KR101404159B1 - Method for manufacturing organic light emitting diode display - Google Patents

Abstract

The organic light emitting display according to the present invention includes a substrate, a particle layer disposed on the substrate, a first electrode positioned on the particle layer, a light emitting layer formed on the first electrode, and a second electrode formed on the light emitting layer, A particle member, and a filling member for filling the space between the particle members, wherein the particle member and the filling member have different refractive indices.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an organic light-

The present invention relates to an organic light emitting display and a method of manufacturing the same.

[0002] An organic light emitting diode (OLED) display is a self-emission type display device having an organic light emitting diode that emits light and displays an image. BACKGROUND ART [0002] Organic light emitting display devices are attracting attention as next-generation display devices for portable electronic devices because they exhibit high-quality characteristics such as low power consumption, high luminance, and high response speed.

Such an organic light emitting display includes a pair of electrodes located on both sides of an organic light emitting layer. One electrode of the pair of electrodes is a hole injecting electrode and the other is an electron injecting electrode. When excitons, which are injected into the organic light emitting layer and coupled with electrons, fall from the excited state to the ground state, light is emitted.

The light emitted from the organic light emitting layer is transmitted through the transparent electrode and the transparent substrate to be emitted to the outside. At this time, materials such as ITO (indium tin oxide) and IZO (indium zinc oxide) used as a substrate have a refractive index of 1.7 or more and 2.1 or less, and a glass substrate has a refractive index of 1.4 to 1.5, And the light is extinguished in the device, so that only about 20% of the light emitted from the organic light emitting layer is emitted to the outside of the substrate.

For this purpose, a pattern or concavo-convex structure of a high refractive index material is formed between the glass substrate and the transparent electrode, but the process for forming the pattern is complicated. In order to planarize them, a material layer such as a silicon oxide film is formed. However, since the refractive index is 1.4 to 1.5, the refractive index difference between the high refractive index material layer and the planarization oxide film is small and the light extraction efficiency is not high. The light extraction efficiency to be emitted to the outside is low and a method for increasing the light extraction efficiency is required.

Accordingly, it is an object of the present invention to provide an organic light emitting display device and a method of manufacturing the same, which can simplify a manufacturing method of an organic light emitting display device while improving light extraction efficiency.

According to an aspect of the present invention, there is provided an OLED display including a substrate, a particle layer disposed on the substrate, a first electrode disposed on the particle layer, a light emitting layer formed on the first electrode, And the particle layer includes a plurality of particle members, a filling member filling between the particle members, and the particle member and the filling member have different refractive indices.

The refractive index of the particles may be greater than the refractive index of the filler member and the refractive index of the particle member may be in the range of 1.6 to 2.5 and the refractive index of the filler member may be in the range of 1.3 to 1.6, have.

The filling member may include particles having a diameter of 50 nm or less.

The particle member may include at least one of ZrO ₂ , TiO ₂ , HfO ₂ , and ZnO, and the filling member may be made of silica.

The refractive index of the particle member may be less than the refractive index of the filler member, wherein the refractive index of the particle member is in the range of 1.3 to 1.6 and the refractive index of the filler member is in the range of 1.6 to 2.5.

The diameter of the particle member may be between 100 nm and 2 mu m, and the filler member may include particles with a diameter of 50 nm or less.

The particle member may be made of silica, and the filling member may include at least one of ZrO ₂ , TiO ₂ , HfO ₂ , and ZnO.

The intermediate layer may further include at least one of ZrO ₂ , TiO ₂ , HfO ₂ , ZnO, and SiN.

According to another aspect of the present invention, there is provided a method of manufacturing an organic light emitting diode display, including: forming a particle layer including a particle member and a filling member on a substrate; forming a first electrode on the particle layer; Forming a light emitting layer, and forming a second electrode on the light emitting layer, wherein the particle layer is formed by a solution process.

The solution process may be any one of a spin coating method, a dip coating method, a slit coating method, a bar coating method, a Langmuir Bladget method, and a doctor blading method.

The step of forming the particle layer may include applying a solvent including a particle member, removing the solvent, and applying a filler member to fill the gap between the particle members.

The step of removing the solvent may further include the step of etching the late particle member to reduce the size of the particle member.

And forming an intermediate layer on the particle layer.

The diameter of the particle member may be between 100 nm and 2 mu m, and the filler member may include particles with a diameter of 50 nm or less.

The filling member and the particle member may have different refractive indices.

The use of the particle layer as in the present invention can increase the light extraction efficiency of the OLED display.

In addition, since the particle layer can be formed without a separate additional process, the manufacturing process of the OLED display can be simplified.

