KR102409120B1 - Organic light emitting display device - Google Patents

Abstract

An organic light emitting diode display according to the present invention includes a transistor and an organic light emitting diode connected to the transistor. The organic light emitting diode includes a first electrode. The first electrode includes a reflective layer and a transparent functional layer. The transparent functional layer is disposed on the reflective layer, and one end thereof protrudes further outward than one end of the reflective layer.

Description

Organic light emitting display device {ORGANIC LIGHT EMITTING DISPLAY DEVICE}

The present invention relates to an organic light emitting display device.

Various display devices capable of reducing weight and volume, which are disadvantages of a cathode ray tube, are being developed. Such display devices include a liquid crystal display (LCD), a field emission display (FED), a plasma display panel (PDP), and an organic light emitting display device (OLED). ) can be implemented as

Among these display devices, the organic light emitting display device is a self-luminous display device that emits light by excitation of an organic compound, and it does not require a backlight used in LCDs, so it can be lightweight and thin and has the advantage of simplifying the process. In addition, the organic light emitting display device is widely used in that it can be manufactured at a low temperature, has a high response speed with a response speed of 1 ms or less, and has characteristics such as low power consumption, wide viewing angle, and high contrast. have.

The organic light emitting diode display includes an organic light emitting diode that converts electric energy into light energy. The organic light emitting diode includes an anode, a cathode, and an organic compound layer disposed therebetween. In the organic light emitting display device, holes and electrons respectively injected from an anode and a cathode combine in an emission layer to form excitons, which are excitons, and the formed excitons are converted from an excited state to a ground state. As it falls, it emits light to display an image.

The organic compound layer may include red (R), green (G) and blue (B) organic compound layers, which may be formed in corresponding red (R), green (G) and blue (B) pixels, respectively. For such red (R), green (G), and blue (B) pixel patterning, a fine metal mask (FMM) is generally used. However, despite the rapid development of process technology, there is a limit to using the FMM mask to implement a high-resolution display device. In fact, when an FMM mask is used to implement a resolution of 1000 PPI or higher, it is difficult to secure a process yield of a certain level or higher.

In addition, in order to realize a large-area high-resolution display device, a corresponding large-area FMM mask is required. Various defects are caused, such as failure to do so.

The present invention provides an organic light emitting display device having improved display quality by minimizing color mixing defects.

An organic light emitting diode display according to the present invention includes a transistor and an organic light emitting diode connected to the transistor. The organic light emitting diode includes a first electrode. The first electrode includes a reflective layer and a transparent functional layer. The transparent functional layer is disposed on the reflective layer, and one end thereof protrudes further outward than one end of the reflective layer.

The present invention has an advantage in that color mixing defects can be minimized by controlling the area of the reflective layer constituting the reflective electrode. Accordingly, the present invention can prevent a problem in which the color reproducibility is significantly lowered, and thus can provide an organic light emitting display device with significantly improved display quality.

1 is a block diagram schematically illustrating an organic light emitting display device according to the present invention.
FIG. 2 is a configuration diagram schematically illustrating the pixel shown in FIG. 1 .
3 is a configuration diagram illustrating a specific example of FIG. 2 .
4 is a plan view schematically illustrating two neighboring pixels of an organic light emitting diode display according to an exemplary embodiment of the present invention.
FIG. 5 is a cross-sectional view taken along line II′ of FIG. 4 .
6 is a cross-sectional view taken along II-II′ of FIG. 4 .
7 and 8 are diagrams for explaining the problems of the related art and the contrast effect of the present invention.
9 is a flowchart showing a process for forming the first electrode of the present invention.
10 is a view for explaining a comparison between the first electrode manufacturing method and the general manufacturing method according to a preferred embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. Like reference numerals refer to substantially identical elements throughout. In the following description, if it is determined that a detailed description of a known technology or configuration related to the present invention may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted. In describing various embodiments, the same components are representatively described in the introduction and may be omitted in other embodiments.

Terms including an ordinal number such as 1st, 2nd, etc. may be used to describe various elements, but the elements are not limited by the terms. The above terms are used only for the purpose of distinguishing one component from another.

1 is a block diagram schematically illustrating an organic light emitting display device according to the present invention. FIG. 2 is a configuration diagram schematically illustrating the pixel shown in FIG. 1 . 3 is a configuration diagram illustrating a specific example of FIG. 2 .

Referring to FIG. 1 , the organic light emitting diode display 10 according to the present invention includes a display driving circuit and a display panel DIS.

