KR100647599B1 - Organic electro-luminescent display device and fabricating the same - Google Patents

Abstract

An object of the present invention is to reduce the voltage drop of an upper electrode of an organic light emitting display device to improve luminance unevenness of pixels. In order to achieve the above object, an insulating substrate having an insulating layer; A first electrode formed on the insulating layer, and an auxiliary electrode formed on the same layer as the first electrode; A groove formed in the insulating layer having a predetermined depth along an edge of at least one side of the auxiliary electrode; A pixel defining layer defining the first electrode; An organic layer formed on at least the first electrode layer and including a light emitting layer; And a second electrode covering the organic layer and electrically connected to the auxiliary electrode.

Description

Organic electroluminescent display device and manufacturing method therefor {Organic electro-luminescent display device and fabricating the same}

1 is a plan view illustrating a pixel portion of a conventional organic light emitting display device.

FIG. 2 is a cross-sectional view of a pixel portion of the organic light emitting display device of FIG. 1.

3 is a plan view of an organic light emitting display device according to an exemplary embodiment of the present invention.

4 illustrates a cross-sectional view of one pixel in the plan view of FIG. 3.

5 is a cross-sectional view of an organic light emitting display device according to another exemplary embodiment of the present invention.

FIG. 6 is a cross-sectional view illustrating in more detail around the auxiliary electrode in FIG. 5.

7 is a cross-sectional view of the auxiliary electrode in FIG. 5 in more detail.

8 is a plan view of an organic light emitting display device according to a preferred embodiment of the present invention.

9 is a plan view of an organic light emitting display device according to a preferred embodiment of the present invention.

10 is a plan view of an organic light emitting display device according to a preferred embodiment of the present invention.

<Explanation of symbols for main parts of the drawings>

Vdd; Power line scan; Scanning line

Data; Data Line Cst: Rechargeable Capacitor

100,200; Insulating substrates 110,210; Buffer layer

120,220; Active layer 130,2300; Gate insulating film

141,241; Gate electrodes 150, 250; Interlayer insulation film

161,261; Source and drain electrodes 170,270; Passivation film

175,275; Planarization films 170a, 175a, 270a, and 275a; Via Hole

180,280; First electrodes 190,290,291,292; Organic layer

195,295; Second electrode 265; Wiring part and electric element

280a; Auxiliary electrode 280b; Groove

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic light emitting display and a method of manufacturing the same. More particularly, an organic light emitting display capable of preventing luminance unevenness and increasing size by reducing a voltage drop by using an auxiliary electrode that reduces a voltage drop of an upper electrode. And a method for producing the same.

In general, an organic light emitting display device is a self-luminous display that electrically excites fluorescent organic compounds to emit light, and can be driven at low voltage, is easy to thin, and is pointed out as a problem in liquid crystal display devices such as wide viewing angle and fast response speed. It is attracting attention as the next generation display that can solve the shortcomings. In the organic light emitting display, an organic layer having a predetermined pattern is formed on glass or other transparent insulating substrate, and electrode layers are formed on upper and lower portions of the organic layer. The organic layer consists of an organic compound. In the organic light emitting display device configured as described above, as the anode and cathode voltages are applied to the electrodes, holes injected from the electrode to which the anode voltage is applied are moved to the light emitting layer via the hole transport layer, and the electrons have a cathode voltage. It is injected from the applied electrode into the light emitting layer via the electron transport layer. In this light emitting layer, electrons and holes recombine to produce excitons, and as the excitons change from the excited state to the ground state, the fluorescent molecules in the light emitting layer emit light to form an image.

Among such organic light emitting display devices, an active matrix active matrix (AM) type organic light emitting display device includes at least two thin film transistors (hereinafter, referred to as TFTs) for each pixel. These thin film transistors are used as switching elements for controlling the operation of each pixel and as driving elements for driving the pixels. Such a thin film transistor has a semiconductor active layer having a drain region and a source region doped with a high concentration of impurities on a substrate, and a channel region formed between the drain region and the source region, the gate insulating film formed on the semiconductor active layer, and the active layer And a gate electrode formed on the gate insulating film above the channel region of the channel region, a drain electrode and a source electrode connected through the contact hole with the drain region, the source region, and the like between the interlayer insulating film on the gate electrode.

1 is a plan view illustrating a pixel portion of an active matrix organic electroluminescent display, and FIG. 2 is a cross-sectional view of a pixel portion of an organic electroluminescent display.

First, as shown in FIG. 1, the organic light emitting display device has a plurality of subpixels. A single subpixel is surrounded by a scan line (Scan), a data line (Data), and a power supply line (Vdd). Each subpixel is most simply a switching TFT (TFTsw) for switching and a driving TFT (TFTdr) for driving. At least two thin film transistors, and one capacitor Cst and one organic light emitting diode OLED. The number of thin film transistors and capacitors as described above is not necessarily limited thereto, and of course, a larger number of thin film transistors and capacitors may be provided.

