CN114078903A

CN114078903A - Electroluminescent device and display device

Info

Publication number: CN114078903A
Application number: CN202011642376.4A
Authority: CN
Inventors: 李松举; 孙贤文; 付东
Original assignee: Guangdong Juhua Printing Display Technology Co Ltd
Current assignee: Guangdong Juhua Printing Display Technology Co Ltd
Priority date: 2020-12-31
Filing date: 2020-12-31
Publication date: 2022-02-22
Anticipated expiration: 2040-12-31
Also published as: CN114078903B

Abstract

The invention discloses an electroluminescent device, which is characterized by comprising: a first encapsulation layer, the first encapsulation layer is arranged around the light-emitting area; a dam layer, the dam layer is arranged on one side of the first encapsulation layer, between the dam layers A groove is formed to expose the light-emitting area; a light-emitting function body, the light-emitting function body is arranged in the light-emitting area; a second encapsulation layer, the second encapsulation layer entirely covers the dam layer and the light-emitting function main body; a buffer layer, the buffer layer is arranged in the second encapsulation layer The side away from the light-emitting function main body is filled in the groove; the third packaging layer is disposed on the side of the buffer layer away from the second packaging layer. In the electroluminescent device, the buffer layer coated on the entire surface in the traditional technology is designed as discrete buffer layers, which can reduce the required thickness of the buffer layer. While reducing the thickness of the buffer layer, it can also ensure a flexible electroluminescent device. Overall bending resistance.

Description

Electroluminescent device and display device

Technical Field

The invention relates to the technical field of flexible device preparation, in particular to an electroluminescent device, a display device and application.

Background

A conventional flat panel display usually has two hard glass substrates and light emitting elements and other components located between the hard glass substrates, and can perform display only on a plane basis. Flexible displays typically replace the rigid glass substrate of conventional displays with a flexible substrate and a flexible encapsulation layer, and incorporate improvements in light-emitting elements and other components to enable flexible or foldable displays. The flexible display screen can bring more abundant service performance and provides more possibilities for the form of electronic equipment, so that the flexible display screen gradually becomes one of key projects of research of various manufacturers.

Conventional light-emitting elements are extremely sensitive to water and oxygen and are very easy to fail under the influence of water and oxygen, so that the encapsulation layer needs to have strong water and oxygen barrier capability, for example, 10^-6g/cm²Day. Moreover, the flexible display screen can face more frequent bending operations in practical application, which causes the packaging layer in the flexible display screen to face frequent bending. On one hand, in order to avoid fracture when the packaging layer is frequently bent as much as possible, the internal stress of the packaging layer is not easy to be too large; on the other hand, frequent bending may also cause defects in the encapsulation layer locally, resulting in a reduced water oxygen barrier capability.

In order to simultaneously take account of the water oxygen barrier capability and the bending resistance capability, an inorganic water oxygen barrier layer and an organic buffer layer are usually laminated alternately as an encapsulation layer in the conventional technology. The inorganic water oxygen barrier layer plays a role in efficiently blocking water and oxygen, the organic buffer layer plays a role in buffering deformation, and the whole internal stress of the packaging layer is reduced as far as possible. Limited by the precision of the preparation process, foreign matters or pinhole-shaped defects often appear in the packaging layer locally, the foreign matters or the defects can become the intrusion points of water and oxygen and gradually diffuse, and the deterioration area in the packaging layer continuously expands and finally develops into serious poor quality. Therefore, an organic buffer layer is required to cover the foreign matter and vacuum, providing a flat package surface for the inorganic water oxygen barrier layer. The thickness of the organic buffer layer generally needs to reach 10-20 μm to realize effective foreign matter coverage and meet the requirement of packaging yield. However, the thicker organic buffer layer also reduces the bend radius and bend tolerance of the flexible display. For the above reasons, it is often difficult to satisfy both the bending property and the barrier property of the flexible display screen.

Disclosure of Invention

In view of the above, the present invention provides an electroluminescent device with good barrier property and bending property, and accordingly, provides a display device.

According to one embodiment of the present invention, an electroluminescent device includes:

a first encapsulation layer disposed around the light emitting area;

the dam layers are arranged on one side of the first packaging layer, a groove is formed between the dam layers, and the light-emitting area is exposed;

the luminous functional body is arranged in the luminous area;

a second encapsulation layer entirely covering the bank layer and the light emitting functional body;

the buffer layer is arranged on one side, away from the light-emitting functional main body, of the second packaging layer and is filled in the groove;

and the third packaging layer is arranged on one side of the buffer layer, which is far away from the second packaging layer.

In one embodiment, the light emitting regions are multiple, the light emitting regions are distributed in multiple columns, and the dam layer is disposed on the first packaging layer between the light emitting regions in adjacent columns.

In one embodiment, the second encapsulation layer includes a plurality of sub-encapsulation layers stacked in a direction from the first encapsulation layer to the third encapsulation layer.

In one embodiment, the light emitting device further includes a substrate, the first encapsulation layer is disposed on the substrate, the dam layer is disposed on a side of the first encapsulation layer away from the substrate, and the light emitting functional body includes: the light-emitting device comprises a first electrode, a second electrode and a light-emitting functional layer, wherein the first electrode and the second electrode are oppositely arranged, and the light-emitting functional layer is arranged between the first electrode and the second electrode;

the substrate is provided with a thin film transistor and a first electric connection hole, a first conductor is filled in the first electric connection hole, one end of the first conductor is electrically connected to a drain electrode in the thin film transistor, and the other end of the first conductor is electrically connected to the first electrode.

