KR20140141307A - Method of manufacturing an organic light emitting device using the spin coating - Google Patents

Abstract

The present invention relates to an organic light-emitting device, and more particularly, to an organic light-emitting device including an organic light-emitting layer formed using spin coating. The feature of the present invention is to pre-coat a solvent material before forming an organic light-emitting layer. In this way, defects can be reduced by removing foreign substances generated during movement for the progress of a process, and a coating material can be uniformly coated by reducing a surface friction between a substrate and an organic material coated on the substrate or between organic and inorganic materials. Therefore, a bank having a desired line width can be formed, thereby increasing an aperture ratio and an emission luminance. In addition, the organic light-emitting layer can be formed to have a uniform thickness. Since a height difference between a central portion and an edge portion is reduced, a difference in emission amount does not occur and thus a spot removal effect can be obtained. In particular, due to the reduction in the surface friction between the substrate and the organic material coated on the substrate or between the organic and inorganic materials, the coating process can be performed with the minimum portions of both surfaces, thereby achieving the cost reduction.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method of manufacturing an organic light emitting device using spin coating,

The present invention relates to an organic light emitting device, and more particularly, to a method of manufacturing an organic light emitting device using spin coating.

BACKGROUND OF THE INVENTION [0002] Organic electro luminescent devices (OLEDs) are now self-illuminating, free of viewing angles, and energy-saving devices.

Furthermore, other advantages such as lower production cost, ease of manufacture, lower operating temperature, faster response and full coloration are possible to replace with next generation flat panel display devices.

Hereinafter, the structure of the organic light emitting device will be schematically described with reference to FIG.

The organic light emitting device 10 includes a thin film transistor array unit 14 on a transparent first substrate 12 and a first electrode 16 on the thin film transistor array unit 14, An organic light emitting layer 18, and a second electrode 20.

Here, the first electrode, the second electrode, and the organic light emitting layer form an organic light emitting diode.

In this case, the organic light emitting layer 18 displays colors of red (R), green (G) and blue (B). In general, the organic light emitting layer 18 emits red, Is used by patterning or printing.

The encapsulated organic electroluminescent device 10 is completed by bonding the first substrate 12 to the second substrate 28 on which the moisture absorbent 22 is attached through the sealant 26.

In the above-described configuration, the method of forming the organic light emitting layer 18 of the organic light emitting device may be variously attempted, for example, by spin coating.

In general, the spin coating method refers to a method of supplying a coating liquid such as a photoresist onto a substrate, and rotating a support supporting the substrate at a high speed to form a coating layer having a uniform thickness.

In order to form the organic light emitting layer 18 using a spin coating method, partition walls or banks (hereinafter, referred to as banks) defining the edges of the respective pixels should be necessarily formed. Generally, the spin coating rotates, and the organic material is applied on the plate.

At this time, the organic material may be generally dropped by a nozzle or may be applied by dropping using a blade-type nozzle.

Formation of the bank can be performed by any method such as photolithography or printing.

For example, when the photolithography method is used, an organic or inorganic material is applied according to the thickness of a bank to be formed by a predetermined method such as spray coating, and a photoresist is coated thereon.

Then, the photoresist is exposed and developed using a mask in accordance with the shape of the bank, thereby leaving the photoresist.

Finally, organic or inorganic materials other than the mask are removed by etching to form banks.

Meanwhile, in the case of this conventional method, there is no countermeasure against badness of adherence of a potential foreign substance in the process of moving to a post-process in order to progress the process for constituting an organic light emitting device, so that a defect rate .

In addition, the surface friction between the substrate and the organic material coated on the substrate increases due to the foreign matter, and the organic material is not evenly coated on the substrate, so that the organic material is coated over the reference value, thereby increasing the cost .

In addition, since the organic material does not easily spread out, the organic material applied on the central portion of the substrate may have a high thickness and a lowermost position depending on the position where the organic material is dripped (for example, The uniformity of the flatness of the organic material becomes poor.

In this way, when the bank is formed in a state in which the uniformity of the flatness is deteriorated, even if the height difference of the organic material generated at the center and the edge of the substrate is exposed and etched by the photolithographic method, .

