KR100861267B1 - Metal Mask - Google Patents

Abstract

The present invention relates to a metal mask capable of manufacturing a high-definition display device as well as minimizing the spread due to the shadow effect when the organic light emitting layer is deposited.

According to the present invention, a metal mask used for depositing an organic light emitting material on a substrate for manufacturing an organic light emitting display device may include holes for depositing the organic light emitting material and a predetermined distance from the substrate during the deposition of the organic light emitting material. A plurality of protrusions are formed around the holes to maintain the protrusions, and the protrusions include a material capable of responding to a magnetic force.

According to this configuration, the metal mask according to the present invention can form an organic light emitting layer having a regular pattern while maintaining a constant distance between the metal mask and the transparent substrate by forming a magnetic protrusion on the surface of the metal mask corresponding to the transparent substrate. Can be. In addition, by forming the projection away from the location of the partition wall, it is possible to reduce the spread of the organic material due to the shadow effect and to achieve high definition.

Description

Metal Mask {Metal Mask}             

1 is a view schematically showing a general organic electroluminescent display device.

2 is a perspective view showing a partial region of an organic EL display device according to the prior art;

FIG. 3 is a diagram showing a cross section of the organic EL display element shown in FIG. 2; FIG.

4 is a diagram showing a concept of light emitting pixel formation in an organic EL display element.

5A to 5D illustrate a method for manufacturing an organic light emitting layer of an organic EL display device according to the prior art.

6 is a view showing a metal mask for manufacturing an organic electroluminescent display device according to a first embodiment of the present invention.

FIG. 7 is a cross-sectional view of the metal mask shown in FIG. 6 cut with a line "A-A '". FIG.

8A to 8D are views for explaining a method for manufacturing an organic light emitting layer of an organic EL display device using the metal mask shown in FIG. 6.

9 to 12 are cross-sectional views showing metal masks of the organic EL display elements according to the second to fifth embodiments of the present invention.

<Brief description of symbols for the main parts of the drawings>

1: transparent substrate 2: anode

3: cathode 4,20,56: organic EL layer

12,50: transparent substrate 14,52: transparent electrode

18,54: bulkhead 22,58: metal electrode

16: insulating film 60: metal mask

62: projection 64: electromagnet

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal mask, and more particularly, to a metal mask capable of manufacturing a high definition display device while minimizing spread due to a shadow effect during deposition of an organic emission layer.

Recently, various flat panel displays have been developed to reduce weight and volume, which are disadvantages of cathode ray tubes. Such a flat panel display includes a liquid crystal display, a field emission display, a plasma display panel, and an electroluminescence (hereinafter referred to as "EL") display. Panels and the like.

In order to improve the display quality of such a flat panel display device and to attempt to make a large screen, there are active researches. Among them, the EL display panel is a self-luminous panel which emits light by itself. The EL display panel displays a video image by exciting fluorescent material using carriers such as electrons and holes.

This EL display element is roughly divided into an inorganic EL display element and an organic EL display element according to the material used. The organic EL display element requires a high voltage of 100 to 200 V and is driven at a voltage lower than that of the inorganic EL display element by about 5 to 20 V, thereby enabling direct DC low voltage driving. In addition, the organic EL display element has excellent characteristics such as wide viewing angle, high response speed, high contrast ratio, and the like, as a pixel of a graphic display, a pixel of a television image display, or a surface light source. It can be used and is suitable for next generation flat panel display because it is thin, light and good color.

1 is a view schematically showing a general organic EL display element, and FIG. 2 is a perspective view showing a partial region of an organic EL panel according to the prior art.

1 and 2, an organic EL display device forms a stripe-shaped anode 2 by chemical etching a transparent electrode on a transparent substrate 1, and thereon. The organic EL layer 4 is coated by a vacuum deposition method, and then a panel 3 is coated with a cathode 3 in a direction perpendicular to the strip-shaped anode 2. The anode transparent electrode 2 is embodied in a desired shape using a photolithography method. As the transparent electrode material, indium tin (Indium Tin) doped with indium oxide (In ₂ O ₃ ) and tin oxide (SnO ₂ ) is used. Oxide (hereinafter referred to as "ITO") is used.

In order to protect the panel manufactured as described above, a protective film is coated and sealed (5), and then the electrodes of the panel are connected to a driving circuit or a chip. That is, it is connected to the gate driver and the data driver to receive a signal from the driver to display an image.

