KR102016070B1 - Flexible organic luminescence emitted diode device and method for fabricating the same - Google Patents

Abstract

The present invention relates to a flexible organic light emitting display device and a method of manufacturing the same. The disclosed invention includes: a display area including a plurality of pixel areas and a substrate in which a non-display area is defined outside thereof; A plurality of thin film transistors formed in the pixel area and the non-display area on the substrate; A planarization film formed on an entire surface of the substrate including the thin film transistors and having at least one concave pattern having a radius of curvature; A first electrode formed on the planarization layer and connected to the thin film transistor of the display area; A bank formed around each pixel region of the substrate including the first electrode; An organic emission layer formed on each of the pixel areas above the first electrode; A second electrode formed on an entire surface of the substrate including the organic light emitting layer; A first passivation film formed on an entire surface of the substrate including the second electrode; An organic film formed on the first passivation film; A second passivation film formed on the organic film and the first passivation film; A protective film facing the substrate; And an adhesive interposed between the substrate and the protective film to form a panel state by adhering the substrate and the protective film.

Description

FLEXIBLE ORGANIC LUMINESCENCE EMITTED DIODE DEVICE AND METHOD FOR FABRICATING THE SAME

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an organic luminescence emitting diode device (hereinafter referred to as "OLED"), and more particularly to correcting a difference in stress caused by bending to correct a defect generated during bending. The present invention relates to an improved flexible organic EL device and a method of manufacturing the same.

One of the flat panel displays (FPD), an organic light emitting display device has high luminance and low operating voltage characteristics. In addition, the self-luminous self-illuminating type provides high contrast ratio, enables ultra-thin display, easy response sphere with a response time of several microseconds (μs), no restriction on viewing angle, and low temperature. It is stable even in the case of driving at low voltage of DC 5-15V, so that the fabrication and design of the driving circuit is easy.

In addition, the manufacturing process of the organic electroluminescent device is very simple because the deposition (deposition) and encapsulation (encapsulation) equipment is all.

The organic light emitting diode having such characteristics is classified into a passive matrix type and an active matrix type. In the passive matrix method, the scan line and the signal line cross each other to form a device in a matrix form, and each pixel Since the scan lines are sequentially driven over time in order to drive, the instantaneous luminance must be equal to the average luminance multiplied by the number of lines in order to represent the required average luminance.

However, in the active matrix method, a thin film transistor (TFT), which is a switching element for turning on / off a pixel area, is positioned for each pixel area, and is connected to the switching thin film transistor and the driving thin film transistor is connected to the driving thin film transistor. It is connected to a power supply wiring and an organic light emitting diode and is formed for each pixel region.

In this case, a first electrode connected to the driving thin film transistor is turned on / off in a pixel area unit, and a second electrode facing the first electrode serves as a common electrode to be interposed between these two electrodes. Together with the organic light emitting layer, the organic light emitting diode is formed.

In the active matrix method having this characteristic, the voltage applied to the pixel region is charged in the storage capacitor Cst, and the power is applied until the next frame signal is applied. Run continuously during the screen.

Therefore, since low luminance, high definition, and large size can be obtained even when a low current is applied, an active matrix type organic light emitting diode is mainly used in recent years.

1 is a plan view schematically showing a flexible organic light emitting device according to the prior art.

2 is a schematic cross-sectional view of an organic light emitting diode according to the related art.

3 is an enlarged cross-sectional view of a portion “A” of FIG. 2 and is an enlarged cross-sectional view of a flexible organic light emitting diode according to the related art.

1 to 3, in the flexible organic light emitting diode 10 according to the related art, a display area AA is defined on a substrate 11, and a non-display area NA is disposed outside the display area AA. The display area AA includes a plurality of pixels P defined as regions captured by a gate line (not shown) and a data line (not shown), and the data line (not shown). Parallel to the power supply is provided (not shown).

Here, each of the plurality of pixels P is provided with a switching thin film transistor (not shown) and a driving thin film transistor (not shown).

Referring to the flexible organic light emitting device 10 according to the related art in detail, as shown in FIGS. 1 and 2, the display area AA is defined on the substrate 11, and the outside of the display area AA is defined. The non-display area NA is defined, and the display area AA includes a plurality of pixel areas P defined as areas captured by a gate line (not shown) and a data line (not shown). In addition, a power supply wiring (not shown) is provided in parallel with the data wiring (not shown).

Here, a plurality of switching thin film transistors STr and driving thin film transistors DTr are formed in the display area AA, and the switching transistor STr is included in the substrate 11 of the non-display area NA. Drive circuits are formed.

As shown in FIG. 3, the switching thin film transistor STr and the driving transistor DTr have the same configuration, and include the semiconductor layer 13 including the first, second, and third regions 13a, 13b, and 13c. The gate insulating film 15 and the gate electrode 17 formed on the gate insulating film 13 on the semiconductor layer 13 and the interlayer insulating film 19 formed on the gate insulating film 13 including the gate electrode 17. And a source electrode 21a and a drain electrode 21b formed on each other and spaced apart from each other.

The drain contact hole exposing the drain electrode 21b of the driving thin film transistor (not shown) is disposed on the driving thin film transistor (not shown) and the switching thin film transistor (not shown) formed in the display area AA. An interlayer insulating film 19 and planarization film 23 having a layer (not shown) are stacked.

In addition, the planarization layer 23 is in contact with the drain electrode 21b of the driving thin film transistor (not shown) through the drain contact hole (not shown), and has an separated shape for each pixel P. A first electrode 25 which is an anode is formed.

