KR102195384B1 - Passivation organic light emitting device and foldable display with the same - Google Patents

Abstract

The present invention relates to a passivation organic light emission device and a foldable display including the same and, more specifically, to a passivation organic light emission device capable of securing a flexible feature which can be applied to a foldable display as well as an anti-moisture feature which is no less than a proper level, through a simple process. According to the present invention, the passivation organic light emission device includes: a substrate; an ITO electrode layer formed to function as a positive electrode through a photography process after forming an ITO film on the front side of the substrate; an organic thin film layer made by forming organic thin films of an electron transfer layer, a light emission layer and a hole transfer layer made of an organic material; and a metal electrode layer formed to function as a negative electrode for transferring electrons to the organic thin film layer. The organic light emission device also includes a passivation thin film comprising a fluorine layer formed by being coated on the metal electrode layer of the organic light emission device through at least one solution process method selected from a group including a spin coating method, an inkjet printing method, a doctor blade method and a spray coating method and then hardening the same through a low-temperature thermal treatment of no more than 100°C.

Description

PASSIVATION ORGANIC LIGHT EMITTING DEVICE AND FOLDABLE DISPLAY WITH THE SAME}

The present invention relates to an organic light-emitting device, and in particular, to a passivation organic light-emitting device and a foldable display having the same to secure a moisture barrier property above an appropriate level and a flexible property applicable to a foldable display through a simple process. .

As the size of a portable display screen increases with the development of display technology, various methods for simultaneously satisfying portability and large screen display are being studied.

In order to satisfy the large screen display while maintaining portability, in recent years, foldable displays that can be folded or unfolded in order to maximize visibility without disconnecting the fold in the middle are rapidly emerging.

However, in the case of such a foldable display, the foldable substrate plays a very important role. If the folding and unfolding operation is repeatedly performed, micro cracks occur in the folds and increase, resulting in poor visibility, and eventually the function as a display. It has a problem of being badly processed due to deterioration.

According to the studies so far, in order to solve the above problem, a substrate laminated with a thin glass 10 and a polymer 20 as shown in FIG. 1 was used. However, when the number of times of folding and unfolding of the substrate of this configuration is more than 1,000 times, micro-cracks (MC) are generated in the folded portion of the thin film glass 10 as shown in FIG. 2, and the visibility of the substrate is extremely deteriorated.

In addition, in order to solve the problem of microcracks occurring in the thin-film glass, when the substrate is composed of only polymer films 20 such as PET and PC as shown in FIG. 3, it is improved than the substrate laminated with thin glass and polymer, but folded. When the number of unfolding was repeated thousands of times, a large crack (C1) also occurred in the folded portion of the polymer film as shown in FIG. 4.

The problem of such micro-cracks is that during the folding operation, a tensile force acts on the outer side to generate tensile stress that pulls the molecules in the substrate to both sides, and at the same time, a compressive force acts on the inner side to generate a compressive stress to push the molecules in the substrate to the center. However, it was caused by trying to stabilize the interior by breaking the connection between molecules and molecules in the substrate, not to withstand it due to material and structural limitations.

Meanwhile, in the case of an organic light emitting device used in a conventional display, glass encapsulation or metal encapsulation was applied as a protective film to improve the lifespan. This protective film acts as a physical barrier against atmospheric components such as moisture and oxygen in the atmosphere that can corrode the organic light emitting device.

Such encapsulation could be applied to a glass substrate without any problem, but there was a problem that it was difficult to apply to a wearable device or a foldable display in which the display itself can be folded and unfolded. Various researches are being conducted to replace this, but it was difficult to have the moisture barrier properties (10-6 g/m ² /day or less) required by the organic light emitting device protective film. In addition, there is a problem in that the process time required to form the protective layer is long or deposition is difficult.

Korean Patent Publication No. 2017-0122554 (2017.11.06)

Accordingly, the present invention has been proposed to solve the problems of the prior art, and an object of the present invention is a passivation capable of securing a moisture barrier property above an appropriate level and a flexible property applicable to foldable displays through a simple process. It is to provide an organic light emitting device and a foldable display having the same.

