emitting layer, an electron injection layer for transporting the injected electrons and holes to the organic light emitting layer, And a hole transport layer may be formed.

A common electrode 25 is formed on the entire surface of the first substrate 10 on the organic light emitting portion 23. The common electrode 25 is made of Ca, Ba, Mg, Al, Ag or the like.

At this time, when the common electrode 25 is the cathode of the organic light emitting portion 23 and the pixel electrodes 21R, 21G and 21B are the anode, a voltage is applied to the common electrode 25 and the pixel electrodes 21R, 21G and 21B The electrons are injected from the common electrode 25 into the organic light emitting portion 23 and the holes from the pixel electrodes 21R, 21G and 21B are injected into the organic light emitting portion 23, As the exciton is decayed, light corresponding to energy difference between LUMO (Lowest Unoccupied Molecular Orbital) and HOMO (Highest Occupied Molecular Orbital) of the light emitting layer is generated, 10). At this time, red light, green light, and blue light are emitted in the R, G, and B light emitting layers included in the organic light emitting layer, respectively, and these lights are mixed to emit white light. The divergent white light passes through the R, G, and B-color filter layers 17R, 17G, and 17B, respectively, and outputs only light of a color corresponding to the pixel.

A second substrate 50 is disposed on the common electrode 25 to form an adhesive layer 42. The second substrate 50 is bonded to the first substrate 50 by the adhesive layer 42, (10).

As the adhesive, any material can be used as long as it has good adhesion and good heat resistance and water resistance. In the present invention, a thermosetting resin such as an epoxy compound, an acrylate compound or an acrylic rubber is used. At this time, the adhesive layer 42 is applied in a thickness of about 5-100 [mu] m and cured at a temperature of about 80-170 [deg.] C. The adhesive layer 42 not only bonds the first substrate 10 and the second substrate 50, but also acts as an encapsulant for preventing moisture from penetrating into the organic light emitting display device. Therefore, although the term 42 is referred to as an adhesive in the detailed description of the present invention, this is for convenience only, and the adhesive layer may be referred to as an encapsulant.

The second substrate 50 is an encapsulation cap for encapsulating the adhesive layer 42. The encapsulation cap may be a PS (Polystyrene) film, a PE (polyethylene) film, a PEN (polyethylene naphthalate) Can be made of the same protective film. In addition, the second substrate 50 may be made of plastic or glass, and any material can be used as long as it can protect the components formed on the first substrate 10.

Although not shown in the drawings, an auxiliary electrode formed between the first substrate 10 and the second substrate 50 in the outer region of the organic light emitting display device and supplying a common voltage to the common electrode 25 may be formed .

As described above, in the present invention, a hydrogen absorbing layer 27 made of an oxide such as IGZO, IZO, ZnO, or ITZO is provided on the upper portion of the driving thin film transistor. The hydrogen absorbing layer 27 diffuses from the organic light emitting portion 23, It is possible to prevent the hydrogen from penetrating into the driving thin film transistor to be combined with the oxide semiconductor in the driving thin film transistor to deteriorate the characteristics of the driving thin film transistor.

3 is a cross-sectional view illustrating a structure of an organic light emitting display device according to a second embodiment of the present invention. The organic electroluminescent display device of this embodiment and the organic electro-luminescent display device of the first embodiment differ from each other only in the pixel electrode, but the other structures are the same.

The pixel electrodes 21R, 21G and 21B and the hydrogen absorbing layer 27 are formed on the R, G and B pixels on the first insulating layer 26, respectively. In this embodiment, the hydrogen absorbing layer 27 is formed only on the upper portion of the driving thin film transistor and not formed in the R, G, and B pixels in the first embodiment, And a double layer of the pixel electrodes 21R, 21G, and 21B and the hydrogen absorbing layer 27 are formed on the upper portion of the driving thin film transistor and the R, G, and B pixels.

