KR20080061675A - Organic light emitting device and manufacturing method thereof - Google Patents

Abstract

The present invention is to provide an organic light emitting device that emits light (top emitting) to the front surface suitable for improving color purity and brightness using a micro cavity, and a method of manufacturing the same, according to an embodiment for achieving the above object The organic light emitting device includes: a TFT array substrate having a TFT array and first, second, and third sub pixel regions defined therein; First, second and third anode electrodes respectively formed in the first to third sub pixel regions of the TFT array substrate; First, second and third transparent electrodes configured to contact the first, second and third anode electrodes, respectively; An organic material layer including first, second, and third light emitting layers each having first, second, and third colors corresponding to the first to third sub-pixel areas; An organic insulating layer having different thicknesses under the first, second, and third light emitting layers; A cathode electrode formed on the organic material layer; It characterized in that it comprises an encap substrate which is opposed to the TFT array substrate and bonded. In this case, the first, second, and third light emitting layers are B, G, and R color light emitting layers, respectively.

Description

Organic Light Emitting Device and method for fabricating the same

1 is a circuit diagram of a flat panel display device having a general AMOLED

2 is a schematic cross-sectional view of a general organic light emitting device

3 is a cross-sectional view illustrating a structure of an organic light emitting device having a top emitting method according to the present invention.

4 is a structural cross-sectional view of an organic light emitting diode according to a first exemplary embodiment of the present invention.

5A to 5E are cross-sectional views illustrating a method of manufacturing the organic light emitting diode according to the first embodiment of the present invention.

6 is a structural cross-sectional view of an organic light emitting diode according to a second exemplary embodiment of the present invention.

7A to 7E are cross-sectional views illustrating a method of manufacturing an organic light emitting diode according to a second exemplary embodiment of the present invention.

Explanation of symbols on the main parts of the drawings

51, 71: TFT array substrate 52a, 72a: first anode electrode

52b, 72b: second anode electrode 52c, 72c: third anode electrode

53 and 73: organic insulating films 54a and 74a: first contact hole

54b and 74b: second contact hole 55a and 75a: first transparent electrode

55b, 75b: second transparent electrode 55c, 75c: third transparent electrode

56, 76: bank film 57: hole injection layer

58: hole transport layer 77: organic material layer

59a, 59b, 59c: first, second and third light emitting layers

60: electron transport layer 61: electron injection layer

62, 78: cathode electrode 65, 90: encap substrate

91: black matrix

92a, 92b, 92c: first, second and third color filter layers

The present invention relates to an organic light emitting device, and more particularly, to a light emitting organic light emitting device suitable for improving color purity and brightness, and a method of manufacturing the same.

Currently, a cathode ray tube (CRT) is used as a main device in a display device such as a television or a monitor, but this has a problem of weight and volume and high driving voltage. Accordingly, there is a need for a flat panel display having excellent characteristics such as thinness, light weight, and low power consumption, and has emerged, such as a liquid crystal display, a plasma display panel, and an electric field emission. Various flat panel displays such as field emission displays and electroluminescent displays (or electroluminescence displays (ELDs)) have been researched and developed.

Among the flat panel display devices, the electroluminescent display device uses an electro luminescence (EL) phenomenon in which light is generated when a certain amount of electric field is applied to a phosphor, and an inorganic electroluminescent device depending on a source causing excitation of carriers. And organic electroluminescent devices (organic electroluminescence display: OELD or organic ELD).

Among them, the organic electroluminescent device is attracting attention as a natural color display device because it emits light in all regions of visible light including blue, and has high luminance and low operating voltage characteristics. In addition, because of self-luminous, the contrast ratio is high, the ultra-thin display can be realized, and the process is simple, so that environmental pollution is relatively low. On the other hand, it is easy to implement a moving picture with a response time of several microsec, there is no limitation of viewing angle, it is stable even at low temperature, and it is easy to manufacture and design a driving circuit because it is driven at a low voltage of DC 5V to 15V.

The organic electroluminescent device has a structure similar to that of an inorganic electroluminescent device, but the light emitting principle is called organic light emitting diode (OLED) because the light emission is made by recombination of electrons and holes.

In addition, the flat panel display has an active matrix form in which a plurality of pixels are arranged in a matrix form and a thin film transistor is connected to each pixel. The active matrix organic light emitting diode (LED) is applied to the organic light emitting diode. Active Matrix Organic Light Emitting Device (AM-OLED) will be described with reference to the accompanying drawings.

FIG. 1 is a circuit diagram of a flat panel display device having a typical AM-OLED, and FIG.

As shown in FIG. 1, a typical AM-OLED includes a data driving circuit 20, a scan line driving circuit 22, a plurality of scan lines S1, S2,..., Sn and data lines D1 and D2. The organic EL display panel 24 includes a switching PMOS transistor P1, a capacitor C2, a current driving PMOS transistor P2, and an organic EL (OEL) between each of the ..., Dn. .

The gate of the PMOS transistor P1 is connected to the scan line and the source is connected to the data line. One side of the capacitor C2 is connected to the drain of the PMOS transistor P1, and the other side thereof is connected to the voltage Vdd. The gate of the PMOS transistor P2 is connected to the drain of the PMOS transistor P1. The anode of the organic EL (OEL) is connected to the drain of the PMOS transistor P2, and the cathode is connected to the ground voltage.

In the AM-OLED having the above configuration, the organic EL is formed with an anode electrode 2 formed on the glass substrate 1 in a transparent electrode pattern, as shown in FIG. 2, and on the hole injection layer 3 thereon. The light emitting layer 4 and the electron injection layer 5 are stacked, and a cathode electrode 6 composed of a metal electrode is formed on the electron injection layer 5.

When a driving voltage is applied to the anode electrode 2 and the cathode electrode 6, the holes in the hole injection layer 3 and the electrons in the electron injection layer 5 proceed toward the light emitting layer 4 to excite the light emitting layer 4. This causes the light emitting layer 4 to emit visible light. Thus, an image or an image is displayed by the visible light generated from the light emitting layer 4.

