KR20020029715A - Organic electroluminescence display device - Google Patents

Abstract

PURPOSE: An organic electroluminescence display device is provided to achieve an improved display quality and reduce power consumption by maintaining contact resistances of cathode side lead electrodes at both sides of screen display area to be equal. CONSTITUTION: An organic electroluminescence display device comprises a substrate(110); anode electrodes(120) arranged at a screen display area from among the upper surface of the substrate; anode side lead electrodes arranged outside of the screen display area and connected to ends of anode electrodes so as to apply power to anode electrodes; cathode side lead electrodes(165a,165b) arranged at the opposed one side and the other side of the screen display area, and which are separated from the anode electrodes; an inter-layer insulation film(130) covering the front surface of the substrate, and which has contact holes(127,167a,167b) formed at a predetermined portion of the cathode side lead electrodes disposed adjacent to the screen display area and at a predetermined portion of anode electrodes where pixels are to be formed; a luminescent element layer for generating light having a predetermined color; and cathode electrodes arranged to cross the anode electrodes and connected to cathode side lead electrodes through contact holes.

Description

Organic electroluminescence display device

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic light emitting display device, and more particularly, an interlayer insulating film is formed on the entire surface of the substrate to cover the lead electrodes, and predetermined portions of the cathode side lead electrodes formed on both sides of the screen display area of the interlayer insulating film. After forming a contact hole in the cathode, the cathode is formed to electrically connect the cathode-side lead electrodes and the cathode electrodes through the contact hole, thereby controlling the contact area of the cathode-side lead electrodes formed on both sides of the screen display area equally. An organic electroluminescent display device is provided.

CRT (Cathode Ray Tube), one of the commonly used display devices, is mainly used for monitors such as TVs, measuring devices, and information terminal devices.However, due to the weight and size of the CRT itself, Could not respond actively to the demand.

In order to replace the CRT, development of a flat panel display device having advantages such as light and small size and low power consumption is actively progressing, and the demand thereof is continuously increasing. Until now, the demand for a liquid crystal display device for displaying information using the electro-optical properties of liquid crystals among flat panel display devices is the highest, and thus technology development has been focused on liquid crystal display devices.

However, since the liquid crystal display device is a light-receiving device that displays an image by controlling the amount of light coming from the outside, driving is complicated, and a separate light source, that is, a backlight assembly, for irradiating light to the liquid crystal panel is necessary, so that the liquid crystal display is required. There are a number of disadvantages in many ways, such as smaller and smaller devices and price competitiveness.

As a result, in recent years, the development of an organic light emitting display device, which is a self-luminous device capable of easily realizing light and small size, has a rapid response speed, excellent luminance, and simple structure compared to a liquid crystal display device. The organic electroluminescent device is attracting attention as a next-generation flat panel display device following the liquid crystal display device due to its various uses such as a backlight of a liquid crystal display device, a portable terminal, an automobile navigation system, a laptop computer, and a wall-mounted TV.

The organic light emitting display device forms a light emitting element layer that emits light between an anode electrode to which positive power is applied and a cathode electrode to which negative power is applied, and holes and cathode electrodes transferred from the anode electrode to the light emitting element layer. When the electrons transferred to the light emitting device layer recombine at, organic molecules forming the light emitting device layer are excited, and excitons are emitted, and the emitted excitons are inactivated to emit light from the light emitting layer.

The structure of the organic light emitting display device will be described with reference to FIG. 1 as follows.

First, ITO is deposited on a transparent substrate 10 that transmits light, and then patterned ITO to form anode electrodes 20 to which positive power is applied to the screen display area, which is a part where a screen is displayed. Anode side lead electrodes (not shown) and cathode side lead electrodes 65a and 65b are formed on the outside. Here, the anode side lead electrodes extend from one end of the anode electrodes 20, and the cathode side lead electrodes 65a and 65b are positioned at one side in the width direction of the anode electrode 20 and the anode electrode 20. It is formed to be spaced apart from a predetermined interval. According to the specification of the product, as shown in FIG. 1, cathode side lead electrodes 65a and 65b may be formed on both sides of the screen display area, and cathode side lead electrodes 65a, The organic electroluminescent display 1 in which 65b) is formed will be described.

As such, when the anode electrodes 20, the anode side lead electrodes, and the cathode side lead electrodes 65a and 65b are formed on the substrate 10, the anode side lead electrodes and the cathode side lead electrodes 65a and 65b are formed. In order to prevent corrosion by this external environment and obtain proper electrical characteristics, anode lead electrodes and cathode lead electrodes as shown in FIG. 1 using metals such as Cr, Ni, Ag, Au, and Mo The protective electrode 21 is formed only on the upper surfaces of the 65a and 65b.

