KR20050100133A - Method for aging of organics electroluminunce device - Google Patents

Abstract

The present invention is to provide an aging method that can improve the reliability of the organic EL panel by performing the aging treatment in the initial step of depositing a second electrode (cathode), at least one of the first electrode and the second electrode In the aging method of the device for emitting an organic layer having a light emitting layer by applying a voltage, in the initial step of forming the second electrode in a vacuum chamber, a reverse voltage or a reverse current is applied between the two electrodes, This is to perform an aging treatment to remove the shorting portion that causes it.

Description

Method for aging of organics electroluminunce device

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aging method of an organic EL element, and more particularly to a method of improving the reliability of an organic EL panel using a technique of aging while depositing a cathode electrode.

An organic EL device is a device that emits light by dissipating electrons and holes after pairing with an organic film formed between an electron injection electrode (cathode) and a hole injection electrode (anode), and can be driven at a low voltage. In addition, the device is characterized in that the power consumption is relatively low.

As shown in FIG. 1, a display panel using such an organic EL device is initially cleaned of a glass material substrate (S10), and then an indium tin oxide (ITO) transparent electrode and an auxiliary electrode, which is a first electrode, are formed on the substrate. Producing an electrode (S20). Subsequently, an insulating film and a partition wall are fabricated on the auxiliary electrode (S30).

In this case, the first electrode, the auxiliary electrode, the insulating film, and the partition wall are manufactured by a photolithography process.

Next, after cleaning the entire surface (S40) and performing a surface treatment (S50), the multilayer organic film (hole injection layer, hole transport layer, light emitting layer, electron transport layer) (S60) on the surface treated surface, and aluminum as a second electrode (aluminum) are sequentially stacked (S70).

In this case, the multilayer organic film and the second electrode are manufactured by thermal evaporation.

By the way, the organic EL device configured as described above is manufactured by a method such as evaporation or sputtering in a clean room. In this process, foreign matters of various sizes are generated. This greatly deteriorates the reliability of the organic EL element.

Since the thickness of the multilayer organic film is generally about 5 nm to 200 nm, when foreign materials of several um size are mixed at several tens of nm during the fabrication process and exist between the ITO electrode, which is the first electrode, and the Al electrode, which is the second electrode, It causes short and leak currents.

Therefore, in order to solve this problem, after the second electrode (cathode) is formed, a so-called "aging" process of applying a voltage or a current between the two electrodes to repair the defective part is often used.

That is, after depositing the organic material and the second electrode (cathode) on the substrate (S70), in the semi-finished state in which the encapsulation process is completed (S80), a fixed voltage or current is applied to repair the defective portion (repair). Aging processing is performed (S90).

And finally assembled to produce a finished product (S100).

As described above, the organic EL device divides the first electrode and the second electrode of the organic panel or each of the first electrodes or the second electrodes by two or more through an aging process, and exchanges the voltage or current in the forward and reverse directions between the same electrodes. The foreign material is removed by repeatedly applying AC) or direct current (DC).

In this case, when the voltage or current applied for the aging process is too low, the repair effect is small, and when the voltage or current is too high, the explosion may occur at a defective part, causing the panel to deteriorate or be damaged.

As described above, the degree of recovery in the aging process is highly dependent on the voltage applied during aging (especially reverse voltage), and it is very important to define the magnitude of the voltage during the aging process.

However, the size and composition of foreign matters mixed during the fabrication of the organic EL panel are generated in various ways. The voltage used in the aging method currently used is set to a specific voltage having a certain size, and uniformly using the set specific voltage. Aging is in process.

Therefore, if the size of the set voltage is too low than the size of the voltage required to recover the foreign substance and components to be mixed, the portion of the foreign substance that is not recovered is generated as a defective portion, and also the size of the foreign substance mixed with If the magnitude of the set voltage is too high than the magnitude of the voltage required for the component to recover, the defective portion is excessively destroyed, causing deterioration of the panel.

As described above, when the aging treatment is performed using a specific voltage set to a constant voltage in the aging method, the aging treatment may or may not be recovered depending on the component and size of the foreign matter mixed during the manufacture of the organic EL panel. In the case of the organic EL panel, the reliability is greatly reduced.

In this case, the reliability of the organic EL panel varies greatly depending on the process step in which the aging treatment is performed, and through this study, the technology for improving the reliability of the organic EL panel has emerged.

Accordingly, an object of the present invention is to provide an aging method that can improve the reliability of an organic EL panel by performing an aging treatment at an initial stage of depositing a second electrode (cathode). There is this.

Another object of the present invention is to provide an aging method capable of suppressing the occurrence of shorts and leaks of organic EL devices due to the incorporation of foreign matters in the manufacture of organic EL devices.

A feature of the aging method of the organic EL device according to the present invention for achieving the above object is in the aging method of the device for emitting an organic layer having a light emitting layer by applying a voltage to at least one of the first electrode and the second electrode, In the initial step of forming the second electrode in a vacuum chamber, a reverse voltage or a reverse current is applied between the two electrodes to perform an aging process of removing a short portion that causes a leak current. .

Other objects, features and advantages of the present invention will become apparent from the following detailed description of embodiments with reference to the accompanying drawings.

A preferred embodiment of the aging method of the organic EL device according to the present invention will be described with reference to the accompanying drawings.

2 is a flowchart showing an aging method of an organic EL device according to the present invention.

As shown in FIG. 2, first, a substrate of a glass material is initially cleaned (S200), and then an ITO (indium tin oxide) transparent electrode and an auxiliary electrode are manufactured on the substrate (S210). Subsequently, an insulating film and a partition wall are fabricated on the auxiliary electrode (S220).