As a result, the aperture ratio is reduced and the positional difference is generated for each pixel.

Alternatively, in the case of the organic light emitting layer, a difference in the height between the center of the substrate and the edge causes a phenomenon such as spots in the image due to the difference in the amount of light emission between regions.

FIGS. 2A and 2B are distribution diagrams showing a line width of a bank formed by a conventional spin coating method and a thickness distribution of an organic light emitting layer.

As a result of measuring the line width of the bank formed by the conventional spin coating method, the measurement range of the proclamation distribution is 35 3 m.

The line width between the first short axis and the second minor axis is 33 to 34 mu m, the line width between the second minor axis and the third minor axis is 33.5 to 34 mu m, the line width between the third minor axis and the fourth minor axis is 32.5 to 34 mu m Respectively.

The line width between the first minor axis and the second minor axis is 33 to 34.5 m, the line width between the second minor axis and the third minor axis is 34 to 34.5 m, the line width between the third minor axis and the fourth minor axis is 33 To 34.5 mu m.

The linewidth between the first short axis and the second short axis is 32.5 mm and 33 μm, the line width between the second short axis and the third minor axis is 32.5 to 33.5 μm, the line width between the third short axis and the fourth short axis is 32.5 To 33.5 mu m.

The line width between the first major axis and the third major axis is 32.5 to 33.5 mu m on the basis of the first minor axis.

And the line width between the first major axis and the third major axis is 32.5 to 34.5 m based on the second minor axis.

And the line width between the first major axis and the third major axis is 33 to 34.5 占 퐉 based on the third minor axis.

The line width between the first major axis and the third major axis is 32.5 to 34 占 퐉 based on the fourth minor axis.

Different measurements are shown for each of the major axis and minor axis, and the uniformity thereof is 2.6%, which is not uniform.

FIG. 2B is a result of an experiment in which the thickness of the organic light emitting layer formed by the conventional spin coating method is measured. The measurement range of the thickness distribution is 1.05 to 1.18 μm.

The thickness between the first minor axis and the second minor axis is 1.09 to 1.135 m, the thickness between the second minor axis and the third minor axis is 1.1075 to 1.1625 m, the thickness between the third minor axis and the fourth minor axis is 1.1075 To 1.135 m.

The thickness between the first minor axis and the second minor axis is 1.1075 to 1.19 m, the thickness between the second minor axis and the third minor axis is 1.1625 to 1.19 m, the thickness between the third minor axis and the fourth minor axis is 1.1075 To 1.19 m.

The thickness between the first minor axis and the second minor axis is 1.09 to 1.1625 m, the thickness between the second minor axis and the third minor axis is 1.135 to 1.1625 m, the thickness between the third minor axis and the fourth minor axis is 1.09 To 1.1625 m.

The thickness between the first major axis and the third major axis is 1.09 to 1.135 m based on the first minor axis.

The thickness between the first major axis and the third major axis is 1.1075 to 1.19 占 퐉 based on the second minor axis.

The thickness between the first major axis and the third major axis is from 1.135 to 1.19 占 퐉 based on the third minor axis.

The thickness between the first major axis and the third major axis is from 1.09 to 1.135 m based on the fourth minor axis.

The long axis and the short axis show different measurement values for each distinction, and the uniformity thereof is 4.3%, which is not uniform.

In order to solve the above-mentioned problems,

In forming the organic light emitting layer of the organic light emitting device OLED,

The first object of the present invention is to reduce the defect rate due to adhesion of foreign substances generated in the process of moving to a post-process for progressing a process for constituting an organic light-emitting device.

A second object of the present invention is to improve the uniformity of the line width in the formation of the banks defining the edges of the pixels.

A third object of the present invention is to reduce the frictional force between the substrate and the organic material in forming the organic light emitting layer, thereby improving the thickness uniformity.

It is also a fourth object to reduce the amount of organic material or organic and inorganic materials to be applied.

Other objects, specific advantages and novel features of the present invention will become more apparent from the following detailed description and preferred embodiments, which are to be described in connection with the accompanying drawings.

