KR20170041487A - Luminescence dispaly panel - Google Patents

Abstract

The present invention relates to a light emitting display panel which prevents an organic layer from peeling off during implementation of a fordable display by applying a spherical spacer and not forming the organic layer on a contact surface between the spherical spacer and a bank layer, and at the same time, minimizes foreign substances generated on a contact surface between an FMM and the spacer. The light emitting display panel of the present invention comprises an organic layer including a light emitting layer between a first electrode and a second electrode located on a substrate, and further comprises a bank insulating film including an organic hole for defining a light emitting area on the first electrode. The light emitting display panel also comprises a spherical spacer made of a hydrophobic polymer material or a conductive nanoparticle coated with the hydrophobic polymer material on an upper portion of the bank insulating film.

Description

[0001] LUMINESCENCE DISPALY PANEL [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light emitting display panel, and more particularly, to a light emitting display panel having a spherical spacer to prevent peeling of an organic layer and to prevent damage to an organic layer during an organic layer deposition process.

The image display device that realizes various information on the screen is a core technology of the information communication age and it is becoming thinner, lighter, more portable and higher performance. An organic light emitting display (OLED) for displaying an image by controlling the amount of light emitted from the organic light emitting layer by using a flat panel display capable of reducing weight and volume, which is a disadvantage of a cathode ray tube (CRT) OLED is a self-luminous device using a thin light emitting layer between electrodes and has the advantage of being thin like a paper.

In the active matrix OLED (AMOLED), pixels composed of three color (R, G, B) sub-pixels are arranged in a matrix form to display an image. Each sub-pixel includes an organic electroluminescent (OEL) cell and a cell driver for independently driving the OEL cell.

The OEL cell includes a first electrode connected to a cell driving unit, a bank insulating film formed with an organic hole for exposing the first electrode, an organic layer including a light emitting layer located above the first electrode, and a second electrode formed on the organic layer do. At this time, spacers are provided on the upper portion of the bank insulating film.

The cell driver includes at least two thin film transistors and a storage capacitor connected between a gate line for supplying a scan signal, a data line for supplying a video data signal, and a common power supply line for supplying a common power supply signal, do.

In recent years, various types of foldable display using OLED have been proposed. However, in the case of the conventional OLED, the organic layer including the light emitting layer has a weak adhesive force, resulting in peeling of the organic layer near the folding region.

In order to solve the above problems, the applicant has filed an application for an OLED device having an inverted spacer in which the shape of the spacer is inverted to an inverted trapezoidal shape.

However, an OLED device having an inverse spacer increases the contact area between an FMM (fine metal mask) used for forming an OLED and an inverse spacer due to an increase in an upper contact area, and a contact area between the FMM and an inverse spacer Foreign objects caused defective OLED devices.

SUMMARY OF THE INVENTION The present invention has been conceived to solve the problems described above, and it is an object of the present invention to provide a spherical spacer and a bank layer, And an OLED device in which foreign matter generated on the contact surface with the spacer is minimized.

According to an aspect of the present invention, there is provided an organic light emitting diode display panel including a first electrode and a second electrode, the organic layer including a light emitting layer between the first electrode and the second electrode, And a spherical spacer made of a hydrophobic polymer material or a conductive nanoparticle coated with a hydrophobic polymer material on the bank insulating film.

The organic light emitting display panel according to the present invention may have both the spherical spacer and the positive spacer on the bank insulating film, wherein the height of the positive spacer is higher than the height of the spherical spacer.

In the organic light emitting display panel according to the present invention, the FMM contacts the top of the spherical spacer at the time of forming the organic layer, thereby improving the peeling of the organic layer generated in the foldable display and at the same time the contact between the FMM and the spherical spacer Since the area is small, it is possible to improve the foreign matter phenomenon caused by the contact between the FMM and the spacer. In addition, in the case where only the spherical spacer is formed on the organic light emitting display panel according to the present invention, the photolithography process and the etching process for forming the positive spacers can be omitted.

On the other hand, the organic light emitting panel in which the positive spacer and the spherical spacer are both formed can minimize the contact area between the FMM and the spacer because the positive spacer and the FMM are in contact with each other and the spherical spacer and the FMM are not in contact with each other. The peeling phenomenon of the organic layer occurring in the display can be improved.

1 is an equivalent circuit diagram of a pixel of a light emitting display panel according to the present invention.
2 is a cross-sectional view illustrating a structure of a light emitting display panel according to the present invention.
3 is a cross-sectional view illustrating a light emitting display panel including both a positive spacer and a spherical spacer.
4A to 4K are views for explaining a method of forming the light emitting display panel according to the present invention.

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

1 is an equivalent circuit diagram of a pixel of a light emitting display panel according to the present invention.