In one embodiment, the substrate is provided with a common electrode and a second electric connection hole, the first packaging layer is provided with a third electric connection hole, the second electric connection hole is filled with a second electric conductor, and the third electric connection hole is filled with a third electric conductor; the second electrode is electrically connected to the common electrode through the second conductor and the third conductor.

In one embodiment, the thickness of the first packaging layer is 0.5-2 μm; and/or

The thickness of the dam layer is 1-6 mu m; and/or

The thickness of the second packaging layer is 0.5-2 μm.

In one embodiment, the height difference between the surface of the buffer layer on the side far away from the second packaging layer and the surface of the second packaging layer on the side far away from the dam layer is less than or equal to 0.3 μm.

In one embodiment, the materials of the first, second and third encapsulation layers are each independently selected from one or more of silicon nitride, silicon oxide, silicon oxynitride, aluminum oxide, titanium dioxide, hafnium dioxide, zinc oxide, magnesium oxide and zirconium oxide; and/or

The material of the dam layer is selected from polyimide; and/or

The material of the buffer layer is selected from one or more of silicon carbonitride, silicon oxycarbide, fluorinated silicon carbonitride, polydimethylsiloxane, parylene, polypropylene, polystyrene and polyimide.

A display device comprising an electroluminescent device as described in any one of the above embodiments.

In one embodiment, the display device is a cell phone, a television, a tablet, a display screen, a VR device, an AR device, a computer, or a vehicle mounted display.

Traditional whole face packaging layer relies on inorganic packaging layer and the alternative range upon form of organic packaging layer to have the performance of can buckling concurrently when keeping separation performance, the organic packaging layer releases the stress that inorganic packaging layer produced when buckling as far as possible, avoids the defect that the foreign matter leads to simultaneously.

The electroluminescent device in the above embodiment is different from the conventional full-surface package layer, and a discrete package structure is provided. Aiming at the structure of the dam layer, the discrete packaging structure corresponds to the luminous functional main body and the specific preparation process thereof, the structure of a plurality of packaging layers is designed to form the packaging type packaging of the luminous functional main body. Even if defects or cracks occur in the respective package layers in the portions where the buffer layer is not provided, the intrusion of water and oxygen can be effectively prevented. In addition, the buffer layer coated on the whole surface in the traditional technology is designed into the separated buffer layers, so that the thickness required by the buffer layer can be reduced, and the integral bending resistance of the flexible electroluminescent device can be ensured while the thickness of the buffer layer is reduced.

In addition, the buffer layer is changed into a discrete type and is filled in the recess between the dam layers, so that the smoothness of the flexible electroluminescent device can be ensured as far as possible, and the probability of the occurrence of the Mura problem is greatly reduced. Meanwhile, the height of the dam layer of the flexible electroluminescent device in the embodiment can be set to be higher, so that the bad defects such as bridging and the like generated in the printing process of the OLED material are avoided.

Drawings

Fig. 1 is a schematic cross-sectional view of a flexible electroluminescent device according to an embodiment;

fig. 2 is a schematic cross-sectional structure diagram of step S1 in the manufacturing process of the flexible electroluminescent device;

fig. 3 is a schematic cross-sectional structure diagram of step S2 in the manufacturing process of the flexible electroluminescent device;

fig. 4 is a schematic cross-sectional structure diagram of step S3 in the manufacturing process of the flexible electroluminescent device;

fig. 5 is a top view of step S3 in the fabrication process of the flexible electroluminescent device;

fig. 6 is a schematic cross-sectional structure diagram of step S4 in the manufacturing process of the flexible electroluminescent device;

fig. 7 is a schematic cross-sectional structure diagram of step S5 in the manufacturing process of the flexible electroluminescent device;

fig. 8 is a schematic cross-sectional structure diagram of step S6 in the manufacturing process of the flexible electroluminescent device;

fig. 9 is a schematic cross-sectional structure diagram of step S7 in the manufacturing process of the flexible electroluminescent device.

Wherein the reference numerals and meanings thereof are as follows:

110: a substrate; 111: a thin film transistor; 112: a first electrical conductor; 113: a common electrode; 114: a second electrical conductor; 120: a first encapsulation layer; 131: a first electrode; 132: a light-emitting functional layer; 133: a second electrode; 140: a dam layer; 150: a second encapsulation layer; 160: a buffer layer; 170: a third encapsulation layer; 180: and a third electrode.

Detailed Description

To facilitate an understanding of the invention, the invention will now be described more fully with reference to the accompanying drawings. Preferred embodiments of the present invention are shown in the drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items. "Multi", as used herein, means a combination of two or more items. Unless explicitly indicated or otherwise generally understood by those skilled in the art, the terms "ratio" or "concentration" and the like in this application should be considered as mass ratio or mass concentration.

The barrier layer in the conventional flexible light emitting device generally adopts a mode of alternately stacking organic/inorganic film layers, however, such barrier layer has difficulty in simultaneously considering the bending resistance and the barrier property of the flexible device. In order to improve the barrier property of the flexible light-emitting device while ensuring the bending resistance of the flexible light-emitting device as much as possible, one embodiment of the present invention provides a flexible electroluminescent device integrating a barrier layer, which at least includes:

a first encapsulation layer disposed around the light emitting region;

the luminous functional body is arranged in the luminous region;

In one specific example, the first encapsulation layer is disposed on the substrate, and the dam layer is disposed on a side of the first encapsulation layer away from the substrate.

