KR100313885B1 - Organic Electro Luminescence Display - Google Patents

Abstract

PURPOSE: An organic electroluminescent display apparatus is provided to rapidly drive a large screen by preventing a RC component from being increased in proportion to a length of an electrode, and to reduce a voltage drop by remarkably decreasing the resistance of the electrode. CONSTITUTION: A plurality of the first electrode lines(12) are formed on a substrate(11) in the first direction. At least one organic electroluminescent layer(13) is formed on the substrate having the first electrode line. A plurality of the second electrode lines(14) are formed on the organic electroluminescent layer in a direction perpendicular to the first electrode line. The first electrode line or the second electrode line is lengthwise divided by two parts. The first and second connection pads are connected to the divided electrode lines exposed to both edges of the substrate so that each panel is divided by two parts and driven.

Description

Organic Electroluminescent Display Device

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device, and more particularly, to an organic electroluminescent display apparatus.

Recently, as the size of the display device increases, the demand for a flat display device having less space occupancy is increasing. As one of the flat display devices, an electroluminescent device is attracting attention.

The electroluminescent device is largely divided into an inorganic electroluminescent device and an organic electroluminescent device according to the material used.

In general, an inorganic electroluminescent device is a device that emits light by applying a high electric field to a light emitting part, accelerating electrons in the high electric field, and colliding with the light emitting center to thereby excite the light emitting center.

In addition, the organic light emitting device is based on the exciton generated by combining electrons and holes injected by injecting electrons and holes from the electron injection electrode (cathode) and the hole injection electrode (anode) into the light emitting unit, respectively. It is a device that emits light when falling into a state.

Since the inorganic electroluminescent device having the above operating principle requires a high electric field, a high voltage of 100 to 200 V is required as a driving voltage, whereas the organic electroluminescent device can be driven at a low voltage of about 5 to 20 V. There is an advantage, and research is being actively conducted.

In addition, the organic light emitting display device has excellent characteristics such as wide viewing angle, high speed response and high contrast, so it can be used as a pixel of a graphic display, a TV image display or a surface light source. They are thin, light, and have good color, making them suitable for next-generation flat panel displays.

However, there have been two problems in manufacturing a large area flat panel display using an organic light emitting display device having such a purpose.

The first is the voltage drop that occurs in the electrode strip direction due to the resistance of the electrode material and thus the difficulty of driving.

That is, in order to manufacture a large-area flat panel display, the length of the electrode becomes considerably longer, and thus the resistance R of the electrode becomes large, resulting in a large voltage drop. The response time is long.

Second, since the thickness of the organic light emitting layer is not uniform throughout, the brightness is not constant depending on the position.

That is, since the thickness of the organic light emitting layer affects the luminance of the device, the thickness of the organic light emitting layer should be formed to be uniform. However, as the display panel increases, the thickness becomes uneven.

Therefore, conventionally, in order to solve this problem, first, a plurality of organic light emitting diodes having a small panel of appropriate size are fabricated, and then the elements of the small panel are tiled on a large area plate. By attaching, a method of making a large display panel was used.

1 and 2 are structural cross-sectional views showing an organic light emitting display device according to the prior art, Figure 1 is a cathode 2, an organic light emitting layer 3, the cathode 4 is sequentially stacked on a transparent substrate (1) Attached organic electroluminescent elements on a large-area flat plate 5, and then electrically connecting side surfaces of the anodes 2 adjacent to each other by using a conductive adhesive 6, FIG. Although the structure is the same as in FIG. 1, instead of electrically connecting the sides of the anodes 2 adjacent to each other as shown in FIG. 1, the bottom surface of the anode 2 is electrically connected instead.

However, these conventional methods produce a large display panel by attaching a plurality of elements of a small panel, so that the thickness of the organic light emitting layer is uniform, thereby improving the brightness of the device. The voltage drop and thus the difficulty of driving still have not been solved.

This will be described in more detail as follows.

FIG. 3 is a view illustrating a structure of a general organic light emitting diode, and FIG. 4 is a view showing an equivalent circuit of a unit pixel and a light emission waveform thereof of a general organic light emitting diode.