1 is a cross-sectional view schematically illustrating an organic light emitting display according to an embodiment of the present invention.
2 is a cross-sectional view of a particle layer of an OLED display according to another embodiment of the present invention.
3 to 5 are cross-sectional views illustrating a method of manufacturing a particle layer of an organic light emitting diode display according to an embodiment of the present invention.
6 is a cross-sectional view schematically illustrating an organic light emitting display according to another embodiment of the present invention.
7 is a plan view schematically illustrating the structure of an OLED display according to an embodiment of the present invention.
8 is a circuit diagram showing a pixel circuit included in the organic light emitting diode display of FIG.
FIG. 9 is a cross-sectional view showing one pixel of the organic light emitting display device of FIGS. 7 and 8. FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

In the drawings, the thickness is enlarged to clearly represent the layers and regions. Like parts are designated with like reference numerals throughout the specification. Whenever a portion of a layer, film, region, plate, or the like is referred to as being "on" another portion, it includes not only the case where it is "directly on" another portion, but also the case where there is another portion in between. Conversely, when a part is "directly over" another part, it means that there is no other part in the middle.

Hereinafter, an organic light emitting diode display and a method of manufacturing the same according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a cross-sectional view schematically illustrating an organic light emitting diode display according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view of a particle layer of an OLED display according to another embodiment of the present invention.

1, an OLED display according to an embodiment of the present invention includes a substrate 111, a particle layer 300 located on the substrate 111, a first electrode 710 located on the particle layer 300, A light emitting layer 720 located on the first electrode 710, and a second electrode 730 located on the light emitting layer 720.

The substrate 111 is formed of a transparent material and may be a transparent glass substrate 111. In this case, the refractive index of the substrate 111 is approximately 1.5. The substrate 111 may be formed of quartz or a polymer film in a crystalline state in addition to glass.

The particle layer 300 includes a plurality of particle members 32, a filler member 34 that fixes the particle member 32 and fills between the particle members. The particle member 32 is substantially spherical, but may include irregularities on its surface as in Fig.

The particle member 32 and the filling member 34 have different refractive indices. That is, the refractive index of the particle member 32 may be larger or smaller than the refractive index of the filling member 34.

When the refractive index of the particle member 32 is in the range of 1.3 to 1.6, the refractive index of the filling member 34 may be in the range of 1.6 to 2.5. Where the particulate material 32 may be silica and may have a diameter of 100 nm to 2 占 퐉. And filling member 34 is ZrO _2, TiO _2, HfO _2, may include at least one of ZnO, and may be to fill the gap between the particles member 32 includes particles of 50nm or less, along with a solution Can be applied.

On the other hand, when the refractive index of the particle member 32 is 1.6 or more and 2.5 or less, the refractive index of the filling member 34 may be 1.3 or more and 1.6 or less.

At this time, the particle member 32 may include at least one of ZrO ₂ , TiO ₂ , HfO ₂ , and ZnO, and may have a diameter of 100 nm to 2 μm. And the filler member 34 may be silica and may have a particle size of 50 nm or less to fill the gaps between the particles 32.

3 to 5 are cross-sectional views illustrating a method of manufacturing a particle layer of an organic light emitting diode display according to an embodiment of the present invention.

The particle layer 300 of FIG. 1 can be applied simultaneously by mixing the particle member 32 and the filler member 34. At this time, the application can be applied by a spin coating method, a dip coating method, a slit coating method, a bar coating method, a Langmuir-Blodgett method, a doctor blading method and the like.

However, the particle layer 300 may be formed by applying the particle member 32 together with a solvent for coating as shown in FIG. 3, and then applying the filling member 34 as shown in FIG. At this time, the application can be applied by a spin coating method, a dip coating method, a slit coating method, a bar coating method, a Langmuir-Blodgett method, a doctor blading method and the like.

The coating solvent is an evaporable material after application, for example, water, ethanol, methanol, toluene, isopropyl alcohol, propylene glycol monomethyl ether acetate ), Methylisobutylketone, tetrahydrofuran, hexane, 4-methyl-2-pentanone, ketone, methylethylketone Propanol, butanol, pentanol, hexanol, dimethylsulfoxide, dimethylformamide, n-methyl pyrroolidone, and the like. At least one of acetone, acetonitrile, tetrahydrofuran, tecan, nonane, octane, heptane, and pentane may be included .

3, after the particle member 32 is coated and then dry-etched with oxygen or an etch gas containing fluorine such as CF ₄ and CF ₆ , the size of the particle member 32 is reduced as shown in FIG. 5 .

