KR20150063844A - Fabricating Method Of Organic Light Emitting Diode Display - Google Patents

Abstract

As an organic light emitting diode with face sealing technology applied, the present invention provides an organic light emitting diode display device which includes a substrate on which an effective display region and a pad region are defined, a driving and switching thin film transistor which is formed in the effective display region, a pad part which is formed in the pad region, the organic light emitting diode which is formed in the effective display region and is connected to the driving thin film transistor, a first protection layer which is made of an inorganic material and covers the organic light emitting diode and the pad part, a partition which is formed on the upper side of the first protection layer to surround the effective display region, a second protection layer which is made of an organic material and is formed on the inner side of the partition, and a third protection layer which is made of the inorganic material and covers the second protection layer and the partition. Particularly, the quality of a display is improved by uniformly forming the thickness of a display device by forming the partition surrounding a display region which prevents moisture and oxygen from permeating.

Description

Technical Field [0001] The present invention relates to an organic light emitting diode (OLED) display device,

The present invention relates to a method of manufacturing an organic light emitting diode display.

2. Description of the Related Art In recent years, development of various flat panel displays (FPD) has been accelerated. In particular, an organic light emitting diode (OLED) display device has advantages of high response speed, high luminous efficiency, high luminance and wide viewing angle by using a self-luminous element which emits light by itself.

The organic light emitting diode display device has an organic light emitting diode (OLED), or an organic light emitting diode, for self light emission. The organic light emitting diode has an organic compound layer formed between the anode and the cathode. The organic compound layer includes a hole injection layer, a hole transport layer, an emission layer, an electron transport layer, and an electron injection layer. When driving voltage is applied to the anode and the cathode, electrons passing through the hole transport layer (HTL) and electrons passing through the electron transport layer (ETL) are combined with each other in the light emitting layer (EML) to form excitons, So that visible light is generated.

Such organic light emitting diodes are characterized by being very vulnerable to moisture and oxygen in the air. Accordingly, in the manufacturing process of the organic light emitting diode display device, an encapsulation process is required to seal the organic light emitting diode to prevent moisture and oxygen from penetrating. The sealing process is indispensable for securing the reliability of the organic light emitting diode display device by increasing the lifetime of the organic material.

This sealing process is known as edge sealing technique and face sealing technique including ultra violet sealing method and frit sealing method. The UV sealing method is the oldest method using a glass sealing substrate and a moisture absorber.

The frit sealing method, which is mainly used in small products, is a method of sealing a substrate and an encapsulating substrate by using a low-temperature frit. However, it has a limitation in application to a large substrate because it is weak against an external impact.

Face sealing technology has been developed to solve the external impact problem when applying large size products. The face sealing technique is a method of filling the entire void space between the encapsulation substrate and the organic light emitting diode (OLED) substrate using organic materials. The method of filling the organic material can be variously formed in general by screen printing, slit coating, one drop filing (ODF), dispenser, Due to its nature, its ability to block moisture and oxygen can cause pixel shrinkage compared to inorganic materials. In general, the face sealing technique protects the organic light emitting diode (OLED) from external shock, moisture, and oxygen by passivating the organic light emitting diode device (OLED) with an inorganic material prior to filling the organic material.

However, in the process of filling the organic material, convex shaped protrusions are formed at both ends of the display device (for example, at the boundary between the display area and the non-display area) due to the cohesive force between the organic material and the mask. And the light generated from the organic light emitting diode OLED is distorted due to the thickness difference, thereby causing a problem that the display quality is deteriorated.

Accordingly, it is an object of the present invention to provide an organic light emitting diode display device having a uniform thickness in applying a face sealing technique.

In order to solve the above-mentioned problems, the present invention provides a display device comprising: a substrate on which an effective display area and a pad area are defined; A driving and switching thin film transistor formed in the effective display region; A pad portion formed in the pad region; An organic light emitting diode formed in the effective display region and connected to the driving thin film transistor; A first protective layer of an inorganic material covering the organic light emitting diode and the pad portion; A partition wall formed on the first protective layer to surround the effective display area; A second protective layer of organic material formed inside the barrier rib; And a third passivation layer of an inorganic material covering the second passivation layer and the barrier ribs.