Subsequently, an interlayer insulating layer 30 that insulates the lower layer and the upper layer is formed only in the screen display area, and a contact hole is formed only in a portion (pixel portion) of the interlayer insulating layer 30 where light is emitted to display the screen. A predetermined portion of 20 is exposed to the outside of the interlayer insulating film 30.

Then, the photoresist is thickly coated on the entire surface of the substrate 10, and the photocathode and etching processes are performed on the opposite cathode side lead electrodes across the screen display area from a predetermined portion of the cathode side lead electrodes 65a. 65b) Cathode separation partitions 40 extending to a predetermined portion are formed in the space between the cathode side lead electrodes 65a and 65b.

Subsequently, the light emitting portion emits light by flowing a current by depositing an organic material on the screen 10 by closely attaching a mask (not shown) that has a portion corresponding to the screen display area and a closed area to the substrate 10. The element layer 50 is formed.

Subsequently, by depositing a cathode metal in a state in which an open mask (not shown) is brought into close contact with the substrate 10 so that the screen display area and predetermined portions of one end portions of the cathode side lead electrodes 65a and 65b are exposed. Cathode electrodes 60 intersecting with the anode electrodes 20 are formed in the space between the cathode separation barrier ribs 40. At this time, since the opening of the mask is formed to expose the predetermined portion of one side end of the cathode side lead electrodes 65a and 65b, when the cathode metal is deposited on the substrate 10, the cathode side lead electrodes 65a and 65b and the cathode side lead electrodes 65a and 65b are formed. The cathode electrodes 60 are naturally connected.

However, in the process of depositing the cathode metal to form the cathode electrodes 60 as well as connecting the cathode electrodes 60 and the cathode side lead electrodes 65, the mechanical mask is shaken, which is illustrated in FIG. As described above, the contact areas l ′ of the cathode side lead electrodes 65b formed on the opposite side of the cathode side lead electrodes 65a formed on one side of the screen display area are different from each other.

When the contact areas of cathode side lead electrodes formed on both sides of the screen display area are different from each other, the contact resistance is different, resulting in luminance unevenness and power consumption. have.

Accordingly, an object of the present invention is that despite the shaking of the mask, the contact area of the cathode lead electrodes formed on one side of the screen display area with respect to the screen display area and the contact area of the cathode lead electrodes formed on the other side of the screen display area. To control the same.

Other objects of the present invention will become more apparent from the following detailed description and the accompanying drawings.

1 is a cross-sectional view schematically illustrating a structure of a conventional organic light emitting display device.

2A and 2B illustrate a process of forming anode electrodes and lead electrodes in an organic light emitting display device according to the present invention.

3A and 3B illustrate a process of forming contact holes in an interlayer insulating film and an interlayer insulating film in an organic light emitting display device according to an exemplary embodiment of the present invention.

4 is a cross-sectional view illustrating a state in which cathode separation barriers are formed in an organic light emitting display according to the present invention.

5 is a cross-sectional view illustrating a state in which a light emitting device layer is formed in an organic light emitting display according to the present invention.

6A and 6B are cross-sectional views illustrating a process of forming a cathode electrode while cutting FIG. 3B by A-A, and connecting the cathode electrode and the cathode side lead electrodes.

7A and 7B are cross-sectional views illustrating a process of forming a cathode electrode while cutting FIG. 3B into B-B and connecting a cathode electrode and a cathode side lead electrode.

In order to achieve the above object, the present invention forms an interlayer insulating film on the entire surface of the substrate on which the cathode lead electrodes are formed on both the anode electrodes and the screen display area, and a portion of the interlayer insulating film on which a pixel is to be formed and one end of the cathode lead electrodes. A light emitting element layer is formed after forming a contact hole of a predetermined size in the cathode, and the cathode metal including the screen display area is formed in close contact with the substrate by forming a mask in which an opening for exposing predetermined portions of the end portions of the cathode-side lead electrodes is formed. By depositing the cathode, the cathode and the cathode-side lead electrodes are electrically connected through the contact holes formed at the ends of the cathode-side lead electrodes.

Hereinafter, an organic light emitting display device according to the present invention will be described with reference to FIGS. 2A to 7B.

As shown in FIGS. 2A, 7A, and 7B, an organic light emitting display device includes anodes formed on a screen display area among upper surfaces of the substrate 110 and upper surfaces of the substrate 110, and having positive power supplied thereto. 120, lead electrodes 125 (165a and 165b) formed outside the screen display area and electrically connecting the external driving device (not shown) to the electrodes, a portion where the pixel is to be formed, and the lead electrodes 165a. A contact hole 127 (167a, 167b) is formed at a predetermined end portion of the 165b and insulates the anode electrodes 120 and other electrodes to be formed on the anode electrodes 120; It is formed between the cathode separation barrier ribs 140 and the cathode separation barrier ribs 140 extending from a predetermined portion of the lead electrodes 165a and 165b to the screen display area to generate light by current flow. Top surface of the light emitting element layer 150 and the light emitting element layer 150 And cathode electrodes 160 formed to intersect the anode electrodes 120 and connected to the lead electrodes 165a and 165b through the contact holes 167a and 167b.