 FIG. 3 is a view showing a cross section of the organic EL display element shown in FIG. 2, showing a panel in which a metal cap, that is, a seal cover plate, of the organic EL display element is removed.

Referring to FIG. 3, the organic EL display device includes a transparent electrode 14 arranged in a row in a strip shape on a transparent substrate 12, and a hole transport layer, a light emitting layer, and an electron transport layer stacked on the transparent electrode 14. An organic electroluminescent layer (hereinafter referred to as an "EL layer") 20 formed thereon and a cathode electrode 22 formed in a band shape on the EL layer to intersect the transparent electrode. In addition, a partition 18 formed in the same band between the cathode electrode 22 for separating the cathode electrode 22 is provided.

The organic EL panel is formed in a structure in which the organic EL layer 20 is interposed between the transparent electrode 14 having a high work function and the metal electrode 22 having a low work function on the transparent substrate 12. The transparent electrode 14 having a high work function is used as an anode to inject holes, and the metal electrode 22 having a low work function is used as a cathode to inject electrons. In this case, the transparent electrode 14 uses a transparent material having little absorption of light in the emission wavelength region in order to emit the emitted light to the outside of the light emitting panel. The metal electrode 22 is separated from the neighboring metal electrode by the partitions 18 when deposited on the organic EL layer 20.

The organic EL layer 20 is composed of a hole injection layer, a hole transport layer, an electron transport layer, and an electron injection layer sequentially stacked between the anode electrode 14 and the cathode electrode 22. Looking at their light emission principle, when a current flows between the anode and cathode electrodes 14 and 22, carriers composed of electrons and holes are injected through the hole injection layer and the electron injection layer, respectively. These carriers are transported to a light emitting layer (not shown) formed between the hole transport layer and the electron transport layer through the hole transport layer and the electron transport layer. In this case, the hole transport layer and the electron transport layer efficiently transport carriers to the light emitting material, thereby increasing the probability of light emission coupling in the light emitting layer. When the carriers are injected into the light emitting layer, excitons are generated in the light emitting layer, and the excitons generated in this manner generate light corresponding to the Polaron energy gap and thus disappear.

The light emitted from the transparent substrate 12 is formed by the organic EL layers 20R, 20G, and 20B formed of an organic material for emitting red light (R), green light (G), and blue light (B), as shown in FIG. It is emitted to the lower surface. At this time, the organic EL layers 20R, 20G, and 20B are formed by thermal evaporation deposition of organic materials for emitting light. In addition, the organic EL layers 20R, 20G, and 20B are formed by using a metal mask inside the evaporator to form respective organic materials for light emission.

5A to 5D are views for explaining a method for manufacturing an organic light emitting layer of an organic EL display device according to the prior art.

5A to 5D, first, the transparent electrodes 14 arranged in a band form on the transparent substrate 12 of the organic EL panel and the same band shape to separate the metal electrodes 22 to be formed in a later process. An insulating film 16 for interlayer insulation is formed between the partition wall 18 and the transparent electrode 14 and the partition wall 18. Thereafter, the transparent substrate 12 configured as described above is introduced into a deposition machine (not shown). A metal mask 26 for depositing one organic light emitting material among red (R), green (G), and blue (B) organic materials on the transparent substrate 12 introduced into the evaporator is arranged. At this time, the metal mask 26 has holes (not shown) corresponding to one pixel size in the organic EL panel having a pixel array of stripe type.

First, the metal mask 26 is arranged in the region for forming the red (R) organic EL layer 20R. Thereafter, when the red organic light emitting material is deposited on the region, the red organic EL layer 20R is formed as shown in FIG. 5A.

When the red organic EL layer 20R is formed, the metal mask 26 is shifted by one pixel cell region. When the green organic light emitting material is deposited using the shifted metal mask 26, the green organic EL layer 20G is formed as shown in FIG. 5B.

When the green organic EL layer 20G is formed, the metal mask 26 is further shifted by one pixel cell region. When the blue organic light emitting material is deposited using the shifted metal mask 26, the blue organic EL layer 20B is formed as shown in FIG. 5C.

When the organic EL layers 20R, 20G, and 20B are formed through the above process, the organic EL display element is completed by depositing the metal electrode 22 as shown in Fig. 5D.