At this time, the surface of the hydrogen absorbing layer 27 formed in the R, G, and B pixels is treated with plasma to have conductivity. That is, the surface of the IGZO layer is surface-treated with a plasma such as nitrogen, argon, helium, or hydrogen to have conductivity.

The pixel electrodes 21R, 21G and 21B inject holes into the organic light emitting layer as an anode and the common electrode 25 inject electrons into the organic light emitting layer as cathodes. The anode uses a metal having a high work function and the anode uses a metal having a low work function to facilitate the injection of holes and electrons. Generally, the larger the work function of the anode, the more smoothly the holes are injected into the organic light emitting layer and the smaller the work function of the cathode, the more easily the electrons are injected into the organic light emitting layer.

When the pixel electrodes 21R, 21G, and 21B are made of ITO, the work function of the IGZO is about 5-6 eV, while the work function of the IGZO is larger than that of the ITO.

Therefore, when a conductorized IGZO layer, that is, a conductorized hydrogen absorbing layer 27 is formed on the pixel electrodes 21R, 21G, and 21B in the R, G, and B pixels and IGZO / ITO is formed as the pixel electrode, Since the work function of the IGZO contacting the portion 23 is larger than that of ITO, holes are injected more smoothly into the organic light emitting portion 23, and the light emitting efficiency of the organic light emitting portion 23 is improved, Thereby improving the efficiency.

In this embodiment, the pixel electrodes 21R, 21G, and 21B and the hydrogen absorbing layer 27 are formed in a double layer on the driving thin film transistor to prevent penetration of hydrogen and foreign matter into the driving thin film transistor, 27 may be formed.

Hereinafter, a method of manufacturing the organic light emitting display device having the above structure will be described. At this time, the manufacturing method is the manufacturing method for the organic light emitting display device having the structure shown in FIG. 2, but the organic light emitting display device having the structure shown in FIG. 3 may be formed by the same method.

4A to 4E are views showing a method of manufacturing an organic electroluminescent display device according to the present invention.

First, as shown in FIG. 4A, a first substrate 10 made of a transparent material such as glass or plastic is prepared, and then an opaque material such as Cr, Mo, Ta, Cu, Ti, Al, The metal is deposited by a sputtering process and then etched by a photolithography process to form the gate electrodes 11R, 11G, and 11B.

Thereafter, an inorganic insulating material is deposited on the entire first substrate 10 on which the gate electrodes 11R, 11G, and 11B are formed by a CVD (Chemical Vapor Deposition) method to form the gate insulating layer 22. [ At this time, the gate insulating layer 22 may be formed to a thickness of about 2000 Å of SiNx.

Then, a transparent oxide semiconductor such as IGZO (Indium Gallium Zinc Oxide) is deposited over the entire surface of the first substrate 10 by the CVD method and then etched to form the semiconductor layers 12R, 12G, and 12B.

Then, an opaque metal having good conductivity such as Cr, Mo, Ta, Cu, Ti, Al, or Al alloy is stacked on the first substrate 10 by sputtering and then etched to form semiconductor layers 12R, 12G, 12B The source electrodes 14R, 14G, and 14B and the drain electrodes 15R, 15G, and 15B are formed on the ohmic contact layer.

4B, an inorganic insulating material is deposited over the entire first substrate 10 on which the source electrodes 14R, 14G, and 14B and the drain electrodes 15R, 15G, and 15B are formed, An insulating layer 24 is formed. At this time, the first insulating layer 24 may have a thickness of about 4500 Å of SiO ₂ . Next, an R-color filter layer 17R, a G-color filter layer 17G, and a B-color filter layer 17B are formed on the R, G, and B pixels on the first insulating layer 24, respectively.