Specifically, for ease of understanding and implementing this embodiment, referring to fig. 1, a flexible electroluminescent device 10 includes: a substrate 110, a first encapsulation layer 120, a light emitting functional body 130, a bank layer 140, a second encapsulation layer 150, a buffer layer 160, and a third encapsulation layer 170.

Specifically, a patterned first package layer 120 is disposed on the substrate 110, and the first package layer 120 defines a light-emitting region for disposing the light-emitting functional body 130. The light emitting functional body 130 is disposed on the substrate 110 in a light emitting region defined by the first packaging layer 120.

A dam layer 140 is disposed on a surface of the first encapsulation layer 120 on a side away from the substrate 110. A groove is formed between the dam layers 140 to expose the light emitting region.

The second encapsulation layer 150 entirely covers the bank layer 140 and the light emitting functional body 130. Specifically, the second encapsulation layer 150 covers the surface of the dam layer 140 that is not in contact with the first encapsulation layer 120, and extends to cover a side surface of the light-emitting functional body 130 away from the substrate 110. Further, the second encapsulation layer 150 covers the entire surface on the substrate 110 having the first encapsulation layer 120, the bank layer 140, and the light emitting functional body 130.

The light emitting functional body 130 is formed in a light emitting region defined by the first encapsulation layer 120, the dam layers 140 are disposed on the first encapsulation layer 120, and since a groove is formed between the dam layers 140, the second encapsulation layer 150 covering the light emitting functional body 130 is lower than the second encapsulation layer 150 covering the dam layers 140, and a groove is formed between the second encapsulation layers 150 covering the adjacent dam layers 140. Thus, a buffer layer 160 filling the groove is further provided on a surface of the second encapsulation layer 150 on a side away from the light-emitting functional body 130.

The third encapsulating layer 170 is disposed on a surface of the buffer layer 160 away from the second encapsulating layer 150. Further, in one specific example, when the buffer layer 160 is not disposed on a side surface of the second encapsulation layer 150 away from the dam layer 140, the third encapsulation layer 170 is also disposed on a side surface of the second encapsulation layer 150 away from the dam layer 140.

In one specific example, the light-emitting functional body 130 includes: the first electrode 131, the light-emitting functional layer 132, and the second electrode 133 are stacked in this order. The first electrode 131 is disposed on the substrate 110 and has a portion located in the light emitting region.

For example, the light emitting function layer 132 may include a liquid crystal display layer, and the first electrode 131 and the second electrode 133 are part of upper and lower electrodes for driving the liquid crystal to move. As another example, in one specific example, the light emitting function layer 132 may include a light emitting layer, the light emitting layer may be selected from an organic light emitting layer and a quantum dot light emitting layer, and the first electrode 131 and the second electrode 133 respectively function to inject holes and electrons.

In one specific example, the first electrode 131 is an anode for connecting to a positive electrode of an external power source.

In one specific example, the first electrode 131 may be selected from a film formed of one of a metal oxide conductive material, an organic conductive material, a conductive metal, and an alloy thereof, or a multi-layered film structure formed of a plurality of kinds. The metal oxide conductive material may be selected from ITO (indium tin oxide), IZO (indium zinc oxide), etc., the organic conductive material may be selected from PEDOT (3, 4-ethylenedioxythiophene monomer), and the conductive metal may be selected from aluminum, molybdenum, titanium, copper, silver, gold, etc.

Further, if the light emitting functional layer 132 is a top emission structure, i.e., emits light from the light emitting region, the first electrode 131 may be an ITO/Ag/ITO laminate structure in which the Ag plating layer serves as a light reflecting layer to reflect the light emitted from the light emitting functional layer 132 toward the light emitting region. The ITO has a function of matching hole injection in the light-emitting functional layer 132 and a work function of the transport layer, so that the holes are better injected into the light-emitting functional layer 132, which is beneficial to improving the overall efficiency of the light-emitting functional body.

In one specific example, the second electrode 133 is a cathode, which functions as an electrical connection similar to an anode, and electrons are injected into the light emitting function layer 132 through the cathode. The second electrode 133 may also be selected from a film formed of one or more of a metal oxide conductive material, an organic conductive material, a conductive metal, and an alloy thereof. The metal oxide conductive material may be selected from ITO (indium tin oxide), IZO (indium zinc oxide), etc., the organic conductive material may be selected from PEDOT (3, 4-ethylenedioxythiophene monomer), and the conductive metal may be selected from aluminum, molybdenum, titanium, copper, silver, gold, etc. Further, the second electrode 133 has high transparency, high conductivity, and relatively stable property in the range of the film thickness corresponding to the top emission structure of the light-emitting functional layer 132.

In one specific example, the light-emitting functional layer 132 further includes a hole functional layer disposed between the anode and the light-emitting layer, and the hole functional layer includes at least one of a hole injection layer and a hole transport layer.

In one specific example, the light-emitting functional layer 132 further includes an electron functional layer disposed between the cathode and the light-emitting layer, and the electron functional layer includes at least one of an electron injection layer and an electron transport layer.

In one specific example, the substrate 110 is further provided with a thin film transistor 111 and a first electrical connection hole, the first electrical connection hole is filled with a first conductor 112, one end of the first conductor 112 is electrically connected to the drain electrode in the thin film transistor 111, and the other end is electrically connected to the first electrode 131. The first electrode 131 is electrically connected to the drain of the thin film transistor 111 through the first conductor 112, and since the first conductor 112 is disposed inside the substrate 110, the first electrode 131 is not required to be connected to the thin film transistor through a lead wire connected to the outside, so that an additional lead path is not required to be formed in the first encapsulation layer 120, which not only saves the manufacturing process, but also can maintain the integrity of the first encapsulation layer 120.

