WO2020113840A1 - Cover window and flexible display device - Google Patents

Abstract

A cover window (1) for a flexible display device (2) comprises a bendable portion (11) and an unbandable portion (12). The bendable portion (11) has a Young's modulus lower than a Young's modulus of the unbandable portion (12). The bendable portion (11) can pass a bendability test because of the lower Young's modulus while the unbandable portion (12) can pass a pressure test because of the higher Young's modulus. The invention solves a technical problem in the art in which an unbendable portion of a cover window cannot pass a pressure test easily.

Description

Protective cover plate and flexible display device Technical field

The present application relates to the field of display, in particular to a protective cover and a flexible display device.

Background technique

In recent years, OLED display technology is gradually popularizing in the mobile phone and TV markets, and the yield rate has been greatly improved. The status of its next-generation display technology has been unshakable, and OLED-based flexible display is an important research and development direction of future display technology.

Whether the flexible screen is curved inward or outward, the surface has a protective film called a cover window (Cover Window). Its purpose is to improve the hardness, scratch resistance of the OLED flexible screen, and to protect the internal film materials (such as Touch panel or polarizer, etc.).

The cover window is composed of two materials with different Young's modulus. In order to pass the bending test of the bending part, the existing protective cover sets the Young's modulus of the protection cover plate relatively low. However, the hardness of the non-bent part of the protective cover is low, and it is difficult to pass the pressure test.

That is, the existing protective cover has a technical problem that it is difficult for the non-bent portion to pass the pressure test.

technical problem

The present application provides a protective cover and a flexible display device to solve the technical problem that the non-bent portion of the existing protective cover is difficult to pass the pressure test.

Technical solution

To solve the above problems, the technical solutions provided by this application are as follows:

An embodiment of the present application provides a protective cover plate for a flexible display device, the flexible display device includes a bending area and a non-bending area, the protective cover plate includes a bending portion located in the bending area, and In the non-bent portion located in the non-bending area, the Young's modulus of the curved portion is smaller than the Young's modulus of the non-bent portion.

In the protective cover plate of the present application, the protective cover plate includes a first material layer and a second material layer, the Young's modulus of the first material layer is smaller than the Young's modulus of the second material layer, so The total film thickness of the curved portion is equal to the total film thickness of the non-curved portion; the thickness of the second material layer of the curved portion is smaller than the thickness of the second material layer of the non-curved portion.

In the protective cover of the present application, the thickness of the second material layer of the curved portion is the same, and the thickness of the second material layer of the non-curved portion is the same.

In the protective cover of the present application, the thickness of the second material layer of the curved portion is the same, and the thickness of the second material layer of the non-curved portion gradually increases from the curved portion to the edge.

In the protective cover of the present application, the thickness of the second material layer of the curved portion is different, and gradually increases from the first non-curved portion to the second non-curved portion.

In the protective cover plate of the present application, the thickness of the second material layer of the curved portion is different, and decreases from the first non-curved portion to the second non-curved portion and then increases.

In the protective cover plate of the present application, the thickness of the second material layer of the curved portion is different, and changes periodically from the first non-curved portion to the second non-curved portion.

In the protective cover plate of the present application, the protective cover plate includes a first material layer, a second material layer, and a third material layer, and the first material layer is located on the second material layer and the third material layer Between, the Young's modulus of the first material layer is less than the Young's modulus of the second material layer, and the Young's modulus of the first material layer is less than the Young's modulus of the third material layer , The total thickness of the film layer of the curved portion is equal to the total thickness of the film layer of the non-curved portion; the thickness of the second material layer of the curved portion is smaller than the thickness of the second material layer of the non-curved portion.

In the protective cover of the present application, the thickness of the second material layer of the curved portion is the same, and the thickness of the second material layer of the non-curved portion is the same.

In the protective cover of the present application, the thickness of the third material layer of the curved portion is smaller than the thickness of the third material layer of the non-curved portion.

