KR20150089356A - Method of manufacturing for organic electro luminescence device and organic electro luminescence device - Google Patents

Abstract

The present invention is to improve the extraction efficiency of light emitted to the outside by reducing light which is absorbed to disappear in the interface of the organic electro luminescence device of the present invention. A method of manufacturing an organic electro luminescence device (10) includes forming a polymer layer (12) by coating polymer on a substrate (10), forming a recess layer (13) having recess parts by applying an ion impact stress caused by plasma to the polymer layer (12), successively forming a first electrode, an organic light emitting layer and a second electrode on the opposite side of the recess layer forming surface of the substrate (11) having the recess layer (13). Also, it further includes forming a metal layer (23) in the upper part of the polymer layer. A metal layer (23) may be removed after the recess is formed by applying an ion impact stress and a thermal stress at the same time.

Description

Technical Field [0001] The present invention relates to a method of manufacturing an organic electroluminescent device and an organic electroluminescent device using the organic electroluminescent device,

The present invention relates to a method of manufacturing an organic electroluminescent device and an organic electroluminescent device.

An organic electroluminescent device (hereinafter simply referred to as " organic light emitting device ") has a structure in which an organic light emitting layer containing an organic compound is inserted between a pair of electrodes formed of a positive electrode and a negative electrode formed on a transparent substrate such as glass Holes and electrons are injected into the organic light emitting layer from the pair of electrodes to recombine the excitons to emit excitons to emit light when the excitons are lost in activity, Emitting device.

An organic light emitting display device using this organic light emitting element as a light emitting element has been attracting attention as a flat panel display device because it is lightweight and thin and has excellent luminance characteristics and viewing angle characteristics compared with other display devices. have.

When the organic light emitting device is used for a display device, a light source for illumination, etc., it is desirable to extract as much light as possible from the organic light emitting layer in the organic light emitting device to the outside of the device from the viewpoint of utilization efficiency and power consumption, It is known that only about 20% of the light generated in the organic light emitting layer is drawn out by the organic light emitting layer. The major causes of this are absorption and extinction in the organic material itself, Or due to the absorption loss or extinction of light due to the so-called plasmonic resonance. The other reason is that the total reflection due to the difference in refractive index between the electrode and the substrate deteriorates the light extraction efficiency .

Therefore, it is one of the important problems in the field of organic light emitting devices that light is extracted to the outside of the device by improving the light extraction efficiency of low efficiency as described above.

Techniques of Patent Documents 1 and 2 have been proposed as prior arts for improving the light extraction efficiency. The technology of these documents is that the scattering layer is formed on the outer surface of the substrate or the organic light emitting layer, So that the light extraction efficiency is improved by the scattering action of the light generated in the light source.

However, in Patent Documents 1 and 2, since a scattering layer is formed by dispersing scattering particles in a solvent and inserting a coating between the transparent electrode and the substrate, there is a problem that it is difficult to mass-produce the scattering layer because it is impossible to complete dispersion.

Another conventional technique for improving the light extraction efficiency is disclosed in Patent Document 3. FIG. 1 is a schematic cross-sectional view of an organic light emitting device of Patent Document 3. FIG.

As shown in Fig. 1, the organic light emitting device of Patent Document 3 includes a polymer 70 on a substrate 50, a first electrode 61 made of ITO or the like, an organic layer 62, and a second Electrodes 63 are sequentially arranged on the polymer 70 and irregularities 71 having a shape such as a circle, an ellipse, and a hemisphere are formed on the polymer 70.

The method of forming the concavities and convexities 71 is a method in which a hydroxyl group is formed on the substrate 50 by an oxygen plasma treatment and then the polymer 70 is coated on the substrate 50 to form microparticles After the coated mold is imprinted, it is UV-cured in a nitrogen atmosphere to form irregularities 71. Next, the organic light emitting device is manufactured by sequentially forming the first electrode 61, the organic light emitting layer 62, and the second electrode 63 in a known manner.

