CN117222962A

CN117222962A - Display assembly for foldable electronic device

Info

Publication number: CN117222962A
Application number: CN202180097317.XA
Authority: CN
Inventors: 纳贾·伦罗斯
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2021-07-15
Filing date: 2021-07-15
Publication date: 2023-12-12
Also published as: WO2023284959A1

Abstract

A display assembly (1) for an electronic device (2), comprising: a flexible display structure (3) configured to bend around a main axis (A1); a substrate (5) superimposed on the flexible display structure (3) and comprising a first material. The matrix (5) comprises a grating structure (6) arranged adjacent to the main axis (A1) of the flexible structure (3), the grating structure (6) comprising a second material having a lower density than the first material. The first material may comprise aluminosilicate glass, fused silica glass, or any suitable transparent multicomponent glass. The grating structure (6) may be formed by a plurality of elongated channels (6 a), each elongated channel (6 a) extending along a central axis (A2), the central axis (A2) extending perpendicular or parallel to the main axis (A1).

Description

Display assembly for foldable electronic device

Technical Field

The present invention relates to a display assembly for an electronic device, the display assembly comprising a flexible display structure configured to bend around a main axis.

Background

The foldable device design is adopted, so that a large screen can be used, and the device can be placed in a pocket. However, foldable displays may suffer from the problem of visible bending area bumps at the hinge. Such bumps are formed when using a polymer as the cover material, which distorts the pixels and the image, thereby affecting the viewing experience of the user.

One of the current solutions is to use only polymers, i.e. no glass material. This solution ensures that sufficient bending and folding can be performed even with a relatively small bending radius. However, the polymer will creep after a long period of bending, so that the hinge area will see folds when the device is unfolded. Furthermore, scratch resistant surfaces are difficult to achieve because of the challenges of using hard coatings on softer polymers themselves and because the use of soft self-healing coatings gives different feel to the surface.

Another approach is to use ultra thin glass (e.g. only 30 μm thick). The thin film of ultra-thin glass is flexible enough to bend to the desired radius. However, such thin, hard glass films are extremely fragile and can be pierced with minimal effort, resulting in glass breakage. When chemically strengthening glass, the strengthening layer is at most only a few μm thick due to the force balance, which is insufficient to provide adequate protection for the film.

In addition, attempts have been made to reduce the thickness of the hinge region glass so as to be able to bend to a small radius. However, since the thin and hard glass film is extremely fragile as described above, this makes the bending region very likely to break.

Accordingly, there is a need to provide an improved display assembly suitable for use in curved, folded and sliding displays.

Disclosure of Invention

It is an object of the present invention to provide an improved display assembly. The above and other objects are achieved by the features of the independent claims. Other implementations are apparent in the dependent claims, the description and the drawings.

According to a first aspect, there is provided a display assembly for an electronic device, comprising: a flexible display structure configured to bend around a main axis; a substrate overlying the flexible display structure and comprising a first material; wherein the matrix comprises a grating structure disposed adjacent to the principal axis of the flexible structure, wherein the grating structure comprises a second material having a lower density than the first material.

By reducing the young's modulus in a portion of the matrix, i.e. the tensile stiffness in said portion, the matrix becomes more flexible only in said portion. This enables the display assembly to flex while providing a relatively thicker matrix, the thicker the matrix the greater its impact resistance. Furthermore, by reducing the stiffness in the hinge area of the electronic device, this reduces the risk of delamination of the display component layers. In addition, the substrate may form a scratch-resistant cover structure.

In a possible implementation of the first aspect, the grating structure extends through a middle portion of the matrix, the portion being configured to be disposed adjacent to the main axis of the flexible display structure when the flexible display structure is bent. By altering the internal mechanical properties of a portion of the substrate, which is less dense and therefore more flexible, the substrate can bend at that portion while still retaining its original properties, namely scratch and impact resistance on the surface of the substrate, etc.

In another possible implementation of the first aspect, the grating structure is subjected to a tensile stress when the flexible display structure is bent, the grating structure facilitating bending of the display assembly in a tensile stress region.