In the protective cover of the present application, the third material layer of the curved portion has the same thickness, and the third material layer of the non-curved portion has the same thickness.

In the protective cover of the present application, the thickness of the second material layer of the bent portion is the same as the thickness of the third material layer of the bent portion.

In the protective cover of the present application, the thickness of the second material layer of the non-curved portion is the same as the thickness of the third material layer of the non-curved portion.

In the protective cover plate of the present application, the Young's modulus of the second material layer is the same as the Young's modulus of the third material layer.

An embodiment of the present application provides a flexible display device, which includes a flexible display panel and a protective cover plate for protecting the flexible display panel. The flexible display device includes a bending area and a non-bending area, and the protection cover plate It includes a bending portion located in the bending area and a non-bending portion located in the non-bending area, and the Young's modulus of the bending portion is smaller than the Young's modulus of the non-bending portion.

In the flexible display device of the present application, the protective cover includes a first material layer and a second material layer, the Young's modulus of the first material layer is smaller than the Young's modulus of the second material layer, so The total film thickness of the curved portion is equal to the total film thickness of the non-curved portion; the thickness of the second material layer of the curved portion is smaller than the thickness of the second material layer of the non-curved portion.

In the flexible display device of the present application, the thickness of the second material layer of the curved portion is the same, and the thickness of the second material layer of the non-curved portion is the same.

In the flexible display device of the present application, the protective cover includes a first material layer, a second material layer, and a third material layer, and the first material layer is located on the second material layer and the third material layer Between, the Young's modulus of the first material layer is less than the Young's modulus of the second material layer, and the Young's modulus of the first material layer is less than the Young's modulus of the third material layer , The total thickness of the film layer of the curved portion is equal to the total thickness of the film layer of the non-curved portion; the thickness of the second material layer of the curved portion is smaller than the thickness of the second material layer of the non-curved portion.

In the flexible display device of the present application, the thickness of the second material layer of the curved portion is the same, and the thickness of the second material layer of the non-curved portion is the same.

In the flexible display device of the present application, the thickness of the second material layer of the curved portion is the same as the thickness of the third material layer of the curved portion, and the thickness of the second material layer of the non-curved portion is the same as that of the non-curved portion The third material layer has the same thickness.

Beneficial effect

The present application provides a new protective cover plate and a flexible display device. The protective cover plate includes a curved portion located in the bending area and a non-bending portion located in the non-bending area. The modulus is smaller than the Young's modulus of the non-bent part; in this way, because the bent part of the protective cover plate has a lower Young's modulus, it can pass the bendability test, while the non-bent part (generally corresponds to the display screen Area) has a high Young's modulus and can pass the pressure test, which solves the technical problem of the existing protective cover plate that the non-bent portion is difficult to pass the pressure test.

BRIEF DESCRIPTION

In order to more clearly explain the embodiments or the technical solutions in the prior art, the following will briefly introduce the drawings used in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only inventions. For some embodiments, those of ordinary skill in the art can obtain other drawings based on these drawings without paying any creative labor.

FIG. 1 is a first schematic cross-sectional view of a protective cover provided by an embodiment of the present application.

2 is a second schematic cross-sectional view of a protective cover provided by an embodiment of the present application.

FIG. 3 is a third schematic cross-sectional view of a protective cover provided by an embodiment of the present application.

4 is a fourth schematic cross-sectional view of a protective cover provided by an embodiment of the present application.

5 is a fifth cross-sectional schematic diagram of a protective cover provided by an embodiment of the present application.

6 is a sixth cross-sectional schematic diagram of a protective cover provided by an embodiment of the present application.

7 is a schematic diagram of a display device provided by an embodiment of the present application.

8 is a schematic diagram of the film layer of the existing cover plate.

9 is a schematic diagram of a film layer of a protective cover provided by an embodiment of the present application.