A bank 29 is formed on the first electrode 25 to separate the pixels P. In this case, the bank 29 is disposed between the pixels P adjacent to each other. In addition, the bank 29 is formed not only between adjacent pixels P, but a part 29 of the bank 29 is also formed in the outer portion of the panel, that is, the non-display area NA.

An organic emission layer 29 including an organic emission pattern (not shown) that emits red, green, and blue light is formed on the first electrode 25 in each pixel P surrounded by the bank 29.

In addition, a second electrode 31, which is a cathode, is formed on an entire surface of the display area AA on the organic emission layer 29 and the bank 27. In this case, the organic light emitting layer 29 interposed between the first electrode 25, the second electrode 31, and the two electrodes 25 and 31 forms an organic light emitting diode (E). In this case, driving circuits are disposed in the non-display area NA, for example, the bezel area, and the first electrode 25 as the anode electrode, the organic light emitting layer 29 and the second electrode 31 as the cathode electrode are disposed. It is not formed.

On the other hand, the first passivation film 33 is formed on the entire surface of the substrate including the second electrode 31 as an insulating film for preventing moisture permeation.

In addition, an organic layer 35 made of a polymer organic material such as a polymer is formed in the display area AA on the first passivation layer 33.

In addition, a second passivation layer 37 is further formed on the first passivation layer 33 including the organic layer 35 to block moisture from penetrating through the organic layer 35.

Furthermore, a barrier film (not shown) for preventing encapsulation and upper moisture permeation of the organic light emitting diode E is disposed on the front surface of the substrate including the second passivation layer 37. A pressure sensitive adhesive (hereinafter referred to as PSA) (not shown) is interposed between the substrate 11 and the protective film (not shown) to be in close contact with the substrate 11 and the protective film (not shown) without an air layer. have. At this time, the second passivation film 37, the pressure-sensitive adhesive (not shown) and the protective film (not shown) form a face seal (face seal) structure.

Thus, the substrate 11 and the protective film (barrier film) (not shown) are fixed by an adhesive (not shown) to form a panel state, thereby forming the organic light emitting device 10 according to the prior art.

4 is a schematic cross-sectional view when the flexible organic light emitting diode according to the prior art is bent.

Referring to FIG. 4, when the flexible organic light emitting diode 10 according to the related art is bent, a stress is generated at a point. In particular, since the planarization film 23 is uniformly formed with a uniform thickness all over the substrate 11, a phenomenon in which stress is concentrated in bending at the time of bending application for the flexible display occurs.

In particular, if the curvature is uniform in one panel, the deformation is also constant, so it is not a big problem, but if the plane and the curvature are in the light emitting area or if there are two or more curvatures, they are stressed depending on the position in the device.

As shown in FIG. 4, when the curvature is applied to only a part of the organic light emitting device 10 according to the related art, not a whole light emitting area, the stress is applied only to the indicated portion B. FIG.

5 is a cross-sectional view showing a crack occurring in the bent portion (B) of the organic light emitting device according to the prior art.

As shown in FIG. 5, cracks, etc., occur in the bent portion B to have a fatal effect on the screen.

As described above, in the case of the flexible organic light emitting device according to the related art, the thickness of the planarization layer is maintained uniformly. When bending is applied to implement the flexible display, stress is applied to a predetermined portion. Receives a fatal defect. In particular, in this process, if the curvature is applied only to a portion other than the light emitting area itself or has two or more curvatures in the light emitting area, the stress applied to a portion of the panel becomes more severe.

Accordingly, the present invention is to solve the problems of the prior art, an object of the present invention is to form a plurality of concave patterns having a radius of curvature in the planarization film to leave a difference in the thickness caused by bending (bending) The present invention provides a flexible organic electroluminescent device and a method of manufacturing the same, which have corrected a defect generated during bending.

According to an aspect of the present invention, there is provided a flexible organic light emitting display device, including: a display area including a plurality of pixel areas and a non-display area defined outside thereof; A plurality of thin film transistors formed in the pixel area and the non-display area on the substrate; A planarization film formed on an entire surface of the substrate including the thin film transistors and having at least one concave pattern having a radius of curvature; A first electrode formed on the planarization layer and connected to the thin film transistor of the display area; A bank formed around each pixel region of the substrate including the first electrode; An organic emission layer formed on each of the pixel areas above the first electrode; A second electrode formed on an entire surface of the substrate including the organic light emitting layer; A first passivation film formed on an entire surface of the substrate including the second electrode; An organic film formed on the first passivation film; A second passivation film formed on the organic film and the first passivation film; A protective film facing the substrate; And an adhesive interposed between the substrate and the protective film to form a panel state by adhering the substrate and the protective film.

According to an aspect of the present invention, there is provided a method of manufacturing a flexible organic light emitting device, including: providing a display area including a plurality of pixel areas and a substrate on which a non-display area is defined; Forming a plurality of thin film transistors in each of the pixel area and the non-display area on the substrate; Forming a planarization film having at least one concave pattern having a radius of curvature on the entire surface of the substrate including the thin film transistors; Forming a first electrode connected to the thin film transistor of the display area on the planarization layer; Forming a bank around each pixel region of the substrate including the first electrode; Forming an organic emission layer on each pixel area over the first electrode; Forming a second electrode over an entire display area of the substrate including the organic light emitting layer; Stacking a first passivation film, an organic film, and a second passivation film on an entire surface of the substrate including the second electrode; Forming a protective film facing the substrate; And interposing the adhesive between the substrate and the protective film to form a panel state by adhering the substrate and the protective film.