One pixel of the light emitting display panel shown in FIG. 1 includes a switch thin film transistor T1 connected to a gate line GL and a data line DL, a switch thin film transistor T1 and a power line PL, an OEL cell, A storage capacitor C connected between the power source line PL and the drain electrode of the switch thin film transistor T1 and an OEL cell connected to the drive thin film transistor T2 .

The gate electrode of the switch thin film transistor T1 is connected to the gate line GL, the source electrode thereof is connected to the data line DL and the drain electrode thereof is connected to the gate electrode of the driving TFT T2 and the storage capacitor C . The source electrode of the driving thin film transistor T2 is connected to the power supply line PL and the drain electrode is connected to one of the electrodes of the OEL cell. The storage capacitor C is connected between the power supply line PL and the gate electrode of the driving thin film transistor T2.

The switch thin film transistor T1 is turned on when a scan pulse is supplied to the gate line GL to supply the data signal supplied to the data line DL to the gate electrode of the storage capacitor C and the drive thin film transistor T2 do. The driving thin film transistor T2 controls the amount of light emitted from the OEL cell by controlling the current I supplied from the power source line PL to the OEL cell in response to the data signal supplied to the gate electrode. Even if the switch thin film transistor T1 is turned off, the driving thin film transistor T2 supplies the constant current I until the data signal of the next frame is supplied by the voltage charged in the storage capacitor C, Allowing the cell to maintain luminescence.

The driving thin film transistor T2 is formed on the substrate 100 and the buffer layer 101 as shown in Fig. 2 and has a semiconductor layer 104 including a source region 109a and a drain region 109b on both sides, A gate insulating film 106 covering the semiconductor layer 104, a gate electrode 102 located above the gate insulating film 106 corresponding to the semiconductor layer 104, and a gate electrode 102 including the gate electrode 102. [ A first passivation layer 112 covering the source and drain regions 100 and including contact holes 113 exposing source / drain regions 109a and 109b located on both sides of the semiconductor layer 104, And a source electrode 110 and a drain electrode 108 which are connected to the source / drain regions 109a and 109b through the source / drain regions 113 and 113, respectively.

The OEL cell includes a first protective film 112 covering the driving thin film transistor and a first insulating film 116 on the second protective film 114 and a bank insulating film 124 having an organic hole for exposing the first electrode 116, An organic layer 118 including a spherical spacer 126 located on the bank insulating film 124 and a light emitting layer formed on the first electrode 116 exposed through the organic hole and a second electrode 118 formed on the organic layer 118. [ (120).

The spherical spacers 126 may be formed of a hydrophobic thermosetting resin or may be formed of conductive nanoparticles coated with a hydrophobic polymer compound.

The first protective film 112 includes a contact hole 122 exposing the drain electrode 108 and the first electrode 116 is connected to the drain electrode 108 of the thin film transistor through the contact hole 122 do.

At this time, the substrate 100 is a flexible glass or polymer substrate, and the light emitting display panel according to the present invention can be manufactured as a flexible display or a foldable display.

The organic layer 118 includes an electron injection layer (EIL), an electron transport layer (ETL), a light emitting layer 206, a hole transport layer (HTL), a hole injection layer (HIL) ). The excitons generated by the recombination of the electrons from the cathode and the holes from the anode emit light of a specific wavelength while returning to the ground state.

In this case, when the first electrode 116 is a cathode, the second electrode 120 is an anode, and when the first electrode 116 is an anode, the second electrode 120 becomes a cathode.

On the other hand, the organic layer 118 and the second electrode 120 are also located on top of the spherical spacer.

The organic layer 118 and the second electrode 120 formed on the bank insulating film 124 are not formed at a position where the spherical spacer 126 and the bank insulating film 124 are in contact with each other, The organic layer 118 is not formed. The organic layer 118 formed on the spherical spacer 126 and the organic layer 118 formed on the organic hole and the bank insulating film 124 are separated from each other at the point where the spherical spacer 126 and the bank insulating film 124 are in contact with each other.

When the spherical spacer 126 is formed on the bank insulating film 124 as described above, the organic layer 118 is not deposited on the side where the spherical spacer 126 contacts the bank insulating film 124 and the side surface of the spherical spacer 126 The continuity of the organic layer 118 is partially cut off. The barrier layer 130 is formed in a region where the continuity of the organic layer 118 is broken and the barrier layer 130 is formed at a position where the spherical spacer 126 and the bank insulating film 124 are in contact with each other, And has an effect of securing the organic layer 118 located under the barrier layer 130 because of its excellent adhesion to the side surface.

Accordingly, the light-emitting display panel according to the present invention can improve the adhesion of the organic layer 118, and can prevent peeling of the organic layer 118 in the folding area, particularly when implementing a foldable panel.

