JP2005276730A - Manufacturing method of organic el display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently carry out an aging treatment of an organic EL display substrate. <P>SOLUTION: A manufacturing process of the organic EL display device includes an organic EL element substrate forming process (S101), an aging process (S102), a sealing process (S103), a cutting process (S104), an optical film pasting process (S105), and a mounting process (S106). The aging process (S102) is carried out before the sealing process (S103). By this, a conventionally required substrate excision process to expose an aging terminal can be skipped. Furthermore, it can be made unnecessary to seal oxygen for aging in the organic EL display panel. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for manufacturing an organic EL (Electro Luminescence) display device, and particularly to an aging process in a manufacturing process of an organic EL display device.

  An organic EL display device using an organic EL light emitting element in a pixel portion has a wider viewing angle and a faster response speed than a liquid crystal display device, and is a next-generation display device due to a variety of light-emitting properties of organic substances. As expected. In general, an organic EL display device includes an organic EL element substrate on which a plurality of organic EL light emitting elements are formed, and a counter substrate for sealing the plurality of organic EL light emitting elements on the organic EL element substrate. An organic EL light emitting element includes a glass substrate, an anode formed on the glass substrate, a thin film organic compound (organic EL layer) laminated on the anode and including an organic light emitting layer, and an organic EL layer. A cathode formed so as to face the anode is provided.

  The organic EL light-emitting element is a current-driven display element that emits light when a current is supplied to an organic EL layer disposed between an anode and a cathode that are provided to face each other. Since the organic EL display device has characteristics similar to those of a semiconductor light emitting diode, it is sometimes called an organic LED. The organic EL light emitting element emits light by supplying a high potential to the anode of the organic EL light emitting element, applying a predetermined voltage between both electrodes and supplying a current to the organic EL layer. Conversely, when the cathode side is set at a high potential, almost no current flows through the organic EL layer, and the organic EL light emitting element does not emit light. When driving an organic EL light emitting element, a constant current driving method is generally used. That is, in order to obtain a predetermined light emission luminance, a drive circuit including a constant current circuit supplies a constant current to the organic EL light emitting element.

  In one of the well-known structures of organic EL display devices, a plurality of anode wirings connected to the anode or forming the anode itself are arranged in parallel on the glass substrate, and in a direction perpendicular to the anode wiring, A plurality of cathode wirings connected to the cathode or forming the cathode itself are arranged in parallel, and an organic EL layer is held between both the anode and the cathode. In an organic EL display device in which anode wiring and cathode wiring are arranged in a matrix, intersections between the anode wiring and the cathode wiring serve as pixels (organic light emitting elements), and the pixels are arranged in a matrix. In general, the cathode wiring is formed of metal, and the anode wiring is formed of a transparent conductive film such as ITO (indium / tin / oxide).

  When an organic EL display device in which anode wiring and cathode wiring are arranged in a matrix is driven by a simple matrix driving method, one of the anode wiring and the cathode wiring is used as a scanning electrode, and the other is used as a data electrode. . Then, a scan electrode driving circuit including a constant voltage circuit is connected to the scan electrode, and the scan electrode is driven at a constant voltage. Then, one of the scan electrodes is sequentially scanned every predetermined period to be in a selected state, and the other scan electrodes are in a non-selected state. In general, scanning is performed from a scanning electrode located at one end of a plurality of scanning electrodes arranged in parallel toward a scanning electrode located at the other end, and all the scanning electrodes are performed during a certain period. Are sequentially selected.

  A data electrode driving circuit having a constant current circuit at the output stage is connected to the data electrode. Then, a current corresponding to the display data of the row corresponding to the scan electrode in the selected state is supplied to each data electrode in synchronization with the scan. The current supplied from the constant current circuit to the data electrode flows through the organic EL layer located at the intersection of the scan electrode and the data electrode in the selected state to the scan electrode in the selected state. The pixel emits light in a period in which the scan electrode forming the pixel is in a selected state and current is supplied from the data electrode. Further, when the supply of current from the data electrode is stopped, the light emission is also stopped. When driving, the anode wiring of the organic EL display device may be a scanning electrode or a data electrode.