In another possible implementation of the first aspect, the flexible display structure is configured to bend around the main axis by: bending around the main axis, folding around the main axis or/and sliding across the main axis in a direction perpendicular to the main axis facilitates implementation of solutions that can be applied to different bending structures.

In another possible implementation of the first aspect, the first material comprises aluminosilicate glass and/or fused silica glass. Such a solution allows for a display assembly that can be bent without eventually forming visible bumps in the bending area.

In another possible implementation of the first aspect, the first material comprises a multicomponent glass.

In another possible implementation of the first aspect, the second material comprises air, so as to facilitate implementation of a simple solution that is as light as possible.

In another possible implementation of the first aspect, the grating structure is formed by a plurality of elongated channels, each channel comprising a plurality of nanostructures, allowing the grating structure to penetrate a large amount of material, and the properties of the grating structure, and thus the matrix, vary within the grating structure.

In another possible implementation of the first aspect, the channels are periodically arranged in the portion such that central axes of the channels extend in parallel and each channel is separated from adjacent channels by the first material while providing stability and flexibility.

In another possible implementation of the first aspect, each elongated channel extends along a central axis that extends perpendicular or parallel to the main axis, thereby simplifying manufacturing while still providing the required flexibility.

In another possible implementation manner of the first aspect, the plurality of nanostructures of the channel are grooves formed on a surface of the channel, the nanostructures being disposed along the central axis of the channel.

In another possible implementation of the first aspect, the nanostructures of the channels extend at an angle to a central axis of the channels, allowing the characteristics of the grating structure to be adapted to a specific structure.

In another possible implementation of the first aspect, the plurality of nanostructures of the channel extend at least partially around an inner circumference of the channel and extend at an angle to the central axis of the channel, the angle being greater than 0 °.

In another possible implementation of the first aspect, at least a first central axis of a first channel extends parallel to a second central axis of a second channel, and the nanostructures of the first channel extend to the central axis at a different angle than the nanostructures of the second channel, allowing a variation of the properties of the grating structure and thus of the matrix within the grating structure.

According to a second aspect, there is provided an electronic device comprising: a first housing portion, a second housing portion, and a display assembly according to the above, wherein at least a first portion of the display assembly is connected to the first housing portion, a second portion of the display assembly is connected to the second housing portion, and an intermediate portion of the display assembly is configured to flex about a main axis when the second housing portion moves relative to the first housing portion.

By reducing the young's modulus in a portion of the display assembly, i.e. reducing the tensile stiffness in said portion, the display assembly becomes more flexible only in said portion. This allows the display assembly to flex while still being impact resistant. Furthermore, by reducing the stiffness in the hinge area of the electronic device, this reduces the risk of delamination of the display component layers.

In a possible implementation of the second aspect, the movement of the second housing part comprises the second housing part pivoting about the main axis relative to the first housing part or the second housing part sliding relative to the first housing part in a direction perpendicular to the main axis, allowing the solution to be applied to different device configurations.

According to a third aspect, there is provided a method of manufacturing a display assembly, the method comprising the steps of: providing a matrix comprising a first material; writing a grating structure through a portion of the substrate using femtosecond laser machining; the matrix is applied to a flexible display structure configured to bend around a principal axis such that the grating structure is disposed adjacent to the principal axis of the flexible display structure.

In a possible implementation of the third aspect, the method further comprises a final step of applying a coating to the substrate, providing further protection for the substrate and the display assembly.

These and other aspects will become apparent from one or more embodiments described below.

Drawings

In the following detailed description of the invention, aspects, embodiments and implementations will be described in more detail in connection with exemplary embodiments illustrated in the accompanying drawings, in which:

FIG. 1 shows a schematic top view of an electronic device provided by an example of an embodiment of the invention;

FIG. 2 illustrates a schematic side view of a display assembly provided by an example of an embodiment of the present invention;

FIG. 3 illustrates a schematic diagram of a grating structure of a display assembly provided by an example of an embodiment of the present invention;

fig. 4a and 4b show schematic diagrams of a grating structure with nanostructures provided by examples of embodiments of the invention.

