CN112406233B

CN112406233B - Protective film, flexible display module and flexible terminal

Info

Publication number: CN112406233B
Application number: CN202011307023.9A
Authority: CN
Inventors: 顾宇; 李骄阳
Original assignee: Kunshan New Flat Panel Display Technology Center Co Ltd
Current assignee: Kunshan New Flat Panel Display Technology Center Co Ltd
Priority date: 2020-11-20
Filing date: 2020-11-20
Publication date: 2023-07-21
Anticipated expiration: 2040-11-20
Also published as: CN112406233A

Abstract

The embodiment of the application provides a protection film, a flexible display module and a flexible terminal, wherein a flexible substrate is attached to the surface of a hardened film of a flexible cover plate, and an optical diamond film is arranged above the flexible substrate. Therefore, the flexible substrate has high impact strength and high folding endurance, and simultaneously combines the characteristics of high folding endurance and high hardness of the optical diamond film, so that the scratch resistance and the folding endurance of the surface of the flexible display module can be considered.

Description

Protective film, flexible display module and flexible terminal

Technical Field

The application relates to the technical field of flexible display, in particular to a protective film, a flexible display module and a flexible terminal.

Background

The flexible display module generally uses a Polyimide (PI) material as a protective cover plate, and the surface hardness of the protective cover plate is improved by Coating a Hard Coating (HC) on the surface of the protective cover plate. The inventors have found that polyimide materials are inherently soft and resistant to bending, but the hardened film is brittle, and the thicker the hardened film is, the higher the surface hardness is. Therefore, when the scratch resistance of the flexible display module is required to be improved, the thickness of the hardened film is inevitably increased, so that the bending resistance of the flexible display module is reduced, and the scratch resistance and the bending resistance of the flexible display module cannot be both considered.

Disclosure of Invention

Based on the defect of current design, this application provides a protection film, flexible display module assembly and flexible terminal, can compromise scratch resistance and bending resistance on flexible display module assembly surface.

According to a first aspect of the present application, there is provided a protective film for protecting a flexible cover plate, the protective film comprising:

a hardened film over the flexible cover plate;

a flexible substrate located over the hardened film; and

an optical diamond film over the flexible substrate.

Therefore, the flexible protective film is attached to the surface of the hardened film of the flexible cover plate, and the optical diamond film is arranged above the flexible protective film, so that the scratch resistance and the bending resistance of the surface of the flexible display module can be considered due to the fact that the flexible protective film is high in impact strength and high in bending resistance, and the characteristics of high bending resistance and high hardness of the optical diamond film are combined.

In one possible implementation manner of the second aspect, the protective film may further include:

and a first buffer layer positioned between the upper surface of the flexible substrate and the lower surface of the optical diamond film.

and the second buffer layer is positioned on the upper surface of the optical diamond film.

In a possible implementation manner of the second aspect, the method further includes:

a first buffer layer located between the upper surface of the flexible substrate and the lower surface of the optical diamond film; and

Thus, the stress distribution of the upper surface and the lower surface of the optical diamond film can be respectively regulated by arranging the first buffer layer between the upper surface of the flexible protective film and the lower surface of the optical diamond film and arranging the second buffer layer on the upper surface of the optical diamond film, so that the bending resistance of the protective film is further improved.

and the anti-fingerprint layer is positioned on the upper surface of the second buffer layer.

Therefore, the fingerprint can be effectively prevented from adhering to the surface in the using process of the flexible display module.

In a possible implementation manner of the second aspect, the flexible substrate is adhered to the hardened film on the surface of the flexible cover plate through a UV-reducing adhesive layer.

In one possible embodiment of the second aspect, the thickness of the optical diamond film is less than the thickness of the hardened film, preferably the thickness of the optical diamond film is 10nm or less.

In one possible embodiment of the second aspect, the flexible substrate comprises a coating layer and a substrate layer, the substrate layer being a substrate layer formed using polyethylene terephthalate, polyimide or cyclic olefin polymer.

According to a second aspect of the present application, there is provided a flexible display module, the flexible display module comprising:

a flexible display screen;

a flexible cover plate positioned on the flexible display screen; and

a protective film according to any one of the first aspect, the second aspect or any one of the possible embodiments of the second aspect located on the flexible cover plate;

the flexible cover plate comprises a curved cover plate and a folding cover plate.

According to a third aspect of the present application, there is provided a flexible terminal comprising the flexible display module set forth in the third aspect.