When the density of the particle member 32 is large and the gap between the particle members 32 is narrow, the size of the particle member 32 can be reduced by dry etching to increase the interval between the particle members 32. [

As described above, when the particle layer is formed as in the embodiment of the present invention, the total reflection of light generated in the organic light emitting display device can be reduced and the amount of light emitted to the outside of the substrate can be increased.

That is, a part of the light emitted from the light emitting layer is absorbed by the organic layer and the electrode layer in the light emitting layer, and is totally reflected on the inner surface of the substrate toward the light emitting layer, and the light extraction efficiency is lowered. In other words, due to the difference in refractive index between the transparent electrode 710 and the transparent substrate 111, a large amount of light is reflected in the device, and is thus extinguished. However, when a particle layer is formed as in the embodiment of the present invention, irregularities of the particle pattern are formed between the glass substrate and the transparent electrode, and the light diffuses in the concave-convex structure when the light passes through the substrate. Loss can be reduced.

At this time, if the refractive index difference between the particle member and the filling member in the particle layer is increased, the effect can be maximized, so that the light lost in the total reflection in the substrate can be reduced and the amount of light extracted through the substrate can be increased.

6 is a cross-sectional view schematically illustrating an organic light emitting display according to another embodiment of the present invention.

The organic light emitting display device of FIG. 6 is substantially identical to the interlayer structure of FIG. 1, so only the other portions will be described in detail.

6 includes a substrate 111, a particle layer 300 located on the substrate 111, a first electrode 710 located on the particle layer 300, a light emitting layer 720 located on the first electrode, And a second electrode 730 located above the light emitting layer 720.

The organic light emitting diode display of FIG. 6 further includes an intermediate layer 60 located on the particle layer 300, unlike the OLED display of FIG. At this time, the sum of the thicknesses of the particle layer 300 and the intermediate layer 60 is preferably 1 占 퐉 or less.

The intermediate layer 60 may include at least one of ZrO ₂ , TiO ₂ , HfO ₂ , ZnO, and SiN.

If the intermediate layer 60 is formed as in the embodiment of the present invention, it is possible to remove a step that may be formed on the surface of the particle layer 300 to facilitate a flat first electrode deposition process, and since there is little change in the refractive index with the first electrode The light transmitted from the light emitting layer can be transmitted to the particle layer without being lost due to reflection.

Since the intermediate layer is a material having the same refractive index as the particles or a third material having a refractive index between the particle and the first electrode material can be inserted into the intermediate layer, the third material can prevent the refractive index of the particle layer and the refractive index of the first electrode material If the material is between refractive indices, it can be more efficient in light extraction in terms of gradual change, rather than a sudden change in refractive index in the light path plane.

FIG. 7 is a plan view schematically showing the structure of an organic light emitting display according to an embodiment of the present invention, and FIG. 8 is a circuit diagram showing a pixel circuit included in the organic light emitting display of FIG.

As shown in FIG. 7, the OLED display includes a substrate 111 divided into a display area DA and a non-display area NA. A plurality of pixels PE are formed in the display area DA of the substrate main body to display an image and one or more driving circuits GD and DD are formed in the non-display area NA.

8, one pixel PE includes an organic light emitting diode 70, two thin film transistors (TFTs) 10 and 20, and one capacitor capacitor structure 80 having a 2Tr-1cap structure. However, an embodiment of the present invention is not limited thereto.

Accordingly, the organic light emitting display device may include three or more thin film transistors and two or more capacitors in one pixel (PE), and may be formed to have various structures by forming additional wirings. The thin film transistor and the capacitor further formed as described above can be configured as a compensation circuit.

The compensation circuit improves the uniformity of the organic light emitting element 70 formed for each pixel PE, thereby suppressing a variation in the image quality. In general, the compensation circuit includes two to eight thin film transistors.

The driving circuits GD and DD formed on the non-display area NA of the main body of the substrate 111 may also include additional thin film transistors.

The organic light emitting diode 70 includes an anode electrode as a hole injection electrode, a cathode electrode as an electron injection electrode, and a light emitting layer disposed between the anode electrode and the cathode electrode.

In one embodiment of the present invention, one pixel (PE) includes a first thin film transistor 10 and a second thin film transistor 20.

The first thin film transistor 10 and the second thin film transistor 20 include a gate electrode, a semiconductor layer, a source electrode, and a drain electrode, respectively. And the semiconductor layer of at least one of the first thin film transistor 10 and the second thin film transistor 20 includes an impurity-doped polycrystalline silicon film. That is, at least one of the first thin film transistor 10 and the second thin film transistor 20 is a polycrystalline silicon thin film transistor.