According to an aspect of the present invention, there is provided a thin film transistor comprising: a thin film transistor having a plurality of pixels defined therein, the thin film transistor being formed for each pixel; a first electrode and a second electrode connected to the thin film transistor; Forming an organic light emitting diode including an organic light emitting layer between the electrodes, the method comprising: forming a solvent layer by spin coating a solvent material on a surface of the substrate on which the thin film transistor and the first electrode are formed; And forming a polymer layer on the solvent layer by spin coating. The present invention also provides an organic light emitting device using the spin coating method.

The polymer layer is patterned to form a bank so as to divide and define the plurality of pixels.

The polymer material layer is applied to each of the plurality of pixels to form an organic light emitting layer of red, green, and blue.

The polymer material layer is coated on the substrate, and the solvent layer is removed or dissolved together with the foreign substance remaining on the substrate.

The solvent material may be any of materials such as propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monomethyl ether (PGME), and n-propyl acetate acetate (n-PAC) And is made of one material.

According to the "method for manufacturing an organic light emitting device using spin coating" according to the present invention, the particles generated during the movement process are chemically and physically removed by a prior solvent coating And has an effect of reducing defects.

In addition, since the surface friction between the organic material or the organic and inorganic material applied on the substrate and the substrate is reduced by the solvent coating, the coating material can be uniformly applied and the bank having the desired line width can be formed, The aperture ratio is reduced, or the emission luminance is lowered.

In addition, since the surface friction between the organic material or the organic and inorganic materials applied on the substrate and the substrate is reduced by the solvent coating, the organic material can be uniformly applied and the organic light emitting layer can be formed with a uniform thickness, And the height difference between the edges is small, the difference in the amount of light emission does not occur and the effect of removing stains is obtained.

In addition, since the surface friction between the substrate and the organic material or the organic and inorganic materials applied on the substrate is reduced, the coating process can be performed with a minimal amount, thereby reducing the cost.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a schematic view showing the structure of an organic light emitting diode according to a conventional technique. FIG.
FIGS. 2A and 2B are distribution diagrams showing a line width of a bank formed by spin coating and a thickness distribution of an organic light emitting layer according to a related art.
3A to 3D are process flow diagrams illustrating a process of removing particles on a surface of a substrate according to the present invention by solvent coating.
4A to 4E are process flow diagrams illustrating a bank formation process for separating an organic light emitting layer from a substrate to which a solvent coating according to the present invention is applied.
5A to 5E are schematic views showing a spin coating method of an organic light emitting layer according to the present invention.
6A to 6C are experimental results showing the line width of the bank and the thickness of the organic thin film according to the present invention.

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

The embodiments described below are provided to illustrate the technical concept of the present invention, and the technical scope of the present invention is not limited to the following embodiments.

3A to 3D are process flow diagrams illustrating a process of removing particles on a surface of a substrate by applying solvent coating according to the present invention.

A spindle 100, a spin chuck 110, a first substrate 120, a nozzle 80, and a nozzle 80 on the first substrate 120 as shown in FIG. And a solvent material 82, which will be briefly described.

The foreign substance 90 remains on the first substrate 120. The foreign substance 90 may be composed of solid particles, organic contaminants, inorganic contaminants and the like and may be formed in the form of an organic contaminant film on the first substrate 120 Or may be formed in the form attached to dust particles.

Subsequently, the first substrate 120 schematically shows an active matrix type organic light emitting diode. Pixels are defined on a transparent insulating substrate such as plastic or glass, and an active layer, a gate electrode, a source electrode and a drain And a thin film transistor composed of an electrode is formed.

The thin film transistor is formed by depositing and patterning a selected one of transparent organic insulating materials including benzocyclobutene (BCB) and acrylic resin to form a protective film exposing a part of the drain electrode, And an anode electrode to be contacted is formed independently for each pixel.

As an anode electrode, a metal having a high work function is used, and indium-tin-oxide (ITO) which is a transparent electrode is exemplified.

