The display apparatus further includes a bending portion PBP and a connecting portion CP. The connecting portion CP is a portion where a flexible printed circuit can be bonded to the display apparatus. The bending portion PBP is flexible or bendable. As shown in FIG. 1, the bending portion PBP may be bent along the direction of an arrow depicted in FIG. 1 so that the connecting portion CP can be bent toward a back side of the display portion. FIG. 2 is a schematic diagram of a display apparatus in some embodiments according to the present disclosure. FIG. 2 depicts a display apparatus in which the bending portion PBP is bent, and the connecting portion CP is bent toward the back side of the display portion.

FIG. 3 is a plan view of a display apparatus in some embodiments according to the present disclosure. Referring to FIG. 3, the display portion DP in some embodiments is in a display region DR in which an image is displayed and a fanout region FR between the display region DR and the bending portion PBP, the display portion DP including a plurality of signal lines SL extending through the fanout region FR.

As used herein, the term “display region” refers to a region of a display panel in a display apparatus where image is actually displayed. Optionally, the display region may include both a subpixel region and an inter-subpixel region. A subpixel region refers to a light emission region of a subpixel, such as a region corresponding to a pixel electrode in a liquid crystal display or a region corresponding to a light emissive layer in an organic light emitting diode display panel. An inter-subpixel region refers to a region between adjacent subpixel regions, such as a region corresponding to a black matrix in a liquid crystal display or a region corresponding a pixel definition layer in an organic light emitting diode display panel. Optionally, the inter-subpixel region is a region between adjacent subpixel regions in a same pixel. Optionally, the inter-subpixel region is a region between two adjacent subpixel regions from two adjacent pixels. Optionally, the display apparatus is a flexible display apparatus.

FIG. 4A is a cross-sectional view around a bending portion of a display apparatus in some embodiments according to the present disclosure. Referring to FIG. 4A, in some embodiments, the display apparatus includes a display portion DP; a polarizer PL on a first side S1 of the display portion DP; a cover window CF on the first side S1 of the display portion DP, and on a side of the polarizer PL away from the display portion DP; a connecting portion CP; a bending portion PBP connecting the display portion DP and the connecting portion CP. The bending portion PBP is bent so that the connecting portion CP is facing a second side S2 of the display portion DP, forming a bending cavity Cpb that is surrounded by the bending portion PBP. As shown in FIG. 4A, the second side S2 is opposite to the first side S1.

In some embodiment, the display apparatus further includes a coating layer MCL covering a back side SDB of the bending portion PBP opposite to a side SDPS directly surrounding the bending cavity Cpb. In one example, the back side SDB of the bending portion PBP is a side of the bending portion PBP that is in direct contact with the coating layer MCL, and the side SDPS directly surrounding the bending cavity Cpb is a side of the bending portion PBP that is not in contact with the coating layer MCL. The coating layer MCL includes a main portion Pm, and a tapered portion Pt extending from the main portion Pm toward the polarizer PL. For example, the tapered portion Pt extends from the main portion Pm onto the first side S1 of the display portion DP, an edge of the tapered portion Pt adjacent to the polarizer PL is spaced apart from the polarizer PL. In one example, the tapered portion Pt covers a portion of the fanout region FR in the display portion DP.

In some embodiments, the coating layer MCL further includes an additional tapered portion Pat, extending from the main portion Pm onto a side of the connecting portion CP opposite to the display portion DP.

FIG. 4B is a partial view around a tapered portion of a coating layer in a display apparatus in some embodiments according to the present disclosure. FIG. 4C is a partial plan view around a tapered portion of a coating layer in a display apparatus in some embodiments according to the present disclosure. Referring to FIG. 4B and FIG. 4C, in some embodiments, a height h of the tapered portion Pt, relative to a main surface Sm of the display portion DP on the first side S1, gradually increases from an edge Ept of the tapered portion Pt adjacent to the polarizer PL to a boundary B1 between the tapered portion Pt and the main portion Pm. Optionally, the boundary B1 is a boundary at which the tapered portion Pt has a maximum height relative to the main surface Sm of the display portion DP on the first side S1. Optionally, the boundary B1 is a boundary that is co-planar with an edge of the first back film BF1 proximal to the bending cavity Cpb.

Referring to FIG. 4A to FIG. 4C, in some embodiments, an orthographic projection of the cover window CF on the plane comprising the main surface Sm of the display portion DP is between an orthographic projection of the edge Ept of the tapered portion Pt adjacent to the polarizer PL on the plane comprising the main surface Sm of the display portion DP and an orthographic projection of the boundary B1 between the tapered portion Pt and the main portion Pm on the plane comprising the main surface Sm of the display portion DP. Optionally, a first shortest distance Ds1 between an orthographic projection of an edge Epl of the polarizer PL adjacent to the tapered portion Pt on the plane comprising the main surface Sm of the display portion DP and the orthographic projection of the edge Ept of the tapered portion Pt adjacent to the polarizer PL on the plane comprising the main surface Sm of the display portion DP is equal to or greater than a first value. Optionally, a second shortest distance Ds2 between an orthographic projection of an edge Ecf of the cover window adjacent to the tapered portion Pt on the plane comprising the main surface Sm of the display portion DP and the orthographic projection of the boundary B1 between the tapered portion Pt and the main portion Pm on the plane comprising the main surface Sm of the display portion DP is also equal to or greater than the first value.