In order to achieve the above object, the passivation organic light emitting device according to the technical idea of the present invention comprises a substrate, an ITO electrode layer formed to act as an anode by a photography process after forming an ITO film on the entire surface of the substrate, and an organic material. For an organic light-emitting device comprising an organic thin film layer of a hole transport layer, a light emitting layer, and an electron transport layer formed on the ITO electrode layer, and a metal electrode layer formed to act as a cathode for transporting electrons to the organic thin film layer, a spin coating method, an inkjet printing method, A passivation thin film made of a fluorine layer formed by coating the metal electrode layer of the organic light emitting device by any one solution process method selected from the group including the doctor blade method and the spray coating method, and curing it by low temperature heat treatment at 100°C or less. It is characterized by its technical construction to further include.

Here, the fluorine layer is added in a dispersed state of inorganic nanoparticles made of any one of SiO ₂ , Al ₂ O ₃ , ZrO ₂ , TiO ₂ and Nano-diamond to improve surface hardness and gas barrier properties. It can be characterized by one.

In addition, in the passivation thin film, an inorganic material layer made of any one of Al ₂ O ₃ , ZnO ₂ , ZrO ₂ , TiO ₂ and HfO ₂ is additionally laminated on the fluorine layer, and the fluorine It can be characterized in that it has a multilayer structure in which an inorganic material layer is interposed between the fluorine layer and the fluorine layer by laminating the same fluorine layer again.

In addition, the inorganic material layer is brittle by placing the inorganic material layer at the neutral point of the tensile stress and compressive stress, which is the tension force generated inside due to the tensile force and compressive force acting during the folding and unfolding operation of the passivation organic light emitting device. It may be characterized in that it is designed to prevent damage.

In addition, the passivation thin film has a multilayer structure of at least five layers formed by alternately stacking the fluorine layer and an inorganic material layer made of any one of Al ₂ O ₃ , ZnO ₂ , ZrO ₂ , TiO ₂ and HfO ₂ . And, the fluorine layer may be positioned on the lowermost layer and the uppermost layer.

On the other hand, the foldable display according to the present invention includes a backplane including the above-described passivation organic light-emitting device and processed by wiring to implement an image output and a touch function; And a foldable substrate laminated on the front surface of the backplane, wherein the foldable substrate is positioned at a neutral point, which is an intermediate point between a portion where tensile force and compressive force act upon folding operation of the foldable display, and uses opposite forces of tensile force and compression force. It has a buffer layer that performs a buffer function that attenuates the internal tension caused by it, and the buffer layer is made of a plurality of glass fibers that have the same refractive index in the polymer and are aligned in a direction crossing the folding line of the foldable display. It is characterized by its technical configuration.

Here, the polymer of the buffer layer may be formed of a silicone-based polymer or an epoxy-based polymer.

In addition, the foldable substrate includes a hard coating layer bonded to the front surface of the buffer layer, a low surface energy coating layer made of a fluorine-based compound bonded to the front surface of the hard coating layer, and a resin bonded to the rear surface of the buffer layer to be laminated with the backplane. A layer is included, and the thickness of the hard coating layer and the low surface energy coating layer may be 20 um to 80 um and 20 nm to 80 nm, respectively.

The passivation organic light emitting device and the foldable display including the same according to the present invention can secure a moisture barrier property of an appropriate level or higher and a flexible property applicable to a foldable display through a simple process.

In addition, in the case of the foldable display of the present invention, a buffer layer made of polymer and glass fiber has a neutral point in order to alleviate the tension and impact generated inside due to the difference between the tensile force and the compressive force, which are opposing forces that simultaneously act during repeated folding and unfolding operations. By placing it in the buffer function, it is possible to minimize the occurrence of micro-cracks and maintain high-quality visibility for a long period of time.

