KR100902076B1 - Pixel circuit of organic electroluminescent device and manufacturing method thereof - Google Patents

Abstract

Disclosed are a pixel circuit of an organic electroluminescent device and a method of manufacturing the same. A gate electrode light blocking film and a gate line light blocking film formed on the transparent substrate, a gate electrode on the gate electrode light blocking film, and a gate line connected by the gate line light blocking film and the light blocking film contact portion. A light blocking film is formed on the substrate to block light incident from the outside, and a polysilicon pattern is formed on the light blocking film pattern to be insulated from the light blocking film pattern. A gate electrode is formed to be insulated from the polysilicon pattern, and a gate line is formed to be electrically connected to the light blocking film. In this way, the gate line of the pixel constituting the organic electroluminescent device is electrically connected to the light shielding film, thereby providing an extra gate line.

Description

Pixel circuit of organic electroluminescent device and manufacturing method thereof {PIXEL CIRCUIT OF ORGANIC ELECTROLUMINESCENCE DEVICE AND METHOD OF MANUFACTURING THE SAME}

1A is a plan view of one pixel circuit of an organic electroluminescent device according to an embodiment of the present invention.

FIG. 1B is a cross-sectional view taken along the direction A of FIG. 1A to describe one pixel circuit of an organic electroluminescent device according to an embodiment of the present invention.

2A to 2E are cross-sectional views cut along the direction A of FIG. 1 to explain a method of manufacturing an organic EL device according to an embodiment of the present invention.

3A to 3B are cross-sectional views of the organic electroluminescent device according to the exemplary embodiment of the present invention as viewed in the direction B of FIG. 1.

<Explanation of symbols for the main parts of the drawings>

200 substrate 210 gate electrode light shielding film

210a: gate line light shielding film 220: first insulating film

230: polysilicon pattern 240: second insulating film

250: opening 250a: light shielding film contact portion

260: gate electrode 260a: gate line

270: source / drain insulating film 275: capacitor                 

280a: data line 285: power supply line

280: source electrode 288: transistor

290: third insulating film 292: lower electrode

296: organic material layer 298: upper electrode

The present invention relates to a pixel circuit of an organic electroluminescent device and a manufacturing method thereof, and more particularly to a pixel circuit of an active organic electroluminescent device and a method of manufacturing the same.

As interest in flat panel displays increases, research on organic electroluminescence displays, which are low-voltage, high-brightness self-luminous displays, is being actively conducted. The organic electroluminescent display can form various materials by synthesizing the organic material by forming a light emitting layer that generates light by itself as an organic material. In addition, since the organic material is deposited at a low temperature, it can be manufactured by a low temperature manufacturing process, and can be driven at a low voltage to improve the luminous efficiency of the display.

In general, the organic electroluminescent display includes an organic material layer including a hole transporting layer (HTL), an emission layer, and an electron transporting layer (ETL) on a transparent substrate on which a transparent electrode is formed. It is a bottom emission structure in which a metal electrode is formed on the top.

According to the driving method of the organic electroluminescent display, a passive matrix organic electroluminescence device (PMOELD, hereinafter referred to as "PMOELD") and an active matrix organic electroluminescence device (Active Matirx Organic Electroluminescence Device); AMOELD, hereinafter referred to as "AMOELD".

In the PMOELD driving method, an anode of a lower electrode patterned in a line form and a cathode of an upper electrode patterned in a line form intersect with each other so as to be orthogonal to the anode may be selectively designated and driven. do. However, in order to emit light of one pixel, which is the minimum unit of the display device, a current must be applied to the entire electrode in the form of a line including the pixel. Of consumption occurs. As the area of the display increases, the resistance problem caused by the line of the electrode becomes more severe. In addition, when the current applied to each pixel becomes inconsistent, the color implementation of the entire display is not uniform, and the function as the display is not properly executed.

In contrast, the AMOELD driving method can control the pixels individually by using thin film transistors. Accordingly, the display can be driven using less current than the PMOELD driving method, and even when the characteristics are different for each pixel, a uniform color can be realized throughout the display by using the compensation current by the circuit design.                         

However, if any of the gate lines constituting the circuit is defective, the pixels supplied with the current by the gate lines are not driven and thus cannot implement the entire display normally. In order to prepare for such defects, an extra gate line is required. However, when the organic electroluminescent device includes an extra gate line like a semiconductor element, a circuit area increases in a predetermined pixel area. Therefore, the area of the opening capable of emitting light to the outside per pixel is relatively reduced, and the aperture ratio, which is the ratio of the light emitting area to the pixel area, is significantly reduced. Even if a spare gate line is provided, if the number of spare gate lines is smaller than the number of defective gate lines, the gate line cannot be used as a display device. Thus, there is a limit in preparing a defective gate line.

