JP3652136B2 - Organic EL display panel and manufacturing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an organic electroluminescence (hereinafter referred to as organic EL) display panel, and more particularly to an organic EL display panel used as a display device.
[0002]
[Prior art]
In general, an organic EL medium is very sensitive to moisture. Therefore, in an organic EL display panel, an organic EL element is sealed with a sealing body such as a sealing can to prevent moisture from entering from the outside.
1A and 1B are diagrams showing the structure of a conventional organic EL display panel. FIG. 1A is a top view, and FIG. 1B is a cross-sectional view taken along line AA in FIG. In addition, about Fig.1 (a), it has shown about the inside which removed the sealing can.
[0003]
The organic EL display panel in FIG. 1 includes a plurality of anodes 5 made of a transparent conductor such as indium tin oxide (ITO), a light emitting layer 7 made of an organic EL medium, and a metal material such as Al on a transparent substrate 3. And a plurality of cathodes 9 perpendicular to the anode 5 are sequentially stacked. In the light-emitting layer 7 (organic EL layer), a region where the anode 5 (transparent electrode) and the cathode 9 (metal electrode) intersect with each other serves as a light-emitting portion 11 to constitute a simple matrix display panel.
[0004]
Reference numeral 13 denotes a shell-shaped sealing can that encloses the light emitting region, and encloses dry nitrogen (N ₂ ) inside. Reference numeral 15 denotes an adhesive for fixing the sealing can and the substrate, and reference numeral 16 denotes an adhesive region.
However, in conventional organic EL display panels, if the adhesive protrudes to the light emitting part due to excessive application of adhesive, uneven application, misalignment of the sealing can, etc. during the manufacturing process, the element is damaged by the adhesive. As a result, the non-light emitting portion (dark spot) is enlarged, the brightness is significantly reduced, and the manufacturing yield is reduced.
[0005]
In order to prevent this, there can be considered a method in which the distance between the element portion and the adhesion region is sufficiently large. However, this will increase the dead space of the panel.
[0006]
[Problems to be solved by the invention]
The present invention has been made in view of the above points, and the object of the present invention is to prevent the intrusion of the adhesive into the light emitting part without expanding the dead space of the panel and to enable stable production with a good yield. An organic EL display panel is provided.
[0007]
[Means for Solving the Problems]
In the present invention, at least a transparent electrode, an organic EL material layer, and a metal electrode are sequentially laminated on a substrate, and an intersection of the transparent electrode and the metal electrode becomes a light emitting region and is fixed to the substrate with an adhesive. An organic EL display panel including a sealing body that seals a light emitting region together with a substrate , wherein a protective wall protruding from the substrate is provided between the light emitting region and an adhesive portion of the sealing body, The protective wall is made of the same material . According to this, since the protective wall is provided between the light emitting region and the bonding portion of the sealing body, it is possible to prevent the adhesive from entering the light emitting portion.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below in detail with reference to the drawings.
As shown in FIG. 2, the organic EL display panel according to the embodiment of the present invention has an image display array composed of a plurality of light emitting pixels 1 which are arranged in a matrix and each is composed of red R, green G and blue B light emitting portions. have. In addition, a monochrome display panel can be formed by replacing all the RGB light emitting portions with a single color light emitting portion.
[0009]
FIG. 3 schematically shows the configuration of an organic EL display panel according to the first embodiment of the present invention. FIG. 3A is a top view, and FIG. 3B is a cross-sectional view taken along line AA in FIG. In addition, about Fig.3 (a), it has shown about the inside which removed the sealing can.
As shown in FIG. 3, a transparent electrode 5 made of a transparent conductor such as indium tin oxide (ITO) is provided on the transparent substrate 3 of the organic EL display panel. The transparent electrodes 5 are arranged in a plurality of stripes parallel to each other at a predetermined interval.