According to the flexible organic light emitting device according to the present invention and a method of manufacturing the same, a plurality of concave patterns are formed on the top surface of the planarization film to make thickness variations, thereby distributing the stresses to a certain portion in the panel through the variation of the thicknesses, thereby causing a fatal effect. Defects can be prevented in advance.

In addition, according to the flexible organic light emitting device according to the present invention and a method for manufacturing the same, one or more curvatures may be applied by forming at least one concave pattern only in a region where bending occurs a lot without forming concave patterns on the entire upper surface of the planarization film By doing so, it is possible to apply various flexible displays without major defects.

In addition, according to the flexible organic light emitting diode and the method of manufacturing the same, various flexible displays can be applied without significant defects during bending by forming concave patterns having different radii of curvature on the top surface of the planarization film.

1 is a plan view schematically showing a flexible organic light emitting device according to the prior art.
2 is a cross-sectional view schematically showing a flexible organic light emitting device according to the prior art.
3 is an enlarged cross-sectional view of a portion “A” of FIG. 2 and is an enlarged cross-sectional view of a flexible organic light emitting diode according to the related art.
4 is a schematic cross-sectional view when the flexible organic light emitting diode according to the prior art is bent.
5 is a cross-sectional view showing a crack occurring in the bent portion (B) of the organic light emitting device according to the prior art.
6 is a plan view schematically showing a flexible organic light emitting device according to the present invention.
FIG. 7 is a cross-sectional view taken along line VII-VII of FIG. 6, and schematically illustrates a flexible organic light emitting diode according to the present invention.
FIG. 8 is an enlarged cross-sectional view of a portion “C” of FIG. 7 and is an enlarged cross-sectional view of the flexible organic light emitting device according to the present invention.
9 is a schematic cross-sectional view when the flexible organic light emitting diode according to the present invention is bent.
10A to 10J are cross-sectional views illustrating a process of manufacturing the flexible organic light emitting diode according to the present invention.

Hereinafter, a flexible organic light emitting diode according to an exemplary embodiment of the present invention will be described in detail with reference to the accompanying drawings.

The organic light emitting device according to the present invention is divided into a top emission type and a bottom emission type according to the transmission direction of the emitted light. Hereinafter, the top emission method will be described as an example. would.

6 is a plan view schematically showing a flexible organic light emitting device according to the present invention.

FIG. 7 is a cross-sectional view taken along line VII-VII of FIG. 6, and schematically illustrates a flexible organic light emitting diode according to the present invention.

FIG. 8 is an enlarged cross-sectional view of a portion “C” of FIG. 7 and is an enlarged cross-sectional view of the flexible organic light emitting device according to the present invention.

6 to 8, the organic light emitting diode 100 according to the present invention includes a substrate in which a display area AA including a plurality of pixels P and a non-display area NA are defined outside thereof. 101); A switching thin film transistor (not shown) and a driving thin film transistor DTr formed in each of the pixels P on the substrate 101; A planarization film formed on an entire surface of the substrate 101 including the switching thin film transistor and the driving thin film transistor DTr and having at least one concave pattern 119 having a radius of curvature; A first electrode 121 formed on the planarization film 115 and connected to the drain electrode 113b of the driving thin film transistor DTr; A bank 123 formed around each pixel P of the substrate including the first electrode 121; An organic emission layer 125 formed on each of the pixels P on the first electrode 121; A second electrode 127 formed on an entire surface of the substrate including the organic emission layer 125; A first passivation film 129 formed on the entire surface of the substrate including the second electrode 127; An organic layer 131 formed on the first passivation layer 129; And a second passivation layer 133 formed on the organic layer 131 and the first passivation layer 129.

Referring to the organic light emitting device 100 according to the present invention in detail, as shown in FIG. 6, a display area AA is defined in the substrate 101, and the display area AA is outside the display area AA. A display area NA is defined, and the display area AA includes a plurality of pixel areas P defined as areas captured by a gate line (not shown) and a data line (not shown). Power supply wiring (not shown) is provided in parallel with the data wiring (not shown).

Here, a plurality of switching thin film transistors (not shown) and driving thin film transistors DTr are formed in the display area AA.

A glass substrate or a flexible substrate may be used as the substrate 101. The flexible substrate may have a flexible characteristic to maintain display performance even when a flexible organic light emitting diode (OLED) is bent like a paper. Made of flexible glass substrate or plastic material.

7 and 8, a buffer layer (not shown) made of an insulating material, for example, silicon oxide (SiO ₂ ) or silicon nitride (SiNx), which is an inorganic insulating material, is formed on the substrate 101. At this time, the reason why the buffer layer (not shown) is formed below the semiconductor layer 103 formed in a subsequent process is due to the release of alkali ions emitted from the inside of the substrate 101 during crystallization of the semiconductor layer 103. This is to prevent deterioration of the characteristics of the semiconductor layer 103.

In addition, each pixel P in the display area AA on the buffer layer (not shown) is made of pure polysilicon corresponding to the driving area (not shown) and the switching area (not shown), and the center portion thereof A semiconductor layer 103 including a first region 103a constituting a channel and second regions 103b and 103c doped with a high concentration of impurities is formed on both sides of the first region 103a.

A gate insulating layer 105 is formed on the buffer layer including the semiconductor layer 103, and the semiconductor layer 103 is disposed above the gate insulating layer 105 in the driving region (not shown) and the switching region (not shown). The gate electrode 107 is formed to correspond to the first region 103a of.

