KR20170041370A - Luminescence dispaly panel - Google Patents

Abstract

The present invention relates to a light emitting display panel which can prevent peeling of an organic layer and can be manufactured without damage to an organic layer during a manufacturing process, and a method of manufacturing the same. In the organic light emitting display panel according to the present invention, Or an inverted trapezoidal shape including protrusions is provided on the upper portion of each bank insulating film to suppress the peeling of the organic layer through the inverse spacer and to minimize the contact between the inverse spacer and FMM (fine metal mask) .

Description

[0001] LUMINESCENCE DISPALY PANEL [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a light emitting display panel, and more particularly, to a light emitting display panel capable of preventing peeling of an organic layer by providing an inverse spacer and preventing an organic layer from being damaged 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 It is an object of the present invention to provide an OLED device in which foreign matter generated on a contact surface between an FMM and an inverse spacer is minimized by minimizing a contact surface between FMM and an inverse spacer by changing the structure of an inverse spacer This is a problem to be solved.

In order to solve the above problems, an organic light emitting diode display panel according to the present invention includes an inverted trapezoidal shape having a vertically cut cross section on a top thereof with grooves or protrusions on an upper portion of a bank insulating layer.

At this time, at least one protrusion provided on the reverse spacer may be at least one, and if the reverse spacer has a groove, the center may be concave at the center of the groove.

The top surface of the reverse spacer may be circular or elliptical, and may be formed in various shapes such as a triangle, a square, and the like.

The organic light emitting display panel according to the present invention has an inverse spacer having a groove at the center or at least one protrusion and minimizing the contact area between the FMM and the reverse spacer when forming the organic layer, It is possible to minimize the foreign matter generated by the contact between the inverse spacer and the FMM.

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.
FIGS. 3 to 7 are diagrams for explaining various forms of the reverse spacer 126 that may be included in the light emitting display panel according to the present invention.
8A to 8I are diagrams for explaining a method of forming a 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.

2 is a cross-sectional view illustrating a structure of a light emitting display panel according to the present invention.

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 an emissive layer formed on the first electrode 116 exposed through the organic hole and an organic layer 118 formed on the organic insulating layer 124, (120).

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.

The cross section cut in the vertical direction of the reverse spacer 126 has an inverted trapezoidal shape having a groove at the central portion or a protrusion at the upper portion. The organic layer 118 and the second electrode 120 are also disposed on the reverse spacer 126.

A barrier layer 130 is located on the second electrode 120. The barrier layer 130 has a structure in which at least one of the inorganic film 127 and the organic film 129 is stacked and crossed.

The organic layer 118 formed on the bank insulating film 124 is not formed at the point where the reverse spacer 126 and the bank insulating film 124 are in contact with each other and is not formed on the side surface of the reverse spacer 126. [ The organic layer 118 formed on the inverse spacer 126 and the organic layer 118 formed on the organic hole and the bank insulating film 124 are separated from each other at a position where the inverse spacer 126 and the bank insulating film 124 are in contact with each other.

When the inverse spacer 126 is formed on the bank insulating film 124 as described above, the organic layer 118 is not deposited on the side of the inverse spacer 126 and the point where the inverse spacer 126 and the bank insulating film 124 are in contact with each other 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 inverse spacer 126 and the bank insulating film 124 are in contact with each other and the inverse spacer 126 And has an effect of fixing the organic layer 118 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.

3 to 7 are diagrams for explaining various forms of the reverse spacer 126 that may be included in the light emitting display panel according to the present invention.

3 to 6, the reverse spacer 126 may be formed in a shape having a circular or oval top surface and at least one protruding portion 127.

3 is an exemplary view for explaining a case where the inverse spacer 126 has two projections 127. FIG. As shown in Figs. 3 (a) and 3 (b), two protrusions 127 may be formed on both sides of the upper surface of the inverse spacer 126. That is, the two protrusions 127 are located on two points that are most distant from each other within the upper surface of the inverse spacer 126. As shown in FIG. 3 (a), the reverse spacer 126 viewed from the top surface may be circular or elliptical.

Fig. 4 is an illustration showing a case where the inverse spacer 126 has three protrusions 127. Fig. As shown in FIG. 4A, the reverse spacer 126 viewed from the top surface is circular or elliptical. As shown in FIG. 4B, three protrusions are formed on the upper surface of the circular reverse spacer 127 It can be located on three sides by dividing the circumference into three.

The three protrusions 127 may be located on three points that are most distant from each other within the top surface of the inverse spacer 126.

