KR101827399B1

KR101827399B1 - Organic light emitting display device with light-scattering layer

Info

Publication number: KR101827399B1
Application number: KR1020150094322A
Authority: KR
Inventors: 장지향; 김수강; 조소영; 구원회; 임현수
Original assignee: 엘지디스플레이 주식회사
Priority date: 2015-07-01
Filing date: 2015-07-01
Publication date: 2018-02-09
Also published as: KR20170005248A

Abstract

According to one aspect of the present invention, there is provided an organic light emitting display including a scattering layer, wherein the overcoat layer includes microlenses arranged in the entire light emitting region and a part of the non-light emitting region, In another aspect of the present invention, there is provided an organic light emitting diode display comprising: an overcoat layer in which a microlens disposed in a center portion of a light emitting region and a microlens disposed in an outer periphery of a center portion are arranged in different patterns; And an organic light emitting display device including the banks.

Description

TECHNICAL FIELD [0001] The present invention relates to an organic light emitting diode (OLED) display device,

The present invention relates to an organic light emitting display device including a scattering layer.

2. Description of the Related Art [0002] As an information-oriented society develops, there have been various demands for a display device for displaying images. Recently, a liquid crystal display (LCD), a plasma display panel (PDP) Various display devices such as an organic light emitting display (OLED) and the like are being utilized. Such various display apparatuses include display panels corresponding thereto.

Thin film transistors are formed in each pixel region of the display panel, and a specific pixel region in the display panel is controlled through the current flow of the thin film transistor. The thin film transistor is composed of a gate and a source / drain electrode.

In the organic light emitting diode display, an organic light emitting layer is formed between two different electrodes. When electrons generated in one electrode and holes generated in another electrode are injected into the organic light emitting layer, the injected electrons and holes are combined, and an exciton is generated, and the generated exciton emits light while falling from an excited state to a ground state, thereby displaying an image.

On the other hand, a scattering layer, for example, a microlens may be disposed in the pixel region (or the sub-pixel region) in order to increase the light efficiency, so that the scattering effect of the organic light emitting layer can be obtained. However, when the microlenses are disposed at the boundary of the pixel region, the stability of the device in the deposition of the organic light-emitting layer may be impaired due to the step difference of the pixel region defined by the bank. However, when the microlens is not disposed in the boundary region of the pixel region, the light efficiency can not be increased.

In view of the foregoing, it is an object of the present invention to increase the light efficiency by disposing a scattering layer on an organic light emitting display or a display panel.

An object of the present invention is to provide a scattering layer in an overcoat so that the entire organic emission layer in a pixel region can emit light, thereby increasing light efficiency.

It is another object of the present invention to improve the device stability of the organic light emitting layer by reducing the steps of the scattering layer and the bank which are overlapped with the scattering layer.

In order to achieve the above object, in one aspect, the present invention provides an organic light emitting diode display including an overcoat layer in which microlenses are arranged in a whole of a light emitting region and a part of a non-light emitting region, and a bank defining the light emitting region .

According to another aspect of the present invention, there is provided an organic light emitting diode display comprising an overcoat layer in which a microlens disposed in a center portion of a light emitting region and a micro lens disposed in an outermost portion of a center portion are arranged in different patterns, Lt; / RTI >

According to still another aspect of the present invention, there is provided an organic light emitting display in which an anode electrode, an organic light emitting layer, and a cathode electrode are disposed on the above-described overcoat layer, and an anode electrode and an organic light emitting layer are deposited according to the bending of the above- do.

As described above, according to the present invention, a scattering layer is disposed on a display panel to eliminate the phenomenon that the light emitted from the organic light emitting layer is trapped while being totally reflected within the ITO and the organic light emitting layer.

In addition, according to the present invention, the banks are arranged on the microlens array, and the organic light emitting layer is stably deposited to increase stability and lifetime of the device.

In addition, according to the present invention, when the banks are arranged in contact with the microlenses in the pixel or sub-pixel region, the pattern of the microlens array is different, and the organic light emitting layer is stably deposited to increase the stability and lifetime of the device. have.

Further, according to the present invention, the organic light emitting layer in the pixel or sub-pixel region in which the banks are arranged can be stably deposited to increase the lifetime of the device and the lifetime of the display panel.