4C, the first substrate 10 on which the R-color filter layer 17R, the G color filter layer 17G, and the B color filter layer 17B are formed is patterned to form an organic The first insulating layer 24 and the second insulating layer 26 are etched to form the drain electrodes 15R, 15G, and 15B of the thin film transistor exposed The contact hole 29 is formed. At this time, the second insulating layer 26 may have a thickness of about 3 탆. Although the first insulating layer 24 and the second insulating layer 26 are simultaneously etched to form the contact holes 29 in the drawing, the first insulating layer 24 may be etched, The contact hole 26 may be etched to form the contact hole 29.

Next, pixel electrodes 21R, 21G and 21B made of a transparent conductive material such as ITO or IZO and a hydrogen absorbing layer 27 made of an oxide such as IGZO, IZO, ZnO or ITZO are formed on the second insulating layer 26 . At this time, the pixel electrodes 21R, 21G and 21B extend into the contact holes 29 and are electrically connected to the drain electrodes 15R, 15G and 15B of the driving TFT. Further, the pixel electrodes 21R, 21G, and 21B of the pixel are electrically insulated from the pixel electrodes 21R, 21G, and 21B of adjacent pixels.

Then, as shown in Fig. 4D, a bank layer 28 is formed between the pixel and the pixel. The bank layer 28 divides each pixel and prevents light of a specific color outputted from adjacent pixels from being mixed and output. The bank layer 28 is filled with a part of the contact hole 29 to reduce a step, Thereby preventing deterioration of the organic light emitting layer. The bank layer 28 may be formed by laminating and etching the inorganic insulating material CVD method, or may be formed by stacking organic insulating materials and then etching.

The organic light emitting portion 23 is formed over the entire first substrate 10 on which the bank layer 28 and the pixel electrodes 21R, 21G, and 21B are formed. The organic emission layer 23 may include an electron injection layer, an electron transport layer, a white organic emission layer, a positive hole transfer layer, and a hole injection layer. The white emission layer may include an R-organic emission material, a G- Or a structure in which an R-organic emitting layer, a G-organic emitting layer, and a G-organic emitting layer are laminated. The electron injecting layer, the electron transporting layer, the organic light emitting layer, the hole transporting layer, and the hole injecting layer may be formed of various materials that are currently used.

Then, a metal such as Ca, Ba, Mg, Al, or Ag is laminated on the organic light emitting portion 23 to form the common electrode 25. [

The pixel electrodes 21R, 21G and 21B are formed in the upper part of the thin film transistor and in the R, G and B pixels, and the hydrogen absorbing layer 27 is formed only in the upper part of the thin film transistor and not in the R, G and B pixels The pixel electrodes 21R, 21G and 21B and the hydrogen absorbing layer 27 are formed by a single mask process. The pixel electrodes 21R, 21G and 21B and the hydrogen absorbing layer 27 are formed by a single mask process, The forming process will be described in more detail.

Figs. 5A to 5E are views showing an example of a process of forming the pixel electrodes 21R, 21G, and 21B and the hydrogen absorbing layer 27. Fig. For convenience of explanation, only one of the R, G, and B pixels will be described.

5A, a metal oxide such as ITO or IZO and IGZO are continuously laminated on the second insulating layer 24 on which the contact hole is formed by sputtering or vapor deposition to form the metal oxide layer 21a and IGZO After the layer 27a is formed, a photoresist layer 80 is applied thereon, and a mask 85 is disposed on the photoresist layer 80 to irradiate light. At this time, the mask 85 is a diffraction mask or a half-tone mask. The mask 85 includes a transmissive area 85a, a transflective area 85b, and a blocking area 85c. Is irradiated.

Thereafter, as shown in FIG. 5B, the photoresist layer 80 irradiated with light is developed to form a first photoresist pattern 80a. At this time, the first photoresist pattern 80a has a different thickness depending on the position. That is, the first photoresist pattern 80a over the thin film transistor corresponding to the transmissive area 85a of the mask 85 is the thickest, and the area corresponding to the transflective area 85b of the mask 85 is partially removed And the first photoresist pattern 80a corresponding to the blocking region 85c of the mask 85 is completely removed and the lower IGZO layer 27a is exposed to the outside.