The display driving circuit includes the data driving circuit 12 , the gate driving circuit 14 , and the timing controller 16 to write the video data voltage of the input image to the pixels Pix of the display panel DIS. The data driving circuit 12 converts digital video data RGB input from the timing controller 16 into an analog gamma compensation voltage to generate a data voltage. The data voltage output from the data driving circuit 12 is supplied to the data lines D1 to Dm. The gate driving circuit 14 sequentially supplies a gate signal synchronized with the data voltage to the gate lines G1 to Gn to select pixels Pix of the display panel DIS to which the data voltage is written.

The timing controller 16 inputs timing signals such as a vertical synchronization signal Vsync, a horizontal synchronization signal Hsync, a data enable signal DE, and a main clock MCLK input from the host system 19 . In response, the operation timings of the data driving circuit 12 and the gate driving circuit 14 are synchronized. The data timing control signal for controlling the data driving circuit 12 includes a source sampling clock (SSC), a source output enable signal (SOE), and the like. The gate timing control signal for controlling the gate driving circuit 14 includes a gate start pulse (GSP), a gate shift clock (GSC), a gate output enable signal (Gate Output Enable, GOE), etc. includes

The host system 19 may be implemented as any one of a television system, a set-top box, a navigation system, a DVD player, a Blu-ray player, a personal computer (PC), a home theater system, and a phone system. The host system 19 includes a system on chip (SoC) having a built-in scaler and converts digital video data RGB of an input image into a format suitable for display on the display panel DIS. The host system 19 transmits the timing signals Vsync, Hsync, DE, and MCLK together with the digital video data to the timing controller 16 .

The display panel DIS may have various planar shapes. That is, the display panel DIS may have a rectangular shape or a square shape, as well as various free form planar shapes such as a circular shape, an oval shape, and a polygonal shape.

The display panel DIS includes red (R), blue (B), and green (G) pixels Pix that emit red (R), blue (B), and green (G) light, respectively. If necessary, the display panel DIS may further include a pixel Pix emitting light of another color such as white W. Hereinafter, for convenience of description, a case in which the display panel DIS includes red (R), blue (B), and green (G) pixels Pix will be described as an example.

The pixel Pix may have various shapes. That is, the pixel Pix may have various planar shapes such as circular, oval, and polygonal shapes. Any one of the pixels Pix may have a different size and/or a planar shape than the other one. Each of the pixels Pix includes an organic light emitting diode.

The organic light emitting display device according to the present invention provides an organic compound layer emitting white (W) light to realize red (R), green (G) and blue (B), and red (R), blue (B) and It includes a color filter of green (G). That is, in the organic light emitting display device, white (W) light emitted from the organic compound layer is provided in regions corresponding to red (R), green (G), and blue (B) pixels Pix, respectively; By passing the green (G) and blue (B) color filters, red (R), green (G), and blue (B) may be realized.

In the case of the organic light emitting display device according to the present invention, since it is sufficient to form the organic compound layer emitting white (W) widely to cover most of the entire surface of the panel, red (R), blue (B) and green ( There is no need to use the FMM mask to distinguish each organic compound layer of G) and allocate it to the corresponding pixels Pix. Accordingly, the present invention has an advantage in that it is possible to prevent problems caused by using the above-described FMM, for example, a decrease in process yield when realizing high resolution, and poor alignment in which the organic compound layer is not formed in place.

Referring further to FIG. 2 , a plurality of data lines D and a plurality of gate lines G cross each other in the display panel DIS, and pixels Pix are arranged in a matrix form in each crossed area. Each pixel Pix is an organic light emitting diode (OLED), a driving thin film transistor (DT) that controls the amount of current flowing through the organic light emitting diode (OLED), and gate-source voltage of the driving thin film transistor (DT). It includes a programming unit (SC) for setting.

The programming unit SC may include at least one switched thin film transistor and at least one storage capacitor. The switched thin film transistor is turned on in response to a gate signal from the gate line G, thereby applying a data voltage from the data line D to one electrode of the storage capacitor. The driving thin film transistor DT controls the amount of light emitted from the organic light emitting diode OLED by controlling the amount of current supplied to the organic light emitting diode OLED according to the level of the voltage charged in the storage capacitor. The amount of light emitted from the organic light emitting diode OLED is proportional to the amount of current supplied from the driving thin film transistor DT. The pixel Pix is connected to the high potential voltage source Evdd and the low potential voltage source Evss, and receives a high potential power voltage and a low potential power voltage from a power generator (not shown), respectively. The thin film transistors constituting the pixel Pix may be implemented as a p-type or an n-type. In addition, the semiconductor layer of the thin film transistors constituting the pixel Pix may include amorphous silicon, polysilicon, or oxide. Hereinafter, a case in which the semiconductor layer includes an oxide will be described as an example. The organic light emitting diode (OLED) includes an anode (ANO), a cathode (CAT), and an organic compound layer interposed between the anode (ANO) and the cathode (CAT). The anode ANO is connected to the driving thin film transistor DT.