Optionally, the first value is equal to an engineering tolerance of the tapered portion Pt. Optionally, the engineering tolerance of the tapered portion Pt is in a range of 150 μm to 250 μm, e.g., 150 μm to 175 μm, 175 μm to 200 μm, 200 μm to 225 μm, or 225 μm to 250 μm. Optionally, the first value is in a range of 150 μm to 250 μm, e.g., 150 μm to 175 μm, 175 μm to 200 μm, 200 μm to 225 μm, or 225 μm to 250 μm. Optionally, the engineering tolerance of the tapered portion Pt is 200 μm. Optionally, the first value is 200 μm. Optionally, the first shortest distance Ds1 is equal to or greater than 200 μm. Optionally, the second shortest distance Ds2 is equal to or greater than 200 μm. As used herein, the term “engineering tolerance” refers to a tolerance for an error or a range of error in forming a part of the display apparatus such as the tapered portion Pt.

In some embodiments, the display apparatus further includes an optically clear adhesive layer OCA on the first side S1 of the display portion DP. The optically clear adhesive layer OCA is between the polarizer PL and the cover window CF. The optically clear adhesive layer OCA attaches the cover window SF to the polarizer PL. Referring to FIG. 4B, the optically clear adhesive layer in some embodiments has a first adhering surface Sa1 at least partially attaching to the cover window SF, a second adhering surface Sa2 at least partially attaching to the polarizer PL, and an edge Eoca connecting the first adhering surface Sa1 and the second adhering surface Sa2. The edge Eoca is adjacent to the tapered portion Pt. Referring to FIG. 4A to FIG. 4C, an orthographic projection of the edge Eoca connecting the first adhering surface Sa1 and the second adhering surface Sa2 on the plane comprising the main surface Sm of the display portion DP is between the orthographic projection of the edge Epl of the polarizer PL adjacent to the tapered portion Pt on the plane comprising the main surface Sm of the display portion DP and the orthographic projection of the edge Ecf of the cover window CF adjacent to the tapered portion Pt on the plane comprising the main surface Sm of the display portion DP.

Optionally, the orthographic projection of the edge Eoca connecting the first adhering surface Sa1 and the second adhering surface Sa2 on the plane comprising the main surface Sm of the display portion DP is between an orthographic projection of the edge Ept of the tapered portion Pt adjacent to the polarizer PL on the plane comprising the main surface Sm of the display portion DP and an orthographic projection of the boundary B1 between the tapered portion Pt and the main portion Pm on the plane comprising the main surface Sm of the display portion DP.

In some embodiments, a third shortest distance Ds3, between the orthographic projection of the edge Eoca connecting the first adhering surface Sa1 and the second adhering surface Sa2 on the plane comprising the main surface Sm of the display portion DP and an orthographic projection of a virtual contour line Lvc on a surface of the tapered portion Pt on the plane comprising the main surface Sm of the display portion DP, is also equal to or greater than the first value. Referring to FIG. 4B, the virtual contour line Lvc in some embodiments is defined as follows: a height h1 of the virtual contour line Lvc, relative to the main surface Sm of the display portion DP on the first side S1, equals to a height h2 of the second adhering surface Sa2, relative to the main surface Sm of the display portion DP on the first side S1.

Optionally, the first value is equal to an engineering tolerance of the tapered portion Pt. Optionally, the engineering tolerance of the tapered portion Pt is in a range of 150 μm to 250 μm, e.g., 150 μm to 175 μm, 175 μm to 200 μm, 200 μm to 225 μm, or 225 μm to 250 μm. Optionally, the first value is in a range of 150 μm to 250 μm, e.g., 150 μm to 175 μm, 175 μm to 200 μm, 200 μm to 225 μm, or 225 μm to 250 μm. Optionally, the engineering tolerance of the tapered portion Pt is 200 μm. Optionally, the first value is 200 μm. Optionally, the third shortest distance Ds3 is equal to or greater than 200 μm.

In some embodiments, a fourth shortest distance Ds4 between the orthographic projection of the edge Eoca connecting the first adhering surface Sa1 and the second adhering surface Sa2 on the plane comprising the main surface Sm of the display portion DP and the orthographic projection of the edge Ecf of the cover window CF adjacent to the tapered portion Pt on the plane comprising the main surface Sm of the display portion DP is equal to or greater than a second value.

Optionally, the second value is equal to a bonding tolerance of the optically clear adhesive layer OCA. Optionally, the bonding tolerance of the optically clear adhesive layer is in a range of 100 μm to 200 μm, e.g., 100 μm to 125 μm, 125 μm to 150 μm, 150 μm to 175 μm, or 175 μm to 200 μm. Optionally, the second value is in a range of 100 μm to 200 μm, e.g., 100 μm to 125 μm, 125 μm to 150 μm, 150 μm to 175 μm, or 175 μm to 200 μm. Optionally, the bonding tolerance of the optically clear adhesive layer OCA is 150 μm. Optionally, the second value is 150 μm. Optionally, the fourth shortest distance Ds4 is equal to or greater than 150 μm. As used herein, the term “bonding tolerance” refers to a tolerance for an error or a range of error in bonding two parts of the display apparatus, for example, in bonding the optically clear adhesive layer OCA, e.g., to the cover window CF or to the polarizer PL. The error may be due to an alignment error in bonding the optically clear adhesive layer OCA with another part.