  When the organic EL light emitting element is driven with a constant current, the luminance decreases with time. The higher the initial luminance, the larger the rate of luminance decrease. For example, if the initial luminance is doubled, the time until the luminance is halved is approximately half. Furthermore, since the pixels (organic EL light emitting elements) that have been emitting light are darker, the phenomenon that the luminance varies depending on the pixels is caused. This phenomenon is called “burn-in”. If adjacent pixels have a luminance difference of about 3 to 5%, it is visually recognized that there is a luminance difference.

Due to technological development, the luminance half-life of the organic EL display element reaches several tens of thousands of hours at an initial luminance of about 100 cd / m ² , but burn-in occurs with a luminance drop of about 3 to 5%. It will occur in a hundred hours. This is a disadvantage of the organic EL display device relative to other flat panel display devices such as a liquid crystal display device.

  In many cases, the luminance of the organic EL light-emitting element greatly decreases in the initial stage due to energization, and then gradually decreases. In the case where the luminance is reduced as described above, when the organic EL light emitting element is driven for a while to reduce the luminance to a new initial state, the method of subsequent reduction becomes moderate. For this reason, before the organic EL display device is actually used, a process of driving the organic EL light emitting element for a while to lower the luminance is generally performed. This process is called an aging process.

  In the aging process, for example, the anode wirings of the organic EL element substrate are short-circuited by the lead wires, and the lead wires are connected to the voltage application device. Further, the cathode wirings are short-circuited by the lead wires, and the lead wires are connected to the voltage application device. And a voltage application apparatus applies a voltage pulse between the lead wire which connects an anode electric wiring person, and the lead wire which connects cathode wiring. Accordingly, a DC voltage is simultaneously supplied to each organic light emitting element on the substrate, and an aging process is executed.

  On the other hand, due to dust, dust or the like generated when forming a thin film of an electrode or an organic EL layer, a defective portion may occur in the electrode or the organic EL layer. In an organic EL light emitting device, since the organic EL layer between electrodes is extremely thin, even if this defective portion is minute, current is easily concentrated and the anode wiring and the cathode wiring are short-circuited, resulting in deterioration of device characteristics. There is a problem that leads to non-light emission. By using the above-described aging process, such a defective portion can be removed (see, for example, Patent Document 1). The short-circuit portion of the defective portion is destroyed by Joule heat generated during the aging process. Although the destroyed defective portion becomes a local non-light emitting portion, the defective portion is originally a minute one that cannot be visually recognized, and does not affect the display quality.

  FIG. 4 is a process diagram for explaining a manufacturing process of a conventional organic EL display device. First, in the organic EL element substrate forming step (S401), a plurality of organic EL element substrate portions are formed on a single glass substrate. Each organic EL element board | substrate part is cut | disconnected from a glass substrate, and is used as an organic EL element board | substrate of an organic EL display apparatus. In this step, a wiring group and an organic EL layer for each organic EL element substrate portion are formed on one glass substrate.

  Next, in the sealing step (S402), a counter substrate made of glass or the like is bonded to each organic EL element substrate portion with a sealing material. Since the organic EL layer of the organic EL element substrate portion is sealed by the counter substrate, it can be protected from external moisture and the like. In addition, one board | substrate with which the some counter substrate part was formed is adhere | attached on the board | substrate with which the several organic EL element board | substrate part was formed, and each organic EL element board | substrate part is sealed collectively.

  Next, in the aging terminal exposure step (S403), a part of the end surface of the substrate on which the plurality of counter substrate portions are formed is cut out, formed for aging treatment, and connected to each organic EL element substrate portion. The wiring terminals are exposed. Subsequently, in the aging process (S404), a voltage applying device for aging is connected to the exposed terminal, and aging is executed. When the aging process (S404) is finished, the glass substrate is cut and separated into a plurality of organic EL panels in the cutting step (S405). In the optical film attaching step (S406), an optical film such as a circularly polarizing plate is attached to each organic EL panel to prevent reflection. Finally, in the mounting step (S407), peripheral circuits such as a drive circuit are mounted.