In addition, the gate insulating layer 105 is connected to the gate electrode 107 formed in the switching region (not shown) and extends in one direction to form a gate wiring (not shown). In this case, the gate electrode 107 and the gate wiring (not shown) is a first metal material having low resistance, for example, aluminum (Al), aluminum alloy (AlNd), copper (Cu), copper alloy, molybdenum ( Mo) may be made of any one of the molybdenum (MoTi) may have a single layer structure, or may be made of two or more of the first metal material to have a double layer or triple layer structure. In the drawing, the gate electrode 107 and the gate wiring (not shown) are illustrated as one example.

Meanwhile, an interlayer insulating layer made of an insulating material, for example, silicon oxide (SiO ₂ ) or silicon nitride (SiNx), which is an inorganic insulating material on the entire display area of the substrate including the gate electrode 107 and the gate wiring (not shown). 109 is formed. In this case, a semiconductor exposing each of the second regions 103b and 103c positioned on both sides of the first region 103a of each semiconductor layer 103 in the interlayer insulating layer 109 and the gate insulating layer 105 under the interlayer insulating layer 109. A layer contact hole (not shown) is provided.

An upper portion of the interlayer insulating layer 109 including the semiconductor layer contact hole (not shown) intersects with the gate wiring (not shown), defines the pixel region P, and defines a second metal material, for example, aluminum ( Al), aluminum alloy (AlNd), copper (Cu), copper alloy, molybdenum (Mo), molybdenum (MoTi), chromium (Cr), titanium (Ti) or a data wiring made of one or more materials (not shown) ) And a power supply wiring (not shown) are formed apart from each other. In this case, the power line (not shown) may be formed in parallel with the gate line (not shown) on the layer on which the gate line (not shown) is formed, that is, the gate insulating layer 105.

As shown in FIG. 8, each of the driving region (not shown) and the switching region (not shown) on the interlayer insulating layer 109 are spaced apart from each other and exposed through the semiconductor layer contact hole (not shown). A source electrode 113a and a drain electrode 113b are formed in contact with the 103b and 103c and made of the same second metal material as the data line (not shown). In this case, the semiconductor layer 103, the gate insulating layer 105, and the gate electrode 107 and the interlayer insulating layer 109 that are sequentially stacked in the switching region (not shown) and the driving region (not shown) are formed to be spaced apart from each other. The source electrode 113a and the drain electrode 113b form a driving thin film transistor DTr.

In the drawings, the data wiring (not shown), the source electrode 113a and the drain electrode 113b all have a single layer structure, but these components may form a double layer or triple layer structure. have.

In this case, although not shown in the drawing, a switching thin film transistor (not shown) having the same stacked structure as the driving thin film transistor DTr is also formed in the switching region (not shown). In this case, the switching thin film transistor (not shown) is electrically connected to the driving thin film transistor DTr, the gate line (not shown), and the data line (not shown). That is, the gate line (not shown) and the data line (not shown) are respectively connected to the gate electrode (not shown) and the source electrode (not shown) of the switching thin film transistor (not shown), the switching thin film transistor ( The drain electrode of the driving thin film transistor DTr is electrically connected to the gate electrode 107 of the driving thin film transistor DTr.

Meanwhile, although the driving thin film transistor DTr and the switching thin film transistor (not shown) have a semiconductor layer 103 of polysilicon and are configured as a top gate type, the driving switching thin film transistor is shown as an example. It is apparent that the DTr and the switching thin film transistor (not shown) may be configured as a bottom gate type having a semiconductor layer of amorphous silicon.

When the driving thin film transistor DTr and the switching thin film transistor have a bottom gate type, the stacked structure is a semiconductor spaced apart from an active layer of a gate electrode / gate insulating film / pure amorphous silicon and an ohmic contact layer of impurity amorphous silicon. And a source electrode and a drain electrode spaced apart from the layer. In this case, the gate line is formed to be connected to the gate electrode of the switching thin film transistor on the layer where the gate electrode is formed, and the data line is formed to be connected to the source electrode on the layer where the source electrode of the switching thin film transistor is formed.

Meanwhile, a planarization film 115 including at least one concave pattern 119 having a radius of curvature is formed on the front surface of the substrate including the driving thin film transistor DTr and the switching thin film transistor (not shown) of the display area AA. It is. In this case, the planarization layer 115 may include an insulating material, for example, an inorganic insulating material including silicon oxide (SiO ₂ ) and silicon nitride (SiNx), or an organic insulating material including photo-acyl. Any one of the materials is selected and used. In addition, the at least one concave pattern 119 formed in the planarization film 115 may have the same radius of curvature or may have a different radius of curvature. In addition, at least one concave pattern 119 may be formed in the planarization layer 115 corresponding to a region to be bent much during bending of the panel. In this case, the planarization film 115 is formed with concave patterns 119 having a radius of curvature, whereby planes and curved surfaces are formed. In the present invention, an example of the planarization film 115 having a plurality of concave patterns 119 having the same radius of curvature will be described.

In addition, a drain contact hole (not shown) for electrically contacting the drain electrode 113b with the first electrode 121 formed in a subsequent process is formed in the planarization film 115 corresponding to the display area of the substrate 101. Is formed.

In addition, the planarization layer 115 is in contact with the drain electrode 113b of the driving thin film transistor DTr through the drain contact hole (not shown), and has a shape separated from each pixel area P. One electrode 121 is formed.

In addition, the first electrode 121 is formed of an insulating material, for example, bensocyclobutene (BCB), polyimide, or photo acryl to separately define each pixel P. The bank 123 is formed. In this case, the bank 123 is formed to overlap the edge of the first electrode 121 in a form surrounding each pixel P, and forms a lattice having a plurality of openings as a whole of the display area AA. have. The bank 123 is also formed in the non-display area NA, which is an outer portion of the panel.

