CN117475743A

CN117475743A - Foldable display device

Info

Publication number: CN117475743A
Application number: CN202310630499.3A
Authority: CN
Inventors: 汤家亮; 韩尚辰
Original assignee: Wuhan China Star Optoelectronics Semiconductor Display Technology Co Ltd
Current assignee: Wuhan China Star Optoelectronics Semiconductor Display Technology Co Ltd
Priority date: 2023-05-30
Filing date: 2023-05-30
Publication date: 2024-01-30

Abstract

The invention discloses a foldable display device, which comprises an outer screen area, an inner screen area and a transition area for connecting the outer screen area and the inner screen area, wherein the outer screen area is bent to the back surface of the inner screen area through the transition area; the inner screen area comprises at least two non-bending areas and bending areas positioned between two adjacent non-bending areas; the foldable display device further includes a display panel and a cover layer; the thickness of the covering layer in the outer screen area is larger than that of the covering layer in the inner screen area so as to improve the outer screen strength, and the thickness of the covering layer in the bending area and the transitional area is smaller than that of the covering layer in the non-bending area so as to improve the bending performance of the inner screen.

Description

Foldable display device

Technical Field

The present invention relates to the field of display, and in particular, to a foldable display device.

Background

The flexible screen has the characteristics of light and thin volume, low power consumption, flexibility and the like, and has wider application fields, for example, an integrated flexible screen is used as an inner screen and an outer screen of the folding display device. Because of the difference of the mechanical property requirements of the inner screen and the outer screen, the strength of the outer screen needs to be improved, the bending property of the inner screen needs to be improved, and the strength of the outer screen and the bending property of the inner screen cannot be ensured simultaneously by the existing product.

Disclosure of Invention

The embodiment of the invention provides a foldable display device, which can solve the technical problem that the existing foldable display device cannot ensure the strength of an outer screen and the bending performance of an inner screen at the same time.

The embodiment of the invention provides a foldable display device, which comprises an outer screen area, an inner screen area and a transition area for connecting the outer screen area and the inner screen area, wherein the outer screen area is bent to the back surface of the inner screen area through the transition area; the inner screen area comprises at least two non-bending areas and bending areas positioned between two adjacent non-bending areas;

the foldable display device further includes:

a display panel;

the covering layer covers one side of the display panel and is positioned in the outer screen area, the inner screen area and the transition area;

the thickness of the covering layer in the outer screen area is larger than that of the covering layer in the inner screen area, and the thicknesses of the covering layer in the bending area and the transition area are smaller than that of the covering layer in the non-bending area.

According to the foldable display device provided by the embodiment of the invention, the transition area is provided with a first bending axis, and the bending area is provided with a second bending axis;

the cover layer comprises a first sub-part positioned in the middle area of the transition area and a second sub-part positioned in the edge area of the transition area, and the first sub-part covers the first bending axis; the cover layer comprises a third sub-part positioned in the middle area of the bending area and a fourth sub-part positioned in the edge area of the bending area, and the third sub-part covers the second bending axis;

wherein the thickness of the first sub-portion is smaller than the thickness of the second sub-portion, and/or the thickness of the third sub-portion is smaller than the thickness of the fourth sub-portion.

According to the foldable display device provided by the embodiment of the invention, the thickness of the first sub-part close to the first bending axis is smaller than the thickness of the first sub-part far away from the first bending axis; and/or, the thickness of the third sub-part close to the second bending axis is smaller than the thickness of the third sub-part far away from the second bending axis.

According to the foldable display device provided by the embodiment of the invention, the thickness of the second sub-part close to the first bending axis is smaller than the thickness of the second sub-part far away from the first bending axis; the thickness of the fourth sub-part close to the second bending axis is smaller than that of the fourth sub-part far away from the second bending axis.

According to the foldable display device provided by the embodiment of the invention, the cover layer is recessed from the surface of the transition area, which is far away from the display panel, to the side, which is close to the display panel, to form the first groove, and the cover layer is recessed from the surface of the bending area, which is far away from the display panel, to the side, which is close to the display panel, to form the second groove.

According to the foldable display device provided by the embodiment of the invention, the surface of the cover layer on one side of the transition area close to the display panel is recessed to one side away from the display panel to form a first groove, and the surface of the cover layer on one side of the bending area close to the display panel is recessed to one side away from the display panel to form a second groove.

According to the foldable display device provided by the embodiment of the invention, the foldable display device further comprises a protective layer filled in the first groove and the second groove; when the folding display device is in an unfolding state, the surface of the protective layer, which is far away from the display panel, is flush with the surface of the cover layer, which is far away from the display panel.