As described above, in Patent Document 3, although the unevenness is formed by so-called nano-imprinting, the nanoimprinting method has a problem in that mass production is difficult because the process is complicated and the process cost is high. In addition, since the polymer is vulnerable to moisture, a separate countermeasure is required to solve the problem of moisture penetration into the device.

As another method for improving the light extraction efficiency, a method of adhering an MLA film (Micro Lens Array Film) to the substrate surface of an organic light emitting element, a method of changing the roughness of the substrate surface by using a sand blast method And so on.

However, in the method of bonding the MLA film, there is a loss of photons extracted to the outside due to the difference in optical characteristics (refractive index, absorptivity) between the adhesive film and the MLA film, and expensive equipment is required for film adhesion, And there is a problem that there is a great concern about inflow of bubbles generated in the film bonding process, and the sandblast method also has a problem that it is difficult to obtain a certain surface roughness.

On the other hand, as a method for improving the problem of the conventional method, there is a technique of Patent Document 4 filed by the present applicant and undisclosed.

The technique of Patent Document 4 is a technique of applying ion shock stress by plasma or simultaneously applying ion shock stress and heat stress to a polymer layer coated on a substrate or a polymer layer and a metal layer which are sequentially laminated on a substrate, And a first electrode, an organic light emitting layer, and a second electrode are sequentially formed on the uneven layer on the substrate to produce an organic electroluminescent device.

Patent Document 1: WO 02/37580 A1 public pamphlet (disclosed on May 10, 2002) Patent Document 2: US 2001 / 0026124A1 publication (published on October 4, 2011) Patent Document 3: Published Patent Application No. 10-2011-87433 (Published on August 3, 2011) Patent Document 4: Patent Application 10-2013-0145508 (Patent Application pending on November 27, 2013)

In Patent Document 4, only a method of sequentially forming the first electrode, the organic light emitting layer and the second electrode on the uneven layer formed on the substrate has been proposed. However, according to the repeated studies of the present inventors, That is, on the side of the light extraction surface, and it has been confirmed by this method that the light extraction efficiency equal to or better than that of the method of Patent Document 4 can be obtained.

The present invention has been made in view of the above findings and provides a method of manufacturing an organic electroluminescent device which can improve the light extraction efficiency of an organic light emitting device by a relatively simple process and reduce the manufacturing cost of the device, And an object of the present invention is to provide an organic electroluminescent device manufactured thereby.

According to another aspect of the present invention, there is provided a method of manufacturing an organic electroluminescent device, comprising: forming a polymer layer on a substrate; Forming an uneven layer on the polymer layer; forming a first electrode on a surface opposite to the uneven layer formation surface of the substrate; forming an organic light emitting layer on the first electrode; And forming a second electrode on the light emitting layer.

According to another aspect of the present invention, there is provided a method of manufacturing an organic electroluminescent device, comprising the steps of: forming a polymer layer on a substrate; forming a metal layer on the polymer layer; Forming a first electrode on a surface of the substrate opposite to the surface on which the concavoconvex layer is formed, and forming a second electrode on the surface of the substrate opposite to the concavoconvex layer; Forming an organic light emitting layer on the first electrode, and forming a second electrode on the organic light emitting layer.

The organic electroluminescent device of the present invention includes a substrate, a first electrode formed on the substrate, an organic light emitting layer formed on the first electrode, and a second electrode formed on the organic light emitting layer, The substrate has a plurality of uneven layers formed on the opposite surface of the first electrode, and the uneven layer is a layer formed by applying ion impact stress to the polymer layer formed on the substrate.

According to another aspect of the present invention, an organic electroluminescent device includes a substrate, a first electrode formed on the substrate, an organic light emitting layer formed on the first electrode, and a second electrode formed on the organic light emitting layer Wherein the substrate has a plurality of uneven layers formed on a surface opposite to the first electrode, the uneven layer is a layer formed by applying ion shock stress to a polymer layer and a metal layer sequentially formed on the substrate, The metal layer is removed after impact stress.