The barrier rib is formed to have a thickness of 0.5 to 30 탆.

The organic material is characterized by being an epoxy resin or a material having a relatively high transmittance to light and capable of thermal curing, UV curing and natural curing.

According to another aspect of the present invention, there is provided a method of manufacturing a semiconductor device, comprising: preparing a substrate on which an effective display region and a pad region are defined; Forming driving and switching thin film transistors in the effective display area; Forming a pad portion in the pad region; Forming an organic light emitting diode connected to the driving thin film transistor in the effective display region; Forming a first protective layer of an inorganic material covering the organic light emitting diode and the pad portion; Forming a barrier rib from an organic material formed on the first passivation layer so as to surround the effective display area; Forming a second protective layer of organic material inside the barrier; And forming a third protective layer of an inorganic material covering the second substrate and the barrier ribs.

The first and third protective layers may be formed using a PVD (Physical Vapor Deposition) process such as sputtering or a PECVD (Plasma Enhanced Chemical Vapor Deposition) process.

Wherein the barrier ribs are formed by using a coating apparatus so as to surround the liquid display type organic material so as to surround the effective display area, and are cured by any one of thermal curing, UV curing and natural curing.

And the second protective layer is formed by ejecting or dropping the organic material of liquid type onto the substrate of the effective display area surrounded by the partition using the coating apparatus.

The coating apparatus may be a device using any one of a roll printing method, a screen printing method, an ODF (One Drop Filling) method, a dispenser method, a spin method, and a slit method. .

As described above, according to the present invention, barrier ribs are formed to surround a display area in a sealing process for preventing moisture and oxygen from penetrating. This makes it possible to uniformly form the thickness of a display device, .

FIG. 1A is a cross-sectional view of a portion of a display region of an organic light emitting diode display according to an embodiment of the present invention, and FIGS. 1B and 1C are cross-sectional views of a drive thin film transistor in an organic light emitting diode.
2A to 2F are views sequentially illustrating an example of forming an organic light emitting diode display device according to an embodiment of the present invention.

Hereinafter, an organic light emitting diode display device according to the present invention will be described with reference to the accompanying drawings.

1A is a cross-sectional view of a portion of a display region of an organic light emitting diode display according to an embodiment of the present invention. In this case, for convenience of description, a region where a switching thin film transistor is to be formed in each pixel region is defined as a switching region, and a region where a driving thin film transistor is to be formed is defined as a driving region, and a driving thin film transistor is formed for each pixel, Only one pixel region is shown.

As shown in FIG. 1A, on a substrate 101, intrinsic polysilicon is formed in each pixel region P, and a central portion thereof includes a first region 113a in which a channel is formed and a first region 113b in which both sides of the first region 113a are formed. A semiconductor layer 113 composed of a second region 113b and a third region 113c doped with impurities of the furnace is formed.

A buffer layer (not shown) made of an inorganic insulating material such as silicon oxide (SiO ₂ ) or silicon nitride (SiNx) may be provided on the entire surface between the semiconductor layer 113 and the first substrate 101.

A gate insulating layer 110 is formed on the entire surface of the substrate 101 so as to cover the semiconductor layer 113. A gate insulating layer 110 is formed on the gate insulating layer 110 to correspond to the first region 113a of the semiconductor layer 113, (Not shown). Further, a gate wiring (not shown) extending in one direction is formed on the gate insulating film 110. At this time, the gate electrode 123 is connected to the gate wiring (not shown).

An interlayer insulating film 120 is formed on the upper surface of the gate electrode 123 and the gate wiring (not shown). At this time, the interlayer insulating layer 120 and the gate insulating layer 110 thereunder are formed with semiconductor layer contact holes 135 exposing the second and third regions 113b and 113c located on both sides of the first region 113a .

Over the interlayer insulating film 120 including the semiconductor layer contact hole 135, a data line 137 is formed which crosses the gate line (not shown) and defines each pixel region P.