1 is a view schematically showing a display device according to embodiments.
2 is a cross-sectional view of the microlens of the present invention.
FIG. 3 is a view illustrating a structure in which bank positions of edges of a sub-pixel region are adjusted according to an exemplary embodiment of the present invention.
FIG. 4 is a view showing a configuration of a mask for disposing the microlens array as shown in FIG. 2. FIG.
5 is a view showing a configuration of a mask for disposing the microlens array as shown in FIG.
FIG. 6 is a view illustrating a structure in which heights of microlens arrays formed in a sub-pixel region according to another embodiment of the present invention are different in height in a boundary region.
7 is a view illustrating a structure in which a bank covers a part of a microlens array formed in a sub-pixel region according to another embodiment of the present invention.
8 is a view showing a configuration in which a microlens according to an embodiment of the present invention is disposed in an outer portion of a light emitting region.
9 is a view showing a configuration in which a microlens according to another embodiment of the present invention is disposed in an outer portion of a light emitting region.
10 is a view illustrating a configuration in which a microlens according to another embodiment of the present invention is disposed at an outer portion of a light emitting region and a boundary line of the bank is disposed to overlap a specific portion of the microlens.
11 is a view showing a configuration in which the shape of a microlens according to an embodiment of the present invention is different in a center part and an outer part of a light emitting area.
FIG. 12 is a view showing a configuration in which a microlens according to another embodiment of the present invention is disposed at an outer portion of a light emitting region, and a boundary line of the bank is disposed to overlap a specific portion of the microlens.
FIG. 13 is a view showing a mask for controlling the microlens array according to an embodiment of the present invention such that the microlens arrays are arranged at different positions in the central part and the outer part.

Hereinafter, some embodiments of the present invention will be described in detail with reference to exemplary drawings. In the drawings, like reference numerals are used to denote like elements throughout the drawings, even if they are shown on different drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

In describing the components of the present invention, terms such as first, second, A, B, (a), and (b) may be used. These terms are intended to distinguish the components from other components, and the terms do not limit the nature, order, order, or number of the components. When a component is described as being "connected", "coupled", or "connected" to another component, the component may be directly connected or connected to the other component, Quot; intervening "or that each component may be" connected, "" coupled, "or " connected" through other components.

1 is a view schematically showing a display device according to embodiments.

Referring to FIG. 1, a display device 100 according to an embodiment includes a plurality of first lines VL1 to VLm formed in a first direction (e.g., a vertical direction) A display panel 110 on which a plurality of second lines HL1 to HLn are formed, a first driver 120 for supplying a first signal to a plurality of first lines VL1 to VLm, A second driver 130 for supplying a second signal to the first and second lines HL1 to HLn and a timing controller 140 for controlling the first and second drivers 120 and 130.

The display panel 110 is provided with a plurality of first lines VL1 to VLm formed in a first direction (e.g., a vertical direction) and a plurality of second lines HL1 to HLn formed in a second direction (e.g., A plurality of pixels (P) are defined according to the intersection of the pixels.

Each of the first driving unit 120 and the second driving unit 130 may include at least one driver IC for outputting a signal for displaying an image.

A plurality of first lines VL1 to VLm formed in the first direction on the display panel 110 are formed in a vertical direction (first direction) to transmit a data voltage (first signal) And the first driver 120 may be a data driver for supplying the data voltage to the data line.

A plurality of second lines HL1 to HLn formed in the second direction on the display panel 110 are formed in a horizontal direction (second direction) to form a gate signal (first signal) And the second driver 130 may be a gate driver for supplying a scan signal to the gate line.

In addition, a pad portion is formed on the display panel 110 to connect the first driver 120 and the second driver 130. When the first driver 120 supplies a first signal to the plurality of first lines VL1 through VLm, the pad unit transmits the first signal to the display panel 110 and the second driver 130 similarly applies a plurality of second lines HL1 to HLn), and transmits the second signal to the display panel (110).

Each pixel includes one or more subpixels. The sub-pixel means a unit in which a specific kind of color filter is formed, or a color filter is not formed and the organic light emitting element can emit a specific color. (R), green (G), blue (B), and optionally white (W) as the color defined by the sub-pixel, but the present invention is not limited thereto.

Since each sub-pixel includes a separate thin-film transistor and an electrode connected thereto, the sub-pixels constituting the pixel are also referred to as one pixel region. A first line may be arranged for each sub-pixel, and a plurality of sub-pixels constituting the pixel may share a specific first line. The configuration of the pixel / sub-pixel and the first line / second line may be variously modified and the present invention is not limited thereto. Hereinafter, the pixel region or the sub-pixel region may be used without any distinction, and all independent regions where light emission is controlled by one thin film transistor are indicated.

