KR102295953B1 - Organic light emitting display device and method of manufacturing the same - Google Patents

Abstract

An organic light emitting display device and a method of manufacturing the organic light emitting display device are provided. A color filter is disposed on a substrate of the organic light emitting diode display. The overcoat layer is disposed on the color filter and includes a plurality of convex portions or a plurality of concave portions. The plurality of convex portions and the plurality of concave portions are arranged on the color filter to overlap the color filter. A step reducing layer is disposed on the overcoat layer. The step difference alleviating layer has a refractive index greater than that of the overcoat layer, and relieves the step difference caused by the plurality of convex portions and the plurality of concave portions. An organic light emitting device including an anode, an organic light emitting layer, and a cathode is disposed on the step alleviation layer. Since the step reducing layer having a refractive index greater than the refractive index of the overcoat layer is disposed between the overcoat layer and the anode, the light emitted from the organic light emitting layer is collected inside the total reflection critical angle in both the ITO mode and the substrate mode, and multiple reflection is prevented. By making this possible, the light extraction efficiency can be increased. In addition, since the plurality of convex portions and the plurality of concave portions of the overcoat layer are disposed to overlap the color filter and are disposed between the anode and the color filter, blurring and ghosting are eliminated, and optical interference caused by the circularly polarizing plate is also eliminated. can In addition, it is possible to prevent the anode and the cathode disposed on the overcoat layer from being shorted to each other by using the step difference alleviating layer for alleviating the step difference of the overcoat layer.

Description

Organic light emitting display device and organic light emitting display device manufacturing method

The present invention relates to an organic light emitting display device and a method for manufacturing an organic light emitting display device, and more particularly, to an organic light emitting display device having improved light extraction efficiency and a method for manufacturing an organic light emitting display device.

The organic light emitting display device is a self-emission type display device, and unlike a liquid crystal display device, it does not require a separate light source, so it can be manufactured in a lightweight and thin form. In addition, the organic light emitting diode display is being studied as a next-generation display because it is advantageous in terms of power consumption due to low voltage driving, and has excellent color realization, response speed, viewing angle, and contrast ratio (CR).

Light emitted from the organic light emitting layer of the organic light emitting diode display passes through various elements of the organic light emitting diode display and comes out of the organic light emitting diode display. However, among the light emitted from the organic light emitting layer, the light does not come out of the organic light emitting display device and is trapped inside the organic light emitting display device, so that the light extraction efficiency of the organic light emitting display device becomes a problem. In order to improve the light extraction efficiency of the organic light emitting diode display, a method of attaching a micro lens array (MLA) to the outside of the substrate of the organic light emitting display is used.

[Related technical literature]

1. Organic light emitting display device and its manufacturing method (Patent Application No. 10-2012-0100222)

The bottom emission type organic light emitting display device refers to an organic light emitting display device in which light emitted from the organic light emitting diode is emitted to the lower portion of the organic light emitting diode display. It refers to an organic light emitting diode display that is emitted toward a lower surface of a substrate on which a thin film transistor for driving the device is formed. Light emitted from the organic light emitting layer of the bottom emission type organic light emitting display device is largely based on a light propagation path in an ITO/organic mode (hereinafter, referred to as an 'ITO mode'), a substrate mode, and an air mode. can be divided into The air mode refers to light extracted from the organic light emitting layer among the light emitted from the organic light emitting layer, and the substrate mode refers to light that is trapped inside the organic light emitting diode display by total reflection and light absorption in the substrate among the light emitted from the organic light emitting layer. , and the ITO mode refers to light that is trapped inside the organic light emitting display device due to total reflection and light absorption at an anode generally formed of ITO among light emitted from the organic light emitting layer. In the bottom emission type organic light emitting display device, the light trapped inside the organic light emitting diode display in the ITO mode is about 50% of the light emitted from the organic light emitting layer, and the light trapped inside the organic light emitting display as the substrate mode is emitted from the organic light emitting layer. As about 30% of the emitted light, about 80% of the light emitted from the organic light emitting layer is trapped inside the organic light emitting display device, and only about 20% of the light is extracted to the outside, which improves the light extraction efficiency of the organic light emitting display device. Improving is a very important research area.

In order to solve the problem of light extraction efficiency of the organic light emitting diode display as described above, a technology for improving light extraction efficiency by attaching MLA to the outside of the substrate to extract light totally reflected by the difference in refractive index between the substrate and air to the outside of the substrate this exists

However, when the MLA is attached to the outside of the substrate, since the thickness of the substrate is generally significantly larger than the distance between the substrate and the anode, the light emitted from a specific pixel is extracted to the outside of the substrate through the MLA located in an area other than the corresponding pixel. , a blurring phenomenon and/or a ghost phenomenon may occur. In addition, even when the MLA is attached to the entire surface of the outside of the substrate, light emitted from a specific pixel is extracted to the outside of the substrate through the MLA located in an area other than the pixel, and blurring and/or ghosting may occur. In addition, a circular polarizer is used in the organic light emitting diode display to reduce reflection of external light. As the light passes through, the light is cancelled, resulting in a problem in which light extraction efficiency is reduced. Additionally, when the MLA is disposed outside the substrate, only light corresponding to the substrate mode from among the lights trapped inside the organic light emitting diode display can be extracted, and light corresponding to the ITO mode cannot be extracted.

Accordingly, the inventors of the present invention have invented a new structure capable of improving light extraction efficiency in a bottom-emission organic light emitting display device in order to solve problems that may occur when the MLA is disposed outside the substrate as described above. did.

SUMMARY OF THE INVENTION An object of the present invention is to provide an organic light emitting display device having improved device efficiency and a method for manufacturing an organic light emitting display by improving light extraction efficiency without image degradation and image quality degradation.

Another object of the present invention is to provide an organic light emitting display device and a method of manufacturing an organic light emitting display having a longer lifespan by improving light extraction efficiency.

The problems of the present invention are not limited to the problems mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the following description.

An organic light emitting diode display including an overcoat layer including a plurality of recesses and a step alleviation layer according to an exemplary embodiment is provided. A color filter is disposed on the substrate. The overcoat layer is disposed on the color filter and includes a plurality of convex portions or a plurality of concave portions. The plurality of convex portions and the plurality of concave portions are arranged on the color filter to overlap the color filter. A step reducing layer is disposed on the overcoat layer. The step difference alleviating layer has a refractive index greater than that of the overcoat layer, and relieves the step difference caused by the plurality of convex portions and the plurality of concave portions. An organic light emitting device including an anode, an organic light emitting layer, and a cathode is disposed on the step alleviation layer. Since the step reducing layer having a refractive index greater than the refractive index of the overcoat layer is disposed between the overcoat layer and the anode, the light emitted from the organic light emitting layer is collected inside the total reflection critical angle in both the ITO mode and the substrate mode, and multiple reflection is prevented. By making this possible, the light extraction efficiency can be increased. In addition, since the plurality of convex portions and the plurality of concave portions of the overcoat layer are disposed to overlap the color filter and are disposed between the anode and the color filter, blurring and ghosting are eliminated, and optical interference caused by the circularly polarizing plate is also eliminated. can In addition, it is possible to prevent the anode and the cathode disposed on the overcoat layer from being shorted to each other by using the step difference alleviating layer for alleviating the step difference of the overcoat layer.

According to an exemplary embodiment of the present invention, an organic light emitting diode display including a plurality of concave portions having a cut-off shape and a filling layer is provided. A color filter disposed on the substrate is disposed. The overcoat layer is disposed on the color filter, and includes a plurality of truncated shaped recesses. A plurality of cut-off-shaped recesses are arranged to overlap the color filter on the color filter, and expose the color filter. A fill layer is disposed on the overcoat layer. The filling layer has a refractive index greater than that of the overcoat layer, and fills at least a portion of the interior of the plurality of truncated recesses. A side surface of the concave portion of the shape in which a plurality of hem is cut off is an inclined curved surface. An organic light emitting device including an anode, an organic light emitting layer and a cathode is disposed on the filling layer. Since the refractive index of the filling layer disposed between the overcoat layer and the anode is greater than the refractive index of the overcoat layer, it is possible to reduce the trapping of light emitted from the organic light emitting layer in the ITO mode and the substrate mode. In addition, a plurality of truncated-shaped concave portions are arranged to expose the color filter, so that the light extraction efficiency in the ITO mode can be improved. In addition, the filling layer may fill at least a portion of the inside of the recessed portions of the plurality of truncated ends of the overcoating layer, so that the anode, the organic light emitting layer and the cathode disposed on the filling layer may be disposed in an embossed structure, whereby the organic light emitting display Current efficiency, driving voltage, power efficiency, etc. of the device may be improved.

According to an embodiment of the present invention, there is provided a method of manufacturing an organic light emitting diode display including an overcoat layer including a plurality of recesses and a step alleviation layer. A method of manufacturing an organic light emitting display device includes forming a color filter on a substrate, forming an overcoat layer including a plurality of convex portions or a plurality of concave portions overlapping the color filter on the color filter, and an overcoat layer on the overcoat layer forming a step alleviation layer having a refractive index greater than the refractive index of forming the device. By forming the step difference alleviating layer on the overcoat layer, it is possible to prevent the anode and the cathode formed on the overcoat layer from being short-circuited with each other.

An organic light emitting display device according to an embodiment of the present invention is provided. A color filter is disposed on the substrate. The overcoat layer is disposed on the color filter and includes a plurality of convex portions or a plurality of concave portions overlapping the color filter and having an aspect ratio of 0.25 or more and 0.6 or less. The organic light emitting device is disposed on an overcoat layer and includes an organic light emitting device including an anode, an organic light emitting layer disposed on the anode, and a cathode disposed on the organic light emitting layer. The organic light emitting device is disposed on a smooth non-planar surface having an aspect ratio of 0.25 or more and 0.6 or less, and the anode, the organic light emitting layer, and the cathode have a shape that follows the morphology of the smooth non-planar surface.

The details of other embodiments are included in the detailed description and drawings.