In some embodiments, and referring to FIG. 4A to FIG. 4C, the orthographic projection of the edge Ept of the tapered portion Pt adjacent to the polarizer PL on the plane comprising the main surface Sm of the display portion DP is between the orthographic projection of the edge Epl of the polarizer PL adjacent to the tapered portion Pt on the plane comprising the main surface Sm of the display portion DP and the orthographic projection of the edge Eoca connecting the first adhering surface Sa1 and the second adhering surface Sa2 on the plane comprising the main surface Sm of the display portion DP. The orthographic projection of the edge Ept of the tapered portion Pt adjacent to the polarizer PL on the plane comprising the main surface Sm of the display portion DP is spaced apart from the orthographic projection of the edge Epl of the polarizer PL adjacent to the tapered portion Pt on the plane comprising the main surface Sm of the display portion DP by a first spaced-apart distance d1 greater than zero, and is spaced apart from the orthographic projection of the edge Eoca connecting the first adhering surface Sa1 and the second adhering surface Sa2 on the plane comprising the main surface Sm of the display portion DP by a second spaced-apart distance d2 greater than zero. The orthographic projection of the edge Epl of the polarizer PL adjacent to the tapered portion Pt on the plane comprising the main surface Sm of the display portion DP and the orthographic projection of the edge Eoca connecting the first adhering surface Sa1 and the second adhering surface Sa2 on the plane comprising the main surface Sm of the display portion DP are spaced apart from each other by a sum of the first spaced-apart distance d1 and the second spaced-apart distance d2.

In addition, a position of the edge Epl of the polarizer PL adjacent to the tapered portion Pt may be carefully determined to prevent light leakage on the peripheral region of the display apparatus.

In some embodiments, the connecting portion CP and the display portion DP are parts of a stacked structure in the display apparatus. Referring to FIG. 4A, the display portion DP may be used as a reference for describing the structure of the stacked structure. On the first side S1 (a light emitting image display side) of the display portion DP, the stacked structure in some embodiments includes one or more of a polarizer PL on the display portion DP; an optically clear adhesive layer OCA on a side of the polarizer PL away from the display portion DP; and a cover window CF on a side of the optically clear adhesive layer OCA away from the polarizer PL. The optically clear adhesive layer OCA attaches the cover window CF to the polarizer. On a second side S2 (a back side) of the display portion DP, the stacked structure in some embodiments includes one or more of a first back film BF1 on a back surface Sb of the display portion DP on the second side S2, a support layer SL (e.g., a metal support layer) on a side of the second back film BF1 away from the display portion DP; a metal plate MP on a side of the support layer SL away from the second back film BF2; a second back film BF2 on a side of the metal plate MP away from the support layer SL; and the connecting portion CP on a side of the second back film BF2 away from the metal plate MP.

FIG. 4D is a plan view of a support layer, a first back film, and a metal plate in some embodiments according to the present disclosure. Referring to FIG. 4A to FIG. 4D, in some embodiments, an orthographic projection of the support layer SL on the display portion DP substantially overlaps with an orthographic projection of the first back film BF1 on the display portion DP. Optionally, an orthographic projection of an edge Esl of the support layer SL on the display portion DP substantially overlaps with an orthographic projection of an edge Ebf1 of the first back film BF1 on the display portion DP. Optionally, an orthographic projection of the first back film BF1 on the display portion DP covers an orthographic projection of the metal plate MP on the display portion DP with a margin. Optionally, an orthographic projection of the support layer SL on the display portion DP covers an orthographic projection of the metal plate MP on the display portion DP with a margin.

FIG. 4E is a partial view around a tapered portion of a coating layer in a display apparatus in some embodiments according to the present disclosure. Referring to FIG. 4E, in some embodiments, the edge Eoca connecting the first adhering surface Sa1 and the second adhering surface Sa2 is not a vertical edge (e.g., not an edge perpendicular to the first adhering surface Sa1 or the second adhering surface Sa2), but rather an edge having an acute slope angle with respect to the first adhering surface Sa1. Accordingly, the edge Eoca comprises a first edge Eo1 at the interface with the first adhering surface Sa1 and a second edge Eo2 at the interface with the second adhering surface Sa2. Optionally, “an orthographic projection of the edge Eoca connecting the first adhering surface Sa1 and the second adhering surface Sa2” refers to an orthographic projection of the second edge Eo2.

FIG. 5 is a cross-sectional view around a bending portion of a display apparatus in some embodiments according to the present disclosure. Referring to FIG. 5, the display apparatus in some embodiments further includes a bezel BZ covering the coating layer MCL. The bezel BZ is on a side of the coating layer MCL away from the bending portion PBP. Optionally, the bezel BZ is connected to the cover window CF. Optionally, the bezel BZ is made of a relatively rigid material.

FIG. 6 is a cross-sectional view around a bending portion of a display apparatus in some embodiments according to the present disclosure. Referring to FIG. 6, the display apparatus in some embodiments includes a display portion DP; a connecting portion CP; a bending portion PBP connecting the display portion DP and the connecting portion CP; a first back film BF1 covering a surface of the display portion DP facing the connecting portion CP; a second back film BF2 covering a surface of the connecting portion CP facing the display portion DP; a support layer SL and a metal plate MP between the first back film BF1 and the second back film BF2. The support layer SL is between the metal plate MP and the first back film BF1. The metal plate MP is between the support layer SL and the second back film BF2. As discussed above, the display apparatus in some embodiments includes a bending cavity Cpb that is surrounded by the bending portion PBP. The bending portion PBP is absent of any back film, e.g., the first back film BF1 and the second back film BF2 are absent in the region having the bending portion PBP. In one example, the cover window CF has a thickness 83±5 μm, the optically clear adhesive layer OCA has a thickness of 50±5 μm, the polarizer PL has a thickness of 55±5 μm, the coating layer MCL has a thickness of 90±30 μm. In principle, a sum of the thickness of the optically clear adhesive layer OCA and the thickness of the polarizer PL is equal to or greater than the thickness of the coating layer MCL. The inventors in the present disclosure discover that, when the thickness of the coating layer MCL reaches the maximum value (e.g., 120 μm), the thickness of the coating layer MCL becomes greater than the sum of the thickness of the optically clear adhesive layer OCA and the thickness of the polarizer PL. As shown in FIG. 6, a first interference region Ri1 is formed in which the cover window CF and the coating layer MCL interfere with each other, resulting either a bulge in the cover window CF or an excessive force on the bending portion PBP.