FIG. 10 is a schematic diagram of a comparison between the force deformation of the existing cover plate and the protective cover plate provided by the embodiment of the present application.

FIG. 11 is a schematic diagram of stress during deformation of a protective cover provided by an embodiment of the present application.

Embodiments of the invention

The descriptions of the following embodiments refer to additional drawings to illustrate specific embodiments that can be implemented in the present application. Directional terms mentioned in this application, such as [upper], [lower], [front], [back], [left], [right], [inner], [outer], [side], etc., are for reference only Attach the direction of the schema. Therefore, the directional language used is to illustrate and understand this application, not to limit this application. In the figure, units with similar structures are indicated by the same reference numerals.

In view of the technical problem that the non-bent portion of the existing protective cover is difficult to pass the pressure test, the embodiments of the present application can solve this problem.

As shown in FIG. 1, an embodiment of the present application provides a protective cover plate 1 for a flexible display device 2. The flexible display device 2 includes a bending area SS and a non-bending area NS. The protective cover plate 1 includes The bending portion 11 located in the bending area SS, and the non-bending portion 12 (including the first non-bending portion 12a and the second non-bending portion 12b in FIG. 1) located in the non-bending area NS, the The Young's modulus of the bent portion 11 is smaller than the Young's modulus of the non-bent portion 12.

The Young's modulus refers to the Young's modulus of the curved portion 11/non-curved portion 12, and the curved portion 11 / non-curved portion 12 exhibits different Young's modulus according to the film material or the thickness of the film layer. .

The present application provides a new protective cover plate including a curved portion located in the bending area and a non-bending portion located in the non-bending area, the Young's modulus of the curved portion is less than The Young's modulus of the non-bent part; thus, since the bent part of the protective cover plate has a lower Young's modulus, it can pass the bendability test, while the non-bent part (generally corresponding to the display screen area) has a higher The high Young's modulus can pass the pressure test, which solves the technical problem that the non-bent part of the existing protective cover is difficult to pass the pressure test.

The manner in which the Young's modulus of the curved portion 11 is smaller than the Young's modulus of the non-curved portion 12 may be achieved by selecting a suitable material, for example, the curved portion 11 and the non-curved portion 12 use different Young's modulus Material, so that the Young's modulus of the curved portion 11 is smaller than the Young's modulus of the non-curved portion 12, or it can be achieved by using different film thicknesses.

The biggest difference between the flexible AMOLED display and the general flat display in the module structure is that the glass cover (Cover) cannot be used like the general flat display Glass), because the bendability of glass is low, the bending process is fragile. The cover materials used in flexible AMOLED displays today are all plastic materials CPI. However, display products require the surface to be resistant to scratches and impacts, and plastic materials are inherently not as hard as glass. Therefore, general commercial plastic covers will be coated with a hard layer of anti-scratch material (HC, Hard Coating). The plastic cover includes a substrate and a reinforced coating. The substrate is generally made of transparent polyimide (CPI), and the reinforced coating can be used for single-side coating (Single-side HC) and double-side coating (Double-side coating) HC).

The specific application examples will be described in detail below.

In one embodiment, as shown in FIG. 2, the protective cover plate 1 includes a first material layer S1 and a second material layer S2, and the first material layer S1 has a Young's modulus less than the second material layer S2 Young's modulus of the film, the total thickness H1 of the film portion of the curved portion 11 is equal to the total film thickness H2 of the non-curved portion 12; the thickness h21 of the second material layer S2 of the curved portion is smaller than that of the non-curved portion The second material layer S2 has a thickness h22.

The first material layer S1 generally uses transparent polyimide (CPI), and the second material layer S2 uses a hard scratch-resistant material (HC, Hard Coating).

In one embodiment, as shown in FIG. 2, the thickness h21 of the second material layer S2 of the curved portion 11 is the same, and the thickness h22 of the second material layer S2 of the non-curved portion 12 is the same. That is, in the curved portion 11 and the non-curved portion 12, the second material layer S2 is uniformly arranged, and the arrangement is simple in this way.