On the other hand, an organic light emitting layer 125 including an organic light emitting pattern (not shown) emitting red, green, and blue light is formed on the first electrode 121 in each pixel P surrounded by the bank 123. have. The organic light emitting layer 125 may be composed of a single layer made of an organic light emitting material or, although not shown in the drawing, in order to increase light emission efficiency, a hole injection layer, a hole transporting layer, and a light emitting material layer (emitting material layer), an electron transporting layer (electron transporting layer) and an electron injection layer (electron injection layer) may be composed of multiple layers.

In addition, a second electrode 127 is formed in the display area AA of the substrate including the organic emission layer 125 and the bank 123. In this case, the organic light emitting layer 125 interposed between the first electrode 121 and the second electrode 127 and the two electrodes 121 and 127 forms an organic light emitting diode (E).

Accordingly, when a predetermined voltage is applied to the first electrode 121 and the second electrode 127 according to the selected color signal, the organic light emitting diode E may have holes and second holes injected from the first electrode 121. Electrons provided from the electrode 127 are transported to the organic light emitting layer 125 to form excitons, and when such excitons transition from the excited state to the ground state, light is generated and emitted in the form of visible light. In this case, since the emitted light passes through the transparent second electrode 127 to the outside, the organic light emitting diode 100 implements an arbitrary image.

On the other hand, a first passivation film 129 made of an insulating material, in particular an inorganic insulating material, silicon oxide (SiO ₂ ) or silicon nitride (SiNx) is formed on the entire surface of the substrate including the second electrode 127. In this case, since the penetration of moisture into the organic light emitting layer 125 cannot be completely suppressed by the second electrode 127 alone, the organic light emitting layer is formed by forming the first passivation layer 129 on the second electrode 127. It is possible to completely suppress the water penetration into 127.

In addition, an organic layer 131 formed of a polymer organic material such as a polymer is formed on the first passivation layer 129. In this case, the polymer thin film constituting the organic layer 131 may be an olefin-based polymer (polyethylene, polypropylene), polyethylene terephthalate (PET), epoxy resin, fluoro resin, polysiloxane, or the like. This can be used.

In addition, an entire surface of the substrate including the organic layer 131 and the first passivation layer 129 may be formed of an insulating material, for example, an inorganic insulating material, such as silicon oxide, to block moisture from penetrating through the organic layer 131. A second passivation film 133 made of SiO ₂ ) or silicon nitride (SiNx) is further formed.

Although not shown in the drawings, a protective film (not shown) is disposed on the front surface of the substrate including the second passivation layer 133 so as to encapsulate the organic light emitting diode (E). Between the protective film (not shown), a pressure-sensitive adhesive (not shown) made of any one of a frit, an organic insulating material, and a polymer material, which is transparent and has adhesive properties, has no air layer, and the substrate 101 and the barrier film. It is closely interposed with (not shown). In this case, in the present invention, a case using PSA (Press Sensitive Adhesive) as the adhesive (not shown) will be described as an example.

As described above, the substrate 101 and the barrier film (not shown) are fixed by the adhesive 137 to form a panel, thereby forming the organic light emitting device 100 according to the present invention.

9 is a schematic cross-sectional view when the flexible organic light emitting diode according to the present invention is bent.

Referring to FIG. 9, when the flexible organic light emitting diode 100 is bent, stress is applied to the bent portion, but the concave pattern 119 having a radius of curvature is applied to the planarization film 115. Are formed so that the stress applied to a certain portion, that is, the bent portion, is dispersed. Although the flexible organic electroluminescent device 100 is bent, the concave pattern 119 formed in the planarization film 115 has a radius of curvature, thereby distributing a certain amount of stress due to bending. In this case, the concave pattern 119 having the radius of curvature may be formed to correspond to a portion of the planarization film 115 corresponding to the region where the panel is bent, or may be formed on the planarization layer 115 regardless of the region where the panel is bent. By forming one or more concave patterns 115 having a radius of curvature, various flexible displays may be implemented.

  Therefore, according to the flexible organic light emitting device according to the present invention, by forming a plurality of concave patterns on the top surface of the planarization film to make a thickness variation, the stress caused by a certain portion in the panel is dispersed through this thickness variation to cause fatal defects Can be blocked in advance.

In addition, according to the flexible organic light emitting device according to the present invention, at least one concave pattern may be formed only in a region where bending occurs a lot, and thus at least one curvature may be applied without forming concave patterns on the entire upper surface of the planarization film. Various flexible displays can be applied without major defects.

In addition, according to the flexible organic light emitting device according to the present invention, by forming concave patterns having different radii of curvature on the top surface of the planarization layer, various flexible displays can be applied without significant defects during bending.

Meanwhile, a method of manufacturing the flexible organic light emitting diode according to the present invention will be described with reference to FIGS. 10A to 10J.

10A through 10J are cross-sectional views schematically illustrating a method of manufacturing an organic light emitting diode according to the present invention.

As shown in FIG. 10A, a substrate 101 having a display area AA and a non-display area NA defined outside the display area AA is prepared. In this case, the substrate 101 may be a glass substrate or a flexible substrate. The flexible substrate may be flexible to maintain display performance even when the flexible organic light emitting diode (OLED) is bent like paper. It is made of flexible glass substrate or plastic material.

Next, a buffer layer (not shown) made of an insulating material, for example, silicon oxide (SiO ₂ ) or silicon nitride (SiNx), which is an inorganic insulating material, is formed on the substrate 101. At this time, the reason why the buffer layer (not shown) is formed below the semiconductor layer 103 formed in a subsequent process is due to the release of alkali ions emitted from the inside of the substrate 101 during crystallization of the semiconductor layer 103. This is to prevent deterioration of the characteristics of the semiconductor layer 103.