Among these components, the anode electrodes 120 are formed in a stripe shape along the longitudinal direction of the substrate 110 by being spaced apart from each other as shown in FIG. 2A.

In addition, the lead electrodes 125 and 165a and 165b include the anode side lead electrodes 125 and the cathode side lead electrodes 165a and 165b as illustrated in FIG. 2A. The anode side lead electrodes 125 are connected to the anode electrodes 120 to supply positive power to the anode electrodes 120, and the longitudinal direction of the substrate 110 is extended from one end of the anode electrodes 120. As a result, it extends by a predetermined length.

The cathode lead electrodes 165a and 165b are connected to the cathode electrodes 160 through the contact holes 167a and 167b to supply negative power to the cathode electrodes 160. It is formed on one side and the other side of the direction, and is spaced apart from the anode electrode 120 by a predetermined interval.

As shown in FIG. 2B, upper surfaces of the anode-side lead electrodes 125 and the cathode-side lead electrodes 165a and 165b may be provided to protect lead electrodes from corrosion by an external environment and to improve electrical characteristics. 121 is formed.

Meanwhile, the interlayer insulating layer 130 electrically insulates the anode electrodes 120 and the cathode electrodes 160 and is formed on the entire surface of the substrate 110. As described above, the contact holes 127 and 167a and 167b are formed at portions of the side where the pixel is to be formed and at one end of the cathode side lead electrodes 165a and 165b, respectively, and thus, the predetermined portions of the anode electrodes 120. And a predetermined portion of the cathode side lead electrodes 165a and 165b are exposed to the outside of the interlayer insulating layer 130.

Preferably, the contact holes 167a and 167b formed in the cathode side lead electrodes 165a and 165b are in contact with the cathode side lead electrodes 165a formed on one side of the screen display area and the cathode electrodes 160. Range in which the mask 200 (see FIGS. 6A and B) is shaken by mechanical tolerances so that the area may be equal to the contact area of the cathode electrodes 160 of the cathode side lead electrodes 165b formed on the other side of the screen display area. To form.

The cathode separation barriers 140 are used to cleanly separate the light emitting device layer 150 and to prevent the cathode electrodes 160 adjacent to each other from being short-circuited. Among the lead electrodes, cathode side lead electrodes 165a and 165b. It is formed in inverted trapezoidal shape in space between)

The method of manufacturing the organic EL device configured as described above will be described with reference to FIGS. 2A to 7B.

First, a transparent metal that transmits light, for example, ITO, is deposited on the upper surface of the substrate 110, and then ITO is patterned using photolithography and etching techniques. Then, the anode electrodes 120 are formed in a stripe shape along the longitudinal direction of the substrate 110 in the screen display area of the upper surface of the substrate 110 by being spaced apart from each other by a predetermined distance, and the lead electrode outside the screen display area. Fields 125 (165a, 165b) are formed.

Here, anode side lead electrodes 125 are formed at one side in the longitudinal direction of the anode electrodes 120 and are connected to the anode electrodes 120, and cathode side lead electrodes (at the side in the width direction of the anode electrode 120) 165a and 165b are formed in a line, and cathode side lead electrodes 165a and 165b are formed on one side and the other side of the screen display area facing each other and are separated from the anode electrodes 120.

As described above, when the anode electrodes 120 and the lead electrodes 126 (165a and 165b) are formed, a predetermined metal is deposited on the substrate 110, and then the predetermined metal is patterned, as shown in FIG. 2B. The protective electrode 121 is formed only on the upper surfaces of the lead electrodes 125, 165a and 165b.

Preferably, after the ITO and the predetermined metal are deposited on the substrate 110 in sequence, the predetermined metal is patterned to form the passivation layer 121 at the portions where the lead electrodes 125, 165a and 165b are to be formed. Afterwards, the ITO may be patterned to form the anode electrodes 120 and the lead electrodes 125 (165a and 165b).

When the protective electrode 121 is formed by the above-described process, as shown in FIG. 3A, a predetermined insulating material is coated on the entire surface of the substrate to form the interlayer insulating layer 130, and the cathode side as shown in FIG. 3B. Cathode-side leads are formed by forming contact holes 127 (167a and 167b) having predetermined sizes in one end portions of the lead electrodes 165a and 165b and the portions in which pixels for displaying information are formed among the anode electrodes 120. FIG. Exposed portions of the electrodes 165a and 165b and the anode electrodes 120 are exposed to the outside of the interlayer insulating layer 130.

