CN112420742A

CN112420742A - Flexible display device and preparation method

Info

Publication number: CN112420742A
Application number: CN202011224956.1A
Authority: CN
Inventors: 李林霜
Original assignee: Shenzhen China Star Optoelectronics Semiconductor Display Technology Co Ltd
Current assignee: Shenzhen China Star Optoelectronics Semiconductor Display Technology Co Ltd
Priority date: 2020-11-05
Filing date: 2020-11-05
Publication date: 2021-02-26
Anticipated expiration: 2040-11-05
Also published as: CN112420742B

Abstract

A flexible display device includes a display device body, a flexible substrate, a hydrogen-rich material layer, and a water-oxygen barrier layer disposed between the flexible substrate and the display device body, wherein a first surface of the flexible substrate is connected to the The hydrogen-rich material layer is connected, and the second surface opposite to the first surface of the flexible substrate is connected with the water-oxygen barrier layer; wherein, the hydrogen-rich material layer is used to strengthen the flexible substrate and the supporting device. Adhesion between rigid substrates of the hydrogen-rich material layer. The present application also provides a method for preparing the above-mentioned flexible display device.

Description

Flexible display device and preparation method

Technical Field

The application relates to the technical field of display, in particular to a flexible display device and a preparation method thereof.

Background

The flexible display device has the advantages of flexibility, curling, portability and the like. Therefore, flexible displays are becoming an important direction for the development of display devices. In addition, the transparent display can endow the flexible display device with wider application scenes and experience feelings. In flexible displays, especially flexible transparent displays, colorless transparent polyimide (CPI) is the preferred material for flexible substrates in flexible displays due to its combination of excellent heat resistance and high light transmittance.

At present, colorless transparent polyimide is mainly prepared by introducing fluorine-containing groups into polyimide molecular chain segments, but the colorless transparent polyimide has poor adhesion with a glass substrate due to the introduction of the fluorine-containing groups. Therefore, the flexible substrate and the rigid substrate made of colorless transparent polyimide (CPI) may be separated or even fall off during the manufacturing process. At present, flexible silane or siloxane segments are mainly introduced or doped into polyimide to improve the adhesion between a flexible substrate and a glass substrate. However, although the flexible silane, siloxane, or other segment introduced or doped into the colorless transparent polyimide (CPI) may improve the adhesion, it may reduce the heat resistance of the colorless transparent polyimide (CPI) and increase the CTE value thereof. Meanwhile, the colorless transparent polyimide (CPI) flexible substrate is damaged or even broken by using a laser lift-off (LLO) process technology.

In summary, since the flexible material is used as the substrate and has a weak carrying capacity, which affects the final process effect, the flexible substrate is generally attached to the rigid substrate, and after the process is completed, the flexible substrate and the rigid substrate are peeled off by a laser lift-off (LLO) process, but in the preparation process, the colorless transparent polyimide film and the substrate have poor adhesion, which may cause the risk of separation of the two substrates.

Disclosure of Invention

The application provides a flexible display device and a preparation method thereof, which are used for solving the problem that when a colorless transparent polyimide film is prepared on a rigid substrate in the prior art, the colorless transparent polyimide film is separated from the rigid substrate due to poor adhesive force of upper and lower base materials, so that the performance of the colorless transparent polyimide film is influenced.

In order to achieve the above purpose, the embodiment of the present application adopts the following technical solutions:

the embodiment of the application provides a flexible display device, which comprises a display device body, a flexible substrate, a hydrogen-rich material layer and a water-oxygen barrier layer arranged between the flexible substrate and the display device body, wherein a first surface of the flexible substrate is connected with the hydrogen-rich material layer, and a second surface opposite to the first surface of the flexible substrate is connected with the water-oxygen barrier layer;

the hydrogen-rich material layer is used for enhancing the adhesion between the flexible substrate and a rigid substrate for bearing the hydrogen-rich material layer.