Subsequently, each pixel area P in the display area AA on the buffer layer (not shown) corresponds to the driving circuit part of the driving area (not shown) and the switching area (not shown) and the non-display area NA. Each of the semiconductor layers may be made of pure polysilicon, and the center portion may include a first region 103a constituting a channel and second regions 103b and 103c doped with a high concentration of impurities on both sides of the first region 103a. 103).

Next, a gate insulating film 105 is formed on the buffer layer including the semiconductor layer 103, and each of the semiconductors is formed in the driving region (not shown) and the switching region (not shown) on the gate insulating film 105. The gate electrode 107 is formed corresponding to the first region 103a of the layer 103.

In addition, the gate insulating layer 105 is connected to the gate electrode 107 formed in the switching region (not shown) and extends in one direction to form a gate wiring (not shown). In this case, the gate electrode 107 and the gate wiring (not shown) is a first metal material having low resistance, for example, aluminum (Al), aluminum alloy (AlNd), copper (Cu), copper alloy, molybdenum ( Mo) may be made of any one of the molybdenum (MoTi) may have a single layer structure, or may be made of two or more of the first metal material to have a double layer or triple layer structure. In the drawing, the gate electrode 107 and the gate wiring (not shown) are illustrated as one example.

Next, as shown in FIG. 10B, an insulating material, for example, an inorganic insulating material, such as silicon oxide (SiO ₂ ) or silicon nitride (SiNx) is formed on the entire surface of the substrate including the gate electrode 107 and the gate wiring (not shown). An insulating film 109 is formed.

Subsequently, the insulating layer 109 and the gate insulating layer 105 below are selectively patterned to expose each of the second regions 103b and 103c located on both sides of the first region 103a of the semiconductor layer. A semiconductor layer contact hole (not shown) is formed.

Next, although not shown in the figure, a metal material crossing the gate wiring (not shown) on the interlayer insulating layer 109 including the semiconductor layer contact hole (not shown) and defining the pixel region P. Form a layer (not shown). In this case, the metal material layer (not shown) is aluminum (Al), aluminum alloy (AlNd), copper (Cu), copper alloy, molybdenum (Mo), molybdenum (MoTi), chromium (Cr), titanium (Ti) As one or more than two materials.

Subsequently, the metal material layer (not shown) is selectively patterned to intersect with the gate wiring (not shown), and the data wiring (not shown) and the data driving circuit wiring (not shown) defining the pixel area P are formed. And, apart from this to form a power wiring (not shown). In this case, the power line (not shown) may be formed in parallel with the gate line (not shown) on the layer where the gate line (not shown) is formed, that is, the gate insulating layer.

When the data line is formed, the insulating layer 109 is spaced apart from each other in the driving region (not shown) and the switching region (not shown) and exposed through the semiconductor layer contact hole (not shown). Contacting the second regions 103b and 103c, respectively, and simultaneously forming a source electrode 113a and a drain electrode 113b made of the same metal material as the data line (not shown). In this case, the source electrode 113a formed to be spaced apart from the semiconductor layer 103, the gate insulating layer 105, the gate electrode 107, and the interlayer insulating layer 109 sequentially stacked in the driving region (not shown), and The drain electrode 113b forms a driving thin film transistor DTr.

In the drawings, the data wiring (not shown), the source electrode 113a, and the drain electrode 113b all have a single layer structure, but these components may form a double layer or triple layer structure. have.

In this case, a switching thin film transistor (not shown) having the same stacked structure as the driving thin film transistor DTr is also formed in the driving circuit portion of the switching area (not shown) and the non-display area NA of the display area AA. . In this case, the switching thin film transistor (not shown) of the display area NA is electrically connected to the driving thin film transistor DTr, the gate line (not shown), and the data line 113. That is, the gate line (not shown) and the data line (not shown) are respectively connected to the gate electrode (not shown) and the source electrode (not shown) of the switching thin film transistor (not shown), the switching thin film transistor ( The drain electrode of the driving thin film transistor DTr is electrically connected to the gate electrode 107 of the driving thin film transistor DTr.

Meanwhile, the driving thin film transistor DTr, the switching thin film transistor (not shown), and the switching thin film transistor (not shown) of the non-display area NA have a semiconductor layer 103 of polysilicon, and have a top gate type (Top gate). type), the driving switching thin film transistor DTr and the switching thin film transistor (not shown) may be configured as a bottom gate type having a semiconductor layer of amorphous silicon. .

When the driving thin film transistor DTr and the switching thin film transistor (not shown) have a bottom gate type, the stacked structure is spaced apart from the active layer of the gate electrode / gate insulating film / pure amorphous silicon and is an ohmic contact of impurity amorphous silicon. The semiconductor layer is composed of a layer and a source electrode and a drain electrode spaced apart from each other. In this case, the gate line is formed to be connected to the gate electrode of the switching thin film transistor on the layer where the gate electrode is formed, and the data line is formed to be connected to the source electrode on the layer where the source electrode of the switching thin film transistor is formed.

Next, as shown in FIG. 10C, the planarization film 115 is disposed on the driving thin film transistor DTr, the switching thin film transistor (not shown), and the switching thin film transistor STr in the driving circuit portion of the non-display area NA. To form. In this case, the planarization layer 115 may include an insulating material, for example, an inorganic insulating material including silicon oxide (SiO ₂ ) and silicon nitride (SiNx), or an organic insulating material including photo-acyl. Any one of the materials is selected and used. In the present invention, the case where the planarization film 115 is formed using an organic insulating material will be described as an example.