1 to 4 are a series of reference diagrams for explaining a foldable substrate according to the prior art
5 is a schematic diagram of a passivation organic light emitting device according to an embodiment of the present invention
6 is a cross-sectional view for explaining the configuration of a passivation organic light emitting device according to an embodiment of the present invention
7A is a cross-sectional reference view for explaining a configuration in which a neutral point is applied to an inorganic material layer of a passivation organic light emitting device according to an embodiment of the present invention;
7B is a reference diagram for explaining an action and operation during a folding and unfolding operation in a state in which a neutral point is applied to an inorganic material layer of an organic light emitting device according to an embodiment of the present invention;
8 is a cross-sectional view of a passivation organic light emitting device according to a modified embodiment of the present invention
9 is a cross-sectional view of a passivation organic light emitting device according to another modified embodiment of the present invention
10 is a photograph of a comparative light emission experiment of an organic light emitting device according to whether or not a passivation thin film is applied by a fluorine layer
11 is a state diagram of a use of a foldable display according to an embodiment of the present invention
12 is a partial cross-sectional view for explaining a configuration of a foldable display according to an embodiment of the present invention
13 is a reference diagram for explaining an action and operation during a folding and unfolding operation of a foldable display according to an embodiment of the present invention
14 is a graph of experimental results for a foldable substrate excluding a backplane in a foldable display according to an embodiment of the present invention
15 is a reference diagram for explaining an experimental apparatus and an experiment method for a foldable substrate excluding a backplane in a foldable display according to an embodiment of the present invention

A passivation organic light emitting device according to embodiments of the present invention and a foldable display having the same will be described in detail with reference to the accompanying drawings. Since the present invention can apply various changes and have various forms, specific embodiments will be illustrated in the drawings and described in detail in the text. However, this is not intended to limit the present invention to a specific form of disclosure, and it should be understood that all changes, equivalents, and substitutes included in the spirit and scope of the present invention are included. In describing each drawing, similar reference numerals have been used for similar elements. In the accompanying drawings, dimensions of structures are shown to be enlarged than actual for clarity of the present invention, or reduced than actual to understand a schematic configuration.

Further, terms such as first and second may be used to describe various components, but the components should not be limited by the terms. These terms are used only for the purpose of distinguishing one component from another component. For example, without departing from the scope of the present invention, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element. Meanwhile, unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by a person of ordinary skill in the art to which the present invention belongs. Terms as defined in a commonly used dictionary should be interpreted as having a meaning consistent with the meaning in the context of the related technology, and should not be interpreted as an ideal or excessively formal meaning unless explicitly defined in this application. Does not.

<Example>

5 is a schematic diagram of a passivation organic light-emitting device according to an embodiment of the present invention, FIG. 6 is a cross-sectional view for explaining a configuration of a passivation organic light-emitting device according to an embodiment of the present invention, and FIG. 7A is It is a reference cross-sectional view for explaining a configuration in which a neutral point is applied to an inorganic material layer of an organic light-emitting device according to an embodiment of the present invention, and FIG. 7B is a folding and unfolding state in which a neutral point is applied to the inorganic material layer of the organic light-emitting device according to an embodiment of the present invention. It is a reference diagram for explaining the action and operation during operation.

As shown, the passivation organic light-emitting device according to the embodiment of the present invention secures a water barrier property above an appropriate level and flexible properties applicable to foldable displays by forming a passivation thin film on the surface of the organic light-emitting device (B1) through a simple process. I made it possible to do it.

The organic light-emitting device (B1) includes a substrate, an ITO electrode layer formed to act as an anode by a photography process after forming an ITO film on the entire surface of the substrate, and an organic thin film of a hole transport layer, a light emitting layer, and an electron transport layer made of an organic material. An organic thin film layer formed on the electrode layer, and a metal electrode layer formed on the organic thin film layer to act as a cathode for electron transport. Such an organic light emitting device (B1) corresponds to a generally known technology.

The passivation thin film is formed by sequentially stacking a fluorine layer 151, an inorganic material layer 152, and a fluorine layer 151. Looking at the configuration of such a passivation thin film, the fluorine layer 151 directly surrounds the surface of the metal electrode layer of the organic light-emitting device B1, and fluorine insects are formed and protected on the outermost surface exposed to the outside. In addition, a relatively brittle inorganic material layer 152 was interposed between the fluorine layer 151 and the fluorine layer 151.

The fluorine layer 151 is coated with a fluorine-based polymer solution by any one of a solution process method selected from the group including spin coating, inkjet printing, doctor blade method, and spray coating method, and then a low-temperature heat treatment furnace at 100°C or less. It is formed by hardening. (As a result of confirming through an actual experiment, it was possible to form a fluorine layer only by curing it on a hot-plate at 80°C for 1 minute.) Such a method is conventionally high temperature in excess of 100°C or phosphorus using UV curing. There is an advantage of minimizing the problem of performance degradation due to deterioration occurring in the encapsulation process.