As shown in FIG. 3A , the sub-pixel includes the aforementioned switching transistor SW, driving transistor DR, capacitor Cst and organic light emitting diode OLED as well as internal compensation circuit CC. can do. The internal compensation circuit CC may include one or more transistors connected to the compensation signal line INIT. The internal compensation circuit CC sets the gate-source voltage of the driving transistor DR to a voltage in which the threshold voltage is reflected, so that when the organic light emitting diode OLED emits light, the luminance change due to the threshold voltage of the driving transistor DR is corrected. exclude In this case, the scan line GL1 includes at least two scan lines GL1a and GL1b to control the switching transistor SW and the transistors of the internal compensation circuit CC.

As shown in FIG. 3B , the sub-pixel may include a switching transistor SW1 , a driving transistor DR, a sensing transistor SW2 , a capacitor Cst, and an organic light emitting diode OLED. The sensing transistor SW2 is a transistor that may be included in the internal compensation circuit CC, and performs a sensing operation for compensation driving of the sub-pixel.

The switching transistor SW1 serves to supply the data voltage supplied through the data line DL1 to the first node N1 in response to the scan signal supplied through the first scan line GL1a. In addition, the sensing transistor SW2 initializes or senses the second node N2 positioned between the driving transistor DR and the organic light emitting diode OLED in response to the sensing signal supplied through the second scan line GL1b. plays a role

The structure of the pixel of the present invention is not limited thereto, and may be variously configured as 2T (Transistor) 1C (Capacitor), 3T1C, 4T2C, 5T2C, 6T2C, 7T2C, or the like.

4 is a plan view schematically illustrating two neighboring pixels of an organic light emitting diode display according to a preferred embodiment of the present invention. FIG. 5 is a cross-sectional view taken along line II′ of FIG. 4 . 6 is a cross-sectional view taken along II-II′ of FIG. 4 . 7 and 8 are diagrams for explaining the problems of the related art and the contrast effect of the present invention.

4 to 6 , an organic light emitting diode display according to a preferred embodiment of the present invention includes a thin film transistor substrate SUB. A thin film transistor T allocated to each of the pixels and an organic light emitting diode OLE connected to the thin film transistor T are disposed on the thin film transistor substrate SUB. Neighboring pixels may be partitioned by a bank BN (or a pixel defining layer), and a planar shape of each pixel may be defined by a bank BN. Accordingly, in order to form pixels having a preset planar shape, the position and shape of the bank BN can be appropriately selected.

The thin film transistor T may be implemented in various structures such as a bottom gate, a top gate, and a double gate structure. That is, the thin film transistor T may include a semiconductor layer, a gate electrode, and a source/drain electrode, and the semiconductor layer, the gate electrode, and the source/drain electrode may be disposed on different layers with at least one insulating layer interposed therebetween. can

At least one insulating layer may be interposed between the thin film transistor T and the organic light emitting diode OLE. The insulating layer may include a planarization layer OC made of an organic material such as photo acryl, polyimide, benzocyclobutene resin, or acrylate. The planarization layer OC may planarize the surface of the substrate SUB on which the thin film transistor T and various signal lines are formed. Although not shown, the insulating film may further include a passivation film PAS made of a silicon oxide film (SiOx), a silicon nitride film (SiNx), or a multilayer thereof, and the passivation film PAS includes a planarization film OC and a thin film transistor T ) can be interposed between The thin film transistor T and the organic light emitting diode OLE may be electrically connected through a pixel contact hole PH passing through one or more insulating layers.

The organic light emitting diode OLE includes a first electrode E1 , a second electrode E2 facing each other, and an organic compound layer OL interposed between the first electrode E1 and the second electrode E2 . . The first electrode E1 may be an anode, and the second electrode E2 may be a cathode.

In the organic light emitting display device, holes and electrons respectively injected from the first electrode E1 and the second electrode E2 are combined in the organic compound layer OL to form excitons that are excitons, and the formed axitons The image is displayed by emitting light while falling from the excited state to the ground state. Light generated inside the organic compound layer OL is emitted in multiple directions. In order to increase the luminous efficiency of the organic light emitting diode (OLE), it is necessary to control the propagation direction of the emitted light in one predetermined direction (hereinafter referred to as the directing direction). In order to control the propagation direction of the emitted light, the transmissive electrode and the reflective electrode may be disposed to face each other with the organic compound layer OL interposed therebetween. That is, in the organic light emitting diode display according to the present invention, which is implemented as a top emission type, the first electrode E1 functions as a reflective electrode, and the second electrode E2 functions as a transmissive electrode.