In one embodiment, the thickness h21 of the second material layer S2 of the curved portion 11 is the same, and the thickness h22 of the second material layer S2 of the non-curved portion 12 gradually increases from the curved portion 11 to the edge.

In one embodiment, the thickness h21 of the second material layer S2 of the curved portion 11 is different, and gradually increases from the first non-curved portion to the second non-curved portion.

In one embodiment, the thickness h21 of the second material layer S2 of the curved portion 11 is different, and decreases from the first non-curved portion to the second non-curved portion and then increases.

In one embodiment, the thickness h21 of the second material layer S2 of the curved portion 11 is different, and changes periodically from the first non-curved portion to the second non-curved portion.

In an embodiment, as shown in FIG. 3, the protective cover 1 includes a first material layer S1, a second material layer S2, and a third material layer S3, and the first material layer S1 is located in the second Between the material layer S2 and the third material layer S3, the Young's modulus of the first material layer S1 is smaller than the Young's modulus of the second material layer S2, and the Young's modulus of the first material layer S1 The modulus is smaller than the Young's modulus of the third material layer S3, and the total thickness H1 of the film layer of the curved portion 11 is equal to the total thickness H2 of the film layer of the non-curved portion 12; the first material of the curved portion 11 The thickness h11 of the layer S1 is greater than the thickness h12 of the first material layer S1 of the non-bent portion 12.

The first material layer S1 generally uses transparent polyimide (CPI), and the second material layer S2 and the third material layer S3 use hard scratch resistant materials (HC, Hard Coating).

In one embodiment, as shown in FIG. 3, the thickness h21 of the second material layer S2 of the curved portion 11 is smaller than the thickness h22 of the second material layer S2 of the non-curved portion 12.

In one embodiment, as shown in FIG. 3, the thickness h21 of the second material layer S2 of the curved portion 11 is the same, and the thickness h22 of the second material layer S2 of the non-curved portion 12 is the same.

In one embodiment, as shown in FIG. 3, the thickness h31 of the third material layer S3 of the curved portion 11 is smaller than the thickness h32 of the third material layer S3 of the non-curved portion 12.

In one embodiment, as shown in FIG. 3, the thickness h31 of the third material layer S3 of the curved portion 11 is the same, and the thickness h32 of the third material layer S3 of the non-curved portion 12 is the same.

In one embodiment, as shown in FIG. 3, the thickness h21 of the second material layer S2 of the curved portion 11 is the same as the thickness h31 of the third material layer S3 of the curved portion 11.

In one embodiment, as shown in FIG. 3, the thickness h22 of the second material layer S2 of the non-curved portion 12 is the same as the thickness h31 of the third material layer S3 of the curved portion 11.

In an embodiment, the Young's modulus of the second material layer S2 is the same as the Young's modulus of the third material layer S3, for example, formed by using the same material.

As shown in FIG. 4, an embodiment of the present application provides a protective cover plate 1 for a flexible display device 2. The flexible display device 2 includes a bending area SS and a non-bending area NS. The protective cover plate 1 includes The bending portion 11 located in the bending area SS, the non-bending portion 12 located in the non-bending area NS (the non-bending portion 12a and the non-bending portion 12b in FIG. 4), and the bending portion 11 and In the transition portion 14 between the non-curved portion 12 (the non-curved portion 13a and the non-curved portion 13b in FIG. 4), the Young's modulus of the curved portion 11 is smaller than the Young's modulus of the non-curved portion 12 The Young's modulus of the transition portion 13 is larger than the Young's modulus of the curved portion 11 and smaller than the Young's modulus of the non-bent portion 12.

In one embodiment, as shown in FIG. 4, the transition portion 13 is located in the bending zone SS.