When the fluorine layer 151 is formed in this way, there is an advantage that folding and unfolding operations are possible with flexible characteristics while securing the moisture barrier properties (10-6 g/m ² /day or less) required by the protective film of the organic light emitting device (B1). .

FIG. 10 is a sequence of photos of light emission by time of the organic light emitting device according to whether or not the fluorine layer 151 is applied to the actual organic light emitting device B1 in order to check the effect of the fluorine layer 151. The constant temperature and humidity conditions at this time were severe conditions, reaching a temperature of 60°C and a humidity of 90%, and the emission state of the organic light emitting device was measured for up to 60 hours. In the fluorine layer 151, it was confirmed that the growth of dark spots due to the influence of moisture and oxygen was significantly slowed compared to the organic light emitting device in which the fluorine layer 151 was not formed under severe conditions. This result shows that the passivation thin film including the flexible fluorine layer 151 has excellent moisture barrier properties, and thus a highly reliable passivation organic light emitting device can be implemented.

Further, to the fluorine-based polymer solution used to coat the fluorine layer 151, inorganic nanoparticles made of any one of SiO ₂ , Al ₂ O ₃ , ZrO ₂ , TiO ₂ and Nano-diamond are added in a dispersed state. It is desirable to do. Then, the surface hardness and gas barrier properties of the fluorine layer 151 are improved.

The inorganic material layer 152 is laminated on the fluorine layer 151 using any one of Al ₂ O ₃ , ZnO ₂ , ZrO ₂ , TiO ₂ and HfO ₂ as a material. In this way, when the fluorine layer 151 and the inorganic material layer 152 are combined to form a hybrid-type multi-layered structure, the moisture barrier properties are improved, as well as gas barrier properties and heat resistance properties, compared to a single fluorine layer 151 alone. It is possible to further increase the reliability by further improving.

However, in the case of the inorganic material layer 152, compared to the fluorine layer 151, the inorganic material is interposed between the fluorine layer 151 and the fluorine layer 151 because it has a brittle property that is easily damaged by folding and unfolding. Even if the layer 152 is damaged, the function can be maintained without being separated. Furthermore, as shown in FIGS. 7A and 7B, the inorganic material layer 152 is a neutral zone of tensile stress and compressive stress, which is a tension force generated inside due to the tensile force and compressive force acting during the folding and unfolding operation of the passivation organic light emitting device. By positioning it at the neutral point NP, it is possible to minimize damage caused by folding and unfolding. However, the configuration in which the inorganic material layer 152 is positioned at the neutral point NP in the passivation organic light emitting device is effective in preventing damage limited only during the folding and unfolding operation performed by the passivation organic light emitting device alone. In practice, when the passivation organic light-emitting device according to the present invention is applied to a product, the optimal design for the neutral point should be made in consideration of the thicknesses of other components. This will be described later in terms of a foldable display.

Meanwhile, FIG. 8 shows a modified embodiment in which a passivation thin film is provided with one fluorine layer 151. As described above, even with a configuration in which the passivation thin film is provided with one fluorine layer 151, it is possible to implement a highly reliable passivation organic light-emitting device with excellent moisture barrier properties as summarized in FIG. 10. Furthermore, by adding inorganic nanoparticles in a dispersed state to the fluorine layer 151, the surface hardness and gas barrier properties of the fluorine layer 151 may be improved.

In addition, FIG. 9 shows another modified embodiment in which the passivation thin film has a multilayer structure of at least five layers by alternately stacking the fluorine layer 151 and the inorganic material layer 152. At this time, the fluorine layer 151 is positioned in the lowermost layer and the uppermost layer, so that the reliability of moisture barrier is secured first. In the case of such a multilayer structure, there is a disadvantage that the same process must be additionally performed several times, but the thickness of each layer of the fluorine layer 151 and the inorganic material layer 152 is made thinner to block moisture without increasing the overall thickness of the passivation thin film. It is possible to secure higher reliability in terms of properties, gas barrier properties, strength properties, and durability. Even in such a modified embodiment, the surface hardness and gas barrier properties of the fluorine layer 151 may be further improved by adding inorganic nanoparticles to the fluorine layer 151 in a dispersed state.