According to the foldable display device provided by the embodiment of the invention, the elastic modulus of the protective layer is larger than that of the covering layer.

According to the foldable display device provided by the embodiment of the invention, the material of the cover layer comprises one of unequal-thickness ultrathin glass, polyethylene terephthalate, thermoplastic polyurethane elastomer and optical cement.

According to the foldable display device provided by the embodiment of the invention, the foldable display device further comprises:

the backboard is arranged on one side of the display panel, which is away from the covering layer;

the polaroid is arranged on one side of the display panel, which is close to the covering layer;

a first adhesive layer covering one side of the polarizer away from the display panel, the cover layer being located at one side of the first adhesive layer away from the display panel;

a second adhesive layer covering a side of the cover layer remote from the display panel; and

and the cover plate layer covers one side of the second adhesive layer away from the display panel.

The beneficial effects are that: the foldable display device provided by the embodiment of the invention comprises an outer screen area, an inner screen area and a transition area for connecting the outer screen area and the inner screen area, wherein the inner screen area comprises at least two non-bending areas and bending areas positioned between the adjacent two non-bending areas, the adjacent two non-bending areas of the inner screen area realize inward bending through the bending areas, the back of the inner screen area is bent through the transition area to realize outward bending, the thickness of a covering layer in the outer screen area is larger than that of the covering layer in the inner screen area so as to improve the outer screen strength, and the thickness of the covering layer in the bending areas and the transition area is smaller than that of the covering layer in the non-bending areas so as to improve the bending performance of the inner screen.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are needed in the description of the embodiments will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present invention, and that other 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 foldable display device in a folded state according to an embodiment of the present invention;

fig. 2 is a schematic view of a first structure of a foldable display device in an unfolded state according to an embodiment of the present invention;

fig. 3 is a schematic view of a second structure of the foldable display device in an unfolded state according to the embodiment of the present invention;

FIG. 4 is a schematic view of a first partial enlarged structure of a cover layer of the foldable display device of FIG. 2;

fig. 5 is a schematic view of a second partial enlarged structure of a cover layer of the foldable display device of fig. 2.

101. An outer screen area; 102. an inner screen area; 1021. a non-inflection region; 1022. a bending region; 1022a, a first bending axis; 103. a transition zone; 103a, a second bending axis;

10. a display panel; 20. a cover layer; 21. a first groove; 22. a second groove; 23. a first sub-section; 24. a second sub-section; 25. a third sub-section; 26. a fourth sub-section; 30. a protective layer; 40. a back plate; 50. a polarizer; 60. a first adhesive layer; 70. a second adhesive layer; 80. and a cover plate.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. It will be apparent that the described embodiments are only some, but not all, embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to fall within the scope of the invention.

In the description of the present invention, it should be understood that the terms "length," "width," "thickness," "upper," "lower," and the like indicate an orientation or a positional relationship based on that shown in the drawings, and are merely for convenience of description and simplification of the description, and do not indicate or imply that the apparatus or element in question must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present invention. In the description of the present invention, the meaning of "a plurality" is two or more, unless explicitly defined otherwise.

In the present invention, 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, as well as the first and second features not being in direct contact but being in contact with each other through additional features therebetween.

The embodiment of the invention provides a foldable display device. The following will describe in detail. The following description of the embodiments is not intended to limit the preferred embodiments.

Specifically, referring to fig. 1 and 2, the foldable display device provided in the embodiment of the present invention includes an outer screen area 101, an inner screen area 102, and a transition area 103 connecting the outer screen area 101 and the inner screen area 102, where the outer screen area 101 is bent to the back surface of the inner screen area 102 through the transition area 103; the inner screen region 102 includes at least two non-inflection regions 1021 and an inflection region 1022 located between adjacent ones of the non-inflection regions 1021.

The foldable display device further comprises a display panel 10 and a cover layer 20, wherein the cover layer 20 covers one side of the display panel 10 and is positioned in the outer screen area 101, the inner screen area 102 and the transition area 103; the thickness of the cover layer 20 in the outer screen area 101 is greater than the thickness of the cover layer 20 in the inner screen area 102 to improve the outer screen strength, and the thicknesses of the cover layer 20 in the bending area 1022 and the transition area 103 are smaller than the thickness of the cover layer 20 in the non-bending area 1021 to improve the inner screen bending performance, i.e. the cover layer 20 of the invention adopts different thickness designs in each area of the inner screen and the outer screen, so that the outer screen strength and the inner screen bending performance can be ensured simultaneously.