Some of the generated light traveling in the directing direction passes through the second electrode E2 and is emitted to the outside of the display device. Some other light is converted to the directing direction through the first electrode E1 and then passes through the second electrode E2 and the color filter in turn and is emitted to the outside of the display device. In this way, when the first electrode E1 is provided as a reflective electrode, the propagation direction of lights that do not travel in the initial directing direction can be switched to the directing direction, so that light efficiency can be improved.

The first electrode E1 is divided to correspond to each pixel, and at least one is allocated to each pixel, and may function as a reflective electrode composed of multiple layers including the reflective layer RL. The first electrode E1 is connected to the thin film transistor T through the pixel contact hole PH.

The first electrode E1 includes a reflective layer RL and a transparent functional layer TL disposed on the reflective layer RL. The reflective layer RL is a layer for reflecting the light propagated from the organic compound layer OL, and includes aluminum (Al), copper (Cu), silver (Ag), nickel (Ni), molybdenum (Mo), and aluminum neodium. (AlNd) or an alloy thereof, preferably APC (silver/palladium/copper alloy). The transparent functional layer TL is a layer functioning as an actual electrode, and in order to easily provide holes, indium tin oxide (ITO), indium zinc oxide (IZO), indium tin zinc oxide (ITZO), zinc oxide (Zinc Oxide) ) and a transparent conductive oxide (TCO) having a high work function, such as tin oxide.

The first electrode E1 may further include an adhesion improving layer AL disposed under the reflective layer RL. The adhesion improving layer AL is a layer for improving adhesion properties between the planarization film OC and the reflective layer RL, and includes indium tin oxide (ITO), indium zinc oxide (IZO), and indium tin zinc oxide (ITZO). , a transparent conductive oxide (TCO) such as zinc oxide and tin oxide. Hereinafter, for convenience of description, a case in which the first electrode E1 includes an adhesion improving layer AL, a reflective layer RL, and a transparent functional layer TL that are sequentially stacked will be described as an example.

A barrier layer DIL is positioned between the adjacent first electrodes E1 . The barrier layer (DIL) includes an inorganic material such as a silicon oxide film (SiOx), a silicon nitride film (SiNx), and a silicon oxynitride film (SiON), and polyimide, a benzocyclobutene resin, and an acrylate resin. It may be formed of a single layer made of an organic material such as acrylate, or a multi-layer in which these are stacked.

A bank BN partitioning neighboring pixels is positioned on the substrate SUB on which the first electrode E1 is formed. The bank BN may be formed of an organic material such as polyimide, benzocyclobutene resin, or acrylate. The bank BN includes an opening for exposing most of the central portion of the first electrode E1 . A portion of the first electrode E1 exposed by the bank BN may be defined as the emission area EA. The bank BN exposes the central portion of the first electrode E1 and is disposed to cover the side end of the first electrode E1 .

An organic compound layer OL emitting white W is formed on the substrate SUB on which the bank BN is formed. The organic compound layer OL is extended and disposed on the thin film transistor substrate SUB to cover the pixels. The organic compound layer OL may have a multi-stack structure. Among them, the two-stack structure includes a charge generation layer (CGL) disposed between the first electrode E1 and the second electrode E2, and lower and upper portions of the charge generation layer with the charge generation layer interposed therebetween. It may include a first stack and a second stack respectively disposed on the. Each of the first stack and the second stack includes an emission layer, and a hole injection layer, a hole transport layer, an electron transport layer, and an electron injection layer. ) and may further include at least one of common layers. The light emitting layer of the first stack and the light emitting layer of the second stack may include light emitting materials of different colors.

As another example, the organic compound layer OL emitting white (W) may have a single stack structure. Each single stack includes an emission layer (EML), a hole injection layer (HIL), a hole transport layer (HTL), an electron transport layer (ETL) and an electron injection layer ( At least one of common layers such as an electron injection layer (EIL) may be further included.

A second electrode E2 is formed on the substrate SUB on which the organic compound layer OL is formed. The second electrode E2 is made of a transparent conductive material such as Indium Tin Oxide (ITO), Indium Zinc Oxide (IZO), or Zinc Oxide (ZnO), or magnesium (Mg), calcium (Ca), aluminum (Al), An opaque conductive material such as silver (Ag) may be thinly formed to function as a transmissive electrode. The second electrode E2 may be integrally extended and disposed on the thin film transistor substrate SUB to cover the pixels.