An electrode connected to a thin film transistor for controlling light emission of each pixel / sub pixel region of a display panel is referred to as a first electrode and an electrode disposed on the entire surface of the display panel or arranged to include two or more pixel regions is referred to as a second electrode .

When the first electrode is an anode electrode, the second electrode is a cathode electrode, and vice versa. Hereinafter, the anode electrode will be described as an embodiment of the first electrode, and the cathode electrode will be described as an example of the second electrode, but the present invention is not limited thereto.

In the above-described sub-pixel region, a color filter of a single color is disposed or not disposed. The color filter converts the color of a single organic light emitting layer into a color of a specific wavelength. In addition, a light-scattering layer may be disposed in each sub-pixel region to enhance light extraction efficiency of the organic light emitting layer. The above-described scattering layer can be indicated by a microlens array, a nano pattern, a diffuse pattern, or a silica bead.

2 is a cross-sectional view of the microlens of the present invention. And a portion of the sub-pixel region is enlarged. A buffer layer, a thin film transistor, or the like may be disposed on the substrate 201, but this is not shown for the sake of convenience. A part of the overcoat layer 235 is etched to arrange the microlenses and a first electrode or an anode 240 is disposed on the first electrode 250. A bank 250 is disposed at a boundary portion of the sub- . The color filter 290 may be selectively disposed. An organic light emitting layer (not shown) and a second electrode or cathode (not shown) are disposed on a first electrode or an anode 240 as an example. On the other hand, the microlens 295 diffuses light to increase light extraction efficiency. Reference numeral 287 denotes a region in which banks are arranged, and 285 denotes a boundary region in which microlenses are not arranged.

On the other hand, the steps of the microlenses in the boundary region 285 of the sub-pixel region can be as large as 299 because of the formation of the banks and the boundary between the sub-pixel regions. However, when the step of the microlens 295 is large like 299, the anode 240, the organic light emitting layer, and the cathode that are deposited thereon can be thinly deposited. Particularly, when the thickness of the organic light emitting layer is reduced, a short circuit occurs between the anode 240 and the cathode or shrinkage occurs.

Herein, in order to solve the step difference of the microlens in the boundary region of the sub-pixel region, the position of the bank is adjusted or the height or the interval of the microlens array is adjusted.

FIG. 3 is a view illustrating a structure in which bank positions of edges of a sub-pixel region are adjusted according to an exemplary embodiment of the present invention. Reference numeral 387 denotes an area in which banks are arranged, and reference numeral 385 denotes a boundary area in which microlenses are not arranged. Some of the portions excluding 387 to 385 are arranged in a microlens even though they are non-emission regions.

Unlike FIG. 2, the microlenses 395 are disposed up to the boundary region 385 of the sub-pixel region. Further, the bank 350 is disposed on the microlens. In FIG. 2, the microlens array is not disposed at the outer portion of the sub-pixel region, and a sharp step is generated at the end portion 299 of the overcoat layer. However, in the embodiment of FIG. 3, the microlens array is arranged up to the boundary region 385 The step generated at the height of the bank can be reduced. 3, the microlens array is arranged in a wider area than the light emitting area to prevent the increase of the step and maintain the thickness of the organic light emitting layer. Further, since the organic light emitting layer maintains the thickness, a short circuit is prevented between the anode electrode and the cathode electrode. On the other hand, it is possible to arrange the microlens array only in a part of the non-emission area and prevent the microlens array from being arranged between the sub-pixel areas like 385, thereby increasing the adhesion between the bank and the anode electrode.

FIG. 4 is a view showing a configuration of a mask for disposing the microlens array as shown in FIG. 2. FIG. In the region 287 and the boundary region 285 in which the banks of FIG. 2 are arranged, no pattern is arranged in the mask so as not to form microlenses.

5 is a view showing a configuration of a mask for disposing the microlens array as shown in FIG. A mask pattern for forming a microlens array is disposed in a region 387 where the banks of Fig. 3 are arranged. That is, the bank region is wider than the region 385 in which the microlens array is not disposed, so that the step of the microlens array in the boundary region can be lowered, thereby preventing the anode-cathode short-circuit due to the thickness reduction of the organic light- It is possible to reduce the level difference between the bank and the microlens disposed at the boundary of the sub-pixel region by arranging the microlenses in the region 387 in which the banks are arranged and the non-emission region, and the thickness of the organic light- Thereby preventing a short circuit between the electrode and the cathode electrode. When the mask is designed as shown in FIG. 5 and the microlenses are arranged on the overcoat layer using the mask, the banks cover the microlens array, so that the steps of the microlenses disposed in the overcoat layer are relaxed to improve the stability .