In one specific example, the substrate 110 is further provided with a common electrode 113 and a second electrical connection hole, the first encapsulation layer 120 is provided with a third electrical connection hole, the second electrical connection hole is filled with a second electrical conductor 114, and the third electrical connection hole is filled with a third electrical conductor 121; the second electrode 133 is electrically connected to the common electrode 113 through the second conductor 114 and the third conductor 121. The common electrode 113 is also disposed inside the substrate 110, and the second electrode 133 is connected to the common electrode 113 through the second conductor 114 and the third conductor 121 inside the device, respectively, so that the integrity of the first encapsulation layer 120 and/or the second encapsulation layer 150 can be maintained without forming an additional wire path.

In one specific example, a third electrode 180 is disposed on the substrate 110, contacting the second conductor 114 and the third conductor 121, and spaced apart from the first electrode 131. The third electrode 180 may serve as a contact for the second conductor 114 and the third conductor 121, electrically communicating the second conductor 114 and the third conductor 121. Generally, the film formation area of the second electrode 133 is a whole-surface plating film of the display area, and a connection lead of the second electrode and the thin film transistor 111 array conductive circuit is disposed at the periphery of the display area, and is connected to the TFT circuit through a large-area cathode overlapping area (including a via hole and an exposed electrode structure), so as to finally form a loop to light the light emitting function layer 132. In this case, the first encapsulation layer 120 and/or the second encapsulation layer 150 need to be provided with a channel for the lead, which is equivalent to reserving a defect hole, so that the flexible electroluminescent device 10 of this embodiment cannot achieve a perfect encapsulation. The second conductor 114, the third conductor 121 and the common electrode 113 are all disposed inside the device, and by means of the second conductor 114 and the third conductor 121, the second electrode 133 can be directly connected to the common electrode 113 through the inside of the device, so that a hole communicated with the outside is effectively prevented from being formed inside the device.

In one specific example, the first encapsulation layer 120 is a water oxygen barrier layer, which functions as a water oxygen barrier. The material of the water-oxygen barrier layer should avoid using the material with too high hydrophobicity, because the first packaging layer 120 with too high hydrophobicity may prevent the ink from flowing in the light emitting region, so that the ink cannot flow uniformly in the light emitting region and thus cannot uniformly fill the material into the gap between the first packaging layers 120, resulting in the defect of non-uniform light emission. Specifically, the material of the water oxygen barrier layer may be selected from inorganic materials, and for example, may be one or more of silicon nitride, silicon oxide, silicon oxynitride, aluminum oxide, titanium dioxide, hafnium oxide, zinc oxide, magnesium oxide, and zirconium oxide. Preferably, the material of the water-oxygen barrier layer is selected from silicon oxynitride film layers. The number of oxygen atoms in the silicon oxynitride material can be adjusted, so that the hydrophilicity and hydrophobicity of the water-oxygen barrier layer can be adjusted. The method for preparing the water oxygen barrier layer can be plasma chemical vapor deposition, atomic layer deposition, ion beam deposition, magnetron sputtering deposition or the like. More preferably, the method of preparing the water oxygen barrier layer is plasma chemical vapor deposition.

In one specific example, the thickness of the first encapsulation layer 120 is 0.5 μm to 2 μm. Further, the thickness of the first encapsulation layer 120 should be thicker than the thickness of the light emitting functional layer 132 in the light emitting functional body 130.

The bank layer 140 can be provided as a discrete wall between different light-emitting functional bodies 130, and when each film layer of the light-emitting functional body 130 is prepared by a solution method such as ink-jet printing after the bank layer 140 is provided, the discharged ink can be confined in the light-emitting region and the light-emitting region by the higher bank layer 140.

In one specific example, a plurality of light emitting regions are disposed on the substrate 110, and the plurality of light emitting regions are distributed in a plurality of rows, and the dam layer 140 is disposed on the first encapsulation layer 120 between the light emitting regions in adjacent rows. The flexible electroluminescent device 10 includes a plurality of light-emitting functional bodies 130 arranged in a row. The bank layer 140 is provided only between the light emitting regions of adjacent columns. Further, the bank layer 140 between the light emitting regions of adjacent columns is a continuous bank layer 140, i.e., a line-type bank layer 140. The line-type bank layer 140 actually defines a row of the plurality of pixel light emitting units, and the ink-jet manner can be changed from ink-jet printing one by one to line-type printing, which can reduce the precision of the ink-jet apparatus in the line-type printing direction, reduce the precision requirement for the apparatus, and thus reduce the cost.

In one specific example, the material of the dam layer 140 may be selected from organic materials, such as polyimide. In actual preparation, coating and patterning of polyimide can be realized by adopting a method of gumming, exposing and developing.

On the other hand, in the conventional technology, the height of the dam layer is required to be as low as possible for the encapsulation layer to be disposed on the surface of the flexible device. This is because the higher the height, the more likely the encapsulation layer is to have a lower film thickness on the side walls and corners of the bank layer, and if the height is too high, peeling may directly occur, which causes significant defects and leads to package failure. However, in the flexible electroluminescent device 10 provided in this embodiment, since the separated encapsulation is adopted, the dam layer 140 can be set higher, so as to prevent the bridging phenomenon between the adjacent light-emitting functional bodies 130 caused by the overflow of ink during printing. This is because the buffer layer 160 is also provided in the flexible electroluminescent device 10 of the present embodiment. Specifically, after the preparation of the second encapsulation layer 150 is completed, the buffer layer 160 will substantially fill the light-emitting region between the dam layers 140, which can serve to buffer the stress of each encapsulation layer, cover the foreign material defects on the second encapsulation layer 150, and planarize the surface of the device, so that the third encapsulation layer 170 located at the top can be deposited on a relatively flat plane, thereby effectively improving the reliability of the package.