Although the capacitor line CL is shown in FIG. 8 together with the gate line GL, the data line DL and the common power line VDD, the capacitor line CL may be omitted in some cases.

A source electrode of the first thin film transistor 10 is connected to the data line DL and a gate electrode of the first thin film transistor 10 is connected to the gate line GL. The drain electrode of the first thin film transistor 10 is connected to the capacitor line CL through a capacitor 80. A node is formed between the drain electrode of the first thin film transistor 10 and the capacitor 80, and the gate electrode of the second thin film transistor 20 is connected. A common power line VDD is connected to the source electrode of the second thin film transistor 20 and an anode electrode of the organic light emitting diode 70 is connected to the drain electrode.

The first thin film transistor 10 is used as a switching element for selecting a pixel PE to emit light. When the first thin film transistor 10 is momentarily turned on, the capacitor 80 is charged, and the amount of charge charged at this time is proportional to the potential of the voltage applied from the data line DL. When the first thin-film transistor 10 is turned off and a voltage-rising signal is applied to the capacitor line CL one frame period, the gate potential of the second thin-film transistor 20 is charged to the capacitor 80 The level of the voltage applied based on the potential rises along the voltage applied through the capacitor line CL. The second thin film transistor 20 is turned on when the gate potential exceeds the threshold voltage. Then, a voltage applied to the common power line VDD is applied to the organic light emitting element 70 through the second thin film transistor 20, and the organic light emitting element 70 emits light.

Hereinafter, an organic light emitting display according to an embodiment of the present invention will be described in detail with reference to FIG.

FIG. 9 is a cross-sectional view showing one pixel of the organic light emitting display device of FIGS. 7 and 8. FIG.

In FIG. 9, the structure of the second thin film transistor 20 and the capacitor 80 of FIGS. 7 and 8 will be described in detail with reference to the stacking order. Hereinafter, the second thin film transistor 20 is referred to as a thin film transistor.

The substrate 111 may be an insulating substrate made of glass, quartz, ceramic, plastic, or the like.

On the substrate 111, a buffer layer 120 is formed.

The buffer layer 120 may be formed of a single layer of silicon nitride (SiNx) or a double-layer structure in which silicon nitride (SiNx) and silicon oxide (SiO2) are stacked. The buffer layer 120 serves to prevent the penetration of unnecessary components such as impurities or moisture and at the same time to flatten the surface.

On the buffer layer 120, a semiconductor 135 and a first capacitor electrode 138 made of polycrystalline silicon are formed.

The semiconductor 135 is divided into a channel region 1355 and a source region 1357 and a drain region 1356 formed on both sides of the channel region 1355. [ The channel region 1355 of the semiconductor 135 is an impurity-doped polycrystalline silicon, that is, an intrinsic semiconductor. The source region 1357 and the drain region 1356 of the semiconductor 135 are polycrystalline silicon doped with a conductive impurity, that is, an impurity semiconductor.

The first capacitor electrode 138 is doped with a conductive impurity.

The impurity doped in the source region 1357 and the drain region 1356 and the first capacitor electrode 138 may be any one of a p-type impurity and an n-type impurity.

A gate insulating layer 140 is formed on the semiconductor 135 and the first capacitor electrode 138. The gate insulating layer 140 may be a single layer or a plurality of layers including at least one of tetra ethyl orthosilicate (TEOS), silicon nitride, and silicon oxide.

A gate electrode 155 and a second capacitor electrode 158 are formed on the gate insulating layer 140. The gate electrode 155 overlaps the channel region 1355 and the second capacitor electrode 158 overlaps the first capacitor electrode 138. [

The first capacitor electrode 138 and the second capacitor electrode 158 constitute a capacitor 80 with the gate insulating film 140 as a dielectric.

An interlayer insulating layer 160 is formed on the gate electrode 155 and the second capacitor electrode 158. The interlayer insulating layer 160 may be formed of tetra ethyl orthosilicate (TEOS), silicon nitride, silicon oxide, or the like as the gate insulating layer 140.

The interlayer insulating film 160 and the gate insulating film 140 have a source contact hole 167 and a drain contact hole 166 that respectively expose a source region 1357 and a drain region 1356.

A source electrode 177 and a drain electrode 176 are formed on the interlayer insulating film 160. The source electrode 177 and the drain electrode 176 are connected to the source region 1357 and the drain region 1356 through the source contact hole 167 and the drain electrode hole 166, respectively.

A capacitor electrode (not shown) may be further formed on the interlayer insulating layer 160. An additional capacitor electrode may overlap the first capacitor electrode 138 or the second capacitor electrode 158 to increase the charge capacity.

