KR101788397B1

KR101788397B1 - Organic light emitting display device

Info

Publication number: KR101788397B1
Application number: KR1020150134923A
Authority: KR
Inventors: 김호진; 유충근; 이용백
Original assignee: 엘지디스플레이 주식회사
Priority date: 2015-09-23
Filing date: 2015-09-23
Publication date: 2017-11-15
Also published as: KR20170035698A

Abstract

The organic electroluminescent display device of the present invention is characterized in that a transparent oxide layer (IZO, IGZO, etc.) constituting the active layer of the oxide TFT is formed below the inorganic film of the thin- ) Are interposed.
According to the present invention, it is possible to improve the image quality deficiency by blocking the influence of the active layer due to gas, ions, or the like generated in the inorganic film of silicon nitride film or silicon oxide film at high temperature / high humidity.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an organic light-

The present invention relates to an organic light emitting display, and more particularly, to an organic light emitting display using an oxide thin film transistor.

In recent years, there has been a growing interest in information display and a demand for a portable information medium has increased, and a lightweight flat panel display (FPD) that replaces a cathode ray tube (CRT) And research and commercialization are being carried out.

In the field of flat panel displays, a liquid crystal display device (LCD), which is light and consumes less power, has attracted the greatest attention, but a liquid crystal display device is not a light emitting device but a light receiving device. ) And a viewing angle. Therefore, a new display device capable of overcoming such drawbacks is actively developed.

Since the organic light emitting display device, which is one of the new display devices, is self-emitting type, the viewing angle and the contrast ratio are superior to the liquid crystal display device. In addition, since a backlight is not required, it is possible to make a light-weight thin type, and it is also advantageous in terms of power consumption. It has the advantage of being able to drive DC low voltage and has a fast response speed.

Hereinafter, the basic structure and operating characteristics of the organic light emitting display will be described in detail with reference to the drawings.

1 is a diagram for explaining the principle of light emission of a general organic light emitting diode.

In general, an organic light emitting display device includes an organic light emitting diode as shown in FIG.

The organic light emitting diode includes an anode 18 as a pixel electrode, a cathode 28 as a common electrode, and organic layers 30a, 30b, 30c, 30d and 30e formed therebetween.

The organic layers 30a, 30b, 30c, 30d and 30e are formed of a hole transport layer (HTL) 30b, an electron transport layer (ETL) 30d, a hole transport layer 30b and an electron transport layer And an emission layer (EML) 30c interposed between the emission layers 30a and 30d.

In this case, a hole injection layer (HIL) 30a is interposed between the anode 18 and the hole transport layer 30b to enhance the emission efficiency, and electrons are injected between the cathode 28 and the electron transport layer 30d. An electron injection layer (EIL) 30e is interposed.

When the positive and negative voltages are applied to the anode 18 and the cathode 28, the organic light emitting diode having the above structure passes through the hole transporting layer 30b and the electron transporting layer 30d One electron is moved to the light emitting layer 30c to form an exciton, and light is generated when the exciton transitions from an excited state to a ground state, that is, a stable state.

An organic light emitting display displays an image by arranging sub-pixels having organic light emitting diodes of the above-described structure in a matrix form and selectively controlling the sub-pixels with a data voltage and a scan voltage.

At this time, the organic light emitting display device is divided into an active matrix method using a thin film transistor (TFT) as a passive matrix type or a switching element. The active matrix method selectively turns on the active element TFT to select the sub-pixel and maintains the emission of the sub-pixel with the voltage held in the storage capacitor.

A typical organic light emitting display device driven in this manner includes a substrate on which a plurality of TFTs and organic light emitting diodes are formed, and an encapsulation layer formed on the substrate.

Meanwhile, conventional mobile and wearable organic light emitting display devices mainly use an amorphous silicon thin film or a polycrystalline silicon thin film as an active layer of a TFT, but in the future, oxide thin film transistors (TFTs) using oxide semiconductors Is expected to be applied.

However, when an oxide TFT is used as an active device, gases or ions generated in an inorganic film of a silicon nitride film (SiNx) used in an encapsulating layer under a high temperature / high humidity environment are used as an active layer of an IGZO (Indium Gallium Zinc Oxide), which causes bad image quality such as abnormal luminescence phenomenon, and improvement is needed.

SUMMARY OF THE INVENTION The present invention provides an organic electroluminescent display device in which the influence of an oxide TFT due to a gas or an ion generated in a thin film encapsulation layer is minimized in an organic light emitting display device using an oxide TFT There is a purpose.

Other objects and features of the present invention will be described in the following description of the invention and the claims.

According to an aspect of the present invention, there is provided an organic light emitting display including a TFT including an active layer composed of an oxide semiconductor, a TFT including an active layer electrically connected to the TFT, And a capping layer provided on an upper surface of the substrate of the pixel portion having the light emitting diode and the organic light emitting diode.
At this time, an organic light emitting display device according to an embodiment of the present invention includes an inorganic film covering at least a transparent oxide layer made of the oxide semiconductor and the transparent oxide layer on the capping layer, And a thin film encapsulation layer formed by laminating an organic film provided on the inorganic film.

At this time, the transparent oxide layer may be composed of IZO or IGZO constituting the active layer of the oxide TFT.

The capping layer may be provided on an entire surface of the substrate of the pixel portion, and the transparent oxide layer may be provided on the upper surface of the capping layer.

The capping layer may be provided to surround the pixel portion.

The transparent oxide layer may have a cap shape to enclose the capping layer, and the inorganic film may have a cap shape to enclose the transparent oxide layer.

The organic light emitting display device according to an embodiment of the present invention may further include a transparent oxide layer made of the oxide semiconductor between the inorganic film and the organic film.

According to another aspect of the present invention, there is provided an organic light emitting display including a thin-film encapsulating layer surrounding the capping layer and including an inorganic film and an organic film alternately stacked at least once, And is replaced with a transparent oxide layer composed of an oxide semiconductor.

As described above, in the organic light emitting display according to an embodiment of the present invention, a transparent oxide layer made of IZO or IGZO is interposed under the inorganic film of the thin-film encapsulation layer to form an oxide The influence of the TFT is blocked. According to this, the present invention provides an effect to improve the image quality defect.