1A is a cross-sectional view illustrating an organic light emitting diode display including an overcoat layer including a plurality of recesses and a step alleviation layer according to an exemplary embodiment of the present invention.
FIG. 1B is an enlarged cross-sectional view of region X of FIG. 1A .
1C is an enlarged cross-sectional view illustrating shapes of an overcoat layer and a step difference alleviating layer different from those of FIG. 1B of an organic light emitting diode display according to an exemplary embodiment.
1D is an enlarged cross-sectional view illustrating an additional insulating layer of an organic light emitting diode display according to an exemplary embodiment.
FIG. 1E is a cross-sectional view illustrating an organic light emitting diode display including an overcoat layer including a plurality of convex portions and a step alleviation layer according to an exemplary embodiment of the present invention.
2A is a cross-sectional view illustrating an organic light emitting diode display including a plurality of truncated recesses and a filling layer according to an exemplary embodiment.
FIG. 2B is an enlarged cross-sectional view of region X of FIG. 2A .
3 is a flowchart illustrating a method of manufacturing an organic light emitting diode display including an overcoat layer including a plurality of recesses and a step alleviation layer according to an exemplary embodiment of the present invention.
4A to 4F are cross-sectional views illustrating a method of manufacturing an organic light emitting diode display including an overcoat layer including a plurality of recesses and a step alleviation layer according to an exemplary embodiment of the present invention.
5 is a graph illustrating a current efficiency increase rate of an organic light emitting diode display according to an aspect ratio of an overcoat layer including a plurality of concave portions according to an exemplary embodiment of the present invention.

Advantages and features of the present invention and methods of achieving them will become apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in a variety of different forms, and only these embodiments allow the disclosure of the present invention to be complete, and common knowledge in the technical field to which the present invention belongs It is provided to fully inform the possessor of the scope of the invention, and the present invention is only defined by the scope of the claims.

Reference to a device or layer “on” another device or layer includes any intervening layer or other device directly on or in the middle of another device.

Although first, second, etc. are used to describe various elements, these elements are not limited by these terms. These terms are only used to distinguish one component from another. Accordingly, the first component mentioned below may be the second component within the spirit of the present invention.

Like reference numerals refer to like elements throughout.

The size and thickness of each component shown in the drawings are illustrated for convenience of description, and the present invention is not necessarily limited to the size and thickness of the illustrated component.

Each feature of the various embodiments of the present invention may be partially or wholly combined or combined with each other, and technically various interlocking and driving are possible, as will be fully understood by those skilled in the art, and each embodiment may be independently implemented with respect to each other, It may be possible to implement together in a related relationship.

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

1A is a cross-sectional view illustrating an organic light emitting diode display including an overcoat layer including a plurality of recesses and a step alleviation layer according to an exemplary embodiment of the present invention. FIG. 1B is an enlarged cross-sectional view of region X of FIG. 1A . 1A and 1B , the organic light emitting diode display 100A includes a substrate 110A, a thin film transistor 120A, a color filter 150A, an overcoat layer 160A, a step reduction layer 170A, and an organic light emitting device. (140A). The organic light emitting diode display 100A illustrated in FIGS. 1A and 1B is a bottom emission type organic light emitting display device.

A thin film transistor 120A including a gate electrode 121A, an active layer 122A, a source electrode 123A, and a drain electrode 124A is formed on a substrate 110A made of an insulating material. Specifically, a gate electrode 121A is formed on the substrate 110A, and a gate insulating layer 131A for insulating the gate electrode 121A and the active layer 122A on the gate electrode 121A and the substrate 110A. ) is formed, an active layer 122A is formed on the gate insulating layer 131A, an etch stopper 132A is formed on the active layer 122A, and the active layer 122A and the etch star are formed. A source electrode 123A and a drain electrode 124A are formed on the fur 132A. The source electrode 123A and the drain electrode 124A are electrically connected to the active layer 122A in a manner in contact with the active layer 122A, and are formed on a partial region of the etch stopper 132A. In this specification, only the driving thin film transistor among various thin film transistors that may be included in the organic light emitting diode display 100A is illustrated for convenience of description. Also, in this specification, the thin film transistor 120A is described as having an inverted staggered structure, but a thin film transistor having a coplanar structure may also be used.

A passivation layer 133A is formed on the thin film transistor 120A, and a color filter 150A is formed on the passivation layer 133A. The color filter 150A is for converting the color of the light emitted from the organic emission layer 142A, and may be one of a red color filter, a green color filter, and a blue color filter. The color filter 150A may be formed of a material having a refractive index of about 1.5.

The color filter 150A is formed at a position corresponding to the light emitting area on the passivation layer 133A. Here, the light emitting region means an area in which the organic light emitting layer 142A emits light by the anode 141A and the cathode 143A, and the formation of the color filter 150A at a position corresponding to the light emitting area means that in adjacent light emitting areas. This means that the color filter 150A is disposed so that the emitted light is mixed with each other to prevent blurring and ghosting from occurring. For example, the color filter 150A may be formed to overlap the light emitting area, and specifically, may have a size equal to or smaller than the light emitting area. However, the formation position and size of the color filter 150A include not only the size and position of the light emitting region, but also the distance between the color filter 150A and the anode 141A, and the concave portion between the color filter 150A and the overcoat layer 160A. It may be determined by various factors, such as the distance between the 161A or the convex portions 163E, the distance between the light-emitting area and the light-emitting area, and the like.

An overcoat layer 160A is formed on the color filter 150A and the passivation layer 133A. The overcoat layer 160A is formed of an insulating material having a refractive index of about 1.5, for example, an acrylic resin, an epoxy resin, a phenol resin, a polyamide-based resin, a polyimide-based resin, an unsaturated polyester-based resin, or a polyphenylene-based resin. , polyphenylene sulfide-based resin, benzocyclobutene, and photoresist, but is not limited thereto, and may be formed of any insulating material having a refractive index of about 1.5.

The overcoat layer 160A includes a plurality of concave portions 161A formed to overlap the color filter 150A and a first connection portion 162A connecting the concave portions 161A adjacent to each other. The plurality of concave portions 161A has a hemispherical shape or a semi-ellipsoidal shape. 1A and 1B are cross-sectional views of a portion having a maximum height among a hemispherical shape or a semi-ellipsoidal shape of the plurality of concave portions 161A, wherein the plurality of concave portions 161A are illustrated in a semicircular shape. Referring to FIG. 1B , the diameter 2R of each of the plurality of concave portions 161A is about 1 to 5 μm, and the height D is about 1 to 4 μm. Referring to FIG. 1B , the first connecting portion 162A is a high portion between the concave portions 161A adjacent to each other. The overcoat layer 160A functions as a planarization layer in a portion where the plurality of concave portions 161A are not formed.

A step difference alleviating layer 170A is formed on the overcoat layer 160A. The step alleviation layer 170A is formed of a material having a refractive index greater than that of the overcoat layer 160A. The refractive index of the step alleviation layer 170A may be about 1.7 to 2.0. Specifically, in the step difference alleviating layer 170A, nanoparticles having a size of several tens of nm, such as _{titanium oxide (TiO 2} ), zirconium oxide (ZrO _{2 ), etc. having a refractive index greater than that of the polymer binder are dispersed in the polymer binder. or a layer in which nanoparticles such as titanium oxide (TiO 2} ), zirconium oxide (ZrO ₂ ), etc. having a refractive index greater than the refractive index of the photoresist are dispersed in the photoresist.

The step difference alleviating layer 170A is a layer for alleviating the step difference caused by the plurality of concave portions 161A of the overcoat layer 160A. That is, the step difference alleviating layer 170A is formed at a point between the plurality of concave portions 161A of the overcoat layer 160A and at a point where the inclination of the plurality of concave portions 161A is abrupt so that the organic light emitting diode 140A is not formed. In order to do this, it is a layer for partially filling the concave regions of the plurality of concave portions 161A of the overcoating layer 160A. In other words, the step difference alleviating layer 170A may smooth the curvature of the surface on which the organic light emitting diode 140A is formed.

As such, the surface on which the organic light emitting diode 140A is disposed may be the upper surface of the step difference alleviating layer 170A. The surface of the step difference alleviating layer 170A has a non-flat surface with a gentle slope, and thus the organic light emitting device 140A is formed on a non-flat surface with a gentle slope.

Referring to FIG. 1B , in order to alleviate the step difference caused by the plurality of concave portions 161A, the thickness h1 of the step difference alleviating layer 170A formed on the concave portion 161A of the overcoating layer 160A is determined by the overcoating layer ( The step difference alleviating layer 170A is formed to be greater than the thickness h2 of the step difference alleviating layer 170A formed on the first connection portion 162A of 160A.

Referring to FIGS. 1A and 1B , the step difference alleviating layer 170A is formed so that the top surface thereof is a non-planar surface. That is, the upper surface portion of the step difference alleviating layer 170A formed on the concave portion 161A of the overcoat layer 160A and the upper surface portion of the step difference alleviating layer 170A formed on the first connection portion 162A of the overcoat layer 160A. are on different planes, so that the upper surface of the step difference alleviating layer 170A is formed to be a non-planar surface. Accordingly, the organic light emitting diode 140 is formed on a non-flat surface with a gentle slope.

An organic light emitting diode 140A including an anode 141A, an organic light emitting layer 142A, and a cathode 143A and a bank 136A are formed on the step difference alleviating layer 170A. Specifically, an anode 141A for supplying holes to the organic light emitting layer 142A is formed on the upper surface of the step alleviation layer 170A, and an organic light emitting layer 142A is formed on the anode 141A, A cathode 143A for supplying electrons to the organic light emitting layer 142A is formed on the organic light emitting layer 142A. The anode 141A, the organic light emitting layer 142A, and the cathode 143A are formed along the shape of the top surface of the organic light emitting layer 142A, which is a non-planar surface, and have non-planarized upper and lower surfaces. For example, when the anode 141A, the organic emission layer 142A, and the cathode 143A are formed by a deposition method, the anode 141A, the organic emission layer 142A, and the cathode 143A are the anode 141A and the organic emission layer. Each of the 142A and the cathode 143A is formed in a shape conforming to the morphology of the surface to be formed. The anode 141A is formed of a transparent conductive oxide having a high work function, such as ITO, and the cathode 143A is formed of a metallic material having a low work function. In the present specification, since the organic light emitting diode display 100A is a bottom emission type organic light emitting display device, the metallic material constituting the cathode 143A must be a material having excellent reflectivity.

