KR100269390B1 - Electroluminescence display panel and method for producing thereof - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic electroluminescent display panel and a method for manufacturing the same, and to produce a full color display panel which does not require a shadow mask and at the same time does not deposit two organic layers.

The method of manufacturing an organic light emitting display panel according to the present invention includes a first step of forming a first electrode on a transparent substrate, and a plurality of first to fourth buffer layers sequentially formed in a direction perpendicular to the first electrode. A third step of forming an electrical insulation layer in the same direction on the buffer layer, a fourth step of forming a first partition wall in the same direction on the first buffer layer, the third buffer layer and the fourth buffer layer, and the first step from the first buffer layer A fifth step of forming a second partition wall in a direction perpendicular to the first partition wall on one side of the first electrode across the three buffer layers, and an organic light emitting device having red, blue, and green light emission on each of the first electrodes divided by the buffer layer; A sixth step of sequentially depositing the organic films in different directions and angles so that only one organic film of the film is laminated and on the organic film It characterized in that it comprises a seventh step of forming a second electrode, and also the present invention provides an organic light emitting display panel constituted by the above method.

Description

Organic electroluminescent display panel and manufacturing method thereof

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to display devices, and more particularly to an organic electroluminescent (EL) display panel and a method of manufacturing the same.

Recently, as the size of a display device increases, the demand for a flat display device having less space is increasing. An electroluminescent device is attracting attention as one of such flat display devices.

The electroluminescent device is largely divided into an inorganic EL device and an organic EL device according to the material used. Among these, the organic EL device charges the organic electroluminescent layer formed between the electron injection electrode (cathode) and the hole injection electrode (anode). When injected, electrons and holes are paired and extinguished while emitting light, and the research is actively conducted because it can be driven at a lower voltage (for example, 10V or less) than a plasma display panel (PDP) or an inorganic EL display. It's going on.

In addition, the organic EL device has excellent characteristics such as wide viewing angle, high speed response and high contrast, and thus can be used as a pixel of a graphic display, a pixel of a television image display or a surface light source. They are thin, light, and have good color, making them suitable for next-generation flat panel displays. In addition, the device may be formed on a flexible transparent substrate such as plastic.

1 is a structure of a simple matrix type organic EL device having such a purpose, and is formed on a first electrode 2 and a first electrode 2 formed in a stripe shape on a transparent substrate 1. The organic electroluminescent layer 4 is formed, and the second electrode 3 is formed in the form of a band in a direction perpendicular to the first electrode formed in the form of a band on the organic light emitting layer 40.

The organic light emitting layer 4 is formed on a hole injecting layer (HIL) or a hole transporting layer (HTL) formed on the first electrode 2, and is formed on the hole injection layer or the hole transporting layer. An organic light emitting layer, and an electron transporting layer (ETL) or electron injecting layer (EIL) formed on the organic light emitting layer.

The hole injection layer or the hole transport layer formed on the first electrode 2 may be a layer in which a hole injection layer and a hole transport layer are continuously formed on the first electrode 2, and an electron transport layer formed on the organic emission layer or The electron injection layer may be a layer in which an electron transport layer and an electron injection layer are continuously formed on the organic emission layer.

The second electrode 3 of the organic EL device formed as described above functions to inject electrons into the organic light emitting layer through the electron injection layer and / or the electron transport layer of the organic light emitting layer 4, and the first electrode 2. May inject holes into the organic light emitting layer through the hole injection layer and / or the hole transport layer.

However, such an organic EL device has many difficulties in manufacturing, and one of the most difficult processes is the pixelation or patterning process.

That is, ITO (Indium Tin Oxide) commonly used as the first electrode 2 strip can be easily patterned using a photolithography process commonly used in semiconductor manufacturing processes. However, the patterning of the second electrode is not so simple. When the organic electroluminescent layer 40 already formed under the second electrode 3 is exposed to water or solvent during the photolithography process, its properties deteriorate, so it is difficult to use a general photolithography process, It also shows its limits in making.

Therefore, FIGS. 2 and 3 are cross-sectional views of organic EL devices for solving the problem, and as shown in FIG. 2, a pattern is formed using a shadow mask 50 or a photoresist as shown in FIG. 3. By using a photoresist (PR), a method of forming a partition, that is, an electrical insulating layer 6, and separating the organic light emitting layer and the second electrode may be used.