In the organic light emitting display according to another embodiment of the present invention, the inorganic film of the thin film sealing layer is replaced with a transparent oxide layer such as IZO or IGZO. In this case, the influence of the oxide TFT There is an advantage that it can be fundamentally blocked.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram for explaining a principle of light emission of a general organic light emitting diode. FIG.
2 is a block diagram schematically showing an organic light emitting display device according to the present invention.
FIG. 3 is an exemplary diagram showing a circuit configuration for a sub-pixel of an organic light emitting display device. FIG.
4 is a perspective view schematically showing a structure of an organic light emitting display according to a first embodiment of the present invention.
5 is a cross-sectional view illustrating an exemplary structure of an organic light emitting display device according to a first embodiment of the present invention.
6 is a cross-sectional view showing a part of the organic light emitting display device shown in FIG. 5 in detail;
7A and 7B are cross-sectional views illustrating an example of an encapsulation structure of an organic light emitting display device according to a first embodiment of the present invention.
8A to 8C are cross-sectional views illustrating another example of the sealing structure of the organic light emitting display device according to the first embodiment of the present invention.
9 is a cross-sectional view illustrating an exemplary structure of an organic light emitting display device according to a second embodiment of the present invention.
10 is a cross-sectional view illustrating an exemplary structure of an organic light emitting display device according to a third embodiment of the present invention.
11A and 11B are cross-sectional views illustrating an example of an encapsulation structure of an organic light emitting display device according to a third embodiment of the present invention.

Hereinafter, preferred embodiments of the organic light emitting display according to the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention and the manner of achieving them will become apparent with reference to the embodiments described in detail below with reference to the accompanying drawings. It should be understood, however, that the invention is not limited to the disclosed embodiments, but is capable of many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, To fully disclose the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout the specification. The dimensions and relative sizes of the layers and regions in the figures may be exaggerated for clarity of illustration.

It will be understood that when an element or layer is referred to as being another element or "on" or "on ", it includes both intervening layers or other elements in the middle, do. On the other hand, when a device is referred to as "directly on" or "directly above ", it does not intervene another device or layer in the middle.

The terms spatially relative, "below," "lower," "above," "upper," and the like, And may be used to easily describe the correlation with other elements or components. Spatially relative terms should be understood to include, in addition to the orientation shown in the drawings, terms that include different orientations of the device during use or operation. For example, when inverting an element shown in the figures, an element described as "below" or "beneath" of another element may be placed "above" another element. Thus, the exemplary term "below" can include both downward and upward directions.

The terminology used herein is for the purpose of describing embodiments only and is not intended to be limiting of the invention. In the present specification, the singular form includes plural forms unless otherwise specified in the specification. &Quot; comprise "and / or" comprising ", as used in the specification, means that the presence of stated elements, Or additions.

2 is a block diagram schematically showing an organic light emitting display device according to the present invention.

2, an organic light emitting display according to an exemplary embodiment of the present invention includes an image processor 115, a data converter 114, a timing controller 113, a data driver 112, a gate driver 111, 116 may be included.

The image processing unit 115 performs various image processing such as setting a gamma voltage to realize the maximum luminance according to the average image level using the RGB data signals RGB, and then outputs RGB data signals RGB. The image processor 115 generates a driving signal including at least one of the RGB data signal RGB as well as the vertical synchronizing signal Vsync, the horizontal synchronizing signal Hsync, the data enable signal DES and the clock signal CLK Output.

The timing controller 113 receives one or more of the vertical synchronization signal Vsync, the horizontal synchronization signal Hsync, the data enable signal DES and the clock signal CLK from the image processing unit 115 or the data conversion unit 114 And is supplied with a drive signal. The timing control section 113 generates a gate timing control signal GCS for controlling the operation timing of the gate driving section 111 and a data timing control signal DCS for controlling the operation timing of the data driving section 112, .

The timing controller 113 outputs the data signal DATA corresponding to the gate timing control signal GCS and the data timing control signal DCS.

The data driver 112 samples and latches the data signal DATA supplied from the timing controller 113 in response to the data timing control signal DCS supplied from the timing controller 113, And outputs it. The data driver 112 outputs the converted data signal DATA through the data lines DL1 to DLm. The data driver 112 is formed in the form of an IC (Integrated Circuit).

The gate driving unit 111 outputs the gate signal while shifting the level of the gate voltage in response to the gate timing control signal GCS supplied from the timing control unit 113. [ The gate driver 111 outputs a gate signal through the gate lines GL1 to GLn. The gate driver 111 may be formed in the form of an IC or a gate-in-panel (GIP) method in the display panel 116.

The display panel 116 may be implemented in a sub-pixel structure including, for example, a red sub-pixel SPr, a green sub-pixel SPg and a blue sub-pixel SPb. That is, one pixel P is composed of RGB sub-pixels SPr, SPg, SPb. However, the present invention is not limited thereto, and may include a white sub-pixel.

3 is an exemplary diagram illustrating a circuit configuration for a sub-pixel of an organic light emitting display device.

In this case, the sub-pixel shown in FIG. 3 is configured as a 2T (Transistor) 1C (Capacitor) structure including a switching transistor, a driving transistor, a capacitor, and an organic light emitting diode. However, the present invention is not limited to this, and when a compensation circuit is added, it can be configured in various ways such as 3T1C, 4T2C, 5T2C, and the like.

3, the organic light emitting display includes a gate line GL arranged in a first direction and a data line DL arranged apart from each other in a second direction crossing the first direction and a driving power line VDDL Sub-pixel region is defined by the sub-pixel region.

One sub-pixel may include a switching transistor SW, a driving transistor DR, a capacitor Cst, a compensation circuit CC and an organic light emitting diode OLED.

The organic light emitting diode OLED operates to emit light in accordance with the driving current generated by the driving transistor DR.

The switching transistor SW operates in response to a gate signal supplied through the gate line GL so that a data signal supplied through the data line DL is stored as a data voltage in the capacitor Cst.