In one specific example, the thickness of the bank layer is 1 μm to 6 μm. Further, the thickness of the bank layer is 3 to 6 μm.

The second encapsulation layer 150 is a water oxygen barrier layer. Specifically, the material of the second encapsulation layer 150 may be selected from inorganic materials, for example, may be one or more of silicon nitride, silicon oxide, silicon oxynitride, aluminum oxide, titanium dioxide, hafnium oxide, zinc oxide, magnesium oxide, and zirconium oxide. Preferably, the material of the second encapsulation layer 150 is selected from a silicon oxynitride film layer. The method for preparing the water oxygen barrier layer can be plasma chemical vapor deposition, atomic layer deposition, ion beam deposition, magnetron sputtering deposition or the like. More preferably, the method of preparing the water oxygen barrier layer is plasma chemical vapor deposition.

The second encapsulation layer 150 mainly functions to insulate water and oxygen. Meanwhile, since the second barrier layer 150 covers the light emitting functional body 130, the thickness thereof should be generally set to be thinner to have a higher visible light transmittance. In one specific example, the thickness of the second encapsulation layer 150 is 0.5 μm to 2 μm, and further, the thickness of the second encapsulation layer 150 is 0.5 μm to 1 μm.

Since the second encapsulation layer 150 covers both the dam layer 140 and the light-emitting functional body 130, and there is a significant height fluctuation between the dam layer 140 and the light-emitting functional body 130, the water and oxygen barrier layer generally has a large internal stress, and it is not easy to completely cover the foreign matter on the encapsulation surface. The thin film is easy to be thin and broken at the tip of the foreign matter and the bottom of the step with the negative slope angle, and particularly when the packaging film is applied to a flexible display, the packaging film is easy to be broken and peeled or cracked at the place with the foreign matter, so that the packaging fails. The present embodiment further provides a buffer layer 160 and a third encapsulation layer 170.

The buffer layer 160 is selected from a soft, low internal stress film material to planarize the device surface as much as possible. The buffer layer 160 should also have high light transmittance. The material may be selected from inorganic materials with properties close to organic, for example: one or more of silicon carbonitride, silicon oxycarbide, fluorinated silicon oxycarbide, and fluorinated silicon carbonitride; alternatively, the material may be selected from polymeric materials such as: one or more of polydimethylsiloxane, parylene, polypropylene, polystyrene, and polyimide.

The buffer layer 160 mainly serves to buffer the stress of the upper and lower film layers, so that the device as a whole has better reliability and bending resistance. In addition, the buffer layer 160 can also cover impurity particles possibly adhered in the packaging process, so that the edges and corners of the particles are more rounded, a channel through which water and oxygen permeate is not easily formed, and the buffer layer has certain water and oxygen blocking performance. The preparation method may be selective coating technology such as inkjet printing, nano transfer printing, or plating technology, and preferably, the buffer layer 160 is prepared by inkjet printing. Ink is dropped at the space between the banks 170 using an inkjet printing method, and the thickness of the formed film layer is controlled to be equivalent to the height of the bank layer.

In one specific example, the buffer layer 160 may extend over the surface of the second encapsulation layer 150 on the dam layer 140.

In one specific example, the thickness of the buffer layer 160 should be set to match the thickness of the dam layer 140, and the surface of the buffer layer 160 on the side away from the second encapsulation layer 150 is flush with the surface of the second encapsulation layer 150 on the dam layer 140, or slightly higher than the surface of the second encapsulation layer 150 on the dam layer 140. Specifically, the height difference between the surface of the buffer layer 160 on the side away from the second encapsulation layer 150 and the surface of the second encapsulation layer 150 on the dam layer 140 is less than or equal to 0.3 μm.

The third encapsulation layer 170 is a water-oxygen barrier layer on the surface, and the material may be selected from inorganic materials, for example, one or more of silicon nitride, silicon oxide, silicon oxynitride, aluminum oxide, titanium dioxide, hafnium oxide, zinc oxide, magnesium oxide, and zirconium oxide. Preferably, the material of the third encapsulation layer 170 is selected from a silicon nitride film layer. The method for preparing the water oxygen barrier layer can be plasma chemical vapor deposition, atomic layer deposition, ion beam deposition, magnetron sputtering deposition or the like. More preferably, the method of preparing the water oxygen barrier layer is plasma chemical vapor deposition.

In one specific example, the height fluctuation of the third encapsulating layer 170 on the surface of the flexible electroluminescent device 10 is less than or equal to 10nm, and the height of the buffer layer 160 and/or the deposition amount of the third encapsulating layer 170 can be controlled to obtain the flexible electroluminescent device 10 with a flat surface as much as possible.

Traditional whole face packaging layer relies on inorganic packaging layer and the alternative range upon form of organic packaging layer to have the performance of can buckling concurrently when keeping separation performance, the organic packaging layer releases the stress that inorganic packaging layer produced when buckling as far as possible, avoids the defect that the foreign matter leads to simultaneously. The flexible electroluminescent device 10 in the above embodiment is different from the conventional full-surface package layer, and a discrete package structure is proposed. The discrete package structure is designed for the dam layer 140, the light-emitting functional body 130 and the specific manufacturing process thereof, and a multi-layer package structure is designed to form a package type package for the light-emitting functional body 130. Even if defects or cracks occur in each package layer in a portion where the buffer layer 160 is not provided, intrusion of water and oxygen can be effectively prevented. Moreover, the buffer layer coated on the whole surface in the conventional technology is designed into the separate buffer layers 160, so that the thickness required by the buffer layer 160 can be reduced while the buffer layer 160 is ensured to protect the light-emitting functional body 130 in the dam layer 140, and the bending resistance of the whole flexible electroluminescent device 10 can be increased. In addition, the buffer layer 160 is separated and filled in the recess between the dam layers 140, so that the flatness of the flexible electroluminescent device 10 can be ensured as much as possible, and the probability of occurrence of the Mura (Mura) problem can be greatly reduced. Meanwhile, the height of the bank layer 140 of the flexible electroluminescent device 10 in the above example can be set high, so as to avoid the undesirable defects such as bridging generated in the printing process of the OLED material.

Further, an embodiment of the present invention also provides a method for preparing the flexible electroluminescent device of the above embodiment, which includes the following steps:

preparing a patterned first packaging layer on a substrate, wherein a light-emitting area is arranged on the substrate, and the first packaging layer is arranged on the substrate and surrounds the light-emitting area;

preparing a patterned dam layer area outside the light-emitting area on one side of the first packaging layer far away from the substrate;

forming a light emitting functional body in a light emitting region on a substrate;

preparing a second encapsulation layer covering the dam layer and the light-emitting functional body;

preparing a buffer layer for filling the light-emitting area on the side, away from the light-emitting functional body, of the second packaging layer in the light-emitting area;

and preparing a third packaging layer on one side of the buffer layer far away from the second packaging layer and one side of the second packaging layer far away from the dam layer.

More specifically, referring to fig. 2, this embodiment is a method for manufacturing the flexible electroluminescent device 10 of the above embodiment, which includes the following steps.

In step S1, a substrate 110 is provided, the substrate 110 having a light emitting region thereon.

In one specific example, a thin film transistor 111 is provided in the substrate 110. As one example, the thin film transistor 111 includes a patterned semiconductor layer, a gate insulating layer, a gate conductive layer, an intermediate dielectric layer, a source conductive electrode, a drain conductive electrode, and a planarization layer.

The substrate 110 is provided with a first electrical contact hole filled with a first conductor 112, and the substrate 110 is further provided with a first electrode 131 in the light emitting region. One end of the first conductor 112 is electrically connected to the drain of the thin film transistor 111, and the other end is electrically connected to a first electrode 131 provided over the substrate 110.

In one specific example, the material of the first electrode 131 may be a composite film layer of ITO/Ag/ITO. The first electrode 131 may be prepared by a method such as magnetron sputtering, and after the first electrode 131 is prepared, patterning it so that it is partially or entirely disposed in the light emitting region is further included. The electrode material of the first conductive body 112 can be the same as the material of the first electrode 131, so that when the first electrode 131 is prepared by deposition, the material of the first electrode 131 enters the first electrical connection hole to form the first conductive body 112, and the preparation process is simplified.

Further, a third electrode 180 is disposed on the substrate 110 and spaced apart from the first electrode 131, a common electrode 113 and a second electrical connection hole are disposed in the substrate 110, a second conductive body 114 is filled in the second electrical connection hole, one end of the second conductive body 114 is connected to the common electrode 113, and the other end is connected to the third electrode 180.

In order to simplify the process, the third electrode 180 may be simultaneously prepared when the first electrode 131 is prepared, and the material of the third electrode 180 is the same as that of the first electrode 131. Further, the second conductive body 114 may be simultaneously prepared when the third electrode 180 is prepared, and the material of the second conductive body 114 is the same as that of the third electrode 180.

Specifically, after the deposition of the ITO/Ag/ITO laminate film is performed on the surface of the substrate 110, it is patterned to form the first electrode 131 and the third electrode 180.

In step S2, a patterned first encapsulation layer 120 is prepared on the substrate 110, the first encapsulation layer 120 being disposed around the light emitting region.

Specifically, a layer of material of the first sealing layer 120 in a film shape is formed on the substrate 110, and the first sealing layer 120 is pattern-processed so that the first sealing layer 120 is disposed around the light emitting region.

Further, the method for preparing the first encapsulation layer 120 is selected from evaporation, magnetron sputtering, plasma chemical vapor deposition, atomic layer deposition, or molecular layer deposition. Preferably, a plasma chemical vapor deposition method is used, and the material of the first encapsulation layer 120 is selected from silicon oxynitride, so that the amount of oxygen in the deposited silicon oxynitride film can be controlled by controlling the flow rate of each gas material during deposition, so that the hydrophilic type of the first encapsulation layer 120 can be adjusted. If the hydrophobicity of the first encapsulation layer 120 is too high, ink for printing each layer of the light-emitting functional body may not flow uniformly, so that the uniformity of the thin film of the light-emitting functional body is reduced, the performance of the device is affected, and even some pixels are free of OLED materials.

In one specific example, the formation area of the first encapsulation layer 120 is controlled when the first encapsulation layer 120 is prepared. The method for controlling the formation area of the first encapsulation layer 120 is to deposit a layer of material of the first encapsulation layer 120, and then perform patterning process on the first encapsulation layer 120, so that the light-emitting area exposes the surface of the first electrode 131 far away from the substrate 110. More specifically, a portion of the first electrode 131 is exposed to facilitate subsequent fabrication of other layers of material.

In one specific example, the patterning process of the first encapsulation layer 120 further includes the steps of forming a third electrical connection hole for filling the third electrical conductor 121 and exposing the third electrode 180.

In step S3, a patterned dam layer 140 is formed on the side of the first encapsulation layer 120 away from the board 110 and outside the light emitting region.

The material of the dam layer 140 may be selected from polyimide. The method of preparing the bank layer 140 is, for example: a film layer covering the entire surface of the device is formed by spin coating or slit coating, and then patterned by exposure, development, curing, and the like, thereby forming the bank layer 140.

In one specific example, the patterned dam layer 140 should expose an opening of the third electrical connection hole on the surface of the first encapsulation layer 120 away from the substrate 110, so that the third electrical conductor 121 fills and contacts the second electrode 133 disposed subsequently.

Referring to fig. 3, a top view of the semi-finished product prepared in the preparation step is shown. In one specific example, a plurality of light emitting regions are disposed on the substrate 110, and the plurality of light emitting regions are distributed in a plurality of rows, and the dam layer 140 is patterned such that the dam layer 140 is disposed on the first encapsulation layer 120 between the light emitting regions in adjacent rows. Further, the bank layer 140 between the light emitting regions of adjacent columns is in a continuous line shape; preferably, the bank layer 140 is linear.

The thickness of the linear bank layer 140 may be 1 to 6 μm, which is significantly high, and which can sufficiently confine ink in an ink jet printing process. Meanwhile, the bank layers 140 have a certain hydrophobic property, so that ink droplets entering the light emitting region later are confined between the bank layers 140, and the disadvantages of bridge connection and the like are avoided.

In step S4, the light-emitting functional body 130 is formed in the light-emitting region.

In one specific example, the light emitting functional body 130 includes a first electrode 131, a light emitting functional layer 132, and a second electrode 133, and since the first electrode 131 is formed on the substrate 110 in advance, the light emitting functional body 130 can be formed only by preparing the light emitting functional layer 132 and the second electrode 133 in this step.

Specifically, the step of forming the light emitting functional body 130 includes: preparing a light-emitting functional layer 132 on the side of the first electrode 131 far away from the substrate 110, preparing a second electrode 133 on the side of the light-emitting functional layer 132 far away from the first electrode 131, extending the material of the second electrode 133 and filling the third electrical connection hole with the material, so that the third electrical conductor 121 is formed.

The method for producing the luminescent functional layer 132 is ink-jet printing, and specifically, an ink containing a material of the luminescent functional layer 132 is sprayed in the luminescent region, and the solvent therein is removed to produce the luminescent functional layer 132. When the light emitting function layer 132 includes a plurality of layers, such as a light emitting layer, a hole transport layer, an electron transport layer, a hole injection layer, an electron injection layer, and the like, materials of the respective layers may be sequentially sprayed and a solvent thereof may be removed in multiple times or one time as the case may be, to prepare the light emitting function layer 132. In one specific example, the height of the light emitting function layer 132 after the solvent is removed is lower than the height of the first encapsulation layer 120.

After the light emitting functional layer 132 is prepared, the second electrode 133 may be formed at the light emitting region between the bank layers 140 by inkjet printing or selective atomic layer deposition and patterned deposition coating. It can be understood that the opening of the third electrical connection hole on the side of the first package layer 120 away from the substrate 110 is also located in the light-emitting region, so that the second electrode 133 can directly extend to the third electrical connection hole and fill the third electrical connection hole to form the third electrical conductor 121.

In one specific example, when the light emitting functional layer 132 is prepared by inkjet printing, the ink of the light emitting functional layer 132 may be simultaneously filled in the third electrical connection hole formed in advance, and therefore, after the light emitting functional layer 132 is prepared, a step of etching the light emitting functional layer 132 by using laser to empty the third electrical connection hole is further included.

In step S5, a second encapsulation layer 150 covering the dam layer 140 and the light emitting functional body 130 is prepared.

The method of preparing the second encapsulation layer 150 may be selected from magnetron sputtering, evaporation, plasma enhanced chemical vapor deposition, atomic layer deposition, or molecular layer deposition methods. When the second encapsulation layer 150 is prepared, only the material of the second encapsulation layer 150 needs to be deposited on the substrate 110 of the prepared light-emitting functional body 130.

Preferably, the silicon oxynitride film is prepared using a plasma enhanced chemical vapor deposition process.

It is understood that the second encapsulation layer 150 mainly functions as a water-oxygen barrier, and in addition, has an effect on the light emergent light and the preparation of subsequent layers thereon, and in order to improve the barrier capability as much as possible and obtain more beneficial technical effects, the second encapsulation layer 150 may include multiple sub-encapsulation layers. When the multi-layered sub-encapsulation layer is prepared, the material of the second encapsulation layer 150 is repeatedly deposited on the substrate on which the light-emitting functional body 130 is prepared.

Further, before and after the coating, foreign matters inevitably exist, and the packaging layer needs to be able to package the foreign matters as much as possible, so that water and oxygen do not invade the light-emitting functional body 130 through defects at the foreign matters, resulting in failure. However, the second encapsulation layer 150 generally does not cover and encapsulate the foreign material well, so that a buffer layer 160 is further provided.

In step S6, a buffer layer 160 filling the light-emitting region is prepared on the side of the second encapsulation layer 150 in the light-emitting region away from the light-emitting functional body 130.