An encapsulation layer (ENC) is formed on the organic light emitting diode (OLE). The encapsulation layer ENC may prevent moisture and/or oxygen from flowing into the organic light emitting diode OLE. Alternatively, as will be described later, when the color filter is disposed on the encapsulation layer ENC, the encapsulation layer ENC is interposed between the color filter and the organic light emitting diode OLE to emit organic light in an environment provided during the color filter forming process. A problem in which the diode OLE is exposed and deteriorated can be prevented. Accordingly, there is an advantage in that it is possible to prevent a decrease in lifetime and a decrease in luminance of the organic light emitting diode (OLE). The encapsulation layer ENC may be provided in a form in which at least one inorganic layer IOF and at least one organic layer OF are stacked. In this case, the inorganic layer IOF and the organic layer OF may be alternately disposed.

The organic light emitting diode display according to the present invention includes a color filter (not shown) to realize red (R), green (G), and blue (B). The color filter may include red (R), blue (B), and green (G) color filters. The neighboring color filters may be partitioned by a black matrix, but is not limited thereto. In the organic light emitting display device according to the present invention, white (W) light emitted from the organic compound layer OL is provided in red (R) regions corresponding to red (R), green (G), and blue (B) pixels, respectively. ), green (G), and blue (B) may be passed through the color filters to realize red (R), green (G), and blue (B).

For example, the color filter may be disposed on the encapsulation layer ENC. As another example, the color filter may be formed on a substrate (not shown) facing the thin film transistor substrate SUB. The opposing substrate may be made of a transparent material so that light emitted from the organic light emitting diode OLE can pass therethrough.

Hereinafter, the relationship between the first electrode E1 of the present invention and other layers including the barrier layer DIL will be described in more detail.

The first electrode E1 may include an adhesion improving layer AL, a reflective layer RL, and a transparent functional layer TL. The adhesion improving layer AL, the reflective layer RL, and the transparent functional layer TL are sequentially stacked on the planarization film OC. A barrier layer DIL is disposed between the adjacent first electrodes E1 .

An adhesion improving layer AL is disposed on the thin film transistor substrate SUB on which the planarization layer OC is formed. The adhesion improvement layer AL may be connected to the thin film transistor T through the pixel contact hole PH passing through the planarization layer OC. As described above, the adhesion improving layer AL is a layer interposed to secure adhesion properties between the planarization layer OC and the reflective layer RL, and may be omitted if necessary.

A barrier layer DIL is disposed on the thin film transistor substrate SUB on which the adhesion improvement layer AL is formed. The barrier layer DIL is disposed to cover at least a portion of the adhesion improvement layer AL. When the adhesion improvement layer AL is omitted, the barrier layer DIL may be disposed at a predetermined position so as not to overlap the pixel contact hole PH and the emission area EA. The barrier layer DIL may be disposed on the adhesion improvement layer AL to define a position of the reflective layer RL constituting the first electrode E1 and to guide the reflective layer RL to a position. .

A reflective layer RL is disposed on the thin film transistor substrate SUB on which the barrier layer DIL is formed. The reflective layer RL is disposed on the adhesion improvement layer AL. The reflective layer RL may be disposed to be in contact with a side surface of the barrier layer DIL. The reflective layer RL is disposed overlapping the light emitting area EA to at least cover the light emitting area EA. That is, one end RL_E of the reflective layer RL (or the edge portion of the reflective layer RL) is the same as the light emitting area EA or is disposed to further protrude to the outside of the light emitting area EA.

A transparent functional layer TL is disposed on the thin film transistor substrate SUB on which the reflective layer RL is formed. The transparent functional layer TL covers the upper surface of the reflective layer RL, is provided to have a larger area than the reflective layer RL, and further extends to cover at least a portion of the barrier layer DIL. That is, the one end TL_E of the transparent functional layer TL (or the edge portion of the transparent functional layer TL) protrudes more outward with respect to the light emitting area EA than the one end RL_E of the reflective layer RL. placed so as to

Since the one end TL_E of the transparent functional layer TL further extends outwardly from the one end RL_E of the reflective layer RL, a step is provided between the transparent functional layer TL and the reflective layer RL. The step provided by the transparent functional layer TL and the reflective layer RL is compensated by the barrier layer DIL. As the transparent functional layer TL extends to cover at least a portion of the reflective layer RL and the barrier layer DIL, a relatively wide upper surface may be provided.

The reason why the transparent functional layer TL should have a sufficient area lies in the ease of alignment between the first electrode E1 and the bank BN.