At this time, as the interval between the metal mask 26 and the transparent substrate 12 is narrower, the spread of the organic light emitting material due to the shadow effect can be reduced. However, in the organic EL display device according to the related art, when the metal mask 26 and the transparent substrate 12 are brought into close contact with each other, the partition 18 may be damaged by the metal mask 26. In addition, since the transparent substrate 12 and the metal mask 26 are spaced apart from each other, it is difficult to maintain a constant gap therebetween. As a result, there is a disadvantage in that the pixels become non-uniform during deposition of the organic EL layer 20 of the organic EL display device.

Accordingly, it is an object of the present invention to provide a metal mask that forms fine organic projections on the surface of the metal mask to form a uniform organic light emitting layer and enables high definition.

In order to achieve the above objects, according to the present invention, a metal mask used for depositing an organic light emitting material on a substrate for manufacturing an organic electroluminescent display device includes holes for depositing the organic light emitting material and a process of depositing the organic light emitting material. A plurality of protrusions are formed around the holes to maintain a predetermined distance from the substrate, and the protrusions include a material capable of reacting to a magnetic force.
The protrusions are positioned opposite to the evaporator with the substrate interposed therebetween, and the evaporator is provided with a plurality of electromagnets for generating the magnetic force at positions corresponding to the protrusions.
The protrusions are selectively attached to or detached from the substrate by the presence or absence of magnetic force of the electromagnet.
The protrusions are formed to be the same as or higher than the partition wall for separating the cathode electrode of the organic light emitting display device.
The height of the protrusions is characterized in that 4 to 5㎛.
Each of the protrusions includes one of cylindrical, hemispherical, spherical, cuboid and triangular pyramid, and has a uniform height.
When the substrate is attached to the substrate, the protrusions are positioned in regions not overlapping the partition walls.
Other objects and features of the present invention in addition to the above object will become apparent from the description of the accompanying examples.

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Hereinafter, exemplary embodiments of the present invention will be described with reference to FIGS. 6 to 12.

FIG. 6 is a view showing a metal mask for manufacturing an organic electroluminescent display device according to a first embodiment of the present invention, and FIG. 7 is a view showing a cross section taken along line A-A 'of the metal mask shown in FIG. to be.

6 and 7, the metal mask 60 for manufacturing an organic EL display device according to the present invention includes holes 64 for depositing an organic light emitting material and metal masks having a cylindrical shape around the holes. 60. Embossings 62 formed on the surface.                     

The holes 64 have a size corresponding to one pixel cell area in an organic EL display element having a pixel cell structure of a stripe arrangement. The organic EL display device forms an organic EL layer by depositing an organic light emitting material corresponding to each color through the holes 64.

The protrusions 62 are formed by spot welding, which is a form of electric resistance welding, of a metal material around the holes 64 to form a predetermined gap between the substrate of the organic EL display device and the metal mask 60. To keep. In detail, when the metal mask 60 and the protrusion 62 to be bonded are tasted and a current is applied while applying an appropriate mechanical pressure, heat of resistance is generated, by using the metal mask 60 and the protrusion 62. To be bonded.

The height of the projection 62 is the same as or higher than that of the partition (not shown) of the organic EL display element, and is about 4 to 5 mu m. The position of the protrusion 62 is designed to avoid interference with the pattern when the metal mask 60 and the substrate are bonded to each other. In addition, the material of the protrusion 62 may be a magnet or a magnetic material, and a metal material may be used as the magnetic material.

Further, in the organic EL display device according to the present invention, an electromagnet (not shown) is provided in the evaporator for depositing the organic EL layer in order to use the metal mask 60 having the projections 62 formed thereon. The position of the electromagnet is locally attached to the same position as the projection 62, and the electromagnet forms a uniform magnetic field. The electromagnet formation position in the evaporator is a corresponding position so as to accurately contact the projection formed in the alignment mask. This prevents the metal mask from bending toward the transparent substrate by the magnetic force of the electromagnet in the evaporator.

8A to 8D are views for explaining a method of manufacturing an organic light emitting layer of an organic EL display device using the metal mask shown in FIG. 6.

8A to 8D, first, the same strip shape is used to separate the transparent electrodes 52 arranged in a strip shape on the transparent substrate 50 of the organic EL display element and the metal electrodes 58 to be formed in a later process. An insulating film (not shown) for interlayer insulation is formed between the partition wall 54 and the transparent electrode 52 and the partition wall 54. Thereafter, the transparent substrate 50 configured as described above is introduced into a deposition machine (not shown). The metal mask 60 having the projections 62 formed thereon for depositing one organic light emitting material among red (R), green (G) and blue (B) colors on the transparent substrate 50 introduced into the evaporator is provided. Are arranged. In this case, the metal mask 60 has holes 64 corresponding to one pixel size in the organic EL panel having a pixel array of stripe type.