In some embodiments, the plurality of concave portions 161A of the overcoat layer 160A themselves have a smooth morphology, so that the step reducing layer 170A is interposed between the overcoat layer 160A and the anode 141A. The organic light emitting device 140A including the anode 141A, the organic light emitting layer 142A, and the cathode 143A and the bank 136A may be formed on the overcoating layer 160A without being formed.

In this case, moisture or the like due to outgassing from the overcoat layer 160A may be directly diffused into the organic light emitting device 140A to cause deterioration of the organic light emitting device 140A. To prevent this, a second passivation layer (not shown) may be additionally deposited to a thickness of several tens to several hundred nm. The second passivation layer preferably has the same or similar refractive index as that of the anode 141A in the overcoat layer 160A. For example, the refractive index of the second passivation layer has a value closer to the refractive index of the anode 141A than the refractive index of the overcoat layer 160A. The second passivation layer (not shown) should be made of an insulating inorganic material, and may be, for example, silicon nitride. When the second passivation layer (not shown) is disposed on the overcoat layer 160A by the deposition method, the second passivation layer (not shown) having a shape following the morphology of the concave portion 161A of the overcoat layer 160A is is formed

That is, each of the plurality of concave portions 161A of the overcoating layer 160A may be manufactured in a shape in which the edges are not sharp, so that the surface on which the organic light emitting diode 140A is formed may be gently curved. The organic light-emitting device 140A and the bank 136A are formed directly on the over-coating layer 160A without the step difference alleviating layer 170A interposed between the over-coating layer 160A and the anode 141A, or the over-coating layer ( The organic light emitting diode 140A and the bank 136A may be formed on the overcoat layer 160A without the step difference alleviating layer 170A interposed between the 160A) and the anode 141A.

Accordingly, the surface on which the organic light emitting diode 140A is disposed in the organic light emitting diode display 100A according to the exemplary embodiment of the present invention has an overcoat layer having a smooth morphology in which the concave portion 161A of the overcoat layer 160A itself has a smooth morphology. 160A). Alternatively, in the organic light emitting diode display 100A, the surface on which the organic light emitting device 140A is disposed is the top surface of the second passivation layer (not shown) having a shape following the morphology of the concave portion 161A of the overcoat layer 16A. can In this case, the overcoat layer 160A or the second passivation layer (not shown) has a non-flat surface with a gentle slope, and thus the organic light emitting diode 140A is formed on a non-flat surface with a gentle slope.

As the resolution of the organic light emitting diode display increases, the pixel size of the organic light emitting display decreases and the number of pixels increases. Accordingly, power required to emit light of the same luminance is increased in a high-resolution organic light-emitting display device compared to an organic light-emitting display device having a relatively low resolution, and the lifespan of the organic light-emitting device may be problematic. Accordingly, in the organic light emitting diode display 100A according to an embodiment of the present invention, since the organic light emitting layer 142A is formed to have non-planar top and bottom surfaces, the organic light emitting layer 142A is compared with the planarized organic light emitting layer 142A. Therefore, since the light emitting area is increased, the voltage and current for emitting light of the same luminance may be reduced, power may also be reduced, and the lifespan of the organic light emitting diode 140A may be increased.

The aspect ratio of the cathode 143A formed on the concave portion 161A of the overcoat layer 160A among the cathodes 143A of the organic light emitting diode 140A is about 0.5 or more and 0.7 or less. Referring to FIG. 1B , the aspect ratio of the cathode 143A means a value obtained by dividing the height M of the cathode 143A formed on the concave portion 161A by the radius N of the cathode 143A.

The organic emission layer 142A is formed in a tandem white structure in which a plurality of organic emission layers are stacked to emit white light. The organic light emitting layer 142A includes a first organic light emitting layer that emits blue light and a second organic light emitting layer that is formed on the first organic light emitting layer and emits white light by mixing with blue light. The second organic emission layer may be, for example, an organic emission layer emitting yellow-green light.

In general, in order to increase light extraction efficiency of an organic light emitting diode display, a micro-cavity effect is applied. The microcavity effect refers to a method of increasing light extraction efficiency by using light reflectivity and optical constructive interference of an electrode. The microcavity effect is implemented by a method that satisfies a specific optical condition in which a wavelength corresponding to a specific color is reinforced while being reflected between the reflective electrode and the transflective electrode. By adjusting the distance between the reflective electrode and the transflective electrode, that is, the thickness of the organic light emitting layer, a wavelength to be reinforced may be selected. Theoretically, when an integer multiple of the wavelength corresponding to a specific color is an even multiple of the thickness of the organic light emitting layer, constructive interference of the wavelength corresponding to the specific color occurs. In this case, the constructive interference condition is expressed as an equation as follows.

2nd = mλ

(n, m = integer, m = order of wavelength, d = thickness of organic light emitting layer, λ = reference wavelength at which constructive interference occurs)

In order to apply the microcavity effect to the organic light emitting device, first, an optimum point of a region where light corresponding to a wavelength to be reinforced from the transflective electrode and the reflective electrode emits is calculated. Then, the overall thickness of the organic light emitting layer is calculated in consideration of the constructive interference condition. If the organic light emitting device is designed by reflecting this, light extraction efficiency of a wavelength corresponding to a specific color may be improved.

Due to the optical conditions for implementing the microcavity effect, the thickness of the organic light emitting layer is limited. For example, in the case in which the organic light emitting layer is formed in a structure in which two organic light emitting layers are stacked to emit white light, in order to increase light extraction efficiency by applying the microcavity effect, the organic light emitting layer of about 350 or more and 400 nm or less is It should have the thickness of the light emitting layer. That is, when the organic light emitting layer is formed in a structure in which two organic light emitting layers are stacked to emit white light, in order for the organic light emitting device to satisfy the optical condition for realizing the microcavity effect, the thickness of the organic light emitting layer is 350 nm should be more than Furthermore, as the number of the stacked organic light emitting layers increases, the thickness of the organic light emitting layer according to optical conditions for realizing the microcavity effect inevitably increases dramatically. As the thickness of the organic light emitting layer increases, the manufacturing cost and manufacturing time of the organic light emitting diode increase, and the driving voltage and power consumption for driving the organic light emitting display device also increase.

As a result, when the microcavity effect is applied as a method of increasing the light extraction effect, the driving voltage and power consumption increase according to the increase in the thickness of the organic light emitting layer, and the power efficiency decreases in comparison with the other cases. do.

However, in the organic light emitting diode display 100A according to an embodiment of the present invention, light extraction efficiency is increased by applying the overcoat layer 160A and the step difference alleviation layer 170A, not the microcavity effect. Accordingly, in the organic light emitting diode display 100A according to an embodiment of the present invention, there is no need to optimize the thickness of the organic light emitting layer 142A according to optical conditions for realizing the microcavity effect in order to increase light extraction efficiency. As a result, the thickness of the organic light emitting layer 142A can be remarkably reduced. That is, the organic light emitting device 140A of the organic light emitting diode display 100A according to an exemplary embodiment may have a thickness of the thin organic light emitting layer 142A of 350 nm or less.

Light emitted from the first organic light emitting layer positioned below the organic light emitting layer 142A has a higher ratio of the light trapped therein in the ITO mode compared to the light emitted from the second organic light emitting layer positioned above. In the organic light emitting display device 100A according to an embodiment of the present invention, the organic light emitting layer 142A is formed in a structure in which a plurality of organic light emitting layers are stacked to emit white light, and the first organic light emitting layer is disposed below the organic light emitting layer. Since the organic light emitting layer is an organic light emitting layer emitting blue light, it is possible to reduce the trapping of blue light emitted from the first organic light emitting layer in the ITO mode. Accordingly, not only the overall light efficiency of the organic light emitting diode display 100A can be improved, but also the light efficiency of blue light, which is a problem in a general organic light emitting display device, can be improved.

When the plurality of concave portions 161A are formed in the overcoating layer 160A through a process such as photolithography, the overcoating layer 160A is sharp as in the first connecting portion 162A shown in FIG. 1B ( peaky), there is a part where the morphology changes rapidly. However, the organic light emitting layer 142A of the organic light emitting device 140A is formed in a manner that deteriorates the step coverage of the organic light emitting layer 142A, such as a thermal evaporation method, and the organic light emitting layer 142A has a thickness of several hundred nm. Since it is formed to a very thin thickness, a region in which an organic light emitting layer is not formed may occur on the anode, and accordingly, there is a high probability that the anode and the cathode are short-circuited. In the organic light emitting diode display 100A according to an embodiment of the present invention, the step alleviation layer 170A for alleviating the step difference caused by the plurality of concave portions 161A of the overcoat layer 160A is adopted, and the overcoat layer 160A is used. It is possible to greatly reduce the probability that a short circuit between the anode 141A and the cathode 143A occurs due to the shape of .

In the organic light emitting diode display 100A according to an embodiment of the present invention, a step alleviation layer 170A having a refractive index of about 1.7 to 2.0, which is a larger refractive index than that of the overcoat layer 160A, is formed on the overcoat layer 160A. do. In general, since the refractive index of ITO used as the anode 141A is about 1.7, and the refractive index of the overcoat layer 160A is about 1.5, the light emitted from the organic light emitting layer 142A is the anode 141A and the step difference mitigating layer 170A. Total reflection may not occur at the interface of , and total reflection may occur at the interface between the step difference alleviating layer 170A and the over-coating layer 160A. However, the overcoat layer 160A of the organic light emitting diode display 100A according to an exemplary embodiment has a plurality of concave portions 161A, and the step alleviation layer 170A includes a plurality of concave portions 161A. Since it is formed on the overcoat layer 160A, the overcoat layer 160A and the step difference alleviation layer 170A may form an MLA structure. Accordingly, the incident angle of the light emitted from the organic light emitting layer 142A incident on the interface between the step alleviation layer 170A and the overcoat layer 160A is highly likely to be smaller than the total reflection critical angle, so that the inside of the organic light emitting diode display 100A in the ITO mode. It is possible to reduce the amount of light trapped in the In addition, the light emitted from the organic emission layer 142A passes through the interface between the step difference alleviating layer 170A and the overcoat layer 160A and proceeds at an angle close to perpendicular to the lower surface of the substrate 110A (L1 in FIG. 1B ). Reference). Accordingly, it is highly probable that light passing through the interface between the step alleviation layer 170A and the overcoat layer 160A is smaller than the total reflection critical angle even in the substrate mode, so the amount of light trapped inside the organic light emitting diode display 100A in the substrate mode may reduce In addition, by enabling multiple reflection of light emitted at the interface between the step alleviation layer 170A and the overcoat layer 160A, the light is recycled to meet the MLA structure of the overcoat layer 160A and the step alleviation layer 170A. The number may be increased. Accordingly, the amount of light trapped inside the organic light emitting diode display 100A can be reduced by the ITO mode and the substrate mode, so that light extraction efficiency is increased and the lifespan of the organic light emitting diode 140A is also increased.