JP 61-114493 A

  In the conventional manufacturing process of an organic EL display device, the aging process is performed after the sealing process. As described above, in the aging process, it is necessary to remove the short-circuit portion due to dust. Therefore, it is necessary to enclose a predetermined amount of oxygen in the sealed organic EL panel. In order to enclose oxygen in the organic EL panel, it is necessary to form a space of a predetermined size or more between the counter substrate and the organic EL element substrate. Or in order to perform an aging process after sealing, the process of cutting off the edge part of a glass substrate and exposing the electrode for aging connected with the voltage application apparatus for aging is required in a manufacturing process. This process is a cause of reducing the manufacturing efficiency of the organic EL display device.

  The present invention has been made against the background of the above circumstances, and is to efficiently perform an aging process on an organic EL element substrate.

  The method for manufacturing an organic EL display device according to the first aspect of the present invention includes a step of forming an organic light emitting layer on a substrate, a step of forming a wiring layer for transmitting a signal to the organic light emitting layer, and the organic light emitting In a state where the layer and the wiring layer are exposed, the organic light emitting layer is caused to emit light by supplying a signal to the wiring layer, and an aging process is performed. By performing the aging process in a state where the organic light emitting layer and the wiring layer are exposed, the manufacturing of the organic EL display device can be made efficient.

  It is preferable that the method further includes a step of fixing the counter substrate to the aged substrate and sealing the organic light emitting layer. By fixing the counter substrate, it is possible to effectively prevent moisture from entering from the outside and protect the organic light emitting layer from moisture. Alternatively, the aging treatment is preferably performed in an oxygen atmosphere. As a result, the short-circuited portion can be effectively destroyed by aging.

  According to a second aspect of the present invention, there is provided a method for manufacturing an organic EL display device comprising: forming a plurality of organic EL element substrate portions including an organic light emitting layer, an anode wiring, and a cathode wiring on a single substrate; Forming an anode common connection wiring connected to the anode wiring of the organic EL element substrate portion; forming a cathode common connection wiring connected to the cathode wiring of the plurality of organic EL element substrate portions; With the organic EL element substrate portion, the anode common connection wiring, and the cathode common connection wiring exposed, the plurality of organic EL element substrate portions are formed by supplying signals to the anode common connection wiring and the cathode common connection wiring. And emitting light and performing an aging process. By performing the aging process in a state where the organic light emitting layer and the wiring layer are exposed, the manufacturing of the organic EL display device can be made efficient. Furthermore, the production of the organic EL display device can be made more efficient by integrally forming a plurality of organic EL element substrate portions.

  The plurality of organic EL element substrate portions are fixed by fixing one substrate having a plurality of counter substrate portions corresponding to the plurality of organic EL element substrate portions to the substrate on which the plurality of organic EL element substrate portions are formed. Preferably, the method further includes a step of sealing and a step of separating each of the plurality of sealed organic EL element substrate portions. By fixing the counter substrate, it is possible to effectively prevent moisture from entering from the outside and protect the organic light emitting layer from moisture.

  ADVANTAGE OF THE INVENTION According to this invention, an aging process can be performed efficiently in the manufacturing process of an organic electroluminescence display.

  Hereinafter, embodiments to which the present invention can be applied will be described. The following description is to describe the embodiment of the present invention, and the present invention is not limited to the following embodiment. For clarity of explanation, the following description and drawings are omitted and simplified as appropriate. Moreover, those skilled in the art can easily change, add, and convert each element of the following embodiments within the scope of the present invention. In addition, in each drawing, the same code | symbol is attached | subjected to the same element and the duplication description is abbreviate | omitted as needed for clarification of description.