The different Young's modulus of different parts can be achieved by choosing a suitable material, for example, the bending part 11, the non-bending part 12 and the transition part 13 are made of different Young's modulus materials, so that different parts can be partially realized Different Young's modulus can also be achieved by using different film thicknesses.

In an embodiment, as shown in FIG. 5, the protective cover plate 1 includes a first material layer S1 and a second material layer S2, and the first material layer S1 has a Young's modulus less than the second material layer S2 The Young's modulus of the film, the total thickness H1 of the curved portion 11, the total thickness H2 of the non-curved portion 12, and the total thickness H3 of the transition portion 13 are the same; the second portion of the curved portion 11 The thickness h21 of the material layer is smaller than the thickness h23 (average thickness) of the second material layer of the transition portion 13, and the thickness h23 of the second material layer of the transition portion 13 is smaller than the thickness h22 of the second material layer of the non-curved portion 13.

In an embodiment, as shown in FIG. 5, the thickness h21 of the second material layer S2 of the curved portion 11 is the same, the thickness h22 of the second material layer S2 of the non-curved portion 12 is the same, and the thickness of the transition portion 13 The thickness h22 of the second material layer S2 gradually increases from the curved portion 11 to the non-curved portion 12. That is, in the curved portion 11 and the non-curved portion 12, the second material layer S2 is uniformly arranged, and the arrangement is simple in this way.

In one embodiment, as shown in FIG. 5, the cross section of the contact surface m between the second material layer S2 and the first material layer S1 of the transition portion 13 is a straight line.

In an embodiment, the cross-section of the contact surface m between the second material layer S2 and the first material layer S1 of the transition portion 13 is a curve or an arc, or a combination lamp mode of a curve and a straight line.

In one embodiment, as shown in FIG. 6, the protective cover 1 includes a first material layer S1, a second material layer S2, and a third material layer S3, and the first material layer S1 is located in the second Between the material layer S2 and the third material layer S3, the Young's modulus of the first material layer S1 is smaller than the Young's modulus of the second material layer S2, and the Young's modulus of the first material layer S1 The modulus is smaller than the Young's modulus of the third material layer S3, the total film thickness H1 of the curved portion 11, the total film thickness H2 of the non-curved portion 12, and the total film thickness H3 of the transition portion 13. The same; the thickness h11 of the first material layer S1 of the curved portion 11 is greater than the thickness h13 (average thickness value) of the first material layer of the transition portion 13, the thickness h13 of the first material layer of the transition portion 13 is greater than the non- The thickness h12 of the first material layer S1 of the bent portion 12.

In an embodiment, as shown in FIG. 6, the thickness h21 of the second material layer S2 of the curved portion 11 is smaller than the thickness h23 of the second material layer of the transition portion 13, and the second material layer of the transition portion 13 The thickness h23 is smaller than the thickness h22 of the second material layer S2 of the non-bent portion 12.

In an embodiment, as shown in FIG. 6, the thickness h21 of the second material layer S2 of the curved portion 11 is the same, the thickness h22 of the second material layer S2 of the non-curved portion 12 is the same, and the thickness of the transition portion 13 The thickness h22 of the second material layer gradually increases from the curved portion 11 to the non-curved portion 12.

In an embodiment, as shown in FIG. 6, the thickness h31 of the third material layer S3 of the curved portion 11 is smaller than the thickness h33 of the third material layer S3 of the transition portion 13, and the third material of the transition portion 13 The thickness h33 of the layer S3 is smaller than the thickness h32 of the third material layer S3 of the non-bent portion 12.

In one embodiment, as shown in FIG. 6, the thickness h31 of the third material layer S3 of the curved portion 11 is the same, and the thickness h32 of the third material layer S3 of the non-curved portion 12 is the same.

In one embodiment, as shown in FIG. 6, the thickness h21 of the second material layer S2 of the curved portion 11 is the same as the thickness h31 of the third material layer S3 of the curved portion 11.