The switching TFT TFTsw is driven by a scanning signal applied to the scan line Scan to transfer a data signal applied to the data line Data. The driving TFT TFTdr is transferred to the organic light emitting diode OLED through the driving line Vdd according to the data signal transmitted through the switching TFT TFTsw, that is, the voltage difference Vgs between the gate and the source. Determine the amount of current flowing in. The capacitor Cst stores a data signal transmitted through the switching TFT TFTsw for one frame.

FIG. 2 illustrates a cross-sectional view of the active matrix organic electroluminescent display. As shown in FIG. 2, a buffer layer 110 is formed on a first substrate 100 made of glass, and a thin film is formed thereon. The transistor TFT and the organic electroluminescent element OLED are formed.

Such an active matrix organic light emitting display device is generally formed as follows.

First, the semiconductor active layer 121 of a predetermined pattern is provided on the buffer layer 110 of the substrate 100. The gate insulating layer 130 is formed on the semiconductor active layer 121 by SiO _2, and the gate electrode 141 is formed on the predetermined region on the gate insulating layer 130 by a conductive film such as MoW or Al / Cu. The gate electrode 141 is connected to a gate line (not shown) for applying a TFT on / off signal. An inter-insulator 150 is formed on the gate electrode 141, and the source / drain electrodes 161 contact the source region and the drain region of the semiconductor active layer 121 through contact holes. Is formed. In forming the source / drain electrodes 161, a power supply line Vdd is also formed. A passivation film 170 made of SiO ₂ , SiNx, or the like is formed on the source / drain electrode 23, and a planarization film (eg, acrylic, polyimide, BCB, or the like) is formed on the passivation film 170. 175 is formed.

The passivation film 170 and the planarization film 175 are formed with via holes 170a and 175a which are connected to the source / drain electrodes 161 by photolithography or perforation. The lower electrode layer 180 serving as the anode electrode is formed on the planarization film 175 so that the lower electrode layer 180 is electrically connected to the source / drain electrode 161. A pixel define layer 185 is formed of an organic material to cover the lower electrode layer 180. After the predetermined opening is formed in the pixel defining layer 185, the organic layer 190 is formed in the region defined by the opening. The organic layer 190 includes a light emitting layer. The upper electrode layer 195, which is a cathode electrode, is formed to cover the organic layer 190. The organic layer 190 emits light when holes and electrons are injected from portions of the lower electrode layer 180 and the upper electrode layer 195 that face each other.

Meanwhile, in the top emission type organic light emitting display device, a transparent cathode electrode is used to emit light toward the encapsulation substrate. Generally, a transparent conductive material such as ITO or IZO is mainly used for the transparent cathode electrode, but a metal material having a low work function (eg, MgAg) on the side contacting the organic layer in order to function as a cathode electrode is used. A thin film is formed to form a metal film, and a thick film of ITO or IZO is used on the metal film. In particular, such a structure is essential in a top-emitting display device that emits light from the substrate toward the electrode.

However, in the above process, since the ITO or IZO is formed after the organic layer is formed, it is formed by low temperature deposition in order to minimize the damage of the organic layer by heat or plasma (plasma), the film quality is bad, the specific resistance is high. In addition, due to the high resistivity of the cathode, the same cathode voltage is not applied to each pixel position, but a voltage difference occurs in a region near and far from a region where power is input due to voltage drop (IR drop). As a result, unevenness in luminance and image characteristics occurs, and power consumption rises. Due to the voltage drop, it is difficult to manufacture a large organic light emitting display device. A problem that is difficult to manufacture a large display device exists in a back light emitting display device as well as a top light emitting display device.

As a method for solving the above problem, a method of forming an auxiliary electrode for preventing an upper electrode voltage drop on the pixel defining layer 185 is known, as shown in FIG. 2. In this method, the auxiliary electrode 193 is formed on the pixel defining layer 185 to prevent the lowering of the upper electrode voltage, and the upper electrode 195 is formed on the entire surface of the insulating substrate 100. Have In FIG. 1, the auxiliary electrode 193 is distributed in the hatched line indicated by the pixel definition layer 185.