When the etching solution is applied in a state where the metal oxide layer 21a and the IGZO layer 27a are blocked by the first photoresist pattern 80a, the metal oxide layer 21a exposed to the outside, as shown in FIG. 5C, And the IGZO layer 27a are etched and removed to form the pixel electrode 21, and the IGZO layer 27a is disposed thereon.

Next, the first photoresist pattern 80a is subjected to acasing to form a second photoresist pattern 80b on the second insulating layer 24 as shown in FIG. 5D. At this time, the thin photoresist is removed by the ace, and the IGZO layer 27a of the pixel is exposed to the outside.

Thereafter, the IGZO layer 27a is etched with the etching solution in a state where the IGZO layer 27a is blocked by the second photoresist pattern 80b. As shown in FIG. 5E, the IGZO layer 27a The hydrogen absorbing layer 27 is formed on the upper portion of the thin film transistor except the pixel, and only the pixel electrode 21 is left in the pixel. At this time, the pixel electrode 21 and the hydrogen absorbing layer 27 are arranged as a double layer on the top of the thin film transistor.

As described above, in the present invention, when the pixel electrode 21 and the hydrogen absorbing layer 27 are formed, the pixel electrode 21 and the hydrogen absorbing layer 27 are formed by a single mask process using a diffraction mask or a halftone mask , The process can be simplified.

Figs. 6A and 6B are diagrams showing another example of a process of forming the pixel electrodes 21R, 21G, and 21B and the hydrogen absorbing layer 27. Fig.

6A, a metal oxide such as ITO or IZO and IGZO are continuously stacked on the second insulating layer 24 on which the contact hole is formed by sputtering or vapor deposition to form the metal oxide layer 21a and the IGZO layer The metal oxide layer 21a and the IGZO layer 27a are simultaneously etched by photolithography using a photoresist and a mask to form the pixel electrode 21. Then, At this time, the IGZO layer 27a is located above the pixel electrode 21. Then, a bank layer 28 is formed between the pixel and the pixel. At this time, the bank layer 28 locates the bank layer 28 on a part of the second insulating layer 24 and the IGZO layer 27a / pixel electrode 21. Since the bank layer 28 is formed between the pixel and the pixel, the thin film transistor is covered with the bank layer 28, and the IGZO layer 27a is exposed in the pixel.

6B, the IGZO layer 27a stacked by the etching solution is etched using the bank layer 28 as a blocking layer to form the IGZO layer 27a on the pixel electrode 21 inside the pixel, So that the pixel electrode 21 inside the pixel is exposed to the outside.

At this time, the IGZO layer 27a and the pixel electrode 21 above the thin film transistor blocked by the bank layer 28 are not etched, so that the IGZO layer 27a / pixel electrode 21 is formed above the thin film transistor, Only the pixel electrode 21 is formed.

As described above, the metal oxide layer 21a and the IGZO layer 27a are simultaneously etched by using one mask and the IGZO layer 27a is etched again by the bank layer 28. Thus, The pixel electrode 21 and the hydrogen absorbing layer 27 can be formed by one masking process.

7A and 7B are diagrams showing another example of a process of forming the pixel electrodes 21R, 21G, and 21B and the hydrogen absorbing layer 27. FIG. 21G and 21B of the organic electroluminescent display device of the second embodiment shown in Fig. 3 and the hydrogen absorbing layer 27 are shown.

7A, a metal oxide such as ITO or IZO and IGZO are continuously laminated on the second insulating layer 24 on which the contact hole is formed by sputtering or vapor deposition to form the metal oxide layer 21a and the IGZO layer The metal oxide layer 21a and the IGZO layer 27a are simultaneously etched by photolithography using a photoresist and a mask to form the pixel electrode 21. Then, At this time, the IGZO layer 27a is located above the pixel electrode 21. Then, a bank layer 28 is formed between the pixel and the pixel. At this time, the bank layer 28 locates the bank layer 28 on a part of the second insulating layer 24 and the IGZO layer 27a / pixel electrode 21. Since the bank layer 28 is formed between the pixel and the pixel, the thin film transistor is covered with the bank layer 28, and the IGZO layer 27a is exposed in the pixel.