In some embodiments, the hydrogen-rich material layer is an inorganic membrane layer, the hydrogen-rich material layer has a plurality of hydrogen-containing dangling bonds, and the hydrogen element content of the hydrogen-rich material layer is greater than 5 mol%.

In some embodiments, the material thickness of the hydrogen-rich material layer is less than 20nm, and the light transmittance of the hydrogen-rich material layer under irradiation of a laser with a wavelength of 308nm is less than 10%.

In some embodiments, the material of the flexible substrate is a colorless transparent polyimide.

In some embodiments, the free hydrogen atoms present in the hydrogen-rich material layer form hydrogen bonds with any one of oxygen atoms, nitrogen atoms, and fluorine atoms in the colorless transparent polyimide.

An embodiment of the present application further provides a method for manufacturing the flexible display device, where the method includes:

s10, forming a hydrogen-rich material layer on a rigid substrate;

s20, forming a flexible substrate on the hydrogen-rich material layer;

s30, sequentially forming a water oxygen barrier layer and a display device body on the flexible substrate;

s40, peeling the flexible substrate on which the hydrogen-rich material layer is formed from the rigid substrate, and removing the rigid substrate to obtain the flexible display device.

In some embodiments, in S10, the hydrogen-rich material layer is formed by an atomic deposition process or a chemical vapor deposition process.

In some embodiments, the S20 further includes:

s201, coating a colorless transparent polyamide acid solution on the hydrogen-rich material layer in a slit mode;

s202, the colorless transparent polyamic acid solution is subjected to a low-temperature solvent removal pre-curing process and a high-temperature main curing process to form the flexible substrate.

In some embodiments, in S202, the temperature of the pre-curing process is lower than 200 ℃, and the temperature of the main curing process is higher than 400 ℃.

In some embodiments, in S30, the flexible substrate is separated from the rigid substrate by a laser lift-off process in which the laser has a wavelength of 308 nm.

According to the flexible display device and the preparation method provided by the embodiment of the application, the hydrogen-rich material layer is introduced between the flexible substrate and the rigid substrate, and free hydrogen atoms in the hydrogen-rich material layer and oxygen atoms, nitrogen atoms or fluorine atoms in the flexible substrate form hydrogen bonds, so that the adhesion between the flexible substrate and the rigid substrate is enhanced by utilizing the chemical bond effect, the problem of separation of two base materials caused by poor adhesion is solved, meanwhile, the flexible substrate and the rigid substrate can be peeled without damage, and the problems of damage and even breakage of the flexible substrate in a laser peeling process engineering are solved.

Drawings

The following detailed description of embodiments of the present application is provided in conjunction with the appended drawings.

Fig. 1 is a schematic cross-sectional structural diagram of a flexible display device according to an embodiment of the present application.

Fig. 2 is a flowchart illustrating steps of a method for manufacturing a flexible display device according to an embodiment of the present disclosure.

Fig. 3A to 3D are schematic structural diagrams of a manufacturing method of a flexible display device according to an embodiment of the present disclosure.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. It is to be understood that the embodiments described are only a few embodiments of the present application and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

In the description of the present application, it is to be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the present application and for simplicity in description, and are not intended to indicate or imply that the referenced devices or elements must have a particular orientation, be constructed in a particular orientation, and be operated in a particular manner, and are not to be construed as limiting the present application. Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", may explicitly or implicitly include one or more of the described features. In the description of the present application, "a plurality" means two or more unless specifically limited otherwise.

In the description of the present application, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; may be mechanically connected, may be electrically connected or may be in communication with each other; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art as appropriate.

In this application, unless expressly stated or limited otherwise, the first feature "on" or "under" the second feature may comprise direct contact of the first and second features, or may comprise contact of the first and second features not directly but through another feature in between. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly under and obliquely below the second feature, or simply meaning that the first feature is at a lesser elevation than the second feature.

