JP3885303B2 - Manufacturing method of light emitting substrate - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a light-emitting display, and more particularly to a light-emitting display using an organic light-emitting material (hereinafter referred to as an organic EL material).
[0002]
[Prior art]
In recent years, liquid crystal displays have been actively used as display units for word processors, personal computers, and the like. This liquid crystal display is a non-light-emitting element, which causes a problem in terms of brightness, particularly when used in a reflective display. A light emitting display using an organic EL material having thin and light features has been attracting attention.
[0003]
A cross-sectional view of this light emitting display is shown in FIG. In the figure, 1 indicates an aluminum electrode, 2 indicates an organic EL material, 3 indicates an ITO transparent electrode, 4 indicates a glass substrate, and 5 indicates a power source.
[0004]
As can be seen from the figure, the transparent substrate is in the order of micrometers, except that a slight thickness is required, which is a very thin display.
[0005]
The manufacturing method of this light emitting display is as follows. First, an ITO transparent electrode is produced on a transparent substrate by a sputtering method or a vapor deposition method. Thereafter, an electrode having a desired shape is formed by a photolithography method or the like. Further, an organic EL material is formed on the substrate by a spin coat method, a vapor deposition method, or the like to form a light emitting layer. Further, a counter work electrode is formed by depositing a metal having a low work function, for example, magnesium, calcium, aluminum, lithium, silver, or an alloy of these metals by vapor deposition or sputtering.
[0006]
The above is the basic process. In order to increase the luminous efficiency, a hole transport layer such as N, N′-diphenyl-N, N ′-(2,4-dimethylphenyl) is further provided between the transparent electrode and the light emitting layer. ) -1,1′-biphenyl-4,4′diamine layer may be provided. Further, an electron transport layer such as a 2- (4-biphenyl) -5- (4-tert-butylphenyl) -1,3,4-oxydiazole layer may be provided between the light emitting layer and the counter electrode.
[0007]
Light can be emitted by applying an electric field between the opposing electrodes. A characteristic of this light emitting display is that it can be driven at a voltage of 10 volts or less. A light emitting display using this organic EL material is a promising technology in the future, but there is a problem when aiming at full color. That is, how to separate red, green and blue separately is a problem. . However, here, a bank that partitions the light emitting layer on the electrode is formed by the lithographic method, etc., and a solution in which red, green, and blue organic EL materials are dissolved is discharged into the bank using a discharge device, and the solvent after discharge Attention has been focused on a method of removing the material by drying to form a light emitting layer.
[0008]
[Problems to be solved by the invention]
Conventionally, the bank has been formed by photolithography. The shape was generally rectangular as shown in FIGS. Recently, a method has been proposed in which a reverse taper is applied, the bank is used as a kind of mask by using the acute angle of the bank in contact with the counter electrode, the electrode after the counter electrode deposition is cut, and the electrode is made into a strip shape. ing.
[0009]
FIG. 2 is a conceptual diagram showing a step of discharging a solution in which an organic EL material is dissolved on a substrate with a transparent electrode, which has a rectangular bank and is divided into strips, using a discharge device. FIG. 3 is a conceptual diagram showing a step of discharging a solution in which an organic EL material is dissolved by a discharge device onto a substrate having a bank on which TFT elements and ITO transparent electrodes directly connected to the elements are arranged in a matrix. FIG. 2 and 3, reference numerals 21 and 31 denote nozzles for discharging a solution in which an organic EL material is dissolved, reference numerals 22 and 32 denote organic EL materials, reference numerals 23 and 33 denote banks, reference numerals 24 and 34 denote ITO transparent electrodes, and reference numerals 25 and 35. Denotes a glass substrate, 36 denotes an insulating layer, and 37 denotes a TFT element.
[0010]
As shown in these drawings, the conventional bank has a rectangular shape or a shape in which the side in contact with the transparent electrode is shorter, that is, has a reverse taper. For this reason, there is a drawback that the area where the organic EL material is driven into the light emitting portion is reduced. For this reason, there is a drawback that it is difficult to separate red, green and blue by the discharge device.
[0011]
The present invention has been made to solve such problems, and an object of the present invention is to provide a good light emitting display that can discharge organic EL materials by a discharge device without difficulty and has no crossing between light emitting layers. It was made for that purpose.
[0012]
[Means for Solving the Problems]