In one embodiment, as shown in FIG. 6, the thickness h22 of the second material layer S2 of the non-curved portion 12 is the same as the thickness h31 of the third material layer S3 of the curved portion 11.

In an embodiment, the Young's modulus of the second material layer S2 is the same as the Young's modulus of the third material layer S3, for example, formed by using the same material.

In one embodiment, as shown in FIG. 6, the cross section of the contact surface m1 of the second material layer S2 and the first material layer S1 of the transition portion 13 is a straight line.

In one embodiment, the cross-section of the contact surface m1 of the second material layer S2 and the first material layer S1 of the transition portion 13 is a curve or a circular arc, or a combined lamp mode of a curve and a straight line.

In one embodiment, as shown in FIG. 6, the cross section of the contact surface m2 between the third material layer S3 of the transition portion 13 and the first material layer S1 is a straight line.

In an embodiment, the cross-section of the contact surface m2 between the third material layer S3 and the first material layer S1 of the transition portion 13 is a curve or a circular arc, or a combined lamp mode of a curve and a straight line.

Correspondingly, in one embodiment, the present application also provides a flexible display device, which includes a flexible display panel and a protective cover for protecting the flexible display panel, the flexible display device includes a bending area and a non-bending A folding area, the protective cover plate includes a bending portion located in the bending area, and a non-bending portion located in the non-bending area, and the Young's modulus of the bending portion is smaller than that of the non-bending portion Moduli.

In this way, since the curved part of the protective cover has a low Young's modulus, it can pass the bendability test, while the non-bent part (generally corresponding to the display screen area) has a high Young's modulus, which can pass the pressure test It solves the technical problem that the non-bent part of the existing protective cover is difficult to pass the pressure test.

In an embodiment, the protective cover includes a first material layer and a second material layer, the first material layer has a Young's modulus less than the second material layer, the bending The total film thickness of the portion is equal to the total film thickness of the non-curved portion; the thickness of the second material layer of the curved portion is less than the thickness of the second material layer of the non-curved portion.

In one embodiment, the thickness of the second material layer of the curved portion is the same, and the thickness of the second material layer of the non-curved portion is the same.

In an embodiment, the protective cover includes a first material layer, a second material layer, and a third material layer, the first material layer is located between the second material layer and the third material layer , The Young's modulus of the first material layer is less than the Young's modulus of the second material layer, the Young's modulus of the first material layer is less than the Young's modulus of the third material layer, so The total film thickness of the curved portion is equal to the total film thickness of the non-curved portion; the thickness of the second material layer of the curved portion is smaller than the thickness of the second material layer of the non-curved portion.

In one embodiment, the thickness of the second material layer of the curved portion is the same, and the thickness of the second material layer of the non-curved portion is the same.

In one embodiment, the thickness of the third material layer of the curved portion is smaller than the thickness of the third material layer of the non-curved portion.

In an embodiment, the third material layer of the curved portion has the same thickness, and the third material layer of the non-curved portion has the same thickness.

In an embodiment, the thickness of the second material layer of the curved portion is the same as the thickness of the third material layer of the curved portion, and the thickness of the second material layer of the non-curved portion is the same as the third thickness of the non-curved portion The thickness of the material layer is the same.

In one embodiment, the Young's modulus of the second material layer is the same as the Young's modulus of the third material layer.

Flexible display screens have many advantages such as lightness, thinness, and portability, and are important development directions for OLED display technology. The Cover Window of the OLED screen must ensure sufficient hardness and good bending resistance.

As shown in FIG. 7, assuming that the bending radius of the OLED flexible display screen is R (the current mainstream product is 3mm or 5mm), it includes a bending area SS with a length (or arc length) of L0=π*R, and two The non-bent areas NS1 and NS2 of length L are obviously L is much larger than L0.