As described above, in the organic light emitting diode display 100A according to an embodiment of the present invention, the overcoat layer 160A including the plurality of concave portions 161A and the step difference alleviation layer 170A form an MLA structure, This structure is formed between the color filter 150A and the anode 141A. Accordingly, compared to a structure in which the MLA structure is disposed on the outside of the substrate 110A, in the organic light emitting diode display 100A according to an embodiment of the present invention, blurring or ghosting may be eliminated, and the overcoat layer 160A may be removed. ) and the step difference alleviating layer 170A, it is possible to prevent the light reflected into the organic light emitting display device 100A from passing through the circular polarizer and being canceled. In addition, in the organic light emitting diode display 100A according to an embodiment of the present invention, since the plurality of concave portions 161A of the overcoat layer 160A overlap the color filter 150A, blurring or ghosting is prevented. can be removed.

When the aspect ratio of the concave portion 161A of the overcoat layer 160A becomes 1 or more, the inclination of the sharp edge becomes sharp as in the first connection portion 162A illustrated in FIG. 1B . In the case of an organic light emitting display device including the overcoat layer 160A whose morphology is rapidly changed as described above, even when the step difference alleviating layer 170A is formed on the overcoat layer 160A, the organic light emitting layer 142A is over At the point of the first connection portion 162A of the concave portion 161A of the coating layer 160A, it may not be continuously formed and may be cut off. Accordingly, a phenomenon in which the anode 141A and the cathode 143A are partially shorted occurs, or the anode 141A and the cathode 143A are not shorted even if the cathode 143A is also the overcoat layer 160A. At the point of the first connection portion 162A of the concave portion 161A, it may not be continuous and may be broken.

That is, as the edge of each of the concave portions 161A of the overcoat layer 160A is sharp, the organic light emitting layer 142A and/or the cathode 143A formed on the concave portion 161A of the overcoat layer 160A is partially cut off. A point may occur. A short circuit occurs between the anode 141A and the cathode 143A of the organic light emitting diode 140A, or the cathode 143A is not smoothly energized. At a point where the organic light emitting layer 142A and/or the cathode 143A formed on the concave portion 161A of the overcoating layer 160A is partially cut off, the organic light emitting device 140A does not emit light. The luminous efficiency of the device 140A is reduced.

In order to solve the problem according to the shape of the concave portion 161A of the overcoat layer 160A, in the organic light emitting diode display 100A according to an embodiment of the present invention, the concave portion 161A of the overcoat layer 160A is Although the step difference alleviating layer 170A serving to compensate for the aspect ratio may be formed on the recessed portion 161A of the overcoating layer 160A, the overcoat having the recessed portion 161A of the overcoating layer 160A does not require step compensation. A coating layer 160A may be formed.

In the latter case, the organic light emitting device 140A including the anode 141A, the organic light emitting layer 142A, and the cathode 143A and the bank are formed on the overcoat layer 160A without interposing the step difference alleviating layer 170A. can be That is, when the edge of the concave portion 161A of the overcoat layer 160A is not sharp but gentle, the anode 141A, the organic light emitting layer 142A, and the cathode 143A are formed as an organic light emitting device without the step difference alleviating layer 170A. 140A and a bank 136A may be formed.

To this end, as in the first connection part 162A shown in FIG. 1B , the inclination of the sharp edge should be more gently formed. That is, the morphology of the concave portion 161A of the overcoat layer 160A should be formed more gently.

The shape of the concave portion 161A of the overcoat layer 160A is formed through a process such as photolithography, and the morphology of the concave portion 161A of the overcoat layer 160A is adjusted by adjusting the heat treatment process performed at this time. can be adjusted.

In more detail, it is as follows. In order to form the concave portion 161A of the overcoat layer 160A, photoresist is applied, patterned into a concave shape through a photolithography process, and then heat treatment is performed. In this case, the shape of the concave portion 161A of the overcoat layer 160A may be formed by performing the heat treatment step by step over two steps, rather than performing the heat treatment at once. For example, before performing the final heat treatment in the vicinity of about 200 °C or more and 250 °C or less, the intermediate heat treatment at about 100 °C or more and 130 °C or less should first be performed.

At this time, the time for performing the intermediate heat treatment is related to the morphology of the concave portion 161A of the overcoat layer 160A. As the time for performing the intermediate heat treatment increases, the morphology of the concave portion 161A of the finally formed overcoat layer 160A increases. In the extreme, when only the final heat treatment is immediately performed without the time for performing the intermediate heat treatment, the morphology of the concave portion 161A of the overcoat layer 160A is lost and the overcoat layer 160A is planarized.

By using this tendency, various organic light emitting display devices having different morphologies of the concave portion 161A of the overcoat layer 160A were manufactured. Using this, when the concave portion 161A of the over-coating layer 160A has a certain morphology, that is, when the concave portion 161A of the over-coating layer 160A has a certain aspect ratio, the organic light emitting device 140A achieves the maximum An experiment was conducted to see if it could operate with luminous efficiency. Next, we will look at the experimental results with reference to FIG. 5 .

FIG. 5 is a diagram illustrating a relationship between current efficiency enhancement (%) of organic light emitting display devices having various values of the aspect ratio of the concave portion 161A of the overcoat layer 160A. It is a graph. In this case, the higher the current efficiency increase rate, the better the luminous efficiency.

When the aspect ratio of the concave portion 161A of the overcoating layer 160A has a value of about 0.25 or more and less than or equal to 0.6, the current efficiency is higher than when the aspect ratio of the concave portion 161A of the overcoat layer 160A has a value greater than 0.6. It can be seen that the increase rate is more excellent. Rather, when the aspect ratio of the concave portion 161A of the overcoat layer 160A has a value greater than about 0.6, it can be seen that the current efficiency increase rate tends to decrease.

Judging from the trend of FIG. 5 , it can be seen that the current efficiency increase rate is maximum when the aspect ratio of the concave portion 161A of the overcoat layer 160A has a value between about 0.3 or more and 0.5 or less.

Accordingly, the aspect ratio of the concave portion 161A of the overcoat layer 160A on the surface on which the organic light emitting device 140A is disposed in the illustrated organic light emitting display device 100A according to an exemplary embodiment is about 0.25 or more and about 0.6. It may be the upper surface of the overcoat layer 160A having a value between the following. Alternatively, in the illustrated organic light emitting diode display 100A according to an exemplary embodiment, the surface on which the organic light emitting diode 140A is disposed has an aspect ratio of the concave portion 161A of the overcoat layer 160A of about 0.25 or more and about 0.6. It may be the upper surface of the second passivation layer (not shown) that follows the morphology of the overcoat layer 160A having a value between the following. That is, the surface of the overcoat layer 160A or the second passivation layer (not shown) at this time is a smooth non-flat surface having an aspect ratio of about 0.25 or more and about 0.6 or less, and thus the organic light emitting device 140A is The aspect ratio is formed on a gently non-planar surface having a value between about 0.25 and about 0.6 or less, and the anode 141A, the organic light emitting layer 142A, and the cathode 143A have a shape following the morphology of the gentle non-flat surface. do.

In summary, in forming the concave portion 161A of the overcoat layer 160A, the first connection portion 162A of the concave portion 161A of the overcoat layer 160A is formed by taking the intermediate heat treatment process a little short. It can be formed to have a gentle slope. According to this method, when the overcoat layer 160A is formed such that the aspect ratio of the concave portion 161A of the overcoat layer 160A has a value of 0.25 or more and 0.6 or less, there is no need to interpose the step difference alleviating layer 170A. An organic light emitting diode 140A including an anode 141A, an organic emission layer 142A, and a cathode 143A and a bank 136A may be formed on the 160A. At this time, although not shown, as described above, the morphology of the concave portion 161A of the overcoating layer 160A is maintained while blocking outgassing from the overcoating layer 160A from being diffused to the organic light emitting device 140A. A second passivation layer (not shown) having a shape that follows and a refractive index similar to that of the anode 141A may be added between the overcoat layer 160A and the anode 141A.

Since the organic light emitting diode display 100A according to an embodiment of the present invention is a bottom emission type organic light emitting display device, the cathode 143A is formed of a metallic material having excellent reflectivity, so that light emitted from the organic light emitting layer 142A is It is reflected from the cathode 143A and travels toward the substrate 110A, and the cathode 143A of the organic light emitting diode display 100A has a non-planar top and bottom surface. Specifically, the cathode 143A formed on the concave portion 161A of the overcoat layer 160A among the cathodes 143A has an upper surface and a lower surface that are non-planarized to have an aspect ratio of about 0.5 or more and 0.7 or less.

Accordingly, according to the deformation of the surface shape of the cathode 143A, the propagation angle of the light emitted from the organic light emitting layer 142A reflected from the cathode 143A and directed toward the anode 141A is the overcoat layer 160A and the step difference alleviating layer 170A. ) is more likely to be smaller than the critical angle of total reflection at the interface (see L2 in FIG. 1B ). Accordingly, since the amount of light trapped inside the organic light emitting diode display 100A can be reduced, voltage and current for emitting light of the same luminance are reduced, power is also reduced, and the lifespan of the organic light emitting diode 140A is reduced. can be increased.

1A and 1B show only a cross-sectional view and a cross-sectional enlarged view of the organic light emitting diode display 100A, but the plurality of concave portions 161A of the overcoat layer 160A of the organic light emitting display apparatus 100A is formed by the color filter 150A. ) may be arranged in a hexagonal structure on a plane.