The following disclosure provides many different embodiments or examples for implementing different features of the application. In order to simplify the disclosure of the present application, specific example components and arrangements are described below. Of course, they are merely examples and are not intended to limit the present application. Moreover, the present application may repeat reference numerals and/or letters in the various examples, such repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed. In addition, examples of various specific processes and materials are provided herein, but one of ordinary skill in the art may recognize applications of other processes and/or use of other materials.

This application embodiment is to current when preparing colorless transparent polyimide film on the rigid substrate, because the adhesive force of upper and lower substrate is relatively poor, leads to colorless transparent polyimide film and rigid substrate separation to influence the technical problem of the performance of colorless transparent polyimide film, this defect can be solved to this embodiment.

Fig. 1 is a schematic cross-sectional structural diagram of a flexible display device according to an embodiment of the present disclosure. The flexible display device 10 comprises a display device body 14, a flexible substrate 12, a hydrogen-rich material layer 11 and a water-oxygen barrier layer 13 arranged between the flexible substrate 12 and the display device body 14, wherein a first surface of the flexible substrate 12 is connected with the hydrogen-rich material layer 11, and a second surface opposite to the first surface of the flexible substrate 12 is connected with the water-oxygen barrier layer 13;

wherein, the hydrogen-rich material layer 11 is used for enhancing the adhesion between the flexible substrate 12 and the rigid substrate for carrying the hydrogen-rich material layer 11.

Specifically, the material of the flexible substrate 12 is preferably colorless transparent polyimide (CPI), and the rigid substrate is a glass substrate, a metal substrate, or a quartz substrate.

Specifically, the display device body 14 includes a thin film transistor array, a display layer and an encapsulation layer, where the display layer may be an Organic Light Emitting Diode (OLED) Light Emitting layer, a liquid crystal display layer and a Micro-LED (Micro-Light Emitting Diode) display layer, and reference may be made to the prior art specifically, and details are not repeated here.

Specifically, the water and oxygen blocking layer 13 is an inorganic film layer for blocking water vapor from entering the display device body 14 from the outside, and the material of the water and oxygen blocking layer 13 is preferably silicon oxide or silicon nitride.

Specifically, the hydrogen-rich material layer 11 is an inorganic film layer, and the hydrogen-rich material layer 11 has a plurality of hydrogen-containing dangling bonds (generally, because the crystal lattice is suddenly terminated at the surface, each atom at the outermost layer of the surface has an unpaired electron, that is, an unsaturated bond, and the bond is called dangling bond, X-H);

further, the hydrogen-rich material layer 11 contains hydrogen in a molar percentage of more than 5%.

Further, the material thickness of the hydrogen-rich material layer 11 is less than 20nm, and the light transmittance of the hydrogen-rich material layer 11 under irradiation of laser light with a wavelength of 308nm is less than 10%.

Further, when the material of the flexible substrate 12 is a colorless transparent polyimide film (CPI), the free hydrogen atoms present in the hydrogen-rich material layer 11 form hydrogen bonds with any one of oxygen atoms, nitrogen atoms, and fluorine atoms in the colorless transparent polyimide, and the presence of the hydrogen bonds can significantly improve the adhesion between the flexible substrate 12 and the rigid substrate.

Preferably, the hydrogen-rich material layer 11 has excellent thermal stability and chemical resistance.

According to the technical scheme, the flexible display device provided by the embodiment of the application is characterized in that the flexible substrate 12 and the rigid substrate are provided with the hydrogen-rich material layer, the rigid substrate is peeled off, on one hand, the adhesion of the flexible substrate 12 to the rigid substrate can be obviously improved, and meanwhile, the flexible substrate 12 to the rigid substrate can be peeled off without damage.

Fig. 2 is a flowchart illustrating steps of a method for manufacturing a flexible display device according to an embodiment of the present disclosure. Wherein the method comprises the following steps:

s10, the hydrogen-rich material layer 22 is formed on a rigid substrate 21.