Specifically, as shown in FIG. 7A , the bank BN needs to be disposed to cover at least a portion of the first electrode E1 . However, since the width of the bank BN is relatively reduced in a high resolution display device having a high pixel per inch (PPI), accurate alignment is not easy. Referring to FIG. 7B , when the alignment between the bank BN and the first electrode E1 is misaligned, the organic compound layer OL is formed at the edge portion of the first electrode E1 by the first electrode E1 . ) is thinly formed by the step difference. In this case, as the current is concentrated in the portion where the organic compound layer OL is thinly formed, a short may occur between the first electrode E1 and the second electrode E2 , which is a problem.

In order to prevent the above-described defects, in a preferred embodiment of the present invention, the area of the transparent functional layer TL that is disposed on the uppermost layer among the layers constituting the first electrode E1 and is in contact with the bank BN is sufficiently secured. do.

The reason why the reflective layer RL should have a smaller area than the transparent functional layer TL is to improve color mixing.

In detail, some of the light emitted from the organic compound layer OL may not pass through a color filter assigned to a corresponding pixel, but may travel toward an adjacent color filter. In this case, since color mixing defects occur, the display quality is remarkably deteriorated, which is a problem. In order to improve the color mixing defect, a black matrix may be provided. Furthermore, in order to effectively improve color mixing defects by using the black matrix, a cell gap may be adjusted or the width of the black matrix may be appropriately adjusted.

However, referring to (a) of FIG. 8 , some of the light emitted from the organic compound layer OL causes total reflection between the interfaces of the thin film layers due to the difference in refractive index between the thin film layers provided in the light propagation path to neighboring pixels. It may wave guide in a direction, or it may travel in the direction of neighboring pixels through the surface and interior of the bank BN. Lights directed to a neighboring pixel do not exit in a directing direction, are reflected by the reflective layer RL of the first electrode E1 , and then travel toward a neighboring color filter, thereby causing color mixing defects.

For example, if the width of the bank BN is relatively narrow in response to a high-resolution display device, the taper of the bank BN pattern may be set to 45° or more. In this case, most of the light (①, ②) that is totally reflected at the interface between the inorganic film (IOF) and the organic film (OF) constituting the encapsulation layer (ENC) and refracted and/or reflected by the taper of the bank (BN) is , is not lost in the encapsulation layer ENC and the bank BN, and is incident on the reflective layer RL of a neighboring pixel, acting as a major factor causing the above-described color mixing defect, which is a particular problem. Since the traveling direction of these lights (①, ②) may be severely shifted from the directing direction, there is a limit to blocking them using the black matrix BM.

Referring to (b) of FIG. 8 , in the present invention, the area of the reflective layer RL is formed to be relatively narrow in order to prevent the above-described defect. In this case, since it is possible to minimize a region in which the light causing the color mixing defect can be reflected, there is an advantage in that the color mixing defect can be minimized. That is, the first of the lights (①, ②) that are totally reflected at the interface between the inorganic film IOF and the organic film OF constituting the encapsulation layer ENC and are refracted and/or reflected by the taper of the bank BN. Since the amount of light incident on the reflective layer RL of the electrode E1 can be minimized, color mixing defects can be remarkably improved.

As described above, the transparent functional layer TL needs to have a maximum area within a preset range, and the reflective layer RL needs to have a minimum area within a preset range. Accordingly, the one end TL_E of the transparent functional layer TL has a shape that more protrudes outward with respect to the light emitting area EA than the one end RL_E of the reflective layer RL. In this case, in order to maintain the protruding shape of the one end TL_E of the transparent functional layer TL, it is necessary to compensate for the step provided by the transparent functional layer TL and the reflective layer RL. To this end, a barrier layer (DIL) is provided.

The barrier layer DIL is disposed in the bank BN. Accordingly, light entering the bank BN may be refracted and/or reflected at the interface between the bank BN and the barrier layer DIL to travel in an undesired direction, which may cause color mixing defects. To control this, the barrier layer DIL is preferably made of a material having substantially the same refractive index as that of the bank BN.

In addition, the barrier layer (DIL) may preferably have a lower refractive index than that of the transparent functional layer (TL). In this case, since some of the light passing through the transparent functional layer TL and directed to the reflective layer RL will be refracted at the interface between the high refractive index transparent functional layer TL and the low refractive index barrier layer DIL, the reflective layer (RL) may not be incident. Accordingly, since the amount of light incident on the reflective layer RL can be further reduced, color mixing defects can be improved.

9 is a flowchart showing a process for forming the first electrode of the present invention.