According to the organic light emitting device of the present invention, a plurality of irregularities having irregularities are formed by applying ionic shock stress to a polymer layer laminated on a substrate, and a plurality of irregularities are formed on the opposite side of the irregular layer, Since the electrode, the organic light emitting layer, the second electrode, and the like are formed, the amount of light that absorbs and extinguishes in the organic light emitting element can be reduced by the uneven layer, and the extraction efficiency of light extracted to the outside can be improved. It is possible to reduce power consumption.

In addition, compared to the conventional method, the step of forming the uneven layer is simple, no additional equipment is required for forming the unevenness layer, and since it can be formed by using the existing organic light emitting device manufacturing equipment, mass production Can be obtained.

1 is a cross-sectional view showing a schematic structure of a conventional organic light emitting device,
2 is a view showing a manufacturing process of the organic light emitting device according to the first embodiment of the present invention,
Fig. 3 (a) is a cross-sectional view of the organic light-emitting device manufactured by the first embodiment, Fig. 3 (b)
4 is a view showing a manufacturing process of an organic light emitting device according to a second embodiment of the present invention,
5 is a graph showing the distribution of light of an organic light emitting device fabricated by a conventional method and an organic light emitting device fabricated by the method of the present invention,
FIG. 6 is a graph showing voltage-current density characteristics of an organic light emitting device fabricated by a conventional method and an organic light emitting device fabricated by the method of the present invention,
FIG. 7 is a graph showing the voltage-power efficiency of the organic light emitting device fabricated by the conventional method and the organic light emitting device fabricated by the method of the present invention,
8 is a graph showing the emission spectrum of the organic light emitting device fabricated by the conventional method and the organic light emitting device fabricated by the method of the present invention.

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

≪ Embodiment 1 >

First, a preferred embodiment 1 of the present invention will be described with reference to Figs. 2 and 3. Fig. FIG. 3 is a cross-sectional view of the organic light-emitting device manufactured according to the first embodiment, and FIG. 3 (b) is an optical microphotograph of the unevenness .

As shown in Fig. 2, first, a substrate 11 is prepared (Fig. 2 (a)). The substrate 11 is a substrate used in a conventional organic light emitting element 10, and for example, transparent glass or a transparent plastic substrate can be used.

Subsequently, the substrate 11 is cleaned. The substrate 11 may be cleaned by a known method such as using a cleaning agent and an ultrasonic cleaning equipment, and the cleaned substrate 11 is dried through a drying process.

Next, the polymer is coated on the cleaned and dried substrate to form the polymer layer 12 (Fig. 2 (b)).

As the polymer for forming the polymer layer 12, a material satisfying the following conditions is suitable.

1. Stable against etchant, developer, stripper, etc., and free from chemical damage.

2. Heat treatment at 300 ℃ or more should not cause thermal damage.

3. There should be no out-gassing.

4. Coating process with a thickness of 1 μm or less should be possible.

5. There must be reproducibility of the stress during the formation of the polymer layer (12).

6. Photolithography process must be possible.

7. It should have an appropriate optical coefficient such as a refractive index of 1.5 or more, a low light absorptance (low extinction coefficient), and a transmittance of 90% or more.

In this embodiment, a touch screen over coating material SOI-4000 manufactured by SAMYANG EMS CORPORATION was used as the material of the polymer layer 12.

In this embodiment, the spin coating method is used, the coating speed is in the range of 500 to 2000 RPM, and the coating thickness of the polymer layer 12 is 0.3 to 3.0 탆. However, the coating method is not limited to spin coating, and other methods may be used as long as the polymer layer 12 can be formed by coating a predetermined thickness of polymer on the substrate 11. [

Then, soft bake is performed at a temperature of 100 캜 for about 90 seconds, and then an ion bombardment stress is applied to the surface of the polymer layer 12 to form a plurality of (Unevenness) is generated to form the uneven layer 13 (Fig. 2 (c)).

The uneven layer 13 is formed by introducing the substrate 11 on which the polymer layer 12 is formed into the plasma processing apparatus and performing plasma treatment. In the present embodiment, argon is used as the used gas, 200SCCM, pressure of 8Pa, power of 50 ~ 200W, and the treatment time was in the range of 1 ~ 20 minutes.