Based on any one of the aspects, the application attaches a flexible substrate on the surface of the hardened film of the flexible cover plate, and the optical diamond film is arranged above the flexible substrate. Due to the design, the flexible substrate is high in impact strength and high in folding endurance, and meanwhile, the scratch resistance and the folding endurance of the surface of the flexible display module can be considered by combining the characteristics of high folding endurance and high hardness of the optical diamond film.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the embodiments will be briefly described below, it being understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered limiting the scope, and that other related drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

Fig. 1 is a schematic structural diagram of a protective film according to an embodiment of the present disclosure applied to a flexible display module;

fig. 2 is a schematic structural diagram of a protective film according to another embodiment of the present application applied to a flexible display module;

fig. 3 is a schematic structural diagram of a protective film according to another embodiment of the present application applied to a flexible display module;

fig. 4 is a schematic structural diagram of a protective film according to another embodiment of the present disclosure applied to a flexible display module;

FIG. 5 shows a schematic structural diagram of a flexible terminal according to an embodiment of the present application;

fig. 6 shows a schematic structural diagram of a flexible terminal according to another embodiment of the present application.

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the embodiments of the present application more clear, the technical solutions of the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application, and it should be understood that the accompanying drawings in the present application are only for the purpose of illustration and description, and are not intended to limit the protection scope of the present application.

In this application, unless expressly stated or limited otherwise, a first feature "above" or "below" a second feature may include both the first and second features being in direct contact, and may also include the first and second features not being in direct contact but being in contact with each other by way of additional features therebetween. Moreover, a first feature being "above," "over" and "on" a second feature includes the first feature being directly above and obliquely above the second feature, or simply indicating that the first feature is higher in level than the second feature. The first feature being "under", "below" and "beneath" the second feature includes the first feature being directly under and obliquely below the second feature, or simply means that the first feature is less level than the second feature.

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. The materials or raw materials used in the present application may be obtained by purchasing them in a conventional manner, unless otherwise specified, and are used in a conventional manner in the art or according to the specification of the product. In addition, any methods and materials similar or equivalent to those described herein can be used in the methods of the present application. The preferred methods and materials described herein are illustrative only.

Referring to fig. 1, a schematic structure of a protective film 100 applied to a flexible display module 10 according to an embodiment of the present disclosure is shown.

In this embodiment, the flexible display module 10 may include the protective film 100 and the flexible display structure 200. Among them, the protective film 100 may include a hardened film 110, a flexible substrate 120, and an optical diamond film 130.

In one possible implementation, the flexible display structure 200 may include a flexible display screen 210 and a flexible cover 220. As shown in fig. 1, the flexible cover 220 is positioned over the flexible display screen 210, the hardened film 110 is positioned over the flexible cover 220, the flexible substrate 120 is positioned over the hardened film 110, and the optical diamond film 130 is positioned over the flexible substrate 120.

In this embodiment, the flexible display 210 may be any flexible display such as an LCD display, a PMOLED display, an AMOLED display, or a Micro-LED display.

In order to increase the surface hardness of the flexible cover 220, the scratch resistance of the flexible display module 100 may be improved by providing the hardening film 110 on the surface of the flexible cover 220 to increase the surface hardness. Meanwhile, since the hardened film 110 is a brittle material, the thicker the hardened film 110 is, the higher the surface hardness is, but the less bending resistance is to the flexible display module 100 as a whole.

The optical diamond (Diamon Like Carbon, DLC) film 130 is a film layer composed of carbon element, similar in nature to diamond, having a graphite structure sp2 bond and a diamond structure sp3 bond, thus having a graphite atom composition structure, having a hardness of more than 9H mohs hardness by itself, and having advantages of low friction factor, abrasion resistance, and good optical characteristics. Therefore, the hardness and the abrasion resistance of the flexible display module 10 with the optical diamond film 130 are greatly improved, so that the overall hardness of the flexible display module 10 is enhanced, and the probability of cracking of the flexible display module 10 after being impacted is reduced.

In addition, the optical diamond film 130 is typically disposed on a side facing away from the flexible cover plate 220 during use. When the flexible display module 10 falls, the optical diamond film 130 is impacted first, so as to buffer the flexible cover plate 220. And, even after the optical diamond film 130 is broken, the flexible cover plate 220 may be re-hardened by re-attaching or plating a layer of the optical diamond film 130 on the surface of the flexible cover plate 220.