  FIG. 1 is a process flow diagram showing a manufacturing process of an organic EL (Electro Luminescence) display device according to this embodiment. As shown in FIG. 1, the manufacturing process of the organic EL display device of this embodiment includes an organic EL element substrate forming process (S101), an aging process (S102), a sealing process (S103), a cutting process (S104), and an optical film. A pasting step (S105) and a mounting step (S106) are included. Each of these processing steps is performed in the order described above. In this embodiment, in particular, the aging process (S102) is performed before the sealing process (S103). As a result, the substrate cutting step for exposing the terminal for aging, which has been conventionally required, can be omitted. Moreover, it is not necessary to seal oxygen for aging in the organic EL panel.

  Each processing step will be described. In the organic EL element substrate forming step (S101), a plurality of organic EL element substrate portions are formed by forming a wiring group and an organic EL layer on one glass substrate, thereby forming a multi-state organic EL element substrate. To do. FIG. 2 is a perspective view showing a schematic configuration of a multi-state organic EL element substrate (multi-organic EL element substrate) 200 formed by the organic EL element substrate forming step (S101).

  The multi-organic EL element substrate 200 includes a plurality of organic EL element substrate portions 202 on a single glass substrate 201. In a later manufacturing process, each organic EL element substrate unit 202 is separated from the substrate 201. FIG. 3 is a plan view showing a partial configuration of the multi-organic EL element substrate 200. In this embodiment, an organic EL display device in which anode wiring and cathode wiring are arranged in a matrix and driven by a simple matrix driving method will be described as an example.

  As shown in FIGS. 2 and 3, in the multi-organic EL element substrate 200, a plurality of organic EL element substrate portions 202 each including a display region 203 are formed on one glass substrate 201. The display area 203 includes a plurality of pixels (organic light emitting elements). Each organic light emitting element includes an organic material layer including an organic light emitting layer formed on a glass substrate 201, and an anode and a cathode formed so as to sandwich the organic material layer. Each organic EL element substrate unit 202 includes a glass substrate unit which is a part of the glass substrate 201 and an anode wiring 204 and a cathode wiring 205 which are formed so as to sandwich the organic light emitting layer. In this example, the anode wiring 204 and the cathode wiring 205 include the anode and the cathode of each organic EL light emitting element.

  Each anode wiring 204 in each organic EL element substrate section 202 is connected to a first common wiring 207 as a common wiring for anode by an anode connection wiring 206. Therefore, the same signal can be supplied from the first common wiring 207 to each anode wiring 204 in all organic EL display elements. Further, each cathode wiring 205 in each organic EL element substrate portion 202 is connected to a second common wiring 209 as a cathode common wiring by a cathode connection wiring 208.

  Therefore, the same signal can be supplied from the second common wiring 209 to each cathode wiring 205 in all the organic EL element substrate portions 202. By supplying signals via the common wirings 207 and 209, the organic EL element substrate portions 202 can be aged simultaneously. This point will be described later. In FIG. 1, the first common wiring 207 is indicated by a broken line, and the second common wiring 209 is indicated by a solid line.

  The organic EL element substrate forming step (S101) will be described in detail. First, an ITO film is formed on the glass substrate 201, and the ITO is etched to form the anode wiring 204, the anode connection wiring 206, and the cathode connection wiring 208. Next, a metal film is formed, and the formed metal film is etched to form a lead wiring, a first common wiring 207, and a second common wiring 209 in each organic EL element substrate portion 202. . On top of that, an insulating film is applied, and exposure development is performed to form an opening to be a light emitting portion of each pixel. Furthermore, an organic thin film as an organic EL layer is laminated thereon. As the organic thin film, a first hole transport layer, a second hole transport layer, a light emitting layer, and a cathode interface layer are sequentially formed. Finally, a scan electrode is formed of a metal such as aluminum as the cathode wiring 205 and connected to the cathode lead wiring.

  When the organic EL element substrate forming step (S101) is completed, each anode wiring 204 in the plurality of simple matrix type organic EL element substrate portions 202 formed on the glass substrate 201 is connected to the anode connection wiring 206 on the glass substrate 201. Are electrically connected to the first common wiring 207, and each cathode wiring 205 in the plurality of organic EL element substrate portions 202 is electrically connected to the second common wiring 209 via the cathode connection wiring 208 on the glass substrate 201. A multi-state organic EL element substrate 200 having a connected structure is formed.

