JP7324676B2 - Method for manufacturing organic EL element - Google Patents

Description

The present invention relates to a method for manufacturing an organic electroluminescence device (hereinafter referred to as an organic EL device).

In recent years, in the field of small and medium-sized display devices used in electronic equipment and information equipment, there has been progress in miniaturization and weight reduction. Demand is increasing for organic EL elements (displays) with features such as low power consumption. Along with this, improvement in the quality and longevity of organic EL elements have become issues.

A light-emitting layer made of an organic material is laminated inside the organic EL element, and this light-emitting layer easily deteriorates due to moisture absorption in the atmosphere and reaction with oxygen, which causes quality deterioration. . In order to prevent moisture and oxygen from penetrating into the light-emitting layer, improve reliability, and extend the life of the light-emitting layer, a technique is known in which the surface of the light-emitting layer is coated with a curable protective resin for the purpose of protecting the light-emitting layer. ing. (For example, see Patent Documents 1 to 3)

Japanese Patent Laid-Open No. 8-162270 JP 2018-205344 JP 2019-139884

It is sufficient for the protective resin to cover at least the light-emitting layer of the organic EL element, but when the light-emitting layer is covered with the protective resin, the protective resin may adhere to areas other than the light-emitting layer. The protective resin adhering to areas other than the light-emitting layer must be removed as necessary, but since the protective resin is already hardened at the end of the manufacturing process, wet cleaning by immersion in a solvent, plasma, etc. It is very difficult to remove even with dry cleaning. In addition, if the protective resin is removed by applying pressure from the outside so as to scrape it off, the organic EL element may be damaged.

It is an object of the present invention to provide a method for manufacturing an organic EL device that can easily remove unnecessary protective resin adhering to regions other than the light-emitting layer. .

A method for manufacturing an organic EL device having a substrate on which a light-emitting layer is formed and a curable protective resin covering the light-emitting layer, the method comprising: a step of covering the light-emitting layer with the protective resin in an uncured state; and a cleaning step of removing the uncured protective resin adhering to a region outside the region where the light-emitting layer is formed after the coating step. method.

Even if the method for manufacturing an organic EL element has a curing step of curing the uncured protective resin covering the light-emitting layer after the coating step and before the washing step. good.

The method for manufacturing an organic EL element may further include a curing step of curing the uncured protective resin covering the light-emitting layer after the washing step.

In the curing step, a light-shielding mask that shields a region outside the light-emitting layer and does not shield the light-emitting layer is arranged, and light is irradiated through the light-shielding mask to cover the light-emitting layer. The method for manufacturing an organic EL element may include curing the protective resin in an uncured state.

In the cleaning step, by immersing the entire substrate in a solvent, the uncured protective resin adhering to a region outside the region where the light-emitting layer is formed is removed. It may be a manufacturing method.

Prior to the covering step, a protective substrate is attached to the substrate via a sealing member that has an opening and surrounds the light-emitting layer. By injecting the uncured protective resin, the light-emitting layer is covered with the uncured protective resin, and the uncured protective resin adhering to the outside of the sealing member is removed in the cleaning step. may be removed by washing.

Before the coating step, a wafer-shaped mother substrate on which a plurality of the light-emitting layers are formed is prepared as the substrate, and in the coating step, the plurality of the light-emitting layers formed on the mother substrate is not yet removed. Coating with the protective resin in a cured state, and bonding a wafer-shaped mother protective substrate to the mother substrate via the protective resin in an uncured state after the coating step and before the cleaning step. Subsequently, the uncured protective resin covering the plurality of light-emitting layers is cured, and in the cleaning step, the uncured protective resin adhering to the region outside the plurality of light-emitting layers is removed. The method for manufacturing an organic EL element may be such that the protective resin is removed by washing.

According to the present invention, it is possible to provide a method for manufacturing an organic EL device that can easily remove unnecessary protective resin adhering to regions other than the light-emitting layer.

Top view of organic EL element before protective resin injection (Example 1) A-A' cross-sectional view before injection of protective resin of organic EL element (Example 1) Top view of the organic EL element when protective resin is injected (Example 1) Top view of organic EL element after protective resin injection (Example 1) AA' cross-sectional view after injection of protective resin of organic EL element (Example 1) Top view of the organic EL element when the protective resin is cured (Example 1) A-A' cross-sectional view when the protective resin of the organic EL element is cured (Example 1) Cross-sectional view of the organic EL element during cleaning (Example 1) Top view of the organic EL element after cleaning (Example 1) AA' cross-sectional view after cleaning the organic EL element (Example 1) (a) Conceptual diagram showing a mother substrate bonding process, (b) Conceptual diagram showing a protective resin curing process, (c) Conceptual diagram showing a mother substrate cleaning process, (d) Mother substrate after cleaning. Conceptual diagram (Example 2)