Subsequently, a substrate on which the uneven layer 13 is formed is obtained through a curing process which starts at a temperature of about 230 ° C and gradually cures for about 2 to 6 hours while lowering the temperature to room temperature.

3B is a photograph of an electron microscope (Olympus Confocal Laser Scanning Microscope LEXT OLS3000) of a concavo-convex layer 13 formed on a substrate 11, and a large number of irregularities are relatively regularly formed on the substrate 11 can confirm.

The thickness of the polymer layer 12, the period of irregularities of the formed uneven layer 13, and the height of the irregularities are shown in Table 1 according to the coating speed.

Coating Speed (RPM) Coating Thickness (탆) The average period (占 퐉) Average height of unevenness (占 퐉) Sample 1 500 3.0 7.0 0.60 Sample 2 1000 1.5 4.9 0.86 Sample 3 1500 0.9 3.5 0.18 Sample 4 2000 0.3 2.6 0.11

It can be seen from Table 1 that the coating thickness of the polymer layer 12, the average period and average height of the concavities and convexities of the concavo-convex layer 13 are directly related to the coating speed by spin coating, It is possible to set the thickness of the coating of the polymer layer 12 suitable for the characteristics of the device such as the use, size and material of the substrate 10, thereby setting the period and height of the uneven layer 13 appropriately as required Able to know.

In the present embodiment, the size of the irregularities is preferably 300 nm to 200 μm, and the effect of the present invention is insignificant when the size of the irregularities is less than 300 nm or exceeds 200 μm.

Also, depending on the shape of the concavities and convexities, the light extraction efficiency is affected. That is, the light extraction efficiency can be improved when the shape of the irregularities is an elliptical shape or an irregular shape as compared with a case where the irregular shape is a complete sphere shape.

In the present embodiment, the surface of the polymer layer 12 is treated with argon plasma by a method of applying stress caused by ion impact, but the present invention is not limited thereto, and the polymer layer 12 may be formed by another suitable method. The stress caused by the ion impact may be applied to the surface of the semiconductor substrate 10 to form the uneven layer 13.

3 (a), a first electrode 14 is formed on the opposite surface of the substrate 11 on which the uneven layer 13 is formed on one surface thereof, and a surface of the substrate 11 opposite to the surface on which the uneven layer 13 is formed. The layer 15 and the second electrode 16 are sequentially formed and if necessary a getter 17 or the like is further formed and then sealed with a cover glass 18 to complete the organic light emitting element 10. [

If the first electrode is a cathode, the second electrode is a cathode, and if the first electrode is a cathode, the second electrode is an anode, and is determined according to whether the organic light emitting device of the present invention is a front emission type or a back light emission type. However, the side of the substrate 11 on which the concave-convex layer 13 is formed becomes a light-extracting surface from which light is extracted.

The method of forming the first electrode, the organic light emitting layer, the second electrode, etc., materials, conditions, and the like can be selectively used in a variety of known methods, and thus are not described herein.

As described above, according to the organic luminescent element 10 of the present embodiment, the irregular layer 13 having many irregularities is formed by applying the ion impact stress to the polymer layer 12 laminated on the substrate 11 The organic light emitting layer 15 and the second electrode 16 are sequentially formed on the surface of the substrate 11 on which the concavo-convex layer 13 is formed, It is possible to improve the light extraction efficiency to be drawn out to the outside of the organic light emitting element 10 by the uneven layer 13, thereby saving power consumption at the same luminance.

In addition, compared to the conventional method, the step of forming the uneven layer 13 is simple, and no additional equipment is required for forming the uneven layer 13, and it can be formed by using the existing organic light emitting device manufacturing equipment It is possible to mass-produce at low cost.

≪ Embodiment 2 >

Next, a second preferred embodiment 2 of the present invention will be described in detail with reference to Fig. 4 is a view showing a manufacturing process of the organic light emitting device according to the second embodiment of the present invention.

Embodiment 2 differs from Embodiment 1 in the step of forming a roughened layer, and the other steps are the same, and therefore, differences from Embodiment 1 will be mainly described below.