Thus, by providing the flexible substrate 120 on the cured film 110 with the above-described structural design, the bending resistance of the protective film 100 can be improved because the flexible substrate 120 has high impact strength and high bending resistance. Meanwhile, the optical diamond film 130 has high bending resistance and high hardness, thereby allowing both scratch resistance and bending resistance of the surface of the protective film 100.

In one possible embodiment, still referring to FIG. 1, the flexible substrate 120 may be bonded to the hardened film 110 on the surface of the flexible cover plate 220 by a UV curable adhesive layer 115. Thus, the UV-adhesive layer 115 can not only provide bending sliding of the flexible cover 220, but also balance stress generated by bending. In addition, the UV-reduced adhesive layer 115 can be completely peeled off in a short time, and the change from adhesion to non-adhesion occurs, so that the flexible substrate 120 can be replaced by UV-reduced adhesion after abrasion.

In one possible embodiment, still referring to fig. 1, flexible cover 220 may be bonded to flexible display screen 210 by optical adhesive layer 215. The optical cement layer 215 includes solid optical cement (Optically Clear Adhesive, OCA), liquid Optical Cement (OCR), acryl cement (PSA), and the like. For example, the flexible cover 220 may be directly attached to the display surface side of the flexible display 210. For another example, a conductive layer may also be provided between the flexible cover 220 and the flexible display screen 210. In this embodiment, the fixing manner between the flexible cover 220 and the flexible display 210 may be the optical adhesive bonding manner, or may be other fixing manners, which is not limited in this embodiment. The flexible cover 220 can protect the flexible display 210 when attached to the surface of the flexible display 210, so as to avoid the flexible cover 220 from directly contacting with dust or other sharp objects in the environment.

The optical adhesive layer 215 may be a double-sided adhesive tape without a base material formed by adhering an upper layer and a lower layer of an optical acrylic adhesive to a release film, respectively, as an adhesive. Alternatively, the optical adhesive layer 215 may be a resistive optical adhesive or a capacitive optical adhesive, which is not limited in particular.

In one possible embodiment, the thickness of the optical diamond film 130 is less than the thickness of the hardened film 110. Preferably, in order to secure bending resistance of the optical diamond film 130 and improve optical transmittance, the thickness of the optical diamond film 130 may be 10nm or less.

In one possible embodiment, referring further to fig. 2, the flexible display module 100 may further include a first buffer layer 125, where the first buffer layer 125 is disposed between the upper surface of the flexible substrate 120 and the lower surface of the optical diamond film 130.

The first buffer layer 125 may be made of any material having a buffer function, for example, but not limited to, siNx, siOx, and the like. Thus, by providing the first buffer layer 125, the stress distribution of the lower surface of the optical diamond film 130 can be adjusted, reducing the risk of bending cracks. For example, when the first buffer layer 125 is made of SiOx material, it is known that the optical diamond film 130 is an amorphous state of carbon based on the above description. Therefore, when the first buffer layer 125 is a SiOx material film, the outermost electrons of the carbon and the silicon have the same number, but the number of electrons is different, and the two layers have similar atomic morphology, so that the first buffer layer 125 can be better combined with the optical diamond film 130, and the stress distribution on the lower surface of the optical diamond film 130 can be adjusted.

In a further possible embodiment, referring to fig. 3, the protective film 100 may further include a second buffer layer 140, and the second buffer layer 140 may be disposed on the upper surface of the optical diamond film 130.

The second buffer layer 140 may be made of any material having a buffer function, for example, but not limited to, siNx, siOx, and the like. In this way, by providing the second buffer layer 140, the stress distribution of the upper surface of the optical diamond film 130 can be adjusted, reducing the risk of bending cracks. For example, when the second buffer layer 140 is made of SiOx material, the second buffer layer 140 may be better combined with the optical diamond film 130 based on the principle described above, and the stress distribution of the upper surface of the optical diamond film 130 may be adjusted.

It should be noted that, in some possible embodiments, the above first buffer layer 125 and the second buffer layer 140 may be simultaneously provided in actual design, for example, as shown in fig. 3. Alternatively, only one of the above first buffer layer 125 and second buffer layer 140 may be provided. For example, the first buffer layer 125 may be provided only between the upper surface of the flexible substrate 120 and the lower surface of the optical diamond film 130, or the second buffer layer 140 may be provided only on the upper surface of the optical diamond film 130.