Specifically, the S10 further includes:

first, a rigid substrate 21 is provided, and the rigid substrate 21 is preferably a glass substrate, a metal substrate or a quartz substrate. Thereafter, a hydrogen rich material layer 22 is formed on the rigid substrate 21. Wherein the hydrogen-rich material layer 22 is formed by an atomic deposition process or a chemical vapor deposition process. Specifically, the hydrogen-rich material layer 22 is an inorganic membrane layer, and the hydrogen-rich material layer 22 has a plurality of hydrogen-containing dangling bonds (generally, because the crystal lattice is suddenly terminated at the surface, each atom at the outermost layer of the surface has an unpaired electron, namely, an unsaturated bond, and the bond is called dangling bond, X-H); the hydrogen-rich material layer 22 has a hydrogen content of greater than 5% by mole; the material thickness of the hydrogen-rich material layer 22 is less than 20nm, and the light transmittance of the hydrogen-rich material layer 22 under irradiation of laser light with a wavelength of 308nm is less than 10%, as shown in fig. 3A.

S20, forming a flexible substrate 23 on the hydrogen rich material layer 22.

Specifically, the S20 further includes:

first, a colorless transparent polyamic acid solution is slit-coated on the hydrogen-rich material layer 22. And then, forming the colorless transparent polyamide flexible substrate 23 through a low-temperature solvent removal pre-curing process and a high-temperature main curing process. Wherein the temperature of the low-temperature desolvation pre-curing process is lower than 200 ℃, and the temperature of the high-temperature main curing process is higher than 400 ℃. Preferably, the colorless transparent polyimide does not require additional adhesion enhancement treatment, and the colorless transparent polyimide with improved adhesion can also be compatible with the hydrogen-rich material layer 22. Further, the physical and chemical properties of the hydrogen-rich material layer 22 are not affected during the curing process of the colorless transparent polyimide, and the free hydrogen atoms present in the hydrogen-rich material layer 22 form hydrogen bonds with any one of oxygen atoms, nitrogen atoms and fluorine atoms in the flexible substrate 23, and the presence of the hydrogen bonds can significantly improve the adhesion between the flexible substrate 23 and the rigid substrate 21, as shown in fig. 3B.

S30, forming a water-oxygen barrier layer 24 and a display device body 25 on the flexible substrate 23 in this order.

Specifically, the S30 further includes:

firstly, preparing a water-oxygen barrier layer 24 on the flexible substrate 23; thereafter, a display device body 25 is formed on the water-oxygen barrier layer 24. The water and oxygen blocking layer 24 is an inorganic film layer for blocking water vapor from entering the display device body 25 from the outside, and the material of the water and oxygen blocking layer 24 is preferably silicon oxide or silicon nitride. The display device body 25 includes a thin film transistor array, a display layer and a packaging layer, where the display layer may be an OLED (Organic Light Emitting Diode) Light Emitting layer, a liquid crystal display layer and a Micro-LED (Micro-Light Emitting Diode) display layer, and reference may be made to the prior art specifically, and details are not repeated here. Further, the hydrogen rich material layer 22 does not have H during the manufacturing process of the display device body 25₂Overflow, as shown in fig. 3C.

S40, the flexible substrate 23 on which the hydrogen rich material layer 22 is formed is peeled off from the rigid substrate 21, and the rigid substrate 21 is removed to obtain the flexible display device.

Specifically, the S40 further includes:

and peeling the flexible substrate 23 on which the hydrogen-rich material layer 22 is formed from the rigid substrate 21 by a laser peeling process, and removing the rigid substrate 21 to finally obtain the flexible display device. Wherein. The laser wavelength in the laser stripping process is 308 nm; the hydrogen-rich material layer 22 will have a large amount of H after absorbing the laser energy in the laser lift-off process₂Overflow, as shown in fig. 3D.