Subsequently, a description will be given of a foldable display including the passivation organic light emitting device of the present invention described above and including a backplane that is wired to implement an image measuring force and a touch function.

11 is a state diagram of a use of a foldable display according to an embodiment of the present invention, FIG. 12 is a partial cross-sectional view illustrating a configuration of a foldable display according to an embodiment of the present invention, and FIG. 13 is This is a reference diagram for explaining the action and operation of the folding and unfolding of the foldable display.

The foldable display according to the embodiment of the present invention is capable of folding and unfolding operations, and includes the above-described passivation organic light emitting device of the present invention so that it can be applied to mobile devices such as the foldable smartphone shown in FIG. And a wire-treated backplane and foldable substrates 111 to 140 are laminated to implement a touch function.

Such a foldable display according to an embodiment of the present invention reduces the tension caused inside due to the difference between the compressive force and the tensile force, which is the opposite force that acts on the inside and outside during repetitive folding and unfolding operation. It is constructed to minimize occurrence and maintain high-quality visibility over a long period of time.

A foldable display according to an embodiment of the present invention includes the above-described passivation organic light emitting device of the present invention, including the backplane 150, which is wired to implement the image side force and touch function, as well as the buffer layer 110 and the hard coating layer 120. , A multi-layered foldable substrate including a low surface energy coating layer 130 and a resin layer 140. Among them, the buffer layer 110 is located at the neutral point (NP) based on the entire foldable display and performs a buffer function, thereby attenuating the tension generated inside due to the tension force and the compressive force, which are opposing forces acting during folding and unfolding operations. It plays the role of suppressing the occurrence of micro cracks. This configuration will be described in more detail for each component as follows.

The buffer layer 110 functions as a buffer to attenuate internal tension caused by the opposite force, which is the tensile force and the compressive force, while being located at the neutral point, which is an intermediate point between the tensile force and the compressive force, during the folding operation of the foldable display. . To this end, the buffer layer 110 has a unique configuration in which glass fibers 110b having the same refractive index are embedded in the polymer body 110a.

Here, the polymer body 110a forming the buffer layer 110 together with the glass fiber 110b is preferably made of a silicone-based polymer or an epoxy-based polymer, and in the case of a silicone-based polymer, heat resistance, electrical insulation, and chemical resistance , It is suitable for lamination with the backplane due to its excellent aging resistance, etc., and it is suitable for attenuating internal tension caused by tensile and compressive forces. Epoxy-based polymers are also laminated with the backplane and are suitable for attenuating internal tension caused by tensile and compressive forces.

The glass fibers 110b included in the buffer layer 110 must be implemented as a transparent buffer layer 110 with the same refractive index as the silicone polymer forming the body 110a of the buffer layer 110, and are aligned in a direction crossing the fold line. It is placed inside the buffer layer 110 in an aligned form. In this way, when a plurality of glass fibers 110b are included in an aligned state in the buffer layer 110, it is possible to effectively suppress the phenomenon that the bond between molecules is disconnected due to tensile stress, especially among the internal tensions during the folding and unfolding operation of the foldable display. do. Here, if a plurality of glass fibers (110b) are laid side by side in the direction crossing the folding line, it is desirable to have a sufficient effect even with a thin thickness, but it is not necessary, and even if the glass fibers (110b) are laid in a mixed form, tension It is helpful to suppress a phenomenon in which the intermolecular bonds of the buffer layer 110 are broken due to stress.

The buffer layer 110 occupies the lower part of the foldable substrate and is laminated with the backplane, but as shown in FIG. 13, the middle point of the portion where the tensile force (TF) and the compressive force (CF) are most strongly applied during the folding and unfolding operation of the foldable display. In order to be located at the in-neutral point NP, it is formed to have a thickness that can be secured to a region adjacent to the point, including a point that is exactly 1/2 of the total thickness.