As described above, the organic light emitting device induces self-emission of the organic material layer by applying a current to the organic material layer between the anode electrode and the cathode electrode.

The organic light emitting diode driven as described above may be classified into a top emitting organic light emitting element and a bottom emitting organic light emitting element according to a light emitting direction.

In general, a top emitting organic light emitting diode is a reflective electrode formed on a substrate under the light emitting layer so that light is reflected upward, and a bottom emitting organic light emitting diode is a reflective electrode on a substrate above the light emitting layer so that light is reflected downward. This is formed.

At this time, the top emitting organic light emitting device has a wider aperture ratio than the bottom emitting organic light emitting device, and thus, much research has been conducted.

In more detail, in the bottom emitting active matrix organic light emitting device, when the light emitted from the organic material layer is emitted through the lower substrate on which the TFT is formed, the light emitting surface is covered by the TFT formed between the substrate and the organic material layer. Accordingly, as the size and the number of the TFTs increase, the aperture ratio of the active matrix organic light emitting element decreases exponentially, making it difficult to use as a display element.

In order to overcome this problem, a top emitting method for emitting light to the opposite substrate facing the substrate has emerged regardless of the TFT formed on the substrate.

The manufacturing method of the active matrix organic light emitting device of the top emitting method is briefly described as follows.

First, a TFT including a gate electrode, a source electrode, and a drain electrode is formed on a substrate, and a planarization film having a via hole for exposing the source electrode and the drain electrode of the TFT is formed on the entire surface.

An anode electrode is then formed to contact the drain electrode of the TFT exposed by the via hole on the front surface.

An insulating layer is formed to cover a region where the source / drain electrode and the anode electrode contact each other, and an organic material layer and a cathode electrode are sequentially formed on the entire surface.

In the active matrix organic light emitting device of the top emitting system configured as described above, the anode electrode formed on the TFT becomes the reflecting surface, and the cathode electrode formed after the organic material is deposited thereon is composed of the transparent electrode, so that the light is emitted. .

The light emitting paths of the top emitting device are directly emitted through the cathode electrode when viewed in a large view, and are emitted through the cathode electrode, which is reflected through the anode electrode.

Therefore, in the case of such a device, the light efficiency is determined from a complex factor such as the microcavity effect, the reflectance of the reflecting surface, and the transmittance of the transparent electrode.

However, in the top emitting active matrix organic light emitting diode (AMOLED), the distortion of light emitted in the OLED device occurs due to the cavity characteristics among the above factors, thereby degrading the color purity characteristics. This can cause a problem that the luminance characteristic is lowered.

In order to improve the light efficiency by the microcavity effect of light and wave overlap, it is necessary to optimize the optical length to the light of the R, G, B light emitting layer. Therefore, there is a need for a technical proposal to solve this problem.

The present invention has been made to solve the above problems, and an object of the present invention is to provide an organic light emitting device that emits light (top emitting) to the front surface suitable for improving the emission color purity and brightness, and a manufacturing method thereof.

According to an embodiment of the present invention, an organic light emitting diode includes: a TFT array substrate having a TFT array and first, second, and third subpixel regions defined therein; First, second and third anode electrodes respectively formed in the first to third sub pixel regions of the TFT array substrate; First, second and third transparent electrodes configured to contact the first, second and third anode electrodes, respectively; An organic material layer including first, second, and third light emitting layers each having first, second, and third colors corresponding to the first to third sub-pixel areas; An organic insulating layer having different thicknesses under the first, second, and third light emitting layers; A cathode electrode formed on the organic material layer; It characterized in that it comprises an encap substrate which is opposed to the TFT array substrate and bonded.

The first, second, and third light emitting layers are B, G, and R color light emitting layers, respectively.

In the organic layer, a hole injection layer and a hole transport layer are stacked, and first, second, and third light emitting layers are formed in each of the sub-pixel regions, and electrons are formed on the upper portion including the first, second, and third light emitting layers. The transport layer and the electron injection layer are laminated.

The organic insulating film is formed in a layer between the first, second and third anode electrodes and the first, second and third transparent electrodes.

The organic insulating film is not formed in the lower region corresponding to the first light emitting layer, and is configured such that the organic insulating film under the third light emitting layer is thicker than the lower portion corresponding to the second light emitting layer.

First and second contact holes are formed in the organic insulating layer under the second and third light emitting layers to expose the first and second anode electrodes, and the first anode electrode is in direct contact with the first transparent electrode. The second and third anode electrodes are in contact with the second and third transparent electrodes through the first and second contact holes.

A bank film is further formed under the organic material layer so that the first, second and third transparent electrodes are evenly exposed.

The first, second and third anode electrodes are formed of a reflective metal, and the cathode electrode is composed of a translucent metal.

The first, second and third transparent electrodes may be formed of indium tin oxide (ITO), tin oxide (TO), indium zinc oxide (IZO), or indium tin oxide (Indium Tin). It is composed of a transparent conductive film such as Zinc Oxide (ITZO).

According to another embodiment of the present invention, an organic light emitting diode includes: a TFT array substrate having a TFT array and first, second, and third subpixel regions defined therein; First, second and third anode electrodes respectively formed in the first to third sub pixel regions of the TFT array substrate; First, second and third transparent electrodes configured to contact the first, second and third anode electrodes, respectively; A bank film formed such that one region of the first, second, and third transparent electrodes is flatly exposed; An organic material layer formed on the bank layer including the first, second and third transparent electrodes; A cathode electrode formed on the organic material layer; An encap substrate opposed to and bonded to the TFT array substrate, the encap substrate comprising a first, second and third color filter layers on top of the first, second and third sub-pixel regions; And an organic insulating layer having different thicknesses on the TFT array substrate including the first, second and third anode electrodes corresponding to the first, second and third color filter layers of the encap substrate. It features.

The first, second and third color filter layers are respectively B, G and R color filter layers.