Detailed Description

Fig. 1 shows an electronic device 2 comprising a first housing part 7a, a second housing part 7b and a display assembly 1 described in more detail below, wherein at least a first part of the display assembly 1 is connected to the first housing part 7a and a second part of the display assembly 1 is connected to the second housing part 7b, the middle part of the display assembly 1 being configured to bend around a main axis A1 when the second housing part 7b is moved or has been moved relative to the first housing part 7 a.

The movement of the second housing portion 7b may include the second housing portion 7b pivoting relative to the first housing portion 7a about the spindle A1 such that the electronic device 2 is foldable and expandable between a smartphone and a tablet computer, or the like. The second housing part 7b may also be arranged to slide relative to the first housing part 7a in a direction D1, D2 perpendicular to the main axis A1, such that the electronic device 2 is inflated, for example by sliding the second housing part 7b out of the first housing part 7 a.

A display assembly 1 for an electronic device 2, comprising: a flexible display structure 3 configured to be bent around a main axis A1; a substrate 5 superimposed on the flexible display structure 3 and comprising a first material; wherein the matrix 5 comprises a grating structure 6 arranged adjacent to the main axis A1 of the flexible structure 3, wherein the grating structure 6 comprises a second material having a lower density than the first material.

Fig. 2 schematically shows a display assembly 1. The display assembly 1 comprises a flexible display structure 3 configured to bend around a main axis A1. The flexible display structure 3 may comprise any suitable and desired number of layers, such as a touch screen, polarizer, diffuser, color filter or adhesive layer.

The flexible display structure 3 may be configured to bend around the main axis A1 by: bending around the main axis A1, folding around the main axis A1, or/and sliding across the main axis A1 in directions D1, D2 perpendicular to the main axis A1. The flexible display structure 3 may, for example, be configured to bend simultaneously around the spindle A1 and slide vertically across the spindle A1, depending on the structure of the electronic device 2.

The display assembly 1 further comprises a substrate 5 which is superimposed on the flexible display structure 3. When a portion of the flexible display structure 3 is bent, the matrix 5 is also bent. The matrix 5 is configured to form a cover structure 4 overlying the display structure 3 to prevent scratching and impact.

The matrix 5 comprises a first material. The first material may comprise aluminosilicate glass, fused silica glass, or any suitable transparent multicomponent glass. The first material may be chemically strengthened.

The matrix 5 further comprises a grating structure 6 arranged adjacent to the main axis A1 of the flexible structure 3, i.e. the grating structure 6 extends through the volume of the matrix 5 which may be bent at a certain point. For example, the edges of the substrate 5 disposed along the opposite long sides of the first housing portion 7a and the second housing portion 7b are likely not to bend, regardless of the position of the electronic device 2.

In other words, as shown in fig. 1 and 2, the grating structure 6 may extend through a middle portion 5a of the substrate 5, which portion 5a is configured to be disposed adjacent to the main axis A1 of the flexible display structure 3 when the flexible display structure 3 is bent. The portion 5a may be a volume that extends partially through the substrate 5 in a direction D1, D2 perpendicular to the main axis A1 and partially through the substrate 5 in a direction D3, D4 perpendicular to the directions D1, D2 and the main axis A1. For example, when the total thickness of the substrate 5 is 70 μm, the top and bottom layers of the substrate 5 having a thickness of 10 μm as seen in the direction D3, D4 may be devoid of the grating structure 6, such that the thickness of the portion 5a is 50 μm.

When the electronic device 2 has a foldable structure, the portion 5a is typically a specific volume that is not changed or moved, i.e. is always located at the same position. When the electronic device 2 has a sliding structure, the portion 5a is movable to some extent, as the size of the electronic device 2 expands or reduces, the display assembly 1 slides over the spindle A1, and thus the portion 5a also moves relative to the spindle A1. In other words, the portion 5a may be a portion subjected to tensile stress when the flexible display structure 3 is bent. More specifically, the grating structure 6 may be subjected to tensile stress when the flexible display structure 3 is bent.

The grating structure 6 comprises a second material having a lower density than the first material. The second material may comprise air, i.e. such that the grating structure 6 is a hollow structure. However, the grating structure 6 may be filled with any suitable material.

As schematically shown in fig. 3, the grating structure 6 may be formed by a plurality of elongated channels 6 a. The channel 6a may have an oval cross-section, however any suitable technically achievable cross-section is possible.

The channels 6a may be periodically arranged in the portion 5a such that each channel 6a is separated from adjacent channels 6a by said first material. Each elongate channel 6a may extend along a central axis A2, as shown in fig. 4a and 4b, the central axis A2 extending perpendicular or parallel to the main axis A1. However, the layout of the channels 6a depends on several factors, such as the actual substrate thickness, substrate chemistry, radius of curvature required and manufacturing process parameters selected.

As schematically shown in fig. 4a and 4b, each channel 6a may comprise a plurality of nanostructures 6b, i.e. nanograms. Each nanostructure 6b forms a groove on the inner surface of the channel 6, such that a plurality of nanostructures 6b form periodic grooves having a nanoscale dimension, i.e. the width of the nanostructure 6b is significantly smaller than the width of the channel 6 a. The nanostructures 6b form grooves which may extend at an angle alpha to the central axis A2 of the channel, as shown in fig. 4 a. In one embodiment, the plurality of nanostructures 6b extend at least partially around the inner circumference of the channel 6a and extend at an angle to the central axis A2 of the channel 6a, the angle being greater than 0 °.

The nanostructures 6b form any suitable texture pattern or corrugation on the surface of the channels 6 a. The nanostructure 6b comprises the same material as the channel 6a, i.e. the second material. In other words, the channels 6a and the nanostructures 6b may be formed in the first material (e.g., aluminosilicate glass) such that the channels 6a and the nanostructures 6b together form an air-filled hollow structure. The actual structure of the nanostructure depends on the interaction between the glass material (i.e. the first material) and the laser used to form the grating structure 6. In addition, the size, direction, and angle may vary with laser power, processing speed, and optical characteristics.

At least a first central axis A2 of the first channel 6a extends parallel to a second central axis A2 of the second channel, and the nanostructures 6b of the first channel 6a extend at different angles to the nanostructures 6b of said second channel, as shown in fig. 4a and 4 b. The channels 6a may be arranged such that each second channel 6a has a first set of nanostructures 6b, while the other channels 6a have a second set of nanostructures 6b. However, any number of sets of different nanostructures 6b is possible.

The invention also relates to a method of manufacturing a display assembly 1, the method comprising the steps of: providing a matrix 5 comprising a first material; the grating structure 6 is written by a part of the substrate 5 using a femtosecond laser machining. Femtosecond laser machining allows the use of light to create the smallest structures possible. The channel 6a (i.e. the laser track) can be written in an optimal direction compared to the bending of the display assembly 1 and the polarization of the laser beam can also be optimized to form the nanostructures 6b at an angle that results in a maximum change in young's modulus (e.g. from 75GPa to 36 GPa). For each type of matrix 5 material, the laser parameters that can provide the best results, such as energy, pulse duration, translation speed and polarization, must be determined. For example, the laser writing parameters may be 50fs, 250nJ, 120kHz, 1mm/s, polarized 90 in the writing direction.

Subsequently, the matrix 5 is applied to the flexible display structure 3 configured to bend around the main axis A1 such that the grating structure 6 is arranged adjacent to the main axis A1 of the flexible display structure 3. The method may further comprise a final step of applying a coating 8, preferably a hard coating, to the substrate 5.

Aspects and implementations have been described herein in connection with various embodiments. However, other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed subject matter, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the "a" or "an" does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

Reference signs used in the claims shall not be construed as limiting the scope. Unless otherwise indicated, the drawings (e.g., cross-hatching, arrangement of parts, proportion, degree, etc.) should be read together with the specification, and should be considered a portion of the entire written description of this invention. The terms "horizontal," "vertical," "left," "right," "upper" and "lower," as well as adjectives and adverb derivatives thereof (e.g., "horizontally," "rightward," "upward," etc.) as used in the specification, simply refer to the direction of the structure as shown when the particular drawing figure is oriented toward the reader. Similarly, the terms "inwardly" and "outwardly" generally refer to the direction of a surface relative to its axis of elongation or axis of rotation (as the case may be).