  In the above example, the anode common wiring 207 and the cathode common wiring 209 are made of metal, and a transparent conductive film is used as the anode connection wiring 206 and the cathode connection wiring 208. The wiring 208 can be formed at the same time as the anode wiring 204 is formed. In addition, the anode common wiring 207 and the cathode common wiring 209 can be simultaneously formed before the organic EL layer is laminated.

  Next, in the aging process (S102), an aging process is performed on the multi-organic EL element substrate 200 formed in the organic EL element substrate forming process (S101). The aging process (S102) is performed before the sealing process (S103). Before the sealing, the EL light-emitting element including the organic light-emitting layer and each wiring on the substrate are in an exposed state. Therefore, the aging process is performed without cutting the edge of the substrate to expose the aging terminal. be able to.

  In the aging process executed in the aging step (S102), the first common wiring 207 and the second common wiring 209 are supplied to the anode wiring 204 and the cathode wiring 205 in order to supply signals for aging (energization processing). A voltage application device for aging is connected. In order to destroy and remove the defective portion in which the anode wiring 204 and the cathode wiring 205 are short-circuited by the aging process, the aging process is performed in an oxygen atmosphere of a predetermined concentration in the chamber. The aging treatment can be performed in a chamber that is vacuum degassed and introduced with a predetermined concentration of oxygen. Alternatively, it is also possible to introduce a gas such as nitrogen and oxygen and perform an aging treatment under reduced pressure or normal pressure.

  In the aging step (S102), the energization process is performed by setting the ambient temperature of the glass substrate 201 on which the plurality of organic EL element substrate portions 202 are formed to a room temperature or higher, preferably 80 ° C. or higher. By performing the energization process at a high temperature, a desired luminance can be reduced in a short time. The temperature at which the energization treatment is performed is preferably as high as possible within a range in which the organic EL light emitting element is not deteriorated. Even if the temperature is high, since the treatment is performed in a step prior to the optical film attaching step for attaching an optical film such as a circularly polarizing plate, the optical film is not adversely affected by heat.

Further, in order to reduce the desired luminance in a shorter time, the energization conditions are set so that the luminance of each pixel in the aging process is higher than the luminance when the rated display operation is performed as the organic EL display device. Set. For example, luminance level of the organic EL display device as long as 200 cd / ^{m 2,} is energized to emit light at 400 cd / ^{m 2.} By emitting light with a luminance twice as high as the luminance specification as the organic EL display device, the aging process is completed in about half the time compared to when aging is performed with the luminance specification as the organic EL display device.

Further, in the aging step (S102), static driving (1/1 duty) is performed in which the anode wiring 204 and the cathode wiring 205 are always energized. At this time, the current density does not need to be higher than the current density when operating as an organic EL display device as a final product. For example, the current density of the organic EL display device for multiplex driving at 1/50 duty is a 300 mA / cm ^2, if 12 mA / cm ² at static drive for aging, because the time average of the brightness is doubled It is.

  By the aging step (S102), the defective portion where the anode wiring 204 and the cathode wiring 205 are short-circuited can be destroyed and removed. Since the resistance values of the anode connection wiring 206 and the cathode connection wiring 208 are formed to predetermined values, the current flowing through the organic EL element is constant, and the defective portion can be removed with high accuracy.

  The multi-organic EL element substrate 200 that has been subjected to the aging treatment is a sealing process in which the organic EL element substrate unit 202 is isolated from the outside air with a counter substrate formed of glass or the like in order to protect the organic EL layer from moisture and the like ( S103). In the sealing step, in order to protect the organic EL layer formed on the glass substrate 201 in the organic EL element forming step (S101) from moisture, another glass substrate is disposed to face the glass substrate 201, and the gap Both glass substrates are bonded together by a peripheral sealing material as a material.