The spin chuck 110 having a shape coupled to the spindle 100 schematically shows a typical spin coater equipment in a process of applying a polymer in an organic thin film process, and its general features are omitted.

3A, the first substrate 120 to which the foreign object 90 is attached is brought into a spin coater equipment (not shown), and the first substrate 120 is placed on the spin chuck 110 And is adsorbed on the spin chuck 110 by a vacuum hole (not shown).

Then, the solvent material 82 is dropped onto the first substrate 120 through the nozzle 80 in a spin coater equipment (not shown).

As shown in FIGS. 3B to 3C, the spindle 100 is rotated by sealing the spin coater equipment (not shown) from the outside and driving a motor (not shown).

At this time, the operation of the motor (not shown) located under the spin chuck 110 is 1200 [RPM].

The spin chuck 110 having a shape coupled with the spindle 100 and the first substrate 120 attracted to the spin chuck 110 are also rotated as the spindle 100 rotates, The solvent material 82 dripped on the top surface of the substrate is spread evenly on the upper surface by the centrifugal force.

At this time, the foreign object 90 is dissolved by the solvent material 82 or is separated from the upper portion of the first substrate 120 by the centrifugal force.

3D, the solvent material 82 is applied to the entire surface of the first substrate 120 by the rotation of the spin chuck 110 and the first substrate 120 to form the solvent layer 123 .

That is, the process of coating the solvent material (82 in FIG. 3C) on the spin chuck 110 having a shape coupled with the spindle 100 and the first substrate 120 adsorbed on the spin chuck 110 can be performed by a process There is an advantage in that the residual water on the substrate which is generated during the movement of the liver removes the water 90 to reduce the defective rate.

The above-mentioned solvent material (82 in FIG. 3C) is a mixture of propylene glycol monomethyl ether acetate (PGMEA), propylene glycol ether ether (PGME), n-propyl ether acetate Propyl acetate or the like.

Further, the thickness of the coated solvent layer 123 is preferably 50 to 100 ANGSTROM, but it is a thickness before drying and will be described later in detail after the drying process.

Hereinafter, a process of forming the banks 130a and 130b, which define the edges of each pixel on the first substrate 120 coated with the solvent layer 123, will be briefly described.

4A to 4E are flowcharts illustrating a process of forming a bank for separating an organic light emitting layer from a substrate to which a solvent coating according to the present invention is applied

A polymer material 84 such as polyimide is applied to the first substrate 120 through the nozzle 80 while the solvent layer 123 is coated on the first substrate 120 as shown in FIG. To the top.

4B to 4C, the first substrate 120 on which the polymer material 84 is dropped is rotated by using a motor (not shown), so that the polymer material 84 is transferred to the first substrate 120 .

At this time, the surface friction between the solvent layer 123 formed on the first substrate 120 and the dropped polymer material 84 decreases, so that the polymer material 84 can be uniformly spread on the first substrate 120 And the solvent layer 123 previously applied while rotating is absorbed or dissolved in the polymer material 84 as the polymer material 84 spreads over the entire surface of the first substrate 120.

Therefore, when the polymeric material 84 is uniformly applied on the first substrate 120, the solvent layer 123 is completely absorbed into the polymeric material layer 130 and disappears.

The thickness of the polymer material layer 130 is 5 to 50 μm, and the amount of rotation of the motor (not shown) is 1000 [RPM].

Thereafter, the coated polymeric material layer 130 is heated to dry on the first substrate 120 through equipment such as an electric heater. At this time, the temperature to be heated through the electric heater is 110 to 130 占 폚.

Hereinafter, the process of forming the polymer material layer 130 of the first substrate 120 on the banks 130a and 130b (see FIG. 4d) will be described in detail.

4D to 4E, in the exposure method using negative photoresist, a polymer material layer 130 is coated on the first substrate 120, a negative photoresist layer 130 is formed on the polymer material layer 130, (135a).

The mask 140 is mounted on the negative photoresist layer 135a at an appropriate interval and then exposed to ultraviolet light (UV).

At this time, the exposure dose is preferably 50 to 100 mJ, but it should not be limited thereto.