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a top view of the organic EL element before protective resin is injected, and FIG. 2 is a cross-sectional view along A-A' before protective resin is injected into the organic EL element. The organic EL element 1 shown in FIGS. 1 and 2 includes a first substrate 5 (for example, a silicon substrate) on which a light-emitting layer 2 made of an organic material is formed, and a second substrate 6 for protecting the light-emitting layer 2 from the outside. (for example, a glass substrate) are laminated with their main surfaces facing each other via a frame-shaped peripheral seal 3 made of a resin adhesive, and then the peripheral seal 3 is cured. In the organic EL element 1 in this state, one side of the peripheral seal 3 is provided with an injection port 4 for injecting the protective resin 11 described later, and between the first substrate 5 and the second substrate 6, A gap 7 is formed into which the protective resin 11 is injected. A plurality of electrode pads 10 to which a voltage for driving the organic EL element 1 is applied are formed on one end portion of the first substrate 5 (offset portion with respect to the second substrate 6).

FIG. 3 is a top view of the organic EL element when a protective resin is injected. First, as shown in FIG. 3, an uncured protective resin 11 is injected into the organic EL element 1 shown in FIG. 1 using a dip-type vacuum injection method. In this method, the filling port 4 of the organic EL element 1 is immersed and brought into contact with the uncured protective resin 11 held in the tray 8 in a container evacuated to a vacuum state, and in this state, the inside of the container is pressurized to atmospheric pressure. , the protective resin 11 is injected into the gap 7 by capillary action and the pressure difference between the inside and outside of the organic EL element 1 . The protective resin 11 is a thermosetting resin or an ultraviolet curable resin made of epoxy resin or acrylate resin, and is an ultraviolet curable resin in this embodiment.

FIG. 4 is a top view of the organic EL element after the injection of the protective resin, and FIG. 5 is a cross-sectional view taken along the line A-A' after the injection of the protective resin into the organic EL element. As shown in FIG. 3, when the protective resin 11 is injected using the dip-type injection method, as shown in FIGS. 9 (see FIG. 3). The protective resin 11 that wets and spreads in the gap 9 outside the peripheral seal 3 wets and spreads to the offset portion of the first substrate 5 and may adhere to the electrode pads 10 formed in the offset portion. If the protective resin 11 adheres to the electrode pad 10, it will hinder electrical connection with the outside, which is a particular problem.

FIG. 6 is a top view when the protective resin of the organic EL element is cured, and FIG. 7 is a cross-sectional view along line A-A' when the protective resin of the organic EL element is cured. Next, as a step following FIG. 3, as shown in FIGS. 6 and 7, only the protective resin 11 injected inside the peripheral seal 3 is selectively cured. Specifically, a frame-shaped light-shielding mask 13 is placed on the upper surface of the second substrate 6 so as to cover only the area outside the peripheral seal 3 , and ultraviolet light is irradiated from above the light-shielding mask 13 to thereby remove the peripheral seal 3 . UV rays are applied only to the protective resin 11 injected into the region inside the , and only the protective resin 11 in that region is selectively cured. At this time, since the unnecessary protective resin 11 adhering to the outside of the peripheral seal 3 and the electrode pads 10 is not irradiated with the ultraviolet rays, the protective resin 11 in these regions remains in an uncured state. When the protective resin 11 is a thermosetting resin, for example, the protective resin 11 may be partially cured by locally applying heat rays (light) or a heater head.

8 is a cross-sectional view of the organic EL element during cleaning, FIG. 9 is a top view of the organic EL element after cleaning, and FIG. 10 is a cross-sectional view of the organic EL element taken along line A-A' after cleaning. Next, as a step following FIGS. 6 and 7, as shown in FIG. 8, the entire organic EL element 1 is immersed in a solvent 12 stored in a cleaning bath, and the outside of the peripheral seal 3 and the electrode pads are cleaned. The uncured protective resin 11 adhering to 10 is removed by dissolving and washing. At this time, the uncured protective resin 11 is removed more easily than the cured protective resin 11 . As the solvent 12, for example, ethyl acetate, butyl acetate, or the like is used in washing an acrylate resin. In this step, while the organic EL element 1 is immersed in the solvent 12, rocking cleaning, ultrasonic cleaning, heating cleaning, or the like may be performed. Alternatively, instead of immersing the entire organic EL element 1 in the solvent 12 , only the portion to which the unnecessary protective resin 11 adheres may be immersed in the solvent 12 . However, the unnecessary protective resin 11 can be reliably removed by immersing the entire organic EL element 1 in the solvent 12 .

By washing the organic EL element 1 in this manner, the organic EL element 1 shown in FIGS. 9 and 10 is obtained. In this organic EL element 1 , the protective resin 11 is not adhered to the outside of the peripheral seal 3 and the electrode pads 10 , and the protective resin 11 remains only inside the peripheral seal 3 . Although the uncured protective resin 11 injected into the injection port 4 is also removed by washing, the cured protective resin 11 is interposed between the injection port 4 and the light-emitting layer 2. Therefore, the light-emitting layer 2 is neither contaminated with the solvent 12 nor exposed to the outside.

