JP3858707B2 - Organic EL device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an organic EL (electroluminescence) element used for a display panel or the like.
[0002]
[Prior art]
The organic EL element is used as a display panel because it has good visibility and impact resistance. As shown in FIG. 2, in the organic EL element, a transparent overcoat layer 3 is formed on a color filter 2 including a black matrix 1. On this overcoat layer 3, an anode 4 made of a transparent ITO film extending in a stripe shape in the left-right direction on the paper is formed. In addition, on the anode 4, an insulating film 5 and a partition wall 6 are laminated in a stripe shape with a direction perpendicular to the anode 4, that is, a direction perpendicular to the paper surface as a longitudinal direction. Further, an organic light emitting layer 7 made of an organic compound and a cathode 8 made of aluminum (Al) are deposited on the anode 4, the insulating film 5, and the partition wall 6 and sequentially stacked.
[0003]
Here, the insulating film 5 is provided so that the current flowing through the anode 4 can obtain a uniform current effect even below the partition wall 6. Further, the partition wall 6 has an inversely tapered slope 6a, and the metal film forming the cathode 8 is separated by vapor deposition by the inversely tapered slope 6a and the sharp upper edge 6b at the upper part of the slope 6a. The cathode 8 as a plurality of electrodes which are electrically insulated and patterned in a stripe shape can be formed.
The partition wall 6 that plays the role of dividing the cathode 8 is made of a negative type photoresist material, and in particular, a dedicated photoresist material that makes it easy to form a reverse taper shape that facilitates the division of the cathode 8 is used. As this dedicated photoresist material, for example, ELX-168C (manufactured by Nippon Zeon Co., Ltd.) is used.
As described above, when the cathode 8 is divided by the partition wall 6 and formed in a stripe shape, the anode 4 and the cathode 8 are not intersected with each other, that is, without the insulating film 5 interposed. The sandwiched organic light emitting layer 7 portion is formed as a large number of light emitting portions in a matrix form. Therefore, by selecting a specific anode 4 and cathode 8 and applying a voltage, the corresponding light emitting part can emit light.
[0004]
[Problems to be solved by the invention]
However, the barrier rib laminated surface 5a, which is the upper surface of the insulating film 5 on which the barrier ribs 6 are formed, is easily formed in a convex shape and is difficult to form flatly. When the partition wall 6 is formed on the insulating film 5 with the partition wall stacking surface 5a not flat, the shape of the reverse tapered inclined surface 6a varies in manufacturing, and the partition wall 6 having a uniform shape cannot be stably obtained. There is a problem that a part where the cathode 8 cannot be divided is generated in a part of the organic EL element.
The present invention has been made to solve such a problem, and provides an organic EL device capable of stably forming a certain inversely tapered partition wall and having the cathode surely divided into stripes. Objective.
[0005]
[Means for Solving the Problems]
The organic EL device according to claim 1 of the present invention is an organic EL device formed by sequentially laminating an organic light emitting layer and a cathode on a striped anode, and extends in a direction orthogonal to the anode. In an organic EL device in which a cathode is divided into a plurality of portions by partition walls provided on a plurality of insulating films formed in stripes, stripes are formed along the insulating film on the opposite side of the insulating film across the anode. The insulating film is made of a negative photoresist material, and the insulating film reflects part of the irradiation light for forming the insulating film by the light reflecting film. Thus , a forward tapered slope is provided at a corresponding position above the pair of light reflecting films .
In the organic EL element according to claim 2, the width of the forward tapered slope is substantially the same as the width of the light reflecting film.
The organic EL element according to claim 3 is the organic EL element according to claim 1 or 2 , wherein the light reflecting film is made of metal .
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
As shown in FIG. 1, the organic EL device according to the embodiment of the present invention includes a pair of strip-like light reflecting films 10 on a color filter 2 including a black matrix 1 in a longitudinal direction perpendicular to the paper surface. Are formed in parallel. The light reflecting film 10 is made of metal having a width of a, and is made of, for example, aluminum (Al). A transparent overcoat layer 3 is laminated on the color filter 2 on which the light reflection film 10 is disposed so as to cover the light reflection film 10. Further, on the overcoat layer 3, the light reflection film 10 is laminated. The anode 4 made of a transparent ITO film extending in a stripe shape is formed in a direction orthogonal to the horizontal direction, that is, in the horizontal direction of the paper.
[0007]
On the anode 4, the insulating film 15 having a substantially trapezoidal cross section with the forward inclined surface 15 b is formed in a stripe shape along the light reflecting film 10. The upper surface of the insulating film 15 is formed flat, and constitutes a barrier rib stacking surface 15a on which the barrier ribs 16 are stacked.
The partition wall 16 has a substantially trapezoidal cross section facing in the reverse direction as compared with the insulating film 15, and includes a reverse tapered slope 16 a extending in the longitudinal direction. The width of the bottom surface 16c of the partition wall 16 is narrower than the width of the partition wall stacking surface 15a, and both edges of the flat partition wall stacking surface 15a are exposed outside the bottom surface 16c of the partition wall 16. The insulating film 1515 and the partition 16 are both made of a negative photoresist material for the partition, for example, ELX-168C (manufactured by Zeon Corporation).
Here, the positional relationship between the partition side edge 10a in the longitudinal direction of the light reflecting film 10 and the upper edge 16b in the longitudinal direction of the partition 16 is substantially the same in the horizontal direction. Further, the width of the forward tapered inclined surface 15 b of the insulating film 15 substantially coincides with the width a of the light reflecting film 10, and is formed at a corresponding position above the light reflecting film 10.
[0008]
Furthermore, on the anode 4, the insulating film 15, and the partition 16, the organic light emitting layer 7 and the cathode 8 are sequentially laminated by vapor deposition. Here, the organic light emitting layer 7 and the cathode 8 on the partition wall 16 are separated from the organic light emitting layer 7 and the cathode 8 on the anode 4 and are electrically insulated.
[0009]
Next, the manufacturing process of the insulating film 15 and the partition 16 of the organic EL element according to the embodiment of the present invention will be described together with the operation.
When a negative photoresist material for barrier ribs applied to the entire surface to form the insulating film 15 on the anode 4 is exposed from above through a photomask, light from above through the photomask is exposed to the photoresist material. Is irradiated. Further, the irradiated light passes through the transparent anode 4 and the transparent overcoat layer 3 and is reflected by the light reflecting film 10 so that the photoresist material is also irradiated from below. Of the photoresist material, the portion irradiated with light becomes insoluble in the developing solution for resist removal processing, and the unexposed portion not irradiated with light is dissolved and removed in the developing solution. Thereby, a substantially trapezoidal insulating film 15 having a forward tapered slope 15b and a flat partition wall surface 15a is formed.
Next, the same photoresist material as that for the partition wall used for forming the insulating film 15 is applied on the insulating film 15, exposed from above through a photomask, and then processed with a developer. A reverse-tapered partition wall 16 is formed.
At this time, since the partition wall 16 is formed on the flat surface of the insulating film 15, there is little manufacturing variation in the shape of the reverse taper slope 16a of the partition wall 16, and the partition wall 16 having a certain shape can be stably formed.
Thus, since the shape of the partition 16 is constant, the metal film forming the cathode is easily divided by vapor deposition by the reverse tapered slope 16a and the sharp upper edge 16b at the top of the slope 16a. That is, since the cathode 8 is divided and electrically insulated across the partition wall 16, the cathode 8 as a plurality of electrodes patterned in stripes can be easily formed.
[0010]
In the embodiment described above, aluminum is used as the material of the light reflecting film 10, but the material is not limited to this as long as it reflects light. Silver (Ag), indium (In) Magnesium (Mg), titanium (Ti), aluminum alloy, or the like may be used.
[0011]
【The invention's effect】
According to the first aspect of the present invention, a pair of light reflecting films formed in a stripe shape along the insulating film is provided on the opposite side of the insulating film across the anode, and the insulating film is made of a negative photoresist material. Using a film , a part of the irradiation light for forming the insulating film is reflected by the pair of light reflecting films, and thus has a forward tapered slope at a corresponding position above the pair of light reflecting films. An insulating film can be formed .
According to the second aspect of the present invention , the forward tapered slope width can be formed according to the width of the light reflecting film.
According to the invention described in claim 3, since the light reflecting film is made of metal, the reflectance can be increased .
[Brief description of the drawings]
FIG. 1 is a diagram showing a structure of an organic EL element according to an embodiment of the present invention.
FIG. 2 is a diagram showing a structure of a conventional organic EL element.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 4 ... Anode, 7 ... Organic light emitting layer, 8 ... Cathode, 10 ... Light reflection film, 10a ... Partition side edge, 15 ... Insulating film, 15a ... Partition laminated surface, 15b ... Slope, 16 ... Partition, 16b ... Top Edge.

Claims (3)

On an anode extending in stripes, an organic EL element formed by sequentially stacking, a cathode an organic light-emitting layer, on a plurality of insulating films formed in a stripe shape extending in a direction orthogonal to the anode in the organic EL device in which the cathode by a partition wall which are stacked, respectively, are divided into a plurality,
On the opposite side of the insulating film across the anode, provided with a pair of light reflecting film formed in stripes along the insulation film,
The insulating film is made of a negative photoresist material,
The insulating film has a forward tapered inclined surface at a corresponding position above the pair of light reflecting films by reflecting a part of irradiation light for forming the insulating film by the light reflecting film. A characteristic organic EL element. The organic EL element according to claim 1, wherein a width of the forward tapered slope is substantially equal to a width of the light reflecting film. The light reflective film, an organic EL element according to claim 1 or 2 is made of metal.

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