The mask 140 is largely divided into a transparent first portion for completely passing light therethrough, and a second portion for completely blocking light.

The first portion is exposed so that the photoresist layer 135a is completely left open, and the second portion is completely covered since the negative photoresist layer 135a should be absent.

After the negative photoresist layer 135a is developed, the negative photoresist layer 135a is completely left in the first portion of the first portion, the negative photoresist layer 135a is completely removed in the second portion, (130) is directly exposed.

When the etching is performed after development of the negative photoresist layer 135a, the bank layer 130 is etched in the second portion while the negative photoresist layer 135a is etched in the first portion. As a result, the formation of the bank 130a is performed.

Next, the process of forming the organic light emitting layer 150 on the first substrate 120 on which the banks 130c are formed will be described in detail with reference to FIGS. 5A to 5E.

5A, the first substrate 120 is attracted to an upper portion of a spin chuck 110 having a shape coupled to the spindle 100, and the edge of each pixel is disposed on the first substrate 120 A bank 130a is formed which is divided and defined.

5B, a solvent material 82 is dropped onto the first substrate 120 through the nozzle 80 and the motor (not shown) is rotated at a speed of 1200 RPM to remove the solvent material 82, Is uniformly applied between the upper bank 130a of the first substrate 120 and the upper bank 130a.

5C, the solvent material 82 is uniformly applied between the banks 130a on the first substrate 120 to form the solvent layer 123. In this case,

At this time, the thickness of the solvent layer 123 is preferably 50 to 100 Å.

5D, when the solvent layer 123 is formed on the first substrate 120, the polymer organic material 86 is dropped using the nozzle 80. As shown in FIG.

At this time, the surface friction between the solvent layer 123 formed on the first substrate 120 and the dropped polymer material 84 decreases, so that the polymer material 84 can be uniformly spread on the first substrate 120 do.

In this state, the motor (not shown) is rotated at a speed of 800 [RPM] to uniformly coat the first substrate 120.

As shown in FIG. 5E, an organic light emitting layer 150 is formed.

In this case, the solvent layer (123 in FIG. 5D) absorbs the polymer organic material (86 in FIG. 5D) as much as the polymer organic material (86 in FIG. 5D) Or melted, so that only the organic light emitting layer 150 is applied to the first substrate 120.

At this time, the organic light emitting layer 150 has a thickness of 0.5 to 2 μm before being dried.

Then, the organic light emitting layer 150 is heated to be dried through equipment such as an electric heater.

At this time, the temperature to be heated through the electric heater is 150 to 220 ° C.

The thickness of the cured organic light emitting layer 150 after drying is 200 to 1000 ANGSTROM.

The organic light emitting layer 150 may be formed of a single organic light emitting layer,

(HIL), an emission layer (EIL), an electron transport layer (ETL), an electron injection layer (EIL), and a hole transport layer Layer) may be further formed.

The precursor transport layer may include amines including, but not limited to, aromatic tertiary amines including a porphyrin transport layer. One form of the aromatic tertiary amine is an arylamine such as, but not limited to, monoarylamine, diarylamine, triarylamine, or polymericarylamine. Lt; / RTI > In addition, polymeric hole transport materials include poly (N-vinylcarbazole), polythiophenes, polypyrrole, polyaniline, poly (3,4-ethylenedioxythiophene) 4-styrenesulfonate)).

The organic light emitting layer 150 may include dyes or coumarins, and may be a polymeric material in a natural state.

Polymeric materials such as polyfluorenes and polyvinylarylenes (e.g., poly (p-phenylenevinylene)) (PPV) may also be used as the host material.

The electron transporting material may include any material known to be useful for this purpose to those skilled in the art. Such compounds aid in the injection and transport of electrons, exhibit high levels of performance, and are readily prepared in the form of thin films. For example, metal chelated oxinoid compounds (including 8-quinolinol or 8-hydroxyquinoline), including, but not limited to, the chelates of oxine itself, (Also called 8-hydroxyquinoline) can be used.

As described above, a cathode electrode is formed on the entire surface of the substrate on which the organic light emitting layer is formed to complete the organic light emitting diode including the anode electrode, the organic light emitting layer, and the cathode electrode.