1A and 1B show that the passivation layer 133A planarizes the upper part of the thin film transistor 120A, but the passivation layer 133A does not planarize the upper part of the thin film transistor 120A, and the surfaces of the elements located below It may be formed according to a shape. Also, although the passivation layer 133A is illustrated as being included in the organic light emitting diode display 100A in FIGS. 1A and 1B , the passivation layer 133A is not used and an overcoat layer directly on the thin film transistor 120A. 160A may be formed.

1A and 1B show that the color filter 150A is formed on the passivation layer 133A, but the present invention is not limited thereto. It may be formed at any position between the lower portion of the layer 170A and the substrate 110A.

The overcoat layer 160A may be manufactured together with the color filter 150A during the organic light emitting display device 100A manufacturing process, and the overcoat layer 160A is patterned according to manufacturing process conditions so that the overcoat layer 160A has a plurality of recesses. It may be difficult to have the portion 161A. In this case, the plurality of concave portions 161A are not directly formed on the overcoat layer 160A, but a separate photoresist is applied on the overcoat layer 160A, and a separate photoresist is patterned to form a separate photoresist. The step difference alleviating layer 170A and the MLA structure may be formed having a plurality of concave portions.

1C is an enlarged cross-sectional view illustrating shapes of an overcoat layer and a step difference alleviating layer different from those of FIG. 1B of an organic light emitting diode display according to an exemplary embodiment. Compared to the organic light emitting diode display 100A of FIGS. 1A and 1B , the organic light emitting diode display 100C of FIG. 1C has only the shapes of the overcoat layer 160C and the step difference alleviating layer 170C different from those of the organic light emitting display device 100A of FIGS. 1A and 1B , and the other configurations are substantially different. Since they are the same, duplicate descriptions are omitted.

Referring to FIG. 1C , each of the plurality of concave portions 161C of the overcoat layer 160C overlaps the concave portions 161C adjacent to each other. In FIG. 1C , a portion where the concave portion 161C overlaps and is removed is illustrated by a dotted line. A diameter 2R of each of the plurality of concave portions 161C of the overcoat layer 160C is greater than or equal to a distance S between centers of the concave portions 161C adjacent to each other. When the plurality of concave portions 161C have a hemispherical shape, the diameter of the hemispherical shape is greater than or equal to the distance S between the centers of the hemispherical shapes adjacent to each other. The diameter of the semi-ellipsoid shape is greater than or equal to the distance (S) between the centers of adjacent semi-ellipsoid shapes. Here, the diameter 2R of the concave portion 161C means the diameter in a state in which the concave portion 161C overlaps the concave portion 161C adjacent to each other and is not removed, and the center of the concave portion 161C is a hemisphere. It means the lowest point of the concave portion 161C in the shape or semi-ellipsoidal shape.

When the plurality of concave portions 161C overlap each other, the pitch between the concave portions 161C adjacent to each other is smaller than when the plurality of concave portions 161C do not overlap each other. In addition, as the pitch between the plurality of concave portions 161C decreases, the size of the grating vector increases. Accordingly, in the organic light emitting diode display 100C according to the exemplary embodiment of the present invention, the concave portions 161C adjacent to each other are formed to overlap each other, thereby increasing the size of the grating vector, thereby further increasing the light extraction effect. .

1D is an enlarged cross-sectional view illustrating an additional insulating layer of an organic light emitting diode display according to an exemplary embodiment. The organic light emitting diode display 100D of FIG. 1D is different from the organic light emitting display device 100A of FIGS. 1A and 1B except that it further includes an insulating layer 134D, and other configurations are substantially the same. A duplicate description will be omitted.

An insulating layer 134D is further formed between the passivation layer 133D and the color filter 150D. The insulating layer 134D has a refractive index smaller than the refractive index of the overcoat layer 160D and the refractive index of the color filter 150D. The insulating layer 134D may be formed of a fluorinated polymer having a refractive index of about 1.3 to 1.4, for example, lithium fluoride (LiF), but is not limited thereto, and is formed of any material having a refractive index of about 1.3 to 1.4. can be

Since the refractive index of the color filter 150D is about 1.5 and the refractive index of the insulating layer 134D formed under the color filter 150D is about 1.3 to 1.4, the incident angle of the light emitted from the organic light emitting layer 142D is greater than the critical angle of total reflection. Light incident on the interface between the color filter 150D and the insulating layer 134D is totally reflected at the interface between the color filter 150D and the insulating layer 134D. In the organic light emitting diode display 100D according to an exemplary embodiment, when the insulating layer 134D is not used, an incident angle of light emitted from the organic light emitting layer 142D and passing through the color filter 150D is greater than the total reflection critical angle. The light that is totally reflected at the interface between the substrate 110D and the air is totally reflected at the interface between the color filter 150D and the insulating layer 134D and goes back to the MLA structure of the step alleviation layer 170D and the overcoat layer 160D. , may be changed to light traveling at an incident angle smaller than the critical angle of total reflection at the interface between the substrate 110D and air by passing through the MLA several times. Accordingly, in the organic light emitting diode display 100D according to an embodiment of the present invention, the insulating layer 134D having a refractive index smaller than that of the overcoat layer 160D and the color filter 150D is used to enter the substrate mode. Light extraction efficiency with respect to light trapped inside the organic light emitting diode display 100D may be increased.

Although the insulating layer 134D is illustrated as being formed on the passivation layer 133D in FIG. 1D , the insulating layer 134D may be formed at another position between the substrate 110D and the color filter 150D.

Although FIG. 1D illustrates that the insulating layer 134D is formed between the color filter 150D and the passivation layer 133D, an air gap may be formed instead of the insulating layer 134D. That is, a space filled with air may be formed between the color filter 150D and the passivation layer 133D. Since the refractive index of air is smaller than that of the color filter 150D, the air gap 480 may generate the same effect as the above-described insulating layer 134D. Also, the air gap 480 may be formed at another position between the substrate 110D and the color filter 150D, similar to the insulating layer 134D.

FIG. 1E is a cross-sectional view illustrating an organic light emitting diode display including an overcoat layer including a plurality of convex portions and a step alleviation layer according to an exemplary embodiment of the present invention. Compared to the organic light emitting diode display 100A of FIGS. 1A and 1B , the organic light emitting diode display 100E of FIG. 1E includes the overcoat layer 160E including a plurality of convex portions 163E and the step difference alleviating layer 170E. Only the shapes of are different, and other configurations are substantially the same, so a redundant description will be omitted.

The overcoat layer 160E includes a plurality of convex parts 163E formed to overlap the color filter 150E and a second connection part 164E connecting the convex parts 163E adjacent to each other. The plurality of convex portions 163E have a hemispherical shape or a semi-ellipsoidal shape. FIG. 1E is a cross-sectional view of a portion having a maximum height among a hemispherical shape or a semi-ellipsoidal shape of the plurality of convex parts 163E, wherein the plurality of convex parts 163E are shown in a semicircular shape. The diameter and height of the plurality of convex portions 163E may be the same as the diameter 2R and height D of the plurality of concave portions 161A illustrated in FIGS. 1A and 1B .

A step difference alleviating layer 170E is formed on the overcoat layer 160E. The step difference alleviating layer 170E is a layer for alleviating the step difference caused by the plurality of convex portions 163E of the overcoat layer 160E. Referring to FIG. 1E , in order to alleviate the step difference caused by the plurality of convex portions 163E, the thickness h1 of the step difference alleviating layer 170E formed on the convex portions 163E of the overcoating layer 160E is determined by the overcoating layer ( The step difference alleviating layer 170E is formed to be smaller than the thickness h2 of the step difference alleviating layer 170E formed on the second connection portion 164E of the 160E).

Referring to FIG. 1E , the step difference alleviating layer 170E is formed so that its top surface is a non-planarized surface. That is, the upper surface portion of the step difference alleviating layer 170E formed on the convex portion 163E of the overcoat layer 160E and the upper surface portion of the step difference alleviating layer 170E formed on the second connection portion 164E of the overcoat layer 160E. are on different planes, so that the upper surface of the step alleviation layer 170E is formed to be a non-planarized surface.

In the organic light emitting diode display 100E according to an embodiment of the present invention, the overcoat layer 160E has a plurality of convex portions 163E, and the step alleviation layer 170E includes a plurality of convex portions ( 163E) to relieve the step difference. The over-coating layer 160E and the step alleviating layer 170E form an MLA structure, and the MLA structure of the over-coating layer 160E and the step alleviating layer 170E is the over-coating layer 160A described with reference to FIGS. 1A and 1B . It may have the same function as the MLA structure of the step difference alleviating layer 170A. Also, the step alleviating layer 170E may have the same function as the step alleviating layer 170A described with reference to FIGS. 1A and 1B .

2A is a cross-sectional view illustrating an organic light emitting diode display including a plurality of truncated recesses and a filling layer according to an exemplary embodiment. FIG. 2B is an enlarged cross-sectional view of region X of FIG. 2A . 2A and 2B , the organic light emitting diode display 200 includes a substrate 210 , a thin film transistor 220 , a color filter 250 , an overcoat layer 260 , a filling layer 270 , and an organic light emitting device ( 240). The organic light emitting diode display 200 of FIGS. 2A and 2B has a different shape than the organic light emitting display device 100A of FIGS. 1A and 1B , only that the shape of the overcoat layer 260 is different and the filling layer 270 is employed. This is only different, and since other configurations are substantially the same, redundant description is omitted.

An overcoat layer 260 is formed on the color filter 250 and the passivation layer 233 . The overcoat layer 260 includes a plurality of concave portions 261 having a cut-off shape formed to overlap the color filter 250 . Since the concave portion 261 having a plurality of hem cut-off shapes has a hemispherical or semi-ellipsoidal shape with a cut hem, the side surface of the concave portion 261 having a plurality of hem cut off is an inclined curved surface, and the plurality of hem is cut off Each of the concave portions 261 of , exposes the color filter 250 . The overcoat layer 260 functions as a planarization layer in a portion where the concave portions 261 having the shape of a plurality of cut ends are not formed.

A filling layer 270 is formed on the overcoat layer 260 . The filling layer 270 is formed of a material having a refractive index greater than that of the overcoat layer 260 . The refractive index of the filling layer 270 may be about 1.7 to 2.0. Specifically, the filling layer 270 is a layer in which nanoparticles having a size of several tens of nm, such as _{titanium oxide (TiO 2} ), zirconium oxide (ZrO ₂ ), etc. having a refractive index greater than that of the polymer binder are dispersed in a polymer binder, or a photo A layer in which nanoparticles such as _{titanium oxide (TiO 2} ), zirconium oxide (ZrO ₂ ), etc. having a refractive index greater than that of the resist are dispersed in the photoresist.