A particle layer 300 is formed on the interlayer insulating film 160.

The particle layer 300 may be one of the particle layers of Figs. However, as shown in FIG. 6, the intermediate layer may be further included on the particle layer 300.

The formation of the particle layer as in the embodiment of the present invention can increase the efficiency of light transmitted to the outside of the substrate.

On the particle layer 300, a pixel electrode 710 and a pixel defining layer 190 of the organic light emitting diode 70 are formed. The pixel electrode 710 may be the first electrode of FIG.

The pixel electrode 710 is connected to the drain electrode 176 through the anode contact hole 186 of the planarization layer 180 and becomes the anode electrode of the organic light emitting diode. The pixel electrode 710 may be connected to the source electrode (not shown).

The pixel defining layer 190 has an opening 195 for exposing the pixel electrode 710. The pixel defining layer 190 may include a resin such as polyacrylates or polyimides, and a silica-based inorganic material.

A light emitting layer 720 is formed in the opening 195 of the pixel defining layer 190.

The light emitting layer 720 may include an organic light emitting layer, a hole-injection layer (HIL), a hole transporting layer (HTL), an electron transporting layer (ETL) EIL). ≪ / RTI >

When the light emitting layer 720 includes all of them, the hole injecting layer may be disposed on the pixel electrode 710, which is an anode electrode, and a hole transporting layer, a light emitting layer, an electron transporting layer, and an electron injecting layer may be sequentially stacked thereon.

A common electrode 730 is formed on the pixel defining layer 190 and the light emitting layer 720. The common electrode 730 is the second electrode in Fig.

The common electrode 730 becomes the cathode electrode of the organic light emitting element. Accordingly, the pixel electrode 710, the organic light emitting layer 720, and the common electrode 730 form the organic light emitting device 70.

Depending on the direction in which the organic light emitting diode 70 emits light, the organic light emitting display device may have any one of a front display type, a back display type, and a double-sided display type.

In the case of the front display type, the pixel electrode 710 is formed as a reflective film and the common electrode 730 is formed as a transmissive film or a semi-transmissive film. On the other hand, in the case of the backside display type, the pixel electrode 710 is formed of a transmissive film or a semi-transmissive film, and the common electrode 730 is formed of a reflective film. In the case of a double-sided display type, the pixel electrode 710 and the common electrode 730 are formed of a transmissive film or a semi-transmissive film.

The reflective film and the semi-transparent film may be formed using at least one of magnesium (Mg), silver (Ag), gold (Au), calcium (Ca), lithium (Li), chromium (Cr) Is made. The reflective film and the semi-transmissive film are determined to have a thickness, and the semi-transmissive film can be formed to a thickness of 200 nm or less. The thinner the thickness, the higher the transmittance of light, but if it is too thin, the resistance increases.

The transmissive film is made of a material such as ITO (indium tin oxide), IZO (indium zinc oxide), ZnO (zinc oxide), or In ₂ O ₃ (indium oxide).

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, Of the right.

10: first thin film transistor 20: second thin film transistor
32: particle member 34: filling member
70: organic light emitting device 80: capacitor
111: substrate 120: buffer layer
135: Semiconductor
138: first capacitor electrode 140: gate insulating film
155: gate electrode 158: second capacitor electrode
160: interlayer insulating film 180: planarization film
190: pixel defining layer 195: opening
300: particle layer
710: pixel electrode 720: organic light emitting layer
730: common electrode 1355: channel region
1356: drain region 1357: source region

Claims (20)

delete delete delete delete delete delete delete delete delete delete delete delete Forming a particle layer including a particle member and a filling member on a substrate,
Forming a first electrode on the particle layer,
Forming a light emitting layer on the first electrode,
Forming a second electrode on the light emitting layer
Lt; / RTI >
The step of forming the particle layer
Applying a solvent comprising the particulate material,
Removing the solvent,
Reducing the size of the particle member by etching the particle member,
Applying a filler to fill the gap between the particles,
Wherein the organic light emitting display device further comprises: The method of claim 13,
Wherein the step of applying the solvent is performed by any one of a sputtering method, a dip coating method, a slit coating method, a bar coating method, a Langmuir-Blodget method and a doctor blading method. delete delete The method of claim 13,
Forming an intermediate layer on the particle layer
Further comprising the steps of: The method of claim 13,
Wherein the particle member has a diameter of 100 nm to 2 占 퐉. The method of claim 18,
Wherein the filling member comprises particles having a diameter of 50 nm or less. The method of claim 13,
Wherein the filling member and the particle member have different refractive indices.

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