To sum up, according to the flexible display device and the manufacturing method provided by the embodiment of the application, the hydrogen-rich material layer is introduced between the flexible substrate and the rigid substrate, and the free hydrogen atoms in the hydrogen-rich material layer and the oxygen atoms, the nitrogen atoms or the fluorine atoms in the flexible substrate form hydrogen bonds, so that the adhesion between the flexible substrate and the rigid substrate is enhanced by using the chemical bond effect, thereby improving the problem of separation of two base materials caused by poor adhesion, realizing nondestructive stripping of the flexible substrate and the rigid substrate, and solving the problems of damage and even fragment of the flexible substrate in the laser stripping process engineering.

In the foregoing embodiments, the descriptions of the respective embodiments have respective emphasis, and for parts that are not described in detail in a certain embodiment, reference may be made to related descriptions of other embodiments.

The flexible display device and the manufacturing method provided by the embodiment of the present application are described in detail above, and the principle and the embodiment of the present application are explained in the present application by applying specific examples, and the description of the above embodiments is only used to help understanding the technical scheme and the core idea of the present application; those of ordinary skill in the art will understand that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications or substitutions do not depart from the spirit and scope of the present disclosure as defined by the appended claims.

Claims

1. A flexible display device, characterized in that it comprises a display device body, a flexible substrate, a hydrogen-rich material layer, and a water-oxygen barrier layer disposed between the flexible substrate and the display device body, and the flexible substrate has a The first surface is connected with the hydrogen-rich material layer, and the second surface opposite to the first surface of the flexible substrate is connected with the water-oxygen barrier layer;

Wherein, the hydrogen-rich material layer is used to enhance the adhesion between the flexible substrate and the rigid substrate for carrying the hydrogen-rich material layer.

2 . The flexible display device according to claim 1 , wherein the hydrogen-rich material layer is an inorganic film layer, the hydrogen-rich material layer has a plurality of hydrogen-containing dangling bonds, and the hydrogen-rich material layer contains hydrogen The molar content of the element is greater than 5%.

3 . The flexible display device according to claim 2 , wherein the material thickness of the hydrogen-rich material layer is less than 20 nm, and the light transmittance of the hydrogen-rich material layer under irradiation of a laser with a wavelength of 308 nm is low. 4 . at 10%.

4 . The flexible display device according to claim 1 , wherein the material of the flexible substrate is colorless and transparent polyimide. 5 .

5 . The flexible display device according to claim 1 , wherein free hydrogen atoms existing in the hydrogen-rich material layer are the same as oxygen atoms, nitrogen atoms and fluorine atoms in the colorless transparent polyimide. 6 . either form hydrogen bonds.

6. A method for preparing a flexible display device according to claims 1-5, wherein the method comprises:

S10, forming a hydrogen-rich material layer on a rigid substrate;

S20, forming a flexible substrate on the hydrogen-rich material layer;

S30, forming a water-oxygen barrier layer and a display device body on the flexible substrate in sequence;

S40, peeling off the flexible substrate formed with the hydrogen-rich material layer from the rigid substrate, and removing the rigid substrate to obtain the flexible display device.

7 . The manufacturing method of the flexible display device according to claim 6 , wherein, in the S10 , the hydrogen-rich material layer is formed by an atomic deposition process or a chemical vapor deposition process. 8 .

8. The method for preparing a flexible display device according to claim 6, wherein the S20 further comprises:

S201, by slit-coating a colorless transparent polyamic acid solution on the hydrogen-rich material layer;

S202 , the flexible substrate is formed after the colorless transparent polyamic acid solution undergoes a low-temperature desolvation pre-curing process and a high-temperature main curing process.

9 . The manufacturing method of the flexible display device according to claim 8 , wherein in the S202 , the temperature of the pre-curing process is lower than 200° C., and the temperature of the main curing process is higher than 400° C. 9 .

10 . The manufacturing method of the flexible display device according to claim 6 , wherein in the step S30 , the flexible substrate is separated from the rigid substrate by a laser lift-off process, and the wavelength of the laser in the laser lift-off process is 10 . 308nm.