The filling layer 270 fills at least a portion of the inside of the concave portion 261 having a shape in which the lower end of the overcoat layer 260 is cut off. That the filling layer 270 fills at least a portion of the inside of the concave portion 261 having the truncated bottom means that the filling layer 270 is the concave portion 261 having the truncated hem as shown in FIG. 2B . This means that only a part of the interior may be filled, or the filling layer 270 may fill the entire interior of the concave portion 261 having a cut-off shape. As shown in FIG. 2B , when the filling layer 270 fills only a part of the inside of the concave portion 261 having the truncated hem, the filling layer 270 is the lower portion of the concave portion 261 having the truncated hem. The filling layer 270 is formed to have an embossed structure by filling only a portion of the space of the concave portion 261 having the shape cut from the bottom.

In the organic light emitting diode display 200 according to an embodiment of the present invention, the overcoat layer 260 includes a plurality of concave portions 261 having cut ends, and the concave portions 261 having a plurality of cut ends. exposes the color filter 250 . Accordingly, a portion filling the concave portions 261 having a shape in which a plurality of ends of the overcoating layer 260 are cut out of the filling layer 270 formed on the overcoating layer 260 is in contact with the overcoating layer 260 or a color It is in contact with the filter 250 . When the light emitted from the organic light emitting layer 242 travels to the surface where the filling layer 270 and the overcoating layer 260 are in contact, the interface between the overcoating layer 160A and the step alleviation layer 170A described in FIGS. 1A and 1B . The light emitted from the organic light emitting layer 242 proceeds in the same manner as the light proceeds in . On the other hand, when the light emitted from the organic light emitting layer 242 travels to the surface where the filling layer 270 and the color filter 250 are in contact, the refractive index of the filling layer 270 is greater than the refractive index of the color filter 250, The light emitted from the organic light emitting layer 242 may be totally reflected at a surface in which the filling layer 270 and the color filter 250 contact each other. Accordingly, light that is totally reflected from the surface where the filling layer 270 and the color filter 250 come into contact and travels toward the cathode 243 is reflected from the cathode 243 and travels to the filling layer 270 again, so the light can be recycled. Then, the light emitted from the organic light emitting layer 242 passes through the MLA structure of the filling layer 270 and the overcoat layer 260 again, and the light propagates at an incident angle smaller than the total reflection critical angle at the interface between the substrate 210 and air. can be changed to Accordingly, light extraction efficiency for light trapped inside the organic light emitting diode display 200 in the substrate mode may be improved.

2A and 2B, the filling layer 270 is shown to be formed to have an embossed structure, but the filling layer 270 fills all of the inside of the concave portion 261 having a plurality of ends cut off, and over The upper portion of the coating layer 260 may be planarized.

3 is a flowchart illustrating a method of manufacturing an organic light emitting diode display including an overcoat layer including a plurality of recesses and a step alleviation layer according to an exemplary embodiment of the present invention. 4A to 4F are cross-sectional views illustrating a method of manufacturing an organic light emitting diode display including an overcoat layer including a plurality of recesses and a step alleviation layer according to an exemplary embodiment of the present invention. In FIGS. 4A to 4F , a portion corresponding to a thin film transistor among various elements of the organic light emitting diode display 400 is not shown, and a portion overlapping a portion on which the color filter 450 is formed in the organic light emitting display apparatus 400 is mainly focused. shown. Also, the organic light emitting display device 400 of FIG. 4F is substantially the same as the organic light emitting display device 100A of FIG. 1B .

First, a color filter 450 is formed on the substrate 410 ( S30 ). For a more detailed description of forming the color filter 450 on the substrate 410 , refer to FIG. 4C .

Referring to FIG. 4C , a color filter 450 is formed on a substrate 410 . In more detail, the color filter 450 is formed on the passivation layer 433 on the substrate 410 .

In some embodiments, an air gap 480 may be formed between the substrate 410 and the color filter 450 . For a more detailed description of forming the air gap 480 , reference is made together to FIGS. 4A and 4B .

Referring to FIG. 4A , before the color filter 450 is formed on the substrate 410 to form the air gap 480 , a sacrificial layer that is thermally decomposed between the substrate 410 and the color filter 450 . (481) can be formed. Specifically, the sacrificial layer 481 is formed between the passivation layer 433 and the color filter 450 . The sacrificial layer 481 is a layer formed of a material that is decomposed during heat treatment, and may be formed of various materials that are decomposed and removed by heat.

4A and 4B , after the sacrificial layer 481 is formed, a color filter 450 may be formed on the sacrificial layer 481 , and after the color filter 450 is formed, the sacrificial layer 481 . The sacrificial layer 481 may be decomposed by heat-treating , thereby forming an air gap 480 between the substrate 410 and the color filter 450 .

Next, an overcoat layer 460 including a plurality of concave portions 461 overlapping the color filter 450 is formed on the color filter 450 ( S31 ). For a more detailed description of forming the overcoat layer 460 including the plurality of recesses 461 , refer to FIGS. 4C and 4D .

Referring to FIG. 4C , a photoresist material 469 is applied on the color filter 450 to form an overcoat layer 460 . As the photoresist, both a negative type photoresist and a positive type photoresist may be used. However, in order to make the recess 461 in the overcoat layer 460 , using a negative type photoresist is a manufacturing process. is advantageous A photolithography process is performed on the overcoat layer 460 to form a plurality of concave portions 461 of the overcoat layer 460 as shown in FIG. 4D . The plurality of concave portions 461 may be formed only in the overcoat layer 460 overlapping the color filter 450 .

In some embodiments, the overcoat layer 460 may be formed in the same shape as the overcoat layer 260 illustrated in FIG. 2A by adjusting the exposure amount during the above-described photolithography process. For example, by increasing the exposure amount, the amount of the photoresist material 469 that is patterned and subsequently removed can be increased, so that the overcoat layer 460 is truncated as shown in FIG. 2A , as shown in FIG. 2A . It may be formed to have a concave portion 261 of a shape.

In this case, in order to form the concave portion 461 of the overcoat layer 460 , photoresist is applied, patterned into a concave shape through a photolithography process, and then heat treatment is performed. In this case, the shape of the concave portion 461 of the overcoat layer 460 may be formed by performing the heat treatment step by step over two steps, rather than performing the heat treatment all at once. For example, before performing the final heat treatment in the vicinity of about 200ºC or more and 250 ºC or less, the intermediate heat treatment at about 100ºC or more and 130ºC or less should be performed first. The aspect ratio of the concave portion 461 of the overcoat layer 460 may be adjusted by adjusting the temperature and the execution time in the intermediate heat treatment process. However, the method of adjusting the intermediate heat treatment temperature and the execution time proposed as a method for making the aspect ratio of the concave portion 461 of the overcoat layer 460 have a value of 0.25 or more and 0.6 or less is only an example, and patterning in the photolithography process It is also possible by a method of controlling the amount of UV exposure at the time, but is not limited thereto.

4C and 4D show that the overcoat layer 460 is formed of photoresist for convenience of explanation, but the present invention is not limited thereto, and the overcoat layer 460 may be formed of various insulating materials having a refractive index of about 1.5. In addition, the plurality of concave portions 461 of the overcoat layer 460 may be formed through a photolithography process for various insulating materials.

In FIGS. 4C and 4D , it has been described that the plurality of concave portions 461 are formed in the overcoat layer 460 , but as shown in FIGS. 2A and 2B , the overcoat layer 460 includes the plurality of convex portions 263 . It may be formed to have In order to form the plurality of convex portions 263 on the overcoat layer 460 , a photoresist material 469 may be coated on the color filter 450 as shown in FIG. 4C , and a photolithography process may be performed. .

In some embodiments, before forming the color filter 450 , an insulating layer having a refractive index smaller than the refractive index of the overcoat layer 460 and the refractive index of the color filter 450 layer is formed between the substrate 410 and the color filter 450 . can be formed The insulating layer may be formed at the same position as the air gap 480 illustrated in FIG. 4B .

Next, a step difference alleviating layer 470 having a refractive index greater than that of the overcoating layer 460 and for alleviating the step difference due to the concave portion 461 is formed on the overcoating layer 460 ( S32 ). For a more detailed description of forming the step alleviation layer 470 , refer to FIG. 4E .

Referring to FIG. 4E , a spin coating method may be used to form the step alleviation layer 470 . That is, the formation of the step alleviation layer 470 includes spin-coating a polymer binder or phorotest in which nanoparticles are dispersed. During spin coating, the spin coating speed and the viscosity of the polymer binder or photoresist may be adjusted to control the thickness and non-planarity of the step alleviation layer 470 . For example, when the spin coating rate is increased and the viscosity of the polymer binder or photoresist is lowered, compared with the case of lowering the spin coating rate and increasing the viscosity of the polymer binder or photoresist formed on the concave portion 461 . The thickness of the step alleviation layer 470 may be relatively low, and the non-planarity may be relatively high. In the method of manufacturing an organic light emitting display device according to an embodiment of the present invention, the thickness of the step difference alleviating layer 470 formed on the concave portion 461 of the overcoating layer 460 is determined by the thickness of the first connecting portion 462 of the overcoating layer 460 . The spin coating speed or the viscosity of the polymer binder or photoresist may be adjusted to be greater than the thickness of the step alleviation layer 470 formed thereon.

Although not shown in FIG. 4E , as shown in FIG. 2 , even when the over-coating layer 460 has a plurality of convex portions, the thickness of the step alleviation layer 470 formed on the convex portions of the over-coating layer 460 is over The spin coating speed or the viscosity of the polymer binder or the photoresist may be adjusted to be smaller than the thickness of the step alleviation layer 470 formed on the second connection portion of the coating layer 460 .

Although it has been described that the spin coating method is used to form the step alleviation layer 470 in FIG. 4E, photolithography, slit coating, ink jet printing, dip coating, and nozzle printing Various wet coating methods such as nozzle printing and screen printing may also be used.