The organic insulating layer corresponding to the first, second, and third color filter layers may have a thicker thickness of the organic insulating layer corresponding to the second color filter layer than the first color filter light layer, and may be thicker than the second color filter layer. It characterized in that the thickness of the organic insulating film corresponding to the three color filter layer is thick,

The organic material layer includes a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, and an electron injection layer.

The encap substrate further includes a black matrix in regions other than the first, second and third sub-pixel regions.

The organic insulating film is not formed in a region corresponding to the first color filter layer, and is configured such that a portion corresponding to the third color filter layer is thicker than a region corresponding to the second color filter layer.

First and second contact holes are formed in the organic insulating layer to expose the first and second anode electrodes, and the first anode electrode is in direct contact with the first transparent electrode. An anode electrode is in contact with the second and third transparent electrodes through the first and second contact holes.

In the method of manufacturing the organic light emitting device according to the embodiment of the present invention having the configuration as described above, the first, second, third anode electrode in each of the first, second, and third sub-pixel regions defined in the TFT array substrate Forming a first step; Forming an organic insulating layer on the first, second and third anode electrodes to have different thicknesses using a diffraction exposure mask; A third step of forming first, second, and third transparent electrodes to be in contact with the first, second, and third anode electrodes, respectively; Forming a bank film such that one region of the first, second, and third transparent electrodes is evenly exposed; A fifth step of forming an organic material layer on the bank layer to include first, second and third light emitting layers having first, second and third colors on the first to third sub pixel areas; A sixth step of forming a cathode on the organic material layer; And a seventh step of attaching the encap substrate to face the TFT array substrate.

Forming the hole injection layer and the hole transport layer on the entire surface of the bank layer including the first, second, and third transparent electrodes in order; Forming first, second, and third light emitting layers having first, second, and third colors, respectively, on the hole transport layer corresponding to the first, second, and third transparent electrodes by using a shadow mask. step; And sequentially forming an electron transporting layer and an electron injection layer on the hole transporting layer including the first, second, and third light emitting layers.

The first, second, and third light emitting layers are B, G, and R color light emitting layers, respectively.

According to another aspect of the present invention, there is provided a method of manufacturing an organic light emitting diode, wherein the first, second, and third anodes are respectively formed in the first, second, and third subpixel regions defined in the TFT array substrate. A first step of forming an electrode; Forming an organic insulating layer on the first, second and third anode electrodes to have different thicknesses using a diffraction exposure mask; Forming a first, second, and third transparent electrode to be in contact with the first, second, and third anode electrodes, respectively; A third step of forming a bank layer such that one region of the first, second, and third transparent electrodes is evenly exposed; A fourth step of forming an organic material layer on the bank layer including the first, second and third transparent electrodes; A fifth step of forming a cathode on the organic material layer; And attaching an encap substrate having first, second and third color filter layers on top of the first, second and third sub-pixel regions so as to face the TFT array substrate. It features.

The first, second, and third anode electrodes may be formed on the first, second, and third sub-pixel regions by selectively etching and then etching the reflective metal.

The diffraction exposure mask, which has etched the organic insulating layer, may include a transmissive region T in a region corresponding to an upper portion of the first anode electrode, and a translucent region composed of slits in an region corresponding to the upper portion of the second anode electrode. A light transmitting area is configured in an area, and a light blocking area C and a light transmitting area T are formed in an area corresponding to an upper portion of the third anode electrode.

The organic insulating layer is formed thicker on the second anode electrode than on the first anode electrode, and thicker on the third anode electrode than on the second anode electrode.

All of the organic insulating layer on the first anode electrode is removed to completely expose the first anode electrode, and the organic insulating layer on the second anode electrode is etched so that only a predetermined thickness remains, and the upper portion of the third anode electrode The organic insulating layer remains coated and first and second contact holes are formed in the second and third anode electrodes, respectively.

The bank film is formed of an organic insulating film.

The organic material layer is a method of manufacturing an organic light emitting device, characterized in that formed by depositing a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, and an electron injection layer.

The first, second and third color filter layers are respectively B, G and R color filter layers.

Prior to describing the present invention having the above characteristics, the organic light emitting device of the top emitting method for applying to the present invention which implements the microcavity effect among the factors for determining the light efficiency will be described.

3 is a cross-sectional view illustrating a structure of an organic light emitting device having a top emitting method for applying to the present invention.

As shown in FIG. 3, the organic light emitting device of the top emitting method includes a TFT array substrate 31 in which a pixel region for driving three subpixel regions as a unit is defined, and a TFT is configured for each pixel region. A single layer or two or more layers may have different thicknesses on the anode electrodes 32 respectively formed in each sub pixel region on the TFT array substrate 31 and on the anode electrode 32 of each sub pixel region. The first, second, and third transparent electrodes 33a, 33b, 33c having the laminated structure, the organic material layer 34 formed on the entire surface of the TFT and the anode electrode, and the organic material layer 34 are covered. It consists of the cathode electrode 35 formed on it.

In addition, there is an encap substrate 36 facing the TFT array substrate 31, and a black matrix layer 37 is formed in an area excluding each sub pixel region of the encap substrate 36. R, G, and B color filter layers 38c, 38b, and 38a are formed in the sub pixel region.

In the active matrix organic light emitting device of the top emitting system configured as described above, the anode electrode 32 formed on the TFT is formed as a reflective electrode, and the cathode electrode 35 is formed as a translucent electrode.

The light emitting paths of the top emitting device may be directly emitted through the cathode electrode 35 when viewed in a large view, and may be reflected through the anode electrode and exit through the cathode electrode 35 which is a translucent electrode.

As described above, in the case of the top emitting organic light emitting device, the thicknesses of the first, second, and third transparent electrodes 33a, 33b, and 33c on the anode electrode 32 constituted by the reflective electrode are varied. In addition, the microcavity effect was realized by varying the optical path length reflected by each sub-pixel region.