  On the other glass substrate, a counter substrate portion corresponding to each organic EL element substrate portion 202 is formed, and each organic EL element substrate portion 202 and each counter substrate portion are bonded together by a peripheral sealing material. Each counter substrate portion has a recess, and a desiccant is fixed thereto. Thereby, the organic EL element can be effectively protected from moisture. Dry nitrogen gas is sealed in the sealed space formed by the two glass substrates and the peripheral sealing material.

  When the sealing step (S103) is completed, a cutting step (S104) is performed in which the glass substrate 201 and the substrate bonded and fixed are cut and separated into a plurality of organic EL panels. The organic EL panel includes an organic EL element substrate on which a plurality of organic EL light emitting elements are formed, and a counter substrate bonded to the organic EL element substrate with a sealing material. In the cutting step, a cutting line (not shown) is set so as to surround the organic EL element substrate unit 202. For example, the cutting line is provided on the anode connection wiring 206 and the cathode connection wiring 208. Along the cutting line, the glass substrate 201 and the opposing substrate are cut to be separated into a plurality of organic EL panels. That is, each anode wiring 204 and each cathode wiring 205 are separated from the first common wiring 207 and the second common wiring 209. The cutting line may be on the anode wiring 204 and the cathode wiring 205.

  Next, in the optical film attaching step (S105), an optical film such as a polarizing plate or a 1 / 4λ plate is attached to the viewing side of the organic EL panel to prevent reflection. In the mounting step (S106), peripheral circuits such as a drive circuit are mounted on each organic EL panel to obtain an organic EL display device. Although it is preferable from the viewpoint of efficiency to manufacture a plurality of organic EL panels as described above, the present invention can of course be applied to a process of manufacturing organic EL panels one by one. In the above example, the organic EL element substrate (or its organic light emitting layer) is sealed by bonding the counter substrate, but it is also possible to seal by attaching a thin film.

It is process drawing for demonstrating an example of the manufacturing method of the organic electroluminescence display concerning this invention. It is a perspective view which shows schematic structure of the organic EL element substrate of the multi-state concerning this invention. It is a top view which shows the partial structure of the organic EL element substrate of the multi-state concerning this invention. It is process drawing for demonstrating the manufacturing method of the organic electroluminescence display in a prior art.

Explanation of symbols

200 element substrate, 201 glass substrate, 202 organic EL element substrate part,
203 display area, 204 anode wiring, 205 cathode wiring,
206 anode connection wiring, 207 anode common wiring, 208 cathode connection wiring,
209 Common wiring for cathode

Claims (5)

Forming an organic light emitting layer on a substrate;
Forming a wiring layer for transmitting a signal to the organic light emitting layer;
In a state where the organic light emitting layer and the wiring layer are exposed, the organic light emitting layer emits light by supplying a signal to the wiring layer, and an aging process is performed.
A method for manufacturing an organic EL display device having:   The method of manufacturing an organic EL display device according to claim 1, further comprising a step of fixing a counter substrate to the substrate subjected to the aging treatment and sealing the organic light emitting layer.   The method of manufacturing an organic EL display device according to claim 1, wherein the aging treatment is performed in an oxygen atmosphere. Forming a plurality of organic EL element substrate portions including an organic light emitting layer, an anode wiring and a cathode wiring on one substrate;
Forming anode common connection wiring connected to anode wiring of the plurality of organic EL element substrate parts;
Forming a cathode common connection wiring connected to the cathode wiring of the plurality of organic EL element substrate parts;
The plurality of organic EL elements by supplying a signal to the anode common connection wiring and the cathode common connection wiring in a state where the plurality of organic EL element substrate portions, the anode common connection wiring, and the cathode common connection wiring are exposed. Causing the substrate portion to emit light and aging treatment;
A method for manufacturing an organic EL display device having: The plurality of organic EL element substrate portions are fixed by fixing one substrate having a plurality of counter substrate portions corresponding to the plurality of organic EL element substrate portions to the substrate on which the plurality of organic EL element substrate portions are formed. Sealing the step;
Separating each of the sealed plurality of organic EL element substrate parts;
The method for producing an organic EL display device according to claim 4, further comprising:

Images