6A to 6C, measurement results of the line width of the bank and the thickness of the organic light emitting layer in the spin coating using the solvent material according to the present invention will be described in detail.

FIG. 6A is a result of measuring the line width of the bank formed according to the present invention, and the measurement range of the proclamation distribution is 35. + -. 3 .mu.m.

A line width between the first minor axis and the second minor axis is 33 to 34 μm, a line width between the second minor axis and the third minor axis is 33.5 to 34.5 μm, a line width between the third minor axis and the fourth minor axis is 33.5 to 33.5 μm, Respectively.

The line width between the first minor axis and the second minor axis is 33.5 to 34.5 m, the line width between the second minor axis and the third minor axis is 34 to 34.5 m, the line width between the third minor axis and the fourth minor axis is 34 To 34.5 mu m.

The line width between the first short axis and the second minor axis is 33 to 33.5 μm, the line width between the second minor axis and the third minor axis is 33 to 34 μm, the line width between the third minor axis and the fourth minor axis is 33 To 34 m.

The line width between the first major axis and the third major axis is 33 to 34 占 퐉 based on the first minor axis.

And the line width between the first major axis and the third major axis is 33 to 34.5 占 퐉 based on the second minor axis.

And the line width between the first major axis and the third major axis is 33.5 to 34.5 m based on the third minor axis.

The line width between the first major axis and the third major axis is 33 to 34.5 占 퐉 based on the fourth minor axis.

That is, there is a small difference value measurement in each of the long axis and short axis regions, and the uniformity thereof is 1.4%, which can be interpreted to be uniformly applied with almost no step difference compared to the uniformity of 2.6% measured in FIG.

FIG. 6B shows a result of measuring the thickness of the organic light emitting layer formed according to the present invention, and the measurement range of the thickness distribution is 1.05 to 1.18 μm.

The thickness between the first minor axis and the second minor axis is 1.09 to 1.135 m, the thickness between the second minor axis and the third minor axis is 1.1075 to 1.135 m, the thickness between the third minor axis and the fourth minor axis is 1.09 To 1.135 m.

The thickness between the first minor axis and the second minor axis is 1.1075 to 1.1625 m, the thickness between the second minor axis and the third minor axis is 1.1075 to 1.1625 m, the thickness between the third minor axis and the fourth minor axis is 1.1075 To 1.135 m.

The thickness between the first minor axis and the second minor axis is 1.09 to 1.1135 占 퐉, the thickness between the second minor axis and the third minor axis is 1.1075 to 1.135 占 퐉, the thickness between the third minor axis and the fourth minor axis is 1.09 To 1.1135 m.

The thickness between the first major axis and the third major axis is 1.09 to 1.135 m based on the first minor axis.

The thickness between the first major axis and the third major axis is 1.1075 to 1.625 占 퐉 based on the second minor axis.

The thickness between the first major axis and the third major axis is from 1.1076 to 1.135 m based on the third minor axis.

The thickness between the first major axis and the third major axis is from 1.09 to 1.135 m based on the fourth minor axis.

That is, it can be interpreted that the uniformity of the long axis and the short axis is small and the uniformity of the uniformity is 2.3%, which is uniform compared with the uniformity of 4.3% measured in 2b.

6C is a cross-sectional view of another embodiment including the results of the invention of FIGS. 6A-6B.

Sample 1 is another embodiment of the present invention in which a polymer such as a polyimide is dropped without taking countermeasures against foreign substances generated in the process of moving for the process of constructing the organic light emitting device, A bank in which the edges are divided and formed, and a polymer organic material is dropped to form an organic light emitting layer.

The thickness of the center part of the organic luminescent layer of Sample 1 was 1.16 μm and the thickness of the edge was 1.11 μm, and the polymer organic material did not spread well from the center.

In addition, the line width of the bank was 33.7 mu m at the center portion, and the polymer such as polyimide dripped at the edge line width of 32.7 mu m did not spread well from the center portion.

Sample 3 is also briefly described as another embodiment.