As shown in FIG. 8, the existing plastic cover window structure 80 includes: a uniform thickness Harding Coating film layer 81 in the upper part, and a uniform thickness CPI film layer 82 in the lower part. Technical problems that the Ministry has difficulty passing the stress test.

In this embodiment, the Hard Coating thickness with high Young's modulus is increased in the non-bending area of the OLED screen, and the CPI thickness with low Young's modulus is increased in the bending area, so that the Cover Window and the Panel Hardness, at the same time, reduces the stress of the Panel during bending in the bending area, ensuring good bending resistance, thereby increasing the number of bending times during use. The design of the cover window device in the bending area and the non-bending area of the OLED screen with different thicknesses can improve the display effect of the flexible screen, enhance the user experience of the flexible display, and finally reach the mass production index of the flexible screen. The flexible display industry brings high economic benefits.

This embodiment provides a Cover Window structure that can both increase the rigidity of the flexible OLED screen and take into account the bendability of the flexible OLED screen. The window structure is composed of two layers of film materials, Hard Coating and CPI. The thickness of the Hard Coating in the non-bending area is higher than the thickness of the non-bending area; the thickness of the CPI in the bending area is higher than the thickness of the bending area.

As shown in FIG. 9, the new Cover Window structure 90 provided in this embodiment for taking into account the rigidity and bendability of the flexible OLED display screen is composed as follows: a non-uniform thickness Harding Coating film layer 91 on the upper part and a non-uniform thickness on the lower door CPI film layer 92 of uniform thickness.

FIG. 10 illustrates the comparison between the deformation of the existing Cover Window structure and the flexible screen of the new Cover Window structure proposed in this embodiment during the pencil hardness test in the non-bending area. As shown in FIG. 10, under the same pressure F, the deformation of the existing cover plate (shown as a in FIG. 10) is larger, while the deformation of the plastic cover plate (shown as b in FIG. 10) provided in this embodiment is smaller, which This is because the plastic cover provided in this embodiment uses thickened Harding The rigidity of the Cover Window device of the Coating structure provides better support in the normal direction of the flexible screen, the sag depth caused by the external load is reduced, and the performance of the flexible screen against external loads is improved to ensure that the flexible laminated structure can pass smoothly Pencil hardness and nano-indentation test.

At the same time, as shown in FIG. 11, the Cover Window device with a thickened CPI structure in the bending area is weak, and the stress during bending is small, which not only improves the hardness of the non-bending area, but also takes into account the bending Bending resistance of the zone.

According to the above embodiment, it is known that:

The present application provides a new protective cover plate and a flexible display device. The protective cover plate includes a curved portion located in the bending area and a non-bending portion located in the non-bending area. The modulus is smaller than the Young's modulus of the non-bent part; in this way, because the bent part of the protective cover plate has a lower Young's modulus, it can pass the bendability test, while the non-bent part (generally corresponds to the display screen Area) has a high Young's modulus and can pass the pressure test, which solves the technical problem of the existing protective cover plate that the non-bent portion is difficult to pass the pressure test.

In summary, although the present application has been disclosed as preferred embodiments above, the above preferred embodiments are not intended to limit the present application. Those of ordinary skill in the art can make various changes without departing from the spirit and scope of the present application Such changes and retouching, so the scope of protection of this application shall be subject to the scope defined by the claims.

Claims (20)