7B, the exposed IGZO layer 27a is surface-treated with a plasma such as nitrogen, argon, helium, or hydrogen to form the hydrogen absorbing layer 27. Next, as shown in FIG. The hydrogen absorbing layer 27 is brought into electrical contact with the lower pixel electrode 21 to form the hydrogen absorbing layer 27 because the IGZO layer 27a is conductive and has conductivity when the IGZO layer 27a is surface- And the pixel electrode 21 constitute one anode.

Also in this method, since the metal oxide layer 21a and the IGZO layer 27a are simultaneously etched using the single mask and the IGZO layer 27a is subjected to the plasma surface treatment to form the hydrogen absorbing layer 27, Thus, the pixel electrode 21 and the hydrogen absorbing layer 27 can be formed by a single mask process.

4E, an adhesive layer 42 made of a thermosetting resin such as an epoxy compound, an acrylate compound, or an acrylic rubber is applied to the entire surface of the second substrate 50 The first substrate 10 and the second substrate 50 are pressed to form the first substrate 10 and the second substrate 50 in a state in which the second substrate 50 is positioned on the first substrate 10, The substrate 10 and the second substrate 50 are bonded together.

At this time, the adhesive or the adhesive film may be coated or attached on the first substrate 10, and then the second substrate 50 may be positioned thereon and then cemented.

The second substrate 50 may be made of glass, plastic, or a protective film such as a PS film, a PE film, a PEN film, or a polyimide film.

After the first substrate 10 and the second substrate 50 are bonded together as described above, the adhesive layer 42 is heated to a temperature of about 80-170 degrees to cure the adhesive layer 42. By curing the adhesive layer 42, it is possible to seal the organic electroluminescence display device and prevent moisture and the like from penetrating from the outside. In addition, the second substrate 50 functions as a sealing cap for sealing the organic light emitting display device, thereby protecting the organic light emitting display device.

As described above, in the present invention, the hydrogen absorbing layer made of IGZO is provided on the upper portion of the driving thin film transistor to absorb hydrogen diffused from the organic light emitting layer to the driving thin film transistor, thereby preventing hydrogen from penetrating into the oxide semiconductor layer of the driving thin film transistor It is possible to prevent defects due to deterioration of characteristics of the driving thin film transistor.

Further, in the present invention, since the pixel electrode and the hydrogen absorbing layer are formed by a single mask process, the process can be simplified and the cost can be reduced.

Although the organic electroluminescent display device has a specific structure of the organic electroluminescent display device in the above description, the present invention is not limited to the organic electroluminescent display device having such a specific structure.

For example, in the above description, the organic light emitting portion comprises the electron injection layer, the electron transporting layer, the organic light emitting layer, the hole transporting layer, and the hole injecting layer. However, the organic light emitting portion may be formed only as the organic light emitting layer, May be formed. In addition, the organic light emitting portion may be formed only of the organic light emitting layer and the hole injection layer, and various other configurations may be possible. In the above detailed description, IGZO is mainly described as a material for forming the hydrogen absorbing layer. However, the present invention is not limited to such IGZO but can be applied to a hydrogen absorbing layer which can prevent diffusion of hydrogen into the thin film transistor Various kinds of oxide semiconductors or other materials may be applied.

In other words, the organic electroluminescent display device of the present invention can be applied to all known organic electroluminescent display devices if it can include only a separate hydrogen absorbing layer structure for preventing penetration of hydrogen into the driving thin film transistor, which is an important point of the present invention .