3 and 4, the capacitance C depends on the relative permittivity of the organic light emitting layer, the thickness of the organic light emitting layer, the area of the pixel (active region), and the resistance R ₁ is determined by the organic light emitting layer. The resistive component and the resistive component between the organic electroluminescent layer and the electrode are shown. Finally, the resistor R ₂ represents the resistive component of the electrode and the wiring.

The RC time constant T of this equivalent circuit is

으로 나타낼 수 있다.

It can be represented as

In addition to the T, those contributing to the emission response time of the device include the time associated with the injection, transport, and bonding of charges (holes and electrons), and until the saturation level is reached after the start of emission. It is known that the time of the (rising time) and the like is associated with a significant portion of the capacitance C of the above equation.

The sum of all of these components is T ₁ shown in FIG. 4, where T ₁ represents the time from when the light is applied to the organic light emitting device until the light starts to reach the saturation level (the time when the light emission is completed).

In contrast, T ₂ represents the time from when the voltage is applied to the time when the light emission ends (the time when the light emission completely disappears).

The magnitudes of the response times T ₁ and T ₂ are very important variables for driving the organic electroluminescent display.

Although the unit pixels have been described so far, the actual display is composed of a plurality of pixels, and in the case of the XY simple passive matrix driving adopted in the present invention, the scan lines are generally driven sequentially and driven. Image information is simultaneously sent through the data line for each scanned line.

As the organic light emitting display becomes larger, the number of scan lines and data lines increases, and the length thereof becomes longer.

Accordingly, the turned-on cathode and anode bands cause the resistive component and the contribution of the organic electroluminescent layer capacitance of adjacent pixels to increase T ₁ and T ₂ .

On the other hand, as the number of scan lines increases, the dwell time per pixel decreases, so the number of scan lines and data lines that can be driven is limited.

The organic light emitting display device according to the prior art has the following problems.

When fabricating a large area flat panel display device, if the organic light emitting diodes of a small panel are arranged on the large area flat panel and the electrodes of the devices are connected, the length of the electrode becomes considerably longer, so the resistance (R) of the electrode becomes large and the voltage drop decreases. Becomes large, and the organic electroluminescent layer acts as a capacitor (C) to increase the RC to increase the response time (response time).

An object of the present invention is to provide an organic light emitting display device which can reduce a voltage drop occurring in an electrode strip direction.

1 and 2 is a structural cross-sectional view showing an organic light emitting display device according to the prior art

3 is a view illustrating a structure of a general organic light emitting display device

4 is a diagram illustrating an equivalent circuit of a unit pixel and a light emission waveform thereof of a general organic light emitting display device;

5 shows a typical simple matrix display panel.

6A to 6C are plan views illustrating a manufacturing process of the organic light emitting display device according to the present invention.

Explanation of symbols for main parts of the drawings

11 transparent substrate 12 first electrode

13: organic light emitting layer 14: second electrode

The main feature of the organic light emitting display device according to the present invention is that the electrode lines are formed on the display panel without being formed continuously, and are formed by separating them vertically or left and right, and as a result, the screen is driven to be separated vertically and / or left and right.

Another feature of the present invention is formed in the horizontal direction with a predetermined interval in the middle region of the transparent substrate, the left first electrode lines, the right first electrode lines formed on the left and right sides of the panel, the left and right first An organic electroluminescent layer formed on the front surface of the panel on which the electrode lines are formed, and an upper second formed on the organic electroluminescent layer so as to be orthogonal to the left and right first electrode lines, and separated into upper and lower portions of the panel, respectively; And electrode lines and lower second electrode lines.

The organic light emitting display device according to the present invention having the above characteristics will be described with reference to the accompanying drawings.

First, the concept of the present invention is that when forming the electrodes as shown in FIG. 6C without continuously arranging the electrodes from one end to the other end of the panel as in the general simple matrix display panel shown in FIG. The electrodes formed in the vertical direction of the panel are formed in two parts to be divided up and down, and the electrodes formed in the horizontal direction of the panel are formed in two parts to be divided to the left and right, and as a result, the screen is divided into four pixel groups. This results in driving, reducing the RC component along the length of the electrode line.