A protective cover plate for a flexible display device, the flexible display device includes a bending area and a non-bending area, the protective cover plate includes a bending portion located in the bending area, and the non-bending area In the non-bent portion of the folded area, the Young's modulus of the curved portion is smaller than the Young's modulus of the non-bent portion. The protective cover plate according to claim 1, wherein the protective cover plate comprises a first material layer and a second material layer, and the first material layer has a Young's modulus smaller than that of the second material layer Modulus, the total thickness of the film layer of the curved portion is equal to the total thickness of the film layer of the non-curved portion; the thickness of the second material layer of the curved portion is smaller than the thickness of the second material layer of the non-curved portion. The protective cover plate according to claim 2, wherein the thickness of the second material layer of the curved portion is the same, and the thickness of the second material layer of the non-curved portion is the same. The protective cover plate according to claim 2, wherein the thickness of the second material layer of the curved portion is the same, and the thickness of the second material layer of the non-curved portion gradually increases from the curved portion to the edge. The protective cover plate according to claim 2, wherein the thickness of the second material layer of the curved portion is different, and gradually increases from the first non-curved portion to the second non-curved portion. The protective cover plate according to claim 2, wherein the thickness of the second material layer of the curved portion is different, and decreases from the first non-curved portion to the second non-curved portion and then increases. The protective cover plate according to claim 2, wherein the thickness of the second material layer of the curved portion is different, and changes periodically from the first non-curved portion to the second non-curved portion. The protective cover plate according to claim 1, wherein the protective cover plate comprises a first material layer, a second material layer and a third material layer, the first material layer is located on the second material layer and the Between the third material layers, the Young's modulus of the first material layer is smaller than that of the second material layer, and the Young's modulus of the first material layer is smaller than that of the third material layer For Young's modulus, the total thickness of the film layer of the curved portion is equal to the total thickness of the film layer of the non-curved portion; the thickness of the second material layer of the curved portion is smaller than the thickness of the second material layer of the non-curved portion. The protective cover plate according to claim 8, wherein the thickness of the second material layer of the curved portion is the same, and the thickness of the second material layer of the non-curved portion is the same. The protective cover plate according to claim 8, wherein the thickness of the third material layer of the curved portion is smaller than the thickness of the third material layer of the non-curved portion. The protective cover plate according to claim 8, wherein the third material layer of the curved portion has the same thickness, and the third material layer of the non-curved portion has the same thickness. The protective cover according to claim 8, wherein the thickness of the second material layer of the bent portion is the same as the thickness of the third material layer of the bent portion. The protective cover plate according to claim 8, wherein the thickness of the second material layer of the non-curved portion is the same as the thickness of the third material layer of the non-curved portion. The protective cover plate according to claim 8, wherein the Young's modulus of the second material layer is the same as the Young's modulus of the third material layer. A flexible display device, including a flexible display panel and a protective cover plate for protecting the flexible display panel, the flexible display device includes a bending area and a non-bending area, the protective cover plate includes a In the bending portion in the bending area and the non-bending portion located in the non-bending area, the Young's modulus of the bending portion is smaller than the Young's modulus of the non-bending portion. The flexible display device according to claim 15, wherein the protective cover includes a first material layer and a second material layer, the first material layer having a Young's modulus less than that of the second material layer Modulus, the total thickness of the film layer of the curved portion is equal to the total thickness of the film layer of the non-curved portion; the thickness of the second material layer of the curved portion is smaller than the thickness of the second material layer of the non-curved portion. The flexible display device according to claim 16, wherein the second material layer of the curved portion has the same thickness and the second material layer of the non-curved portion has the same thickness. The flexible display device according to claim 15, wherein the protective cover comprises a first material layer, a second material layer and a third material layer, the first material layer is located between the second material layer and the Between the third material layers, the Young's modulus of the first material layer is smaller than that of the second material layer, and the Young's modulus of the first material layer is smaller than that of the third material layer For Young's modulus, the total thickness of the film layer of the curved portion is equal to the total thickness of the film layer of the non-curved portion; the thickness of the second material layer of the curved portion is smaller than the thickness of the second material layer of the non-curved portion. The flexible display device according to claim 18, wherein the second material layer of the curved portion has the same thickness and the second material layer of the non-curved portion has the same thickness. The flexible display device according to claim 18, wherein the thickness of the second material layer of the curved portion is the same as the thickness of the third material layer of the curved portion, and the thickness of the second material layer of the non-curved portion is the same as the thickness The thickness of the third material layer of the non-bent portion is the same.