The hard coating layer 120 is bonded to the entire surface of the buffer layer 110 and has a support force against external contact pressure including a user's finger contact, and has a high hardness of 5H to 6H or more. Such a hard coating layer 120 replaces the supporting force of the glass that is liable to be damaged by the internal tension force caused by the folding and unfolding operation, and contributes to supplementing the supporting force that is insufficient only by the buffer layer 110 against the external contact pressure.

The low surface energy coating layer 130 is provided on the entire surface of the hard coating layer 120 and is made of a fluorine-based compound material having a low coefficient of friction. It can be seen that the low surface energy coating layer 130 is sufficiently formed to have a thickness of about 20 to 80 nm, and is very thin compared to that of the hard coating layer 120 having a thickness of 20 to 80 μm. Such a low surface energy coating layer 130 serves to help minimize surface damage while helping the user's finger touch to occur smoothly. The low surface energy coating layer 130 and the hard coating layer 120 constitute a cover window and replace the existing glass layer.

The resin layer 140 serves to laminate the buffer layer 110 and the backplane 150. By including the resin layer 140, there is an advantage in that the thickness of the buffer layer 240 can be reduced and durability according to the folding and unfolding operation can be improved.

For reference, a brief explanation of the reason why micro cracks occur during repetitive folding and unfolding operations of the foldable display will be described below. That is, as can be seen in Fig. 13, a tensile force (TF) acts on the outer side of the folded portion during the folding operation to generate a tensile stress pulling the molecules in the substrate to both sides, and a compressive force (CF) acts on the inner portion of the folded portion. There is a compressive stress that tries to push my molecules to the center. In this way, when the opposite forces within the substrate, tensile stress and compressive stress occur at the same time, if the material and structural limitations cannot withstand it, it tries to stabilize the inside by breaking the connection between molecules and molecules inside the substrate, thereby causing micro-cracks externally. It happens. In order to solve this problem, if a material that is simply flexible to withstand the continuous folding motion cannot be secured sufficient support for the substrate, on the contrary, if a material that can secure the required support for the substrate is used, it is repeated as described above. During the adjacent folding and unfolding operation, there is a problem that the durability to withstand is lost. However, in the foldable display according to the embodiment of the present invention, when the tensile force (TF) and the compressive force (CF), which have opposite characteristics during the folding operation, act at the same time, at the neutral point (NP), which is the midpoint of the force. It is designed to offset the influence of these opposing forces without internal damage.

Moreover, since the passivation organic light emitting device that forms the basis of the backplane 150 has a passivation thin film composed of a fluorine layer 151 and an inorganic material layer 152 as described above, it has sufficient moisture barrier properties and is flexible. It is possible to secure a high level of durability against folding and unfolding operations across the foldable display, including not only the foldable substrate but also the backplane.

Subsequently, the results of self-experiment conducted in order to confirm the performance of the foldable substrate excluding the backplane in the foldable display according to the embodiment of the present invention will be described below.

14 is a graph showing experimental results for a foldable substrate excluding a backplane in a foldable display according to an embodiment of the present invention, and FIG. 15 is an experiment on a foldable substrate excluding a backplane in a foldable display according to an embodiment of the present invention It is a reference diagram for explaining the apparatus and the experimental method.

In this experiment, as shown in FIG. 15, the foldable substrate was repeatedly folded and unfolded over 20,000 times using a test apparatus. At this time, in order to provide the same environment as a mobile device such as a smartphone, an insertion member (RB) having a folding radius R was inserted and supported inside as a substitute for the main body of the mobile device.

Such experimental results are clearly shown in the graph of FIG. 14, and the foldable substrates included in the embodiment of the present invention correspond to M type, respectively. (For reference, the other types are foldable substrates of other types separately developed by the applicant in consideration of the neutral point, and are not disclosed in the specification of this application)

As a result of the experiment, it was found that in the case of the M type, in addition to the other types of foldable substrates developed, even 20,000 folding and unfolding operations continued to maintain normal visibility without generating microcracks. This can be said to be that the durability of the foldable substrate according to the prior art is dramatically improved compared to the fact that the visibility was extremely deteriorated even after 1,000 folding and unfolding operations.

Although the preferred embodiment of the present invention has been described above, the present invention can use various changes, modifications, and equivalents. It is clear that the present invention can be applied equally by appropriately modifying the above embodiments. Therefore, the above description does not limit the scope of the present invention determined by the limits of the following claims.