Referring to FIG. 9 together with FIGS. 5 and 6 , in the method for manufacturing an organic light emitting display device according to a preferred embodiment of the present invention, the first step of forming the adhesion improving layer AL ( S100 ), the barrier layer (DIL) ), a second step S200 of forming the reflective layer RL, a third step S300 of forming the reflective layer RL, and a fourth step of forming the transparent functional layer TL. In describing the manufacturing method according to the present invention, the steps are divided, but this is for convenience of description, and it should be noted that each step may be further subdivided and may be further added.

The first step ( S100 ) is a step of forming the adhesion improving layer AL by applying a first transparent conductive material on the planarization layer OC and patterning it.

The second step S200 is a step of forming the barrier layer DIL by applying an insulating material on the adhesion improvement layer AL and the planarization layer OC and patterning the insulating material. The barrier layer DIL is disposed to cover at least a portion of the patterned adhesion improving layer AL. One end of the barrier layer DIL is extended to a predetermined position on the adhesion improvement layer AL in consideration of the position of the reflective layer RL to be formed later.

The third step S300 is a step of forming a reflective layer RL by applying a reflective material on the barrier layer DIL and the planarization layer OC and patterning the reflective material. The reflective layer RL is disposed on the adhesion improving layer AL. One end RL_E of the reflective layer RL may be in contact with one end of the barrier layer DIL on the adhesion improvement layer AL. The position of the reflective layer RL may be guided by the barrier layer DIL, and is selected in consideration of the position of the transparent functional layer TL and the position of the bank BN to be formed later.

A fourth step is a step of forming a transparent functional layer TL by applying a second transparent conductive material on the reflective layer RL and the planarization layer OC and patterning the second transparent conductive material. The transparent functional layer TL is disposed on the barrier layer DIL and extends to cover at least a portion of the barrier layer DIL. The area of the transparent functional layer TL is selected in consideration of the alignment tolerance with the bank BN.

At least a portion of the transparent functional layer TL exposed to the opening of the bank BN is defined as the light emitting area EA. The position of one end RL_E of the reflective layer RL is related to the position of one end BN_E of the bank BN defining the light emitting area EA and the position of one end TL_E of the transparent functional layer TL.

A position of one end RL_E of the reflective layer RL may be selected to correspond to an overlapping region in which the bank BN and the transparent functional layer TL overlap. Specifically, the position of one end RL_E of the reflective layer RL is selected to be substantially the same as that of one end BN_E of the bank BN, or the one end BN_E of the bank BN and the transparent functional layer TL It may be selected as any one position between the ends RG of the TL_E. In consideration of the above problems, it is preferable that the position RL_E of one end of the reflective layer RL corresponds to the first position or is disposed as close to the first position as possible.

10 is a diagram for explaining a comparison between the manufacturing method of the first electrode E1 and the general manufacturing method according to the preferred embodiment of the present invention.

The first electrode E1 includes a transparent functional layer TL, a reflective layer RL, and an adhesion improvement layer AL.

Referring to FIG. 10A , to form the first electrode E1 , the second transparent conductive material ALM, the reflective material RLM, and the first transparent conductive material TLM are formed on the planarization layer OC. ) are sequentially applied. In consideration of the thickness of each layer, two etching processes for patterning the second transparent conductive material ALM, the reflective material RLM, and the first transparent conductive material TLM are sequentially performed. That is, by sequentially performing a first etching process for patterning the first transparent conductive material TLM and a second etching process for simultaneously patterning the reflective material RLM and the second transparent conductive material ALM, each pixel The first electrodes E1 including the transparent functional layer TL, the reflective layer RL, and the adhesion improving layer AL may be formed thereon.

However, referring to FIG. 10B , during the first etching process, the first transparent conductive material TLM cannot be completely removed from the preset region due to crystallization of the first transparent conductive material TLM, and the reflective layer RL is formed. A residual film may remain on it. In this case, even in the subsequent etching process, the second transparent conductive material ALM, the reflective material RLM, and the first transparent conductive material TLM are not completely separated and remain connected in at least one region, so that adjacent pixels are separated from each other. A short will occur.

Therefore, in order to prevent a short circuit defect, the transparent functional layer TL, the reflective layer RL, and the adhesion improving layer AL constituting the first electrode E1 need to be patterned, respectively. In consideration of this, the preferred embodiment of the present invention has the advantage of remarkably improving color mixing defects without excessively increasing the process steps compared to the related art.

This defect is more severe in a structure in which a micro-cavity is applied between the first electrode E1 and the second electrode E2 as an optical cavity in order to improve light efficiency and color gamut. can be problematic. In particular, the above-described defect may be more problematic in a microcavity structure in which constructive interference is generated according to a target wavelength by adjusting (optimizing) the thickness of the transparent functional layer TL constituting the first electrode E1. have. For example, in order to form different thicknesses of the transparent functional layer (TL) of the R, G, and B pixels, deposition and etching processes need to be performed three or more times. In this case, the reflective layer (RL) ) is exposed and can be damaged.

In the present invention, since the barrier layer DIL is formed before the transparent functional layer TL is formed, the reflective layer RL is not directly exposed to the environment provided during the transparent functional layer TL forming process. Accordingly, it is possible to prevent the reflective layer RL from being directly exposed and damaged during the process of forming the transparent conductive layer TL.

Those skilled in the art through the above description will be able to make various changes and modifications without departing from the technical spirit of the present invention. Accordingly, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification, but should be defined by the claims.

SUB : thin film transistor substrate T : thin film transistor
OLE: organic light emitting diode E1: first electrode
AL: adhesion improving layer RL: reflective layer
TL: Transparent functional layer OL: Organic compound layer
E2: second electrode BN: pixel defining layer
ENC: encapsulation layer

Claims (16)

An organic light emitting diode display comprising a transistor and an organic light emitting diode connected to the transistor, the organic light emitting diode display comprising:
The first electrode of the organic light emitting diode,
reflective layer; and
a transparent functional layer disposed on the reflective layer, one end of which protrudes more outward than one end of the reflective layer;
a bank having an opening exposing at least a portion of the first electrode; and
Compensating for the step provided by the reflective layer and the transparent functional layer, comprising a barrier layer in contact with the side surface of the reflective layer,
One end of the reflective layer is positioned to correspond to an area where the bank and the transparent functional layer overlap,
The transparent functional layer covers at least a part of the barrier layer, the organic light emitting display device.
The method of claim 1,
The area of the transparent functional layer is,
An organic light emitting display device having a larger area than the reflective layer.
delete The method of claim 1,
One end of the reflective layer,
An organic light emitting diode display positioned at the same position as one end of the bank.
The method of claim 1,
The position of one end of the reflective layer is,
an organic light emitting display device selected between one end of the bank and one end of the transparent functional layer.
delete delete delete The method of claim 1,
The barrier layer is
A single layer made of any one selected from silicon oxide (SiOx), silicon nitride (SiNx), silicon oxynitride (SiON), polyimide, benzocyclobutene resin, and acrylate An organic light emitting display device comprising multiple layers in which they are stacked.
The method of claim 1,
Further comprising a bank covering at least a portion of the first electrode,
The barrier layer is
an organic light emitting diode display having the same refractive index as that of the bank.
The method of claim 1,
The first electrode is
Further comprising an adhesion improving layer disposed under the reflective layer,
The barrier layer is
and covering at least a portion of the adhesion improving layer.
12. The method of claim 11,
The adhesion improving layer,
made of a transparent conductive oxide (TCO) including indium tin oxide (ITO), indium zinc oxide (IZO), indium tin zinc oxide (ITZO), zinc oxide (Zinc Oxide) and tin oxide (Tin Oxide) , an organic light emitting display device.
The method of claim 1,
The transparent functional layer,
made of a transparent conductive oxide (TCO) including indium tin oxide (ITO), indium zinc oxide (IZO), indium tin zinc oxide (ITZO), zinc oxide (Zinc Oxide) and tin oxide (Tin Oxide) , an organic light emitting display device.
The method of claim 1,
The reflective layer is
An organic light emitting display device comprising aluminum (Al), copper (Cu), silver (Ag), nickel (Ni), molybdenum (Mo), aluminum neodium (AlNd), or an alloy thereof.
The method of claim 1,
Further comprising an encapsulation layer covering the organic light emitting diode,
The encapsulation layer is
An organic light emitting display device having a structure in which an organic material and an inorganic material are stacked. Board;
a thin film transistor disposed on the substrate;
a planarization film covering the thin film transistor;
a first electrode connected to the thin film transistor on the planarization layer and having a reflective layer and a transparent functional layer disposed on the reflective layer;
a barrier layer disposed on a side surface of the first electrode;
a bank defining an opening exposing a central portion of the first electrode on the first electrode;
an organic compound layer disposed on the first electrode and the bank; and
A second electrode disposed on the organic compound layer,
The barrier layer is
It is in contact with the side surface of the reflective layer and has an upper surface at the same height as the upper surface of the reflective layer,
The transparent functional layer,
It covers the upper surface of the reflective layer and extends to cover a part of the barrier layer,
The bank is
An organic light emitting display device covering the barrier layer and exposing a portion of the transparent functional layer to define a light emitting area.

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