Hereinafter, the structure of the present invention having this concept will be described in more detail.

6A to 6C are plan views illustrating a manufacturing process of the organic light emitting display device according to the present invention. As shown in FIG. 6A, an indium tin oxide (ITO) thin film on the transparent substrate 11 is about 50 nm to 200 nm. After coating, a first electrode 12 having a stripe shape is formed through a photolithography process.

Here, the first electrode 1 is separated from the left and right electrode lines so as to be driven from the left and right sides of the panel without being connected at one end to the other end of the transparent substrate 11 at one time.

The reason why the first electrode 12 is separated into the left and right sides is that not only the pixels on the left and right sides can be driven, but also the RC component is reduced by that amount.

Subsequently, as shown in FIG. 6B, an organic light emitting layer (a hole transport layer, an organic light emitting layer, an electron transport layer, etc.) including a plurality of layers is formed on the substrate 11 on which the first electrode 12 is formed. Form.

As illustrated in FIG. 6C, metal materials such as Mg: Ag, Al: Li, and Al are formed on the organic light emitting layer 13 by a vacuum deposition method, and a shadow mask or a partition wall is used to form the metal material. The band-shaped second electrode 14 is formed by patterning a metal material.

Here, the second electrode 14 is not separated from one end to the other end of the transparent substrate 11 at one time, but is separated into electrode lines at the top and bottom of the panel so as to be driven at the top and bottom of the panel, respectively.

Although not shown, a protective film is formed on the front surface except for the ends of the first electrode 12 and the second electrode 14, and the first end of the first electrode exposed to the outside of the panel, that is, the first and second ends of the left and right ends of the panel. Pads for connecting to the driving circuit are formed in one electrode line, respectively. Similarly, pads for connecting the driving circuits are formed at the end of the second electrode exposed to the outside of the panel, that is, the second electrode line at the top and bottom ends of the panel.

In the present invention manufactured as described above, as shown in FIG. 6C, two electrodes are separated and formed on both sides of the panel, such that four pixel groups are formed in one panel.

Since the pads connected to the first and second electrode lines are connected to the driving circuits, respectively, the panel is divided into four parts to drive the result. Thus, the effective driving area of the panel, which was limited by the length of the conventional electrode line, was increased by four times. Get the result.

In the above embodiment, the first electrode and the second electrode are divided into two parts, and the panel is separated and driven into four parts. However, when only the first electrode is separated, the screen is divided into two parts separated left and right. When only two electrodes are separated, the screen is divided into two parts only by separating the screen up and down, and thus, a predetermined object according to the characteristics of the present invention can be achieved.

The organic electroluminescent display device according to the present invention has the following effects.

In order to reduce the length of the electrode line for driving the panel, the electrodes are formed to be separated into the left and right and / or up and down of the screen, and the screen is separated and driven so that an increase in the RC component proportional to the electrode length can be prevented. Not only can the screen run faster, but also the resistance of the electrode is greatly reduced, thereby reducing the voltage drop.

Claims (2)

A plurality of first electrode lines formed in a first direction on the substrate, at least one organic electroluminescent layer formed on the substrate on which the first electrode lines are formed, and formed on the organic electroluminescent layer and orthogonal to the first electrode lines In the organic light emitting panel consisting of a plurality of second electrode line, the first electrode line or the second electrode line is formed to be separated into two parts in the longitudinal direction, the separated electrode line exposed to both edges of the substrate An organic light emitting display device according to claim 1, wherein first and second connection pads are formed to drive the panel in two parts. A plurality of first electrode lines formed in a first direction on a substrate and at least one organic light emitting layer formed on the substrate on which the first electrode lines are formed, and a plurality of organic electrode emitting layers formed on the organic light emitting layer and orthogonal to the first electrode lines In the organic light emitting panel consisting of two second electrode lines, the first electrode line and the second electrode line is formed in each of two parts in the longitudinal direction, and the separated electrode line exposed to both edges of the substrate An organic light emitting display device, characterized in that the first to fourth connection pads are formed to drive the panel in four parts.

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