First, a metal mask 60 is arranged on the transparent substrate 50 to form a red (R) organic EL layer 56R. In this case, the metal mask 60 includes protrusions 62 to maintain a predetermined distance from the transparent substrate 50 on a region corresponding to the transparent substrate 50. In addition, an electromagnet 66 disposed on a deposition apparatus for supporting the protrusions 62 and preventing the transparent substrate 50 from bending by magnetic force is provided on the rear surface of the transparent substrate 50. Located. When the red organic light emitting material is deposited through the metal mask 60, the red organic EL layer 56R is formed as shown in FIG. 8A.

When the red organic EL layer 56R is formed, the metal mask 60 is shifted by only one pixel cell region. When the green organic light emitting material is deposited using the shifted metal mask 60, the green organic EL layer 56G is formed as shown in FIG. 8B.

When the green organic EL layer 56G is formed, the metal mask 60 is further shifted by one pixel cell region. When the blue organic light emitting material is deposited using the shifted metal mask 56, a blue organic EL layer 56B is formed as shown in FIG. 8C.

In depositing the organic EL layers 56R, 56G, and 56B in the above process, the electromagnet 66 attached to the evaporator is turned on to closely contact the metal mask 60 and the transparent substrate 50, and after the deposition is completed, The electromagnet 66 is turned off to detach the metal mask 60 from the transparent substrate 50.

When the organic EL layers 56R, 56G, and 56B are formed through the above process, the organic EL display device is completed by depositing the metal electrode 58 as shown in Fig. 8D.

Through this configuration, when a current flows between the transparent electrode 52 and the metal electrode 58, an organic EL layer 56R, 56G, 56B deposited between the electrodes when a current flows between the two electrodes 52, 58. ) Is activated when light is emitted.

9 to 12 are cross-sectional views showing metal masks of the organic EL display elements according to the second to fifth embodiments of the present invention.

9 to 12, the metal mask 60 of the organic EL display device according to the second to fifth embodiments of the present invention has protrusions 62 on the surface in the same manner as in FIG.

The protrusions 62 may have various shapes such as hemispherical shape in FIG. 9, spherical shape in FIG. 10, rectangular parallelepiped shape in FIG. 11, and triangular pyramid shape in FIG. 12. In this case, the materials of the protrusions 62 are magnets or magnetic materials, and a metal material is mainly used. In addition, the heights of the protrusions 62 are the same as or larger than those of the partition wall 54 as described in FIG. 6, and are formed about 4 to 5 μm.

As described above, the metal mask for manufacturing the organic electroluminescent display device according to the present invention and the organic light emitting layer manufacturing method using the same according to the present invention are formed between the metal mask and the transparent substrate by forming magnetic protrusions on the surface of the metal mask corresponding to the transparent substrate. It is possible to form an organic light emitting layer having a regular pattern while maintaining the gap. In addition, by forming the projection away from the location of the partition wall, it is possible to reduce the spread of the organic material due to the shadow effect and to achieve high definition.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the technical spirit of the present invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification but should be defined by the claims.

Claims (10)

In the metal mask used to deposit an organic light emitting material on a substrate for manufacturing an organic electroluminescent display device, Holes for depositing the organic light emitting material, It is provided with a plurality of protrusions formed around the holes to maintain a predetermined distance from the substrate during the deposition process of the organic light emitting material, The projections of the metal mask, characterized in that it comprises a material capable of reacting to the magnetic force. delete The method of claim 1, The protrusions are located opposite the evaporator with the substrate interposed therebetween, The evaporator is provided with a plurality of electromagnets for generating the magnetic force in a position corresponding to the protrusions, the metal mask. The method of claim 3, wherein The protrusions are selectively removable to the substrate by the presence or absence of magnetic force of the electromagnet. delete The method of claim 1, The projections are metal mask, characterized in that formed in the same or higher than the partition walls for separating the cathode of the organic electroluminescent display device. The method of claim 6, The height of the protrusions is a metal mask, characterized in that 4 to 5㎛. The method of claim 1, Each of the protrusions includes any one of a cylinder, a hemispherical shape, a spherical shape, a cuboid shape, and a triangular pyramid, wherein the metal mask has a uniform height. delete The method of claim 6, When the substrate is bonded to the substrate, the protrusions are positioned in areas not overlapping with the partition walls.

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