In this embodiment, for example, the following modifications are possible. 8 without performing the step of curing the protective resin 11 shown in FIGS. 6 and 7 after the step of injecting the protective resin 11 shown in FIG. A cleaning process is performed, and finally a curing process of the protective resin 11 shown in FIGS. 6 and 7 is performed. Also by this modification, the unnecessary protective resin 11 adhering to the organic EL element 1 can be easily removed. In this modified example, when the organic EL element 1 is washed as shown in FIG. 8, the uncured protective resin 11 injected inside the peripheral seal 3 is excessively removed and the light emitting layer is removed. 2 may be exposed, but it can be dealt with by appropriately selecting the cleaning time and the type of solvent 12 . Further, in this modification, the step of curing the protective resin 11 (curing step using the light shielding mask 13) shown in FIGS. You may replace with the process of irradiating. In this case, the outside of the peripheral seal 3 and the electrode pad 10 are also irradiated with ultraviolet rays, but at this time, the unnecessary protective resin 11 adhering to these areas has already been removed by the previous cleaning process. is not a problem. Replacing the curing process in this way eliminates the need to partially cure the protective resin 11 using the light shielding mask 13, which leads to a corresponding reduction in man-hours.

FIG. 11 shows (a) a conceptual diagram showing a step of bonding the mother substrate, (b) a conceptual diagram showing a step of curing the protective resin, (c) a conceptual diagram showing the step of cleaning the mother substrate, and (d) after cleaning. 1 is a conceptual diagram showing a mother board; FIG. A manufacturing method shown in FIG. 11 is exemplified as a manufacturing method of an organic EL element according to another embodiment of the present invention. Specifically, it is as follows.

First, as shown in FIG. 11A, a protective resin 11 made of an uncured UV curable resin is applied to the entire main surface of a first substrate 5 made of a wafer-shaped mother substrate on which a plurality of light emitting layers 2 are formed. is dropped and uniformly applied, and then the main surface of the second substrate 6 made of a wafer-shaped mother substrate is attached to the main surface of the first substrate 5 on which the protective resin 11 is evenly applied. A laminated mother substrate 14 (see FIG. 11(b)) is prepared.

Next, as shown in FIG. 11B, a light-shielding mask 13 is placed on one main surface of the laminated mother substrate 14, and the light-emitting layer 2 is removed by irradiating the protective resin 11 with ultraviolet rays through the light-shielding mask 13. Only the covering protective resin 11 is selectively cured. The shape of the light shielding mask 13 used at this time is, for example, a shape in which only the region covering the light emitting layer 2 is opened and the other regions are shielded.

Next, as shown in FIG. 11(c), the entire laminated mother substrate 14 is immersed in a solvent 12 and washed to remove only the uncured protective resin 11. Next, as shown in FIG. At this time, the solvent 12 gradually penetrates between the first substrate 5 and the second substrate 6 from the outer periphery of the laminated mother substrate 14, and protects the uncured state interposed between the plurality of light emitting layers 2. The resin 11 is dissolved.

Next, as shown in FIG. 11(d), a plurality of organic EL elements 1 are produced by cutting the laminated mother substrate 14 into individual pieces.

According to this embodiment, it is possible to efficiently mass-produce organic EL elements 1 in which unnecessary protective resin 11 is not adhered to the outer periphery.

In Examples 1 and 2 described above, the second substrate 6 is not essential and may be omitted. Moreover, the organic EL element 1 is not limited to being used as a display, and may be used for other purposes.

The present invention is not limited to the above embodiments, and can take various other embodiments.

REFERENCE SIGNS LIST 1 organic EL element 2 light emitting layer 3 peripheral seal 4 inlet 5 first substrate 6 second substrate 7 gap 8 saucer 9 gap 10 electrode pad 11 protective resin 12 solvent 13 light shielding mask 14 laminated mother substrate

Claims (1)

A substrate on which a light-emitting layer is formed, a sealing member having an opening and surrounding the light-emitting layer, a translucent protective substrate bonded to the substrate via the sealing member, and covering the light-emitting layer A method for manufacturing an organic EL element having a photocurable protective resin,
a bonding step of bonding the protective substrate to the substrate via the sealing member;
a coating step of injecting the protective resin in an uncured state into the inside of the sealing member through the opening after the bonding step to cover the light-emitting layer with the protective resin in an uncured state; ,
After the covering step, a frame-shaped light-shielding mask having an opening is placed on the protective substrate, and light is irradiated toward the protective substrate through the opening of the light-shielding mask, thereby removing the seal member. a curing step of selectively curing only the uncured protective resin injected inside the
a cleaning step of removing the uncured protective resin adhering to the outside of the sealing member by cleaning after the curing step;
has
In the curing step, a part of the outer edge of the opening of the light-shielding mask overlaps the opening of the seal member in a plan view viewed from the light irradiation direction, and the opening of the light-shielding mask overlaps with the outer edge of the opening of the light-shielding mask. The other part of the outer edge overlaps with the sealing member in a plan view seen from the irradiation direction of the light.
A method for manufacturing an organic EL device, characterized by:

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