The driving transistor DR operates so that a driving current flows between the driving power supply line VDDL and the ground wiring GND in accordance with the data voltage stored in the capacitor Cst.

The compensation circuit CC compensates the threshold voltage of the driving transistor DR and the like. The compensation circuit CC may consist of one or more transistors and capacitors. The configuration of the compensation circuit (CC) is very various, and a detailed illustration and description thereof are omitted.

The organic light emitting display having such a sub-pixel structure may be implemented by a top emission method, a bottom emission method, or a dual emission method depending on a direction in which light is emitted.

The top emission type organic light emitting display device has an advantage that the aperture ratio can be increased as compared with the backlight emission method in which light is emitted in the direction of the substrate on which the pixels are arranged, .

The organic light emitting display device of the top emission type includes an anode formed on a lower portion of an organic layer including a light emitting layer and a cathode formed on an organic layer through which light is transmitted.

4 is a perspective view schematically showing the structure of an organic light emitting display according to a first embodiment of the present invention. 4 illustrates an organic light emitting display device in which a flexible circuit board is fastened.

5 is a cross-sectional view illustrating an exemplary structure of an organic light emitting display device according to a first embodiment of the present invention, and is a cross-sectional view taken along line A-A of FIG.

6 is a cross-sectional view showing a part of the organic light emitting display device shown in FIG. 5, and shows a specific cross section of the panel part and the thin film sealing layer. In the panel portion, a plurality of sub-pixels are arranged in a matrix as viewed in a plane. Each sub-pixel includes a red sub-pixel SPr emitting red light, a green sub-pixel SPg emitting green light, And a blue sub-pixel SPb which emits light. In FIG. 6, for the sake of convenience, only three sub-pixels are shown for each color.

Referring to FIG. 4, the organic light emitting display according to the first embodiment of the present invention includes a panel assembly 100 for displaying an image and a flexible circuit board 150 connected to the panel assembly 100.

The panel assembly 100 is provided on the substrate 101 and includes a panel unit 110 divided into an active area AA and a pad area PA and an active area AA disposed on the panel unit 110 while covering the active area AA. And a thin film encapsulation layer 140.

The active area AA includes a pixel part AAa in which a plurality of sub-pixels are disposed and actually displays an image, and an outer area formed in the outer part of the pixel part AAa to transmit a signal applied from the outside to the pixel part AAa. And the thin film encapsulation layer 140 is formed on the panel part 110 while covering a part of the pixel part AAa and the outer frame part AAb.

At this time, the panel part 110 exposed without being covered by the thin film sealing layer 140 constitutes a pad part PA where the pad is formed.

The substrate 101 may be a flexible flexible substrate. The flexible substrate may be formed of one or more materials selected from the group consisting of polyethylene ether phthalate (PET), polyethyelenenaphthalate (PEN), polycarbonate (PC), polyallylate, polyetherimide (PEI), polyethersulphone ), Polyimide, and the like can be used as a material having excellent heat resistance and durability. However, the present invention is not limited thereto, and various flexible materials may be used.

In the case of the back light emission type in which an image is realized in the direction of the substrate 101, the substrate 101 must be formed of a transparent material. However, in the case of the top emission type in which the image is formed in the direction opposite to the substrate 101, the substrate 101 does not necessarily have to be formed of a transparent material. In this case, the substrate 101 can be formed of metal. When the substrate 101 is formed of metal, the substrate 101 may include at least one metal selected from the group consisting of carbon, iron, chromium, manganese, nickel, titanium, molybdenum and stainless steel, no.

On the upper surface of the substrate 101, a panel portion 110 is disposed. The term " panel unit 110 " referred to in this specification collectively refers to an organic light emitting diode and a TFT array for driving the same, and includes an active area AA for displaying an image and a pad area PA for displaying an image It means.

At this time, although not shown, pixels are arranged in a matrix form in the active area AA, and driving elements and other parts such as a scan driver and a data driver for driving the pixels are located outside the active area AA.

On the upper surface of the substrate 101, a thin film encapsulation layer 140 is formed to cover a part of the panel part 110. The organic light emitting diode included in the panel unit 110 is made of an organic material and easily deteriorated by external moisture or oxygen. Therefore, the panel unit 110 must be sealed to protect the organic light emitting diode. The thin film encapsulation layer 140 has a structure in which a plurality of inorganic films and organic films are alternately laminated by a means for sealing the panel part 110. By sealing the panel part 110 with the thin film sealing layer 140 instead of the sealing substrate, the organic light emitting display device can be made thin and flexible.

At this time, the portion exposed by the thin film encapsulation layer 140 not covered constitutes the above-described pad region PA.

An integrated circuit chip (not shown) may be mounted on the pad area PA of the panel assembly 100 by a chip on glass (COG) method.

On the flexible circuit board 150, electronic elements (not shown) for processing a driving signal are mounted by a chip on film (COF) method, and an external signal is supplied to the flexible circuit board 150 A connector (not shown) may be installed.

The flexible circuit board 150 may be folded rearward of the panel assembly 100 so that the flexible circuit board 150 faces the backside of the panel assembly 100. At this time, an anisotropic conductive film (not shown) may be used to electrically connect the terminal portion of the panel portion 110 and the connection portion of the flexible circuit board 150 with each other.

5 and 6, the thin film encapsulation layer 140 will be described in detail. For example, a capping layer 129 is formed on the upper surface of the substrate 101 on which the organic light emitting diode 102 is formed, A first protective film 140a, an organic film 140b and a second protective film 140c are sequentially formed as sealing means to constitute a thin film encapsulating layer 140. [ However, the number of the inorganic films and the organic films constituting the thin film encapsulation layer 140 is not limited thereto.

At this time, a transparent oxide layer 119 according to the present invention is formed on the capping layer 129, and a thin film encapsulating layer 140 composed of multiple layers is formed thereon.

Since the primary protective film 140a is formed of an inorganic insulating film and stack coverage is not good due to the lower TFT step difference, the organic film 140b positioned on the upper side serves as a planarizing layer, Is not affected by the step difference caused by the lower film. Further, since the thickness of the organic film 140b made of the polymer is sufficiently thick, cracks due to foreign matter can be compensated.