5 is an exemplary view illustrating a case in which the inverse spacer 126 has four protrusions 127. FIG. As shown in FIG. 5A, the reverse spacer 126 viewed from the upper surface is circular or elliptical. As shown in FIG. 5B, the four protrusions 127 protrude from the inverse spacer 127 It can be placed on four sides by dividing the circumference of the upper surface into four equal parts. That is, the four protrusions 127 may be located on four points that are most distant from each other within the upper surface of the inverse spacer 127.

6 is an exemplary view for explaining a case where the inverse spacer 126 has the groove 128. FIG. 6 (a), the reverse spacer 126 viewed from the top surface is circular or elliptical, and as shown in FIG. 6 (b), a groove 128 is provided at the center of the reverse spacer 126 do.

7 is an exemplary view for explaining the shape of various reverse spacers.

7A to 7C, the reverse spacer 126 viewed from the top surface may be in the form of a rectangle, a triangle, or a rhombus. 3 to 6, the inverse spacer 126 may have at least one protrusion or may have a groove at the center.

As such, the shape of the inverse spacer 126 may vary according to its design.

Hereinafter, a method of forming a light emitting display panel according to the present invention will be described with reference to the drawings.

8A to 8I are diagrams for explaining a method of forming a light emitting display panel according to the present invention.

Referring to FIG. 8A, 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.

 8B, 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. Referring to FIG. 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. 8C, a first protective film 1 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 so as to expose the source / drain regions 109a and 109b through a photolithography process and an etching process.

Referring to FIG. 8D, 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.

 Referring to FIG. 8E, a second passivation layer 114 including a contact hole 122 is deposited on a first passivation layer 112 including a source electrode 110 and a 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. 8F, a first electrode 116 is formed on the second protective film 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.

8G, a bank insulating layer 124 including an organic hole 140 is formed on a substrate 101 on which a first electrode 122 is formed.

Specifically, the bank insulating layer 124 is formed on the entire surface of the substrate 101 on which the first electrode 122 is formed by coating the photosensitive organic insulating material through a coating method such as spin-spin coating or spin coating. An organic hole 140 is formed by exposing the first electrode 122 by patterning the bank insulating film 124 by a photolithography process and an etching process.

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 . And the reverse spacer 126 is formed by patterning the organic insulating layer by a photolithography process and a patterning process.

In order to form the inverse spacer 126, the organic insulating layer is sequentially subjected to a pre-baking process, a photolithography process, a patterning process, a hard baking process, and an etching process so that the reverse spacer 126 has an inverted trapezoidal shape So that the taper of the reverse spacer 126 can be adjusted.

Further, in the photolithography process for forming the inverse spacer 126, a halftone mask is used so that the upper surface has a step.

8H, an organic layer 126 and a second electrode 128 are sequentially formed on a substrate 101 on which a bank insulating layer 124 including an organic hole 140 is formed.

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 inverse spacer 126.

At this time, since the FMM is partially in contact with only a part of the region except for the groove 128 at the top of the protrusion 126 or the reverse spacer 126 provided in the reverse spacer 126, The generation of foreign matter to be formed is remarkably reduced.

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. 8I, 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.

As described above, the organic light emitting display panel according to the present invention has the inverse spacer 126 having the groove at the center or at least one protrusion and the contact area between the FMM and the reverse spacer 126 when the organic layer 118 is formed It is possible to improve the peeling phenomenon of the organic layer 118 occurring in the foldable display and to minimize the foreign matter generated by the contact of the inverse spacer 126 and the FMM.

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: reverse spacer
127: inorganic film 129: organic film
130: barrier layer

Claims (10)

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;
An inverse spacer located 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 layer and the inverse spacer,
And a second electrode located on the entire surface of the substrate including the bank insulating film and the organic layer,
Wherein the cross section cut in the vertical direction of the reverse spacer has an inverted trapezoidal shape with a groove at the center or at least one protrusion on the upper side. 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,
The inverse spacer
Wherein the organic light emitting display panel has a central portion recessed from the center of the groove. The method according to claim 1,
The inverse spacer
And at least one protrusion on the upper surface. 5. The method of claim 4,
Wherein the reverse spacer has first and second projections,
Wherein the first and second protrusions are located on two points that are most distant from each other on the upper surface. 5. The method of claim 4,
Wherein the reverse spacer has first, second and third projections,
Wherein the first to third protrusions are located on three points that are most distant from each other on the upper surface. 5. The method of claim 4,
Wherein the reverse spacer has first, second, third, and fourth protrusions,
Wherein the first to fourth protrusions are located on four points that are most distant from each other on the upper surface. 7. The method according to any one of claims 1 to 6,
Wherein the upper surface of the reverse spacer is circular or elliptical. 6. The method according to any one of claims 1 to 5,
The upper surface of the reverse spacer is a triangular- 7. The method according to any one of claims 1 to 6,
Wherein an upper surface of the reverse spacer is rectangular or rhombic.

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