110: buffer layer 110a: polymer body
110b: glass fiber 120: hard coating layer
130: low surface energy coating layer 140: buffer layer
150: backplane 151: fluorine layer
152: inorganic material layer

Claims (10)

After the ITO film is formed on the entire surface of the substrate, an ITO electrode layer formed to act as an anode by a photography process, an organic thin film of a hole transport layer, a light emitting layer, and an electron transport layer made of an organic material is formed on the ITO electrode layer, the organic layer. For an organic light emitting device comprising a metal electrode layer formed to act as a cathode for transporting electrons in a thin film layer,
Formed by coating the metal electrode layer of the organic light emitting device by any one solution process method selected from the group including spin coating method, inkjet printing method, doctor blade method, and spray coating method, and cured by low temperature heat treatment at 100℃ or less Further comprising a passivation thin film made of one fluorine layer,
The passivation thin film further laminates an inorganic material layer made of any one of Al ₂ O ₃ , ZnO ₂ , ZrO ₂ , TiO ₂ and HfO ₂ on the fluorine layer, and the fluorine layer and the fluorine layer on the inorganic material layer The same fluorine layer is laminated again to have a multi-layered structure in which an inorganic material layer is interposed between the fluorine layer and the fluorine layer,
Prevent damage to the brittle inorganic material layer by placing the inorganic material layer at the neutral point of the tensile stress and compressive stress, which is a tension force generated internally due to the tensile force and compressive force acting during the folding and unfolding operation of the organic light emitting device. Passivation organic light-emitting device, characterized in that so as to. The method of claim 1,
In the fluorine layer, SiO ₂ , Al ₂ O ₃ , ZrO ₂ , TiO _2, and nano-diamonds are added in a dispersed state to improve surface hardness and gas barrier properties. Passivation organic light emitting device characterized by. delete delete The method of claim 1,
The passivation thin film has a multilayer structure of at least five layers formed by alternately stacking the fluorine layer and an inorganic material layer made of any one of Al ₂ O ₃ , ZnO ₂ , ZrO ₂ , TiO ₂ and HfO ₂ . , Passivation organic light emitting device, characterized in that the fluorine layer is located in the lowermost layer and the uppermost layer. As a foldable display,
After the ITO film is formed on the entire surface of the substrate, an ITO electrode layer formed to act as an anode by a photography process, an organic thin film of a hole transport layer, a light emitting layer, and an electron transport layer made of an organic material is formed on the ITO electrode layer, the organic layer. For the organic light-emitting device consisting of a metal electrode layer formed to act as a cathode for electron transport on the thin film layer, use any one solution process method selected from the group including spin coating method, inkjet printing method, doctor blade method, and spray coating method. It includes a passivation organic light-emitting device further comprising a passivation thin film made of a fluorine layer formed by coating on the metal electrode layer of the organic light-emitting device and curing by a low-temperature heat treatment of 100° C. or less, and wired for image output and touch function. Backplane; And
Includes; a foldable substrate laminated on the front surface of the backplane,
The foldable substrate,
It has a buffer layer that performs a buffer function that attenuates the internal tension caused by the opposite force, which is the tensile force and the compressive force, while being located at the neutral point, which is the middle point between the tensile force and the compressive force during the folding operation of the foldable display.
The buffer layer is a foldable display comprising a plurality of glass fibers that have the same refractive index in the polymer and are aligned in a direction crossing the fold line of the foldable display. The method of claim 6,
The polymer of the buffer layer is a foldable display, characterized in that provided with a silicone-based polymer or an epoxy-based polymer. The method of claim 6,
The foldable substrate includes a hard coating layer bonded to the entire surface of the buffer layer, a low surface energy coating layer made of a fluorine-based compound bonded to the front surface of the hard coating layer, and a resin layer bonded to the rear surface of the buffer layer to be laminated with the backplane. Included,
The thickness of the hard coating layer and the low surface energy coating layer is 20um ~ 80um, 20nm ~ 80nm, respectively, the foldable display. A foldable smartphone comprising the passivation organic light emitting device of any one of claims 1, 2 and 5. A foldable smartphone comprising the foldable display of claim 6.

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