[0010]
On the transparent electrode 5, a thin film of at least one layer of the organic EL medium 7 is formed. For example, the organic EL medium 7 is a single layer of an organic light emitting layer, or a medium having a three-layer structure of an organic hole transport layer, an organic light emitting layer and an organic electron transport layer, or two layers of an organic hole transport layer and an organic light emitting layer. For example, a medium with a structure.
On the thin film of the organic EL medium 7, a metal electrode 9 extending in the direction perpendicular to the transparent electrode 5 is formed. The metal electrodes 9 are arranged in a plurality of stripes parallel to each other at a predetermined interval. In this way, each of the regions where the transparent electrode 5 and the metal electrode 9 intersect and sandwich the organic EL medium becomes the light emitting unit 11 (unit pixel). A protective wall 21 is provided between the light emitting region and the adhesive region 16 so as to surround the entire light emitting region composed of the light emitting units 11 arranged in a matrix between the light emitting region and the adhesive region 16. 9 except for the above.
[0011]
Below, the outline is demonstrated about the manufacturing process of the organic electroluminescent display panel of the said Example.
First, a plurality of transparent electrodes 5 (for example, 0.3 mm pitch, 0.28 mm width, 0.2 μm film thickness) made of a transparent conductor such as ITO are formed in parallel on the transparent substrate 3 by a patterning process.
[0012]
Next, the protective wall 21 is formed. In this protective wall forming step, a non-photosensitive polyimide as a protective wall material is formed on the substrate by, for example, spin coating. Next, using a normal photolithography method, a resist mask is formed at a position surrounding the entire light emitting region inside the adhesive region 16 as shown in FIG. Subsequently, the protective wall 21 is formed by etching polyimide that is not masked by dry etching or wet etching.
[0013]
Incidentally, what has been referred to as polyimide so far is a substance in a precursor state before imidization, and of course it becomes a real polyimide when cured by heat treatment. However, if there are no inconveniences such as strength, the material need not be cured. Further, the material is not limited to polyimide, and an insulating material that can maintain strength without being etched in a subsequent process can be used.
[0014]
Next, in the formation process of the light emitting layer 7, after aligning and mounting the light emitting layer film-forming mask, the first (for example, red) organic EL medium is deposited using a method such as vapor deposition. A film is formed to a predetermined thickness. Next, after the light emitting layer deposition mask is shifted and positioned by one pixel, the second (for example, green) organic EL medium is deposited to a predetermined thickness. Further, the light emitting layer film formation mask is shifted by one pixel, aligned, and placed, and then a third (for example, blue) organic EL medium is formed to a predetermined film thickness.
[0015]
After forming RGB three types of organic EL media at predetermined locations, the light emitting layer deposition mask is replaced with a metal electrode deposition mask, and metal vapor is deposited on each of the organic EL media by, for example, vapor deposition. By applying, a plurality of metal electrodes 9 arranged in a stripe shape are formed.
Finally, the light emitting region is sealed by fixing the sealing can 13 to the substrate 3 with an adhesive.
[0016]
As shown in FIG. 3, the protective wall does not necessarily need to be provided around the inside of the adhesive portion, and may be formed only in a portion where the protrusion is particularly likely to occur in the adhesive application process, for example, a corner portion.
FIG. 4 is a top view schematically showing a configuration of an organic EL display panel according to the second embodiment of the present invention. FIG. 4 shows the organic EL medium with the thin film and the metal electrode removed.
[0017]
As shown in FIG. 4, a plurality of protective walls 23 and 25 are formed only at each corner portion of the panel. The protective wall 23 has a hook-like portion 23a that is bent in accordance with the corner portion so that the adhesive protruding from the corner portion of the adhesive region 16 does not reach the light emitting region. Further, the protective wall 25 is arranged so as to have a gap in parallel with the protective wall 23, and is configured such that the adhesive leaking out from the adhesion region 16 flows out along the gap. As shown in the figure, since the extension direction of the gap between the protective walls 23 and 25 is not directed to the light emitting region, even if a large amount of leaked adhesive is present, the gap extends along the gap. Since it flows in the direction, the adhesive does not reach the light emitting region. The protective wall of the present embodiment can be formed by the same process as that of the first embodiment described above.