In order to proceed with the process for constructing the conventional organic light emitting device as described above, a polymer such as polyimide is directly dropped without dropping a solvent material that does not have countermeasures due to adhesion of foreign substances generated in the process of moving, , A solvent material and a polymer material are simultaneously applied to form a bank defining the edge of each pixel.

The formation of the organic luminescent layer is the same as that of Sample 1.

The thickness of the center part of the organic light emitting layer of Sample 2 was 1.22 μm and the thickness of the edge was 1.11 μm, and the polymer organic material did not spread well from the center.

In addition, the line width of the bank was 34.1 mu m at the center, and the polymer such as polyimide dripped at the edge line width of 33.1 mu m did not spread well from the center.

Finally, Sample 2 is a cross-sectional view showing the distribution diagrams shown in Figs. 6A to 6B.

The thickness of the center part of the organic light emitting layer is 1.11 mu m and the thickness of the edge is 1.08 mu m, which shows a large difference from the results of Sample 1 to Sample 2.

This means that there is almost no difference in height between the center and the edge.

The line width of the bank is 33.4 μm at the center and 33.5 μm at the edge.

This implies that the difference in height between the center and the edge is practically applied.

Table 1 below shows the relationship between line width and thickness when solvent coating is not performed and solvent coating is not performed.

Coating conditions Frictional force with the substrate Remarks Sample 3 0.72 0.2 <no correlation,
0.2 ~ 0.4 Low correlation
0.4 to 0.7 Relatively high relationship,
0.7 ~ 0.9 High correlation
0.9> very high relationship Sample 1 0.765 Sample 2 0.609

As shown in the figure, it can be seen that the frictional force between the substrate and the polymer material is lowered in the substrate coated with the solvent material. The lower the correlation, the better the uniformity.

In the present invention, in the formation of the bank defining the edge of each pixel by using spin coating and the step of forming the organic light emitting layer,

Particles generated in the upper part of the substrate during the movement between processes are chemically and physically cleaned by coating a pre-solvent material on the substrate, thereby reducing the defective rate.

In addition, since the surface friction of the substrate is reduced by the solvent coating, the coating material can be uniformly applied, and the line width of the bank that can be formed is reduced, thereby improving the aperture ratio and increasing the light emission luminance.

In addition, since the thickness of the light emitting layer becomes uniform, the step difference between the center portion and the edge is reduced, and the difference in the height of the edge is reduced, so that there is no difference in the amount of light emission, and no unevenness is caused.

In addition, the coating process can be performed with a minimal amount of reduction in surface frictional force, thereby reducing the cost.

As a result, the defect rate is reduced and the process capability is improved.

As described above, those skilled in the art will understand that the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof.

It is therefore to be understood that the above-described embodiments are to be considered in all respects as illustrative and not restrictive. The scope of the present invention is defined by the appended claims rather than the detailed description and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included within the scope of the present invention.

100: spindle 110: spin chuck
120: first substrate 130a: bank
150: organic light emitting layer

Claims (5)

An organic light emitting diode including an organic light emitting layer between the first electrode and the second electrode is formed, and a plurality of pixels are defined, and a thin film transistor formed for each pixel, a first electrode and a second electrode connected to the thin film transistor, The method comprising the steps of:
Forming a solvent layer by spin-coating a solvent material on a surface of the substrate on which the thin film transistor and the first electrode are formed;
Forming a polymer layer on the solvent layer by spin coating;
Wherein the spin coating is performed using a spin coating method.
The method according to claim 1,
Wherein the polymer layer is patterned so as to divide and define the plurality of pixels, thereby forming a bank.
The method according to claim 1,
Wherein the polymer material layer is applied to each of the plurality of pixels to form an organic light emitting layer of red, green, and blue, respectively.
The method according to claim 1,
Wherein the polymer layer is coated on the substrate, and the solvent layer is removed or dissolved together with the foreign substance remaining on the substrate.
The method of claim 1,
The solvent material may be any of materials such as propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monomethyl ether (PGME), and n-propyl acetate acetate (n-PAC) Wherein the organic layer is formed of a single material.

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