A multilayer protective film 145 is placed opposite to the front surface of the substrate 101 including the secondary protective film 140c and the transparent film between the substrate 101 and the protective film 145 is transparent, Sensitive adhesive 146 is interposed.

On the protective film 145, a polarizing plate (not shown) may be attached to prevent reflection of light incident from the outside.

Referring to FIG. 6, each sub-pixel SPr, SPg, SPb includes an organic light emitting diode and an electronic device electrically connected to the organic light emitting diode. The electronic device may include at least two or more TFTs, storage capacitors, and the like. The electronic device is electrically connected to the wirings and is driven by receiving an electrical signal from a driving element outside the panel portion. The array of electronic elements and wirings electrically connected to the organic light emitting diode is referred to as a TFT array.

6, only the driving TFTs for driving the organic light emitting diodes and the organic light emitting diodes are illustrated for each of the sub-pixels SPr, SPg, and SPb. However, the present invention is not limited thereto, A plurality of TFTs, a storage capacitor, and various wirings may be further included.

The TFT shown in FIG. 6 is a top gate type and sequentially includes an active layer 124, a gate electrode 121, and source / drain electrodes 122 and 123. The present invention is not limited to the top gate type of the TFT shown in the drawings, but various types of TFTs can be employed.

The organic light emitting diode includes a first electrode 118, an organic compound layer 130, and a second electrode 128.

Here, although not shown in detail, the organic compound layer 130 may further include various organic layers for efficiently transporting carriers of holes or electrons to the light-emitting layer in addition to the light-emitting layer that actually emits light.

The organic layers may include a hole injecting layer and a hole transporting layer disposed between the first electrode 118 and the light emitting layer, and an electron injecting layer and an electron transporting layer disposed between the second electrode 128 and the light emitting layer.

A first electrode 118 made of transparent oxide is formed on the substrate 101 made of plastic or stainless steel and the organic compound layer 130 and the second electrode 128 are sequentially stacked on the first electrode 118. [ .

Based on such a structure, the holes injected from the first electrode 118 and the electrons injected from the second electrode 128 are coupled to each other in the light emitting layer via the transport layer for transport, and then moved to a low energy level And light having a wavelength corresponding to the energy difference in the light emitting layer is generated.

At this time, the light emitting layer may more specifically include a red light emitting layer, a green light emitting layer, and a blue light emitting layer in order to emit white light.

The TFT basically includes a switching transistor and a driving transistor.

Although not shown, the switching transistor is connected to a scan line and a data line, and transmits a data voltage input to the data line to the driving transistor according to a switching voltage input to the scan line. The storage capacitor is connected to the switching transistor and the power supply line, and stores a voltage corresponding to a difference between a voltage received from the switching transistor and a voltage supplied to the power supply line.

The driving transistor is connected to the power supply line and the storage capacitor to supply the organic light emitting diode with an output current proportional to the square of the difference between the voltage stored in the storage capacitor and the threshold voltage, and the organic light emitting diode emits light by the output current.

The driving transistor includes an active layer 124 and a gate electrode 121 and source and drain electrodes 122 and 123 and a first electrode 118 of the organic light emitting diode may be connected to a drain electrode 123 of the driving transistor. have. That is, the driving transistor includes a buffer layer 115a formed on the substrate 101, an active layer 124 formed on the buffer layer 115a, a first insulating layer 115b formed on the substrate 101 on which the active layer 124 is formed, A gate electrode 121 formed on the first insulating layer 115b and a second insulating layer 115c formed on the substrate 101 on which the gate electrode 121 is formed and a second insulating layer 115c, And source / drain electrodes 122 and 123 electrically connected to the source / drain regions of the active layer 124 through the source / drain electrodes.

The buffer layer 115a may be formed of a single layer or a plurality of layers and may be formed to protect a TFT formed in a subsequent process from impurities such as alkali ions flowing out from the substrate 101. [

The active layer 124 may be formed of an oxide semiconductor.

When the active layer 124 is formed using an oxide semiconductor, it has a merit that it can be applied to a large-area display while ensuring uniform characteristics while satisfying high mobility and constant current test conditions.

In recent years, interest and activity have been concentrated on transparent electronic circuits. An oxide TFT using an oxide semiconductor as an active layer 124 has an advantage of being used in a transparent electronic circuit since it has high mobility and can be manufactured at a low temperature have.

For example, in the present invention, an IGZO semiconductor active layer 124 containing heavy metals such as indium (In) and gallium (Ga) can be formed on zinc oxide.

The gate electrode 121 may be formed of an aluminum-based metal such as aluminum (Al) or an aluminum alloy, a copper-based metal such as copper (Cu) or a copper alloy, molybdenum (Mo) And a low resistance opaque conductive material such as chromium (Cr), tantalum (Ta), and titanium (Ti) can be used. However, they may have a multilayer structure including two conductive films having different physical properties.

A first insulating layer (115b) and the second insulation layer (115c) is in a dual layer made of a single layer, or a silicon nitride film and a silicon oxide film made of an inorganic insulating material such as silicon nitride (SiNx) or silicon oxide (SiO ₂₎ Lt; / RTI >

The source electrode 122 and the drain electrode 123 may be formed of an aluminum-based metal such as aluminum or an aluminum alloy, a copper-based metal such as copper or a copper alloy, Low resistance opaque conductive materials such as tantalum and titanium can be used. However, they may have a multilayer structure including two conductive films having different physical properties.

However, the configuration of the sub-pixels SPr, SPg, SPb is not limited to the above-described example, and can be variously modified.

The third insulating layer 115d may be formed on the substrate 101 on which the driving transistor is formed and the third insulating layer 115d may be formed of an inorganic insulating material such as a silicon nitride film or a silicon oxide film.

At this time, the drain electrode 123 of the driving transistor is electrically connected to the first electrode 118 through the second contact hole formed in the third insulating layer 115d.

The first electrode 118 may be formed of a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO) or a reflective conductive material such as aluminum, silver or an alloy thereof. Lt; / RTI >

A partition wall 115e is formed at the boundary of each pixel region above the third insulating layer 115d. The barrier rib 115e divides each pixel region to prevent light of a specific color outputted from an adjacent pixel region from being mixed and outputted.

The organic compound layer 130 of the organic light emitting diode described above is formed on the first electrode 118 between the barrier ribs 115e. However, the present invention is not limited thereto, and the organic compound layer 130 may be formed on the entire surface of the substrate 101.

A second electrode 128 is formed on the organic compound layer 130 in the display area. The second electrode 128 may be formed of a reflective conductive material including calcium (Ca), barium (Ba), magnesium (Mg), aluminum, silver or the like or a transparent conductive material such as ITO or IZO have.

A capping layer 129 made of an organic material such as a polymer is formed over the entire substrate 101 of the pixel portion on the substrate 101 on which the second electrode 128 is formed.

The capping layer 129 may have a specific refractive index in the case of the front emission type and may improve light emission by collecting light. In the case of the back emission type, It plays a role.

The capping layer 129 may serve as one optical control layer. The capping layer 129 may increase the reflectivity at the interface between the capping layer 129 and the exterior by controlling the refractive index difference with the outside. This increase in reflectance allows the capping layer 129 to exhibit a micro-cavity effect at a particular wavelength. At this time, the capping layer 129 may have different thicknesses for the sub-pixels SPr, SPg, and SPb.

On the capping layer 129, a transparent oxide layer 119 according to the present invention is formed, and a thin film encapsulating layer 140 composed of multiple layers is formed thereon.

At this time, when the oxide TFT is used as described above, an inorganic film such as a silicon nitride film or a silicon oxide film of the thin film encapsulating layer 140, that is, a gas or the like generated at high temperature / high humidity in the primary and secondary protective films 140a and 140c Ion affects the IGZO which is the active layer 124 of the oxide TFT, causing an image quality defect. A transparent oxide layer 119 made of IZO or IGZO or the like which constitutes the active layer 124 of the oxide TFT is formed under the thin film encapsulation layer 140 and specifically below the primary and secondary protective films 140a and 140c, Is further formed. This is because gas or ions generated in the silicon nitride film, the silicon oxide film, or the like used for the primary and secondary protective films 140a and 140c penetrate and influence the IGZO which is the active layer 124 of the oxide TFT, A transparent oxide layer 119 such as IZO or IGZO is added to the lower portion of the first and second protective films 140a and 140c to prevent gas or ions from being diffused toward the oxide TFT. The IZO or IGZO may be formed on the entire surface of the capping layer 129 through sputtering.

The transparent oxide layer 119 of the present invention may be formed to have substantially the same stepped portion according to the step of the capping layer 129 under the capping layer 129. That is, the organic compound layer 130 and the second electrode 128, the capping layer 129, and the transparent oxide layer 119 on the first electrode 118 all have stepped portions according to a step formed by the barrier rib 115e .

Also, the first protective film 140a on the transparent oxide layer 119 is formed to have substantially the same step, and the organic film 140b on the first protective film 140a is formed on the entire surface of the substrate 101 as a planarizing film. That is, the organic film 140b may be formed such that the upper surface thereof is substantially planarized. Therefore, the secondary protective film 140c is not affected by the step difference due to the lower film.

Referring again to FIG. 5, the transparent oxide layer 119 may be formed on the entire surface of the active region of the pixel portion AAa except for the outer portion AAb so as to have the same width as the capping layer 129. The first protective layer 140a may be formed to cover the organic light emitting diode 102, the capping layer 129, and the transparent oxide layer 119 in a hat shape. That is, in order to seal the active region of the pixel portion AAa, the first protective film 120 is formed on the transparent oxide layer 119 so as to cover not only the upper surface of the organic light emitting diode 102, the capping layer 129, and the transparent oxide layer 119, The cap 140a may be formed in a hat shape.

The organic layer 140b may be formed on the organic layer 140b and the secondary protective layer 140c may be formed to cover the organic layer 140b. However, the present invention is not limited to the above-described sealing structure, and the capping layer 129 and the transparent oxide layer 119 may also be formed to have a hat shape like the first and second protective films 140a and 140c (See the second embodiment of the present invention to be described later).

7A and 7B are cross-sectional views illustrating an example of an encapsulation structure of an organic light emitting display according to a first embodiment of the present invention.

7A illustrates an example in which the thin film encapsulation layer 140 has a three-layer structure including a first protective film 140a, an organic film 140b, and a second protective film 140c. 7B is a sectional view showing a state in which the first protective film 140a, the first organic film 140b, the second protective film 140c, the second organic film 140d and the third protective film 140e are formed of the thin film encapsulating layer 140 ' 5-layer structure is shown as an example.

Referring to FIGS. 7A and 7B, the transparent oxide layer 119 according to the first embodiment of the present invention described above is formed of the thin film encapsulation layers 140 and 140 'regardless of the number of layers of the thin encapsulation layers 140 and 140' ', That is, between the capping layer 129 and the primary protective film 140a.

However, the present invention is not limited thereto, and the transparent oxide layer of the present invention can be interposed before, after, or both before and after the primary protective film.

8A to 8C are cross-sectional views illustrating another example of the sealing structure of the organic light emitting display device according to the first embodiment of the present invention.

As described above, the transparent oxide layer 119 of the present invention is formed on the transparent oxide layer 119 before or after the first protective film 140a (see FIGS. 7A and 7B) or after the second protective film 140a (Refer to FIG. 8B) of the second side 140c.

Referring to FIG. 8A, when the transparent oxide layer 119 is interposed after the first protective layer 140a, the first protective layer 140a is located between the first protective layer 140a and the organic layer 140b. Referring to FIG. 8B, when the transparent oxide layer 119 is interposed before the second protective layer 140c, the first protective layer 140c is located between the organic layer 140b and the second protective layer 140c.

In addition, the transparent oxide layers 119a and 119b of the present invention can be interposed both before and after the primary protective film 140a (see FIG. 8C). 8C, when the transparent oxide layers 119a and 119b are interposed both before and after the first protective film 140a, a first transparent oxide layer (not shown) is formed between the capping layer 129 and the first protective film 140a And the second transparent oxide layer 119b is positioned between the first protective film 140a and the organic film 140b.

The present invention is also applicable to the case where the capping layer and the transparent oxide layer are formed so as to surround the active region of the pixel portion, which will be described in detail through the following second embodiment of the present invention.

FIG. 9 is a cross-sectional view illustrating an exemplary structure of an organic light emitting display according to a second embodiment of the present invention. Referring to FIG.

The organic light emitting display according to the second embodiment of the present invention includes a panel assembly for displaying an image and a flexible circuit board connected to the panel assembly in substantially the same manner as in the first embodiment.

The panel assembly is provided on the substrate, and includes a panel part divided into an active area and a pad area, and a thin film sealing layer provided on the panel part while covering the active area.

9, the active region includes a pixel portion AAa in which a plurality of sub-pixels are arranged and displays an image, and a signal portion formed in the periphery of the pixel portion AAa to receive a signal applied from the outside in the pixel portion AAa And the thin film encapsulation layer 240 is formed on the panel part while covering a part of the pixel part AAa and the outer frame part AAb.

At this time, the panel portion which is not covered by the thin film encapsulation layer 240 and is exposed forms a pad portion where the pad is formed.

A panel portion is disposed on the upper surface of the substrate 201.

At this time, although not shown, pixels are arranged in a matrix form in the active area, and driving elements and other parts such as a scan driver and a data driver for driving the pixels are located outside the active area.

On the upper surface of the substrate 201, a thin film encapsulation layer 240 is formed to cover the panel part. The thin film encapsulation layer 240 has a structure in which a plurality of inorganic films and organic films are alternately laminated by means of sealing the panel part.

At this time, the portions that are not covered by the thin film encapsulation layer 240 and are exposed form the above-described pad region.

The capping layer 229 is formed on the upper surface of the substrate 201 on which the organic light emitting diode 202 is formed and the first protective film 240a and the second protective film 240b are formed as sealing means on the capping layer 229, An organic film 240b and a secondary protective film 240c are sequentially formed to constitute the thin film encapsulation layer 240. [ However, the number of inorganic films and organic films constituting the thin film encapsulation layer 240 is not limited thereto.

At this time, a transparent oxide layer 219 according to the present invention is formed on the capping layer 229, and a thin-film encapsulating layer 240 composed of multiple layers is formed thereon.

Since the primary protective film 240a is made of an inorganic insulating film and the stacking coverage is not good due to the lower TFT step difference, the organic protective film 240b located on the upper part serves as a planarizing layer, Is not influenced by the stepped portion. Further, since the thickness of the organic film 240b made of the polymer is sufficiently thick, cracks due to foreign matter can also be compensated.

A multilayer protective film 245 is placed opposite to the front surface of the substrate 201 including the secondary protective film 240c and a transparent film is formed between the substrate 201 and the protective film 245, And a pressure-sensitive adhesive (246)

On the protective film 245, a polarizing plate (not shown) may be attached to prevent reflection of light incident from the outside.

Although not shown, each sub-pixel includes an electronic device electrically connected to the organic light emitting diode and the organic light emitting diode, similar to the first embodiment of the present invention described above. The electronic device may include at least two or more TFTs, storage capacitors, and the like. The electronic device is electrically connected to the wirings and is driven by receiving an electrical signal from a driving element outside the panel portion.

The organic light emitting diode includes a first electrode, an organic compound layer, and a second electrode.

In this manner, a first electrode made of transparent oxide is formed on a substrate 201 made of plastic or stainless steel, and an organic compound layer and a second electrode are sequentially stacked on the first electrode.

The TFT basically includes a switching transistor and a driving transistor.

As described above, the driving transistor includes an active layer, a gate electrode, and a source / drain electrode, and a first electrode of the organic light emitting diode may be connected to a drain electrode of the driving transistor. That is, the driving transistor includes a buffer layer formed on the substrate 201, an active layer formed on the buffer layer, a first insulating layer formed on the substrate 201 on which the active layer is formed, a gate electrode formed on the first insulating layer, And a source / drain electrode formed on the second insulating layer and electrically connected to a source / drain region of the active layer through the first contact hole.

The active layer may be formed of an oxide semiconductor.

For example, in the present invention, an active layer of an IGZO semiconductor containing a heavy metal such as indium and gallium in zinc oxide can be formed.

However, the structure of such a sub-pixel is not limited to the above-described example, and can be variously modified.

A third insulating layer may be formed on the substrate 201 on which the driving transistor is formed, and the third insulating layer may be formed of an inorganic insulating material such as a silicon nitride film or a silicon oxide film.

At this time, the drain electrode of the driving transistor is electrically connected to the first electrode through the second contact hole formed in the third insulating layer.

A partition is formed at the boundary of each pixel region above the third insulating layer. The barrier ribs are for preventing each pixel region from being mixed and outputting light of a specific color outputted from the adjacent pixel region.

The organic compound layer of the organic light emitting diode described above is formed on the first electrode between the barrier ribs. However, the present invention is not limited thereto, and an organic compound layer may be formed on the entire surface of the substrate 201.

A second electrode is formed on the organic compound layer in the display area.

A capping layer 229 made of an organic material such as a polymer is formed over the entire substrate 201 of the pixel portion on the substrate 201 on which the second electrode is formed.

The capping layer 229 may have a specific refractive index in the case of the top emission type and collect light to improve the emission of light. In the case of the back emission type, the capping layer 229 functions as a buffer for the second electrode of the organic light emitting diode .

The capping layer 229 may serve as one optical control layer. The capping layer 229 can increase the reflectivity at the interface between the capping layer 229 and the exterior by controlling the refractive index difference with the outside. This increase in reflectance allows the capping layer 229 to exhibit micro-cavity effects at specific wavelengths. At this time, the capping layer 229 may be formed with a different thickness for each sub-pixel.

On the capping layer 229, a transparent oxide layer 219 according to the present invention is formed, and a thin film encapsulating layer 240 composed of a multilayer is formed thereon.

In this case, when the oxide TFT is used as described above, an inorganic film such as a silicon nitride film or a silicon oxide film of the thin film encapsulation layer 240, that is, a gas generated at the time of high temperature / high humidity in the primary and secondary protective films 240a and 240c Ion affects the IGZO, which is the active layer of the oxide TFT, and causes an image quality defect. In the present invention, a transparent oxide layer 219 made of IZO or IGZO constituting the active layer of the oxide TFT is further formed under the thin film encapsulation layer 240, specifically below the primary and secondary protective films 240a and 240c . This is because gases or ions generated in the silicon nitride film, the silicon oxide film, or the like used for the primary and secondary protective films 240a and 240c penetrate and influence the IGZO, which is the active layer of the oxide TFT, so that IZO or IGZO Is added to the lower portion of the first and second protective films 240a and 240c to prevent gas or ions from being diffused toward the oxide TFT by absorbing it in advance. Such IZO or IGZO may be formed on the entire surface of the capping layer 229 through sputtering.

The transparent oxide layer 219 of the present invention may be formed to have substantially the same stepped portion according to the step of the capping layer 229 under the transparent oxide layer 219. That is, the organic compound layer and the second electrode on the first electrode, the capping layer 229, and the transparent oxide layer 219 may be formed to have a step according to a step formed by the barrier ribs.

Also, the first protective film 240a on the transparent oxide layer 219 is formed to have substantially the same stepped portion, and the organic film 240b thereon is formed on the entire surface of the substrate 201 as a planarizing film. That is, the organic film 240b may be formed such that the upper surface thereof is substantially planarized. Therefore, the secondary protective film 240c is not affected by the step difference caused by the lower film.

At this time, the capping layer 229 according to the second embodiment of the present invention may be formed so as to surround the active region of the pixel portion AAa excluding the outer frame portion AAb. A transparent oxide layer 219 may be formed thereon to cover the capping layer 229 in a hat shape. The first protective film 240a may be formed to cover the transparent oxide layer 219 in a hat shape.

That is, the second embodiment of the present invention includes a capping layer 229, a transparent oxide layer 219, and a transparent electrode layer 219 so as to cover not only the upper surface but also the side surface of the organic light emitting diode 202 in order to completely seal the active region of the pixel portion AAa. The tea protecting film 240a may be formed in a hat shape.

An organic layer 240b may be formed on the organic layer 240a, and a secondary protective layer 240c may be formed on the organic layer 240b to cover the organic layer 240b. However, the present invention is not limited to the above-described sealing structure.

The present invention can replace part or all of the inorganic film of the thin film encapsulation layer with a transparent oxide layer such as IZO or IGZO in order to fundamentally block penetration of gas or ions into the oxide TFT, The embodiment will be described in detail.

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

The organic light emitting display device according to the third embodiment of the present invention includes a panel assembly for displaying an image and a flexible circuit board connected to the panel assembly in substantially the same manner as in the first and second embodiments.

Referring to FIG. 10, the active region includes a pixel portion AAa in which a plurality of sub-pixels are arranged and displays an image, and a signal formed outside the pixel portion AAa to apply a signal applied from the outside to the pixel portion AAa And the thin film encapsulation layer 340 is formed on the panel part while covering a part of the pixel part AAa and the outer frame part AAb.

At this time, the panel portion which is not covered by the thin film sealing layer 340 and which is exposed forms a pad portion where the pad is formed.

A panel unit 310 is disposed on the upper surface of the substrate 301.

On the upper surface of the substrate 301, a thin film sealing layer 340 is formed to cover the panel portion. The thin film sealing layer 340 has a structure in which a plurality of inorganic films and organic films are alternately stacked by means of sealing the panel portion.

At this time, the portions that are not covered by the thin film sealing layer 340 and are exposed form the above-described pad region.

The capping layer 329 is formed on the upper surface of the substrate 301 on which the organic light emitting diode 302 is formed and the first protective layer 340a ' An organic film 340b and a secondary protective film 340c are sequentially formed to constitute a thin film encapsulation layer 340. [ However, the number of inorganic films and organic films constituting the thin film encapsulation layer 340 is not limited thereto.

At this time, a transparent oxide layer 319 according to the present invention is formed on the capping layer 329, and a thin-film encapsulating layer 340 composed of multiple layers is formed thereon.

In the case of the first protective film 340a ', the stacking coverage is poor due to the lower TFT step because the first insulating film 340a' is made of an inorganic insulating film such as IZO or IGZO. However, since the organic film 340b located on the top of the second protective film 340a ' 340c are not affected by the step difference caused by the lower film. Further, since the thickness of the organic film 340b made of the polymer is sufficiently thick, cracks due to foreign matter can be compensated.

A multilayer protective film 345 is disposed opposite to the front surface of the substrate 301 including the secondary protective film 340c to seal the panel 310 and the protective film 345 is disposed between the substrate 301 and the protective film 345 A pressure-sensitive adhesive 346 having transparency and adhesive properties is interposed.

On the protective film 345, a polarizing plate (not shown) may be attached to prevent reflection of light incident from the outside.

Although not shown, each sub-pixel includes an electronic device electrically connected to the organic light emitting diode and the organic light emitting diode, similar to the first and second embodiments of the present invention. The electronic device may include at least two or more TFTs, storage capacitors, and the like. The electronic device is electrically connected to the wirings and is driven by receiving an electrical signal from a driving element outside the panel portion.

In this manner, a first electrode made of transparent oxide is formed on a substrate 301 made of plastic or stainless steel, and an organic compound layer and a second electrode are sequentially stacked on the first electrode.

The TFT basically includes a switching transistor and a driving transistor.

As described above, the driving transistor includes an active layer, a gate electrode, and a source / drain electrode, and a first electrode of the organic light emitting diode may be connected to a drain electrode of the driving transistor. That is, the driving transistor includes a buffer layer formed on the substrate 301, an active layer formed on the buffer layer, a first insulating layer formed on the substrate 301 on which the active layer is formed, a gate electrode formed on the first insulating layer, And a source / drain electrode formed on the second insulating layer and electrically connected to a source / drain region of the active layer through the first contact hole.

The active layer may be formed of an oxide semiconductor.

A third insulating layer may be formed on the substrate 301 on which the driving transistor is formed, and the third insulating layer may be formed of an inorganic insulating material such as a silicon nitride film or a silicon oxide film.

The organic compound layer of the organic light emitting diode described above is formed on the first electrode between the barrier ribs. However, the present invention is not limited thereto, and an organic compound layer may be formed on the entire surface of the substrate 301.

A second electrode is formed on the organic compound layer in the display area.

A capping layer 329 made of an organic material such as a polymer is formed over the entire substrate 301 of the pixel portion on the substrate 301 on which the second electrode is formed.

The capping layer 329 has a specific refractive index in the case of the front emission type and can improve light emission by collecting light. In the case of the back emission type, the buffer layer 329 serves as a buffer for the second electrode of the organic light emitting diode .

The capping layer 329 may serve as one optical control layer. The capping layer 329 can increase the reflectivity at the interface between the capping layer 329 and the exterior by controlling the refractive index difference with the exterior. This increase in reflectance allows the capping layer 329 to exhibit micro-cavity effects at specific wavelengths. At this time, the capping layer 329 may be formed to have a different thickness for each sub-pixel.

On the capping layer 329, a multi-layer thin film encapsulation layer 340 is formed.

At this time, as described above, in the third embodiment of the present invention, part or all of the inorganic film of the thin film sealing layer 340 is replaced with a transparent oxide layer such as IZO or IGZO.

11A and 11B are cross-sectional views illustrating an example of an encapsulation structure of an organic light emitting display according to a third embodiment of the present invention.

11A shows an example in which a part of the inorganic film of the thin film sealing layer 340 is replaced with a transparent oxide layer such as IZO or IGZO. Referring to FIG. 11A, the first protective layer 340a 'of the thin film sealing layer 340 may be replaced with a transparent oxide layer such as IZO or IGZO.

11B shows an example in which the entire inorganic film of the thin film sealing layer 340 is replaced with a transparent oxide layer such as IZO or IGZO. Referring to FIG. 11B, the first and second protective layers 340a 'and 340c' of the thin film sealing layer 340 can be replaced with transparent oxide layers such as IZO and IGZO.

This is intended to fundamentally prevent gas or ions generated in the silicon nitride film or the silicon oxide film used in the thin film encapsulation layer 340 from penetrating and influencing the IGZO which is the active layer of the oxide TFT. Such IZO or IGZO can be formed on the entire surface of the substrate 301 through sputtering and has a moisture permeability similar to that of a conventional silicon nitride film or silicon oxide film so that the thickness of the thin film sealing layer 340 The first and second protective films 340a 'and 340c' may be used.

Referring again to FIG. 10, the organic compound layer, the second electrode, and the capping layer 329 on the first electrode may be formed to have a step according to a step formed by the barrier ribs.

Also, the first protective film 340a 'on the capping layer 329 is formed to have substantially the same stepped portion, and the organic film 340b thereon is formed on the entire surface of the substrate 301 as a planarizing film. That is, the organic film 340b may be formed such that the upper surface thereof is substantially planarized. Therefore, the secondary protective film 340c is not affected by the step difference caused by the lower film.

At this time, the capping layer 329 according to the third embodiment of the present invention may be formed on the entire surface of the organic light emitting diode 302, that is, on the active area of the pixel unit AAa as shown in the drawing, And may be formed to surround the active region of the pixel portion AAa. A primary protective film 340a 'as a transparent oxide layer may be formed to cover the capping layer 329 in a hat shape thereon.

An organic layer 340b is formed on the organic layer 340b, and a secondary protective layer 340c may be formed to cover the organic layer 340b in a hat shape. However, the present invention is not limited to the above-described sealing structure.

While a great many are described in the foregoing description, it should be construed as an example of preferred embodiments rather than limiting the scope of the invention. Therefore, the invention should not be construed as limited to the embodiments described, but should be determined by equivalents to the appended claims and the claims.

101, 201, 301: substrate 102, 202, 302: organic light emitting diode
129, 229, 329: capping layer 140, 240, 340: thin-
119, 219: transparent oxide layer

Claims

A TFT provided in a pixel portion of the substrate and including an active layer made of an oxide semiconductor;
An organic light emitting diode electrically connected to the TFT;
A capping layer provided on an upper surface of the substrate of the pixel portion having the organic light emitting diode;
A transparent oxide layer composed of the oxide semiconductor on the upper surface of the capping layer; And
And a thin-film encapsulating layer surrounding the transparent oxide layer, the thin encapsulation layer comprising at least an inorganic film provided on the transparent oxide layer and an organic film formed on the inorganic film.

The organic electroluminescent display device according to claim 1, wherein the transparent oxide layer and the active layer are made of IZO or IGZO.

The organic light emitting display according to claim 1, wherein the capping layer is provided on an entire surface of the substrate of the pixel portion, and the transparent oxide layer is provided on an upper surface of the capping layer.

The organic light emitting display device according to claim 1, wherein the transparent oxide layer absorbs gas or ions generated from the inorganic film on the upper portion thereof at high temperature / high humidity, and blocks diffusion of the gas or ion below the active layer.

The organic light emitting display according to any one of claims 1 to 4, wherein the transparent oxide layer has a cap shape to enclose the capping layer.

The organic light emitting display device according to any one of claims 1 to 4, wherein the inorganic film has a cap shape to enclose the transparent oxide layer.

5. The organic electroluminescent display device according to any one of claims 1 to 4, further comprising another transparent oxide layer composed of the oxide semiconductor between the inorganic film and the organic film.

A TFT provided in a pixel portion of the substrate and including an active layer made of an oxide semiconductor;
An organic light emitting diode electrically connected to the TFT;
A capping layer provided on an upper surface of the substrate of the pixel portion having the organic light emitting diode; And
And a thin film encapsulating layer surrounding the capping layer, the thin encapsulation layer being formed by alternately laminating the inorganic film and the organic film at least once,
Wherein at least one of the inorganic films is replaced with a transparent oxide layer composed of the oxide semiconductor.

The organic electroluminescent display device according to claim 8, wherein the transparent oxide layer and the active layer are made of IZO or IGZO.