In one embodiment, as shown in fig. 3, when the above first buffer layer 125 and the second buffer layer 140 are simultaneously disposed, stress distribution of the upper surface and the lower surface of the optical diamond film 130 may be respectively adjusted, thereby further improving the bending resistance of the protective film 100.

In one possible embodiment, referring further to fig. 4, the flexible display module 100 may further include an anti-fingerprint layer 150 on the upper surface of the second buffer layer 140, so that fingerprints can be effectively prevented from adhering to the surface during use of the flexible display module 100.

It should be noted that, in practical design, the anti-fingerprint layer 150 may be disposed on the outermost layer of the flexible display module 100. Based on this, in some possible embodiments, when the flexible display module 100 is not provided with the second buffer layer 140, the anti-fingerprint layer 150 may also be directly disposed on the upper surface of the aforementioned optical diamond film 130.

In one possible embodiment, the substrate layer of the flexible substrate 120 may be formed of polyethylene terephthalate, polyimide, or cyclic olefin polymer, or the like. In some possible examples, the substrate layer is formed by coating, lamination, or the like.

Referring to fig. 5-6, the embodiment of the present application further provides a flexible terminal 1, which includes the flexible display module 10 described in the above embodiment, based on the same inventive concept. The flexible terminal 1 may be, but is not limited to, a cell phone, a tablet computer, a smart wearable device, etc.

For example, referring to fig. 5 in combination, in one possible embodiment, the flexible terminal 1 may include a flexible display module 10 having a curved surface AA, and the protective film 100 covers the curved cover plate of the flexible display module 10. In one possible embodiment, the curved cover plate is curved on two sides or four sides.

For another example, referring to fig. 6 in combination, in another possible embodiment, the flexible terminal 1 may include a flexible display module 10 having a foldable area BB, and the protective film 100 is covered on a flexible foldable cover plate of the flexible display module 10 to protect the cover plate from being scratched, and the application of the protective film is good in the folded state.

In this embodiment, based on the description of the foregoing embodiment, the protective film 100 may be capable of taking into account both scratch resistance and bending resistance of the surface of the flexible cover plate on the flexible display module 10, and the display screen 110 of the flexible terminal 1 has the curved surface AA or the foldable area BB, and further the protective film 100 may also have a flexible attaching portion that is flexibly attached to the curved surface AA or the foldable area BB. In some examples, the thickness of the flexible conformable portion may be varied, such as from a direction of folding or bending, the thickness of the flexible conformable portion may be increased followed by a decrease, or may be held constant and then decreased.

In some possible embodiments, the protective film 100 may further include a plurality of through holes, where the specific positions of the through holes relate to the structure of the flexible terminal 1, and by providing the through holes, components such as a camera, a speaker, etc. may be given way, so as to prevent the photographing of the flexible terminal 1 or the derivation of sound from being affected.

The embodiments described above are only some, but not all, of the embodiments of the present application. The components of the embodiments of the present application, as generally described and illustrated in the figures, may be arranged and designed in a wide variety of different configurations. Accordingly, the detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of protection of the application, but is merely representative of selected embodiments of the application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims. Moreover, all other embodiments that can be made by a person skilled in the art, based on the embodiments of the present application, without making any inventive effort, shall fall within the scope of protection of the present application.

Claims

1. A protective film for protecting a flexible cover sheet, the protective film comprising:

a hardened film over the flexible cover plate;

a flexible substrate located over the hardened film; an optical diamond film over the flexible substrate;

a first buffer layer located between the upper surface of the flexible substrate and the lower surface of the optical diamond film;

the second buffer layer is positioned on the upper surface of the optical diamond film; and

the anti-fingerprint layer is positioned on the upper surface of the second buffer layer;

the first buffer layer is made of SiNx and/or SiOx materials, and the flexible substrate comprises a substrate layer formed by at least one of polyethylene terephthalate, polyimide and cycloolefin polymer;

the thickness of the optical diamond film is smaller than that of the hardened film.

2. The protective film of claim 1, wherein the flexible substrate is bonded to the hardened film on the surface of the flexible cover sheet by a UV-curable adhesive layer.

3. The protective film according to claim 1, wherein the thickness of the optical diamond film is 10nm or less.

4. A flexible display module, characterized in that the flexible display module comprises:

a flexible display screen;

a flexible cover plate positioned on the flexible display screen; and

a protective film according to any one of claims 1-3 on said flexible cover sheet;

5. A flexible terminal comprising the flexible display module of claim 4.