10, 50: substrate 17R, 17G, 17B: color filter layer
21R, 21G, 21B: pixel electrode 23: organic light emitting portion
24, 26: insulating layer 25: common electrode
27: hydrogen absorbing layer 28: bank layer
42: Adhesive layer

Claims (12)

A first substrate and a second substrate including a plurality of pixels;
A thin film transistor formed on each pixel of the first substrate;
A color filter layer formed on each pixel;
An insulating layer formed on the color filter layer;
A pixel electrode for each pixel on the insulating layer;
A hydrogen absorbing layer formed on the thin film transistor to absorb hydrogen diffused into the thin film transistor;
An organic light emitting unit formed on the hydrogen absorbing layer and the pixel electrode to emit light; And
And a common electrode formed on the organic light emitting portion. The organic electroluminescent display device according to claim 1, wherein the hydrogen absorbing layer is made of an oxide. The hydrogen absorbing structure according to claim 2, wherein the hydrogen absorbing layer is made of a material selected from the group consisting of Indium Gallium Zinc Oxide (IGZO), Indium Tin Oxide (IZO), Zinc Oxide (ITO), and Indium Tin Zinc Oxide Organic electroluminescence display device. The organic light emitting display as claimed in claim 1, wherein the pixel electrode extends over the thin film transistor. The organic light emitting display device according to claim 1, wherein the hydrogen absorbing layer does not extend to a pixel. The organic light emitting display device according to claim 1, wherein the hydrogen absorbing layer extends to a pixel and has conductivity. The organic light emitting display according to claim 6, wherein the hydrogen absorbing layer has a work function larger than that of the pixel electrode. The thin film transistor according to claim 1,
A gate electrode formed on the first substrate;
A gate insulating layer formed on the gate electrode;
An oxide semiconductor layer formed on the gate insulating layer;
And a source electrode and a drain electrode formed on the oxide semiconductor layer. Providing a first substrate and a second substrate including a plurality of pixels;
Forming a thin film transistor on each pixel of the first substrate;
Forming a color filter layer on each pixel;
Forming a hydrogen absorbing layer for absorbing hydrogen diffused into the pixel electrode and the thin film transistor;
Forming a bank layer between pixels;
Forming an organic light emitting portion for emitting light on the pixel electrode and the hydrogen absorbing layer;
Forming a common electrode on the organic light emitting portion; And
And bonding the first substrate and the second substrate to each other. 10. The method of claim 9, wherein forming the pixel electrode and the hydrogen absorbing layer comprises:
Sequentially stacking a metal oxide and an oxide semiconductor on a first substrate and forming a photoresist layer thereon;
Developing the photoresist layer using a diffraction mask or a halftone mask to form a first photoresist pattern having different thicknesses;
Forming a pixel electrode by simultaneously etching the metal oxide and the oxide semiconductor using the first photoresist pattern;
Forming a second photoresist pattern by aging the first photoresist pattern; And
And etching the oxide semiconductor of the pixel using the second photoresist pattern to form a hydrogen absorbing layer on the thin film transistor. 10. The method of claim 9, wherein forming the pixel electrode and the hydrogen absorbing layer comprises:
Sequentially stacking the metal oxide and the oxide semiconductor on the first substrate, and etching the metal oxide and the oxide semiconductor all at once by a photolithography process;
Forming a bank layer between the pixels to expose the oxide semiconductor of the pixel between the bank layers; And
And removing the oxide semiconductor of the pixel by etching the exposed oxide semiconductor. 10. The method of claim 9, wherein forming the pixel electrode and the hydrogen absorbing layer comprises:
Sequentially stacking the metal oxide and the oxide semiconductor on the first substrate, and etching the metal oxide and the oxide semiconductor all at once by a photolithography process;
Forming a bank layer between the pixels to expose the oxide semiconductor of the pixel between the bank layers; And
And exposing the exposed oxide semiconductor to a plasma to form an oxide semiconductor of a pixel as a conductive layer.

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