First, a polymer layer 22 is formed by coating a polymer on a transparent substrate 21 such as glass or plastic (Figs. 4 (a) and 4 (b)). The material of the substrate 21 and the method of forming the polymer layer 22 are the same as those of the material of the substrate 11 and the method of forming the polymer layer 12 in the first embodiment.

It is preferable to perform an EBR (Edge Bead Remove) process for removing the beads adhered on the substrate 21 in the process of forming the polymer layer 22 on the substrate 21 on which the polymer layer 22 is formed, The EBR process is performed by a known method.

Then, a metal layer 23 is deposited on the polymer layer 22 (Fig. 4 (c)). The metal layer 23 is deposited by a conventional metal layer deposition method such as ion beam deposition. In this embodiment, the metal layer 23 is deposited to a total thickness of 10 nm at a rate of 0.1 nm per second.

As the material for forming the metal layer 23, for example, aluminum (Al) can be used, and aluminum has a large difference in thermal expansion coefficient from the polymer layer 22, so that the sacrificial uneven layer 25 can be easily formed have. However, the material for forming the metal layer 23 is not limited to aluminum, and other metals may be used.

Subsequently, ion shock stress is applied to the substrate on which the polymer layer 22 and the metal layer 23 are formed to form a concave-convex layer 24 and a sacrificial concavo-convex layer 24 on the upper part of the polymer layer 22 and the upper part of the metal layer 23, respectively 25 (see Fig. 4 (d)). The method and conditions for applying the ion impact stress to the substrate on which the polymer layer 22 and the metal layer 23 are formed are the same as those in the uneven layer 13 in the first embodiment.

Thermal stress is then applied to the substrate on which the polymer layer 22 and the metal layer 23 are formed after application of the ion bombardment stress. The thermal stress is applied either directly to the substrate on which the polymer layer 22 and the metal layer 23 are formed or after the substrate subjected to the ion impact stress is introduced into the heating furnace, To about 2 hours.

The application of the ion bombardment stress and the application of the thermal stress may be performed simultaneously in the same process or may be performed by first applying the thermal stress after the ion bombardment stress is applied. In this embodiment, the polymer layer 22 and the metal By applying thermal stress to the substrate on which the layer 23 is laminated, the unevenness layer 24 and the sacrificial unevenness layer 25 are more reliably formed due to the difference in thermal expansion coefficient between the polymer and the metal.

Next, the sacrificial concavo-convex layer 25 made of a metal is removed by etching to leave only the uneven layer 24 made of the polymer (Fig. 4 (e)). In this embodiment, an aluminum etchant is used as an etchant, and wet etching is performed at a temperature of 40 占 폚 for 3 minutes to completely remove the sacrificial concavo-convex layer 25 made of a metal.

Here, in the case of using aluminum as the material of the sacrificial metal layer 25, an aluminum etchant which is easiest to remove the sacrificial asperity layer 25 is used as the etchant. However, as the material of the sacrificial metal layer 25, An appropriate etching solution which can easily remove the sacrificial metal layer may be used.

Subsequently, a substrate on which a plurality of uneven layers 24 are formed over the entire upper surface is obtained through a curing process. The curing process here is the same as in the first embodiment.

Next, in the same manner as in Embodiment 1, the first electrode, the organic light emitting layer, and the second electrode are formed on the opposite surface of the substrate 21 on which the uneven layer 24 is formed on one surface thereof, The necessary layers are sequentially formed and finally the sealing process is performed to fabricate the organic light emitting device.

The metal layer 23 is further formed on the polymer layer 22 and the thermal stress is applied to the polymer layer 22 and the metal layer 23 in addition to the ion impact stress, It is possible to easily form an uneven layer.

≪ Effect test &

In order to confirm the effect of the present invention, a sample of the organic light-emitting device of the present invention having the conventional organic light-emitting device free of the uneven layer on the light extraction surface side of the substrate and the uneven layer on the light extraction surface side of the substrate was prepared, The results will be described below.

(1) First, a light distribution distribution analysis showing the distribution of light was performed on the test sample according to the prior art and the test sample according to the present invention, and the result is shown in Fig.