First, as shown in FIG. 2, in the manufacturing method using the shadow mask, a first electrode is formed, an organic light emitting layer is formed thereon, and a shadow mask is formed thereon. Thereafter, inter pixel isolation is achieved by allowing the second electrode to be formed.

In addition, in the manufacturing method using the partition as shown in FIG. 3, first, the first electrode is formed, and the partition is formed in the direction perpendicular to the first electrode. After the organic electroluminescent layer is formed on the front surface, and the second electrode is coated on the front surface, the second electrode is naturally separated by the partition wall to insulate the pixels.

However, although it is possible to produce monochromatic organic EL displays using these methods, more sophisticated manufacturing processes and other techniques are additionally required to produce multicolor or fullcolor organic EL displays.

That is, a method of using a white light and a color filter, a method of using a blue light and a color changing medium (CCM), a method of using a partition and a shadow mask at the same time, and the like may also be considered. However, the method using the color filter and the color converting material requires a blue material having good efficiency, and a disadvantage in that the luminous efficiency decreases rapidly while passing through the color changing area.

The most efficient method of making full color organic EL devices is to deposit red, green, and blue light emitting materials separately.

The red, green, and blue organic film may be deposited as follows.

That is, one of them is a method of depositing red, blue, and green organic films using a shadow mask, respectively, as shown in FIG. 4, and the other is tilting red and blue when organic materials are deposited without using a shadow mask, using a high partition as shown in FIG. 5. , Green pixels in turn.

A deposition method using the shadow mask will be described with reference to FIG. 4.

First, the ITO strip is mainly used to form the first electrode. The barrier rib is formed thereon in a direction perpendicular to the first electrode. Next, using the shadow mask, two barrier ribs are skipped to form an organic layer 4a for emitting red light, and the organic film layer 4a for emitting red light is moved side by side in a similar manner to forming the organic layer 4a. The organic film layer 4b for emitting green light and the organic film layer 4c for emitting blue light are formed. Finally, the second electrode 3 is formed so that the inter pixel isolation is achieved.

The color pixel forming method described above has the following disadvantages.

That is, as shown in FIG. 4, three sub-pixels of red, green, and blue must be formed in a rectangular shape in one pixel, so that the size of the pattern is reduced, so that a shadow mask (metal mask) suitable for this is manufactured. The process becomes difficult, and the process becomes complicated, such as difficulty in aligning a shadow mask on a predetermined position on the partition wall.

Also, referring to FIG. 5, a method of making red, green, and blue pixels in order by tilting and depositing organic materials without a shadow mask by using a high partition wall will be described below.

First, the 1st electrode 2 in which an ITO strip | belt is mainly used is formed, and a partition is previously formed in the direction perpendicular | vertical to the said 1st electrode. The organic film 4a emitting red light is tilted to the left and deposited on the front side, and the organic film 4b emitting green is tilted to the right, and the organic film 4c emitting blue is deposited directly from above. When the second electrode 3 is formed by tilting and depositing a metal layer to the right on the formed organic electroluminescent layer, the second electrode is naturally separated by a pre-made partition wall and insulated between pixels.

However, the color pixel formation method of FIG. 5 described above has the following disadvantages.

That is, since the organic film emitting red and green light is deposited and then the organic film emitting blue light is deposited immediately above, the blue material is also deposited on the red material and the green material part. In this state, when the metal electrode is applied, the blue material part emits light, but the red material and green material part are coated with two different organic layers (red light emitting material layer + blue light emitting material layer, green light emitting material layer + blue light emitting material). Material layer), which does not emit light well. In addition, although the metal electrode is inclined to be deposited, there is a disadvantage that the insulation is not assured in this process.

The present invention has been made in view of the above problems, and an object of the present invention is to eliminate the need for precise shadow masks and to accurately align the shadow mask with a substrate, and another object of the present invention is to provide a mask. The present invention provides a method for manufacturing an organic light emitting display device in a vacuum without being exposed to the atmosphere, solvents, or aqueous solutions when making the device, and another object of the present invention is another problem of the prior art. It is an object of the present invention to provide an organic electroluminescent display panel which does not deposit two layers of other organic films and a method of manufacturing the same.

1 is a plan view of an organic light emitting display device according to a simple matrix method of the prior art,

2 to 5 are cross-sectional views of structures of an organic light emitting display device according to various embodiments of the prior art,

6A to 6C are structural diagrams and cross-sectional views of an organic light emitting display panel in which an electric insulation layer, a partition wall, and a buffer layer are shown.