Subsequently, as shown in FIG. 10D, the planarization film 115 is selectively patterned after exposure and development using a half-tone mask (not shown), which is a diffraction mask, to form the substrate. A drain contact hole for electrically contacting the drain electrode 113b with a first electrode (not shown in FIG. 10E) (see FIG. 10E) formed in the planarization film 115 corresponding to the display area of 101 may be electrically contacted with the drain electrode 113b. Together with 117, a plurality of concave patterns 119 having a radius of curvature are formed. In this case, since the planarization film 115 is made of an organic insulating material exhibiting photosensitivity, a layer such as a photoresist may not be formed during the exposure process. In addition, as a diffraction mask, a slit mask or a mask using other diffraction characteristics may be used in addition to the half-tone mask (not shown).

During the exposure process using the halftone mask (not shown), a separate light blocking film pattern (not shown) is formed on the halftone mask (not shown) corresponding to the portion of the planarization film 115 where the drain contact hole 117 is to be formed. Is not formed, and a semi-transmissive pattern (not shown) is formed in the halftone mask (not shown) corresponding to the portion of the planarization film 115 where the concave pattern 119 is to be formed. At this time, during the exposure process using the halftone mask, light passes directly through a halftone mask (not shown) corresponding to a portion of the planarization film 115 where the drain contact hole 117 is to be formed, thereby allowing the planarization film ( The light is transflected through the light blocking pattern (not shown) of the halftone mask (not shown) that is transmitted through the light source 115 and corresponds to the portion of the planarization film 115 where the concave pattern 119 is to be formed. Through the post-development process, concave patterns 119 having a radius of curvature are formed in the planarization film 115 together with the drain contact hole 117. However, as the method of forming the concave patterns 119 having the radius of curvature of the drain contact hole 117, an exposure method other than the exposure method using the halftone mask may be used.

Meanwhile, the at least one concave pattern 119 formed on the planarization film 115 may have the same radius of curvature or may have a different radius of curvature. In addition, at least one concave pattern 119 may be formed in the planarization layer 115 corresponding to a region to be bent much during bending of the panel. In this case, the planarization film 115 is formed with concave patterns 119 having a radius of curvature, whereby planes and curved surfaces are formed. In the present invention, a case of forming a plurality of concave patterns 119 having the same radius of curvature in the planarization film 115 will be described as an example.

Next, as shown in FIG. 10E, a metal material layer (not shown) is deposited on the entire surface of the substrate including the planarization film 115, and then the metal material layer is selectively patterned to form the planarization film 115. The first contact 121 contacts the drain electrode 113b of the driving thin film transistor DTr through the drain contact hole 117 and forms a first electrode 121 having a separate shape for each pixel region P. Referring to FIG. In this case, the metal material layer (not shown) is aluminum (Al), aluminum alloy (AlNd), copper (Cu), copper alloy, molybdenum (Mo), molybdenum (MoTi), chromium (Cr), titanium (Ti) As one or more than two materials.

Subsequently, as illustrated in FIG. 10F, an insulating material, for example, bensocyclobutene (BCB) and polyimide, is disposed on the boundary of each pixel P and the non-display area NA on the first electrode 121. A bank 123 formed of poly-imide or photo acryl is formed. In this case, the bank 123 is formed to overlap the edge of the first electrode 121 to surround each pixel area P, and has a lattice shape having a plurality of openings as a whole of the display area AA. It is coming true. In addition, the bank 123 may be formed in the non-display area NA, which is an outer portion of the panel.

Next, as shown in FIG. 10G, an organic light emitting pattern (not shown) that emits red, green, and blue colors is disposed on the first electrode 121 in each pixel P surrounded by the bank 123, respectively. The configured organic light emitting layer 125 is formed. The organic light emitting layer 125 may be composed of a single layer made of an organic light emitting material or, although not shown in the drawing, in order to increase light emission efficiency, a hole injection layer, a hole transporting layer, and a light emitting material layer (emitting material layer), an electron transporting layer (electron transporting layer) and an electron injection layer (electron injection layer) may be composed of multiple layers.

Subsequently, as shown in FIG. 10H, a transparent conductive material layer (not shown) made of any one of transparent conductive materials including, for example, ITO and IZO, on the entire surface of the substrate including the organic light emitting layer 125 and the bank 123. ) Is deposited and then selectively patterned to form the second electrode 127 in the display area AA of the substrate including the organic emission layer 125 and the bank 123. In this case, the organic light emitting layer 125 interposed between the first electrode 121 and the second electrode 127 and the two electrodes 121 and 127 forms an organic light emitting diode (E).

Accordingly, when a predetermined voltage is applied to the first electrode 121 and the second electrode 127 according to the selected color signal, the organic light emitting diode E may have holes and second holes injected from the first electrode 121. Electrons provided from the electrode 127 are transported to the organic light emitting layer 125 to form excitons, and when such excitons transition from the excited state to the ground state, light is generated and emitted in the form of visible light. In this case, since the emitted light passes through the transparent second electrode 127 to the outside, the organic light emitting diode 100 implements an arbitrary image.

Next, as illustrated in FIG. 10I, a first passivation film (eg, silicon oxide (SiO ₂ ) or silicon nitride (SiNx), which is an insulating material, particularly an inorganic insulating material, may be formed on the entire surface of the substrate including the second electrode 127. 129). In this case, since the penetration of moisture into the organic light emitting layer 125 cannot be completely suppressed by the second electrode 127 alone, the organic light emitting layer is formed by forming the first passivation layer 129 on the second electrode 127. It is possible to completely suppress the water penetration into the 125.