However, in the method of forming the auxiliary electrode 193, the organic layer 190 may be damaged when the metal film used as the auxiliary electrode line 193 is deposited and patterned on the pixel defining layer 185. In addition, a mask process is added to form the auxiliary electrode 193 for preventing the upper electrode voltage drop, and thus, the process is complicated. In particular, in order to simplify the manufacturing process, regardless of the R, G, B color system or monochromatic system, the hole injection layer (HIL), the hole transport layer (HTL), the electron transport layer (ETL), excluding the light emitting layer, among the organic layers 190, Organic common layers such as an electron injection layer (EIL) are applied over the entire area of the pixel definition layer. In this case, a contact hole for electrically connecting the cathode electrode 195 and the auxiliary electrode 193 must be formed separately. This becomes very complicated.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and an object of the present invention is to prevent a voltage drop of a cathode electrode through an auxiliary electrode, thereby improving brightness and image characteristics, and increasing the size of an organic light emitting display device. It is providing the manufacturing method.

Another object of the present invention is to provide an organic electroluminescent display device and a method of manufacturing the auxiliary electrode which are formed simultaneously with the anode electrode, and which do not require an additional process for electrical connection with the cathode electrode through over etching at the time of formation. It's there.

Further, another object of the present invention is to provide a highly reliable organic electroluminescent display device having no defect in electrical connection between the auxiliary electrode and the cathode electrode and a manufacturing method thereof.

The present invention for achieving the above object, the insulating substrate having an insulating layer;

A first electrode formed on the insulating layer, and an auxiliary electrode formed on the same layer as the first electrode;

A groove formed in the insulating layer having a predetermined depth along an edge of at least one side of the auxiliary electrode;

A pixel defining layer defining the first electrode;

An organic layer formed on at least the first electrode layer and including a light emitting layer; And

And a second electrode covering the organic layer and electrically connected to the auxiliary electrode.

As a result, the organic layer is disposed in the groove positioned at the edge of the first electrode and does not cover the side surface of the auxiliary electrode, so that an organic light emitting display device having a smooth electrical connection between the first electrode and the auxiliary electrode can be provided.

According to another feature of the present invention, the pixel defining layer may be provided to expose a portion of the first electrode, the auxiliary electrode and the groove.

According to another feature of the invention, the organic layer may include an organic common layer other than the light emitting layer, the organic common layer may be provided to cover the auxiliary electrode and the groove.

According to another feature of the invention, the second electrode may be electrically connected to the auxiliary electrode through the side surface of the auxiliary electrode.

According to another feature of the invention, the depth of the groove may be larger than the thickness of the auxiliary electrode, it may be smaller than the thickness of the insulating layer.

According to another feature of the invention, between the insulating layer and the insulating substrate is provided with an electric element including a wiring portion, the depth of the groove may be a depth such that the bottom of the groove does not touch the electric element. .

According to another feature of the invention, the electrical element may be a thin film transistor electrically connected to the first electrode.

According to another feature of the invention, the auxiliary electrode may be of a linear structure (grid) or a grid (grid) structure.

On the other hand, to achieve the above object, a method of manufacturing an organic light emitting display device according to another embodiment of the present invention, comprising: applying an electrode material on an insulating substrate having an insulating layer;

Patterning the electrode material to form an auxiliary electrode and a first electrode, wherein the groove is overetched along an edge of at least one side of the auxiliary electrode to form a groove in the insulating layer;

Forming a pixel defining layer to partition the first electrode;

Forming an organic layer including a light emitting layer on at least the first electrode layer; And

Forming a second electrode covering the organic layer and electrically connected to the auxiliary electrode through at least a side surface of the auxiliary electrode; and providing a method of manufacturing an organic light emitting display device.

According to another feature of the invention, the over-etching may be made so that the depth of the groove is greater than the thickness of the auxiliary electrode, the depth of the groove may be made smaller than the thickness of the insulating layer.

According to another feature of the invention, the over-etching may be made so that the depth of the groove, the lower end of the groove does not touch the electrical element including the wiring portion between the insulating layer and the insulating substrate.

Hereinafter, with reference to the accompanying drawings, it will be described a preferred embodiment of the present invention.

3 is a plan view of an organic light emitting display device according to an exemplary embodiment of the present invention, and shows some pixels in a pixel portion, and FIG. 4 is a cross-sectional view of one pixel in the plan view of FIG. 3.

3 is an auxiliary electrode 280a electrically connected to an upper electrode on a data line Data or a power line Vdd, as compared with the plan view of the conventional organic electroluminescent display of FIG. 1. The point is different. Although not shown in FIG. 3, the auxiliary electrode 280a may be disposed on the scan line Scan and may be disposed in all regions except for the organic light emitting diode OLED.

Although the scope of the present invention is not limited thereto, in the case of the top emission type organic light emitting display device that emits light from the substrate toward the display electrode, the area of the organic light emitting diode (OLED) may be set to maximize the opening. It can be enlarged to almost any area except the perimeter of each pixel. In this case, the auxiliary electrode 280a may be formed around the periphery of each pixel in which the organic light emitting diode OLED is not disposed. Therefore, the auxiliary electrode 280a is referred to as an electric element including a wiring part (hereinafter referred to as an electric element). ) May be disposed in the vicinity of the distributed position.