Specifically, the material of the buffer layer 160 may be formed on the second encapsulation layer 150 in the light emitting region using an inkjet printing method to prepare the buffer layer 160. The amount of the material of the buffer layer 160 is controlled such that the thickness of the buffer layer 160 is 1 μm to 6 μm.

In one specific example, the prepared buffer layer 160 is flush with or higher than the second encapsulation layer 150 on the dam layer 140, and the height difference between the buffer layer 160 and the second encapsulation layer 150 on the dam layer 140 is less than or equal to 0.3 μm.

In the conventional full-surface packaging process, the thickness of the organic buffer layer is usually as high as 8 μm to 12 μm. In contrast, the buffer layer 160 in the flexible electroluminescent device 10 of the present embodiment is discrete, and the thickness thereof can be made thinner. The flexible electroluminescent device 10 can keep better bending performance while the thickness is reduced.

In step S7, a third encapsulation layer 170 is prepared on the side of the buffer layer 160 away from the second encapsulation layer 150 and the side of the second encapsulation layer 150 away from the dam layer 140.

The method of preparing the third encapsulation layer 170 may be selected from magnetron sputtering, evaporation, plasma enhanced chemical vapor deposition, atomic layer deposition, or molecular layer deposition methods. When the third encapsulating layer 170 is prepared, only the material of the third encapsulating layer 170 needs to be deposited on the substrate 110 on which the buffer layer 160 is prepared.

By the above manufacturing method, the flexible electroluminescent device 10 of the present embodiment can be manufactured.

Further, an embodiment of the present invention also provides a display device including the flexible electroluminescent device described in the above embodiment.

Specifically, the display device is a mobile phone, a television, a tablet computer, a display screen, a VR device, an AR device, a computer, or a vehicle-mounted display.

The technical features of the above embodiments can be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the above embodiments are not described, but should be considered as the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above examples are merely illustrative of one preferred embodiment of the present invention, which is described in more detail and detail, but should not be construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims

1. An electroluminescent device, characterized in that, comprising:

a first encapsulation layer, the first encapsulation layer is disposed around the light-emitting area of the electroluminescent device;

a dam layer, the dam layer is disposed on one side of the first encapsulation layer, and a groove is formed between the dam layers to expose the light-emitting region;

a light-emitting function main body, the light-emitting function main body is arranged in the light-emitting area;

a second encapsulation layer, the second encapsulation layer covers the dam layer and the light-emitting functional body as a whole;

a buffer layer, the buffer layer is disposed on a side of the second encapsulation layer away from the light-emitting functional body and is filled in the groove;

A third encapsulation layer, the third encapsulation layer is disposed on the side of the buffer layer away from the second encapsulation layer.

2 . The electroluminescent device according to claim 1 , wherein there are a plurality of the light-emitting regions, and the plurality of the light-emitting regions are distributed in a multi-column shape, and the dam layer is disposed on all the adjacent columns. 3 . on the first encapsulation layer between the light-emitting regions.

3 . The electroluminescent device according to claim 1 , wherein the second encapsulation layer comprises a plurality of sub-encapsulation layers stacked in a direction from the first encapsulation layer to the third encapsulation layer. 4 .

4 . The electroluminescent device according to claim 1 , further comprising a substrate, the first encapsulation layer is disposed on the substrate, and the dam layer is disposed on the first the side of the encapsulation layer away from the substrate, the light-emitting functional body comprises: a first electrode and a second electrode arranged oppositely, and a light-emitting functional layer arranged between the first electrode and the second electrode;

The substrate is provided with a thin film transistor and a first electrical contact hole, the first electrical contact hole is filled with a first conductor, and one end of the first conductor is electrically connected to the drain of the thin film transistor, The other end is electrically connected to the first electrode.

5 . The electroluminescent device according to claim 4 , wherein a common electrode and a second electrical contact hole are provided in the substrate, a third electrical contact hole is provided in the first encapsulation layer, and the The second electrical contact hole is filled with a second electrical conductor, and the third electrical contact hole is filled with a third electrical conductor; the second electrode is electrically connected to the second electrical conductor through the second electrical conductor and the third electrical conductor. the common electrode.

6 . The electroluminescent device according to claim 1 , wherein the first encapsulation layer has a thickness of 0.5 μm˜2 μm; and/or

The thickness of the dam layer is 1 μm˜6 μm; and/or

The thickness of the second encapsulation layer is 0.5 μm˜2 μm.

7 . The electroluminescent device according to claim 1 , wherein a surface of the buffer layer on a side away from the second encapsulation layer and a surface of the second encapsulation layer away from the bank layer. 8 . The height difference between the surfaces on one side is ≤ 0.3 μm.

8 . The electroluminescent device according to claim 1 , wherein the materials of the first encapsulation layer, the second encapsulation layer and the third encapsulation layer are independently selected from the group consisting of one or more of silicon nitride, silicon oxide, silicon oxynitride, aluminum oxide, titanium dioxide, hafnium dioxide, zinc oxide, magnesium oxide, and zirconium oxide; and/or

The material of the dam layer is selected from polyimide; and/or

The material of the buffer layer is selected from silicon carbonitride, silicon oxycarbide, fluorinated silicon oxycarbide, fluorinated carbon silicon nitride, polydimethylsiloxane, parylene, polypropylene, polystyrene and One or more of polyimides.

9. A display device, comprising the electroluminescent device according to any one of claims 1 to 8.

10 . The display device according to claim 9 , wherein the display device is a mobile phone, a television, a tablet computer, a display screen, a VR device, an AR device, a computer or a vehicle-mounted display. 11 .