A Goniophotometer manufactured by Pima Max Co., Ltd. was used for the measurement. As shown in FIG. 5, it can be seen that the light intensity distribution is significantly improved in the sample of the present invention having the uneven layer as compared with the sample of the prior art.

(2) Next, voltage-current efficiency characteristics were measured for a test sample according to the prior art and a test sample according to the present invention, and the results are shown in Fig.

As shown in FIG. 6, it can be seen that the current efficiency at the same voltage in the sample of the present invention having the unevenness layer is significantly improved compared to the sample of the prior art.

(3) The relation between the voltage-power efficiency was also measured for the test sample according to the prior art and the test sample according to the present invention, and the result is shown in Fig.

As can be seen from the graph of FIG. 7, it can be seen that the sample of the present invention having the unevenness layer significantly improved the power efficiency at the same voltage as compared with the sample having no uneven layer.

(4) Further, the emission spectra of the test samples according to the prior art and the test samples according to the present invention were measured. The results are shown in Fig.

As shown in the graph of FIG. 8, there was no particular change in the emission spectrum distribution in each wavelength region in the test sample according to the prior art and the test sample according to the present invention. Therefore, the light emitted from the organic light- It can be seen that there is no substantial change in color.

<Supplement>

(1) In Embodiment 1, the first electrode, the organic light emitting layer, and the second electrode are sequentially formed on the opposite surface of the uneven layer formation surface of the substrate having the uneven layer formed thereon, but the present invention is not limited thereto.

The uneven layer may be formed between the first electrode process and the organic light emitting layer forming process on the substrate.

(2) Embodiments 1 and 2 and Modifications illustrate preferred embodiments of the present invention, and the present invention is not limited to the above embodiments and modifications. It will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention.

(3) It is also possible to combine some or all of the embodiments and the modifications with each other.

10 organic light emitting device
11, 21 substrate
12, 22 polymer layer
23 metal layer
13, 24 uneven layer
25 sacrificial roughness layer

Claims (10)

A method of manufacturing an organic electroluminescent device,
Forming a polymer layer on the substrate;
Forming a concavo-convex layer on the polymer layer by applying ion-impact stress to the substrate on which the polymer layer is formed;
Forming a first electrode on a surface opposite to the uneven layer formation surface of the substrate;
Forming an organic light emitting layer on the first electrode;
And forming a second electrode on the organic light emitting layer. A method of manufacturing an organic electroluminescent device,
Forming a polymer layer on the substrate;
Forming a metal layer on the polymer layer;
Forming an irregularity by applying ion impact stress to the polymer layer and the substrate on which the metal layer is formed;
Removing the metal layer;
Forming a first electrode on a surface opposite to the uneven layer formation surface of the substrate;
Forming an organic light emitting layer on the first electrode;
And forming a second electrode on the organic light emitting layer. The method according to claim 1 or 2,
Wherein the ion bombardment stress is applied by an argon plasma method. The method of claim 2,
And applying heat stress to the substrate. The method of claim 4,
Wherein the application of the ion bombardment stress and the application of the thermal stress are simultaneously performed. The method of claim 4,
Wherein the ion bombardment stress is first applied, and then the thermal stress is applied. An organic electroluminescent device manufactured by the manufacturing method of claim 1 or 2. A substrate;
A first electrode formed on the substrate,
An organic light emitting layer formed on the first electrode,
And a second electrode formed on the organic light emitting layer,
The substrate has a plurality of uneven layers formed on the opposite surface of the first electrode,
Wherein the uneven layer is a layer formed by applying ion impact stress to the polymer layer formed on the substrate. A substrate;
A first electrode formed on the substrate,
An organic light emitting layer formed on the first electrode,
And a second electrode formed on the organic light emitting layer,
The substrate has a plurality of uneven layers formed on the opposite surface of the first electrode,
The uneven layer is a layer formed by applying ion shock stress to a polymer layer and a metal layer sequentially formed on the substrate,
Wherein the metal layer is removed after the ion bombardment stress is applied. The method of claim 9,
Wherein the uneven layer is a layer formed by applying ion stress stress and thermal stress to the polymer layer and the metal layer sequentially formed on the substrate.

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