7 and 8 is a schematic view showing the deposition direction and the angle of the red, blue, green organic film in the organic light emitting display panel according to the present invention,

9 is a three-dimensional view of an organic light emitting display panel showing an electrically insulating layer, a partition, and a buffer layer according to the present invention;

10 is a diagram showing the shape of an electrically insulating layer applicable to the organic light emitting display panel according to the present invention.

11 and 12 are structural cross-sectional views showing that a plurality of electrical insulating layers applied to the present invention can be formed.

Explanation of symbols for main parts of the drawings

1: transparent substrate

2: first electrode

3: second electrode

4: organic light emitting layer

4a: organic layer emitting red light

4b: organic layer emitting green light

4c: organic layer emitting blue light

5: shadow mask

6: electrical insulation layer

7a: a first partition wall for selectively depositing each red, blue, and green light emitting organic film

7b: second partition wall for selectively depositing each red, blue, and green light emitting organic film

8: buffer layer

The method of manufacturing an organic light emitting display panel according to the present invention includes a first step of forming a first electrode on a transparent substrate, and a plurality of first to fourth buffer layers sequentially formed in a direction perpendicular to the first electrode. A third step of forming an electrical insulation layer in the same direction on the buffer layer, a fourth step of forming a first partition wall in the same direction on the first buffer layer, the third buffer layer and the fourth buffer layer, and the first step from the first buffer layer A fifth step of forming a second partition wall in a direction perpendicular to the first partition wall on one side of the first electrode across the three buffer layers, and an organic light emitting device having red, blue, and green light emission on each of the first electrodes divided by the buffer layer; A sixth step of sequentially depositing the organic layers in different directions and angles so that only one of the organic layers is stacked; It comprises a seventh step of forming a second electrode.

In this case, in the sixth step, when the first organic film of the red, blue, and green light emitting organic light emitting layers is deposited by tilting in one direction, the second organic film, which is the other one, is in another direction opposite to the deposition direction of the first organic film. The third organic film, which is deposited at an angle, is another, wherein the third organic film is deposited at an angle in any one direction perpendicular to the direction in which the first and second organic films are deposited.

In addition, the present invention, in the organic light emitting display panel consisting of a first electrode, an organic electroluminescent layer, a second electrode, a plurality of first to fourth buffer layer sequentially formed in a direction perpendicular to the first electrode, the buffer layer The first barrier rib formed in the same direction on the electrically insulating layer, the first buffer layer, the third buffer layer, and the fourth buffer layer formed on the same direction, and the first electrode on one side of the first electrode from the first buffer layer to the third buffer layer. It provides an organic light emitting display panel comprising a second partition formed in a direction perpendicular to the first partition.

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

6 to 12 are schematic views or cross-sectional views showing a manufacturing process and a process diagram of an organic light emitting display device according to the present invention. First, as shown in FIG. 6, a first electrode (material is usually indium tin) is illustrated on a transparent substrate 1. Oxide (ITO) strip 2 is formed. At this time, the ITO thin film is patterned into a stripe shape by using a general photolithography process.

As shown in FIG. 6, a buffer layer 8 is formed on the front surface including the first electrode to be perpendicular to the first electrode. This buffer layer is necessary for insulation between the first electrode and the second electrode.

In addition, as the buffer layer, a polymer having good insulating properties or an inorganic material such as oxide and nitride may be used to withstand a laser.

In the present specification, for the sake of clarity, the four buffer layers sequentially formed are set as the first to fourth buffer layers, and the first to fourth buffer layers sequentially formed are sequentially formed.

Next, an electrical insulation layer 6 is formed on the buffer layer 8. The process of making the electrically insulating layer can be mostly made by a photolithography process, and the electrically insulating layer 6 can be made of one or more layers.

The material used for the electrical insulation layer 6 may be an inorganic material or a polymer. At this time, the shape of the electrical insulation layer may be any type containing an over-hang, but the representative shape of the electrical insulation layer containing the overhang will be described with reference to FIG. 10.

That is, a negative photoresist may be used as the overall electrical insulation layer of the lower narrow light form as shown in FIG. 10A, and the lower light narrow form as shown in FIG. 10B. A positive photoresist may be used as the electrical insulation layer that is connected to the lower part of the flat plate and the upper part of the flat plate. As shown in FIG. That is, an electrically insulating layer composed of two layers is possible.

In addition, the electrically insulating layer may be divided into two or more, and as a result, two or more electrically insulating layers may be formed on one buffer layer, which will be described below with reference to FIGS. 11 and 12.

That is, as shown in (a) of FIG. 11 or (a) of FIG. 12, the electrical insulation layer may be divided into two, and as shown in (b) of FIG. 12 or (b) of FIG. The insulating layer may be divided into three. Therefore, when the number of divided electric insulation layers is n, n≥1, and the electric insulation layers divided into two or more parts can maximize the insulation effect between the second electrode strips.

The shape of the electrically insulating layer shown in FIG. 11 is an electrically insulating layer having a form of lower bargain light as a whole, which is the shape of FIG. 10 (a) described above, and the shape of the electrically insulating layer shown in FIG. 12 is (b) of FIG. It is an electrical insulation layer formed by connecting the lower portion of the shape, that is, the lower light negotiation form and the upper portion of the flat plate.

Next, a first partition 7a is formed on the first buffer layer, the third buffer layer, and the fourth buffer layer in the same direction. In addition, a second partition 7b is formed on one side of the first electrode from the first buffer layer to the third buffer layer in a direction perpendicular to the first partition wall. The structures of the first and second barrier ribs 7a and 7b are continuously formed in the organic light emitting display panel as the first to fourth buffer layers are continuously formed as described above.

The barrier rib is for selectively depositing red, blue, and green organic films, and the height is preferably determined between 1 μm and 100,000 μm, and the width is preferably determined between 0.1 μm and 10,000 μm.

6 shows an organic electroluminescence in which a first electrode 2, a buffer layer 8, an electrical insulation layer 6, and partitions 7a and 7b are formed on a substrate 1 before the organic electroluminescent layer 4 is deposited. Structural diagram (a) of the display panel and cross-sectional views (b) and (c) of the structural diagram. The end (extended portion) of the bulkhead erected perpendicularly to the electrically insulating layer should not stick with the electrically insulating layer but should rise above the buffer layer, an enlarged view of which is shown in the upper right side of FIG. 6A. In other words, if the vertical distance from the electrical insulation layer to the partition wall is A and the total width of the buffer layer on one side of the electrical insulation layer is B, the end of the partition wall should not stick to the electrical insulation layer to ensure the insulation effect between the second electrodes. Therefore, A must be greater than 0, and A must be less than or equal to B since the barrier rib must rise above the buffer layer to prevent the first electrode and the second electrode from directly contacting and shorting. (0 <A≤B)

9 is a three-dimensional view of the substrate after the partition wall is formed.

Next, in order to allow only one organic film of red, blue, and green light emitting layers to be stacked on each of the first electrodes 2 divided by the buffer layer 8, The films are deposited sequentially.

This will be described in detail with reference to FIGS. 7 and 8 as follows. 7 and 8 are process diagrams illustrating the deposition direction and deposition angle of the organic layers.

That is, the organic film 4a that emits red light is inclined in one direction (left or right) of the device as in the arrow a direction of FIG. 7, and is deposited at an angle of θ as shown in FIG. 8. In this case, the angle θ may vary within a range of 1 ° to 89 ° according to the height and width of the partition wall and the width of the light emitting pixel.

Next, as shown in the arrow b direction of FIG. 7, the organic film 4b for emitting green light is not overlapped in the same cell as the organic film for emitting red light deposited by the above-described process (right or Tilt to the left) and deposit at an angle of θ ′ as shown in FIG. 8. In this case, the angle θ` may vary within a range of 1 ° to 89 ° according to the height and width of the partition wall and the width of the light emitting pixel.

In this case, the arrow b direction of FIG. 7, that is, the deposition direction of the organic film that emits green light is the opposite direction to the deposition direction of the organic film that emits red light (the arrow a direction of FIG. 7). For example, if the deposition direction arrow a of the organic film that emits red light is the deposition direction inclined to the left, the deposition direction arrow b of the organic film that emits green light is the deposition direction inclined to the right.

Then, the organic film 4c emitting blue light in the same manner is superposed together with the organic film emitting blue light in the cell in which the organic film emitting red and green light is deposited, as shown by the arrow c or c` direction of FIG. 7. Tilt in another direction (not both forward or backward) to be unsupported, depositing at an angle of θ`` as shown in FIG. 8. Another direction for preventing the red and green light emitting organic films from overlapping in the deposited cells is one of the directions perpendicular to the direction in which the red and green organic films are deposited. It can be both forward or backward. In this case, the angle θ '' may vary within a range from 1 ° to 89 °. (1 ° ≤θ``≤ 89 °)

The order and position of depositing the red, green, and blue organic films described above may be interchanged.