Accordingly, the inventors of the present disclosure have developed an intricate structure to eliminate the interference in the present display apparatus as exemplified in FIG. 4A to FIG. 4C by defining critical parameters including at least one of the first shortest distance Ds1, the second shortest distance Ds2, the third shortest distance Ds3, or the fourth shortest distance Ds4. In the present display apparatus, not only the interference between the cover window CF and the coating layer MCL can be eliminated, but also other defects such as cover window depression, bending portion cracking, and light leakage, can be effectively prevented or entirely eliminated.

FIG. 7 is a cross-sectional view around a bending portion of a display apparatus in some embodiments according to the present disclosure. Referring to FIG. 7, to ensure that signal lines in the bending portion PBP is not subject to stress or a reduced stress, a coating layer MCL is formed on the outer surface of the bending portion PBP to change the position of a neutral plane NP in the bending region. On the other hand, to enhance the flexibility of the bending portion PBP, back film is removed from the bending portion. For example, the bending portion PBP is absent of any back film, e.g., the first back film BF1 and the second back film BF2 are absent in the region having the bending portion PBP. In the fanout region FR, however, the first back film BF1 is maintained to protect the signal lines therein. The inventors of the present disclosure discover that, due to various engineering tolerances (e.g., a material tolerance of the first back film BF1, a bonding tolerance of the first back film BF1, a bending tolerance of the bending portion PBP, a flow tolerance of the coating layer MCL, and an overlength of the neutral plane NP), the back film (such as the first back film BF1) and the bending portion PBP could interfere with each other. As shown in FIG. 7, a second interference region Ri2 is formed in which the first back film BF1 and the bending portion PBP interfere with each other, resulting an excessive force on the bending portion PBP. As used herein, the term “material tolerance” refers to a tolerance for an error or a range of error introduced by a material forming a part of the display apparatus, e.g., a material forming the first back film BF1. As used herein, the term “bonding tolerance” refers to a tolerance for an error or a range of error in bonding two parts of the display apparatus, for example, in bonding the first back film BF1, e.g., to the display portion DP. The error may be due to an alignment error in bonding the first back film BF1 with another part. As used herein, the term “bending tolerance” refers to a tolerance for an error or a range of error in in bending a part or parts of the display apparatus, for example, in bending the bending portion PBP. As used herein, the term “flow tolerance” refers to a tolerance for an error or a range of error in forming a part of the display apparatus due to the fact that a material forming the part is not completely solid and is prone to flow. As used herein, the term “overlength of the neutral plane” denotes a change (e.g., a difference, or an increase) in a length of a neutral plane as a result of the change of the position of a neutral plane NP in the bending region upon forming the coating layer MCL on the outer surface of the pad pending portion PBP.

To prevent this issue, the inventors of the present disclosure have further improved the structure of the display apparatus. FIG. 8A is a cross-sectional view around a bending portion of a display apparatus in some embodiments according to the present disclosure. FIG. 8B is a partial view around a tapered portion of a coating layer in a display apparatus in some embodiments according to the present disclosure. FIG. 8C is a partial plan view around a tapered portion of a coating layer in a display apparatus in some embodiments according to the present disclosure. Referring to FIG. 8A to FIG. 8C, in some embodiments, an orthographic projection of an edge Ebf1 of the first back film BF1 adjacent to the bending portion PBP on the plane comprising the main surface Sm of the display portion DP is between an orthographic projection of a boundary B2 between the fanout region FR and the bending portion PBP on the plane comprising the main surface Sm of the display portion DP and an orthographic projection of a bending line BL, along which the bending portion PBP is bent, on the plane comprising the main surface Sm of the display portion DP. Moreover, the orthographic projection of the edge Ebf1 of the first back film BF1 adjacent to the bending portion PBP on the plane comprising the main surface Sm of the display portion DP is also between the orthographic projection of the boundary B1 between the tapered portion PT and the main portion Pm on the plane comprising the main surface Sm of the display portion DP and an orthographic projection of a bending line BL, along which the bending portion PBP is bent, on the plane comprising the main surface Sm of the display portion DP.

In some embodiments, referring to FIG. 8A to FIG. 8C, a fifth shortest distance Ds5 between the orthographic projection of the edge Ebf1 of the first back film BF1 adjacent to the bending portion PBP on the plane comprising the main surface Sm of the display portion DP and the orthographic projection of the bending line BL on the plane comprising the main surface Sm of the display portion DP is equal to or greater than a third value.

In some embodiments, the third value can be expressed as √{square root over (a²+b²)}; wherein a is a bonding tolerance of the first back film BF1; and b is a bending tolerance of the bending portion PBP. Optionally, the bonding tolerance of the first back film BF1 is in a range of 50 μm to 150 μm, e.g., 50 μm to 75 μm, 75 μm to 100 μm, 100 μm to 125 μm, or 125 μm to 150 μm. Optionally, the bonding tolerance of the first back film BF1 is 100 μm. Optionally, the bending tolerance of the bending portion PBP is in a range of 50 μm to 150 μm, e.g., 50 μm to 75 μm, 75 μm to 100 μm, 100 μm to 125 μm, or 125 μm to 150 μm. Optionally, the bending tolerance of the bending portion PBP is 100 μm. Optionally, the third value is in a range of 100 μm to 200 μm, e.g., 100 μm to 125 μm, 125 μm to 150 μm, 150 μm to 175 μm, or 175 μm to 200 μm. Optionally, the third value is 150 μm. Optionally, the fifth shortest distance Ds5 is equal to or greater than 150 μm.

In some embodiments, referring to FIG. 8A to FIG. 8C, a sixth shortest distance Ds6 between the orthographic projection of the edge Ebf1 of the first back film BF1 adjacent to the bending portion PBP on the plane comprising the main surface Sm of the display portion DP and the orthographic projection of the boundary B2 between the fanout region FR and the bending portion PBP on the plane comprising the main surface Sm of the display portion DP is equal to or greater than a fourth value which is a composite tolerance calculated based on a bonding tolerance of the first back film BF1 and a material tolerance of the first back film BF1. Optionally, the fourth value is in a range of 100 μm to 200 μm, e.g., 100 μm to 125 μm, 125 μm to 150 μm, 150 μm to 175 μm, or 175 μm to 200 μm. Optionally, the fourth value is 150 μm. Optionally, the sixth shortest distance Ds6 is equal to or greater than 150 μm.

In some embodiments, referring to FIG. 8A to FIG. 8C, a seventh shortest distance Ds7 between the orthographic projection of the edge Ebf1 of the first back film BF1 adjacent to the bending portion PBP on the plane comprising the main surface Sm of the display portion DP and the orthographic projection of the edge Ept of the tapered portion adjacent to the polarizer PL on the plane comprising the main surface Sm of the display portion DP is equal to or greater than a fifth value which is a sum of a flow tolerance of the coating layer MCL, the bonding tolerance of the first back film BF1, and an overlength of a neutral plane NP of a structure comprising the bending portion PBP and the coating layer MCL. Optionally, the flow tolerance of the coating layer MCL is in a range of 150 μm to 250 μm, e.g., 150 μm to 175 μm, 175 μm to 200 μm, 200 μm to 225 μm, or 225 μm to 250 μm. Optionally, the flow tolerance of the coating layer MCL is 200 μm. Optionally, the bonding tolerance of the first back film BF1 is in a range of 50 μm to 150 μm, e.g., 50 μm to 75 μm, 75 μm to 100 μm, 100 μm to 125 μm, or 125 μm to 150 μm. Optionally, the bonding tolerance of the first back film BF1 is 100 μm. Optionally, the overlength of the neutral plane NP is in a range of 50 μm to 150 μm, e.g., 50 μm to 75 μm, 75 μm to 100 μm, 100 μm to 125 μm, or 125 μm to 150 μm. Optionally, the overlength of the neutral plane NP is 100 μm. Optionally, the fifth value is in a range of 300 μm to 500 μm, e.g., 300 μm to 350 μm, 350 μm to 400 μm, 400 μm to 450 μm, or 450 μm to 500 μm. Optionally, the fifth value is 400 μm. Optionally, the seventh shortest distance Ds7 is equal to or greater than 400 μm.

In some embodiments, referring to FIG. 8A to FIG. 8C, a distance d3 between the orthographic projection of the edge Ept of the tapered portion Pt adjacent to the polarizer PL on the plane comprising the main surface Sm of the display portion DP and the orthographic projection of the boundary B1 between the tapered portion Pt and the main portion on the plane comprising the main surface Sm of the display portion DP is less than 400 μm, e.g., less than 390 μm, less than 380 μm, less than 370 μm, less than 360 μm, or less than 350 μm.

FIG. 9A is a zoom-in view of a region circled by dotted line in FIG. 3 in some embodiments according to the present disclosure. Referring to FIG. 8A and FIG. 9A, in some embodiments, the coating layer MCL covering the back side of the bending portion PBP extends onto the first side S1 of the display portion DP by a first margin m1, and extends onto a side of the connecting portion CP opposite to the display portion DP by a second margin m2. Optionally, the first margin m1 and the second margin m2 are respectively in a range of 150 μm to 250 μm, e.g., 150 μm to 175 μm, 175 μm to 200 μm, 200 μm to 225 μm, or 225 μm to 250 μm. Optionally, the first margin m1 is 200 μm, and the second margin m2 is 200 μm (see, also, FIG. 4A).

FIG. 9B is a zoom-in view of a region circled by dotted line in FIG. 3 in some embodiments according to the present disclosure. Referring to FIG. 8A and FIG. 9B, in some embodiments, the coating layer MCL covering the back side of the bending portion PBP extends onto the first side S1 of the display portion DP by a first margin m1, and extends onto a side of the connecting portion CP opposite to the display portion DP by a second margin m2. Optionally, the second margin m2 is greater than the first margin m1 (see, also, FIG. 11).

FIG. 10 is a cross-sectional view around a bending portion of a display apparatus in some embodiments according to the present disclosure. Referring to FIG. 10, the display apparatus in some embodiments further includes a second optically clear adhesive layer OCA2 between the first back film BF1 and the support layer SL (e.g., a metal support layer), the second optically clear adhesive layer OCA2 adhering the first back film BF1 and the support layer SL together. Optionally, the display apparatus further includes an adhesive layer AL between the metal plate MP and the second back film BF2, the adhesive layer AL adhering the metal plate MP and the second back film BF2 together. Optionally, the support layer SL has a thickness in a range of 30 μm to 50 μm, e.g., 30 μm to 35 μm, 35 μm to 40 μm, 40 μm to 45 μm, or 45 μm to 50 μm. Optionally, the metal plate MP has a thickness in a range of 0.5 mm to 5 mm, e.g., 0.5 mm to 1.0 mm, 1.0 mm to 1.5 mm, 1.5 mm to 2.0 mm, 2.0 mm to 2.5 mm, 2.5 mm to 3.0 mm, 3.0 mm to 3.5 mm, 3.5 mm to 4.0 mm, 4.0 mm to 4.5 mm, or 4.5 mm to 5.0 mm. Optionally, the display apparatus further includes an Embo-type adhesive layer EMBO between the support layer SL and the metal plate MP. The Embo-type adhesive layer EMBO attaches the support layer SL and the metal plate MP together. The Embo-type adhesive layer EMBO has a mesh pattern structure that facilitates releasing air between the support layer SL and the metal plate MP when they are attached together. Optionally, the Embo-type adhesive layer EMBO has a thickness that is 1.5 times to 2.5 times of a thickness of the support layer SL.

FIG. 11 is a cross-sectional view around a bending portion of a display apparatus in some embodiments according to the present disclosure. Referring to FIG. 11, the display apparatus in some embodiments further includes an adhesive layer AL between the metal plate MP and the second back film BF2, the adhesive layer AL adhering the metal plate MP and the second back film BF2 together. Optionally, the display apparatus further includes a support layer SL between the metal plate MP and the first back film BF1. Optionally, the support layer SL includes a double-layer structure. Optionally, the support layer SL includes a metal support layer MS and a foam layer FM. Optionally, the display apparatus further includes an Embo-type adhesive layer EMBO between the metal support layer MS and the metal plate MP.

In some embodiments, the cover window CF of the display apparatus has a multi-layer structure. Optionally, the multi-layer structure includes a first cover sublayer CF1 on a side of the optically clear adhesive layer OCA away from the polarizer PL, an ultra thin glass UTG on a side of the first cover sublayer CF1 away from the optically clear adhesive layer OCA, and a second optically clear adhesive layer OCA2 between the ultra thin glass UTG and the first cover sublayer CF1, the second optically clear adhesive layer OCA2 adhering the ultra thin glass UTG and the first cover sublayer CF1 together. Optionally, the multi-layer structure further includes a second cover sublayer CF2 on a side of the ultra thin glass UTG away from the first cover sublayer CF1, and a third optically clear adhesive layer OCA3 between the ultra thin glass UTG and the second cover sublayer CF2, the third optically clear adhesive layer OCA3 adhering the ultra thin glass UTG and the second cover sublayer CF2 together. Optionally, the first cover sublayer CF1 and the second cover sublayer CF2 are made of an organic polymer such as polyamine or polyethylene terephthalate. Optionally, the second cover sublayer CF2 further includes a hard coating layer thereon. Optionally, the second cover sublayer CF2 further includes a protective film.

As shown in FIG. 11, an orthographic projection of the second cover sublayer CF2 on the display portion DP covers an orthographic projection of the ultra thin glass UTG on the display portion DP with a margin. An orthographic projection of the third optically clear adhesive layer OCA3 on the display portion DP and the orthographic projection of the ultra thin glass UTG on the display portion DP are substantially overlapping with each other, e.g., edges of the third optically clear adhesive layer OCA3 and the ultra thin glass UTG proximal to the coating layer MCL are flush with each other. The orthographic projection of the ultra thin glass UTG on the display portion DP covers an orthographic projection of the second optically clear adhesive layer OCA2 on the display portion DP with a margin. An orthographic projection of the optically clear adhesive layer OCA on the display portion DP and an orthographic projection of the polarizer PL on the display portion DP are substantially overlapping with each other, e.g., edges of the optically clear adhesive layer OCA and the polarizer PL proximal to the coating layer MCL are flush with each other.

Optionally, the orthographic projection of the first cover sublayer CF1 on the display portion DP and the orthographic projection of the second cover sublayer CF2 on the display portion DP are substantially overlapping with each other, and they cover the orthographic projection of the ultra thin glass UTG on the display portion DP with a margin.

Optionally, the optically clear adhesive layer OCA has a thickness in a range of 10 μm to 50 μm, e.g., 10 μm to 20 μm, 20 μm to 30 μm, 30 μm to 40 μm, or 40 μm to 50 μm. Optionally, the second optically clear adhesive layer OCA2 has a thickness in a range of 10 μm to 50 μm, e.g., 10 μm to 20 μm, 20 μm to 30 μm, 30 μm to 40 μm, or 40 μm to 50 μm. Optionally, the third optically clear adhesive layer OCA3 has a thickness in a range of 10 μm to 50 μm, e.g., 10 μm to 20 μm, 20 μm to 30 μm, 30 μm to 40 μm, or 40 μm to 50 μm. Optionally, the optically clear adhesive layer OCA has a thickness of 25 μm. Optionally, the second optically clear adhesive layer OCA2 has a thickness of 25 μm. Optionally, the third optically clear adhesive layer OCA3 has a thickness of 25 μm.

Optionally, the ultra thin glass UTG has a thickness in a range of 20 μm to 40 μm, e.g., 20 μm to 25 μm, 25 μm to 30 μm, 30 μm to 35 μm, or 35 μm to 40 μm. Optionally, the ultra thin glass UTG has a thickness of 30 μm.

Optionally, the first cover sublayer CF1 has a thickness in a range of 10 μm to 100 μm, e.g., 10 μm to 20 μm, 20 μm to 30 μm, 30 μm to 40 μm, 40 μm to 50 μm, 50 μm to 60 μm, 60 μm to 70 μm, 70 μm to 80 μm, 80 μm to 90 μm, or 90 μm to 100 μm. Optionally, the first cover sublayer CF1 has a thickness of 50 μm. Optionally, the first cover sublayer CF1 has a thickness of 55 μm. Optionally, the second cover sublayer CF2 has a thickness in a range of 10 μm to 100 μm, e.g., 10 μm to 20 μm, 20 μm to 30 μm, 30 μm to 40 μm, 40 μm to 50 μm, 50 μm to 60 μm, 60 μm to 70 μm, 70 μm to 80 μm, 80 μm to 90 μm, or 90 μm to 100 μm. Optionally, the second cover sublayer CF2 has a thickness of 50 μm. Optionally, the second cover sublayer CF2 has a thickness of 55 μm.

Optionally, the polarizer PL has a thickness in a range of 20 μm to 40 μm, e.g., 20 μm to 25 μm, 25 μm to 30 μm, 30 μm to 35 μm, or 35 μm to 40 μm. Optionally, the polarizer PL has a thickness of 31 μm.

Optionally, the metal support layer MS has a thickness in a range of 20 μm to 250 μm, e.g., 20 μm to 35 μm, 35 μm to 50 μm, 50 μm to 100 μm, 100 μm to 150 μm, 150 μm to 200 μm, or 200 μm to 250 μm. Optionally, the metal support layer MS has a thickness of 150 μm. Optionally, the metal support layer MS has a thickness of 40 μm.

Optionally, the foam layer FM has a thickness in a range of 50 μm to 210 μm, e.g., 50 μm to 70 μm, 70 μm to 90 μm, 90 μm to 110 μm, 110 μm to 130 μm, 130 μm to 150 μm, 150 μm to 170 μm, 170 μm to 190 μm, or 190 μm to 210 μm. Optionally, the foam layer FM has a thickness of 150 μm. Optionally, the foam layer FM has a thickness of 120 μm.

Optionally, the first back film BF1 has a thickness in a range of 10 μm to 100 μm, e.g., 10 μm to 20 μm, 20 μm to 30 μm, 30 μm to 40 μm, 40 μm to 50 μm, 50 μm to 60 μm, 60 μm to 70 μm, 70 μm to 80 μm, 80 μm to 90 μm, or 90 μm to 100 μm. Optionally, the first back film BF1 has a thickness of 50 μm. Optionally, the second back film BF2 has a thickness in a range of 10 μm to 100 μm, e.g., 10 μm to 20 μm, 20 μm to 30 μm, 30 μm to 40 μm, 40 μm to 50 μm, 50 μm to 60 μm, 60 μm to 70 μm, 70 μm to 80 μm, 80 μm to 90 μm, or 90 μm to 100 μm. Optionally, the second back film BF2 has a thickness of 50 μm.

Optionally, the display apparatus further include an ink layer between the first cover sublayer CF1 and the second optically clear adhesive layer OCA2. Optionally, the display apparatus further include a second ink layer between the second cover sublayer CF2 and the third optically clear adhesive layer OCA3. Optionally, the display apparatus further include a third ink layer between the ultra thin glass UTG and the second optically clear adhesive layer OCA3.

Optionally, the support layer SL includes a buffering material having buffering function, for example, an organic material such as a foam (e.g., the foam layer FM in FIG. 11). Optionally, the support layer SL includes a silicone. Optionally, the support layer SL includes a double-sided adhesive layer. Optionally, the support layer SL includes a metallic material such as stainless steel. Optionally, the support layer SL includes a foam layer and a polyethylene terephthalate layer. FIG. 12 illustrates a partial stacked structure including a support layer in some embodiments according to the present disclosure. Referring to FIG. 12, the support layer SL includes a foam layer FL and a polyethylene terephthalate layer PET. The display apparatus further include a second adhesive layer AL2 between the support layer SL and the metal support layer MS, the second adhesive layer SL2 including a pressure sensitive adhesive material.

In some embodiments, the display apparatus further includes a camera hole. Optionally, the first cover sublayer CF1 (and optionally the second cover sublayer CF2) covers the camera hole. The camera hole is underneath the first cover sublayer CF1 (and optionally the second cover sublayer CF2). The camera hole does not extend into the first cover sublayer CF1 (and optionally the second cover sublayer CF2).

In some embodiments, the coating layer MCL covers a first portion of the first back film BF1 by a first margin, and covers a second portion of the second portion of the second back film BF2 by a second margin. Optionally, the first margin and the second margin are different from each other. Optionally, the first margin is greater than the second margin. Optionally, the second margin is greater than the first margin.

Referring to FIG. 4A, FIG. 4B, and FIG. 11, in some embodiments, an orthographic projection of an edge Ecf of the cover window CF on a plane comprising the main surface Sm of the display portion DP is between an orthographic projection of the edge Ept of the tapered portion Pt adjacent to the polarizer PL on the plane comprising the main surface Sm of the display portion DP and an orthographic projection of the boundary B1 between the tapered portion Pt and the main portion Pm on the plane comprising the main surface Sm of the display portion DP. Optionally, the orthographic projection of the edge Ept of the tapered portion Pt adjacent to the polarizer PL on the plane comprising the main surface Sm of the display portion DP is between the orthographic projection of the edge Ecf of the cover window CF on the plane comprising the main surface Sm of the display portion DP and an orthographic projection of an edge of the polarizer PL on the plane comprising the main surface Sm of the display portion DP. Optionally, an orthographic projection of the edge Eoca connecting the first adhering surface Sa1 and the second adhering surface Sa2 on the plane comprising the main surface Sm of the display portion DP is aligned with the orthographic projection of the edge of the polarizer PL adjacent to the tapered portion Pt on the plane comprising the main surface Sm of the display portion DP, or is between the orthographic projection of the edge of the polarizer PL adjacent to the tapered portion Pt on the plane comprising the main surface Sm of the display portion DP and the orthographic projection of the edge Ecf of the cover window Cf adjacent to the tapered portion Pt on the plane comprising the main surface Sm of the display portion DP.

FIG. 13A is a cross-sectional view around a bending portion of a display apparatus in some embodiments according to the present disclosure. The structure of the display apparatus in FIG. 13A is similar to the structure of the display apparatus in FIG. 11, except for the layers between the first back film BF1 and the second back film BF2. Referring to FIG. 13, the display apparatus in some embodiments includes a support layer SL on a side of the first back film BF1 away from the display portion DP; a metal plate MP on a side of the support layer SL away from the first back film BF1; and a double-sided adhesive layer DAL between the metal plate MP and the second back film BF2. The double-sided adhesive layer DAL adheres the metal plate MP and the second back film BF2 together. Optionally, the support layer SL includes a buffering material having buffering function, for example, an organic material such as a foam (e.g., a foam layer).

FIG. 13B is a plan view of a support layer, a first back film, and a metal plate in some embodiments according to the present disclosure. Referring to FIG. 13A and FIG. 13B, in some embodiments, an orthographic projection of the metal plate MP on the display portion DP covers an orthographic projection of the support layer SL on the display portion DP with a margin. Optionally, an orthographic projection of the first back film BF1 on the display portion DP covers an orthographic projection of the metal plate MP on the display portion DP with a margin.

In another aspect, the present disclosure provides a method of fabricating a display apparatus. In some embodiments, the method includes forming a structure comprising a display panel having a display portion in a display region, a connecting portion, and a bending portion connecting the display portion and the connecting portion, wherein a flexible base substrate extends throughout the display portion, the bending portion and the connecting portion as a unitary structure that is substantially flat; forming a polarizer on a first side of the display portion; forming a cover window on the first side of the display portion, and on a side of the polarizer away from the display portion; forming a back film covering a surface of the flexible base substrate; removing a portion of the back film in a region having the bending portion, thereby forming a first back film covering a surface of the display portion and a second back film covering a surface of the connecting portion; bending the bending portion so that the first back film is facing the second back film, thereby forming a bending cavity that is surrounded by the bending portion; providing a metal plate between the display portion and the connecting portion; providing a support layer (e.g., a metal support layer) between the display portion and the connecting portion; forming a coating layer covering a back side of the bending portion opposite to a side directly surrounding the bending cavity. Optionally, the coating layer is formed to have a main portion, and a tapered portion extending from the main portion toward the polarizer. Optionally, a height of the tapered portion, relative to a main surface of the display portion on the first side, gradually increases from an edge of the tapered portion adjacent to the polarizer to a boundary between the tapered portion and the main portion. Optionally, the boundary is one at which the tapered portion has a maximum height relative to the main surface of the display portion on the first side. Optionally, the boundary is a boundary that is co-planar with an edge of the first back film proximal to the bending cavity. Optionally, an orthographic projection of the cover window on a plane comprising the main surface of the display portion is between an orthographic projection of the edge of the tapered portion adjacent to the polarizer on the plane comprising the main surface of the display portion and an orthographic projection of the boundary between the tapered portion and the main portion on the plane comprising the main surface of the display portion. Optionally, a first shortest distance between an orthographic projection of an edge of the polarizer adjacent to the tapered portion on the plane comprising the main surface of the display portion and the orthographic projection of the edge of the tapered portion adjacent to the polarizer on the plane comprising the main surface of the display portion is equal to or greater than a first value. Optionally, a second shortest distance between an orthographic projection of an edge of the cover window adjacent to the tapered portion on the plane comprising the main surface of the display portion and the orthographic projection of the boundary between the tapered portion and the main portion on the plane comprising the main surface of the display portion is also equal to or greater than the first value. As used herein, the term “substantially flat” may include small deviations from flat surface geometries, for example, deviations due to manufacturing processes.

FIG. 14A to FIG. 14D illustrate a method of fabricating a display apparatus in some embodiments. Referring to FIG. 14A, a structure having a display portion DP in a display region DR, a connecting portion CP, and a bending portion PBP connecting the display portion DP and the connecting portion CP is formed. A flexible base substrate FBS in the structure extends throughout the display portion DP, the bending portion PBP, and the connecting portion CP as a unitary structure that is substantially flat. A back film BF is formed to cover a surface of the flexible base substrate FBS, e.g., a surface of the flexible base substrate FBS on a side away from the cover window CF. On the first side S1 of the display portion DP, a polarizer PL is formed. An optically clear adhesive layer OCA is formed on the first side S1 of the display portion DP, and on a side of the polarizer PL away from the display portion DP. A cover window CF on the first side S1 of the display portion DP, and on a side of the optically clear adhesive layer OCA away from the polarizer PL. The optically clear adhesive layer OCA is formed between the polarizer PL and the cover window CF, the optically clear adhesive layer attaching the cover window CF to the polarizer PL.