In this embodiment of the present invention, the foldable display panel 10 includes an outer screen, an inner screen, and a transition portion connecting the outer screen and the inner screen, wherein the outer screen is bent to the back of the inner screen through the transition portion, and the inner screen includes at least two sub-screens and bending portions of two adjacent sub-screens. The outer screen and the inner screen are electrically connected through the transition part, so that the outer screen and the inner screen can be a display screen, and only one end of the outer screen and one end of the inner screen are electrically connected with a control circuit or a battery and other parts, thereby being beneficial to simplifying the structure of the foldable electronic equipment and lightening the foldable electronic equipment. The outer screen is located in the outer screen area 101, the transition portion is located in the transition area 103, the inner screen is located in the inner screen area 102, the sub-screens are located in the non-bending area 1021 and are in one-to-one correspondence with each other, and the bending portion is located in the bending area 1022.

When the foldable display device is in a folded state, the display surface of the inner screen area 102 is folded inwards by the transition area 103, the display surface of the inner screen faces the inner side of the foldable display device, and the inner screen area 102 does not display a picture. The outer screen area 101 is bent to the back surface of the inner screen area 102 through the bending area 1022, the display surface of the outer screen area 101 faces to the outer side of the foldable display device, and the outer screen area 101 displays or does not display a picture, so that small screen display or storage is realized. When the foldable display device is in the unfolded state, the display surfaces of the bending region 1022, the transition region 103, the non-bending region 1021, and the outer screen region 101 may be in the same plane, so as to implement a large screen display.

Specifically, the cover layer 20 is a transparent film layer for protecting the display panel 10. In the embodiment of the present invention, the cover layer 20 covers the light-emitting surface side of the display panel 10.

Note that, in the related art, UTG (UTG, ultra Thin Glass) Ultra Thin Glass is used as the material of the cover layer 20, and UTG Ultra Thin Glass generally refers to flexible Glass having a thickness of less than 100 micrometers, which has an outstanding flexibility characteristic. However, the overall thickness of the UTG ultra-thin glass is too thin and flat, making it difficult for the bending properties and strength of the UTG ultra-thin glass to meet the requirements at the same time. In view of this, the inventors consider that the thickness of the middle of the ultra-thin glass of unequal thickness (UFG, ultra Flexible Glass) is reduced compared to the conventional UTG ultra-thin glass, and the intermediate thickness of the UFG glass can be used as the material of the cover layer 20, and the thicknesses of the transition region 103 and the bending region 1022 can be reduced by utilizing the characteristics of the UFG material, so that the local stress concentration when the foldable display device is folded can be reduced, and the outer screen strength and the inner screen bending performance can be ensured at the same time.

It should be noted that the material of the cover layer 20 is not limited to UFG ultra-thin glass, and the cover layer 20 is made of other flexible materials with adjustable thickness, which is also applicable to the inventive concept of the present invention. Illustratively, the material of the cover layer 20 includes one of ultra-thin glass of unequal thickness, polyethylene terephthalate, thermoplastic polyurethane elastomer, and optical cement.

The number of the non-bending areas 1021 may be plural, and the number of the bending areas 1022 may be plural, it may be understood that the larger the number of the non-bending areas 1021 and the bending areas 1022, the larger the display screen size of the foldable display device is in the unfolded state when the size of each non-bending area 1021 is fixed, which is beneficial to realizing large-screen display; when the size of the whole display screen is fixed, the folding size of the foldable display device is smaller when the foldable display device is in a folded state, so that the storage space is saved.

For clarity of description of the technical solution provided in the present invention, the embodiment of the present invention is described by taking the case that the inner screen includes two sub-screens and one bending portion, that is, the inner screen area 102 includes two non-bending areas 1021 and one bending area 1022 as an example.

In the embodiment of the present invention, the transition region 103 has a first bending axis 1022a, the bending region 1022 has a second bending axis 103a, the transition region 103 bends along the first bending axis 1022a, and the bending region 1022 bends along the second bending axis 103a. Generally, the transition regions 103 are symmetrically disposed along the first bending axis 1022a, and the bending regions 1022 are symmetrically disposed along the second bending axis 103a, and the first bending axis 1022a is parallel to the second bending axis 103a.

Referring to fig. 3, the cover 20 includes a first sub-portion 23 located in a middle region of the transition region 103 and a second sub-portion 24 located in an edge region of the transition region 103, where the first sub-portion 23 covers the first bending axis 1022a; the cover layer 20 includes a third sub-portion 25 located in a middle region of the bending region 1022 and a fourth sub-portion 26 located in an edge region of the bending region 1022, the third sub-portion 25 covering the second bending axis 103a.