In this case, the first electrode, the auxiliary electrode, the insulating film, and the partition wall are manufactured by a photolithography process.

Subsequently, the entire surface is cleaned (S230) and surface treatment is performed (S240), and then a multilayer organic film (hole injection layer, hole transport layer, light emitting layer, electron transport layer) is formed on the surface treated surface (S250).

In the initial stage of forming aluminum, which is the second electrode, aging is performed simultaneously with the deposition of the second electrode (S260).

The aging process simultaneously applies a constant forward voltage or current or reverse voltage or current to the panel in order to suppress short-circuits or current leaks caused by adsorption on a substrate that is an external foreign material during the organic EL panel fabrication process. Or it is applied in the form of AC / DC / pulse respectively.

At this time, the size of the material (several nm ~ several tens um) and the composition (metal, insulator, carbon, etc.) is very variable, so the voltage applied to the very important variable in repairing (repair) the duvet attachment site (bad site). Therefore, if the voltage is too low, there may be a large number of defective areas that are not recovered. If the voltage is too high, the defective areas may be excessively destroyed to cause deterioration of the panel. Moreover, the effect, withstand voltage characteristic, etc. change according to which stage of a process is performed.

In general aging, as shown in FIG. 1, a method of applying a constant voltage or current in a semi-finished state in which encapsulation, which is a protective process after depositing organic material and a cathode on a substrate, is completed.

However, this conventional method is performed after the completion of the deposition, the device is completed, that is, after a leak source or defect inevitably generated during the process, so that the voltage or current to remove the defect is increased. It is easily damaged during the process. Therefore, deterioration or destruction of the device is caused, resulting in a drop in yield. Fortunately, even a temporarily healed device can be a potential source of failure that progresses slowly over time.

Therefore, the aging treatment of the present invention is to overcome such disadvantages, and does not perform the aging process after the second electrode deposition and encapsulation process is finished as in the prior art, as shown in reference numeral S260 of FIG. 2. It is carried out simultaneously.

In this case, the aging voltage or current application method may use a constant aging method for applying a constant voltage for a specific process time and a step aging method for gradually increasing the voltage from a low voltage as shown in FIG. 3.

Here, the low voltage is 0 to 5V, and the high voltage means a voltage (withstand voltage) at which the target voltage or the target organic EL panel is not degraded or destroyed by the high voltage. The withstand voltage varies depending on the constituent material, thickness, incorporation of impurities during deposition, etc., but usually has a range of 10 to 80V.

In particular, in the case of step aging, when the second electrode is formed, that is, when the second electrode is thin, a low voltage or current is applied, and as the second electrode becomes thicker, the absolute value of the voltage or current is gradually increased to form the second electrode. By applying the maximum voltage at termination, it is less likely to damage the device compared to constant aging.

Aging is performed by increasing the reverse voltage or current in steps at regular intervals, so that each defective part can recover from an appropriate voltage. Therefore, panel deterioration is more difficult than when aging is performed only at a specific high voltage or current. It can be significantly suppressed.

In addition, since the effect is more pronounced when a small amount of oxidizing gas such as oxygen is added during the aging treatment or the temperature is controlled, the concentration of the gas within the range that does not significantly affect the deposition rate or film quality during deposition in the vacuum chamber is increased. The temperature may be controlled within the range in which the organic matter is not affected, and the effect may be increased.

In order to realize such a method, a device for applying a voltage or a current between the first electrode and the second electrode of each panel must be installed in the vacuum chamber for forming the second electrode, which is very simple with current technology. to be.

Therefore, aging is applicable to aging between the first electrode and the second electrode, mutual aging between the first electrode and the second electrode, and AC / DC / pulse aging.

When the aging process is completed as described above, the encapsulation process is completed (S270) and assembled to manufacture the finished product (S280).

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the spirit of the present invention.

Therefore, the technical scope of the present invention should not be limited to the contents described in the embodiments, but should be defined by the claims.

The aging method of the organic EL device according to the present invention as described above has the following effects.

First, the aging treatment can be performed in the initial stage of depositing the cathode to improve the reliability of the organic EL panel.

Second, by performing the aging treatment in a specific process step, it is possible to effectively suppress the occurrence of shorts and leaks of the organic EL device due to the mixing of foreign matter in the manufacturing of the organic EL device.

Third, after the aging in the deposition chamber, by heating the temperature, or exposed to an appropriate amount of oxidizing gas or the like, or by applying a voltage under the temperature / atmosphere gas exposure, a more significant aging effect can be obtained.

1 is a flowchart showing an aging method of an organic EL device according to the prior art.

2 is a flowchart showing a method of aging an organic EL device according to the present invention.

3 is a view showing a method of applying an aging voltage or current applied in an aging method of an organic EL element according to the present invention.

Claims (5)

In the aging method of the device for emitting the organic layer having a light emitting layer by applying a voltage to at least one of the first electrode and the second electrode, The aging method of the organic EL element characterized in that an aging treatment is performed by applying a reverse voltage or a reverse current between two electrodes in an initial step of forming the second electrode in a vacuum chamber. The method of claim 1, The applied voltage or current always applies a constant voltage during the deposition of the second electrode. The method of claim 1, In the initial stage, the method of aging an organic EL device, characterized in that while applying a low voltage or current, gradually increasing the voltage or current as the deposition proceeds, and then applying the maximum voltage or current at the completion of the second electrode deposition. The method of claim 1, At least one of the concentration of the oxidizing gas in the vacuum chamber and the change of the temperature in the chamber within the range in which the organic matter is not affected during the aging treatment, characterized in that the aging method of the organic EL device. The method of claim 1, The applied voltage or current is within a range (0 to 80 V) in which the organic EL panel is not damaged.