Next, an anode 441 , an organic emission layer 442 , and a cathode 443 are sequentially stacked on the step alleviation layer 470 to form an organic light emitting diode 440 ( S33 ). For a more detailed description of forming the organic light emitting device 440 , refer to FIG. 4E .

Referring to FIG. 4E , an anode 441 is formed along the shape of the step alleviation layer 470, and the organic light emitting layer 442 is formed on the anode 441 along the shape of the anode 441, and the organic light emitting layer ( On the 442 , a cathode 443 is formed along the shape of the organic light emitting layer 442 .

In some embodiments, when the concave portion 461 of the over-coating layer 460 can be formed so that the aspect ratio of the concave portion 461 of the over-coating layer 460 has a value of 0.25 or more and 0.6 or less, the step difference mitigating layer An anode 441 having a shape following the gentle morphology of the concave portion 461 of the overcoat layer 460 is formed on the overcoat layer 461 without going through the step S32 of forming, and on the anode 441 An organic light emitting layer 442 having a shape of the anode 441 is formed thereon, and a cathode 443 having a shape of the organic light emitting layer 442 is formed on the organic light emitting layer 442 . At this time, prior to forming the anode 441, a second passivation layer (not shown) with a thickness of tens to hundreds of nanometers having the same or similar refractive index as that of the anode 141A may be formed on the overcoat layer 460 . have. When the second passivation layer (not shown) is formed on the overcoat layer 160A by deposition, the second passivation layer (not shown) has a shape following the gentle morphology of the recessed portion 161A of the overcoat layer 160A. this is formed

By applying the overcoat layer and the step difference mitigating layer of the present invention, the organic light emitting diode display according to an embodiment of the present invention secures the light extraction efficiency of the same or improved level compared to Comparative Example 1, so that the driving voltage is increased For a more detailed description of the low current efficiency and excellent power efficiency, see Table 1 together.

drive voltage cd/A lm/W Comparative Example 1 12.8 66 16 Organic light emitting display device according to an embodiment of the present invention 10.9 93 27

In Table 1, the organic light emitting diode display according to Comparative Example 1 and the exemplary embodiment of the present invention is a white organic light emitting device designed by stacking two organic light emitting layers. In this case, one of the two organic light-emitting layers is an organic light-emitting layer that emits blue light, and the other is an organic light-emitting layer that emits yellow-green light. These two organic light emitting layers are stacked.

In Table 1, the organic light emitting diode display according to an exemplary embodiment of the present invention has a structure in which a substrate, an overcoat layer, a step reduction alleviating layer, an anode, an organic light emitting layer, and a cathode are stacked from the bottom. At this time, specifically, the organic light emitting layer is a 50 nm charge injection or transport layer from the bottom, an organic light emitting layer emitting yellow-green light of 20 nm, a charge injection or transport layer of 90 nm, an organic light emitting layer emitting blue light of 20 nm, 180 nm has a stacked structure of charge injection and transport layers. In this case, the overcoat layer and the step difference alleviation layer refer to the overcoat layer and the step difference alleviation layer of the present invention. In this case, the charge injection or transport layers may be a hole injection layer, a hole transport layer, a charge generation layer, an electron injection layer, an electron transport layer, or the like.

In Table 1, Comparative Example 1 has the same structure as the organic light emitting diode display according to the exemplary embodiment, except that the overcoat layer and the step difference mitigating layer of the present invention are not applied. A light emitting layer was used. In other words, the organic light emitting diode display according to an embodiment of the present invention is different from Comparative Example 1 in that the overcoat layer and the step difference mitigating layer of the present invention are applied.

In Table 1, although the organic light emitting layers of Comparative Example 1 and the organic light emitting diode display according to an embodiment of the present invention have the same thickness as each other, the driving voltage V of the organic light emitting display device according to the embodiment of the present invention is It is lower than the driving voltage of Comparative Example 1 by 1.9 V. As a result, the current efficiency (cd/A) and the power efficiency (lm/W) of the organic light emitting diode display according to the embodiment of the present invention are increased by 40% and 65%, respectively, than the current efficiency and power efficiency of Comparative Example 1.

By applying the overcoat layer and the step difference mitigating layer of the present invention, the organic light emitting display device according to an embodiment of the present invention secures the same or improved light extraction efficiency as compared to Comparative Example 1, and the thickness of the organic light emitting layer is reduced. See also Table 2 for a more detailed description of what can be reduced.

drive voltage cd/A lm/W Comparative Example 1 12.8 66 16 Organic light emitting display device according to an embodiment of the present invention 7.8 97 39

In Table 2, the organic light emitting diode display according to Comparative Example 1 and the exemplary embodiment of the present invention is a white organic light emitting device designed by stacking two organic light emitting layers. In this case, one of the two organic light-emitting layers is an organic light-emitting layer that emits blue light, and the other is an organic light-emitting layer that emits yellow-green light. These two organic light emitting layers are stacked.

In Table 2, the organic light emitting diode display according to an embodiment of the present invention has a structure in which a substrate, an overcoat layer, a step difference alleviating layer, an anode, an organic light emitting layer, and a cathode are stacked from the bottom. In this case, the organic light emitting layer specifically includes a charge injection or transport layer of 50 nm from the bottom, an organic light emitting layer that emits yellow-green light of 20 nm, a charge injection or transport layer of 70 nm, an organic light emitting layer that emits blue light of 20 nm, 70 nm has a stacked charge injection or transport layer of In this case, the overcoat layer and the step difference alleviation layer refer to the overcoat layer and the step difference alleviation layer of the present invention. In this case, the charge injection or transport layers may be a hole injection layer, a hole transport layer, a charge generation layer, an electron injection layer, an electron transport layer, or the like.

In Table 2, in the organic light emitting diode display according to an exemplary embodiment of the present invention, the organic light emitting layer emitting blue light, the organic light emitting layer emitting yellow-green light, and the charge injection and transport layers all have a thickness of less than 100 nm. Alternatively, each of the layers constituting the organic light emitting layer of the organic light emitting diode display according to the exemplary embodiment has a thickness of less than 100 nm.

In Table 2, in Comparative Example 1, the overcoat layer and the step alleviation layer of the present invention were not applied, and the charge transport or injection layers in the organic light emitting diode display according to the embodiment of the present invention have a thickness thinner than the thickness of the charge, transport or injection layers. Except for this, Comparative Example 1 and the organic light emitting display device according to an embodiment of the present invention have the same structure.

In Table 2, the driving voltage V of the organic light emitting diode display according to an exemplary embodiment, which has a thickness that is about 36% thinner than that of the organic light emitting layer of Comparative Example 1, is 5 V higher than the driving voltage of Comparative Example 1. low. Accordingly, the current efficiency and power efficiency of the organic light emitting diode display according to the exemplary embodiment of the present invention are increased by 47% and 140%, respectively, than the current efficiency and power efficiency of Comparative Example 1.

That is, by applying the overcoat layer and the step difference alleviating layer of the present invention, the thickness of the organic light emitting layer can be remarkably reduced and the light extraction efficiency can be improved. As a result, it is possible to ultimately obtain better effects in terms of reduction of driving voltage and power consumption, current efficiency, and power efficiency.

Hereinafter, various features of the organic light emitting diode display including the overcoat layer including a plurality of recesses and the step alleviation layer according to an exemplary embodiment of the present invention will be described.

According to another feature of the present invention, the organic light emitting layer is characterized in that it has a thickness of 350 nm or less.

According to another feature of the present invention, the organic light emitting display device is characterized in that the organic light emitting layer further includes charge injection and transport layers, and all of the charge injection and transport layers have a thickness of less than 100 nm.

According to another feature of the present invention, the upper surface of the step difference alleviating layer is characterized in that it is a non-planar surface.

According to another feature of the present invention, the overcoat layer is characterized in that it includes a first connection portion connecting each of the concave portions or a second connection portion connecting each of the convex portions.

According to another feature of the present invention, when the overcoat layer includes the first connecting portion, the thickness of the step alleviating layer disposed on the concave portion is greater than the thickness of the step alleviating layer disposed on the first connecting portion. .

According to another feature of the present invention, when the overcoat layer includes the second connecting portion, the thickness of the step alleviating layer disposed on the convex portion is smaller than the thickness of the step alleviating layer disposed on the second connecting portion. .

According to another feature of the present invention, the anode, the organic light emitting layer, and the cathode are arranged along the shape of the upper surface of the step difference alleviating layer, and it is characterized in that it has a non-planarized upper surface and a lower surface.

According to another feature of the present invention, one of the convex portion or the concave portion is characterized in that it has a hemispherical shape or a semi-ellipsoidal shape.

According to another feature of the present invention, it is characterized in that the aspect ratio of the cathode disposed on the convex portion or the concave portion is 0.5 to 0.7.

According to another feature of the present invention, each of the hemispherical shape and the semi-ellipsoidal shape has a diameter of 1 to 5 μm, and a height of 1 to 4 μm.

According to another feature of the present invention, the diameter of the hemispherical shape is greater than or equal to the distance between the centers of the hemispherical shapes adjacent to each other, and the diameter of the hemispherical shape is greater than or equal to the distance between the centers of the adjacent hemispherical shapes. characterized in that

According to another feature of the present invention, the organic light emitting layer is arranged in a structure in which a plurality of organic light emitting layers are stacked to emit white light, and the plurality of organic light emitting layers include a blue organic light emitting layer.

According to another feature of the present invention, the step difference alleviating layer has a refractive index of 1.7 to 2.0.

According to another feature of the present invention, the step difference alleviating layer is a layer in which nanoparticles having a refractive index greater than that of the polymer binder and the photoresist are dispersed in a polymer binder or photoresist.

According to still another feature of the present invention, the organic light emitting diode display further includes an insulating layer disposed between the substrate and the color filter, the insulating layer having a refractive index smaller than that of the overcoat layer and the refractive index of the color filter.

According to another feature of the present invention, the insulating layer is characterized in that it is made of a fluorinated polymer having a refractive index of 1.3 to 1.4.

According to another feature of the present invention, the organic light emitting diode display further includes an air gap disposed between the substrate and the color filter.

Hereinafter, various features of the organic light emitting diode display including a plurality of truncated recesses and a filling layer according to an exemplary embodiment of the present invention will be described.

According to another feature of the present invention, the filling layer is a layer for planarizing an upper portion of the overcoat layer.

According to another feature of the present invention, the filling layer is characterized in that it is arranged to have an embossing structure by filling only a partial space of the recess from the lower part of the recess.

Hereinafter, various features of a method of manufacturing an organic light emitting diode display including an overcoat layer including a plurality of recesses and a step alleviation layer according to an exemplary embodiment of the present invention will be described.

According to another aspect of the present invention, the step of forming the overcoat layer includes applying a photoresist material on a color filter and forming a plurality of convex portions or a plurality of concave portions of the overcoat layer through a photolithography process. characterized in that

According to another feature of the present invention, the step of forming the step alleviation layer is characterized in that it includes the step of spin-coating a polymer binder or photoresist in which nanoparticles are dispersed.

According to another feature of the present invention, the step of spin coating comprises adjusting the thickness of the step difference alleviating layer by controlling the spin coating speed and the viscosity of the polymer binder or photoresist.

According to another feature of the present invention, the forming of the organic light emitting device includes: forming an anode along the shape of the step difference alleviating layer; forming an organic light emitting layer on the anode along the shape of the anode; and the organic light emitting layer on the organic light emitting layer It characterized in that it comprises the step of forming a cathode along the shape of.

According to another feature of the present invention, the method of manufacturing an organic light emitting display device further comprises forming an insulating layer having a refractive index smaller than that of the overcoat layer and the refractive index of the color filter layer between the substrate and the color filter. .

According to another aspect of the present invention, a method of manufacturing an organic light emitting display device includes: forming a sacrificial layer that is decomposed by heat between a substrate and a color filter; and heat-treating the sacrificial layer to form an air gap between the substrate and the color filter. It is characterized in that it further comprises.

Hereinafter, various features of the organic light emitting diode display according to an exemplary embodiment will be described.

According to another feature of the present invention, the organic light emitting display device further includes a second passivation layer disposed between the overcoat layer and the organic light emitting layer, wherein the second passivation layer is made of an insulating inorganic material, and The refractive index has a value closer to the refractive index of the anode than the refractive index of the overcoat layer, and the second passivation layer is characterized in that it has a shape following the gentle morphology of the recesses of the overcoat layer.

Although the embodiments of the present invention have been described in more detail with reference to the accompanying drawings, the present invention is not necessarily limited to these embodiments, and various modifications may be made within the scope without departing from the technical spirit of the present invention. . Therefore, the embodiments disclosed in the present invention are not intended to limit the technical spirit of the present invention, but to explain, and the scope of the technical spirit of the present invention is not limited by these embodiments. The protection scope of the present invention should be construed by the following claims, and all technical ideas within the equivalent range should be construed as being included in the scope of the present invention.

110A, 110C, 110D, 110E, 210, 410: substrate
120A, 120C, 120D, 120E, 212, 420: thin film transistor
121A, 121C, 121D, 121E, 221, 421: gate electrode
122A, 122C, 122D, 122E, 222, 422: active layer
123A, 123C, 123D, 123E, 223, 423: source electrode
124A, 124C, 124D, 124E, 224, 424: drain electrode
131A, 131C, 131D, 131E, 231, 431: gate insulating layer
132A, 132C, 132D, 132E, 232, 432: Etch stopper
133A, 133C, 133D, 133E, 233, 433: passivation layer
134D: insulating layer
136A, 136C, 136D, 136E, 236, 436: Bank
140A, 140C, 140D, 140E, 240, 440: organic light emitting device
141A, 141C, 141D, 141E, 241, 441: anode
142A, 142C, 142D, 142E, 242, 442: organic light emitting layer
143A, 143C, 143D, 143E, 243, 443: cathode
150A, 150C, 150D, 150E, 250, 450: color filter
160A, 160C, 160D, 160E, 260, 460: overcoat layer
161A, 161C, 161D, 461: recesses
261: concave shape with a cut hem
162A, 162C, 162D, 462: first connection part
163E: convex
164E: second connection part
469: photoresist material
170A, 170C, 170D, 170E, 470: Step relief layer
270: filling layer
480: air gap
481: sacrificial layer
100A, 100C, 100D, 100E, 210, 410: organic light emitting diode display

Claims (30)

Board;
a color filter disposed on the substrate;
an overcoat layer disposed on the color filter and overlapping the color filter, the overcoat layer including a plurality of convex portions or a plurality of concave portions having an aspect ratio of 0.25 or more and 0.6 or less;
an insulating layer disposed between the substrate and the color filter and having a refractive index smaller than a refractive index of the overcoat layer and a refractive index of the color filter;
a step difference alleviating layer disposed on the over-coating layer, having a refractive index greater than that of the over-coating layer, and for alleviating a step difference caused by the convex portion or the concave portion; and
and an organic light emitting device disposed on the step alleviation layer and comprising an anode, an organic light emitting layer disposed on the anode, and a cathode disposed on the organic light emitting layer. delete delete According to claim 1,
The organic light emitting display device, characterized in that the top surface of the step difference mitigating layer is a non-planar surface. 5. The method of claim 4,
The organic light emitting display device of claim 1, wherein the overcoat layer includes a first connection part connecting each of the concave parts or a second connection part connecting each of the convex parts. 6. The method of claim 5,
When the overcoat layer includes the first connection part, the thickness of the step difference alleviating layer disposed on the concave part is greater than the thickness of the step difference alleviating layer disposed on the first connection part;
When the overcoat layer includes the second connection part, the thickness of the step difference alleviating layer disposed on the convex part is smaller than the thickness of the step difference alleviating layer disposed on the second connection part, display device. delete 5. The method of claim 4,
and the anode, the organic light emitting layer, and the cathode are disposed along a shape of a top surface of the step difference alleviating layer, and have a non-planar top and bottom surface. According to claim 1,
one of the convex portion or the concave portion has a hemispherical shape or a semi-ellipsoidal shape,
An aspect ratio of the cathode disposed on the convex portion or the concave portion is 0.5 to 0.7. delete delete 10. The method of claim 9,
The diameter of the hemispherical shape is greater than or equal to the distance between the centers of the hemispherical shape adjacent to each other,
and a diameter of the semi-ellipsoid shape is greater than or equal to a distance between centers of the semi-ellipsoid shape adjacent to each other. delete According to claim 1,
The organic light emitting display device, characterized in that the refractive index of the step difference alleviating layer is 1.7 to 2.0. According to claim 1,
The step difference mitigating layer is a layer in which nanoparticles having a refractive index greater than that of the polymer binder and the photoresist are dispersed in a polymer binder or photoresist. delete According to claim 1,
and the insulating layer is made of a fluorinated polymer having a refractive index of 1.3 to 1.4. According to claim 1,
The organic light emitting display device of claim 1, further comprising an air gap disposed between the substrate and the color filter. Board;
a color filter disposed on the substrate;
an overcoat layer disposed on the color filter, disposed to overlap the color filter, exposing the color filter, and including a plurality of truncated recesses having an aspect ratio of 0.25 or more and 0.6 or less;
an insulating layer disposed between the substrate and the color filter and having a refractive index smaller than a refractive index of the overcoat layer and a refractive index of the color filter; and
a filling layer disposed on the over-coating layer, having a refractive index greater than that of the over-coating layer, and filling at least a portion of the inside of the concave portion;
an organic light emitting device disposed on the filling layer and including an anode, an organic light emitting layer disposed on the anode, and a cathode disposed on the organic light emitting layer,
The organic light emitting display device, characterized in that a side surface of the concave portion is an inclined curved surface. 20. The method of claim 19,
The filling layer is a layer that planarizes an upper portion of the overcoat layer. 20. The method of claim 19,
and the filling layer is disposed to have an embossed structure by filling only a partial space of the recessed portion from a lower portion of the recessed portion. forming an insulating layer on the substrate;
forming a color filter on the insulating layer;
forming an overcoat layer overlapping the color filter on the insulating layer and the color filter and including a plurality of convex portions or a plurality of concave portions having an aspect ratio of 0.25 or more and 0.6 or less;
forming a step difference alleviating layer on the overcoat layer having a refractive index greater than that of the overcoat layer and for alleviating a step difference caused by the convex portion or the concave portion; and
and sequentially stacking an anode, an organic light emitting layer, and a cathode on the step difference alleviating layer to form an organic light emitting device,
The method of claim 1, wherein the insulating layer has a refractive index smaller than a refractive index of the overcoat layer and a refractive index of the color filter. 23. The method of claim 22,
The step of forming the overcoat layer,
applying a photoresist material on the color filter; and
and forming the plurality of convex portions or the plurality of concave portions of the overcoat layer through a photolithography process. 23. The method of claim 22,
The step of forming the step alleviation layer includes spin coating a polymer binder or photoresist in which nanoparticles are dispersed,
The method of claim 1 , wherein the spin coating includes adjusting a thickness of the step difference alleviating layer by adjusting a spin coating speed and a viscosity of the polymer binder or the photoresist. delete delete delete 23. The method of claim 22,
forming a sacrificial layer decomposed by heat between the substrate and the color filter; and
and forming an air gap between the substrate and the color filter by heat-treating the sacrificial layer. Board;
a color filter disposed on the substrate;
an overcoat layer disposed on the color filter and overlapping the color filter and including a plurality of convex portions or a plurality of concave portions having an aspect ratio of 0.25 or more and 0.6 or less;
an insulating layer disposed between the substrate and the color filter and having a refractive index smaller than a refractive index of the overcoat layer and a refractive index of the color filter; and
an organic light emitting device disposed on the overcoat layer and including an anode, an organic light emitting layer disposed on the anode, and a cathode disposed on the organic light emitting layer,
The organic light emitting device is disposed on a non-flat screen having an aspect ratio of 0.25 or more and 0.6 or less, and the anode, the organic light emitting layer and the cathode have a shape that follows the morphology of the non-planar screen. luminescent display. 30. The method of claim 29,
Further comprising a second passivation layer disposed between the overcoat layer and the organic light emitting layer,
The second passivation layer is made of an insulating inorganic material,
The refractive index of the second passivation layer has a value closer to the refractive index of the anode than the refractive index of the overcoat layer,
and the second passivation layer has a shape following a gentle morphology of the concave portion of the overcoat layer.

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