Since the light-emitting display panel according to the present invention uses the spherical spacer 126, the contact area between the FMM (Fine Metal Mask) used for forming the organic layer 118 and the spacer is smaller than that small. Accordingly, when the spherical spacer 126 is used as in the present invention, the peeling phenomenon of the organic layer generated in the foldable display can be improved, and foreign matter generated by the contact between the inverse spacer and the FMM can be minimized.

3 is a cross-sectional view illustrating a light emitting display panel including both a positive spacer and a spherical spacer.

As shown in FIG. 3, the light emitting display panel according to the present invention may be formed with both the spacer 128 and the spherical spacer 126 which are conventionally used in different regions above the bank insulating film 124. The conventional spacer is formed in a shape having a narrower width of the upper region than the lower region, and is referred to as a 'positive spacer 128' for convenience.

At this time, the height of the positive spacer 128 is higher than the height of the spherical spacer 126. Therefore, the FMM used when forming the organic layer 118 is contacted with the positive spacer 128. [

In other words, the light-emitting display panel according to the present invention maintains the gap between the light-emitting display panel and the FMM using the positive spacer 128, and the organic layer 118, which occurs when the spherical spacer 126 is used to implement the foldable display, Thereby preventing the peeling phenomenon.

4A to 4K are views for explaining a method of forming the light emitting display panel according to the present invention.

4A, a buffer layer 101 is formed on a substrate 100, and a semiconductor layer 104 is formed thereon. At this time, the buffer layer 101 and the semiconductor layer 104 are formed using a deposition method such as PECVD (Plasma Vapor Deposition). Then, the semiconductor layer 104 is patterned through a photolithography process and an etching process.

Referring to FIG. 4B, an inorganic insulating material is deposited on a substrate 100 including a semiconductor layer 104 through a deposition method such as PECVD, thereby forming a gate insulating film 106. A metal layer is deposited thereon by a method such as sputtering and is patterned by a photolithography and etching process to form the gate electrode 102.

The source and drain regions 109a and 109b are formed by implanting impurities into the both sides of the semiconductor layer 104 through ion implantation or the like using the gate electrode 102 as a mask.

Referring to FIG. 4C, a first protective layer 112 is formed on a substrate 100 including a gate electrode 102 and a semiconductor layer 104 through a deposition method such as PECVD. A contact hole 113 is formed in the first protective film 112 to expose the source / drain regions 109a and 109b through a photolithography process and an etching process.

Referring to FIG. 4D, a metal layer for forming the source electrode 110 and the drain electrode 108 is deposited by a method such as sputtering. As the source / drain metal layer, molybdenum (Mo), molybdenum tungsten (MoW), copper (Cu), or the like is used. The source / drain metal layer is patterned by a photolithography process and an etching process, thereby forming a source / drain electrode pattern including the source electrode 110 and the drain electrode 108.

 4E, a second passivation layer 114 including a contact hole 122 is deposited on the first passivation layer 112 including the source electrode 110 and the drain electrode 108. Referring to FIG. At this time, the second protective layer 114 may be formed of an organic insulating material such as acryl or the like through a method such as spin coating or spinless coating. A contact hole 122 exposing the drain electrode 108 is formed in the second protective film 114 by a photolithography process and an etching process.

Referring to FIG. 4F, a first electrode 116 is formed on the second protective layer 114.

Specifically, the first electrode 116 may be formed on the second protective layer 114 by using an opaque conductive material such as aluminum (Al) or a transparent conductive material such as ITO by a deposition method such as sputtering. The first electrode 116 is connected to the drain electrode 108 of the thin film transistor through the contact hole 122.

Referring to FIG. 4G, a bank insulating layer 124 including an organic hole 140 is formed on a substrate 101 on which a first electrode 122 is formed on a first electrode 116.

A photosensitive organic insulating material is coated on the bank insulating film 124 and the organic hole 140 through a coating method such as spin-spin or spin coating in the same manner as the bank insulating film 124 to form an organic insulating layer for forming spacers . The positive insulating spacer 128 is formed by patterning the organic insulating layer by a photolithography process and a patterning process.

In the case of forming only the spherical spacers 126, the process of forming the positive spacers 128 may be omitted. That is, in the case of forming only the spherical spacers 126, the photolithography process and the etching process for forming the positive spacers 128 can be omitted, thereby reducing the manufacturing process.

The process of forming the spherical spacers 126 will be described in detail with reference to Figs. 4H and 4I.

The spherical spacers 126 are formed by injecting a hydrophobic thermosetting resin capable of forming the spherical spacers 126 in a state in which only the bank insulating film 124 is exposed by using the mask 150 as shown in FIG. do.