Afterwards, the photoresist is thickly applied, and through the photolithography process and the etching process, cathode separation barrier ribs intersecting with the anode electrodes 120 in the space between the cathode side lead electrodes 165a and 165b as shown in FIG. 4. The cathode separation partitions 140 are formed in an inverted trapezoidal shape, and are formed on opposite sides of the cathode display lead electrodes 165a formed on one side of the screen display area across the screen display area. The cathode side lead electrodes 165b extend to predetermined portions.

Subsequently, a mask (not shown) which exposes only the screen display area and closes the rest is in close contact with the substrate 110, and then, an organic material emitting a predetermined color is deposited to emit light by the flow of current. ) Is formed in the screen display area as shown in FIG.

6A and 6B, the opening 210 may be exposed to a predetermined portion of the cathode-side lead electrodes 165a and 165b including the screen display area and having the contact holes 167a and 167b formed thereon. Is formed and the remaining portion deposits the cathode metal in a state where the closed mask 200 is in close contact with the substrate 110. Then, as shown in FIGS. 7A and 7B, the cathode electrodes 160 crossing the anode electrodes 120 are formed in the space between the cathode separation barriers 140 and the cathode electrodes 160 and the cathode electrodes 160. The cathode side lead electrodes 165a and 165b are connected through the contact holes 167a and 167b.

In the process of forming the cathode electrodes 160, the end points of the openings 210 to be positioned at the reference points a and a 'are moved to the outside and inside of the reference points a and a' due to the shaking of the deposition mask 200. That is, the end point of the opening 210 to be positioned at the reference point a goes out of the reference point a by a predetermined length as shown in FIG. 6A, and the end point of the opening 210 to be positioned at the reference point a 'is shown in FIG. 6B. As shown in the drawing, a predetermined length enters the inside of the reference point a '.

However, since the contact holes 167a and 167b formed at one end of the cathode side lead electrodes 165a and 165b are formed within the shaking error range of the mask, the cathode metal is formed as shown in FIGS. 7A and 7B. It will completely fill 167a, 167b.

Therefore, despite the shaking of the mask 200, the contact area between the cathode side lead electrodes 165a and the cathode electrodes 160 formed on one side of the screen display area is the cathode side lead electrode formed on the other side of the screen display area. The contact area between the electrodes 165b and the cathode electrodes 160 is the same. This is because the areas of the contact holes 167a and 167b formed at one end of the cathode side lead electrodes 165a and 165b are all the same.

As described above, an interlayer insulating film is formed on the entire surface of the substrate, and contact holes are formed within the mechanical fluctuation error range of the deposition mask among cathode side lead electrodes connected to the cathode electrodes. The contact areas of the formed cathode side lead electrodes and the cathode electrode are controlled to be equal to each other.

Then, since the contact resistances of the cathode electrodes connected to the cathode side lead electrodes formed on one side of the screen display area and the cathode resistances connected to the cathode side lead electrodes formed on the other side of the screen display area are the same, the organic electroluminescence The display quality of the display device can be improved and the power consumption can be reduced.

Claims (3)

A substrate that transmits light; A plurality of anode electrodes formed on the screen display area, which is a part of the upper surface of the substrate, spaced apart from each other by a predetermined distance; Anode side lead electrodes formed outside the screen display area and connected to one ends of the anode electrodes to apply power to each of the anode electrodes; Cathode side lead electrodes formed on one side and the other side of the screen display area facing each other among the outside of the screen display area and separated from the anode electrodes; An interlayer insulating layer covering a front surface of the substrate and having contact holes formed in a predetermined portion of one end of the cathode-side lead electrodes adjacent to the screen display area and a predetermined portion of the anode to display pixels; A light emitting element layer formed on the same line as the cathode side lead electrodes in the screen display area and generating light having a predetermined color; And organic light emitting diodes formed on the same line as the cathode side lead electrodes in the screen display area to cross the anode electrodes and connected to the cathode side lead electrodes through the contact holes. Display. The organic field of claim 1, wherein the area of the contact holes formed in the cathode side lead electrodes is the same, and the contact holes are formed within an error range of a mask used when the cathode electrodes are formed. Light emitting display. The display device of claim 1, further comprising: extending from a predetermined portion of the cathode side lead electrodes formed on one side of the screen display area to a predetermined portion of the cathode side lead electrodes formed on the other side of the screen display area across the screen display area. An organic light emitting display device, wherein cathode separation barriers are further formed in a space between the cathode side lead electrodes.