The source and drain electrodes 133a and 133b connected to the second and third regions 113b and 113c, which are separated from each other and are exposed through the semiconductor layer contact holes 135, are formed in the respective driving regions and switching regions above the interlayer insulating layer 120, And 133b are formed.

The semiconductor layer 113 includes the source and drain electrodes 133a and 133b and the second and third regions 113b and 113c connected to the electrodes 133a and 133b. The gate insulating film 110 and the gate electrode 123 formed on the substrate 110 constitute a driving and switching thin film transistor DTr (not shown).

A switching thin film transistor (not shown) is electrically connected to the driving thin film transistor DTr and a gate wiring (not shown) and a data wiring 137. The data wiring 137 is connected to a source electrode (Not shown), and the driving thin film transistor DTr is connected to the organic light emitting diode E.

Although the driving thin film transistor DTr and the switching thin film transistor (not shown) have a polysilicon semiconductor layer 113 and are of a top gate type, the driving and switching thin film transistors (DTr, not shown) is formed on the semiconductor layer of amorphous silicon (225 in FIG. 1B) or the semiconductor layer of the amorphous silicon as shown in FIGS. 1B and 1C (sectional view of another example of the drive thin film transistor in the organic light emitting diode element of the present invention) Or a bottom gate type having a semiconductor layer (321 in FIG. 1C) made of an oxide semiconductor material.

1B, the gate electrode 213, the gate insulating film 210, and the active layer 223 of pure amorphous silicon are spaced apart from each other and the impurity A semiconductor layer 225 composed of an amorphous silicon ohmic contact layer 224 and source and drain electrodes 233a and 233b spaced apart from each other or having a stacked structure of gate electrodes 313 And source and drain electrodes 325a and 325b which are separated from each other on the gate insulating film 310, the oxide semiconductor layer 321, the etch stopper 323, and the etch stopper 323 and are in contact with the oxide semiconductor layer 321, , And 325b.

In the case of the substrate (301 in FIG. 1B, 301 in FIG. 1C) on which the bottom gate type driving and switching thin film transistor DTr (not shown) is formed, the gate wiring (not shown) (Not shown) of a switching thin film transistor (not shown) is formed on the same layer on which the source electrode (not shown) of the switching thin film transistor 313 is formed, and a data line (Not shown) is formed on the same layer.

1A, power wiring (not shown) is formed on the same layer on which the gate wiring (not shown) is formed or the same layer on which the data wiring 137 is formed, although not shown in the drawing. (Not shown) is connected to one electrode of the driving thin film transistor DTr.

A first passivation layer 130 is formed on the entire surface of the substrate 101 above the driving and switching thin film transistor DTr (not shown). At this time, a drain contact hole 142 exposing the drain electrode 133b of the driving thin film transistor DTr is formed in the first passivation layer 130.

The drain electrode 133b of the driving thin film transistor DTr and the drain contact hole 142 are connected to the upper portion of the first passivation layer 130 having the drain contact hole 142, A first electrode 143a is formed.

The first electrode 143a may be made of a transparent conductive material having a relatively large work function value such as indium-tin-oxide (ITO) or indium-zinc-oxide (IZO) to serve as an anode electrode.

The first electrode 143a may be formed in a double layer structure. An upper layer (not shown) of the first electrode 143a serves as an anode electrode, and a lower layer (not shown) do. The lower layer (not shown) may be made of a metal material having excellent reflection efficiency, for example, aluminum (Al) or silver (Ag), and light emitted from the organic light emitting layer 143b formed on the first electrode 143a, So as to improve the luminous efficiency.

Next, the first electrode 143a is overlapped with the edge of the first electrode 143a in such a manner as to surround each pixel region P at the boundary of each pixel region P, The bank 140 is exposed.

The bank 140 may be made of a common transparent organic insulating material such as polyimide, photo acryl, or benzocyclobutene (BCB), and may be made of, for example, It is possible.

An organic light emitting layer 143b is formed on the first electrode 143a in each pixel region surrounded by the bank 140 so as to emit red, green, or blue light . At this time, the organic light emitting layer 143b may include red, green, blue and white light emitting materials including red, green, and blue light emitting materials.