At this time, the bank insulating film 124 is made of a hydrophobic material, and the metal forming the first electrode 122 is made hydrophilic. thereafter. The spherical spacers 126 are not formed on the first electrode 122 which is hydrophilic, but may be formed only on the upper portion of the bank insulating film 124.

On the other hand, the spherical spacers 126 can be formed by using an electric field as shown in FIG. 4I. To this end, spherical spacers 126 are formed using conductive nanoparticles 132 coated with a hydrophobic polymeric compound 132.

At this time, the mask 150 is a metal mask, and an electric field is applied to the mask 150 so that the mask 150 is charged, and the conductive nanoparticles 132 coated with the hydrophobic polymer compound 134 are applied to the mask 150 By spraying, the nanoparticles 132 are allowed to adhere to the mask 150.

The nanoparticles 132 are positioned on the bank insulating layer 124 and the spherical spacers 126 are formed on the upper surface of the bank insulating layer 124. [ .

Since the spherical spacer 126 is coated with the hydrophobic polymer compound 134, the spherical spacer 126 is not formed on the hydrophilic first electrode 122 but only on the upper portion of the bank insulating film 124.

After forming the spherical spacers 126 as described above, the organic layer 126 and the second electrode 128 are formed on the substrate 101 on which the bank insulating layer 124 including the organic hole 140 is formed, Respectively.

  An organic layer 118 including an electron injection layer (EIL), an electron transport layer (ETL), a light emitting layer, a hole transport layer (HTL), and a hole injection layer (HIL) is formed on the first electrode 116 by a thermal deposition method, Or a combination thereof. FMM is used for forming the organic layer 118, and the FMM is fixed and supported by the positive spacer 128 or the spherical spacer 126.

At this time, since the FMM is in contact with the positive spacer 128 or only partially in the upper part of the upper part of the spherical spacer 126, the generation of foreign matter is remarkably reduced as compared with the case where the reverse spacer is used.

Thereafter, the second electrode 120 is formed on the substrate 100 on which the organic layer 118 is formed.

The second electrode 120 may have a multi-layer structure using a transparent conductive material or a metal material, or may have a multi-layer structure using a transparent conductive material and a metallic material.

Referring to FIG. 4K, a barrier layer 130 is formed on the second electrode 120. The barrier layer 130 has a structure in which at least one inorganic film 127 and the organic film 129 are stacked in an alternating manner and may be formed by an ALD (Atomic Layer Deposition) method or the like.

An upper substrate (not shown) may be further formed on the barrier layer 130, but the upper substrate may not be provided.

The organic light emitting display panel according to the present invention can be manufactured by forming the spherical spacers 126 or forming the positive spacers 128 and the spherical spacers 126. When the organic layer 118 is formed, Contact with the upper portion of the spacer 126 improves the peeling phenomenon of the organic layer 118 generated in the foldable display and at the same time the contact area between the FMM and the positive spacer 128 or the spherical spacer 126 It is possible to improve the foreign matter phenomenon caused by the contact between the FMM and the spacer.

On the other hand, when both the positive spacer 128 and the spherical spacer 126 are formed, the contact with the FMM occurs only in the positive spacer 128, so that the foreign matter phenomenon can be minimized and the peeling phenomenon of the organic layer 118 can be improved .

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Will be clear to those who have knowledge of.

100: substrate 101: buffer layer
102: gate electrode 104: semiconductor layer
106: gate insulating film 109a, 109b: source / drain region
108: drain electrode 110: source electrode
112: first protective film 113, 122: contact hole
114: second protective film 116: first electrode
118: organic layer 120: second electrode
124: bank insulating film 126: spherical spacer
127: inorganic film 128: positive spacer
129: organic film 130: barrier layer
132: conductive nanoparticles 134: hydrophobic polymer compound

Claims (6)

A first electrode positioned on the substrate;
A bank insulating layer including an organic hole exposing a first electrode on a substrate having the first electrode;
A spherical spacer positioned on the bank insulating film,
An organic layer including a first electrode exposed through the organic hole, and a light emitting layer disposed on the bank insulating film and the spherical spacer,
And a second electrode located on a front surface of the substrate including the bank insulating layer and the organic layer. The method according to claim 1,
Further comprising a barrier layer located on a front surface of the substrate including the organic layer and the second electrode. The method according to claim 1,
Wherein the bank insulating film and the spherical spacer are made of a hydrophobic thermosetting resin. The method according to claim 1,
Wherein the spherical spacer is made of conductive nanoparticles coated with a hydrophobic polymer compound, and the bank insulating film is made of a hydrophobic thermosetting resin. The method according to claim 1,
Further comprising a positive spacer located on an upper portion of the bank insulating film which is another region on the same plane as the region where the spherical spacer is located. 6. The method of claim 5,
And the height of the positive spacer is higher than that of the spherical spacer.

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