FIG. 6 is a view illustrating a structure in which heights of microlens arrays formed in a sub-pixel region according to another embodiment of the present invention are different in height in a boundary region.

The depth d1 of the microlens disposed in the boundary region 610 and the depth d2 of the microlens disposed in the portion 620 corresponding to the center portion are different from each other. The microlenses disposed in the boundary region 610 lower the level difference to prevent the anode-cathode short-circuit and solve the shrinkage problem in the process of disposing the organic light-emitting layer in the region 690.

The bank 650 of FIG. 6 may be disposed in contact with the border region 610. In another embodiment, the bank 650 may be disposed to cover the border region 610. [

In order to arrange the sizes of the microlenses of the central portion and the outer portion differently in one sub-pixel region as shown in FIG. 6, the microlens array can change the shape according to the diameter and the gap. It is possible to change the diameter and the condition of the gap of the microlens array mask arranged in the outer frame portion of the light emitting portion of the sub pixel region to reduce the step with the bank.

That is, the diameter and the gap of the mask can be adjusted so that the microlens array in the sub-pixel region of the present invention can have a different shape for each region. When this is controlled, the mask corresponding to the outer portion of the sub-pixel region may be configured to have a small diameter, which is planarized at the upper portion to receive small light at the same exposure dose. In this manner, in order to alleviate the stepped portion of the outer edge of the microlens array, a mask is formed in the outer portion of the microlens array mask of the overcoat layer to be distinguished from the central portion.

7 is a view illustrating a structure in which a bank covers a part of a microlens array formed in a sub-pixel region according to another embodiment of the present invention. In FIG. 6, a structure in which the banks 650 are arranged to be engaged with the boundary line in which the microlens array is formed has been described. In FIG. 7, the banks 750 are arranged so as to partially cover the boundary line where the microlens array is formed.

A part of the boundary region 610 having the shallow depth of the microlens array is arranged so that the banks 750 are arranged to increase the safety of the devices in the boundary region. The microlenses disposed in the boundary region 610 lower the level difference to prevent the anode-cathode short-circuit and solve the shrinkage problem in the process of disposing the organic light-emitting layer in the region 790.

6 and 7, it is possible to planarize the overcoat layer in the outer portion of the sub-pixel region to alleviate the step of the region where the organic light-emitting layer is deposited. It is possible to prevent the organic light emitting layer from being thinly deposited by a sharp step, thereby contributing to improvement of reliability in manufacturing the device. Further, the organic light emitting layer is disposed on the microlens array to maximize the light extracting effect. Such light extracting effect can be arranged at the center of the sub-pixel region to increase the efficiency of the device.

8 is a view showing a configuration in which a microlens according to an embodiment of the present invention is disposed in an outer portion of a light emitting region.

A plurality of thin film transistors arranged on the substrate of the organic light emitting display device, a light emitting region 810 whose light emission is controlled by the thin film transistor, and a sub pixel region 820 composed of a non-light emitting region. The non-emission region is a portion of the sub-pixel region 820 excluding the emission region 810.

The area where the microlenses are arranged in the overcoat layer is denoted by 830. [ An overcoat layer is formed so that a plurality of microlenses are arranged in the entire area of the light emitting area 810 and the area indicated by 830 which is a part of the non-light emitting area. And the anode electrode is arranged in the sub-pixel region on the overcoat layer. In addition, the bank is disposed in the outer portion of the light emitting region, and the bank is disposed on the microlens arranged in the non-light emitting region.

8 is a sectional view in which the microlenses are arranged. The area where the banks are arranged is the same as 850, and it can be confirmed that some of them overlap with 830a.

After the banks are disposed, the organic light emitting layer and the cathode electrode are disposed. The stepped portion at the boundary of the light emitting portion becomes shallow due to the overlapping of the region 850 where the banks are arranged and the region 830a where the micro lenses are arranged, As a result, the deposition of the organic light emitting layer is stably performed, thereby increasing the lifetime of the device and improving the reliability of the display panel.

On the other hand, the microlens array arranged in the non-emission area can be arranged in a different shape from the microlens array arranged in the emission area. For example, the microlenses may have different depths or heights, as in the embodiments illustrated in FIGS. 6 and 7 above. This will be described in more detail in Fig.