Next, as shown in FIG. 10J, an organic layer 131 made of a polymer organic material such as a polymer is formed in the display area AA on the first passivation layer 129. In this case, the polymer thin film constituting the organic layer 131 may be an olefin-based polymer (polyethylene, polypropylene), polyethylene terephthalate (PET), epoxy resin, fluoro resin, polysiloxane, or the like. This can be used.

Next, silicon oxide, which is an insulating material, for example, an inorganic insulating material, to block moisture from penetrating through the organic film 133 on the entire surface of the substrate including the organic film 131 and the first passivation film 129. A second passivation film 133 made of (SiO ₂ ) or silicon nitride (SiNx) is further formed.

Subsequently, although not shown in the drawings, a protective film (not shown) is disposed to face the substrate including the second passivation layer 133 so as to encapsulate the organic light emitting diode E. The substrate 101 and the protective layer without an air layer through an adhesive (not shown) made of any one of a frit, an organic insulating material, and a polymer material, which is transparent and has an adhesive property between the protective film (not shown). By forming the film (not shown) to be in close contact, the process of manufacturing the flexible organic light emitting device 100 according to the present invention is completed. In this case, the present invention will be described by taking an example of using a pressure sensitive adhesive (PSA) as the pressure-sensitive adhesive (not shown).

Thus, the substrate 101 and the barrier film (not shown) are fixed by an adhesive (not shown) to form a panel state.

Therefore, according to the method of manufacturing the flexible organic light emitting device according to the present invention, by forming a plurality of concave patterns on the top surface of the planarization film to make a thickness deviation, the stress received at a certain part in the panel through the deviation of the thickness is fatal Defects can be prevented in advance.

In addition, according to the method of manufacturing the flexible organic light emitting device according to the present invention, one or more curvatures may be applied by forming at least one concave pattern only in a region where bending occurs a lot without forming concave patterns on the entire upper surface of the planarization film. By doing so, various flexible displays can be applied without major defects.

In addition, according to the method of manufacturing the flexible organic light emitting device according to the present invention, by forming concave patterns having different radii of curvature on the top surface of the planarization film, various flexible displays can be applied without significant defects during bending.

Those skilled in the art to which the present invention pertains will understand that the above-described present invention can be implemented in other specific forms without changing the technical spirit or essential features.

Therefore, it is to be understood that the embodiments described above are exemplary in all respects and not restrictive. The scope of the present invention is shown by the following claims rather than the detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts should be construed as being included in the scope of the present invention. do.

101: substrate 103: semiconductor layer
103a: first region 103b, 103c: second region
105: gate insulating film 107: gate electrode
109: interlayer insulating film 113a: source electrode
113b: drain electrode 115: planarization film
117: drain contact hole 119: concave pattern
121: first electrode 123: bank
125: organic light emitting layer 127: second electrode
129: first passivation film 131: organic film
133: second passivation film AA: display area
NA: non-display area P: pixel area

Claims (9)

A substrate having a display area including a plurality of pixel areas and a non-display area outside thereof, and having at least one bending part provided over at least a plurality of pixel areas;
A plurality of thin film transistors formed in the pixel area and the non-display area on the substrate;
A concave pattern formed on an entire surface of the substrate including the thin film transistors and overlapping the thin film transistors over a plurality of pixel regions corresponding to the bending part and having a radius of curvature on a surface; Planarization film;
A first electrode connected to the thin film transistor in the display area and formed on the planarization layer;
A bank covering a surface of the planarization film having concave patterns exposed from the first electrode and an edge of the first electrode and formed around each pixel region of the substrate;
An organic emission layer formed on each of the pixel areas above the first electrode;
A second electrode formed on an entire surface of the substrate including the organic light emitting layer;
A first passivation film formed on an entire surface of the substrate including the second electrode;
An organic film formed on the first passivation film; And
And a second passivation film formed on the organic film and the first passivation film. The flexible organic light emitting device of claim 1, wherein the at least one concave pattern has the same radius of curvature or has a different radius of curvature. The flexible organic electroluminescent device according to claim 1, wherein an upper surface of the planarization film includes only a flat portion corresponding to the non-bending portion. The flexible organic electroluminescent device according to claim 1, wherein the substrate is made of any one selected from a flexible glass substrate and a plastic material. Providing a substrate having a display area including a plurality of pixel areas and a non-display area outside thereof, the substrate having at least one bending portion over at least a plurality of pixel areas;
Forming a plurality of thin film transistors in each of the pixel area and the non-display area on the substrate;
Flattening the front surface of the substrate including the thin film transistors, the concave patterns having a radius of curvature on the surface and overlapping the thin film transistors over a plurality of pixel regions corresponding to the bending portion, and a planar portion between the concave patterns. Forming a film;
Forming a first electrode connected to the thin film transistor of the display area on the planarization layer;
Forming a bank around each pixel region of the substrate, covering the concave patterns exposed from the first electrode and the edge of the first electrode;
Forming an organic emission layer on each pixel area over the first electrode;
Forming a second electrode over an entire display area of the substrate including the organic light emitting layer; And
Stacking a first passivation film, an organic film, and a second passivation film on the entire surface of the substrate including the second electrode; and manufacturing the flexible organic light emitting device. The method of claim 5, wherein the at least one concave pattern has the same radius of curvature or has a different radius of curvature. The method of claim 5, wherein the top surface of the planarization film includes only a flat portion corresponding to the non-bending portion. The method of claim 5, wherein the forming of the concave patterns in the planarization layer comprises using a diffraction mask including a halftone mask. The method of claim 5, wherein the substrate is formed of any one selected from a flexible glass substrate and a plastic material.

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