Claims

1. A display assembly (1) for an electronic device (2), comprising:

a flexible display structure (3) configured to bend around a main axis (A1);

a substrate (5) superimposed on said flexible display structure (3) and comprising a first material;

wherein the matrix (5) comprises a grating structure (6) arranged adjacent to the main axis (A1) of the flexible structure (3), wherein the grating structure (6) comprises a second material having a lower density than the first material.

2. The display assembly (1) according to claim 1, wherein the grating structure (6) extends through an intermediate portion (5 a) of the matrix (5), the intermediate portion (5 a) being at least partially arranged adjacent to the main axis (A1) of the flexible display structure (3).

3. A display assembly (1) according to claim 1 or 2, characterized in that the grating structure (6) is subjected to tensile stress when the flexible display structure (3) is bent.

4. The display assembly (1) according to any of the preceding claims, wherein the flexible display structure (3) is configured to bend around the main axis (A1) by: bending around the main axis (A1), folding around the main axis (A1) or/and sliding across the main axis (A1) in a direction (D1, D2) perpendicular to the main axis (A1).

5. A display assembly (1) according to any of the preceding claims, wherein the first material comprises aluminosilicate glass and/or fused silica glass.

6. A display assembly (1) according to any of the preceding claims, wherein the second material comprises air.

7. The display assembly (1) according to any of the preceding claims, wherein the grating structure (6) is formed by a plurality of elongated channels (6 a), each channel (6 a) comprising a plurality of nanostructures (6 b).

8. The display assembly (1) according to claim 7, wherein the channels (6 a) are periodically arranged in the portion (5 a) such that the central axes (A2) of the channels (6 a) extend in parallel and each channel (6 a) is separated from an adjacent channel (6 a) by the first material.

9. The display assembly (1) according to claim 7 or 8, wherein the plurality of nanostructures (6 b) of the channel (6 a) are grooves formed on a surface of the channel (6 a), the nanostructures (6 b) being arranged along the central axis (A2) of the channel (6 a).

10. The display assembly (1) according to claim 9, wherein the plurality of nanostructures (6 b) of the channel (6 a) extends at least partially around an inner circumference of the channel (6 a) and extends at an angle (a) to the central axis (A2) of the channel (6 a), the angle being greater than 0 °.

11. The display assembly (1) according to claim 9 or 10, characterized in that at least a first central axis (A2) of a first channel (6 a) extends parallel to a second central axis (A2) of a second channel, and that the nanostructures (6 b) of the first channel (6 a) extend to the central axis (A2) at a different angle (a) to the nanostructures (6 b) of the second channel.

12. An electronic device (2), characterized by comprising: a first housing part (7 a), a second housing part (7 b) and a display assembly (1) according to any one of claims 1 to 10, wherein at least a first part of the display assembly (1) is connected to the first housing part (7 a), a second part of the display assembly (1) is connected to the second housing part (7 b), an intermediate part of the display assembly (1) being configured to bend around a main axis (A1) when the second housing part (7 b) is moved relative to the first housing part (7 a).

13. The electronic device (2) according to claim 12, characterized in that the movement of the second housing part (7 b) comprises pivoting the second housing part (7 b) relative to the first housing part (7 a) about the main axis (A1) or sliding the second housing part (7 b) relative to the first housing part (7 a) in a direction (D1, D2) perpendicular to the main axis (A1).

14. A method of manufacturing a display assembly (1), the method comprising the steps of:

providing a matrix (5) comprising a first material;

writing a grating structure (6) through a portion of the substrate (5) using femtosecond laser machining;

-applying the matrix (5) to a flexible display structure (3) configured to bend around a main axis (A1) such that the grating structure (6) is arranged adjacent to the main axis (A1) of the flexible display structure (3).

15. The method according to claim 14, further comprising a final step of applying a coating (8) onto the substrate (5).