[0018]
FIG. 5 is a top view schematically showing a configuration of an organic EL display panel according to a third embodiment of the present invention, in which the thin film and the metal electrode of the organic EL medium are removed. This embodiment shows the case where the partition wall 28 for metal electrode patterning disclosed in JP-A-8-315981 is formed, and other configurations are the same as those of the second embodiment described above. As shown in the figure, the partition wall 28 extends in a direction orthogonal to the transparent electrodes 5 arranged in a plurality of stripes parallel to each other at a predetermined interval. By forming the partition wall 28 in this way, when a metal material is deposited on the substrate 3 after forming a thin film of an organic EL medium, a plurality of striped metal electrodes are formed in the gap of the partition wall 28. be able to. In the present embodiment, the partition wall 28 is formed of the same non-photosensitive polyimide as the protective walls 23 and 25, and the manufacturing process thereof is performed in the same process as the above-described protective wall manufacturing process. Thereby, not only the material cost can be reduced, but also the steps such as film formation and etching of the non-photosensitive polyimide can be performed at the same time, thereby reducing the manufacturing cost.
[0019]
Next, the case where an organic EL display panel is produced based on the third embodiment shown in FIG. 5 will be specifically described.
An organic EL display panel in which ITO was formed to a thickness of 1000 angstroms and patterned into a predetermined shape was formed with a protective wall and partition walls for patterning metal electrodes. First, after sufficiently washing the substrate, partition walls 28 were formed at a height of 6 μm in the portion corresponding to the gap of the metal electrode pattern. At the same time, protective walls 23 and 25 were formed in the inner part of the corner of the sealing portion. While rotating this substrate, TPD was deposited at 700 angstroms and Alq ₃ was deposited at 550 angstroms, and then the rotation of the substrate was stopped and Al—Li alloy was deposited at 1000 angstroms. Furthermore, the sealing can was adhered and sealed with a UV curable adhesive.
[0020]
When 100 such organic EL display panels were produced and the protrusion of the adhesive was observed, the number of the panels where the protrusion of the adhesive reached the light emitting portion was zero. Nine panels had large adhesive sticking out, but the protective wall stopped sticking out.
On the other hand, as a comparative example, when 100 protective panels 23 and 25 were not provided and 100 identical panels were prepared for all other configurations, the adhesive protrusion of 7 panels was found to be defective. When these defective panels were driven, dark spots were greatly progressed in the light emitting portion where the adhesive flowed out, and it was not practical.
[0021]
FIG. 6 is a side view showing an organic EL display panel according to the fourth embodiment of the present invention. As shown in the figure, in the present embodiment, the protective wall 23 is formed so that the cross section is substantially reverse tapered, so that the leaked adhesive does not easily get over the protective wall 23 and is bonded. The effect of preventing the outflow of the agent is greater.
7 and 8 are top views schematically showing protective walls of organic EL display panels according to the fifth and sixth embodiments of the present invention. In these embodiments, the protective walls 30 and 31 are configured to have a gap that causes capillary action.
[0022]
FIG. 9 is a top view schematically showing a configuration of an organic EL display panel according to a seventh embodiment of the present invention. A plurality of linear protective walls 33 are formed at opposite sides of each corner.
FIG. 10 is a top view schematically showing a configuration of an organic EL display panel according to the eighth embodiment of the present invention. The present embodiment is different from the above-described embodiment in that the protective wall 35 is formed after the transparent electrode 5, the organic EL medium 7 and the metal electrode 9 are formed on the substrate 3, and the light emitting units 11 arranged in a matrix form. The protective wall 21 is provided between the bonding region 16 and the entire light emitting region.
[0023]
As described above, according to the present invention, even when the adhesive protrudes, it is possible to prevent the adhesive from entering the light emitting portion and realize an organic EL display panel in which the light emitting portion is not damaged. it can.
In addition, the protective wall shown in the above-mentioned Example is an illustration, can be applied in various deformation | transformation, and may be used in various combinations.
[0024]
【The invention's effect】
As described in detail above, according to the present invention, an organic EL display panel capable of preventing the adhesive from entering the light emitting portion without expanding the dead space of the panel and achieving stable production with a high yield is realized. it can.
[Brief description of the drawings]
1A and 1B are a top view and a cross-sectional view showing an example of a structure of a conventional organic EL display panel.
FIG. 2 is a partially enlarged plan view illustrating light emitting pixels in an organic EL display panel according to an embodiment of the present invention.
FIGS. 3A and 3B are a top view and a cross-sectional view schematically showing a configuration of an organic EL display panel according to a first embodiment of the present invention. FIGS.
FIG. 4 is a top view schematically showing a configuration of an organic EL display panel according to a second embodiment of the present invention.
FIG. 5 is a top view schematically showing a configuration of an organic EL display panel according to a third embodiment of the present invention.
FIG. 6 is a cross-sectional view of an organic EL display panel according to a fourth embodiment of the present invention.
FIG. 7 is a top view schematically showing a protective wall of an organic EL display panel according to a fifth embodiment of the present invention.
FIG. 8 is a top view schematically showing a protective wall of an organic EL display panel according to a sixth embodiment of the present invention.
FIG. 9 is a top view schematically showing a configuration of an organic EL display panel according to a seventh embodiment of the present invention.
FIG. 10 is a top view schematically showing a configuration of an organic EL display panel according to an eighth embodiment of the present invention.
[Explanation of main part codes]
DESCRIPTION OF SYMBOLS 3 Transparent substrate 5 Transparent electrode 7 Organic EL medium 9 Metal electrode 11 Light emission part 13 Sealing can 15 Adhesive material 16 Adhesion area | region 21,23,25,30,31,35 Protection wall 28 Partition

Claims (4)

A substrate, a plurality of transparent electrodes formed on the substrate, a plurality of metal electrode patterning partition walls exposing at least a part of the transparent electrode, and at least one formed on each of the exposed portions of the transparent electrode An organic EL material layer, and a plurality of metal electrodes formed on the organic EL material layer, wherein a plurality of intersections of the transparent electrode and the metal electrode serve as a light emitting region, and An organic EL display panel including a sealing body that is fixed to a substrate with an adhesive and seals the light emitting region together with the substrate, wherein the substrate is disposed between the light emitting region and an adhesive portion of the sealing body. The organic EL display panel is provided with a protective wall protruding from the wall, and the partition and the protective wall are made of the same material . The organic EL display panel according to claim 1 , wherein the protective wall has a substantially inverted tapered cross section. 3. The organic EL display panel according to claim 1, wherein the protective wall has a gap that causes capillary action on the adhesive. On the substrate, at least a transparent electrode, an organic EL material layer, and a metal electrode are sequentially laminated, and an intersection of the transparent electrode and the metal electrode serves as a light emitting region, and is fixed to the substrate with an adhesive. A method of manufacturing an organic EL display panel comprising a sealing body that seals the light emitting region together with a substrate, wherein a plurality of the transparent electrodes are formed on the substrate, a transparent electrode forming step, and at least a part of the transparent electrodes. A barrier rib forming step of forming a metal electrode patterning barrier rib that protrudes entirely from the substrate, and an organic EL material is deposited on each of the exposed portions of the transparent electrode, and the at least one layer of organic EL material Forming an organic EL material layer, and forming a plurality of the metal electrodes divided by the partition on each of the organic EL material layers A protective wall forming step of forming a protective wall projecting from the substrate between the light emitting region and the bonding portion of the sealing body, and a sealing for fixing the sealing body to the substrate with an adhesive It is seen including a stop member bonding step, wherein the partition wall and the protective wall is consisted of the same material, the organic EL display panel, wherein the partition wall forming step and the protective wall forming process are performed simultaneously Production method.

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