Accordingly, it is a first object of the present invention to provide a pixel circuit of an organic electroluminescent device having a spare gate line.

It is a second object of the present invention to provide a method of manufacturing a pixel circuit of an organic electroluminescent device provided with the gate line for the margin.

A pixel circuit of an organic electroluminescent device for achieving the first object includes a gate electrode light shielding film and a gate line light shielding film formed on a transparent substrate, a gate electrode on the gate electrode light shielding film, and a gate connected by the gate line light shielding film and the light shielding film contact portion. It includes a line.                     

A method of manufacturing a pixel circuit of an organic electroluminescent device for achieving the second object includes forming a light shielding film for blocking light incident from the outside on a substrate, and forming a first insulating layer on a resultant on which the light shielding film pattern is formed. Forming a polysilicon pattern on the first insulating layer formed on the light shielding film pattern; forming a second insulating layer on the resultant including the polysilicon pattern; Forming a gate line on the insulating layer to be electrically connected to the gate electrode and the light blocking film.

According to such a pixel circuit of the organic electroluminescent device and a method of manufacturing the same, the gate line of the pixel constituting the organic electroluminescent device is electrically connected to the light shielding film, so that an additional gate line can be provided.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1A is a plan view of one pixel circuit of an organic electroluminescent device according to an embodiment of the present invention.

Referring to FIG. 1A, a gate line 260a travels in a first direction on a substrate and a data line 280a travels in a second direction perpendicular to the first direction. A light blocking film (not shown) connected to the gate line 260a is provided under the gate line 260a through the light blocking film contact part 250a. A transistor 288 connected to the gate line 260a and the data line 280a is present at the intersection of the gate line 260a and the data line 280a constituting one pixel. The capacitor 275 in contact with the transistor 288 and the power supply line 285 is positioned at a position adjacent to the transistor 288. The number of transistors can be selectively adjusted according to the current supply characteristics of the device.

FIG. 1B is a cross-sectional view taken along the direction A of FIG. 1 to explain an organic electroluminescent device according to an embodiment of the present invention.

Referring to FIG. 1B, a gate electrode light blocking film 210 and a gate line light blocking film 210a exist on the transparent substrate 200. The first insulating layer 220 partially exposing the top surface of the gate line light blocking film 210a is positioned on the resultant product. A polysilicon pattern 230 is positioned on the first insulating film 220 on the gate electrode light blocking film 210, and a second insulating film exposing the same region as the first insulating film 220 on the resultant product. 240) is present. The light blocking layer contact part 250a is positioned in an area exposed by the first and second insulating layers 220 and 240. A gate line 260a is present on the light blocking film contact part 250a, and a gate electrode 260 is present on the second insulating layer 240 while being spaced apart from the gate line 260a by a predetermined interval. The source electrode 280 is disposed on the gate electrode 260 with the source / drain insulating layer 270 uniformly extended to the gate line 260a interposed therebetween.

2A to 2E are cross-sectional views cut along the direction A of FIG. 1 to explain a method of manufacturing an organic EL device according to an embodiment of the present invention.

Referring to FIG. 2A, a metal film such as chromium (Cr) is deposited on a transparent substrate 200 such as glass to form a metal film. By patterning the metal film, a gate electrode light blocking film 210 and a gate line light blocking film 210a are formed. The gate electrode light shielding film 210 and the gate line light shielding film 210a prevent photoelectric currents from flowing in the device by generating a photocurrent of a material that is subsequently formed by a transistor due to light incident from the outside.

Since the materials forming the gate electrode light blocking film 210 and the gate line light blocking film 210a are conductive, the first insulating film 220 may be uniformly insulated from the gate electrode light blocking film 210 and the gate line light blocking film 210a. Form.

An amorphous silicon film (not shown) is formed on the first insulating film 220. When the organic electroluminescent device is driven using the amorphous silicon film, the lifetime of the device is shortened due to deterioration of the device, so that the amorphous silicon film is processed to be changed into a polysilicon film (not shown) by changing the crystal arrangement.