9 is a view showing a configuration in which a microlens according to another embodiment of the present invention is disposed in an outer portion of a light emitting region. The height of the microlenses of the center portion 830b is higher than the height of the microlenses of the outer frame 830c. This is to alleviate the difference in the step height when the bank 850 is disposed. The difference between the height of the microlenses of the outer frame portion 830c and the height of the microlenses of the center portion 830b can be made smaller or equal to the height of the banks.

10 is a view illustrating a configuration in which a microlens according to another embodiment of the present invention is disposed at an outer portion of a light emitting region and a boundary line of the bank is disposed to overlap a specific portion of the microlens. In FIG. 8, the portion 830a is enlarged. It can be confirmed at 830a that a microlens is arranged to the outer frame of the light emitting region 810. In addition, the bank is disposed at a specific point 831 of the microlens of the outer frame so as to alleviate a step between the bank and the microlens, thereby stably depositing the organic light emitting layer. For example, the bank boundary may be located between the highest position 1001 and the lowest position 1002, thereby alleviating the step difference so that the organic light emitting layer is deposited stably after the banks are disposed.

11 is a view showing a configuration in which the shape of a microlens according to an embodiment of the present invention is different in a center part and an outer part of a light emitting area. The sub-pixel region 1120 includes a light emitting region 1110 and other non-light emitting regions. The light emitting region 1110 is composed of a central portion 1131 in which a microlens of a first shape is arranged and a region 1132 in which a microlens of a second shape is arranged in an outer portion 1132 of the central portion, Are different in shape. The boundary line of the region 1132 in which the microlenses of the second shape are arranged may match the boundary line of the light emitting region 1110 and 1132 may be arranged to be somewhat larger than 1110. [

The bank is disposed in the region indicated by 1150, that is, in the outer portion of the light emitting region 1110. Here, if the area 1132 in which the microlenses of the second shape are arranged is larger than the light emitting area 1110, the microlenses of the second shape may be arranged under the banks.

The first shape and the second shape vary depending on the depth or height of the microlens, and the depth or height of the microlens of the first shape is larger than the depth or height of the microlens of the second shape. The depth or height of the microlens is deeper or higher as it goes from the outer portion of the luminescent region to the center of the luminescent region to alleviate the sharp step change of the microlens array and thereby increase the stability of the organic luminescent layer disposed on the microlens array .

FIG. 12 is a view showing a configuration in which a microlens according to another embodiment of the present invention is disposed at an outer portion of a light emitting region, and a boundary line of the bank is disposed to overlap a specific portion of the microlens. 1132 and 1131 are enlarged in Fig. It can be confirmed from 1132 that the microlenses are arranged to the outer frame near the boundary of the light emitting region 1110. In addition, the banks are arranged at specific points 1231 of the microlenses of the outer frame, so that the steps of the banks and the microlenses are relieved so that the organic light emitting layer can be stably deposited. For example, even if the bank is arranged with the boundary line of the bank positioned between the highest position 1201 and the lowest position 1202, the step can be relaxed so that the organic light emitting layer is deposited stably.

FIG. 13 is a view showing a mask for controlling the microlens array according to an embodiment of the present invention such that the microlens arrays are arranged at different positions in the central part and the outer part.

In the center portion of the sub-pixel region, a mask structure is formed as shown at 1131, so that the microlenses are arranged more deeply, and the outer portion of the sub-pixel region has a mask structure like 1132 so that the microlenses are arranged somewhat shallow. Accordingly, the step difference of the microlenses between the boundary portion and the center portion of the sub pixel region is gradually generated, so that the anode electrode material, the organic light emitting layer, and the cathode electrode material disposed on the microlens can be stably deposited. Particularly, the boundary portion is an area in which the bank is arranged and the step may change abruptly. The height or the depth of the microlens in this portion may be smaller than the height or the depth of the microlens in the center portion, . In FIG. 13, the interval between the microlenses is reduced so that the height or depth of the microlenses in the 1132 region is set to be low or shallow at the same exposure dose.

In addition, the diameters of the micro lenses 1131 and 1132 can be adjusted. For example, the diameter of the microlenses in the 1131 region is made larger than the diameter of the microlenses in the 1132 region, so that the height or depth of the microlenses in the 1132 region is set to be low or shallow at the same exposure dose.

Also, the slopes of the microlenses can be adjusted by controlling the diameters of the open regions (or closed regions) of the masks 1132 and 1131.

In the method of disposing the microlens array on the overcoat layer, both a negative photoresist and a positive photoresist can be used, so that a normal mask and a reverse phase mask can be used.