Next, a second electrode 3 is deposited on the deposited organic film 4 emitting red, blue, and green light. At this time, the electrical insulating layer 6 made in advance insulates the band between the second electrodes 3.

Finally, a plurality of passivation layers are formed on the second electrode to complete the organic light emitting display panel. The protective layer includes a moisture absorbing layer, a moisture proof layer, shield glass, and the like.

As described above, according to the present invention, there is no need for a precise shadow mask, accurate alignment of the shadow mask with the substrate, and exposure to an atmosphere, solvent, or aqueous solution when the device is made without the shadow mask. The organic electroluminescent device can be manufactured in a vacuum without this, and an organic electroluminescent display panel and a method of manufacturing the organic electroluminescent display panel which do not deposit two layers of different organic films, which are another problem of the prior art, can be provided.

Claims (20)

Forming a first electrode on the transparent substrate; A second step of forming a plurality of first to fourth buffer layers sequentially formed in a direction perpendicular to the first electrode; Forming an electrically insulating layer on the buffer layer in the same direction; A fourth step of forming a first barrier rib in the same direction on the first buffer layer, the third buffer layer, and the fourth buffer layer; A fifth step of forming a second partition wall in a direction perpendicular to the first partition wall on one side of the first electrode from the first buffer layer to the third buffer layer; A sixth step of sequentially depositing the organic layers in different directions and angles so that only one organic layer of red, blue, and green light emitting layers is stacked on each of the first electrodes divided by the buffer layer; ; And And a seventh step of forming a second electrode on the organic layer. The method of claim 1, wherein the sixth step is When the first organic film of the red, blue, and green light emitting organic films is deposited by tilting in one direction, the second organic film, which is the other one, is deposited by tilting in another direction opposite to the deposition direction of the first organic film. The third organic film is a method of manufacturing an organic light emitting display panel, characterized in that the deposition is inclined in any one of the direction perpendicular to the direction in which the first and second organic film is deposited. The method of manufacturing an organic electroluminescent display panel according to claim 1, wherein the deposition angles of any one of the organic films emitting red, blue, and green light are within a range of 1 ° to 89 °. The method of claim 1, further comprising forming a plurality of passivation layers on the entire surface including the second electrode. The method of claim 1, wherein the electrical insulation layer is a single layer or a plurality of layers. The method of claim 1, wherein the electrically insulating layer contains an overhang. The method of claim 1, wherein at least one electrically insulating layer is formed on one buffer layer. The method of claim 1, wherein the first and second partitions are formed higher than the electrically insulating layer. The method of claim 1. The second partition wall is a manufacturing method of an organic light emitting display panel, characterized in that separated by the second buffer layer. The method of claim 8, wherein the first and second partitions have a height of 1 μm to 100,000 μm and a width of 0.1 μm to 10,000 μm. The method of claim 9, wherein the electrically insulating layer formed on the second buffer layer does not contact the second partition wall. In the organic electroluminescent display panel consisting of a first electrode, an organic electroluminescent layer, a second electrode, A plurality of first to fourth buffer layers sequentially formed in a direction perpendicular to the first electrode; An electrical insulation layer formed on the buffer layer in the same direction; A first barrier rib formed in the same direction on the first buffer layer, the third buffer layer, and the fourth buffer layer; And a second partition formed on one side of the first electrode from the first buffer layer to the third buffer layer in a direction perpendicular to the first partition. The organic electroluminescent display panel according to claim 12, further comprising a plurality of protective films. The organic light emitting display panel of claim 12, wherein the electrical insulation layer is a single layer or a plurality of layers. 13. The organic light emitting display panel of claim 12, wherein the electrically insulating layer contains an over-hang. The organic light emitting display panel of claim 12, wherein at least one electrically insulating layer is formed in one buffer layer. The organic light emitting display panel of claim 12, wherein the first and second partitions are formed higher than the electrically insulating layer. The organic light emitting display panel of claim 12, wherein the second partition wall is separated by the second buffer layer. The organic light emitting display panel of claim 17, wherein the first and second partitions have a height of 1 μm to 100,000 μm and a width of 0.1 μm to 10,000 μm. The organic light emitting display panel of claim 18, wherein the electrical insulation layer formed on the second buffer layer does not contact the second partition wall.