The polysilicon layer is patterned to form a polysilicon pattern 230 on the gate electrode light blocking layer 210. The polysilicon pattern 230 may be adjusted as necessary according to the number of transistors to be formed. A second insulating layer 240 may be formed on the resultant including the polysilicon pattern 230 to insulate the polysilicon pattern 230.

3A to 3B are cross-sectional views of the organic electroluminescent device according to the exemplary embodiment of the present invention as viewed in the direction B of FIG. 1.

2B and 3A, a portion of the second insulating layer 240 on the gate line light blocking layer 210a is etched, and the second insulating layer 240 is etched to form an upper portion of the first insulating layer 220. Expose An opening 250 is formed to etch the exposed first insulating layer 220 to expose an upper surface of the gate line light blocking layer 210a.

2C and 3B, the light blocking film contact portion 250a connected to the gate line light blocking film 210a by coating a metal material on the second insulating film 240 including the bottom and side surfaces of the opening 250 is formed. Is formed. The coated metal material is patterned to form a gate electrode 260 on the polysilicon pattern 230. At the same time, a gate line 260a is formed at a position spaced apart from the gate electrode 260 to cross one surface of the pixel where the light blocking layer contact portion 250a is located.

As such, the light blocking film contact portion connected to the gate line light blocking film 210a is formed under the region where the gate line 260a is formed, so that the gate line 260a is electrically connected to the gate line light blocking film 210a made of the conductive material under the gate line 260a. Is connected.

Therefore, after the fabrication of the device is completed, an electrical defect occurs in the gate line 260a, and thus electrical flow occurs to the lower gate line light blocking film 210a connected to the gate line 260a even when electrical conduction is impossible. Therefore, a normal display can be realized by driving the device. That is, in order to prepare for the occurrence of the failure of the gate line 260a, additionally, the gate line margin is additionally formed to reduce the opening ratio of the device and use the light shielding film to replace the failure of the gate line without additional processing. The wiring can be secured.

Referring to FIG. 2D, source / drain regions (not shown) are ion-doped with respect to the polysilicon patterns 230 on the lower left and right sides of the gate electrode 260. A source / drain insulating layer 270 is formed on the resultant. A source electrode 280 connected to a source region (not shown) of the polysilicon pattern 230 is formed through the source / drain insulating layer 270 to operate a transistor by receiving a current. A third insulating film 290 is formed to insulate the resultant product.

Referring to FIG. 2E, the lower electrode 292 electrically connected to the circuit part on the resultant material, the organic layer 296 and the upper electrode 298 made of a material capable of self-emission by holes and electrons when a current is applied. ) In order.

As described above, according to the present invention, the light blocking film made of metal and the gate line running along one surface of the pixel are formed to be electrically connected by the contact portion.

In this way, by conducting the gate line of the pixel constituting the organic electroluminescent device with the light shielding film, an extra gate line can be provided without increasing the circuit portion area of the pixel. Therefore, even when a defect occurs in the gate line of the pixel, a current may be applied using a light shielding film connected to the defective gate line. In other words, it is possible to reduce the occurrence of defects of the device to improve the yield.

As described above, although described with reference to a preferred embodiment of the present invention, those skilled in the art will be variously modified without departing from the spirit and scope of the invention described in the claims below. And can be changed.

Claims (4)

A gate electrode light shielding film and a gate line light shielding film formed on the transparent substrate; An insulating film including an opening exposing the gate line light blocking film; A polysilicon pattern disposed on the gate electrode light shielding film; A gate electrode disposed on the polysilicon pattern; And And a gate line electrically connected to the gate electrode and electrically connected to the gate line light blocking layer through the opening. Forming a light shielding film for blocking light incident from the outside on the substrate; Forming a first insulating layer on the resultant product in which the light shielding film is formed; Selectively forming a polysilicon pattern on the first insulating layer formed on the light blocking film; Forming a second insulating layer on the resultant including the polysilicon pattern; And Forming a gate line on the second insulating layer so as to be electrically connected to the gate electrode and the light blocking film. The method of claim 2, wherein the forming of the gate line comprises: Etching portions of the second and first insulating layers in sequence to form openings to expose the top surface of the light blocking film; Forming a gate line contact by uniformly applying a metal film on the second insulating layer including the bottom and side surfaces of the opening; And Patterning the metal layer to form a gate line on the polysilicon pattern so as to be spaced apart from the gate electrode and the polysilicon pattern at a predetermined distance and to be connected in one direction while being connected to the gate line contact; Method of forming a pixel circuit of a device. The method of claim 2, wherein the light shielding film is made of chromium.

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