In the present specification, the electric element refers to all wiring portions between the insulating layer and the substrate and an electrically operated element. For example, the data line Datat, the power supply line Vdd, the scan line San, The source and drain 261, the gate electrode 241, the semiconductor layer 221, and the capacitor Cst of the thin film transistor are referred to.

Referring to the cross-sectional view of FIG. 4, an organic light emitting display device according to an embodiment of the present invention includes a semiconductor layer 221 formed on an insulating substrate 200 and a buffer layer 210, and a gate insulating layer 230 thereon. And a source electrode and a drain electrode 261 connected to the active semiconductor layer 221 through a contact hole in the interlayer insulating film 250 thereon.

Wiring parts such as the power line Vdd, the data line, the scan line, and the like of the electric element 265 are generally disposed around the boundary line between the pixels, but are not necessarily limited thereto. .

Insulating layers 270 and 275 are disposed on the source and drain electrodes 261 and the electric element 265 to protect and insulate them. In general, the insulating layer preferably comprises a passivation film 270 made of SiO ₂ , SiNx, or the like, and a planarization film 275 made of organic materials such as acrylic, polyimide, BCB, etc. It can also be done.

A first electrode 280 and an auxiliary electrode 280a may be disposed on the insulating substrate on which the insulating layers 270 and 275 are formed, which may serve as an anode of the organic light emitting diode OLED. The auxiliary electrode 280a is electrically insulated from the first electrode 280. The first electrode 280 is electrically connected to the source or drain electrode 261 of the thin film transistor through the via holes 270a and 275a.

As shown in FIG. 4, a groove 280b is formed in the side portion (both end side or one side side) of the auxiliary electrode 280a which is dug by a predetermined depth toward the inside of the insulating layer. The first opening 285a is formed so that the pixel defining layer 285 covers the edge portion of the first electrode, and the second opening portion 285 is not formed so that the pixel defining layer 285 does not cover the side surface of the auxiliary electrode 280a. 285b).

In consideration of the simplification of the manufacturing process, in the case of a monochromatic organic electroluminescent display, organic layers 290, 291 and 292 are formed over the entire surface of the insulating substrate. The organic layer is formed of a first organic common layer 290 made of a hole injection layer (HIL), a hole transport layer (HTL), etc., a light emitting layer 291, an electron transport layer (ETL), an electron injection layer (EIL), or the like. Two organic common layers 292. Even when the organic layers 290, 291 and 292 are applied over the entire surface of the insulating substrate, the side surfaces of the auxiliary electrodes 280a are not shielded by the organic layers 290, 291 and 292 due to the grooves 280b formed at both ends of the auxiliary electrodes 280a. Thus, the auxiliary electrode 280a may be electrically connected at its side with the second electrode 295 which is subsequently applied over the entire surface of the substrate.

5 is a cross-sectional view of an organic light emitting display device according to another exemplary embodiment of the present invention. 5, the light emitting layer 291 of the organic layer is distributed only in the first opening 285a defined by the pixel defining layer 285, and the portion except the first opening 285a is The difference is that only the organic common layers 290 and 292 except the light emitting layer 291 are distributed. In order to simplify the manufacturing process, in the R, G, and B full color schemes, the light emitting layer 291 distributed in each subpixel is distributed only in the first opening 285a and is organically common to the portions except the first opening 285a. Layers 290 and 292 are distributed. In this case, the organic common layers 290 and 292 are coated on the upper surface of the auxiliary electrode 280a and the grooves 280b at both ends of the auxiliary electrode, but both side surfaces of the auxiliary electrode 280a are sealed to the organic common layers 290 and 292. Since both sides of the second electrode 295 and the auxiliary electrode 280a are not electrically connected to each other.

Without considering the simplification of the manufacturing process, the organic common layers 290 and 292 may also be distributed only in the first opening 285a and not in other regions. In this case, the auxiliary electrode 280a is electrically connected to the second electrode 295 which is a cathode electrode at both end sides and the upper surface thereof.

On the other hand, in order to avoid the complicated manufacturing process, it is preferable that the first electrode 280 and the auxiliary electrode 280a serving as the anode electrode are formed in the same layer with the same material.

In order to emit light in a direction opposite to the substrate, the first electrode 280 is formed of a reflective film made of Ag, Mg, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, or a compound thereof. Thereafter, ITO, IZO, ZnO, or In ₂ O ₃ may be formed thereon. More preferably, the first electrode 280 and the auxiliary electrode 280a have a low specific resistance in order to minimize the voltage drop of the second electrode, and Al having excellent reflectance to increase the reflectance of the organic layer formed in a subsequent process. It is preferably made of a material that can be used as -ITO, Mo-ITO, Ti-ITO or Ag-ITO or other reflective film or anode electrode.

When emitting light in the direction of the substrate, the first electrode 280 may be formed of a transparent electrode made of ITO, IZO, ZnO, In ₂ O ₃ , or the like.

On the other hand, the organic layers 290, 291, 292 formed on the opening may be a low molecular or polymer organic layer, when using a low molecular organic layer, a hole injection layer (HIL), a hole transport layer (HTL), an organic light emitting layer (EML: Emission Layer), Electron Transport Layer (ETL), Electron Injection Layer (EIL), etc. may be formed by stacking in a single or complex structure, and the usable organic material may also be formed of copper phthalocyanine ( CuPc: copper phthalocyanine), N, N-di (naphthalen-1-yl) -N, N'-diphenyl-benzidine (N, N'-Di (naphthalene-1-yl) -N, N'-diphenyl- benzidine: NPB), tris-8-hydroxyquinoline aluminum (Alq3) and the like can be variously applied. These low molecular weight organic layers are formed by the vacuum deposition method.

In the case of the polymer organic layer, the structure may include a hole transporting layer (HTL) and a light emitting layer (EML). In this case, PEDOT is used as the hole transporting layer, and polyvinylvinylene (PPV) and polyfluorene are used as the light emitting layer. Polymer organic materials such as (Polyfluorene) are used and can be formed by screen printing or inkjet printing.

The organic layer as described above is not necessarily limited thereto, and various embodiments may be applied.

On the other hand, the second electrode layer 295 formed on the organic layers 290, 291, 292 may also be provided as a transparent electrode or a reflective electrode, when used as a transparent electrode (for example, to emit light in a direction opposite to the substrate) The second electrode layer 295 is formed of a metal having a small work function, that is, a thin metal layer having a thickness of about 100 μs consisting of Li, Ca, LiF / Ca, LiF / Al, Al, Mg, MgAg, and a compound thereof. After the deposition is directed in the direction of, a material for forming a transparent electrode such as ITO, IZO, ZnO, or In ₂ O ₃ may be formed thereon.

And, when the second electrode 295 is used as a reflective electrode (for example, to emit light toward the substrate), Li, Ca, LiF / Ca, LiF / Al, Al, Mg, MgAg, and their The compound is formed by full deposition.

As described above, since the organic layer 290 is not formed on the side surface of the auxiliary electrode 280a, the second electrode 295 is electrically connected to the side surface of the auxiliary electrode 280a and thus, the second electrode 295. By lowering the resistance of the voltage drop (IR drop) can be reduced.

6 and 7 are cross-sectional views illustrating in more detail around the auxiliary electrode in FIG. 5.

Referring to FIG. 6, the auxiliary electrode 280a has a predetermined thickness t1, and a groove 280b having a predetermined depth t2 is formed on at least one side of both ends of the auxiliary electrode 280a. . The depth t2 of the groove 280b should be sufficiently deep so that the organic layers 290, 292 or 291 stacked on the groove 280b do not cover the side of the auxiliary electrode 280a. Therefore, the depth t2 of the groove 280b is preferably at least larger than the thickness t1 of the auxiliary electrode 280a. The deeper the depth t2 of the groove 280b, the higher the possibility that the side surface of the auxiliary electrode 280a is not covered by the organic layers 290, 292 or 291. However, the groove 280b should not short-circuit the second electrode layer 295 with an electrical element 265 such as a wiring portion, a source or drain electrode 261 of the thin film transistor TFT, and a charging capacitor Cst. . Since the electrical elements 265 such as data lines, power lines and scan lines, thin film transistors, and charging capacitors are interposed between the insulating layers 270 and 275 and the substrate 200, the depth t2 of the groove 280b is at least. It is desirable to be smaller than the thickness t3 or t4 or t3 + t4 of the insulating layers 275 and 270.

Referring to FIG. 7, the depth t2 of the groove 280b is the same as that of FIG. 6 except that it is greater than that in FIG. 6.

In this manner, especially when the depth t2 of the groove 280b is large, the electrical elements 265 such as the data line Data, the power supply line Vdd, and the scan line Scan do not overlap with the groove 280b. Should be considered. Therefore, when the electric element 265 is disposed below the groove 280b, the depth t2 of the groove 280b is at least the insulating layers 275 and 270 so that the lower end of the groove does not touch the electric element 265. Is smaller than the size obtained by subtracting the thickness t5 of the electric element 265 from the thickness t3 or t4 or t3 + t4.

8 to 10 are top plan views of an organic light emitting display device according to an exemplary embodiment of the present invention. In the plan view of FIG. 8, the auxiliary electrodes 280a extend in a linear structure with respect to the plurality of pixels arranged in the same row. That is, the auxiliary electrodes 280a (n-2) and 280a (n) for each pixel arranged in a plurality of rows n-2, n-1, n, n + 1, n + 2, ... -1), 280a (n), 280a (n + 1), 280a (n + 2), ...) may be arranged.

In the plan view of FIG. 9, the auxiliary electrodes 280a extend in a linear structure with respect to the plurality of pixels arranged in the same column. That is, the auxiliary electrode for each pixel arranged in a plurality of columns (n-3, n-2, n-1, n, n + 1, n + 2, n + 3, n + 4, ...) 280a (n-3), 280a (n-2), 280a (n-1), 280a (n), 280a (n + 1), 280a (n + 2), 280a (n + 3), 280a (n + 4), ...) may be arranged.

In the plan view of FIG. 10, the auxiliary electrode 280a has a grid structure or a mesh structure around organic light emitting devices OLEDs having islands arranged regularly. The auxiliary electrodes 280a do not necessarily need to be electrically connected to each other. That is, in some sections, the auxiliary electrode 280a which is independently floating may be disposed according to a configuration requirement of the screen display unit.

These auxiliary electrodes 280a should not be shorted with an electrical element 265 such as a data line Data, a power line Vdd and a scan line, a source and a drain electrode, and a charging capacitor.

Hereinafter, a method of manufacturing an organic light emitting display device according to the present invention will be described with reference to FIGS. 4 to 7.

As shown in FIG. 4, the organic light emitting display device forms a thin film transistor (TFT) on the insulating substrate 200, and then covers the insulating layers 280 and 275 thereon, and the organic light emitting diode OLED and the auxiliary The electrode 280a is formed.

First, a buffer layer 210 is formed of SiO ₂ or the like on an insulating substrate 200 made of glass or plastic. When the buffer layer 210 is formed on the substrate 200, penetration of impurity elements is prevented and the surface is flat. The buffer layer 210 may be formed of SiO ₂ , and may be deposited by a PECVD method, an APCVD method, an LPCVD method, an ECR method, or the like, and may be deposited at about 3000 GPa. After the semiconductor active layer 221 is formed on the buffer layer 210, the semiconductor substrate is doped with ions to control the driving voltage, and the gate insulating layer 230 is formed on the semiconductor active layer 221. 241 is formed. After the interlayer insulating layer 250 is coated, the thin film transistor TFT is completed by forming a source / drain electrode 261 in contact with the semiconductor active layer 221 through a contact hole.

In more detail, the semiconductor active layers 221 and 222 may be formed of an inorganic semiconductor or an organic semiconductor, and may be formed to about 500 GPa. When the semiconductor active layers 221 and 222 are formed of polysilicon in the inorganic semiconductor, amorphous silicon may be formed and then polycrystallized by various crystallization methods. This active layer has source and drain regions heavily doped with N-type or P-type impurities, and has channel regions therebetween. The inorganic semiconductor may include CdS, GaS, ZnS, CdSe, CaSe, ZnSe, CdTe, SiC, and silicon materials such as a-Si (amorphous silicon) or poly-Si (poly silicon), and the organic semiconductor may be The bandgap may be formed of a semiconducting organic material having a range of 1 eV to 4 eV, and may include, for example, a polymer such as polythiophene or a low molecule such as pentacene.

A gate insulating film 230 is provided on the semiconductor active layer 221 by SiO _2, and the like, and a predetermined area on the gate insulating film 230 is formed of a conductive metal film such as MoW, Al, Cr, Al / Cu, or the like. 241 is formed. When the gate electrode 241 is formed, a first electrode, a scan line, or the like of the charging capacitor may be formed. The material forming the gate electrode 241 is not limited thereto, and various conductive materials such as a conductive polymer may be used as the gate electrode 241. The region where the gate electrode 241 is formed corresponds to the channel region of the semiconductor active layer 221.

An inter-insulator 250 is formed on the gate electrode 241 by SiO ₂ and / or SiN _x , and contact holes are formed in the inter-layer insulating film 250 and the gate insulating film 230. In this state, the source and drain electrodes 261 are formed on the interlayer insulating film 250. As the material for forming the source / drain electrodes 261 and 262, a conductive metal film such as MoW, Al, Cr, Al / Cu, conductive polymer, or the like can be used. When the source and drain electrodes 261 are formed, a wiring portion 265 such as a second electrode, a power supply line Vdd, a data line Data, and the like of the charging capacitor may be formed on the interlayer insulating layer 250. . The wiring unit 265 may be formed of the same material as the source and drain electrodes 261 or may be installed of a different material.

The structure of the thin film transistor as described above is not necessarily limited thereto, and all of the structures of the conventional general thin film transistor may be used as it is.

Next, on the insulating substrate, a first electrode 280 electrically connected to the source or drain electrode 261 of the thin film transistor is formed. The auxiliary electrode 280a is formed on the same layer as the first electrode 280. The first electrode 280 and the auxiliary electrode 280a are formed on the passivation film 270 and the planarization film 275 which are insulating layers on the thin film transistor.

The passivation film 270 is formed on the source / drain electrodes 261 by SiN _x , and the planarization film 275 is formed on the passivation film 270 by acrylic, BCB, polyimide, or the like. In this case, via holes 270a and 275a are formed in the passivation film 270 and the planarization film 275, which are insulating layers, to expose any one of the source and drain electrodes 261.

The first electrode 280 serving as the anode electrode is preferably made of a conductive material having a higher work function than the material of the second electrode 295 serving as the cathode electrode.

In order to emit light in a direction opposite to the substrate, the first electrode 280 is formed of a reflective film made of Ag, Mg, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, or a compound thereof. Thereafter, ITO, IZO, ZnO, or In ₂ O ₃ may be formed thereon. More preferably, the first electrode 280 and the auxiliary electrode 280a have a low specific resistance in order to minimize the voltage drop of the second electrode, and Al having excellent reflectance to increase the reflectance of the organic layer formed in a subsequent process. It is preferably made of a material that can be used as -ITO, Mo-ITO, Ti-ITO or Ag-ITO or other reflective film or anode electrode.

When emitting light in the direction of the substrate, the first electrode 280 may be formed of a transparent electrode made of ITO, IZO, ZnO, In ₂ O ₃ , or the like.

As described above, the first electrode 280 of the organic light emitting diode (OLED) is formed on the insulating layers 270 and 275, and the first electrode 280 is connected to the source and drain electrodes through the via holes 270a and 275a. To one of 261.

When forming the first electrode 280 and the auxiliary electrode 280a, first, an electrode material is applied onto an insulating substrate having the insulating layers 270 and 275, and then at least one edge of the position at which the auxiliary electrode 280a is to be formed. The insulating layers 270 and 275 are overetched accordingly. By overetching the insulating layers 270 and 275, grooves 280b having a predetermined depth t2 are formed in the insulating layers 270 and 275 along the edge of the auxiliary electrode 280a. At this time, it is preferable that over etching is performed by dry etching.

At the time of over etching, it is necessary to pay attention to the depth t2 of the groove 280b formed by over etching.

Referring to FIG. 6, which shows the periphery of the auxiliary electrode in more detail, the groove 280b has a depth t2 at the time of over etching, and the organic layers 290, 292 or 291 stacked on the groove 280b have a side surface of the auxiliary electrode 280a. It should be formed to be of sufficient depth so as not to cover it. For example, the depth t2 of the groove 280b is preferably at least larger than the thickness t1 of the auxiliary electrode 280a.

At the time of over etching, the deeper the depth t2 of the groove 280b is, the higher the possibility that the side surface of the auxiliary electrode 280a is not covered by the organic layers 290, 292 or 291 is preferable. However, the second electrode layer 295 should not be shorted with the electric element 265 such as the power line Vdd. Therefore, it is preferable that the depth t2 of the groove 280b is at least smaller than the thickness t3 or t4 or t3 + t4 of the insulating layers 275 and 270.

In particular, when the depth t2 of the groove 280b is large as shown in FIG. 7, attention should be paid more to overetching so that the electric element 265 does not overlap with the groove 280b. Therefore, when the electric element 265 including these wiring portions 265 is disposed below the groove 280b, the depth t2 of the groove 280b is at least the thickness of the insulating layers 275 and 270. It is preferable to be smaller than the size which subtracted the thickness t5 of the electric element 265 at t3 or t4 or t3 + t4).

Subsequently, a pixel defining layer 285 is formed to partition the first electrode 280. The pixel defining layer 285 is formed to cover the edge portion of the first electrode 280, so as not to cover the side surfaces of the first opening 285a and the auxiliary electrode 280a exposing a portion of the first electrode 280. It is formed to have a second opening 285b formed.

Thereafter, an organic layer is formed over the entire surface of the insulating substrate 200. As illustrated in FIG. 4, the organic layers 290, 291 and 292 including the emission layer 291 may be applied over the entire surface of the substrate as well as the first electrode 280. According to the needs of the manufacturing process, as shown in FIG. 5, the organic layers 290, 291 and 292 including the light emitting layer may be formed only on the first electrode 280, and the organic common layers 290 and 292 except the light emitting layer may be formed in other portions.

Thereafter, a second electrode 295 is formed to serve as a cathode electrode over the entire surface of the insulating substrate. At this time, due to the groove 280b formed along the edge of the auxiliary electrode 280a, the organic layers 290, 291 and 292 are not formed on the side surface of the auxiliary electrode 280a and are broken. Therefore, since the organic layers 290, 291, and 292 are not formed on the side surfaces of the auxiliary electrode 280a and are broken, the side surfaces of the auxiliary electrode 280a are electrically connected to the second electrode 295.

The second electrode 295 formed on the organic layers 290, 291 and 292 may be provided as a transparent electrode or a reflective electrode, and when used as a transparent electrode (for example, to emit light in a direction opposite to the substrate). The second electrode layer 63 has a metal having a small work function, that is, a thin metal layer made of Li, Ca, LiF / Ca, LiF / Al, Al, Mg, MgAg, and a compound thereof in the direction of the organic layer 290. After the deposition, a material for forming a transparent electrode such as ITO, IZO, ZnO, or In ₂ O ₃ may be formed thereon. And, when the second electrode 295 is used as a reflective electrode (for example, to emit light toward the substrate), Li, Ca, LiF / Ca, LiF / Al, Al, Mg, MgAg, and their The compound is formed by full deposition.

As described above, the organic light emitting display device and the manufacturing method thereof according to the present invention have the following effects.

First, it is possible to reduce the voltage drop of the upper electrode (for example, the cathode electrode) by using the auxiliary electrode line, thereby providing an organic light emitting display device having reduced luminance and image characteristics unevenness.

Second, by forming the auxiliary electrode at the same time as the lower electrode (for example, the anode electrode), it is possible to form a bus line to prevent the voltage drop of the cathode electrode without additional mask process.

Third, there is almost no defect in electrical connection with the cathode electrode through the side surface of the auxiliary electrode, so that very high reliability can be expected, and low power consumption and medium and large organic light emitting display devices can be realized.                     

As described above, the present invention has been described with reference to the most preferred embodiments, but the above embodiments are only for better understanding of the present invention, and the content of the present invention is not limited thereto. Even if there are additions, reductions, changes, modifications, and the like of some components of the composition of the present invention, it falls within the scope of the present invention as long as it belongs to the technical idea of the present invention defined by the appended claims.

For example, only one TFT is shown in the drawing, but in the actual planar structure, more TFTs may be arranged according to the circuit design, and the lower electrode is installed as an anode and the upper electrode is installed as a cathode, but the position is reversed. It is to be understood that those skilled in the art can easily design changes and fall within the equivalent scope of the present invention.

Claims (14)

An insulating substrate having an insulating layer; A first electrode formed on the insulating layer, and an auxiliary electrode formed on the same layer as the first electrode; A groove formed in the insulating layer having a predetermined depth along an edge of at least one side of the auxiliary electrode, wherein the depth is greater than the thickness of the auxiliary electrode and smaller than the thickness of the insulating layer; A pixel defining layer defining the first electrode; An organic layer formed on at least the first electrode layer and including a light emitting layer; And And a second electrode covering the organic layer and electrically connected to the auxiliary electrode. The method of claim 1, And the pixel defining layer is formed to expose a portion of the first electrode, the auxiliary electrode, and the groove. The method of claim 2, The organic layer includes an organic common layer other than the light emitting layer, and the organic common layer is provided to cover the auxiliary electrode and the groove. The method of claim 3, wherein And the second electrode is electrically connected to the auxiliary electrode through a side surface of the auxiliary electrode. delete delete The method of claim 1, And an electrical element including a wiring portion between the insulating layer and the insulating substrate, wherein the depth of the groove is such that the lower end of the groove does not touch the electrical element. The method of claim 7, wherein And the electric element is a thin film transistor electrically connected to the first electrode. The method according to any one of claims 1 to 4, And the auxiliary electrode has a linear structure. The method according to any one of claims 1 to 4, And the auxiliary electrode has a grid structure. Applying an electrode material onto an insulating substrate having an insulating layer; The electrode material is patterned to form an auxiliary electrode and a first electrode, and overetched along an edge of at least one side of the auxiliary electrode to form a groove in the insulating layer, the depth of which is formed when the groove is formed. Forming larger than the thickness and smaller than the thickness of the insulating layer; Forming a pixel defining layer to partition the first electrode; Forming an organic layer including a light emitting layer on at least the first electrode layer; And And forming a second electrode covering the organic layer and electrically connected to the auxiliary electrode through at least a side surface of the auxiliary electrode. delete delete The method of claim 11, And the over etching is such that the depth of the groove does not come into contact with an electric element including a wiring portion between the insulating layer and the insulating substrate.

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