A second electrode 143c serving as a cathode electrode is formed on the entire surface of the display region above the organic light emitting layer 143b. At this time, the first and second electrodes 143a and 143c and the organic light emitting layer 143b formed therebetween constitute the organic light emitting diode 143.

The second electrode 143c may be formed of a metal material having a relatively low work function value such as aluminum (Al), aluminum alloy (AlNd), silver (Ag), magnesium (Mg) Au, aluminum magnesium alloy (AlMg), or two or more materials.

Meanwhile, when the organic light emitting diode 143 is driven by the top emission type, the second electrode 158 may be formed to have a thin thickness, in which light is transmitted smoothly and light transmission is maintained. In this case, if the thickness of the second electrode 143c is formed to have a thin thickness for maintaining the light transmittance, the sheet resistance will increase with a thin thickness due to the characteristics of the metal material. In order to reduce the sheet resistance, It is also possible to form an auxiliary wiring to be connected to the wiring 143c.

Hereinafter, the formation process of the organic light emitting diode display device of the present invention having the above-described structure will be described in detail with reference to the drawings.

2A to 2F are views sequentially showing an example of forming an organic light emitting diode display device according to an embodiment of the present invention.

The organic light emitting diodes 143 are formed in the effective display area AA of the substrate 101 as shown in FIG. The organic light emitting diode 143 includes a first electrode (143a in FIG. 1A), a second electrode (143c in FIG. 1A), and an organic light emitting layer (143b in FIG. 1A) formed therebetween.

The first electrode (143a in FIG. 1A) is deposited in the effective display area AA by a sputtering process, and is then patterned pixel by pixel through a photolithography process and an etching process.

On the other hand, a driving and switching thin film transistor (DTr) (not shown) is formed under the organic light emitting diode 143 as shown in FIG. 1A.

The organic light emitting layer 143b of FIG. 1A includes a hole injection layer, a hole transporting layer, an emitting material layer, and an electron transporting layer sequentially from the top of the first electrode 143a an electron transporting layer, and an electron injection layer.

The organic light emitting layer 143b may include a hole transporting layer, an emitting material layer, an electron transporting layer and an electron injection layer, a four-layer structure, a hole transporting layer ), A light emitting layer (an emitting material layer), and an electron transporting layer (an electron transporting layer).

A bank (140 in FIG. 1A) for partitioning neighboring pixels may be formed between the first electrode (143a in FIG. 1A) and the organic emission layer (143B in FIG. 1A).

The second electrode (143c in FIG. 1A) is deposited by thermal evaporation on the organic light emitting layer (143c in FIG. 1A) of the effective display area AA.

A pad portion 190 to be in contact with a driver IC (Integrated Circuit) or an FPC (Flexible Printed Circuit) is formed on the pad region PA of the substrate 101. The pad portion 190 may be formed in the above-described manufacturing process of the driving and switching transistor (DTr in FIG. 1A, not shown).

Subsequently, a PVD (Physical Vapor Deposition) process such as sputtering or a PECVD (Plasma Enhanced Chemical Vapor Deposition) process such as sputtering is performed on the substrate 101 on which the organic light emitting diode 143 and the pad unit 190 are formed. The first passivation layer 150 is formed. At this time, the first passivation layer 150 is formed only on the effective display area AA formed with the organic light emitting diode elements 143 using the mask 200.

Next, as shown in FIG. 2B, an organic material is applied to the outermost display region AA using the coating apparatus 195 corresponding to the substrate 101 on which the first protective layer 150 is formed, . At this time, the organic structure 160 is formed to surround the display area AA. Here, the organic material is preferably an epoxy resin or a material having a high transmittance and capable of curing means described later.

In detail, the coating apparatus 195 will be described in detail. For example, the coating apparatus 195 includes a roll offset printing system using a printing blanket, a printing table and a cleaner, a photosensitive printing system using a very fine mesh screen Screen printing method in which organic matters are printed using a squeegee after the organic matters pass through the necessary parts to prevent unnecessary parts and one drop filling method in which organic substances are dropped and patterned, A coating apparatus 195 capable of patterning an organic material such as an organic solvent (ODF), a dispenser, a spin, a slit, and the like.

 Next, as shown in FIG. 2C, the substrate 101 on which the organic structure (160 in FIG. 2B) is formed is cured by means of curing means such as thermal curing, UV curing, natural curing, To complete the transparent and rigid barrier rib 162 in the form of surrounding the display area AA. At this time, it is preferable to control the curing time so that the partition wall 162 is formed to have a thickness of 0.5 to 30 탆 through the curing means.

Next, as shown in Fig. 2D, by spraying or dropping organic material onto the substrate 101 in the display area AA surrounded by the partition wall 162 using the coating device 195, the second protective layer 163 ). The second protective layer 162 may be formed of the same material as the barrier ribs 162.

Here, by forming the second protective layer 162 using the coating device 195, conventionally, a convex hill is formed at the outermost portion of the display area AA due to the cohesive force between the mask and the organic material, thereby solving the problem .

2E, the substrate 101 on which the second protective layer 163 is formed is moved to the second protective layer 163 by curing means, for example, curing means such as the partition 162 described above, .

2F, a PVD (Physical Vapor Deposition) process such as sputtering or a PECVD (Plasma Enhanced Chemical Vapor Deposition) process is performed on the substrate 101 on which the second protective layer 163 is formed The organic light emitting diode display device is completed by forming the third passivation layer 170 made of an inorganic material. At this time, the third passivation layer 170 is formed only in the effective display area AA formed with the organic light emitting diode elements 143 using the mask 200, like the first passivation layer 150.

The present invention is not limited to the above-described embodiments, and various modifications may be made without departing from the spirit of the present invention.

AA: effective display area PA: pad area
101: substrate 143: organic light emitting diode
150: first protective layer 162: barrier rib
163: second protection layer 170: third protection layer
190: Pad part 195: Coating device
200: mask

Claims (8)

A substrate on which an effective display area and a pad area are defined;
A driving and switching thin film transistor formed in the effective display region;
A pad portion formed in the pad region;
An organic light emitting diode formed in the effective display region and connected to the driving thin film transistor;
A first protective layer of an inorganic material covering the organic light emitting diode and the pad portion;
A partition wall formed on the first protective layer to surround the effective display area;
A second protective layer of organic material formed inside the barrier rib;
And a third passivation layer of an inorganic material covering the second passivation layer and the barrier ribs.
The method according to claim 1,
Wherein the barrier ribs are formed to have a thickness of 0.5 to 30 占 퐉.
The method according to claim 1,
Wherein the organic material is an epoxy resin or a material having a relatively high transmittance to light and capable of thermosetting, UV curing and natural curing.
Preparing a substrate on which an effective display area and a pad area are defined;
Forming driving and switching thin film transistors in the effective display area;
Forming a pad portion in the pad region;
Forming an organic light emitting diode connected to the driving thin film transistor in the effective display region;
Forming a first protective layer of an inorganic material covering the organic light emitting diode and the pad portion;
Forming a barrier rib from an organic material formed on the first passivation layer so as to surround the effective display area;
Forming a second protective layer of organic material inside the barrier;
And forming a third protective layer of an inorganic material covering the second substrate and the barrier ribs.
5. The method of claim 4,
Wherein the first passivation layer and the third passivation layer are formed using a PVD (Physical Vapor Deposition) process such as a sputtering process or a PECVD (Plasma Enhanced Chemical Vapor Deposition) process. .
5. The method of claim 4,
Wherein the barrier ribs are formed by using a coating apparatus so as to surround the liquid display type organic material so as to surround the effective display area and then cured by any one of thermal curing, UV curing and natural curing. Way.
5. The method of claim 4,
Wherein the second protective layer is formed by ejecting or dropping a liquid type organic material onto the substrate of the effective display area surrounded by the partition using the coating apparatus. Way.
8. The method according to claim 6 or 7,
The coating apparatus may be a device using any one of a roll printing method, a screen printing method, an ODF (One Drop Filling) method, a dispenser method, a spin method, and a slit method. Wherein the organic light emitting diode display device comprises a plurality of organic light emitting diodes.

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