However, in order to configure the first, second, and third transparent electrodes on the anode electrode 32 of each sub pixel region as a single layer or a multilayer as described above, a plurality of transparent electrode materials are deposited and then etched using a photo mask. There is a problem that the process is complicated because the process to be repeated to proceed.

The present invention is to provide an active matrix organic light emitting device having a microcavity structure suitable for improving color purity and luminance by adjusting a light path length for each R, G, and B pixel area without increasing a mask.

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

First embodiment

First, the configuration of the organic light emitting device according to the first embodiment of the present invention will be described.

4 is a cross-sectional view of a structure of an organic light emitting diode according to a first exemplary embodiment of the present invention.

In the organic light emitting diode according to the first exemplary embodiment of the present invention, as illustrated in FIG. 4, a pixel region for driving three subpixel regions, namely, first, second and third subpixel regions, is defined as one unit. A TFT array substrate 51 including TFTs for each pixel region, and first, second and third anode electrodes 52a respectively configured in the first, second and third subpixel regions on the TFT array substrate 51. And 52b, 52c, and the first, second, and third anode electrodes 52a, 52b, 52c, and are formed on the entire surface of the first, second, and third anode electrodes 52a, 52b, 52c. Organic insulating films 53 configured to have different thicknesses on top of each other, and first, second, and third transparent electrodes 55a configured to contact the first, second, and third anode electrodes 52a, 52b, and 52c, respectively. And 55b and 55c, a bank film 56 formed on the entire surface of the first, second and third transparent electrodes 55a, 55b and 55c so as to expose the region flatly, and the exposed first and second 2, second A hole injection layer 57 and a hole transport layer 58 formed on the entire bank film 56 including the transparent electrodes 55a, 55b, 55c, and the first, second, and third transparent electrodes 55a, 55b. First, second and third light emitting layers 59a, 59b and 59c respectively formed on the hole transport layer 58 corresponding to 55c), and the first, second and third light emitting layers 59a, 59b and 59c. ), An electron transport layer 60 formed on the hole transport layer 58, an electron injection layer 61 formed on the electron transport layer 60, and a cathode electrode 62 formed on the electron injection layer 61. And an encap substrate 65 facing the TFT array substrate 51.

The organic light emitting diode is a top emitting active matrix organic light emitting diode, and the first, second and third anode electrodes 52a, 52b, and 52c are formed of a reflective metal, and the cathode electrode 62 is a translucent metal. Consists of.

In the above, the organic insulating film 53 configured to have a different thickness on the first, second, and third anode electrodes 52a, 52b, 52c is not formed on the first anode electrode 52a. The organic insulating film 53 on the third anode electrode 52c is thicker than the two anode electrodes 52b.

In this case, the first anode electrode 52a is in direct contact with the first transparent electrode 55a, and the first and second contact holes are formed in the organic insulating layer 53 on the second and third anode electrodes 52b and 52c. 54a and 54b are formed so that the second and third anode electrodes 52b and 52c may be connected to the second and third transparent electrodes 55b and 55c through the first and second contact holes 54a and 54b. It is in contact.

In addition, the first, second, and third transparent electrodes 55a, 55b, and 55c may include indium tin oxide (ITO), tin oxide (TO), and indium zinc oxide (IZO). ) Or a transparent conductive film such as indium tin zinc oxide (ITZO).

In the above, the hole injection layer 57, the hole transport layer 58, the first, second, and third light emitting layers 59a, 59b, 59c, the electron transport layer 60, and the electron injection layer 61 form an organic material layer.

The first, second, and third light emitting layers 59a, 59b, and 59c are B, G, and R color light emitting layers, respectively.

That is, the thicknesses of the organic insulating layers 53 under the first, second, and third light emitting layers 59a, 59b, and 59c, which are the B, G, and R color light emitting layers, are different from each other. The thickness of the organic insulating film 53 below is thick, and the thickness of the organic insulating film 53 below the third light emitting layer 59c is thicker than the second light emitting layer 59b.

As described above, the wavelength of the organic insulating film 53 in the lower region is varied according to the wavelengths of the first, second, and third light emitting layers 59a, 59b, and 59c, which are B, G, and R color light emitting layers. The optical length of was adjusted to increase the color purity and light efficiency of the emitted light.

The light emitting paths of the top emitting device are directly emitted from the first, second, and third light emitting layers 59a, 59b, and 59c through the cathode electrode 62 when viewed in a large view. In other words, the light is reflected through the third anode electrodes 52a, 52b, and 52c and comes out again through the cathode electrode 35, which is a translucent electrode.

As described above, in the case of the top emitting organic light emitting device, the color of the organic light emitting layer under the B, G, and R color light emitting layers is changed, so that the optical path lengths reflected and emitted are each color light emitting layer. The microcavity effect was realized by differently for each region.

Next, a method of manufacturing the organic light emitting device according to the first embodiment of the present invention having the above configuration will be described.

5A to 5E are cross-sectional views illustrating a method of manufacturing the organic light emitting diode according to the first embodiment of the present invention.

In the method of manufacturing the organic light emitting diode according to the first embodiment of the present invention, first, although not shown in the drawing, a pixel region for driving the first, second and third subpixel regions, which are three subpixel regions, in one unit Is defined and there is a TFT array substrate 51 in which TFTs are formed for each pixel region. In this case, the TFT of each pixel region includes a gate electrode, a source electrode, and a drain electrode, and a planarization film having via holes formed thereon so as to expose the source electrode and the drain electrode of the TFT.

5A, the reflective metal is deposited on the entire TFT array substrate 51 so as to contact the drain electrode of the TFT exposed by the via hole, and the reflective metal is deposited by a photolithography process. By selectively etching, first, second and third anode electrodes 52a, 52b and 52c are formed in the first, second and third subpixel regions, respectively.

Next, an organic insulating film 53 is coated on the TFT array substrate 51 including the first, second, and third anode electrodes 52a, 52b, 52c.

As shown in FIG. 5B, the organic insulating film 53 is selectively exposed and developed using the diffraction exposure mask 40 to form the first and second subpixel regions formed in the first, second, and third subpixel regions. The organic insulating layer 53 may have different thicknesses on the third anode electrodes 52a, 52b, and 52c.

At this time, the diffraction exposure mask 40 has a transmissive area T formed in a region corresponding to the upper portion of the first anode electrode 52a, and a translucent region composed of slits in the region corresponding to the upper portion of the second anode electrode 52b. A light transmitting region T is formed in the HT and one region, and a light blocking region C and a light transmitting region T are formed in the region corresponding to the upper portion of the third anode electrode 52c.

Therefore, all of the organic insulating film 53 on the first anode electrode 52a is removed so that the first anode electrode 52a is completely exposed, and the organic insulating film 53 on the second anode electrode 52b has only a predetermined thickness. It is removed to remain, and the organic insulating film 53 on the third anode electrode 52c remains coated. First and second contact holes 54a and 54b are formed in the second and third anode electrodes 52b and 52c, respectively. As described above, the organic insulating film 53 formed on the third anode electrode 52c is thicker than the second anode electrode 52b.

Next, as shown in FIG. 5C, a transparent conductive film is deposited on the TFT array substrate 51 including the first, second, and third anode electrodes 52a, 52b, 52c, and then transparent by a photolithography process. The conductive film is selectively etched to form first, second, and third transparent electrodes 55a, 55b, 55c in contact with the first, second, and third anode electrodes 52a, 52b, 52c.

In this case, the first anode electrode 52a is in direct contact with the first transparent electrode 55a, and the second and third anode electrodes 52b and 52c are formed through the first and second contact holes 54a and 54b. And second and third transparent electrodes 55b and 55c.

The transparent conductive film may be formed of a material such as indium tin oxide (ITO), tin oxide (TO), indium zinc oxide (IZO), or indium tin zinc oxide (ITZO). It can be configured as.

Subsequently, as shown in FIG. 5D, an insulating film is coated on the TFT array substrate 51 including the first, second, and third transparent electrodes 55a, 55b, and 55c, and then a photolithograph process. By selectively patterning the insulating film, the bank film 56 is formed so that the first, second, and third transparent electrodes 55a, 55b, 55c are flat.

At this time, the insulating film is formed of an organic insulating film.

Next, as shown in FIG. 5E, the hole injection layer 57 and the hole transport layer 58 are formed on the entire bank film 56 including the exposed first, second, and third transparent electrodes 55a, 55b, and 55c. ) In turn.

Thereafter, the first, second, and third light emitting layers 59a are individually disposed by using a shadow mask on the hole transport layer 58 corresponding to the first, second, and third transparent electrodes 55a, 55b, and 55c. , 59b, 59c), respectively. In this case, the first, second, and third light emitting layers 59a, 59b, and 59c are B, G, and R color light emitting layers, respectively.

The electron transport layer 60 and the electron injection layer 61 are sequentially formed on the hole transport layer 58 including the first, second, and third light emitting layers 59a, 59b, and 59c.

Next, a semi-transparent conductive film is deposited on the electron injection layer 61 to form the cathode electrode 62.

Then, the encap substrate 65 is bonded to the upper portion facing the TFT array substrate 51. Although not shown in the drawing, the TFT array substrate 51 and the encap substrate 65 are bonded by sealing the sealant at the edge and heat or ultraviolet curing.

As described above, the organic insulating layer 53 under the first, second, and third light emitting layers 59a, 59b, and 59c, which are B, G, and R color light emitting layers, have different thicknesses. The thickness of the organic insulating film 53 under the second light emitting layer 59b is thick, and the thickness of the organic insulating film 53 under the third light emitting layer 59c is thicker than the second light emitting layer 59b. In fact, although the organic insulating film 53 is not formed below the first light emitting layer 59a, the organic insulating film may be configured to have a thin thickness even in this region by using a diffraction exposure mask.

As described above, the wavelength of the organic insulating film 53 in the lower region is changed to match the wavelength of the first, second, and third light emitting layers 59a, 59b, and 59c, which are B, G, and R color light emitting layers, and emit light. The optical length of was adjusted to increase the color purity and light efficiency of the emitted light.

That is, in the case of the top emitting organic light emitting device, the thickness of the organic insulating layer 53 under the B, G, and R color light emitting layers is changed, so that the optical path length reflected and emitted for each color region is different. Differently, the microcavity effect was realized.

Second embodiment

First, the configuration of the organic light emitting device according to the second embodiment of the present invention will be described.

6 is a structural cross-sectional view of an organic light emitting diode according to a second exemplary embodiment of the present invention.

In the organic light emitting diode according to the second exemplary embodiment of the present invention, as illustrated in FIG. 6, a pixel region for driving the first, second, and third subpixel regions, which are three subpixel regions, as a unit is defined. A TFT array substrate 71 including TFTs for each pixel region, and first, second and third anode electrodes 72a respectively configured in the first, second and third subpixel regions on the TFT array substrate 71. , 72b, 72c, and the first, second, and third anode electrodes 72a, 72b, 72c, and the first, second, and third anode electrodes 72a, 72b, 72c, respectively. Organic insulating films 73 configured to have different thicknesses on top of each other, and first, second, and third transparent electrodes 75a configured to contact the first, second, and third anode electrodes 72a, 72b, and 72c, respectively. , 75b, 75c, a bank film 76 formed on the front surface of the first, second, and third transparent electrodes 75a, 75b, and 75c so as to expose the region flatly, and the first and second exposed films. 2, second A white organic material layer 77 formed on the entire bank film 76 including the three transparent electrodes 75a, 75b, and 75c, a cathode electrode 78 formed on the organic material layer 77, the TFT array substrate 71, Opposing substrates 90 are constructed.

At this time, the organic layer 77 is composed of a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer and an electron injection layer.

In addition, a black matrix is formed in an area of the encap substrate 90 except for the first, second, and third sub-pixel areas, and the first, second, and third sub-pixel areas are respectively formed in the encap substrate 90. And second and third color filter layers 92a, 92b and 92c.

The organic light emitting diode is a top emitting active matrix organic light emitting diode, and the first, second and third anode electrodes 72a, 72b, and 72c are formed of a reflective metal, and the cathode electrode 78 is translucent. It is made of metal.

In the above, the organic insulating film 73 configured to have a different thickness on the first, second, and third anode electrodes 72a, 72b, 72c is not formed on the first anode electrode 72a. The organic insulating film 73 on the third anode electrode 72c is thicker than the two anode electrodes 72b.

In this case, the first anode electrode 72a is in direct contact with the first transparent electrode 75a, and the first and second contact holes are formed in the organic insulating layer 73 on the second and third anode electrodes 72b and 72c. 74a and 74b are formed so that the second and third anode electrodes 72b and 72c may be connected to the second and third transparent electrodes 75b and 75c through the first and second contact holes 74a and 74b. It is in contact.

In addition, the first, second, and third transparent electrodes 75a, 75b, and 75c may be formed of indium tin oxide (ITO), tin oxide (TO), and indium zinc oxide (IZO). ) Or a transparent conductive film such as indium tin zinc oxide (ITZO).

The first, second, third color filter layers 92a, 92b, 92c are B, G, and R color filter layers, respectively.

That is, the organic insulating films 73 corresponding to the first, second, and third color filter layers 92a, 92b, and 92c which are B, G, and R color filter layers have different thicknesses, but the first color filter light layer 92a is different. Rather, the thickness of the organic insulating film 73 corresponding to the second color filter layer 92b is thicker, and the thickness of the organic insulating film 73 corresponding to the third color filter layer 92c is thicker than the second color filter layer 92b.

As described above, the organic insulating film 53 formed on the TFT array substrate 71 corresponding to the wavelengths of the first, second, and third color filter layers 92a, 92b, and 92c, which are the B, G, and R color filter layers. By varying the thickness, the optical length of the light emitting wavelength was adjusted to increase the color purity and light efficiency of the light emitting wavelength.

The light emitting path of the top emitting device is directly emitted from the organic material layer 77 through the cathode electrode 62 and the first, second, and third anode electrodes 72a, 72b, and 72c when viewed in a large view. There is a reflection through the cathode electrode 78 which is translucent electrode again.

As described above, in the case of the top emitting organic light emitting device, the organic insulating layer on the first, second and third anode electrodes 72a, 72b, 72c corresponding to the B, G, and R color filter layers By varying the thickness of 73), the microcavity effect was realized by varying the optical path length reflected and emitted for each B, G, and R color region.

Next, a method of manufacturing the organic light emitting device according to the second embodiment of the present invention having the above configuration will be described.

7A to 7E are cross-sectional views illustrating a method of manufacturing an organic light emitting diode according to a second exemplary embodiment of the present invention.

In the method of manufacturing the organic light emitting diode according to the second embodiment of the present invention, first, although not shown in the drawings, a pixel region for driving the first, second, and third subpixel regions, which are three subpixel regions, as a unit Is defined and there is a TFT array substrate 51 in which TFTs are formed for each pixel region. In this case, the TFT of each pixel region includes a gate electrode, a source electrode, and a drain electrode, and a planarization film having via holes formed thereon so as to expose the source electrode and the drain electrode of the TFT.

When formed as described above, as shown in FIG. 7A, a reflective metal is deposited on the entire TFT array substrate 71 so as to contact the drain electrode of the TFT exposed by the via hole, and the reflective metal is deposited by a photolithography process. Alternatively, the first, second, and third anode electrodes 72a, 72b, and 72c are formed in the first, second, and third subpixel regions, respectively.

Next, an organic insulating film 73 is coated on the TFT array substrate 71 including the first, second and third anode electrodes 72a, 72b, 72c.

As shown in FIG. 7B, the organic insulating film 73 is selectively exposed and developed by using the diffraction exposure mask 80 to form first and second electrodes in the first, second and third sub-pixel regions. In addition, the organic insulating layer 73 may have different thicknesses on the third anode electrodes 72a, 72b, and 72c.

In this case, the diffraction exposure mask 80 includes a transmissive region T in a region corresponding to the upper portion of the first anode electrode 72a and a semi-transmissive region composed of slits in the region corresponding to the upper portion of the second anode electrode 72b. A light transmitting region T is formed in the region HT and one region, and a light blocking region C is formed in the region corresponding to the upper portion of the third anode electrode 72c.

Accordingly, all of the organic insulating film 73 on the first anode electrode 72a is removed to completely expose the first anode electrode 72a, and the organic insulating film 73 on the second anode electrode 72b has only a predetermined thickness. It is etched so as to remain, and the organic insulating film 73 on the third anode electrode 72c remains coated. First and second contact holes 74a and 74b are formed in the second and third anode electrodes 72b and 72c, respectively. As described above, the organic insulating film 73 on the third anode electrode 72c is formed thicker than the second anode electrode 72b.

Next, as shown in FIG. 7C, a transparent conductive film is deposited on the TFT array substrate 71 including the first, second, and third anode electrodes 72a, 72b, 72c, and then transparent by a photolithography process. The conductive film is selectively etched to form first, second, and third transparent electrodes 75a, 75b, 75c so as to contact the first, second, and third anode electrodes 72a, 72b, 72c.

In this case, the first anode electrode 72a is in direct contact with the first transparent electrode 75a, and the second and third anode electrodes 72b and 72c are formed through the first and second contact holes 74a and 74b. And second and third transparent electrodes 75b and 75c.

The transparent conductive film may be formed of a material such as indium tin oxide (ITO), tin oxide (TO), indium zinc oxide (IZO), or indium tin zinc oxide (ITZO). It can be configured as.

Subsequently, as shown in FIG. 7D, an insulating film is coated on the TFT array substrate 71 including the first, second, and third transparent electrodes 75a, 75b, and 75c, and then a photolithograph process By selectively patterning the insulating film, the bank film 76 is formed so that the first, second, and third transparent electrodes 75a, 75b, 75c are flat.

At this time, the insulating film is formed of an organic insulating film.

Next, as shown in FIG. 7E, an organic material layer 77 is formed over an entire bank film 76 including the exposed first, second, and third transparent electrodes 75a, 75b, and 755c, and the organic material layer ( 77) A semi-transparent conductive film is deposited on the upper portion to form the cathode electrode 62.

The organic layer 77 is formed by sequentially depositing a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, and an electron injection layer.

Then, the encap substrate 90 is bonded to the upper portion facing the TFT array substrate 71. Although not shown in the drawing, the TFT array substrate 71 and the encap substrate 90 are bonded by heat or ultraviolet curing after sealing the sealant at the edge.

In this case, the encap substrate 90 has a black matrix formed in an area except for the first, second, and third sub-pixel areas, and the first, second, and third sub-pixel areas have a black matrix. The second and third color filter layers 92a, 92b and 92c are configured.

In this case, the first, second and third color filter layers 92a, 92b and 92c are B, G and R color filter layers, respectively.

As described above, the organic insulating film 53 of the TFT array substrate 71 corresponding to the first, second, and third color filter layers 92a, 92b, 92c, which are B, G, and R color filter layers, has a thickness. Are different from each other, the thickness of the organic insulating film 73 formed in the portion corresponding to the second color filter layer 92b is thicker than the first color filter layer 92a, and the third color filter layer 92c is larger than the second color filter layer 92b. The thickness of the organic insulating film 73 formed on the TFT array substrate 71 corresponding to the thickness is large. In fact, although the organic insulating film 73 is not formed in the portion corresponding to the first color filter layer 92a, the organic insulating film may be configured to have a thin thickness even in this region using a diffraction exposure mask.

As described above, the thickness of the organic insulating film 73 on the TFT array substrate 71 corresponding to the wavelengths of the first, second, and third color filter layers 92a, 92b, and 92c, which are B, G, and R color filter layers. The optical length of the light emitting wavelength was adjusted to increase the color purity and light efficiency of the light emitting wavelength.

That is, in the case of the top emitting organic light emitting device, the thickness of the organic insulating layer 73 on the first, second, and third anode electrodes 72a, 72b, and 72c corresponding to the B, G, and R color filter layers is increased. By differently, the microcavity effect was realized by varying the optical path length reflected and emitted for each B, G, and R color region.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the spirit of the present invention.

Therefore, the technical scope of the present invention should not be limited to the contents described in the above embodiments, but should be defined by the claims.

The organic light emitting device and the method of manufacturing the same according to the present invention as described above have the following effects.

First, by forming different thicknesses of the organic insulating film of each sub pixel region corresponding to the R, G, B light emitting layer or the R, G, B color filter layer, the optical path length is determined for each R, G, B region. Alternatively, the microcavity effect can be realized. That is, by obtaining an optical path length suitable for the light emitted by the R, G, and B light emitting layers, it is possible to increase the emission color purity and luminance of each of the R, G and B light emitting layers.

Second, since the thickness of the organic insulating film of each sub pixel region corresponding to the R, G, B light emitting layer or the R, G, B color filter layer can be formed differently using one diffraction exposure mask, the productivity can be simplified by simplifying the process. Can be improved.

Claims (33)

A TFT array substrate having a TFT array and first, second, and third sub pixel regions defined therein; First, second and third anode electrodes respectively formed in the first to third sub pixel regions of the TFT array substrate; First, second and third transparent electrodes configured to contact the first, second and third anode electrodes, respectively; An organic material layer including first, second, and third light emitting layers each having first, second, and third colors corresponding to the first to third sub-pixel areas; An organic insulating layer having different thicknesses under the first, second, and third light emitting layers; A cathode electrode formed on the organic material layer; And an encap substrate bonded to the TFT array substrate. The method of claim 1, And the first, second, and third light emitting layers are B, G, and R color light emitting layers, respectively. The method of claim 1, In the organic layer, a hole injection layer and a hole transport layer are stacked, and first, second, and third light emitting layers are formed in each of the sub-pixel regions, and electrons are formed on the upper portion including the first, second, and third light emitting layers. An organic light emitting device, characterized in that the transport layer and the electron injection layer is laminated. The method of claim 1, And the organic insulating layer is formed on a layer between the first, second and third anode electrodes and the first, second and third transparent electrodes. The method of claim 1, The organic insulating film is not formed in a lower region corresponding to the first light emitting layer, and the organic insulating film under the third light emitting layer is thicker than the lower portion corresponding to the second light emitting layer. device. The method of claim 1, First and second contact holes are formed in the organic insulating layer under the second and third light emitting layers to expose the first and second anode electrodes. The first anode electrode is in direct contact with the first transparent electrode, And the second and third anode electrodes are in contact with the second and third transparent electrodes through the first and second contact holes. The method of claim 1, The bank of the organic light emitting device, characterized in that the bank layer is further formed under the organic material layer so that one region of the first, second, third transparent electrode is evenly exposed. The method of claim 1, And the first, second and third anode electrodes are formed of a reflective metal. The method of claim 1, The cathode electrode is an organic light emitting device, characterized in that composed of a translucent metal. The method of claim 1, The first, second and third transparent electrodes may be formed of indium tin oxide (ITO), tin oxide (TO), indium zinc oxide (IZO), or indium tin oxide (Indium Tin). An organic light emitting device comprising a transparent conductive film such as Zinc Oxide (ITZO). A TFT array substrate having a TFT array and first, second, and third sub pixel regions defined therein; First, second and third anode electrodes respectively formed in the first to third sub pixel regions of the TFT array substrate; First, second and third transparent electrodes configured to contact the first, second and third anode electrodes, respectively; A bank film formed such that one region of the first, second, and third transparent electrodes is flatly exposed; An organic material layer formed on the bank layer including the first, second and third transparent electrodes; A cathode electrode formed on the organic material layer; An encap substrate opposed to and bonded to the TFT array substrate, the encap substrate comprising a first, second and third color filter layers on top of the first, second and third sub-pixel regions; And an organic insulating layer having different thicknesses on the TFT array substrate including the first, second and third anode electrodes corresponding to the first, second and third color filter layers of the encap substrate. An organic light emitting device characterized in that. The method of claim 11, And the first, second, and third color filter layers are B, G, and R color filter layers, respectively. The method of claim 11, The organic insulating layer corresponding to the first, second, and third color filter layers may have a thicker thickness of the organic insulating layer corresponding to the second color filter layer than the first color filter light layer, and may be thicker than the second color filter layer. An organic light-emitting device, characterized in that the thickness of the organic insulating film corresponding to the three color filter layer. The method of claim 11, The organic material layer is an organic light emitting device, characterized in that the hole injection layer, the hole transport layer, the light emitting layer, the electron transport layer and the electron injection layer. The method of claim 11, And the black matrix is further formed in an area of the encap substrate except for the first, second and third sub-pixel areas.  The method of claim 11, The organic insulating film is not formed in a region corresponding to the first color filter layer, and is formed such that a portion corresponding to the third color filter layer is thicker than a region corresponding to the second color filter layer. Light emitting element. The method of claim 11, First and second contact holes are formed in the organic insulating layer to expose the first and second anode electrodes. The first anode electrode is in direct contact with the first transparent electrode, And the second and third anode electrodes are in contact with the second and third transparent electrodes through the first and second contact holes. The method of claim 11, And the first, second and third anode electrodes are formed of a reflective metal. The method of claim 11, The cathode electrode is an organic light emitting device, characterized in that composed of a translucent metal. The method of claim 11, The first, second and third transparent electrodes may be formed of indium tin oxide (ITO), tin oxide (TO), indium zinc oxide (IZO), or indium tin oxide (Indium Tin). An organic light-emitting device comprising a transparent conductive film such as Zinc Oxide (ITZO). A first step of forming first, second and third anode electrodes in the first, second and third sub pixel regions defined in the TFT array substrate, respectively; Forming an organic insulating layer on the first, second and third anode electrodes to have different thicknesses using a diffraction exposure mask; A third step of forming first, second, and third transparent electrodes to be in contact with the first, second, and third anode electrodes, respectively; Forming a bank film such that one region of the first, second, and third transparent electrodes is evenly exposed; A fifth step of forming an organic material layer on the bank layer to include first, second and third light emitting layers having first, second and third colors on the first to third sub pixel areas; A sixth step of forming a cathode on the organic material layer; And a seventh step of attaching an encap substrate to face the TFT array substrate. The method of claim 21, Forming the hole injection layer and the hole transport layer on the entire surface of the bank layer including the first, second, and third transparent electrodes in order; Forming first, second, and third light emitting layers having first, second, and third colors, respectively, on the hole transport layer corresponding to the first, second, and third transparent electrodes by using a shadow mask. step; And sequentially forming an electron transporting layer and an electron injection layer on the hole transporting layer including the first, second, and third light emitting layers. The method of claim 21, The first, second and third light emitting layer is a manufacturing method of an organic light emitting device, characterized in that each of the B, G, R color light emitting layer. A first step of forming first, second and third anode electrodes in the first, second and third sub pixel regions defined in the TFT array substrate, respectively; Forming an organic insulating layer on the first, second and third anode electrodes to have different thicknesses using a diffraction exposure mask; Forming a first, second, and third transparent electrode to be in contact with the first, second, and third anode electrodes, respectively; A third step of forming a bank layer such that one region of the first, second, and third transparent electrodes is evenly exposed; A fourth step of forming an organic material layer on the bank layer including the first, second and third transparent electrodes; A fifth step of forming a cathode on the organic material layer; And attaching an encap substrate having first, second and third color filter layers on top of the first, second and third sub-pixel regions so as to face the TFT array substrate. The manufacturing method of the organic light emitting element characterized by the above-mentioned. The method of claim 21 or 24, And the first, second and third anode electrodes are formed on the first, second and third sub-pixel regions by selectively etching and then etching the reflective metal. The method of claim 21 or 24, The diffraction exposure mask, which has etched the organic insulating layer, may include a transmissive region T in a region corresponding to an upper portion of the first anode electrode, and a translucent region composed of slits in an region corresponding to the upper portion of the second anode electrode. A light emitting area is formed in an area, and a light blocking area (C) and a light transmitting area (T) are formed in an area corresponding to an upper portion of the third anode electrode. The method of claim 21 or 24, And the organic insulating layer is thicker on the second anode electrode than on the first anode electrode, and thicker on the third anode electrode than on the second anode electrode. The method of claim 26, All of the organic insulating layer on the first anode electrode is removed to completely expose the first anode electrode, and the organic insulating layer on the second anode electrode is removed so that only a predetermined thickness remains, and the upper portion of the third anode electrode is removed. The organic insulating film remains coated and the first and second contact holes are formed in the second and third anode electrodes, respectively. The method of claim 21 or 24, The first, second and third transparent electrodes may be formed of indium tin oxide (ITO), tin oxide (TO), indium zinc oxide (IZO), or indium tin oxide (Indium Tin). A method of manufacturing an organic light emitting device, characterized in that it is formed of a transparent conductive film such as Zinc Oxide (ITZO). The method of claim 21 or 24, And the bank film is formed of an organic insulating film. The method of claim 21 or 24, The cathode electrode is a method of manufacturing an organic light emitting device, characterized in that formed by depositing a translucent conductive film. The method of claim 24, The organic material layer is a method of manufacturing an organic light emitting device, characterized in that formed by depositing a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, and an electron injection layer. The method of claim 24, The first, second, and third color filter layers are B, G, R color filter layers, respectively.

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