It will be appreciated that for any bending region, the bending stress experienced at the bending axis is greater than that experienced in other regions, and fracture is more likely to occur. Therefore, in order to improve stress concentration of a portion of the bending portion near the bending axis, in the embodiment of the present invention, the thickness of the first sub-portion 23 is smaller than the thickness of the second sub-portion 24, and/or the thickness of the third sub-portion 25 is smaller than the thickness of the fourth sub-portion 26, so that bending performance of the first sub-portion 23 and the third sub-portion 25 is improved by thinning the thicknesses of the first sub-portion 23 and the third sub-portion 25.

Further, referring to fig. 4, fig. 4 is different from fig. 3 in that a thickness of the first sub-portion 23 near the first bending axis 1022a is smaller than a thickness of the first sub-portion 23 far from the first bending axis 1022a; and/or the thickness of the third sub-portion 25 near the second bending axis 103a is smaller than the thickness of the third sub-portion 25 away from the second bending axis 103a. In this way, the thickness of the first sub-portion 23 gradually decreases in the direction approaching the first bending axis 1022a, and the thickness of the third sub-portion 25 gradually decreases in the direction approaching the second bending axis 103a, and the bending performance of the first sub-portion 23 and the third sub-portion 25 can be further improved by adopting a gradual change design for the thicknesses of the first sub-portion 23 and the third sub-portion 25.

Further, referring to fig. 3 and 4, a thickness of the second sub-portion 24 near the first bending axis 1022a is smaller than a thickness of the second sub-portion 24 far from the first bending axis 1022a; the thickness of the fourth sub-portion 26 near the second bending axis 103a is smaller than the thickness of the fourth sub-portion 26 away from the second bending axis 103a, i.e. the thickness of the second sub-portion 24 and the thickness of the fourth sub-portion 26 are graded. Since the second sub-portion 24 is connected to the portion of the cover layer 20 located in the non-bending region 1021 or the portion of the cover layer 20 located in the outer screen region 101, the fourth sub-portion 26 is connected to the portion of the cover layer 20 located in the non-bending region 1021, so that two regions with different thicknesses can be gradually transited.

In an embodiment of the present invention, the thicknesses of the transition region 103 and the bending region 1022 may be reduced by forming grooves. Specifically, in one embodiment, the surface of the cover layer 20 on the side of the transition region 103 away from the display panel 10 is recessed to form a first groove 21 toward the side of the display panel 10, and the surface of the cover layer 20 on the side of the bending region 1022 away from the display panel 10 is recessed to form a second groove 22 toward the side of the display panel 10. That is, the opening of the first recess 21 and the opening of the second recess 22 face a side away from the display panel 10.

In another embodiment, referring to fig. 5, the surface of the cover layer 20 on the side of the transition region 103 near the display panel 10 is recessed to form a first groove 21 on the side far away from the display panel 10, and the surface of the cover layer 20 on the side of the bending region 1022 near the display panel 10 is recessed to form a second groove 22 on the side far away from the display panel 10, that is, the opening of the first groove 21 and the opening of the second groove 22 face to the side far away from the display panel 10.

The shape and structure of the first groove 21 and the second groove 22 are not particularly limited, and a cross-sectional shape may be triangular, trapezoidal, or arc. The depth of the first groove 21 may be determined according to the bending radius of the transition region 103, and the depth of the second groove 22 may be determined according to the bending radius of the bending region 1022.

In an embodiment of the present invention, referring to fig. 2, the foldable display device further includes a protective layer 30 filled in the first recess 21 and the second recess 22, and when the foldable display device is in the unfolded state, a surface of the protective layer 30 on a side away from the display panel 10 is flush with a surface of the cover layer 20 on a side away from the display panel 10, so as to fill the first recess 21 and the second recess 22, so that the surface of the cover layer 20 is flat.

The elastic modulus of the protective layer 30 is greater than that of the cover layer 20 to enhance the flexibility of the foldable display device. In some embodiments, the Young's modulus of the protective layer 30 is 60-80 GPa and the pattern modulus of the cover layer 20 is 2-6 GPa.

Specifically, in the embodiment of the present invention, the protective layer 30 is made of a flexible material, and optionally, the material of the protective layer 30 includes polyurethane or modified polyurethane.

Specifically, in one embodiment, the thickness of the cover layer 20 in the outer screen region 101 ranges from 150 micrometers to 300 micrometers, the thickness of the cover layer 20 in the non-bending region 1021 ranges from 100 micrometers to 300 micrometers, the thickness of the cover layer 20 in the transition region 103 ranges from 20 micrometers to 50 micrometers, and the thickness of the cover layer 20 in the bending region 1022 ranges from 20 micrometers to 50 micrometers.