In order to solve the above-described problems, a method for manufacturing a light emitting substrate according to the present invention includes a bank on which a first electrode, a light emitting layer, and a second electrode are formed in this order, and partitions the light emitting layer. A step of forming a resin mold using a metal mold having a bank whose cross section is longer than the opposite side, and a step of bringing the substrate and the resin mold into contact with each other. A glass precursor is allowed to enter and solidify into a space formed between the substrate and the resin mold, and the bank is formed on the substrate so that the side in contact with the transparent electrode side is longer than the opposite side. And a step of forming the light emitting layer in a region partitioned by the bank by discharging a solution in which an organic EL material is dissolved by an ink jet printing apparatus.
[0013]
By forming such a bank, it is possible to form a portion that receives the organic EL material that is relatively wide compared to the light emitting area. For this reason, the fluctuation margin of the ejection device is also increased.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Examples will be described in detail below.
[0015]
Example 1
Spin-coat non-photosensitive polyimide SE-812 (manufactured by Nissan Chemical Co., Ltd.) on a glass substrate with a strip-like electrode arranged with an ITO electrode width of 40 micrometers and an electrode distance of 10 micrometers under the conditions of a rotational speed of 2000 rpm and a rotational time of 20 seconds. did. This substrate was pre-baked at 80 ° C. for 30 minutes, then masked and exposed. After the exposure, etching was performed, and post-baking was performed at 160 ° C. for 30 minutes to obtain a banked substrate shown in FIG. In the figure, 41 indicates a bank, 42 indicates an ITO transparent electrode, and 43 indicates a glass substrate. A solution that dissolves red, green, and blue organic EL materials was discharged onto the substrate using a dispenser. Finally, an Mg / Ag (1:10) alloy was vapor-deposited, and an electrode was formed so as to be orthogonal to the transparent electrode, thereby forming a counter electrode.
[0016]
The light-emitting display thus obtained was matrix driven.
[0017]
(Example 2)
A silicon resin mold was prepared using a metal mold having a bank shape shown in FIG. 5 and a silicon resin (made by Toshiba Silicone). This mold is closely attached to a glass substrate on which a TFT element and an ITO transparent electrode directly connected to the TFT element are formed on a matrix, and a glass precursor (ETSB-7000, manufactured by TSB Development Center) is placed around this mold. The glass precursor was allowed to enter the space formed by the silicon resin mold and the substrate at room temperature. When the approach was completed, it was left to solidify at room temperature, and when it was solidified, the silicon resin mold was removed and baked at 200 ° C. for 2 hours to obtain a banked bank as shown in FIG. In the figure, 61 is a bank, 62 is an ITO transparent electrode, 63 is a glass substrate, 64 is an insulating layer, and 65 is a TFT element. An ink jet printing apparatus was used between the banks of the substrate to discharge a solution in which red, green, and blue organic EL materials were dissolved. Then, after drying and removing the solvent, aluminum containing 2% lithium was sputtered by a sputtering method to obtain a counter electrode.
[0018]
【The invention's effect】
As described above, the light-emitting display of the present invention can be manufactured efficiently using a discharge device and without mixing between the light-emitting layers of the respective colors.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a light-emitting display.
FIG. 2 is a conceptual diagram showing a manufacturing process of a light emitting display having strip-shaped electrodes.
FIG. 3 is a conceptual diagram showing a manufacturing process of a light-emitting display having TFT elements and ITO electrodes in a matrix.
FIG. 4 is a cross-sectional view showing the shape of a bank of a light emitting display according to the present invention.
FIG. 5 is a cross-sectional view showing a silicon resin mold formed on the bank of the light emitting display of the present invention and a mold forming the silicon resin mold.
FIG. 6 is a cross-sectional view showing the shape of a bank of a light emitting display according to the present invention.
[Explanation of symbols]
1. 1. Aluminum electrode 2. Organic EL material ITO transparent electrode 4. 4. Glass substrate Power supply 21. Nozzle 22. Organic EL material 23. Bank 24. ITO transparent electrode 25. Glass substrate 31. Nozzle 32. Organic EL material 33. Bank 34. ITO transparent electrode 35. Glass substrate 36. Insulating layer 37. TFT element 41. Bank 42. ITO transparent electrode 43. Glass substrate 51. Mold 52. Silicone resin mold 61. Bank 62. ITO transparent electrode 63. Glass substrate 64. Insulating layer 65. TFT element

Claims (1)

A method of manufacturing a light emitting substrate, wherein a first electrode, a light emitting layer, and a second electrode are formed on the substrate in this order and have a bank that partitions the light emitting layer,
Using a metal mold having a bank whose cross-sectional shape is longer than the opposite side, and forming a resin mold;
Contacting the substrate and the resin mold;
A glass precursor is allowed to enter and solidify into a space formed between the substrate and the resin mold, and the bank is formed on the substrate so that the side in contact with the transparent electrode side is longer than the opposite side. Process,
And a step of forming the light emitting layer in a region partitioned by the bank by discharging a solution in which an organic EL material is dissolved by an ink jet printing apparatus.

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