In one embodiment, the pattern of the microlens array may be arranged in a region wider than the light emitting region so that the microlens array is arranged in the outer portion of the light emitting region.

In another embodiment, the mask may be arranged such that the height or depth of the microlens is large at the central portion of the light emitting region so that the pattern of the microlens array between the central portion and the outer frame portion of the light emitting region is different, And the height or depth of the microlens may be shallow.

In the case of applying the embodiment of the present invention, the steps of the microlenses are arranged to be reduced in the edge region of the microlens array in the sub-pixel region so that abrupt step is not generated, the organic light emitting layer is thinly deposited, the shrinkage is not caused, thereby increasing the lifetime of the device and increasing the stability of the device.

In one embodiment, the microlens arrays are arranged to be wider than the light emitting region, so that the bank covers the microlens array, thereby reducing the step.

In another embodiment, the microlens array may be arranged such that the central portion and the outer periphery of the microlens array are arranged in different shapes so that the steps are not large even if the banks are arranged in the outer portions of the emission regions.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the present invention as defined by the appended claims. , Separation, substitution, and alteration of the invention will be apparent to those skilled in the art. Therefore, the embodiments disclosed in the present invention are intended to illustrate rather than limit the scope of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be construed according to the following claims, and all technical ideas within the scope of equivalents should be construed as falling within the scope of the present invention.

100: display device 110: display panel
120: first driving part 130: second driving part
140: timing controller 235: overcoat layer
240: anode electrode 250, 350, 650, 750, 1050: bank
295, 395: microlenses 810, 1110: light emitting region

Claims

A substrate including a plurality of sub-pixel regions divided into a light emitting region and a non-light emitting region disposed in an outer portion of the light emitting region;
A plurality of thin film transistors arranged on the substrate;
An overcoat layer disposed on the substrate on which the thin film transistor is disposed, the overcoat layer having a plurality of microlenses formed over the entire luminescent region and a part of the non-luminescent region;
A first electrode disposed on the microlens on the sub-pixel region;
A bank covering a part of the outer frame of the microlens formed in a part of the non-emission region and the non-emission region; And
A first electrode, an organic light emitting layer disposed on the bank, and a second electrode,
The overcoat layer further includes a stepped portion disposed between the plurality of sub-pixel regions and having a flat surface on which the microlenses are not disposed, and a stepped portion between the microlenses formed on a part of the non-emitting region and the flat surface,
A boundary line of the bank is disposed between a highest position and a lowest position of the microlens formed in a part of the non-emission region,
Wherein the bank covers the planar surface of the overcoat layer and the step and the lowest position,
And a microlens formed in a portion of the non-emission region is positioned higher than a microlens formed in the emission region.

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The method according to claim 1,
The depth of the microlens formed in a part of the non-emission region is lower than the depth of the microlens formed in the emission region,
And the diameter of the microlens formed in a part of the non-emission region is smaller than the diameter of the microlens disposed in the central portion of the emission region.

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A substrate including a plurality of sub-pixel regions divided into a light emitting region and a non-light emitting region disposed in an outer portion of the light emitting region;
A plurality of thin film transistors arranged on the substrate;
An overcoat layer disposed on the substrate on which the thin film transistor is disposed, the overcoat layer having a plurality of microlenses formed in different patterns on a central portion of the light emitting region and an outer perimeter of the central portion;
A first electrode disposed on the microlens on the sub-pixel region;
A bank covering a part of an outer frame of the microlens formed outside the central part of the light emitting area and the non-emitting area; And
A first electrode, an organic light emitting layer disposed on the bank, and a second electrode,
Wherein the overcoat layer further includes a flat surface disposed between the plurality of sub-pixel regions and not disposed with the microlenses, and a stepped recess formed between the microlenses formed on the outer periphery of the central portion of the light emitting region and the flat surface,
The boundary line of the bank is disposed between the highest position and the lowest position of the microlens formed at the outer periphery of the center of the light emitting area,
Wherein the bank covers the planar surface of the overcoat layer and the step and the lowest position,
And a microlens disposed outside the central portion of the light emitting region is positioned higher than a microlens disposed at a central portion of the light emitting region.

6. The method of claim 5,
The depth of the microlens disposed outside the central portion of the light emitting region is lower than the depth of the microlens disposed at the central portion of the light emitting region,
Wherein a diameter of the microlens disposed outside the center of the light emitting region is smaller than a diameter of the microlens disposed at the center of the light emitting region.

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