Specifically, in another embodiment, the thickness of the cover layer 20 in the outer screen region 101 ranges from 150 micrometers to 300 micrometers, the thickness of the cover layer 20 in the non-bending region 1021 ranges from 20 micrometers to 50 micrometers, the thickness of the cover layer 20 in the transition region 103 ranges from 20 micrometers to 50 micrometers, and the thickness of the cover layer 20 in the bending region 1022 ranges from 20 micrometers to 50 micrometers.

In an embodiment of the present invention, the foldable display device further includes a back plate 40, a polarizer 50, a first adhesive layer 60, a second adhesive layer 70, and a cover plate 80. The back plate 40 is disposed on a side of the display panel 10 facing away from the cover layer 20; the polarizer 50 is disposed on one side of the display panel 10 near the cover layer 20; the first adhesive layer 60 covers a side of the polarizer 50 away from the display panel 10, and the cover layer 20 is positioned at a side of the first adhesive layer 60 away from the display panel 10; the second adhesive layer 70 covers a side of the cover layer 20 remote from the display panel 10; the cover plate 80 covers a side of the second adhesive layer 70 remote from the display panel 10.

Specifically, the foldable display device may be at least one of a smart phone (smart phone), a tablet computer (tablet personal computer), a mobile phone (mobile phone), a video phone, an electronic book reader (e-book reader), a laptop (laptop PC), a netbook computer (netbook), a workstation (workstation), a server, a personal digital assistant (personal digital assistant), a portable media player (portable multimedia player), an MP3 player, a mobile medical machine, a camera, a game console, a digital camera, a car navigator, an electronic billboard, an automatic teller machine, a smart band, a smart watch, a Virtual Reality (VR) device, or a mobile device (web device). The above embodiments have been described in detail for the display panel, and therefore, in the embodiments of the present invention, the display panel is not described in detail.

In the foregoing embodiments, the descriptions of the embodiments are emphasized, and for parts of one embodiment that are not described in detail, reference may be made to related descriptions of other embodiments.

The above description of the foldable display device provided by the embodiment of the present invention has been provided in detail, and specific examples are applied to illustrate the principle and implementation of the present invention, and the above description of the embodiment is only used to help understand the technical solution and core idea of the present invention; those of ordinary skill in the art will appreciate that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the invention.

Claims

1. The foldable display device is characterized by comprising an outer screen area, an inner screen area and a transition area for connecting the outer screen area and the inner screen area, wherein the outer screen area is bent to the back surface of the inner screen area through the transition area; the inner screen area comprises at least two non-bending areas and bending areas positioned between two adjacent non-bending areas;

the foldable display device further includes:

a display panel;

2. The foldable display device of claim 1, wherein the transition region has a first bend axis and the bend region has a second bend axis;

3. The foldable display device of claim 2, wherein a thickness of the first sub-portion proximate the first bending axis is less than a thickness of the first sub-portion distal the first bending axis; and/or, the thickness of the third sub-part close to the second bending axis is smaller than the thickness of the third sub-part far away from the second bending axis.

4. A foldable display device as recited in claim 3, wherein a thickness of said second sub-portion proximate said first bending axis is less than a thickness of said second sub-portion distal said first bending axis; the thickness of the fourth sub-part close to the second bending axis is smaller than that of the fourth sub-part far away from the second bending axis.

5. The foldable display device of claim 1, wherein the cover layer is recessed from a surface of the transition region on a side away from the display panel to a side proximate to the display panel to form a first recess, and wherein the cover layer is recessed from a surface of the bend region on a side away from the display panel to a side proximate to the display panel to form a second recess.

6. The foldable display device of claim 1, wherein the cover layer is recessed from a surface of the transition region on a side closer to the display panel to a side farther from the display panel to form a first recess, and wherein the cover layer is recessed from a surface of the bend region on a side closer to the display panel to a side farther from the display panel to form a second recess.

7. The foldable display device of claim 5 or 6, further comprising a protective layer filled in the first and second grooves; when the folding display device is in an unfolding state, the surface of the protective layer, which is far away from the display panel, is flush with the surface of the cover layer, which is far away from the display panel.

8. The foldable display device of claim 7, wherein the protective layer has a modulus of elasticity that is greater than a modulus of elasticity of the cover layer.

9. The foldable display device of claim 1, wherein the material of the cover layer comprises any one of ultra-thin glass of unequal thickness, polyethylene terephthalate, thermoplastic polyurethane elastomer, and optical cement.

10. The foldable display device of claim 1, wherein the foldable display device further comprises: